Display device

Abstract

To provide a display device 1 including a display panel 10 that allows light to enter from two side surfaces on the mutually opposite sides, in which the luminance of pixels P when a plurality of input gradation values corresponding to the pixels P are equal to each other is made homogeneous.SOLUTION: A display device 1 includes: a display panel 10; a light source device 20 that is disposed on a side of the display panel 10 and emits first light from a first side surface 10c of the display panel 10 toward a second side surface 10d on the opposite side of the first side surface 10c; a reflection member 30 that is disposed on the second side surface 10d and reflects the first light as second light from the second side surface 10d toward the first side surface 10c; and a driving circuit that calculates a light quantity totaling a first light quantity RA1 of the first light and a second light quantity RA2 of the second light in each of the pixels P and output gradation values corresponding to the pixels P on the basis of input gradation values of image signals, and applies the voltage according to the output gradation value to each of the pixels P.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 discloses a display device configured so that the background on one side of a display panel can be seen from the other side. The display device in Patent Document 1 is a so-called see-through display, and includes a display panel having a liquid crystal layer containing polymer-dispersed liquid crystal, and a light source disposed opposite to the side of the display panel.

[0003] Furthermore, Patent Document 2 discloses a reflective liquid crystal display device including a liquid crystal panel, a light source disposed on an end face side of the liquid crystal panel, and a side reflector disposed on the opposite side of the liquid crystal panel from the light source. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-160254 A [Patent Document 2] JP 2010-230835 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the display device of Patent Document 1, light (first light) from a light source (light source device) enters a first side surface of a display panel and propagates through the display panel toward a second side surface opposite to the first side surface. Elements such as switching elements and electrodes are arranged on the display panel, and a part of the first light propagating through the display panel is consumed by these elements. As a result, the amount of the first light decreases as the first light propagates through the display panel. Therefore, the amount of the first light on the second side surface of the display panel is smaller than the amount of the first light on the first side surface. In this case, when the grayscale values ​​corresponding to the multiple pixels are equal to each other, the luminance of the pixel on the second side surface is lower than the luminance of the pixel on the first side surface.

[0006] Therefore, it is conceivable to dispose the side reflector disclosed in Patent Document 2 on the second side of the display panel. In this case, the side reflector reflects the first light from the second side toward the first side. The second light reflected by the side reflector propagates through the display panel, thereby increasing the amount of light in the display panel.

[0007] However, even the second light reflected by the side reflector is partially consumed as it propagates through the display panel. Therefore, the amount of light in the display panel, which is the sum of the first light and the second light, is smaller in an intermediate portion between the portion on the first side surface side and the portion on the second side surface side than in the portion on the first side surface side and the portion on the second side surface side. In this case, when multiple gradation values ​​corresponding to multiple pixels are equal to each other, it may not be possible to obtain the desired pixel brightness in the intermediate portion.

[0008] The present disclosure aims to achieve uniform pixel brightness in a display device having a display panel to which light is incident from two opposing sides when multiple input gradation values ​​corresponding to multiple pixels are equal to each other. [Means for solving the problem]

[0009] The display device of the present disclosure includes a display panel having a display area overlapping with a plurality of pixels arranged in a matrix in a planar view, a light source device arranged on a side of the display panel and emitting a first light from a first side surface of the display panel toward a second side surface opposite the first side surface, a reflective member arranged on the second side surface and reflecting the first light from the second side surface toward the first side surface as a second light, and a drive circuit that calculates an output gradation value corresponding to the plurality of pixels based on a combined light amount of a first light amount and a second light amount of the second light in each of the plurality of pixels and an input gradation value of an image signal, and applies a voltage according to the output gradation value to each of the plurality of pixels.

[0010] Moreover, the display device of the present disclosure includes a display panel having a display area overlapping with a plurality of pixels arranged in a matrix in a planar view; a light source device arranged on a side of the display panel and emitting a first light from a first side surface of the display panel toward a second side surface opposite the first side surface; a reflective member arranged on the second side surface of the display panel and reflecting the first light toward the first side surface; and a drive circuit that calculates output gradation values ​​corresponding to the plurality of pixels based on input gradation values ​​of an image signal and applies a voltage corresponding to the output gradation value to each of the plurality of pixels, wherein when the input gradation values ​​corresponding to the plurality of pixels are equal to each other, the drive circuit increases and then decreases the output gradation values ​​corresponding to a plurality of pixels among the plurality of pixels that are arranged along a first direction from the first side surface to the second side surface along the first direction.

[0011] Moreover, the display device of the present disclosure includes a display panel having a display area overlapping with a plurality of pixels arranged in a matrix in a planar view, a light source device arranged on a side of the display panel and emitting a first light from a first side surface of the display panel toward a second side surface opposite the first side surface, a second light source device arranged on the side of the display panel and emitting a third light from the second side surface toward the first side surface, and a drive circuit that calculates output gradation values ​​corresponding to the plurality of pixels based on a combined light amount of a first light amount and a third light amount of the third light in each of the plurality of pixels and an input gradation value of an image signal, and applies a voltage according to the output gradation value to each of the plurality of pixels. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a configuration of a display device according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a plan view of the display device. [Diagram 3] FIG. 3 is a diagram showing a circuit configuration of the display panel. [Figure 4] FIG. 4 is a cross-sectional view of the display panel. [Diagram 5] FIG. 5 is a partially enlarged cross-sectional view of the display panel. [Figure 6] FIG. 6 is a diagram showing the operations of the first drive circuit and the second drive circuit when an image is displayed on the display panel. [Figure 7] FIG. 7 is a diagram showing the light amounts of a plurality of pixels arranged along a first direction from a first side surface to a second side surface. [Figure 8] FIG. 8 is a flowchart executed by the first driving circuit. [Figure 9] FIG. 9 is a diagram showing output gradation values ​​when the input gradation values ​​of a plurality of pixels are equal to one another and the total light amount corresponds to the total light amount shown in FIG. [Figure 10] FIG. 10 is a diagram showing a configuration of a display device according to a second embodiment of the present disclosure. [Figure 11]FIG. 11 is a diagram showing the light amounts of a plurality of pixels arranged along a first direction from a first side surface to a second side surface in a display device according to a second embodiment of the present disclosure. [Figure 12] FIG. 12 is a flowchart executed by the first driving circuit of the display device according to the second embodiment of the present disclosure. [Figure 13] FIG. 13 is a diagram showing output gradation values ​​when a plurality of pixels have equal input gradation values ​​and the second total amount of light is the second total amount of light shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Each embodiment of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to the contents described in the following embodiments. In addition, the components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the components described below can be appropriately combined.

[0014] The disclosure is merely an example, and those who are skilled in the art can easily come up with appropriate modifications while keeping the gist of the disclosure are naturally included in the scope of the disclosure. In addition, in order to make the explanation clearer, the width, thickness, shape, etc. of each part may be shown diagrammatically compared to the actual embodiment, but it is merely an example and does not limit the interpretation of the disclosure. In addition, in this specification and each figure, the same symbols are used for elements similar to those described above with respect to the previous figures, and detailed explanations may be omitted as appropriate.

[0015] The X direction and the Y direction shown in the drawings correspond to directions parallel to the plate surface of the substrate included in the display device 1. The +X side and the -X side of the X direction and the +Y side and the -Y side of the Y direction correspond to the sides of the display device 1. The Z direction corresponds to the thickness direction of the display device 1, the +Z side of the Z direction corresponds to the front side where an image is displayed in the display device 1, and the -Z side of the Z direction corresponds to the rear side of the display device 1. In addition, in this specification, "planar view" means viewing the display device 1 from the +Z side toward the -Z side along the Z direction. The Y direction corresponds to the first direction W1. In addition, the X, Y, and Z directions are merely examples, and the present disclosure is not limited to these directions.

[0016] First Embodiment Fig. 1 is a diagram showing a configuration of a display device 1 according to a first embodiment of the present disclosure. Fig. 2 is a plan view of the display device 1. The display device 1 displays an image based on an image signal output from an external device (not shown) electrically connected via a first flexible wiring board 2a. The display device 1 includes a display panel 10, a light source device 20, a reflective member 30, a first drive circuit 40 (corresponding to a "drive circuit"), and a second drive circuit 50.

[0017] The display panel 10 is a so-called see-through display (transparent display). In the display panel 10, the background on one plate surface (e.g., the front surface 10a) of the display panel 10 can be seen from the other plate surface (e.g., the back surface 10b) side. The display panel 10 has a display area DA on the plate surface (front surface 10a) where an image is displayed. The display panel 10 includes a first substrate 11, a second substrate 12, a liquid crystal layer 13, a first base material 14, and a second base material 15.

[0018] The first substrate 11 and the second substrate 12 are rectangular in plan view and have light-transmitting properties. The first substrate 11 and the second substrate 12 are made of, for example, a resin such as polyethylene terephthalate or glass. The first substrate 11 has an exposed portion E that is exposed from the second substrate 12 in plan view. The first substrate 11 is disposed on the rear surface 12b side of the second substrate 12. The front surface 11a of the first substrate 11 and the rear surface 12b of the second substrate 12 face each other. The liquid crystal layer 13 is disposed between the first substrate 11 and the second substrate 12.

[0019] 2, the display area DA overlaps with a plurality of pixels P arranged in a matrix along the X and Y directions in a plan view. The pixels P have a square shape in a plan view. The liquid crystal layer 13 and the pixels P will be described in detail later.

[0020] The first substrate 14 and the second substrate 15 shown in FIG. 1 and FIG. 2 protect the first substrate 11, the second substrate 12, and the liquid crystal layer 13. The first substrate 14 and the second substrate 15 are rectangular in plan view and have light-transmitting properties. The first substrate 14 and the second substrate 15 are made of, for example, glass or resin. The first substrate 14 is attached to the back surface 11b of the first substrate 11 via a first adhesive portion 16. The second substrate 15 is attached to the front surface 12a of the second substrate 12 via a second adhesive portion 17. The first adhesive portion 16 and the second adhesive portion 17 have light-transmitting properties and are formed by curing an adhesive.

[0021] The front surface 11a and the back surface 11b of the first substrate 11, the front surface 12a and the back surface 12b of the second substrate 12, the front surface 14a and the back surface 14b of the first base material 14, and the front surface 15a and the back surface 15b of the second base material 15 are all flat and parallel to each other. The front surface 15a of the second base material 15 corresponds to the front surface 10a of the display panel 10, and the back surface 14b of the first base material 14 corresponds to the back surface 10b of the display panel 10.

[0022] The first XL side surface 11c, the second XL side surface 12c, the third XL side surface 14c, and the fourth XL side surface 15c, which are the -X side surfaces of the first substrate 11, the second substrate 12, the first base material 14, and the second base material 15, are each flat and parallel to one another. The first XR side surface 11d, the second XR side surface 12d, the third XR side surface 14d, and the fourth XR side surface 15d, which are the +X side surfaces of the first substrate 11, the second substrate 12, the first base material 14, and the second base material 15, are each flat and parallel to one another.

[0023] The first YB side surface 11e, the second YB side surface 12e, the third YB side surface 14e, and the fourth YB side surface 15e, which are side surfaces on the -Y side of the first substrate 11, the second substrate 12, the first base material 14, and the second base material 15, are flat and parallel to each other. The first YB side surface 11e, the second YB side surface 12e, the third YB side surface 14e, and the fourth YB side surface 15e correspond to the first side surface 10c of the display panel 10.

[0024] Furthermore, the first YF side surface 11f, the second YF side surface 12f, the third YF side surface 14f, and the fourth YF side surface 15f, which are side surfaces on the +Y side of the first substrate 11, the second substrate 12, the first base material 14, and the second base material 15, are each flat and parallel to one another. The first YF side surface 11f, the second YF side surface 12f, the third YF side surface 14f, and the fourth YF side surface 15f correspond to the second side surface 10d of the display panel 10.

[0025] The light source device 20 is disposed on the side of the display panel 10. Specifically, the light source device 20 is on the first side surface 10c side of the display panel 10, and faces the fourth YB side surface 15e of the second base material 15. The light source device 20 emits light from the first side surface 10c side of the display panel 10 toward the second side surface 10d side opposite the first side surface 10c (details will be described later). The light source device 20 is fixed to the second base material 15 via a support 18. The light source device 20 includes a light-emitting section 21 and a light-guiding section 22.

[0026] There are a plurality of light emitting units 21, which are arranged along the X direction. The light emitting unit 21 includes a first light emitter 21a of a first color, a second light emitter 21b of a second color, and a third light emitter 21c of a third color. The first color, the second color, and the third color are different from each other, and the first color is red, the second color is green, and the third color is blue. That is, the color of the light of the first light emitter 21a is red, the color of the light of the second light emitter 21b is green, and the color of the light of the third light emitter 21c is blue. Hereinafter, when the first light emitter 21a, the second light emitter 21b, and the third light emitter 21c are described without distinction, they are simply referred to as "light emitters SL."

[0027] It goes without saying that the number of light emitters SL in the light emitting unit 21 and the color of the light are not limited to the above. For example, the number of light emitters SL may be one, and the color of the light emitters SL may be white. In this case, a grayscale or black and white image is displayed in the display area DA.

[0028] The light emitter SL emits light toward the light guide section 22. The light emitter SL is, for example, an LED (Light Emitting Diode). The light of the light emitter SL corresponds to the light of the light source device 20. Hereinafter, the light of the light source device 20 (i.e., the light of the light emitter SL) will be referred to as a first light.

[0029] The light guide 22 is rectangular and has an opposing surface 22a facing the light emitter SL, and an opposite surface 22b that is on the opposite side of the opposing surface 22a and faces the fourth YB side surface 15e of the second base material 15. The light guide 22 has a shape that is continuous from the fourth XL side surface 15c to the fourth XR side surface 15d in a plan view. The light guide 22 is translucent. The first light of the light emitter SL enters the light guide 22 from the opposing surface 22a, is diffused within the light guide 22, and is emitted from the opposite surface 22b toward the fourth YB side surface 15e of the second base material 15 with the amount of light being uniformed.

[0030] The first light of the light emitter SL incident from the 4YB side surface 15e of the second base material 15 propagates through the display panel 10 from the first side surface 10c of the display panel 10 toward the second side surface 10d opposite to the first side surface 10c. Specifically, the first light of the light emitter SL is reflected by the front surfaces 11a, 12a, 14a, 15a and rear surfaces 11b, 12b, 14b, 15b of the first substrate 11, the second substrate 12, the first base material 14, and the second base material 15, respectively, within the display panel 10, and propagates to the second side surface 10d.

[0031] The reflective member 30 is disposed on a side surface of the display panel 10 opposite to the side surface facing the light source device 20. Specifically, the reflective member 30 is disposed on the second side surface 10d. The reflective member 30 is a so-called reflective tape. The reflective member 30 includes a reflective layer 31 and an adhesive layer 32 overlapping the reflective layer 31.

[0032] The reflective layer 31 is in the form of a film. The material of the reflective layer 31 has a relatively high reflectance. The material of the reflective layer 31 is, for example, aluminum and silver. The adhesive layer 32 has light transmissivity. The material of the adhesive layer 32 is an optical elastic resin, which is hardened by ultraviolet light.

[0033] The reflecting member 30 reflects the first light from the second side surface 10d toward the first side surface 10c. That is, the first light emitted by the light source device 20 propagates through the display panel 10 from the first side surface 10c toward the second side surface 10d, reaches the reflecting member 30, and is reflected by the reflecting member 30 toward the first side surface 10c. Hereinafter, the first light reflected by the reflecting member 30 is referred to as the second light. That is, the reflecting member 30 reflects the first light from the second side surface 10d toward the first side surface 10c as the second light. In other words, the first light is reflected by the reflecting member 30, and the second light is incident from the second side surface 10d of the display panel 10.

[0034] 3 is a diagram showing a circuit configuration of the display panel 10. As shown in FIGS. 1 and 3, the first driving circuit 40 is disposed on the first substrate 11. The first driving circuit 40 calculates an output gradation value, which will be described later, based on an image signal transmitted from an external device. The first driving circuit 40 applies a voltage to a plurality of pixels P in accordance with the output gradation value (which will be described in detail later). The first driving circuit 40 includes a signal processing circuit 41, a signal output circuit 42, and a scanning circuit 43.

[0035] The signal processing circuit 41 generates a plurality of pixel drive signals based on an image signal (details will be described later), and outputs the plurality of pixel drive signals to the signal output circuit 42. In addition, the signal processing circuit 41 outputs a clock signal to the signal output circuit 42 and the scanning circuit 43, which synchronizes the operation of the signal output circuit 42 and the operation of the scanning circuit 43.

[0036] The signal output circuit 42 outputs a plurality of pixel drive signals to the corresponding pixels P. As shown in Fig. 3, the signal output circuit 42 and the plurality of pixels P are electrically connected via a plurality of signal lines Lb extending along the Y direction.

[0037] The scanning circuit 43 scans the multiple pixels P in synchronization with the output of the pixel drive signal by the signal output circuit 42. The scanning circuit 43 and the multiple pixels P are electrically connected via multiple scanning lines Lc extending along the X direction.

[0038] Each of the pixels P includes a switching element SW, a pixel electrode PE, a common electrode CE, a liquid crystal capacitance LC, and a storage capacitance KC.

[0039] The switching element SW is formed of, for example, a thin film transistor (TFT). In the switching element SW, a source electrode and a signal line Lb are electrically connected, and a gate electrode and a scanning line Lc are electrically connected.

[0040] The pixel electrode PE is connected to a drain electrode of the switching element SW. A plurality of common electrodes CE are arranged corresponding to the plurality of scanning lines Lc. The pixel electrodes PE and the common electrode CE are light-transmitting.

[0041] The liquid crystal capacitance LC is a capacitance component of the liquid crystal material of the liquid crystal layer 13, which is described later, located between the pixel electrode PE and the common electrode CE. The storage capacitance KC is disposed between an electrode having the same potential as the common electrode CE and an electrode having the same potential as the pixel electrode PE.

[0042] Fig. 4 is a cross-sectional view of the display panel 10. Note that the first substrate 14 and the second substrate 15 are omitted in Fig. 4. Signal lines Lb (not shown), pixel electrodes PE, and scanning lines Lc (not shown) are arranged on the front surface 11a of the first substrate 11 in an electrically insulated state. In the display panel 10, an area defined by two adjacent signal lines Lb and two adjacent scanning lines Lc in a plan view corresponds to a pixel P.

[0043] A first alignment film AL1 is disposed on the front surface 11a of the first substrate 11. The alignment direction of the first alignment film AL1 is along the Y direction. Signal lines Lb, pixel electrodes PE, and scanning lines Lc are disposed between the first substrate 11 and the first alignment film AL1.

[0044] A common electrode CE and a second alignment film AL2 are disposed on the rear surface 12b of the second substrate 12. The common electrode CE is disposed between the second substrate 12 and the second alignment film AL2. The alignment direction of the second alignment film AL2 is along the Y direction. That is, the alignment direction of the first alignment film AL1 and the alignment direction of the second alignment film AL2 are parallel to each other. Note that the alignment direction of the first alignment film AL1 and the alignment direction of the second alignment film AL2 may be perpendicular to each other.

[0045] 5 is a partially enlarged cross-sectional view of the display panel 10. The liquid crystal layer 13 includes a polymer dispersed liquid crystal. Specifically, the liquid crystal layer 13 has a three-dimensional mesh-like polymer network 13a and liquid crystal molecules 13b.

[0046] The polymer network 13a is formed by polymerizing monomers aligned by the first alignment film AL1 and the second alignment film AL2 with ultraviolet light, heat, etc. The liquid crystal molecules 13b are present in the gaps in the polymer network 13a.

[0047] 1, the second drive circuit 50 is disposed on the support 18. The second drive circuit 50 drives the light source device 20 based on an optical control signal output from an external device (not shown) electrically connected via the second flexible wiring board 2b.

[0048] Next, a description will be given of the basic operation of the display device 1 when the display panel 10 displays an image. The first drive circuit 40 and the second drive circuit 50 drive the display panel 10 and the light source device 20 by a field sequential method.

[0049] First, a case will be described in which no image signal and no light control signal are transmitted to the display device 1, and the display panel 10 does not display an image. In this case, the first drive circuit 40 does not output a pixel drive signal, and no voltage is applied to the pixel electrode PE. In addition, the second drive circuit 50 does not drive the light source device 20, and no light is emitted from the light emitter SL.

[0050] When no voltage is applied to the pixel electrode PE, the optical axis AX1 of the polymer network 13a and the optical axis AX2 of the liquid crystal molecules 13b are regulated by the alignment directions of the first alignment film AL1 and the second alignment film AL2, as shown in Fig. 5. In the first embodiment, when no voltage is applied to the pixel electrode PE, the optical axis of the polymer network 13a and the optical axis of the liquid crystal molecules 13b are parallel to each other and aligned along the Y direction.

[0051] The ordinary refractive index of the polymer network 13a and the ordinary refractive index of the liquid crystal molecules 13b are equal to each other. Therefore, when no voltage is applied to the pixel electrode PE, the difference between the refractive index of the polymer network 13a and the refractive index of the liquid crystal molecules 13b is zero in all directions. Therefore, the light propagating through the display panel 10 is not scattered. That is, in this case, the liquid crystal layer 13 is in a transmissive state in which it does not scatter the light propagating through the display panel 10.

[0052] When the liquid crystal layer 13 is in a transmissive state, the background on the other plate surface side (e.g., rear surface side 10b) of the display panel 10 can be seen from one plate surface side (e.g., front surface side 10a) of the display panel 10. When the liquid crystal layer 13 is in a transmissive state, the light of the light emitter SL propagating within the display panel 10 is hardly scattered. Therefore, when the liquid crystal layer 13 is in a transmissive state, the background on the other plate surface side of the display panel 10 can be seen from one plate surface side of the display panel 10 even when the light of the light emitter SL is emitted based on a light control signal.

[0053] Next, a case will be described in which an image signal and a light control signal are transmitted to the display device 1 and the display panel 10 displays an image. First, a state in which the first drive circuit 40 outputs a pixel drive signal and a voltage is applied to the pixel electrode PE will be described.

[0054] When a voltage is applied to the pixel electrode PE, the optical axis AX2 of the liquid crystal molecule 13b is tilted with respect to the Y direction in accordance with the magnitude of the voltage. On the other hand, the optical axis AX1 of the polymer network 13a is not tilted and is aligned with the Y direction even when a voltage is applied to the pixel electrode PE. In other words, the optical axis AX2 of the liquid crystal molecule 13b is tilted with respect to the optical axis AX1 of the polymer network 13a.

[0055] This causes a difference between the refractive index of the polymer network 13a and the refractive index of the liquid crystal molecules 13b. At this time, when the second drive circuit 50 emits light from the light emitters SL based on the light control signal, the light propagating within the display panel 10 is scattered. That is, in this case, the liquid crystal layer 13 is in a scattering state in which the light propagating within the display panel 10 is scattered. The light scattered by the liquid crystal layer 13 is radiated to the outside of the display panel 10 and is visible from both plate surfaces of the display panel 10.

[0056] Furthermore, the amount of light scattered by the liquid crystal layer 13 varies depending on the degree of scattering of the liquid crystal layer 13. The degree of scattering of the liquid crystal layer 13 is determined by the tilt of the liquid crystal molecules 13b, that is, the magnitude of the voltage applied to the pixel electrode PE. The magnitude of the voltage is determined based on the output grayscale value included in the pixel drive signal. The output grayscale value is calculated by the first drive circuit 40 for each of the multiple pixels P based on the input grayscale value of the image signal (details will be described later). The input grayscale value and the output grayscale value are values ​​(grayscale values) that indicate the grayscale of the pixel P. The input grayscale value is determined for each color of the pixel P. The color of the pixel P is determined by combining the colors of the three light emitters SL. In other words, the input grayscale value is determined for each color of the three light emitters SL, and the output grayscale value is calculated for each color of the three light emitters SL.

[0057] The first drive circuit 40 generates a pixel drive signal including an output gradation value calculated based on an input gradation value for each of the pixels P, and transmits the pixel drive signal to the pixels P. As a result, in each of the pixels P, a voltage according to the output gradation value is applied to the pixel electrode PE, and the liquid crystal molecules 13b corresponding to the pixel P tilt according to the magnitude of the output gradation value, changing the degree of scattering of the liquid crystal layer 13, thereby changing the amount of light emitted to the outside. The larger the output gradation value, the larger the voltage applied to the pixel electrode PE, and the greater the amount of light emitted to the outside, resulting in a higher luminance of the pixel P viewed from both plate surfaces (front surface 10a and back surface 10b) of the display panel 10.

[0058] Fig. 6 is a diagram showing the operation of the first drive circuit 40 and the second drive circuit 50 when an image is displayed on the display panel 10. Fig. 6 shows the operation of the first drive circuit 40 and the second drive circuit 50 per frame F. One frame F has a first sub-frame SF1, a second sub-frame SF2, and a third sub-frame SF3, in this order.

[0059] In the first sub-frame SF1, light of a first color (red) included in the image is emitted from the pixel P. Specifically, the first drive circuit 40 scans the multiple pixels P in the first scanning period TS1, selects the pixel P that is to emit light of the first color, and transmits a pixel drive signal corresponding to the first color to the selected pixel P. This causes the liquid crystal layer 13 corresponding to the selected pixel P to enter a scattering state according to the output gradation value corresponding to the first color. The voltage applied to the pixel electrode PE is held during the first emission period TL1, and is reset at the end of the first sub-frame SF1.

[0060] Moreover, the second driving circuit 50 causes the first light emitter 21a to emit light in the first light emission period TL1. The first light of the first color from the first light emitter 21a propagates through the display panel 10. Furthermore, the first light is reflected by the reflecting member 30 and propagates through the display panel 10 as the second light of the first color. As a result, in the liquid crystal layer 13 corresponding to the pixel P selected by the first driving circuit 40, the first light of the first color and the second light of the first color are scattered according to the degree of scattering of the liquid crystal layer 13 and emitted to the outside. That is, the light of the first color (the first light and the second light) having a gradation according to the output gradation value is emitted from the pixel P selected by the first driving circuit 40.

[0061] In the second sub-frame SF2, light of a second color (green) included in the image is emitted from the pixel P. Specifically, the first drive circuit 40 scans the multiple pixels P in the second scanning period TS2, selects the pixel P that is to emit light of the second color, and transmits a pixel drive signal corresponding to the second color to the selected pixel P. This causes the liquid crystal layer 13 corresponding to the selected pixel P to enter a scattering state according to the output gradation value corresponding to the second color. The voltage applied to the pixel electrode PE is held in the second emission period TL2, and is reset at the end of the second sub-frame SF2.

[0062] Moreover, the second driving circuit 50 causes the second light emitter 21b to emit light in the second light emission period TL2. The first light of the second color from the second light emitter 21b propagates through the display panel 10. Furthermore, the first light is reflected by the reflecting member 30 and propagates through the display panel 10 as the second light of the second color. As a result, in the liquid crystal layer 13 corresponding to the pixel P selected by the first driving circuit 40, the first light of the second color and the second light of the second color are scattered according to the degree of scattering of the liquid crystal layer 13 and emitted to the outside. That is, the light of the second color (the first light and the second light) having a gradation according to the output gradation value is emitted from the pixel P selected by the first driving circuit 40.

[0063] In the third sub-frame SF3, light of a third color (blue) included in the image is emitted from the pixel P. Specifically, the first drive circuit 40 scans the multiple pixels P in the third scanning period TS3, selects the pixel P that is to emit light of the third color, and transmits a pixel drive signal corresponding to the third color to the selected pixel P. This causes the liquid crystal layer 13 corresponding to the selected pixel P to enter a scattering state according to the output gradation value corresponding to the third color. The voltage applied to the pixel electrode PE is held during the third emission period TL3, and is reset at the end of the third sub-frame SF3.

[0064] Moreover, the second driving circuit 50 causes the third light emitter 21c to emit light in the third light emission period TL3. The first light of the third color from the third light emitter 21c propagates through the display panel 10. Furthermore, the first light is reflected by the reflecting member 30 and propagates through the display panel 10 as the second light of the third color. As a result, in the liquid crystal layer 13 corresponding to the pixel P selected by the first driving circuit 40, the first light of the third color and the second light of the third color are scattered according to the degree of scattering of the liquid crystal layer 13 and emitted to the outside. That is, the light of the third color (the first light and the second light) having a gradation according to the output gradation value is emitted from the pixel P selected by the first driving circuit 40.

[0065] The time of one frame F is determined as the time when the light obtained by combining the first, second, and third color lights emitted in one frame F is recognized by the human eye. That is, the human eye recognizes the light of the color and gradation obtained by combining the first, second, and third colors. Thus, an image is recognized by emitting the first, second, and third color lights from the multiple pixels P as described above. In this case, when the display area DA is viewed from one plate surface side of the display panel 10, the background on the other plate surface side of the display panel 10 is recognized as overlapping with the image.

[0066] In such a display device 1, the following phenomenon occurs. As described above, the first light propagates through the display panel 10 from the first side surface 10c to the second side surface 10d. As described above, the display panel 10 has elements such as the signal line Lb, the pixel electrode PE, and the switching element SW, and the light of the light emitter SL is scattered when it hits these elements. In other words, the first light of the light emitter SL is consumed by these elements.

[0067] Furthermore, when the liquid crystal layer 13 corresponding to a given pixel P is in the scattering state, a portion of the first light of the light emitter SL is emitted to the outside at the pixel P, and as a result, the amount of the first light of the light emitter SL propagating from the pixel P toward the second side surface 10d is reduced compared to when the liquid crystal layer 13 corresponding to the pixel P is in the transmitting state. In other words, the light of the light emitter SL is consumed by the liquid crystal layer 13 in the scattering state. When the first light is consumed in this manner, the amount of the first light of the light emitter SL propagating within the display panel 10 gradually decreases.

[0068] Moreover, the second light that is incident on the display panel 10 by the reflection of the first light by the reflective member 30 is also consumed by the elements that constitute the display panel 10 and the liquid crystal layer 13, which is in a scattering state, when propagating through the display panel 10 from the second side surface 10d to the first side surface 10c. In this manner, when the second light is consumed, the amount of the second light propagating through the display panel 10 gradually decreases.

[0069] FIG. 7 is a diagram showing the light amount of multiple pixels P aligned along a first direction W1 from the first side surface 10c toward the second side surface 10d. The vertical axis of FIG. 7 indicates the light amount. k on the horizontal axis of FIG. 7 indicates the positions of multiple pixels P aligned along the first direction W1. In this first embodiment, the first direction W1 is along the Y direction. k=1 corresponds to the position of pixel P located closest to the first side surface 10c in the first direction W1. k=α corresponds to the position of pixel P located closest to the second side surface 10d in the first direction W1. α indicates the number of multiple pixels P aligned along the first direction W1, and is, for example, 1080.

[0070] As described above, when the first light propagates through the display panel 10 in the first direction W1 from the first side surface 10c to the second side surface 10d, the first light is consumed by the elements constituting the display panel 10 and the liquid crystal layer 13, which is in a scattering state. Therefore, in FIG. 7, the first light amount RA1 of the first light decreases from the first side surface 10c to the second side surface 10d.

[0071] As described above, when the second light propagates through the display panel 10 in the first direction W1 from the second side surface 10d to the first side surface 10c, the second light is consumed by the elements constituting the display panel 10 and the liquid crystal layer 13, which is in a scattering state. Therefore, in FIG. 7, the second light amount RA2 of the second light decreases from the second side surface 10d toward the first side surface 10c.

[0072] In this embodiment, in the pixel P where k=α, the second light amount RA2 is greater than the first light amount RA1. This is because the light that exists inside the first substrate 11 before the light emitter SL emits the first light changes its traveling direction due to scattering that occurs when the first light is reflected, and is taken in as the second light amount RA2. In the pixel P where k=α, the second light amount RA2 may be equal to or less than the first light amount RA1.

[0073] 7 is an example, and varies depending on the elements constituting the display panel 10 and the degree of scattering of the liquid crystal layer 13. The degree of reduction in the first light amount RA1 and the second light amount RA2 shown in FIG 7 corresponds to the case where the output gradation values ​​corresponding to the multiple pixels P are equal to each other, for example.

[0074] 7 is a light amount that is a sum of the first light amount RA1 and the second light amount RA2. The total light amount SR is the sum of the first light amount RA1 and the second light amount RA2. The total light amount SR decreases and then increases when moving from the first side surface 10c toward the second side surface 10d along the first direction W1.

[0075] For example, when "white" is displayed with the same brightness in the entire display area DA based on an image signal, the input gradation values ​​corresponding to the pixels P are equal to each other, and generally, the output gradation values ​​corresponding to the pixels P are set to be equal to each other. Also, as described above, the total light amount SR shown in FIG. 7 decreases and then increases when moving from the first side surface 10c to the second side surface 10d along the first direction W1. Therefore, the luminance of the pixel P decreases and then increases when moving from the first side surface 10c to the second side surface 10d along the first direction W1. Therefore, the brightness of "white" displayed in the display area DA decreases and then increases when moving from the first side surface 10c to the second side surface 10d along the first direction W1. In other words, in this case, "white" is not displayed with the same brightness in the entire display area DA, and the desired display cannot be obtained.

[0076] Therefore, the first driving circuit 40 of the first embodiment of the present disclosure calculates the output grayscale value as described below.

[0077] Fig. 8 is a flowchart executed by the first driving circuit 40. For simplicity, a case will be described below in which "white" is displayed with the same brightness over the entire display area DA based on an image signal. In this case, as described above, the input gradation values ​​corresponding to the multiple pixels P are equal to each other. The first driving circuit 40 executes the flowchart of Fig. 8 upon acquiring the input gradation values ​​included in the image signal.

[0078] In step S1, the first driving circuit 40 calculates the first light amount RA1 for each of the multiple pixels P. The first driving circuit 40 first calculates the first light amount RA1 for the pixel P with k=1. The first light amount RA1 for the pixel P with k=1 is the amount of the first light when incident on the first side surface 10c. The amount of the first light when incident on the first side surface 10c is derived in advance by experiments, simulations, etc., and is stored in advance in a storage unit (not shown) of the first driving circuit 40. The first light amount RA1 for the pixel P with k=1 is determined to be the amount of the first light stored in the storage unit.

[0079] Next, the first driving circuit 40 calculates a first decrease rate (corresponding to a "first degree of light scattering") and a second decrease rate (corresponding to a "third degree of light scattering") which will be described next.

[0080] The first light propagating through the pixel P is consumed by scattering when it hits elements such as the signal line Lb, the pixel electrode PE, and the switching element SW of the display panel 10 as described above. The first light propagating through the pixel P is consumed by being absorbed by metal parts such as the switching element SW and glass parts such as the first substrate 11. In consideration of this, the first reduction rate corresponds to the rate of the first light that is reduced when propagating through the pixel P regardless of the presence or absence of display of each pixel P and the position of the pixel P. That is, the first reduction rate is determined by the structure of the pixel P, but is a constant value regardless of the position of the pixel P. In the first embodiment, the first reduction rate is set to a first predetermined rate (for example, 1%) (first reduction rate=first predetermined rate), and is equal to each other in multiple pixels P.

[0081] Also, when an arbitrary pixel P is in a display state, that is, when the liquid crystal layer 13 in the pixel P is in a scattering state, the light propagating through the pixel P is consumed by being scattered by the liquid crystal layer 13. The second decrease rate corresponds to a rate at which the first light propagating through the pixel P is decreased due to the liquid crystal layer 13 corresponding to the arbitrary pixel P being in a scattering state. The second decrease rate changes according to the degree of the scattering state of the liquid crystal layer 13. Specifically, the higher the degree of scattering of the liquid crystal layer 13 in the pixel P, that is, the higher the input grayscale value, the larger the second decrease rate becomes. In the first embodiment, the first driving circuit 40 calculates the second decrease rate by multiplying the input grayscale value corresponding to the pixel P by a second predetermined rate (for example, 5%) (second decrease rate=input grayscale value×second predetermined rate). The second predetermined rate is a constant value regardless of the position of the pixel P. The second predetermined rate and the above-mentioned first decrease rate are derived in advance by experiments, simulations, etc., and stored in the storage unit.

[0082] The first driving circuit 40 calculates the first decrease rate and the second decrease rate for the pixel P with k=1 as described above. The sum of the values ​​obtained by multiplying the calculated first decrease rate and the calculated second decrease rate by the first light amount RA1 of the pixel P with k=1 corresponds to the amount of light consumed as the first light in the pixel P with k=1. The amount of light obtained by subtracting the amount of light consumed as the first light in the pixel P with k=1 from the first light amount RA1 of the pixel P with k=1 corresponds to the first light amount RA1 of the pixel P with k=2.

[0083] Furthermore, the first driving circuit 40 calculates the first decrease rate and the second decrease rate in the pixel P where k=2 using the first light amount RA1 of the pixel P where k=2 as described above, and calculates the first light amount RA1 of the pixel P where k=3 based on the calculation result as described above. In this way, the first driving circuit 40 calculates the first light amount RA1 of the pixel P where k=i (i is an integer between 2 and α) for each of the multiple pixels P from k=1 to k=α using the first light amount RA1, the first decrease rate, and the second decrease rate of the pixel P where k=i-1.

[0084] That is, the first driving circuit 40 calculates a first light amount RA1 at the pixel P on the second side face 10d side of two pixels P aligned along a first direction W1 from the first side face 10c to the second side face 10d among the multiple pixels P, using a first decrease rate that occurs when the first light hits an element of the display panel 10 at the pixel P on the first side face 10c side of the two pixels P. Also, the first driving circuit 40 calculates a first light amount RA1 at the pixel P on the second side face 10d side of two pixels P aligned along the first direction W1 from the first side face 10c to the second side face 10d among the multiple pixels P, using a second decrease rate that changes based on the input gradation value at the pixel P on the first side face 10c side of the two pixels P.

[0085] The first light amount RA1 calculated by the first driving circuit 40 decreases from the first side surface 10c toward the second side surface 10d, as shown in FIG.

[0086] Next, the first driving circuit 40 calculates the second light amount RA2 in each of the multiple pixels P in step S2 shown in FIG. 8. The first driving circuit 40 first calculates the second light amount RA2 of the pixel P where k=α. The first driving circuit 40 calculates the second light amount RA2 of the pixel P where k=α by multiplying the first light amount RA1 of the pixel P where k=α by a predetermined coefficient. The predetermined coefficient is derived in advance by experiments, simulations, etc., and is stored in the storage unit in advance. As shown in FIG. 7, when the second light amount RA2 of the pixel P where k=α is larger than the first light amount RA1 of the pixel P where k=α, the predetermined coefficient is larger than 1.

[0087] Furthermore, the first driving circuit 40 calculates a third decrease rate (corresponding to a "second degree of light scattering") and a fourth decrease rate (corresponding to a "fourth degree of light scattering") which will be described next.

[0088] The third decrease rate corresponds to the rate of the second light consumed by the elements constituting the display panel 10. The third decrease rate is equal to the above-mentioned first decrease rate. That is, in the first embodiment, the third decrease rate is set to a first predetermined rate (e.g., 1%) (third decrease rate=first predetermined rate), and is equal to each other in a plurality of pixels P. Note that the third decrease rate may be set to a third predetermined rate different from the first predetermined rate.

[0089] The fourth decrease rate corresponds to the rate at which the second light propagating through the pixel P decreases due to the liquid crystal layer 13 corresponding to the arbitrary pixel P being in a scattering state. The fourth decrease rate changes according to the degree of the scattering state of the liquid crystal layer 13, similar to the above-mentioned second decrease rate. In the first embodiment, the first drive circuit 40 calculates the fourth decrease rate by multiplying the input gradation value corresponding to the pixel P by the second predetermined rate, similar to the above-mentioned second decrease rate (fourth decrease rate=input gradation value×second predetermined rate). Note that the fourth decrease rate may be a fourth predetermined rate different from the second predetermined rate instead of the second predetermined rate. When the above-mentioned third predetermined rate and fourth predetermined rate are used, the third predetermined rate and the fourth predetermined rate are derived in advance by experiments, simulations, etc., and stored in the storage unit.

[0090] The first driving circuit 40 calculates the third decrease rate and the fourth decrease rate for the pixel P where k=α as described above. The sum of the values ​​obtained by multiplying the calculated third decrease rate and the calculated fourth decrease rate by the second light amount RA2 of the pixel P where k=α corresponds to the amount of light consumed as the second light in the pixel P where k=α. The amount of light obtained by subtracting the amount of light consumed as the second light in the pixel P where k=α from the second light amount RA2 of the pixel P where k=α corresponds to the second light amount RA2 of the pixel P where k=α-1.

[0091] Furthermore, the first driving circuit 40 calculates the third decrease rate and the fourth decrease rate in the pixel P where k=α-1 using the second light amount RA2 of the pixel P where k=α-1 as described above, and calculates the second light amount RA2 of the pixel P where k=α-2 as described above based on the calculation result. In this way, the first driving circuit 40 calculates the second light amount RA2 of the pixel P where k=j (j is an integer between 1 and α-1) for each of the multiple pixels P from k=1 to k=α using the second light amount RA2, the third decrease rate, and the fourth decrease rate of the pixel P where k=j+1.

[0092] That is, the first driving circuit 40 calculates the second amount of light RA2 at the pixel P on the first side surface 10c side of two pixels P aligned along the first direction W1 from the first side surface 10c to the second side surface 10d among the multiple pixels P, using a third decrease rate that occurs when the second light hits an element of the display panel 10 at the pixel P on the second side surface 10d side of the two pixels P. Also, the first driving circuit 40 calculates the second amount of light RA2 at the pixel P on the first side surface 10c side of two pixels P aligned along the first direction W1 from the first side surface 10c to the second side surface 10d among the multiple pixels P, using a fourth decrease rate that changes depending on the input gradation value at the pixel P on the second side surface 10d side of the two pixels P.

[0093] The second light amount RA2 calculated by the first driving circuit 40 decreases from the second side surface 10d toward the first side surface 10c, as shown in FIG.

[0094] Furthermore, in step S3 shown in FIG. 8, the first driving circuit 40 calculates the total light amount SR for each of the multiple pixels P. The total light amount SR is the combined light amount of the first light amount RA1 and the second light amount RA2. The first driving circuit 40 calculates the total light amount SR by adding the second light amount RA2 to the first light amount RA1. As shown in FIG. 7, the total light amount SR decreases and then increases when moving from the first side surface 10c toward the second side surface 10d along the first direction W1. The minimum value of the total light amount SR is located on the second side surface 10d side from the center in the first direction W1.

[0095] 8, the first driving circuit 40 calculates an output gradation value based on the input gradation value and the total light amount SR for each of the multiple pixels P. Specifically, the first driving circuit 40 calculates a ratio of the total light amount SR for the multiple pixels P when the maximum value of the total light amount SR is set to "1" (ratio = total light amount SR of pixel P / maximum value of total light amount SR). Furthermore, the first driving circuit 40 calculates an output gradation value by dividing the input gradation value by the ratio calculated for each of the multiple pixels P (output gradation value = input gradation value / ratio).

[0096] Fig. 9 is a diagram showing an output gradation value T when the input gradation values ​​of multiple pixels P are equal to each other and the total light amount SR corresponds to the total light amount SR shown in Fig. 7. The horizontal axis shown in Fig. 9 is the same as the horizontal axis shown in Fig. 7. The vertical axis shown in Fig. 9 is the gradation value.

[0097] The output gradation value T calculated by the first driving circuit 40 as described above increases and then decreases when moving from the first side surface 10c to the second side surface 10d along the first direction W1. The total light amount SR shown in FIG. 7 decreases and then increases when moving from the first side surface 10c to the second side surface 10d along the first direction W1, as described above.

[0098] Due to such a relationship between the output gradation value T (FIG. 9) and the total light amount SR (FIG. 7), the luminance of the multiple pixels P becomes approximately equal to each other. In this case, "white" is displayed with approximately the same brightness over the entire display area DA, and the desired display can be obtained. In this manner, in the display device 1 having the display panel 10 into which light is incident from two opposite side surfaces (the first side surface 10c and the second side surface 10d), it is possible to equalize the luminance of the pixels P when the multiple input gradation values ​​corresponding to the multiple pixels P are equal to each other.

[0099] In this way, the first driving circuit 40 calculates output gradation values ​​corresponding to the multiple pixels P based on the combined light amount of the first light RA1 and the second light amount RA2 of the second light in each of the multiple pixels P, as well as the input gradation value of the image signal, and applies a voltage according to the output gradation value to each of the multiple pixels P.

[0100] In addition, when the input gradation values ​​corresponding to multiple pixels P are equal to each other, the first driving circuit 40 increases and then decreases the output gradation values ​​corresponding to multiple pixels P among the multiple pixels P that are arranged along a first direction W1 from the first side 10c to the second side 10d along the first direction W1.

[0101] <Second embodiment> Next, a display device 1 according to a second embodiment of the present disclosure will be described, mainly focusing on the differences from the display device 1 according to the above-described first embodiment.

[0102] 10 is a diagram showing a configuration of a display device 1 according to a second embodiment of the present disclosure. Unlike the display device 1 according to the first embodiment, the display device 1 of the second embodiment does not include a reflective member 30 and includes a second light source device 160.

[0103] The second light source device 160 is disposed on the side of the display panel 10. The second light source device 160 is disposed on the opposite side of the light source device 20 across the display panel 10. Specifically, the second light source device 160 is on the second side surface 10d side of the display panel 10 and faces the fourth YF side surface 15f of the second base material 15. The second light source device 160 emits light from the second side surface 10d side of the display panel 10 toward the first side surface 10c side. The second light source device 160 is fixed to the second base material 15 via a support 119.

[0104] The second light source device 160 is configured similarly to the above-described light source device 20. The second light source device 160 includes a light-emitting section 161 corresponding to the above-described light-emitting section 21, and a light-guiding section 162 corresponding to the above-described light-guiding section 22.

[0105] The light emitting unit 161 includes a first light emitter 161a corresponding to the first light emitter 21a, a second light emitter 161b corresponding to the second light emitter 21b, and a third light emitter 161c corresponding to the third light emitter 21c. When the first light emitter 161a, the second light emitter 161b, and the third light emitter 161c are described without distinction, they are simply referred to as "light emitter SL2."

[0106] The light emitter SL2 emits light toward the light guide section 162. The light of the light emitter SL2 corresponds to the light of the second light source device 160. Hereinafter, the light of the second light source device 160 (that is, the light of the light emitter SL2) will be referred to as third light.

[0107] The second light source device 160 is driven by the second drive circuit 50. The second drive circuit 50 drives the second light source device 160 by the above-mentioned field sequential method. The timing and color of light emitted by the second light source device 160 are the same as the timing and color of light emitted by the light source device 20.

[0108] The third light of the light emitter SL2 enters the light guide section 162, is diffused within the light guide section 162, and is emitted toward the fourth YF side surface 15f of the second base material 15 with the amount of light being uniformed.

[0109] The third light of the light emitter SL2 incident from the 4YF side surface 15f of the second base material 15 propagates through the display panel 10 from the second side surface 10d to the first side surface 10c of the display panel 10. Specifically, the third light of the light emitter SL2 is reflected by the front surfaces 11a, 12a, 14a, 15a and the rear surfaces 11b, 12b, 14b, 15b of the first substrate 11, the second substrate 12, the first base material 14, and the second base material 15, respectively, within the display panel 10, and propagates to the first side surface 10c.

[0110] Fig. 11 is a diagram showing the light amounts of a plurality of pixels P arranged along a first direction W1 from the first side surface 10c toward the second side surface 10d in a display device 1 according to a second embodiment of the present disclosure. The vertical and horizontal axes of Fig. 11 are the same as the vertical and horizontal axes of Fig. 7. Fig. 11 shows the first light amount RA1 of the first light shown in Fig. 7. Fig. 11 also shows the third light amount RA3 of the third light.

[0111] Like the first light, the third light is consumed by the elements constituting the display panel 10 and the liquid crystal layer 13, which is in a scattering state, when propagating through the display panel 10 in the first direction W1 from the second side surface 10d to the first side surface 10c. Thus, the third light amount RA3 of the third light decreases from the second side surface 10d to the first side surface 10c.

[0112] The degree of decrease in the first light amount RA1 and the third light amount RA3 shown in Fig. 11 is an example, and varies depending on the degree of scattering of the elements constituting the display panel 10 and the liquid crystal layer 13. The degree of decrease in the first light amount RA1 and the third light amount RA3 shown in Fig. 11 corresponds to the case where the output gradation values ​​corresponding to the multiple pixels P are equal to each other, for example.

[0113] Fig. 12 is a flowchart executed by the first driving circuit 40 of the display device 1 according to the second embodiment of the present disclosure. The first driving circuit 40 of the second embodiment calculates an output gradation value by executing the flowchart shown in Fig. 12 instead of the flowchart shown in Fig. 7.

[0114] For ease of explanation, the following will describe a case where "white" is displayed with the same brightness over the entire display area DA based on an image signal. In this case, as described above, the input gradation values ​​corresponding to the multiple pixels P are equal to each other.

[0115] 12, similar to step S1 in the first embodiment, the first driving circuit 40 calculates a first light amount RA1 for each of the multiple pixels P. The first light amount RA1 calculated by the first driving circuit 40 decreases from the first side surface 10c toward the second side surface 10d, as shown in FIG.

[0116] Next, the first driving circuit 40 calculates the third light amount RA3 in each of the multiple pixels P in step S12 shown in FIG. 12. The first driving circuit 40 first calculates the third light amount RA3 of the pixel P with k=α. The third light amount RA3 of the pixel P with k=α is the amount of the third light when it is incident on the second side surface 10d. The amount of the third light emitted by the light emitter SL2 is derived in advance by experiments, simulations, etc., and is stored in advance in the storage unit of the first driving circuit 40. The third light amount RA3 of the pixel P with k=α is determined to be the amount of the third light stored in the storage unit. The second light source device 160 has the same configuration as the light source device 20 described above. Therefore, the third light amount RA3 of the pixel P with k=α is equal to the first light amount RA1 of the pixel P with k=1.

[0117] Next, the first driving circuit 40 calculates a fifth decrease rate and a sixth decrease rate, which will be described next.

[0118] The fifth decrease rate corresponds to the rate of the third light consumed by the elements constituting the display panel 10. Therefore, the fifth decrease rate is equal to the above-mentioned first decrease rate. That is, in the second embodiment, the fifth decrease rate is set to a first predetermined rate (e.g., 1%) (the fifth decrease rate=the first predetermined rate), and is equal to each other for a plurality of pixels P. Note that the fifth decrease rate may be set to a fifth predetermined rate different from the first predetermined rate.

[0119] The sixth reduction rate corresponds to a rate at which the third light propagating through a pixel P is reduced due to the liquid crystal layer 13 corresponding to the pixel P being in a scattering state. The sixth reduction rate, like the second reduction rate described above, varies depending on the degree of scattering state of the liquid crystal layer 13. In the second embodiment, like the second reduction rate described above, the first driving circuit 40 calculates the sixth reduction rate by multiplying the input gradation value corresponding to the pixel P by the second predetermined rate (sixth reduction rate=input gradation value×second reduction rate). Note that the sixth reduction rate may be a sixth predetermined rate different from the second predetermined rate instead of the second predetermined rate. When the fifth and sixth predetermined rates described above are used, the fifth and sixth predetermined rates are derived in advance by experiments, simulations, etc., and stored in the storage unit.

[0120] The first driving circuit 40 calculates the fifth decrease rate and the sixth decrease rate for the pixel P where k=α as described above. The sum of the values ​​obtained by multiplying the calculated fifth decrease rate and the calculated sixth decrease rate by the third light amount RA3 of the pixel P where k=α corresponds to the amount of light consumed as the third light in the pixel P where k=α. Therefore, the amount of light obtained by subtracting the amount of light consumed as the third light in the pixel P where k=α from the third light amount RA3 of the pixel P where k=α corresponds to the third light amount RA3 of the pixel P where k=α-1.

[0121] Furthermore, the first driving circuit 40 calculates the fifth decrease rate and the sixth decrease rate in the pixel P where k=α-1 as described above using the third light amount RA3 of the pixel P where k=α-1, and calculates the third light amount RA3 of the pixel P where k=α-2 as described above based on the calculation result. In this way, the first driving circuit 40 calculates the third light amount RA3 of the pixel P where k=j (j is an integer between 1 and α-1) for each of the multiple pixels P from k=1 to k=α, using the third light amount RA3, the fifth decrease rate, and the sixth decrease rate of the pixel P where k=j+1.

[0122] The third light amount RA3 calculated by the first driving circuit 40 decreases from the second side surface 10d toward the first side surface 10c as shown in Fig. 11. As described above, the third light amount RA3 in the pixel P where k=α is equal to the first light amount RA1 in the pixel P where k=1. The third light amount RA3 and the first light amount RA1 are symmetrical with respect to a straight line parallel to the vertical axis of Fig. 11 and located at the center of the first direction W1. The first driving circuit 40 may execute the above steps S11 and S12 in parallel.

[0123] Furthermore, the first driving circuit 40 calculates a second total light amount SR2 in each of the multiple pixels P in step S13 shown in FIG. 12. The second total light amount SR2 is the total light amount of the first light amount RA1 and the third light amount RA3. The first driving circuit 40 calculates the second total light amount SR2 by adding the third light amount RA3 to the first light amount RA1. As shown in FIG. 11, the second total light amount SR2 decreases and then increases when moving from the first side surface 10c side to the second side surface 10d along the first direction W1. As described above, the third light amount RA3 and the first light amount RA1 are line-symmetric with each other, with the line parallel to the vertical axis of FIG. 11 and at the center of the first direction W1 as the axis of symmetry. Therefore, the minimum value of the second total light amount SR2 is at the center of the first direction W1. Also, the second total light amount SR2 is line-symmetric with the line parallel to the vertical axis of FIG. 11 and at the center of the first direction W1 as the axis of symmetry.

[0124] 12, the first driving circuit 40 calculates an output gradation value based on the input gradation value and the second total light amount SR2 for each of the multiple pixels P. Specifically, the first driving circuit 40 calculates a ratio of the second total light amount SR2 in the multiple pixels P when the maximum value of the second total light amount SR2 is set to "1" (ratio=second total light amount SR2 in pixel P / maximum value of second total light amount SR2). Furthermore, the first driving circuit 40 calculates an output gradation value by dividing the input gradation value by the ratio calculated for each of the multiple pixels P (output gradation value=input gradation value / ratio).

[0125] Fig. 13 is a diagram showing the output gradation value T2 when the input gradation values ​​of multiple pixels P are equal to each other and the second total light amount SR2 is the second total light amount SR2 shown in Fig. 11. The vertical and horizontal axes shown in Fig. 13 are the same as the vertical and horizontal axes shown in Fig. 9.

[0126] The output gradation value T2 calculated by the first driving circuit 40 as described above increases and then decreases when moving from the first side surface 10c toward the second side surface 10d along the first direction W1.

[0127] Due to such a relationship between the output gradation value T2 (FIG. 13) and the second total light amount SR2 (FIG. 11), the luminance of the multiple pixels P becomes approximately equal to each other. In this case, "white" is displayed with approximately the same brightness over the entire display area DA, and the desired display can be obtained. In this manner, in the display device 1 having the display panel 10 into which light is incident from two opposite side surfaces (the first side surface 10c and the second side surface 10d), it is possible to uniformize the luminance of the pixels P when the multiple input gradation values ​​corresponding to the multiple pixels P are equal to each other.

[0128] Thus, in the second embodiment, the first driving circuit 40 calculates output gradation values ​​corresponding to the multiple pixels P based on the combined light amount of the first light RA1 and the third light amount RA3 of the third light in each of the multiple pixels P, as well as the input gradation value of the image signal.

[0129] Although the preferred embodiment of the present disclosure has been described above, the present disclosure is not limited to such an embodiment. The contents disclosed in the embodiment are merely examples, and various modifications are possible within the scope of the present disclosure. Appropriate modifications made within the scope of the present disclosure also naturally belong to the technical scope of the present disclosure.

[0130] For example, in the first embodiment, the light source device 20 may be disposed facing one of the 4XL side surface 15c, the 4XR side surface 15d, and the 4YF side surface 15f of the second base material 15. The light source device 20 may also be disposed on the side of any one of the first substrate 11, the second substrate 12, and the first base material 14.

[0131] Furthermore, in the second embodiment, the third amount of light RA3 of the second light source device 160 at the pixel P where k=α may be different from the first amount of light RA1 of the light source device 20 at the pixel P where k=1.

[0132] Furthermore, other advantageous effects brought about by the aspects described in the above embodiments that are apparent from the description in this specification or that can be appropriately thought of by a person skilled in the art are naturally understood to be brought about by the present disclosure. [Explanation of symbols]

[0133] 1 Display device 10 Display Panel 13 Liquid crystal layer 10c 1st side 10d 2nd side 20 Light source device 30 Reflective material 40 First drive circuit (drive circuit) DA display area P pixels RA1 First light level RA2 2nd light intensity RA3 3rd light intensity SR total light amount W1 1st direction

Claims

1. a display panel having a display area overlapping a plurality of pixels arranged in a matrix in a plan view; a light source device disposed on a side of the display panel and configured to emit a first light from a first side surface of the display panel toward a second side surface opposite to the first side surface; a reflecting member disposed on the second side surface and configured to reflect the first light from the second side surface side toward the first side surface side as a second light; a drive circuit that calculates an output gradation value corresponding to the plurality of pixels based on a total amount of light of the first light and the second light amount of the second light in each of the plurality of pixels, and an input gradation value of an image signal, and applies a voltage according to the output gradation value to each of the plurality of pixels. Display device.

2. The display panel has a liquid crystal layer including a polymer dispersed liquid crystal. The display device according to claim 1 .

3. The drive circuit includes: calculating the first light amount at a pixel on the second side surface side of two pixels among the plurality of pixels arranged along a first direction from the first side surface toward the second side surface, using a degree of scattering of the first light generated when the first light hits an element of the display panel in the pixel on the first side surface side of the two pixels; The second light amount at the pixel on the first side surface side of the two pixels is calculated using a degree of scattering of the second light generated when the second light hits an element of the display panel at the pixel on the second side surface side of the two pixels. The display device according to claim 1 .

4. The drive circuit includes: calculating the first light amount at a pixel on the second side surface side of two pixels arranged along a first direction from the first side surface to the second side surface among the plurality of pixels, using a third light scattering degree that changes based on the input gradation value at the pixel on the first side surface side of the two pixels; The second light amount at the pixel on the first side surface side of the two pixels is calculated using a fourth light scattering degree at the pixel on the second side surface side of the two pixels, the fourth light scattering degree changing based on the input gradation value. The display device according to claim 1 .

5. a display panel having a display area overlapping a plurality of pixels arranged in a matrix in a plan view; a light source device disposed on a side of the display panel and configured to emit a first light from a first side surface of the display panel toward a second side surface opposite to the first side surface; a reflecting member disposed on the second side of the display panel and configured to reflect the first light toward the first side; a drive circuit that calculates output gradation values ​​corresponding to the plurality of pixels based on input gradation values ​​of an image signal, and applies a voltage corresponding to the output gradation value to each of the plurality of pixels; when the input gradation values ​​corresponding to the plurality of pixels are equal to each other, the drive circuit increases and then decreases the output gradation values ​​corresponding to a plurality of pixels among the plurality of pixels that are arranged along a first direction from the first side surface toward the second side surface along the first direction. Display device.

6. a display panel having a display area overlapping a plurality of pixels arranged in a matrix in a plan view; a light source device disposed on a side of the display panel and configured to emit a first light from a first side surface of the display panel toward a second side surface opposite to the first side surface; a second light source device disposed on a side of the display panel and configured to emit a third light from the second side surface toward the first side surface; a drive circuit that calculates an output gradation value corresponding to the plurality of pixels based on a total amount of light of the first light and a third amount of the third light in each of the plurality of pixels, and an input gradation value of an image signal, and applies a voltage corresponding to the output gradation value to each of the plurality of pixels. Display device.

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