JPWO2011108097A1 - Afterimage suppression apparatus and afterimage suppression method - Google Patents

Abstract

Provided are an afterimage suppressing apparatus and an afterimage suppressing method capable of suppressing an afterimage generated on a display screen with a simple configuration. The afterimage suppression device (100) used in the projection display device having the light control unit (130) for adjusting the light amount from the light source is based on the image signal based on the light whose light amount has been adjusted by the light control unit (130). Based on the liquid crystal panel (120) that is modulated and displayed as an image, the new image signal, and the image signal received immediately before the new image signal, the image indicated by the image signal is a still image. And a control unit (140) that increases or decreases the amount of light adjusted by the dimming unit (130) according to the result.

Description

  The present invention relates to an afterimage suppressing apparatus and an afterimage suppressing method.

  In projectors having a liquid crystal panel, the brightness of an image displayed on a screen is increasing. A projector having a liquid crystal panel, for example, increases the power supplied to the lamp to increase the light quantity of the lamp, thereby increasing the light quantity supplied to the liquid crystal panel, thereby increasing the brightness.

  When the amount of light supplied to the liquid crystal panel increases, the temperature of the liquid crystal panel rises, so that the adhesion of impurities in the liquid crystal is accelerated. When the adhesion of impurities in the liquid crystal is accelerated, when the same image is continuously displayed, the image is likely to remain as an afterimage, and in the worst case, the screen is burned.

  Patent Document 1 describes a screen burn-in prevention device. The screen burn-in prevention device described in Patent Literature 1 includes a still image / moving image determination processing unit, a movement control unit, and a shift unit including a specific lens.

  In the screen burn-in prevention device described in Patent Literature 1, the still image / moving image determination processing unit detects a data difference between the previously stored video data and the currently stored video data, and the detected difference Is determined to be a still image. When the still image / moving image determination processing unit continuously determines the still image, the movement control unit controls the shift means so that the display position of the video on the display screen is shifted.

JP 2006-259287 A

  In the screen burn-in prevention device described in Patent Document 1, the movement control unit controls the shift means to adjust the display position of the video on the display screen. For this reason, in order to adjust the display position of an image, it is necessary to provide a shift unit in the apparatus, which causes a problem that the configuration of the apparatus is complicated and the manufacturing cost increases.

  An object of the present invention is to provide an afterimage suppression apparatus and an afterimage suppression method that solve the above-described problems.

  The afterimage suppression apparatus of the present invention is an afterimage suppression apparatus used in a projection display apparatus having a light control unit that adjusts the light amount from a light source, and the light whose light amount has been adjusted by the light control unit is converted into an image. Based on the liquid crystal panel that is modulated based on the signal and displayed as an image, the new image signal, and the image signal received immediately before the new image signal, the image indicated by the image signal is a still image. Control means for determining whether or not there is, and increasing or decreasing the amount of light adjusted by the light control means according to the result.

  An afterimage suppression method of the present invention is an afterimage suppression method in an afterimage suppression apparatus used in a projection display device having a light control unit that adjusts the light amount from a light source, and the light amount is adjusted by the light control unit. The light is modulated based on the image signal and displayed as an image. Based on the new image signal and the image signal received immediately before the new image signal, the image indicated by the image signal is a still image. And the amount of light adjusted by the light control means is increased or decreased according to the result.

  According to the present invention, it is possible to suppress an afterimage generated on a display screen with a simple configuration.

It is a block diagram which shows the structural example of the afterimage suppression apparatus in embodiment of this invention. It is a figure which shows the relationship between the temperature of the liquid crystal panel 120, and an afterimage level. It is a figure which shows the relationship between the temperature of the liquid crystal panel 120, and response time. 5 is a flowchart illustrating an example of a processing procedure of an afterimage suppression method using a light emission amount adjustment unit 132. 6 is a flowchart illustrating an example of a processing procedure of an afterimage suppression method using a blocking amount adjusting unit.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration example of an afterimage suppressing apparatus according to an embodiment of the present invention.

  The afterimage suppression apparatus 100 receives an analog image signal (hereinafter referred to as “video signal”) and a synchronization signal for performing a display operation based on the video signal from a video signal line 101 and a synchronization signal line 102, respectively. It is a device used in a projection display device that accepts and displays an image on a screen. The video signal and the synchronization signal are supplied from a video supply device such as a personal computer, for example.

  The afterimage suppression apparatus 100 includes a reception unit 110, a liquid crystal panel 120, a light control unit 130, and a control unit 140. The light control unit 130 includes a lamp 131, a light emission amount adjustment unit 132, a blocking unit 133, and a blocking amount adjustment unit 134. The control unit 140 includes a memory 141, a CPU (Central Processing Unit) 142, and a counter 143.

  The accepting unit 110 accepts a video signal. The reception unit 110 includes an A / D (Analog / Digital) converter 111 and a frame memory 112.

  When receiving the video signal from the video signal line 101, the A / D converter 111 converts the video signal into a digital signal. The A / D converter 111 supplies the digital signal to the frame memory 112 as video data.

  The frame memory 112 receives the synchronization signal supplied from the synchronization signal line 102 and the video data supplied from the A / D conversion unit 111. When the frame memory 112 receives the synchronization signal and the video data, the frame memory 112 holds the video data in units of frames based on the synchronization signal. That is, the frame memory 112 sequentially holds video data of frames that are continuous in time series.

  For example, when a video signal is supplied from a personal computer, the frame memory 112 stores video data for one screen (frame) based on the horizontal synchronization signal and the vertical synchronization signal. Further, the frame memory 112 outputs the video data to the liquid crystal panel 120 and the control unit 140.

  The liquid crystal panel 120 modulates the light whose light amount from the lamp 131 is adjusted by the light control unit 130 based on the image signal, and displays it as an image. In the present embodiment, the liquid crystal panel 120 is a transmissive liquid crystal panel that is a display medium for video signals.

  The liquid crystal panel 120 modulates the light from the lamp 131 based on the video data from the frame memory 112. The liquid crystal panel 120 displays the modulated light as an image. The image displayed on the liquid crystal panel 120 is enlarged and displayed on the screen by a projection lens (not shown), for example.

  The liquid crystal panel 120 has a characteristic that an afterimage tends to remain on the display screen as the temperature of the liquid crystal panel 120 increases, and the response speed decreases as the temperature decreases.

  The liquid crystal panel 120 rises in temperature as the amount of light supplied from the light control unit 130 increases. As the temperature of the liquid crystal panel 120 rises, the adhesion of impurities in the liquid crystal becomes faster, so that an afterimage tends to remain in the image displayed by the liquid crystal panel 120.

  FIG. 2 is a diagram illustrating the relationship between the temperature of the liquid crystal panel 120 and the afterimage level. In FIG. 2, the horizontal axis represents the temperature of the liquid crystal panel 120, and the vertical axis represents the afterimage level indicating the degree of afterimage generated on the display screen.

  As shown in FIG. 2, it can be seen that the afterimage tends to remain as the temperature of the liquid crystal panel 120 increases. Therefore, as the amount of light supplied to the liquid crystal panel 120 increases, the temperature of the liquid crystal panel 120 becomes higher, and an afterimage tends to remain.

  In addition, the temperature of the liquid crystal panel 120 decreases as the amount of light supplied from the light control unit 130 decreases. The response speed of the liquid crystal panel 120 decreases as the temperature decreases.

  FIG. 3 is a diagram illustrating the relationship between the temperature of the liquid crystal panel 120 and the response time. In FIG. 3, the horizontal axis represents the temperature of the liquid crystal panel 120, and the vertical axis represents the response time of the liquid crystal panel 120.

  As shown in FIG. 3, it can be seen that the response speed decreases when the temperature of the liquid crystal panel 120 decreases too much. For this reason, as the amount of light supplied to the liquid crystal panel 120 decreases, the temperature of the liquid crystal panel 120 decreases and the influence on the image quality increases.

  The light control unit 130 can be generally referred to as light control means.

  The dimmer 130 adjusts the amount of light from the lamp 131. That is, the light control unit 130 adjusts the amount of light supplied to the liquid crystal panel 120.

  The dimmer 130 adjusts the amount of light supplied to the liquid crystal panel 120 by changing the magnitude of the drive power supplied to the lamp 131. The dimmer 130 adjusts the amount of light supplied to the liquid crystal panel 120 by changing the amount of light blocked from the lamp 131.

  The lamp 131 supplies light to the liquid crystal panel 120 as a light source. The lamp 131 receives light from the light emission amount adjustment unit 132 and emits light. The lamp 131 increases in light emission amount as the driving power increases.

  The light emission amount adjustment unit 132 adjusts the amount of light supplied to the liquid crystal panel 120 by increasing or decreasing the amount of drive power supplied to the lamp 131 according to the control of the CPU 142.

  For example, the light emission amount adjustment unit 132 receives information (hereinafter referred to as “reference information”) indicating a predetermined light amount (hereinafter referred to as “reference light amount”) from the CPU 142. When receiving the reference information, the light emission amount adjustment unit 132 supplies driving power corresponding to the reference light amount indicated in the reference information to the lamp 131.

  In addition, the light emission amount adjustment unit 132 receives, from the CPU 142, for example, information indicating the ratio of the light amount supplied to the liquid crystal panel 120 to the reference light amount (hereinafter referred to as “ratio information”). When receiving the ratio information, the light emission amount adjustment unit 132 supplies the lamp 131 with driving power corresponding to the amount of light indicated by the ratio information (for example, 90% and 80%).

  Note that, if the light emission amount of the lamp 131 is excessively reduced, flickering (flicker phenomenon) occurs in the light of the lamp 131. Therefore, the lower limit of the ratio to the reference light amount is generally limited to about 80%.

  The blocking unit 133 blocks part or all of the light emitted from the lamp 131. The blocking unit 133 is configured by, for example, a diaphragm mechanism.

  The blocking amount adjusting unit 134 adjusts the amount of light supplied to the liquid crystal panel 120 by driving the blocking unit 133 according to the control of the CPU 142 and increasing or decreasing the opening area through which the light flux of the lamp 131 passes.

  Since the blocking amount adjusting unit 134 physically blocks light, the blocking amount is not limited. For this reason, the cutoff amount adjusting unit 134 can make the increase / decrease width of the amount of light supplied to the liquid crystal panel 120 larger than that of the light emission amount adjusting unit 132.

  For example, when the reference amount information is received from the CPU 142, the cutoff amount adjustment unit 134 adjusts the opening area so that the reference light amount indicated by the reference information is obtained. Further, for example, when the cutoff amount adjusting unit 134 receives the ratio information from the CPU 142, the light amount supplied to the liquid crystal panel 120 is set to a light amount of the ratio (for example, 60%, 20%) indicated in the ratio information. , Adjust the opening area.

  Control unit 140 can generally be referred to as control means.

  Based on the new video signal received by the receiving unit 110 and the video signal received immediately before the newly received video signal, the control unit 140 converts the image indicated by the video signal into a still image. It is determined whether or not. Moreover, the control part 140 increases / decreases the light quantity adjusted in the light control part 130 according to a determination result.

The control unit 140 stores a predetermined first threshold value (hereinafter referred to as “threshold value B”) and an initial value indicating the reference light amount, and whether the image indicated in the video signal is a still image. A count value obtained by counting the number of times of determination is accumulated, and when it is determined that the image indicated in the video signal is not a still image, the count value is reset to the light amount indicated by the initial value.
The control unit 140 increments the count value when determining that the image indicated by the image signal is a still image, and decreases the light amount by a predetermined amount when the value is smaller than the threshold value B.
In addition, the control unit 140 stores a second threshold value (hereinafter referred to as “threshold value A”) that is smaller than the predetermined threshold value B, and when the value obtained by incrementing the count value is equal to or greater than the threshold value A. The amount of light supplied to the liquid crystal panel 120 is reduced by a predetermined amount. The control unit 140 then increments the incremented value, and if the value is equal to or greater than the threshold value B, the light amount decreased by a predetermined amount is further decreased by a predetermined amount.

  The memory 141 is a work memory of the CPU 142. The memory 141 holds video data supplied from the CPU 142. In the present embodiment, the memory 141 holds two video data that are continuous in time series received by the frame memory 112.

  That is, the memory 141 includes new video data supplied from the CPU 142 (hereinafter referred to as “latest video data”) and video data held immediately before the latest video data (hereinafter referred to as “previous video data”). Is held). Further, the memory 141 stores a threshold value A and an initial value indicating the threshold value B and the reference light amount.

  The CPU 142 controls each of the adjustment unit of the light emission amount adjustment unit 132 or the cutoff amount adjustment unit 134 and the counter 143.

  Based on the two pieces of video data stored in the memory 141, the CPU 142 determines whether the image indicated by the video data is a still image or a moving image. The CPU 142 adjusts the temperature of the liquid crystal panel 120 by increasing or decreasing the amount of light supplied to the liquid crystal panel 120 according to the result.

  In the present embodiment, when the video data is newly stored in the frame memory 112, the CPU 142 holds the video data stored in the frame memory 112 in the memory 141 as the latest video data.

  Further, the CPU 142 collates the latest video data held in the memory 141 with the immediately preceding video data, and determines whether the image indicated by these video data is a still image or a moving image.

  That is, the CPU 142 calculates the degree of correlation indicating the correlation between the latest video data and the previous video data, and the calculation result is a predetermined threshold (hereinafter referred to as “correlation threshold”). Judge whether or not it exceeds. When the calculation result exceeds the correlation threshold, the CPU 142 determines that the image is a still image, and when the calculation result is equal to or less than the threshold, the CPU 142 determines that the image is a moving image. The correlation threshold is held in the memory 141.

  For example, the CPU 142 compares the data corresponding to the predetermined area on the display screen with respect to the latest video data and the immediately preceding video data, and calculates the difference between the two data (interframe difference) as the degree of correlation. In this example, the degree of correlation decreases as the difference between the two data increases. The predetermined area is set, for example, near the four corners on the screen.

  If the CPU 142 determines that the video data is a still image, the CPU 142 outputs a count signal for incrementing the count value of the counter 143. In the present embodiment, the CPU 142 determines video data every time video data is stored in the frame memory 112, and outputs a count signal every time it is determined that the video data is a still image.

  In addition, when the count value is equal to or greater than the threshold value A stored in the memory 141, the CPU 142 determines rate information (hereinafter referred to as “first rate information”) for reducing the amount of light supplied to the liquid crystal panel 120 by a predetermined amount. Generated).

  For example, the CPU 142 supplies the light emission amount adjustment unit 132 with first ratio information for setting the ratio to the reference light amount to 90%. Alternatively, the CPU 142 supplies the cutoff rate adjusting unit 134 with the first rate information for setting the rate with respect to the reference light amount to 60%. Therefore, the CPU 142 can reduce the temperature of the liquid crystal panel 120 by reducing the amount of light supplied to the liquid crystal panel 120.

  In addition, when the count value is equal to or greater than the threshold value B indicated by the initial value of the memory 141, the CPU 142 further reduces rate information (hereinafter referred to as “the amount of light” indicated by the first rate information). Referred to as “second ratio information”). Therefore, when the count value is smaller than the threshold value B, the CPU 142 suppresses generation of the second ratio information.

  For example, the CPU 142 supplies the light emission amount adjustment unit 132 with second ratio information for setting the ratio to the reference light amount to 80%. Alternatively, the CPU 142 supplies the cutoff amount adjusting unit 134 with the second ratio information for setting the ratio with respect to the reference light amount to 20%. Therefore, the CPU 142 can further reduce the temperature of the liquid crystal panel 120 by further reducing the amount of light supplied to the liquid crystal panel 120.

  On the other hand, when the CPU 142 determines that the video data is a moving image, the CPU 142 outputs a reset signal for resetting the count value of the counter 143.

  When the CPU 142 determines that the video data is a moving image, the CPU 142 generates reference information indicating the reference light amount (100%) indicated in the initial value of the memory 141 as the light amount supplied to the liquid crystal panel 120, and The reference information is supplied to the light emission amount adjustment unit 132 or the cutoff amount adjustment unit 134.

  The counter 143 accumulates a count value obtained by counting the number of times that the determination that the image indicated by the video signal is a still image is continuously performed. The counter 143 outputs the count value to the CPU 142.

  When the counter 143 receives the count signal from the CPU 142, the counter 143 increases the count value by “1”. Further, upon receiving a reset signal from the CPU 142, the counter 143 resets the count value to “0”.

  Next, the operation of the afterimage suppression apparatus 100 will be described.

  FIG. 4 is a flowchart illustrating an example of a processing procedure of the afterimage suppression method using the light emission amount adjustment unit 132.

  First, the CPU 142 determines whether or not video data is stored in the frame memory 112 (step S911). When the video data is stored in the frame memory 112, the CPU 142 copies the same contents as the video data to the memory 141 (step S912).

  The CPU 142 collates the latest video data received by the frame memory 112 with the previous video data, and determines whether or not the degree of correlation exceeds the correlation threshold (step S913).

  If the degree of correlation is equal to or less than the correlation threshold, the CPU 142 determines that the video data is a moving image and sets the count value to “0” (step S918).

  When the count value is set to “0”, the CPU 142 supplies the reference information to the light emission amount adjustment unit 132, the light amount adjustment unit 132 sets the light amount to the reference light amount (100%), and the process returns to step S912 ( Step S919).

  On the other hand, when the CPU 142 determines that the video indicated by the video data is a still image, the CPU 142 increases the count value by one (step S914). When the count value is increased by 1, the CPU 142 determines whether or not the count value is equal to or greater than the threshold value A (step S915).

  If the count value is less than the threshold value A, the CPU 142 returns to step S912. On the other hand, when the count value is greater than or equal to the threshold A, the CPU 142 determines whether or not the count value is greater than or equal to the threshold B (step S916).

  When the count value is less than the threshold value B, the CPU 142 supplies the first ratio information to the light emission amount adjustment unit 132, and the light emission amount adjustment unit 132 sets the light amount to 90% with respect to the reference light amount (step). S920).

  On the other hand, when the count value is equal to or greater than the threshold value B, the CPU 142 supplies the second ratio information to the light emission amount adjustment unit 132, and the light emission amount adjustment unit 132 sets the light amount to 80% with respect to the reference light amount. (Step S917), the process returns to Step S912, and a series of processing procedures is repeated until the supply of the video data is completed.

  FIG. 5 is a flowchart illustrating an example of a processing procedure of the afterimage suppression method using the cutoff amount adjusting unit 134.

  First, the CPU 142 determines whether or not video data is stored in the frame memory 112 (step S921). When the video data is stored in the frame memory 112, the CPU 142 copies the same contents as the video data to the memory 141 (step S922).

  The CPU 142 collates the latest video data received by the frame memory 112 with the previous video data, and determines whether or not the degree of correlation exceeds the correlation threshold (step S923).

  If the correlation degree is equal to or less than the correlation threshold, the CPU 142 determines that the video indicated in the video data is a moving image, and sets the count value to “0” (step S928).

  When the count value is set to “0”, the CPU 142 supplies the reference information to the cutoff amount adjusting unit 134, and the cutoff amount 133 is driven by the cutoff amount adjusting unit 134 so that the light amount is set to the reference light amount (100%). The process returns to step S922 (step S929).

  On the other hand, when determining that the video indicated by the video data is a still image, the CPU 142 increases the count value by one (step S924). When the count value is increased by 1, the CPU 142 determines whether the count value is equal to or greater than the threshold value A (step S925).

  If the count value is less than the threshold value A, the CPU 142 returns to step S922. On the other hand, if the count value is greater than or equal to the threshold A, the CPU 142 determines whether or not the count value is greater than or equal to the threshold B (step S926).

  When the count value is less than the threshold value B, the CPU 142 supplies the first rate information to the cutoff amount adjusting unit 134, and the cutoff amount 133 is driven by the cutoff amount adjusting unit 134 so that the light amount is less than the reference light amount. It is set to 60% (step S930).

  On the other hand, when the count value is equal to or greater than the threshold value B, the CPU 142 supplies the second ratio information to the cutoff amount adjusting unit 134, and the cutoff amount 133 is driven by the cutoff amount adjusting unit 134 so that the light amount becomes the reference light amount. On the other hand, it is set to 20% (step S927), the process returns to step S922, and a series of processing procedures is repeated until the supply of the video data is completed.

  According to the present embodiment, the afterimage suppression apparatus 100 includes the liquid crystal panel 120 that displays the image by modulating the light whose light amount has been adjusted by the light control unit 130 based on the image signal, and the control unit 140 includes Based on the new image signal and the image signal received immediately before the new image signal, it is determined whether or not the image indicated by the image signal is a still image. For this reason, the afterimage suppression apparatus 100 can determine whether or not the afterimage is likely to remain in the display image.

  In the present embodiment, the control unit 140 determines whether or not the image indicated by the image signal is a still image, and increases or decreases the amount of light adjusted by the light control unit 130 according to the result. For this reason, the afterimage suppression apparatus 100 can reduce the temperature of the liquid crystal panel 120 by reducing the amount of light supplied to the liquid crystal panel 120 when still images are continuously displayed on the liquid crystal panel 120. it can.

  Therefore, the afterimage suppression device 100 reduces the temperature of the liquid crystal panel 120 when the still images are continuously displayed, thereby delaying the adhesion of impurities in the liquid crystal and making the afterimage hardly appear on the display screen. Can do.

  Further, the afterimage suppressing apparatus 100 adjusts the amount of light supplied to the liquid crystal panel 120 using the light control unit 130 and adjusts the temperature of the liquid crystal panel 120. For this reason, in the afterimage suppressing apparatus 100, since it is not necessary to newly provide an adjustment means for adjusting the temperature of the liquid crystal panel 120, it is possible to avoid the complexity of the apparatus configuration and to suppress an increase in manufacturing cost. Can do.

  Therefore, the afterimage suppression apparatus 100 can suppress afterimages generated in an image generated by the liquid crystal panel 120 with a simple configuration.

  In the present embodiment, the control unit 140 stores a predetermined first threshold value and an initial value indicating the amount of light, and determines whether the image indicated in the image signal is a still image. Accumulate the count value obtained by counting the number of times. If the control unit 140 determines that the image indicated by the image signal is not a still image, the control unit 140 resets the count value to obtain the light amount indicated by the initial value.

  Therefore, the afterimage suppression apparatus 100 increases the amount of light supplied to the liquid crystal panel 120 when the image indicated by the image signal is a moving image as compared to when the image is a still image. The deterioration of response characteristics can be improved.

  In the present embodiment, the control unit 140 increments the count value when the image indicated by the image signal is determined to be a still image, and the liquid crystal when the value is smaller than the first threshold value. The amount of light supplied to the panel 120 is decreased by a predetermined amount.

  Therefore, the afterimage suppression apparatus 100 keeps the amount of decrease in the amount of light supplied to the liquid crystal panel 120 constant unless the number of times that the image indicated by the image signal is a still image exceeds the predetermined number of times. maintain. For this reason, the afterimage suppression apparatus 100 can suppress the temperature of the liquid crystal panel 120 from excessively decreasing due to the excessive decrease in the amount of light supplied to the liquid crystal panel 120. Therefore, the afterimage suppressing apparatus 100 can prevent the response speed of the liquid crystal panel 120 from being excessively decreased due to the temperature decrease of the liquid crystal panel 120, and can suppress the deterioration of the quality of the display image.

  In the present embodiment, the control unit 140 stores a second threshold value that is smaller than a predetermined first threshold value, and if the incremented count value is equal to or greater than the second threshold value, the liquid crystal is displayed. The light amount supplied to the panel 120 is decreased by a predetermined amount, and then the incremented value is incremented. If the value is equal to or greater than the first threshold value, the light amount decreased by the predetermined amount is further decreased by a predetermined amount.

  For this reason, the afterimage suppression apparatus 100 can gradually reduce the amount of light supplied to the liquid crystal panel 120 as the period during which still images are continuously displayed becomes longer. Therefore, the afterimage suppression apparatus 100 reduces the amount of light supplied to the liquid crystal panel 120 in a stepwise manner in accordance with a situation in which an afterimage tends to remain, so that it is possible to reduce discomfort to the user due to fluctuations in the amount of light.

  In the present embodiment, the light emission amount adjustment unit 132 adjusts the amount of light supplied to the liquid crystal panel 120 by changing the magnitude of the driving power supplied to the lamp 131. For this reason, the afterimage suppression apparatus 100 can easily increase or decrease the temperature of the liquid crystal panel 120 by changing the light emission amount of the lamp 131.

  In the present embodiment, the blocking amount adjusting unit 134 adjusts the amount of light supplied to the liquid crystal panel 120 by changing the blocking amount of light from the lamp 131. Since the afterimage suppression apparatus 100 can reduce the amount of light supplied to the liquid crystal panel 120 as compared with the light emission amount adjustment unit 132, the increase / decrease width of the temperature of the liquid crystal panel 120 can be increased.

  Further, the afterimage suppression apparatus 100 may supply the liquid crystal panel 120 with a light amount larger than the light amount supplied when displaying a moving image when the still image is switched to the moving image. Thereby, the afterimage suppression apparatus 100 can shorten the time required for the temperature of the liquid crystal panel 120 to reach a predetermined designated temperature. For this reason, the response speed of the liquid crystal panel 120 can be improved in a shorter time.

  Further, the afterimage suppression apparatus 100 may supply the liquid crystal panel 120 with a light amount smaller than a light amount supplied when displaying a still image when the moving image is switched to a still image. Thereby, the afterimage suppression apparatus 100 can shorten the time required for the temperature of the liquid crystal panel 120 to reach a predetermined designated temperature. For this reason, the afterimage generated in the image of the liquid crystal panel 120 can be further reduced.

  In the present embodiment, the example in which the light amount supplied to the liquid crystal panel 120 is adjusted using one of the light emission amount adjusting unit 132 or the cutoff amount adjusting unit 134 has been described. It may be.

  In each embodiment described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.

DESCRIPTION OF SYMBOLS 100 Afterimage suppression apparatus 110 Reception part 111 A / D converter 112 Frame memory 120 Liquid crystal panel 130 Light control part 131 Lamp 132 Light emission amount adjustment part 133 Blocking part 134 Blocking amount adjustment part 140 Control part 141 Memory 142 CPU
143 counter

Claims (7)

An afterimage suppressing device used in a projection display device having a light control means for adjusting the amount of light from a light source,
A liquid crystal panel that modulates the light whose light amount has been adjusted by the light control means based on an image signal and displays it as an image;
Based on the new image signal and the image signal received immediately before the new image signal, it is determined whether the image shown in the image signal is a still image, and according to the result, And an afterimage suppression device including a control unit that increases or decreases the amount of light adjusted by the light control unit. The afterimage suppression device according to claim 1,
The control means stores a predetermined first threshold value and an initial value indicating the amount of light, and counts the number of times of determining whether the image indicated in the image signal is a still image When the image indicated in the image signal is determined not to be a still image, the count value is reset to the light amount indicated in the initial value, and the image indicated in the image signal is a still image. An afterimage suppression apparatus that increments the count value when determined, and decreases the light amount by a predetermined amount when the value is smaller than the first threshold. The afterimage suppressing device according to claim 2,
The control means stores a second threshold value that is smaller than the predetermined first threshold value, and if the incremented count value is greater than or equal to the second threshold value, the control unit controls the amount of light. An afterimage suppression apparatus that reduces the fixed amount, then increments the incremented value, and further reduces the amount of light reduced by the predetermined amount when the value is equal to or greater than the first threshold. The afterimage suppressing device according to any one of claims 1 to 3,
The afterimage suppressing device, wherein the light control unit adjusts the light amount by changing a magnitude of driving power supplied to the light source. In the afterimage suppression device according to any one of claims 1 to 4,
The afterimage suppressing device, wherein the light control unit adjusts the light amount by changing a light blocking amount from the light source. An afterimage suppression method in an afterimage suppression device used in a projection display device having a light control means for adjusting the amount of light from a light source,
The light whose light amount is adjusted by the light control means is modulated based on an image signal and displayed as an image,
Based on the new image signal and the image signal received immediately before the new image signal, it is determined whether the image shown in the image signal is a still image, and according to the result, An afterimage suppression method for increasing or decreasing the amount of light adjusted by the light control means. The afterimage suppression method according to claim 6,
Increasing or decreasing the amount of light
A predetermined first threshold value and an initial value indicating the amount of light are stored, and a count value obtained by counting the number of times that the image indicated in the image signal is determined to be a still image is accumulated, When it is determined that the image indicated in the image signal is not a still image, the count value is reset to the light amount indicated by the initial value, and when it is determined that the image indicated by the image signal is a still image. An afterimage suppression method including incrementing the count value and decreasing the light amount by a predetermined amount when the count value is smaller than the first threshold value.

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