Patent Application
20220189420
The present disclosure relates to image display apparatuses and, in particular, to an image display apparatus having a backlight.
Liquid-crystal display apparatuses are widely used as thin, light-weight, low-power consuming image display apparatuses. A liquid-crystal panel included in the liquid-crystal display apparatus is a non-light emitting display panel. For this reason, many liquid-crystal display apparatuses include backlights emitting light onto the rear surface of the liquid-crystal panel. The liquid-crystal display apparatus having the backlight is described below as an example of the image display apparatus having the backlight.
The liquid-crystal display apparatus may have video display performance that becomes lower if the backlight is continuously operated. A flashing backlight driving method is known as a method to increase the video display performance. In the liquid-crystal display apparatus performing the flashing backlight driving method, a light-emission duration of the backlight is set during one frame period and the backlight is active only during the light-emission duration. The flashing backlight driving method is also referred to as an impulse backlight driving method.
A scan backlight driving method is available to address the above problem. In the liquid-crystal display apparatus performing the scan backlight driving method, the backlight is segmented into multiple areas and the multiple areas are controlled such that the areas are sequentially one after another in a light-emission state at different timings.
The scan backlight driving method has a problem of luminance unevenness on the display screen where a bright line and a dark line are displayed at a location on the display screen corresponding to a border of the areas. The liquid-crystal display apparatus performing the scan backlight driving method has typically the backlight that is designed to leak light from one area to another area to reduce the luminance unevenness. However, if leakage light enters an area within a rewrite time, ghost occurs at the video edge. Referring to
Another method is available to increase color reproducibility of emission light from the backlight (hereinafter referred to as backlight light). This method employs KSF phosphor as a red-light phosphor included in a white-light light emitting diode (LED) in the backlight. The KSF phosphor is fluoride phosphor having a composition of K2SiF6:Mn4+ or K2TiF6:Mn4+.
The liquid-crystal display apparatuses performing the scan backlight driving method are described in Japanese Patent No. 5919992 and Japanese Patent No. 4540940. According to Japanese Patent No. 5919992, in order to control ghost in the liquid-crystal display apparatus performing the scan backlight driving method, the length of time from the completion of the writing on pixels to the emission of a corresponding area is nonlinearly varied in a scanning order of the areas while a time duration of the emission and an amount of light at the emission are varied in response to the location of each area. Japanese Patent No. 4540940 describes a backlight driver apparatus that, in scan backlight driving, adjusts a drive voltage and phase of a backlight during one frame period in response to the occurrence state of a block including a moving image and a sharp outline of the moving image during the one frame period. For example, a backlight including white-light LED with KSF phosphor is described in International Publication No. 2015/68513.
It is contemplated that a backlight including a white-light LED with KSF phosphor is used to improve the color reproducibility of backlight light in the liquid-crystal apparatus performing the flashing backlight driving or scan backlight driving. The flashing backlight driving and scan backlight driving are performed based on the premise that the backlight (or a backlight area) immediately switches from a light-emission state to a non-light-emission state.
The white-light LED with the KSF phosphor has the property that the afterglow of a red color persists longer than the afterglow of another color (such as of green or blue). If a liquid-crystal display apparatus performing the flash backlight driving or the scan backlight driving is implemented using the backlight including the white-light LED with the KSF phosphor, the red afterglow of the backlight light persists longer and a viewer visibly recognizes a video edge having a mixture of red color and cyan color.
In the liquid-crystal display apparatus with the backlight starting to emit light during a rewrite time, ghost is created on a display screen because of insufficient response time. The viewer visibly recognizes both a video edge with a mixture of red and cyan colors and ghost in the liquid-crystal display apparatus with the backlight including the white-light LED with the KSF phosphor starting to emit light during the rewrite time.
It is desirable to provide an image display apparatus and an image display method that preclude a viewer from visibly recognizing ghost and a video edge mixed with a particular color.
According to an aspect of the disclosure, there is provided an image display apparatus including: a display panel including multiple pixels; a backlight including multiple white-light light sources and emitting light onto a rear surface of the display panel; a panel driving circuit driving the display panel; a backlight driving circuit driving the backlight; and a determination circuit determining image data that is input. The white-light light sources have persistence characteristics that cause afterglow of a particular color to persist longer than afterglow of another color. The backlight driving circuit segments the backlight into multiple areas and drives the backlight in a manner such that a time duration of performing control to cause the areas to sequentially be in a light-emission state at mutually different timings alternates with a time duration of performing control to cause all the multiple areas to be in a non-light-emission state. The determination circuit determines a determination value indicating a degree of inclusion at which achromatic data is included in the image data and determines a light-emission start timing of each of the areas in accordance with the determination value.
According to another aspect of the disclosure, there is provided an image display method of an image display apparatus including a display panel including multiple pixels and a backlight including multiple white-light light sources and emitting light onto a rear surface of the display panel. The image display method includes: driving the display panel; driving the backlight; and determining image data that is input. The white-light light sources have persistence characteristics that cause afterglow of a particular color to persist longer than afterglow of another color. The driving of the backlight includes segmenting the backlight into multiple areas and driving the backlight in a manner such that a time duration of performing control to cause the areas to sequentially be in a light-emission state at mutually different timings alternates with a time duration of performing control to cause all the multiple areas to be in a non-light-emission state. The determining of the image data includes determining a determination value indicating a degree of inclusion at which achromatic data is included in the image data and determining a light-emission start timing of each of the areas in accordance with the determination value.
Image data D1 is input to the liquid-crystal display apparatus 1 from the outside. The image data converter 20 determines image data D3 by performing gradation conversion for overdrive on the image data D1. The image data converter 20 outputs to the display 10 light-emission start timings T1 and T2 and backlight data BLD, as drive data for the backlight 15. In response to the light-emission start timings T1 and T2 and backlight data BLD, the display 10 causes the backlight 15 to emit light while displaying an image on the liquid-crystal panel 14 in response to the image data D3.
The liquid-crystal panel 14 includes multiple pixels 16 that are two-dimensionally arranged. The backlight 15 includes multiple white-light light emitting diodes (LEDs) 17 serving as multiple white-light light sources. The backlight 15 further includes a light-guiding plate and the white-light LEDs 17 are one-dimensionally arranged along the side of the light-guiding plate. The backlight 15 is arranged on the backside of the liquid-crystal panel 14 and emits light on the rear surface of the liquid-crystal panel 14.
The timing control circuit 11 outputs a timing control signal TC to the panel driving circuit 12 and backlight driving circuit 13. The panel driving circuit 12 drives the liquid-crystal panel 14 in response to the timing control signal TC and image data D3. The panel driving circuit 12 sequentially writes image data included in the image data D3 on the pixels 16 on each row. The writing operation on the pixels 16 is performed from to top to bottom on a display screen. The backlight driving circuit 13 drives the backlight 15 in response to the timing control signal TC, light-emission start timings T1 and T2, and backlight data BLD. The backlight driving circuit 13 segments the backlight 15 into two areas and drives the two areas.
The image data D1 of one frame includes image data corresponding to the pixels 16 of the liquid-crystal panel 14. The determination circuit 21 sorts the image data into achromatic data and chromatic data. The determination circuit 21 determines whether a count of the achromatic data included in the image data D1 of one frame is higher than a threshold and outputs binary determination results RES. The memory 24 stores the determination results RES in the order of output. Based on latest M determination results RES stored on the memory 24 (M is 2 or a higher integer), the determination circuit 21 determines as a determination value X the ratio of frames, each frame having the count of the achromatic data higher than the threshold, to the latest M frame. The determination value X is 0 or higher and 1 or lower. The determination circuit 21 determines the light-emission start timings T1 and T2 of the backlight 15 in accordance with the determination value X.
The memory 25 stores beforehand two look-up tables (LUTs) for overdrive, 27a and 27b. The frame memory 23 stores the image data D1 of at least one frame. The gradation converting circuit 22 determines the image data D3 by performing gradation conversion for overdrive on the input image data D1 serving as image data of a current frame and image data D2 read from the frame memory 23 serving as image data of a preceding frame. The gradation conversion is performed using LUTs 27a and 27b stored on the memory 25.
The memory 26 stores beforehand the backlight data BLD used to determine the luminance of the backlight 15. The backlight data BLD includes a duty factor representing a ratio of light-emission time of the white-light LEDs 17 and a current value representing a current flowing through the white-light LEDs 17.
The liquid-crystal display apparatus 1 employs KSF phosphor as the red-light phosphor 32 to increase the color reproducibility of the backlight light (emission light from the backlight 15). Red light created using the KSF phosphor has the property that the afterglow persists longer. The white-light LED 17 employing the KSF phosphor thus has the property that the afterglow of the red light persists longer than the afterglow of the other colors (green and blue). After the backlight driving circuit 13 switches the first area from the light-emission state to the non-light-emission state, the afterglow of the red light of the backlight light persists longer in the first area. If the afterglow of the red light of the backlight light persists longer in the liquid-crystal display apparatus performing the scan backlight driving, the viewer visibly recognizes the video edge mixed with red and cyan colors.
To address this problem, the backlight driving circuit 13 drives the backlight 15 in a manner such that a time duration of performing control to cause the two areas to sequentially be in a light-emission state (hereinafter referred to as a partial light-emission duration) alternates with a time duration of performing control to cause all the two areas to be in a non-light-emission state (hereinafter referred to as an overall non-light-emission duration). In the following discussion, this driving is referred to as alternate scan backlight driving and an area count included in the backlight 15 is N. The area count N equals the number of partial light-emission durations within one frame period and equals the number of overall non-light-emission durations within one frame period. In the liquid-crystal display apparatus 1, N is 2.
The panel driving circuit 12 performs writing on the pixels 16 at the top row of the liquid-crystal panel 14 (a row corresponding to the top end of a display screen) at the start of the frame period. The panel driving circuit 12 then consecutively performs writing on the pixels 16 at the subsequent rows of the liquid-crystal panel 14. At the end of the frame period, the panel driving circuit 12 performs writing on the pixels 16 at the bottommost row of the liquid-crystal panel 14. In this way, the panel driving circuit 12 starts writing, at the beginning of the frame period, on the pixels 16 on the liquid-crystal panel 14 corresponding to the first area and starts writing, in the middle of the frame period, on the pixels 16 on the liquid-crystal panel 14 corresponding to the second area.
The backlight driving circuit 13 segments the backlight 15 into the first area and second area and causes each of the first area and second area to emit light once within one frame period in response to the light-emission start timings T1 and T2 determined by the determination circuit 21. Referring to
If the degree of inclusion at which the achromatic data is included in the image data D1 is higher (if the determination value X is higher), the viewer may be more likely to observe a video edge mixed with red and cyan colors. In this case, controlling coloring is more desirably prioritized. On the other hand, if the degree of inclusion at which the achromatic data is included in the image data D1 is lower (if the determination value X is lower), the viewer is less likely to observe the video edge mixed with red and cyan colors. In this case, improving the video display performance is more desirably prioritized.
The duration that the determination value X is higher than a predetermined value is referred to as a “coloring control priority duration.” The duration that the determination value X is lower than the predetermined value is referred to as a “video display performance priority duration.” The duration that the determination value X is at maximum (X=1) is referred to as a “coloring control top-priority duration.” The duration that the determination value X is at minimum (X=0) is referred to as a “video display performance top-priority duration.”
Let FT represent the length of one frame period, and light-emission start timings T1a and T2a are calculated to satisfy the following equation (1):
T2a−T1a=FT/2 (1)
Light-emission start timings T1b and T2b may be desirably determined in view of the response speed of the pixels. The light-emission start timings T1a, T2a, T1b, and T2b are determined to satisfy the following equation (2):
T2b−T1b<T2a−T1a. (2)
A difference between the light-emission start timing of the first area and the light-emission start timing of the second area with the first area and second area sequentially set to be in the light-emission state is higher during the coloring control top-priority duration than during the video display performance top-priority duration.
In accordance with the determination value X and the light-emission start timings T1a, T2a, T1b, and T2b, the determination circuit 21 determines the light-emission start timing T1 of the first area and the light-emission start timing T2 of the second area in view of the following equations (3) and (4) (with reference to
T1=X×T1a+(1−X)×T1b (3)
T2=X×T2a+(1−X)×T2b (4)
The determination circuit 21 determines the light-emission start timing T1 of the first area by dividing proportionally by the determination value X the light-emission start timing T1a of the coloring control top-priority duration of the first area and the light-emission start timing T1b of the video display performance top-priority duration of the first area. The determination circuit 21 furthermore determines the light-emission start timing T2 of the second area by proportionally dividing by the determination value X the light-emission start timing T2a of the coloring control top-priority duration of the second area and the light-emission start timing T2b of the video display performance top-priority duration of the second area.
As the determination value X is higher, the difference between the light-emission start timing T1 of the first area and the light-emission start timing T2 of the second area becomes larger when the first area and second area are sequentially set to be in the light-emission state. In this way, as the determination value X is higher, the determination circuit 21 causes to be larger a difference between the light-emission timings of multiple areas when the multiple areas are controlled to be subsequently in the light-emission state.
In step S102, the determination circuit 21 determines the light-emission start timings T1 and T2 in accordance with equations (3) and (4) in view of the determination value X and the light-emission start timings T1a, T2a, T1b, and T2b. The determination value X used in step S102 may be the value initialized in step S101 or determined in step S109.
The determination circuit 21 outputs the determination value X and light-emission start timings T1 and T2 determined in step S102 (step S103). The determination value X is output to the gradation converting circuit 22 and is used by the gradation converting circuit 22 in gradation conversion. The light-emission start timings T1 and T2 are output to the backlight driving circuit 13 and is used by the backlight driving circuit 13 when the backlight driving circuit 13 drives the backlight 15.
The determination circuit 21 determines a count CNT of achromatic data included in the image data D1 of one frame (step S104). In accordance with a predetermined criteria, the determination circuit 21 sorts the image data included in the image data D1 into achromatic data and chromatic data. For example, the determination circuit 21 may sort, into the achromatic data, the image data including a red component, a green component, and a blue component, all equal to each other. Alternatively, the determination circuit 21 may sort, into achromatic data, the image data including a red component, a green component, and a blue component with a difference therebetween lower than a predetermined value.
The determination circuit 21 determines whether the count CNT is higher than a threshold TH (step S105). If yes path is followed, processing proceeds to step S106 and if no path is followed, processing proceeds to step S107. In step S106, the determination circuit 21 sets the determination results RES to 1. In step S107, the determination circuit 21 sets the determination results RES to 0. The determination circuit 21 writes the determination results RES set in step S106 or S107 onto the memory 24 (step S108).
The determination circuit 21 determines the determination value X by dividing a sum of latest M determination results RES stored on the memory 24 by the number M of frames (step S109). The determination value X represents a ratio of fames, each having the count CNT of the achromatic data higher than the threshold TH, to the latest M frames. The determination circuit 21 returns to step S102. The determination value X determined in step S109 is used when the light-emission start timings T1 and T2 are determined next in step S102.
Instead of determining the count CNT of the achromatic data included in the image data D1 of one frame in step S104, the determination circuit 21 may select multiple pieces of representative image data from the image data D1 of one frame and determine the count of the achromatic data out of the representative image data. Instead of dividing the sum of M latest determination results RES by the number M of frames (namely, instead of performing simple averaging of M latest determination results RES) in step S109, the determination circuit 21 may weighted-average M determination results RES with a larger weight applied to a later result RES.
The determination circuit 21 determines the determination value X in accordance with the M determination results RES related to the image data D1 of M frames. In this way, a sharp change in the determination value X may thus be controlled. The number M of frames may be set to within a range from several frames to several hundreds of frames in view of image discomfort occurring on the display screen.
If the threshold TH is set to 0, and if at least a single piece of the achromatic data is included in the image data D1 of one frame, then the determination results RES is 1. For this reason, the determination value X is 1 in many cases and the light-emission timings T1 and T2 respectively become closer to light-emission timings T1a and T2a (
Referring to
The gradation conversion for overdrive to be performed by the image data converter 20 is described below. As previously described, the memory 25 pre-stores two LUTs 27a and 27b for overdrive. The LUTs 27a and 27b store post-conversion-gradation values corresponding to combinations of a gradation value of a current frame and a gradation value of a preceding frame. The LUT 27a stores a post-conversion-gradation value during the coloring control top-priority duration and the LUT 27b stores a post-conversion-gradation value during the video display performance top-priority duration. The post-conversion-gradation value during the coloring control top-priority duration emphasizes more a time change of the image data D1 than the post-conversion-gradation value during the video display performance top-priority duration.
As previously described, the gradation converting circuit 22 determines the image data D3 by performing the gradation conversion for overdrive on the input image data D1 serving as the image data of the current frame and the image data D2 read from the frame memory 23 serving as the image data of the preceding frame. Let d1, d2, and d3 respectively represent gradation values of color components of the image data included in the image data D1, D2, and D3. The gradation converting circuit 22 reads a gradation value d3a responsive to the gradation values d1 and d2 from the LUT 27a and a gradation value d3b responsive to the gradation values d1 and d2 from the LUT 27b. The gradation converting circuit 22 determines the gradation value d3 in accordance with equation (5) in view of the determination value X determined by the determination circuit 21 and the gradation values d3a and d3b:
d3=X×d3a+(1−X)×d3b (5)
As the degree of inclusion at which the achromatic data is included in the image data D1 is higher (specifically, as the determination value X is higher, namely, coloring is to be controlled with higher priority), the degree of emphasis on the time change of the image data D1 (the degree of overdrive) is higher. On the other hand, as the degree of inclusion at which the achromatic data is included in the image data D1 is lower (specifically, as the determination value X is lower, namely, display performance is to be improved with higher priority), the degree of emphasis on the time change of the image data D1 is lower. By switching the degree of overdrive appropriately in response to the determination value X in this manner, an insufficiency of the response speed of the liquid-crystal panel 14 may thus be reduced.
A comparative liquid-crystal display apparatus (
The border portion between the two areas looks gray to the viewer. A portion having a red component at a higher quantity looks mixed with red to the viewer. A portion having green and blue components at a higher quantity looks mixed with cyan to the viewer.
Looking at the display screen of the comparative liquid-crystal display apparatus, the viewer views ghost occurring in response to the degree of response insufficiency and ghost occurring in response to the number of light emissions during one frame period. Let P represent the number of ghosts responsive to the degree of response insufficiency and N, the number of areas, and the number of visible ghosts is (N−1+P). Since a difference between the red component and the green component and a difference between the red component and the blue component increase in a video blur region (a region changing from dark to white), the viewer visibly recognizes red and cyan, higher in chroma, with respect to an achromatic edge.
In contrast, as the number of ghosts (namely, N−1+P) is higher in the liquid-crystal display apparatus 1, a difference between a video blur waveform of a red color and a video blur waveform of another color becomes smaller. Where the viewer visibly recognizes the video edge, red, green, and blue changes at a higher frequency. The liquid-crystal display apparatus 1 may thus preclude the viewer from visibly recognizing the video edge mixed with red and cyan.
As the number of ghosts is higher, the liquid-crystal display apparatus 1 may provide more the effect of precluding the viewer from visibly recognizing the video edge mixed with red and cyan. On the other hand, if the number of ghosts increases, the effect of increasing video display performance is reduced. To achieve a balance between the two effects, the number N of areas is set to 2 and the backlight 15 may be configured to reduce the intensity of light of one area while diffusing the light to the far end of another area.
The backlight 15 is driven in a manner such that controlling of the coloring is prioritized in an image including a larger amount of achromatic data and having noticeable coloring. The backlight 15 is also driven in a manner such that improvement of the video display performance is prioritized in an image including a large amount of chromatic data and having less noticeable coloring. The liquid-crystal display apparatus 1 switches, in response to the characteristics of the image data D1, between placing priority on controlling of the coloring and placing priority on improvement of the video display performance. The viewer may thus be precluded from visibly recognizing the ghost and the video edge mixed with a particular color. The determination circuit 21 performs the process in
The image data converter 20 may be implemented in any method in view of the configuration of the liquid-crystal display apparatus 1. For example, each of the determination circuit 21 and gradation converting circuit 22 may be implemented using a dedicated circuit. Alternatively, the determination circuit 21 and/or the gradation converting circuit 22 may be implemented using a combination of a central processing unit (CPU) and a computer program executed by the CPU. The memories 24 through 26 may be implemented by a single memory.
As previously described, the image display apparatus of the embodiment (the liquid-crystal display apparatus 1) includes the display panel (the liquid-crystal panel 14) including the multiple pixels 16, the backlight 15 including multiple white-light light sources (white-light LEDs 17) and emitting light to the rear surface of the display panel, the panel driving circuit 12 driving the display panel, the backlight driving circuit 13 driving the backlight 15, and the determination circuit 21 determining the image data D1 that is input. The white-light LED has the property that the afterglow of a particular color (such as red) persists longer than the afterglow of another color (such as green or blue). The backlight driving circuit 13 segments the backlight 15 into multiple areas (the first area and second area) and drives the backlight 15 in a manner such that a time duration of performing control to cause the areas to sequentially be in the light-emission state at mutually different timings (partial light-emission duration) alternates with a time duration of performing control to cause all the multiple areas to be in a non-light-emission state (overall non-light-emission duration). The determination circuit 21 determines the determination value X indicative of the degree of inclusion at which the achromatic data is included in the image data D1 and determines the light-emission start timings T1 and T2 of the areas in accordance with the determination value X.
In the image display apparatus of the embodiment, when the afterglow of the particular color of the backlight light persists longer, the backlight 15 is controlled such that the time duration of performing control to cause the areas to sequentially be in the light-emission state alternates with the time duration of performing control to cause all the areas to be in the non-light-emission state. The difference between the video blur waveform of the particular color and the video blur waveform of another color may be reduced, precluding the viewer from visibly recognizing the video edge mixed with the particular color. The image display apparatus determines the determination value X indicative of the degree of inclusion at which the achromatic data is included in the image data D1 and determines the light-emission start timings T1 and T2 of the areas of the backlight 15 in accordance with the determination value X. The image display apparatus thus switches, in response to the characteristics of the image data D1, between placing priority on controlling of the coloring and placing priority on improvement of the video display performance. The viewer may thus be precluded from visibly recognizing the ghost and the video edge mixed with the particular color.
The determination circuit 21 calculates the count CNT of the achromatic data included in the image data D1 of one frame and calculates as the determination value X the ratio of frames, each frame having the count CNT higher than the threshold TH, to the latest frames (M frames). In this way, the determination circuit 21 may determine the determination value X indicative of the degree of inclusion at which the achromatic data is included in the image data D1. As the determination value X is higher, the determination circuit 21 increases the difference between the light-emission start timings T1 and T2 of the areas when the areas are sequentially controlled to the light-emission state. The determination circuit 21 thus switches, in response to the characteristics of the image data D1, between placing priority on controlling of the coloring and placing priority on improvement of the video display performance. The viewer may thus be precluded from visibly recognizing the ghost and the video edge mixed with the particular color.
The backlight driving circuit 13 segments the backlight 15 into the first and second areas. The determination circuit 21 determines the light-emission start timing T1 of the first area by dividing by the determination value X the light-emission start timing T1a of the first area with the determination value X at maximum (X=1) and the light-emission start timing T1b of the first area with the determination value X at minimum (X=0). The determination circuit 21 also determines the light-emission start timing T2 of the second area by dividing by the determination value X the light-emission start timing T2a of the second area with the determination value X at maximum and the light-emission start timing T2b of the second area with the determination value X at minimum. In this way, when the backlight 15 is segmented into the two areas, the light-emission timings of the areas may be easily determined.
The image display apparatus further includes the gradation converting circuit 22 that performs gradation conversion for overdrive on the image data D1. In response to the determination value X, the gradation converting circuit 22 varies the degree of emphasis on the time change of the image data D1 in response to the determination value X. The gradation converting circuit 22 increases the degree of emphasis on the time change of the image data D1 as the determination value X is higher. In this way, the degree of emphasis on the time change of the image data D1 is appropriately switched in response to the degree of inclusion at which the achromatic data is included in the image data D1. The white-light light source is the white-light LED 17 including the blue-light LED 31, red-light phosphor 32, and green-light phosphor 33. The red-light phosphor 32 is the KSF phosphor.
The liquid-crystal display apparatus 1 of the embodiment may be modified. In the liquid-crystal display apparatus 1, the white-light light source included in the liquid-crystal panel 14 has the property that the afterglow of a red color persists longer than the afterglow of another color. In a modification of the liquid-crystal display apparatus, the white-light light source in the backlight may have the property that the afterglow of a green color persists longer than the afterglow of other colors (red and blue) or the afterglow of a blue color persists longer than the afterglow of other colors (red and green). The backlight 15 in the liquid-crystal display apparatus 1 includes multiple white-light LEDs 17 one-dimensionally arranged along the side of a light guide plate. Another modification of the liquid-crystal display apparatus may include the backlight including multiple white-light LEDs 17 and may have any configuration as long as the two areas are individually controlled. For example, the backlight may include multiple white-light LEDs 17 that are arranged two-dimensionally.
In the liquid-crystal display apparatus 1, the backlight driving circuit 13 performs two-segment alternate scan backlight driving. In one modification of the liquid-crystal display apparatus 1, the backlight driving circuit may perform N-segment alternate scan backlight driving (N is 3 or higher integer). Such modification may provide the same effect as the liquid-crystal display apparatus 1. Not only the liquid-crystal display apparatus including the backlight but also an image display apparatus may be implemented in a way similar to the way described above.
The present disclosure contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2020-204932 filed in the Japan Patent Office on Dec. 10, 2020, the entire contents of which are hereby incorporated by reference.
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-204932 | Dec 2020 | JP | national |
