Indication device

Abstract

To provide a display device in which, when a plurality of pixels has a same gradation value, brightness of a display region to display an image is homogeneous.SOLUTION: A display device 1 includes a display panel 20 including a display region DA with a plurality of pixels G, a light source device 40 to emit emission light from an emission region SA to the display panel 20, a dimming panel 30 to control brightness of the emission light, and a driving circuit 10. When, among the pixels G, a first pixel corresponding to a first emission range SA1 and a second pixel corresponding to a second emission range SA2 have a same gradation value, the driving circuit 10 makes transmittance of a second dimming range PA2 for the second pixel higher than transmittance of a first dimming range PA1 for the first pixel in a dimming region.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] A configuration is known in which a dimming panel is provided between a liquid crystal display panel and a light source device to further enhance the contrast of an image (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the light-emitting region of a light source device that emits light to a liquid crystal display panel, due to the structure of the light source device, the brightness may not be uniform. In this case, even if the gradation values of all pixels are the same in the display region of the liquid crystal display panel that displays an image, the brightness may not be uniform.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to equalize the brightness of a display region that displays an image when the gradation values of a plurality of pixels are the same in a display device.

Means for Solving the Problems

[0006] A display device according to one aspect of the present disclosure includes a display panel having a display area having a plurality of pixels; a light source device that emits light toward the display panel from an emission area that overlaps with the display area in a plan view; a dimming panel disposed between the display panel and the light source device, which adjusts the brightness of the emitted light emitted from the emission area in a dimming area that overlaps with the display area in a plan view; and a drive circuit that drives the dimming panel, wherein the emission area has a first emission range and a second emission range, and in the plurality of pixels, if the gradation value of a first pixel corresponding to the first emission range is equal to the gradation value of a second pixel corresponding to the second emission range among the plurality of pixels, the drive circuit makes the transmittance of the second dimming range corresponding to the second pixel higher than the transmittance of the first dimming range corresponding to the first pixel in the dimming area. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows the configuration of a display device according to the first embodiment of this disclosure. [Figure 2] Figure 2 is a side view of the display device. [Figure 3] Figure 3 shows the circuit configuration of the display panel. [Figure 4] Figure 4 is a cross-sectional view of the display panel and the dimming panel. [Figure 5] Figure 5 is a plan view of the display area. [Figure 6] Figure 6 is a cross-sectional view of the display device. [Figure 7] Figure 7 shows the luminance distribution of the emission region in a planar view. [Figure 8] Figure 8 shows the luminance distribution in the emission region of a cross-section of a light source device along line AA shown in Figure 7. [Figure 9] Figure 9 is a block diagram of the signal processing circuit. [Figure 10] Figure 10 shows a portion of the brightness adjustment data. [Figure 11] Figure 11 is a flowchart showing the actions performed by the drive circuit. [Figure 12] Figure 12 shows the values ​​that the drive circuit calculates when generating dimming sub-gradation data and display sub-gradation data. [Figure 13] Figure 13 shows a portion of the brightness of a display area when the grayscale values ​​of grayscale data in multiple pixels are equal to each other. [Figure 14] Figure 14 shows a part of the brightness of a display area in a modified example of the first embodiment, where the grayscale values ​​of grayscale data in multiple pixels are equal to each other. [Figure 15] Figure 15 shows the luminance distribution in the emission region of a cross-section of a light source device along line AA shown in Figure 7, in the second embodiment. [Figure 16] Figure 16 shows a portion of the brightness adjustment data for the second embodiment. [Modes for carrying out the invention]

[0008] The embodiments of this disclosure will be described below with reference to the drawings. This disclosure is not limited to the embodiments described below. Furthermore, the components described below include those that are readily conceivable to those skilled in the art, and those that are substantially the same. In addition, the components described below can be combined as appropriate.

[0009] Furthermore, the disclosure is merely an example, and modifications that a person skilled in the art could easily conceive of while maintaining the spirit of the invention are naturally included within the scope of this disclosure. In addition, the drawings may schematically represent the width, thickness, shape, etc. of each part in order to clarify the explanation, but these are merely examples and do not limit the interpretation of this disclosure. In addition, in this specification and each drawing, elements similar to those described above in previously shown drawings are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0010] The X and Y directions shown in the drawings correspond to directions parallel to the main surface of the substrate included in the display device 1. The +X side and -X side in the X direction, and the +Y side and -Y side in 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 in the Z direction corresponds to the front side where an image is displayed in the display device 1, and the -Z side in the Z direction corresponds to the back side of the display device 1. Also, in this specification, "plan view" means viewing the display device 1 from the +Z side toward the -Z side along the Z direction. Note that the directions of X, Y, and Z are merely examples, and the present disclosure is not limited to these directions.

[0011] <First Embodiment> FIG. 1 is a diagram showing the configuration of a display device 1 according to a first embodiment of the present disclosure. FIG. 2 is a side view of the display device 1. The display device 1 includes a drive circuit 10, a display panel 20, a dimming panel 30, and a light source device 40.

[0012] The drive circuit 10 acquires an image signal output from an external device 2 and controls the display panel 20, the dimming panel 30, and the light source device 40. The image signal is a signal having data for causing the display panel 20 to display an image (details will be described later).

[0013] The drive circuit 10 includes a signal processing circuit 11, a first signal output circuit 12, a first scanning circuit 13, a second signal output circuit 14, a second scanning circuit 15, and a light source control circuit 16.

[0014] Based on the image signal, the signal processing circuit 11 generates display sub-pixel signals, dimming sub-pixel signals, and light source control signals, which will be described later, and outputs the display sub-pixel signals, dimming sub-pixel signals, and light source control signals to the first signal output circuit 12, the second signal output circuit 14, and the light source control circuit 16. Also, the signal processing circuit 11 outputs a clock signal for synchronizing the first signal output circuit 12, the first scanning circuit 13, the second signal output circuit 14, the second scanning circuit 15, and the light source control circuit 16 to each of the first signal output circuit 12, the first scanning circuit 13, the second signal output circuit 14, the second scanning circuit 15, and the light source control circuit 16.

[0015] The first signal output circuit 12 and the first scanning circuit 13 control the display panel 20 based on the display sub-pixel signals. The second signal output circuit 14 and the second scanning circuit 15 control the dimming panel 30 based on the dimming sub-pixel signals. The light source control circuit 16 controls the light source device 40 based on the light source control signal. The details of the signal processing circuit 11, the first signal output circuit 12, the first scanning circuit 13, the second signal output circuit 14, the second scanning circuit 15, and the light source control circuit 16 will be described later.

[0016] As shown in FIG. 2, the display panel 20, the dimming panel 30, and the light source device 40 are arranged in this order from the +Z side to the -Z side. That is, the dimming panel 30 is arranged between the display panel 20 and the light source device 40 in the Z direction.

[0017] The display panel 20 is a transmissive liquid crystal display. Note that the display panel 20 may be, for example, an organic EL display or an inorganic EL display. As shown in FIG. 1, the front surface of the display panel 20 has a display area DA where an image is displayed.

[0018] The display panel 20 has a plurality of display sub-pixels Sd arranged in a matrix along the X direction and the Y direction in the display area DA.

[0019] FIG. 3 is a diagram showing the circuit configuration of the display panel 20. The plurality of display sub-pixels Sd are driven by the first signal output circuit 12 and the first scanning circuit 13.

[0020] The first signal output circuit 12 outputs a plurality of display sub-pixel signals to the plurality of display sub-pixels Sd (details will be described later). The first signal output circuit 12 and the plurality of display sub-pixels Sd are electrically connected via a plurality of first signal lines Lb1 extending along the Y direction.

[0021] The first scanning circuit 13 scans multiple display subpixels Sd in synchronization with the output of the display subpixel signal by the first signal output circuit 12. The first scanning circuit 13 and the multiple display subpixels Sd are electrically connected via multiple first scanning lines Lc1 extending along the X direction.

[0022] The display panel 20 includes a switching element SW, a sub-pixel electrode PE, a common electrode CE, a liquid crystal capacitance LC, and a retaining capacitance CS, each of which is a sub-display pixel Sd.

[0023] The switching element SW is composed of, for example, a thin-film transistor (TFT). In the switching element SW, the source electrode and the first signal line Lb1 are electrically connected, and the gate electrode and the first scan line Lc1 are electrically connected.

[0024] The sub-pixel electrode PE is connected to the drain electrode of the switching element SW. Multiple common electrodes CE are arranged to correspond to multiple first scan lines Lc1. The sub-pixel electrode PE and common electrode CE are translucent.

[0025] The liquid crystal capacitance LC is the capacitive component of the liquid crystal material in the liquid crystal layer 22, which will be described later, located between the sub-pixel electrode PE and the common electrode CE. The retained capacitance CS is located between an electrode at the same potential as the common electrode CE and an electrode at the same potential as the sub-pixel electrode PE.

[0026] Figure 4 is a cross-sectional view of the display panel 20 and the dimming panel 30. The display subpixel Sd of the display panel 20 further comprises a first substrate 21, a liquid crystal layer 22, and a second substrate 23. The first substrate 21, the liquid crystal layer 22, and the second substrate 23 are all light-transmitting and are arranged in this order from the -Z side to the +Z side.

[0027] The first substrate 21 is rectangular in plan view and one is provided for each of the multiple display subpixels Sd. The first substrate 21 houses a signal processing circuit 11, a first signal output circuit 12, and a first scanning circuit 13 (Figure 3).

[0028] Furthermore, the switching element SW, the first signal line Lb1, and the first scan line Lc1 are arranged on the main surface 21a on the +Z side of the first substrate 21 (not shown in Figure 4). In addition, a common electrode CE and a sub-pixel electrode PE are arranged on the main surface 21a, with an insulating layer IL in between. Thus, the sub-pixel electrode PE and the common electrode CE are arranged on the first substrate 21, and the display panel 20 is a transverse electric field type liquid crystal display.

[0029] The liquid crystal layer 22 is composed of multiple liquid crystal molecules. In the Z direction, the liquid crystal layer 22 is located between two alignment films AL. The orientation of the liquid crystal molecules is restricted by the two alignment films AL.

[0030] The second substrate 23 is rectangular in plan view and one is provided for each of the multiple display subpixels Sd. A color filter CF, a light-shielding layer SM, and an overcoat layer OC are arranged on the back side of the second substrate 23.

[0031] The color filter CF is rectangular in plan view and one is placed for each of the multiple display subpixels Sd. The color filter CF is light-transmitting, and the peak of the spectrum of light it transmits is predetermined.

[0032] The peak in this spectrum is one of three spectral peaks corresponding to three distinct colors. These three colors are red, green, and blue, but it goes without saying that the number and types of colors are not limited to these. Hereinafter, the color corresponding to the peak in the spectrum of light transmitted by the color filter CF will be referred to as the color of the color filter CF. The color of the color filter CF corresponds to the color of the display sub-pixel Sd.

[0033] Furthermore, the first signal line Lb1 located on the first substrate 21 is positioned to coincide with the boundary of the color filter CF of two adjacent display subpixels Sd in the X direction when viewed from above. In other words, the first signal line Lb1 is positioned to coincide with the boundary of two adjacent display subpixels Sd in the X direction when viewed from above.

[0034] Furthermore, the first scan line Lc1 located on the first substrate 21 is positioned to coincide with the boundary of the color filter CF of two adjacent display subpixels Sd in the Y direction in a plan view. In other words, the first scan line Lc1 is positioned to coincide with the boundary of two adjacent display subpixels Sd in the Y direction in a plan view.

[0035] The light-shielding layer SM has light-shielding properties and partitions multiple display subpixels Sd. In other words, the light-shielding layer SM is located at a position that overlaps with the boundaries of multiple adjacent display subpixels Sd in the X and Y directions. Furthermore, the light-shielding layer SM overlaps with the first signal line Lb1 and the first scan line Lc1 in the Z direction.

[0036] The overcoat layer OC is positioned between the color filter CF and the alignment film AL, and suppresses the penetration of pigments contained in the color filter CF into the liquid crystal layer 22.

[0037] Furthermore, the display panel 20 also includes a first polarizing plate 24 located on the back side of the first substrate 21, and a second polarizing plate 25 located on the front side of the second substrate 23.

[0038] The first polarizing plate 24 has a transmission axis perpendicular to the Z direction. The second polarizing plate 25 has a transmission axis perpendicular to the transmission axis of the first polarizing plate 24 and the Z direction.

[0039] Figure 5 is a plan view of the display area DA. The multiple display subpixels Sd have multiple first display subpixels Sd1, multiple second display subpixels Sd2, and multiple third display subpixels Sd3. In the first display subpixels Sd1, second display subpixels Sd2, and third display subpixels Sd3, the color of the color filter CF, i.e., the color of the display subpixel Sd, is different from each other. The color of the first display subpixel Sd1 is red. The color of the second display subpixel Sd2 is green. The color of the third display subpixel Sd3 is blue. Needless to say, the color of the display subpixel Sd is not limited to these; it is sufficient that the colors of the first display subpixel Sd1, second display subpixel Sd2, and third display subpixel Sd3 are different from each other. Also, when describing common matters without distinguishing between the first display subpixel Sd1, second display subpixel Sd2, and third display subpixel Sd3, they may simply be referred to as "display subpixel Sd".

[0040] In the display area DA, multiple display subpixels Sd are arranged in the X direction in a repeating order: a column of multiple first display subpixels Sd1 along the Y direction, a column of multiple second display subpixels Sd2 along the Y direction, and a column of third display subpixels Sd3 along the Y direction. In other words, in the display area DA, multiple sets of display subpixels CSd, each consisting of one first display subpixel Sd1, one second display subpixel Sd2, and one third display subpixel Sd3 aligned along the X direction, are arranged along both the X and Y directions.

[0041] This pair of display subpixels CSd constitutes one pixel G. That is, in the display area DA, multiple pixels G are arranged along both the X and Y directions. In other words, in the display area DA, the arrangement of multiple display subpixels Sd is a so-called stripe arrangement. However, it goes without saying that the arrangement of multiple display subpixels Sd is not limited to a stripe arrangement.

[0042] Next, the operation of the display panel 20 will be described. First, the case where the display panel 20 uses a normally black method and black is displayed in the display area DA will be described. In this case, the drive circuit 10 does not drive the display subpixel Sd, and no electric field is generated in the liquid crystal layer 22. As a result, the orientation of the liquid crystal molecules is restricted by the alignment film AL.

[0043] Light emitted from the light source device 40 enters the display panel 20 from the back side of the first polarizing plate 24 via the dimming panel 30. The light transmitted through the first polarizing plate 24 is linearly polarized, having a polarization axis parallel to the transmission axis of the first polarizing plate 24. The light transmitted through the first polarizing plate 24 then passes through the first substrate 21 and enters the liquid crystal layer 22.

[0044] When the orientation of the liquid crystal molecules is restricted by the alignment film AL, the polarization axis of light does not rotate in the liquid crystal layer 22. Light that has passed through the liquid crystal layer 22 passes through the second substrate 23 and is incident on the second polarizing plate 25.

[0045] The polarization axes of the light transmitted through the liquid crystal layer 22 and the second substrate 23 are orthogonal to the transmission axis of the second polarizer 25, and the light transmitted through the liquid crystal layer 22 does not pass through the second polarizer 25. In other words, when the orientation of the liquid crystal molecules is restricted by the alignment film AL, the light emitted from the light source device 40 does not pass through the display subpixel Sd. As a result, black is displayed in the display area DA.

[0046] Next, the operation of the display panel 20 when an image is displayed in the display area DA will be described. In this case, a display subpixel signal is output from the first signal output circuit 12 to multiple display subpixels Sd. The display subpixel signal includes display sub-gradation data indicating the gradation of the display subpixel Sd.

[0047] The first scanning circuit 13 scans the display sub-pixel Sd, which operates the switching element SW and transmits a display sub-pixel signal to the sub-pixel electrode PE. This creates a potential difference between the common electrode CE and the sub-pixel electrode PE, and consequently, an electric field in the liquid crystal layer 22, which changes the orientation of the liquid crystal molecules. The orientation of the liquid crystal molecules is determined by the display sub-gradation data. Specifically, the orientation of the polarization axis of the light transmitted through the liquid crystal layer 22 changes according to the gradation value of the display sub-gradation data. Light that has been transmitted through the liquid crystal layer 22 and whose polarization axis is not perpendicular to the polarization axis of the second polarizer 25 is transmitted through the second polarizer 25.

[0048] The brightness of the light transmitted through the second polarizing plate 25 corresponds to the brightness of the gradation value of the display sub-gradation data. In this way, the orientation of the liquid crystal molecules is adjusted by the display sub-pixel signal, thereby adjusting the light transmittance of the liquid crystal layer 22, that is, the brightness of the light transmitted through the liquid crystal layer 22. Furthermore, the light transmitted through the color filter CF on the first substrate 21 has a color corresponding to the color of the color filter CF. In other words, the light transmitted through the second polarizing plate 25 has a color corresponding to the color of the color filter CF, and its brightness is adjusted.

[0049] In each of the multiple display subpixels Sd, the color of the color filter CF, i.e., the color of the light transmitted through the second polarizer 25, corresponds to the color of the display subpixel Sd. Furthermore, in each of the multiple display subpixels Sd, the brightness of the light transmitted through the second polarizer 25, i.e., the light transmittance of the display subpixel Sd, is adjusted according to the gradation value of the display sub-gradation data. As a result, an image based on the image signal is displayed in the display area DA. Note that the display panel 20 may also use a normally white method.

[0050] The dimming panel 30 adjusts the brightness of the light emitted from the light source device 40 and incident on the display panel 20. In other words, the dimming panel 30 adjusts the light transmittance in the Z direction. As shown in Figure 4, the dimming panel 30 is bonded to the display panel 20 via a light-transmitting adhesive layer OCA. The dimming panel 30 adjusts the brightness of the light by adjusting the light transmittance in the dimming region PA shown in Figure 1. Specifically, the dimming panel 30 adjusts the brightness of the light emitted from the light source device 40. In a plan view, the dimming region PA overlaps with the display region DA.

[0051] As shown in Figure 1, the dimming panel 30 has a plurality of dimming sub-pixels Sp arranged in a matrix along the X and Y directions in the dimming region PA.

[0052] Each of the multiple dimming sub-pixels Sp is superimposed on a plurality of display sub-pixels Sd in a planar view, and is configured similarly to the display sub-pixels Sd, except that the dimming sub-pixels Sp have the same color as each other. In other words, the dimming panel 30 is equipped with a switching element SW, a sub-pixel electrode PE, a common electrode CE, a liquid crystal capacitance LC, and a retaining capacitance CS for each of the plurality of dimming sub-pixels Sp. Furthermore, the plurality of dimming sub-pixels Sp are driven by a second signal output circuit 14 and a second scanning circuit 15.

[0053] The second signal output circuit 14 outputs multiple dimming sub-pixel signals to multiple dimming sub-pixels Sp (details will be described later). The second signal output circuit 14 and the multiple dimming sub-pixels Sp are electrically connected via multiple second signal lines Lb2 extending along the Y direction.

[0054] The second scanning circuit 15 scans multiple dimming sub-pixels Sp in synchronization with the output of the dimming sub-pixel signal from the second signal output circuit 14. The second scanning circuit 15 and the multiple dimming sub-pixels Sp are electrically connected via multiple second scanning lines Lc2 extending along the X direction.

[0055] Furthermore, as shown in Figure 4, the dimming panel 30 is configured similarly to the display panel 20, except that it does not have a color filter CF and an overcoat layer OC. In other words, the dimming panel 30 comprises a third substrate 31, a liquid crystal layer 32, a fourth substrate 33, an alignment film AL, a light-shielding layer SM, a third polarizer 34, and a fourth polarizer 35, corresponding to the first substrate 21, second substrate 23, liquid crystal layer 22, alignment film AL, light-shielding layer SM, first polarizer 24, and second polarizer 25 of the display panel 20, respectively. The transmission axis of the first polarizer 24 and the transmission axis of the fourth polarizer 35 are parallel to each other. Note that the display device 1 does not need to include either the first polarizer 24 or the fourth polarizer 35.

[0056] With the dimming panel 30 configured in this way, as shown in Figure 1, multiple dimming sub-pixels Sp are arranged in a matrix along the X and Y directions in the dimming region PA, as described above. In addition, in the dimming region PA, one set of dimming sub-pixels CSp, which consists of one set of display sub-pixels CSd and three dimming sub-pixels Sp superimposed in a plan view, is arranged along the X and Y directions. Each of the multiple sets of dimming sub-pixels CSp superimposes multiple pixels G in a plan view.

[0057] Next, the operation of the dimming panel 30 will be described. The dimming panel 30 is configured similarly to the display panel 20, except that it does not have a color filter CF and an overcoat layer OC, as described above, and operates similarly to the display panel 20. The light emitted from the light source device 40 is incident on the third polarizing plate 34.

[0058] If the dimming panel 30 does not transmit light (i.e., the light transmittance is 0%), the drive circuit 10 does not drive the dimming sub-pixel Sp, and the dimming panel 30 operates in the same way as when the display panel 20 displays black.

[0059] On the other hand, when the dimming panel 30 transmits light (i.e., when the light transmittance exceeds 0%), a dimming sub-pixel signal is output to multiple dimming sub-pixels Sp via the second signal output circuit 14. The dimming sub-pixel signal includes dimming sub-gradation data indicating the gradation of the dimming sub-pixel Sp, as will be described later.

[0060] The dimming sub-pixel Sp is scanned by the second scanning circuit 15, causing it to operate in the same way as the display sub-pixel Sd described above. In other words, the orientation of the polarization axis of the light transmitted through the liquid crystal layer 32 changes according to the gradation value of the dimming sub-gradation data. In this way, the orientation of the liquid crystal molecules is adjusted by the dimming sub-pixel signal, thereby adjusting the light transmittance of the liquid crystal layer 32 and, consequently, the brightness of the light transmitted through the liquid crystal layer 32, i.e., the light transmittance of the dimming panel 30. The light transmitted through the dimming panel 30 is incident on the display panel 20.

[0061] As shown in Figures 2 and 4, the light source device 40 is positioned on the back side of the dimming panel 30 and emits light toward the dimming panel 30 and the display panel 20. The light source device 40 emits light from the emission area SA shown in Figure 1. In a plan view, the emission area SA overlaps with the dimming area PA and the display area DA.

[0062] Figure 6 is a cross-sectional view of the display device 1. The display device 1 further comprises a housing 50 that is open on the +Z side and supports the display panel 20 and the dimming panel 30 at its periphery.

[0063] The light source unit 40 is located inside the housing 50. The light source unit 40 is a direct-lit backlight unit. The light source unit 40 comprises an electrical circuit board 41, a frame 42, and a diffusion panel 43.

[0064] The electrical circuit board 41 is rectangular in plan view and is located on the inner bottom surface of the housing 50. Multiple light-emitting elements 44 are mounted on the main surface 41a of the electrical circuit board 41 that overlaps with the emission area SA in plan view, and the multiple light-emitting elements 44 are covered with an overcoat layer 45 that protects the light-emitting elements 44.

[0065] The light-emitting element 44 is a self-emitting element, such as a light-emitting diode (LED). Multiple light-emitting elements 44 are arranged in a grid pattern in plan view. Specifically, in plan view, the multiple light-emitting elements 44 are arranged in a matrix along the X and Y directions, respectively, on the central side of the periphery of the main surface 41a.

[0066] Furthermore, the multiple light-emitting elements 44 are evenly distributed across the entire main surface 41a. In other words, the number of light-emitting elements 44 per unit area of ​​the main surface 41a is the same across the entire main surface 41a. Specifically, the multiple light-emitting elements 44 are arranged at equal intervals along the X and Y directions. The light-emitting elements 44 emit light towards the +Z side.

[0067] The frame 42 supports the peripheral edge of the diffusion panel 43 inside the housing 50, on the +Z side of the electrical circuit board 41. The frame 42 is positioned on the inner surface of the side wall of the housing 50 and laterally to the electrical circuit board 41. In other words, in a plan view, the peripheral edge of the electrical circuit board 41 is separated from the side wall of the housing 50 and the frame 42. In a plan view, the electrical circuit board 41 may be in contact with the side wall of the housing 50 or the frame 42, but the light-emitting element 44 is positioned on the main surface 41a, separated from the side wall of the housing 50 and the frame 42.

[0068] The diffusion panel 43 diffuses and transmits the light emitted from the light-emitting element 44. On the front surface of the diffusion panel 43, the area from the center of the part supported by the housing 50 corresponds to the emission region SA.

[0069] The light source control circuit 16 controls the multiple light-emitting elements 44 based on the light source control signal so that the light intensity of each element is equal to that of the other. As a result, the brightness of the light-emitting elements 44, i.e., the brightness of the light emitted by the multiple light-emitting elements 44, is equal to that of the other. The light emitted from the light-emitting elements 44 is emitted from the emission area SA towards the back of the dimming panel 30 as emitted light.

[0070] Figure 7 shows the luminance distribution of the emission region SA in a plan view. Figure 7 shows the luminance distribution of the emission region SA when the luminances of multiple light-emitting elements 44 are equal to each other.

[0071] The emission region SA has a first emission range SA1 and a second emission range SA2. The brightness of the emitted light in the second emission range SA2 is weaker than the brightness of the emitted light in the first emission range SA1. In other words, the brightness of the second emission range SA2 is lower than the brightness of the first emission range SA1.

[0072] The first emission range SA1 is located in the center of the emission region SA in a plan view. This is because, as described above, multiple light-emitting elements 44, each having the same light intensity, are arranged in a matrix at equal intervals along the X and Y directions, and the brightness is almost constant at its highest value in the center of the emission region SA in a plan view.

[0073] The second emission range SA2 is located closer to the periphery of the emission region SA than the first emission range SA1 in a plan view. Specifically, the second emission range SA2 is adjacent to the first emission range SA1 and lies between the periphery of the first emission range SA1 and the periphery of the emission region SA. In the second emission range SA2, the brightness decreases from the center to the periphery of the emission region SA.

[0074] The reason for this is that, as described above, in a plan view, the periphery of the electrical circuit board 41 is separated from the side wall and frame 42 of the housing 50, and the number of light-emitting elements 44 arranged per unit area in the range corresponding to the second emission range SA2 is less than the number of light-emitting elements 44 arranged per unit area in the range corresponding to the first emission range SA1. Furthermore, in the second emission range SA2, the light-emitting elements 44 are located towards the center of the emission region SA, and the amount of light from the light-emitting elements 44 decreases from the center towards the periphery of the emission region SA.

[0075] Figure 8 shows the luminance distribution of the emission region SA in a cross-section of the light source device 40 along line AA shown in Figure 7. In Figure 8, the horizontal axis represents the X coordinate of the emission region SA, and the vertical axis represents the luminance of the emission region SA as a percentage, with the highest luminance in the emission region SA defined as 100%.

[0076] As shown in Figure 8, in the first emission range SA1, the luminance in the emission region SA remains almost constant at its highest value (i.e., 100%). The luminance changes continuously from the first emission range SA1 to the second emission range SA2. The luminance at the inner periphery of the second emission range SA2 is less than 100%, and the luminance decreases from the center to the periphery of the emission region SA, with the luminance at the outer periphery of the second emission range SA2 being 25%.

[0077] Furthermore, in the cross-section of the light source device 40 along the straight line intersecting the AA line in a plan view, the brightness is almost constant at its highest value in the first emission range SA1, while in the second emission range SA2, the brightness decreases from the center to the periphery of the emission area SA.

[0078] Next, the configuration of the signal processing circuit 11 will be described. Figure 9 is a block diagram of the signal processing circuit 11. The signal processing circuit 11 includes a storage unit 11a, an acquisition unit 11b, a first correction unit 11c, a light transmittance calculation unit 11d, a dimming sub-gradation data generation unit 11e, a display sub-gradation data generation unit 11f, a second correction unit 11g, and an output unit 11h.

[0079] The memory unit 11a has brightness adjustment data stored in advance to adjust the brightness. As described above, in the output area SA, the brightness of the second output range SA2 is lower than the brightness of the first output range SA1. Therefore, when the gradation values ​​of the gradation data of multiple pixels G are equal to each other, the brightness of the range of the display area DA corresponding to the second output range SA2 will be lower than the brightness of the range of the display area DA corresponding to the first output range SA1, and the desired brightness cannot be obtained.

[0080] Therefore, as explained below, the brightness adjustment data is defined such that the brightness of the display area DA becomes uniform when the gradation values ​​of the gradation data in multiple pixels G are equal, corresponding to the brightness distribution of the output area SA shown in Figures 7 and 8.

[0081] Specifically, the drive circuit 10 adjusts the light transmittance of the dimming area PA using brightness adjustment data. By adjusting the light transmittance of the dimming area PA using brightness adjustment data, the drive circuit 10 adjusts the light transmittance of the second dimming area PA2, which corresponds to the second pixel, to be higher than the light transmittance of the first dimming area PA1, which corresponds to the first pixel, in the dimming area PA, when the gradation value of the pixel G corresponding to the first emission range SA1 (hereinafter referred to as the first pixel) and the gradation value of the pixel G corresponding to the second emission range SA2 (hereinafter referred to as the second pixel) among the multiple pixels G are equal.

[0082] The first pixel is one of several pixels G in the display area DA that overlaps with the first emission range SA1 in a plan view, and there are multiple first pixels. The second pixel is one of several pixels G in the display area DA that overlaps with the second emission range SA2 in a plan view, and there are multiple second pixels.

[0083] The first dimming range PA1 is the range of the dimming region PA that overlaps with the first emission range SA1 in a plan view, and is located in the center of the dimming region PA. Therefore, multiple first pixels overlap with the first dimming range PA1 and the first emission range SA1 in a plan view.

[0084] The second dimming range PA2 is the range of the dimming region PA that overlaps with the second emission range SA2 in a plan view, and is located closer to the periphery of the dimming region PA than the first dimming range PA1. Specifically, the second dimming range PA2 lies between the periphery of the first dimming range PA1 and the periphery of the dimming region PA. Therefore, multiple second pixels overlap with the second dimming range PA2 and the second emission range SA2 in a plan view.

[0085] In the brightness adjustment data, the correction ratio for the first dimming range PA1 corresponding to the first emission range SA1 is constant and smaller than the correction ratio for the second dimming range PA2 corresponding to the second emission range SA2. Furthermore, the correction ratio for the second dimming range PA2 shows that the brightness increases from the center to the periphery of the dimming area PA.

[0086] Figure 10 shows a portion of the brightness adjustment data. The brightness adjustment data in Figure 10 shows the relationship between the position of the dimming sub-pixel Sp and the correction ratio in the cross-section of the dimming panel 30 along the AA line shown in Figure 7. The horizontal axis represents the X coordinate of the dimming area PA, and the vertical axis represents the correction ratio (%).

[0087] The luminance adjustment data is a curve that approximates the shape of the luminance distribution curve of the emission area SA shown in Figure 8 to a symmetrical shape with a straight line parallel to the horizontal axis as the axis of symmetry. Specifically, the correction ratio for the first dimming range PA1 is constant at 20%. The correction ratio changes continuously from the first dimming range PA1 to the second dimming range PA2. The correction ratio at the inner periphery of the second dimming range PA2 exceeds 20%, and the correction ratio increases from the center to the periphery of the dimming area PA, with the correction ratio at the outer periphery of the second dimming range PA2 being 80%.

[0088] Brightness adjustment data is determined individually for each display device 1. Specifically, the brightness of the emission area SA is measured for each display device 1 during manufacturing, and the brightness adjustment data is determined in accordance with the measured emission area SA and stored in the storage unit 11a. In other words, the brightness adjustment data is determined for each display device 1 in accordance with the individual differences of the light source device 40. Alternatively, the brightness adjustment data may be determined in accordance with the brightness of the emission area SA measured in advance by experiments or other means before the manufacturing of the display device 1 and stored in the storage unit 11a. In this case, the brightness adjustment data is determined regardless of the individual differences of the light source device 40, and the same brightness adjustment data is stored in the storage unit 11a of each of the multiple display devices 1.

[0089] The acquisition unit 11b acquires image signals corresponding to multiple pixels G. The image signals have gradation data indicating the gradation of the multiple pixels G. There are multiple gradation data sets corresponding to the first sub-display pixel Sd1, the second sub-display pixel Sd2, and the third sub-display pixel Sd3 that constitute the pixels G.

[0090] The grayscale data includes first grayscale data corresponding to the first sub-pixel Sd1, second grayscale data corresponding to the second sub-pixel Sd2, and third grayscale data corresponding to the third sub-pixel Sd3. When the first, second, and third grayscale data are not distinguished, they may simply be referred to as "grayscale data." The grayscale data possesses so-called gamma characteristics.

[0091] The first correction unit 11c linearizes each of the multiple grayscale data acquired by the acquisition unit 11b. Specifically, the first correction unit 11c corrects grayscale data having gamma characteristics to grayscale data having linearity by applying a linearization coefficient to the grayscale values ​​of the grayscale data. This linearization coefficient is stored in advance in the storage unit 11a.

[0092] The light transmittance calculation unit 11d calculates the light transmittance (%) of the dimming panel 30. First, in the linearized grayscale data, the light transmittance calculation unit 11d identifies the highest grayscale value (hereinafter referred to as the highest grayscale value) among the grayscale values ​​of the three grayscale data corresponding to one pixel G for each of the multiple pixels G.

[0093] Furthermore, the light transmittance calculation unit 11d calculates a tone ratio for each of the multiple pixels G, which is the ratio of the highest tone value to the maximum tone value. For example, if the tone data is 8-bit data and the tone values ​​are represented by values ​​from 0 to 255, the maximum tone value is 255, and the tone ratio is the value obtained by dividing the highest tone value by 255.

[0094] Furthermore, the light transmittance calculation unit 11d multiplies each of the multiple pixels G by the correction ratio of the range of the dimming area PA corresponding to the pixel G (i.e., one of the first dimming area PA1 and the second dimming area PA2) and the gradation ratio. The light transmittance calculation unit 11d takes the result of this multiplication as the light transmittance of the range of the dimming area PA that overlaps with the pixel G in a plan view. In other words, the light transmittance of the dimming panel 30 is calculated for each pixel G and the range of the dimming area PA that overlaps with it in a plan view, i.e., for each set of dimming sub-pixels CSp (three dimming sub-pixels Sp).

[0095] The dimming sub-gradation data generation unit 11e generates dimming sub-gradation data for each of the multiple dimming sub-pixels Sp, indicating the gradation value of the dimming sub-pixel Sp. Specifically, for each of the multiple dimming sub-pixels Sp, the dimming sub-gradation data generation unit 11e generates data as dimming sub-gradation data that shows the value obtained by multiplying the transmittance in the dimming region PA where the dimming sub-pixel Sp is located by the highest gradation value of the pixel G corresponding to that dimming sub-pixel Sp. Therefore, the gradation values ​​of the three dimming sub-pixels Sp that constitute a set of dimming sub-pixels CSp corresponding to one pixel G are equal to each other.

[0096] The display sub-grayscale data generation unit 11f generates display sub-grayscale data indicating the gradation value of each of the multiple display sub-pixels Sd. Specifically, the display sub-grayscale data generation unit 11f generates first display sub-grayscale data corresponding to the first display sub-pixel Sd1, second display sub-grayscale data corresponding to the second display sub-pixel Sd2, and third display sub-grayscale data corresponding to the third display sub-pixel Sd3.

[0097] More specifically, the display sub-grayscale data generation unit 11f generates first display sub-grayscale data for each of the multiple first display sub-pixels Sd1, which is data that represents the value obtained by multiplying the grayscale value of the first grayscale data of the pixel G corresponding to the first display sub-pixel Sd1 by the reciprocal of the grayscale ratio of that pixel G.

[0098] Similarly, the display sub-grayscale data generation unit 11f generates second display sub-grayscale data for each of the multiple second display sub-pixels Sd2, which represents the value obtained by multiplying the grayscale value of the second grayscale data of the pixel G corresponding to the second display sub-pixel Sd2 by the reciprocal of the grayscale ratio of that pixel G. Furthermore, the display sub-grayscale data generation unit 11f generates third display sub-grayscale data for each of the multiple third display sub-pixels Sd3, which represents the value obtained by multiplying the grayscale value of the third grayscale data of the pixel G corresponding to the third display sub-pixel Sd3 by the reciprocal of the grayscale ratio of that pixel G. Note that when explaining common matters without distinguishing between the first display sub-grayscale data, second display sub-grayscale data, and third display sub-grayscale data, they may simply be referred to as "display sub-grayscale data."

[0099] The second correction unit 11g performs gamma correction on the dimming sub-gradation data generated by the dimming sub-gradation data generation unit 11e and the display sub-gradation data generated by the display sub-gradation data generation unit 11f. Specifically, the second correction unit 11g applies a gamma value to the gradation values ​​of the dimming sub-gradation data and the display sub-gradation data, thereby correcting the linear dimming sub-gradation data and display sub-gradation data to dimming sub-gradation data and display sub-gradation data with gamma characteristics. This gamma value is pre-stored in the storage unit 11a.

[0100] The output unit 11h generates multiple display sub-pixel signals containing gamma-corrected display sub-gradation data and outputs them to the first signal output circuit 12. The output unit 11h also generates multiple dimming sub-pixel signals containing gamma-corrected dimming sub-gradation data and outputs them to the second signal output circuit 14.

[0101] Next, the operation of the drive circuit 10, the display panel 20, and the dimming panel 30 will be explained using Figures 11 and 12. Figure 11 is a flowchart of the actions performed by the drive circuit 10. Figure 12 is a diagram showing the values ​​that the drive circuit 10 calculates when generating dimming sub-gradation data and display sub-gradation data.

[0102] When the light source device 40 is controlled as described above, the luminance distribution of the emission area SA is as shown in Figures 7 and 8, and the case in which the gradation values ​​of the gradation data in multiple pixels G are equal to each other and white is displayed across the entire display area DA is explained.

[0103] Furthermore, the gradation data, display sub-gradation data, and dimming sub-gradation data are 8-bit data, and the process by which the gradation values ​​of the display sub-pixel Sd and dimming sub-pixel Sp corresponding to pixels G located at points α, β, and γ shown in Figures 7 and 8 are calculated will be explained in detail.

[0104] As shown in Figures 7 and 8, the pixel G corresponding to point α corresponds to the first pixel located in the first emission range SA1, and the pixels G corresponding to points β and γ correspond to the second pixel located in the second emission range SA2. Furthermore, as shown in Figure 10, the dimming sub-pixel Sp corresponding to point α is located in the first dimming range PA1, and the dimming sub-pixels Sp located at points β and γ are located in the second dimming range PA2.

[0105] As shown in Figures 8 and 12, the luminance (A) of the emission region SA at points α, β, and γ are 100%, 50%, and 25%, respectively. Also, as shown in Figures 10 and 12, the correction ratio (B) at points α, β, and γ are 20%, 40%, and 80%, respectively.

[0106] As shown in Figure 11, the acquisition unit 11b acquires the image signal in step S1. When white is displayed across the entire display area DA, the gradation data of all pixels G shows the maximum gradation value of 255, and the gradation values ​​of the three gradation data of pixels G located at points α, β, and γ are all 255. Subsequently, the first correction unit 11c linearizes the gradation data in step S2.

[0107] Furthermore, in step S3, the light transmittance calculation unit 11d determines the highest tone value. As described above, the tone values ​​of the three tone data of pixels G located at points α, β, and γ are 255, so the highest tone value (C) of pixels G located at points α, β, and γ is "255" (Figure 12).

[0108] Next, in step S4, the light transmittance calculation unit 11d calculates the gradation ratio (= maximum gradation value (C) / 255). The gradation ratio (D) of the pixels G located at points α, β, and γ is "1" (Figure 12).

[0109] Furthermore, in step S5, the light transmittance calculation unit 11d calculates the light transmittance (= correction ratio (B) × gradation ratio (D)). The light transmittances of the dimming sub-pixels Sp corresponding to points α, β, and γ are "20%", "40%", and "80%" respectively (Figure 12).

[0110] Next, in step S6, the dimming sub-gradation data generation unit 11e generates dimming sub-gradation data including the gradation value of the dimming sub-pixel Sp (= maximum gradation value (C) × light transmittance (E)). The gradation values ​​(F) of the dimming sub-pixel Sp corresponding to points α, β, and γ are "25", "51", and "204".

[0111] Furthermore, in step S7, the display sub-gradation data generation unit 11f generates display sub-gradation data including the gradation value of the display sub-pixel Sd (= maximum gradation value (C) × (1 / gradation ratio (D)). The gradation values ​​(G) of the display sub-pixel Sd corresponding to points α, β, and γ are "255", "255", and "255".

[0112] Next, in step S8, the second correction unit 11g performs gamma correction on the dimming sub-gradation data and the display sub-gradation data. In step S9, the output unit 11h outputs the display sub-pixel signal, which includes the display sub-gradation data, to the first signal output circuit 12, and outputs the dimming sub-pixel signal, which includes the dimming sub-gradation data, to the second signal output circuit 14.

[0113] As described above, the second signal output circuit 14 transmits multiple dimming sub-pixel signals to the corresponding dimming sub-pixels Sp, and as the multiple dimming sub-pixels Sp operate, the light transmittance in the dimming region PA is adjusted for each set of dimming sub-pixels CSp.

[0114] Specifically, the light transmittance of one pair of dimming sub-pixels CSp corresponding to pixel G located at point α is adjusted to 20%, the light transmittance of one pair of dimming sub-pixels CSp corresponding to pixel G located at point β is adjusted to 40%, and the light transmittance of one pair of dimming sub-pixels CSp corresponding to pixel G located at point γ is adjusted to 80%. In addition, the light transmittance of the first dimming range PA1 of the dimming region PA, which includes pixel G located at point α, is constant at 20%, and the light transmittance changes continuously from the first dimming range PA1 to the second dimming range PA2. The light transmittance of the second dimming range PA2, which includes pixel G located at points β and γ, increases from the center to the periphery of the dimming region PA, exceeding 20% ​​and increasing to 80%.

[0115] Furthermore, as described above, the first signal output circuit 12 transmits multiple display sub-pixel signals to the corresponding display sub-pixels Sd. As the multiple display sub-pixels Sd operate, an image (an image that is entirely white) is displayed in the display area DA. At this time, the brightness of the image displayed in the display area DA (i.e., the luminance of the display area DA) is determined by the luminance of the output area SA, the transmittance of the dimming panel 30, and the transmittance of the display panel 20. Specifically, when expressing the luminance of the display area DA in terms of grayscale values, it can be calculated by multiplying the luminance (A) of the output area SA shown in Figure 12, the transmittance (E), and the grayscale values ​​(G) of the display sub-pixels Sd that constitute the pixels G.

[0116] The brightness (H = brightness of the output area SA (A) × transmittance (E) × gradation value of the sub-display pixel Sd (G)) of the display area DA at pixel G located at point α is "51". The brightness (H) of the display area DA at pixel G located at point β is "51". The brightness (H) of the display area DA at pixel G located at point γ is "51". Thus, when the gradation values ​​of the gradation data of multiple pixels G are equal to each other, the brightness of the display area DA at pixel G located at points α, β, and γ will be equal to each other.

[0117] Figure 13 shows a portion of the brightness of the display area DA when the grayscale values ​​of the grayscale data in multiple pixels G are equal to each other. The brightness of the display area DA in Figure 13 shows the relationship between the position of the display subpixel Sd and the brightness in the cross-section of the display panel 20 along the AA line shown in Figure 7. The horizontal axis represents the X coordinate of the display area DA, and the vertical axis represents the brightness of the display area DA as a percentage, with the highest brightness in the display area DA defined as 100%.

[0118] As shown in Figure 13, the brightness of the display area DA is constant throughout the entire X direction. Also, similar to Figure 13, in a plan view, the brightness is almost constant within the range of the display area DA corresponding to the first dimming range PA1 and the second dimming range PA2 of the dimming area PA, respectively (i.e., the entire display area DA).

[0119] As described above, by correcting the gradation values ​​of the dimming panel 30 and the display panel 20 using brightness adjustment data, the brightness of the display area DA can be made uniform even when the brightness of the output area SA is not uniform. In other words, when the gradation values ​​of multiple pixels G are the same, the brightness of the display area DA that displays the image can be made uniform.

[0120] When brightness adjustment data is not used, the brightness of the display area DA is calculated by multiplying the brightness of the output area SA (A) by the gradation value of the display sub-gradation data (255 if white is displayed across the entire display area DA), assuming that the overall light transmittance of the dimming area PA is constant at, for example, 100%.

[0121] Specifically, as shown in Figure 12, when the gradation values ​​of the gradation data in multiple pixels G are equal to each other, and white is displayed across the entire display area DA, the luminance (X (= luminance of the output area SA (A) × 255)) of the display area DA at pixels G located at points α, β, and γ respectively is "255", "127", and "64". Thus, when luminance adjustment data is not used, the luminance of the display area DA corresponds to the luminance of the output area SA, and when white is displayed across the entire display area DA, the luminance at the periphery of the display area DA is lower than the luminance at the center of the display area DA.

[0122] <Modified form of the first embodiment> Next, we will describe the differences between the display device 1 according to a modified example of the first embodiment and the first embodiment described above.

[0123] In this modified example, the brightness adjustment data is set such that the brightness at the periphery of the display area DA is slightly lower than the brightness at the center of the display area DA.

[0124] Specifically, at the outer periphery of the second dimming range PA2, the correction ratio of this modified example is set lower than the correction ratio (80%) of the first embodiment shown in Figure 10, for example, 65%. As a result, at points α, β, and γ, the correction ratio (B) is set to, for example, 20%, 35%, and 65%. As a result, when the gradation values ​​of the gradation data in multiple pixels G are equal to each other and white is displayed across the entire display area DA, the luminance (H) of the display area DA at points α, β, and γ will be "51", "45", and "41".

[0125] Figure 14 shows a portion of the brightness of the display area DA in a modified example of the first embodiment, where the gradation values ​​of the gradation data in multiple pixels G are equal to each other. The brightness of the display area DA in Figure 14, similar to Figure 13, shows the relationship between the position of the display sub-pixel Sd and the brightness in a cross-section of the display panel 20 along the AA line shown in Figure 7.

[0126] As shown in Figure 14, the brightness at both ends of the display area DA in the X direction is lower than the brightness at the center. Similarly, in a plan view of the display area DA, the brightness at the periphery is lower than the brightness at the center. Even in this case, the brightness of the display area DA is more uniform compared to when brightness adjustment data is not used.

[0127] <Second Embodiment> Next, the display device 1 according to the second embodiment of this disclosure will be described, primarily focusing on the differences from the first embodiment described above. In this second embodiment, the luminance distribution and luminance adjustment data of the emission region SA differ from those of the first embodiment described above.

[0128] In this second embodiment, the second emission range SA2 is located in the center of the emission region SA in a plan view. The brightness of the emission region SA in the second emission range SA2 is approximately constant.

[0129] The first emission range SA1 is located on the peripheral side of the emission region SA in a plan view. Specifically, the first emission range SA1 is adjacent to the second emission range SA2 and lies between the periphery of the second emission range SA2 and the periphery of the emission region SA. Furthermore, the luminance changes continuously from the second emission range SA2 to the first emission range SA1, and in the first emission range SA1, the luminance increases from the center to the periphery of the emission region SA before decreasing.

[0130] Figure 15 shows the luminance distribution of the emission region SA in a cross-section of the light source device 40 along the AA line shown in Figure 7, in the second embodiment. As shown in Figure 15, in the second emission range SA2, the luminance is almost constant at a lower luminance (e.g., 40%) than that of the first emission range SA1.

[0131] Furthermore, the brightness at the inner periphery of the first emission range SA1 exceeds, for example, 40%, increases toward the outer periphery of the first emission range SA1 to, for example, 100%, and then decreases toward the periphery of the emission region SA.

[0132] The light source control circuit 16 controls the light intensity of the light-emitting elements 44 so that the brightness distribution of the emission region SA is as described above. Specifically, the light source control circuit 16 reduces the light intensity of the light-emitting elements 44 that overlap with the second emission region SA2 in a plan view to the light intensity of the light-emitting elements 44 that overlap with the first emission region SA1 in a plan view. As a result, the brightness of the light-emitting elements 44 corresponding to the second emission region SA2 becomes weaker than the brightness of the light-emitting elements 44 corresponding to the first emission region SA1.

[0133] Furthermore, the light source control circuit 16 increases the light intensity of the multiple light-emitting elements 44 that overlap with the first emission range SA1 in a plan view, from the inner periphery to the outer periphery of the first emission range SA1, and then decreases it.

[0134] The brightness adjustment data of this second embodiment is defined such that the brightness of the display area DA becomes uniform when the gradation values ​​of the gradation data in multiple pixels G are equal, corresponding to the brightness distribution of the output area SA of the second embodiment described above. In the brightness adjustment data, the correction ratio of the second dimming range PA2 corresponding to the second output range SA2 is constant and is greater than the correction ratio corresponding to the first dimming range PA1 corresponding to the first output range SA1. Furthermore, the correction ratio changes continuously from the second dimming range PA2 to the first dimming range PA1, and the correction ratio of the first dimming range PA1 increases after the brightness decreases from the center to the periphery of the dimming area PA.

[0135] Figure 16 shows a portion of the brightness adjustment data for the second embodiment. The brightness adjustment data in Figure 16 shows the relationship between the position of the dimming sub-pixel Sp (in other words, the X coordinate of the dimming area PA) and the correction ratio in the cross-section of the dimming panel 30 along the AA line shown in Figure 7.

[0136] The luminance adjustment data is a curve that approximates the shape of the luminance distribution curve of the emission area SA shown in Figure 15 to a symmetrical shape with a straight line parallel to the horizontal axis as the axis of symmetry. Specifically, the correction ratio of the second dimming range PA2 is constant at, for example, 80%. The correction ratio at the inner periphery of the first dimming range PA1 is, for example, less than 80%, and the correction ratio decreases from the center to the periphery of the dimming area PA, for example to 25%, and then increases towards the periphery of the emission area SA.

[0137] While preferred embodiments of this disclosure have been described above, this disclosure is not limited to such embodiments. The content disclosed in the embodiments is merely an example, and various modifications are possible without departing from the spirit of this disclosure. Any modifications made without departing from the spirit of this disclosure will naturally fall within the technical scope of this disclosure.

[0138] For example, in each of the above embodiments, the arrangement of the multiple light-emitting elements 44 may be changed to achieve the brightness distribution of the emission region SA shown in Figures 7, 8, and 15. Specifically, the higher the brightness of the emission region SA, the greater the number of light-emitting elements 44 arranged per unit area. In other words, the number of light-emitting elements 44 arranged per unit area in the area of ​​the main surface 41a that overlaps with the first emission region SA1 in a plan view is greater than the number of light-emitting elements 44 arranged per unit area in the area of ​​the main surface 41a that overlaps with the second dimming region PA2 in a plan view.

[0139] Furthermore, while the highest gradation value is determined from three gradation data points corresponding to a single pixel G, it may also be determined from gradation data points corresponding to a set of pixels composed of multiple adjacent pixels G. In this case, the light transmittance of the dimming panel 30 is calculated for each set of pixels and the dimming area PA that overlaps with it in a planar view, i.e., for each set of dimming sub-pixels CSp.

[0140] Needless to say, the luminance of the emission area SA and the correction ratio of the luminance adjustment data are not limited to the above values, nor are the first emission range SA1, second emission range SA2, first dimming range PA1, and second dimming range PA2 limited to the above ranges. For example, in the luminance distribution of the emission area SA shown in Figure 15, the second emission range SA2 may be located closer to the periphery of the emission area SA than the first emission range SA1.

[0141] Furthermore, the display panel 20 may be a vertical electric field type liquid crystal display in which a common electrode CE is arranged on the second substrate 23 so as to face multiple sub-pixel electrodes PE. Alternatively, the display panel 20 may be a reflective type liquid crystal display.

[0142] Alternatively, the light source device 40 may be an edge-type backlight unit in which the light-emitting elements 44 are arranged on the inner surface of the frame 42.

[0143] Furthermore, the brightness of the emitted light in the second emission range SA2 may be greater than or equal to the brightness of the emitted light in the first emission range SA1.

[0144] Furthermore, any other effects and advantages brought about by the embodiments described herein that are obvious from this specification or that can be appropriately conceived by those skilled in the art are naturally provided by this disclosure. [Explanation of Symbols]

[0145] 1 Display device 10 Drive circuit 20 Display Panel 30 Dimming Panels 40 Light source device 41 Electrical circuit board 41a Main surface of electrical circuit board 44 light-emitting elements DA display area G pixels PA dimming area PA1 First dimming range PA2 Second dimming range SA emission area SA1 First firing range SA2 Second firing range Sd sub-pixels Sp light-adjusting sub-pixel

Claims

1. A display panel having a display area with multiple pixels, A light source device that emits light toward the display panel from an emission area that overlaps with the display area in a plan view, A dimming panel is positioned between the display panel and the light source device and adjusts the brightness of the emitted light emitted from the emission area in a dimming area that overlaps with the display area in a plan view. The system includes a drive circuit for driving the dimming panel, The aforementioned light source device is An electrical circuit board having a main surface superimposed on the emission region in a plan view, in which a plurality of light-emitting elements are arranged in a matrix, The system comprises a frame positioned laterally from the aforementioned electrical circuit board, The dimming panel has a plurality of dimming sub-pixels arranged in a matrix in the dimming area, and the brightness of the emitted light can be adjusted for each of the plurality of dimming sub-pixels. The ejection region has a first ejection range and a second ejection range. One of the first emission range and the second emission range is located in the center of the emission region in a plan view. The other emission range of the first emission range and the second emission range surrounds the first emission range in a plan view. In a plurality of pixels, if the grayscale value of the first pixel corresponding to the first emission range is equal to the grayscale value of the second pixel among the plurality of pixels corresponding to the second emission range, The drive circuit makes the light transmittance of the second dimming range corresponding to the second pixel higher than the light transmittance of the first dimming range corresponding to the first pixel in the dimming region. Display device.

2. The first emission range is located in the center of the emission region in a plan view, The second emission range surrounds the first emission range in a plan view. The display device according to claim 1.

3. The second emission range is located in the center of the emission region in a plan view, The first emission range surrounds the second emission range in a plan view. The display device according to claim 1.

4. The display device according to any one of claims 1 to 3, wherein the brightness of the emitted light in the second emission range is weaker than the brightness of the emitted light in the first emission range.

5. The brightness of each of the plurality of light-emitting elements is equal to that of the others. The display device according to any one of claims 1 to 3.

6. In a plurality of light-emitting elements, the brightness of the light-emitting element corresponding to the second emission range is weaker than the brightness of the light-emitting element corresponding to the first emission range. The display device according to any one of claims 1 to 3.

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