JP6985808B2 - Display device and drive method of display device - Google Patents

Description

The present invention relates to a display device and a method for driving the display device.

A display device having a local dimming function that divides a light source device such as a backlight into a plurality of regions and controls light emission of the light source for each region according to a video signal in the divided regions is known (for example, Patent Document). 1).

Japanese Unexamined Patent Publication No. 2013-246426

From the viewpoint of power saving, it is desirable to turn off the light source in an area where the video output can be achieved even if the light source is turned off. However, conventionally, when video output that requires light from a light source is performed in each of the divided regions (for example, video output containing one or more pixels of a color other than black), the light from the light source corresponding to that region is used. Control was performed to secure the required brightness in that area, and it was difficult to save power.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a display device capable of further power saving and a method for driving the display device.

The display device according to one aspect of the present invention has a plurality of light sources arranged along at least one direction and a display area provided with a plurality of pixels, and outputs an image illuminated by light from the plurality of light sources. A display unit and a control unit that controls the operation of the light source based on the display output content of the display unit are provided, and the display area is divided into a plurality of partial areas associated with each of the plurality of light sources. , The partial region is illuminated by the light from the first light source associated with the partial region and the light from the first light source and the second light source adjacent to the first light source, respectively. The control unit has a second region, and the control unit receives light required for display output by the necessity of light from the first light source in the first region and the light from the second light source in the second region. The operation of the first light source is controlled based on whether or not it is obtained.

In the method of driving the display device according to the other aspect, the display device has a plurality of light sources arranged along at least one direction and a display area provided with a plurality of pixels, and the light from the plurality of light sources is used. A display unit that outputs an illuminated image and a control unit that controls the operation of the light source based on the display output content of the display unit are provided, and the display area is associated with each of the plurality of light sources. The subregions are divided into a plurality of subregions, each of which is a first region illuminated by light from a first light source associated with the subregion, a first light source, and a first light source adjacent to the first light source. It has a second region illuminated by light from two light sources, and the driving method is the necessity of light from the first light source in the first region and from the second light source in the second region. The operation of the first light source is controlled based on whether or not the light required for the display output can be obtained by the light.

FIG. 1 is a schematic view showing a main configuration of a display device according to an embodiment of the present invention. FIG. 2 is a block diagram showing a system configuration example of the display unit according to the present embodiment. FIG. 3 is a circuit diagram showing a drive circuit for driving the pixels of the display unit according to the present embodiment. FIG. 4 is a diagram showing an example of division of the display area. FIG. 5 is a diagram showing an example of a correspondence relationship between a plurality of light sources included in the light source unit and a plurality of partial regions. FIG. 6 is a schematic diagram illustrating the first region and the second region of one partial region. FIG. 7 is a graph showing an example of the relationship between the luminance distribution of four continuous partial regions in one direction and the required luminance obtained in one partial region. FIG. 8 is a flowchart showing an example of processing related to lighting control of the first light source. FIG. 9 is a graph showing an example in which the brightness required for the second region of one partial region is secured by the light from the light source associated with the one partial region and the light source adjacent to the light source. FIG. 10 is a graph showing an example of the relationship between the brightness of light required in the second region and a predetermined threshold value.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the disclosure is merely an example, and those skilled in the art can easily conceive of appropriate changes while maintaining the gist of the invention, which are naturally included in the scope of the present invention. Further, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc. of each part as compared with the actual embodiment, but this is just an example, and the interpretation of the present invention is used. It is not limited. Further, in the present specification and each figure, the same elements as those described above with respect to the above-mentioned figures may be designated by the same reference numerals, and detailed description thereof may be omitted as appropriate.

FIG. 1 is a schematic view showing a main configuration of a display device 1 according to an embodiment of the present invention. The display device 1 has, for example, a light source unit 6 that functions as a light source device, a display unit 2 that outputs an image using the light L from the light source unit 6 as a light source, and the like. The light L emitted from the light source unit 6 is reflected by the display unit 2, the mirror M, and the windshield FG to reach the user H, and is recognized as an image VI in the user's field of view. That is, the display device 1 of the present embodiment functions as a head-up display (HUD) using the mirror M and the windshield FG.

Next, the display unit 2 will be described. The display unit 2 of the present embodiment is a transmissive liquid crystal display that outputs an image using light L as a light source, but is a reflective liquid crystal display and a digital micromirror device (DMD (registered trademark)). And so on.

FIG. 2 is a block diagram showing a system configuration example of the display unit 2 according to the present embodiment. FIG. 3 is a circuit diagram showing a drive circuit for driving the pixel Pix of the display unit 2 according to the present embodiment. The pixel Pix includes a plurality of sub-pixels Vpix. The display unit 2 is, for example, a transmissive liquid crystal display, and includes an image output panel and a driving element 3, for example, a DDIC (Display Driver Integrated Circuit).

The image output panel is, for example, a translucent insulating substrate, for example, a glass substrate, and a display in which a large number of pixels Pix (see FIG. 3) including liquid crystal cells are arranged in a matrix (matrix) on the surface of the glass substrate. It has a region 21. The glass substrate is a first substrate in which a large number of pixel circuits including active elements (for example, transistors) are arranged and formed in a matrix, and a second substrate in which the first substrate is arranged so as to face each other with a predetermined gap. It is composed of a substrate. The gap between the first substrate and the second substrate is held in a predetermined gap by photo spacers arranged and formed at various places on the first substrate. Then, a liquid crystal display is enclosed between the first substrate and the second substrate. The arrangement and size of each part shown in FIG. 2 are schematic and do not reflect the actual arrangement or the like.

The display area 21 has a matrix structure in which sub-pixels Vpix including a liquid crystal layer are arranged in M rows × N columns. In this specification, the row means a pixel row having N sub-pixels Vpix arranged in one direction. Further, the column means a pixel column having M sub-pixels Vpix arranged in a direction orthogonal to the direction in which the rows extend. The values of M and N are determined according to the vertical resolution and the horizontal resolution. The display area 21, the scanning lines ₂₄ 1 for each row to the sequence of M rows and N columns of sub-pixels _Vpix, 24 _2, 24 3, ..., is wired 24 _M, the signal line ₂₅ 1 in each column, 25 ₂ , 25 ₃ , ..., 25 _N are wired. Thereafter, in the present embodiment, the scanning lines _{24 1,} 24 _2, 24 3, ..., on behalf of the 24 _M was expressed as the scanning lines 24, signal lines _{25 1,} 25 _2, 25 3, ..., 25 _It may be expressed as signal line 25 on behalf of N. In the present embodiment, the scanning lines _{24 1,} 24 _2, 24 3, ..., any three scanning lines 24 _M, the scan lines _{24 m, 24 m + 1,} 24 m + 2 ( however, m is, m notation is as natural number) satisfying ≦ M-2, the signal lines _{25 1,} 25 _2, 25 3, ..., any three signal lines 25 _n, the signal line _{25 n, 25 n + 1,} 25 n + 2 ( However, n is expressed as a natural number satisfying n ≦ N-2).

The drive element 3 is a circuit mounted on a glass substrate of an image output panel by, for example, COG (Chip On Glass). The drive element 3 is connected to the control unit 100 via a flexible printed circuit board (FPC) (not shown). The control unit 100 is a circuit that controls the operation of the display unit 2 and the light source unit 6. Specifically, the control unit 100 functions as, for example, a display control unit 101 and a light source control unit 102. The display control unit 101 outputs a pixel signal for individually driving a plurality of sub-pixels Vpix constituting the pixel Pix. The pixel signal is, for example, a signal in which individual gradation values of red (R), green (G), blue (B), and white (W), which will be described later, are combined. The type and number of colors to be associated are arbitrary. Further, the display control unit 101 has a function of controlling the output gradation value of a part or all of the plurality of pixels based on the light emission amount of the light source 6a controlled by the light source control unit 102. The light source control unit 102 controls the operation of the light source 6a based on the display output content of the display unit 2. Specifically, the light source control unit 102 individually controls the operation of the plurality of light sources 6a constituting the light source unit 6. Further, the control unit 100 may have a function of outputting various signals (for example, a master clock, a horizontal synchronization signal, a vertical synchronization signal, etc.) used for the operation of the display unit 2. The configuration for outputting the various signals may be provided separately.

In the present embodiment, the light source control unit 102 employs so-called one-frame delay control that controls the operation of the plurality of light sources 6a based on the pixel signal output by the display control unit 101 one frame before. By the one-frame delay control, it is possible to omit the buffer for holding the pixel signal, which is required when trying to control the operation of the plurality of light sources 6a in the same frame as the pixel signal. A buffer may be provided to control the operation of the plurality of light sources 6a in the same frame as the pixel signal.

Further, the display unit 2 is connected to an external input power supply or the like (not shown). The power required for the operation of the display unit 2 is supplied from the external input power supply.

More specifically, the drive element 3 operates the display unit 2 in response to various signals given from, for example, the control unit 100. The control unit 100 outputs, for example, a master clock, a horizontal synchronization signal, a vertical synchronization signal, a pixel signal, a drive command signal of the light source unit 6, and the like to the drive element 3. The drive element 3 functions as a gate driver and a source driver based on these signals and the like. In addition, one or both of a gate driver and a source driver may be formed on a substrate by using a thin film transistor (TFT) described later. In that case, one or both of the gate driver and the source driver may be electrically connected to the drive element 3. Further, the source driver and the gate driver may be electrically connected to different drive elements 3 or may be connected to the same drive element 3.

The gate driver latches digital data in units of one horizontal period corresponding to the horizontal synchronization signal in synchronization with the vertical synchronization signal and the horizontal synchronization signal. The gate driver outputs sequentially latched digital data for one line has been as a vertical scanning pulse, the scanning lines 24 in the display region 21 (scanning lines _{24 1,} 24 _2, 24 3, ..., 24 _M) by giving the Sub-pixel Vpix is sequentially selected row by row. The gate driver, for example, the row direction, the scanning lines 24 _1, 24 2, and outputs the digital data in the order from _... one end of the display area 21 to the other end side. Further, the gate driver can also output digital data in order from the other end side to the one end side of the display area 21 of the _{scanning line 24 M, ... In the row direction.}

The source driver is given, for example, pixel drive data generated based on a pixel signal. _{The source driver has a signal line 25 (signal lines 25 1} , 25) for each sub-pixel Vpix in the row selected by vertical scanning by the gate driver, for each sub-pixel, for each of a plurality of sub-pixels, or for all sub-pixels at once. ₂ , 25 ₃ , ..., 25 _N ), and the data for pixel drive is written.

As a drive method for a liquid crystal display, drive methods such as line inversion, dot inversion, and frame inversion are known. Line inversion is a drive method in which the polarity of a video signal is inverted in a time cycle of 1H (H is a horizontal period) corresponding to one line (one pixel line). Dot inversion is a drive method in which the polarities of video signals are alternately inverted for each sub-pixel adjacent to each other in two intersecting directions (for example, matrix direction). The frame inversion is a drive method in which the video signals written to all the sub-pixels Vpix are inverted at once with the same polarity for each frame corresponding to one screen. The display unit 2 can adopt any of the above-mentioned drive methods.

In the description of this embodiment, the scanning lines ₂₄ 1 of the _M, 24 _2, 24 3, ..., when dealing with comprehensive each of 24 _M, may be referred to as a scanning line 24. The scanning lines 24 _m , 24 _{m + 1} , and 24 _{m + 2} in FIG. 3 are _{a part of} M scanning lines 24 ₁ , 24 ₂ , 24 ₃ , ..., 24 _M. Further, when each of N signal lines 25 ₁ , 25 ₂ , 25 ₃ , ..., 25 _N is comprehensively handled, it may be described as signal line 25. The signal lines 25 _n , 25 _{n + 1} , 25 _{n + 2} in FIG. 3 are a part of N signal lines 25 ₁ , 25 ₂ , 25 ₃ , ..., 25 _N.

Wiring such as a signal line 25 for supplying a pixel signal to the TFT element Tr of the sub-pixel Vpix and a scanning line 24 for driving each TFT element Tr is formed in the display area 21. In this way, the signal line 25 extends in a plane parallel to the surface of the glass substrate described above, and supplies data for driving pixels generated based on the pixel signal for outputting an image to the sub-pixel Vpix. .. The sub-pixel Vpix includes a TFT element Tr and a liquid crystal element LC. The TFT element Tr is composed of a thin film transistor, and in this example, it is composed of an n-channel MOS (Metal Oxide Semiconductor) type TFT. One of the source or drain of the TFT element Tr is connected to the signal line 25, the gate is connected to the scanning line 24, and the other of the source or drain is connected to one end of the liquid crystal element LC. One end of the liquid crystal element LC is connected to the other of the source or drain of the TFT element Tr, and the other end is connected to the common electrode COM. A drive signal is applied to the common electrode COM by a drive electrode driver (not shown). The drive electrode driver may be a configuration of the drive element 3 or may be an independent circuit.

The sub-pixel Vpix is connected to each other by a scanning line 24 with another sub-pixel Vpix belonging to the same row in the display area 21. The scanning line 24 is connected to a gate driver, and a vertical scanning pulse of a scanning signal is supplied from the gate driver. Further, the sub-pixel Vpix is connected to each other by a signal line 25 with another sub-pixel Vpix belonging to the same column of the display area 21. The signal line 25 is connected to the source driver, and a pixel signal is supplied from the source driver. Further, the sub-pixel Vpix is connected to each other by a common electrode COM with other sub-pixel Vpix belonging to the same row of the display area 21. The common electrode COM is connected to a drive electrode driver (not shown), and a drive signal is supplied from the drive electrode driver.

The gate driver applies a vertical scanning pulse to the gate of the TFT element Tr of the sub-pixel Vpix via the scanning line 24, so that one row of the sub-pixel Vpix formed in a matrix in the display region 21 ( 1 Horizontal line) is sequentially selected as the target of image output. The source driver supplies the pixel signal via the signal line 25 to the sub-pixel Vpix included in one horizontal line sequentially selected by the gate driver. Then, in these sub-pixel Vpix, one horizontal line image output is performed according to the supplied pixel signal.

As described above, the display unit 2 sequentially selects one horizontal line by driving the gate driver so as to sequentially scan the scanning lines 24. Further, the display unit 2 outputs an image for each horizontal line by supplying a pixel signal to the sub-pixel Vpix belonging to one horizontal line via the signal line 25 by the source driver. When performing this image output operation, the drive electrode driver applies a drive signal to the common electrode COM corresponding to the one horizontal line.

Further, the display area 21 has a color filter. The color filter has a grid-shaped black matrix 76a and an opening 76b. As shown in FIG. 3, the black matrix 76a is formed so as to cover the outer periphery of the sub-pixel Vpix. That is, the black matrix 76a has a grid shape by being arranged at the boundary between the two-dimensionally arranged sub-pixel Vpix and the sub-pixel Vpix. The black matrix 76a is made of a material having a high light absorption rate. The opening portion 76b is an opening formed in a grid shape of the black matrix 76a, and is arranged corresponding to the sub-pixel Vpix.

The opening 76b includes a color region corresponding to three colors (eg, R (red), G (green), B (blue)) or four colors of subpixel Vpix. Specifically, the opening 76b is colored, for example, into three colors, red (R), green (G), and blue (B), which are a form of the first color, the second color, and the third color. A color region of a fourth color (for example, white (W)) is included. The color filter periodically arranges color regions colored in three colors, for example, red (R), green (G), and blue (B), in the opening 76b. When the fourth color is white (W), the opening 76b of the white (W) is not colored by the color filter. When the fourth color is another color, the color adopted as the fourth color is colored by the color filter. In the present embodiment, each sub-pixel Vpix shown in FIG. 3 is associated with a total of four colors, that is, a color region of three colors R, G, and B and a fourth color (for example, W) as a set of pixels Pix. There is. The pixel signal for one pixel in the present embodiment is to the output of one pixel Pix having the sub-pixel Vpix of red (R), green (G), blue (B) and the fourth color (white (W)). The corresponding pixel signal. In the description of this embodiment, red (R), green (G), blue (B), and white (W) may be simply described as R, G, B, and W. When the pixel Pix includes sub-pixel Vpix having two or less colors or five or more colors, digital data according to the number of colors may be supplied based on the original data of the image.

The color filter may be a combination of other colors as long as it is colored in a different color. In general, in a color filter, the brightness of the green (G) color region is higher than the brightness of the red (R) color region and the blue (B) color region. Further, when the fourth color is white (W), a light-transmitting resin may be used for the color filter to make it white.

The display area 21 is arranged in an area where the scanning line 24 and the signal line 25 overlap with the black matrix 76a of the color filter when viewed from a direction orthogonal to the front surface. That is, the scanning line 24 and the signal line 25 are hidden behind the black matrix 76a when viewed from the direction orthogonal to the front surface. Further, in the display area 21, the area where the black matrix 76a is not arranged becomes the opening 76b.

FIG. 4 is a diagram showing an example of division of the display area 21. The display area 21 is divided into a plurality of partial areas. Specifically, for example, as shown in FIG. 4, the display area 21 is divided into eight equal parts _{along the X direction, such as X 1} , X ₂ , ..., X _{8 , and Y 1} , 1, along the Y direction. A partial area of 8 × 4 is provided by being divided into four equal parts such as Y ₂ , Y ₃ , and Y _4. As an example, in the case of the display area 21 in which 800 pixels in the X direction and 480 pixels in the Y direction, that is, 800 × 480 pixel Pix are arranged in a matrix, one partial area shown in FIG. 4 is a 100 × 120 pixel Pix. Has. The example shown in FIG. 4 and the number of pixels in the display area 21 are merely examples and are not limited to this, and can be changed as appropriate.

FIG. 5 is a diagram showing an example of a correspondence relationship between a plurality of light sources 6a included in the light source unit 6 and a plurality of partial regions. The arrangement of the light source 6a shown in FIG. 5 corresponds to the division of the partial region shown in FIG. The plurality of partial regions are associated with each of the plurality of light sources 6a included in the light source unit 6. Specifically, for example, as shown in FIG. 5, one light source 6a is arranged in each of the plurality of partial regions. The light source 6a is, for example, a light emitting diode (LED), but this is an example of a specific configuration of the light source 6a and is not limited to this, and can be appropriately changed. Further, in FIG. 5, one light source 6a is arranged in each of the partial regions, but the amount of light emitted can be controlled individually in each of the partial regions, and the brightness of each partial region can be adjusted. If there is, it is not limited to this and can be changed as appropriate.

It should be noted that the light from each of the plurality of light sources 6a is not radiated only to the strictly corresponding partial region, but is brought to the partial region near the corresponding partial region. Therefore, for example, when two light sources 6a corresponding to two adjacent partial regions are both lit, the two partial regions are irradiated with the combined light of the light of the two light sources 6a. obtain.

FIG. 6 is a schematic diagram illustrating the first region C and the second regions XA, XB, YA, YB, XAYA, XBYA, XAYB, and XBYB of one partial region. The partial regions are the first region illuminated by the light from the light source 6a (first light source) associated with the partial region, the first light source, and the light source 6a (second light source) adjacent to the first light source, respectively. It has a second region illuminated by light from. Specifically, as shown in FIG. 6, for example, the partial region has a first region C located in the center of the partial region and a second region located on both ends of the m pixel width in the X direction with the first region C interposed therebetween. It has regions XA, XB, second regions YA, YB, etc. located on both ends of the m pixel width in the Y direction with the first region C interposed therebetween. The second regions XAYA, XBYA, XAYB, and XBYB of m × m [pixels] located at the four corners of the rectangular partial region may be independent second regions, and are the same in the X direction or the Y direction. It may be part of a second region at the location. For example, XAYA may be an independent second region, a part of the second region XA, or a part of the second region YA. m is an arbitrary value (natural number), for example, m = 8. Further, the pixel widths of the second regions XA and XB on both ends in the X direction and the pixel widths of the second regions YA and YB on both ends in the Y direction can be set individually.

FIG. 7 shows an example of the relationship between the brightness distribution of four continuous partial regions (n-1), n, (n + 1), and (n + 2) in one direction and the required brightness obtained in one partial region (n + 1). It is a graph which shows. The horizontal axis of FIG. 7 and FIGS. 9 and 10 described later is either the X direction or the Y direction. Conventionally, when the pixel Pix is driven by an output gradation value that requires light from the light source 6a in a certain partial region (for example, the partial region (n + 1)), it is associated with the one partial region. The light source 6a lights up. To give a specific example, for example, when the pixel Pix included in the partial region (n + 1) is driven by the output gradation value requiring the luminance of the cross mark shown in FIG. 7, as shown by the luminance distribution of the broken line P2, as shown by the luminance distribution of the broken line P2. The light source 6a associated with the partial region (n + 1) lights up.

However, for example, as shown by line P1 in FIG. 7, the luminance distribution obtained by lighting the light source 6a associated with the region (for example, the partial region n) adjacent to the partial region (n + 1) is the partial region (n + 1). ), It is not necessary to turn on the light source 6a associated with the partial region (n + 1) when the required brightness can be secured for the pixel Pix included in the partial region (n + 1). Specifically, assuming that the light source 6a in the partial region n is the second light source and the light source 6a in the partial region (n + 1) is the first light source, the light from the first light source and the second light source adjacent to the first light source is used. For the second region of the illuminated partial region (n + 1), the relationship of the partial regions n and (n + 1) in FIG. 7 holds. That is, when the light required in the second region of the partial region (n + 1) is obtained from the light source 6a associated with the partial region n, the light source 6a associated with the partial region (n + 1) is not necessarily turned on. You do not have to let it. However, even in this case, if light is required in the first region illuminated by the light from the light source 6a associated with the partial region (n + 1), the light source associated with the partial region (n + 1) is required. It is necessary to light 6a.

Therefore, in the present embodiment, the control unit 100 determines the necessity of light from the first light source (for example, the light source 6a associated with the partial region (n + 1) in FIG. 7) in the first region and the second region. The operation of the first light source is controlled based on whether or not the light required for the display output can be obtained from the light from the two light sources (for example, the light source 6a associated with the partial region n in FIG. 7). Specifically, the control unit 100 that functions as the light source control unit 102 does not require the light from the first light source in the first region, and is required for display output by the light from the second light source in the second region. The first light source is turned off when the light is obtained.

FIG. 8 is a flowchart showing an example of processing related to lighting control of the first light source. The control unit 100 determines whether or not light from the first light source is required in the first region (step S1). When it is determined that the light from the first light source is required in the first region (step S1; Yes), the control unit 100 turns on the first light source (step S2). When it is determined that the light from the first light source is not required in the first region (step S1; No), the control unit 100 obtains the light from the second light source required for the display output in the second region. Whether or not it is determined (step S3). When it is determined that the light from the second light source can obtain the light required for the display output of the second region (step S3; Yes), the control unit 100 turns off the first light source (step S4). When it is determined that the light from the second light source does not provide the light required for the display output of the second region (step S3; No), the control unit 100 turns on the first light source (step S2).

FIG. 9 is a graph showing an example in which the brightness required for the second region of one partial region is secured by the light from the light source 6a associated with the one partial region and the light source 6a adjacent to the light source 6a. .. The combination of the reference numerals A and B in FIG. 9 is either a combination of the second regions XA and XB or a combination of the second regions YA and YB.

In the example shown in FIG. 9, the light source 6a associated with the partial region n is lit so as to have the luminance distribution shown by the line P1 according to the luminance al required in the first region L1_c of the partial region n. At this time, it is assumed that light having a luminance bl is required in the second region L2_l at a position adjacent to the partial region n in the second region of the partial region (n + 1). Here, the luminance distribution due to the light from the light source 6a associated with the partial region n indicated by the line P1 brings the luminance bl or more to the second region L2_l. That is, the brightness required for the second region L2_l is sufficiently secured by the light from the light source 6a associated with the partial region n. Further, in the example shown in FIG. 9, light is not required in the second region other than the first region L2_c and the second region L2_l of the partial region (n + 1). In this case, the partial region (n + 1) does not require the light from the light source 6a associated with the partial region (n + 1) in the first region, and the second light source (for example, the partial region n) in the second region. This is a state in which the light required for the display output can be obtained from the light from the light source 6a) associated with. Therefore, the light source control unit 102 turns off the light source 6a associated with the partial region (n + 1).

More specifically, the light source control unit 102 compares, for example, the luminance bl with the value (al × Coef) obtained by multiplying the luminance al by a predetermined coefficient Coef, and when bl <(al × Coef) is established. , The light source 6a associated with the partial region (n + 1) is turned off. The predetermined coefficient Coef is a coefficient that can take a value of 0 or more and 1 or less, and is lit according to the brightness (for example, brightness al) required in the first region (for example, the first region L1_c) of a certain partial region. This is a coefficient for calculating the brightness brought to the second region (for example, L2_l) at a position adjacent to the partial region among the second regions of the partial region adjacent to the partial region by the light source 6a. The light source control unit 102 holds information indicating the brightness distribution of each of the plurality of light sources 6a that can change depending on the magnitude of the brightness required in the first region regardless of the coefficient Coef, and the adjacent first light source control unit 102 holds the information indicating the brightness distribution of each of the plurality of light sources 6a. The brightness of the light brought to the two regions, that is, the brightness corresponding to the above (al × Coef) may be specified. The luminance required in each region (for example, luminance al, bl, etc.) is specified by the control unit 100 according to the output gradation value of each region. Specifically, the control unit 100 holds, for example, information in which the output gradation value and the brightness required for the pixel Pix driven by the output gradation value are associated with each other.

In FIG. 9, for the purpose of simplifying the explanation, the description is limited to the relationship between one partial region (second region L2_l) and the light source 6a associated with the partial region n, but in reality, the light source is used. The control unit 102 makes the same determination for all the second regions for each partial region.

First, a case where the second region XAYA, XBYA, XAYB, and XBYB are treated as a part of the second region at the same position in the X direction or the Y direction will be described. For example, the light source control unit 102 first sets a predetermined flag value (for example, Deepblack Flag: DF) in the first region C and the second region XA, XB, YA, and YB shown in FIG. 6 as a predetermined initial value (for example, for example). Set in 1). The light source control unit 102 determines whether or not there is a pixel Pix having an output gradation value that requires light in the first region C. When it is determined that there is a pixel Pix having an output gradation value that requires light in the first region C, the light source control unit 102 changes the value of the DF in the first region C. Specifically, for example, the value of DF is set to 0.

Further, the light source control unit 102 determines whether or not there is a pixel Pix having an output gradation value that requires light in the second region XA. When it is determined that the second region XA has a pixel Pix having an output gradation value that requires light, the light source control unit 102 determines that the brightness of the light required in the second region XA (for example, brightness bl) and the first. The two regions XA are compared with the luminance provided by the light from the light source 6a associated with the adjacent partial region (for example, al × Coef), and the luminance required for the second region XA by the light from the light source 6a is obtained. Determine if it can be secured sufficiently. When it is determined that the light from the light source 6a cannot sufficiently secure the brightness required for the second region XA, the light source control unit 102 changes the value of the DF of the second region XA. The light source control unit 102 also performs the same determination as in the second region XA for the second region XB, YA, and YB, and changes the DF value according to the determination result.

The light source control unit 102 checks whether or not all the DFs set in the first region C and the second region XA, XB, YA, and YB of the partial region are initial values, and if they are all initial values, the relevant portion. The light source 6a associated with the area is turned off. On the other hand, when at least one DF is not an initial value, the light source 6a associated with the partial region is turned on.

Next, a case where the second region XAYA, XBYA, XAYB, and XBYB are treated as independent second regions will be described. For example, the light source control unit 102 first assigns a predetermined flag value (for example, DF) to the first region C and the second region XA, XB, YA, YB, XAYA, XBYA, XAYB, and XBYB shown in FIG. Set with the initial value (for example, 1). The light source control unit 102 determines whether or not there is a pixel Pix having an output gradation value that requires light in the first region C. When it is determined that there is a pixel Pix having an output gradation value that requires light in the first region C, the light source control unit 102 changes the value of the DF in the first region C. Specifically, for example, the value of DF is set to 0.

Further, the light source control unit 102 determines whether or not there is a pixel Pix having an output gradation value that requires light in the second region XA. When it is determined that the second region XA has a pixel Pix having an output gradation value that requires light, the light source control unit 102 determines that the brightness of the light required in the second region XA (for example, brightness bl) and the first. The two regions XA are compared with the luminance provided by the light from the light source 6a associated with the adjacent partial region (for example, al × Coef), and the luminance required for the second region XA by the light from the light source 6a is obtained. Determine if it can be secured sufficiently. When it is determined that the light from the light source 6a cannot sufficiently secure the brightness required for the second region XA, the light source control unit 102 changes the value of the DF of the second region XA. The light source control unit 102 makes the same determination as for the second region XA for the second region XB, YA, YB, XAYA, XBYA, XAYB, and XBYB, and changes the DF value according to the determination result.

The light source control unit 102 checks whether or not all the DFs set in the first region C and the second region XA, XB, YA, YB, XAYA, XBYA, XAYB, and XBYB of the partial region are the initial values, and all of them. When it is the initial value, the light source 6a associated with the partial area is turned off. On the other hand, when at least one DF is not an initial value, the light source 6a associated with the partial region is turned on.

The light source control unit 102 individually performs the same determination and lighting control for all the partial regions. _{Specifically, for example, the partial region (X 1} , Y ₄ ) shown in FIG. 4 is set as the initial determination target, and the determination is sequentially performed along one direction (for example, the X direction), and all the determinations are made in the one direction. When the determination related to the partial area is completed, the process of sliding one in the other direction (for example, the Y direction) is sequentially repeated to sequentially execute the determination related to the setting and change of the DF for all the partial areas. The light source control unit 102 also sequentially executes lighting control.

Considering that the second region XAYA, XBYA, XAYB, and XBYB are affected by the light from the two light sources 6a associated with the two adjacent partial regions, the predetermined coefficient Coef is set to the second region XAYA, XBYA. , XAYB, XBYB and the second region XA, XB, YA, YB may have different values. Further, the light from the light source 6a associated with the adjacent partial regions in the second regions XA and XB and the second regions YA and YB so that the partial region of the present embodiment has the pixel Pix of 100 × 120. Considering that the degree of influence may be different, the predetermined coefficient Coef may be set to a different value in the second region XA, XB and the second region YA, YB. Further, in consideration of individual differences of the light sources 6a of each of the plurality of partial regions, a predetermined coefficient Coef may be individually set in the partial regions.

As described above, according to the present embodiment, it is based on whether or not the light from the first light source in the first region is necessary and whether or not the light from the second light source in the second region can obtain the light required for the display output. Controls the operation of the first light source. As a result, when the light from the first light source is unnecessary in the first region and the light required for the display output is obtained by the light from the second light source in the second region, the first light source is turned off. Therefore, the power consumption can be reduced as compared with the case where the first light source is turned on. Therefore, it is possible to provide a display device capable of further power saving.

(Modification example)
Hereinafter, a modified example of the embodiment according to the present invention will be described. Regarding the description of the modified example, the same reference numerals may be given to the same configurations as those of the embodiments, and the description may be omitted. The control unit 100 that functions as the light source control unit 102 controls the operation of the second light source that can illuminate the second region based on the comparison result between the brightness of the light required in the second region and a predetermined threshold value. You may.

FIG. 10 is a graph showing an example of the relationship between the brightness of light required in the second region and a predetermined threshold value. The brightness of the light required in the second region L2_l is L2_lq, the brightness of the light required in the first region L1_c associated with the second light source is L1_cq, and the first coefficient (Coef1) of 0 or more and 1 or less is set in L1_cq. When the multiplied first threshold value is T1 and the luminance of the first region L1_c due to the lighting of the second light source is BL1, the control unit 100 functioning as the light source control unit 102 is when the equation (1) is satisfied. The second light source is turned on so as to have the brightness obtained by the equation (2). More specifically, when the second threshold value obtained by multiplying L1_cq by a second coefficient that is 0 or more and 1 or less and larger than the first coefficient is T2, the control unit 100 that functions as the light source control unit 102 is described by the equation ( When 3) is satisfied, the second light source is turned on so as to have the brightness obtained by the equation (2).
L2_lq ≧ T1 ... (1)
BL1 = L1_cq × (L2_lq / T1) ... (2)
L2_lq≤T2 ... (3)

Further, when the maximum luminance of the second light source is T3, the processing settings that can be taken by the control unit 100 that functions as the light source control unit 102 when the equation (4) holds for the luminance obtained by the equation (2) are set. There can be more than one. Hereinafter, an example of such a setting will be described in the order of setting 1, setting 2, and setting 3. Any of these plurality of settings can be arbitrarily adopted.
BL1> T3 ... (4)

(Setting 1)
The light source control unit 102 updates the luminance (BL1) of the first region L1_c due to the lighting of the second light source by the equation (5). When the update according to the equation (5) is performed, the luminance distribution of the second light source becomes, for example, the luminance distribution indicated by the broken line P3.
BL1 = T3 ... (5)

(Setting 2)
When the second coefficient is Coef2 and the brightness of the second region L2_l due to the lighting of the first light source is BL2, the light source control unit 102 obtains the brightness obtained by the equation (6) in addition to the processing of the setting 1. Turn on the first light source.
BL2 = L2_lq- (T3 x Coef2) ... (6)

(Setting 3)
When the luminance of the second region L2_l due to the lighting of the first light source is BL2, the light source control unit 102 determines the luminance when the equation (4) holds for the luminance obtained by the equation (2). The first light source is turned on so as to have the brightness obtained by the equation (8). When the first light source is turned on so as to have the luminance obtained by the equation (8), the luminance distribution of the first light source is, for example, the luminance distribution shown by the broken line P4.
BL1 = L1_cq ... (7)
BL2 = L2_lq ... (8)

As described above, according to the modified example, the brightness of the second region is more flexibly secured by controlling the operation of the second light source based on the comparison result between the brightness of the light required in the second region and the predetermined threshold value. It is possible to realize a mechanism for this.

Further, when the equation (1) is established, the operation of the second light source is controlled by the formalized luminance control by turning on the second light source so as to have the luminance obtained by the equation (2). It becomes possible to secure the required brightness in the two regions, and it is possible to realize a mechanism for more systematically securing the required brightness in the second region.

Further, when the equation (3) is satisfied, the second light source is turned on so as to have the brightness obtained by the equation (2), so that the condition suitable for the equation (2) to be adopted can be more appropriately determined. can do.

Further, by adopting the setting 1, the maximum brightness obtained without turning on the first light source can be secured in the second region.

Further, by adopting the setting 2, it is possible to secure the required brightness in the second region while minimizing the amount of light emitted from the first light source.

Further, by adopting the setting 3, it is possible to secure the required brightness in the second region without changing the light emission amount of the second light source.

In the case of setting 1, for example, the display control unit 101 may compensate the brightness of the second region by correcting the output gradation value. For example, the output gradation value of the pixel Pix that requires the highest luminance in the second region is (R, G, B, W) = (0,0,0,100), which is required in the second region. When the ratio of the brightness of light (L2_lq) to the maximum brightness (T3) of the second light source is 1.2: 1, the display control unit 101 sets (R, G, B, W) = (0,0, By correcting the output gradation value of 0,100) and setting (R, G, B, W) = (0,0,0,100,120), the brightness of the second region can be supplemented. Further, by the same mechanism, the output gradation value of the pixel Pix included in the partial region illuminated by the light of the second light source raised to the maximum luminance (T3) may be corrected.

Further, it is naturally understood that the other effects brought about by the embodiments described in the present embodiment are apparent from the description of the present specification, or those which can be appropriately conceived by those skilled in the art are brought about by the present invention. ..

Further, the present invention can be described as follows.

1. 1. With multiple light sources lined up in at least one direction,
A display unit having a display area provided with a plurality of pixels and outputting an image illuminated by light from the plurality of light sources.
A control unit that controls the operation of the light source based on the display output content of the display unit is provided.
The display area is divided into a plurality of partial areas associated with each of the plurality of light sources.
Each of the partial regions is illuminated by a first region illuminated by light from a first light source associated with the partial region, and by light from the first light source and a second light source adjacent to the first light source. It has two areas and
The control unit is based on whether or not the light from the first light source in the first region is necessary and whether or not the light from the second light source in the second region can obtain the light required for display output. A display device that controls the operation of the first light source.

2. 2. The control unit is concerned when the light from the first light source is unnecessary in the first region and the light from the second light source in the second region can obtain the light required for display output. Turn off the first light source 1. Display device described in.

3. 3. The control unit controls the operation of the second light source based on the comparison result between the brightness of light required in the second region and a predetermined threshold value. Or 2. Display device described in.

4. The brightness of the light required in the second region is L2_lq, the brightness of the light required in the first region associated with the second light source is L1_cq, and L1_cq is multiplied by the first coefficient of 0 or more and 1 or less. When the first threshold value is T1 and the brightness of the first region due to the lighting of the second light source is BL1, the control unit uses the brightness obtained by the formula (2) when the formula (1) is established. 2. Turn on the second light source so that it becomes. Display device described in.
L2_lq ≧ T1 ... (1)
BL1 = L1_cq × (L2_lq / T1) ... (2)

5. When the second threshold value obtained by multiplying L1_cq by a second coefficient that is 0 or more and 1 or less and is larger than the first coefficient is T2, the control unit uses the equation (2) when the equation (3) holds. 4. Turn on the second light source so that the required brightness is obtained. Display device described in.
L2_lq≤T2 ... (3)

6. When the maximum brightness of the second light source is T3, the control unit updates the brightness by the formula (5) when the formula (4) holds for the brightness obtained by the formula (2). Or 5. Display device described in.
BL1> T3 ... (4)
BL1 = T3 ... (5)

7. When the second coefficient is Coef2 and the brightness of the second region due to the lighting of the first light source is BL2, the control unit lights the first light source so as to have the brightness obtained by the equation (6). Let 5. Display device described in.
BL2 = L2_lq- (T3 x Coef2) ... (6)

8. When the maximum brightness of the second light source is T3 and the brightness of the second region due to the lighting of the first light source is BL2, the control unit has the formula (4) for the brightness obtained by the formula (2). When it is satisfied, the brightness is updated by the equation (7) and the first light source is turned on so as to have the luminance obtained by the equation (8). Or 5. Display device described in.
BL1> T3 ... (4)
BL1 = L1_cq ... (7)
BL2 = L2_lq ... (8)

9. It is a method of driving the display device.
The display device is
With multiple light sources lined up in at least one direction,
A display unit having a display area provided with a plurality of pixels and outputting an image illuminated by light from the plurality of light sources.
A control unit that controls the operation of the light source based on the display output content of the display unit is provided.
The display area is divided into a plurality of partial areas associated with each of the plurality of light sources.
Each of the partial regions is illuminated by a first region illuminated by light from a first light source associated with the partial region, and by light from the first light source and a second light source adjacent to the first light source. It has two areas and
The driving method is
The first light source is based on the necessity of the light from the first light source in the first region and whether or not the light from the second light source can obtain the light required for the display output in the second region. Has to control the operation.

10. When the light from the first light source is unnecessary in the first region and the light required for the display output can be obtained from the light from the second light source in the second region, the first light source is turned off. do,
9. The method of driving the display device described in 1.

11. 9. The operation of the second light source is controlled based on the comparison result between the brightness of light required in the second region and a predetermined threshold value. Or 10. The method of driving the display device described in 1.

12. The brightness of the light required in the second region is L2_lq, the brightness of the light required in the first region associated with the second light source is L1_cq, and L1_cq is multiplied by the first coefficient of 0 or more and 1 or less. When the first threshold value is T1 and the luminance of the first region due to the lighting of the second light source is BL1, when the equation (1) is established, the luminance is obtained by the equation (2). Turn on the light source 11. The method of driving the display device described in 1.
L2_lq ≧ T1 ... (1)
BL1 = L1_cq × (L2_lq / T1) ... (2)

13. When the second threshold value obtained by multiplying L1_cq by 0 or more and 1 or less and a second coefficient larger than the first coefficient is T2, when the equation (3) holds, the luminance obtained by the equation (2) 12. Turn on the second light source so that it becomes. The method of driving the display device described in 1.
L2_lq≤T2 ... (3)

14. When the maximum brightness of the second light source is T3 and the formula (4) holds for the brightness obtained by the formula (2), the brightness is updated by the formula (5). Or 13. The method of driving the display device described in 1.
BL1> T3 ... (4)
BL1 = T3 ... (5)

15. When the second coefficient is Coef2 and the brightness of the second region due to the lighting of the first light source is BL2, the control unit lights the first light source so as to have the brightness obtained by the equation (6). Let 13. The method of driving the display device described in 1.
BL2 = L2_lq- (T3 x Coef2) ... (6)

16. When the maximum luminance of the second light source is T3 and the luminance of the second region due to the lighting of the first light source is BL2, when the equation (4) holds for the luminance obtained by the equation (2), the said person concerned. 12. The first light source is turned on so that the luminance is updated by the equation (7) and the luminance is obtained by the equation (8). Or 13. The method of driving the display device described in 1.
BL1> T3 ... (4)
BL1 = L1_cq ... (7)
BL2 = L2_lq ... (8)

1 Display device 2 Display unit 3 Drive element 6 Light source unit 6a Light source 100 Control unit 101 Display control unit 102 Light source control unit 76a Black matrix 76b Opening C 1st area COM Common electrode FG Windshield M Mirror Pix Pixel Vpix Sub-pixel XA, XB, YA, YB, XAYA, XBYA, XAYB, XBYB second region

Claims (2)

Multiple light sources arranged in a matrix along the first and second directions orthogonal to each other,
A display unit having a display area provided with a plurality of pixels and outputting an image illuminated by light from the plurality of light sources.
A control unit that controls the operation of the light source based on the display output content of the display unit is provided.
The display area is divided into a plurality of partial areas associated with each of the plurality of light sources.
The partial regions are the rectangular first region illuminated by the light from the first light source associated with the partial region, and the light from the first light source and the second light source adjacent to the first light source, respectively. It has a second area to be illuminated and
The second light source includes two light sources facing the first direction with the first light source interposed therebetween and two light sources facing the second direction with the first light source interposed therebetween.
The second region includes two third regions along each of two opposite sides in the first direction across the first region, the two opposite sides in the second direction across the first region Includes two fourth regions along each and a fifth region located outside the four corners of the rectangular first region.
The control unit is based on whether or not the light from the first light source in the first region is necessary and whether or not the light from the second light source in the second region can obtain the light required for display output. By controlling the operation of the first light source,
In the fifth region, the light from the second light source determines whether or not the light required for display output can be obtained. In the third region, the light from the second light source obtains the light required for display output. It is performed as a determination as to whether or not the light required for the display output can be obtained by the light from the second light source in the fourth region .
When there is a pixel that requires light in the first region, the first light source is turned on.
When the light from the first light source is unnecessary in the first region and the light from the second light source cannot obtain the light required for the display output in the second region, the first light source is used. Lights up and
When the light from the first light source is unnecessary in the first region and the light required for the display output can be obtained from the light from the second light source in the second region, the first light source is turned off. a display device for. Multiple light sources arranged in a matrix along the first and second directions orthogonal to each other,
A display unit having a display area provided with a plurality of pixels and outputting an image illuminated by light from the plurality of light sources.
A method of driving a display device including a control unit that controls the operation of the light source based on the display output content of the display unit.
The display area is divided into a plurality of partial areas associated with each of the plurality of light sources.
The partial regions are the rectangular first region illuminated by the light from the first light source associated with the partial region, and the light from the first light source and the second light source adjacent to the first light source, respectively. It has a second area to be illuminated and
The second light source includes two light sources facing the first direction with the first light source interposed therebetween and two light sources facing the second direction with the first light source interposed therebetween.
The second region includes two third regions along each of two opposite sides in the first direction across the first region, the two opposite sides in the second direction across the first region Includes two fourth regions along each and a fifth region located outside the four corners of the rectangular first region.
The first light source is based on the necessity of the light from the first light source in the first region and whether or not the light from the second light source can obtain the light required for the display output in the second region. Control the movement,
In the fifth region, the light from the second light source determines whether or not the light required for display output can be obtained. In the third region, the light from the second light source obtains the light required for display output. It is performed as a determination as to whether or not the light required for the display output can be obtained by the light from the second light source in the fourth region .
When there is a pixel that requires light in the first region, the first light source is turned on.
When the light from the first light source is unnecessary in the first region and the light from the second light source cannot obtain the light required for the display output in the second region, the first light source is used. Lights up and
When the light from the first light source is unnecessary in the first region and the light required for the display output can be obtained from the light from the second light source in the second region, the first light source is turned off. How to drive the display device.

Images