control device

Abstract

A display device includes a backlight having a light emitting region including light emitting elements, and a control device. The light emitting elements include a first light emitting component that emits first light, a second light emitting component that emits second light having a peak wavelength shorter than the first light, and a third light emitting component that emits third light having a peak wavelength shorter than the second light. The first, second, and third light emitting components are fluorescent components that receive invisible light to emit the first, second, and third light as fluorescent light, respectively. The control device generates pixel data for a subpixel that displays the first light using a first time constant, generates pixel data for a subpixel that displays the second light using a second time constant different from the first time constant, and generates pixel data for a subpixel that displays the third light using a third time constant different from the first time constant.

Description

Technical Field

[0001] The following disclosure relates to a control device for controlling a display device having multiple light-emitting components that emit different colors. Background Technology

[0002] In recent years, various studies have been conducted on display devices that use multiple light-emitting components (light-emitting materials) that emit different colors to achieve color display. For example, Patent Document 1 discloses a technique for addressing the degradation of display quality caused by the differences in the afterglow characteristics of the various light-emitting materials. Specifically, in the technique of Patent Document 1, an analog afterglow signal is added to the image signal corresponding to the light-emitting material with a short afterglow time.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-141204 Summary of the Invention

[0006] The technical problem to be solved by the present invention

[0007] However, as will be described later, there is room for improvement in the specific methods used to improve the display quality of a display device. One aspect of this disclosure aims to improve the display quality of a display device having multiple light-emitting components that emit different colors, using a method different from the conventional approach.

[0008] Technical solutions for solving technical problems

[0009] To address the aforementioned problems, one aspect of this disclosure relates to a control device that controls a display device, characterized in that the display device comprises: a display panel having a display area with a plurality of display pixels arranged thereon, the display panel displaying an image based on an image signal; a backlight having at least one light-emitting area illuminating the plurality of display pixels based on the image signal; the at least one light-emitting area having at least one light-emitting element as a light source, each of the plurality of display pixels having: (i) a first display sub-pixel displaying a first color; (ii) a second display sub-pixel displaying a second color different from the first color; and (iii) a third display sub-pixel displaying a third color different from both the first and second colors, each of the at least one light-emitting element having: an excitation light source emitting invisible light as an excitation light; a first light-emitting component receiving the invisible light and emitting a first light as fluorescence, the first light being light of the first color; a second light-emitting component receiving the invisible light and emitting a second light as fluorescence, the second light being light of the second color and having a peak wavelength shorter than the first light; and a third light-emitting component receiving the invisible light and emitting a third light as fluorescence, the third light being light of the first color; The light of the third color has a peak wavelength shorter than that of the second light. Each of the at least one light-emitting element emits a mixture of the first light, the second light, and the third light as a mixed light towards the plurality of display pixels. The control device includes: a backlight brightness calculation unit that generates backlight brightness data based on the image signal; and a display pixel data generation unit that generates display pixel data based on the backlight brightness data and the image signal. The display pixel data includes: (i) first display sub-pixel data corresponding to the first display sub-pixel; (ii) second display sub-pixel data corresponding to the second display sub-pixel; and (iii) third display sub-pixel data corresponding to the third display sub-pixel. The display pixel data generation unit (i) generates the first display sub-pixel data using a first time constant, (ii) generates the second display sub-pixel data using a second time constant different from the first time constant, and (iii) generates the third display sub-pixel data using a third time constant different from the first time constant.

[0010] Beneficial effects

[0011] According to one aspect of this disclosure, the display quality of a display device having multiple light-emitting components that emit different colors can be improved by a method different from the past. Attached Figure Description

[0012] Figure 1 This is a block diagram showing the configuration of the main components of the display device according to Embodiment 1.

[0013] Figure 2 This is a diagram showing a schematic configuration of the light-emitting element in Embodiment 1.

[0014] Figure 3 This is a diagram showing the correspondence between the light-emitting area and the light-emitting element of BL in Embodiment 1.

[0015] Figure 4 It is a diagram used to illustrate the brightness distribution of a light-emitting element.

[0016] Figure 5 This is a diagram showing an example of the configuration of the BL luminance distribution color filter calculation unit in Embodiment 1.

[0017] Figure 6 This is a diagram showing an example of f(R) and f(G, B).

[0018] Figure 7 This is a diagram illustrating the relationship between BL brightness, panel transmittance, and displayed image brightness in an ideal display device.

[0019] Figure 8 This is a graph illustrating the relationship between BL brightness, panel transmittance, and displayed image brightness in Comparative Example 1.

[0020] Figure 9 This is a graph illustrating the relationship between BL brightness, panel transmittance, and displayed image brightness, referred to as Comparative Example 2.

[0021] Figure 10 This is a diagram illustrating the relationship between BL brightness, panel transmittance, and displayed image brightness in display device 1.

[0022] Figure 11 This is a block diagram showing the configuration of the main parts of a display device according to a modified embodiment of 1.

[0023] Figure 12 This is a diagram illustrating an example of the configuration of the BL brightness distribution color filter calculation unit in the display device of Embodiment 2.

[0024] Figure 13 This is a diagram showing an example of a calibration table in Embodiment 2.

[0025] Figure 14 This is a diagram illustrating the relationship between BL brightness, panel transmittance, and displayed image brightness in the reference example.

[0026] Figure 15 This is a diagram illustrating the relationship between BL brightness, panel transmittance, and displayed image brightness in display device 2.

[0027] Figure 16This is a block diagram showing the configuration of the main components of the display device according to Embodiment 3. Detailed Implementation

[0028] [Implementation Method 1]

[0029] The display device 1 according to Embodiment 1 will be described below. For ease of explanation, components that have the same function as those described in the first embodiment will be labeled with the same reference numerals in subsequent embodiments, and their descriptions will not be repeated. In addition, for the sake of simplicity, descriptions of matters that are the same as those in the prior art will be appropriately omitted.

[0030] It is important to note that the components and values ​​described in this specification are for illustrative purposes only unless otherwise specified. Therefore, the positional relationships of the components are not limited to the examples in the figures unless otherwise specified. Furthermore, it should be noted that each figure roughly illustrates the shape, structure, and positional relationships of each component and is not necessarily drawn to scale. In this specification, regarding the two numbers A and B… Unless otherwise specified, such a record refers to "A or above and B or below".

[0031] The following abbreviations are used in this specification:

[0032] • Backlight: "BL"

[0033] Local Dimming (LD):

[0034] • Color Filter: "CF"

[0035] Electroluminescence (EL):

[0036] Photo-Luminescence: "PL".

[0037] Furthermore, the "afterglow characteristics of luminescent materials" as described in this specification collectively refers to both the "delay characteristic of the intensity of light emitted from the luminescent material" and the "delay characteristic of the intensity of light emitted from the luminescent material". Therefore, in this specification, "afterglow time" collectively refers to both the "delay time of the intensity of light" and the "delay time of the intensity of light".

[0038] (Overview of display device 1)

[0039] Figure 1This is a block diagram showing the configuration of the main parts of the display device 1. The display device 1 includes a control unit 10 (control device), an image signal acquisition unit 20, and a display unit 30. The display device 1 displays images based on image signals according to a specified video standard. As an example of a specified video standard, the HDR (High Dynamic Range) standard can be cited. The display device 1 can be a portable terminal device or a fixed device.

[0040] The control unit 10 uniformly controls all parts of the display device 1. As described below, in one aspect of this disclosure, the control unit processes the image signal provided by the image signal acquisition unit 20. Therefore, the control device in one aspect of this disclosure can also be called an image processing device. The control unit 10 includes a BL luminance calculation unit 11, a BL luminance filter calculation unit 12, and a display pixel data generation unit 13. The display pixel data generation unit 13 includes a BL luminance distribution calculation unit 131, a BL luminance distribution filter calculation unit 132, and a transmittance determination unit 133. Examples of the operation of each part of the control unit 10 will be described later.

[0041] The image signal acquisition unit 20 acquires an image signal. As an example, the image signal acquisition unit 20 acquires the image signal by decoding a broadcast signal received by the display device 1. As another example, the image signal acquisition unit 20 may also acquire the image signal from an external device (not shown) communicatively connected to the display device 1. An example of such an external device is a BD (Blu-lay Disc) player. The image signal acquisition unit 20 provides the acquired image signal to the control unit 10. Specifically, as shown in FIG1, the image signal acquisition unit 20 supplies the image signal to the BL brightness calculation unit 11 and the transmittance determination unit 133.

[0042] The display unit 30 is, for example, a liquid crystal display (LCD). The display unit 30 includes a BL31 and a display panel 35. The display panel 35 is an example of a display panel according to one aspect of this disclosure. The display panel 35 has a plurality of display pixels 350 (e.g., liquid crystal pixels) whose light transmittance (hereinafter referred to as transmittance) can be controlled. Specifically, the display panel 35 has I1 × J1 display pixels 350. I1 represents the number of display pixels in each row, and J1 represents the number of display pixels in each column. Both I1 and J1 are integers greater than or equal to 2. Thus, the display pixels 350 are arranged in a two-dimensional matrix in the display area (the area displaying the image) of the display panel 35. The transmittance of the display pixels 350 is controlled according to the image signal.

[0043] Display pixel 350 has a plurality of display subpixels for color display of an image. In Embodiment 1, display pixel 350 has: (i) a first display subpixel displaying a first color, (ii) a second display subpixel displaying a second color, and (iii) a third display subpixel displaying a third color. The first color to the third color are different colors. In Embodiment 1, the case where the first color is red, the second color is green, and the third color is blue is illustrated. However, of course, the first color to the third color are not limited to this example.

[0044] In Embodiment 1, the display pixel 350 includes: (i) a red display subpixel (displaying red) serving as a first display subpixel, (ii) a green display subpixel (displaying green) serving as a second display subpixel, and (iii) a blue display subpixel (displaying blue) serving as a third display subpixel. In the following description, the red display subpixel is abbreviated as RSUB, the green display subpixel as GSUB, and the blue display subpixel as BSUB.

[0045] BL31 illuminates display pixel 350. The BL31 in Embodiment 1 is an example of a BL with LD (Light Emitting Difference) function. Therefore, BL31 has multiple light-emitting areas 305 whose brightness can be independently controlled (see below). Figure 3 ).exist Figure 1 In this example, BL31 is positioned on the back of the display panel 35. However, BL31 only needs to illuminate the display pixels 350. Therefore, the configuration of BL31 is not limited to... Figure 1 Examples.

[0046] BL31 has I2 × J2 light-emitting regions 305. I2 represents the number of light-emitting regions in each row, and J2 represents the number of light-emitting regions in each column. In the example of Embodiment 1, both I2 and J2 are integers greater than 2. Thus, BL31 in Embodiment 1 is composed of multiple light-emitting regions 305 divided in two dimensions. Therefore, BL31 in Embodiment 1 can also be called a two-dimensional dimming type BL.

[0047] However, BL31 can also have multiple luminescent regions 305 that are divided in one dimension. That is, either I2 or J2 can be 1. For example, BL31 can also be divided into 1×J2 luminescent regions 305. Alternatively, BL31 can also be divided into I2×1 luminescent regions 305.

[0048] Thus, the light emission control method of this disclosure can also be applied to the light emission region 305, which is divided into one dimension. When either I2 or J2 is 1, BL31 can also be referred to as a one-dimensional dimming type BL. The one-dimensional dimming type BL and the two-dimensional dimming type BL can also be collectively referred to as LD type BL. In addition, it should be noted that, as described in Embodiment 3 below, the light emission control method of this disclosure can also be applied to non-LD type BLs.

[0049] In BL31, each of the plurality of light-emitting regions 305 contains at least one light-emitting element 310 as a light source. In Embodiment 1, for the sake of simplicity, the case where one light-emitting region 305 contains one light-emitting element 310 is illustrated. Therefore, BL31 in Embodiment 1 has 12 × J2 light-emitting elements 310. The brightness of the light-emitting region 305 (more specifically, the brightness of the light-emitting element 310) is controlled according to the image signal.

[0050] There is no particular limitation on the type of light-emitting element 310. In Embodiment 1, a white LED (Light Emitting Diode) is shown as an example. More specifically, in Embodiment 1, a QLED (Quantum Dot LED) is shown as an example.

[0051] (Example of the structure of light-emitting element 310)

[0052] Figure 2 This is a diagram showing a schematic configuration of the light-emitting element 310. In this specification, from... Figure 2 The direction from the second electrode 322 to the first electrode 327 is referred to as upward. Furthermore, the opposite direction is referred to as downward. In the following description, the vertical direction will also be referred to as the z-direction. The z-direction can also represent the normal direction of the display surface of the display panel 35. Figure 2 In the example, the positive direction of the z-direction is upward.

[0053] like Figure 2 As shown, the light-emitting element 310 includes an excitation light source 320, a phosphor component 330 (wavelength conversion component), and a CF component 340. The excitation light source 320, moving upwards, includes a substrate 321, a first electrode 322, a hole injection layer 323, a hole transport layer 324, an ultraviolet QD (Qunatum Dot) layer 325, an electron transport layer 326, and a second electrode 327. Figure 2 In the example, the first electrode 322 and the second electrode 327 are the anode and cathode, respectively. The second electrode 327 is transparent in a way that allows ultraviolet light (hereinafter referred to as LUV) emitted from the ultraviolet QD layer 325 to be transmitted.

[0054] The ultraviolet QD layer 325 is a light-emitting layer (ultraviolet QD phosphor particle layer) containing ultraviolet QD phosphor particles (not shown). In the excitation source 320, as a voltage is applied between the first electrode 322 and the second electrode 327, holes are supplied from the first electrode 322 to the QD layer 325, and electrons (free electrons) are supplied from the second electrode 327 to the QD layer 325. The ultraviolet QD phosphor particles emit LUV as holes and electrons recombine. Thus, the QD layer 325 emits light through an EL (more specifically, an injection EL). As an example, the wavelength range of the LUV is 350 nm to 380 nm, and the peak wavelength of the LUV is 365 nm. Thus, the excitation light of one embodiment of the present disclosure is invisible light (e.g., ultraviolet light).

[0055] In the excitation source 320, the QD layer 325 (and its corresponding layers) is in Figure 2 The horizontal direction is divided into three regions (SEC1 to SEC3). More specifically, in the excitation light source 320, multiple switching elements are provided in each of SEC1 to SEC3 such that a separate voltage can be applied to the QD layer 325. Examples of such switching elements include thin-film transistors (TFTs). Therefore, the light-emitting state of the QD layer 325 can be controlled individually in each of SEC1 to SEC3. From the following... The emitted LUVs are respectively called exist Figure 2 In the example, SEC1 is set as RSUB, SEC2 is set as GSUB, and SEC3 is set as a portion of the area corresponding to BSUB.

[0056] The phosphor component 330 is positioned above the excitation light source 320 at a location corresponding to SEC1 to SEC3. The phosphor component 330 converts the wavelength of LUV (LUV1 to LUV3) emitted from the QD layer 325. More specifically, the phosphor component 330 receives LUV1 to LUV3 as excitation light and emits fluorescence of a different color than ultraviolet light. In Embodiment 1, the phosphor component 330 emits red (first color), green (second color), and blue (third color) fluorescence.

[0057] In this specification, the light of the first color to the light of the third color are referred to as the first light to the third light, respectively. Furthermore, the second light has a shorter peak wavelength than the first light. Furthermore, the third light has a shorter peak wavelength than the second light. Then, in this specification, the components emitting the first light to the third light are referred to as the first light-emitting component to the third light-emitting component, respectively. Furthermore, the components emitting... The phosphor components that fluoresce are respectively called

[0058] In Embodiment 1, the red phosphor component 331R, green phosphor component 331G, and blue phosphor component 331B described below are examples of a first light-emitting component, a second light-emitting component, and a third light-emitting component (more specifically, a first phosphor component, a second phosphor component, and a third phosphor component), respectively. Therefore, Figure 2 LR, LG, and LB are examples of the first, second, and third beams, respectively.

[0059] The phosphor component 330 includes a red phosphor component 331R (red wavelength conversion component), a green phosphor component 331G (green wavelength conversion component), and a blue phosphor component 331B (blue wavelength conversion component). The red phosphor component 331R is positioned corresponding to SEC1. The red phosphor component 331R contains red QD phosphor particles (not shown). These red QD phosphor particles receive LUV1 as excitation light, thereby emitting red light (LR) as fluorescence. Thus, the red phosphor component 331R converts LUV1 into fluorescence, i.e., LR, with a peak wavelength longer than LUV1. As an example, the wavelength range of LR is 620 nm to 640 nm, and the peak wavelength of LR is 630 nm. Figure 2 In the example, in SEC1, the red CF341R is emitted to the display panel 35 via LR.

[0060] Similarly, a green phosphor component 331G is positioned corresponding to SEC2. The green phosphor component 331G contains green QD phosphor particles (not shown). These green QD phosphor particles receive LUV2 as excitation light, thereby emitting green light (LG) as fluorescence. Thus, the green phosphor component 331G converts LUV2 into fluorescence, i.e., LG, which has a longer peak wavelength than LUV3. Furthermore, as can be clearly seen from the color correspondence, the peak wavelength of LG is shorter than that of LR. For example, the wavelength range of LG is 522 nm to 542 nm, and the peak wavelength of LG is 532 nm. Figure 2 In the example, in SEC2, the LG emits light through the green CF341G as described below to the display panel 35.

[0061] Similarly, a blue phosphor component 331B is positioned corresponding to SEC3. The blue phosphor component 331B contains blue QD phosphor particles (not shown). These blue QD phosphor particles receive LUV3 as excitation light, thereby emitting blue light (LB) as fluorescence. Thus, the blue phosphor component 331B converts LUV3 into fluorescence, i.e., LB, with a peak wavelength longer than that of LUV3. Furthermore, as can be clearly seen from the color correspondence, the peak wavelength of LB is shorter than that of LG. For example, the wavelength range of LB is 457 nm to 477 nm, while the peak wavelength of LG is 467 nm. Figure 2 In the example, in SEC3, the LG emits light through the blue CF341B as described below to the display panel 35.

[0062] As described above, the red phosphor component 331R, the green phosphor component 331G, and the blue phosphor component 331B, unlike the ultraviolet QD layer 325, emit light via PL. The light intensities of LR, LG, and LB can be varied by adjusting the light intensities of LUV1 to LUV3, which serve as excitation light.

[0063] As described above, the light-emitting element 310 can supply the display panel 35 with light mixed with LR, LG, and LB (mixed light). Therefore, by appropriately adjusting the light amounts of LR, LG, and LB, a desired hue can be expressed using the mixed light. In Embodiment 1, the case where the light-emitting element 310 emits white light (more precisely, near-white light) as the mixed light is illustrated. This is also the case in Embodiment 3, which will be described later.

[0064] Furthermore, in the light-emitting element 310, by using the red phosphor component 331R, the green phosphor component 331G, and the blue phosphor component 331B, which respectively contain QD phosphor elements, as the red light source, the green light source, and the blue light source, respectively, the half-width and fluorescence peak wavelengths of the red, green, and blue light can be precisely controlled. That is, the monochromaticity of the red light (LR) in the RSUB, the monochromaticity of the green light (LG) in the GSUB, and the monochromaticity of the blue light (LB) in the BSUB can be improved respectively. Therefore, based on the light-emitting element 310, a display device 1 with excellent display quality (especially color reproduction) can be realized.

[0065] However, phosphor component 330 may not be able to convert all LUV received in SEC1 to SEC3 into light of different wavelengths. Specifically, red phosphor component 331R may not be able to convert all of LUV1 into LR. That is, a portion of LUV1 is not absorbed by red phosphor component 331R and passes through it. Similarly, a portion of LUV2 is not absorbed by green phosphor component 331G and passes through it. Furthermore, a portion of LUV3 is not absorbed by blue phosphor component 331B and passes through it. Hereinafter, LUV1 that passes through red phosphor component 331R will be referred to as first residual ultraviolet light. In addition, LUV2 that passes through green phosphor component 331G will be referred to as second residual ultraviolet light. In addition, LUV3 that passes through blue phosphor component 331B will be referred to as third residual ultraviolet light.

[0066] Therefore, in Figure 2 In the example of the light-emitting element 310, in order to reduce the influence of the first residual ultraviolet light, the second residual ultraviolet light, and the third residual ultraviolet light, the CF component 340 is disposed above the phosphor component 330. More specifically, the CF component 340 is configured to cover the phosphor component 330 when viewed from the display surface of the display panel 35.

[0067] The CF component 340 includes a red CF341R, a green CF341G, and a blue CF341B. To reduce the impact of the first residual ultraviolet light in the RSUB, the red CF341R is positioned at the location corresponding to SEC1 (the location corresponding to the red phosphor component 331R). Similarly, to reduce the impact of the second residual ultraviolet light in the GSUB, the green CF341G is positioned at the location corresponding to SEC2 (the location corresponding to the green phosphor component 331G). Likewise, to reduce the impact of the third residual ultraviolet light in the BSUB, the blue CF341B is positioned at the location corresponding to SEC3 (the location corresponding to the blue phosphor component 331B).

[0068] The red CF341R exhibits high transmittance in the red band but relatively low transmittance in other bands. The green CF341G exhibits high transmittance in the green band but relatively low transmittance in other bands. The blue CF341BG exhibits high transmittance in the blue band but relatively low transmittance in other bands.

[0069] By providing the CF component 340, (i) the first residual ultraviolet light heading towards the display surface can be blocked using the red CF341R, (ii) the second residual ultraviolet light heading towards the display surface can be blocked using the green CF341G, and (iii) the third residual ultraviolet light heading towards the display surface can be blocked using the blue CF341B. Therefore, the monochromaticity of LR, LG, and LB in the display unit 30 can be further improved. Therefore, the display quality of the display device 1 can be further improved. However, depending on the required display quality of the display device 1, the CF component 340 may be omitted. This also applies to the CF component 440 of Embodiment 3 described later.

[0070] Of course, the configuration of the light-emitting element 310 is not limited to... Figure 2 For example, the light-emitting element 310 can be implemented using any known configuration. For instance, it can also be implemented using... Figure 2 The example demonstrates a simpler configuration for implementing the light-emitting element 310. As an example, the light-emitting element 310 could also be a light-emitting element in which an ultraviolet LED (ultraviolet excitation source), a red phosphor component (red wavelength conversion component), a green phosphor component (green wavelength conversion component), and a blue phosphor component (blue wavelength conversion component) are encapsulated within a single package.

[0071] (Example of the brightness distribution of the light-emitting element 310)

[0072] Figure 3 This is a diagram showing the correspondence between the light-emitting region 305 and the light-emitting element 310 in BL31. As described above, in Figure 3 In the example, a light-emitting region 305 corresponds to a light-emitting element within that region 305. Figure 3 In the example, the subscript i represents the row position in BL31, and the subscript j represents the column position. i is an integer satisfying 1 ≤ i ≤ I². j is an integer satisfying 1 ≤ j ≤ J².

[0073] The row and column directions in BL31 correspond to the affected row (vertical) and column (horizontal) directions, respectively. Therefore, the row and column directions in BL31 also correspond to the row and column directions in display panel 35, respectively. Figure 3 In the example, the light-emitting region 305 located in the i-th row and j-th column of BL31 is labeled REG(i,j). Furthermore, the light-emitting element 310 of REG(i,j) is labeled LS(i,j). Figure 3 In the diagram, white circles represent light-emitting elements 310 that are in the lit state (light-emitting state), and black circles represent light-emitting elements 310 that are in the off state (non-light-emitting state).

[0074] As described above, in the display device 1, the brightness of the light-emitting element 310 is controlled according to the image signal. Furthermore, in the following description, "brightness of the light-emitting element 310" can be appropriately replaced with "brightness of the light-emitting area 305". As an example, consider the case where the image represented by the image signal is a white window pattern with a black background. In this case, the control unit 10 illuminates the light-emitting element 310 located at the position corresponding to the white window pattern.

[0075] exist Figure 3 In this example, a 3×3 rectangular area centered at REG(3,5) corresponds to the white window pattern. In this case, the control unit 10 illuminates the following nine light-emitting elements:

[0076] ·LS(2,4), LS(2,5), LS(2,6):

[0077] ·LS(3,4), LS(3,5), LS(3,6):

[0078] ·LS(4,4), LS(4,5), LS(4,6).

[0079] On the other hand, the control unit 10 turns off the light-emitting elements 310 other than the nine light-emitting elements.

[0080] Figure 4 This is a diagram used to illustrate the brightness distribution of the light-emitting element 310. Figure 4 The reference numeral 4100 indicates an example of the two-dimensional brightness distribution of a light-emitting element 310 in a lit state. As indicated by reference numeral 4100, the brightness of the light-emitting element 310 peaks at the center of the element and decreases as it moves away from the center. In the display device 1, this brightness distribution is modeled using a pre-defined PSF (Point Spread Function). Figure 4 The reference numeral 4200 indicates a graph representing the brightness distribution of reference numeral 4100 using a one-dimensional plot. As an example, the horizontal axis "position" of this graph represents the position of BL31 in the row or column direction. In this case, the graph shows the brightness distribution of a light-emitting element 310 in the row or column direction of BL31.

[0081] Figure 4 The reference numeral 4300 is a graph representing the one-dimensional brightness distribution of multiple (e.g., three) light-emitting elements 310 in the lit state. The graph of reference numeral 4300 is paired with the graph of reference numeral 4200. As an example, in the following description, let LS(2,4), LS(2,5), and LS(2,6) be the three light-emitting elements 310 mentioned above.

[0082] In reference numeral 4300, DisA, DisB, and DisC represent the brightness distributions of LS(2,4), LS(2,5), and LS(2,6), respectively. As shown in reference numeral 4300, DisB is obtained by shifting DisA to the right by only one portion of the distance of the light-emitting element 310. Similarly, DisC is obtained by shifting DisB to the right by only one portion of the distance of the light-emitting element 310. In other words, DisC is obtained by shifting DisA to the right by only two portions of the distance of the light-emitting element 310.

[0083] In display device 1, settings are pre-set to display respectively The PSF. Furthermore, in the display device 1, the brightness distribution of the three light-emitting elements 310 (DisT in the curve of reference numeral 4300) is calculated by performing an operation that adds DisA, DisB and DisC together.

[0084] In display device 1, the luminance distribution (BL luminance distribution) of light illuminating each of the plurality of display pixels 350 from BL31 is calculated based on the PSF using a known calculation model. This calculation model is constructed to reproduce the actual luminance distribution of BL31. As described below, in display device 1, the display panel 35 is controlled based on the BL luminance distribution in addition to the image signal.

[0085] (BL Brightness Calculation Section 11)

[0086] Refer again Figure 1 The operation of each part of the control unit 10 will be explained. The BL brightness calculation unit 11 generates BL brightness data based on the image signal acquired from the image signal acquisition unit 20. The BL brightness data refers to data representing the brightness of BL31 during each frame of the image.

[0087] As described above, BL31 in Embodiment 1 is an LD-type BL. Therefore, the BL luminance calculation unit 11 generates BL luminance data for the LD-type BL based on the image signal. In a specific example, the BL luminance calculation unit 11 generates BL luminance data representing the luminance of LS(1, 1) to LS(12, J2) during each frame period. The BL luminance calculation unit 11 provides the generated BL luminance data to the BL luminance filter calculation unit 12.

[0088] (BL Brightness Filter Calculation Unit 12)

[0089] The BL luminance filter calculation unit 12 uses a known color filter (e.g., a digital color filter) to correct the BL luminance data. More specifically, the BL luminance filter calculation unit 12 uses a color filter to smooth the BL luminance data. Hereinafter, the BL luminance data corrected by the BL luminance filter calculation unit 12 will be referred to as the corrected BL luminance data. The BL luminance filter calculation unit 12 provides the corrected BL luminance data to BL31 and the BL luminance distribution calculation unit 131.

[0090] The color filter in the BL luminance filter calculation unit 12 is not particularly limited as long as it can smooth the BL luminance data. For example, the color filter only needs to be able to delay the time change of the BL luminance data according to an arbitrarily set time constant. Therefore, for example, a known low-pass color filter can be used as a color filter for smoothing the BL luminance data.

[0091] Specific examples of the aforementioned color filters include IIR (Infinite Impulse Response) color filters and FIR (Finite IR) color filters. Furthermore, to reduce the computational load in the color filter, an IIR color filter is preferred. These descriptions of the color filters in the BL luminance color filter calculation unit 12 also apply to the BL luminance distribution color filter calculation unit 132, which will be described later.

[0092] Generally, the response speed of the display panel 35 (panel response speed) is lower than that of the BL 31 (BL response speed). Therefore, when the BL 31 is driven according to the BL brightness data, flicker may occur in the display unit 30 due to the difference between the BL response speed and the panel response speed. In particular, the likelihood of flickering is high when scene changes occur in the image. This degrades the display quality of the image displayed on the display unit 30, and is therefore undesirable for the display device 1.

[0093] Therefore, in Embodiment 1, the control unit 10 drives BL31 according to the BL brightness data after calibration. As a specific example, the control unit 10 drives LS(1,1) to LS(I2,J2) according to the calibrated BL brightness data. By driving BL31 in this way, the difference between the BL response speed and the panel response speed can be reduced. Therefore, the display quality of the image displayed on the display unit 30 can be improved.

[0094] (BL luminance distribution calculation part 131)

[0095] Next, each part of the display pixel data generation unit 13 will be described. The BL brightness distribution calculation unit 131 calculates the BL brightness distribution based on (i) the corrected BL brightness data obtained from the BL brightness filter calculation unit 12 and (ii) the preset PSF.

[0096] In display device 1, the PSF is set for the color of the mixed light emitted from the light-emitting element 310 (for convenience, referred to as the mixed color). As described above, the mixed color in the example of Embodiment 1 is white. Therefore, in Embodiment 1, the display pixel data generation unit 13 calculates the BL luminance distribution of white light. In this specification, the BL luminance distribution of white light is denoted as f(W). f(W) is an example of the mixed light BL luminance distribution according to one aspect of this disclosure. The mixed light BL luminance distribution means the distribution of the luminance of the mixed light illuminating each of the plurality of display pixels 350 from BL 31. The display pixel data generation unit 13 provides the f(W) calculated during each frame to the BL luminance distribution color filter calculation unit 132.

[0097] (BL luminance distribution color filter calculation unit 132)

[0098] Figure 5 This diagram illustrates an example configuration of the BL luminance distribution color filter calculation unit 132. The BL luminance distribution color filter calculation unit 132 uses a known color filter to smooth f(W), thereby calculating the first light BL luminance distribution, the second light BL luminance distribution, and the third light BL luminance distribution. The first light BL luminance distribution refers to the luminance distribution of the first light illuminating the plurality of display pixels 350 from BL31. The same definition also applies to the second light BL luminance distribution and the third light BL luminance distribution. The BL luminance distribution color filter calculation unit 132 calculates... Provided to the transmittance determination unit 133.

[0099] exist Figure 5 In the example, the BL luminance distribution color filter operation unit 132 smooths f(W) using an IIR color filter. Figure 5 In the example, the BL luminance distribution color filter operation unit 132 uses a...

[0100] H(z) = a0 / (1-b1×z) -1 (1)

[0101] The transfer function H(z) is used to smooth f(W). Furthermore, a0 = 1 / (1+b1). Additionally, 0 <b1<1。

[0102] Figure 5In the example, the BL luminance distribution filter operation unit 132 includes amplifiers 1321a and 1321b, a frame delay circuit 1322, and an adder 1323. Those skilled in the art will understand that these functional units are interconnected to implement H(z) of equation (1). The amplifiers 1321a and 1321b have gains of a0 and b1, respectively. These gains are variable. The frame delay circuit 1322 outputs data held during the previous frame during the next frame.

[0103] Here, the time constant of the color filter having the transfer function of equation (1) is denoted as τ. As will be apparent to those skilled in the art, between τ and b1,

[0104] b1=exp(-t / τ)…(2)

[0105] This relationship holds true. t is the frame period of the image. t is the reciprocal of the frame rate f of the image. In Embodiment 1, f = 120Hz. Therefore, in Embodiment 1, t = 8.34ms. As defined by Equation (2), the desired τ can be obtained in the BL luminance distribution color filter calculation unit 132 by appropriately selecting the value of b1.

[0106] For example, consider the case where τ is set to 10ms in the BL luminance distribution color filter calculation unit 132. In this case, setting b1 = exp(-0.834) = 0.434 is sufficient. Therefore, setting a0 = 1 / (1.434) = 0.697 is also sufficient. In this way, by adjusting the gains of amplifiers 1321a and 1321b respectively, τ can be set to the desired value.

[0107] The BL luminance distribution filter operation unit 132 can be configured to adjust the gains of amplifiers 1321a and 1321b according to equation (2) so that they correspond to the desired τ. In other words, the BL luminance distribution filter operation unit 132 can also set τ according to the frame rate. Thus, the BL luminance distribution filter operation unit 132 can also be configured to set at least one of the first time constant, the second time constant, and the third time constant described later according to the frame rate.

[0108] It is known that in most cases (especially when using luminescent materials with excellent monochromaticity), the afterglow time of longer wavelength light is longer than that of shorter wavelength light. Therefore, for example, in most cases, the afterglow time of the first light (e.g., LR) is longer than that of the second light (e.g., LG) and the third light (e.g., LB). As an example, in the luminescent element 310 of Embodiment 1, the afterglow time of LR is approximately 100 to 1000 times longer than that of LG and LB. More specifically, the afterglow time of LR is approximately tens of milliseconds.

[0109] In view of this, it can be said that in order to improve the display quality of the display device 1, it is preferable to drive the display panel 35 in a manner that eliminates the influence of residual light from the LR. Therefore, in Embodiment 1, the BL luminance distribution color filter calculation unit 132 smooths f(W) by H(z) and thereby calculates the red light BL luminance distribution f(R). f(R) is an example of the first light BL luminance distribution.

[0110] Figure 6 An example of f(R) calculated by the BL luminance distribution color filter calculation unit 132 is shown. Figure 6 The horizontal axis in the graph represents time. Figure 5 In the example, f(W) is a step function that takes a High value (corresponding to the lighting of the light-emitting element 310) during the time interval t1 to t2. Figure 5 As shown, f(R) is calculated as a function representing the first-order hysteresis response after delaying f(W) by a time constant τ.

[0111] In this specification, the time constant used to calculate the brightness distribution of the first light BL is referred to as the first time constant. In particular, the time constant used to calculate f(R) is referred to as the red light time constant (τR). The red light time constant is an example of the first time constant. As described above, in Embodiment 1, τR is set to, for example, 10 ms. The value of τR, taking into account the afterglow time of LR, can be appropriately set by the designer of the display device 1.

[0112] However, as explained above, in Embodiment 1, the afterglow times of LG and LB are sufficiently short compared to the afterglow time of LR. Therefore, it is considered that even if the afterglow times of LG and LB are approximately considered to be 0, it will not have any effect. Therefore, as an example, the BL luminance distribution color filter calculation unit 132 can set the green light BL luminance distribution f(G) and the blue light BL luminance distribution f(B) to be equal to f(W).

[0113] As from Figure 5 as well as Figure 6 As understood, in Embodiment 1, the BL luminance distribution color filter calculation unit 132 makes

[0114] f(G)=f(B)=f(G,B)=f(W)…(3)

[0115] Let f(G) and f(B) be defined. f(G) and f(B) are examples of the BL luminance distributions of the second and third light sources, respectively. f(G,B) is the BL luminance distribution shared by both green and blue light. f(G,B) is referred to as the green / blue light BL luminance distribution.

[0116] As described above, the second and third light BL brightness distributions can also be set to a common (identical) distribution. In this specification, this common brightness distribution is referred to as the second and third light BL brightness distributions. The aforementioned f(G, B) is an example of the second / third light BL brightness distribution.

[0117] In this specification, the time constant used to calculate the luminance distribution of the second light BL is referred to as the second time constant. Specifically, the time constant used to calculate f(G) is referred to as the green light time constant (τG). The green light time constant is an example of the second time constant. Similarly, the time constant used to calculate the luminance distribution of the third light BL is referred to as the third time constant. Specifically, the time constant used to calculate f(B) is referred to as the blue light time constant (τB).

[0118] When the second and third light BL brightness distributions are set to the same value (e.g., second / third light BL brightness distribution), the second time constant is equal to the third time constant. However, the second and third time constants can also be set to different values. For example, the second time constant can be set to a value greater than the third time constant.

[0119] As can be understood from the above description, in most cases, the first time constant is preferably set to a value larger than the second and third time constants. In view of this, in Embodiment 1, f(G) and f(B) of the above equation (3) are set. In this case, as from... Figure 6 As is understandable, we set τG = τB = τ(G, B) = 0 ms (time constant zero). τ(G, B) is the time constant shared by both green and blue light. τ(G, B) is called the green / blue light time constant.

[0120] As described above, in Embodiment 1, the BL luminance distribution color filter calculation unit 132 does not delay f(W), but directly outputs f(W) as f(G, B) (see also...). Figure 5In other words, the BL luminance distribution color filter operation unit 132 generates f(G, B) by applying a color filter (identical color filter) with a transfer function C(z) = 1 to f(W). The identity color filter can also be a color filter with a time constant of 0 and a gain of 1.

[0121] Furthermore, in this specification, "BL luminance distribution color filter calculation unit 132 performs constant color filtering on f(W) to generate f(G, B)" also includes "BL luminance distribution color filter calculation unit 132 does not delay f(W), but directly outputs f(W) as f(G, B)". Therefore, it is important to note that in the BL luminance distribution color filter calculation unit 132, the constant color filter may not be installed as an actual hardware or software element (see also the above). Figure 5 ).

[0122] (Transmittance Determination Section 133)

[0123] The transmittance determination unit 133 (i) obtains an image signal from the image signal input unit, and (ii) obtains an image signal from the BL luminance distribution color filter calculation unit 132. exist Figure 1 In the example, the transmittance determination unit 133 acquires the image signal and f(R) and f(G, B). Based on the image signal and the brightness distributions of the first light BL to the third light BL, the transmittance determination unit 133 generates display pixel data (e.g., liquid crystal pixel data). The display pixel data refers to data representing the transmittance of each of the multiple display pixels 350.

[0124] In Embodiment 1, the transmittance determination unit 133 generates display pixel data that includes first display subpixel data (e.g., red display subpixel data), second display subpixel data (e.g., green display subpixel data), and third display subpixel data (e.g., blue display subpixel data). The first display subpixel data refers to data representing the transmittance of each of the plurality of first display subpixel data. The same definition also applies to the second and third display subpixel data.

[0125] The transmittance determination unit 133 obtains the brightness values ​​of the first to third colors in the image from the image signal. In Embodiment 1, the transmittance determination unit 133 obtains the brightness value d(R) of red, the brightness value d(G) of green, and the brightness value d(B) of blue in the image.

[0126] Furthermore, the transmittance determination unit 133 determines the transmittance g(R) of the red display sub-pixel based on d(R) and f(R). In Embodiment 1, the transmittance determination unit 133 calculates g(R) by dividing d(R) by f(R). That is, the transmittance determination unit 133 uses d(R) and f(R) as the base values.

[0127] g(R)=d(R) / f(R)…(4)

[0128] Calculate g(R).

[0129] Similarly, the transmittance determination unit 133 calculates the transmittance g(G) of the green display sub-pixel based on (i)d(G) and f(G), and calculates the transmittance g(B) of the blue display sub-pixel based on (ii)d(B) and f(B). As described above, in Embodiment 1, f(G) = f(B) = f(G, B).

[0130] Therefore, the transmittance determining part is

[0131] g(G)=d(G) / f(G)=d(G) / f(G) / f(G,B)…(5)

[0132] g(B)=d(B) / f(B)=d(B) / f(G,B)…(6)

[0133] Calculate g(G) and g(B) respectively.

[0134] The transmittance determination unit 133 generates (i) data representing g(R) as red display subpixel data, (ii) data representing g(G) as green display subpixel data, and (iii) data representing g(B) as blue display subpixel data.

[0135] The control unit 10 drives the display panel 35 based on the display pixel data. Specifically, the control unit 10 drives each of the plurality of display pixels 350 based on the display pixel data. More specifically, the control unit 10 drives the RSUB, GSUB, and BSUB of each of the plurality of display pixels 350 based on the red display subpixel data, green display subpixel data, and blue display subpixel data.

[0136] As described above, the display pixel data generation unit 13 generates display pixel data based on BL luminance data and image signals (in the example of Embodiment 1, based on corrected BL luminance data and image signals). Therefore, in the display device 1, the display panel 35 can be driven in coordination with the driving of BL 31. Furthermore, the display pixel data generation unit 13 generates red display sub-pixel data, green display sub-pixel data, and blue display sub-pixel data using different time constants such as τR = 10 ms and τ(G, B) = 0 ms. Therefore, in the display device 1, the display panel 35 can be driven to eliminate the influence of differences in the afterglow time of each color light. For example, in the display device 1, the display panel 35 can be driven to eliminate the influence of LR afterglow.

[0137] (Effect)

[0138] Figure 7 This diagram illustrates the relationship between BL brightness, panel transmittance (the transmittance of the display panel), and image brightness (the brightness of the image displayed on the display panel) in an ideal display device. In this ideal display device, the afterglow time of red, green, and blue light is all 0. Figure 7 The liquid crystal transmittance in the image can also be replaced with display pixel data.

[0139] Figure 7 The graph G11 illustrates an example of the temporal variation of BL brightness in an ideal display device. In the example of G11, the BL brightness takes a High value from time t1 to t2. This temporal variation of BL brightness occurs as an example during a scene where the displayed image is bright, from t1 to t2. On the other hand, as... Figure 7 As shown in Figure G12, the panel transmittance is constant regardless of time. In the following... Figure 8 and Figure 9 The panel transmittance is also shown in G12 in the description.

[0140] Figure 7 Graph G13 illustrates an example of the temporal variation of the display image brightness in an ideal display device. The display image brightness is defined by the product of the BL brightness and the panel transmittance. Therefore, as shown in G13, in an ideal display device (i.e., where the afterglow times of red, green, and blue light are all equal), the temporal variation of the display image brightness is consistent with the temporal variation of the BL brightness.

[0141] Figure 8 This is a graph illustrating the relationship between BL brightness, panel transmittance, and displayed image brightness in an existing practical display device (referred to as Comparative Example 1 for convenience). As described above, in the practical display device, the afterglow time of red light is sufficiently long compared to the afterglow time of green light and blue light (collectively referred to as "green-blue light" in the following description).

[0142] Figure 8 Graph G21 illustrates an example of the time-varying brightness of BL in Comparative Example 1. In G21, solid lines represent green-blue light, and dashed lines represent red light. This is consistent with the subsequent graphs. Figure 8 As shown, in t1, the brightness of green-blue light (the brightness of green-blue light) rapidly increases towards the High value. On the other hand, the brightness of red light (the brightness of red light) increases slowly compared to the brightness of green-blue light. Figure 8In the example, at time t1a, the red light brightness reaches the High value (refer to part S210 of G21). Thus, in Comparative Example 1, t1 to t1a is the period during which green and blue light have a greater influence than red light.

[0143] Subsequently, in t2, the brightness of green and blue light rapidly decreased to a Low value. On the other hand, the brightness of red light decreased slowly compared to the brightness of green and blue light. Figure 8 In the example, at time t2a, the red light brightness reaches a Low value (refer to part S211 of G21). Thus, in Comparative Example 1, t2 to t2a is the period during which red light has a greater influence than green and cyan light.

[0144] Figure 8 Graph G23 shows an example of the time-varying brightness of the displayed image in Comparative Example 1. The time-varying brightness of each color of light in the displayed image is determined by the product of the brightness of each color of BL light and the panel transmittance. Therefore, in t1 to t1a, even in the displayed image, the brightness of green and blue light is greater than that of red light. As a result, in t1 to t1a, corresponding to S210 above, the displayed image produces a green-blue tint (refer to part S230 of G23). Similarly, in t2 to t2a, the displayed image produces a red tint (refer to part S231 of G23), corresponding to S211 above.

[0145] Figure 9 This diagram illustrates the relationship between BL brightness, panel transmittance, and displayed image brightness in the display device of Patent Document 1 (referred to as Comparative Example 2 for convenience). The display device of Patent Document 1 is an example of a technology used to solve the problem points in Comparative Example 1. Specifically, in order to reduce the color rendering of the displayed image, the display device of Patent Document 1 adds an analog persistence signal to the image signal. In other words, the display device of Patent Document 1 generates an analog persistence signal (analog persistence) in the BL to reduce the color rendering of the displayed image.

[0146] Figure 9 Graph G31 illustrates an example of the time-varying brightness of BL in Comparative Example 2. As shown in G31, in Comparative Example 2, from t1 to t1a, in order to completely eliminate the effect of the rise delay of red brightness, a simulated green-blue afterglow was added in a manner that reproduces the rise delay of simulated green-blue emission (see section S310 of G31). Furthermore, in Comparative Example 2, from t2 to t2m, in order to reduce (partially eliminate) the effect of the fall delay of red brightness, a simulated green-blue afterglow was added in a manner that reproduces the fall delay of simulated green-blue emission (see section S311 of G31). t2m <t2a。

[0147] Figure 9Graph G33 shows an example of the time-varying brightness of the displayed image in Comparative Example 2. In Comparative Example 2, during t1 to t1a, corresponding to S310 above, the green-blue tint in the displayed image was eliminated (see part S330 of G33). Furthermore, in Comparative Example 2, during t2 to t2a, the red tint in the displayed image was reduced, corresponding to S311 above (see part S331 of G33). Thus, in Comparative Example 2, the tint in the displayed image was reduced. Additionally, in Comparative Example 2, whether the tint of each color in the displayed image can be completely eliminated depends on the maximum value of the simulated afterglow brightness that can be generated.

[0148] However, in Comparative Example 2, by adding an analog persistence signal to the image signal, a different display image was presented to the user of the display device. Thus, the method of Comparative Example 2, which involves "adding an analog persistence signal to the image signal in order to reduce coloration in the display image," is potentially problematic from the viewpoint of image reproducibility.

[0149] In view of this, the inventors of this application (hereinafter referred to as the "inventors") came up with the idea of ​​"preferably reducing the coloration in the displayed image by a method different from Comparative Example 2". The display device 1 was recreated by the inventors based on this idea.

[0150] Figure 10 This is a diagram illustrating the relationship between the BL brightness, panel transmittance, and displayed image brightness of display device 1. Figure 10 In the example, the time variation of BL brightness is set to be the same as in Comparative Example 1. That is, in display device 1, unlike Comparative Example 2, no analog persistence signal is added to the image signal (in other words, the backlight does not produce analog persistence).

[0151] Figure 10 The graph G42 illustrates an example of the time-varying translucency of the liquid crystal in display device 1. As described above, display device 1 generates red display sub-pixel data, green display sub-pixel data, and blue display sub-pixel data based on the corrected BL brightness data and the image signal. As shown in G42, in Figure 10 In the example, the green and blue light transmittance (transmittance of green and blue light), i.e., g(G) and g(B), are set to constant values ​​independent of time. On the other hand, the red light transmittance (transmittance of red light), i.e., g(R), is set to correspond to the changes in S210 and S211 over time as described above.

[0152] Specifically, the red light transmittance in t1 to t1a is set to counteract the effect of the gradual increase in red light brightness shown in S210. Figure 10In the example, the red light transmittance rapidly increases to its maximum value at t1. After that, up to t1a, the red light transmittance decreases linearly (see part S420 of G42).

[0153] Similarly, the red light transmittance in t2 to t2a is set to counteract the gradual decrease in red light brightness shown in S211. Figure 10 In the example, the red light transmittance decreases rapidly to a minimum at t2. Afterward, up to t2a, the red light transmittance increases linearly (see section S421 of G42).

[0154] Figure 10 The graph G43 shows an example of the time-varying brightness of the displayed image in display device 1. In display device 1, from t1 to t1a, corresponding to S420 above, the green-blue tint in the displayed image is eliminated (see part S430 of G43). Furthermore, in Comparative Example 2, from t2 to t2a, the red tint in the displayed image is reduced, corresponding to S421 above. Thus, the tint in the displayed image is also reduced in display device 1.

[0155] Furthermore, in display device 1, whether the coloring of each color in the displayed image can be completely eliminated depends on the color display sub-pixels ( Figure 10 In the example, the minimum and maximum transmittance values ​​achievable in the red display sub-pixel are shown. For example, in S431, even the minimum red light transmittance in the red display sub-pixel cannot completely offset the effect of the maximum red light brightness.

[0156] As described above, in display device 1, the coloration in the displayed image is reduced by a method different from that of Comparative Example 2, which "generates display sub-pixel data for each color by considering the different afterglow times of each color of light." Thus, according to display device 1, the display quality of a display device having multiple light-emitting components that emit different colors can be improved by a method different from the conventional approach. Furthermore, as understood from G43 above, according to display device 1, compared to Comparative Example 2, a display image closer to the original image can be presented to the user. Therefore, from the viewpoint of image reproduction, display device 1 can be considered more suitable than Comparative Example 2.

[0157] [Variation Example]

[0158] Figure 11 This is a block diagram illustrating the configuration of key components of a display device 1V according to a modified embodiment of Embodiment 1. The display device 1V replaces the display pixel data generation unit 13 with a display pixel data generation unit 13V. Furthermore, the control unit of the display device 1V is referred to as the control unit 10V (control device).

[0159] The display pixel data generation unit 13V includes a second BL luminance filter calculation unit 134 and a BL luminance distribution calculation unit 135 to replace the BL luminance distribution calculation unit 131 and the BL luminance distribution filter calculation unit 132. The BL luminance distribution calculation unit 135 includes a first luminance distribution calculation unit 136A and a second luminance distribution calculation unit 136B.

[0160] The second BL luminance filter calculation unit 134 uses a filter to smooth the corrected BL luminance data obtained from the BL luminance filter calculation unit 12. In the second BL luminance filter calculation unit 134, similar to the BL luminance distribution filter calculation unit 132 in Embodiment 1, τR = 10ms and τ(G,B) = 0ms are set.

[0161] The second BL luminance filter calculation unit 134 smooths the corrected BL luminance data using τR, thereby generating red-light corrected BL luminance data. The second BL luminance filter calculation unit 134 provides this red-light corrected BL luminance data to the first luminance distribution calculation unit 136A. Then, the second BL luminance filter calculation unit 134 smooths the corrected BL luminance data using τ(G, B), thereby generating green-blue light corrected BL luminance data. The second BL luminance filter calculation unit 134 provides this green-blue light corrected BL luminance data to the second luminance distribution calculation unit 136B.

[0162] The first luminance distribution calculation unit 136A calculates f(R) based on the red light-corrected BL luminance data and PSF. The first luminance distribution calculation unit 136A provides the calculated f(R) to the transmittance determination unit 133. Similarly, the second luminance distribution calculation unit 136B calculates f(G, B) based on the green-blue light-corrected BL luminance data and PSF. The second luminance distribution calculation unit 136B provides the calculated f(G, B) to the transmittance determination unit 133. Subsequent processing is the same as in Embodiment 1.

[0163] In Implementation 1, f(W) is calculated based on the corrected BL luminance data, and then f(W) is smoothed to derive f(R) and f(G, B). However, as in Display Device 1V, smoothing can also be performed before calculating the luminance distribution to derive f(R) and f(G, B).

[0164] [Implementation Method 2]

[0165] Figure 12 This is a diagram showing an example of the configuration of the BL brightness distribution color filter calculation unit 132W of the display device 2 according to Embodiment 2. Figure 12 Is with Figure 5The images are paired. Furthermore, the control unit and the display pixel data generation unit of the display device 2 are respectively referred to as the control unit 10W (control device) and the display pixel data generation unit 13W. The BL brightness distribution color filter calculation unit 132W also includes a correction circuit 1324.

[0166] Unlike the BL luminance distribution filter calculation unit 132, the BL luminance distribution filter calculation unit 132W calculates f(G, B) by correcting f(W) using the correction circuit 1324. In the following description, the case where the current frame of the image is the nth frame is illustrated. n is any integer. Then, f(W) in the current frame is denoted as f(W)(n). In the following description, the value of f(W)(n) is also referred to as the BL value of the current frame. Conversely, the value of f(W)(n-1), i.e., the value of f(W) in the previous frame, is also referred to as the BL value of the previous frame. Furthermore, f(G, B) in the current frame is also denoted as f(G, B)(n). In this specification, unless otherwise explicitly stated, f(G, B) represents f(G, B)(n).

[0167] The correction circuit 1324 (i) obtains f(W)(n) from the BL luminance distribution calculation unit 131, and (ii) obtains f(W)(n-1) from the frame delay circuit 1322. Then, the correction circuit 1324 corrects f(W)(n) using a pre-set correction table TBL.

[0168] In embodiment 2, the correction circuit 1324 is as shown on the right side of the following equation (7).

[0169] f(G, B)(n)

[0170] =TBL{f(W)(n-1), f(W)(n)}+f(W)(n)…(7),

[0171] By correcting f(W)(n), f(G,B)(n) is calculated. Then, the correction circuit 1324 provides the calculated f(G,B) to the transmittance determination unit 133.

[0172] Figure 13 This is a diagram illustrating an example of TBL. In TBL, the BL values ​​of the previous frame and the current frame are discretized into 11 levels (levels 0 to 10). Figure 13 In the example, the higher the level value, the higher the BL value.

[0173] exist Figure 13 In the example, TBL is set such that the absolute value of TBL{f(W)(n-1), f(W)(n)} is nonzero when the BL value of the current frame deviates significantly from the BL value of the previous frame. Figure 13In the example, when the BL value of the current frame is 5 levels or more greater than the BL value of the previous frame, TBL{f(W)(n-1), f(W)(n)} takes a positive value (except when the BL value of the current frame is level 10). On the other hand, when the BL value of the current frame is 5 levels or more less than the BL value of the previous frame, TBL{f(W)(n-1), f(W)(n)} takes a negative value (except when the BL value of the current frame is level 0). Thus, the value of TBL{f(W)(n-1), f(W)(n)} is determined by the combination of f(W)(n-1) and f(W)(n).

[0174] As described above, the BL luminance distribution color filter calculation unit 132W can correct f(W)(n) based on the degree of deviation between f(W)(n) and f(W)(n-1), thereby calculating f(G, B). Furthermore, as can be clearly understood from the description of Embodiment 1, in Embodiment 2, f(G) and f(B) can also be calculated as separate BL luminance distributions. The BL luminance distribution color filter calculation unit 132W only needs to be able to calculate f(G) and f(B) by correcting f(W)(n).

[0175] (Effects of Implementation Method 2)

[0176] Figure 14 This is another example of the relationship between BL brightness, panel transmittance and displayed image brightness in display device 1. Figure 14 The example is a reference example of implementation method 2. Figure 14 Graph G51 shows an example of the time-varying brightness of BL in the reference example. Figure 14 In the example, at time t3, the brightness of the green and blue light rapidly decreases to a Low value. On the other hand, the brightness of the red light decreases slowly compared to the brightness of the green and blue light. Then, at time t3a, the brightness of the red light reaches a Low value (see part S510 of G51).

[0177] Figure 14 The graph G52 represents an example of the time-varying transmittance of the panel in the reference example. As described above, in the display device 1, the red light transmittance after t3 is set in a manner that counteracts the effect of the slow decrease in red light brightness shown in S510. Figure 14 In the example, the red light transmittance rapidly decreases to a minimum at t3. Afterward, up to t3a, the red light transmittance increases linearly (see section S520 of G52).

[0178] Figure 14The graph G53 illustrates an example of the time-varying brightness of the displayed image in the reference example. In display device 1, after t3, the shading of red in the displayed image is reduced, corresponding to S520 described above (see part S530 of G53). However, in Figure 14 In the example, it is also similar to the one mentioned above. Figure 10 Similarly, it is not possible to completely eliminate the red tinting in the displayed image.

[0179] Figure 15 This is a diagram illustrating the relationship between the BL brightness, panel transmittance, and displayed image brightness of display device 2. Figure 15 In the example, the way the brightness of BL changes over time is the same as in the reference example. Figure 15 The graph G62 shows an example of the time-varying transmittance of the panel of display device 2. In display device 2, the red light transmittance after t3 is set in a manner similar to that in the reference example to counteract the effect of the slow decrease in red light brightness shown in S510 (see part S620 of G62).

[0180] Furthermore, in the display device 2, f(G, B) is calculated according to the above formula (7). That is, f(G, B) can be determined based on the degree of divergence (e.g., amount of change) between f(W)(n-1) and f(W)(n). Specifically, by following the formula... Figure 13 The TBL calculation f(G, B) is determined in a way that counteracts the effect of the sharp numerical change between f(W)(n-1) and f(W)(n). Therefore, in display device 2, the green and blue light transmittance after t3 is further set to counteract the effect of the gradual decrease in red light brightness shown in S510. Figure 15 In the example, the green-blue light transmittance rapidly increases to its maximum value at t3. After that, until t3a, the green-blue light transmittance decreases linearly (see part S621 of G62).

[0181] Figure 15 The graph G63 illustrates an example of the time-varying brightness of the displayed image in the display device 2. In the display device 2, based on setting the red light transmittance as described in S620 above, the green and blue light transmittance is set as described in S621 above, thereby eliminating the red coloration in the displayed image (see part S630 of G63). As described above, by changing not only the red light transmittance but also the green and blue light transmittance, the effect of the slow decrease in red light brightness can be eliminated more effectively.

[0182] However, in display device 2, it is desirable to ensure that the green and blue light transmittance is set as in S621, resulting in a slightly different display image presented to the user. For example, depending on the display quality required by the display device, the designer of the display device can appropriately select either display device 1 or 2 (in other words, either the BL brightness distribution filter calculation unit 132 or 132W).

[0183] [Implementation Method 3]

[0184] Figure 16 This is a functional block diagram showing the configuration of key components of the display device 3 according to Embodiment 3. The display unit of the display device 3 is referred to as the display unit 30U. The display unit 30U includes a BL31U instead of BL31. The BL31U has a light-emitting area (hereinafter simply referred to as a single light-emitting area) whose brightness can be controlled. The single light-emitting area includes, for example, a light source (not shown). As an example, the single light-emitting area includes a light-emitting element 310. Unlike BL31, BL31U does not have an LD function. Therefore, BL31U can be referred to as a non-LD type BL. Alternatively, BL31U can be referred to as a 0-dimensional dimming type BL. Thus, in the BL involved in one aspect of this disclosure, I2 = 1 and J2 = 1.

[0185] In Embodiment 3, the BL luminance calculation unit 11 generates BL luminance data for non-LD type BLs based on the image signal. Specifically, the BL luminance calculation unit 11 generates BL luminance data representing the luminance of a light-emitting element 310 during each frame period, i.e., the luminance of LS(1,1). Subsequent processing is the same as in Embodiment 1. As described above, the luminance control method of this disclosure can also be applied to non-LD type BLs. According to Embodiment 3, the same effects as in Embodiment 1 can also be obtained.

[0186] As described above, the BL according to one aspect of this disclosure only needs to have at least one light-emitting area that illuminates a plurality of display pixels. Moreover, the at least one light-emitting area only needs to have at least one light-emitting element as a light source.

[0187] In the above embodiments, a display pixel 350 having a first display sub-pixel, a second display sub-pixel, and a third display sub-pixel is illustrated. However, in one aspect of this disclosure, the display pixel only needs to have a first display sub-pixel and a second display sub-pixel.

[0188] Therefore, the light-emitting element according to one aspect of this disclosure can have a first light-emitting component and a second light-emitting component. As an example, the light-emitting element (i) has an excitation light source that emits ultraviolet light as excitation light (e.g., the excitation light source 320 described above), (ii) has a phosphor component (e.g., a yellow phosphor component) that receives the excitation light and emits a first light (e.g., yellow light) as fluorescence as a first light-emitting component, and (iii) has a phosphor component (e.g., a blue phosphor component) that receives the excitation light and emits a second light (e.g., blue light) as fluorescence as a second light-emitting component. In this case, the light-emitting element can emit white light as mixed light.

[0189] Based on the above, the display pixel data generation unit of this disclosure can (i) generate first display sub-pixel data (e.g., blue display sub-pixel data) using a first time constant, and (ii) generate second display sub-pixel data (e.g., yellow display sub-pixel data) using a second time constant different from the first time constant.

[0190] In the embodiments described above, examples are shown using light-emitting elements that emit light in a QD layer EL as excitation sources. However, other light-emitting elements such as LEDs and organic EL light-emitting elements can also be used as excitation sources. Furthermore, in the embodiments described above, examples are shown using QD phosphor particles as phosphor components. However, other phosphor components can also be used.

[0191] [Example of software implementation]

[0192] The control modules (especially control units 10 to 10W) ​​of the display devices 1 to 4 can be implemented by logic circuits (hardware) formed on integrated circuits (IC chips) or by software.

[0193] In the latter case, display devices 1-4 include a computer that executes commands for software, i.e., programs, to perform various functions. This computer includes, for example, at least a processor (control device) and at least a computer-readable storage medium for storing the program. Furthermore, in the aforementioned computer, the processor reads the program from the storage medium and executes the program to achieve one aspect of the purpose of this disclosure. As the processor, a CPU (Central Processing Unit) can be used, for example. As the recording medium, in addition to "non-transitory tangible media," such as ROM (Read Only Memory), magnetic tape, disks, cards, semiconductor memories, programmable logic circuits, etc., can also be used. Furthermore, RAM (Random Access Memory) can be further included to expand the program. Additionally, the program can be supplied to the computer via any transmission medium capable of transmitting the program (communication network, broadcast wave, etc.). Furthermore, one aspect of this disclosure can also be implemented as a data signal embodied by electronic transmission and embedded in a carrier wave.

[0194] [Additional Notes]

[0195] This disclosure is not limited to the embodiments described above. Various modifications can be made within the scope of the claims. Embodiments obtained by appropriately combining the technical methods disclosed in different embodiments are also included in the technical scope of this disclosure. Furthermore, new technical features can be formed by combining the technical methods disclosed in each embodiment.

[0196] Explanation of reference numerals in the attached figures

[0197] 1.1V, 2.3 Display devices

[0198] 10V, 10W Control Unit (Control Device)

[0199] 11 BL Brightness Calculation Unit (Backlight Brightness Calculation Unit)

[0200] 12BL Luminance Filter Calculation Unit

[0201] 13, 13V, 13W Display Pixel Data Generation Unit

[0202] 30, 30U Display Section

[0203] 31, 31U BL (backlit)

[0204] 35 Display Panel

[0205] 131 and 135 BL luminance distribution calculation unit

[0206] 132, 132W BL luminance distribution color filter processing unit

[0207] 133 Transmittance Determining Unit

[0208] 136A First Luminance Distribution Calculation Unit

[0209] 136B Second Luminance Distribution Calculation Unit

[0210] 305 Emitting Area

[0211] 310 Light-emitting element

[0212] 320 Excitation source (an excitation source that emits invisible light as excitation light)

[0213] 325 UV QD layer

[0214] 330 Phosphor Components

[0215] 331R Red Phosphor Component (First Light-Emitting Component, First Phosphor Component)

[0216] 331G Green Phosphor Component (Second Light-Emitting Component, Second Phosphor Component)

[0217] 331B Blue phosphor component (third light-emitting component, third phosphor component)

[0218] 340 CF parts

[0219] 350 display pixels

[0220] f(W) White light BL brightness distribution (mixed light backlight brightness distribution)

[0221] f(R) Red light BL brightness distribution (first light backlight brightness distribution)

[0222] f(G, B) Green / blue light BL brightness distribution (second light backlight brightness distribution, third light backlight brightness distribution)

[0223] LR Red light (fluorescence, first light)

[0224] LG green light (fluorescence, second light)

[0225] LB blue light (fluorescence, third light)

[0226] LUV, LUV1~LUV3 ultraviolet light (excitation light, invisible light)

[0227] RSUB Red Display Subpixel (First Display Subpixel)

[0228] GSUB Green Display Subpixel (Second Display Subpixel)

[0229] BSUB Blue display subpixel (third display subpixel)

Claims

1. A control device that controls a display device, characterized by, The display device includes: a display panel having a display region in which a plurality of display pixels are arranged, and displaying an image based on an image signal; and a backlight having at least one light emitting region that irradiates the plurality of display pixels based on the image signal, the at least one light emitting region having at least one light emitting element as a light source, each of the plurality of display pixels having: a first display sub-pixel that displays a first color; a second display sub-pixel that displays a second color different from the first color; and a third display sub-pixel that displays a third color different from the first color and the second color, each of the at least one light emitting element having: an excitation light source that emits invisible light as excitation light; a first light emitting member that receives the invisible light and emits first light as fluorescent light, the first light being light of the first color; a second light emitting member that receives the invisible light and emits second light as fluorescent light, the second light being light of the second color and having a shorter peak wavelength than the first light; and a third light emitting member that receives the invisible light and emits third light as fluorescent light, the third light being light of the third color and having a shorter peak wavelength than the second light, each of the at least one light emitting element emitting, as mixed light, light obtained by mixing the first light, the second light, and the third light toward the plurality of display pixels, the control device includes: a backlight luminance calculation section that generates backlight luminance data based on the image signal; and a display pixel data generation section that generates display pixel data based on the backlight luminance data and the image signal, the display pixel data including: first display sub-pixel data corresponding to the first display sub-pixel; second display sub-pixel data corresponding to the second display sub-pixel; and third display sub-pixel data corresponding to the third display sub-pixel, the display pixel data generation section generating the first display sub-pixel data using a first time constant, generating the second display sub-pixel data using a second time constant different from the first time constant, and generating the third display sub-pixel data using a third time constant different from the first time constant.

2. The control device according to claim 1, characterized by the invisible light is ultraviolet light.

3. The control device of claim 1, wherein the first time constant is greater than the second time constant and the third time constant.

4. The control device of claim 3, wherein the second time constant is equal to the third time constant.

5. The control device of claim 4, wherein the second time constant and the third time constant are 0.

6. The control device according to any one of claims 1 to 5, characterized by the display pixel data generation section sets at least one of the first time constant, the second time constant, and the third time constant in accordance with a frame rate of the image.

7. The control device according to any one of claims 1 to 5, wherein the display pixel data generation section calculates a mixed light backlight luminance distribution based on the backlight luminance data, the mixed light backlight luminance distribution being a luminance distribution of the mixed light irradiated from the backlight toward each of the plurality of display pixels; and The display pixel data generating section calculates a first light backlight luminance distribution, which is a luminance distribution of the first light irradiated from the backlight to each of the plurality of display pixels, by smoothing the mixed light backlight luminance distribution using the first time constant; The display pixel data generating section calculates a second light backlight luminance distribution, which is a luminance distribution of the second light irradiated from the backlight to each of the plurality of display pixels, by smoothing the mixed light backlight luminance distribution using the second time constant; The display pixel data generating section calculates a third light backlight luminance distribution, which is a luminance distribution of the third light irradiated from the backlight to each of the plurality of display pixels, by smoothing the mixed light backlight luminance distribution using the third time constant; The display pixel data generating section generates the display pixel data based on the first light backlight luminance distribution, the second light backlight luminance distribution, the third light backlight luminance distribution, and the image signal.

8. The control device according to claim 7, wherein The display pixel data generating section generates the first display sub-pixel data based on the first light backlight luminance distribution and a luminance value of the first color in the image; The display pixel data generating section generates the second display sub-pixel data based on the second light backlight luminance distribution and a luminance value of the second color in the image; The display pixel data generating section generates the third display sub-pixel data based on the third light backlight luminance distribution and a luminance value of the third color in the image.

9. The control device of claim 7, wherein The second light backlight luminance distribution and the third light backlight luminance distribution are the same distribution.

10. The control device according to claim 7, wherein n is an arbitrary integer, The display pixel data generating section corrects the mixed light backlight luminance distribution in the nth frame of the image, according to a degree of divergence of the mixed light backlight luminance distribution in the nth frame of the image and the mixed light backlight luminance distribution in the (n-1)th frame of the image, and calculates the second light backlight luminance distribution and the third light backlight luminance distribution in the nth frame.

Images