JP2021135408A - Display control device and display device - Google Patents

Abstract

To suppress image sticking and color shift due to a deviation of correction in pixels whose cumulative light emission times become equal to or greater than a prescribed time.SOLUTION: A display control unit 3 sets a pixel with the longest cumulative light emission time in a pixel group made of self-luminous elements constituting a display panel 2 as a high frequency pixel, and sets a residual pixel group different from the high frequency pixel in the pixel group as a low frequency pixel group. The display control unit 3 includes a light emission adjustment part 35, and causes the display panel 2 to display a corrected video in which the high frequency pixel is turned off and only the low frequency pixel group is turned on together with the normal video display so as to prevent a user from visually recognizing the corrected video. With this, a difference in the cumulative light emission times between the low frequency pixel group and the high frequency pixel becomes small. Even if a deviation of correction occurs, since the low frequency pixel group and the high frequency pixel have the same level of deviations, image sticking and color shift due to the deviation of correction is suppressed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a display control device for executing drive control of a display panel in which each pixel is composed of a self-luminous element, and a display device including the display control device.

In recent years, in the field of display devices, many of them use precise graphics, and among them, display devices having a display panel in which pixels are composed of self-luminous elements can improve the display quality, and are therefore regarded as promising. There is. Examples of this type of display panel include an organic light emitting diode (OLED) panel.

A self-luminous element such as an OLED has a characteristic that the light emitting characteristic deteriorates as the cumulative light emitting time increases, and the brightness decreases even if the current value is the same. When various images are displayed on a display panel in which each pixel is composed of a self-luminous element, the cumulative light emission time of each pixel varies, which causes a variation in the degree of deterioration of characteristics, that is, a variation in the amount of deterioration. In this type of display panel, a so-called burn-in occurs in which the pixel group having a large amount of deterioration appears to be burned due to the decrease in brightness of the pixel group having a large amount of deterioration as compared with other pixels.

Examples of the display device capable of suppressing the deterioration of the visibility of the image due to such burning include those described in Patent Document 1. The display device described in Patent Document 1 includes a display panel in which each pixel is composed of an OLED, calculates the cumulative light emission time for each pixel, and calculates a correction coefficient according to the deterioration characteristic of the cumulative light emission time of the OLED for each pixel. It is a configuration that multiplies the input data. As a result, each pixel emits light with an amount of current that compensates for the decrease in brightness due to the deterioration characteristic of the OLED, and seizure is suppressed.

Japanese Patent No. 3933485

As the total usage time increases, the display panel has a pixel having a short cumulative light emission time and a pixel having a long cumulative light emission time. When performing drive control for suppressing seizure in such a state, for example, a correction that reduces the amount of current in a pixel having a short cumulative emission time and increases the amount of current in a pixel having a long cumulative emission time is performed between these pixels. Reduce the brightness difference.

However, for pixels whose cumulative light emission time is equal to or longer than a predetermined value, that is, the amount of deterioration is equal to or longer than a predetermined value, the change in the amount of current due to the correction becomes larger than that at the initial stage, and the correction tends to be misaligned. In addition, when the pixel group constituting the display panel has a cumulative light emission time of a predetermined time or longer, a correction deviation occurs in each of the pixels having a relatively short cumulative light emission time and the pixels having a long cumulative light emission time, thereby suppressing seizure. Accuracy can be reduced. Further, when the correction shift occurs, the brightness balance of each emission color is lost in each pixel composed of the sub-pixels of a plurality of different emission colors, and the color shift may occur.

In view of the above points, it is an object of the present invention to suppress seizure and color deviation caused by correction deviation in pixels having a cumulative light emission time of a predetermined time or longer in a display panel including pixels made of self-luminous elements. And.

In order to achieve the above object, the display control device according to claim 1 is a display control device that executes display control of a display panel (2) including a plurality of pixels composed of self-luminous elements, and is cumulative for each pixel. A storage unit (31) that stores the light emission time, the pixel having the longest cumulative light emission time among the plurality of pixels is defined as a high-frequency pixel, and a group consisting of pixels different from the high-frequency pixel among the plurality of pixels is a low-frequency pixel group. A light emission adjusting unit (35) that generates a video signal that increases the light emission frequency of the low-frequency pixel group, and a signal output unit (36) that outputs the video signal generated by the light emission adjusting unit to the display panel. The display control unit (3) is provided.

According to this, it is a display control device that controls the display of a display panel including a plurality of pixels composed of self-luminous elements, and is a low-frequency pixel group excluding the high-frequency pixel having the longest cumulative light emission time among the plurality of pixels. It is configured to have a light emission adjusting unit that generates a video signal that increases the light emission frequency of the above. When the light emission frequency of the low-frequency pixel group is increased by the light emission adjusting unit, the difference in the amount of deterioration between the low-frequency pixel group and the high-frequency pixel group becomes small. Therefore, even if a high-frequency pixel having a cumulative light emission time of a predetermined time or longer occurs, the deviation of the correction amount due to the difference in the deterioration amount between the low-frequency pixel group and the high-frequency pixel is reduced, and the display is displayed. It is possible to suppress seizure and color shift in the panel.

The display device according to claim 5 includes a display panel (2) including a plurality of pixels made of a self-luminous element, a storage unit (31) for storing the cumulative light emission time for each pixel, and a plurality of pixels. Light emission that generates a video signal that increases the light emission frequency of the low-frequency pixel group, with the pixel having the longest cumulative light emission time as the high-frequency pixel and the group consisting of pixels different from the high-frequency pixel among the plurality of pixels as the low-frequency pixel group. A display control unit (3) including an adjustment unit (35), a signal output unit (36) that outputs a video signal generated by the light emission adjustment unit to a display panel, and a display control unit (3).

As a result, the display device includes the display control device according to claim 1 and a display panel including a pixel group made of a self-luminous element, and the deviation of correction caused by the pixels whose cumulative light emission time is equal to or longer than a predetermined value is reduced. This is a display device in which seizure and color shift are suppressed.

The reference reference numerals in parentheses attached to each component or the like indicate an example of the correspondence between the component or the like and the specific component or the like described in the embodiment described later.

It is a block diagram which shows the structural example of the display device of 1st Embodiment. It is a figure which shows the relationship example of the relative brightness and the cumulative emission time in a self-luminous element. It is a figure for demonstrating the luminance correction performed in each of a high frequency pixel and a low frequency pixel among the pixel group constituting a display panel. It is a figure which shows the case where the correction amount is deviated in each of a high frequency pixel and a low frequency pixel in the luminance correction shown in FIG. It is a figure for demonstrating the reduction of the deviation of the correction amount between a high frequency pixel and a low frequency pixel by light emission adjustment in a display control unit. It is a figure which shows an example of the insertion of the correction video frame by a light emission adjustment part. It is a flowchart which shows the processing operation example of the light emission adjustment in the display device of 1st Embodiment. It is a flowchart which shows the processing operation example of the correction of a video signal in the display device of 1st Embodiment. It is a block diagram which shows the structural example of the display device of 2nd Embodiment. It is a flowchart which shows the processing operation example of the light emission adjustment in the display device of 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, parts that are the same or equal to each other will be described with the same reference numerals.

(First Embodiment)
The display device 1 according to the first embodiment will be described with reference to FIGS. 1 to 6.

〔composition〕
As shown in FIG. 1, for example, the display device 1 of the present embodiment includes a display panel 2 for displaying various images and a display control unit 3 for executing display control of the display panel 2.

As shown in FIG. 1, for example, the display panel 2 displays various images based on the image signals input via the display control unit 3. The display panel 2 includes an image display area for displaying various images, and a plurality of pixels (hereinafter, referred to as “constituent pixel group”) constituting the image display area are composed of self-luminous elements. The display panel 2 is, for example, an organic light emitting diode (OLED) panel, but the constituent pixel group may be composed of a self-luminous element, and any other self-luminous light such as a micro LED or an inorganic EL (electroluminescence) may be used. It may be composed of elements.

In the OLED panel, for example, a TFT layer having a plurality of thin film transistors (TFTs) and an OLED layer having pixels made up of a plurality of OLED elements are laminated in this order on a flexible substrate. Become. The flexible substrate is made of, for example, a film made of a resin material such as polyimide or an arbitrary material having flexibility such as flexible glass. The TFT layer includes a gate electrode, a gate insulating layer, a semiconductor layer, a source electrode, and a drain electrode, and a plurality of TFTs, which are elements whose current on / off can be controlled by adjusting the voltage of the gate electrode, are formed. Each of the plurality of TFTs is connected to one of a pair of electrodes constituting the plurality of OLED elements in the OLED layer, and is used for driving control of each OLED element. The OLED layer has, for example, a structure in which a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and the like are sequentially laminated between a pair of electrodes, and emits light by applying a voltage. It is provided with a plurality of OLED elements. In an OLED panel, a main pixel composed of OLED elements, for example, having three sub-pixels having different emission colors of red, green, and blue, is orthogonal to one direction in a plan view and orthogonal to the one direction. It is repeatedly arranged along the direction. The "pixel" in the description of the display panel 2 refers to the above-mentioned main pixel composed of a plurality of sub-pixels. In the following description, when simply referred to as a "pixel", it refers to the above-mentioned main pixel.

Further, since the configurations of OLEDs, TFTs, and OLED panels and their materials are known, detailed description thereof will be omitted in the present specification. The configurations of the TFT and the OLED are not limited to the above examples, and any configuration can be adopted.

The display control unit 3 is, for example, an electronic control unit in which a CPU, ROM, RAM, etc. are mounted on a circuit board (not shown), and is referred to as an ECU (abbreviation of Electronic Control Unit). The display control unit 3 is connected to the display panel 2 and other electronic devices (not shown), and is configured to input a video signal from the outside and output the video signal to the display panel 2. The display control unit 3 plays a role as a display control device that reduces the variation in the amount of deterioration in the constituent pixel groups of the display panel 2 and suppresses seizure and color deviation caused by the deviation of the correction amount between the pixels. The details will be described later.

In the present embodiment, the display control unit 3 includes a storage unit 31, a deterioration amount calculation unit 32, a correction amount calculation unit 33, a correction unit 34, a light emission adjustment unit 35, and a signal, for example, as shown in FIG. It includes an output unit 36.

The storage unit 31 is, for example, a storage medium made of a non-volatile memory such as a ROM or a volatile memory such as a RAM, and stores various programs executed by the display control unit 3 and various data used in various programs. As various programs, for example, the deterioration amount calculation unit 32 calculates the deterioration amount of the constituent pixel group, the correction amount calculation unit 33 calculates the correction amount of the driving condition of the constituent pixel group, the light emission adjusting unit 35 calculates the light emission of the constituent pixel group, and the like. Various programs and the like can be mentioned. Examples of various data include cumulative drive time for each constituent pixel of the display panel 2, emission characteristic data for each emission color of the self-luminous element having the same configuration as the constituent pixels, and the like.

The cumulative drive time for each constituent pixel is calculated based on, for example, the history of video signals input to the display control unit 3 from the outside.

The deterioration amount calculation unit 32 calculates the deterioration amount for each of the constituent pixels of the display panel 2, for example, by the deterioration reference curve based on the light emitting characteristics of the self-luminous element and the cumulative light emitting time for each constituent pixel. For example, when the self-luminous element is an OLED, an OLED element having the same configuration as the constituent pixels is manufactured, and the relative brightness with respect to the cumulative light emission time is as shown in FIG. 2 by any method such as constant current drive and brightness measurement. The data of the change of (hereinafter referred to as "reference curve") is acquired in advance. Then, by storing this reference curve in the storage unit 31 and applying the cumulative light emission time to the reference curve, the amount of deterioration can be calculated for each constituent pixel. The deterioration amount calculation unit 32 calculates the deterioration amount for each constituent pixel by, for example, the above method, but the method is not limited to this method, and the deterioration amount may be calculated by another known method.

The term "relative brightness" as used herein means, for example, the brightness when light is emitted at a predetermined current value in an initial state (for example, immediately after production), that is, the initial brightness is set to 1, and the predetermined brightness is set at an arbitrary cumulative light emission time. It means the ratio of the brightness to the initial brightness when the light is emitted at the current value of.

The correction amount calculation unit 33 is required to obtain a current value (gradation value) for maintaining a predetermined brightness by compensating for the decrease in brightness due to deterioration based on the deterioration amount calculated by the deterioration amount calculation unit 32, for example. The correction amount is calculated for each constituent pixel. Regarding the calculation of the correction amount, for example, the luminous efficiency of the constituent pixels is calculated back from the calculated deterioration amount, and the insufficient current amount is calculated from the luminous efficiency with respect to the current amount required to obtain the target brightness. It is done by any method such as calculation.

The correction unit 34, for example, executes the correction of the video signal input from the outside, that is, the correction of the driving conditions of the constituent pixels, based on the correction amount calculated by the correction amount calculation unit 33. The video signal corrected by the correction unit 34 is input to, for example, the signal output unit 36.

The light emission adjusting unit 35 causes a pixel group having a relatively short cumulative light emission time among the constituent pixel groups to emit light in order to suppress seizure and color shift due to variations in the cumulative light emission time and the correction amount in the constituent pixel groups. It plays a role in reducing the variation in cumulative light emission time. In other words, the light emission adjusting unit 35 has a function of selectively increasing the light emission frequency of the low frequency pixel group to reduce the difference in the cumulative light emission time between the low frequency pixel group and the high frequency pixel group.

Here, the seizure and color shift due to the variation in the cumulative light emission time in the constituent pixel group and the suppression thereof will be described with reference to FIGS. 3 to 6.

In FIGS. 3 to 5, the reference curve is indicated by a chain double-dashed line, and the adjustment of the relative luminance in each of the low-frequency pixel and the high-frequency pixel is indicated by an arrow. In FIG. 5, the change curve of the relative brightness of the low-frequency pixels when the light emission adjustment described later is not performed is shown by a broken line, and the change of the relative brightness change curve by the light emission adjustment is shown by a white arrow. In FIG. 6, in order to make it easy to understand the difference in brightness (brightness) in the image of each frame, the off state (black display) is shown in black, the bright area is shown in white in the on state, and the dark area is hatched. Giving. Further, in FIG. 6, the flow of time is indicated by an arrow.

Since various images are displayed on the display panel 2, the history of the brightness and the driving time is different for each constituent pixel, and the cumulative light emission time varies in the constituent pixel group. At this time, the pixel having the highest cumulative light emission time in the constituent pixel group is regarded as a "high frequency pixel", the other pixel is regarded as a "low frequency pixel", and the deterioration of one of the high frequency pixel and the low frequency pixel is performed. Comparing the states, for example, the states shown in FIG. 3 are obtained.

Specifically, for example, at a certain time t, the high-frequency pixels have a lower relative brightness than the deterioration reference curve, whereas the low-frequency pixels have a higher relative brightness than the deterioration reference curve. It becomes. If each pixel is made to emit light in this state, the high-frequency pixel with advanced deterioration has a lower brightness than the low-frequency pixel, and the user perceives it as burning. In addition, when seizure occurs, the high-frequency pixels lose the emission balance of a plurality of sub-pixels having different emission colors, resulting in a color different from the intended color, resulting in a color shift. Can be.

Therefore, in order to suppress such seizure and color shift, control is performed to align the relative luminances of the high-frequency pixels and the low-frequency pixels to predetermined values, as shown by arrows in FIG. 3, for example. As a result, both the high-frequency pixels and the low-frequency pixels have the same relative brightness, so that the decrease in the brightness of the high-frequency pixels with relatively advanced deterioration is less likely to be visually recognized by the user, and seizure is perceived. Can be suppressed.

However, when the cumulative light emission time exceeds a predetermined value, that is, when the deterioration amount exceeds a predetermined value, the correction amount also increases by that amount, and the influence of the deviation in brightness and chromaticity when the deviation in the correction amount occurs becomes large. .. Specifically, the amount of deterioration of the constituent pixels is calculated based on, for example, the luminance characteristics of the self-luminous element having the same configuration as the constituent pixels. However, the constituent pixels may have a film thickness distribution between the pixels due to the influence of tolerances in the manufacturing process, and the degree of deterioration may be different from the reference curve. In this case, there is a difference between the calculated deterioration amount and the actual deterioration amount, and even if a part of the constituent pixel group is corrected by the correction amount based on the calculated deterioration amount, the actual brightness and chromaticity are intended. There is a risk of deviation from what was done. That is, if there is a difference between the calculated deterioration amount and the actual deterioration amount, a deviation (hereinafter, simply referred to as “correction amount deviation”) occurs between the calculated correction amount and the actually required correction amount. As shown in FIG. 4, for example, the deviation of the correction amount can occur in both the low-frequency pixel and the high-frequency pixel, and tends to increase as the cumulative light emission time increases, that is, as the calculated correction amount increases. In this case, in each of the low-frequency pixel and the high-frequency pixel, a deviation between the intended brightness after correction and the actual brightness occurs, and this appears as a brightness difference between the low-frequency pixel and the high-frequency pixel.

In the display device 1 of the present embodiment, in order to suppress the brightness difference and the chromaticity deviation between the low-frequency pixel and the high-frequency pixel due to the variation in the cumulative light emission time and the deviation of the correction amount, the deterioration in the low-frequency pixel is intentionally performed. Controls to bring the degree of progress of the pixel closer to that of high-frequency pixels. Specifically, as shown in FIG. 5, for example, the light emission adjusting unit 35 intentionally accelerates the deterioration of only the low-frequency pixels and reduces the difference in the amount of deterioration between the high-frequency pixels and the low-frequency pixels. Run. As a result, the difference in the amount of deterioration between the constituent pixels is reduced, and even if the amount of correction is deviated, the brightness between the low-frequency pixels and the high-frequency pixels is higher than when the low-frequency pixels are not intentionally deteriorated. The difference can be reduced.

As described above, the light emission adjusting unit 35 executes a control of causing only the low-frequency pixels to emit light and reducing the difference in the amount of deterioration between the low-frequency pixels and the high-frequency pixels. If is perceived by the user, the visibility of the image will be reduced. Therefore, the signal output unit 36, which will be described later, executes control to emit light only the low-frequency pixel group of the display panel 2 based on the video signal generated by the light emission adjusting unit 35 so as not to be perceived by the user.

Hereinafter, for convenience of explanation, the control for emitting light only in the low-frequency pixel group, which is performed to reduce the variation in the cumulative light emission time between the low-frequency pixel group and the high-frequency pixel, and by extension, the variation in the amount of deterioration thereof, is simply "light emission adjustment". May be called.

For example, as shown in FIG. 6, a case where an image composed of a continuous first image frame and a second image frame is displayed on the display panel 2 will be described as an example. Hereinafter, the area displayed by the high-frequency pixels in the video of each frame is referred to as a “high-frequency area”.

In this case, as shown in FIG. 6, the signal output unit 36 turns off the high-frequency pixels between the continuous first video frame and the second video frame, and lights the low-frequency pixel group with a predetermined brightness. Executes the process of inserting the corrected video frame. In other words, the signal output unit 36 generates a frame consisting of the corrected video in which the high frequency region is displayed in black and the other regions are displayed in gray, and the generated corrected video is inserted between the frames of the original video. , Adjusts the light emission of the low frequency pixel group. The light emission adjusting unit 35 executes, for example, setting a low-frequency pixel group and a high-frequency pixel in the constituent pixel group and generating a video signal corresponding to the corrected video frame. As a result, while displaying a predetermined image based on the image signal from the outside, the corrected image is displayed at intervals not perceived by the user, and the image display and the deterioration acceleration of the low-frequency pixel group can be simultaneously executed.

For example, the light emission adjusting unit 35 searches for the pixel having the highest cumulative light emission time for each constituent pixel stored in the storage unit 31, sets the corresponding pixel as a high frequency pixel, and sets the high frequency among the constituent pixel groups. A pixel group different from the pixels is set as a low-frequency pixel group. Then, the light emission adjusting unit 35 generates a video signal corresponding to the corrected video frame in which the gradation value of the set high-frequency pixel is set to zero (displayed in black) and the gradation value of the low-frequency pixel group is set to a predetermined value. , The generated video signal is output to the signal output unit 36.

As shown in FIG. 6, the signal output unit 36 has a corrected video frame between frames in the video presented to the user based on, for example, the video signal corrected by the correction unit 34 and the video signal from the light emission adjusting unit 35. The inserted video signal is generated and output to the display panel 2.

The interval at which the corrected video frame is inserted and the brightness of the low-frequency pixel group may be appropriately changed as long as they are not perceived by the user. Further, in the light emission adjustment by the display control unit 3, the cumulative light emission time of the low frequency pixel group due to the light emission is added, and when a low frequency pixel that reaches the same cumulative light emission time as the high frequency pixel occurs, the said Control to change the low-frequency pixels to black display may be executed. This is preferable from the viewpoint of life characteristics because it is possible to prevent the low-frequency pixels from being excessively deteriorated while reducing the difference in the amount of deterioration between the low-frequency pixel group and the high-frequency pixels.

The above is the basic configuration of the display device 1 of the present embodiment. That is, the display device 1 sets the low-frequency pixel group and the high-frequency pixel based on the cumulative light emission time for each constituent pixel of the display panel 2, and emits light at intervals that the user does not perceive only the low-frequency pixel group, and accumulates them. It is configured to reduce the variation in light emission time.

[Processing operation example]
Next, an example of processing operations in the light emission adjustment and the correction of the driving conditions of the constituent pixels executed by the display device 1 will be described with reference to FIGS. 7 and 8.

First, an example of processing operation in light emission adjustment by the display control unit 3 will be described. The display control unit 3 executes, for example, the control flow shown in FIG. 7 when the power of the display panel 2 is turned on.

In step S101, for example, a video signal is input to the display control unit 3 from an external electronic device.

In the following step S102, the display control unit 3 calculates the cumulative light emission time for each constituent pixel of the display panel 2 based on the video signal input in step S101. The calculated data regarding the cumulative light emission time is stored in, for example, the storage unit 31, and is used in the processing of the next step S103.

Next, in step S103, the light emission adjusting unit 35 sets the pixel having the longest cumulative light emission time among the constituent pixel groups as the high frequency pixel based on the cumulative light emission time data stored in the storage unit 31, for example, and the remaining pixels. Set the group as a low frequency pixel group. After setting the high-frequency pixels, the display control unit 3 advances the process to step S104.

In step S104, the light emission adjusting unit 35 generates a video signal corresponding to a corrected video frame for lighting the low frequency pixel group with a predetermined brightness while turning off the high frequency pixels (displaying in black). Then, the signal output unit 36 outputs the video signal after the light emission adjustment is made to the display panel 2 based on, for example, the video signal from the outside and the video signal corresponding to the corrected video frame generated by the light emission adjusting unit 35. do. The display control unit 3 repeats the control flow of FIG. 7, for example, after the end of step S104.

For example, according to the above control flow, in the display panel 2, only the low-frequency pixel group is made to emit light between the video displays, the variation in the cumulative light emission time and the deterioration amount between the low-frequency pixel group and the high-frequency pixel is reduced, and the correction amount is reduced. Even if the deviation occurs, the deviation of brightness and chromaticity is reduced. This light emission adjustment is executed together with the correction of the driving conditions of the constituent pixels described below.

Subsequently, an example of processing operation in the correction of the driving conditions of the constituent pixels by the display control unit 3 will be described.

In step S110, a video signal is input to the display control unit 3 from, for example, an external electronic device, as in step S101 in the above light emission adjustment.

In the following step S111, the deterioration amount calculation unit 32 calculates the deterioration amount for each constituent pixel based on, for example, the cumulative light emission time for each constituent pixel and the deterioration amount calculation program stored in the storage unit 31. The calculated deterioration amount is temporarily stored in the storage unit 31, for example, and is used in the next step S112.

In step S112, the correction amount calculation unit 33 calculates the correction amount for each constituent pixel based on the deterioration amount and the correction amount calculation program calculated in step S111.

In step S113, the correction unit 34 corrects the video signal based on the correction amount calculated in step S112, for example. The corrected video signal is input to, for example, the signal output unit 36. The display control unit 3 repeats the control flow of FIG. 8 after the end of step S113, for example.

For example, according to the above control flow, in the display panel 2, the amount of current is corrected for each constituent pixel according to the amount of deterioration, and the decrease in brightness due to deterioration is suppressed.

According to the present embodiment, the difference in the cumulative light emission time between the low-frequency pixel group and the high-frequency pixel is small, and the difference in the amount of deterioration between the constituent pixels is reduced. However, it is a display device 1 in which the difference in brightness and the color shift between the low-frequency pixel group and the high-frequency pixel are suppressed.

Further, the display control unit 3 sets the lit pixels in the constituent pixel group as "lighting pixels" and the ratio of the lit pixels to the constituent pixel group as the "lighting rate", and lights the display panel 2 at the time of displaying an image. The brightness control of the lighting pixel according to the rate may be executed.

Specifically, for example, when the lighting rate is high (30% or more, but not limited to), the display control unit 3 may execute a control for lowering the gradation value (luminance) of the lighting pixel. .. As a result, while suppressing the progress of deterioration in the image display of the low-frequency pixel group and the high-frequency pixel, the deterioration promotion of the low-frequency pixel group by the light emission adjustment is relatively accelerated, and the low-frequency pixel group and the high-frequency pixel are combined. It is expected that the accuracy of reducing the difference in the amount of deterioration will be improved.

On the other hand, when the lighting rate is low (less than 30%, but not limited to), the display control unit 3 keeps the gradation value of the pixel having a relatively high gradation value among the lighting pixels and lights it. Control to raise the gradation value of a pixel having a relatively low gradation value among the pixels may be executed. In this case, the deterioration of the pixels having a low gradation value in the video display is promoted, and the difference in the deterioration progress between the lighting pixels is reduced, so that the deterioration promotion of the low-frequency pixel group by the light emission adjustment is relatively accelerated. , The same effect as the above case is expected.

(Second Embodiment)
The display device 1 according to the second embodiment will be described with reference to FIGS. 9 and 10.

As shown in FIG. 9, the display device 1 of the present embodiment has illuminance information of the surrounding environment of the display panel 2 based on the illuminance sensor 4 arranged in the vicinity of the display panel 2 and the output signal from the illuminance sensor 4. It is different from the first embodiment in that it includes an illuminance information acquisition unit 37 for acquiring the above. In this embodiment, this difference will be mainly described.

The illuminance sensor 4 is a device that is arranged in or near the display panel 2 and outputs a signal according to the brightness of the surrounding environment of the display panel 2. The illuminance sensor 4 is an arbitrary sensor such as a phototransistor that outputs an electric signal according to the incident light intensity. The illuminance sensor 4 is connected to the display control unit 3 by wiring (not shown), and outputs a signal corresponding to the illuminance of the ambient environment of the display panel 2 (hereinafter referred to as “ambient illuminance”) to the display control unit 3. The arrangement and number of the illuminance sensors 4 are arbitrary.

In the present embodiment, the display control unit 3 further includes an illuminance information acquisition unit 37, acquires information on the illuminance of the surrounding environment of the display panel 2 based on the output signal from the illuminance sensor 4, and is based on the illuminance. It is configured to adjust the illuminance.

The illuminance information acquisition unit 37 acquires information on the ambient illuminance of the display panel 2 based on the output signal from the illuminance sensor 4. The ambient illuminance information acquired by the illuminance information acquisition unit 37 is used for switching the light emission adjustment on / off in the light emission adjustment unit 35.

In the present embodiment, the display control unit 3 adjusts the light emission, for example, when the ambient illuminance is equal to or higher than a predetermined value, that is, when it is difficult for the user to perceive the increase in the brightness of the low-frequency pixel group due to the light emission adjustment. The light emission adjustment by the unit 35 is executed. On the other hand, when the ambient illuminance is less than a predetermined value, that is, when the brightness increase of the low-frequency pixel group due to the light emission adjustment is easily perceived by the user, the display control unit 3 adjusts the light emission by the light emission adjustment unit 35. Do not execute.

For example, in the storage unit 31 of the display control unit 3, in the present embodiment, the first data table for executing only the correction by the correction unit 34, the correction by the correction unit 34, and the light emission adjustment by the light emission adjustment unit 35 are performed. A second data table for executing both is stored. Then, the display control unit 3 selects either the first data table or the second data table according to the ambient illuminance, and performs only the correction by the correction unit 34, or the correction and the light emission adjustment by the light emission adjustment unit 35. Run. The threshold value of the ambient illuminance may be, for example, 1000 lux, but the present invention is not limited to this, and may be changed as appropriate.

Next, an example of processing operation in the light emission adjustment in the display device 1 of the present embodiment will be described with reference to FIG. 10, but here, the differences from the first embodiment will be mainly described.

In the present embodiment, as shown in FIG. 10, for example, when a video signal is input from the outside in step S101, the display control unit 3 calculates the cumulative light emission time for each constituent pixel in step S102 and stores it in the storage unit 31. Remember. Then, in step S103, the light emission adjusting unit 35 refers to the cumulative light emission time data stored in the storage unit 31 and sets the pixel having the longest cumulative light emission time as the high frequency pixel.

In the following step S201, the display control unit 3 acquires information on the ambient illuminance of the display panel 2 based on the output signal from the illuminance sensor 4.

In step S202, the display control unit 3 determines whether or not the ambient illuminance acquired in step S201 is equal to or greater than a predetermined value, and if it is affirmative, proceeds to step S104. On the other hand, if a negative determination is made in step S202, the display control unit 3 skips the process of step S104 and temporarily ends the process.

In step S104, the display control unit 3 performs light emission adjustment for causing only the low-frequency pixel group among the constituent pixel groups of the display panel 2 to emit light, as in the first embodiment.

For example, according to the above control flow, the display panel 2 adjusts the light emission only when it is difficult for the user to perceive the change in the brightness of the low-frequency pixel group due to the light emission adjustment between normal video displays. It becomes. The above control flow is just an example, and the order of the processing steps may be changed within a possible range. For example, the acquisition of illuminance information in step S201 is not limited to after step S103, and may be executed before step S103.

According to the present embodiment, in addition to the effect of the first embodiment, the light emission adjustment is performed only in the situation where the brightness change of the low frequency pixel group due to the light emission adjustment is inconspicuous based on the illuminance of the surrounding environment of the display panel 2. Therefore, the display device 1 has the effect of not causing the user to feel a sense of discomfort.

(Other embodiments)
Although the present invention has been described in accordance with Examples, it is understood that the present invention is not limited to the Examples and structures. The present invention also includes various modifications and modifications within a uniform range. In addition, various combinations and forms, as well as other combinations and forms including only one element thereof, more or less, are also within the scope and ideology of the present invention.

2 Display panel 3 Display control unit 31 Storage unit 34 Light emission adjustment unit 36 Signal output unit 37 Illuminance information acquisition unit 4 Illuminance sensor

Claims (8)

A display control device that executes display control of a display panel (2) having a plurality of pixels composed of self-luminous elements.
A storage unit (31) that stores the cumulative light emission time for each pixel, and
The pixel having the longest cumulative light emission time among the plurality of pixels is designated as a high-frequency pixel, and the group consisting of the pixels different from the high-frequency pixel among the plurality of pixels is designated as a low-frequency pixel group. A light emission adjusting unit (35) that generates a video signal that increases the light emission frequency of
A display control device including a display control unit (3) including a signal output unit (36) that outputs a video signal generated by the light emission adjusting unit to the display panel. The light emission adjusting unit inserts a correction video frame for inserting a correction video frame for turning off the high-frequency pixels and turning on the low-frequency pixels between the continuous first video frame and the second video frame. The display control device according to claim 1, wherein the display control device is generated. The display control unit is arranged in the display panel or in the vicinity of the display panel, and acquires the illuminance information from the illuminance sensor that outputs a signal corresponding to the illuminance in the surrounding environment of the display panel (37). )
The display control device according to claim 1 or 2, wherein the light emission adjusting unit generates the video signal only when the illuminance is a predetermined value or more. The lit pixel among the plurality of the pixels is defined as a lit pixel, and the ratio of the lit pixel to the plurality of pixels is defined as a lit rate.
The display control unit lowers the brightness of the lighting pixel when the lighting rate exceeds a predetermined threshold value, and when the lighting rate is equal to or less than the threshold value, the pixel having a relatively high brightness among the lighting pixels. The display control device according to any one of claims 1 to 3, wherein the control for increasing the brightness of the pixel having a relatively low brightness among the lighting pixels is executed while maintaining the brightness as it is. A display panel (2) having a plurality of pixels made of a self-luminous element, and
The storage unit (31) that stores the cumulative light emission time for each pixel and the pixel having the longest cumulative light emission time among the plurality of pixels are designated as high-frequency pixels, which are different from the high-frequency pixels among the plurality of the pixels. A light emission adjusting unit (35) that generates a video signal that increases the light emission frequency of the low frequency pixel group and an image signal generated by the light emission adjusting unit are output to the display panel, with the group consisting of the pixels as a low frequency pixel group. A display device including a signal output unit (36) and a display control unit (3) including the signal output unit (36). The light emission adjusting unit inserts a correction video frame for inserting a correction video frame for turning off the high-frequency pixels and turning on the low-frequency pixels between the continuous first video frame and the second video frame. The display device according to claim 5, wherein the display device is generated. An illuminance sensor (4) arranged on the display panel or in the vicinity of the display panel and outputting a signal according to the illuminance of the surrounding environment of the display panel.
An illuminance information acquisition unit (37) for acquiring the illuminance information from the illuminance sensor is further provided.
The display device according to claim 5 or 6, wherein the light emission adjusting unit generates the video signal only when the illuminance is a predetermined value or more. The lit pixel among the plurality of the pixels is defined as a lit pixel, and the ratio of the lit pixel to the plurality of pixels is defined as a lit rate.
The display control unit lowers the brightness of the lighting pixel when the lighting rate exceeds a predetermined threshold value, and when the lighting rate is equal to or less than the threshold value, the pixel having a relatively high brightness among the lighting pixels. The display device according to any one of claims 5 to 7, wherein the brightness of the lighting pixel is maintained as it is, and the control of increasing the brightness of the pixel having a relatively low brightness among the lighting pixels is executed.

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