JP2005345888A - Electro-optical device and control method thereof, image processor, and electronic appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily determine correction values to be applied to corrections of gradation characteristics of respective electro-optical elements. <P>SOLUTION: This image processor 31 has a correction value acquiring circuit 52 which supplies an image signal VID, representing gradations of respective pixels P to an electrooptical panel having the plurality of pixels P and acquires correction values Ar, Ag, and Ab individually for groups, formed by classifying the plurality of pixels P according to display colors and a correction-by-group circuit 51, which corrects the image signal VID to be supplied to the respective pixels P according to the correction values that the correction value acquiring circuit 52 acquires as to the groups that the respective pixels P belong to. Corrections by the correction-by-group circuit 51 are made so as to be invalid according to the correction allowance/disallowance signal Sa supplied from a host device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electro-optical device including an electro-optical element such as an OLED (Organic Light Emitting Diode) element, and more particularly to a technique for correcting an image signal designating a gradation of each electro-optical element.

Electro-optical devices that display images using electro-optical elements are widely used as display devices for various electronic devices. In this type of electro-optical device, securing an intended white balance for a display image is an important issue for improving display quality. Against this background, for example, in Patent Document 1 and Patent Document 2, an image signal that specifies the gradation of each electro-optical element is corrected independently for each display color such as red, green, and blue. A configuration is proposed. According to this configuration, white balance can be improved by appropriately adjusting the correction value for each display color.
JP 2001-343940 A (paragraph 0029) JP 2003-29724 A (paragraph 0040 and FIG. 8)

  However, although it is possible to independently select the correction value for each display color, it is not easy to select each correction value with high accuracy so as to achieve the desired white balance. The present invention has been made in view of such circumstances, and an object thereof is to easily and accurately determine a correction value applied to correction of gradation characteristics of each electro-optical element.

  In order to solve the above-described problems, an image processing apparatus according to the present invention is an image processing apparatus that supplies an image signal indicating a gradation of each electro-optical element to an electro-optical apparatus having a plurality of electro-optical elements. Acquisition means (for example, “correction value acquisition circuit 52” in an embodiment to be described later) for individually acquiring a correction value for each of a plurality of groups obtained by dividing the plurality of electro-optical elements, and is supplied to each electro-optical element. Correction means for correcting an image signal (that is, an image signal designating the gradation of each electro-optical element) based on a correction value acquired by the acquisition means for a group to which the electro-optical element belongs (for example, “group in an embodiment described later” And an invalidating means for invalidating the correction by the correcting means when a signal instructing invalidation of the correction is input.

  According to this configuration, the image signal is supplied to each electro-optical element after the correction by the correction unit is invalidated, and each correction value is adjusted based on the gradation actually displayed at this time, thereby obtaining the expected value. The display characteristics can be easily obtained. Note that the electro-optical element in the present invention is an element having a property that an optical characteristic is changed by supplying a voltage signal or a voltage signal. Typical examples of such elements include OLED elements such as organic EL (regardless of polymer, low molecule and dendrimer) and light emitting polymers, but the scope to which the present invention can be applied is It is not limited to. In the present invention, “invalidating correction by the correction unit” means that the image signal input to the correction unit matches the image signal output from the correction unit. For example, if the correction means is a means for multiplying the image signal by the correction value, the correction by the correction means “invalidated” means that the correction value is set to “1”. Even when a correction value is selected in the same manner as when the correction is valid, if the image signal is output without executing the correction using the correction value, the correction by the correction means is performed. It can be said that it has been disabled.

  In a more specific aspect, each of the plurality of electro-optical elements displays one of a plurality of display colors. In this aspect, the acquisition unit acquires the correction value for each of the plurality of groups obtained by dividing the plurality of electro-optic elements for each display color. According to this aspect, the image signal is corrected based on the individual correction value for each display color, which is particularly suitable for adjusting the white balance of the display image.

  A mode in which the plurality of electro-optical elements are divided into groups is arbitrary. For example, when the present invention is applied as an image processing apparatus of an electro-optical device formed by connecting a plurality of sub-panels each having an electro-optical element arrayed, the plurality of electro-optical elements are divided into groups for each sub-panel. The In this case, the acquisition unit acquires the correction value for each of the plurality of groups obtained by dividing the plurality of electro-optical elements for each sub-panel. In this aspect, since the image signal is corrected based on the individual correction value for each sub-panel, it is suitable for adjusting the display characteristics of the electro-optical device as a whole.

  In another aspect of the present invention, in addition to correction means for correcting an image signal for each group of electro-optic elements, the image signals supplied to all the electro-optic elements (that is, regardless of group distinction). ) Common correction means (for example, “non-linearization circuit 4” in an embodiment to be described later) for performing common correction is provided. In other words, the common correction unit is a unit that corrects an image signal supplied to each of the plurality of electro-optical elements based on a common correction value, and is disposed in either the preceding stage or the subsequent stage of the above-described correction unit. The common correction unit corrects each image signal so that the level of the image signal output from the common correction unit changes nonlinearly with respect to the change in the level of the image signal input to the common correction unit. Means may be employed. A typical example of such correction is gamma correction.

  The electro-optical device according to the present invention includes the image processing device according to each aspect described above. More specifically, this electro-optical device individually acquires correction values for each of a plurality of electro-optical elements each having a gradation indicated by an image signal and a plurality of groups obtained by dividing the plurality of electro-optical elements. An acquisition unit, a correction unit that corrects an image signal supplied to each electro-optical element based on a correction value acquired by the acquisition unit for a group to which the electro-optical element belongs, and a signal that instructs invalidation of correction are input. Then, invalidating means for invalidating correction by the correcting means is provided. The electro-optical device is employed as a display device for various electronic devices, for example.

  Furthermore, the electro-optical device control method according to the present invention includes a first process of displaying a predetermined image on each electro-optical element after invalidating the correction by the correction unit, and inputting a correction value for each group to the acquisition unit. And then a second step of making the correction by the correction means effective. According to this method, since the predetermined image is displayed after the correction by the correction unit is invalidated in the first process, a correction value that ensures the desired display characteristics for the electro-optical device is easily determined. be able to. In the first step of this method, it is preferable that the correction value is determined according to the state of each electro-optic element when a predetermined image is displayed. Further, in the first process, it is desirable to execute a process for displaying a predetermined image only on the electro-optic elements belonging to each group for each group. By so doing, it is possible to select a suitable correction value for each group of electro-optic elements, so that it is possible to ensure the desired display characteristics for each group.

<1. First Embodiment>
First, an embodiment in which the present invention is applied to an electro-optical device using an OLED element as an electro-optical element will be described. FIG. 1 is a block diagram showing a configuration of an electro-optical device D according to the first embodiment of the present invention. As shown in the figure, the electro-optical device D includes an electro-optical panel 1 that displays an image, and a control device 3 arranged in the preceding stage. Among them, the electro-optical panel 1 extends in the X direction and is connected to the scanning line driving circuit 21 and is connected to the data line driving circuit 23 and extends in the Y direction orthogonal to the X direction. A plurality of data lines 13. A pixel P is arranged at each intersection of the scanning line 11 and the data line 13. Accordingly, these pixels P are arranged in a matrix in the display area Ad over the X direction and the Y direction. Each pixel P is assigned one of red (R), green (G), and blue (B). In the present embodiment, a configuration in which pixels P of the same color are arranged in the Y direction (so-called stripe arrangement) is illustrated.

  The scanning line driving circuit 21 is a circuit for sequentially selecting the scanning lines 11. That is, the scanning line driving circuit 21 outputs a scanning signal that sequentially becomes an active level for each horizontal scanning period to each scanning line 11. On the other hand, the data line driving circuit 23 is a circuit that outputs a data signal having a voltage corresponding to the gradation to be displayed by each pixel P to each data line 13 during a period in which each scanning line 11 is selected.

  As shown in FIG. 1, each of the plurality of pixels P includes an OLED element 15 that emits light in a color assigned to the pixel P, and a pixel circuit (not shown) for controlling the behavior of the OLED element 15. Have Each OLED element 15 is an electro-optical element that emits light with luminance according to the current supplied from the pixel circuit. The pixel circuit includes a capacitive element that holds the voltage of the data signal supplied to the data line 13, and supplies a current corresponding to the voltage held in the capacitive element to the OLED element 15 (so-called voltage programming method). The pixel circuit of each pixel P includes a capacitive element that holds a voltage corresponding to the current flowing through the data line 13 and supplies a current corresponding to the voltage held in the capacitive element to the OLED element 15 ( A so-called current programming scheme) may also be employed.

  On the other hand, the control device 3 shown in FIG. 1 controls the operation of the electro-optical panel 1 by outputting various control signals such as a horizontal synchronizing signal and a vertical synchronizing signal to the scanning line driving circuit 21 and the data line driving circuit 23. Means. The control device 3 includes an image processing device 31. The image processing device 31 performs predetermined processing on the image signal VID and outputs the processed signal to the data line driving circuit 23. The image signal VID is a digital signal that designates the display gradation of each pixel P (that is, the luminance of the OLED element 15), and is received from various host devices (not shown) such as a CPU of an electronic device in which the electro-optical device D is mounted. Supplied to the image processing device 31.

  FIG. 2 is a block diagram showing the configuration of the image processing device 31 and the data line driving circuit 23 at the subsequent stage. As shown in the figure, the image processing apparatus 31 includes a non-linearization circuit 4, a group-specific correction circuit 51, and a correction value acquisition circuit 52. Among these, the non-linearization circuit 4 is means for imparting non-linear characteristics to the image signal VID supplied from the host device. More specifically, the nonlinear circuit 4 performs gamma correction on the image signal VID. FIG. 3 is a graph showing the relationship between the gradation value indicated by the image signal VID input from the host device to the image processing device 31 and the gradation value indicated by the image signal VID output from the non-linearization circuit 4. As shown in the figure, the non-linearization circuit 4 is designated by the image signal VID output from the non-linearization circuit 4 in response to a change in the gradation value specified by the image signal VID input from the host device. The image signal VID is corrected so that the gradation value to be changed changes nonlinearly. At this time, the mode of correction applied to the image signal VID is designated by a coefficient (so-called gamma value) n. This coefficient (hereinafter referred to as “non-linear coefficient”) n is a coefficient designated by the host device in accordance with an instruction from the user, and is common regardless of which light emitting color gradation the image signal VID indicates. Numeric values are applied.

  On the other hand, the group-specific correction circuit 51 shown in FIG. 2 is means for correcting the image signal VID for each group obtained by dividing the plurality of pixels P according to the respective emission colors, and includes three correction circuits 511r, 511g, and 511b. The image signal VID output serially from the non-linear circuit 4 is branched into three systems corresponding to the total number of emission colors of each OLED element 15. Of these, an image signal (hereinafter simply referred to as “image signal corresponding to red”, which designates the gradation of the pixel P corresponding to red) VID is supplied to the correction circuit 511r. The image signal VID corresponding to green is supplied to the correction circuit 511g, and the image signal VID corresponding to blue is supplied to the correction circuit 511b. The correction circuits 511r, 511g, and 511b are circuits that correct the input image signal VID based on the correction values Ar, Ag, and Ab, respectively. More specifically, the correction circuit 511r multiplies the image signal VID corresponding to red by the correction value Ar and outputs the result, and the correction circuit 511g outputs the correction value Ag to the image signal VID corresponding to green. The correction circuit 511b multiplies the image signal VID corresponding to blue by the correction value Ab and outputs the result. As described above, in the non-linearization circuit 4 described above, the image signal VID is subjected to a common correction (non-linear characteristic addition) regardless of the emission color, whereas in the group-specific correction circuit 51, the image signal VID is corrected separately (correction for each group) for each emission color of each pixel P.

  The correction value acquisition circuit 52 individually acquires the correction values Ar, Ag, and Ab applied to the correction by the correction circuits 511r, 511g, and 511b from the host device, and outputs the correction values to the correction circuits 511r, 511g, and 511b. Circuit. More specifically, the correction value acquisition circuit 52 outputs correction values Ar, Ag, and Ab written in a memory (not shown) (for example, a rewritable ROM) to the correction circuits 511r, 511g, and 511b, respectively. The correction values Ar, Ag and Ab stored in are updated in accordance with instructions from the host device. As described above, in the present embodiment, the correction based on the separate correction values Ar, Ag, and Ab is executed for the image signal VID corresponding to each light emission color, so that each correction value Ar, Ag, and Ab is appropriately set. It is possible to easily adjust the white balance by selecting to.

  As shown in FIG. 2, the signal Sa is input to the image processing device 31 from the host device. This signal (hereinafter referred to as “correction permission / denial signal”) Sa is a signal for designating whether the correction of the image signal VID by the correction circuits 511r, 511g, and 511b is valid or invalid. When the correction permission / rejection signal Sa becomes an active level and the correction is instructed, the group-specific correction circuit 51 corrects and outputs the image signal VID based on the correction values Ar, Ag, and Ab as described above. . On the other hand, when the correction permission signal Sa is inactive and the invalidation of the correction is instructed, the correction value acquisition circuit 52 does not depend on the contents of the correction values Ar, Ag and Ab designated by the host device. The correction values Ar, Ag, and Ab supplied to the correction circuits 511r, 511g, and 511b are all set to “1”. Therefore, when the correction permission / rejection signal Sa becomes an inactive level, the image signal VID input from the non-linearization circuit 4 to the group-specific correction circuit 51 is output as it is (that is, correction is invalidated). That is, the correction value acquisition circuit 52 functions as means for invalidating the correction by the group-specific correction circuit 51.

  As shown in FIG. 2, the data line driving circuit 23 includes a D / A conversion circuit 231 that converts the digital image signal VID into a data signal that is an analog signal. The voltage level range (hereinafter referred to as “output range”) of the data signal output from the D / A conversion circuit 231 to each data line 13 is changed according to the coefficient k. This output range is the range from the level (voltage) of the data signal when the lowest gradation is specified by the image signal VID to the level of the data signal when the highest gradation is specified by the image signal VID. is there. Therefore, the contrast of the display image can be adjusted by changing the range coefficient k. That is, the larger the range coefficient k is, the wider the output range is (that is, the interval between the gradations is larger), and the contrast of the display image is increased. The smaller the range coefficient k is, the narrower the output range is (that is, the interval between each gradation is For example, the contrast of the display image decreases. This range coefficient k is designated by the host device in response to an instruction from the user, similarly to the nonlinear coefficient n.

Next, a procedure for adjusting the display characteristics of the electro-optical panel 1 will be described with reference to the flowchart of FIG.
First, the correction permission / rejection signal Sa is set to an inactive level in accordance with an instruction from the user to the host device, thereby invalidating the correction by the group-specific correction circuit 51 (step S1). That is, the correction values Ar, Ag, and Ab output from the correction value acquisition circuit 52 to the correction circuits 511r, 511g, and 511b are all set to “1”. Next, the nonlinear coefficient n and the range coefficient k are set to predetermined values (step S2). For example, the nonlinear coefficient n is set to “2” and the range coefficient k is set to “1”.

  Next, an image signal VID representing a predetermined image is input from the host device to the image processing device 31 while the correction by the group-specific correction circuit 51 is invalidated (step S3). This image signal VID is selected so that, for example, only the red pixel P of the plurality of pixels P emits light with a predetermined luminance, while the luminance of the green and blue pixels P becomes zero. The image signal VID is given non-linear characteristics by the non-linearization circuit 4 as shown in FIG. 3, and then passes through the group-specific correction circuit 51 as it is (that is, without any correction) to drive the data line. It is output to the circuit 23. A characteristic I1 in FIG. 5 indicates the relationship between the gradation value indicated by the image signal VID input to the image processing device 31 and the gradation value indicated by the image signal VID output from the group-specific correction circuit 51. In the figure, only the characteristic I1 related to the image signal VID corresponding to red is shown. As shown in FIG. 5, the image signal VID at this stage is output to the electro-optical panel 1 while maintaining the characteristics corrected by the non-linearization circuit 4 (characteristics in FIG. 3). As a result of the above operation, only the pixel P corresponding to red among the plurality of pixels P of the electro-optical panel 1 emits light with a predetermined luminance. Then, the luminance of the display area Ad in this state is measured by a predetermined measuring device (not shown). Thereafter, the same processing is executed for green and blue. That is, an image signal VID for emitting only one OLED element 15 of a light emitting color at a predetermined gradation is input from the host device to the image processing device 31, and the luminance of the display area Ad at this time is measured by the measuring device. (Step S3).

  After the luminance ratio of red, green and blue is measured by the above processing, this ratio (hereinafter referred to as “measured luminance ratio”) and a predetermined ratio (hereinafter referred to as “target”) for ensuring the desired white balance. (Referred to as “luminance ratio”), and correction values Ar, Ag, and Ab are determined based on the comparison result (step S4). For example, assume that the target luminance ratio is “red: green: blue = 10: 50: 40” and the measured luminance ratio is “red: green: blue = 20: 50: 60”. In this case, the red correction value Ar is set to “1/2 (= 10/20)”, the green correction value Ag is set to “1 (= 50/50)”, and the blue correction value Ab is set. Is set to “2/3 (= 40/60)”. These correction values Ar, Ag, and Ab are instructed to the correction value acquisition circuit 52 of the image processing device 31 by being input to the host device by the user. The correction value acquisition circuit 52 updates the memory with the new correction values Ar, Ag, and Ab thus instructed.

  Next, the correction permission / rejection signal Sa is set to the active level in accordance with an instruction from the user to the higher-level device, whereby the correction by the group-specific correction circuit 51 is validated (step S5). In this state, the image signal VID input to the image processing device 31 is given nonlinear characteristics by the nonlinear circuit 4, and the correction values Ar, Ag, and Ab for each emission color by the correction circuits 511r, 511g, and 511b. After being multiplied, it is output to the electro-optical panel 1. The characteristic I2 in FIG. 5 indicates the gradation value indicated by the image signal VID (here, the image signal VID corresponding to red) input to the image processing device 31 in this state and the image signal VID output from the group-specific correction circuit 51. Shows the relationship with the gradation value indicated by. Since the red correction value Ar is set to “1/2” in step S5 described above, the gradation indicated by the image signal VID output from the group-specific correction circuit 51 as shown by the characteristic I2 in FIG. The value is “½” of the gradation value (characteristic I1) indicated by the image signal VID when the correction is invalidated. Since the same correction is applied to the image signal VID corresponding to green and blue, the luminance ratio of each pixel P is “red: green: blue = 10: 50: 40”, which is the target luminance ratio. It almost agrees.

  As described above, in the present embodiment, the correction performed separately for each emission color of the pixel P with respect to the image signal VID can be invalidated collectively, so that an image is displayed in this state. By doing so, it is possible to easily determine the correction values Ar, Ag and Ab so as to ensure the desired white balance. Moreover, in the present embodiment, in addition to correction by the group-specific correction circuit 51, nonlinear characteristics corresponding to the nonlinear coefficient n are given to the image signal VID, and the output range of the data signal is arbitrarily set according to the range coefficient k. Therefore, there is an advantage that a desired display characteristic can be realized with high accuracy as compared with the configuration in which only the correction by the group-specific correction circuit 51 is performed on the image signal VID.

<2. Second Embodiment>
Next, an electro-optical device D according to a second embodiment of the invention will be described. In the first embodiment, the configuration in which the non-linearization circuit 4 is arranged in front of the group-specific correction circuit 51 is exemplified. On the other hand, in the present embodiment, the non-linearization circuit 4 is arranged at the subsequent stage of the group-specific correction circuit 51. In the electro-optical device D according to the present embodiment, elements that are the same as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 6 is a block diagram illustrating configurations of the image processing device 31 and the data line driving circuit 23 in the electro-optical device D according to the present embodiment. As shown in the figure, in the electro-optical device D, the data line driving circuit 23 includes a non-linearization circuit 4 in addition to the D / A conversion circuit 231. The operation of these circuits and the configuration of the group-specific correction circuit 51 are the same as those in the first embodiment. On the other hand, the non-linear circuit 4 is not provided in the image processing apparatus 31.

  In this configuration, the image signal VID supplied from the host device is branched into three systems corresponding to the total number of emission colors of each OLED element 15, and then input to the correction circuits 511r, 511g, and 511b, respectively. The image signal VID is corrected for each emission color. More specifically, as shown by the characteristic I1 in FIG. 7, when the correction is invalidated, the image signal VID supplied from the host apparatus is output as it is from the group-specific correction circuit 51. On the other hand, as shown as characteristic I2 in the figure, when the correction is valid, the correction value Ar is set for the image signal VID corresponding to each emission color (here, the image signal VID corresponding to red). After being multiplied, it is output to the data line driving circuit 23. On the other hand, FIG. 8 shows the relationship between the gradation value indicated by the image signal VID input to the data line driving circuit 23 and the gradation value indicated by the image signal VID output from the non-linearization circuit 4, and the group-specific correction circuit 51. FIG. 6 is a diagram illustrating a case where the correction according to the above is invalid (characteristic I1) and a case where the correction is valid (characteristic I2). As shown in the figure, the image signal VID is given a non-linear characteristic by the non-linearization circuit 4 of the data line drive circuit 23 regardless of whether the correction by the group-specific correction circuit 51 is invalid or valid. Is done.

  The display characteristics of the electro-optical device D according to the present embodiment are adjusted by the same procedure (FIG. 4) as in the first embodiment. Also in this embodiment, the correction separately performed for each light emission color of the pixel P with respect to the image signal VID to each pixel P can be invalidated collectively, and thus the same as in the first embodiment. An effect is obtained.

<3. Third Embodiment>
Next, with reference to FIG. 9, an electro-optical device D according to a third embodiment of the invention will be described. In the electro-optical device D according to the present embodiment, elements that are the same as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in the figure, the electro-optical panel 1 in this embodiment has a configuration in which four sub-panels Ds1, Ds2, Ds3, and Ds4 are connected to each other. Each sub-panel Dsi (i is an integer satisfying 1 ≦ i ≦ 4) has the same configuration as that of the electro-optical panel 1 shown in the first embodiment. That is, each sub-panel Dsi has a scanning line driving circuit 21 to which a plurality of scanning lines 11 are connected, a data line driving circuit 23 to which a plurality of data lines 13 are connected, and scanning lines 11 and data lines 13 at each intersection. And a plurality of pixels P arranged. The data line driving circuit 23 of each sub-panel Dsi is connected to the image processing device 31 of the control device 3. In the first and second embodiments, the configuration in which the image signal VID is separately corrected for each group divided according to the emission color has been exemplified. On the other hand, in the present embodiment, all the pixels P included in the electro-optical panel 1 are divided into groups for each sub-panel Ds, and based on a separate correction value for each image signal VID of the pixels P belonging to each group. The correction is applied.

  FIG. 10 is a block diagram showing the configuration of the image processing apparatus 31 and the configuration of the data line driving circuit 23 of each sub-panel Dsi in this embodiment. As shown in the figure, in this embodiment, a D / A conversion circuit 231 similar to that in the first embodiment is provided for each data line driving circuit 23. However, in this embodiment, separate range coefficients ki (k1, k2, k3, k4) are designated for the D / A conversion circuit 231 of each sub-panel Dsi.

  On the other hand, the image processing apparatus 31 includes four correction units U1, U2, U3, and U4, each corresponding to a separate sub-panel Dsi. The image signal VID output serially from the host device is branched into four systems each having a separate sub-panel Dsi as an output destination, and the i-th system is input to the correction unit Ui. That is, the image signal VID to be supplied to the sub panel Ds1 is input to the correction unit U1, and the image signal VID to be supplied to the sub panel Ds2 is input to the correction unit U2.

  Each correction unit Ui has a non-linearization circuit 4 and a correction circuit 511. Among these, the nonlinear circuit 4 has the same configuration as the nonlinear circuit 4 of the first embodiment. However, in this embodiment, a separate nonlinear coefficient ni (n1, n2, n3, n4) is designated for the nonlinear circuit 4 of each correction unit Ui. The non-linearization circuit 4 of the correction unit Ui gives a non-linear characteristic corresponding to the non-linear coefficient ni to the image signal VID.

  On the other hand, the correction circuits 511 of the correction units U1, U2, U3, and U4 are circuits that correct the image signal VID based on the correction values B1, B2, B3, and B4, respectively. That is, the correction circuit 511 of the correction unit Ui multiplies the image signal VID input from the non-linearization circuit 4 (that is, the image signal VID specifying the gradation of the pixel P of the sub-panel Dsi) by the correction value Bi and outputs it. To do. Each correction value Bi is designated by the correction value acquisition circuit 52 in accordance with an instruction from the host device, as in the first embodiment. Thus, in the present embodiment, separate correction is performed on the image signal VID of the pixel P belonging to each sub-panel Dsi. The group-specific correction circuit 51 shown in FIG. 10 includes four correction circuits 511. Also in the present embodiment, the validity / invalidity of correction by the group-specific correction circuit 51 can be switched according to the level of the correction permission / rejection signal Sa supplied from the host device, as in the first embodiment. . That is, when the correction permission / rejection signal Sa becomes an inactive level, the correction value acquisition circuit 52 sets all of the correction values B1 to B4 to “1”.

  Also in this embodiment, the display characteristics of each sub-panel Dsi are adjusted by the procedure of FIG. 4 as in the first embodiment. That is, first, the correction by the group-specific correction circuit 51 is invalidated (step S1), and the nonlinear coefficients n1 to n4 and the range coefficients k1 to k4 are set to predetermined values (step S2). A predetermined image is displayed only on the sub panel Dsi, and the luminance in the display area Ad of the sub panel Ds is measured (step S3). Then, the luminance ratio (measured luminance ratio) of each sub-panel Dsi is calculated by executing the process of step S3 for all the sub-panels Ds1 to Ds4, and according to the comparison result between the measured luminance ratio and the target luminance ratio. Correction values B1 to B4 are determined. By inputting the correction values B1 to B4 to the correction value acquisition circuit 52 and then enabling the correction by the group-specific correction circuit 51 (step S5), a good display in which the luminance balance is ensured for the plurality of sub-panels Dsi is obtained. An image can be displayed on each sub-panel Dsi under the characteristics.

  Here, the configuration in which the non-linearization circuit 4 is arranged in the preceding stage of the group-specific correction circuit 51 is illustrated here, but the configuration in which the non-linearization circuit 4 is arranged in the subsequent stage of the group-specific correction circuit 51 as in the second embodiment. Can also be employed. For example, as shown in FIG. 11, the data line driving circuit 23 of each sub-panel Dsi may include a non-linearization circuit 4 in addition to the D / A conversion circuit 231.

<4. Modification>
Various modifications can be made to the above embodiments. Specific modifications are as follows. In addition, the structure which combined each said embodiment and each following aspect suitably may be employ | adopted.

(1) The first embodiment and the third embodiment may be combined. For example, in addition to the correction circuits 511 shown in FIG. 10, three correction circuits 511r, 511g, and 511b (each group-specific correction circuit 51 shown in FIG. 1) correct each of the image signals VID corresponding to different emission colors. ) Is used. According to this configuration, it is possible to adjust both the luminance ratio of the sub-panels Ds1 to Ds4 and the luminance ratio of each emission color in each sub-panel Dsi. In this configuration, the correction value acquisition circuit 52 has a correction value Bi multiplied by the image signal VID having each sub panel Dsi as an output destination, and a correction value Ari set for each emission color of each pixel P belonging to each sub panel Dsi. , Agi and Abi. For example, the correction values (B1, Ar1, Ag1, Ab1) are designated for the sub-panel Ds1, while the correction values (B2, Ar2, Ag2, Ab2) are designated for the sub-panel Ds2. Under this configuration, the image signal VID whose output destination is the sub-panel Dsi is corrected based on the correction value B1, and the image signal VID is corrected based on the correction values Ari, Agi, and Abi for each emission color. Applied. Alternatively, the initial values Ar0, Ag0 and Ab0 of the correction values for the respective emission colors are selected in advance in the configuration in which the correction value Bi is specified for each sub-panel Dsi as in the third embodiment, and these values are selected in advance. By multiplying the correction values Ar0, Ag0 and Ab0 by the correction value Bi, the correction values Ari (= Ar0 × Bi), Agi (= Ag0 × Bi), and Abi (= Ab0 ×) for each emission color in each sub-panel Dsi. Bi) may be calculated and applied to the correction.

(2) In each of the above embodiments, the configuration in which the correction value (Ar, Ag, Ab, B1 to B4) is multiplied by the image signal VID has been exemplified. However, the correction contents for the image signal VID are not limited to this. I can't. For example, a configuration in which each correction value is added to the image signal VID or a configuration in which gamma correction using each correction value as a gamma value is performed on the image signal VID may be employed. Therefore, the method for invalidating the correction by the group-specific correction circuit 51 is not limited to the method shown in the above embodiments. For example, in a configuration in which each correction value is added to the image signal VID, the correction by the group-specific correction circuit 51 is invalidated by setting each correction value to “0”.

  Furthermore, the correction of the group-specific correction circuit 51 may be invalidated by a method other than the correction value change. For example, instead of the configuration shown in FIG. 1, as shown in FIG. 12, switches 54a and 54b are arranged at the front stage and the rear stage of the group-specific correction circuit 51, respectively, and transmission is performed so that these switches 54a and 54b are connected. A configuration in which the path 55 is provided can also be adopted. The switch 54a switches the connection destination of the output end of the non-linearization circuit 4 to either the group-specific correction circuit 51 or the transmission path 55, and the switch 54b switches the connection destination of the output end of the image processing device 31 to the group-specific correction circuit 51. And switching to one of the transmission paths 55. In this configuration, when the correction permission / rejection signal Sa is at the active level, the group-specific correction circuit 51 is connected to the non-linearization circuit 4 and the output terminal of the image processing device 31 (the state shown in FIG. 12), and the correction permission / rejection signal. When Sa is at an inactive level, the states of the switches 54a and 54b are switched so that the transmission path 55 is connected to the nonlinear circuit 4 and the output terminal of the image processing apparatus 31. Also with this configuration, as in the above embodiments, when the correction permission / rejection signal Sa is at an inactive level, the image signal VID output from the non-linearization circuit 4 does not undergo correction by the group-specific correction circuit 51 ( That is, it is output to the data line driving circuit 23 (via the transmission line 55). In addition, although the case where the structure of 1st Embodiment was deform | transformed was illustrated here, the same deformation | transformation can be added also about 2nd and 3rd Embodiment. Thus, the mode of the means for invalidating the correction for each group in the present invention is not questioned.

(3) In each of the above embodiments, the configuration in which the image signal VID is corrected by the arithmetic processing using the image signal VID and the correction value is exemplified, but the method for correcting the image signal VID is not limited thereto. Absent. For example, a table in which the image signal VID before correction and the image signal VID after correction are associated is created for each correction value, and when the image signal VID is supplied from the host device, the correction value is acquired at that time. A configuration may be employed in which a table corresponding to the correction value specified by the circuit 52 is specified and the image signal VID associated with the image signal VID is output in this table. However, in this configuration, there is a possibility that the size of the table may be excessive, and therefore, from the viewpoint of reducing the circuit size, a configuration in which the image signal VID is corrected by arithmetic processing as in the above embodiments is desirable.

(4) In each of the above embodiments, the configuration in which the luminance is measured when selecting each correction value is exemplified. However, instead of this configuration or together with this configuration, the current consumption by the OLED element 15 of each pixel P is measured. Configurations can also be employed. Since the luminance of the OLED element 15 is substantially proportional to the current flowing therethrough, the gradation characteristics of each OLED element 15 can be specified by measuring this current. Therefore, for example, by measuring the current consumed by the OLED elements 15 of each group and comparing with the intended current, a suitable correction value can be selected as in the above embodiments.

(5) In the first and second embodiments, the pixel P is divided into groups for each emission color, and in the third embodiment, the pixel P is divided into groups for each sub-panel Dsi. The method of dividing P into groups is arbitrary. For example, in a configuration in which a plurality of data line driving circuits 23 are arranged in one electro-optical panel 1, a configuration may be adopted in which the pixels P connected to one data line driving circuit 23 are grouped into units.

(6) In each of the above embodiments, the configuration in which the control device 3 and the image processing device 31 are hardware separate from the electro-optical panel 1 is illustrated. However, these circuits are mounted on the electro-optical panel 1. Other configurations may also be employed. Further, the control device 3 and the image processing device 31 may be built in the scanning line driving circuit 21 or the data line driving circuit 23.

(7) In each of the above embodiments, the electro-optical device D to which the OLED element 15 is applied as the electro-optical element is illustrated, but the present invention is also applied to other electro-optical devices D. For example, liquid crystal display, field emission display (FED), surface-conduction electron emission display (SED), ballistic electron surface display (BSD), light emission The present invention can also be applied to various electro-optical devices D such as a display device using a diode, or a write head of an optical writing type printer or an electronic copying machine, as in the above embodiments. As described above, the electro-optical element in the present invention is an element having a property that optical characteristics such as transmittance and luminance are changed by application of electrical energy (typically, supply of an electrical signal) The present invention can be applied to all apparatuses (that is, the electro-optical apparatus D) including the electro-optical element.

<5. Application example>
Next, an electronic apparatus to which the electro-optical device according to the invention is applied will be described. FIG. 13 shows a configuration of a mobile personal computer in which the electro-optical device D according to each of the above embodiments is applied to a display device. The personal computer 2000 includes an electro-optical device D as a display device and a main body 2010. The main body 2010 is provided with a power switch 2001 and a keyboard 2002.

  FIG. 14 shows a configuration of a mobile phone to which the electro-optical device D according to each of the above embodiments is applied. A cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and an electro-optical device D as a display device. By operating the scroll button 3002, the screen displayed on the electro-optical panel 1 of the electro-optical device D is scrolled.

  FIG. 15 shows a configuration of a personal digital assistant (PDA) to which the electro-optical device D according to each of the above embodiments is applied. The information portable terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and an electro-optical device D as a display device. When the power switch 4002 is operated, various types of information such as an address book and a schedule book are displayed on the electro-optical panel 1 of the electro-optical device D.

  The electronic apparatus to which the electro-optical device D according to the present invention is applied includes, in addition to those shown in FIGS. 13 to 15, a digital still camera, a liquid crystal television, a viewfinder type, a monitor direct view type video tape recorder, a car Examples include navigation devices, pagers, electronic notebooks, calculators, word processors, workstations, videophones, POS terminals, and devices equipped with touch panels.

1 is a block diagram illustrating an overall configuration of an electro-optical device according to a first embodiment of the invention. FIG. FIG. 2 is a block diagram illustrating a configuration of an image processing apparatus in the electro-optical device. It is a graph which shows the input-output characteristic of a non-linearization circuit among the image processing apparatuses. It is a flowchart which shows the procedure for adjusting a display characteristic. It is a graph which shows the characteristic of the correction circuit classified by group among the image processing apparatuses. FIG. 5 is a block diagram illustrating a configuration of an image processing apparatus in an electro-optical device according to a second embodiment of the invention. It is a graph which shows the characteristic of a correction circuit among the image processing apparatuses. 4 is a graph showing input / output characteristics of a nonlinear circuit of the electro-optical device. FIG. 10 is a block diagram illustrating an overall configuration of an electro-optical device according to a third embodiment of the invention. FIG. 2 is a block diagram illustrating a configuration of an image processing apparatus in the electro-optical device. It is a block diagram which shows the structure of an image processing apparatus among the electro-optical apparatuses which concern on the other aspect of the embodiment. It is a block diagram which shows the structure of the image processing apparatus which concerns on a modification. 1 is a perspective view illustrating a configuration of a personal computer to which an electro-optical device according to the invention is applied. 1 is a perspective view illustrating a configuration of a mobile phone to which an electro-optical device according to the invention is applied. 1 is a perspective view showing a configuration of a portable information terminal to which an electro-optical device according to the invention is applied.

Explanation of symbols

D: Electro-optical device, P: Pixel, 1 ... Electro-optical panel, Ds1, Ds2, Ds3, Ds4 ... Sub-panel, 11 ... Scan line, 13 ... Data line, 15 ... OLED element (Electro-optical) Element), 21... Scanning line drive circuit, 23... Data line drive circuit, 3... Control device, 31... Image processing device, 4. , 51r, 51g, 51b... Correction circuit, 52... Correction value acquisition circuit (acquisition means), 231... D / A conversion circuit, U1, U2, U3, U4 ... correction unit, Sa. , VID: Image signal, Ar, Ag, Ab, B1, B2, B3, B4: Correction value, n, n1, n2, n3, n4: Nonlinear coefficient, k, k1, k2, k3, k4 ... Range factor.

Claims (11)

An image processing apparatus for supplying an image signal indicating a gradation of each electro-optic element to an electro-optic apparatus having a plurality of electro-optic elements,
Obtaining means for individually obtaining a correction value for each of a plurality of groups obtained by dividing the plurality of electro-optic elements;
Correction means for correcting the image signal supplied to each electro-optical element based on the correction value acquired by the acquisition means for the group to which the electro-optical element belongs;
An image processing apparatus comprising: invalidating means for invalidating correction by the correcting means when a signal instructing invalidation of correction is input. Each of the plurality of electro-optical elements displays any one of a plurality of display colors.
The image processing apparatus according to claim 1, wherein the acquisition unit acquires a correction value for each of a plurality of groups obtained by dividing the plurality of electro-optic elements for each display color. The electro-optical device is formed by connecting a plurality of sub-panels each having an electro-optical element,
The image processing apparatus according to claim 1, wherein the acquisition unit acquires a correction value for each of a plurality of groups obtained by dividing the plurality of electro-optic elements for each sub-panel. 4. The apparatus according to claim 1, further comprising: a common correction unit that corrects an image signal supplied to each of the plurality of electro-optical elements based on a common correction value and outputs the corrected image signal to the correction unit. The image processing apparatus according to 1. And a common correction unit that corrects an image signal output from the correction unit and supplied to each of the plurality of electro-optical elements based on a common correction value, and outputs the corrected image signal to the electro-optical device. The image processing apparatus according to claim 1. The common correction unit corrects each image signal so that the image signal output from the common correction unit changes nonlinearly with respect to a change in the image signal input to the common correction unit. The image processing apparatus according to claim 4 or 5. A plurality of electro-optic elements each having a gradation indicated by the image signal;
Obtaining means for individually obtaining a correction value for each of a plurality of groups obtained by dividing the plurality of electro-optic elements;
Correction means for correcting the image signal supplied to each electro-optical element based on the correction value acquired by the acquisition means for the group to which the electro-optical element belongs;
An electro-optical device comprising: invalidating means for invalidating correction by the correcting means when a signal instructing invalidation of correction is input.   An electronic apparatus comprising the electro-optical device according to claim 7 as display means. Acquisition means for individually acquiring a correction value for each of a plurality of groups obtained by dividing a plurality of electro-optical elements; and the acquisition means for an image signal supplied to each of the electro-optical elements for the group to which the electro-optical elements belong A control method for an electro-optical device comprising correction means for correcting based on an acquired correction value,
A first step of displaying a predetermined image on each electro-optic element after invalidating the correction by the correction means;
And a second step of enabling the correction by the correction unit after inputting the correction value for each group to the acquisition unit. The method of controlling an electro-optical device according to claim 9, wherein, in the first step, the correction value is determined according to a state of each electro-optical element when a predetermined image is displayed. . The method for controlling an electro-optical device according to claim 9 or 10, wherein in the first step, a process of displaying a predetermined image only on the electro-optical elements belonging to each group is executed for each group.

Images