Control device and display 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 first light emitting components that emit first light, second light emitting components that emit second light having a peak wavelength shorter than the first light, and third light emitting components that emit third light having a peak wavelength shorter than the second light. The first light emitting components are fluorescent components that receive the second light and / or the third light to emit the first light as fluorescent light. The control device generates pixel data for sub-pixels that display the first light using a first time constant, generates pixel data for sub-pixels that display the second light using a second time constant different from the first time constant, and generates pixel data for sub-pixels that display 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 that controls a display device having a plurality of light emitting components that respectively emit different colors. BACKGROUND

[0002] In recent years, various researches have been made on display devices that use a plurality of light emitting components (luminescent materials) that respectively emit different colors to achieve color display. For example, in Patent Literature 1, a technology for coping with a decrease in display quality of a display device caused by a difference in afterglow characteristics of the respective luminescent materials is disclosed. Specifically, in the technology of Patent Literature 1, an analog afterglow signal is added to an image signal corresponding to a luminescent material with a short afterglow time.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2005-141204 SUMMARY

[0006] Technical Problem to be Solved by the Invention

[0007] However, as described later, there is room for improvement in the specific method for improving the display quality of a display device. An aspect of the present disclosure aims to improve the display quality of a display device having a plurality of light emitting components that respectively emit different colors by a method different from the past.

[0008] Technical Solution to Solve the Technical Problem

[0009] To solve the above problems, one embodiment of the present disclosure relates to a control device that controls a display device, the display device including 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; a backlight having at least one light emitting region that irradiates the plurality of display pixels based on the image signal; each of the plurality of display pixels having (i) a first display sub-pixel that displays a first color, (ii) a second display sub-pixel that displays a second color different from the first color, and (iii) 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 (i) a first light emitting part that emits light of the first color, (ii) a second light emitting part that emits light of the second color and has a shorter peak wavelength than the light of the first color, and (iii) a third light emitting part that emits light of the third color and has a shorter peak wavelength than the light of the second color, the second light emitting part being a light source that emits the light of the second color, the third light emitting part being a light source that emits the light of the third color, the first light emitting part being a first phosphor part that receives excitation of the light of the second color and / or the light of the third color and emits the light of the first color as phosphor light; and the control device including a backlight luminance calculation part that generates backlight luminance data based on the image signal, and a display pixel data generation part that generates display pixel data based on the backlight luminance data and the image signal, the display pixel data including (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 part generating (i) the first display sub-pixel data using a first time constant, (ii) the second display sub-pixel data using a second time constant different from the first time constant, and (iii) the third display sub-pixel data using a third time constant different from the first time constant.

[0010] Advantageous Effects

[0011] According to one embodiment of the present disclosure, display quality of a display device having a plurality of light emitting parts that emit respective different colors can be improved by a method different from the related art. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a block diagram illustrating a configuration of a main part of a display device according to Embodiment 1.

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

[0014] Figure 3 FIG. 2 is a diagram showing a correspondence relationship between a light emitting region of a BL of Embodiment 1 and the light emitting element.

[0015] Figure 4 FIG. 3 is a diagram for explaining a luminance distribution of the light emitting element.

[0016] Figure 5 FIG. 4 is a diagram showing a configuration example of a BL luminance distribution color filter operation section in Embodiment 1.

[0017] Figure 6 FIG. 5 is a diagram showing an example of f(R) and f(G, B).

[0018] Figure 7 FIG. 6 is a diagram explaining a relationship among a BL luminance, a panel transmittance, and a display image luminance in an ideal display device.

[0019] Figure 8 FIG. 7 is a diagram explaining a relationship among a BL luminance, a panel transmittance, and a display image luminance in Comparative Example 1.

[0020] Figure 9 FIG. 8 is a diagram explaining a relationship among a BL luminance, a panel transmittance, and a display image luminance in Comparative Example 2.

[0021] Figure 10 FIG. 9 is a diagram explaining a relationship among a BL luminance, a panel transmittance, and a display image luminance in Display Device 1.

[0022] Figure 11 FIG. 10 is a block diagram showing a configuration of a main part of a display device in a modification example of Embodiment 1.

[0023] Figure 12 FIG. 11 is a diagram showing a configuration example of a BL luminance distribution color filter operation section in Display Device 2.

[0024] Figure 13 FIG. 12 is a diagram showing an example of a correction table in Embodiment 2.

[0025] Figure 14 FIG. 13 is a diagram explaining a relationship among a BL luminance, a panel transmittance, and a display image luminance in Reference Example.

[0026] Figure 15 FIG. 14 is a diagram explaining a relationship among a BL luminance, a panel transmittance, and a display image luminance in Display Device 2.

[0027] Figure 16is a block diagram showing a configuration of a main part of a display device according to Embodiment 3. DETAILED DESCRIPTION

[0028] (Embodiment 1)

[0029] Hereinafter, the display device 1 according to Embodiment 1 will be described. For the convenience of explanation, components having the same function as those described in Embodiment 1 are denoted by the same reference numerals in each of the following embodiments, and the description thereof will not be repeated. In addition, for the sake of simplicity, the description of matters common to the known art will also be appropriately omitted.

[0030] Note that each of the configurations and numerical values described in this specification is only an example unless specifically indicated. Therefore, the positional relationship of each component is not limited to the example of each drawing unless specifically indicated. In addition, it should be noted that each drawing schematically illustrates the shape, structure, and positional relationship of each component, and is not necessarily drawn to scale. In this specification, the expression "A and B" includes only A, only B, and both A and B unless specifically indicated. Such a description means "A or less and B or more" unless specifically indicated.

[0031] In this specification, the following abbreviations are used:

[0032] • BackLight: "BL"

[0033] • Local Dimming: "LD"

[0034] • ColorFilter: "CF"

[0035] • Electro-Luminescence: "EL"

[0036] • Photo-Luminescence: "PL".

[0037] In addition, "afterglow characteristics of a light-emitting material" described in this specification collectively indicates "a delay characteristic of a decrease in light intensity emitted from a light-emitting material" and "a delay characteristic of an increase in light intensity emitted from a light-emitting material". Therefore, in this specification, "afterglow time" collectively indicates "a delay time of a decrease in light intensity" and "a delay time of an increase in light intensity".

[0038] (Outline of Display Device 1)

[0039] Figure 1is a block diagram showing a configuration of a main part of the display device 1. The display device 1 is provided with a control section 10 (control device), an image signal acquisition section 20, and a display section 30. The display device 1 displays an image based on an image signal in accordance with a prescribed video standard. As an example of the prescribed video standard, an HDR (High Dynamic Range) standard can be cited. The display device 1 can be a terminal device of a portable type, or can also be a device of a stationary type.

[0040] The control section 10 controls each section of the display device 1 as a whole. As described below, the control section in one embodiment of the present disclosure processes an image signal supplied by the image signal acquisition section 20. Therefore, the control device in one embodiment of the present disclosure can also be called an image processing device. The control section 10 is provided with a BL luminance calculation section 11, a BL luminance color filter operation section 12, and a display pixel data generation section 13. The display pixel data generation section 13 has a BL luminance distribution calculation section 131, a BL luminance distribution color filter operation section 132, and a transmittance decision section 133. Examples of the operation of each section of the control section 10 will be described later.

[0041] The image signal acquisition section 20 acquires an image signal. As an example, the image signal acquisition section 20 acquires an image signal by decoding a broadcast signal received by the display device 1. As another example, the image signal acquisition section 20 can also acquire an image signal from an external device not shown which is communicably connected to the display device 1. As an example of the external device, a BD (Blu-lay (registered trademark) Disc) player can be cited. The image signal acquisition section 20 supplies the acquired image signal to the control section 10. As a specific example, as shown in Fig. 1, the image signal acquisition section 20 supplies the image signal to the BL luminance calculation section 11 and the transmittance decision section 133.

[0042] The display section 30 is, for example, a liquid crystal display. The display section 30 is provided with a BL 31 and a display panel 35. The display panel 35 is an example of a display panel to which one embodiment of the present disclosure is directed. The display panel 35 has a plurality of display pixels 350 (example: liquid crystal pixels) whose light transmittance (hereinafter, simply referred to as transmittance) can be controlled. Specifically, the display panel 35 has I1 x J1 display pixels 350. I1 represents the number of display pixels per row, and J1 represents the number of display pixels per column. Both I1 and J1 are integers of 2 or more. In this way, the display pixels 350 are arranged in a two-dimensional matrix shape in a display region (a region in which an image is displayed) of the display panel 35. The transmittance of the display pixels 350 is controlled in accordance with an image signal.

[0043] The display pixel 350 has a plurality of display sub-pixels for color display of an image. In Embodiment 1, the display pixel 350 has: (i) a first display sub-pixel that displays a first color, (ii) a second display sub-pixel that displays a second color, (iii) a third display sub-pixel that displays a third color. The first color to the third color are different colors, respectively. In Embodiment 1, a case where the first color is red, the second color is green, and the third color is blue is exemplified. However, of course, the first color to the third color are not limited to this example.

[0044] In Embodiment 1, the display pixel 350 has: (i) a red display sub-pixel (a display sub-pixel that displays red) as the first display sub-pixel, (ii) a green display sub-pixel (a display sub-pixel that displays green) as the second display sub-pixel, (iii) a blue display sub-pixel (a display sub-pixel that displays blue) as the third display sub-pixel. In the following description, the red display sub-pixel is abbreviated as RSUB, the green display sub-pixel is abbreviated as GSUB, and the blue display sub-pixel is abbreviated as BSUB, respectively.

[0045] The BL 31 irradiates the display pixel 350. The BL 31 in Embodiment 1 is an example of a BL having an LD function. Therefore, the BL 31 has a plurality of light emitting regions 305 that can be controlled independently of each other with respect to luminance (refer to FIG. 4 described later). Figure 3 ) In the example of FIG. 3, the BL 31 is disposed on the back surface of the display panel 35. However, the BL 31 can be disposed anywhere as long as the BL 31 can irradiate the display pixel 350. Therefore, the disposition of the BL 31 is not limited to the example of FIG. 3. Figure 1 Figure 1

[0046] The BL 31 has I2 x J2 light emitting regions 305. I2 indicates the number of light emitting regions per row, and J2 indicates the number of light emitting regions per column. In the example of Embodiment 1, I2 and J2 are each an integer of 2 or more. In this way, the BL 31 in Embodiment 1 is configured of a plurality of light emitting regions 305 that are two-dimensionally divided. Due to this, the BL 31 in Embodiment 1 can also be referred to as a BL of a two-dimensional dimming type.

[0047] However, the BL 31 can also have a plurality of light emitting regions 305 that are one-dimensionally divided. That is, one of I2 or J2 can be 1. For example, the BL 31 can be divided into 1 x J2 light emitting regions 305. Alternatively, the BL 31 can be divided into I2 x 1 light emitting 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 2As shown, the light emitting element 310 is provided with an excitation light source 320, a phosphor member 330 (wavelength conversion member), and a CF member 340. The excitation light source 320 includes a green light source 360 and a blue light source 370. The green light source 360 is provided with, in order from the upper side, a substrate 321, a first electrode 322, a hole injection layer 323, a hole transport layer 324, a green QD (Qunatum Dot) layer 325, an electron transport layer 326, and a second electrode 327. The blue light source 370 is provided with, in order from the upper side, the substrate 321, the first electrode 322, the hole injection layer 323, the hole transport layer 324, a blue QD (Qunatum Dot) layer 425, the electron transport layer 326, and the second electrode 327. In Figure 2 The first electrode 322 and the second electrode 327 in the example of FIG. 1 are an anode and a cathode, respectively. The second electrode 327 has a light-transmitting property in a manner capable of transmitting green light (for convenience, referred to as LG) emitted from the green QD layer 325 or blue light (for convenience, referred to as LB) emitted from the blue QD layer 425.

[0054] The green QD layer 325 is a light emitting layer (green QD phosphor particle layer) containing green QD phosphor particles, which are not shown. In the green light source 360, 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 green QD phosphor particles emit LG as the holes and the electrons are recombined. In this way, the QD layer 325 emits light by EL (more specifically, injection-type EL). As an example, the wavelength range of the LG is 522 nm to 542 nm, and the peak wavelength of the LG is 532 nm.

[0055] The blue QD layer 425 is a light emitting layer (blue QD phosphor particle layer) containing blue QD phosphor particles, which are not shown. As in the green light source 360, the blue QD phosphor particles in the blue light source 370 emit LB as the holes and the electrons are recombined. In this way, the QD layer 425 emits light by EL (more specifically, injection-type EL). As an example, the wavelength range of the LB is 457 nm to 477 nm, and the peak wavelength of the LB is 467 nm.

[0056] In the excitation light source 320, the QD layer 325, the QD layer 425, and the respective layers corresponding thereto are arranged in a manner such that the LG and the LB are emitted in a direction perpendicular to the substrate 321. Figure 2The excitation light source 320 is divided into three partial regions (SEC1 to SEC3) in the horizontal direction. More specifically, in the excitation light source 320, a plurality of switching elements are provided in SEC1 to SEC3 in a manner that enables separate application of voltage to the QD layer 325 and the QD layer 425. As an example of the switching element, a thin film transistor (TFT) can be given. Thus, the light emission state of the QD layer 325 and the QD layer 425 can be individually controlled in each of SEC1 to SEC3. Hereinafter, the LG emitted from SEC1 and SEC2 will be referred to as LG1 and LG2, respectively. In Figure 2 In the example of FIG. 3, SEC1 is set as RSUB, SEC2 is set as GSUB, and SEC3 is set as a partial region corresponding to BSUB, respectively.

[0057] The phosphor member 330 is provided above the excitation light source 320 at positions corresponding to SEC1 to SEC3. The phosphor member 330 converts the wavelength of a portion (LG1) of the LG emitted from the QD layer 325. More specifically, the phosphor member 330 receives LG1 as excitation light and emits fluorescent light of a color different from green (second color). In Embodiment 1, the phosphor member 330 emits fluorescent light of red (first color). In addition, in Embodiment 1, excitation light of green (second color) and blue (third color) is emitted by the excitation light source 320. More specifically, excitation light of green is emitted from the SEC2 portion of the green light source 360, and excitation light of blue is emitted from the blue light source 370.

[0058] In the present specification, light of the first color to light of the third color will be referred to as first light to third light, respectively. In addition, the second light has a peak wavelength shorter than that of the first light. Further, the third light has a peak wavelength shorter than that of the second light. Then, in the present specification, a member that emits the first light to the third light will be referred to as a first light emitting member to a third light emitting member, respectively. Further, a member that emits the first light to the third light as fluorescent light will be referred to as a first phosphor member to a third phosphor member, respectively. A member that emits the first light to the third light as fluorescent light will be referred to as a first phosphor member to a third phosphor member, respectively. A member that emits the first light to the third light as fluorescent light will be referred to as a first phosphor member to a third phosphor member, respectively. A member that emits the first light to the third light as fluorescent light will be referred to as a first phosphor member to a third phosphor member, respectively.

[0059] In Embodiment 1, the red phosphor member 331R described below is an example of the first light emitting member (more specifically, the first phosphor member). Thus, in Embodiment 1, the red phosphor member 331R is an example of the first light emitting member (more specifically, the first phosphor member). Thus, in Embodiment 1, the green light source 360 included in the excitation light source 320 is an example of the second light emitting member, and the blue light source 370 included in the excitation light source 320 is an example of the third light emitting member. Thus, Figure 2 In Embodiment 1, the red phosphor member 331R described below is an example of the first light emitting member (more specifically, the first phosphor member). Thus, in Embodiment 1, the green light source 360 included in the excitation light source 320 is an example of the second light emitting member, and the blue light source 370 included in the excitation light source 320 is an example of the third light emitting member. Thus, Figure 2LG (more specifically, LG2) is an example of the second light, and LB is an example of the third light.

[0060] The phosphor member 330 has a red phosphor member 331R (red wavelength conversion member). The red phosphor member 331R is provided at a position corresponding to the SEC1. The red phosphor member 331R contains red QD phosphor particles not shown. The red QD phosphor particles receive LB1 as excitation light, and thereby emit red light (LR) as fluorescent light. In this way, the red phosphor member 331R converts LB1 to LR having a peak wavelength longer than that of LB1. As an example, the wavelength range of LR is 620 nm to 640 nm, and the peak wavelength of LR is 630 nm. In the example shown in FIG. 3, the LR of the red CF 341R described below is emitted to the display panel 35 in the SEC1. Figure 2

[0061] As described above, the red phosphor member 331R emits light by PL unlike the green QD layer 325 and the blue QD layer 425. The light amount of LR can be changed by adjusting the light amount of LG1 as excitation light. In addition, the afterglow time of LB and LG (fluorescent light generated by EL) is shorter than that of LR (fluorescent light generated by PL).

[0062] As shown in FIG. 3, the phosphor member 330 further has a green light transmission layer 331G at a position corresponding to the SEC2. The green light transmission layer 331G transmits LG2. The material of the green light transmission layer 331G is not particularly limited, but is preferably a material having particularly high light transmittance at least in the green wavelength band (for example, glass or resin having light transmittance). Figure 2

[0063] In addition, in the example shown in FIG. 3, the phosphor member 330 further has a blue light transmission layer 331B at a position corresponding to the SEC3. The blue light transmission layer 331B transmits LB. The material of the blue light transmission layer 331B is not particularly limited, but is preferably a material having particularly high light transmittance at least in the blue wavelength band (for example, glass or resin having light transmittance). Figure 2 ​​In the example of FIG. 3, the CF member 340 also has a green light transmitting layer 341G, which is the same as the green light transmitting layer 331G described above, at a position corresponding to the SEC2. Thus, the LG2 that has passed through the green light transmitting layers 331G, 341G is emitted toward the display panel 35. However, in the light emitting element 310, a green CF can also be further provided instead of the green light transmitting layer 341G of the CF member 340. In addition, the CF member 340 has a blue light transmitting layer 341B, which is the same as the blue light transmitting layer 331B described above, at a position corresponding to the SEC3. Thus, the LB3 that has passed through the blue light transmitting layers 331B, 341B is emitted toward the display panel 35. However, in the light emitting element 310, a blue CF can also be further provided instead of the blue light transmitting layer 341B of the CF member 340.

[0064] As described above, according to the light emitting element 310, it is possible to supply the display panel 35 with light (mixed light) that is a mixture of the LR, the LG2, and the LB. Thus, by appropriately adjusting the light amounts of the LR, the LG2, and the LB, respectively, it is possible to express a desired color tone using the mixed light. In Embodiment 1, a case in which the light emitting element 310 emits white light (more strictly, light that is approximately white light) as the mixed light is exemplified. This is the same as in Embodiment 3 described later.

[0065] Further, in the light emitting element 310, by using the green QD layer 325 as a green light source and the blue QD layer 425 as a blue light source, it is possible to precisely control the half-value width and the fluorescence peak wavelength of the green light and the blue light. That is, it is possible to improve the monochromaticity of the green light (LG2) in the GSUB and the blue light (LB) in the BSUB, respectively. Likewise, by using the red phosphor member 331R as a red light source, it is possible to improve the monochromaticity of the red light (LR) in the RSUB. Thus, according to the light emitting element 310, it is possible to realize a display device 1 that is excellent in display quality (particularly, color reproducibility).

[0066] However, the phosphor member 330 does not necessarily convert all of the LG1 received in the SEC1 into light of a different wavelength. Specifically, the red phosphor member 331R does not necessarily convert all of the LG1 into the LR. That is, a part of the LG1 passes through the red phosphor member 331R without being absorbed by the red phosphor member 331R. Hereinafter, the LG1 that has passed through the red phosphor member 331R will be referred to as residual green light.

[0067] Thus, in the light emitting element 310 of the example of FIG. 3, in order to reduce the influence of the residual green light, the CF member 340 is provided above the phosphor member 330. More specifically, the CF member 340 is provided so as to cover the phosphor member 330 as viewed from the display surface of the display panel 35. Figure 2 In the light emitting element 310 of the example of FIG. 3, in order to reduce the influence of the residual green light, the CF member 340 is provided above the phosphor member 330. More specifically, the CF member 340 is provided so as to cover the phosphor member 330 as viewed from the display surface of the display panel 35.

[0068] The CF member 340 has a red CF 341R. In order to reduce the influence of the residual green light in the Rsub, the red CF 341R is provided at a position corresponding to the SEC1 (a position corresponding to the red phosphor member 331R).

[0069] The red CF 341R has a high light transmittance in the red wavelength band, and has a relatively low light transmittance in other wavelength bands. It is preferable that the red CF 341R has a particularly low transmittance in the green wavelength band.

[0070] By providing the CF member 340, it is possible to block the residual green light from reaching the display surface, using the red CF 341R. Therefore, it is possible to further improve the monochromaticity of the LR in the display portion 30. Therefore, it is possible to further improve the display quality of the display device 1. However, depending on the display quality required of the display device 1, the CF member 340 can be omitted. This is the same for the CF member 440 of Embodiment Mode 3 described later.

[0071] Of course, the configuration of the light emitting element 310 is not limited to Figure 2 . The light emitting element 310 can be realized by any configuration known in the art. For example, the light emitting element 310 can be realized by a simpler configuration than Figure 2 . As an example, the light emitting element 310 can be a light emitting element in which a green LED (green excitation light source), a blue LED (blue excitation light source), and a red phosphor member (red wavelength conversion member) are sealed in one package.

[0072] In addition, in the light emitting element 310 exemplified in Figure 3 , the configuration is such that the red phosphor member 331R is excited by the light of the green light source 360 to generate fluorescent light, thereby obtaining the red light LR. However, this is not limiting, and for example, the configuration can be such that the red phosphor member 331R is excited by the light of the blue light source 370 to generate fluorescent light, thereby obtaining the red light LR. In addition, for example, the configuration can be such that the red phosphor member 331R is excited by both the light of the green light source 360 and the light of the blue light source 370 to generate fluorescent light, thereby obtaining the red light LR. That is, the third light emitting member can be a light source (blue light source 370) that emits third light, the second light emitting member can be a light source (green light source 360) that emits second light, and the first light emitting member can be a first phosphor member (red phosphor member 331R) that receives the third light and / or the second light to be excited and emits first light as fluorescent light.

[0073] (Example of luminance distribution of light emitting element 310)

[0074] Figure 3is a view showing the correspondence relationship between the light emitting regions 305 and the light emitting elements 310 in the BL 31. As described above, in the example of Figure 3 one light emitting region 305 corresponds to one light emitting element within the light emitting region 305. In the example of Figure 3 the positions in the row direction in the BL 31 are respectively denoted by a subscript i, and the positions in the column direction are respectively denoted by a subscript j. i is an integer satisfying 1≤i≤I2. j is an integer satisfying 1≤j≤J2.

[0075] The row direction and the column direction in the BL 31 correspond to the row direction (vertical direction) and the column direction (horizontal direction) of the influence, respectively. Therefore, the row direction and the column direction in the BL 31 also correspond to the row direction and the column direction in the display panel 35, respectively. In the example of Figure 3 the light emitting region 305 located at the ith row and the jth column in the BL 31 is denoted as REG(i, j). Further, the light emitting element 310 possessed by REG(i, j) is denoted as LS(i, j). In the example of Figure 3 white circles respectively denote the light emitting elements 310 in the lighted state (light emitting state), and black circles denote the light emitting elements 310 in the unlit state (non-light emitting state).

[0076] As described above, in the display device 1, the luminance of the light emitting element 310 is controlled in accordance with the image signal. Further, in the following description, "the luminance of the light emitting element 310" can be appropriately replaced with "the luminance of the light emitting region 305". As an example, consider the case where the image represented by the image signal is a white window pattern having a black background. In this case, the control section 10 causes the light emitting elements 310 existing at the positions corresponding to the white window pattern to be lighted.

[0077] In the example of Figure 4 a 3x3 rectangular region centered on REG(3, 5) corresponds to the white window pattern. In this case, the control section 10 causes the following nine light emitting elements to be lighted:

[0078] LS(2, 4), LS(2, 5), LS(2, 6):

[0079] LS(3, 4), LS(3, 5), LS(3, 6):

[0080] LS(4, 4), LS(4, 5), LS(4, 6).

[0081] On the other hand, the control section 10 causes the light emitting elements 310 other than the nine light emitting elements to be unlit.

[0082] Figure 4 is a view for explaining the luminance distribution of the light emitting elements 310. Figure 4The reference sign 4100 in FIG. 4A indicates an example of a two-dimensional luminance distribution of one light emitting element 310 in the lighted state. As indicated by the reference sign 4100, the luminance of the light emitting element 310 takes a peak value at the center position of the light emitting element 310, and decreases as it moves away from the center position. In the display device 1, the luminance distribution is modeled by a PSF (Point Spread Function) set in advance. Figure 4 The reference sign 4200 in FIG. 4B indicates a graph that represents the luminance distribution in the reference sign 4100 by a one-dimensional graph. As an example, the horizontal axis "Position" of the graph indicates the position in the row direction or the column direction of the BL 31. In this case, the graph shows the luminance distribution of one light emitting element 310 in the row direction or the column direction of the BL 31.

[0083] Figure 1 The reference sign 4300 in FIG. 4C is a graph that indicates one-dimensional luminance distributions of a plurality of (for example, three) light emitting elements 310 in the lighted state. The graph of the reference sign 4300 is paired with the graph of the reference sign 4200. As an example, in the following description, let LS(2, 4), LS(2, 5), and LS(2, 6) be the above three light emitting elements 310.

[0084] DisA, DisB, and DisC in the reference sign 4300 respectively indicate the luminance distributions of LS(2, 4), LS(2, 5), and LS(2, 6). As indicated by the reference sign 4300, DisB is obtained by shifting DisA to the right by only one share of the light emitting element 310. Similarly, DisC is obtained by shifting DisB to the right by only one share of the light emitting element 310. In other words, DisC is obtained by shifting DisA to the right by only two shares of the light emitting element 310.

[0085] In the display device 1, the PSF that respectively shows is set in advance. Also, in the display device 1, the luminance distribution of the above three light emitting elements 310 (DisT in the graph of the reference sign 4300) is calculated by performing an operation of adding DisA, DisB, and DisC.

[0086] In the display device 1, the distribution of the luminance of the light that is irradiated from the BL 31 to each of the plurality of display pixels 350 (BL luminance distribution) is calculated on the basis of the PSF by a known calculation model. The calculation model is constructed to reproduce the actual luminance distribution of the BL 31. As described below, in the display device 1, the display panel 35 is controlled on the basis of the BL luminance distribution in addition to the image signal.

[0087] (BL luminance calculation section 11)

[0088] Referring again toFigure 5 The operation of each section of the control section 10 will be described. The BL brightness calculating section 11 generates BL brightness data based on the image signal acquired from the image signal acquiring section 20. The BL brightness data is data indicating the brightness of the BL 31 in each frame period of the image.

[0089] As described above, the BL 31 in Embodiment 1 is an LD-type BL. Therefore, the BL brightness calculating section 11 generates BL brightness data for the LD-type BL based on the image signal. In a specific example, the BL brightness calculating section 11 generates BL brightness data indicating the brightness of the LS(I1, J1) to LS(I2, J2) in each frame period. The BL brightness calculating section 11 supplies the generated BL brightness data to the BL brightness filter operating section 12.

[0090] (BL brightness filter operating section 12)

[0091] The BL brightness filter operating section 12 corrects the BL brightness data using a known filter (for example, a digital filter). More specifically, the BL brightness filter operating section 12 smoothes the BL brightness data using the filter. Hereinafter, the BL brightness data corrected by the BL brightness filter operating section 12 will be referred to as corrected BL brightness data. The BL brightness filter operating section 12 supplies the corrected BL brightness data to the BL 31 and the BL brightness distribution calculating section 131.

[0092] The filter in the BL brightness filter operating section 12 is not particularly limited as long as it can smooth the BL brightness data. For example, the filter can delay the temporal change of the BL brightness data according to an arbitrarily set time constant. Therefore, for example, a known low-pass filter can be applied as the filter for smoothing the BL brightness data.

[0093] As a specific example of the filter described above, an IIR (Infinite Impulse Response) filter or an FIR (Finite IR) filter can be given. In addition, in order to reduce the amount of operation in the filter, it is preferable to adopt an IIR filter. The description of the filter in the BL brightness filter operating section 12 is also equally applicable to the BL brightness distribution filter operating section 132 described later.

[0094] In general, the response speed of the display panel 35 (panel response speed) is lower than the response speed of the BL 31 (BL response speed). Therefore, in a case where the BL 31 is driven in accordance with the BL luminance data, flicker can occur in the display portion 30 due to the difference between the BL response speed and the panel response speed. In particular, in a case where a scene change occurs in the video, the likelihood of flicker occurring is high. This degrades the display quality of the video displayed on the display portion 30, and thus is not preferable for the display device 1.

[0095] Therefore, in Embodiment 1, the control portion 10 drives the BL 31 in accordance with the BL luminance data after the correction. As a specific example, the control portion 10 drives the LS(1, 1) to the LS(I2, J2) in accordance with the corrected BL luminance data. By driving the BL 31 in this way, it is possible to reduce the difference between the BL response speed and the panel response speed. Therefore, it is possible to improve the display quality of the video displayed on the display portion 30.

[0096] (BL luminance distribution calculating portion 131)

[0097] Next, each portion of the display pixel data generating portion 13 will be described. The BL luminance distribution calculating portion 131 calculates the BL luminance distribution based on (i) the corrected BL luminance data acquired from the BL luminance filter calculating portion 12 and (ii) a PSF set in advance.

[0098] In the display device 1, the PSF is set with respect to the color of the mixed light (for convenience, referred to as mixed color) emitted from the light emitting element 310. As described above, the mixed color in the example of Embodiment 1 is white. Therefore, in Embodiment 1, the display pixel data generating portion 13 calculates the BL luminance distribution of white light. In this specification, the BL luminance distribution of white light is denoted by f(W). f(W) is an example of the mixed light BL luminance distribution involved in one embodiment of the present disclosure. The mixed light BL luminance distribution means the distribution of the luminance of the mixed light irradiated from the BL 31 to each of the plurality of display pixels 350. The display pixel data generating portion 13 supplies f(W) calculated during each frame to the BL luminance distribution filter calculating portion 132.

[0099] (BL luminance distribution filter calculating portion 132)

[0100] Figure 5is a diagram showing a configuration example of the BL brightness distribution filter operation section 132. The BL brightness distribution filter operation section 132 smoothes f(W) using a known filter, thereby calculating a first light BL brightness distribution, a second light BL brightness distribution, and a third light BL brightness distribution. The first light BL brightness distribution refers to a brightness distribution of the first light that is respectively irradiated from the BL 31 to the plurality of display pixels 350. The same definition applies to the second light BL brightness distribution and the third light BL brightness distribution. The BL brightness distribution filter operation section 132 supplies the calculated first light BL brightness distribution to the transmittance decision section 133. The third light BL brightness distribution is supplied to the transmittance decision section 133.

[0101] In Figure 5 In the example, the BL brightness distribution filter operation section 132 smoothes f(W) by the IIR filter. Figure 5 In the example, the BL brightness distribution filter operation section 132 smoothes f(W) by the IIR filter.

[0102] H(z) = a0 / (1 - bl x z -1 )... (1)

[0103] The transfer function H(z) represented by the above expression smoothes f(W). Further, a0= 1 / (1 + bl). Further, 0 < bl < 1.

[0104] Figure 6 The BL brightness distribution filter operation section 132 of the BL brightness distribution filter operation section 132 in the example has amplifiers 1321a, 1321b, a frame delay circuit 1322, and an adder 1323. As is clear to those skilled in the art, these functional sections are connected to each other to realize H(z) of expression (1). The respective gains of the amplifiers 1321a, 1321b are a0and bl. These gains are variable. The frame delay circuit 1322 outputs data held during the previous frame during the next frame.

[0105] Here, a time constant of the filter having the transfer function of expression (1) is represented as τ. As is clear to those skilled in the art, between τ and bl,

[0106] bl = exp(-t / τ)... (2)

[0107] This relationship holds. t is a frame period of the image. t is the inverse of the frame rate f of the image. In Embodiment 1, f = 120 Hz. Therefore, in Embodiment 1, t = 8.34 ms. As is clear from expression (2), in the BL brightness distribution filter operation section 132, by appropriately selecting the value of bl, a desired τ can be obtained.

[0108] For example, consider the case where τ = 10 ms is set in the BL luminance distribution filter operation section 132. In this case, bl = exp(-0.834) = 0.434 can be set. Thus, a0 = 1 / (1.434) = 0.697 can be set. In this way, by adjusting the respective gains of the amplifiers 1321a, 1321b, τ can be set to a desired value.

[0109] The BL luminance distribution filter operation section 132 can be configured to adjust the respective gains of the amplifiers 1321a, 1321b so as to correspond to a desired τ according to Equation (2). In other words, the BL luminance distribution filter operation section 132 can also set τ according to the frame rate. In this way, the BL luminance distribution filter operation section 132 can also be configured to be able 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.

[0110] It is known that in most cases (particularly in cases where a luminescent material having excellent monochromaticity is used), the afterglow time of light having a long wavelength is longer than the afterglow time of light having a short wavelength. Thus, for example, in most cases, the afterglow time of the first light (e.g., LR) is longer than the afterglow times 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 about 100 to 1000 times longer than the afterglow times of LG and LB. More specifically, the afterglow time of LR is about several tens of ms.

[0111] 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 the afterglow of LR. Thus, in Embodiment 1, the BL luminance distribution filter operation section 132 smoothes f(W) by H(z) and thereby calculates the red light BL luminance distribution f(R). f(R) is an example of a first light BL luminance distribution.

[0112] Figure 6 An example of f(R) calculated by the BL luminance distribution filter operation section 132 is shown. Figure 5 The horizontal axis in the graph of f(R) is the time. Figure 5 f(W) in the example of Fig. 6 is a step function that takes a High value (corresponding to the lighting of the luminescent element 310) during the period from time t1 to t2. Figure 5 As shown in Fig. 6, f(R) is calculated as a function representing a first-order lag response in which f(W) is delayed by the time constant τ.

[0113] 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.

[0114] 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).

[0115] As from Figure 6 as well as Figure 6 As understood, in Embodiment 1, the BL luminance distribution color filter calculation unit 132 makes

[0116] f(G)=f(B)=f(G,B)=f(W)…(3)

[0117] 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.

[0118] 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.

[0119] 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).

[0120] In a case where the second light BL luminance distribution and the third light BL luminance distribution are set as the second / third light BL luminance distribution, the second time constant is equal to the third time constant. However, of course, the second time constant and the third time constant can also be set to different values. For example, the second time constant can also be set to a value larger than the third time constant.

[0121] 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 time constant and the third time constant. In view of this, in Embodiment 1, f(G) and f(B) of the above-described formula (3) are set. In this case, as can be understood from the above description, τG= τB= τ(G, B) = 0 ms (time constant zero) is set. τ(G, B) is a time constant common to green light and blue light. τ(G, B) is referred to as a green / blue light time constant. Figure 5

[0122] As described above, in Embodiment 1, the BL luminance distribution filter operation section 132 does not delay f(W) but outputs f(W) directly as f(G, B) (also refer to the above-described description of Figure 5 ). In other words, the BL luminance distribution filter operation section 132 generates f(G, B) by applying a filter (identity filter) having a transfer function C(z) = 1 to f(W). The identity filter can also be expressed as a filter having a time constant of 0 and a gain of 1.

[0123] In addition, in the present specification, “the BL luminance distribution filter operation section 132 applies an identity filter to f(W) to generate f(G, B)” also includes “the BL luminance distribution filter operation section 132 does not delay f(W) but outputs f(W) directly as f(G, B)”. Thus, it is desirable to note that the identity filter is not necessarily installed as an actual hardware element or a software element in the BL luminance distribution filter operation section 132 (also refer to the above-described description of Figure 1 ).

[0124] (Transmittance determination section 133)

[0125] The transmittance determination section 133 (i) acquires the image signal from the image signal input section, and (ii) acquires the first light BL luminance distribution to the third light BL luminance distribution from the BL luminance distribution filter operation section 132. The transmittance determination section 133 acquires the image signal and f(R) and f(G, B) in the example of Figure 7 . The transmittance determination section 133 generates display pixel data (example: liquid crystal pixel data) based on the image signal and the first light BL luminance distribution to the third light BL luminance distribution. The display pixel data refers to data indicating the transmittance of each of the plurality of display pixels 350. ​

[0126] In Embodiment 1, the transmittance decision section 133 generates display pixel data including first display sub-pixel data (example: red display sub-pixel data), second display sub-pixel data (example: green display sub-pixel data), and third display sub-pixel data (example: blue display sub-pixel data). The first display sub-pixel data refers to data indicating the transmittance of each of the plurality of first display sub-pixels. The same definition applies to the second display sub-pixel data and the third display sub-pixel data.

[0127] The transmittance decision section 133 obtains the luminance value of each of the first to third colors in the image from the image signal. In Embodiment 1, the transmittance decision section 133 obtains the luminance value d(R) of red, the luminance value d(G) of green, and the luminance value d(B) of blue in the image.

[0128] Also, the transmittance decision section 133 decides the transmittance g(R) of the red display sub-pixel based on d(R) and f(R). In Embodiment 1, the transmittance decision section 133 calculates g(R) by dividing d(R) by f(R). That is, the transmittance decision section 133 calculates g(R) so that

[0129] g(R) = d(R) / f(R) … (4)

[0130] g(R) is calculated.

[0131] Similarly, the transmittance decision section 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).

[0132] Thus, the transmittance decision section calculates g(G) and g(B) so that

[0133] g(G) = d(G) / f(G) = d(G) / f(G) / f(G, B) … (5)

[0134] g(B) = d(B) / f(B) = d(B) / f(G, B) … (6)

[0135] g(G) and g(B) are respectively calculated.

[0136] The transmittance decision section 133 respectively generates (i) data indicating g(R) as the red display sub-pixel data, (ii) data indicating g(G) as the green display sub-pixel data, and (iii) data indicating g(B) as the blue display sub-pixel data.

[0137] The control section 10 drives the display panel 35 in accordance with the display pixel data. Specifically, the control section 10 drives each of the plurality of display pixels 350 in accordance with the display pixel data. More specifically, the control section 10 drives the RSUB, GSUB, and BSUB of each of the plurality of display pixels 350 in accordance with the red display sub-pixel data, the green display sub-pixel data, and the blue display sub-pixel data.

[0138] As described above, the display pixel data generation section 13 generates the display pixel data based on the BL luminance data and the image signal (in the example of Embodiment 1, based on the corrected BL luminance data and the image signal). Thus, in the display device 1, the display panel 35 can be driven in coordination with the driving of the BL 31. In addition, the display pixel data generation section 13 generates the red display sub-pixel data, the green display sub-pixel data, and the blue display sub-pixel data using different time constants of τR= 10 ms and τ(G, B) = 0 ms. Thus, in the display device 1, the display panel 35 can be driven so as to eliminate the influence of the difference in the afterglow time of each color light. For example, in the display device 1, the display panel 35 can be driven so as to eliminate the influence of the afterglow of LR.

[0139] (EFFECTS)

[0140] Figure 7 is a graph illustrating the relationship between the BL luminance, the panel transmittance (the transmittance of the display panel), and the display image luminance (the luminance of the image displayed by the display panel) in an ideal display device. In this ideal display device, the afterglow time of the red light, the green light, and the blue light is 0. Figure 7 The liquid crystal transmittance in

[0141] Figure 7 The graph G11 of illustrates an example of the time variation of the BL luminance in an ideal display device. In the example of G11, the BL luminance takes a High value at times t1 to t2. As an example, in the case where t1 to t2 are the period during which a bright scene of the display image is displayed, such a time variation of the BL luminance occurs. On the other hand, as illustrated in the graph G12 of Figure 8 As illustrated in the graph G12, the panel transmittance is constant regardless of the time. In the following Figure 9 and Figure 7 In the following description of

[0142] Figure 8The graph G13 shows an example of the time variation of the display image luminance in an ideal display device. The display image luminance is defined by the product of the BL luminance and the panel transmittance. Therefore, as shown in G13, in the ideal display device (i.e., in the case where the afterglow time of the red light, the green light, and the blue light are all equal), the manner of the time variation of the display image luminance coincides with the manner of the time variation of the BL luminance.

[0143] Figure 8 The graph G21 shows an example of the time variation of the BL luminance in Comparative Example 1. In G21, the solid line indicates the green-blue light, and the broken line indicates the red light. This is the same in each of the graphs hereinafter. As shown in G21, in tl, the green-blue light luminance (the luminance of the green-blue light) rapidly rises to the High value. On the other hand, the red light luminance (the luminance of the red light) increases slowly compared with the green-blue light luminance. In the example of G21, at time tl a, the red light luminance reaches the High value (see the portion S210 of G21). Thus, in Comparative Example 1, tl to tl a is a period in which the influence of the green-blue light is greater than that of the red light.

[0144] Figure 8 The graph G21 shows an example of the time variation of the BL luminance in Comparative Example 1. In G21, the solid line indicates the green-blue light, and the broken line indicates the red light. This is the same in each of the graphs hereinafter. As shown in G21, in tl, the green-blue light luminance (the luminance of the green-blue light) rapidly rises to the High value. On the other hand, the red light luminance (the luminance of the red light) increases slowly compared with the green-blue light luminance. In the example of G21, at time tl a, the red light luminance reaches the High value (see the portion S210 of G21). Thus, in Comparative Example 1, tl to tl a is a period in which the influence of the green-blue light is greater than that of the red light. Figure 8 Figure 8 In the example of G21, at time tl a, the red light luminance reaches the High value (see the portion S210 of G21). Thus, in Comparative Example 1, tl to tl a is a period in which the influence of the green-blue light is greater than that of the red light.

[0145] After that, in t2, the green-blue light luminance rapidly decreases to the Low value. On the other hand, the red light luminance decreases slowly compared with the green-blue light luminance. In the example of G21, at time t2a, the red light luminance reaches the Low value (see the portion S211 of G21). Thus, in Comparative Example 1, t2 to t2a is a period in which the influence of the red light is greater than that of the green-blue light. Figure 8

[0146] Figure 9 The graph G23 shows an example of the time variation of the display image luminance in Comparative Example 1. The manner of the time variation of the luminance of each color light in the display image is defined by the product of each color luminance of the BL light and the panel transmittance. Therefore, in tl to tl a, even in the display image, the green-blue light luminance is greater than the red light luminance. As a result, in tl to tl a, the display image produces a green-blue coloration (see the portion S230 of G23) corresponding to the above-described S210. Similarly, in t2 to t2a, the display image produces a red coloration (see the portion S231 of G23) corresponding to the above-described S211.

[0147] ​​Figure 9 is a graph that explains the relationship between the BL luminance, the panel transmittance, and the display image luminance in the display device of Patent Literature 1 (for convenience, referred to as Comparative Example 2). The display device of Patent Literature 1 is an example of a technology for solving the problem points in Comparative Example 1. Specifically, the display device of Patent Literature 1, in order to reduce the coloring of the display image, adds an analog afterglow signal to the image signal. In other words, the display device of Patent Literature 1, in order to reduce the coloring of the display image, causes the BL to generate an analog afterglow signal (analog afterglow).

[0148] Figure 9 The graph G31 of Comparative Example 2 shows an example of the time variation of the BL luminance in Comparative Example 2. As shown in G31, in Comparative Example 2, in tl to tla, in order to completely eliminate the influence of the delay in the rise of the red luminance, an analog afterglow of green and blue (refer to the portion S310 of G31) is added in a manner that reproduces the delay in the rise of the analog emission of green and blue. In addition, in Comparative Example 2, in t2 to t2m, in order to reduce (partially eliminate) the influence of the delay in the fall of the red luminance, an analog afterglow of green and blue (refer to the portion S311 of G31) is added in a manner that reproduces the delay in the fall of the analog emission of green and blue. t2m < t2a.

[0149] Figure 10 The graph G33 of Comparative Example 2 shows an example of the time variation of the display image luminance in Comparative Example 2. In Comparative Example 2, in tl to tla, the coloring of green and blue in the display image is eliminated in correspondence with the above-described S310 (refer to the portion S330 of G33). In addition, in Comparative Example 2, in t2 to t2a, the coloring of red in the display image is reduced in correspondence with the above-described S311. In this way, in Comparative Example 2, the coloring in the display image is reduced (refer to the portion S331 of G33). In addition, in Comparative Example 2, whether or not the coloring of each color in the display image can be completely eliminated depends on the maximum value of the luminance of the analog afterglow that can be generated.

[0150] However, in Comparative Example 2, as the analog afterglow signal is added to the image signal, the display device presents the display image that is different from the original to the user. In this way, the method of Comparative Example 2 of "adding an analog afterglow signal to the image signal in order to reduce the coloring in the display image" is feared to have a drawback from the viewpoint of the reproducibility of the image.

[0151] In view of this, the inventors of the present application (hereinafter, simply referred to as "the inventors") have had the idea of "preferably reducing the coloring in the display image by a method different from Comparative Example 2". The display device 1 is newly created by the inventors based on this idea.

[0152] Figure 10This 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).

[0153] 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 (the 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 (the transmittance of red light), i.e., g(R), is set to correspond to the changes in S210 and S211 over time as described above.

[0154] 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 10 In 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).

[0155] 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).

[0156] Figure 11 Graph G43 illustrates 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 described 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 described above. Thus, the tint in the displayed image is also reduced in display device 1.

[0157] 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 12the minimum value and the maximum value of the transmittance that can be achieved in the red display sub-pixel) in S431 cannot completely cancel out the influence of the maximum value of the red light luminance, even if it is the minimum value of the red light transmittance in the red display sub-pixel.

[0158] As described above, in the display device 1, the coloring in the displayed image is reduced by a method different from that of Comparative Example 2, "generating each color display sub-pixel data taking into account the different afterglow times of each color light". In this way, according to the display device 1, the display quality of a display device having a plurality of light emitting parts that respectively emit different colors can be improved by a method different from the past. Furthermore, as understood from the above G43, according to the display device 1, a display image closer to the original image can be presented to the user compared to Comparative Example 2. Therefore, from the viewpoint of the reproducibility of the image, it can be said that the display device 1 is more suitable than Comparative Example 2.

[0159] [Modified Example]

[0160] Figure 12 is a block diagram showing the configuration of the main part of a display device 1V that is a modified example of Embodiment 1. The display device 1V has a display pixel data generation section 13V instead of the display pixel data generation section 13. In addition, the control section of the display device 1V is referred to as a control section 10V (control device).

[0161] The display pixel data generation section 13V includes a second BL luminance filter operation section 134 and a BL luminance distribution calculation section 135 instead of the BL luminance distribution calculation section 131 and the BL luminance distribution filter operation section 132. The BL luminance distribution calculation section 135 has a first luminance distribution calculation section 136A and a second luminance distribution calculation section 136B.

[0162] The second BL luminance filter operation section 134 smoothes the corrected BL luminance data acquired from the BL luminance filter operation section 12 using a filter. In the second BL luminance filter operation section 134, as with the BL luminance distribution filter operation section 132 of Embodiment 1, τR= 10 ms and τ(G, B) = 0 ms are set.

[0163] The second BL brightness filter operation section 134 smoothes the corrected BL brightness data using τR, thereby generating red light corrected BL brightness data. The second BL brightness filter operation section 134 supplies the red light corrected BL brightness data to the first brightness distribution calculation section 136A. Then, the second BL brightness filter operation section 134 smoothes the corrected BL brightness data using τ(G, B), thereby generating green-blue light corrected BL brightness data. The second BL brightness filter operation section 134 supplies the green-blue light corrected BL brightness data to the second brightness distribution calculation section 136B.

[0164] The first brightness distribution calculation section 136A calculates f(R) from the red light corrected BL brightness data and the PSF. The first brightness distribution calculation section 136A supplies the calculated f(R) to the transmittance decision section 133. Similarly, the second brightness distribution calculation section 136B calculates f(G, B) from the green-blue light corrected BL brightness data and the PSF. The second brightness distribution calculation section 136B supplies the calculated f(G, B) to the transmittance decision section 133. The subsequent processing is the same as in Embodiment 1.

[0165] In Embodiment 1, f(W) is calculated from the corrected BL brightness data, and then f(W) is smoothed, thereby deriving f(R) and f(G, B). However, as in the display device IV, the smoothing processing can be performed before the brightness distribution is calculated, thereby deriving f(R) and f(G, B).

[0166] [Embodiment 2]

[0167] Figure 5 Fig. 2 is a diagram showing a configuration example of a BL brightness distribution filter operation section 132W of a display device 2 of Embodiment 2. Figure 13 Fig. 2 is a diagram showing a configuration example of a BL brightness distribution filter operation section 132W of a display device 2 of Embodiment 2. Figure 13 Fig. 2 is a diagram showing a configuration example of a BL brightness distribution filter operation section 132W of a display device 2 of Embodiment 2.

[0168] 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).

[0169] 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.

[0170] In embodiment 2, the correction circuit 1324 is as shown on the right side of the following equation (7) f(G, B)(n).

[0171] =TBL{f(W)(n-1), f(W)(n)}+f(W)(n)…(7),

[0172] 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.

[0173] 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 larger the value indicating the level, the larger the BL value.

[0174] exist Figure 14 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 14In the example of FIG. 10, TBL{f(W)(n-1), f(W)(n)} takes a positive value in a case where the BL value of the current frame is more than 5 levels greater than the BL value of the previous frame (but except for a case where the BL value of the current frame is level 10). On the other hand, TBL{f(W)(n-1), f(W)(n)} takes a negative value in a case where the BL value of the current frame is more than 5 levels less than the BL value of the previous frame (but except for a case where the BL value of the current frame is level 0). In this way, 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).

[0175] As described above, the BL luminance distribution filter operation section 132W can correct f(W)(n) according to the degree of divergence of f(W)(n) and f(W)(n-1), thereby calculating f(G, B). Further, as can be clear 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 filter operation section 132W can calculate f(G) and f(B) as long as it can calculate f(G) and f(B) by correcting f(W)(n).

[0176] (Effect of Embodiment 2)

[0177] Figure 14 FIG. 11 is a graph illustrating another example of the relationship of the BL luminance, the panel transmittance, and the display image luminance in the display device 1. Figure 14 The example of FIG. 10 is a reference example of Embodiment 2. Figure 14 The graph G51 of FIG. 10 illustrates an example of the time variation of the BL luminance in the reference example. In the example of FIG. 10, the BL luminance is set to the Low value at time t3. Figure 14 In the example of FIG. 10, at time t3, the green-blue light luminance rapidly decreases to the Low value. On the other hand, the red light luminance slowly decreases compared to the green-blue light luminance. Then, at time t3a, the red light luminance reaches the Low value (refer to the portion S510 of G51).

[0178] Figure 14 The graph G52 of FIG. 10 represents an example of the time variation of the panel transmittance in the reference example. As described above, in the display device 1, the red light transmittance after t3 is set in a manner to offset the effect of the slow decrease of the red light luminance shown in S510. In the example of FIG. 10, the red light transmittance rapidly decreases to the minimum value at t3. Figure 14 In the example of FIG. 10, at time t3, the green-blue light luminance rapidly decreases to the Low value. On the other hand, the red light luminance slowly decreases compared to the green-blue light luminance. Then, at time t3a, the red light luminance reaches the Low value (refer to the portion S510 of G51).

[0179] Figure 10The 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 15 In the example, it is also similar to the one mentioned above. Figure 15 Similarly, it is not possible to completely eliminate the red tinting in the displayed image.

[0180] Figure 15 This is a diagram illustrating the relationship between the BL brightness, panel transmittance, and displayed image brightness of display device 2. Figure 13 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 also 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).

[0181] 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 15 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 16 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).

[0182] ​ 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.

[0183] However, in the display device 2, it is desirable to pay attention to presenting a display image slightly different from the original to the user as the green-blue light transmittance is set as in S621. For example, which one of the display devices 1 or 2 (in other words, which one of the BL brightness distribution filter operation sections 132 or 132W) is appropriately selected by a designer of the display device in accordance with a display quality required by the display device.

[0184] [Embodiment 3]

[0185] ​ is a functional block diagram showing a configuration of a main part of the display device 3 of Embodiment 3. The display section of the display device 4 is referred to as a display section 30U. The display section 30U has a BL 31U instead of the BL 31. The BL 31U has one light emitting region (hereinafter, simply referred to as a single light emitting region) capable of controlling brightness. The single light emitting region includes one light source (not shown), for example. As an example, the single light emitting region includes one light emitting element 310. The BL 31U is different from the BL 31 in that the BL 31U does not have an LD function. Thus, the BL 31U can be referred to as a non-LD type BL. Alternatively, the BL 31U can be referred to as a 0-dimensional dimming type BL. In this way, in the BL related to one embodiment of the present disclosure, I2=1 and J2=1 can also be satisfied.

[0186] In Embodiment 3, the BL brightness calculation section 11 generates BL brightness data for the non-LD type BL based on the image signal. As a specific example, the BL brightness calculation section 11 generates BL brightness data indicating brightness of the one light emitting element 310 in each frame period, that is, brightness of LS(1, 1). The subsequent processing is the same as that of Embodiment 1. As described above, the light emission control method of one embodiment of the present disclosure can also be applied to the non-LD type BL. According to Embodiment 3, the same effects as those of Embodiment 1 can also be obtained.

[0187] As described above, the BL related to one embodiment of the present disclosure can have at least one light emitting region irradiating a plurality of display pixels. Furthermore, the at least one light emitting region can have at least one light emitting element as a light source.

[0188] [Supplement]

[0189] In each of the above-described embodiments, a display pixel 350 having a first display sub-pixel, a second display sub-pixel, and a third display sub-pixel is exemplified. However, the display pixel related to one embodiment of the present disclosure can have only a first display sub-pixel and a second display sub-pixel.

[0190] Therefore, one embodiment of the present disclosure relates to a light-emitting element that includes at least a first light-emitting component and a second light-emitting component. As an example, the light-emitting element (i) includes an excitation light source (e.g., the blue light source 370) that emits second light (e.g., blue light) as excitation light as the second light-emitting component, and (ii) includes a phosphor component (e.g., a yellow phosphor component) that receives the second light to emit first light (e.g., yellow light) as fluorescent light as the first light-emitting component. In this case, the light-emitting element can emit white light as mixed light.

[0191] According to the above, one embodiment of the present disclosure relates to a display pixel data generation portion (i) that can generate first display subpixel data (e.g., blue display subpixel data) using a first time constant, and (ii) that can generate second display subpixel data (e.g., yellow display subpixel data) using a second time constant different from the first time constant.

[0192] In the above embodiments, an example in which a light-emitting element that emits light from a QD layer EL is used as an excitation light source is described. However, another light-emitting element such as an LED or an organic EL light-emitting element can be used as the excitation light source. In the above embodiments, an example in which a QD phosphor particle is used as a phosphor component is described. However, another phosphor component can be used.

[0193] 〔Example of implementation by software〕

[0194] The control modules (particularly, the control portions 10 to 10W) of the display devices 1 to 4 can be implemented by logic circuits (hardware) formed in integrated circuits (IC chips) or the like, or can be implemented by software.

[0195] In the latter case, the display devices 1 to 4 have a computer that executes a command of a program that realizes each function. The computer includes, for example, at least one processor (control device) and at least one storage medium that stores the program and is readable by the computer. The computer realizes the object of one aspect of the present disclosure by reading the program from the storage medium by the processor and executing the program. As the processor, a CPU (Central Processing Unit) can be used, for example. As the storage medium, a "non-transitory tangible medium" such as a ROM (Read Only Memory) or the like can be used, and a magnetic tape, a magnetic disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, a RAM (Random Access Memory) or the like that expands the program can be further provided. In addition, the program can be supplied to the computer via any transmission medium (communication network, broadcast wave, or the like) that can transmit the program. In addition, one aspect of the present disclosure can be realized in the form of a data signal in which the program is embodied by electronic transmission and embedded in a carrier wave.

[0196] [ADDITIONAL DESCRIPTION]

[0197] One aspect of the present disclosure is not limited to the above-described embodiments, and various changes can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the respective embodiments are also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in the respective embodiments.

[0198] LEGEND

[0199] 1, 1V, 2, 3 display device

[0200] 10, 10V, 10W control unit (control device)

[0201] 11 BL brightness calculation unit (backlight brightness calculation unit)

[0202] 12 BL brightness filter operation unit

[0203] 13, 13V, 13W display pixel data generation unit

[0204] 30, 30U display unit

[0205] 31, 31U BL (backlight)

[0206] 35 display panel

[0207] 131, 135 BL brightness distribution calculation unit

[0208] 132, 132W BL brightness distribution filter operation section

[0209] 133 transmittance determination section

[0210] 136A first brightness distribution calculation section

[0211] 136B second brightness distribution calculation section

[0212] 305 light emitting region

[0213] 310 light emitting element

[0214] 320 excitation light source

[0215] 325 blue QD layer

[0216] 330 phosphor member

[0217] 331R red phosphor member (first light emitting member, first phosphor member)

[0218] 340 CF member

[0219] 350 display pixel

[0220] 360 green light source (second light emitting member)

[0221] 370 blue light source (third light emitting member)

[0222] 425 green QD layer

[0223] f(W) white light BL brightness distribution (mixed light backlight brightness distribution)

[0224] f(R) red light BL brightness distribution (first light backlight brightness distribution)

[0225] f(G, B) green / blue light BL brightness distribution (second light backlight brightness distribution, third light backlight brightness distribution)

[0226] LR red light (fluorescence, first light)

[0227] LG, LG1, LG2 green light (excitation light, second light)

[0228] LB blue light (excitation light, third light)

[0229] RSUB red display sub-pixel (first display sub-pixel)

[0230] GSUB green display sub-pixel (second display sub-pixel)

[0231] BSUB Blue display sub-pixel (third display sub-pixel).

Claims

1. A control device, comprising a control display device, characterized in that, The display device includes: A display panel having a display area with multiple display pixels arranged therein, and displaying images based on image signals; and A backlight having at least one light-emitting area that illuminates the plurality of display pixels based on the image signal. The at least one light-emitting region has at least one light-emitting element as a light source. Each of the plurality of display pixels has: a first display sub-pixel displaying a first color; a second display sub-pixel displaying a second color different from the first color; and a third display sub-pixel displaying a third color different from both the first color and the second color. Each of the at least one light-emitting element has: The first light-emitting component emits light of the first color, i.e., the first light; A second light-emitting component emits a second light, the second light being of the second color and having a shorter peak wavelength than the first light; and The third light-emitting component emits a third light, which is the third color light and has a shorter peak wavelength than the second light. The second light-emitting component is the light source that emits the second light. The third light-emitting component is the light source that emits the third light. The first light-emitting component is a first phosphor component that receives the second light and / or is excited by the third light, and emits the first light as fluorescence. 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: The backlight brightness calculation unit generates backlight brightness data based on the image signal; and The display pixel data generation unit generates display pixel data based on the backlight brightness data and the image signal. The display pixel data includes: 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 unit generates the first display sub-pixel data using a first time constant, generates the second display sub-pixel data using a second time constant different from the first time constant, and generates 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 in that, The first time constant is greater than the second time constant and the third time constant.

3. The control device according to claim 2, characterized in that, The second time constant is equal to the third time constant.

4. The control device according to claim 3, characterized in that, The second time constant and the third time constant are both 0.

5. The control device according to any one of claims 1 to 4, characterized in that, The display pixel data generation unit sets at least one of the first time constant, the second time constant, and the third time constant according to the frame rate of the image.

6. The control device according to any one of claims 1 to 5, characterized in that, The display pixel data generation unit calculates the mixed light backlight brightness distribution based on the backlight brightness data. The mixed light backlight brightness distribution is the brightness distribution of the mixed light illuminating each of the plurality of display pixels from the backlight source. The display pixel data generation unit smooths the mixed light backlight brightness distribution by using the first time constant and calculates the first light backlight brightness distribution, which is the brightness distribution of the first light illuminating each of the plurality of display pixels from the backlight source. The display pixel data generation unit smooths the mixed light backlight brightness distribution by using the second time constant and calculates the second light backlight brightness distribution, which is the brightness distribution of the second light illuminating each of the plurality of display pixels from the backlight. The display pixel data generation unit smooths the mixed light backlight brightness distribution by using the third time constant and calculates the third light backlight brightness distribution, which is the brightness distribution of the third light illuminating each of the plurality of display pixels from the backlight. The display pixel data is generated based on the first backlight brightness distribution, the second backlight brightness distribution, the third backlight brightness distribution, and the image signal.

7. The control device according to claim 6, characterized in that, The display pixel data generation unit generates the first display sub-pixel data based on the first backlight brightness distribution and the brightness value of the first color in the image; The display pixel data generation unit generates the second display sub-pixel data based on the second backlight brightness distribution and the brightness value of the second color in the image; The display pixel data generation unit generates the third display sub-pixel data based on the third backlight brightness distribution and the brightness value of the third color in the image.

8. The control device according to claim 6 or 7, characterized in that, The second backlight brightness distribution and the third backlight brightness distribution are the same.

9. The control device according to any one of claims 6 to 8, characterized in that, n is any integer. The display pixel data generation unit corrects the mixed backlight brightness distribution in the nth frame based on the degree of deviation between the mixed backlight brightness distribution in the nth frame and the mixed backlight brightness distribution in the (n-1)th frame of the image. And calculate the brightness distribution of the second backlight and the brightness distribution of the third backlight in the nth frame.

10. A display device, characterized in that, include: The control device according to any one of claims 1 to 9; The display panel; and The backlight.

Images