CN112731713A

CN112731713A - Display device

Info

Publication number: CN112731713A
Application number: CN202110136108.3A
Authority: CN
Inventors: 陈明伦; 林义文; 陈政传
Original assignee: AU Optronics Corp
Current assignee: AU Optronics Corp
Priority date: 2020-07-08
Filing date: 2021-02-01
Publication date: 2021-04-30
Anticipated expiration: 2041-02-01
Also published as: TWI754318B; CN112731713B; TW202202917A

Abstract

The invention discloses a display device, which comprises a liquid crystal display panel and a backlight module. The backlight module comprises a light guide plate, a first light source, a second light source and a diffusion plate. The light guide plate is provided with a bottom surface, a light emergent surface and a light incident surface, wherein the light emergent surface is arranged opposite to the bottom surface, and the light incident surface is arranged between the bottom surface and the light emergent surface. The first light source is arranged beside the light incident surface of the light guide plate. The at least one optical film is arranged on the light-emitting surface of the light guide plate. The second light source, the diffusion plate, the light guide plate, the at least one optical film and the liquid crystal display panel are sequentially arranged. The display device of the invention can improve the mechanism and the result of phenomena of halo and/or color cast, and has good optical performance.

Description

Display device

Technical Field

The present disclosure relates to optoelectronic devices, and particularly to a display device.

Background

With the evolution of the photoelectric and semiconductor technologies, the development of flat panel displays has been driven. Among many flat panel displays, Liquid Crystal Displays (LCDs) have superior characteristics such as high space utilization efficiency, low power consumption, no radiation, and low electromagnetic interference, and have become the mainstream of the market. As is well known, a liquid crystal display includes a liquid crystal display panel (LCD panel) and a backlight module (backlight module), wherein the backlight module must be disposed under the liquid crystal display panel to provide a surface light source required by the liquid crystal display panel because the liquid crystal display panel itself does not have self-luminous characteristics. Therefore, the liquid crystal display can only display the image frame for the user to watch.

Fig. 1 shows the relationship between the viewing angle and the relative luminance of a conventional liquid crystal display at various gray-scale values L0, L32, L64, and L255 (the luminance ratio distribution of each gray-scale value based on the viewing angle of 0 degree). Referring to FIG. 1, in the prior art, the relative brightness of the LCD at high gray-scale values (e.g., L255) decreases with increasing viewing angle, but at low gray-scale values (e.g., L0, L32) the relative brightness of the LCD increases and then decreases with increasing viewing angle. In other words, in the conventional art, the trend of the viewing angle versus relative luminance curve of the liquid crystal display at a place having a high gray scale value is different from the trend of the viewing angle versus relative luminance curve at a place having a low gray scale value. Therefore, the conventional lcd has halo (halo effect) and/or color shift (color wash out) phenomena under a large viewing angle, which affects the optical performance of the lcd. The halo phenomenon is illustrated below with reference to fig. 2.

Fig. 2 shows a display screen of a known liquid crystal display viewed from a large angle of view. Referring to fig. 2, the display screen includes a first display area 20A and a second display area 20B, wherein the first display area 20A is used for displaying images with a lower average gray scale value (e.g., groves and night), and the second display area 20B is used for displaying images with a higher average gray scale value (e.g., castle). As shown in FIG. 2, when the conventional LCD is viewed at a large viewing angle, the first display area 20A for displaying images with low average gray scale values (e.g., groves and night) has an abnormal halo phenomenon.

Disclosure of Invention

The invention provides a display device with good optical performance.

The invention relates to a display device, which comprises a liquid crystal display panel and a backlight module. The backlight module comprises a light guide plate, a first light source, a second light source and a diffusion plate. The light guide plate is provided with a bottom surface, a light emergent surface and a light incident surface, wherein the light emergent surface is arranged opposite to the bottom surface, and the light incident surface is arranged between the bottom surface and the light emergent surface. The first light source is arranged beside the light incident surface of the light guide plate. The at least one optical film is arranged on the light-emitting surface of the light guide plate. The second light source, the diffusion plate, the light guide plate, the at least one optical film and the liquid crystal display panel are sequentially arranged. When the liquid crystal display panel has a first gray scale value, the first light source causes a first front brightness on the at least one optical film, the second light source causes a second front brightness on the at least one optical film, and the first front brightness is greater than the second front brightness. When the liquid crystal display panel has a second gray scale value larger than the first gray scale value, the first light source causes a third front brightness on the at least one optical film, the second light source causes a fourth front brightness on the at least one optical film, and the fourth front brightness is larger than the third front brightness.

In an embodiment of the invention, the diffusion plate has a light incident surface and a light emergent surface opposite to each other, and the light incident surface of the diffusion plate is located between the light emergent surface of the diffusion plate and the second light source; the first light source includes a plurality of first light emitting elements; the second light source includes a plurality of second light emitting elements; the at least one first light-emitting element generates a first light spot on the light-emitting surface of the light guide plate, the at least one second light-emitting element generates a second light spot on the light-emitting surface of the diffusion plate, the first light spot and the second light spot correspond to the same display area of the liquid crystal display panel, and the area of the first light spot is larger than that of the second light spot.

In an embodiment of the invention, the at least one optical film includes a first prism sheet and a second prism sheet disposed on the light exit surface of the light guide plate. The first prism sheet has a plurality of first prism structures. The second prism sheet is provided with a plurality of second prism structures, wherein the included angle between the extending direction of the first prism structures and the extending direction of the second prism structures is less than or equal to 30 degrees.

In an embodiment of the invention, the at least one optical film further includes: the reflective polarized light brightness enhancement film is arranged between the liquid crystal display panel and the second prism sheet.

In an embodiment of the invention, the reflective polarization brightness enhancement film has a plurality of protruding strip-shaped microstructures, wherein an included angle between an extending direction of the second prism structure and an extending direction of the strip-shaped microstructures is less than or equal to 30 °.

In an embodiment of the invention, the at least one optical film includes: the inverse prism lens is arranged on the light-emitting surface of the light guide plate and is provided with a plurality of inverse prism structures.

In an embodiment of the invention, the at least one optical film further includes: the reflective polarized light brightness enhancement film is arranged between the liquid crystal display panel and the inverse prism lens.

In an embodiment of the invention, the reflective polarization brightness enhancement film has a plurality of protruding strip-shaped microstructures, wherein an included angle between an extending direction of the inverse prism structure and an extending direction of the strip-shaped microstructures is less than or equal to 30 °.

In an embodiment of the invention, the light-emitting surface of the light guide plate has a plurality of protruding strip-shaped microstructures, and an extending direction of the strip-shaped microstructures of the light guide plate is substantially perpendicular to the light-incident surface of the light guide plate.

In an embodiment of the invention, the haze of the diffusion plate is greater than the haze of the light guide plate.

In an embodiment of the invention, the lcd panel has a first display area and a second display area, the first display area has a first gray scale value, and the second display area has a second gray scale value larger than the first gray scale value; the first light source causes first front brightness on a first position of the at least one optical film corresponding to the first display area, and the second light source causes second front brightness on a first position of the at least one optical film corresponding to the first display area; the first light source causes a third front brightness at a second position of the at least one optical film corresponding to the second display area, and the second light source causes a fourth front brightness at a second position of the at least one optical film corresponding to the second display area.

In an embodiment of the invention, the first illumination beam emitted by the first light source sequentially passes through the light incident surface of the light guide plate, the light exit surface of the light guide plate, the at least one optical film and the liquid crystal display panel to form a first image beam; the second illumination light beam emitted by the second light source sequentially passes through the diffusion plate, the bottom surface of the light guide plate, the light-emitting surface of the light guide plate, the at least one optical film and the liquid crystal display panel to form a second image light beam; the first image beam has a first full width at half maximum in one direction, the second image beam has a second full width at half maximum in the same direction, and the second full width at half maximum is larger than the first full width at half maximum.

In an embodiment of the invention, a difference between the second full width at half maximum and the first full width at half maximum falls within a range from 10 ° to 70 °.

The display device has the advantages that the mechanism and the result of phenomena of halation and/or color cast can be improved, and the optical performance is good.

Drawings

Fig. 1 shows the relationship between the viewing angle and the relative brightness of the conventional lcd at various gray-scale values L0, L32, L64 and L255.

Fig. 2 shows a display screen of a known liquid crystal display viewed from a large angle of view.

Fig. 3 is a schematic perspective view of a display device 10 according to an embodiment of the invention.

Fig. 4 shows the brightness of the display device 10 according to an embodiment of the present invention at each viewing angle.

Fig. 5 shows a display screen of the display device 10 according to an embodiment of the present invention.

Fig. 6 illustrates the display device 10 displaying the display screen of fig. 5.

Fig. 7 shows the brightness of the display device 10 according to an embodiment of the present invention at each viewing angle.

Fig. 8 shows gamma curves of the display device 10 according to the embodiment of the present invention at viewing angles θ of 30 °, θ of 45 ° and θ of 60 °.

Fig. 9 shows gamma curves of the display device 10 according to the embodiment of the present invention at viewing angles θ of 30 °, θ of 45 ° and θ of 60 °.

Fig. 10 shows gamma curves of the display device 10 according to the embodiment of the present invention at viewing angles θ of 30 °, θ of 45 ° and θ of 60 °.

Fig. 11 is a schematic perspective view of a display device 10A according to an embodiment of the invention.

Fig. 12 is a schematic perspective view of a display device 10B according to an embodiment of the invention.

Fig. 13 is a schematic cross-sectional view of a portion of a reflective polarization intensifying chip 153B according to an embodiment of the invention.

Fig. 14 shows the brightness of the display device 10B according to the embodiment of the present invention at each viewing angle.

Fig. 15 is a schematic perspective view of a display device 10C according to an embodiment of the invention.

Fig. 16 shows the luminance of the display device 10C according to the embodiment of the present invention at each viewing angle.

Fig. 17 is a schematic perspective view of a display device 10D according to an embodiment of the invention.

Fig. 18 shows the luminance of the display device 10D according to the embodiment of the present invention at each viewing angle.

Fig. 19 shows gamma curves of the display device 10 according to the embodiment of the present invention at viewing angles θ of 30 °, θ of 45 °, and θ of 60 °.

Fig. 20 shows a gamma curve of the display device 10D according to the embodiment of the present invention at viewing angles θ of 30 °, θ of 45 °, and θ of 60 °.

Fig. 21 shows gamma curves of the display device 10 according to the embodiment of the present invention at viewing angles θ of 30 °, θ of 45 °, and θ of 60 °.

Fig. 22 is a schematic perspective view of a display device 10E according to an embodiment of the invention.

Fig. 23 shows the luminance of the display device 10E according to the embodiment of the present invention at each viewing angle.

The reference numerals are explained below:

10. 10A, 10B, 10C, 10D, 10E display device

20A, 200A first display region

20B, 200B a second display area

100. 100A, 100B, 100C, 100D, 100E backlight module

110 second light source

112 second light emitting element

120 diffusion plate

121 incident light surface

122 light-emitting surface

130 first light source

132 first light emitting element

140 light guide plate

141 bottom surface

142 light emitting surface

142a strip-shaped microstructure

143 incident surface

150 optical film

151 first prism sheet

151a first prism structure

152 second prism sheet

152a second prism structure

153. 153B reflection type polarizing brightness enhancement film

153a surface

153a-1 bar microstructure

154 inverse prism lens

154a inverse prism structure

200 liquid crystal display panel

200a display surface

210 display area

d0, d1, d2, d3 and d4 in the extending direction

Direct type light emitting module

E, side-in type light emitting module

FWHM1 first full Width half maximum

FWHM2 second full Width half maximum

h is height

L1 first illumination Beam

L2 second illumination Beam

P1 first light spot

P2 second light spot

p is pitch

Curves S _ E, S _ D, S _ E + D1 and S _ E + D2

x, y, z directions

Detailed Description

Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the description to refer to the same or like parts.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. As used herein, "connected" may refer to physical and/or electrical connections. Further, "electrically connected" or "coupled" may mean that there are additional elements between the elements.

As used herein, "about", "approximately", or "substantially" includes the stated value and the average value within an acceptable range of deviation of the specified value as determined by one of ordinary skill in the art, taking into account the measurement in question and the specified amount of error associated with the measurement (i.e., the limitations of the measurement system). For example, "about" may mean within one or more standard deviations of the stated value, or within ± 30%, ± 20%, ± 10%, ± 5%. Further, as used herein, "about", "approximately" or "substantially" may be selected based on optical properties, etch properties, or other properties, with a more acceptable range of deviation or standard deviation, and not all properties may be applied with one standard deviation.

Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present invention and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Referring to fig. 3, the display device 10 includes a backlight module 100 and a liquid crystal display panel 200 disposed on the backlight module 100.

The liquid crystal display panel 200 includes an active device array substrate (not shown), an opposite substrate (not shown), and a liquid crystal layer (not shown) disposed between the active device array substrate and the opposite substrate. The active element array substrate is provided with a plurality of pixel structures. Each pixel structure comprises a thin film transistor, a data line electrically connected with a source electrode of the thin film transistor, a scanning line electrically connected with a grid electrode of the thin film transistor and a pixel electrode electrically connected with a drain electrode of the thin film transistor, wherein the data line is used for receiving a gray scale data signal, so that the pixel structure has a gray scale value (gray scale) corresponding to the gray scale data signal.

The backlight module 100 includes a second light source 110, a diffusion plate 120, a first light source 130, a light guide plate 140, and at least one optical film 150, wherein the second light source 110, the diffusion plate 120, the light guide plate 140, the at least one optical film 150, and the liquid crystal display panel 200 are sequentially arranged along a direction z.

The light guide plate 140 has a bottom surface 141, a light emitting surface 142 and a light incident surface 143, wherein the light emitting surface 142 is disposed opposite to the bottom surface 141, and the light incident surface 143 is disposed between the bottom surface 141 and the light emitting surface 142. The first light source 130 is disposed beside the light incident surface 143 of the light guide plate 140. The first light source 130 is configured to emit a first illumination light beam L1. The first illumination light beam L1 enters the light guide plate 140 from the light incident surface 143 of the light guide plate 140, is reflected by the bottom surface 141 of the light guide plate 140, and exits the light guide plate 140 from the light emitting surface 142 of the light guide plate 140. The first light source 130 and the light guide plate 140 can be regarded as an edge lighting type light emitting module E.

In the present embodiment, the light guide plate 140 may optionally have a function of collimating the first illumination light beam L1. For example, in the present embodiment, the bottom surface 141 and/or the light-emitting surface 142 of the light guide plate 140 may optionally have a plurality of optical microstructures (not shown); through the action of the plurality of optical microstructures, the divergence angle of the first illumination light beam L1 emitted from the light emitting surface 142 of the light guide plate 140 can be reduced, but the invention is not limited thereto.

In the present embodiment, the light guide plate 140 is, for example, a flat-type light guide plate (flat-type light guide plate). However, the invention is not limited thereto, and in other embodiments, the light guide plate 140 may also be a wedge-shaped light guide plate (wedge-shaped light guide plate) or other light guide plates.

The diffusion plate 120 is disposed on the second light source 110. The diffusion plate 120 has a light incident surface 121 and a light emitting surface 122 opposite to each other. The second light source 110 is configured to emit a second illumination beam L2. The second illumination light beam L2 enters the diffusion plate 120 from the light incident surface 121 of the diffusion plate 120, and exits the diffusion plate 120 from the light emitting surface 122 of the diffusion plate 120. The light incident surface 121 of the diffusion plate 120 is located between the light emitting surface 122 of the diffusion plate 120 and the second light source 110. The second light source 110 and the diffusion plate 120 can be regarded as a bottom lighting type light emitting module D.

In the present embodiment, the haze (haze) of the diffusion plate 120 is greater than that of the light guide plate 140. For example, the haze of the light guide plate 140 may be measured by: firstly, the light guide plate 140 is placed on a standard light source (such as, but not limited to, a surface light source) so that a standard light beam emitted by the standard light source enters the light guide plate 140 from the bottom surface 141 of the light guide plate 140 and leaves the light guide plate 140 from the light-emitting surface 142 of the light guide plate 140; then, a luminance meter is used to measure a first measurement area (for example, but not limited to: 1 cm) of the light-emitting surface 142 of the light guide plate 140 at a viewing angle²To obtain a first brightness of the first measurement region of the light guide plate 140; then, the light guide plate 140 on the standard light source is removed, and the luminance meter measures a second measurement area of the standard light source corresponding to the first measurement area of the light guide plate 140 at the same view angle, so as to obtain a second brightness of the second measurement area of the standard light source; the haze of the light guide plate 140 may be obtained by dividing the first luminance by the second luminance. Similarly, the haze of the diffuser plate 120 may be measured using the following method: firstly, the diffusion plate 120 is placed on the standard light source, so that the standard light beam emitted by the standard light source enters the diffusion plate 120 from the light incident surface 121 of the diffusion plate 120, and leaves the diffusion plate 120 from the light emitting surface 122 of the diffusion plate 120; next, a third measurement area (for example, but not limited to, 1 cm) of the light exit surface 122 of the diffuser plate 120 is measured at the same viewing angle using a luminance meter²To obtain a third luminance of a third measurement region of the diffusion plate 120; next, the diffuser 120 on the standard light source is removed and the luminance meter is measuredMeasuring a fourth measurement region of the standard light source corresponding to the third measurement region of the diffusion plate 120 at the same viewing angle to obtain a fourth luminance of the fourth measurement region of the standard light source; the haze of the diffusion plate 120 may be obtained by dividing the third luminance by the fourth luminance.

In this embodiment, both the side-in light-emitting module E and the direct-out light-emitting module D can emit light in different regions. For example, in the present embodiment, the first light source 130 of the side-entry light-emitting module E may include a plurality of first light-emitting elements 132 arranged beside the light-incident surface 143 of the light guide plate 140, and the plurality of first light-emitting elements 132 may be independently controlled. The first light emitting element 132 is, for example, a light emitting diode, but the invention is not limited thereto. The second light source 110 of the direct light-emitting module D may include a plurality of second light-emitting elements 112 disposed under the diffusion plate 120, and the plurality of second light-emitting elements 112 may be independently controlled. The second light emitting element 112 is, for example, a millimeter light emitting diode (mini LED), but the invention is not limited thereto.

In the embodiment, the first light emitting element 132 may cause the first light spot P1 on the light emitting surface 142 of the light guide plate 140, the second light emitting element 112 may cause the second light spot P2 on the light emitting surface 122 of the diffusion plate 120, the first light spot P1 and the second light spot P2 correspond to the same display region 210 of the liquid crystal display panel 200, and the area of the first light spot P1 is larger than the area of the second light spot P2, and the area of the second light spot P2 is larger than the area of the display region 210 of the liquid crystal display panel 200. The area of the display region 210 may refer to a region of the lcd panel 200 displaying the same and/or similar gray scales. In the present embodiment, the backlight module 100 has a local dimming (local dimming) capability.

The at least one optical film 150 is disposed on the light-emitting surface 142 of the light guide plate 140. At least one optical film 150 is disposed between the liquid crystal display panel 200 and the light guide plate 140. The direct light-emitting module D and the side light-emitting module E share at least one optical film 150. The direct light-emitting module D, the side light-emitting module E and the at least one optical film 150 form a composite backlight module 100.

In the present embodiment, the at least one optical film 150 may optionally include a first prism sheet 151 and a second prism sheet 152 disposed on the light emitting surface 142 of the light guide plate 140. The first prism sheet 151 has a plurality of first prism structures 151a, and the second prism sheet 152 has a plurality of second prism structures 152a, wherein an included angle (not shown) between an extending direction d1 of the plurality of first prism structures 151a and an extending direction d2 of the plurality of second prism structures 152a is less than or equal to 30 °. For example, in the present embodiment, an included angle between the extending direction d1 of the first prism structures 151a and the extending direction d2 of the second prism structures 152a may be substantially equal to 0 °; that is, the extending direction d1 of the first prism structures 151a and the extending direction d2 of the second prism structures 152a may be substantially parallel; however, the present invention is not limited thereto.

In the present embodiment, a plurality of first prism structures 151a of the first prism sheet 151 are formed on a surface of the first prism sheet 151 facing the liquid crystal display panel 200, and a plurality of second prism structures 152a of the second prism sheet 152 are formed on a surface of the second prism sheet 152 facing the liquid crystal display panel 200. That is, the first prism structure 151a and the second prism structure 152a may point away from the light guide plate 140, and the first prism sheet 151 and the second prism sheet 152 may be positive prisms.

In addition, in the present embodiment, the refractive index of the first prism sheet 151 and the refractive index of the second prism sheet 152 may be selectively the same. For example, in the present embodiment, the refractive index of the first prism sheet 151 and the refractive index of the second prism sheet 152 may both be 1.52. However, the invention is not limited thereto, and in another embodiment, the refractive indexes of the first prism sheet 151 and the second prism sheet 152 having the same refractive index may have other values; in yet another embodiment, the refractive index of the first prism sheet 151 and the refractive index of the second prism sheet 152 may also be different.

The first prism sheet 151 and the second prism sheet 152 are mainly used in cooperation with the side-in light-emitting module E to collimate the first illumination beam L1 emitted from the side-in light-emitting module E, so that the display device 10 achieves a desired optical performance. However, the present invention is not limited thereto, and in other embodiments, the first prism sheet 151 and/or the second prism sheet 152 disposed between the liquid crystal display panel 200 and the light guide plate 140 may be replaced by other types of optical films, depending on what optical performance the display device 10 is intended to achieve.

In addition, in the embodiment, the at least one optical film 150 disposed between the liquid crystal display panel 200 and the light guide plate 140 may further optionally include a Dual Brightness Enhancement Film (DBEF) 153. The first prism sheet 151, the second prism sheet 152 and the reflective polarization brightness enhancement film 153 are sequentially disposed on the light emitting surface 142 of the light guide plate 140 along the direction z. The reflective polarization brightness enhancement film 153 is disposed between the liquid crystal display panel 200 and the second prism film 152.

For example, in the present embodiment, the reflective polarizing brightness enhancement film 153 may include a substrate (not shown) formed by stacking a plurality of films and a plurality of optical microstructures (not shown) formed on the substrate. In the present embodiment, the plurality of optical microstructures of the reflective polarizing light intensifying plate 153 may be random and irregular microstructures. However, the invention is not limited thereto, and in another embodiment, other types of optical films may be used to replace the reflective polarizing brightness enhancement film 153; in another embodiment, the reflective polarizing plate 153 may be omitted.

Fig. 4 shows the brightness of the display device 10 according to an embodiment of the present invention at each viewing angle. The brightness at each viewing angle of fig. 4 is measured in a direction x (indicated in fig. 1). Referring to fig. 3, an angle C (not labeled) is included between the direction x and the extending direction d1 of the first prism structures 151a, where C is greater than or equal to 0 ° and less than or equal to 15 °; the direction x and the extending direction D2 of the plurality of second prism structures 152a form an angle D (not labeled), wherein D is greater than or equal to 0 degrees and less than or equal to 15 degrees. For example, in the present embodiment, angle C is substantially equal to 0 °; the angle D is substantially equal to 0 °, but the invention is not limited thereto.

Referring to fig. 3 and 4, the curve S _ E represents: when the first light source 130 of the side-in type light-emitting module E is turned on, the second light source 110 of the direct type light-emitting module D is turned off, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200 having the gray-scale value L255 is obtained. In other words, the first illumination light beam L1 emitted by the first light source 130 passes through the light incident surface 143 of the light guide plate 140, the light emitting surface 142 of the light guide plate 140, the optical film 150 and the liquid crystal display panel 200 having the gray scale value L255 sequentially to form a first image light beam (not shown), and the curve S _ E represents the normalized brightness of the first image light beam at each viewing angle. The first image beam has a first full width at half maximum (FWHM) 1 in the direction x.

Referring to fig. 3 and 4, the curve S _ D represents: when the first light source 130 of the side-in type light-emitting module E is turned off, the second light source 110 of the direct type light-emitting module D is turned on, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200 having the gray-scale value L255 is obtained. In other words, the second illumination light beam L2 emitted by the second light source 110 sequentially passes through the diffusion plate 120, the bottom surface 141 of the light guide plate 140, the light emitting surface 142 of the light guide plate 140, the optical film 150 and the liquid crystal display panel 200 having the gray scale value L255 to form a second image light beam, and the curve S _ D represents the normalized luminance of the second image light beam at each viewing angle. The second image light beam has a second full width at half maximum (FWHM) FWHM2 in the direction x.

The second full width at half maximum FWHM2 is greater than the first full width at half maximum FWHM 1. In other words, when the second illumination light beam L2 emitted by the direct light-emitting module D is transmitted to the light incident surface of the liquid crystal display panel 200 (i.e., the surface of the liquid crystal display panel 200 facing the backlight module 100), the second illumination light beam L2 is in a relatively divergent state; when the first illumination light beam L1 emitted by the side-in light-exiting module E is transmitted to the light-incident surface of the liquid crystal display panel 200, the first illumination light beam L1 is in a relatively collimated state.

In the present embodiment, the collimation degree of the first illumination light beam L1 provided by the side-in light-exiting module E may be significantly higher than the collimation degree of the second illumination light beam L2 provided by the direct-out light-exiting module D. For example, in the embodiment, the difference between the second full width at half maximum FWHM2 and the first full width at half maximum FWHM1 may fall within a range of 10 ° to 70 °.

It is noted that the components for providing the backlight to the LCD panel 200 (i.e., the ratio of the front brightness of the LCD panel 200 caused by the first illumination beam L1 to the front brightness of the LCD panel 200 caused by the second illumination beam L2) are determined according to the gray scale of the LCD panel 200. The various front luminances described herein are luminances measured in a direction substantially perpendicular to the display surface 200a of the liquid crystal display panel 200 (e.g., a direction opposite to the direction z in fig. 3).

Specifically, when the liquid crystal display panel 200 has a first gray scale value, the first light source 130 generates a first front brightness on the optical film 150 (such as but not limited to the reflective polarizing brightness enhancement film 153), the second light source 110 generates a second front brightness on the optical film 150 (such as but not limited to the reflective polarizing brightness enhancement film 153), and the first front brightness is greater than the second front brightness; when the liquid crystal display panel 200 has a second gray scale value larger than the first gray scale value, the first light source 130 generates a third front brightness on the optical film 150 (such as but not limited to the reflective polarizing brightness enhancement film 153), the second light source 110 generates a fourth front brightness on the optical film 150 (such as but not limited to the reflective polarizing brightness enhancement film 153), and the fourth front brightness is larger than the third front brightness.

In short, when the liquid crystal display panel 200 has a low gray scale value, the backlight of the liquid crystal display panel 200 is mainly provided by the relatively collimated first illumination light beam L1; when the liquid crystal display panel 200 has a high gray scale value, the backlight of the liquid crystal display panel 200 is mainly provided by the second illumination light beam L2 which is relatively divergent.

For example, in the embodiment, when the liquid crystal display panel 200 has a gray scale value of L10 corresponding to 4% of the highest transmittance of the liquid crystal display panel 200, the first illumination light beam L1 provided by the side-in light-exiting module E causes a brightness LM1 on one position of the optical film 150, the second illumination light beam L2 provided by the direct-out light-exiting module D causes a brightness LM4 on the same position of the same optical film 150, and LM1> LM 4; when the lcd panel 200 has an L192 gray scale value corresponding to 75% of the highest transmittance of the lcd panel 200, the first illuminating light beam L1 provided by the side-in light-exiting module E causes a brightness LM2 on one position of the optical film 150, and the second illuminating light beam L2 provided by the direct-out light-exiting module D causes a brightness LM5 on the same position of the same optical film 150, and LM5> LM 2; when the lcd panel 200 has an L255 gray scale value corresponding to 100% of the highest transmittance of the lcd panel 200, the first illuminating light beam L1 provided by the side-in light-exiting module E causes a brightness LM3 on one position of the optical film 150, and the second illuminating light beam L2 provided by the direct-out light-exiting module D causes a brightness LM6 on the same position of the same optical film 150, and LM6> LM 3.

Since the backlight component provided to the lcd panel 200 is determined according to the gray scale value of the lcd panel 200, the display device 10 can improve halo (halo effect) and/or color shift (color wash out) phenomena described in the prior art, and the mechanism and improvement result thereof will be described below with reference to other figures.

Fig. 6 illustrates the display device 10 displaying the display screen of fig. 5. In particular, fig. 6 shows the operation state of the side-in type light-emitting module E and the direct-out type light-emitting module D of the display device 10 under the display screen of fig. 5.

Fig. 7 shows the brightness of the display device 10 according to an embodiment of the present invention at each viewing angle. Referring to fig. 3 and 7, the curve S _ E of fig. 7 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned off, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200. The curve S _ E + D1 of fig. 7 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned on and has a weaker first light intensity, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200. The curve S _ E + D2 of fig. 7 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned on, and has a stronger second light intensity, and the liquid crystal display panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the liquid crystal display panel 200 is obtained.

Referring to fig. 5 and 6, the lcd panel 200 has a first display area 200A and a second display area 200B, wherein the first display area 200A has a first gray scale value, and the second display area 200B has a second gray scale value larger than the first gray scale value. For example, in the present embodiment, the second display area 200B of the lcd panel 200 displays a brighter (i.e., having a higher gray-scale value) castle, and the first display area 200A of the lcd panel 200 displays a darker (i.e., having a lower gray-scale value) grove and night.

The first light source 130 of the side-in light-emitting module E generates a first brightness at a first position 150A of the optical film 150 corresponding to the first display area 200A (e.g., an area displaying a low gray scale value of a tree and night), and the second light source 110 of the direct-out light-emitting module D generates a second brightness at the same first position 150A, wherein the first brightness is greater than the second brightness. For example, in the present embodiment, the second light emitting element 112 of the second light source 110 corresponding to the first display area 200A is turned off, the first light emitting element 132 of the first light source 130 corresponding to the first display area 200A is turned on, and the main component of the backlight transmitted to the first display area 200A (e.g., the area displaying the low gray scale value of the groves and the night) is the collimated first illumination light beam L1; at this time, the light shape distribution of the illumination light beam provided by the composite backlight module 100 corresponding to the first display area 200A is equal to or close to the curve S _ E of fig. 7.

The first light source 130 causes a third brightness at a second location 150B of the optical film 150 corresponding to a second display area 200B (e.g., a region of a castle displaying high gray scale values), and the second light source 110 causes a fourth brightness at the same second location 150B, wherein the fourth brightness is greater than the third brightness. For example, in the present embodiment, the second light emitting element 112 of the second light source 110 corresponding to the second display area 200B is turned on, and the first light emitting element 132 of the first light source 130 corresponding to the second display area 200B is also turned on. The light intensity of the first illumination light beam L1 provided by the direct light-emitting module D is much greater than the light intensity of the second illumination light beam L2 provided by the side light-emitting module E; at this time, the main component of the backlight transmitted to the second display area 200B (e.g. the region of the castle displaying high gray scale values) is the more divergent first illumination beam L1, and the light shape distribution of the illumination beam provided by the composite backlight module 100 corresponding to the second display area 200B is closer to the curve S _ E + D2 of fig. 7.

Referring to fig. 5, fig. 6 and fig. 7, the light shape distribution of the illumination beam of the composite backlight module 100 at the position corresponding to the first display area 200A (e.g., the area displaying the low gray scale value of the groves and the night) is closer to the curve S _ E with the narrower half-height width of fig. 7. That is, the illumination beam of the composite backlight module 100 corresponding to the first display area 200A with a low gray scale value will be transmitted in a low proportion toward the large viewing angle. Therefore, in the case where the display device 10 is viewed at a large viewing angle, the luminance of the second display region 200B having a low gray-scale value is not easily high.

The light shape distribution of the illumination beam of the composite backlight module 100 corresponding to the second display region 200B (e.g., the region of the castle displaying high gray scale values) is closer to the curve S _ E + D2 with wider half width at half maximum of fig. 7. That is, the illumination beam of the composite backlight module 100 corresponding to the second display area 200B with the high gray scale value will be transmitted in a higher proportion toward the large viewing angle. Therefore, in the case where the display device 10 is viewed at a large viewing angle, the second display region 200B having a high gray scale value still maintains high luminance at the large viewing angle.

Therefore, when the display device 10 is viewed from a large viewing angle, the first display area 200A and the second display area 200B having a low gray scale value and a high gray scale value respectively can display a more correct luminance, thereby improving halo (halo effect) and/or color shift (color wash out) phenomena of the display device in the prior art at the large viewing angle.

Fig. 8 shows gamma curves (gamma curves) of the display device 10 according to an embodiment of the invention at viewing angles θ of 30 °, θ of 45 ° and θ of 60 °, wherein when the gray scale value of the liquid crystal display panel 200 of the display device 10 is in a range from L0 to L32, the lateral light-emitting module E of the display device 10 is turned on to the maximum power, and the direct light-emitting module D is turned off.

Referring to fig. 8, at the viewing angle θ of 30 °, the gamma average of the gray-scale values L32 to L192 is 2.2; the gamma average of the grayscale values L32 to L192 is 2.1 at the viewing angle θ of 45 °; the gamma average of the grayscale values L32 to L192 is 1.9 at the viewing angle θ of 60 °. As can be seen from fig. 8, when the gray-scale value of the liquid crystal display panel 200 falls within the range from L0 to L32, the power of the side-in light-emitting module E is turned on to the maximum, and the direct-out light-emitting module D is turned off, the gamma average value of the gray-scale values L32 to L192 is equal to or close to 2.2 when the viewing angle θ is 30 °, the viewing angle θ is 45 °, and the viewing angle θ is 60 °.

Fig. 9 shows gamma curves (gamma curves) of the display device 10 according to an embodiment of the invention at viewing angles θ of 30 °, θ of 45 ° and θ of 60 °, wherein when the gray scale value of the liquid crystal display panel 200 of the display device 10 is in a range from L0 to L16, the lateral light-emitting module E of the display device 10 is turned on to the maximum power, and the direct light-emitting module D is turned off.

Referring to fig. 9, at the viewing angle θ of 30 °, the gamma average of the gray-scale values L32 to L192 is 2.1; the gamma average of the grayscale values L32 to L192 is 1.9 at the viewing angle θ of 45 °; the gamma average of the grayscale values L32 to L192 is 1.7 at the viewing angle θ of 60 °. As can be seen from fig. 9, when the gray-scale value of the liquid crystal display panel 200 falls within the range from L0 to L16, the power of the side-in light-emitting module E is turned on to the maximum, and the direct-out light-emitting module D is turned off, the gamma average value of the gray-scale values L32 to L192 is equal to or close to 2.2 when the viewing angle θ is 30 °, the viewing angle θ is 45 °, and the viewing angle θ is 60 °.

Fig. 10 shows gamma curves (gamma curves) of the display device 10 according to an embodiment of the invention under viewing angles θ of 30 °, θ of 45 ° and θ of 60 °, wherein when the gray scale value of the liquid crystal display panel 200 of the display device 10 is in a range from L0 to L8, the lateral light-emitting module E of the display device 10 is turned on to the maximum power, and the direct light-emitting module D is turned off.

Please refer to fig. 10; the gamma average of the grayscale values L32 to L192 is 2.0 at the viewing angle θ of 30 °; the gamma average of the grayscale values L32 to L192 is 1.8 at the viewing angle θ of 45 °; the gamma average of the grayscale values L32 to L192 is 1.6 at the viewing angle θ of 60 °. As can be seen from fig. 10, when the gray-scale value of the liquid crystal display panel 200 falls within the range from L0 to L8, the power of the side-in light-emitting module E is turned on to the maximum, and the direct-out light-emitting module D is turned off, the gamma average value of the gray-scale values L32 to L192 is equal to or close to 2.2 when the viewing angle θ is 30 °, the viewing angle θ is 45 °, and the viewing angle θ is 60 °.

As can be seen from fig. 8, 9 and 10, no matter what range of low gray-scale values the liquid crystal display panel 200 has, the lateral light-emitting module E contributes more luminance and the direct light-emitting module D contributes less luminance (or does not contribute luminance), which is helpful to improve the color shift problem of the display device 10 at a large viewing angle. As can be seen from fig. 8, 9 and 10, the larger the gray scale range of the liquid crystal display panel 200 corresponding to the case where the side-in light-emitting module E contributes more luminance and the direct-out light-emitting module D contributes less luminance (or does not contribute luminance), the more the color shift problem of the display device 10 at a large viewing angle is improved.

It should be noted that the following embodiments follow the reference numerals and parts of the contents of the foregoing embodiments, wherein the same reference numerals are used to indicate the same or similar elements, and the description of the same technical contents is omitted. For the description of the omitted portions, reference may be made to the foregoing embodiments, which will not be repeated below.

Fig. 11 is a schematic perspective view of a display device 10A according to an embodiment of the invention. The display device 10A of fig. 11 is similar to the display device 10 described above, and the difference therebetween is that: in the embodiment of fig. 11, the light emitting surface 142A of the light guide plate 140 of the backlight module 100A has a plurality of protruding bar-shaped microstructures 142A, and the extending direction d0 of the bar-shaped structures 142A of the light guide plate 140 is substantially perpendicular to the light incident surface 143 of the light guide plate 140. The strip-shaped microstructures 142A of the light-emitting surface 142A of the light guide plate 140 are used to limit the distribution range of the first illumination light beam L1 emitted by each first light-emitting element 132 on the light-emitting surface 142A (i.e., the size of the first light spot P1 caused by each first light-emitting element 132). By using the effect of the stripe microstructures 142a, local dimming (local dimming) capability of the display device 10A can be optimized. For example, in the embodiment, the plurality of bar structures 142a of the light guide plate 140 may be a plurality of lenticular microstructures (lenticules), but the invention is not limited thereto.

Fig. 12 is a schematic perspective view of a display device 10B according to an embodiment of the invention. The display device 10B of fig. 12 is similar to the display device 10 described above, and the difference therebetween is that: in the embodiment of fig. 12, the reflective polarizing brightness enhancement film 153B has a plurality of protruding stripe-shaped microstructures 153 a-1. The plurality of stripe-shaped microstructures 153a-1 are formed on the surface 153a of the reflective polarizing brightness enhancement film 153B facing the liquid crystal display panel 200. The plurality of stripe-shaped microstructures 153a-1 can reduce the divergence degree of the first illumination light beam L1 and/or the second illumination light beam L2 in the direction y, thereby realizing the display device 10B with the peep-proof effect in the direction y.

An included angle (not shown) between the extending direction d2 of the second prism structure 152a of the second prism sheet 152 and the extending direction d3 of the strip-shaped microstructure 153a-1 of the reflective polarization brightness enhancement film 153B is less than or equal to 30 °. For example, in the present embodiment, an included angle between the extending direction d2 of the second prism structure 152a and the extending direction d3 of the bar-shaped microstructure 153a-1 may be substantially equal to 0 °; that is, the second prism structure 152a and the bar-shaped microstructure 153a-1 may be substantially parallel; however, the present invention is not limited thereto.

Referring to fig. 13, in the present embodiment, the plurality of protruding stripe-shaped microstructures 153a-1 of the reflective polarization brightness enhancement film 153B are arranged along the direction y, the plurality of protruding stripe-shaped microstructures 153a-1 have a plurality of pitches P in the direction y, an average value of the plurality of pitches P is P, each protruding stripe-shaped microstructure 153a-1 has a height H in the direction z, an average value of the plurality of heights H of the plurality of stripe-shaped microstructures 153a-1 is H, and 4% or more (H/P) or less is 25%. In the embodiment, the plurality of protruded stripe microstructures 153a-1 of the reflective polarizing plate 153B may be a plurality of lenticular microstructures (lenticules).

Fig. 14 shows the brightness of the display device 10B according to the embodiment of the present invention at each viewing angle. Referring to fig. 12 and 14, the curve S _ E of fig. 14 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned off, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200. The curve S _ E + D1 of fig. 14 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned on and has a weaker first light intensity, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200. The curve S _ E + D2 of fig. 14 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned on, and has a stronger second light intensity, and the liquid crystal display panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the liquid crystal display panel 200 is obtained.

The curve S _ E in fig. 14 can reflect the distribution of the illumination light beams provided by the composite backlight module 100B to the lcd panel 200 when the first light source 130 of the side-in light-emitting module E is turned on and the second light source 110 of the direct-out light-emitting module D is turned off. The curve S _ E + D1 in fig. 14 can reflect the distribution of the illumination light beams provided by the composite backlight module 100B to the lcd panel 200 when the first light source 130 of the side-in light-exiting module E is turned on, the second light source 110 of the direct-out light-exiting module D is turned on, and the first light intensity is weaker. The curve S _ E + D2 in fig. 14 can reflect the distribution of the illumination light beams provided by the composite backlight module 100B to the lcd panel 200 when the first light source 130 of the side-in light-exiting module E is turned on, the second light source 110 of the direct-out light-exiting module D is turned on, and the second light intensity is stronger.

Similar to the display device 10, in the present embodiment, the backlight component provided to the lcd panel 200 of the display device 10B is determined according to the gray-scale value of the lcd panel 200 of the display device 10B, so that the display device 10B can also improve the halo (halo effect) and/or color shift (color wash out) phenomenon described in the prior art. The mechanism of the display device 10B for improving the halo and/or color shift phenomenon can be known by those skilled in the art with reference to fig. 12, fig. 14 and the foregoing description, and will not be repeated here.

Fig. 15 is a schematic perspective view of a display device 10C according to an embodiment of the invention. The display device 10C of fig. 15 is similar to the display device 10B of fig. 12, and the difference therebetween is that: in the embodiment of fig. 12, the refractive index of the first prism sheet 151 and the refractive index of the second prism sheet 152 of the backlight module 100B may both be 1.52; however, in the embodiment of fig. 15, the refractive index of the first prism sheet 151 of the backlight module 100C is 1.52, but the refractive index of the second prism sheet 152 is 1.62.

Fig. 16 shows the luminance of the display device 10C according to the embodiment of the present invention at each viewing angle. Referring to fig. 15 and 16, the curve S _ E of fig. 16 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned off, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200. The curve S _ E + D1 of fig. 16 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned on and has a weaker first light intensity, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200. The curve S _ E + D2 of fig. 16 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned on, and has a stronger second light intensity, and the liquid crystal display panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the liquid crystal display panel 200 is obtained.

The curve S _ E in fig. 16 can reflect the distribution of the illumination light beams provided by the composite backlight module 100C to the lcd panel 200 when the first light source 130 of the side-in light-emitting module E is turned on and the second light source 110 of the direct-out light-emitting module D is turned off. The curve S _ E + D1 in fig. 16 can reflect the distribution of the illumination light beams provided by the composite backlight module 100C to the lcd panel 200 when the first light source 130 of the side-in light-exiting module E is turned on, the second light source 110 of the direct-out light-exiting module D is turned on, and the first light intensity is weaker. The curve S _ E + D2 in fig. 16 can reflect the distribution of the illumination light beams provided by the composite backlight module 100C to the lcd panel 200 when the first light source 130 of the side-in light-exiting module E is turned on, the second light source 110 of the direct-out light-exiting module D is turned on, and the second light intensity is stronger.

Similar to the display device 10, in the present embodiment, the backlight component provided to the lcd panel 200 of the display device 10C is determined according to the gray-scale value of the lcd panel 200 of the display device 10C, so that the display device 10C can also improve the halo (halo effect) and/or color shift (color wash out) phenomenon described in the prior art. The mechanism of the display device 10C for improving the halo and/or color shift phenomenon can be known by those skilled in the art with reference to fig. 15, fig. 16 and the foregoing description, and will not be repeated here.

Fig. 17 is a schematic perspective view of a display device 10D according to an embodiment of the invention. The display device 10D of fig. 17 is similar to the display device 10 described above, and the difference therebetween is that: the optical film 150 between the liquid crystal display panel 200 and the light guide plate 140 of fig. 17 is different from the optical film 150 between the liquid crystal display panel 200 and the light guide plate 140 of fig. 2.

Referring to fig. 17, in the present embodiment, the optical film 150 disposed between the liquid crystal display panel 200 and the light guide plate 140 includes a reverse prism lens 154 and a reflective polarization brightness enhancement film 153. The inverse Prism lens 154 is disposed on the light emitting surface 142 of the light guide plate 140 and has a plurality of inverse Prism (Reverse Prism) structures 154 a. The plurality of inverse prism structures 154a have an extension direction d 4. The inverse prism structure 154a is formed on a surface of the inverse prism sheet 154 facing away from the liquid crystal display panel 200. The reflective polarization brightness enhancement film 153 is disposed between the liquid crystal display panel 200 and the reverse prism 154.

Fig. 18 shows the luminance of the display device 10D according to the embodiment of the present invention at each viewing angle. Referring to fig. 17 and 18, the curve S _ E of fig. 18 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned off, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200. The curve S _ E + D1 of fig. 18 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned on and has a weaker first light intensity, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200. The curve S _ E + D2 of fig. 18 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned on, and has a stronger second light intensity, and the liquid crystal display panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the liquid crystal display panel 200 is obtained.

The curve S _ E in fig. 18 can reflect the distribution of the illumination light beams provided by the composite backlight module 100D to the lcd panel 200 when the first light source 130 of the side-in light-emitting module E is turned on and the second light source 110 of the direct-out light-emitting module D is turned off. The curve S _ E + D1 in fig. 18 can reflect the distribution of the illumination light beams provided by the composite backlight module 100D to the lcd panel 200 when the first light source 130 of the side-in light-exiting module E is turned on, the second light source 110 of the direct-out light-exiting module D is turned on, and the first light intensity is weaker. The curve S _ E + D2 in fig. 18 can reflect the distribution of the illumination light beams provided by the composite backlight module 100D to the lcd panel 200 when the first light source 130 of the side-in light-exiting module E is turned on, the second light source 110 of the direct-out light-exiting module D is turned on, and the second light intensity is stronger.

Fig. 19 shows gamma curves (gamma curves) of the display device 10 according to an embodiment of the invention under viewing angles θ of 30 °, θ of 45 ° and θ of 60 °, wherein when the gray scale value of the liquid crystal display panel 200 of the display device 10D is in a range from L0 to L32, the lateral light-emitting module E of the display device 10D is turned on to the maximum power, and the direct light-emitting module D is turned off.

Referring to fig. 19, the gamma average of the gray-scale values L32 to L192 is 2.3 at the viewing angle θ of 30 °; the gamma average of the grayscale values L32 to L192 is 2.2 at the viewing angle θ of 45 °; the gamma average of the grayscale values L32 to L192 is 2.1 at the viewing angle θ of 60 °. As can be seen from fig. 19, when the gray-scale value of the liquid crystal display panel 200 falls within the range from L0 to L32, the power of the side-in light-emitting module E is turned on to the maximum, and the direct-out light-emitting module D is turned off, the gamma average value of the gray-scale values L32 to L192 is equal to or close to 2.2 at the viewing angle θ of 30 °, the viewing angle θ of 45 °, and the viewing angle θ of 60 ° of the display device 10D.

Fig. 20 shows gamma curves (gamma curves) of the display device 10D according to an embodiment of the invention under the viewing angles θ ═ 30 °, θ ═ 45 ° and θ ═ 60 °, wherein when the gray scale value of the liquid crystal display panel 200 of the display device 10D is in the range from L0 to L16, the lateral light-emitting module E of the display device 10D is turned on to the maximum power, and the direct light-emitting module D is turned off.

Referring to fig. 20, at the viewing angle θ of 30 °, the gamma average of the gray-scale values L32 to L192 is 2.1; the gamma average of the grayscale values L32 to L192 is 2.0 at the viewing angle θ of 45 °; the gamma average of the grayscale values L32 to L192 is 1.8 at the viewing angle θ of 60 °. As can be seen from fig. 20, when the gray-scale value of the liquid crystal display panel 200 falls within the range from L0 to L16, the power of the side-in light-emitting module E is turned on to the maximum, and the direct-out light-emitting module D is turned off, the gamma average value of the gray-scale values L32 to L192 is equal to or close to 2.2 at the viewing angle θ of 30 °, the viewing angle θ of 45 °, and the viewing angle θ of 60 ° of the display device 10D.

Fig. 21 shows gamma curves (gamma curves) of the display device 10 according to an embodiment of the invention under the viewing angles θ ═ 30 °, θ ═ 45 ° and θ ═ 60 °, wherein when the gray scale value of the liquid crystal display panel 200 of the display device 10D is in the range from L0 to L8, the lateral light-emitting module E of the display device 10D is turned on to the maximum power, and the direct light-emitting module D is turned off.

Referring to fig. 21, the gamma average of the gray-scale values L32 to L192 is 2.1 when the viewing angle θ is 30 °; the gamma average of the grayscale values L32 to L192 is 1.9 at the viewing angle θ of 45 °; the gamma average of the grayscale values L32 to L192 is 1.7 at the viewing angle θ of 60 °. As can be seen from fig. 21, when the gray-scale value of the liquid crystal display panel 200 falls within the range from L0 to L8, the power of the side-in light-emitting module E is turned on to the maximum, and the direct-out light-emitting module D is turned off, the gamma average value of the gray-scale values L32 to L192 is equal to or close to 2.2 when the viewing angle θ is 30 °, the viewing angle θ is 45 °, and the viewing angle θ is 60 °.

Similar to the display device 10, in the present embodiment, the backlight component provided to the lcd panel 200 of the display device 10D is determined according to the gray-scale value of the lcd panel 200 of the display device 10D, so that the display device 10D can also improve the halo (halo effect) and/or color shift (color wash out) phenomenon described in the prior art. The mechanism and the result of the display device 10D capable of improving the phenomena of halo and/or color shift will be clear to those skilled in the art with reference to fig. 17 to 21 and the foregoing description, and will not be repeated here.

Fig. 22 is a schematic perspective view of a display device 10E according to an embodiment of the invention. The display device 10E of fig. 22 is similar to the display device 10D of fig. 17, and the difference therebetween is that: in the embodiment of fig. 17, the reflective polarization intensifying chip 153 includes a substrate (not shown) formed by stacking multiple films and a plurality of optical microstructures (not shown) formed on the substrate, wherein the optical microstructures of the reflective polarization intensifying chip 153 may be random and irregular microstructures; in the embodiment of fig. 22, the reflective polarization intensifying chip 153B includes a substrate (not shown) formed by stacking multiple films and a plurality of optical microstructures (not shown) formed on the substrate, but the plurality of optical microstructures of the reflective polarization intensifying chip 153B are convex strip-shaped microstructures 153 a-1. Referring to fig. 22, an angle (not shown) between the extending direction d4 of the reverse prism structure 154a of the reverse prism lens 154 and the extending direction d3 of the strip-shaped microstructure 153a-1 of the reflective polarization brightness enhancement film 153 is less than or equal to 30 °. For example, in the present embodiment, an angle between the extending direction d4 of the reverse prism structure 154a of the reverse prism lens 154 and the extending direction d3 of the strip-shaped microstructure 153a-1 of the reflective polarization brightness enhancement film 153 may be substantially equal to 0 °; that is, the inverse prism structure 154a of the inverse prism lens 154 and the strip-shaped microstructure 153a-1 of the reflective polarization brightness enhancement film 153 can be substantially parallel; however, the present invention is not limited thereto.

Fig. 23 shows the luminance of the display device 10E according to the embodiment of the present invention at each viewing angle. Referring to fig. 22 and 23, the curve S _ E of fig. 23 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned off, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200. The curve S _ E + D1 of fig. 23 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned on and has a weaker first light intensity, and the lcd panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the lcd panel 200. The curve S _ E + D2 of fig. 23 represents: when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned on, and has a stronger second light intensity, and the liquid crystal display panel 200 is switched to the gray-scale value L255, the normalized luminance at each viewing angle measured on the liquid crystal display panel 200 is obtained.

The curve S _ E in fig. 23 can reflect the distribution of the illumination light beams provided by the composite backlight module 100E to the lcd panel 200 when the first light source 130 of the side-in light-emitting module E is turned on and the second light source 110 of the direct-out light-emitting module D is turned off. The curve S _ E + D1 in fig. 23 can reflect the distribution of the illumination light beams provided by the composite backlight module 100E to the lcd panel 200 when the first light source 130 of the side-in light-emitting module E is turned on, the second light source 110 of the direct-out light-emitting module D is turned on, and the first light intensity is weaker. The curve S _ E + D2 in fig. 23 can reflect the distribution of the illumination light beams provided by the composite backlight module 100E to the lcd panel 200 when the first light source 130 of the side-in light-exiting module E is turned on, the second light source 110 of the direct-out light-exiting module D is turned on, and the second light intensity is stronger.

Similar to the display device 10, in the present embodiment, the backlight component provided to the lcd panel 200 of the display device 10E is determined according to the gray scale value of the lcd panel 200 of the display device 10E, so that the display device 10B can also improve the halo (halo effect) and/or color shift (color wash out) phenomenon described in the prior art. The mechanism of the display device 10E for improving the halo and/or color shift phenomenon can be known by those skilled in the art with reference to fig. 22, 23 and the foregoing description, and will not be repeated here.

Claims

1. A display device, comprising:

a liquid crystal display panel; and

a backlight module, comprising:

a light guide plate having a bottom surface, a light emergent surface and a light incident surface, wherein the light emergent surface is disposed opposite to the bottom surface, and the light incident surface is disposed between the bottom surface and the light emergent surface;

the first light source is arranged beside the light incident surface of the light guide plate;

at least one optical film arranged on the light emergent surface of the light guide plate;

a second light source; and

a diffusion plate, wherein the second light source, the diffusion plate, the light guide plate, the at least one optical film and the liquid crystal display panel are sequentially arranged;

when the liquid crystal display panel has a first gray scale value, the first light source causes a first front brightness on the at least one optical film, the second light source causes a second front brightness on the at least one optical film, and the first front brightness is greater than the second front brightness;

when the liquid crystal display panel has a second gray scale value larger than the first gray scale value, the first light source causes a third front brightness on the at least one optical film, the second light source causes a fourth front brightness on the at least one optical film, and the fourth front brightness is larger than the third front brightness.

2. The display device as claimed in claim 1, wherein the diffuser plate has a light incident surface and a light emergent surface opposite to each other, the light incident surface of the diffuser plate is located between the light emergent surface of the diffuser plate and the second light source; the first light source includes a plurality of first light emitting elements; the second light source comprises a plurality of second light emitting elements; the first light-emitting element and the second light-emitting element are arranged in the diffusion plate, the first light spot is formed on the light-emitting surface of the light guide plate by the first light-emitting element, the second light spot is formed on the light-emitting surface of the diffusion plate by the second light-emitting element, the first light spot and the second light spot correspond to the same display area of the liquid crystal display panel, and the area of the first light spot is larger than that of the second light spot.

3. The display device of claim 1, wherein the at least one optical film comprises:

a first prism sheet arranged on the light emergent surface of the light guide plate and having a plurality of first prism structures; and

a second prism sheet arranged on the light emergent surface of the light guide plate and having multiple second prism structures, wherein the included angle between the extending direction of the multiple first prism structures and the extending direction of the multiple second prism structures is less than or equal to 30 °.

4. The display device of claim 3, wherein the at least one optical film further comprises:

a reflective polarized light brightness enhancement film arranged between the liquid crystal display panel and the second prism sheet.

5. The display device of claim 4, wherein the reflective polarizing brightness enhancement film has a plurality of protruding strip-shaped microstructures, and an included angle between an extending direction of the second prism structures and an extending direction of the strip-shaped microstructures is less than or equal to 30 °.

6. The display device of claim 1, wherein the at least one optical film comprises:

the inverse prism lens is arranged on the light-emitting surface of the light guide plate and is provided with a plurality of inverse prism structures.

7. The display device of claim 6, wherein the at least one optical film further comprises:

a reflection type polarized light brightness enhancement film arranged between the liquid crystal display panel and the inverse prism sheet.

8. The display device of claim 7, wherein the reflective polarizing brightness enhancement film has a plurality of protruding stripe-shaped microstructures, and an included angle between an extending direction of the inverse prism structures and an extending direction of the stripe-shaped microstructures is less than or equal to 30 °.

9. The display device as claimed in claim 1, wherein the light-emitting surface of the light guide plate has a plurality of protruding stripe-shaped microstructures, and an extending direction of the stripe-shaped microstructures of the light guide plate is substantially perpendicular to the light-incident surface of the light guide plate.

10. The display device according to claim 1, wherein the diffusion plate has a haze greater than that of the light guide plate.

11. The display device of claim 1, wherein the LCD panel has a first display area having the first gray scale value and a second display area having the second gray scale value larger than the first gray scale value; the first light source causes the first front brightness at a first position of the at least one optical film corresponding to the first display area, and the second light source causes the second front brightness at the first position of the at least one optical film corresponding to the first display area; the first light source causes the third front brightness at a second position of the at least one optical film corresponding to the second display area, and the second light source causes the fourth front brightness at the second position of the at least one optical film corresponding to the second display area.

12. The display device of claim 1, wherein a first illumination beam emitted by the first light source sequentially passes through the light incident surface of the light guide plate, the light emitting surface of the light guide plate, the at least one optical film and the liquid crystal display panel to form a first image beam; a second illumination beam emitted by the second light source sequentially passes through the diffusion plate, the bottom surface of the light guide plate, the light-emitting surface of the light guide plate, the at least one optical film and the liquid crystal display panel to form a second image beam; the first image beam has a first full width at half maximum in a direction, the second image beam has a second full width at half maximum in the direction, and the second full width at half maximum is larger than the first full width at half maximum.

13. The display device of claim 12, wherein the difference between the second full width at half maximum and the first full width at half maximum falls within a range of 10 ° to 70 °.