JP2015108795A - Display device, electronic apparatus, and driving method of display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device allowing reduction in a calculation quantity when controlling brightness of each of light sources of a sidelight light source independently, and an electronic apparatus and a display device driving method.SOLUTION: A display device comprises: an image display panel; a planar light source that includes a light guide plate for illuminating the image display panel from the back face, and a sidelight light source composed by arranging a plurality of light sources on a position opposite an incidence plane as at least one side face of the light guide plate; and a control section that controls the brightness of each of the light sources independently. The control section stores, for each light source as a lookup table, information of a light intensity distribution obtained when a flat surface of the image display panel is irradiated with incident light emitted from the light source through the light guide plate, and controls a light source lighting quantity of each light source on the basis of input signal information of the image and each lookup table.

Description

  The present invention relates to a display device, an electronic apparatus, and a display device driving method.

  In recent years, the demand for display devices for mobile devices such as mobile phones and electronic paper has increased. In a display device, one pixel includes a plurality of sub-pixels, each of the plurality of sub-pixels outputs light of a different color, and the display of the sub-pixel is switched on and off, so that one pixel can perform various operations. The color is displayed. Such display devices have improved display characteristics such as resolution and luminance year by year. However, since the aperture ratio decreases as the resolution increases, there is a problem that, when trying to achieve high luminance, it is necessary to increase the luminance of the backlight, and the power consumption of the backlight increases. In order to improve this, there is a technique of adding a white pixel as a fourth subpixel to a conventional red, green, and blue subpixel (for example, Patent Document 1). This technology reduces the current value of the backlight and the power consumption by the amount that the white pixel improves the luminance.

  In Patent Document 2, a liquid crystal display panel in which a plurality of fluorescent tubes are arranged on the back surface of the liquid crystal display panel is used, and after rewriting each pixel row of the liquid crystal display panel, the pixels are rewritten after a predetermined time has elapsed. A technique for preventing the occurrence of moving image blur by lighting and displaying the fluorescent tubes located in a row is described.

JP 2010-33014 A JP 2000-321993 A

  When the technique of Patent Document 2 is applied to a sidelight light source in which a plurality of light sources are arranged at a position facing at least one side surface of the light guide plate as an incident surface, the luminance distribution of the backlight becomes complicated. Since it changes, the amount of calculation increases.

  An object of the present aspect is to provide a display device, an electronic apparatus, and a display device driving method capable of reducing the amount of calculation in controlling the brightness independently for each light source of the sidelight light source.

  The display device according to this aspect includes an image display panel, a light guide plate that illuminates the image display panel from the back, and at least one side surface of the light guide plate as an incident surface, and a plurality of light sources at positions facing the incident surface. A planar light source comprising: an arrayed sidelight light source; and a control unit that controls brightness independently for each light source, wherein the control unit receives incident light from the light source through the light guide plate. The information of the light intensity distribution irradiated to the plane of the image display panel via the light source is stored as a look-up table for each light source, and each light source is based on the information of the input signal of the image and each look-up table. Control the amount of light source lighting.

  The electronic apparatus according to this aspect includes the display device according to this aspect described above.

  The display device driving method according to this aspect includes a plurality of image display panels, a light guide plate that illuminates the image display panel from the back, and at least one side surface of the light guide plate as an incident surface, at a position facing the incident surface. A planar light source comprising: a sidelight light source in which light sources are arranged; and a display device driving method comprising: an input signal detection step for detecting an input signal of an image; and an image analysis step for analyzing the image And a result of the analysis of the image, and a lookup for each light source storing information on a light intensity distribution in which incident light incident from the light source is irradiated onto the plane of the image display panel via the light guide plate A light source lighting amount calculation step of calculating a light source lighting amount of the light source from a table.

  According to this aspect, it is possible to provide a display device, an electronic apparatus, and a display device driving method capable of reducing the amount of calculation in controlling the brightness independently for each light source of the sidelight light source.

FIG. 1 is a block diagram illustrating an example of a configuration of a display device according to the present embodiment. FIG. 2 is a diagram showing a pixel array of the image display panel according to the present embodiment. FIG. 3 is an explanatory diagram of the light guide plate and the sidelight light source according to the present embodiment. FIG. 4 is an explanatory diagram illustrating an example of an intensity distribution of light acting by one light source of the sidelight light source according to the present embodiment. FIG. 5 is an explanatory diagram for explaining an example of the intensity distribution of light acted by one light source of the sidelight light source according to the present embodiment. FIG. 6 is a conceptual diagram of a reproduction HSV color space that can be reproduced by the display device of the present embodiment. FIG. 7 is a conceptual diagram showing the relationship between the hue and saturation of the reproduction HSV color space. FIG. 8 is a block diagram for explaining the signal processing unit according to the present embodiment. FIG. 9 is a flowchart of the driving method of the display device according to the present embodiment. FIG. 10 is a schematic diagram for explaining information of light intensity distribution in which incident light incident from a specific light source is irradiated from the light guide plate onto the plane of the image display panel. FIG. 11 is a schematic diagram for explaining a lookup table. FIG. 12 is an explanatory diagram for explaining the calculation of linear interpolation. FIG. 13 is an explanatory diagram for explaining the calculation of polynomial interpolation. FIG. 14 is an explanatory diagram for explaining a misalignment between the image display panel and the light source. FIG. 15 is an explanatory diagram for describing a modification of the sidelight light source according to the present embodiment. FIG. 16 is a diagram illustrating an example of an electronic apparatus to which the display device according to this embodiment is applied. FIG. 17 is a diagram illustrating an example of an electronic apparatus to which the display device according to this embodiment is applied. FIG. 18 is a diagram illustrating an example of an electronic apparatus to which the display device according to this embodiment is applied. FIG. 19 is a diagram illustrating an example of an electronic apparatus to which the display device according to this embodiment is applied. FIG. 20 is a diagram illustrating an example of an electronic apparatus to which the display device according to this embodiment is applied. FIG. 21 is a diagram illustrating an example of an electronic apparatus to which the display device according to this embodiment is applied. FIG. 22 is a diagram illustrating an example of an electronic apparatus to which the display device according to this embodiment is applied. FIG. 23 is a diagram illustrating an example of an electronic apparatus to which the display device according to this embodiment is applied. FIG. 24 is a diagram illustrating an example of an electronic apparatus to which the display device according to this embodiment is applied.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined.

(Configuration of display device)
FIG. 1 is a block diagram illustrating an example of a configuration of a display device according to the present embodiment. FIG. 2 is a diagram showing a pixel array of the image display panel according to the present embodiment.

  As shown in FIG. 1, the display device 10 receives an image input signal SRGB from the image output unit 11, sends an output signal SRGBW to each unit of the display device 10, and a signal processing unit 20 that controls the operation, An image display panel (display unit) 30 that displays an image based on the output signal SRGBW output from the processing unit 20, an image display panel drive unit 40 that controls driving of the image display panel 30, and the image display panel 30 on the back side A planar light source device 50 that illuminates the surface light source, and a planar light source device controller 60 that controls the driving of the planar light source device 50. The display device 10 has the same configuration as the image display device assembly described in Japanese Patent Application Laid-Open No. 2011-154323 in Patent Literature, and various modifications described in Japanese Patent Application Laid-Open No. 2011-154323. Is applicable.

  The signal processing unit 20 is an arithmetic processing unit that controls operations of the image display panel 30 and the planar light source device 50. The signal processing unit 20 is connected to an image display panel driving unit 40 for driving the image display panel 30 and a planar light source device control unit 60 for driving the planar light source device 50. The signal processing unit 20 processes an input signal input from the outside to generate an output signal and a planar light source device control signal. That is, the signal processing unit 20 reproduces an input value (input signal) of the input HSV color space of the input signal in the first color, the second color, the third color, and the fourth color. It is generated by converting to a reproduction value (output signal) of the space, and the generated output signal is output to the image display panel 30. The signal processing unit 20 outputs the generated output signal to the image display panel driving unit 40 and outputs the generated planar light source device control signal to the planar light source device control unit 60.

As shown in FIG. 1, the image display panel 30 has pixels 48 arranged in P ₀ × Q ₀ (P _{0 in} the row direction and Q _{0 in} the column direction) in a two-dimensional matrix (matrix). Has been. The example shown in FIG. 1 shows an example in which a plurality of pixels 48 are arranged in a matrix in an XY two-dimensional coordinate system. In this example, the row direction is the X direction and the column direction is the Y direction.

  The pixel 48 includes a first sub pixel 49R, a second sub pixel 49G, a third sub pixel 49B, and a fourth sub pixel 49W. The first sub-pixel 49R displays a first primary color (for example, red). The second subpixel 49G displays a second primary color (for example, green). The third subpixel 49B displays a third primary color (for example, blue). The fourth subpixel 49W displays a fourth color (specifically, white). As described above, the pixels 48 arranged in a matrix on the image display panel 30 include the first sub-pixel 49R that displays the first color, the second sub-pixel 49G that displays the second color, and the third color. It includes a third sub-pixel 49B for displaying and a fourth sub-pixel 49W for displaying a fourth color. The first color, the second color, the third color, and the fourth color are not limited to the first primary color, the second primary color, the third primary color, and the white color, and may be different colors such as complementary colors. The fourth sub-pixel 49W that displays the fourth color, when irradiated with the same light source lighting amount, the first sub-pixel 49R that displays the first color, the second sub-pixel 49G that displays the second color, It is preferable to be brighter than the third sub-pixel 49B that displays the third color. Hereinafter, the first sub-pixel 49R, the second sub-pixel 49G, the third sub-pixel 49B, and the fourth sub-pixel 49W are referred to as sub-pixels 49 when it is not necessary to distinguish them from each other.

  More specifically, the display device 10 is a transmissive color liquid crystal display device. As shown in FIG. 2, the image display panel 30 is a color liquid crystal display panel, and a first color filter that passes the first primary color is disposed between the first sub-pixel 49R and the image observer, and the second sub-pixel is arranged. A second color filter that passes the second primary color is arranged between the pixel 49G and the image observer, and a third color filter that passes the third primary color is arranged between the third sub-pixel 49B and the image observer. ing. In the image display panel 30, no color filter is disposed between the fourth sub-pixel 49W and the image observer. The fourth subpixel 49W may be provided with a transparent resin layer instead of the color filter. As described above, by providing the transparent resin layer, the image display panel 30 can suppress the occurrence of a large step in the fourth subpixel 49W by not providing the color filter in the fourth subpixel 49W.

  The image display panel drive unit 40 shown in FIGS. 1 and 2 is included in the control unit of the present embodiment, and includes a signal output circuit 41 and a scanning circuit 42. The image display panel driving unit 40 holds the video signal by the signal output circuit 41 and sequentially outputs it to the image display panel 30. The signal output circuit 41 is electrically connected to the image display panel 30 through a signal line DTL. The image display panel drive unit 40 selects a sub-pixel 49 in the image display panel 30 by the scanning circuit 42 and controls a switching element (for example, a thin film transistor (TFT; Thin) for controlling the operation (light transmittance) of the sub-pixel 49. Film transistor)) is controlled on and off. The scanning circuit 42 is electrically connected to the image display panel 30 by the scanning line SCL.

  The planar light source device 50 is disposed on the back surface of the image display panel 30 and illuminates the image display panel 30 by irradiating light toward the image display panel 30. FIG. 3 is an explanatory diagram of the light guide plate and the sidelight light source according to the present embodiment. The planar light source device 50 includes a light guide plate 54 and a plurality of light sources 56A, 56B, 56C, 56D, 56E, and 56F at positions facing the entrance surface E with at least one side surface of the light guide plate 54 as an entrance surface E. And arranged sidelight light sources 52. The plurality of light sources 56A, 56B, 56C, 56D, 56E, and 56F are, for example, light emitting diodes (LEDs) of the same color (for example, white). The plurality of light sources 56A, 56B, 56C, 56D, 56E, and 56F are arranged along one side surface of the light guide plate 54, and the light source arrangement direction in which the light sources 56A, 56B, 56C, 56D, 56E, and 56F are arranged is LY. In this case, incident light from the light sources 56A, 56B, 56C, 56D, 56E, and 56F enters the light guide plate 54 from the incident surface E in the light incident direction LX orthogonal to the light source arrangement direction LY. The center line of the light guide plate 54 in the light source arrangement direction LY is LYc.

  The planar light source device controller 60 controls the amount of light output from the planar light source device 50. The planar light source device controller 60 is included in the controller of this embodiment. Specifically, the planar light source device control unit 60 adjusts the current or duty ratio (duty ratio) supplied to the planar light source device 50 based on the planar light source device control signal SBL output from the signal processing unit 20. As a result, the amount of light (light intensity) irradiating the image display panel 30 is controlled. Then, the planar light source device controller 60 controls the current or the duty ratio (duty ratio) independently for each of the plurality of light sources 56A, 56B, 56C, 56D, 56E and 56F shown in FIG. It is possible to perform split drive control of the light source that controls the amount of light (light intensity) emitted by the light sources 56A, 56B, 56C, 56D, 56E, and 56F.

  FIG. 4 and FIG. 5 are explanatory diagrams for explaining an example of the intensity distribution of light acted on by one light source of the sidelight light source according to the present embodiment. FIG. 4 shows information on light intensity distribution in which incident light incident from the light source 56A is irradiated from the light guide plate 54 onto the plane of the image display panel 30 when only the light source 56A shown in FIG. When the incident light of the light source 56A enters the light guide plate 54 from the incident surface E in the light incident direction LX orthogonal to the light source arrangement direction LY, the light guide plate 54 moves to the illumination direction LZ that illuminates the image display panel 30 from the back. Irradiate. In the present embodiment, the illumination direction LZ is orthogonal to the light source arrangement direction LY and the light incident direction LX.

  FIG. 5 shows light intensity distribution information in which incident light incident from the light source 56C is irradiated from the light guide plate 54 onto the plane of the image display panel 30 when only the light source 56C shown in FIG. When the incident light of the light source 56C enters the light guide plate 54 from the incident surface E in the light incident direction LX orthogonal to the light source arrangement direction LY, the light guide plate 54 moves to the illumination direction LZ that illuminates the image display panel 30 from the back. Irradiate.

  Since the light guide plate 54 reflects light at both end faces appearing in the light source arrangement direction LY, the light intensity distribution of the light source 56A and the light source 56F that is close to both end faces appearing in the light source arrangement direction LY, the light source 56A, and the light source For example, the intensity distribution of the light emitted between the light sources 56C disposed between the light sources 56F is different. For this reason, as will be described later, the planar light source device controller 60 according to the present embodiment independently supplies current or current independently to the light sources 56A, 56B, 56C, 56D, 56E, and 56F shown in FIG. It is necessary to control the duty ratio (duty ratio) and to control the amount of light (light intensity) to be irradiated according to the light intensity distribution of each of the light sources 56A, 56B, 56C, 56D, 56E, and 56F. Next, processing operations executed by the display device 10, more specifically, the signal processing unit 20, will be described.

(Processing of display device)
FIG. 6 is a conceptual diagram of a reproduction HSV color space that can be reproduced by the display device of the present embodiment. FIG. 7 is a conceptual diagram showing the relationship between the hue and saturation of the reproduction HSV color space. FIG. 8 is a block diagram for explaining the signal processing unit according to the present embodiment. As shown in FIG. 1, the signal processing unit 20 receives an input signal SRGB that is image information to be displayed from an external image output unit 11. FIG. 9 is a flowchart of the driving method of the display device according to the present embodiment. The input signal SRGB includes information of an image (color) displayed at the position for each pixel as an input signal. Specifically, in the image display panel 30 in which P ₀ × Q ₀ pixels 48 are arranged in a matrix, the (p, q) -th pixel 48 (where 1 ≦ p ≦ P ₀ , 1 ≦ q ≦ Q ₀ ), the input signal of the first subpixel 49R whose signal value is x _{1− (p, q)} , the input signal of the second subpixel 49G whose signal value is x _{2− (p, q)} , and A signal including an input signal (see FIG. 1 ₎ of the third subpixel 49B having a signal value of x _{3- (p, q)} is input to the signal processing unit 20. As shown in FIG. 8, the signal processing unit 20 includes a timing generation unit 21, an image processing unit 22, an image analysis unit 23, a light source driving value calculation unit 24, a light source data storage unit 25, and a light source driving value determination. Part 26.

The signal processing unit 20 shown in FIGS. 1 and 8 detects the input signal SRGB as shown in FIG. 9 (step S11). Then, the timing generation unit 21 processes the input signal SRGB to drive the synchronization signal STM for synchronizing the timings of the image display panel drive unit 40 and the planar light source device control unit 60 for each frame to the image display panel drive. To the unit 40 and the planar light source device controller 60. The image processing unit 22 of the signal processing unit 20 processes the input signal SRGB to thereby determine the output signal of the first subpixel (signal value X _{1- (p, q)} ), the output signal of the second subpixel (signal value _{X2- (p, q)} ) for determining the display gradation of the second subpixel 49G, and the display gradation of the third subpixel 49B. Output signal (signal value X _{3- (p, q)} ) for the fourth sub-pixel and signal output from the fourth sub-pixel for determining the display gradation of the fourth sub-pixel 49W (signal value X _{4- ( p, q)} ) is generated, and the display data calculation step (step S16) to be output to the image display panel drive unit 40 is processed. Hereinafter, the calculation step (step S16) of the display data according to the present embodiment will be described in detail.

  The display device 10 includes the fourth sub-pixel 49W that outputs the fourth color (white) to the pixel 48, thereby providing a dynamic range of brightness in the HSV color space (reproduction HSV color space) as shown in FIG. Can be spread. That is, as shown in FIG. 6, the maximum value of the brightness V increases as the saturation S increases in the cylindrical HSV color space that can be displayed by the first subpixel 49R, the second subpixel 49G, and the third subpixel 49B. It becomes a shape on which a solid body having a substantially trapezoidal shape with a low value is placed.

  The image processing unit 22 of the signal processing unit 20 adds the fourth color (white), so that the maximum value Vmax (S) of the brightness with the saturation S in the expanded HSV color space as a variable is the signal processing unit. 20 is stored. That is, the signal processing unit 20 stores the value of the maximum brightness value Vmax (S) for each coordinate (value) of the saturation S and the hue H with respect to the three-dimensional shape of the HSV color space shown in FIG. Since the input signal includes the input signals of the first sub-pixel 49R, the second sub-pixel 49G, and the third sub-pixel 49B, the HSV color space of the input signal has a cylindrical shape, that is, a cylindrical portion of the reproduction HSV color space. It becomes the same shape.

Next, the image processing unit 22 of the signal processing unit 20 outputs the output of the first sub-pixel 49R based on at least the input signal (signal value x _{1-(p, q)} ) of the first sub-pixel 49R and the expansion coefficient α. A signal (signal value X _{1- (p, q)} ) is calculated and output to the first sub-pixel 49R. Further, the signal processing unit 20 outputs an output signal (signal value X ₂₋ ) of the second sub-pixel 49G based on at least the input signal (signal value x _{2− (p, q)} ) and the expansion coefficient α of the second sub-pixel 49G. _{(P, q)} ) is calculated and output to the second sub-pixel 49G. The signal processing unit 20 has at least an input signal (signal value _{x 3- (p, q))} of the third sub-pixel 49B and the output signal of the third sub-pixel 49B based on the expansion coefficient alpha (signal value _{X 3- (P, q)} ) is calculated and output to the third sub-pixel 49B. Further, the signal processing unit 20, an input signal of the first sub-pixel 49R (signal value _{x 1- (p, q))} , the input signal of the second sub-pixel 49G (signal value _{x 2- (p, q))} and Based on the input signal (signal value x _{3-(p, q)} ) of the third sub-pixel 49B, the output signal (signal value X _{4- (p, q)} ) of the fourth sub-pixel 49W is calculated _, and the fourth sub-pixel is calculated. Output to the pixel 49W.

  Specifically, the image processing unit 22 of the signal processing unit 20 calculates the output signal of the first subpixel 49R based on the expansion coefficient α of the first subpixel 49R and the output signal of the fourth subpixel 49W, and Based on the expansion coefficient α of the second subpixel 49G and the output signal of the fourth subpixel 49W, the output signal of the second subpixel 49G is calculated, and the expansion coefficient α of the third subpixel 49B and the output signal of the fourth subpixel 49W Based on the above, the output signal of the third sub-pixel 49B is calculated.

That is, the signal processing unit 20 sets (p, q) -th pixel (or first sub-pixel 49R, second sub-pixel 49G, and third sub-pixel 49B as a set when χ is a constant depending on the display device. ), The signal value X _{1- (p, q)} that is the output signal of the first sub-pixel 49R, the signal value X _{2- (p, q)} that is the output signal of the second sub-pixel 49G, and the third sub-pixel 49B. The signal value X _{3- (p, q)} that is the output signal of is obtained from the following equations (1) to (3).

_{X1- (p, q)} = [alpha] .x1- _{(p, q)-[} chi] .X4- _{(p, q)} (1)

_{X2- (p, q)} = [alpha] .x2- _{(p, q)-[} chi] .X4- _{(p, q)} (2)

X _{3-(p, q)} = α · x _{3-(p, q)} -χ · X _{4-(p, q)} (3)

  The signal processing unit 20 obtains the maximum value Vmax (S) of the brightness with the saturation S in the HSV color space expanded by adding the fourth color as a variable, and the input signal of the sub-pixel 49 in the plurality of pixels 48. Based on the values, the saturation S and the lightness V (S) in the plurality of pixels 48 are obtained.

Saturation S and lightness V (S) are represented by S = (Max−Min) / Max and V (S) = Max. The saturation S can take a value from 0 to 1, and the lightness V (S) can take a value from 0 to (2 ⁿ −1). n is the number of display gradation bits. Further, Max is the maximum value among the input signal value of the first sub-pixel 49R, the input signal value of the second sub-pixel 49G, and the input signal value of the third sub-pixel 49B to the pixel 48. Min is the minimum value among the input signal value of the first sub-pixel 49R, the input signal value of the second sub-pixel 49G, and the input signal value of the third sub-pixel 49B to the pixel 48. Further, the hue H is represented by 0 ° to 360 ° as shown in FIG. From 0 ° to 360 °, the colors are red (Red), yellow (Yellow), green (Green), cyan (Cyan), blue (Blue), magenta (Magenta), and red.

In the present embodiment, the signal value X _{4− (p, q)} can be obtained based on the product of Min _{(p, q)} and the expansion coefficient α. Specifically, the signal value X _{4- (p, q)} can be obtained based on the following equation (4). In Expression (4), the product of Min _{(p, q)} and the expansion coefficient α is divided by χ, but the present invention is not limited to this. χ will be described later.

X _{4− (p, q)} = Min _{(p, q)} · α / χ (4)

Generally, in the (p, q) th pixel, the input signal of the first sub-pixel 49R (signal value _{x 1- (p, q))} , the input signal of the second sub-pixel 49G (signal value _{x 2-(p , Q)} ) and the input signal (signal value _{x3- (p, q)} ) of the third sub-pixel 49B, saturation S _{(p, q)} and brightness in the HSV color space of the cylinder V (S) _{(p, q)} can be obtained from the following equations (5) and (6).

S _{(p, q)} = (Max _{(p, q)} −Min _{(p, q)} ) / Max _{(p, q)} (5)

V (S) _{(p, q)} = Max _{(p, q)} (6)

Here, Max _{(p, q)} is an input signal value of three sub-pixels 49 of (x _{1- (p, q)} , x _{2- (p, q)} , x _{3- (p, q)} ). Min _{(p, q)} is the value of three subpixels 49 of (x _{1-(p, q)} , x _{2-(p, q)} , x _{3-(p, q)} ) This is the minimum value of the input signal value. In this embodiment, n = 8. That is, the number of display gradation bits is 8 bits (the display gradation value is 256 gradations from 0 to 255).

No color filter is arranged in the fourth sub-pixel 49W that displays white. The fourth sub-pixel 49W that displays the fourth color, when irradiated with the same light source lighting amount, the first sub-pixel 49R that displays the first color, the second sub-pixel 49G that displays the second color, Brighter than the third sub-pixel 49B that displays the third color. A signal having a value corresponding to the maximum signal value of the output signal of the first subpixel 49R is input to the first subpixel 49R, and the signal value corresponding to the maximum signal value of the output signal of the second subpixel 49G is input to the second subpixel 49G. When a signal having a value is input and a signal having a value corresponding to the maximum signal value of the output signal of the third subpixel 49B is input to the third subpixel 49B, the pixel 48 or the group of pixels 48 includes The luminance of the aggregate of the first sub-pixel 49R, the second sub-pixel 49G, and the third sub-pixel 49B is BN _1-3 . The luminance of the fourth subpixel 49W when a signal having a value corresponding to the maximum signal value of the output signal of the fourth subpixel 49W is input to the fourth subpixel 49W included in the pixel 48 or the group of pixels 48. Assume that BN ₄ is set. That is, the maximum luminance white is displayed by the aggregate of the first sub-pixel 49R, the second sub-pixel 49G, and the third sub-pixel 49B, and this white luminance is represented by BN _1-3 . Then, when χ is a constant depending on the display device, the constant χ is represented by χ = BN ₄ / BN _1-3 .

Specifically, a signal value x _{1− (p, q) is} input to the aggregate of the first subpixel 49R, the second subpixel 49G, and the third subpixel 49B as an input signal having the next display gradation value. = 255, relative to the signal value _{x 2- (p, q) =} 255, the white luminance _{BN 1-3} at the time when the signal value _{x 3- (p, q) =} 255 is input, the fourth subpixel 49W For example, the luminance BN ₄ when the input signal having the display gradation value 255 is input is 1.5 times. That is, in this embodiment, χ = 1.5.

By the way, when the signal value X _{4- (p, q)} is given by the above-described equation (4), Vmax (S) can be expressed by the following equations (7) and (8).

If S ≦ S ₀ ,
Vmax (S) = (χ + 1) · (2 ⁿ −1) (7)

If S ₀ <S ≦ 1:
Vmax (S) = (2 ⁿ −1) · (1 / S) (8)
Here, S ₀ = 1 / (χ + 1).

  The maximum value Vmax (S) of lightness obtained by adding the fourth color and using the saturation S in the HSV color space as a variable, for example, is given to the signal processing unit 20 as a kind of look. Stored as an uptable. Alternatively, the maximum value Vmax (S) of lightness with the saturation S in the enlarged HSV color space as a variable is obtained in the signal processing unit 20 each time.

Next, signal values X _{1- (p, q)} , X _{2- (p, q)} , X _{3- (p, q)} , X ₄₋ which are output signals at the (p, q) -th pixel 48. _A method for _{obtaining (p, q)} (extension processing) will be described. The next processing is the luminance of the first primary color displayed by (first subpixel 49R + fourth subpixel 49W), the luminance of the second primary color displayed by (second subpixel 49G + fourth subpixel 49W), ( This is performed so as to maintain the luminance ratio of the third primary color displayed by the third subpixel 49B + the fourth subpixel 49W). In addition, the color tone is maintained (maintained). Furthermore, the gradation-luminance characteristics (gamma characteristics, γ characteristics) are maintained (maintained). In addition, when all of the input signal values are zero or small in any one of the pixels 48 or the group of pixels 48, the expansion coefficient α may be obtained without including such a pixel 48 or the group of pixels 48. .

(First step)
First, the signal processing unit 20 obtains the saturation S and the lightness V (S) in the plurality of pixels 48 based on the input signal values of the sub-pixels 49 in the plurality of pixels 48. Specifically, a signal value x _{1− (p, q)} that is an input signal of the first subpixel 49R to the (p, q) th pixel 48, and a signal value that is an input signal of the second subpixel 49G. Based on x _{2- (p, q)} , signal value x _{3- (p, q)} that is an input signal of the third sub-pixel 49B, S _{(p, q)} , V from Formula (7) and Formula (8) (S) _{Find (p, q)} . The signal processing unit 20 performs this process for all the pixels 48.

(Second step)
Next, the signal processing unit 20 obtains the expansion coefficient α (S) based on Vmax (S) / V (S) obtained in the plurality of pixels 48.

  α (S) = Vmax (S) / V (S) (9)

(Third step)
Next, the signal processing unit 20 converts the signal value X _{4- (p, q)} in the (p, q) -th pixel 48 to at least the signal value x _{1- (p, q)} , the signal value x ₂₋ It is determined based on _{(p, q)} and the signal value x _{3- (p, q)} . In the present embodiment, the signal processing unit 20 determines the signal value X _{4− (p, q) based} on Min _{(p, q)} , the expansion coefficient α, and the constant χ. More specifically, as described above, the signal processing unit 20 obtains the signal value X _{4- (p, q) based} on the above equation (4). The signal processing unit 20 obtains a signal value X _{4− (p, q)} in all of the P ₀ × Q ₀ pixels 48.

(4th process)
Thereafter, the signal processing unit 20 converts the signal value X _{1- (p, q)} in the (p, q) -th pixel 48 to the signal value x _{1- (p, q)} , the expansion coefficient α, and the signal value X _{4. - (p, q)} obtained based on, the (p, q) th pixel 48 the signal value _X 2 in _{- (p, q)} and the signal value _{x 2 - (p, q)} , expansion coefficient α and the signal value X _{4- (p, q)} , and the signal value X _{3- (p, q)} at the (p, q) -th pixel 48 is converted to the signal value x _{3- (p, q)} , the expansion coefficient α, and _Obtained based on the signal value X _{4− (p, q)} . Specifically, the signal processing unit 20 outputs the signal value X _{1- (p, q)} , the signal value X _{2- (p, q),} and the signal value X _{3- ( p, q)} is obtained based on the above formulas (1) to (3).

The signal processing unit 20 expands the value of Min _{(p, q)} by the expansion coefficient α as shown in Expression (4). As described above, the value of Min _{(p, q)} is expanded by the expansion coefficient α, so that not only the luminance of the white display subpixel (fourth subpixel 49W) increases, but also the red color as shown in the above equation. The luminance of the display subpixel, the green display subpixel, and the blue display subpixel (corresponding to the first subpixel 49R, the second subpixel 49G, and the third subpixel 49B, respectively) also increases. For this reason, the problem that the dullness of color generate | occur | produces can be avoided. That is, as compared with the case where the value of Min _{(p, q)} is not expanded, the value of Min _{(p, q)} is expanded by the expansion coefficient α, so that the luminance of the entire image becomes α times. Therefore, for example, an image display such as a still image can be performed with high luminance, which is preferable.

  As shown in FIG. 9, the signal processing unit 20 processes the display data calculation step (step S16) and performs image analysis of the input signal SRGB (step S12).

The image analysis unit 23 outputs a signal value X _{1- (p, q)} , a signal value X _{2- (p, q)} , a signal value X _{3- (p, q)} in the (p, q) -th pixel 48 _, and It is analyzed that the signal value X _{4− (p, q)} is expanded α times. For this reason, the display device 10 sets the luminance of the planar light source device 50 to the expansion coefficient in order to obtain the same image luminance as that of the unexpanded image based on the information of the image input signal SRGB. What is necessary is just to reduce based on (alpha). Specifically, a plurality of light sources 56A, 56B, 56C, 56D, so that the light driving value calculation unit 24 and the light driving value determination unit 26 increase the luminance of the planar light source device 50 by (1 / α) times. The current or the duty ratio (duty ratio) may be controlled independently for 56E and 56F.

  FIG. 10 is a schematic diagram for explaining information of light intensity distribution in which incident light incident from a specific light source is irradiated from the light guide plate onto the plane of the image display panel. FIG. 11 is a schematic diagram for explaining a lookup table. The light source data storage unit 25 is a look-up table (LUT: data that stores representative values of light intensity for each of M arrays in the light source array direction LY and N arrays in the light incident direction LX. Lookup table). For example, as illustrated in FIG. 11, when only the light source 56 </ b> A illustrated in FIG. 3 is turned on, the incident light incident from the light source 56 </ b> A is irradiated from the light guide plate 54 onto the plane of the image display panel 30. The light intensity distribution information (see FIG. 4) is stored as a lookup table LUTA. Further, in the light source data storage unit 25, when only the light source 56B shown in FIG. 3 is turned on, the light intensity distribution information on the incident light incident from the light source 56B from the light guide plate 54 to the plane of the image display panel 30 is stored. It is stored as a lookup table LUTB. Further, in the light source data storage unit 25, when only the light source 56C shown in FIG. 3 is turned on, the light intensity distribution information on the incident light incident from the light source 56C from the light guide plate 54 to the plane of the image display panel 30 is stored. It is stored as a lookup table LUTC. Further, in the light source data storage unit 25, when only the light source 56D shown in FIG. 3 is turned on, information on the light intensity distribution in which the incident light incident from the light source 56D is irradiated from the light guide plate 54 onto the plane of the image display panel 30 is stored. It is stored as a lookup table LUTD. In the light source data storage unit 25, when only the light source 56E shown in FIG. 3 is turned on, the light intensity distribution information on the incident light incident from the light source 56E from the light guide plate 54 to the plane of the image display panel 30 is stored. It is stored as a lookup table LUTE. Further, in the light source data storage unit 25, when only the light source 56F shown in FIG. 3 is turned on, information on the light intensity distribution in which the incident light incident from the light source 56F is irradiated from the light guide plate 54 onto the plane of the image display panel 30 is stored. It is stored as a lookup table LUTF.

  The lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF in this embodiment correspond to each of the light sources 56A, 56B, 56C, 56D, 56E, and 56F. In the lookup table of this embodiment, among the light sources 56A, 56B, 56C, 56D, 56E, and 56F, for example, the set of the light sources 56A and 56B, the set of the light sources 56C and 56D, and the set of the light sources 56E and 56F are turned on simultaneously. A look-up table in the case of the above may be stored. As a result, labor for creating the lookup table can be saved, and the storage capacity of the light source data storage unit 25 can be reduced. As a result, the integrated circuit that stores the light source data storage unit 25 can be downsized.

  In the light guide plate 54, when the light sources 56A, 56B, 56C and the light sources 56F, 56E, 56D are arranged symmetrically with respect to the center line LYc in the light source arrangement direction LY, the lookup tables LUTA, LUTB, LUTC , LUTD, LUTE, and LUTF, the lookup tables LUTA, LUTB, and LUTC on one side of the center line LYc in the light source arrangement direction LY are generated and stored, and the lookup tables LUTD, LUTE, and LUTF on the other side are generated. Is axisymmetric with respect to the center line LYc and may be omitted.

  The light source drive value calculation unit 24 refers to the lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF in the light source data storage unit 25 so as to be close to the (1 / α) value analyzed by the image analysis unit 23. The look-up tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF are overlapped to calculate the light source lighting amounts of the light sources 56A, 56B, 56C, 56D, 56E, and 56F (step S13). For example, the representative luminance (1 ≦ i ≦ N, 1 ≦ j ≦ M) obtained by superimposing the (i, j) th look-up tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF is expressed by the following formula ( 10).

  Thereby, the light source drive value calculation unit 24 can reduce the amount of calculation by replacing complicated calculation processing with reference processing of simple lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF.

  As described above, in order for the image display panel drive unit 40 to display the image display panel 30, a luminance distribution in units of 48 pixels is required. Therefore, the light source drive value determination unit 26 is based on the light source lighting amounts of the light sources 56A, 56B, 56C, 56D, 56E, and 56F obtained in step S13, and the lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF. Then, the luminance distribution in units of 48 pixels is calculated (step S14). In the calculation processing of the luminance distribution of the pixel 48 unit, the luminance information of the pixel 48 unit is calculated by interpolation calculation. As a result, the amount of information for each pixel 48 unit is very large. However, in this embodiment, the lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF are created with the thinned representative values. The size of the lookup table can be reduced. Further, the light source driving value determination unit 26 can reduce the calculation load by performing linear interpolation calculation.

  In the luminance information for each pixel 48, the change in the light source arrangement direction LY is steep, and the change in the light incident direction LX is a gentle change. FIG. 12 is an explanatory diagram for explaining the calculation of linear interpolation. FIG. 13 is an explanatory diagram for explaining the calculation of polynomial interpolation. The luminance information in each pixel 48 in the light incident direction LX is subjected to the linear interpolation process shown in FIG. 12, and the luminance information in each pixel 48 in the light source arrangement direction LY is subjected to the polynomial interpolation process shown in FIG. Interpolation calculation. Polynomial interpolation is, for example, cubic interpolation. As a result, the lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF need only have at least M as the sum of the number of light sources and the number of light sources in the light source arrangement direction LY. Thereby, the size of the lookup table can be significantly reduced.

  As a control unit, the light source data storage unit 25 stores look-up tables LUTA, LUTB, and LUTC for the light sources 56A, 56B, and 56C on one side of the center line LYc in the light source arrangement direction LY. The light source drive value calculation unit 24 has a line-symmetric relationship with respect to the center line LYc as information on the light intensity distribution that the light sources 56D, 56E, and 56F on the other side of the center line LYc irradiate on the plane of the image display panel 30. Information on the look-up tables LUTC, LUTB, and LUTA of a certain light source 56C, 56B, and 56A is read out. Information on luminance in each pixel 48 of the image display panel 30 is stored (held) in a lookup table for one side of the center line LYc in the light source arrangement direction LY, and is symmetrical with respect to the center line LYc on the other side. By using the luminance information, the light source drive value determining unit 26 can significantly reduce the lookup table capacity.

Next, the light source driving value determination unit 26 sends the luminance information for each pixel 48 to the image processing unit 22, and the image processing unit 22 corrects the luminance based on the luminance information for each pixel 48, and The signal value X _{1- (p, q)} , signal value X _{2- (p, q)} , signal value X _{3- (p, q)} and signal value X _{4- (p, q)} A synchronization process for calculating the output signal SRGBW is performed so as to output _q) (step S15). Based on the synchronization signal STM, the image display panel driving unit 40 displays an image on the image display panel 30 for each frame, and the planar light source device control unit 60 uses the light sources 56A, 56B, and 56C of the planar light source device 50. , 56D, 56E and 56F are driven independently. As described above, the display device driving method includes the input signal detection step (S11) for detecting the input signal of the image, the image analysis step (S12) for analyzing the image, the result of the image analysis, and the light source. Light source lighting that calculates a light source lighting amount of a light source from a look-up table for each light source that stores information on a light intensity distribution in which incident light incident on the plane of the image display panel 30 is irradiated through the light guide plate 54 through the light guide plate 54 A quantity calculation step (S13). Thereby, it becomes possible to control so that the total amount of light source lighting of the light sources 56A, 56B, 56C, 56D, 56E, and 56F can be reduced, and the power consumption can be reduced.

  The display device 10 includes a planar light source device 50 that is a planar light source including the image display panel 30, a light guide plate 54, and a sidelight light source 52. As the control unit, the image display panel driving unit 40 and the planar light source device control unit 60 are synchronized in accordance with the calculation of the signal processing unit 20, and the information of the image input signal SRGB and the lookup tables LUTA, LUTB, and LUTC. The light source lighting amounts of the light sources 56A, 56B, 56C, 56D, 56E, and 56F are independently controlled based on the LUTD, LUTE, and LUTF. Thereby, it becomes possible to control so that the total amount of light source lighting of the light sources 56A, 56B, 56C, 56D, 56E, and 56F can be reduced, and the power consumption can be reduced.

(First modification)
FIG. 14 is an explanatory diagram for explaining a misalignment between the image display panel and the light source. In general, the display device 10 is a separate component from the light guide plate 54 and the light sources 56A, 56B, 56C, 56D, 56E, and 56F, and there is a possibility that misassembly occurs as a production variation. As the misalignment, the planar light source device 50 is in a state in which the light sources 56A, 56B, 56C, 56D, 56E, and 56F are mounted on the flexible substrate, and therefore the intervals between the light sources 56A, 56B, 56C, 56D, 56E, and 56F are as follows. In addition to being constant, there is a possibility that the positional relationship between the light guide plate 54 and the light sources 56A, 56B, 56C, 56D, 56E, and 56F is shifted together. Alternatively, since the planar light source device 50 and the image display panel 30 are separate components, there is a possibility that misalignment occurs in the mutual positional relationship.

  The display device 10 according to the present embodiment causes the light sources 56A, 56B, 56C, 56D, 56E, and 56F to emit light independently of each other, and the image information for each pixel 48 according to the luminance distribution of the planar light source device 50. Adjust to. For this reason, when the calculation result of the luminance distribution does not match the luminance distribution in the actual planar light source device 50, the image displayed on the image display panel 30 may be deteriorated in image quality.

  As shown in FIG. 14, the display device 10 according to the present embodiment measures a distance ΔT between a reference position CL ideally attached to the light guide plate 54 and an actual position LL of the light source 56C at the time of manufacture. If there is a deviation in the light source arrangement direction LY above the threshold value, in step S14 described above, correction is performed to shift the coordinates of the lookup table LUTR by ΔT. Thereby, the display apparatus 10 according to the first modification of the present embodiment can suppress image quality deterioration of the image due to the misalignment. The distance ΔT may be detected by a sensor built in the display device 10. Note that the lookup table LUTR is the same as the lookup table LUTC, but may be any one of the lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF.

(Second modification)
FIG. 15 is an explanatory diagram for describing a modification of the sidelight light source according to the present embodiment. The planar light source device 50 includes a light guide plate 54 and a plurality of light sources 56A, 56B at positions facing the entrance surface E1 and the entrance surface E2, with at least both side surfaces of the light guide plate 54 as the entrance surface E1 and the entrance surface E2. A first sidelight light source 52A in which 56C, 56D, 56E and 56F are arranged, and a second sidelight light source 52B in which a plurality of light sources 57A, 57B, 57C, 57D, 57E and 57F are arranged. The planar light source device control unit 60 independently supplies current or duty to the plurality of light sources 56A, 56B, 56C, 56D, 56E, 56F, 57A, 57B, 57C, 57D, 57E, and 57F shown in FIG. A light source that controls the ratio (duty ratio) and controls the amount of light (light intensity) emitted by each of the light sources 56A, 56B, 56C, 56D, 56E, 56F, 57A, 57B, 57C, 57D, 57E, and 57F. Can be divided and controlled.

  The planar light source device 50 according to the second modification of the present embodiment includes a first sidelight light source 52A and a second sidelight light source 52B. For this reason, in the light source data storage unit 25, only one of the light sources 56A, 56B, 56C, 56D, 56E, 56F, 57A, 57B, 57C, 57D, 57E, and 57F is turned on, and the light source that is turned on When the information on the light intensity distribution (see FIG. 4) in which the incident light incident from the light guide plate 54 is irradiated on the plane of the image display panel 30 is stored as a lookup table, the first incident surface E1 and the second incident surface E2 are stored. Therefore, the number of lookup tables increases. Therefore, the first sidelight light source 52A and the second sidelight light source 52B include a plurality of light sources 56A, 56B, 56C, 56D, 56E, and 56F, and a plurality of light sources 57A, 57B, 57C, 57D, 57E, and 57F. Are arranged symmetrically with respect to the center line LXc in the light incident direction LX. When only one of the light sources on the second incident surface E2 side is turned on, the information on the light intensity distribution of the lookup table in which the incident light incident from this light source is irradiated from the light guide plate 54 onto the plane of the image display panel 30 is This is the same as the information on the light intensity distribution of the look-up table of the light source on the first incident surface E1 side that is axisymmetric with respect to the center line LXc in the light incident direction LX of the lit light source. As described above, the lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF of this embodiment correspond to each of the light sources 56A, 56B, 56C, 56D, 56E, and 56F. If the light source data storage unit 25 stores the lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF, the light source drive value calculation unit 24 not only uses the first sidelight light source 52A but also the second sidelight light source. Also for 52B, the look-up tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF in the light source data storage unit 25 are referred to, so that the look is close to the (1 / α) value analyzed by the image analysis unit 23. The light source lighting amounts of the light sources 57A, 57B, 57C, 57D, 57E, and 57F can be calculated by superimposing the uptables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF.

  As described above, the planar light source device 50 includes the first sidelight light source 52A and the second sidelight light source 52B. As a control unit, the light source data storage unit 25 stores look-up tables LUTA, LUTB, and LUTC for the light sources 56A, 56B, and 56C on one side of the center line LYc in the light source arrangement direction LY. The light source drive value calculation unit 24 has a line-symmetric relationship with respect to the center line LYc as information on the light intensity distribution that the light sources 56D, 56E, and 56F on the other side of the center line LYc irradiate on the plane of the image display panel 30. Information on the look-up tables LUTC, LUTB, and LUTA of a certain light source 56C, 56B, and 56A is read out. In this manner, the light source data storage unit 25 stores the lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF on one side of the center line LXc in the light incident direction LX, and the lookup table on the other side. Since the line is symmetrical with respect to the center line LXc, it may be omitted. Then, the luminance information at each pixel 48 of the image display panel 30 is stored (held) in the look-up table for one side of the center line LXc in the light incident direction LX, and is lined with respect to the center line LXc for the other side. By using symmetrical luminance information, the light source drive value determination unit 26 can significantly reduce the lookup table capacity.

  The planar light source device 50 according to the second modification of the present embodiment can further reduce the look-up table. For example, on the light guide plate 54, the light sources 56A, 56B, and 56C and the light sources 56F, 56E, and 56D are arranged symmetrically with respect to the center line LYc in the light source arrangement direction LY. Similarly, on the light guide plate 54, light sources 57A, 56B, and 57C and light sources 57F, 57E, and 57D are arranged symmetrically with respect to the center line LYc in the light source arrangement direction LY. Therefore, the light source data storage unit 25 stores the lookup tables LUTA, LUTB, and LUTC.

  Since the light sources 56A, 56B, and 56C and the light sources 56F, 56E, and 56D are arranged in line symmetry with respect to the center line LYc in the light source arrangement direction LY, the light source drive value calculation unit 24 has the center in the light source arrangement direction LY. Lookup tables LUTA, LUTB, and LUTC are referred to for light sources 56A, 56B, and 56C on one side of line LYc, and light source arrays of lookup tables LUTA, LUTB, and LUTC are also used for light sources 56F, 56E, and 56D on the other side. Reference is made so as to be symmetrical with respect to the center line LYc in the direction LY.

  Further, the light source drive value calculation unit 24 refers to the lookup tables LUTA, LUTB, and LUTC of the light sources 56A, 56B, and 56C that are symmetrical with respect to the center line LXc in the light incident direction LX with respect to the light sources 57A, 57B, and 57C. Then, the light source driving value calculation unit 24 refers to the lookup table LUTA of the light source 56A that is point-symmetric with respect to the center point PR at which the center line LXc and the center line LYc intersect for the light source 57F. Further, the light source drive value calculation unit 24 refers to the lookup table LUTB of the light source 56B that is point-symmetric with respect to the center point PR for the light source 57E. In addition, the light source drive value calculation unit 24 refers to the lookup table LUTC of the light source 56C that is point-symmetric with respect to the center point PR for the light source 57D. As described above, the light source drive value calculation unit 24 is symmetric with respect to the light sources 57D, 57E, and 57F with respect to the center line LXc in the light incident direction LX and line symmetric with respect to the center line LYc in the light source arrangement direction LY (that is, symmetrical twice). The look-up tables LUTC, LUTB, and LUTA of the light sources 56C, 56B, and 56A are referred to.

  As described above, the planar light source device 50 includes the first sidelight light source 52A and the second sidelight light source 52B. As a control unit, the light source data storage unit 25 stores look-up tables LUTA, LUTB, and LUTC for the light sources 56A, 56B, and 56C on one side of the center line LYc in the light source arrangement direction LY. The light source drive value calculation unit 24 has a line-symmetric relationship with respect to the center line LYc as information on the light intensity distribution that the light sources 56D, 56E, and 56F on the other side of the center line LYc irradiate on the plane of the image display panel 30. Information on the look-up tables LUTC, LUTB, and LUTA of a certain light source 56C, 56B, and 56A is read out. In addition, the light source drive value calculation unit 24 uses the center as information on the light intensity distribution that the light sources 57A, 57B, and 57C on one side of the center line LYc of the second sidelight light source 52B irradiate on the plane of the image display panel 30. Information on the lookup tables LUTA, LUTB, and LUTC of the light sources 56A, 56B, and 56C that are in a line-symmetrical relationship with respect to the line LXc is read. Further, the light source drive value calculation unit 24 uses the center as information on the light intensity distribution that the light sources 57D, 57E, and 57F on the other side of the center line LYc of the second sidelight light source 52B irradiate on the plane of the image display panel 30. Information on the look-up tables LUTC, LUTB, and LUTA of the light sources 56C, 56B, and 56A that are in a point-symmetric relationship with respect to the center point PR where the line LXc and the center line LYc intersect is read out. The information on the luminance of each pixel 48 of the image display panel 30 that has been read and stored is superimposed and approximated to the (1 / α) value analyzed by the image analysis unit 23, so that the light sources 56A, 56B, and 56C. 56D, 56E, 56F, 57A, 57B, 57C, 57D, 57E and 57F. Thereby, the light source drive value calculation unit 24 can reduce the amount of calculation by replacing complicated calculation processing with reference processing of simple lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF. And the lookup table capacity to be stored in advance is greatly reduced.

  In the image display panel 30 and the planar light source device 50 (light guide plate 54) described above, the case where the light incident direction LX is longer than the light source array direction LY has been described, but the present invention is not limited to this, and the light source array direction LY is incident. It may be longer than the direction LX or the same length.

  As another example, the planar light source device 50 includes a first sidelight light source 52A and a second sidelight light source 52B, and irradiates the plane of the image display panel 30 of another light source with only the lookup table LUTA. It may be used as information on the light intensity distribution. The light sources 56 </ b> A, 56 </ b> F, 57 </ b> A, 57 </ b> F at the ends of the light guide plate 54 in the light source arrangement direction LY are easily affected by members around the light guide plate 54. For this reason, the light sources 56B, 56C, 56D, 56E, 57B, 57C, 57D, and 57E store and read the same common look-up table, and the light sources at the ends of the light guide plate 54 in the light source arrangement direction LY 56A, 56F, 57A, and 57F process as follows.

  The light source data storage unit 25 as a control unit stores a lookup table LUTA for the light source 56A located on one side of the center line LYc in the light source arrangement direction LY. The light source drive value calculation unit 24 uses the light source 56A having a line symmetry with respect to the center line LYc as information on the light intensity distribution that the light source 56F on the other side of the center line LYc irradiates the plane of the image display panel 30. Read the information of the lookup table LUTA. In addition, the light source driving value calculation unit 24 uses the light source 57A on one side of the center line LYc of the second sidelight light source 52B as information on the light intensity distribution applied to the plane of the image display panel 30 with respect to the center line LXc. The information of the look-up table LUTA of the light source 56A having a line symmetry relationship is read out. Further, the light source drive value calculation unit 24 uses the center line LXc and the center as information on the light intensity distribution that the light source 57F on the other side of the center line LYc of the second sidelight light source 52B irradiates the plane of the image display panel 30. Information on the look-up table LUTA of the light source 56A that is point-symmetric with respect to the center point PR where the line LYc intersects is read. The information on the luminance of each pixel 48 of the image display panel 30 that has been read and stored is superimposed and approximated to the (1 / α) value analyzed by the image analysis unit 23, so that the light sources 56A, 56B, and 56C. 56D, 56E, 56F, 57A, 57B, 57C, 57D, 57E and 57F. Thereby, the light source drive value calculation unit 24 can reduce the amount of calculation by replacing complicated calculation processing with reference processing of simple lookup tables LUTA, LUTB, LUTC, LUTD, LUTE, and LUTF. And the lookup table capacity to be stored in advance is greatly reduced.

  In the above description, the center line LXc and the center line LYc are the center lines of the light guide plate 54. However, when the center line of the effective region of the light guide plate 54 is different from the center line of the light guide plate 54, the center line LXc and the center line LYc is the center line of the effective area of the light guide plate 54.

(Application example)
Next, an application example of the display device 10 described in the present embodiment and the modification will be described with reference to FIGS. Hereinafter, this embodiment and a modification will be described as this embodiment. 16 to 24 are diagrams illustrating examples of electronic apparatuses to which the display device according to this embodiment is applied. The display device 10 according to the present embodiment is an electronic device in various fields such as a mobile terminal device such as a mobile phone or a smartphone, a television device, a digital camera, a notebook personal computer, a video camera, or a meter provided in a vehicle. It is possible to apply to. In other words, the display device 10 according to the present embodiment can be applied to electronic devices in all fields that display an externally input video signal or an internally generated video signal as an image or video. The electronic device includes a control device that supplies a video signal to the display device 10 and controls the operation of the display device 10.

(Application example 1)
The electronic apparatus shown in FIG. 16 is a television apparatus to which the display device 10 according to the present embodiment is applied. This television apparatus has, for example, a video display screen unit 510 including a front panel 511 and a filter glass 512, and the video display screen unit 510 is the display device 10 according to the present embodiment.

(Application example 2)
The electronic apparatus shown in FIGS. 17 and 18 is a digital camera to which the display device 10 according to the present embodiment is applied. The digital camera includes, for example, a flash light emitting unit 521, a display unit 522, a menu switch 523, and a shutter button 524, and the display unit 522 is the display device 10 according to the present embodiment. As shown in FIG. 17, the digital camera has a lens cover 525, and the photographing lens appears by sliding the lens cover 525. The digital camera can take a digital photograph by imaging light incident from the taking lens.

(Application example 3)
The electronic device shown in FIG. 19 represents the appearance of a video camera to which the display device 10 according to the present embodiment is applied. This video camera has, for example, a main body 531, a subject photographing lens 532 provided on the front side surface of the main body 531, a start / stop switch 533 during photographing, and a display 534. The display unit 534 is the display device 10 according to the present embodiment.

(Application example 4)
The electronic apparatus shown in FIG. 20 is a notebook personal computer to which the display device 10 according to this embodiment is applied. The notebook personal computer includes, for example, a main body 541, a keyboard 542 for inputting characters and the like, and a display unit 543 that displays an image. The display unit 543 is the display device 10 according to the present embodiment. is there.

(Application example 5)
The electronic device illustrated in FIGS. 21 and 22 is a mobile phone to which the display device 10 is applied. FIG. 21 is a front view of the mobile phone with the mobile phone opened. FIG. 22 is a front view of the cellular phone folded. For example, the mobile phone includes an upper housing 551 and a lower housing 552 connected by a connecting portion (hinge portion) 553, and includes a display 554, a sub-display 555, a picture light 556, and a camera 557. Yes. The display device 10 is attached to the display 554. Note that the display 554 of the mobile phone may have a function of detecting a touch operation in addition to a function of displaying an image.

(Application example 6)
The electronic device illustrated in FIG. 23 is an information portable terminal that operates as a portable computer, a multifunctional portable phone, a portable computer capable of voice communication, or a portable computer capable of communication, and is sometimes referred to as a so-called smartphone or tablet terminal. . This information portable terminal has a display unit 562 on the surface of a housing 561, for example. The display unit 562 is the display device 10 according to the present embodiment.

(Application example 7)
FIG. 24 is a schematic configuration diagram of a meter unit according to the present embodiment. The electronic device shown in FIG. 24 is a meter unit mounted on a vehicle. A meter unit (electronic device) 570 shown in FIG. 24 includes a plurality of display devices 10 according to the present embodiment described above as a display device 571, such as a fuel gauge, a water temperature gauge, a speedometer, and a tachometer. The plurality of display devices 571 are all covered by a single exterior panel 572.

  Each of the display devices 571 shown in FIG. 24 has a configuration in which a panel 573 as display means and a movement mechanism as analog display means are combined with each other. The movement mechanism has a motor as driving means and a pointer 574 rotated by the motor. As shown in FIG. 24, the display device 571 can display a scale display, a warning display, etc. on the display surface of the panel 573, and the movement mechanism pointer 574 rotates on the display surface side of the panel 573. Is possible.

  In FIG. 24, a plurality of display devices 571 are provided on one exterior panel 572, but the present invention is not limited to this. One display device 571 may be provided in a region surrounded by the exterior panel 572, and a fuel gauge, a water temperature meter, a speedometer, a tachometer, or the like may be displayed on the display device 571.

DESCRIPTION OF SYMBOLS 10 Display apparatus 20 Signal processing part 30 Image display panel 40 Image display panel drive part 41 Signal output circuit 42 Scan circuit 48 Pixel 49 Sub pixel 49R 1st sub pixel 49G 2nd sub pixel 49B 3rd sub pixel 49W 4th sub pixel 50 Planar light source device 52, 52A, 52B Side light source 54 Light guide plate 56A, 56B, 56C, 56D, 56E, 56F, 57A, 57B, 57C, 57D, 57E, 57F Light source 60 Planar light source device controller LXc Center line ( 1st center line)
LYc center line (second center line)
PR center point

Claims (11)

An image display panel;
A planar light source comprising: a light guide plate that illuminates the image display panel from the back; and a sidelight light source in which a plurality of light sources are arranged at positions opposite to the incident surface with at least one side surface of the light guide plate as an incident surface. When,
A control unit that controls brightness independently for each light source,
The control unit stores, as a look-up table for each light source, information on a light intensity distribution in which incident light incident from the light source is irradiated onto the plane of the image display panel via the light guide plate. A display device that controls a light source lighting amount of each light source based on information of an input signal and each lookup table.   The display device according to claim 1, wherein the control unit obtains luminance information in each pixel of the image display panel from the information on the light source lighting amount and the information on the lookup table by interpolation calculation.   The luminance information in each pixel of the image display panel is processed by polynomial interpolation for the light source array direction that is the direction along the one side surface, and by linear interpolation for the light incident direction orthogonal to the light source array direction. The display device according to claim 1, wherein the interpolation calculation is performed. The controller is
Storing the look-up table for the light source on one side of the center line indicating the center of the light guide plate in the light source arrangement direction that is a direction along the one side surface;
The information of a look-up table of a light source that is line-symmetric with respect to the center line is read out as information on a light intensity distribution that a light source on the other side of the center line irradiates a plane of the image display panel. The display device according to any one of claims 1 to 3. The planar light source includes the sidelight light source as a first sidelight light source, one side surface of the light guide plate as a first incident surface, and the other side surface opposite to the one side surface of the light guide plate as a second incident surface. A second sidelight light source in which a plurality of light sources are arranged at a position facing the second incident surface,
The controller is
Storing a lookup table of the first sidelight light source;
The information of the look-up table of the light source in the one side which opposes is read as information on the light intensity distribution which the light source of the said 2nd sidelight light source irradiates to the plane of the said image display panel. The display device according to claim 1. The planar light source includes the sidelight light source as a first sidelight light source, one side surface of the light guide plate as a first incident surface, and the other side surface opposite to the one side surface of the light guide plate as a second incident surface. A second sidelight light source in which a plurality of light sources are arranged at a position facing the second incident surface,
The controller is
Storing the look-up table for the light source on one side of the first center line indicating the center of the light guide plate in the light source arrangement direction that is a direction along the one side surface;
As information on the light intensity distribution that the light source on the other side of the first center line irradiates the plane of the image display panel, information on the look-up table of the light source that is axisymmetric with respect to the first center line is used. reading,
A second light source that indicates the center of the one side surface and the other side surface as information on the light intensity distribution that the light source on one side of the second sidelight light source emits to the plane of the image display panel. Read the information of the look-up table of the light source that is axisymmetric with respect to the center line,
The second center line and the first center line intersect as information on the light intensity distribution that the light source on the other side of the second side light source irradiates the plane of the image display panel. The display device according to any one of claims 1 to 3, wherein information on a look-up table of a light source that is point-symmetric with respect to a center point to be read is read out.   7. The control unit according to claim 1, wherein the control unit corrects an input signal of the image based on information on luminance in each pixel of the image display panel, and displays the image on the image display panel. The display device according to item.   The pixels arranged in a matrix on the image display panel include a first subpixel that displays a first color, a second subpixel that displays a second color, a third subpixel that displays a third color, and The display device according to claim 1, further comprising a fourth sub-pixel that displays a fourth color.   The display device according to claim 1, wherein the control unit corrects a deviation between the light source and the light guide plate.   An electronic device comprising the display device according to any one of claims 1 to 9. An image display panel;
A planar light source comprising: a light guide plate that illuminates the image display panel from the back; and a sidelight light source in which a plurality of light sources are arranged at positions opposite to the incident surface with at least one side surface of the light guide plate as an incident surface. A method of driving a display device comprising:
An input signal detection step for detecting an input signal of the image;
An image analysis step for analyzing the image;
A result of analyzing the image; and a lookup table for each light source storing information on a light intensity distribution in which incident light incident from the light source is irradiated onto a plane of the image display panel via the light guide plate; And a light source lighting amount calculation step of calculating a light source lighting amount of the light source.

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