JP6479401B2 - Display device, control method of display device, and control program - Google Patents

Description

  The present invention relates to a display device that adjusts the brightness of a light source according to an image.

  In display devices such as mobile phones and smartphones in recent years, current consumption has increased significantly with the expansion of functions. Therefore, there is an influence such as shortening of continuous use time. On the other hand, there are techniques for reducing power consumption by raising the gradation of an image by image processing and lowering the luminance of the backlight accordingly (Patent Documents 1 and 2).

Unexamined-Japanese-Patent No. 2010-139678 (June 24, 2010 publication) JP-A-2014-52494 (released on March 20, 2014)

  The increase in gradation of the image due to the image processing and the decrease in luminance of the backlight are basically performed at the same timing. At that time, flicker may be visually recognized if each is changed to the target value at one time. Therefore, a display device using this technology generally changes the gradation of the image and the luminance of the backlight gradually and gradually to the respective target values over several frames.

  However, in the case where a black image is displayed for a period of time following a bright image and then a bright image is displayed again, the above-described technique is disadvantageous. In this case, in the above technology, the luminance of the backlight is gradually decreased from the time when the black image is displayed, and the gradation of the image is increased. Finally, in the period in which the black image is displayed, the brightness of the backlight is significantly reduced to match the black image. Thereafter, when display of a bright image starts, the brightness of the backlight is gradually increased, and the gradation of the image is reduced. As a result, since the brightness of the backlight is significantly reduced according to the black image, when a bright image is displayed thereafter, the period until the brightness of the backlight gradually increases to the target value is It looks darker than the image. In addition, since the brightness of the backlight increases stepwise after the brightness of the backlight decreases significantly, flicker is visually recognized.

  An object of the present invention is to provide a display device with improved display quality.

  A display device according to one aspect of the present invention includes a light source, a display panel that controls an amount of passing light from the light source to display an image, brightness of the light source, and gradation of the image. The image processing apparatus further includes a correction unit that corrects in the opposite direction and an image determination unit that determines whether the image is a black image or a non-black image, and the correction unit includes a plurality of continuous non-black image frames. When the luminance of the light source and the correction strength of the gradation of the image are gradually changed to their respective target values over a plurality of frames, and a black image frame and a non-black image frame are continuous The luminance of the light source and the correction intensity are changed to their respective target values in one frame.

  A control method of a display device according to an aspect of the present invention is a control method of a display device including a light source and a display panel that controls an amount of passing of light from the light source to display an image. The method includes an image determination step of determining whether the image is a black image or a non-black image, and a correction step of correcting the brightness of the light source and the gradation of the image in opposite directions with respect to brightness. In the above, when a plurality of non-black image frames are continuous, the luminance of the light source and the correction intensity of the gradation of the image are stepwise changed to their respective target values over When the frame and the frame of the non-black image are continuous, the luminance of the light source and the correction intensity are changed to their respective target values in one frame.

  According to one aspect of the present invention, it is possible to achieve both reduction in current consumption and improvement in display quality in the case where a black image and a non-black image are continuous.

FIG. 1 is a block diagram showing a schematic configuration of a display device according to an embodiment of the present invention. It is a figure which shows the processing flow of the correction | amendment in the said display apparatus. It is a timing chart which shows the example of amendment of the brightness of the back light in the reference example, and the gradation of a picture. It is a timing chart which shows the example of amendment of the luminosity of the back light in the operation example of one embodiment of the present invention, and the gradation of a picture.

Embodiment 1
(Configuration of display device)
FIG. 1 is a block diagram showing a schematic configuration of a display device 1 according to the present embodiment. The display device 1 includes a control device 2, a display driver 3, a liquid crystal display panel 4 (display panel), and a backlight 5 (light source). In the following description, although the maximum gradation is 255 and the minimum gradation is 0, the present invention is not limited to this.

  Display data is input to the control device 2. The control device 2 outputs control signals for controlling each of the display driver 3 and the backlight 5 based on the input display data. Further, the control device 2 outputs display data to the display driver 3. The display driver 3 converts display data into an analog voltage signal and supplies the voltage signal to the liquid crystal display panel 4.

  The liquid crystal display panel 4 includes a plurality of pixels having liquid crystal elements. The liquid crystal display panel 4 changes the transmittance of the pixel in accordance with the analog voltage signal. The backlight 5 is a light source for illuminating the liquid crystal display panel 4. The liquid crystal display panel 4 displays an image by transmitting (passing) the light from the backlight 5 according to the transmittance of the pixel.

  The luminance of the pixel visually recognized by the user is determined by the product of the luminance of the backlight 5 and the transmittance of the pixel of the liquid crystal display panel 4. For example, if the gradation of the entire image is increased so as to double the transmittance of all the pixels at the same time as reducing the luminance of the backlight 5 in half, the luminance visually recognized by the user does not change.

  The control device 2 includes a black image detection unit 11 (image determination unit), an image analysis unit 12 (correction unit), an image processing unit 13 (correction unit), and a backlight control unit 14 (correction unit). The display data is input to the black image detection unit 11, the image analysis unit 12, and the image processing unit 13. Here, the display data represents an image of one frame.

  The black image detection unit 11 determines whether the image indicated by the display data is a black image or a normal image (non-black image). Further, the black image detection unit 11 refers to the determination result of the image of the immediately preceding frame, and determines whether the black image and the normal image are continuous. The black image detection unit 11 outputs these determination results to the image analysis unit 12. The black image detection unit 11 may determine that the image is a black image, for example, when the pixel values (tones) of all the pixels of the image indicated by the display data are values indicating black. Alternatively, the black image detection unit 11 may determine that the image is a black image, when the proportion of pixels showing black in the image is equal to or greater than the first threshold. Alternatively, the black image detection unit 11 may determine that the image is a black image when the ratio of (dark) pixels whose pixel value is less than a predetermined value in the image is equal to or greater than a first threshold. Here, that the pixel value is high indicates that the pixel is bright. Alternatively, the black image detection unit 11 may determine that the image is a black image when the maximum pixel value in the image is less than a predetermined value. A black image is an image that is perceived as almost entirely black. In other cases, the black image detection unit 11 determines that the image is not a black image. The first threshold and the predetermined value may be determined in consideration of noise and the like that can be superimposed on an image of display data.

  The image analysis unit 12 determines the target value of the brightness BL of the backlight 5 and the correction strength C of the gradation of the image according to the contrast of the image of the display data. The image analysis unit 12 generates a histogram regarding pixel values (tones) in the image. The image analysis unit 12 determines a target value of the luminance BL of the backlight 5 for displaying the image indicated by the display data and a target value of the correction strength C of the gradation of the image based on the generated histogram. .

  Specifically, if the image is a bright image in which the image includes pixels with the maximum gradation (gradation 255), the image analysis unit 12 maintains the target value of the luminance BL of the backlight 5 high, and the image floor A target value of the correction strength C of the key is determined as C (0). For example, when the correction strength is C (0), the gradation of the image is not increased (changed). On the other hand, as the image is darker, the image analysis unit 12 lowers the target value of the luminance BL of the backlight 5 and increases the target value of the correction strength C of the gradation of the image. The target value of the brightness BL of the backlight 5 and the target value of the correction strength C of the gradation of the image have a correlation such that the appearance of the displayed image does not greatly change. As the correction strength C is larger, the gradation of the pixel is corrected to be higher (brighter).

  The image analysis unit 12 may determine that the image is a brighter image, for example, as the proportion of pixels whose pixel value is equal to or greater than the second threshold in the image is high. The second threshold may be greater than the first threshold.

  Further, the image analysis unit 12 determines how many frames the luminance BL and the correction strength C are to be changed to their respective target values. When a plurality of frames of a normal image which is not a black image is continuous, the image analysis unit 12 sets this transition period as a plurality of frames. In this case, the luminance BL and the correction strength C change stepwise to the target value over the transient period (multiple frames). The length of the transition period in this case may be a predetermined number of frames, or may be changed according to, for example, the amount of change in the brightness BL or the correction intensity C (the difference between the current value and the target value) . For example, as the change amount of the luminance BL or the correction intensity C is larger, the transition period can be set longer. In addition, an upper limit may be provided to the amount of change of the correction strength C in one frame.

  On the other hand, when the black image and the normal image are continuous, the image analysis unit 12 sets the transition period to one frame. In this case, the luminance BL and the correction strength C change to the target value at one time in one frame. That is, when the normal image is switched to the black image, or when the black image is switched to the normal image, the luminance BL and the correction intensity C change to the target value in one frame.

  For example, in the case of a normal image, the image analysis unit 12 sets the target value of the brightness BL of the backlight 5 in the range of 90% to 20% of the maximum output, and in the case of a black image, the brightness BL is less than 20%. You may set in 0% or more of range.

  The image analysis unit 12 outputs the target value of the brightness BL of the backlight 5 and the transition period to the backlight control unit 14. The image analysis unit 12 outputs the target value and the transition period of the correction strength C of the gradation of the image to the image processing unit 13.

  The backlight control unit 14 generates a control signal for controlling the brightness BL of the backlight 5 based on the target value of the brightness BL of the backlight 5 and the transition period, and outputs the generated control signal to the backlight 5. Output. Specifically, when the transition period is one frame, the backlight control unit 14 performs backlighting so that the brightness BL of the backlight 5 of the next frame (the frame in which the corresponding image is displayed) becomes the target value. Control 5

  When the transition period is a plurality of frames, the backlight control unit 14 performs backlighting in each frame so that the brightness BL of the backlight 5 changes stepwise (or continuously) over the plurality of frames. Control 5 Thereby, the brightness BL of the backlight 5 can be changed gently.

  The image processing unit 13 corrects the gradation of the image of the display data based on the target value of the correction strength C of the gradation of the image and the transition period. The image processing unit 13 outputs the data of the corrected image to the display driver 3. Specifically, when the transition period is one frame, the image processing unit 13 corrects the gradation of the image of the next frame according to the target value of the correction strength C. As the correction strength C is larger, the gradation of pixels in the entire image is increased.

  When the transition period is a plurality of frames, the image processing unit 13 determines the correction intensity C in each frame so that the correction intensity C gradually (continuously) changes to the target value over the plurality of frames. The image processing unit 13 corrects the gradation of the image of each frame in accordance with the determined correction strength C.

  Here, the gradation and the transmittance (brightness) are generally not in proportion. The relationship between the gradation and the transmittance is determined by a predetermined γ correction or the like so as to obtain a desired γ characteristic. Therefore, the brightness BL of the backlight 5 and the transmittance of the gradation corrected image in the liquid crystal display panel 4 are changed so as to be inversely proportional to each other. For example, when the luminance BL of the backlight 5 is halved, the gradation of the entire image is changed so that the transmittance of each pixel is doubled. By this, it is possible to display an image without significantly changing the appearance of the image before or after the brightness BL of the backlight 5 and the gradation of the image are corrected, or in a transition period.

(Processing flow of correction)
FIG. 2 is a diagram showing a processing flow of correction in the display device 1. The control device 2 inputs display data to the black image detection unit 11, the image analysis unit 12, and the image processing unit 13 (S1).

  The black image detection unit 11 determines whether a switch from a normal image to a black image or a switch from a black image to a normal image is detected in consecutive frames (S2).

  When switching between the normal image and the black image is not detected (No in S2), the image analysis unit 12 sets the target value of the brightness BL of the backlight 5 and the correction intensity C of the gradation of the image according to the image of the display data. A target value is determined (S3). The image processing unit 13 corrects (image processing) the gradation of the image of the display data with a correction intensity that gradually approaches the target value of the correction intensity C (S4). The backlight control unit 14 determines the brightness BL of the backlight 5 in the frame in which the corrected image is displayed such that the brightness BL of the backlight 5 gradually approaches the target value of the brightness BL over a plurality of frames. To do (S5).

  The display driver 3 causes the liquid crystal display panel 4 to display the corrected image (S6). The backlight control unit 14 corrects (changes) the brightness BL of the backlight 5 to the determined brightness BL in accordance with the timing (frame) at which the corrected image is displayed on the liquid crystal display panel 4 (S7) ).

  When switching between the normal image and the black image is detected (Yes in S2), the image analysis unit 12 corrects the target value of the brightness BL of the backlight 5 and the correction intensity C of the gradation of the image according to the image of the display data. The target value of is determined (S13). The image processing unit 13 corrects (tones) the gradation of the image of the display data with the correction strength C of the target value (image processing). The backlight control unit 14 targets the brightness BL of the backlight 5 in the frame in which the image is displayed so that the brightness BL of the backlight 5 becomes the target value of the brightness BL in one frame. The value is determined to be the same as the value (S15). Thereafter, the process shifts to S6.

(Reference example)
FIG. 3 is a timing chart showing an example of the correction of the luminance of the backlight and the gradation of the image in the reference example. In the reference example, when switching from the normal image to the black image or the reverse, stepwise correction is performed over a plurality of frames as in the case where the normal image continues.

  In the figure, “display data” indicates display data of each frame input to the control device 2. Since the input display data is analyzed by the image analysis unit 12, as indicated by an arrow in the drawing, the image analysis result is output after the display data is input. In the upper part of the figure, the brightness BL of the backlight and the correction strength C of the gradation of the image are shown. After the image analysis result is output, the tone of the image is corrected, and then the image is displayed. Therefore, although there is a time lag between the output of the image analysis result and the timing of changing the brightness BL of the backlight 5 or the like, it is omitted here.

  The image of the display data D1 is a bright image. The images of a plurality of frames of D1 may not be the same image, and D1 indicates that the display data of each frame is an image of the same degree of brightness. At this time, the target value of the luminance BL of the backlight 5 is BL (2), and the target value of the correction strength C of the gradation of the image is C (0). Therefore, while the bright image is displayed (until time T (1)), the brightness BL of the backlight 5 is maintained at BL (2) and the correction intensity C of the image gradation is maintained at C (0) Be done.

  The image of the display data D2 is not a black image but a dark image. At this time, the target value of the luminance BL of the backlight 5 is BL (1) lower than BL (2), and the target value of the correction strength C of the gradation of the image is C (1) larger than C (0). Become. Here, the control device 2 moves the luminance BL and the correction intensity C toward their respective target values over five frames from time T (1) at which display of the image of the display data D2 starts to time T (2). I will change in stages. At time T (2), the luminance BL and the correction intensity C reach their respective target values BL (1) and C (1). After that, as long as the degree of brightness of the image is changed and the target value is not changed (time T (3)), the brightness BL and the correction intensity C are maintained.

  The image of display data D3 is brighter than the image of display data D2 and darker than the image of D1. At this time, the target value of the luminance BL of the backlight 5 becomes a value between BL (2) and BL (1), and the target value of the correction strength C of the gradation of the image is C (0) and C It becomes the value between (1). Since the difference to the target value is smaller than the previous value, the control device 2 takes two frames from the time T (3) to the time T (4) at which the display of the image of the display data D2 is started. Is gradually changed toward each target value.

  From time T (5), the luminance BL of the backlight 5 falls again over a plurality of frames, and at the same time the correction strength C of the gradation of the image rises. By changing the image to the bright image of the display data D5 in the middle of the transition to the target value, the target values of the brightness BL and the correction strength C are changed to BL (2) and C (0) after time T (6). Ru. When the target value is changed, the brightness BL and the correction strength C are (stepwise) changed from the current brightness BL and the correction strength C toward the respective target values.

  From time T (7) to time T (8), a bright image of the display data D5 is displayed, the brightness BL of the backlight 5 is BL (2), and the correction strength C of the image gradation is C (0). is there.

  The image of the display data D6 is a black image. At this time, the target value of the luminance BL of the backlight 5 is BL (0) as the lower limit, and the target value of the correction strength C of the gradation of the image is C (2) as the upper limit. In the reference example, even when switching from the normal image to the black image as described above, the brightness BL and the correction intensity C are gradually changed (from a plurality of frames) from time T (8) to time T (9).

  The image of the display data D7 is a bright image (normal image). At this time, the target value of the luminance BL of the backlight 5 is BL (2), and the target value of the correction strength C of the gradation of the image is C (0). In the reference example, even when switching from the black image to the normal image in this manner, the luminance BL and the correction intensity C are gradually changed (from a plurality of frames) from time T (10) to time T (11).

  When the normal image is switched to the black image, from time T (8) to time T (9), although the image to be displayed is a black image, the backlight is lit with luminance BL more than necessary. In addition, from the time T (9) to the time T (10), the brightness BL of the backlight is significantly reduced according to the black image. Thereafter, when the black image is switched to the normal image, the period until the luminance BL of the backlight gradually increases to the target value (time T (10) to time T (11)) is visually perceived darker than the original image I will. In addition, since the brightness of the backlight increases stepwise after the brightness of the backlight decreases significantly, flicker is visually recognized in this period.

(Operation example)
FIG. 4 is a timing chart showing an example of the correction of the luminance of the backlight and the gradation of the image in the operation example of the present embodiment. In this operation example, when switching from the normal image to the black image or vice versa, the brightness BL of the backlight 5 and the correction intensity C of the image gradation are immediately changed to the respective target values.

  The input display data D1 to D7 are the same as in the case shown in FIG. The operation up to time T (8) corresponding to the display data D1 to D5 in this operation example is the same as that of the reference example, and thus the detailed description will be omitted. Also in this operation example, the brightness BL of the backlight 5 and the correction intensity C of the gradation of the image are corrected in the opposite directions (complementarily) with respect to the brightness. That is, the luminance BL and the correction intensity C are corrected so as to compensate for the change in the luminance BL of the backlight 5 by the change in the gradation of the image. Therefore, in the period (time T (1) to time T (8)) in which the normal image continues, the brightness BL of the backlight 5 and the correction intensity C of the gradation of the image are set according to the image. It changes gradually over several frames toward the target value of. As described above, the current consumption can be reduced by appropriately reducing the luminance BL of the backlight 5.

  Before and after time T (8), the normal image and the black image are continuous. In addition, black images are continuous from time T (8) to time T (10). Then, before and after time T (10), the black image and the normal image are continuous.

  When switching from the normal image to the black image of the display data D6, the target value of the brightness BL of the backlight 5 becomes the lower limit BL (0), and the target value of the correction strength C of the image gradation is the upper limit C ( It becomes 2). In this operation example, when switching from the normal image to the black image, the brightness BL of the backlight 5 and the correction intensity C of the gradation of the image are immediately (in one frame from time T (8) to time T (9 ')). It is changed to each target value.

  As a result, it is possible to reduce unnecessary current of the backlight 5 in a period from time T (8) to time T (10) displaying a black image. Further, since it is a black image to be displayed, flicker is not visually recognized.

  When the black image is switched to the normal image of the display data D7, the target value of the brightness BL of the backlight 5 is BL (2), and the target value of the correction strength C of the gradation of the image is C (0). In this operation example, when switching from a black image to a normal image, the brightness BL of the backlight 5 and the correction intensity C of the gradation of the image are immediately (in one frame from time T (10) to time T (11 ')). It is changed to each target value.

  Thus, when displaying a bright image immediately after the black image, the control device 2 immediately raises the brightness BL of the backlight 5. Therefore, the image can be appropriately displayed without the bright image being perceived as darker than originally. Further, in this operation example, immediately after the period in which the black image is displayed, the display of the bright image is started with the brightness BL of the backlight 5 which has risen to the target value. Therefore, in the reference example, flicker caused by largely changing the brightness BL of the backlight 5 stepwise in the display period of a bright image does not occur in this operation example. As described above, the display quality of the display device 1 can be improved by making the correction process when the black image is inserted into the normal image different from the correction process when the normal image is continuous.

  Although not shown, a black image may be inserted in a transition period such as between time T (1) and time T (2) or between time T (3) and time T (4). , The same process is performed. That is, when display of a black image is started, the brightness BL of the backlight 5 immediately becomes (lower limit) BL (0) (in one frame), and the correction strength C of the gradation of the image C (2) of the upper limit become. After that, when switching from a black image to a normal image, the brightness BL immediately (in one frame) becomes a target value (for example, BL (1)) matched to the normal image to be displayed, and the correction intensity C is a normal image displayed It becomes a target value (for example, C (1)) adjusted to

[Modification]
Such a display device 1 is, for example, a monitor mounted on a mobile terminal such as a smartphone terminal, a mobile phone, a tablet terminal, an electronic book reader, or a PDA (Personal Digital Assistant), or a laptop personal computer It may be used for a monitor of the type, a television receiver or the like.

  The present invention is not limited to the liquid crystal display device, and can be applied to a display device including a light source and a display panel that displays an image by controlling the passing amount of light from the light source. For example, the display device according to one embodiment of the present invention can be realized as a micro electro mechanical systems (MEMS) display. The MEMS display includes, for example, an RGB light source and a display panel, and adjusts the amount of light passing through each pixel by opening and closing the mechanical shutter provided for each pixel of the display panel at high speed. This makes it possible to display multiple colors and multiple gradations. That is, the transmittances of the backlight and the liquid crystal pixel in the liquid crystal display correspond to the ratio of the light source and the shutter opening in the MEMS display (the ratio of the light passing through the shutter), respectively. Therefore, also in the MEMS display, the luminance of the light source and the gradation of the image can be corrected in the opposite direction with respect to the brightness by decreasing the luminance of the light source and prolonging the shutter open period. Therefore, the processing of the control device 2 of the present invention can be applied to a MEMS display.

  The process may be performed as in the above-described operation example only when the normal image is switched to the black image. Further, processing may be performed as in the above-described operation example only when switching from a black image to a normal image.

[Example of software implementation]
At least a part of the control block (in particular, the black image detection unit 11, the image analysis unit 12, the image processing unit 13 and the backlight control unit 14) of the control device 2 is a logic circuit (IC chip) or the like It may be realized by hardware) or may be realized by software using a CPU (Central Processing Unit).

  In the latter case, the control device 2 is a CPU that executes instructions of a program that is software that realizes each function, a ROM (Read Only Memory) in which the program and various data are readably recorded by a computer (or CPU) or A storage device (these are referred to as a "recording medium"), a RAM (Random Access Memory) for developing the program, and the like are provided. The object of the present invention is achieved by the computer (or CPU) reading the program from the recording medium and executing the program. As the recording medium, a “non-transitory tangible medium”, for example, a tape, a disk, a card, a semiconductor memory, a programmable logic circuit or the like can be used. The program may be supplied to the computer via any transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program. The present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[Summary]
A display device according to aspect 1 of the present invention includes a light source (backlight 5), a display panel (liquid crystal display panel 4) that displays an image by controlling the passing amount of light from the light source, luminance of the light source, A correction unit (image analysis unit 12, image processing unit 13, backlight control unit 14) that corrects the gradation of the image in the opposite direction with respect to brightness, and the image is a black image or a non-black image (image And an image determination unit (black image detection unit 11) for determining whether the image is a normal image), the correction unit, when there are a plurality of consecutive non-black image frames, the luminance of the light source and the floor of the image The tone correction intensity is changed stepwise to each target value over a plurality of frames, and when the black image frame and the non-black image frame are continuous, the luminance of the light source and the correction intensity are calculated. Up to each target value in one frame Make.

  According to the above configuration, the current consumption can be reduced by correcting the brightness of the light source and the gradation of the image in a complementary manner. In addition, when a plurality of non-black images are continuous, the display device gradually changes the luminance of the light source and the correction intensity of the gradation of the image to respective target values in a plurality of frames. By this, it is possible to prevent the flicker from being visually recognized. Further, when the black image and the non-black image are continuous, the display device displays the non-black image by changing the luminance of the light source and the correction intensity to their respective target values in one frame. Display quality can be improved. Therefore, it is possible to achieve both the reduction of the current consumption and the improvement of the display quality when the black image and the non-black image are continuous.

  In the display device according to aspect 2 of the present invention, in the above aspect 1, when the non-black image continues after the black image, the correction unit raises the luminance of the light source to its target value in one frame, The correction strength may be reduced to its target value in one frame.

  When a non-black image follows a black image, the non-black image appears darker during the transition period if the luminance and the gradation correction intensity are changed stepwise. According to the above configuration, since the luminance and the correction intensity are immediately changed in one frame in such a case, it is possible to display a non-black image with appropriate brightness.

  In the display device according to aspect 3 of the present invention, in the aspect 1 or 2, when the black image follows the non-black image, the correction unit reduces the luminance of the light source to its target value in one frame. The correction strength may be raised to its target value in one frame.

  According to the above configuration, wasteful current consumption of the light source can be reduced in a period in which a black image is displayed.

  In the display device according to aspect 4 of the present invention, in the above aspects 1 to 3, the target value of the luminance of the light source when the image is a black image is the luminance of the light source when the image is a non-black image It may be lower than the target value of.

  Since the black image is an image which is perceived almost entirely by the user as black, the luminance of the light source can be further reduced to reduce current consumption.

  In the display device according to aspect 5 of the present invention, in the above aspects 1 to 4, the image determining unit determines that the image is a black image when the image is a black image not displaying a graphic and a video. The configuration may be

  The display device according to each aspect of the present invention may be realized by a computer. In this case, the computer is operated as each unit (limited to software elements) included in the display device, and the display device is operated by the computer. A control program of a display device to be realized and a computer readable recording medium recording the same also fall within the scope of the present invention.

  A control method of a display device according to a sixth aspect of the present invention is a control method of a display device including a light source and a display panel that controls an amount of passing of light from the light source to display an image, and the image is The method includes an image determination step of determining whether the image is a black image or a non-black image, and a correction step of correcting the brightness of the light source and the gradation of the image in opposite directions with respect to brightness. In the above, when a plurality of non-black image frames are continuous, the luminance of the light source and the correction intensity of the gradation of the image are stepwise changed to their respective target values over When the frame and the frame of the non-black image are continuous, the luminance of the light source and the correction intensity are changed to their respective target values in one frame.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

  The present invention can be used for a display device.

1 Display Device 2 Control Device 3 Display Driver 4 Liquid Crystal Display Panel (Display Panel)
5 Backlight (light source)
11 Black image detection unit (image determination unit)
12 Image analysis unit (correction unit)
13 Image processing unit (correction unit)
14 Backlight control unit (correction unit)

Claims (5)

Light source,
A display panel that displays an image by controlling the passing amount of light from the light source;
A correction unit that corrects the luminance of the light source and the gradation of display data in opposite directions with respect to brightness;
And a determining image determining unit for determining the display data indicates a non-black image or shows a black image,
The correction unit is
When a plurality of non-black image frames are continuous, the luminance of the light source and the correction intensity of the gradation of the display data are stepwise changed to their respective target values over a plurality of frames,
A display device characterized in that when the frame of a black image and the frame of a non-black image are continuous, the luminance of the light source and the correction intensity are changed to their respective target values in one frame.   The correction unit is characterized in that, when a non-black image follows a black image, the luminance of the light source is increased to its target value in one frame, and the correction intensity is decreased to its target value in one frame. The display device according to claim 1.   The correction unit is characterized in that when the non-black image is followed by the black image, the brightness of the light source is decreased to its target value in one frame, and the correction intensity is increased to its target value in one frame. The display device according to claim 1 or 2.   It is a control program for functioning a computer as a display as described in any one of Claim 1 to 3, Comprising: The control program for functioning a computer as said each part. A control method of a display device comprising: a light source; and a display panel that displays an image by controlling a passing amount of light from the light source,
An image determination step of determining whether the display data indicates a non-black image or shows a black image,
Correcting the brightness of the light source and the gray level of the display data in opposite directions with respect to brightness;
In the above correction step,
When a plurality of non-black image frames are continuous, the luminance of the light source and the correction intensity of the gradation of the display data are stepwise changed to their respective target values over a plurality of frames,
A control method of a display device, wherein the luminance of the light source and the correction intensity are changed to their respective target values in one frame when a black image frame and a non-black image frame are continuous.

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