JP2004341099A - Luminescent display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a luminescent display device which realizes a uniform luminous display with sufficiently high luminance, can be thinned and can save power. <P>SOLUTION: A display panel 1 is composed of a transparent part 2 and a surrounding non-transparent part 3. A light guide plate 4 is provided on the rear side of the display panel 1, and a light source 5 is disposed in one side terminal of the light guide plate 4 and in a rear side area of the non-transparent part 3. Light L1 from the light source 5 is made incident to a side terminal of the light guide plate 4, and emitted to its upper surface while being propagated to be spread inside. Emitted light L2 is uniformly distributed over the entire surface of the display panel 1 and selectively permeates through the transparent part 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light-emitting display device applied to uses such as a light-emitting emblem incorporated in various devices, display panels, and the like.
[0002]
[Prior art]
2. Description of the Related Art In a light emitting display device, a light source such as an LED (Light Emitting Diode) or a CFL (Cathode Fluorescent Lamp) is arranged on the back of a display panel to emit a desired design such as a character or a figure formed transparently on the display panel. It is displayed. In the conventional device, there is a problem that the vicinity of the light source in the design portion looks extremely bright, and the appearance is deteriorated.
[0003]
Therefore, as means for improving the brightness non-uniformity, for example, a certain distance is provided between the display panel and the light source, or as disclosed in Patent Document 1, There is known a method in which a light from a light source is diffused by inserting a diffusion plate or the like into the device to make a transparent design portion emit light uniformly.
[0004]
Further, as a second means, by using a plurality of light sources such as LEDs and CFLs, the amount of light can be made uniform in a transparent design portion, or an electroluminescence (EL) element that emits light uniformly from the entire surface can be designed. It is conceived to arrange them entirely on the back side of the part.
[0005]
[Patent Document 1]
JP-A-7-234650
[Problems to be solved by the invention]
However, in the former method, it is difficult to reduce the thickness and increase the luminance, and there is a problem in practical use. In the latter case, there is a problem that power consumption is increased.
[0007]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a light-emitting display device that realizes sufficiently high-luminance and uniform light-emitting display, and that can be reduced in thickness and power consumption.
[0008]
[Means for Solving the Problems]
A light-emitting display device according to the present invention has a first region defining display contents and a second region surrounding the first region, and a visible light transmittance in the first region and the second region. And a light source that supplies light for display on the display plate, and a light source that is provided on the back side of the display plate and that transmits light from the light source to at least a region corresponding to the first region. And light guide means for emitting the propagated light so that the light emission luminance in at least the first region of the display panel is uniform.
[0009]
In the light emitting display of the present invention, the light incident on the light guide is propagated by the light guide and emitted to the display panel side with a uniform light amount. The light emitted by the emitted light has no unevenness in brightness.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0011]
FIG. 1 shows an application example of a light-emitting emblem according to an embodiment of the light-emitting display device of the present invention. The light-emitting emblem 10 is, for example, incorporated as a display panel in an arbitrary device or apparatus. Here, the light-emitting emblem 10 is incorporated in a housing 100 of a video display device such as a liquid crystal rear projector.
[0012]
FIG. 2 is a plan view illustrating a specific configuration of the light emitting emblem. 3 and 4 are a cross-sectional view (in the horizontal direction) along the line II and a cross-sectional view (in the vertical direction) along the line II-II. The light-emitting emblem 10 includes the display plate 1, the light guide plate 4, the light source 5, and an emblem folder (folder) 8 in which the mounting board 6 is accommodated. The display plate 1 is fitted into an opening provided in the housing 100 of the video display device, and a folder 8 is provided on the back side thereof. The folder 8 is supported and fixed to the housing 100. In the present embodiment, the folder 8 corresponds to a specific example of “housing” of the present invention.
[0013]
The display panel 1 is made of, for example, a transparent or slightly colored thin plate made of resin or glass. The front or back surface of the display panel 1 is partially coated by a printing method or the like, and the uncoated portion is the transparent portion 2 and the portion having the coating 3A by coating is the opaque portion 3. . The paint used for painting is not particularly limited, but for example, a synthetic resin ink is used. Here, the transparent portion 2 has a character shape, and is formed such that characters are arranged at regular intervals on the surface of the display panel 1. The shape of the transparent portion 2 is not limited to characters, and may be a desired display target such as various symbols, figures, and designs. Further, the opaque portion 3 is not limited to the one that completely blocks light, and may be a region having a lower light transmittance than the transparent portion 2.
[0014]
The light guide plate 4, the light source 5, and the mounting board 6 are accommodated inside (or part of) the folder 8, and these function as a backlight for illuminating the display panel 1 from the back. The light guide plate 4 takes in light from a side end portion and propagates the light into the layer, and is provided so as to face the back surface of the display plate 1. In this case, the light source 5 is disposed at one end of the light guide plate 4 and in a region behind the opaque portion 3. The light source 5 is, for example, a chip LED, is mounted on a mounting substrate 6, and is connected to an external power supply by a wiring 7. Although the light source 5 is composed of a plurality of chip LEDs, the number thereof may be adjusted according to the luminance and the light amount distribution on the display panel 1.
[0015]
FIG. 5 is an enlarged view of a main part of the light emitting emblem. As shown in the figure, when the light L1 from the light source 5 is incident on the side end, the light guide plate 4 propagates the light L1 into the layer and at the same time, almost uniformly the upper surface (of the display plate 1). Side surface). For this reason, the light guide plate 4 is provided with a distribution in thickness, or is optically processed on the upper surface, the lower surface, or both surfaces.
[0016]
6 and 7 both show specific examples of the light guide plate. (A) shows a side section, and (B) shows a plane. In the case of FIG. 6, a sawtooth-shaped groove 4A is formed on one surface of the light guide plate 4 to reflect or diffuse light. The shape such as the depth and angle of the groove 4A changes stepwise (continuously) in accordance with the distance from the light source 5 so that the amount of light to be reflected and diffused is uniform over the entire surface. The surface on which the grooves 4A are formed is inclined so that light is evenly applied to all the grooves 4A. Here, the thickness of the light guide plate 4 becomes thinner as the distance from the light source 5 increases. In FIG. 7, a hemispherical recess 4 </ b> B is formed on one surface of the light guide plate 4. The shape of the recess 4 </ b> B also changes stepwise (continuously) according to the distance from the light source 5.
[0017]
Although the above is an example in which the surface of the light guide plate 4 is processed to have a concave shape, such a sawtooth-shaped or dome-shaped projection may be provided on the surface. The depression 4B, the dome-shaped projection, and the like do not necessarily have to be a complete hemisphere. As described above, the surface shape of the light guide plate 4 may be any shape that acts to reflect and diffuse light in a predetermined direction, and may be a concave or convex surface such as a conical shape or a bale shape.
[0018]
Examples of the material of the light guide plate 4 include acrylic (PMMA), polycarbonate (PC), polystyrene (PS), styrene-acrylonitrile (SAN), polyester (PE), and cycloolefin (specifically, Zeonex, Zeonoa, etc., manufactured by Zeno Japan). ) And alicyclic polyolefins (specifically, Arton manufactured by JSR) can be used.
[0019]
Next, the operation or action of the light emitting emblem 10 will be described with reference to FIG.
[0020]
In the light emitting emblem 10, the power is supplied from the wiring 7 and the light source 5 emits light. At this time, the light L1 from the light source 5 propagates inside the light guide plate 4 and is emitted almost uniformly to the upper surface as emission light L2. The emitted light L2 is transmitted through the transparent portion 2 of the display panel 1, but is not transmitted through the opaque portion 3, so that the viewer 11 can visually recognize the light emission in the shape of the transparent portion 2. As described above, by converting the light L1 from the light source 5 into the light L2 that spreads uniformly over the entire display surface of the display panel 1, the display luminance distribution of the transparent portion 2 over the entire display surface is made uniform.
[0021]
Since the light source 5 is disposed on the back side of the opaque portion 3, light L1 does not substantially linearly reach the eyes of the viewer 11 through the transparent portion 2 as shown by the arrow α. 3 is prevented. In this way, by not injecting light directly from the light source 5 regarded as a point light source to the display panel 1 and indirectly injecting only the light L2 uniformly distributed on the display surface via the light guide plate 4, The brightness of the entire transparent portion 2 becomes substantially uniform, and a portion thereof is prevented from being extremely bright.
[0022]
As described above, the light-emitting emblem 10 of the present embodiment is configured to convert the light L1 from the light source 5 into the light L2 that is emitted almost uniformly to the entire display surface via the light guide plate 4. In addition, the display brightness in the transparent portion 2 can be made uniform. Further, since the light source 5 is disposed in the side end portion of the light guide plate 4 and in the region on the back side of the opaque portion 3, the light L1 is not directly displayed. As described above, even if the light source 5 is locally disposed with respect to the light guide plate 4, by making only the light L <b> 2 incident on the display plate 1, a part of the display on the transparent portion 2 may appear to be extremely bright. It can be prevented and the appearance can be improved.
[0023]
In addition, since light is given to the display panel 1 by using the light guide plate 4, a large display surface can be uniformly displayed with a small number of light sources, display efficiency is high, and power consumption is very low. Can be smaller.
[0024]
Further, in the light-emitting emblem 10, the backlight is of an edge light type in which the light source 5 is provided at the side end of the light guide plate 4, so that the distance between the light source and the display plate is not required as in the related art, and the thickness is reduced. can do.
[0025]
[Modification]
Next, a modified example of the above embodiment will be described. In the following modifications, the same components as those in the embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
[0026]
(Modification 1)
FIG. 8 is an enlarged configuration diagram of a main part of a light-emitting emblem according to a first modification of the embodiment. The emblem folder (folder) 18 in this case has an optical effect applied to the bottom surface, that is, the surface in contact with the light guide plate 4. Specifically, a reflection layer 18 </ b> A for increasing the reflectance with respect to light from the light guide plate 4 is formed on the bottom portion of the folder 18. The reflection layer 18A is formed by a so-called silver color process by plating, vapor deposition, or the like. The reflection layer 18A is formed separately from the folder 18 or prepared in a film state, in addition to being formed on the bottom surface of the housing 18 using surface processing or the like. Alternatively, the information may be attached to the folder 18. Further, it may be formed integrally with the folder 18.
[0027]
When the light L1 propagates inside the light guide plate 4, a transmission component β to the folder 18 side is generated. On the bottom surface of the folder 18, as shown by the arrow γ, the reflection layer 18A reflects the transmission component β and acts to reduce optical loss due to propagation. Therefore, according to this modification, more efficient light-emitting display can be performed.
[0028]
In this case, when the external light L3 is irradiated from the outside of the display panel 1, as shown by an arrow δ, the external light L3 transmitted through the transparent portion 2 is reflected by the reflective layer 18A. You. On the other hand, the part of the external light L3 which is irradiated on the opaque part 3 is absorbed by the coating film 3A. For this reason, since the transparent portion 2 itself appears to be emitting light to the viewer 11, even if the light source 5 is not emitting light, the display panel 1 performs display using the external light L3. Is possible.
[0029]
(Modification 2)
In the first modification, the reflection layer 18A is provided on the bottom surface of the folder 18. However, in addition to positively adding the reflection function, an optical effect of preventing transmission and absorption of light is provided. In this case, the effect of the first modification can be obtained. That is, in this modified example, as shown in FIG. 9, the emblem folder (folder) 28 is formed of a white material, for example, a white pigment or paint, in order to suppress the transmission and absorption of light on the bottom surface 28A (the surface in contact with the light guide plate 4). Is formed of a synthetic resin or the like in which is mixed. Note that the folder 28 may be one in which a white paint is applied to the bottom surface 28A. That is, here, the folder 28 corresponds to a specific example of “transmission absorption preventing means” in the present invention.
[0030]
When the light L1 propagates through the inside of the light guide plate 4, a transmission component β is generated on the side of the housing 28. Here, since the transmission absorptance of the bottom surface 28A is low, the transmission component β is The rate of reflection rather than transmission and absorption at 28A is higher. Thus, optical loss generated during propagation of the light guide plate 4 is reduced, and light emission display can be performed more efficiently than in the above embodiment.
[0031]
Note that the present invention is not limited to the above-described embodiment and modified examples, and various modified embodiments are possible. For example, as the light source, a bullet-type LED or a thin LED may be used instead of the chip type. In the latter case, the thickness of the light guide plate can be reduced, and the thickness of the light emitting display device can be reduced. The number of LEDs is not particularly limited. By arranging a plurality of LEDs at one end or two or more directions at the side end of the light guide plate, the brightness is increased or the light amount is uniformly distributed. May be adjusted as follows. Further, the voltage applied to the LED may be adjustable, and the luminance of the LED may be changed by increasing or decreasing the voltage. Moreover, you may make it blink an LED periodically. Further, as the light source, a light emitting element other than the LED, such as a CFL, may be used, and a light emitting element of any color or a multicolor light emitting element can be selected.
[0032]
Further, in the above embodiment, the transparent portion 2 and the opaque portion 3 are formed by applying the coating film 3A to the display panel 1, but in the present invention, the display panel is formed by another method. A non-light-transmitting part and a light-transmitting part may be provided. For example, a light-transmitting substrate or a non-light-transmitting substrate which is a separate resin sheet or molded product may be combined. Further, the non-light-transmitting portion and the light-transmitting portion may be formed by a two-color molding method.
[0033]
In addition, in the first modification, the folder 18 has the reflecting ability by providing the reflective layer 18A on the bottom surface, but such a folder itself may be formed of a reflective material. Further, the reflecting means in the present invention may be arranged on the side opposite to the side facing the display plate with respect to the light guiding means, and need not necessarily be provided integrally with the folder. The formation of the reflective layer by silver color processing has a great practical advantage that a reflective layer (reflecting means) that widely reflects light in the visible region can be easily formed. It is also possible to design in consideration of the optical properties of the light guide plate.
[0034]
In the second modification, the folder 28 is formed of the transmission and absorption preventing material. However, a function may be added to the housing by, for example, providing a transmission and absorption preventing layer on the bottom surface. Further, the transmission / absorption prevention means in the present invention may be disposed on the opposite side of the light guide means from the side facing the display panel, and may have a low transmittance or absorptivity to light from the light guide means. . Therefore, the configuration is not limited to be provided integrally with the folder (housing). The transmission / absorption prevention means can also be designed as a so-called optical multilayer film while taking into account, for example, the optical properties of the light guide plate. Further, in the first and second modifications, a specific example of the reflection unit and the transmission / absorption prevention unit has been described. However, the light emitting display device may have both functions by using, for example, an optical multilayer film. Good.
[0035]
Further, the light emitting display device of the present invention is not limited to a relatively small one such as an emblem, and can have a desired size. In the case of increasing the size of the display surface, for example, the number of light sources is increased, a plurality of light sources are arranged at a plurality of places such as both end portions of the light guide plate, or a light source having a large light emitting area such as a CFL is used. In this case, sufficient brightness can be ensured. Further, in order to improve light emission luminance and light emission uniformity in the light transmitting portion, a light diffusion sheet, a prism sheet, or the like may be disposed between the display panel and the light guide layer. As described above, the light-emitting display device of the present invention does not need to have a configuration in which the light from the light guide plate 4 is directly applied to the back surface of the display plate 1 as described in the embodiment.
[0036]
The light-emitting display device according to the present invention has a configuration in which it is housed in a housing and is an independent device that exclusively performs a display function, a configuration in which components having other functions are built-in, and conversely, electronic devices and vehicle components. It may be configured so as to be integrated integrally with the like.
[0037]
Further, the light guide means in the present invention is not limited to a plate-like form which is disposed opposite to the back surface of the display panel 1 like the light guide plate 4 in the above embodiment. (2) At least in the light-emitting display area, the light-emitting element should be capable of emitting light with a uniform light amount distribution. Since the light-emitting emblem described in the embodiment is relatively small, it is considered that the light guide plate 4 that emits light to the entire display surface has many advantages because the configuration and the manufacturing process are simpler. When the screen is large, or when it is desired to reduce power loss even on a small display screen as much as possible, the light guide plate may be selectively arranged in a region corresponding to the first region for determining display contents on the display surface. Alternatively, an optical fiber or the like may be appropriately used as the light guide.
[0038]
【The invention's effect】
As described above, according to the light emitting display device of the present invention, the light incident from the light source is provided on the rear side of the display panel and propagated to at least a region corresponding to the first region, and the propagated light is And light guide means for emitting light so as to make the light emission luminance uniform in at least the first region of the display panel, so that light from the light source propagates inside the light guide means and at least the first light guide means. The light is emitted so that the light amount distribution in the region becomes uniform. Therefore, the display brightness is made uniform regardless of the number and arrangement of the light sources, and the appearance can be improved. In addition, since the light from the light source is propagated through the light guide means, a large display surface can be uniformly displayed with a small number of light sources, thereby improving display efficiency and reducing power consumption. . Furthermore, since the light source is of the edge light type provided at the side end of the light guide means, the distance between the light source and the display panel is not required as in the related art, and the thickness can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an application mode of a light emitting display device according to an embodiment of the present invention.
FIG. 2 is a plan view showing a configuration of the light emitting display device shown in FIG.
FIG. 3 is a cross-sectional view of the light emitting display device shown in FIG.
FIG. 4 is a cross-sectional view of the light emitting display device shown in FIG. 1, taken along the line II-II.
5 is a cross-sectional view illustrating a configuration of a main part of the light emitting display device illustrated in FIG.
FIG. 6 is a cross-sectional view illustrating a specific example of the light guide plate illustrated in FIG.
FIG. 7 is a cross-sectional view illustrating another specific example of the light guide plate illustrated in FIG.
FIG. 8 is a diagram illustrating a main configuration of a light emitting display device according to a modification of the light emitting display device illustrated in FIG. 2;
FIG. 9 is a diagram illustrating a main configuration of a light emitting display according to a modification of the light emitting display illustrated in FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Display board, 2 ... Transparent part, 3 ... Opaque part, 3A ... Coating, 4 ... Light guide plate, 5 ... Light source, 6 ... Mounting board, 7 ... Wiring, 8, 18, 28 ... Emblem folder (folder), Reference Signs List 10: light-emitting emblem, 11: viewer, 18A: reflective layer, 28A: folder surface, 100: housing of video display device, L1: light from light source, L2: light emitted from light guide plate, L3 ... External light.

Claims (10)

It has a first area defining display content and a second area surrounding the first area, and performs display based on a difference in visible light transmittance between the first area and the second area. A display board,
A light source for supplying light for display on the display panel,
The light-emitting device is provided on the back side of the display panel, and transmits incident light from the light source to at least a region corresponding to the first region, and emits the propagated light in at least a first region of the display plate. A light guide means for emitting light so as to make the luminance uniform, a light emitting display device. The light guide means is a light guide plate attached to the back surface of the display panel, and emits a plane from one surface while propagating incident light from a side end surface inside,
The light emitting display device according to claim 1, wherein the light source is disposed near a side end surface of the light guide plate. The light emitting display device according to claim 1, wherein the light source is disposed in a region other than a region through which visible light is transmitted to the display plate, on a rear side of the display plate. The first region is a light-transmitting portion through which visible light can pass, the second region is a non-light-transmitting portion through which visible light cannot pass, and the light source is other than the light-transmitting portion on the rear surface of the display panel. The light emitting display device according to claim 3, wherein the light emitting display device is provided at a position facing the region. The light emitting display device according to claim 4, wherein the display panel has a non-light-transmitting portion and a light-transmitting portion formed by forming a coating film on a light-transmitting substrate. The light emitting display device according to claim 4, wherein the display panel has a non-light-transmitting portion and a light-transmitting portion formed by combining a light-transmitting substrate and a non-light-transmitting substrate. 2. The light-emitting display device according to claim 1, wherein a reflection unit that reflects the irradiated light is provided on a side of the light guide unit opposite to a side facing the display plate. 8. The light-emitting device according to claim 7, wherein one surface is open, the display plate is disposed in the opening, the light guide is accommodated therein, and at least a part of the housing has a reflecting ability. The light-emitting display device according to claim 1. 2. The transmission / absorption prevention means for preventing at least one of transmission and absorption of light is provided on a side of the light guide means opposite to a side facing the display plate. Light-emitting display device. One surface is open, the display plate is disposed in the opening portion, the light guide means is accommodated inside, and at least a part of the housing has a function as the transmission and absorption prevention means. The light emitting display device according to claim 9, wherein

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