JP7267830B2 - Display device - Google Patents

Description

The present invention relates to a display device having a direct type backlight.

2. Description of the Related Art Conventionally, there has been known a display device provided with a direct type backlight in which a plurality of light sources (LEDs) are arranged on the back side of a display panel. In addition, in a display device equipped with a direct type backlight, a support member (support pin) that supports the diffusion plate from the back side is arranged between the light sources in order to suppress the deformation of the diffusion plate arranged facing the light source. A technique for doing so has been proposed (see Patent Document 1, for example).

JP 2014-13690 A

However, in the above-described conventional technology, when the number of light sources is reduced or the display device and backlight are thinned, a shadow appears in the region (directly above) corresponding to the position of the support member on the display screen, resulting in uneven brightness. A problem arises. In the future, it is expected that the problem of luminance unevenness will become more pronounced due to the reduction in the number of light sources and the reduction in the thickness of display devices accompanying improvements in LED performance.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a display device having a direct type backlight capable of suppressing luminance unevenness on a display screen caused by a support member that supports a diffusion plate.

A display device according to one aspect of the present invention includes a light source arranged on the back side of a display panel, a diffusion plate arranged to face the light source, and the diffusion plate supported from the back side of the diffusion plate. A support member, and a backlight chassis that accommodates the light source, the diffusion plate, and the support member, and the support member includes a translucent portion that transmits light emitted from the light source, and a vicinity of the diffusion plate. and a diffusing portion disposed in the light source for diffusing and emitting the light incident from the light source to the outside.

According to the present invention, it is possible to suppress luminance unevenness on the display screen caused by the support member that supports the diffusion plate.

FIG. 1 is an exploded perspective view showing the overall configuration of a display device according to an embodiment of the invention. FIG. 2 is a cross-sectional view showing the configuration of the display device according to the embodiment of the invention. FIG. 3 is a plan view showing arrangement positions of light sources and support members in the display device according to the embodiment of the present invention. FIG. 4 is a perspective view showing the configuration of the support member in the display device according to the embodiment of the invention. FIG. 5 is a side view showing the configuration of part of the display device according to the embodiment of the invention. FIG. 6 is a diagram showing how light propagates in the display device according to the embodiment of the present invention. FIG. 7 is a side view showing the configuration of part of the display device according to the embodiment of the invention. FIG. 8A is a side view showing the configuration of the diffusing section according to the first embodiment of the present invention; FIG. 8B is a front view showing the configuration of the diffusing section according to the first embodiment of the present invention; FIG. 9A is a side view showing the configuration of a diffusion section according to Example 2 of the present invention. FIG. 9B is a front view showing the configuration of the diffusion section according to Example 2 of the present invention. FIG. 10A is a side view showing the configuration of a diffusion section according to Example 3 of the present invention. FIG. 10B is a front view showing the configuration of a diffusion section according to Example 3 of the present invention. FIG. 11A is a side view showing the configuration of a diffusion section according to Example 4 of the present invention. FIG. 11B is a front view showing the configuration of a diffusion section according to Example 4 of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the following embodiment is an example that embodies the present invention, and does not have the character of limiting the technical scope of the present invention.

The display device of the present invention is a display device provided with a direct backlight in which a plurality of light sources (LEDs) are arranged on the back side of the display panel. FIG. 1 is an exploded perspective view showing the overall configuration of a display device 1 according to an embodiment of the invention. FIG. 2 is a cross-sectional view showing the configuration of the display device 1. As shown in FIG.

Schematically, the display device 1 includes a display panel 100 that displays an image in a display area, a backlight 200 arranged on the back side of the display panel 100, and a display panel 100 and the backlight 200 that surround the display panel 100 and the backlight 200. and a bezel 300 forming an outer frame of the device 1 .

The display panel 100 is, for example, a liquid crystal panel. Note that the display panel 100 is not limited to a liquid crystal panel, and may be a signboard using the backlight 200 . Further, the present invention may be a lighting device or the like that does not include the display panel 100 but includes the backlight 200 . When the display panel 100 is, for example, a liquid crystal panel, the display panel 100 includes a plurality of data signal lines (source lines) extending in the first direction (column direction) and a plurality of data signal lines (source lines) extending in the second direction (row direction). gate signal lines (scanning signal lines), data signal lines, a plurality of thin film transistors (TFTs), pixel electrodes, common electrodes (common electrodes), liquid crystal layers, etc. not shown). A known technique can be applied to the display panel 100 . The display device 1 may include a touch panel (not shown) arranged in front of the display panel 100 .

The backlight 200 includes optical sheets 61 and 62 arranged on the back side of the display panel 100, a diffusion plate 50 arranged on the back side of the optical sheets 61 and 62, and a plurality of backlights arranged on the back side of the diffusion plate 50. light sources 20 (LEDs), a plurality of support members 30 that support the diffusion plate 50 from the rear side, and a backlight chassis 10 that accommodates these constituent members. The backlight chassis 10 includes a back plate and side plates rising from the periphery of the back plate to form an internal space. The light source 20 and the support member 30 are arranged on the inner surface of the inner space of the backlight chassis 10 . A reflective sheet 40 is arranged on the inner surface of the backlight chassis 10 . An LED is an example of the light source of the present invention.

The light source 20 and the support member 30 are fixed to the backlight chassis 10 respectively. For example, the light source 20 is arranged on a substrate 21, and the substrate 21 is fixed to the inner surface of the backlight chassis 10 by means of mounting members (screws, adhesive tape, etc.). The support member 30 is adhesively fixed to the inner surface of the backlight chassis 10 by an adhesive layer (adhesive tape or the like) formed on the back surface of the support member 30 .

An opening 41 is formed in the reflection sheet 40 at a position corresponding to the position where the light source 20 is arranged on the backlight chassis 10 . Similarly, the reflection sheet 40 is formed with an opening 42 at a position corresponding to the position where the support member 30 is arranged on the backlight chassis 10 . That is, openings 41 and 42 are formed at positions where the reflection sheet 40 contacts the light source 20 and the support member 30 when the inner surface of the backlight chassis 10 on which the light source 20 and the support member 30 are arranged is covered. . Thereby, the reflection sheet 40 is adhesively fixed to the inner surface of the backlight chassis 10 . Part of the light source 20 (emission part) is arranged to protrude from the opening 41 toward the display panel 100 , and part of the support member 30 is arranged to protrude from the opening 42 toward the display panel 100 .

As shown in FIG. 1, in the manufacturing process of the backlight 200, first, the light source 20 (substrate 21) and the support member 30 are arranged at predetermined positions on the inner surface of the backlight chassis 10, and then the reflective sheet is placed. 40 is placed on the inner surface of the backlight chassis 10 by passing the light source 20 and the support member 30 through the openings 41 and 42, and then the diffusion plate 50 and the optical sheets 61 and 62 are placed in this order. . Further, the display device 1 is manufactured by disposing the display panel 100 on the backlight 200 and disposing the bezel 300 so as to cover the display panel 100 in the manufacturing process.

3 is a plan view of the light source 20 and the support member 30 arranged in the backlight chassis 10. FIG. FIG. 3 shows a partial area of the backlight chassis 10 .

The light sources 20 are arranged in a matrix at regular intervals on the inner surface of the backlight chassis 10 . Specifically, as shown in FIG. 3, the light sources 20 are arranged on the inner surface of the backlight chassis 10 at intervals L1 in the row direction and the column direction. The number and spacing of the light sources 20 are not particularly limited, and are determined based on the size and display performance of the display panel 100, the performance (brightness) of the light sources 20, and the like.

Further, as shown in FIG. 2, the light source 20 is arranged such that the light emitting surface thereof is substantially parallel to the display surface of the display panel 100, and the optical axis (center) of the light emitted from the light source 20 axis) is substantially perpendicular to the display surface. That is, the backlight 200 has the structure of a direct type backlight.

The support members 30 are arranged in a zigzag manner at predetermined intervals on the inner surface of the backlight chassis 10 . For example, as shown in FIG. 3, the support member 30 is arranged at the center (interval L2) of the light sources 20 adjacent to each other in the row direction. The number of support members 30 is not limited, and is determined according to the size, thickness, weight, and deflection amount of the diffusion plate 50 due to the influence of heat and the like. A detailed configuration of the support member 30 will be described later.

The diffusion plate 50 diffuses the light emitted from the light source 20 toward the optical sheet 61 . The diffuser plate 50 is arranged with a predetermined distance from the optical sheet 61 , and the rear surface of the diffuser plate 50 is supported by the support member 30 . The optical sheets 61 and 62 collect the light diffused by the diffuser plate 50 and emit it toward the display panel 100 .

[Support member 30]
FIG. 4 is a perspective view showing the structure of the support member 30. As shown in FIG. The support member 30 includes a base material 31, support pins 32 formed on the base material 31, a first adhesive layer 33 provided on the back surface of the base material 31, and a back surface of the first adhesive layer 33. It has a reflective layer 34 and a second adhesive layer 35 provided on the back surface of the reflective layer 34 . The support pin 32 is an example of the translucent portion of the present invention. Reflective layer 34 is an example of the reflective layer of the present invention. The second adhesive layer 35 is an example of the mounting surface of the present invention.

The base material 31 and the support pins 32 are made of a translucent material that transmits light (light emitted from the light source 20). For example, the base material 31 and the support pins 32 are made of translucent resin (transparent resin). The base material 31 and the support pins 32 may be integrally formed, or may be formed separately and adhered to each other.

The reflective layer 34 is arranged above the second adhesive layer 35 and below the first adhesive layer 33 , and is adhesively fixed to the substrate 31 by the first adhesive layer 33 . The support member 30 is adhesively fixed to the backlight chassis 10 by the second adhesive layer 35 . For example, in the manufacturing process of the backlight 200 , an operator adheres the second adhesive layer 35 of the support member 30 to a predetermined position on the inner surface of the backlight chassis 10 to fix the support member 30 .

The support pins 32 are formed in a tapered shape as a whole from the substrate 31 side toward the tip side (the diffusion plate 50 side). The support pin 32 has a first vertical surface 32A extending in a direction perpendicular to the display surface of the display panel 100, a second vertical surface 32B facing the first vertical surface 32A, and the backlight chassis 10 from the diffusion plate 50 side. It includes a first slanted surface 32C and a second slanted surface 32D extending so as to widen toward the sides.

The first vertical surface 32</b>A and the second vertical surface 32</b>B are each formed in a triangular shape and constitute one side surface of the support pin 32 . The first vertical plane 32A and the second vertical plane 32B are arranged parallel to each other and perpendicular to the display surface. The first inclined surface 32</b>C and the second inclined surface 32</b>D are each formed in a rectangular shape and constitute one side surface of the support pin 32 . Also, the first inclined surface 32C and the second inclined surface 32D are arranged apart from each other on the base material 31 and connected to each other at their tips. The shape of the support pin 32 is not limited to this. For example, the support pin 32 may have a conical, pyramidal, or elliptical shape with a tapered distal end, or may have a columnar, prismatic, or spherical shape.

Here, as shown in FIG. 3, the support member 30 is arranged on a straight line that connects two adjacent light sources 20 at the shortest distance L1 in the backlight chassis 10 when the display device 1 is viewed from above. . In other words, the support member 30 is not arranged on the diagonal line connecting the two light sources 20 that are adjacent in the oblique direction. In addition, the support member 30 is arranged at a position where the first vertical surface 32A and the second vertical surface 32B are perpendicular to the straight line connecting the two adjacent light sources 20 when the display device 1 is viewed two-dimensionally. Specifically, the support members 30 are arranged such that the center of the support members 30 in the column direction is positioned on a straight line connecting two adjacent light sources 20 with the shortest distance L1. The support members 30 are arranged between the light sources 20 in a zigzag pattern. As a result, when the diffuser plate 50 comes into contact with the support members 30, the weight of the diffuser plate 50 borne by each support member 30 can be dispersed, so that uneven brightness on the display screen can be suppressed.

FIG. 5 shows a side view of part of FIG. 3 (dotted line frame P) viewed from the arrow direction P1. As shown in FIG. 5, the support member 30 is arranged between (center) two adjacent light sources 20, the first vertical surface 32A is arranged to face one (left) light source 20, The second vertical surface 32B is arranged to face the other (right) light source 20 . As a result, for example, part of high-intensity light emitted from the light sources 20 arranged on both sides of the support member 30 is incident on the inside of the support pin 32 , and the critical angle of the light incident on the inside of the support pin 32 is is transmitted through the support pin 32 and light exceeding the critical angle is reflected inside the support pin 32 . In addition, part of the low-intensity light emitted from the light source 20 arranged in an oblique direction with respect to the support member 30 is incident on the support pin 32 , and the light incident on the support pin 32 is critical. Light that does not exceed the angle is transmitted through the support pin 32 and light that exceeds the critical angle is reflected inside the support pin 32 . For example, when the light diffusely reflected inside the backlight 200 enters the support pin 32 (acrylic refractive index 1.49) with a large refractive index from the air layer (refractive index 1) with a small refractive index, it becomes critical at the boundary with the air layer. Light beyond the corners is reflected and guided inside the support pin 32 . In this way, the light reflected inside the support pin 32 is propagated toward the tip of the support pin 32 while being repeatedly reflected.

Further, the support pin 32 has a rough surface portion 321 near the diffusion plate 50 on the tip side (see FIG. 2). For example, in the example shown in FIG. 4, the support pin 32 has a first rough surface portion 321C and a second rough surface portion 321D on the tip side. The first rough surface portion 321C is arranged on the tip side of the first inclined surface 32C, and the second rough surface portion 321D is arranged on the tip side of the second inclined surface 32D. The rough surface portion 321 may be formed by roughening a portion (front end side) of the support pin 32, or may be formed by attaching a sheet on which a dot pattern is printed to a portion (front end side) of the support pin 32. It may be formed by attaching In the example shown in FIG. 4, the first rough surface portion 321C is formed by roughening a portion (front end side) of the first inclined surface 32C of the support pin 32, and the second rough surface portion 321D is formed by 32 is formed by roughening a part (front end side) of the second inclined surface 32D. Each of the rough surface portion 321, the first rough surface portion 321C, and the second rough surface portion 321D is an example of the diffusion portion of the present invention.

The rough surface portion 321 has a diffusing function of diffusing the light that has entered the inside of the support pin 32 and propagated (guided) to the tip side to be emitted outside. For example, as shown in FIG. 6, part of light R1 (LED light) emitted from the light source 20 enters the support pin 32 of the support member 30 and part of the light R1 is reflected by the support pin 32 . The light incident inside the support pin 32 is propagated (light-guided) to the tip side of the support pin 32 while being repeatedly reflected inside the support pin 32 . The light propagated to the tip side of the support pin 32 is emitted outside from the first rough surface portion 321C and the second rough surface portion 321D. The light R2 emitted from the first rough surface portion 321C and the second rough surface portion 321D is diffused and emitted by the diffusion function of the first rough surface portion 321C and the second rough surface portion 321D, as shown in FIG. Light R<b>2 (diffused light) emitted from the support member 30 is incident on the diffusion plate 50 .

According to the above configuration, the light incident on the support member 30 can be extracted from the support member 30 with high efficiency, and the light (diffused light) extracted from the support member 30 can be incident on the diffusion plate 50. can. Then, the light R2 can be efficiently made incident on the position of the diffusion plate 50 where the support member 30 is arranged. Therefore, it is possible to suppress luminance unevenness of the display screen at the portion where the support member 30 contacts the diffuser plate 50 . In addition, it is possible to make the brightness of the entire display area uniform. In the future, even if the number of light sources is reduced or the thickness of the display device 1 is reduced as the performance of LEDs is improved, the rough surface portion 321 provided on the support member 30 can diffuse the light according to the above configuration. The function makes it possible to suppress the luminance unevenness and achieve uniform luminance.

Here, the first vertical surface 32A, the second vertical surface 32B, the first inclined surface 32C, and the second inclined surface 32D, which constitute the support pin 32 of the support member 30, extend from the rear surface of the reflection sheet 40 to the opening 42 (Fig. 1) to protrude toward the display panel 100 side. Therefore, the reflection sheet 40 is positioned closer to the backlight chassis 10 than the support pins 32 (the first vertical surface 32A, the second vertical surface 32B, the first inclined surface 32C, and the second inclined surface 32D). It is arranged closer to the display panel 100 than the first adhesive layer 33 , the reflective layer 34 and the second adhesive layer 35 . That is, the base material 31 , the first adhesive layer 33 , the reflective layer 34 , and the second adhesive layer 35 are arranged closer to the backlight chassis 10 than the reflective sheet 40 .

As shown in FIG. 7 , the reflective layer 34 of the support member 30 is arranged closer to the backlight chassis 10 than the reflective sheet 40 and is arranged to be exposed from the opening 42 of the reflective sheet 40 . In other words, the opening 42 is covered with the reflective layer 34 from the back side of the reflective sheet 40 when viewed two-dimensionally. As a result, as shown in FIG. 7, when part of the light R1 emitted from the light source 20 is incident on the opening 42, it is reflected by the reflective layer 34, and the reflected light R3 is emitted directly or by the support member. 30 and enters the diffusion plate 50 . As a result, the loss of the light R1 due to the opening 42 can be suppressed, so that the utilization efficiency of the light emitted from the light source 20 can be improved. As shown in FIG. 7, the end of the opening 42 of the reflection sheet 40 is placed and fixed on the base material 31 of the support member 30 . As a result, the reflective layer 34 can reliably cover the gap between the openings 42 in a plan view.

The invention is not limited to the embodiments described above. For example, the surfaces of the first vertical surface 32A and the second vertical surface 32B of the support member 30 may be mirror-finished. Accordingly, the light R1 emitted from the light source 20 is reflected by the first vertical surface 32A and the second vertical surface 32B and enters the diffusion plate 50. As shown in FIG.

Examples of diffusion sections of the present invention are provided below. In each of the following figures, a portion of the support pin 32 including the rough surface portion 321 is shown, and the illustration of the other portions is omitted.

8A and 8B are diagrams showing the configuration of the rough surface portion 321 according to Example 1. FIG. 8A is a side view of the support pin 32 according to Example 1, and FIG. 8B is a front view of the support pin 32 of FIG. 8A viewed from the arrow direction P2. The rough surface portion 321 has a configuration in which a plurality of curved (hemispherical) convex portions (protrusions) are formed. The shape of the convex portion is not limited to a curved shape, and may be a rectangular shape. Also, the plurality of protrusions may be arranged at regular intervals, or may be arranged at random. The rough surface portion 321 can be formed by, for example, a molding die.

9A and 9B are diagrams showing the configuration of the rough surface portion 321 according to the second embodiment. 9A is a side view of the support pin 32 according to Example 2, and FIG. 9B is a front view of the support pin 32 of FIG. 9A as seen from the arrow direction P2. The rough surface portion 321 has a configuration in which a plurality of curved (hemispherical) concave portions are formed. The shape of the recess is not limited to a curved shape, and may be rectangular. Also, the plurality of recesses may be arranged at equal intervals, or may be arranged at random. The rough surface portion 321 can be formed by, for example, a molding die or laser processing.

10A and 10B are diagrams showing the configuration of the rough surface portion 321 according to Example 3. FIG. 10A is a side view of the support pin 32 according to Example 3, and FIG. 10B is a front view of the support pin 32 of FIG. 10A viewed from the arrow direction P2. The rough surface portion 321 has a configuration in which a plurality of mountain-shaped convex portions (protrusions) are formed. The shape of the convex portion is not limited to a triangular shape, and may be a rectangular shape. Moreover, the plurality of laterally extending protrusions may not be parallel to each other. Also, the plurality of protrusions may be formed to extend in the vertical direction or in the oblique direction. The rough surface portion 321 can be formed by, for example, a molding die.

11A and 11B are diagrams showing the configuration of the rough surface portion 321 according to Example 4. FIG. FIG. 11A is a side view of the support pin 32 according to Example 4, and FIG. 11B is a front view of the support pin 32 of FIG. 11A viewed from the arrow direction P2. The rough surface portion 321 has a configuration in which a plurality of valley-shaped concave portions are formed. The shape of the recess is not limited to a triangular shape, and may be a rectangular shape. Also, the laterally extending recesses may not be parallel to each other. Also, the plurality of recesses may be formed extending in the vertical direction or in the oblique direction. The rough surface portion 321 can be formed by, for example, a molding die or laser processing.

The diffusion portion of the present invention is not limited to the rough surface portion formed by surface roughening, and may be formed by printing such as silk printing used for the pattern of the light guide plate.

It should be noted that the display device 1 according to the present invention can be obtained by freely combining each embodiment shown above within the scope of the invention described in each claim, or by appropriately modifying each embodiment or omitting a part of each embodiment. It is also possible to configure by

1: display device 10: backlight chassis 20: light source 21: substrate 30: support member 31: base material 32: support pin 32A: first vertical surface 32B: second vertical surface 32C: first inclined surface 32D: second inclined surface Surface 33 : First adhesive layer 34 : Reflective layer 35 : Second adhesive layer 40 : Reflective sheet 41 : Opening 42 : Opening 50 : Diffusion plate 61 : Optical sheet 62 : Optical sheet 100 : Display panel 200 : Backlight 300 : Bezel 321 : Rough surface portion 321C : First rough surface portion 321D : Second rough surface portion

Claims (11)

a light source arranged on the back side of the display panel;
a diffusion plate arranged to face the light source;
a support member that supports the diffusion plate from the rear side of the diffusion plate;
a backlight chassis that houses the light source, the diffusion plate, and the support member;
with
The support member includes a substrate made of a translucent material, support pins formed on the substrate, and a reflective layer provided on the lower surface of the substrate,
The support pin includes a light-transmitting portion that transmits light emitted from the light source, and a diffusion portion that is disposed near the diffusion plate and diffuses and emits the light emitted from the light source to the outside. ,
part of the light emitted from the light source is reflected by the reflective layer, propagates through the base material and the translucent portion, is guided to the diffusion portion, and is emitted to the outside from the diffusion portion; display device. When the display device is viewed two-dimensionally, the area of the base material is larger than the area of the support pins,
The display device according to claim 1. further comprising a reflective sheet arranged on the back side of the display panel,
The reflective sheet has an opening,
The base material and the reflective layer are arranged on the back side of the reflective sheet and are arranged so as to be exposed from the opening of the reflective sheet.
The display device according to claim 1 or 2. The translucent part has a first vertical plane and a second vertical plane extending in a direction perpendicular to the display surface of the display panel, and a first vertical plane extending from the diffusion plate side toward the backlight chassis side. including an inclined surface and a second inclined surface;
The support member is arranged at a position where the first vertical surface and the second vertical surface are orthogonal to a straight line connecting two adjacent light sources when the display device is viewed in plan.
The display device according to any one of claims 1 to 3 . The diffusion section is arranged near the diffusion plate on each of the first inclined surface and the second inclined surface,
The display device according to claim 4 . The light-transmitting portion is formed in a tapered shape toward the diffusion plate side,
The display device according to claim 4 or 5 . A reflective sheet is disposed at a position closer to the backlight chassis than the first vertical surface, the second vertical surface, the first inclined surface, and the second inclined surface.
The display device according to any one of claims 4 to 6 . the support member further comprises a mounting surface mounted on the backlight chassis;
The reflective layer is disposed on top of the mounting surface .
The display device according to claim 7 . An opening is formed in the reflection sheet,
the first vertical surface, the second vertical surface, the first inclined surface, and the second inclined surface are arranged to protrude from the opening toward the diffusion plate;
The mounting surface is arranged closer to the backlight chassis than the reflective sheet.
The display device according to claim 8 . The support member is arranged on a straight line connecting the two adjacent light sources at the shortest distance,
The display device according to any one of claims 1 to 9 . The diffusing portion is formed by roughening a part of the translucent portion,
The display device according to any one of claims 1 to 10 .

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