TOKKAT 2002-116728
`
`(2) Unexamined Patent Application (KOKAT) Publication (A)
`(19) Japanese Patent Office (JP)
`(11) Patent Application Filing Number
`TOKKAI 2002-116728
`(P2002-116728A)
`(43) KOKAI Date: April 19, 2002
`
`(51) Int. Ch’
`GO09G 3/20
`
`LD. Symbol
`642
`611
`641
`
`3/22
`3/28
`
`FI
`GO09G 3/20
`
`3/22
`3/30
`
`642
`oll
`641
`
`Topic code (reference)
`P 5C058
`A 5C080
`O
`E
`K
`
`Examination Request State: Not requested Number of Claims: 13 (Total 18 pages)
`continued on last page
`
`(21) Application No.
`
`Pat. Application 2000-308766 (P200-308766)
`
`(22) Filing Date
`
`October 10, 2000
`
`(71) Applicant
`
`(72) Inventor
`
`(72) Inventor
`
`(74) Agent
`
`000005821
`Matsuda Denki Sangyo Corp (Panasonic Corp)
`No. 1006 Kadoma, Kadoma-shi, Osaka Prefecture
`Masanobu Inoe
`c/o Matsuda Denki Sangyo Corp
`No. 1006 Kadoma, Kadoma-shi, Osaka Prefecture
`Takahiro Kobayashi
`c/o Matsuda Denki Sangyo Corp
`No. 1006 Kadoma, Kadoma-shi, Osaka Prefecture
`100097445
`Fumio Iwabashi, patent attorney (and twoothers)
`
`continued on last page
`
`(54) Title of Invention: Display Device
`
`(57) Abstract
`Problem: To provide a display device wherewith, when performing an imagedisplay on a
`display unit configured by self-emitting devices, both low-power operation and display
`quality deterioration suppression are possible.
`Meansfor Resolution: A display unit 4 is configured of a plurality of signal lines, a
`plurality of scanning lines, TFTs (thin-filmtransistors) provided for every pixel, and self-
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`TOKKAT 2002-116728
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`emitting devices and the like. Average brightness detection means 5 detect the average
`brightness (APL [averagepicture level]) in a video signal. The APLis detected for either
`one screen or in multiple screen units. Gradient gain generation means 6 generate a gradient
`gain in correspondence with the APL. When the APLis high, the gradient gainis set large,
`and when the APL ts low, the gradient gain is set small. Signal level adjustment means 7
`lower the level of a video signal in correspondence with the gradient gain toward the
`periphery, centered on a prescribed position on the screen.
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`TOKKAT 2002-116728
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`Patent Claims
`Claim |. A display device for displaying an input video signal on a display unit configured
`by auto-emitting devices; comprising:
`signal-side drive means for driving a plurality of signal lines in said display unit;
`scanning-side drive meansfor driving a plurality of scanning lines in said display unit;
`a controller for controlling said signal-side drive means and said scanning-side control
`means;
`average brightness detection means for detecting the average brightness level (APL) in
`said video signal;
`gradient gain generation means for outputting a signal gradient gain in correspondence
`with said APL; and
`signal level adjustment means for changingthe signal level in correspondence with said
`signal gradient gain.
`Claim 2. The display device according to claim 1, wherein: the gradient gain generation
`meansset said signal gradient gain large when said APLis high, and set said signal
`gradient gain small when said APL is low; and the signal level adjustment means change
`the signal level so that it falls, toward the outside as centered on a prescribed position on
`the display screen, in correspondence with said signal gradient gain.
`Claim 3. A display device for displaying an input video signal on a display unit configured
`by auto-emitting devices; comprising:
`average brightness detection means for detecting the average brightness level (APL) in
`said video signal;
`gradient gain generation means for making the signal gradient gain large when said
`APLis high, and making the signal gradient gain small when said APLis low;
`horizontal signal level adjustment means for changing the signal level in
`correspondence with said signal gradient gain;
`gate width adjustment means for changing the gate width that drives the scanning lines
`in the interior of the display in correspondence with said signal gradient gain;
`signal-side drive meansfor driving a plurality of signal lines in said display unit;
`scanning-side drive meansfor driving a plurality of scanninglines in said display unit;
`
`and
`
`a gate width correspondence controller for controlling said signal-side drive means and
`said scanning-side drive means in correspondence with the output of said gate width
`adjustment means.
`Claim 4. The display device according to claim 3, wherein: the horizontal signal level
`adjustment means lowerthe signal level in correspondence with said signal gradient gain
`toward the left and right in the horizontal direction, centered on a prescribed position on the
`display screen; and the gate width adjustment means change the gate widththat drives the
`scanning lines in the interior of the display, up and down in the vertical direction, centered
`of a prescribed position on the display screen, so that that gate width becomesshorter, in
`correspondence with said signal gradient gain.
`Claim 5. A display device for displaying an input video signal on a display unit configured
`by auto-emitting devices; comprising:
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`TOKKAT 2002-116728
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`horizontal-side drive means for driving a plurality of signal lines and device power
`supply voltage in said display unit;
`scanning-side drive meansfor driving a plurality of scanninglines in said display unit;
`a controller for controlling said horizontal-side drive means and said scanning-side
`drive means;
`average brightness detection means for detecting the average brightness level (APL) of
`said video signal;
`gradient gain generation means for making the signal gradient gain large whensaid
`APLis high, and makingthe signal gradient gain small whensaid APLis low;
`device powersupply voltage adjustment means for changing the power supply voltage
`supplied to light emitting devices in the interior of the display in correspondence withsaid
`signal gradient gain; and
`vertical signal level adjustment means for changing the signal level in correspondence
`with said signal gradient gain.
`Claim 6. The display device according to claim 5, wherein: the device power supply
`voltage adjustment means lower the power supply voltage supplied to light emitting
`devices in the interior of the display, toward the left right in the horizontal direction,
`centered on a prescribed position on the display screen, in correspondencewith said signal
`gradient gain; and said vertical signal level adjustment means lowerthe signal level up and
`downin the vertical direction, centered on a prescribed position on the display screen, in
`correspondence with said signal gradient gain.
`Claim 7. A display device for displaying an input video signal on a display unit configured
`by auto-emitting devices; comprising:
`average brightness detection means for detecting the average brightness level (APL) in
`said video signal;
`gradient gain generation means for making the signal gradient gain large when said
`APLis high, and making the signal gradient gain small when said APLis low;
`device power supply voltage adjustment means for changing the power supply voltage
`supplied to light emitting devices, toward the left and right in the horizontal direction,
`centered on a prescribed position on the display screen;
`gate width adjustment means for shortening the gate width that drives the scanning lines
`in the interior of the display, up and downinthe vertical direction, centered on a prescribed
`position on the display screen, in correspondence with said signal gradient gain;
`horizontal-side drive means for driving a plurality of signal lines and device power
`supply voltage in said display unit;
`scanning-side drive meansfor driving a plurality of scanninglines in said display unit;
`
`and
`
`a gate width correspondence controller for controlling said horizontal-side drive means
`and said scanning-side drive means, in correspondence with the output of said gate width
`adjustment means.
`Claim 8. A display device for displaying an input video signal on a display unit configured
`by auto-emitting devices; comprising:
`signal-side drive means for driving a plurality of signal lines in said display unit;
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`TOKKAT 2002-116728
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`scanning-side drive meansfor driving a plurality of scanning lines in the interior of said
`display unit;
`a controller for controlling said signal-side drive means and said scanning-side drive
`means;
`average brightness detection means for detecting the average brightness level (APL) in
`said video signal;
`maximum brightness position detection means for detecting the maximum brightness
`position (MAXP)in said video signal;
`gradient gain generation means for making the signal gradient gain large whensaid
`APLis high, and makingthe signal gradient gain small when said APL is low; and
`signal level adjustment means for lowering the signal level toward the outside, centered
`on MAXP, in correspondence with said signal gradient gain.
`Claim 9. A display device for displaying an input video signal on a display unit
`configured by auto-emitting devices; comprising:
`average brightness detection means for detecting the average brightness level (APL) in
`said video signal;
`gamma gain generation means for changing the signal gamma gain in correspondence
`with said APL;
`gammaadjustment means for changing the signal gamma in correspondencewithsaid
`signal gammagain;
`maximum signal detection means for detecting the maximum signal level output by said
`gamma adjustment means;
`output stage voltage adjustment means for outputting a control value in correspondence
`with said maximumsignallevel;
`signal-side drive means for changing the output stage power supply voltage in
`correspondence with the output of said output stage voltage adjustment means, and driving
`a plurality of signal lines in said display unit;
`scanning-side drive means for driving a plurality of scanning linesin said display unit;
`
`and
`
`a controller for controlling said signal-side drive means and said scanning-side drive
`means.
`Claim 10. The display device according to claim 9, wherein: the gamma gain generation
`meansset the signal gammagain small when said APLis high, and set the signal gamma
`gain large when said APLis low; and the output stage voltage adjustment means output a
`control value for changing the output stage power supply voltage of said signal-side drive
`meansto the minimum necessary level in correspondence with up-and-down movements of
`said maximumsignal level.
`Claim 11. The display device according to any one of claims 1, 3, 5, 7, and 8, wherein the
`gradient gain generation means change the signal gradient gain either linearly or
`parabolically.
`Claim 12. The display device accordingto any one of claims 1, 3, 5, 7, 8, and 9, wherein
`the display unit is configured of organic Electrodes, LEDs,electrical discharge tube(s), or
`electronic discharge device(s).
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`TOKKAT 2002-116728
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`Claim 13. The display device according to claim 3 or 7, wherein the gate width adjustment
`means are built into the gate width correspondence controller.
`Detailed Description of Invention
`[0001]
`Technical Field to Which Invention Belongs: This inventionrelates to a display device
`configured by auto-emitting devices that control the display signal level in correspondence
`with the characteristics of the input video signal, with the object of reducing electrical
`power consumption and enhancing display quality.
`[0002]
`In the past, various configurations have been proposed for reducing power
`Prior Art:
`consumption in display devices. A conventional configuration for a display device wherein
`lower power operation is sought is diagrammed in Fig. 24. In Fig. 24, average brightness
`detection means 5 output the average brightness level (hereinafter “APL”) of the video
`signal. Contrast adjustment means 20 changethe contrast gain for the video signal in
`correspondence with the APL. A controller 1 inputs a video synchronization signal and
`outputs control signals for scanning-side drive means 2 and signal-side drive means 3. The
`signal-side drive means 3 output a signal in correspondence with the video signal to a
`signal line in the display unit 4. The scanning-side drive means 2 output a signal to a
`scanning line in the display unit 4. The display unit 4 is a matrix-form display unit wherein
`a plurality of signal lines and a plurality of scanning lines are combined.
`[0003] In Fig. 25, the internal configuration of the display unit 4 is diagrammed.In Fig.
`25, the scanning-side drive means 2 output a signal for turning ON the gate ofa first TFT
`50 for a scanning line. The first TFT 50, while the gate is ON, accumulates electric
`potentials on the signal line(s) that are outputs from the signal-side drive means 3. The
`current flowing through a second TFT 52 is determined in correspondence with the charge
`accumulated in a capacitance 51, and an auto-emitting device 52 [sic] emits light.
`[0004] In Fig. 26, the internal configuration of the signal-side drive means 3 is
`diagrammed. In Fig. 26, data signal holding means 55 effect image data holding by a data
`holding timing signal from data processing means 56. The signal from the data signal
`holding means 55 is output, via data signal output means 54, to the signal line(s) of the
`display unit.
`[0005] In Fig. 27, the internal configuration of the scanning-side drive means2 is
`diagrammed. In Fig. 27, level conversion means 58 perform level conversion on a signal
`from scanning signal control means 59 which are configured by (a) shift register(s), and
`output a signal to scanning signal output means 57.
`[0006] In Fig. 28, the internal configuration of the controller 1 is diagrammed.In Fig. 28,
`control signals from display control means 62 are output to horizontal signal supply means
`60 and vertical signal supply means 61. The horizontal signal supply means 60 produce
`horizontal signals such as horizontal shift clock signals, horizontal start signals, and
`horizontal output enable signals, and output them to signal-side drive means. The vertical
`signal supply means 61 produce vertical signals such as scanning shift clock signals,
`scanning start signals, and scanning output enable signals, and output them to scanning-side
`drive means.
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`TOKKAT 2002-116728
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`[0007] In Fig. 29, a drive waveform timing chart is diagrammed.In Fig. 29, signal data in
`1-line units on the signal line(s) are output to the signal line output every | horizontal
`period. On the scanning-line output side, a signal for turning the correspondingline gate
`ONis output, synchronized with the signal line output data.
`[0008] In Fig. 30, the processing states of the contrast adjustment means 20 are
`diagrammed. In Fig. 30, APL is plotted on the horizontal axis, while contrast gain is plotted
`on the vertical axis. When the APL is high, the contrast gain is controlled so as to decline.
`In this manner, when the average brightness level rises and the overall screen power
`consumption becomeslarge, the contrast gain is lowered in order to lower the overall
`screen brightness and thus suppress power.
`[0009]
`Problems Invention Would Resolve: However, in the conventional configuration
`diagrammedin Fig. 24, when the APLis high, the overall screen brightness will be lowered.
`uniformly, which will lead to a decline in display quality due to the change in contrast.
`[0010] An object of the present invention, in view of the points noted above,is to provide
`a display device wherewith low power operation and display quality degradation
`suppression are possible when effecting image displays on a display unit configured by
`auto-emitting devices.
`[0011]
`In order to attain the object noted above, the invention
`Meansfor Resolving Problems:
`described in claim 1 of this application is a display device for displaying an input video
`signal on a display unit configured by auto-emitting devices that comprises average
`brightness detection means for detecting the average brightness level (APL) in the video
`signal, gradient gain generation means for outputting a signal gradient gain in
`correspondence with the APL, signal level adjustment means for changing the signal level
`in correspondence with the signal gradient gain, signal-side drive means for driving a
`plurality of signal lines in the display unit, scanning-side drive meansfor driving a plurality
`of scanning lines in the display unit, and a controller for controlling the signal-side drive
`means and the scanning-side drive means.
`[0012] The invention described in claim 2, moreover,is the display device described in
`claim 1, wherein the gradient gain generation meansset the signal gradient gain large when
`the APLis high, and set the signal gradient gain small when the APL is low,and the signal
`level adjustment means changethe signal level so that it falls, toward the outside as
`centered on a prescribed position on the display screen, in correspondence with the signal
`gradient gain.
`[0013] The invention described in claim 3, moreover, is a display device for displaying an
`input video signal on a display unit configured by auto-emitting devices that comprises
`average brightness detection means for detecting the average brightness level (APL)in the
`video signal, gradient gain generation means for making the signal gradient gain large when
`the APL is high, and makingthe signal gradient gain small when the APLis low, horizontal
`signal level adjustment means for changingthe signal level in correspondence with the
`signal gradient gain, gate width adjustment means for changing the gate width that drives
`the scanning lines in the interior of the display in correspondence with the signal gradient
`gain, signal-side drive meansfor driving a plurality of signal lines in the display unit,
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`TOKKAT 2002-116728
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`scanning-side drive means for driving a plurality of scanning lines in the display unit, and a
`gate width correspondence controller for controlling the signal-side drive means and the
`scanning-side drive means in correspondence with the output of the gate width adjustment
`means.
`[0014] The invention described in claim 4, moreover, is the display device described in
`claim 3, wherein the horizontal signal level adjustment means lowerthe signal level in
`correspondencewith the signal gradient gain toward the left and right in the horizontal
`direction, centered on a prescribed position on the display screen, and the gate width
`adjustment means change the gate width that drives the scanninglines in the interior of the
`display, up and downin the vertical direction, centered of a prescribed position on the
`display screen, so that that gate width becomesshorter, in correspondencewith the signal
`gradient gain.
`[0015] The invention described in claim 5, moreover,is a display device for displaying an
`input video signal on a display unit configured by auto-emitting devices, which comprises
`average brightness detection means for detecting the average brightness level (APL) of the
`video signal, gradient gain generation means for making the signal gradient gain large when
`the APL is high, and makingthe signal gradient gain small when the APL is low, device
`powersupply voltage adjustment means for changing the power supply voltage supplied to
`light emitting devices in the interior of the display in correspondence with the signal
`gradient gain, vertical signal level adjustment means for changingthe signal level in
`correspondence with the signal gradient gain, horizontal-side drive means for driving a
`plurality of signal lines and device power supply voltage in the display unit, scanning-side
`drive means for driving a plurality of scanning lines in the display unit, and a controller for
`controlling the horizontal-side drive means and the scanning-side drive means.
`[0016] The invention described in claim 6, moreover, is the display device described in
`claim 5, wherein the device power supply voltage adjustment means lower the power
`supply voltage supplied to light emitting devices in the interior of the display, toward the
`left right in the horizontal direction, centered on a prescribed position on the display screen,
`in correspondence with the signal gradient gain, and the vertical signal level adjustment
`means lower the signal level up and downin the vertical direction, centered on a prescribed
`position on the display screen, in correspondence with the signal gradient gain.
`[0017] The invention described in claim 7, moreover, is a display device for displaying an
`input video signal on a display unit configured by auto-emitting devices, that comprises
`average brightness detection means for detecting the average brightness level (APL) in the
`video signal, gradient gain generation means for making the signal gradient gain large when
`the APL is high, and making the signal gradient gain small when the APL is low, device
`powersupply voltage adjustment means for changing the power supply voltage supplied to
`light emitting devices, toward the left and right in the horizontal direction, centered on a
`prescribed position on the display screen, gate width adjustment means for shortening the
`gate width that drives the scanning lines in the interior of the display, up and downin the
`vertical direction, centered on a prescribed position on the display screen, in
`correspondence with the signal gradient gain, horizontal-side drive means for driving a
`plurality of signal lines and device power supply voltage in the display unit, scanning-side
`drive means for driving a plurality of scanning lines in the display unit, and a gate width
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`TOKKAT 2002-116728
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`correspondence controller for controlling the horizontal-side drive means and the scanning-
`side drive means, in correspondence with the output of the gate width adjustment means.
`[0018] The invention described in claim 8, moreover,is a display device for displaying an
`input video signal on a display unit configured by auto-emitting devices, that comprises
`average brightness detection means for detecting the average brightness level (APL)in the
`video signal, maximum brightness position detection means for detecting the maximum
`brightness position (MAXP)in the video signal, gradient gain generation means for making
`the signal gradient gain large when the APL is high, and making the signal gradient gain
`small when the APLis low, signal level adjustment means for loweringthe signal level
`toward the outside, centered on MAXP,in correspondence with the signal gradient gain,
`signal-side drive means for driving a plurality of signal lines in the display unit, scanning-
`side drive meansfor driving a plurality of scanning lines in the interior of the display unit,
`and a controller for controlling the signal-side drive means and the scanning-side drive
`means.
`
`[0019] The invention described in claim 9, moreover, is a display device for displaying an
`input video signal on a display unit configured by auto-emitting devices, that comprises
`average brightness detection means for detecting the average brightness level (APL)in said
`video signal, gamma gain generation means for changing the signal gammagain in
`correspondence with said APL, gamma adjustment means for changing the signal gamma
`in correspondence with said signal gamma gain, maximum signal detection means for
`detecting the max signal level output by said gamma adjustment means, output stage
`voltage adjustment means for outputting a control value in correspondence with said
`maximum signal level, signal-side drive means for changing the output stage power supply
`voltage in correspondence with the output of said output stage voltage adjustment means,
`and driving a plurality of signal lines in said display unit, scanning-side drive means for
`driving a plurality of scanning lines in said display unit, and a controller for controlling said
`signal-side drive means and said scanning-side drive means.
`[0020] The invention described in claim 10, moreover, is the display device described in
`claim 9, wherein the gamma gain generation meansset the signal gamma gain small when
`the APL is high, and set the signal gamma gain large when the APL is low, and the output
`stage voltage adjustment means outputs a control value for changing the output stage power
`supply voltage of the signal-side drive means to the minim necessary level in
`correspondence with up-and-down movements of the maximum signallevel.
`[0021] The invention described in claim 11, moreover, is the display device according to
`any one of claims 1, 3, 4,5, 7, and 8, wherein the gradient gain generation means change
`the signal gradient gain either linearly or parabolically.
`[0022] The invention described in claim 12, moreover, is the display device according to
`any one of claims 1, 3, 5, 7, 8, and 9, wherein the display unit is configured of organic
`Electrodes, LEDs, electrical discharge tube(s), or electronic discharge device(s).
`[0023] The invention described in claim 13, moreover, is the display device according to
`claim 3 or 7, wherein the gate width adjustment means are built into the gate width
`correspondence controller.
`[0024]
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`TOKKAT 2002-116728
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`Preferred Embodiments of Invention: Embodiments of the present invention are now
`described with reference to the drawings.
`[0025] (Embodiment 1) Fig. 1 is a block diagramof the configuration of a display device
`for displaying input video signals on a display unit configured by auto-emitting devices, in
`Embodiment | of the present invention. In Fig. 1, the display unit 4 1s configured by a
`plurality of signal lines, a plurality of scanning lines, TFTs (thin film transistors) provided
`for every pixel, and auto-emitting devices or the like. The internal configuration of the
`display unit 4 is as diagrammed in Fig. 25. Signal-side drive means 3, scanning-side drive
`means 2, and the controller | are the same as diagrammed for a conventional example in
`Figs. 26, 27, and 28. Average brightness detection means 5 detect the APL of video signals.
`The APLis detected either for one screen or in multiple screen units. Gradient gain
`generation means 6 generate a gradient gain in correspondence with the APL. When the
`APLis high, the gradient gain is set large, and when the APL is low,the gradient gainis set
`small. Signal level adjustment means 7 change the video signal level in correspondence
`with the gradient gain.
`[0026] In Fig. 2 is diagrammedthe internal configuration of the signal level adjustment
`means 7. In Fig. 2, a gradient processor 64 outputs a control value for changing the video
`signal level in correspondence with the gradient gain. A position is set as the center position
`where processing is performed. An arithmetic processor 63 performs video signal level
`conversion processing in correspondence with the output from the gradient processor 64.
`The output of the arithmetic processor 63 is sent to signal-side drive means via an output
`unit.
`[0027] In Fig. 3, the relationship between gradient gain and APL in the gradient gain
`generation means6 is plotted. As indicated in Fig. 3, when the APLis low,the gradient
`gain is set low (the gradient is small), and when APLis high, the gradient gain is set large
`(the gradient is large). In Fig. 3, moreover, the example ofa linear change is represented,
`but that change may be parabolic.
`[0028] In Fig. 4, the gradient gain states are diagrammed. In Fig. 4, 100% meansthat the
`video signal level is displayed as is, while 90% meansthat the video signal is displayed
`with the level thereof lowered to 90%. In Fig. 4, the center of the screenis taken as the
`center of gradient gain processing. As diagrammedin Fig. 4, when the APLis high, the
`gain for the video signal goes down with a large gradient, from the center toward the
`periphery. When the APL is low, on the other hand, the difference between the gain at the
`center and at the periphery is set small. In Fig. 4, furthermore, an example of a parabolic
`change is diagrammed, but that change maybe linear. Also, the gain values in Fig. 4
`represent one example, and these values can change depending on the system.
`[0029] By lowering the signal level from a prescribed center position on the screen toward
`the periphery, in this manner, the currents flowing to the auto-emitting devices configuring
`the pixels in the display unit are comprehensively suppressed. Because the gradient gain is
`set in correspondence with the APL, whenthe overall screen is bright, that is, the larger the
`power consumption, the more will the power suppression effect be exhibited. Visually,
`because the gain is gradually lowered toward the periphery, no pronounced decline in
`display quality occurs.
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`TOKKAT 2002-116728
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`[0030] (Embodiment 2) Fig. 5 is a block diagram of the configuration of a display device
`for displaying input video signals on a display unit configured by auto-emitting devices, in
`Embodiment2 of the present invention. In Fig. 5, the display unit 4 is configured by a
`plurality of signal lines, a plurality of scanning lines, TFTs (thin film transistors) provided
`for every pixel, and auto-emitting devices or the like. The internal configuration of the
`display unit 4 is the same as diagrammedin Fig. 25. The signal-side drive means 3 and
`scanning-side drive means 2 are the same as indicated for the conventional example in Figs.
`26 and 27. The average brightness detection means 5 detect the APL of video signals. The
`APLis detected either for one screen or in multiple screen units. The gradient gain
`generation means 6 generate a gradient gain in correspondence with the APL. Whenthe
`APLis high, the gradient gain is set large, and when the APL is low, the gradient gain is set
`small. The processing performed by the gradient gain generation means6 is the sameas in
`Embodiment | as diagrammedin Fig. 3. Horizontal signal level adjustment means 10
`change the video signal level, in correspondence with the gradient gain, in the horizontal
`direction of the screen. Gate width adjustment means8 change the gate width, in
`correspondence with the gradient gain, in the vertical direction of the screen. A gate width
`correspondence controller 9, in correspondence with the output from the gate width
`adjustment means 8, performs control to change the width of the scanning line output (gate
`signal output) from the scanning-side drive means2.
`[0031] In Fig. 6 is diagrammedthe internal configuration of the horizontal signal level
`adjustment means 10. In Fig. 6, a horizontal gradient processor 66 outputs control values to
`change the video signal level in the horizontal direction in correspondence with the gradient
`gain. For the center position where processing is performed, a prescribed positionis set. A
`horizontal arithmetic processor 65 subjects the video signal to level conversion in
`correspondence with the output from the horizontal gradient processor 66. The output from
`the horizontal arithmetic processor 65 is sent via an output unit to the signal-side drive
`means.
`[0032] In Fig. 7 is given a gain processing state diagram for the horizontal signallevel
`adjustment means 10. In Fig. 7, 100% means that the video signal level is displayed asis,
`while 90% meansthat the video signal is displayed with the level thereof lowered to 90%.
`In Fig. 7, the center of the screen is made the center of gradient gain processing. As may be
`seen in Fig. 7, the signal level is lowered from the center toward the left and right. When
`the APL is high, the gain difference between the center and the left and right peripheries
`becomeslarge, whereas, when the APLis low, that gain difference becomes small. In Fig.
`7, furthermore, an example of parabolic change is diagrammed, but that change may be
`linear. One example of gain values is indicated in Fig. 7, moreover, and those values are
`changed depending on the system.
`[0033] In Fig. 8 is given a gate width processing state diagramfor the gate width
`adjustment means 8. In Fig. 8, 100%indicates a gate width for accumulating the display
`unit signal line potential at 100% of pixel capacity, while 90% meansthat the accumulation
`level is lowered to the 90% level. The accumulation level is lowered by shortening the gate
`width, which produces equivalent results as lowering the signal level. In Fig. 8, the screen
`center is made the center of gate width processing. As diagrammedin Fig. 8, the measure
`of the gate width (accumulation level) is brought down from the center in the up and down
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`TOKKAT 2002-116728
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`directions. When the APLis high, the difference between the center and the upper and
`lower peripheries becomes large, whereas when the APL is low,that difference becomes
`small. In Fig. 8, moreover, an example of a parabolic change is diagrammed, butthat
`change maybelinear. One example of gate width valuesis indicated in Fig. 8, moreover,
`and those values can change depending on the system.
`[0034] In Fig. 9 is given a timing waveformdiagramfor the gate signal output. As
`diagrammed in Figs. 7 and 8, if processing is performed for applying gradient gain changes
`in both the