JP2014071343A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device which maintains a preferable value of incidence efficiency of light made incident on a light guide plate from a light source and reduces light leaked from the light guide plate even when the light guide plate is expanded.SOLUTION: A liquid crystal display device comprises: a liquid crystal panel 1 displaying an image on a front side; a rectangular substrate 31 having a plurality of light emission elements 30 mounted thereon; and a light guide plate 2 provided on a rear side of the liquid crystal panel 1, and emitting light of the plurality of light emission elements 30 made incident from a side surface of the light guide plate to a rear side direction of the liquid crystal panel 1 to irradiate the liquid crystal panel 1. On the side surface of the light guide plate 2 on which the light of the plurality of light emission elements 30 is made incident is provided a recessed part 21 for accommodating the plurality of light emission elements, and a part 22 on which the recessed part 21 is not provided on the side surface of the light guide plate 2 is configured to contact with a light emission element mounting surface of the substrate 31.

Description

  The present invention relates to an edge light type liquid crystal display device.

  A liquid crystal display device including a liquid crystal panel as a display panel is thin and lightweight and consumes little power. Therefore, in recent years, it has been widely adopted as an image display device for television receivers, computers, and portable terminals.

  The liquid crystal panel, which is a constituent member of the liquid crystal display device, does not emit light by itself. Therefore, unlike a display device using a self-luminous element such as an organic EL (electroluminescence), the liquid crystal display device requires a light source section having a surface for applying light to the entire back surface of the liquid crystal panel.

  One of the light source units is an edge light type light source unit. In the edge light system, a light guide plate and a cover that supports the light guide plate are arranged on the back side of the liquid crystal panel, and a light source is arranged on the side surface side of the light guide plate. In the edge light system, light incident from the side surface of the light guide plate is diffused in the light guide plate and emitted from one surface of the light guide plate. The emitted light is irradiated on the entire back surface of the liquid crystal panel.

  In such an edge light system, the positional relationship between the light source and the light guide plate is an important factor related to quality. When the distance between the light source and the light guide plate is too wide, the amount of light incident on the light guide plate from the light source becomes insufficient, resulting in a problem of a decrease in luminance. Moreover, when the space | interval of a light source and a light-guide plate is uneven, the problem that the nonuniformity of a brightness | luminance generate | occur | produces arises. Therefore, it is necessary to assemble the light source and the light guide plate so that the distance between the light source and the light guide plate is within a predetermined dimension.

  With respect to assembling the light source and the light guide plate so that the distance between the light source and the light guide plate is within a predetermined dimension, Patent Document 1 forms protrusions at both ends of the light incident surface of the light guide plate, A liquid crystal display device is described in which a light guide plate is positioned by a configuration in which a protruding portion is in contact with a mounting substrate of a light source via a cushion material.

JP 2008-298905 A

  However, in the liquid crystal display device described in Patent Document 1, the light guide plate is positioned at both ends in the longitudinal direction of the light guide plate. The light guide plate and the mounting substrate are in contact with each other only at two locations on both ends in the longitudinal direction. Therefore, when the light guide plate expands due to heat generated by the light source, there arises a problem that the distance between the light source and the light guide plate is likely to be uneven depending on the location. In addition, since the end face of the light guide plate facing the light source is a flat surface, there is a problem that the incident efficiency of light incident from the light source to the light guide plate is poor.

  The present invention has been made in view of the circumstances as described above, and maintains the incident efficiency of light incident from the light source to the light guide plate at a good value even when the light guide plate is expanded. An object of the present invention is to provide a liquid crystal display device with reduced light leaking from the liquid crystal display.

  The liquid crystal display device according to the present invention includes a liquid crystal panel that displays an image on the front side, a rectangular substrate on which a plurality of light emitting elements are mounted, and a plurality of the plurality of light incident on a side surface of the liquid crystal panel. In a liquid crystal display device including a light guide plate that emits light of the light emitting element toward the back side of the liquid crystal panel and irradiates the liquid crystal panel, a side surface of the light guide plate on which light of the plurality of light emitting elements is incident is A concave portion for accommodating a plurality of light emitting elements is provided, and a portion of the side surface of the light guide plate not provided with the concave portion is in contact with the light emitting element mounting surface of the substrate.

  The liquid crystal display device according to the present invention is characterized in that the recess is a groove provided along the longitudinal direction of the side surface of the light guide plate.

  The liquid crystal display device according to the present invention is characterized in that a plurality of the recesses are provided apart in the longitudinal direction of the side surface of the light guide plate.

  The liquid crystal display device according to the present invention is characterized in that the bottom surface of the recess is a curved surface.

  The liquid crystal display device according to the present invention is characterized in that a reflective material is provided on a side wall surface of the recess.

  In the liquid crystal display device according to the present invention, the reflective material is a reflective tape or a reflective paint.

  A television receiver according to the present invention includes any one of the liquid crystal display devices described above and a tuner unit that receives a television broadcast, and an image relating to the television broadcast received by the tuner unit is displayed on the liquid crystal display. It is characterized by being displayed on the apparatus.

  In the present invention, the side surface of the light guide plate on which light from a plurality of light emitting elements is incident is provided with a recess for housing the plurality of light emitting elements, and the portion of the side surface of the light guide plate that is not provided with the recess is Since the light-emitting element mounting surface of the substrate is in contact with the light-emitting element, the distance between the light-emitting element and the light guide plate can be kept constant, and the incident efficiency of light incident on the light guide plate can be kept at a good value. .

1 is a perspective view illustrating an appearance of a liquid crystal television in a first embodiment. It is a longitudinal cross-sectional view which shows the principal part of a liquid crystal television. It is a fragmentary perspective view of a light source module. It is a perspective view of a light-guide plate. It is explanatory drawing which shows the positional relationship of a light source module and a light-guide plate. It is explanatory drawing which shows the positional relationship of the light source module which concerns on Embodiment 2, and a light-guide plate. 6 is a perspective view of a light guide plate according to Embodiment 3. FIG.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. Here, a liquid crystal television receiver (hereinafter referred to as “liquid crystal television”) including a liquid crystal display device as an image display unit is taken as an example.

Embodiment 1
FIG. 1 is a perspective view showing the appearance of the liquid crystal television in the first embodiment. The liquid crystal television includes a liquid crystal panel 1, an appearance frame 10, a rear cabinet 11, a stand 15, a tuner unit 12, an image processing unit 13, and a power supply control unit 14. The liquid crystal panel 1 has a substantially rectangular parallelepiped shape and displays an image on the front side. The appearance frame 10 is a rectangular frame and covers the periphery of the liquid crystal panel 1 from the front side. The rear cabinet 11 covers the back side of the liquid crystal panel 1. The stand 15 is for placing the liquid crystal television on a flat surface such as a table.

In the following description, in the vertical posture in which the liquid crystal television is installed by the stand 15, the direction from the liquid crystal panel 1 to the stand 15 side is referred to as the lower side, and the opposite direction is referred to as the upper side.
In the description of each component of the liquid crystal television, the direction in which each component is assembled is described.

  FIG. 2 is a longitudinal sectional view showing a main part of the liquid crystal television. The liquid crystal television according to the present embodiment is obtained by laminating a reflection sheet 8, a light guide plate 2, an optical sheet 7, and a liquid crystal panel 1 on a plate-like backlight chassis 9. At the lower part of the liquid crystal television, there is a heat radiating plate 4 having an inverted L-shaped cross section whose one surface is fixed to the backlight chassis 9 and whose other surface rises perpendicularly to the backlight chassis 9. The light source module 3 on which the light emitting element 30 is mounted is fixed to the other surface of the heat radiating plate 4 so as to face the side surface of the light guide plate 2. The light source module 3 is fixed to the heat sink 4 with double-sided tape.

  The light emitting element 30 is accommodated in the recess 21 provided on the side surface of the light guide plate 2. The portion of the side surface of the light guide plate 2 where the recess 21 is not provided is in contact with the light emitting element 30 mounting surface of the light source module 3. A reflective material 2 a is provided on the side wall surface of the recess 21. The reflective material 2a has a reflective tape attached thereto. Alternatively, a reflective paint may be applied.

  The panel cover 5 holds the liquid crystal panel 1 and the light guide plate 2 from the front side through an elastic member 6a, and is fixed by a rear cabinet 11 and screws 11a that cover the back side of the backlight chassis 9 at the bottom of the liquid crystal television.

  A front cabinet 6 is fixed to the rear cabinet 11 so as to cover the front side of the panel guide 5. On the front side of the front cabinet 6, an external frame 10 is further arranged. The external frame 10 is fixed to the front cabinet 6 with double-sided tape or the like. The front cabinet 6 and the external frame 10 are made of resin. The appearance frame 10 may be made of metal to give a high-class feeling.

  The front cabinet 6 and the rear cabinet 11 are fixed by, for example, engaging a locking claw provided on the rear cabinet 11 and an engaging portion provided on the front cabinet 6. Alternatively, it is performed by screwing a boss provided in the front cabinet 6 and a screw inserted into a screw hole provided in the rear cabinet 11.

  In the liquid crystal television configured as described above, the light emitted from the light emitting element 30 enters from the concave portion 21 provided on the side surface of the light guide plate 2. Since there is a reflection sheet 8 on the back side of the light guide plate 2, the light traveling in the back side direction of the light guide plate 2 is reflected by the reflection sheet 8. The light reflected by the reflection sheet 8 is emitted from the front side of the light guide plate 2 and irradiates the liquid crystal panel 1 from the back side. The liquid crystal panel 1 is controlled, and an image is displayed on the front side of the liquid crystal panel 1.

  The backlight chassis 9 is formed of a metal plate, for example, a steel plate. The backlight chassis 9 covers the liquid crystal panel 1, the light guide plate 2, the light source module 3 and the like from the back side of the liquid crystal television.

  The reflection sheet 8 has substantially the same shape as the light guide plate 2 in plan view. The reflection sheet 8 is a synthetic resin sheet. The reflection sheet 8 has a function of totally reflecting incident light.

  The light guide plate 2 has a rectangular plate shape that is slightly smaller than the backlight chassis 9. The light guide plate 2 is made of a synthetic resin such as acrylic resin, polycarbonate resin, methacrylic resin, or cyclic polyolefin.

  The optical sheet 7 includes a plurality of sheets. The plurality of sheets constituting the optical sheet 7 are a diffusion sheet, a reflective polarizing sheet, a lens sheet, and the like. The optical sheet 7 is a synthetic resin sheet. The optical sheet 7 is a laminated body in which these plural sheets are laminated.

  The liquid crystal panel 1 has a substantially rectangular parallelepiped shape, and displays an image on the front side (front side).

  The heat sink 4 is a member having an L-shaped cross section. The heat radiating plate 4 is a rod-shaped member provided along the longitudinal direction of the side surface of the light guide plate 2. The heat radiating plate 4 includes a surface parallel to the side surface (lower end surface) of the light guide plate 2 and a surface continuous with the surface parallel to the back surface of the liquid crystal panel 1. The light source module 3 is fixed to a surface parallel to the lower end surface of the light guide plate 2 of the heat radiating plate 4. A surface parallel to the back surface of the liquid crystal panel 1 of the heat radiating plate 4 is fixed to the backlight chassis 9. The heat sink 4 plays a role of radiating heat generated in the light emitting element 30. The heat radiating plate 4 is formed of a material having high thermal conductivity, for example, aluminum.

  The panel guide 5 is made of metal to ensure strength. An elastic member 6a is provided at a portion where the panel guide 5 and the liquid crystal panel 1 are in contact and a portion where the panel guide 5 and the light guide plate 2 are in contact. The elastic member 6 a securely fixes the liquid crystal panel 1 and the light guide plate 2 and prevents the liquid crystal panel 1 and the light guide plate 2 from being damaged by the panel guide 5.

  The rear cabinet 11 has a box shape. The back side of the backlight chassis 9, the light guide plate 2, and the side edges of the liquid crystal panel 1 are covered. The rear cabinet 11 is made of resin.

  The tuner unit 12 receives a television broadcast and extracts a broadcast signal. The image processing unit 13 extracts image information from the broadcast signal. An image is displayed on the liquid crystal panel 1 based on the extracted image information. The power supply control unit 14 supplies power of a predetermined voltage to each unit of the liquid crystal television.

  The liquid crystal television according to the present embodiment is assembled as follows. First, the reflection sheet 8, the light guide plate 2, the optical sheet 7, and the liquid crystal panel 1 are stacked on the backlight chassis 9. Further, the heat radiating plate 4 to which the light source module 3 is fixed with a double-sided tape is disposed in the backlight chassis 9. The tuner unit 12, the image processing unit 13, and the power supply control unit 14 are fixed to the backlight chassis 9. The rear cabinet 11 is put on the backlight chassis 9, and the panel cover 5 and the backlight chassis 9 are fixed with screws 11a. Further, the front cabinet 6 and the rear cabinet 11 are fixed to each other. Further, the external frame 10 is fixed to the panel cover 6 from the front side of the front cabinet 6 with a double-sided tape or an adhesive.

  FIG. 3 is a partial perspective view of the light source module 3. As illustrated in FIG. 3, the light source module 3 includes a plurality of light emitting elements 30, a flat rectangular shape on which the light emitting elements 30 are mounted, and includes a strip-shaped substrate 31 and a connector 32. The substrate 31 is formed of a material having good thermal conductivity such as aluminum. The light emitting elements 30 are LEDs (Light Emitting Diodes) and are juxtaposed at predetermined intervals along the longitudinal direction of the substrate 31. The light emitting element 30 is driven by a drive circuit (not shown) to emit light. The drive current of the light emitting element 30 is supplied by a cable connected to the connector 32. The connector 32 is provided at one end of the substrate 31. The liquid crystal television according to the present embodiment includes two light source modules 3. It is the light source module 3 shown in FIG. 3, and the light source module 3 symmetrical to it.

  FIG. 4 is a perspective view of the light guide plate 2. The light guide plate 2 has a rectangular plate shape. A recess 21 is provided on the side surface of the light guide plate 2. The illustrated recess 21 is a groove provided along the longitudinal direction of the side surface of the light guide plate 2. The cross section of the recess 21 is U-shaped.

  FIG. 5 is an explanatory diagram showing the positional relationship between the light source module 3 and the light guide plate 2. The light emitting element 30 mounted on the light source module 3 is accommodated in a recess 21 formed in the light guide plate 2. The recess 21 surrounds the front and rear of the light emitting element 30. A portion 22 where the concave portion 21 is not provided on the side surface of the light guide plate 2 is in contact with the light emitting element 30 mounting surface of the substrate 31 of the light source module 3. A reflective tape 2a is attached to the side wall surface of the recess 21 along the longitudinal direction.

  The light of the light emitting element 30 enters the bottom surface of the recess 21. The light of the light emitting element 30 that does not directly enter the recess 21 is reflected by the reflective tape 2 a and enters the bottom surface of the recess 21.

  A portion 22 where the concave portion 21 is not provided on the side surface of the light guide plate 2 is in contact with the mounting surface of the light emitting element 30. Thereby, the position of the light guide plate 2 with respect to the light source module 3 can be determined so that the distance between the light incident surface which is the bottom surface of the recess 21 and the light emitting element 30 is a predetermined distance. The portion 22 where the concave portion 21 is not provided extends along the longitudinal direction and is in contact with the light emitting element 30 mounting surface. Therefore, even when the light guide plate 2 expands and contracts, it is possible to minimize the variation in the distance between the light incident surface of the light guide plate 2 and the light emitting element 30 in the longitudinal direction of the light source module 3. Become.

  Further, by applying the reflective tape 2 a to the side wall surface of the recess 21, it is possible to reflect light that is about to leak out of the light guide plate 2 and to enter the light guide plate 2. Thereby, light leakage can be prevented and the incident efficiency of light incident on the light guide plate 2 can be increased.

Embodiment 2
In Embodiment 1, although the cross section of the recessed part 21 provided in the light-guide plate 2 was made into U shape, it is not limited to it. FIG. 6 is an explanatory diagram showing the positional relationship between the light source module 3 and the light guide plate 2 according to the second embodiment. The recess 21 has a rectangular cross section. The difference between the first embodiment and the second embodiment is the cross-sectional shape of the recess 21. Description of other parts similar to those of the first embodiment is omitted.

  Also in the second embodiment, the same effects as in the first embodiment described above are obtained. In addition, the shape of the recess 21 may be selected in accordance with the spread angle of light emitted from the light emitting element 30 and a shape that increases the incident efficiency. For example, when the spread angle is large, it is considered that the U shape is more suitable than the rectangular shape. When the spread angle is small, it is considered that a rectangular shape is more suitable than a U-shape.

Embodiment 3
FIG. 7 is a perspective view of the light guide plate 2 according to the third embodiment. In the first embodiment, the concave portion 21 provided on the side surface of the light guide plate 2 is a single groove that is uniform along the longitudinal direction. However, the present invention is not limited to this. A plurality of recesses 21 may be provided intermittently corresponding to the position of the light emitting element 30. The difference between the first embodiment and the third embodiment is whether the recess 21 is a uniform groove or a plurality of intermittent grooves. Description of other parts similar to those of the first embodiment is omitted.

  In the third embodiment, the concave portion 21 has a U-shaped side section. A plurality of the recesses 21 are provided apart from each other along the longitudinal direction of the side surface of the light guide plate 2. The recess 21 accommodates the light emitting element 30 mounted on the light source module 3. Therefore, the recess 21 may be formed in accordance with the position of the light emitting element 30. The side cross section of the recess 21 is U-shaped as in the first embodiment. The bottom surface facing the longitudinal direction of the recess 21 is a flat surface. A reflective tape is affixed to the side wall surface of the recess 21 other than the light incident surface.

  Also in the third embodiment, the same effects as in the first embodiment described above are obtained. In addition, in the third embodiment, since the four side surfaces of the light emitting element 30 are covered with the recesses 21, it is possible to further reduce the amount of light leaking and increase the light incident on the light guide plate 2. It becomes possible.

  In the third embodiment, the concave section 21 has a U-shaped side section, but is not limited thereto. A rectangular shape may be used as in the second embodiment. Further, the bottom surface of the recess 21 may be a three-dimensional curved surface whose side cross section is not U-shaped.

  In addition, although the reflective tape can be applied to the side wall surface of the recess 21, a reflective paint may be applied instead of the reflective tape.

  It should be understood that the above-described embodiment is illustrative in all respects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 Light guide plate 21 Recessed part 2a Reflective material 3 Light source module 30 Light emitting element 31 Board | substrate 4 Heat sink 5 Panel guide 6 Front cabinet 7 Optical sheet 8 Reflective sheet 9 Backlight chassis 10 External frame 11 Rear cabinet 12 Tuner part 13 Image processing Part 14 Power supply control part

Claims (5)

A liquid crystal panel that displays an image on the front side, a rectangular substrate on which a plurality of light emitting elements are mounted, and a light source of the plurality of light emitting elements that is arranged on the back side of the liquid crystal panel and is incident from a side surface of the liquid crystal panel In a liquid crystal display device comprising a light guide plate that emits in the rear side direction and irradiates the liquid crystal panel,
On the side surface of the light guide plate on which the light of the plurality of light emitting elements is incident, there are provided recesses for accommodating the plurality of light emitting elements,
A portion of the side surface of the light guide plate that is not provided with the concave portion is in contact with the light emitting element mounting surface of the substrate. The liquid crystal display device according to claim 1, wherein the concave portion is a groove provided along a longitudinal direction of a side surface of the light guide plate. The liquid crystal display device according to claim 1, wherein a plurality of the recesses are provided apart from each other in the longitudinal direction of the side surface of the light guide plate. The liquid crystal display device according to any one of claims 1 to 3, wherein a bottom surface of the concave portion is a curved surface. The liquid crystal display device according to any one of claims 1 to 4, wherein a reflective material is provided on a side wall surface of the recess.

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