JP2002149109A - Display device and driving method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost display device and driving method capable of preventing a driving means from being broken down due to temperature rise without the need of installing a temperature detection means. SOLUTION: A temperature estimate based on the temperature of a data driving circuit 6 is attained by using a picture signal VD inputted by a temperature estimate unit; a picture signal controller 1 transforms the picture signal VD into a picture signal VF for controlling the temperature rise of the data driving circuit 6; and a sub-field processor 3, scanning/sustaining drive circuit 5, and the data driving circuit 6 drive discharge cells of a plasma display panel 7 by using the transformed picture signal VF.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a display device for displaying an image in accordance with an input image signal and a driving method thereof.

[0002]

2. Description of the Related Art PDP (Plasma Display Panel)
Is advantageous in that it can be made thinner and have a larger screen. In this plasma display device, an image is displayed by utilizing light emission at the time of discharge of a discharge cell constituting a pixel.
In order to cause the discharge cells to emit light, a drive circuit that applies a high-voltage drive pulse to each electrode constituting the discharge cells is used.

For this reason, in the conventional plasma display device, the power consumption of the drive circuit is large. In particular, the power consumption of the data drive circuit that drives the address electrodes is the largest. The power consumption of the data drive circuit changes depending on the displayed image. In particular, when displaying an image having a checkerboard pattern for each of R, G, and B pixels, the number of changes in the drive pulse voltage increases, and As the charge / discharge voltage power to the power supply increases, the power consumption increases, the allowable loss of the data driver LSI (large-scale integrated circuit) constituting the data drive circuit greatly exceeds, and the data driver LSI may be destroyed. .

In order to prevent the destruction of the data drive circuit, Japanese Patent Application Laid-Open No. H11-38930 discloses that a temperature sensor is provided in an address driver circuit (data drive circuit).
A display device is disclosed in which the temperature sensor detects a temperature rise of an address driver circuit and suppresses the temperature rise based on the detected temperature.

[0005]

However, an image in which the temperature of the data drive circuit is likely to rise, such as an image having a checkered pattern for each of the R, G, and B pixels, is included in a normal natural image. For such a special image, a temperature sensor serving as a temperature detecting means is provided in the data driver LSI, or if a data driver LSI having a large allowable loss is used, the data driver The cost of the LSI increases, and thus the cost of the display device increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a display device and a driving method thereof that can prevent the destruction of the driving means due to temperature rise at low cost without providing a temperature detecting means.

[0007]

Means for Solving the Problems (1) First Invention A display device according to a first invention is a display device for displaying an image in accordance with an input image signal, and is arranged in a matrix. A display unit including a plurality of pixels; a driving unit that drives a selected pixel in the display unit; a temperature estimation unit that estimates a temperature estimation value corresponding to the temperature of the driving unit from an image signal; Image signal converting means for converting the image signal into an image signal for suppressing a rise in temperature of the driving means, wherein the driving means drives a selected pixel in the display unit according to the image signal converted by the image signal converting means. Is what you do.

In the display device according to the present invention, a temperature estimation value corresponding to the temperature of the driving means is estimated from the input image signal, and the image signal increases the temperature of the driving means in accordance with the estimated temperature estimation value. The image signal is converted into the image signal to be suppressed, and the selected pixel in the display unit is driven according to the converted image signal.

As described above, since the temperature estimation value corresponding to the temperature of the driving means is estimated from the image signal, the temperature of the driving means can be obtained without providing the temperature detecting means. Further, since the image signal is converted so as to suppress the temperature rise of the driving means in accordance with the temperature estimation value, it is possible to prevent the driving means from being destroyed due to the temperature rise without using a high cost driving means having a large permissible loss. be able to. As a result, it is possible to prevent the driving means from being destroyed due to a rise in temperature at low cost without providing a temperature detecting means.

(2) Second invention In the display device according to the second invention, in the configuration of the display device according to the first invention, one field is divided into a plurality of subfields and selected for each subfield. A sub-field conversion unit for converting an image signal of one field into a sub-field image signal for each sub-field in order to perform gradation display by driving the pixel; Is for estimating the temperature.

In this case, since the temperature of the driving means is estimated from the sub-field image signal for each sub-field, when performing gradation display, the temperature of the driving means can be accurately determined in accordance with the actual driving state. Can be estimated.

(3) Third invention In a display device according to a third invention, in the configuration of the display device according to the second invention, the display section includes a plurality of address electrodes constituting pixels, and And address electrode driving means for driving the address electrodes.

In this case, the temperature rise of the address electrode driving means for driving the address electrodes can be suppressed, so that the address electrode driving means which consumes particularly large power in the display device can be protected from destruction due to the temperature rise. Thus, the reliability of the display device can be improved.

(4) Fourth Invention In a display device according to a fourth invention, in the configuration of the display device according to the second or third invention, the temperature estimating means comprises a subfield image signal between pixels of the display unit. Are subjected to a logical operation on each of the data, and an estimated temperature value is obtained based on the sum of the operation results.

In this case, since each data of the subfield image signal is logically operated between the pixels of the display unit and the temperature estimation value is obtained based on the sum of the operation results, each of the R, G, and B pixels is obtained. The temperature estimation value can be obtained based on an image having a large power consumption, such as an image having a checkered pattern, and the temperature of the driving unit can be obtained with high accuracy from the image signal.

(5) Fifth Invention In a display device according to a fifth invention, in the configuration of the display device according to the fourth invention, the temperature estimating means integrates the sum of the operation results for each field and integrates the sum. The estimated heat value is obtained by subtracting the heat radiation amount of the driving means from the calculated value.

In this case, the sum of the operation results is integrated for each field, and the estimated value of the temperature is obtained by subtracting the amount of heat radiation of the driving means from the integrated value. The temperature estimation value can be obtained more accurately.

(6) Sixth Invention A display device according to a sixth invention is the display device according to any one of the first to fourth inventions, wherein the display section is divided into a plurality of blocks and the drive is performed. The means includes a plurality of driving means provided for each block, and the temperature estimating means obtains an estimated temperature value for each driving means.

In this case, the display section is divided into a plurality of blocks, and a driving means is provided for each block, and a temperature estimation value is obtained for each driving means. Destruction can be prevented.

(7) Seventh invention In a display device according to a seventh invention, in the configuration of the display device according to the sixth invention, the temperature estimating means includes a plurality of temperature estimation values obtained for each driving means. Is output as the estimated temperature value.

In this case, since the maximum temperature estimation value among the plurality of temperature estimation values is output as the temperature estimation value, the temperature rise of each driving means is suppressed based on the driving means having the highest temperature. Therefore, even when there are a plurality of driving units, all the driving units can be reliably protected from destruction due to a rise in temperature.

(8) Eighth Invention In the display device according to the eighth invention, in the configuration of the display device according to any one of the first to seventh inventions, the image signal converting means converts the image signal into peripheral pixels. By filtering between the image signals, the image signal is converted into an image signal that suppresses a rise in temperature of the driving unit.

In this case, the image signal is converted into an image signal which suppresses a rise in the temperature of the driving means by filtering the image signal between neighboring pixels. Therefore,
Since the image signal is averaged by filtering between peripheral pixels, the number of changes in the voltage of the driving pulse can be reduced, so that the current for charging and discharging the panel can be reduced, and the power consumption can be reduced. This can prevent the driving means from being destroyed due to a rise in temperature.

(9) Ninth Invention In a display device according to a ninth invention, in the configuration of the display device according to the eighth invention, the image signal conversion means increases the filtering effect as the estimated temperature value increases. Things.

In this case, since the filtering effect increases as the estimated temperature value increases, when the temperature of the driving unit increases, the image signal is sufficiently averaged between neighboring pixels to reduce the voltage of the driving pulse. The number of changes can be reduced sufficiently, the current for charging and discharging the panel can be reduced, and the power consumption can be reduced sufficiently to prevent the driving means from being destroyed due to a rise in temperature.

(10) Tenth invention A display device according to a tenth invention is the display device according to any one of the first to ninth inventions, wherein the image signal conversion means is provided between adjacent pixels of the image signal. When the difference is equal to or greater than a preset reference value, the image signal is filtered between neighboring pixels to convert the image signal into an image signal that suppresses a rise in temperature of the driving unit.

In this case, when the difference between the adjacent pixels of the image signal is equal to or larger than a predetermined reference value, the image signal is filtered between the peripheral pixels, thereby suppressing the temperature rise of the driving means. Therefore, the filtering can be performed only on a portion where the difference between the image signals between the adjacent pixels is large, that is, a portion where the image changes greatly. Therefore, it is possible to sufficiently suppress the temperature rise of the driving unit for an image having a large change between adjacent pixels such as a checkered pattern, and to prevent deterioration of the image quality for a normal image with a small change. .

(11) Eleventh invention A display device according to an eleventh invention is the display device according to any one of the second to fifth inventions, wherein the image signal conversion means comprises: By making at least a part of the plurality of bits identical to the surrounding pixels,
The image signal is converted into an image signal that suppresses a temperature rise of the driving unit.

In this case, the image signal is converted into an image signal which suppresses a temperature rise of the driving means by making at least a part of a plurality of bits of the sub-field image signal identical to peripheral pixels. Therefore, when the temperature estimation value is equal to or higher than the reference value and there is a possibility that the driving unit is destroyed, at least a part of the plurality of bits of the image signal is made the same as the surrounding pixels to reduce the number of times the voltage of the driving pulse changes. Accordingly, the current for charging and discharging the panel can be reduced, the power consumption can be reduced, and destruction due to a rise in temperature of the driving means can be prevented.

(12) Twelfth Invention In the display device according to the twelfth invention, in the configuration of the display device according to the eleventh invention, the image signal conversion means may include a subfield image of a pixel having a large value between peripheral pixels. The lower bits of the signal are replaced with the lower bits of a subfield image signal of a pixel having a small value.

In this case, lower bits of a subfield image signal of a pixel having a larger value are replaced with lower bits of a subfield image signal of a pixel having a smaller value between neighboring pixels. Therefore, by changing the lower bits of the bright pixel without changing the signal of the dark pixel, a part of the subfield image signal can be made the same. Therefore, it is possible to reduce the number of changes in the voltage of the driving pulse while preventing the image quality from being deteriorated in dark pixels which have a large effect when the subfield image signal is made the same, thereby reducing the current for charging and discharging the panel. Power consumption can be reduced, and destruction of the driving means due to a rise in temperature can be prevented.

(13) Thirteenth Invention In the display device according to the thirteenth invention, in the configuration of the display device according to the eleventh invention, the image signal conversion means includes a subfield image of a pixel having a large value between peripheral pixels. The lower bits of the signal are replaced with the lower bits of the sub-field image signal of the pixel having the smaller value, and a value corresponding to the difference between the replaced value of the pixel having the larger value and the original value is added to peripheral pixels. is there.

In this case, the lower bits of the sub-field image signal of the pixel having the larger value between the peripheral pixels are replaced with the lower bits of the sub-field image signal of the pixel having the smaller value. A value corresponding to the difference between the original values is added to peripheral pixels. Therefore, a difference caused by equalizing a part of the subfield image signal can be added to peripheral pixels. Therefore, the deterioration of the image quality in the bright pixels caused when the sub-field image signals are identified can be compensated for by the peripheral pixels, and the number of changes in the voltage of the driving pulse can be reduced without deteriorating the image. In addition, the current for charging and discharging the panel can be reduced, the power consumption can be reduced, and destruction of the driving means due to a rise in temperature can be prevented.

(14) Fourteenth Invention In a display device according to a fourteenth invention, in the configuration of the display device according to the second to seventh inventions, the image signal conversion means may be configured such that the larger the estimated temperature value is, the more the same is obtained. The number of bits to be converted is increased.

In this case, the larger the estimated temperature value, the larger the number of bits to be made identical. Therefore, when the temperature of the driving means becomes high, the subfield image signal becomes sufficiently identical between neighboring pixels, and The number of pulse voltage changes can be reduced sufficiently, and the current required to charge and discharge the panel can be reduced.Power consumption can be reduced sufficiently to prevent destruction of the driving means due to temperature rise. Can be.

(15) Fifteenth Invention A display device driving method according to a fifteenth invention is directed to a display unit including a plurality of pixels arranged in a matrix, and a driving unit for driving a selected pixel in the display unit. A method for driving a display device that displays an image in accordance with an input image signal, comprising: estimating a temperature estimation value corresponding to the temperature of the driving unit from the image signal; The method includes a step of converting the image signal into an image signal that suppresses a rise in temperature of the driving unit, and a step of driving a selected pixel in the display unit by the driving unit according to the converted image signal.

In the display device driving method according to the present invention, a temperature estimation value corresponding to the temperature of the driving means is estimated from the input image signal, and the image signal is converted to the driving means according to the estimated temperature estimation value. The image signal is converted into an image signal that suppresses a temperature rise, and a selected pixel in the display unit is driven according to the converted image signal.

As described above, since the temperature estimation value corresponding to the temperature of the driving means is estimated from the image signal, the temperature of the driving means can be obtained without providing the temperature detecting means. Further, since the image signal is converted so as to suppress the temperature rise of the driving means in accordance with the temperature estimation value, it is possible to prevent the driving means from being destroyed due to the temperature rise without using a high cost driving means having a large permissible loss. be able to. As a result, it is possible to prevent the driving means from being destroyed due to a rise in temperature at low cost without providing a temperature detecting means.

(16) Sixteenth Invention A driving method for a display device according to a sixteenth invention is directed to a method for driving a display device according to the fifteenth invention, wherein one field is divided into a plurality of subfields and the subfield is divided into a plurality of subfields. Converting the image signal of one field into a subfield image signal of each subfield in order to drive a pixel selected for each field to perform gradation display; And estimating the temperature of the driving means from the above.

In this case, since the temperature of the driving means is estimated from the sub-field image signal for each sub-field, when performing gradation display, the temperature of the driving means can be accurately determined according to the actual driving state. Can be estimated.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an AC type plasma display device will be described as an example of a display device according to the present invention. Note that a display device to which the present invention is applied is not particularly limited to an AC plasma display device, and a temperature of a driving unit that drives a pixel by displaying an image according to an input image signal changes. If there is, it can be similarly applied to other display devices.

First, a plasma display device according to a first embodiment of the present invention will be described. FIG. 1 is a block diagram showing the configuration of the plasma display device according to the first embodiment of the present invention.

The plasma display device shown in FIG.
It comprises an image signal controller 1, an image-subfield associator 2, a subfield processor 3, a temperature estimator 4, a scan / sustain drive circuit 5, a data drive circuit 6, and a plasma display panel 7.

The image signal controller 1 receives an image signal VD including a vertical synchronizing signal and a horizontal synchronizing signal. The image signal controller 1 outputs an image signal VF obtained by filtering the input image signal VD according to the temperature estimation value TE output from the temperature estimator 4 to the image-subfield association device 2.

The image-subfield associator 2 is 1
Since the field is divided into a plurality of subfields and displayed, the subfield image data SB which is image data for each subfield is obtained from the image signal VF of one field.
And a subfield processor 3 and a temperature estimator 4
Output to

The subfield processor 3 outputs a data driver drive control signal from the subfield image data SB and the like.
A scan driver drive control signal and a sustain driver drive control signal are created, a data driver drive control signal is output to the data drive circuit 6, and a scan driver drive control signal and a sustain driver drive control signal are output to the scan / sustain drive circuit 5. I do.

The temperature estimator 4 calculates a temperature estimated value TE corresponding to the temperature of the data drive circuit 6 using the subfield image data SB, and outputs the temperature estimated value TE to the image signal controller 1.

The plasma display panel 7 includes a plurality of address electrodes (data electrodes), a plurality of scan electrodes (scan electrodes), and a plurality of sustain electrodes (sustain electrodes). The plurality of address electrodes are arranged in the vertical direction of the screen, and the plurality of scan electrodes and the plurality of sustain electrodes are arranged in the horizontal direction of the screen. The plurality of sustain electrodes are commonly connected. Address electrode,
A discharge cell is formed at each intersection of the scan electrode and the sustain electrode, and each discharge cell forms a pixel on the screen.

The data drive circuit 6 is connected to a plurality of address electrodes of the plasma display panel 7. The scan / sustain drive circuit 5 includes a plasma display panel 7
Are connected to a plurality of scan electrodes and sustain electrodes.

In accordance with the data driver drive control signal, the data drive circuit 6 applies an initialization pulse for adjusting wall charges to the address electrodes during the initialization period. The scan / sustain drive circuit 5 applies an initialization pulse for adjusting wall charges to the scan electrode and the sustain electrode during the initialization period according to the scan driver drive control signal and the sustain driver drive control signal. Thereby, the wall charges of each electrode are adjusted to wall charges suitable for the subsequent address discharge and sustain discharge.

The data drive circuit 6 applies a write pulse to a corresponding address electrode of the plasma display panel 7 according to image data in a write period according to a data driver drive control signal. The scan / sustain drive circuit 5 sequentially applies the write pulse to the plurality of scan electrodes while shifting the shift pulse in the vertical scanning direction in the write period according to the scan driver drive control signal. Thereby, an address discharge is performed in the corresponding discharge cell.

The scan / sustain drive circuit 5 applies a periodic sustain pulse to a plurality of scan electrodes of the plasma display panel 7 during a sustain period in accordance with a scan driver drive control signal, and a plurality of sustain pulses in accordance with a sustain driver drive control signal. Are simultaneously applied to the sustain electrodes having a phase shift of 180 degrees with respect to the sustain pulses of the scan electrodes. As a result, a sustain discharge is performed in the corresponding discharge cell, and each pixel emits light or no light for each subfield.

As described above, in the plasma display device shown in FIG.
(Address Display-Period Separation) method is used. In the ADS method, one field is temporally divided into a plurality of subfields, and each subfield is divided into an initialization period, a writing period, a sustain period, and the like, and setup processing of each subfield is performed in the initialization period. In addition, an address discharge for selecting a discharge cell to be turned on in a writing period is performed, and a sustain discharge for display is performed in a sustain period.

FIG. 2 is a block diagram showing a configuration of the temperature estimator 4 shown in FIG. The temperature estimator 4 shown in FIG. 2 includes a peripheral pixel operation circuit 41, an addition circuit 42, and a temperature estimation circuit 43.

The peripheral pixel calculation circuit 41 calculates the exclusive OR of the subfield image data SB between adjacent pixels in each subfield, and outputs the calculation result for each subfield to the addition circuit 42. Adder circuit 42
, Sequentially adds the input operation results of the subfields, and outputs the sum of the operation results for one field to the temperature estimation circuit 43 as an addition value SD. The temperature estimation circuit 43
A temperature estimation value TE is output by integrating the addition value SD and subtracting the heat radiation amount.

FIG. 3 shows the operation circuit 4 between the peripheral pixels shown in FIG.
FIG. 4 is a schematic diagram for explaining arithmetic processing by 1 and an adding circuit; In the example shown in FIG. 3, the plasma display panel 7 is simplified for ease of explanation, and six address electrodes R1, G1, B1, R are used as address electrodes.
2, G2, and B2 are arranged, and four lines 1 to 4 are arranged as scan electrodes and sustain electrodes, and a discharge cell SE is formed at each intersection. Further, “○” in each discharge cell SE indicates that the value of the subfield image data SB of the discharge cell is 1, and that the discharge cell is lit, and “×” indicates This indicates that the value of the subfield image data SB of the discharge cell is 0 and that the discharge cell is not lit.

When the lighting / non-lighting state of each discharge cell is determined by the subfield image data SB as shown in FIG. 3, the peripheral pixel operation circuit 41 firstly performs exclusive control of the data between the left and right pixels. OR operation is performed sequentially. For example, the exclusive OR of the data of the discharge cell formed by the line 1 and the address electrode R1 and the data of the discharge cell on the right formed by the line 1 and the address electrode G1 is 1
In the same manner, exclusive OR of the data between the left and right pixels is sequentially calculated. In line 1, 1,1,1,1,1 is calculated, and the total of the calculation results between the left and right pixels is 5. Similarly, the sum of the calculation results between the left and right pixels on lines 2 to 4 is 2, 3, and 2.

The peripheral pixel operation circuit 41 calculates the exclusive OR of the data between the upper and lower pixels in the same manner as described above. For example, the data of the discharge cell formed by the line 1 and the address electrode R1 and the line The exclusive OR of the data of the discharge cells formed by the address 2 and the address electrode R1 becomes 0. Similarly, the exclusive OR of the data between the upper and lower pixels is sequentially calculated in the same manner. 0, 1, 1, 0, 0, 1 are calculated between pixels, and the total of the calculation results between the upper and lower pixels is 3. Similarly, the sum of the calculation results between the upper and lower pixels on line 2 and line 3 is 4, and
The total of the calculation results between the upper and lower pixels of each pixel on line 3 and each pixel on line 4 is 3.

As described above, the peripheral pixel operation circuit 4
3, the exclusive OR of the data between the left and right and upper and lower pixels is calculated from the subfield image data SB.
In the example shown in (1), the sum of exclusive OR with peripheral pixels is 22
Becomes

FIG. 4 is a diagram showing an example of a calculation result in a writing period of each subfield in the ADS method. In the example shown in FIG. 4, one field is divided into four subfields SF1 to SF4,
In the case where the display image of No. 1 is an image having the display pattern shown in FIG. 3, the total of the calculation results with respect to the write pulse of the write period of the subfield SF1 is 22, and thereafter, similarly, the write pulse of the write period of each of the subfields SF2 to SF4. Is, for example, 15, 1
0,5. These operation results are sequentially added by the addition circuit 42. In the example shown in FIG. 4, the total value of the operation results during one field period is 52, and this value is the added value SD.
Is output to the temperature estimation circuit 43.

As described above, the peripheral pixel operation circuit 41 sequentially calculates the exclusive OR of the data between the adjacent pixels of the write pulse applied by the data drive circuit 6 during the write period, and the adder circuit 42 operates for one field. By adding the calculation results of the minutes, it is possible to obtain data for calculating the temperature estimation value corresponding to the temperature rise of the data drive circuit 6.

The exclusive OR operation between the peripheral pixels by the peripheral pixel operation circuit 41 is not particularly limited to the operation between the left and right pixels and the upper and lower pixels as described above. Alternatively, only the exclusive OR between the upper and lower pixels may be calculated without calculating the logical OR.

That is, the temperature estimation value estimated by the temperature estimator 4 is a value corresponding to the temperature of the data driving circuit 6, and the data driving circuit 6 uses the address electrodes arranged in the vertical direction of the plasma display panel 7. Since the driving circuit is used for driving, if a change in the driving voltage can be detected for each address electrode, the temperature rise of the data driving circuit can be substantially estimated.

Therefore, in order to simplify the arithmetic processing,
As shown in FIG. 5, only the exclusive OR between the upper and lower pixels may be performed, and the data may be processed in the same manner as described above to obtain the temperature estimation value. In the example shown in FIG. 5, the sum of the operation results between line 1 and line 2 is 3, and line 2
The sum of the calculation results of the line 3 and the line 3 is 4, the sum of the calculation results of the lines 3 and 4 is 3, and the total value of these is 10.

In this case, the operation result in each subfield is, for example, as shown in FIG.
Is 10 and the subfields SF2 to SF2
The calculation result of 4 becomes 7, 5, 3, and the total of the calculation results in one field period becomes 25.

FIG. 7 is a block diagram showing a configuration of temperature estimating circuit 43 shown in FIG. Temperature estimation circuit 4 shown in FIG.
3 is an adder 44, a memory 45, and a heat radiation amount calculation circuit 4.
6 inclusive.

The adder 44 includes an added value SD for one field added by the adding circuit 42 and a heat radiation amount calculating circuit 46.
And outputs the result to the memory 45. Memory 45
Stores the output of the adder 44 for each field, outputs the stored value as the temperature estimation value TE, and outputs the value to the heat radiation amount calculation circuit 46. Heat radiation calculation circuit 4
6 is (1) in the temperature estimation value TE output from the memory 45.
−α), and outputs a value obtained by subtracting the heat radiation from the estimated temperature value TE to the adder 44. Here, α is a predetermined coefficient that corresponds to the heat radiation and satisfies 0 <α <1.

By the above processing, the value obtained by subtracting the heat radiation from the temperature estimation value TE for each field is added to the addition circuit 42.
Is added to the added value SD corresponding to the temperature rise in one field output from, and the added result is output as the estimated temperature value TE.

FIG. 8 is a block diagram showing a configuration of the image signal controller 1 shown in FIG. The image signal controller 1 shown in FIG. 8 includes delay units 11 to 13, a subtractor 14, and multipliers 15 to 1.
7, an adder 18, a selector 19, comparators 20, 21 and a decision circuit 22.

Each of the delay units 11 to 13 is a one-pixel delay unit. The image signal VD is delayed by one pixel, and an output delayed by one pixel is output to the subtractor 14 and the multiplier 15.
The output delayed by two pixels is output to the subtractor 14, the multiplier 16, and the selector 19, and the output delayed by three pixels is output to the multiplier 17.

The multiplier 15 outputs (1−1) to the output of the delay unit 11.
a) / 2 is multiplied, and the multiplication result is output to the adder 18.
The multiplier 16 multiplies the output of the delay unit 12 by a, and outputs the result of the multiplication to the adder 18. The multiplier 17 includes the delay unit 13
Is multiplied by (1-a) / 2, and the multiplication result is added to the adder 1
8 is output.

The multipliers 15 to 17 receive the estimated temperature value TE. The multipliers 15 to 17 decrease the coefficient a (1/2 ≦ a ≦ 1) as the estimated temperature value TE increases. Set to a value. The adder 18 adds the outputs of the multipliers 15 to 17 and outputs the addition result to the selector 19.

The above-described delay units 11 to 13 and multipliers 15 to 1
7 and the adder 18 constitute a low-pass filter in the horizontal direction of the display screen. As the temperature estimation value TE increases, the band of the low-pass filter becomes narrower, data between adjacent pixels is averaged, and the An image signal with little change is output to the selector 19.

The comparator 20 compares the estimated temperature value TE with a preset first reference value Vset1, and calculates the estimated temperature value T
When E is greater than or equal to the first reference value Vset1, a high-level comparison result signal is output to the determination circuit 22; otherwise, a low-level comparison result signal is output to the determination circuit 22.

The subtracter 14 calculates the difference between the output of the delay unit 11 and the output of the delay unit 12, and outputs the result of the subtraction to the comparator 21.

The comparator 21 compares the output of the subtractor 14 with a second reference value Vset2 set in advance.
Is higher than the second reference value Vset2, a high-level comparison result signal is output to the determination circuit 22; otherwise, a low-level comparison result signal is output to the determination circuit 22. Therefore, the output of the subtractor 14 is equal to the second reference value Vse
In the case of t1 or more, that is, when the change of the image signal between adjacent pixels is large, the comparator 21 outputs a high-level comparison result signal to the determination circuit 22 as a comparison result signal.

The decision circuit 22 selects the output of the adder 18 for the selector 19 when the comparison result signals of the comparators 20 and 21 are both at the high level, and otherwise selects the delay unit 12
To select the output of The selector 19 outputs the output of the adder 18, that is, the image signal averaged by the low-pass filter, as the image signal VF only when the image change is large and the temperature estimation value TE is high, and is filtered in other cases. No image signal VD
As the image signal VF.

As described above, in the image signal controller 1, when the change in the image is large and the estimated temperature value TE is high, the image signal is converted into the image signal in which the change in the signal level between pixels is reduced by the low-pass filter. The power consumption of the data drive circuit 6 can be reduced, and in the case of a normal image, since the image is output as it is, deterioration of the image quality can be prevented.

In the above example, one-pixel delay units are used as the delay units 11 to 13, but 1H (one horizontal scanning period)
A low-pass filter in the vertical direction of the display screen may be configured by using a delay device to reduce a change in signal level between pixels in the vertical direction. Further, both the one-pixel delay device and the 1H delay device may be used. In combination, a signal change between pixels may be reduced by using a low-pass filter in the horizontal direction and the vertical direction.

The output of the adder 18 is selected when both comparison result signals of the comparators 20 and 21 are at a high level, that is, when the image change is large and the temperature estimation value TE is large. The output of the adder 18 may be selected when the comparison result signal of either the comparator 20 or the comparator 21 is at a high level, that is, when the change in the image is large or when the estimated temperature TE is large.

In the present embodiment, the plasma display panel 7 corresponds to a display unit, the data driving circuit 6 corresponds to a driving unit, the temperature estimator 4 corresponds to a temperature estimating unit, and the image signal controller 1 controls an image. It corresponds to signal conversion means.
Further, the image-subfield associator 2 corresponds to a subfield converter, and the data drive circuit 6 corresponds to an address electrode driver.

Next, the effect when the image signal VD is filtered and converted into the image signal VF as described above will be described. FIG. 9 is a diagram illustrating an example of an image displayed on the plasma display panel.

In FIG. 9, the numerical value shown in each discharge cell SE indicates the luminance. In the example shown in FIG. 9, a checkerboard pattern in which the luminance is 15 or 0 for each set of R, G, and B pixels is shown, and the average luminance of this screen is 7.5. .

In this case, for example, as shown in FIG.
If one subfield is composed of one subfield and the weight of each subfield is 1, 2, 4, and 8, the write pattern in each subfield is the write pattern shown in FIG. That is, the write pattern in all subfields is a checkerboard pattern, the write pattern of each address electrode R1, G1, B1, R2, G2, B2 is alternately repeated as 0 and 1, and the subfield image between adjacent pixels is repeated. The change in data is greatest. Therefore, when the write pattern shown in FIG. 10 is used as it is, the charge / discharge power to the panel increases, so that the power consumption increases and the temperature of the data drive circuit 6 rises.

On the other hand, in the present embodiment, when the image signal VD for displaying the image shown in FIG. 9 is input to the image signal controller 1, it is converted into the image signal VF for displaying the image shown in FIG. That is, the luminance is averaged between the adjacent pixels by the image signal controller 1, for example, the luminance of all the pixels becomes 7, and the average luminance of the screen becomes 7.

In this case, subfields SF1 to SF3
Is the pattern shown in FIG. 12, and the write pattern of the subfield SF4 is the write pattern shown in FIG. That is, the subfield S
In F1 to SF3, all the discharge cells are turned on and the number of voltage changes of the write pulse is reduced. In the subfield SF4, all the discharge cells are turned off and the number of voltage changes of the write pulse is reduced. Therefore, the number of voltage changes of the write pulse is reduced in all subfields, so that the charge / discharge power to the panel is reduced, the power consumption of the data drive circuit 6 is reduced, and the temperature rise of the data drive circuit 6 is suppressed. be able to.

As described above, in this embodiment, the temperature estimation value TE corresponding to the temperature of the data drive circuit 6 is obtained from the image signal.
, So without installing a temperature sensor,
Since the temperature of the data drive circuit 6 can be obtained, and the image signal is filtered to average the luminance of the image signal according to the temperature estimation value TE and the change of the image signal between adjacent pixels, the allowable loss The destruction of the data drive circuit 6 due to a rise in temperature can be prevented without using a large and expensive data driver LSI.

Next, a plasma display device according to a second embodiment of the present invention will be described. FIG.
FIG. 6 is a block diagram illustrating a configuration of a plasma display device according to a second embodiment of the present invention.

The difference between the plasma display device shown in FIG. 14 and the plasma display device shown in FIG.
The image signal controller 1 and the temperature estimator 4 are changed to the image signal controller 1a and the temperature estimator 4a, and the other points are the same as those of the plasma display device shown in FIG. The same reference numerals are given, and only different points will be described in detail below.

The temperature estimator 4a divides the plasma display panel 7 into a plurality of blocks for each data driver LSI constituting the data drive circuit 6, and calculates a temperature estimation value TEn calculated for each block, that is, for each data driver LSI, as an image signal. Output to the controller 1a.

The image signal controller 1a performs a filtering process on the image signal VD according to the temperature estimation value TEn for each block, and converts the image signal VF for suppressing the temperature rise of the data driver LSI for each block into an image-subfield. Output to associator 2.

In this embodiment, the temperature estimator 4a corresponds to the temperature estimating means, the image signal controller 1a corresponds to the image signal converting means, and the other points are the same as in the first embodiment.

FIG. 15 is a block diagram showing a configuration of temperature estimator 4a shown in FIG. The temperature estimator 4a shown in FIG. 15 includes a block division circuit 40, four peripheral pixel operation circuits 41a to 41d, four addition circuits 42a to 42d, and four temperature estimation circuits 43a to 43d.

In the present embodiment, there are four data driver LSIs constituting the data driving circuit 6, and the plasma display panel 7 is divided into four, with the area including the address electrodes driven by each data driver LSI as one block. Then, the temperature estimator 4a calculates the temperature corresponding to the temperatures of the data driver LSIs of the four blocks as follows.
Two temperature estimation values TE1 to TE4 are calculated. In the above example, the number of divisions is not particularly limited to this example, and various division numbers can be used.

The block dividing circuit 40 divides the input subfield image data SB into blocks and outputs the divided data to peripheral pixel operation circuits 41a to 41d provided for the corresponding blocks.

Peripheral pixel operation circuit 41a, addition circuit 42
a and the temperature estimating circuit 43a are circuits provided for the first block of the four divided blocks, and are similar to the peripheral pixel operation circuit 41, the adding circuit 42, and the temperature estimating circuit 43 shown in FIG. It operates to calculate the temperature estimation value TE1 of the first block and outputs it to the image signal controller 1a.

Thereafter, similarly, the peripheral pixel operation circuit 41b,
The temperature estimation value TE2 of the second block is calculated by the addition circuit 42b and the temperature estimation circuit 43b, and the calculation circuit 41c between the peripheral pixels, the addition circuit 42c, and the temperature estimation circuit 43c
, The temperature estimation value TE3 of the third block is calculated, the temperature estimation value TE4 of the fourth block is calculated by the peripheral pixel calculation circuit 41d, the addition circuit 42d, and the temperature estimation circuit 43d, and are output to the image signal controller 1a. You.

The image signal controller 1a provides a temperature estimation value TE1 for each block in the same manner as the image signal controller 1 shown in FIG.
Filtering is performed in accordance with .about.TE4, and when the temperature estimation value is high and the image change is large, the image signal VD is converted into an image signal VF in which data between adjacent pixels is averaged for each block and output. I do.

As described above, in the present embodiment, the image signal is converted according to the temperature estimation value for each data driver LSI constituting the data drive circuit 6, and the temperature rise of each data driver LSI is suppressed, and The driver LSIs can be individually protected from destruction due to temperature rise.

The temperature rise of the data drive circuit 6 when the plasma display panel 7 is divided for each data driver LSI constituting the data drive circuit 6 and an estimated temperature value corresponding to the temperature of each data driver LSI is calculated. The method of suppressing is not particularly limited to the above example, and various changes are possible. For example, as described below, a temperature estimation value of each block may be obtained, a maximum value may be detected from the obtained temperature estimation values, and an image signal may be converted based on the detected maximum value.

FIG. 16 is a block diagram showing the configuration of another example of the temperature estimator. The difference between the temperature estimator 4b shown in FIG. 16 and the temperature estimator 4a shown in FIG. 15 is that a maximum value detection circuit 47 is added, and the other points are the same as those of the temperature estimator 4a shown in FIG. Therefore, the same portions are denoted by the same reference numerals, and only different portions will be described in detail below.

As shown in FIG. 16, the maximum value detection circuit 47
Receives the temperature estimation value of each block output from the temperature estimation circuits 43a to 43d, detects the maximum value from the four temperature estimation values, and outputs the detected maximum value as the temperature estimation value TE.

Therefore, the temperature estimator 4b shown in FIG.
Is used in the plasma display device shown in FIG. 1, the temperature rise of each data driver LSI can be suppressed based on the data driver LSI having the highest temperature. Even when there are a plurality of data driver LSIs, The data driver LSI can be reliably protected from destruction due to temperature rise.

Next, a plasma display device according to a third embodiment of the present invention will be described. FIG.
FIG. 9 is a block diagram illustrating a configuration of a plasma display device according to a third embodiment of the present invention.

The difference between the plasma display device shown in FIG. 17 and the plasma display device shown in FIG.
The image signal controller 1 is changed to the image signal controller 1b, the connection between the image-subfield associator 2, the image signal controller 1b, and the temperature estimator 4 is changed. Are the same as those of the plasma display device shown in FIG. 1, the same portions are denoted by the same reference numerals, and only different points will be described in detail below.

In the image-subfield associator 2,
An image signal VD including a vertical synchronization signal and a horizontal synchronization signal is input. The image-subfield correlator 2 is 1
Subfield image data SB, which is image data for each subfield, is created from the field image signal VD and output to the image signal controller 1b and the temperature estimator 4.

The image signal controller 1b makes the input subfield image data SB equalize a part of a plurality of bits of the subfield image signal with peripheral pixels in accordance with the temperature estimation value TE output from the temperature estimator 4. The subfield image data SBC is output to the subfield processor 3.

The temperature estimator 4 calculates a temperature estimated value TE corresponding to the temperature of the data driving circuit 6 using the subfield image data SB, and outputs the temperature estimated value TE to the image signal controller 1b.

In the present embodiment, the image signal controller 1
b corresponds to the image signal conversion means, and the other points are the same as in the first embodiment.

FIG. 18 shows the image signal controller 1 shown in FIG.
It is a block diagram which shows the structure of b. An image signal controller 1b shown in FIG. 18 includes an adder 11b, delayers 12b and 13
b, comparators 14b and 16b, lower bit replacement unit 15b,
And a selector 17b.

The adder 11b provides the data ER representing the difference between the subfield image data SB and the value of the lower bit output from the lower bit replacer 15b in which the lower bit is replaced and the original value.
And outputs the addition result to the delay unit 12b. The delay units 12b and 13b are 1H (one horizontal scanning period) delay units, delay image data by 1H, and output an output delayed by 1H to the comparator 14b and the lower bit replacement unit 15b.

The comparator 14b compares the output of the delay unit 12b with the output of the delay unit 13b, and outputs the result of the comparison to the lower bit replacement unit 15b. The lower-order bit permutator 15b outputs the lower-order subfield data having a larger value among the outputs of the 1H delayer 12b and the 1H delayer 13b according to the comparison result of the comparator 14b and the value of the temperature estimation value TE. The subfield data is replaced with the smaller lower subfield data, and the replaced subfield image data is output to the selector 17b.

The lower bit replacement unit 15b calculates the temperature estimation value T
As the value of E increases, the number of bits of the subfield data to be replaced is increased, the number of bits of adjacent image data to be equalized is increased, and the subfield image data with little change between pixels is output to the selector 17b. .

The comparator 16b compares the estimated temperature value TE with a third reference value Vset3 set in advance. If the estimated temperature value TE is equal to or greater than the third reference value Vset, the lower bit is replaced by the selector 17b. The output of the delay unit 13b is selected, and in other cases, the output of the delay unit 13b is selected.

The selector 17b outputs the output of the delay unit 13b and the lower bit replacement unit 1 according to the instruction of the comparator 16b.
5b, and outputs the subfield image data SBC.

As described above, in the image signal controller 1b, when the temperature estimation value TE is high, a part of the plurality of bits of the sub-field image signal is converted into the sub-field image data which is made the same as the peripheral pixels. , The power consumption of the data drive circuit 6 is reduced, and in the case of a normal image,
Since the image is output as it is, deterioration of the image quality can be prevented.

In the above example, the delay units 12b and 13
As b, a part of a plurality of bits of the subfield image signal is made identical between the peripheral pixels in the vertical direction using a 1H delay device. However, the peripheral pixels in the horizontal direction are made identical between the peripheral pixels in the horizontal direction using a 1-pixel delay device. A part of a plurality of bits may be made the same, and a combination of both a 1H delay unit and a one-pixel delay unit may be used to convert some bits of an image between neighboring pixels in the horizontal and vertical directions. The signal change between pixels may be reduced by making them the same.

Next, the effect of the case where a part of a plurality of bits of the subfield image signal is made identical between neighboring pixels as described above will be described. FIG. 19 is a diagram illustrating an example of an image displayed on the plasma display panel.

In FIG. 19, the numerical value shown in each discharge cell SE indicates the luminance. The example shown in FIG. 19 shows a checkerboard pattern in which the brightness of each pixel is 3 or 12 in which each pixel of R, G, and B is a set, and the average brightness of this screen is 7.5. .

In this case, for example, one field is composed of four subfields as in FIG. 4, and when the weight of each subfield is 1, 2, 4, and 8, the writing pattern of subfields SF1 and SF2 is as shown in FIG. , And the write pattern of the subfields SF3 and SF4 is the pattern shown in FIG. That is, although the writing pattern is different between SF1 and SF2 and SF3 and SF4, the writing pattern becomes a checkered pattern,
The write pattern of each of the address electrodes R1, G1, B1, R2, G2, and B2 is alternately repeated as 0 and 1, and the change of the subfield image data between adjacent pixels is the largest. Therefore, when the write patterns shown in FIGS. 20 and 21 are used as they are, the charge / discharge power to the panel increases, so that the power consumption increases and the temperature of the data drive circuit 6 increases.

On the other hand, in this embodiment, at this time, the temperature estimated value TE output from the temperature estimator 4 becomes large,
In the image signal controller 1b, the lower two bits of the subfield image data are replaced in the case of a pixel having a larger value as compared with the lower adjacent pixel, and the difference caused by the replacement is further added to the lower side. . That is, when the subfield image data SB shown in FIG. 19 is input to the image signal controller 1b, it is converted into the subfield image data shown in FIG. The average luminance of this screen is 7.9, which can represent almost the same brightness as the original checkered pattern shown in FIG.

This is due to the following operation of the image signal controller 1b. First, at the pixels of R1, G1, and B1, the data of line 1 (value 3) is compared with the data of line 2 (value 12), and 3 is output as it is because line 1 is smaller. Next, the data of line 2 (value 1
2) is compared with the data in line 3 (value 3) and
Is smaller, the lower 2 bits of line 2 are replaced by the lower 2 bits of line 3, and 15 is output. At this time, in order to correct the difference 3 from the original value 12 of the line 2,
3 is added to line 4. Therefore, the value of line 4 (original value 12) is 9 at 12-3. Next, the data on line 3 (value 3) is compared with the data on line 4 (value 9),
Since line 3 is smaller, 3 is output as it is. Next, the data of line 4 (value 9) is compared with the data of line 5 (value 3). Since line 4 is larger, the lower 2 bits of line 4 are replaced with the lower 2 bits of line 5, and 11 is output. You. Since there is no line to be compared below the line 5, 3 is output as it is.

In the pixels of R2, G2 and B2, the data of line 1 (value 12) is compared with the value of data of line 2 (value 3). The bits are replaced by the lower two bits of line 2 and 15 is output. At this time, the original value 1 of line 1
-3 is added to line 3 to correct the difference 3 from 2. Therefore, the value of line 3 (original value 12) is 9 at 12-3. Next, the data of line 2 (value 3) is
(Value 9), and 3 is output as it is because line 2 is smaller. Next, the data of line 3 (value 9) is compared with the data of line 4 (value 3).
Is replaced by the lower 2 bits of the data and 11 is output. Next, the data of line 4 (value 3) is the data of line 5 (value 12)
And 3 is output as it is because line 4 is smaller. Since there is no line to be compared below the line 5, 12 is output as it is.

In this example, a value for correcting the difference from the original data due to the replacement is added to the lower line by the adder 11b. For this reason, it is possible to accurately correct the brightness error due to the replacement with the surrounding pixels. Further, in this example, the weight of the subfield is a power of 2, so the error of the replaced value is added as it is. However, the weight of the subfield does not have to be a power of 2. Also, the value for correcting the error due to is not necessarily accurate. If the value corresponding to the difference between the replaced value and the original value is corrected with a substantially similar value, it is possible to sufficiently obtain the effect of correcting the brightness error due to the replacement with peripheral pixels.

When the subfield image data shown in FIG. 22 is displayed on the panel, the subfields SF1 and SF2
Becomes the pattern shown in FIG.
The write pattern of the subfield SF3 is the pattern shown in FIG. 24, and the write pattern of the subfield SF4 is the pattern shown in FIG. That is, in the subfields SF1 and SF2, all the discharge cells are turned on and the number of times of the voltage change of the write pulse disappears, and the number of times of the voltage change of the write pulse also becomes smaller in the subfield SF3 as compared with the original checkerboard write pattern. Is running low. Therefore, since the total number of voltage changes in all subfields is reduced, the power for charging / discharging the panel is reduced, the power consumption of the data drive circuit 6 is reduced, and the temperature rise of the data drive circuit 6 is suppressed. be able to.

Further, by controlling the number of bits of the subfield image data SB to be replaced with the temperature estimation value TE, the temperature rise of the data drive circuit 6 can be more finely suppressed. For example, the temperature estimation value T
When E is small, the number of bits to be replaced is set to 0 bits. When the temperature estimation value TE is somewhat large, the number of bits to be replaced is set to 1 bit. When the temperature estimation value TE is further increased, the number of bits to be replaced is set. Is set to 2 bits and the number of bits to be replaced when the temperature estimation value TE becomes extremely large is set to 3 bits, whereby the temperature rise of the data drive circuit 6 can be more finely suppressed.

As described above, in the present embodiment, the temperature estimation value TE corresponding to the temperature of the data drive circuit 6 is obtained from the image signal.
, So without installing a temperature sensor,
Since the temperature of the data drive circuit 6 can be obtained, and a part of the subfield image data is made identical between neighboring pixels according to the temperature estimation value TE, a high-cost data driver LSI having a large allowable loss is used. Thus, it is possible to prevent the data drive circuit 6 from being destroyed due to a rise in temperature.

Further, the present embodiment and the second embodiment may be combined to determine the temperature estimated value TEn for each block.
The number of bits to be replaced may be changed for each block. By doing so, the temperature rise of each data driver LSI among the plurality of data driver LSIs can be suppressed, and the data driver LSIs can be individually protected from destruction due to the temperature rise.

[0129]

According to the present invention, since the temperature estimation value corresponding to the temperature of the driving means is estimated from the image signal, the temperature of the driving means can be obtained without providing the temperature detecting means. Since the image signal is converted so as to suppress the temperature rise of the driving unit according to the temperature estimation value, without using a high-cost driving unit having a large permissible loss,
The destruction of the driving means due to a rise in temperature can be prevented. As a result, it is possible to prevent the driving means from being destroyed due to a rise in temperature at low cost without providing a temperature detecting means.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a plasma display device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a temperature estimator shown in FIG. 1;

FIG. 3 is a schematic diagram for explaining arithmetic processing by a peripheral pixel arithmetic circuit and an adder circuit shown in FIG. 2;

FIG. 4 is a diagram showing an example of a calculation result in a writing period of each subfield in the ADS method.

FIG. 5 is a schematic diagram for explaining another arithmetic processing by the peripheral pixel arithmetic circuit and the adder circuit shown in FIG. 2;

FIG. 6 is a diagram showing another example of the calculation result in the writing period of each subfield in the ADS method.

FIG. 7 is a block diagram showing a configuration of a temperature estimating circuit shown in FIG. 2;

8 is a block diagram showing a configuration of the image signal controller shown in FIG.

FIG. 9 is a view showing an example of an image displayed on the plasma display panel.

FIG. 10 is a diagram showing a write pattern in each subfield for displaying the image shown in FIG. 9;

FIG. 11 is a view showing an example of an image displayed on the plasma display panel shown in FIG. 1;

FIG. 12 is a diagram showing a write pattern in subfields SF1 to SF3 for displaying the image shown in FIG.

FIG. 13 is a view showing a write pattern in a subfield SF4 for displaying the image shown in FIG. 11;

FIG. 14 is a block diagram showing a configuration of a plasma display device according to a second embodiment of the present invention.

15 is a block diagram showing a configuration of a temperature estimator shown in FIG.

FIG. 16 is a block diagram showing a configuration of another example of the temperature estimator.

FIG. 17 is a block diagram showing a configuration of a plasma display device according to a third embodiment of the present invention.

18 is a block diagram showing a configuration of the image signal controller shown in FIG.

FIG. 19 is a diagram showing an example of another image displayed on the plasma display panel.

20 is a diagram showing a write pattern in subfields SF1 and SF2 for displaying the image shown in FIG.

FIG. 21 is a diagram showing a write pattern in subfields SF3 and SF4 for displaying the image shown in FIG.

FIG. 22 is a view showing an example of an image displayed on the plasma display panel shown in FIG. 19;

FIG. 23 is a diagram showing a write pattern in subfields SF1 and SF2 for displaying the image shown in FIG. 22;

FIG. 24 is a view showing a write pattern in a subfield SF3 for displaying the image shown in FIG. 22;

FIG. 25 is a view showing a write pattern in a subfield SF4 for displaying the image shown in FIG. 22;

[Explanation of symbols]

 1, 1a, 1b Image signal controller 2 Image-subfield associator 3 Subfield processor 4, 4a, 4b Temperature estimator 5 Scanning / sustaining drive circuit 6 Data drive circuit 7 Plasma display panels 11-13, 12b, 13b Delayer 14 Subtractor 15-17 Multiplier 18, 11b Adder 19, 17b Selector 20, 21, 14b, 16b Comparator 22 Judgment circuit 40 Block division circuit 41, 41a-41d Peripheral pixel operation circuit 42, 42a- 42d addition circuit 43, 43a to 43d temperature estimation circuit 47 maximum value detection circuit 15b lower bit replacement

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/66 101 G09G 3/28 J (72) Inventor Tomoko Morita 1006 Odakadoma, Kadoma City, Osaka Matsushita Electric F-term (reference) in Sangyo Co., Ltd. 5C058 AA11 BA30 BA35 5C080 AA05 BB05 DD19 DD20 DD27 EE26 EE29 FF12 JJ02

Claims (16)

[Claims] 1. A display device for displaying an image according to an input image signal, comprising: a display unit including a plurality of pixels arranged in a matrix; and a drive unit for driving a selected pixel in the display unit. Means, a temperature estimating means for estimating a temperature estimation value corresponding to the temperature of the driving means from the image signal, and converting the image signal into an image signal for suppressing a rise in the temperature of the driving means according to the temperature estimation value. A display device, comprising: an image signal conversion unit that drives a selected pixel in the display unit according to the image signal converted by the image signal conversion unit. 2. An image signal of one field is divided into a plurality of sub-field image signals for driving a pixel selected for each sub-field to perform gradation display. 2. The display device according to claim 1, further comprising: a sub-field conversion unit configured to convert the temperature of the driving unit from the sub-field image signal. 3. The display according to claim 2, wherein the display unit includes a plurality of address electrodes forming the pixels, and the driving unit includes an address electrode driving unit that drives the address electrodes. apparatus. 4. The temperature estimating means performs a logical operation on each data of the sub-field image signal between pixels of the display unit, and obtains the temperature estimation value based on a sum of operation results. Item 4. The display device according to item 2 or 3. 5. The temperature estimating means integrates the sum of the operation results for each field, and subtracts the heat radiation amount of the driving means from the integrated value to obtain the temperature estimation value. Item 5. The display device according to Item 4. 6. The display unit is divided into a plurality of blocks, the driving unit includes a plurality of driving units provided for each of the blocks, and the temperature estimating unit includes a temperature estimation value for each of the driving units. The display device according to claim 1, wherein: 7. The display device according to claim 6, wherein the temperature estimating unit outputs a maximum temperature estimated value among a plurality of temperature estimated values obtained for each of the driving units as a temperature estimated value. . 8. The image signal converting unit converts the image signal into an image signal that suppresses a temperature rise of the driving unit by filtering the image signal between neighboring pixels. Item 8. The display device according to any one of Items 1 to 7. 9. The display device according to claim 8, wherein the image signal conversion unit increases the effect of the filtering as the temperature estimation value increases. 10. The image signal converting means filters the image signal between neighboring pixels when a difference between adjacent pixels of the image signal is equal to or larger than a predetermined reference value, thereby obtaining the image signal. The display device according to claim 1, wherein the signal is converted into an image signal that suppresses a rise in temperature of the driving unit. 11. The image signal conversion unit converts the image signal into an image signal that suppresses a temperature rise of the driving unit by making at least a part of a plurality of bits of the subfield image signal identical to peripheral pixels. The display device according to claim 2, wherein conversion is performed. 12. The image signal converting means for replacing lower bits of a subfield image signal of a pixel having a larger value between neighboring pixels with lower bits of a subfield image signal of a pixel having a smaller value. 12. The display device according to item 11. 13. The image signal converting means replaces lower bits of a subfield image signal of a pixel having a larger value between neighboring pixels with lower bits of a subfield image signal of a pixel having a smaller value. The display device according to claim 11, wherein a value corresponding to a difference between the replaced value and the original value is added to peripheral pixels. 14. The display device according to claim 11, wherein said image signal conversion means increases the number of bits to be identified as the temperature estimation value increases. 15. A display for displaying an image in accordance with an input image signal, comprising: a display unit including a plurality of pixels arranged in a matrix; and driving means for driving a selected pixel in the display unit. A method for driving a device, comprising: estimating a temperature estimation value corresponding to a temperature of the driving unit from the image signal; and controlling the image signal to suppress a temperature rise of the driving unit in accordance with the temperature estimation value. A method for driving a display device, the method comprising: converting a selected pixel in the display unit by the driving unit in accordance with the converted image signal. 16. An image signal of one field is divided into a plurality of subfield image signals for driving a pixel selected for each subfield to perform gradation display. The method of driving a display device according to claim 11, further comprising: converting the temperature of the driving unit from the subfield image signal.