JP2006030265A - Image display device and image display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device provided with a user adjustable brightness adjustment means and a contrast adjustment means. <P>SOLUTION: The image display device is provided with a means for calculating corrected image data resulting from compensating an influence of voltage drop, a means for multiplying a gain so that the amplitude of corrected image data is within an input range of a modulation means, the brightness adjustment means for adding or subtracting a user adjustable adjustment value to or from inputted image data, and the contrast adjustment means for changing the gain. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device and an image display method.

  In the following Patent Document 1, it is possible to suitably improve display image degradation due to a voltage drop on the scanning wiring, and at that time, by multiplying the gain so as to be within the input range of the modulation means, an image can be displayed with high quality. Are listed.

  Further, in Patent Document 2 below, by configuring the gradation conversion unit that changes the gradation conversion characteristics by the gain in the previous stage of the configuration that corrects the influence of the voltage drop, it is possible to cancel the saturation characteristics of the phosphor, Thus, it is described that an image is displayed with high quality.

Patent Document 3 below describes that the ABL operation is performed by multiplying the integration result of the input image data by a gain and calculating the current value of the high-voltage power supply.
JP 2003-233344 A JP 2003-241707 A JP 2003-255484 A

  In the image display devices and display methods described in Patent Document 1, Patent Document 2, and Patent Document 3, no suitable offset adjustment and contrast adjustment means and methods when performing voltage drop correction have been shown. . In particular, it has not been shown for cases involving ABL or gradation conversion.

  It is an object of the present invention to provide an image display device and an image display method that realizes suitable offset adjustment and contrast adjustment when performing voltage drop correction.

  The present invention includes a plurality of image forming elements connected to each of a plurality of row wirings and column wirings and arranged in a matrix, a scanning unit connected to the row wirings, and a modulation unit connected to the column wirings. Correction image data calculating means for calculating corrected image data in which the influence of a voltage drop caused by the resistance of the row wiring and scanning means is corrected with respect to input image data; and the amplitude of the corrected image data is modulated Amplitude adjusting means having a function of multiplying a coefficient for adjusting the amplitude of the corrected image data so as to correspond to the input range of the means, and the modulating means is a corrected image whose amplitude has been adjusted by the amplitude adjusting means. An image display device that receives data as an input and outputs a modulation signal to the column wiring, and adjusts an adjustment value adjustable by a user to the input image data. Having a brightness adjustment unit, a contrast adjustment means for changing multiplication operation to the coefficient, the image display apparatus according to claim.

  Alternatively, a plurality of image forming elements connected to each of a plurality of row wirings and column wirings and arranged in a matrix, a scanning unit connected to the row wirings, and a modulation unit connected to the column wirings are provided. An image display method by an image display device, wherein corrected image data obtained by correcting an influence of a voltage drop caused by a resistance component of the row wiring and the scanning unit is calculated with respect to input image data, and the amplitude of the corrected image data Multiplying by a coefficient for adjusting the amplitude of the corrected image data so as to correspond to the input range of the modulating means, and the modulation by the modulating means is the corrected image data whose amplitude is adjusted by the amplitude adjusting means Is an image display method in which a modulation signal is output to the column wiring, and an adjustment value adjustable by the user is added to or subtracted from the input image data. Brightness adjustment, an image display method characterized by performing the contrast adjustment for changing multiplication operation to the coefficient.

  By performing brightness adjustment, which is an addition system, on the input image data, the value based on the light emission luminance of the image display device can be controlled uniformly for all pixels, and the voltage drop for brightness adjustment can be corrected. Adjustment close to the senses can be made. In addition, by adjusting the contrast that is a multiplication system for the coefficient for adjusting the amplitude of the corrected image data, the adjustment value of the amplitude of the input data to the modulation means can be controlled, so that the effect of the contrast adjustment is a voltage drop. It is possible to avoid being canceled by the correction overflow process.

  When the coefficient is always set to a desired value or more, the minimum number of gradations of the input data to the modulation means is secured, so that gradation deterioration due to lowering of contrast can be reduced.

  Since gradation adjustment can be performed based on the actual driving amount by performing contrast adjustment that is a multiplication system on the coefficient for adjusting the amplitude of the corrected image data and outputting the result to the gradation conversion means. Suitable contrast adjustment with a gradation conversion unit can be performed.

  By changing the coefficient based on the input image data that has been subjected to brightness adjustment and the coefficient that has been subjected to contrast adjustment, it is possible to limit the power related to the light emission luminance of the actual image display device. Brightness and contrast can be adjusted.

  That is, it is possible to perform a suitable brightness / contrast adjustment in a voltage drop correction system.

  An image display device according to the present invention is an image of a television receiver or a display device that receives a television signal or a display signal from a computer or the like and displays an image using a display panel having a plurality of image forming elements wired in a matrix. The present invention relates to a display device. In particular, an EL display device or an electron beam display device is a preferred embodiment to which the present invention is applied because it is easily affected by a voltage drop and can require brightness adjustment and contrast adjustment.

  Exemplary embodiments of the present invention will be described below in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

(First embodiment)
The first embodiment of the present invention will be specifically described below.

  FIG. 1 shows the entire signal processing block of this embodiment. In FIG. 1, A1 is a corrected image data calculation unit, A2 is a gain calculation unit, A3 is a multiplier, A4 is a PWM modulator, A5 is a brightness adjustment unit, A6 is an adder, A7 is a contrast adjustment unit, and A8 is a multiplier. is there.

  An interface unit that supplies input image data (not shown) and a display unit that receives a signal from the PWM modulator A4 are connected to the block diagram. The display unit includes a plurality of image forming elements arranged in a matrix in each of a plurality of row wirings and column wirings, and is connected to a scanning unit (not shown) connected to the row wirings.

  The input image data is intended for digital conversion of television signals such as NTSC, PAL, SECAM, HDTV, and VGA signals that are output from computers. Video signals that take CRT emission characteristics into account are linear. It is preferable that the process is performed after conversion to a proper characteristic.

  An offset value designated by the user by the brightness adjustment unit A5 is added to the input image data by the adder A6. The added image data is input to the corrected image data calculation unit A1, and corrected image data in consideration of the influence of the wiring voltage drop of the display unit is output. The corrected image data is input to the gain calculation unit A2, and a coefficient (referred to as gain) for calculating the amplitude corresponding to the input range of the PWM modulator A4 is calculated. This gain is multiplied by a multiplier A8 by a coefficient value designated by the user by the contrast adjustment unit A7. The gain multiplied by the coefficient is input to the multiplier A3, and the corrected image data is multiplied so that the amplitude corresponds to the input range of the PWM modulator A4, and is output to the PWM modulator A4. Details of the corrected image data calculation unit A1, the gain calculation unit A2, the multiplier A3, and the PWM modulator A4 are described in Patent Document 1.

  Here, details of the rightness adjustment will be described below.

  Brightness adjustment usually controls the brightness displayed by adjusting the offset value of data. The input image data is data of a required luminance value that the user wants to output to the display device. Therefore, a uniform offset value can be output to the adder A6 for all the pixels and added to the input image data, so that it can be displayed with brightness close to that of the user.

  For example, when added to the corrected image data, the voltage drop due to the effect of the added value cannot be corrected, and in order to perform the addition considering the correction, an offset value considering the voltage drop is set for each pixel. Since it is necessary to set, it is difficult to perform suitable offset adjustment.

  Here, the brightness adjustment unit A5 can be realized with a general configuration in which an offset value is output by a user via a microcomputer.

  On the other hand, details of contrast adjustment will be described below.

  In contrast adjustment, the coefficient range to be applied to data is usually adjusted to control the displayed luminance range. The gain is a coefficient to be applied to the data so that the amplitude of the corrected image data corresponds to the input range of the PWM modulator A4. Therefore, the displayed luminance range can be suitably controlled by outputting a coefficient value for contrast adjustment to the multiplier A8 and multiplying it by the gain.

  For example, when contrast adjustment is performed on the data before being output to the gain calculation unit, the gain is calculated by the gain calculation unit so that the amplitude of the data after contrast adjustment corresponds to the input range of the PWM modulator A4. Therefore, the effect of contrast adjustment is canceled out. The same applies to the case where the contrast adjustment is performed on the input image data.

  As described above, the normal gain is calculated so that the amplitude of the data corresponds to the input range of the PWM modulator A4. Accordingly, since the state where the contrast adjustment is not performed is the widest state of the displayed luminance range, it is preferable that the coefficient for performing the contrast adjustment is 1 or less (contrast adjustment is only in the direction of decreasing).

  Here, like the brightness adjustment unit A5, the contrast adjustment unit A7 can be realized with a general configuration in which an offset value is output by a user via a microcomputer. Further, the contrast adjustment unit A7 is arranged before (or after) the multiplier A3, and the data multiplied by the coefficient for performing the contrast adjustment is multiplied by the gain (or the contrast adjustment is performed on the data multiplied by the gain). However, it is necessary to multiply all the data by a coefficient for contrast adjustment. With the configuration of the present embodiment, it is sufficient to multiply only the gain, so that it can be realized with a small hardware configuration.

In the embodiments described so far, the configuration in which the gain Gc after contrast adjustment is determined by multiplication of the coefficient value c for performing contrast adjustment and the gain G0 has been shown. The adjusted gain Gc at this time is
Gc = c × G0
It can be expressed as The relationship between the gain Gc after contrast adjustment and the gain G0 and the maximum value CDmax of the corrected image data at this time is shown in FIGS. 6A and 6B. F1A and F1B are the minimum value G0min of the gain G0 when there is no contrast adjustment (the gain calculated when the voltage drop occurs most), F2A and F2B are the characteristics of the gain G0 when there is no contrast adjustment, and F3A and F3B are F2A , The characteristic of the gain G0 when the contrast is lowered from F2B.

  According to this configuration, the smaller the coefficient value c for performing contrast adjustment, the gain characteristics F3A and F3B after contrast adjustment fall below the minimum value G0min of the gain G0 without contrast adjustment, and the corrected image data Will decrease, and the number of display gradations will decrease.

  For example, if the coefficient c for performing contrast adjustment is set to 1/4 for an image whose gain G0 is calculated as 1/5, the corrected image data is reduced to 1/20. That is, if there is corrected image data “20” and corrected image data “30” in this image, for example, “4” and “5” are output to the PWM modulator A4 before contrast adjustment. On the other hand, after contrast adjustment, the same “1” is output to the PWM modulator A4.

On the other hand, as described above, it is preferable that the contrast adjustment in the present invention is performed only in the direction of decreasing, and when the gain G0 is small, the luminance is decreased and displayed. There is little discomfort.
Therefore, the limit value Glim of the gain Gc after adjustment is determined, so that Gc does not fall below Glim, for example,
Gc = c × (G0−Glim) + Glim
This can be realized by a simple configuration as shown in FIG. H1 is a subtracter, H2 is a register storing Glim, H3 is a contrast adjusting unit, H4 is a multiplier, and H5 is an adder. 8A and 8B show the relationship of the gain Gc after contrast adjustment with respect to the gain G0 and the maximum value CDmax of the corrected image data obtained by this configuration. I1A and I1B are the minimum value G0min of the gain G0 when there is no contrast adjustment (the gain calculated when the most voltage drop occurs), I2A and I2B are the characteristics of the gain G0 when there is no contrast adjustment, and I3A and I3B are I2A , The characteristics of the gain G0 when the contrast is lowered from I2B, and I4A and I4B indicate the limit value Glim of the adjusted gain Gc.

  According to this configuration, the variable range of contrast adjustment can be changed by the maximum value CDmax (the gain G0 calculated from the corrected image data of the input image). Therefore, as the coefficient value c for contrast adjustment is reduced, the gain characteristics I3A and I3B after contrast adjustment do not fall below the minimum value G0min of the gain G0 without contrast adjustment. That is, since the limit value Glim of the adjusted gain Gc is at least, suitable contrast adjustment can be performed while suppressing a decrease in the number of display gradations. Here, since the amplitude of the corrected image data does not correspond to the input range of the PWM modulator A4, the adjusted limit value Glim of the gain Gc must be determined to be less than the gain G0min when the voltage drop occurs most. Don't be.

(Second embodiment)
The second embodiment of the present invention will be specifically described below.

  FIG. 2 shows the entire signal processing block of this embodiment. In FIG. 2, B1 is a corrected image data calculation unit, B2 is a gain calculation unit, B3 is a multiplier, B4 is a PWM modulator, B5 is a brightness adjustment unit, B6 is an adder, B7 is a contrast adjustment unit, B8 is a multiplier, B9 is a phosphor saturation correction unit as gradation converting means.

  The configurations and functions of B1 to B8 are the same as A1 to A8 in FIG. Similarly to FIG. 1, an interface unit and a display unit (not shown) are connected.

  In the present embodiment, the offset value designated by the user by the brightness adjustment unit B5 is added to the input image data by the adder B6. The added image data is input to the phosphor saturation correction unit B9 and converted into input charge amount data necessary for the displayed luminance. The input charge amount data is input to the correction image data calculation unit B1, and correction image data considering the influence of the wiring voltage drop of the display unit is output. The corrected image data is input to the gain calculator B2, and a gain is calculated so that the amplitude corresponds to the input range of the PWM modulator B4. This gain is multiplied by a multiplier B8 by a coefficient value designated by the user by the contrast adjustment unit B7. The gain multiplied by the coefficient is input to the multiplier B3, and the corrected image data is multiplied so that the amplitude corresponds to the input range of the PWM modulator B4, and is output to the PWM modulator B4. On the other hand, the gain multiplied by the coefficient is also input to the phosphor saturation correction unit B9.

  Details of the phosphor saturation correction unit B9 will be described below.

  As described in Patent Document 2, the phosphor saturation correction unit B9 is arranged in front of the voltage drop correction unit B1, and phosphor saturation correction is performed based on the actual driving amount, and the displayed luminance is corrected. A suitable display can be performed by outputting the required value of the input charge amount. In this embodiment in which the contrast adjustment is performed on the gain, the gain after the adjustment is a value based on the drive amount. Therefore, in the phosphor saturation correction unit B9, a suitable contrast adjustment with the phosphor saturation correction unit B9 can be performed by changing the saturation characteristic according to the gain after the adjustment.

  Here, even if an offset value was added to the output of the phosphor saturation correction unit B9, the offset adjustment was possible. However, the output of the phosphor saturation correction unit B9 is a required value of the input charge amount with respect to the displayed luminance, and is not a required value of the displayed luminance. Therefore, it is more preferable that the brightness adjustment unit B5 is arranged in front of the phosphor saturation correction unit B9, not behind it.

(Third embodiment)
The third embodiment of the present invention will be specifically described below.

  FIG. 3 shows the entire signal processing block of this embodiment. In FIG. 3, C1 is a corrected image data calculation unit, C2 is a gain calculation unit, C3 is a multiplier, C4 is a PWM modulator, C5 is a brightness adjustment unit, C6 is an adder, C7 is a contrast adjustment unit, C8 is a multiplier, C9 is a phosphor saturation correction unit as a gradation conversion unit, and C10 is an ABL unit as a power limiting unit.

  The configurations and functions of C1 to C9 are the same as B1 to B9 in FIG. Similarly to FIG. 1, an interface unit and a display unit (not shown) are connected.

  In the present embodiment, an offset value designated by the user by the brightness adjustment unit C5 is added to the input image data by the adder C6. The added image data is input to the phosphor saturation correction unit C9 and converted into input charge amount data necessary for the displayed luminance. The input charge amount data is input to the corrected image data calculation unit C1, and corrected image data considering the influence of the wiring voltage drop of the display unit is output. The corrected image data is input to the gain calculator C2, and a gain is calculated so that the amplitude corresponds to the input range of the PWM modulator C4. The multiplier C8 multiplies the gain by a coefficient value designated by the user by the contrast adjustment unit C7. The gain multiplied by the coefficient is input to the ABL unit C10, and the gain changed for power limitation is output based on the integrated value of the output of the phosphor saturation correction unit C9.

  Then, the output of the ABL unit is input to the multiplier C3, and the corrected image data is multiplied so that the amplitude corresponds to the input range of the PWM modulator C4, and is output to the PWM modulator C4. On the other hand, the output of the ABL unit is also input to the phosphor saturation correction unit C9.

  Details of the ABL unit C10 will be described below.

  As described in Patent Document 3, the current value of the high-voltage power supply is calculated to be limited from the integration result of the input image data and the gain, and the current (power) of the actual high-voltage power supply is limited by changing the gain. Therefore, a suitable display can be performed. In this embodiment in which the contrast adjustment is performed on the gain, the gain after the adjustment is a value based on the drive amount. Therefore, the gain multiplied by the coefficient as shown in FIG. 3 is input to the ABL unit C10, and the ABL unit C10 has the configuration shown in FIG. D1 is an integrator, D2 is a multiplier, D3 is a register in which a limit current value is stored, D4 is a comparator, D5 is a limit gain calculator, and D6 is a selector.

  In this configuration, the output of the phosphor saturation correction unit C9 is integrated by the integration unit D1 for one frame, the adjusted value APL is adjusted by the multiplier D2, and the current value of the high-voltage power source is set to be limited. calculate. Then, the desired limit current value stored in the register D3 is compared with the comparator D4, and the gain changed in the limit gain calculation unit D5 and the gain before the change are switched by the selector D6 according to the comparison result. Output. In the limit gain calculation unit D5, for example, a calculation of Ialim / APL is performed so that the current value actually output from the high-voltage power supply does not become larger than the limit current value Ialim. In the phosphor saturation correction unit C9, the saturation characteristics are changed according to the output of the ABL unit C10. As described above, suitable contrast adjustment involving the ABL unit C10 and the phosphor saturation correction unit C9 can be performed.

  For example, when contrast adjustment is performed on a gain limited by ABL, the gain changed to limit the current (power) is arbitrarily adjusted, and a suitable current (power) limit is set. Not done. FIG. 5 shows the actual current (power) characteristics of the high-voltage power supply with respect to Gc (gain after contrast adjustment) × APL when contrast adjustment and ABL are performed. 5A is a characteristic when contrast adjustment is performed first and 5B is performed later. In FIG. 5, E1A and E1B are limiting current (power) values, E2A and E2B are current (power) characteristics when contrast adjustment is not performed, and E3A, E3B, E4A, and E4B are contrast adjusted with respect to E2A and E2B. Current (power) characteristics. It is shown that E3B exceeds the set limit current (power), and E4B shows that the limit is reached before reaching the set limit current (power), which is not preferable.

  Here, the ABL operation was possible even if APL was integrated with respect to the input of the phosphor saturation correction unit C9 and calculated as the current value of the high-voltage power supply. However, the input of the phosphor saturation correction unit C9 is a required luminance value to be displayed, not a required value of the input charge to be displayed. Therefore, it is more preferable that the integration of APL is performed using the data after the phosphor saturation correction unit C9, not before.

  In each of the above embodiments, an example in which gain multiplication is performed on the corrected image data has been described. However, as described in Patent Document 1, the amplitude of the corrected image data is set in the PWM modulator. The same applies to any configuration corresponding to the input range.

  Moreover, although all of the above embodiments have described the PWM modulation method, other methods such as amplitude modulation are equally effective.

It is the figure shown about the whole signal processing block of 1st embodiment. It is the figure shown about the whole signal processing block of 2nd embodiment. It is the figure shown about the whole signal processing block of 3rd embodiment. It is the figure shown about the ABL part used for 3rd embodiment. It is the figure shown about the electric current (electric power) characteristic of the high voltage power supply in the structure used for 3rd embodiment. It is the figure shown about the gain characteristic in the structure used for 1st embodiment. It is the figure shown about the signal processing block of another example of contrast adjustment used for 1st embodiment. It is the figure shown about the gain characteristic in another example of contrast adjustment used for a first embodiment.

Explanation of symbols

A1 correction image data calculation unit A2 gain calculation unit A3 multiplier A4 PWM modulator A5 brightness adjustment unit A6 adder A7 contrast adjustment unit A8 multiplier

Claims (5)

A plurality of image forming elements connected to each of a plurality of row wirings and column wirings and arranged in a matrix, a scanning unit connected to the row wirings, a modulation unit connected to the column wirings,
Corrected image data calculating means for calculating corrected image data obtained by correcting the influence of a voltage drop caused by the resistance of the row wiring and the scanning means on the input image data;
Amplitude adjusting means having a function of multiplying a coefficient for adjusting the amplitude of the corrected image data so that the amplitude of the corrected image data corresponds to the input range of the modulating means;
The modulation means is an image display device that receives the corrected image data adjusted in amplitude by the amplitude adjustment means and outputs a modulation signal to the column wiring. The adjustment value that can be adjusted by a user is input to the modulation means. Brightness adjustment means for adding and subtracting the image data, and contrast adjustment means for multiplying and changing the coefficient,
An image display device characterized by the above.   The image display device according to claim 1, wherein the contrast adjustment unit calculates the change result so that the change result is always equal to or greater than a desired threshold with respect to the input coefficient.   The image display apparatus according to claim 1, further comprising a gradation conversion unit that converts gradation characteristics of the input image data in accordance with the changed coefficient and outputs the converted characteristic to the corrected image data calculation unit.   An average current value corresponding to the light emission luminance of the image display device is calculated based on the integrated value of the input of the corrected image data calculation means and the output from the contrast adjustment means, and the average current value and the output of the contrast adjustment means The image display device according to claim 1, further comprising: a power limiting unit that further changes the coefficient after the change in order to perform power limitation related to the light emission luminance of the image display device. A plurality of image forming elements arranged in a matrix connected to each of a plurality of row wirings and column wirings;
An image display method by an image display device comprising a scanning means connected to the row wiring and a modulation means connected to the column wiring, wherein the resistance of the row wiring and the scanning means with respect to input image data Calculating corrected image data in which the influence of the voltage drop generated by the minute is corrected, and multiplying by a coefficient for adjusting the amplitude of the corrected image data so that the amplitude of the corrected image data corresponds to the input range of the modulation means And
The modulation by the modulation means is an image display method in which the corrected image data amplitude-adjusted by the amplitude adjustment means is input, and a modulation signal is output to the column wiring. An image display method characterized by performing brightness adjustment for adding / subtracting to / from the image data and contrast adjustment for changing the coefficient by multiplication.

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