Display device

Abstract

To provide a display device in which light leakage into an adjacent segment area is small.SOLUTION: A display device comprises: a luminaire that comprises a plurality of light-emitting elements and a first driving unit which drives the plurality of light-emitting elements; and a display panel that comprises a plurality of pixels and a second driving unit which drives the plurality of pixels. The plurality of light-emitting elements are segmented into a plurality of first segment areas. The plurality of pixels are segmented into a plurality of second segment areas. The plurality of light-emitting elements are independently driven in a unit of the first segment area. The first driving unit outputs a driving signal that controls light-on and light-off of the light-emitting element to the first segment area corresponding to the second segment area. A shape of the first segment area is different from a shape of the second segment area.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present embodiment relates to a display device. [Background technology]

[0002] Liquid crystal display devices using liquid crystal panels are known. In order to improve the display quality of such liquid crystal display devices, there is an increasing demand for lighting devices used in liquid crystal display devices with higher brightness, and direct lighting devices in which a light source is disposed directly under a liquid crystal panel are being considered. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-031004 A [Patent Document 2] JP 2010-085947 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present embodiment provides a display device with low light leakage into adjacent segment regions. [Means for solving the problem]

[0005] A display device according to an embodiment includes: A lighting device including a plurality of light-emitting elements and a first drive unit that drives the plurality of light-emitting elements; A display panel including a plurality of pixels and a second drive unit that drives the plurality of pixels; Equipped with The light emitting elements are divided into a plurality of first segment regions, The plurality of pixels are divided into a plurality of second segment regions, The plurality of light emitting elements are independently driven in units of the first segment regions, The first driving unit outputs a driving signal for controlling turning on and off the light-emitting element to the first segment area corresponding to the second segment area, The first segment region and the second segment region have different shapes. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is an exploded perspective view showing a display device according to the present embodiment. [Figure 2A] FIG. 2A is a plan view illustrating a segment region of the present embodiment. [Figure 2B] FIG. 2B is a plan view illustrating the segment region of this embodiment. [Diagram 3] FIG. 3 is a diagram illustrating overlapping segment regions in this embodiment. [Figure 4A] FIG. 4A is a diagram illustrating a segment region of a comparative example. [Figure 4B] FIG. 4B is a diagram illustrating a segment region of a comparative example. [Diagram 5] FIG. 5 is a diagram illustrating overlapping segment areas SA and PA in a comparative example. [Figure 6] FIG. 6 is a diagram showing the segment regions and luminance profiles of the light-emitting elements of the comparative example and this embodiment. [Figure 7] FIG. 7 is a diagram illustrating overlapping segment regions in this embodiment. [Figure 8A] FIG. 8A is a plan view showing another configuration example of the display device in the embodiment. [Figure 8B] FIG. 8B is a plan view showing another configuration example of the display device in the embodiment. [Figure 9] FIG. 9 is a diagram for explaining overlapping segment regions in this configuration example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. Note that the disclosure is merely an example, and those who are skilled in the art can easily come up with appropriate modifications while maintaining the gist of the invention, which are naturally included in the scope of the present invention. In addition, in order to make the explanation clearer, the drawings may show the width, thickness, shape, etc. of each part in a schematic manner compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate. Hereinafter, a display device according to an embodiment will be described in detail with reference to the drawings.

[0008] In this embodiment, the first direction X, the second direction Y, and the third direction Z are perpendicular to each other, but may intersect at an angle other than 90 degrees. The direction toward the tip of the arrow of the third direction Z is defined as up or upward, and the direction opposite to the direction toward the tip of the arrow of the third direction Z is defined as down or downward. The first direction X, the second direction Y, and the third direction Z are sometimes called the X direction, the Y direction, and the Z direction, respectively.

[0009] Furthermore, in the case of "a second member above the first member" and "a second member below the first member," the second member may be in contact with the first member or may be located away from the first member. In the latter case, a third member may be interposed between the first and second members. On the other hand, in the case of "a second member above the first member" and "a second member below the first member," the second member is in contact with the first member.

[0010] Also, it is assumed that an observation position for observing the display device is located at the tip side of the arrow in the third direction Z, and a planar view refers to a view from this observation position toward the XY plane defined by the first direction X and the second direction Y. A cross-sectional view refers to a view of a cross section of the display device in the XZ plane defined by the first direction X and the third direction Z, or in the YZ plane defined by the second direction Y and the third direction Z.

[0011] FIG. 1 is an exploded perspective view showing a display device according to the present embodiment. The display device DSP includes a display panel PNL and an illumination device ILD. In this embodiment, the display panel PNL is a commonly known transmissive or semi-transmissive liquid crystal display panel. The display panel PNL has a plurality of pixels PX in a display area DA. However, the display panel PNL is not limited to a liquid crystal display panel, and may be any display panel that requires a separate light source, such as a MEMS (Micro Electro-Mechanical System) display panel.

[0012] The illumination device ILD is disposed below and facing the display panel PNL. The illumination device ILD emits light toward the display panel PNL. In this embodiment, the illumination device ILD functions as a backlight unit. The display panel PNL displays an image by selectively transmitting the light from the illumination device ILD.

[0013] 1, the illumination device ILD includes a wiring board CBS, a plurality of light-emitting elements LEM, a driving unit DVM, a protective layer OC, a diffusion sheet DFS, and a prism sheet PSM. The wiring board CBS, the plurality of light-emitting elements LEM, the protective layer OC, and the prism sheet PSM are laminated in this order in the third direction Z.

[0014] In this embodiment, the wiring board CBS is configured by a printed circuit board (PCB: Printed Circuit Board). However, the wiring board CBS is not limited to a printed circuit board, and may be configured by a flexible printed circuit board (FPC: Flexible Printed Circuit). The wiring board CBS has a main surface MSF. A light emitting area LA is provided on the main surface MSF. The light emitting area LA faces at least the display area DA of the display panel PNL.

[0015] A plurality of light-emitting elements LEM are provided in the light emission area LA. The plurality of light-emitting elements LEM are arranged in a matrix along the first direction X and the second direction Y. In this embodiment, the light-emitting elements LEM are mini-LEDs (mini-light-emitting diodes). A driving unit DVM for driving the plurality of light-emitting elements LEM is mounted on the main surface MSF outside the light emission area LA. The light-emitting elements LEM output light of a specific wavelength.

[0016] In plan view, the light emitting element LEM has a square shape. However, the shape of the light emitting element LEM may be a shape other than a square, such as a rectangle. In plan view, the length of one side of the light emitting element LEM, which is a mini LED, is, for example, more than 100 μm and less than 300 μm. The length of one side of the light emitting element LEM, which is a mini LED, may be more than 100 μm and less than 200 μm.

[0017] The light-emitting element LEM may be a micro LED having a longest side length of 100 μm or less, which is an LED smaller than a mini LED. Alternatively, the light-emitting element LEM may be an LED having a longest side length of 1 mm or less. Alternatively, the light-emitting element LEM may be a general LED having a longest side length of 1000 μm or more, which is a larger LED than a mini LED. The length of one side of the light-emitting element LEM, which is a general LED, is, for example, 300 μm or more and 350 μm or less.

[0018] The protective layer OC is configured as a light-transmitting layer that transmits the wavelength of light emitted by the light-emitting element LEM. The protective layer OC is made of, for example, a silicone resin. It is sufficient that the protective layer OC is provided so as to cover the light-emitting element LEM.

[0019] The diffusion sheet DFS has two diffusion sheets DFS1 and DFS2. However, the number of diffusion sheets is not limited to this. A single diffusion sheet having a predetermined thickness may be provided, or multiple diffusion sheets may be laminated.

[0020] The prism sheet PSM is composed of two refractive prism sheets PSM1 and PSM2 arranged at right angles to each other. However, the prism sheet PSM may be composed of a total reflection prism sheet instead of the refractive prism sheet PSM1. The total reflection prism sheet has a simple structure and is excellent in light utilization efficiency and vertical light collection.

[0021] The display panel PNL includes a substrate SUB1, a substrate SUB2, a liquid crystal layer LCY, a flexible wiring substrate FC, and a driving unit IPC. The liquid crystal layer LCY is provided between the substrates SUB1 and SUB2. A sealant (not shown) is provided between the substrates SUB1 and SUB2, surrounding the ends of the substrates. The liquid crystal layer LCY is provided inside the area surrounded by the sealant.

[0022] The substrate SUB1 has an end portion Ex that does not overlap with the substrate SUB2. A flexible wiring board FC is provided at the end portion Ex. A driving unit IPC is connected to the flexible wiring board FC. The driving unit IPC is connected to pixels PX in the display area DA via the flexible wiring board FC and drives the pixels PX. An image is displayed in the display area DA by driving the pixels PX.

[0023] 2A and 2B are plan views illustrating the segment regions of this embodiment. As shown in Fig. 2A, the light emission region LA is divided into a plurality of segment regions SA. In this embodiment, the multiple segment regions SA are arranged in a matrix in a direction that forms an angle of 45° with the first direction X and a direction that forms an angle of 45° with the second direction Y. However, the multiple segment regions SA do not have to be arranged in a matrix, and may be positioned adjacent to each other.

[0024] In the example shown in FIG. 2A, each of the multiple segment areas SA has one light-emitting element LEM. In other words, the multiple light-emitting elements LEM are each divided to form multiple segment areas SA. However, the number of light-emitting elements LEM provided in the segment area SA does not have to be one, and multiple light-emitting elements LEM may be provided. In this embodiment, the light-emitting element LEM is provided in the center of the segment area SA. The pitch between adjacent light-emitting elements LEM corresponds to the pitch between adjacent segment areas SA.

[0025] The light-emitting elements LEM provided in different segment areas SA are simultaneously or separately driven on and off by the driving unit DVM. For example, the driving unit DVM can be driven by a method called local dimming. In local dimming driving, the multiple light-emitting elements LEM are driven and controlled independently for each divided area. Only the areas of the image that need to be illuminated are illuminated by the light-emitting element LEM, and the illumination light from the light-emitting element LEM is not emitted to the areas of the image that do not need to be illuminated. In other words, only the areas of the image that need to be illuminated are turned on by the multiple light-emitting elements LEM, and the light-emitting elements LEM are turned off in the areas that do not need to be illuminated. This makes it possible to further increase the contrast ratio of the image displayed on the display panel PNL.

[0026] As shown in Fig. 2B, the pixels PX provided in the display area DA are divided into a plurality of segment areas PA. A plurality of pixels PX are provided in one segment area PA. For example, 10x10, i.e., 100 pixels PX may be provided in one segment area PA. However, the number of pixels PX provided in one segment area PA is not limited to this.

[0027] The segment area SA is the minimum unit in local dimming driving. A group of light-emitting elements LEM arranged in one segment area SA are driven to be simultaneously turned on (on state) or off (off state). One segment area SA corresponds to one segment area PA. A group of pixels PX arranged in the segment area PA are illuminated by the group of light-emitting elements LEM.

[0028] In response to an image displayed in the display area DA, the driving unit IPC outputs driving signals to the pixels PX in the segment area PA. The driving unit DVM outputs driving signals to the segment areas SA corresponding to each segment area PA, which control turning on and off the light-emitting elements LEM. For example, when a change occurs in the image, the driving unit IPC outputs a driving signal corresponding to the change. The driving unit DVM outputs a driving signal for controlling the turning on and off of the light emitting element LEM to the corresponding segment area SA in response to the change in the image. Although not shown, a driving element may be provided that is connected to the driving units IPC and DVM and outputs a control signal to each of them. The driving signals of the driving units IPC and DVM are output based on the control signal from the driving element.

[0029] 3 is a diagram for explaining overlapping segment areas in this embodiment. The shape of the segment area SA in this embodiment is different from the shape of the segment area PA. Details of FIG. 3 will be described later.

[0030] Figures 4A and 4B are diagrams for explaining segment areas in a comparative example, and Figure 5 is a diagram for explaining overlapping segment areas SA and PA in the comparative example. 4A, 4B, and 5, the segment area SA of the light-emitting element LEM and the segment area PA of the pixel PX have the same shape. If the segment areas SA and PA have the same shape, there is a risk that the light of the light-emitting element LEM of one segment area SA will leak not only into the corresponding segment area PA but also into the segment area PA adjacent to the segment area PA. This will prevent the adjacent segment area PA from displaying the desired image.

[0031] In this embodiment, since the segment areas SA and PA have different shapes, there is little light leakage to the adjacent segment area PA, making it possible to obtain a display device with improved display quality.

[0032] 2A, 2B, and 3, the present embodiment will be described. The segment area SA has a square shape. Two pairs of opposing sides of the segment area SA are inclined at 45° with respect to the first direction X and the second direction Y, respectively. The segment area PA has a rectangular shape with its long sides extending along the first direction X and its short sides extending along the second direction Y. That is, the shape of the segment area PA is a rectangle that is long in the left-right direction on the page. The long sides of the segment area PA have the same length as the diagonal of the segment area SA. 3, the segment area PA covers the segment area SA along the first direction X. On the other hand, along the second direction Y, a part of the segment area PA does not overlap with the segment area SA.

[0033] 3 and 5, the pitches of the segment areas SA in the first direction X and the second direction Y are respectively denoted by PSx and PSy. The pitches of the segment areas PA in the first direction X and the second direction Y are respectively denoted by PPx and PPy. The pitch PPx in this embodiment is PPx=√(PSx) 2 +(PSy) 2 In this embodiment, the pitch PPy is expressed as PPy=(√((PSx) 2 +(PSy) 2 )) / 2. The area of ​​the segment area PA is expressed as ((PSx) 2 +(PSy) 2 ) / 2. On the other hand, the area of ​​the segment area PA in the comparative example is PPx×PPy.

[0034] In this embodiment and the comparative example, the area of ​​the segment area SA is PPx×PPy. In this embodiment, PPx and PPy may be determined so that the area of ​​the segment region PA is the same as the area of ​​the segment region SA. That is, the pitches PPx and PPy are determined as follows: ((PSx) 2 +(PSy) 2 ) / 2=PPx×PPy.

[0035] Fig. 6 is a diagram showing the segment areas of the comparative example and the present embodiment, and the luminance profile of the light-emitting element. For ease of understanding, in Fig. 6, the symbols of the segment areas of the comparative example and the present embodiment are different from those described above. Segment areas SAb and PAb are segment areas SA and PA of the comparative example, and are similar to Fig. 5. Segment areas SAa and PAa are segment areas SA and PA of the present embodiment, and are similar to Fig. 3. Profile PF is the luminance profile of light emitted from the light-emitting element LEM.

[0036] In the profile PF, a region of high brightness including a maximum value is designated as p1, a region adjacent to region p1 is designated as p2, and a region outside region p2 is designated as p3. In the comparative example, the segment area PAb is illuminated using only the light from the area p1, and the light from the areas p2 and p3 is emitted to the segment area PAb adjacent to the segment area PAb.

[0037] On the other hand, the segment area PAa of this embodiment is illuminated not only by the light of the area p1 but also by the light of the area p2. The light of the area p3 is emitted to the adjacent segment area PAa, but the luminance is low, so it does not affect the display quality. In this way, in this embodiment, a display device with little light leakage to the adjacent segment area PAa can be obtained.

[0038] Fig. 7 is a diagram for explaining overlapping segment areas in this embodiment. The configuration example shown in Fig. 7 is different from the configuration example shown in Fig. 3 in that the segment area PA is a rectangle that is long in the vertical direction of the paper surface. 7, the long sides of the segment area PA extend along the second direction Y, and the short sides extend along the first direction X. As in FIG. 3, the long sides of the segment area PA have the same length as the diagonal of the segment area SA. It is possible to obtain a display device with little light leakage also in the configuration example shown in Fig. 7. As a result, it is possible to obtain a display device with improved display quality.

[0039] <Configuration example 1> 8A and 8B are plan views showing another example of the configuration of the display device according to the embodiment. The example shown in Fig. 8A and 8B is different from the example shown in Fig. 3 in that the segment areas SA and PA are both parallelograms in plan view.

[0040] As shown in Fig. 8A, the segment area SA of this configuration example has a parallelogram shape. The direction inclined at an angle θ1 clockwise from the first direction X is designated as D1, and the direction inclined at an angle θ2 clockwise from the second direction Y is designated as D2. Two pairs of opposing sides of the segment area SA extend along the directions D1 and D2, respectively. All the sides of the segment area SA may have the same length. In other words, the segment area SA may have a rhombus shape. The light emitting elements LEM are arranged in a matrix along the directions D1 and D2.

[0041] 8B, the segment area PA has a parallelogram shape. The direction inclined clockwise from the first direction X by an angle θ3 is designated as D3, and the direction inclined clockwise from the second direction Y by an angle θ4 is designated as D4. The long side of the segment area PA extends along the direction D3, and the short side extends along the direction D4.

[0042] 9 is a diagram illustrating overlapping segment areas SA and PA in this configuration example. The long side of the segment area PA has the same length as at least one of the diagonal lines of the segment area SA. This configuration example also provides the same effects as the embodiment.

[0043] In the present disclosure, the segment areas SA and PA are also referred to as a first segment area and a second segment area, respectively. The driving units DVM and IPC are also referred to as a first driving unit and a second driving unit, respectively.

[0044] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0045] DSP...display device, DVM...driver, ILD...illuminator, IPC...driver, LEM...light-emitting element, PA...segment area, PNL...display panel, PPx...pitch, PPy...pitch, PX...pixel, SA...segment area.

Claims

1. A lighting device including a plurality of light-emitting elements and a first drive unit that drives the plurality of light-emitting elements; A display panel including a plurality of pixels and a second drive unit that drives the plurality of pixels; Equipped with The light emitting elements are divided into a plurality of first segment regions, The plurality of pixels are divided into a plurality of second segment regions, The plurality of light emitting elements are independently driven in units of the first segment regions, The first driving unit outputs a driving signal for controlling turning on and off the light-emitting element to the first segment area corresponding to the second segment area, A display device, wherein the first segment area and the second segment area have different shapes.

2. The first segment region has a square shape, The display device according to claim 1 , wherein the second segment region has a rectangular shape.

3. The display device according to claim 1 , wherein the first segment area and the second segment area each have a parallelogram shape.

4. The display device according to claim 1 , wherein the first segment region has a diamond shape.

5. The display device according to claim 2 , wherein a long side of the second segment region has the same length as one of the diagonals of the first segment region.

6. The display device according to claim 1 , wherein each of the plurality of light-emitting elements is provided in each of the plurality of first segment regions.

7. The display device according to claim 1 , wherein the display panel is a liquid crystal display panel.

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