JP2005283909A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device with which sticking life of a display is extended. <P>SOLUTION: In the display device having a display which causes emission luminescence deterioration according to display luminance and display time and function for combining and displaying a fixed pattern on an input video image, it is provided with a storage means which holds image data of the fixed pattern and a correction means for correcting the image data of the fixed pattern based on an input video signal and the image data of the fixed pattern in the case of displaying the image data of the fixed pattern held in the storage means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention has a display such as an organic EL panel, an inorganic EL panel, a PDP, etc. that causes emission luminance deterioration depending on display luminance and display time, and displays a fixed pattern combined with an input image. The present invention relates to a display device having a function to perform.

  In the organic EL element, the light emission luminance decreases according to the drive current amount and the display time. For this reason, in a digital camera or a mobile phone using an organic EL panel as a display panel, there is a problem that a burn-in phenomenon occurs when the same image such as an icon is continuously displayed.

  FIG. 1 shows a deterioration characteristic SL of an organic EL element when a low-luminance image such as a background is continuously displayed, and a deterioration characteristic SH of an organic EL element when a high-luminance image such as characters is continuously displayed. Show.

  As shown in FIG. 2A, it is assumed that a character M (fixed pattern, icon) is displayed in an arbitrary background H. In this example, when the gradation is represented by 8 bits (the higher the gradation is, the higher the luminance is), the luminance of the character portion M is 192 gradations. The luminance of the background portion H has various gradations, but in this example, it is 64 gradations.

  If it is assumed that various images are displayed in the background portion H, it is considered that the background portion H is generally a solid image even though the average luminance is large or small. When such a fixed pattern continues to be displayed for a long period of time and then an all-white image is displayed, the luminance deterioration of the pixel where the character M is displayed is larger than the luminance deterioration of the pixel where the background H is displayed. As shown in FIG. 2B, the luminance of the pixel MG on which the character M is displayed is comparable to that of, for example, 64 gradations, whereas the pixel HG on which the background H is displayed. The brightness of the image becomes the same level as that of 192 gradations, and the character portion is visually recognized as a burn-in image.

  In addition, as shown in FIG. 1, the period until the difference between the deterioration rates of two adjacent pixels reaches the limit width (the seizure visual recognition limit width) at which the seizure phenomenon becomes visible is defined as the seizure life. It is called.

  An object of the present invention is to provide a display device capable of extending the burn-in life of a display.

  The invention described in claim 1 has a display that causes emission luminance degradation depending on display luminance and display time, and in a display device having a function of combining and displaying a fixed pattern on an input video, When displaying the fixed pattern image data and the fixed pattern image data held in the storage means, the fixed pattern image data is displayed based on the input video signal and the fixed pattern image data. A correction means for correcting the image data is provided.

  According to the second aspect of the present invention, in the first aspect of the present invention, when α is a coefficient, Ain is fixed pattern image data, and Yin is input video data, the correction means {α × Ain + (1 It is characterized in that the image data of the fixed pattern is corrected by the calculation of −α) × Yin}.

  According to a third aspect of the present invention, in the second aspect of the invention, there is provided coefficient value control means for controlling the coefficient α in accordance with the video signal level of the background image in the vicinity of the fixed pattern.

  According to a fourth aspect of the invention, there is provided the invention according to the second aspect, further comprising coefficient value control means for controlling the coefficient α in accordance with an average value of input video signals for one screen.

  The invention according to claim 5 is the invention according to claim 2, further comprising coefficient value control means for controlling the coefficient α in accordance with the external light luminance.

  According to a sixth aspect of the present invention, in the first aspect of the present invention, the correction means determines whether the video signal level of the background image in the vicinity of the fixed pattern is less than or equal to a predetermined threshold value. If the discriminating means and α are coefficients, Ain is fixed pattern image data, and Yin is input video data, when the video signal level of the background image in the vicinity of the fixed pattern is less than the threshold, {α × Ain + (1− When the image data of the fixed pattern is corrected by the calculation of α) × Yin} and the video signal level of the background image in the vicinity of the fixed pattern is equal to or higher than the threshold value, the calculation of {−α × Ain + (1-α) × Yin} is performed. Means is provided for correcting image data of a fixed pattern.

  According to a seventh aspect of the invention, in the first aspect of the invention, the correction means determines whether the average value of the input video signal for one screen is less than or equal to a predetermined threshold value. If the discriminating means, α is a coefficient, Ain is fixed pattern image data, and Yin is input video data, if the average value of input video signals for one screen is less than the threshold, {α × Ain + (1− The image data of the fixed pattern is corrected by the calculation of α) × Yin}, and when the average value of the input video signal for one screen is equal to or greater than the threshold value, the calculation of {−α × Ain + (1-α) × Yin} is performed. Means is provided for correcting image data of a fixed pattern.

  The invention according to claim 8 is the invention according to claim 1, wherein the correction means determines whether the video signal level of the background image in the vicinity of the fixed pattern is less than or equal to a predetermined threshold value. If the discriminating means and α, γ are coefficients, Ain is fixed pattern image data, and Yin is input video data, when the video signal level of the background image in the vicinity of the fixed pattern is less than the threshold, {α × Ain + γ × Yin} is used to correct the fixed pattern image data. When the video signal level of the background image in the vicinity of the fixed pattern is equal to or greater than the threshold value, the fixed pattern image data is corrected using {−α × Ain + γ × Yin}. Means are provided.

  The invention according to claim 9 is the invention according to claim 1, wherein the correction means determines whether the average value of the input video signal for one screen is less than or equal to a predetermined threshold value. If the discriminating means, α and γ are coefficients, Ain is fixed pattern image data, and Yin is input video data, if the average value of input video signals for one screen is less than the threshold, {α × Ain + γ × Yin} is used to correct the fixed pattern image data. When the average value of the input video signal for one screen is equal to or greater than the threshold value, the fixed pattern image data is corrected using {−α × Ain + γ × Yin}. The display device having a display according to claim 1, further comprising: means.

  According to the present invention, the burn-in life of the display can be extended.

  Hereinafter, with reference to FIGS. 3 to 15, an embodiment in which the present invention is applied to a display device having an organic EL panel and having a function of synthesizing and displaying a fixed pattern on an input image is displayed. explain.

  As shown in FIG. 3A, when a fixed pattern (icon) such as a character is displayed in an arbitrary background, the icon image data is converted into icon image data Ain and background image data (input video signal). ) The display brightness for the icon is reduced by correcting it to a value obtained by combining Yin. This slows down the luminance deterioration speed of the portion where the icon is displayed. Assuming that the input video signal value is represented by 8 bits, the icon image data Ain is 255 and the background image data Yin is 128 in FIG. It is assumed that the position where each fixed pattern (icon) is displayed is fixedly determined.

  Assuming that the icon image data is Ain, the background image data is Yin, and the correction value of the icon image data is Aout, Aout is expressed by the following equation (1).

  Aout = α × Ain + (1−α) × Yin (1)

  α is a preset correction coefficient and takes a value greater than 0 and less than or equal to 1.

  When α = 0.5, as shown in FIG. 3B, the image data Aout of the corrected icon is 192. When α = 0.2, the image data Aout is as shown in FIG. As shown, the image data Aout of the corrected icon is 153.

  In this way, as shown in FIG. 4, when the icon (high brightness image) continues to be displayed, the deterioration characteristic SH of the organic EL element is SH (α = 0.5) when α = 0.5. ), And when α = 0.2, SH (α = 0.2). Note that SL is a deterioration characteristic of the organic EL element when the background (low-brightness image) is continuously displayed. FIG. 4 shows that the smaller the α is, the longer the seizure life is.

  FIG. 5 shows a configuration of a correction circuit for icon image data provided in a display device including an organic EL panel. Such a correction circuit is provided for each of the R, G, and B video signals, but only one correction circuit is shown here.

  The EEPROM 6 stores icon display data for each icon (fixed pattern). The icon display data for one icon is composed of data indicating a display pixel position (icon display position) where the icon is to be displayed and icon image data Ain to be displayed at each icon display position.

  The digital input video signal Yin includes a first multiplier 1 for multiplying by a coefficient β, an adder 2 for adding icon image data, and a DA converter for converting the output of the adder 2 into an analog signal ( DAC) 3 is sent to the display panel.

  The synchronization signal included in the input video signal Yin is sent to the position information calculation unit 4. The position information calculation unit 4 calculates position information of the currently input video signal based on the synchronization signal.

  The position information of the input video signal calculated by the position information calculation unit 4 is given to the icon display control unit 5. The icon display control unit 5 is also given an icon display control signal for designating the type of icon to be displayed in the current frame from a main controller (microcomputer) (not shown).

  When the icon display control signal specifies the type of icon to be displayed in the current frame by the icon display control signal, the icon display control unit 5 recognizes the icon display position to display the specified icon based on the data in the EEPROM 6, When the position information of the input video signal calculated by the position information calculation unit 4 matches the icon display position, the icon image data Ain to be displayed at the icon display position is read from the EEPROM 6 and output to the second multiplier 7. .

  Further, the icon display control unit 5 always causes the first multiplier 1 to select β = 1, and the position information of the input video signal calculated by the position information calculation unit 4 is the icon specified by the icon display control signal. When the display position coincides with the display position, a coefficient control signal for causing the first multiplier 1 to select β = (1−α) is output. The coefficient control signal is, for example, L level when β = 1 is selected by the first multiplier 1, and is H level when β = (1−α) is selected by the first multiplier 1. .

  When the coefficient control signal is at the L level, the first multiplier 1 sets β = 1, passes the input video signal Yin as it is, and sends it to the adder 2. When the coefficient control signal is at the H level, β = (1−α), the input video signal Yin is multiplied by (1−α), and the multiplication result {(1−α) × Yin} is added. Send to 2. The value of α is set in the first multiplier 1 in advance.

  When the icon image data Ain is sent from the icon display control unit 5, the second multiplier 7 multiplies the icon image data Ain by α and sends the multiplication result (α × Ain) to the adder 2. The value of α is set in the second multiplier 7 in advance.

  The adder 2 adds the data sent from the first multiplier 1 and the data sent from the second multiplier 7. Therefore, when the video signal Yin corresponding to the display position where the icon is to be displayed is input, the first video multiplier 1 multiplies the input video signal Yin by (1-α), and the second multiplier 7 Since the icon image data Ain corresponding to the icon is multiplied by α and the added data is added by the adder 2, data corresponding to Aout in the above equation (1) is output from the adder 2. The analog video signal is converted by the DAC 3 and then sent to the display panel.

  When the video signal Yin corresponding to the display position where the icon is not displayed is input, the input video signal Yin is output from the adder 2. The analog video signal is converted by the DAC 3 and then sent to the display panel.

  In the first embodiment, the video signal value corresponding to the icon is corrected using the same coefficient value α regardless of the background luminance (the luminance of the input video). For this reason, the difference between the brightness of the icon after correction and the brightness of the background becomes large between the case where the input video is a low brightness video and the case of a high brightness video.

  Therefore, in the second embodiment, the image data of the icon is corrected using the same equation as the above equation (1), but the value of the coefficient α is automatically changed according to the background luminance (the luminance of the input video). I am doing so. That is, the value of α is controlled so that the coefficient α increases as the background luminance increases. However, if the background luminance is higher than the luminance of the icon, α = 1.

  As shown in FIG. 6A, when the image data Ain of the icon is 200, the background video signal value Yin is 64, and the background video signal value Yin is relatively low, α is a small value. (In this example, α = 0.2). When α is set in this way, the corrected image data Aout of the icon is 91, and the signal difference between the background and the icon is 27.

  Further, as shown in FIG. 6B, when the image data Ain of the icon is 200, the background video signal value Yin is 150, and the background video signal value Yin is relatively high, α is set. A large value (α = 0.5 in this example) is set. When α is set in this way, the image data Aout of the corrected icon is 175, and the signal difference between the background and the icon is 25.

  As shown in FIG. 6C, when the icon image data Ain is 200 and the background video signal value Yin is 255, the background video signal value Yin is larger than the icon image data Ain. Sets α to 1.

  FIG. 7 shows a configuration of a correction circuit for icon image data provided in a display device having an organic EL panel. In FIG. 7, the same components as those in FIG.

  In the correction circuit of FIG. 7, the average value calculation unit 11 for calculating the average value of the input video signal Yin for each frame (the average value of the input video signal Yin within one frame) and the average value calculation unit 11 are used. A coefficient value control unit 12 that controls the value of α in the current frame based on the average value of the video signal one frame before is provided. In this embodiment, the average value of the video signal of the previous frame is regarded as the background luminance, and the value of the coefficient α is controlled based on the average value of the video signal of the previous frame.

  The coefficient value control unit 12 determines the value of α used in the current frame based on the coefficient value control table as shown in FIG. 8, and sets the value of α to the first multiplier 1 and the second multiplier 7. Set. That is, the coefficient value control unit 12 sets α to 0.1 when the average value of the video signal one frame before is less than 50, and sets the value when the average value of the video signal one frame before is 50 or more and less than 100. When α is 0.2 and the average value of video signal one frame before is 100 or more and less than 150, when α is 0.5 and the average value of video signal one frame before is 150 or more and less than 200, If α is 0.8 and the average value of the video signal one frame before is 200 or more, α is determined to be 1.0.

  The coefficient α is controlled based on the average value of the input video signal Yin within one frame, but the coefficient α is controlled based on the video signal level of the background image near the icon (fixed pattern). May be.

  In the first embodiment, the video signal value corresponding to the icon is corrected using the same coefficient value α regardless of the external light illuminance. The icon can be recognized even if the brightness of the icon is lowered when the illuminance of the external light is low. However, if the brightness of the icon is lowered when the illuminance of the external light is high, the icon is difficult to recognize.

  Thus, in the third embodiment, the image data of the icon is corrected using the same equation as the above equation (1), but the value of the coefficient α is automatically changed according to the illuminance of outside light. That is, the value of α is controlled so that the coefficient α increases as the external light illuminance increases.

  As shown in FIG. 9, when displaying an image whose icon image data Ain is 200 and the background video signal value Yin is 64, when the external light illuminance is low (1000 Lx), α is a small value (this In the example, α = 0.2) is set. When the external light illuminance is medium (10000 Lx), α is set to a medium value (α = 0.5 in this example). When the external light illuminance is high (50000 Lx), α is set to a large value (α = 1.0 in this example).

  FIG. 10 shows a configuration of a correction circuit for icon image data provided in a display device having an organic EL panel. 10, the same components as those in FIG. 5 are denoted by the same reference numerals, and the description thereof is omitted.

  In the correction circuit of FIG. 10, an illuminance sensor 21 for detecting external light illuminance, an external light illuminance calculation unit 22 that calculates external light illuminance based on a detection signal of the illuminance sensor 21, and an external light calculated by the external light illuminance calculation unit 22. A coefficient value control unit 23 that controls the value of α based on the light illuminance is provided.

  The coefficient value control unit 23 determines the value of α used in the current frame based on the coefficient value control table as shown in FIG. 11, and sets the value of α to the first multiplier 1 and the second multiplier 7. Set. That is, the coefficient value control unit 23 sets α to 0.2 when the external light illuminance is less than 1000 Lx, α to 0.35 when the external light illuminance is 1000 Lx or more and less than 5000 Lx, and the external light illuminance is 5000 Lx or more. Α is determined to be 0.5 when it is less than 10000 Lx, α is set to 0.75 when the ambient light illuminance is 10000 Lx or more and less than 50000 Lx, and α is determined to be 1.0 when the ambient light illuminance is 50000 Lx or more. To do.

  The value of the coefficient α is controlled based on the average value of the input video signal Yin within one frame and the ambient light illuminance, but the coefficient is based on the video signal level of the background image near the icon (fixed pattern) and the ambient light illuminance. The value of α may be controlled.

  The fourth embodiment is a combination of the second embodiment and the third embodiment. That is, in the fourth embodiment, the video signal value of the icon is corrected using the same formula as the above formula (1), but the coefficient α depends on the external light illuminance and the average value of the input video signal one frame before. The value of is automatically changed.

  FIG. 12 shows a configuration of a correction circuit for icon image data provided in a display device provided with an organic EL panel. In FIG. 11, the same components as those in FIG.

  In the correction circuit of FIG. 11, the illuminance sensor 21 for detecting the illuminance of external light, the external light illuminance calculation unit 22 for calculating the external light illuminance based on the detection signal of the illuminance sensor 21, and the average of the input video signal Yin for each frame. An average value calculating unit 11 for calculating a value (an average value of input video signals in one frame), an external light illuminance calculated by the external light illuminance calculating unit 22, and a frame one frame before calculated by the average value calculating unit 11 A coefficient value control unit 12 that controls the value of α in the current frame based on the video signal average value is provided.

  The coefficient value control unit 12 determines the value of α used in the current frame based on the coefficient value control table as shown in FIG. 13, and sets the value of α to the first multiplier 1 and the second multiplier 7. Set. That is, the coefficient value control unit 12 determines α so that the value of α decreases as the external light illuminance decreases, and the value of α decreases as the video signal average value of the previous frame decreases.

  In the fifth embodiment, a correction formula for correcting the video signal value of the icon is determined depending on whether the background luminance (the average value of the input video signal in one frame) is less than or equal to a predetermined threshold value. It is to switch.

  That is, when the average value of the input video signal is less than the threshold value TH, the icon image data is corrected based on the following formula (2). When the average value of the input video signal is equal to or greater than the threshold value TH, the following formula (3 ) To correct the icon image data.

Aout = α × Ain + (1−α) × Yin (2)
Aout = −α × Ain + (1−α) × Yin (3)

  Ain is the icon image data, Yin is the average value of the input video signal, and Aout is the correction value of the icon image data.

  In such a correction method, when the average value of the input video signal (background video signal value) is equal to or greater than the threshold value TH, the image data of the icon is corrected using only equation (2). Icon image data can be greatly reduced.

  Assuming that the threshold value TH is 128 and α is 0.2, as shown in FIG. 14A, the icon image data Ain is 200 and the background video signal value Yin is 64. When the video signal value Yin is less than the threshold value TH, the image data of the icon is corrected based on the above equation (2). As a result, the corrected icon image data Aout is 91.

  As shown in FIG. 14B, when the icon image data Ain is 200, the background video signal value Yin is 180, and the background video signal value Yin is greater than or equal to the threshold value TH, The icon image data is corrected based on the above equation (3). As a result, the corrected icon image data Aout is 104.

  FIG. 15 shows a configuration of a correction circuit for icon image data provided in a display device including an organic EL panel. 15 that are the same as those in FIG. 5 are given the same reference numerals, and descriptions thereof are omitted.

  In the correction circuit of FIG. 15, an average value calculation unit 31 for calculating the average value of the input video signal Yin for each frame, and the video signal average value of the previous frame calculated by the average value calculation unit 31 is the threshold value TH. A comparator 32 is provided for determining whether the value is less than or less than the threshold value TH and outputting a control signal representing the determination result. The control signal of the comparator 32 is given to the second multiplier 7.

  Α is set in advance in the first multiplier 1 and the second multiplier 7. When the control signal of the comparator 32 indicates that the average value of the video signal one frame before is less than the threshold value TH, the second multiplier 7 sends icon image data sent from the icon display control unit 5. Multiply Ain by α. When the control signal of the comparator 32 indicates that the average value of the video signal one frame before is greater than or equal to the threshold value TH, the icon image data Ain sent from the icon display control unit 5 is multiplied by -α. .

  The correction formula for correcting the video signal value of the icon is switched depending on whether the average value of the input video signal within one frame is less than or equal to a predetermined threshold, but the icon (fixed pattern) The correction formula for correcting the video signal value of the icon may be switched depending on whether the video signal level of the nearby background image is less than or greater than the threshold.

  Note that when the average value of the input video signals in one frame (or the video signal level of the background image near the icon) is less than the threshold value TH, the video signal value of the icon is corrected based on the following equation (4). When the average value of the input video signals in the frame (or the video signal level of the background image near the icon) is equal to or higher than the threshold value TH, the video signal value of the icon may be corrected based on the following equation (5).

Aout = α × Ain + γ × Yin (4)
Aout = −α × Ain + γ × Yin (5)

  γ is a coefficient. Assuming that the threshold value TH is 128, α is 0.2, and γ is 1.0, as shown in FIG. 16A, the icon image data Ain is 200, and the background video signal value. When Yin is 64 and the background video signal value Yin is less than the threshold value TH, the icon image data is corrected based on the above equation (4). As a result, the corrected icon image data Aout is 104.

  As shown in FIG. 16B, when the icon image data Ain is 200, the background video signal value Yin is 180, and the background video signal value Yin is greater than or equal to the threshold value TH, The image data of the icon is corrected based on the above formula (5). As a result, the corrected icon image data Aout is 140.

  When correction is performed in this way, γ is set in advance in the first multiplier 1 of FIG. 15 instead of α. When the icon is not displayed, the multiplication coefficient β of the first multiplier 1 is β = 1, and when the icon is displayed, the multiplication coefficient β of the first multiplier 1 is β = γ. If γ is set to 1, the first multiplier 1 is not necessary.

It is a graph which shows the deterioration characteristic SL of the organic EL element at the time of continuing displaying a low-intensity image, such as a background, and the deterioration characteristic SH of the organic EL element at the time of continuing displaying a high-intensity image, such as a character. . It is a schematic diagram which shows that a character part is visually recognized as a burn-in image. It is a schematic diagram for demonstrating the view of 1st Example. It is a graph for demonstrating the effect of 1st Example. It is a block diagram which shows the correction circuit of the icon image data for implement | achieving 1st Example. It is a schematic diagram for demonstrating the view of 2nd Example. It is a block diagram which shows the correction circuit of the icon image data for implement | achieving 2nd Example. It is a schematic diagram which shows the content of the coefficient value control table set to the coefficient value control part 12 of FIG. It is a schematic diagram for demonstrating the view of 3rd Example. It is a block diagram which shows the correction circuit of the icon image data for implement | achieving 3rd Example. It is a schematic diagram which shows the content of the coefficient value control table set to the coefficient value control part 23 of FIG. It is a block diagram which shows the correction circuit of the icon image data for implement | achieving 4th Example. It is a schematic diagram which shows the content of the coefficient value control table set to the coefficient value control part 12 of FIG. It is a schematic diagram for demonstrating the view of 5th Example. It is a block diagram which shows the correction circuit of the icon image data for implement | achieving 4th Example. It is a schematic diagram for demonstrating the modification of 5th Example.

Explanation of symbols

1 First Multiplier 2 Adder 3 DAC
4 position information calculation unit 5 icon display control unit 6 EEPROM
7 Second multiplier 11, 31 Average value calculation unit 12, 23 Coefficient value control unit 21 Illuminance sensor 22 Ambient light illuminance calculation unit 32 Comparator

Claims (9)

In a display device having a display that causes light emission luminance deterioration depending on display luminance and display time, and having a function of combining and displaying a fixed pattern on an input video,
When displaying the fixed pattern image data and the fixed pattern image data held in the storage means, the fixed pattern image data is displayed based on the input video signal and the fixed pattern image data. Correction means for correcting image data;
A display device comprising: When α is a coefficient, Ain is fixed pattern image data, and Yin is input video data, the correction means corrects the fixed pattern image data by an operation of {α × Ain + (1−α) × Yin}. The display device according to claim 1, wherein the display device is a device. The display device according to claim 2, further comprising coefficient value control means for controlling the coefficient α in accordance with the video signal level of the background image in the vicinity of the fixed pattern. 3. A display device having a display according to claim 2, further comprising coefficient value control means for controlling the coefficient α in accordance with an average value of input video signals for one screen. 3. The display device according to claim 2, further comprising coefficient value control means for controlling the coefficient α in accordance with the external light luminance. The correction means is
Discriminating means for discriminating whether the video signal level of the background image in the vicinity of the fixed pattern is less than or equal to a predetermined threshold, α is a coefficient, Ain is the image data of the fixed pattern, and Yin is the input video As data, when the video signal level of the background image in the vicinity of the fixed pattern is less than the threshold value, the image data of the fixed pattern is corrected by the calculation of {α × Ain + (1−α) × Yin}, and the background in the vicinity of the fixed pattern is corrected. Means for correcting image data of a fixed pattern by an operation of {−α × Ain + (1−α) × Yin} when the video signal level of the image is equal to or greater than a threshold;
The display device according to claim 1, further comprising: The correction means is
Discriminating means for discriminating whether the average value of the input video signal for one screen is less than or equal to a predetermined threshold value, α as a coefficient, Ain as fixed pattern image data, and Yin as input video As data, when the average value of the input video signal for one screen is less than the threshold, the image data of the fixed pattern is corrected by the calculation of {α × Ain + (1−α) × Yin}, and the input for one screen is performed. 2. The apparatus according to claim 1, further comprising means for correcting image data of a fixed pattern by an operation of {−α × Ain + (1−α) × Yin} when the average value of the video signal is equal to or greater than a threshold value. The display device described. The correction means is
Discriminating means for discriminating whether the video signal level of the background image in the vicinity of the fixed pattern is less than or equal to a predetermined threshold, and α and γ as coefficients, Ain as fixed pattern image data, and Yin as As input video data, when the video signal level of the background image in the vicinity of the fixed pattern is less than the threshold, the image data of the fixed pattern is corrected by the calculation of {α × Ain + γ × Yin}, and the video of the background image in the vicinity of the fixed pattern Means for correcting image data of a fixed pattern by an operation of {−α × Ain + γ × Yin} when the signal level is equal to or higher than a threshold value;
The display device according to claim 1, further comprising: The correction means is
Discriminating means for discriminating whether the average value of the input video signal for one screen is less than or equal to a predetermined threshold value, α and γ as coefficients, Ain as fixed pattern image data, and Yin as Assuming that the input video data is the average value of the input video signal for one screen is less than the threshold, the image data of the fixed pattern is corrected by the operation of {α × Ain + γ × Yin}, and the input video signal for one screen is corrected. 2. The display device according to claim 1, further comprising means for correcting image data of a fixed pattern by an operation of {−α × Ain + γ × Yin} when the average value is equal to or greater than a threshold value.

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