JP2021051128A - Method for driving electro-optical device, electro-optical device, and electronic apparatus - Google Patents

Abstract

To prevent a reduction in quality of gradation expression in temperature compensation in subfield drive.SOLUTION: A method for driving an electro-optical device includes: dividing a frame period into a plurality of subfields and taking two or more of the plurality of subfields for temperature compensation and the other two or more for gradation control; turning on or off an electro-optical element according to a gradation level in each of the subfields for gradation control; turning on or off the electro-optical element at a first temperature for every gradation level in each of the subfields for temperature compensation; when the temperature is changed to a second temperature different from the first temperature, determining whether the amount of change in gradation for every gradation level is equal to or more than a threshold associated with each of the subfields for temperature compensation; and changing turn-on or off in the subfield corresponding to the gradation level in which the amount of change in gradation is equal to or more than the threshold from turn-on or off at the first temperature.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for driving an electro-optical device, an electro-optical device and an electronic device.

In an electro-optical device that displays an image by an electro-optical element such as a liquid crystal element or an organic EL element, the electro-optical element corresponding to a pixel is driven either on or off for each of a plurality of subfields in which a frame period is divided. The technology is known. In addition, EL is an abbreviation for Electro Luminescence.
In subfield drive, the midtones are represented by varying the percentage of time driven on or off during the frame period. The frame period refers to the period required to display one frame of the video specified by the video data from the host device.

The optical response characteristics of an electro-optical element to an electrical change change depending on the temperature. For example, if the electro-optical element is a liquid crystal element, the viscosity of the liquid crystal changes with respect to the temperature. Therefore, if the temperature is different, the gradation expressed will be different even if the ratio of the on time in the frame period is the same. It ends up.
Therefore, in order to compensate for the change in gradation due to the temperature in the subfield drive, a subfield for temperature compensation is provided separately from the subfield for gradation control, and the subfield for temperature compensation is provided. A technique for variably controlling the period length according to the temperature has been proposed (see, for example, Patent Document 1).

JP-A-2010-177030

However, in the above technique, when the temperature is compensated, the electro-optical element is turned on uniformly regardless of the gradation level, so that there is a problem that the quality of gradation expression tends to deteriorate.

In order to solve one of the above problems, the method for driving the electro-optic device according to one aspect of the present disclosure is provided corresponding to the scanning line and the data line, and is turned on or off when the scanning line is selected. It is a driving method of an electro-optical device that controls an electro-optical element driven according to a corresponding data signal so that the brightness corresponds to a specified gradation level, and divides a frame period into a plurality of subfields. At the same time, two or more of the plurality of subfields are used for temperature compensation, the other two or more are used for gradation control, and the electro-optical element is used in each of the gradation control subfields. The electro-optic element is turned on or off according to the gradation level, and the electro-optic element is turned on or off for each gradation level in each of the subfields for temperature compensation at the first temperature. When the temperature changes to a different second temperature, it is determined whether or not the amount of gradation change for each gradation level is equal to or greater than the threshold value associated with each of the temperature compensation subfields. The on or off in the subfield corresponding to the gradation level which is equal to or higher than the threshold value is changed from the on or off of the first temperature.
Further, the present disclosure can be expressed not only as a driving method of an electro-optical device but also as an electro-optical device.

It is a figure which shows the structure of the liquid crystal panel in an electro-optic device. It is a perspective view which shows the liquid crystal panel. It is sectional drawing which shows the structure of the liquid crystal panel. It is a block diagram which shows the structure of an electro-optic device. It is a figure which shows the equivalent circuit of the pixel in the liquid crystal panel. It is a figure which shows the subfield. It is a figure which shows the example which the transmittance of the liquid crystal element with respect to the gradation level changes with temperature in 1st Embodiment. It is a figure which shows the example of the transmittance change amount for every gradation level. It is a figure which shows the example of the threshold value associated with the subfield for temperature compensation. It is a figure which shows the code of the subfield for compensation with respect to the change of a gradation level. It is a figure which shows the operation of the temperature compensation of an electro-optic device. It is a figure which shows the time transition of the scanning line selected in an electro-optic device. It is a figure which shows the example of the improvement with respect to the temperature change in 1st Embodiment. It is a figure which shows the code of the subfield for temperature compensation with respect to the change of a gradation level in 2nd Embodiment. It is a figure which shows the code of the subfield for temperature compensation with respect to the change of a gradation level in 3rd Embodiment. It is a figure which shows the example of the threshold value associated with the subfield for temperature compensation of the 3rd Embodiment. It is a figure which shows the liquid crystal projector which applied the electro-optic device.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a liquid crystal panel 100 of the electro-optical device according to the embodiment. The liquid crystal panel 100 is a transmissive type and is used, for example, as a light bulb of a liquid crystal projector. The liquid crystal panel 100 is housed in a frame-shaped case 72 that opens in a rectangular display area. One end of the FPC substrate 74 is connected to the liquid crystal panel 100. FPC is an abbreviation for Flexible Printed Circuits. A plurality of terminals 76 are provided at the other end of the FPC board 74, and are connected to a display control circuit omitted in FIG. Data signals and control signals are supplied to the FPC board 74 from the display control circuit via a plurality of terminals 76.

FIG. 2 is a perspective view showing the liquid crystal panel 100, and FIG. 3 is a cross-sectional view taken along the line Hh in FIG.
As shown in these figures, in the liquid crystal panel 100, the element substrate 100a provided with the pixel electrode 118 and the opposing substrate 100b provided with the common electrode 108 are fixed by a sealing material 90 including a spacer (not shown). The structure is such that the electrode forming surfaces are bonded to each other so as to face each other while maintaining the gap between the two, and the liquid crystal 105 is sealed in the gap.

As the element substrate 100a and the facing substrate 100b, substrates having light transmittance such as glass and quartz are used, respectively. As shown in FIG. 2, one side of the element substrate 100a projects from the facing substrate 100b. A plurality of terminals 106 are provided along the one side of the overhanging region. One end of the FPC board 74 is connected to the plurality of terminals 106. The other end of the FPC board 74 is connected to a display control circuit to supply various signals described above.

Pixel electrodes 118 are formed on the surface of the element substrate 100a toward the facing substrate 100b by patterning a transparent conductive layer such as ITO. ITO is an abbreviation for Indium Tin Oxide.
The common electrode 108 provided on the facing substrate 100b is electrically connected to any of the plurality of terminals 106 formed on the element substrate 100a by a conductive material (not shown) such as silver paste, and is temporally connected. A substantially constant voltage Vcom is applied to the.
Further, various elements other than the electrodes are provided on the facing surface of the element substrate 100a and the facing surface of the facing substrate 100b, but they are omitted in the drawing.

FIG. 4 is a block diagram showing the electrical configuration of the electro-optical device 1, and FIG. 5 is a diagram showing an equivalent circuit of the pixel circuit P in the liquid crystal panel 100. As shown in FIG. 4, the electro-optical device 1 includes a display control circuit 3, a temperature detection unit 40, and a liquid crystal panel 100. Of these, the display control circuit 3 includes a processing circuit 30 and a scanning control circuit 35.
The liquid crystal panel 100 has m rows of scanning lines 112 extending in the X direction, n columns of data lines 114 extending in the Y direction, and m rows of scanning lines 112 and n columns. A pixel circuit P formed corresponding to each intersection with the data line 114, a scanning line drive circuit 130, and a data line drive circuit 140 are included. Both m and n are integers of 2 or more.
The temperature detection unit 40 detects the temperature of the liquid crystal panel 100 and outputs the detected temperature information Tmp to the processing circuit 30.

Video data Vid-in and synchronization signal Sync are supplied to the display control circuit 3 from the host device. The video data Vid-in specifies the gradation level of the image to be displayed on the liquid crystal panel 100 for each pixel, for example, 10 bits. Further, the synchronization signal Sync includes a vertical synchronization signal instructing the start of scanning in the pixel arrangement area, a horizontal synchronization signal instructing the start of horizontal scanning in the arrangement area, and one pixel of video data Vid-in. A dot clock signal indicating timing is included.

In the display control circuit 3, the scan control circuit 35 controls the scan line drive circuit 130, the data line drive circuit 140, and the processing circuit 30 based on the synchronization signal Sync. Specifically, the scanning control circuit 35 generates control signals Xctr, Yctr, information Sfn and Sln based on the synchronization signal Sync, and supplies the information Sfn and Sln to the processing circuit 30 to supply the processing circuit. 30 is controlled. Further, the scanning control circuit 35 controls the scanning line driving circuit 130 by the control signal Yctr and the information Sln, and controls the data line driving circuit 140 by the control signal Xctr.

The information Sfn and Sln will be described in detail, but the information Sln is information indicating the scanning line 112 to be selected by the scanning line driving circuit 130. The information Sfn is information indicating which subfield the code corresponding to the code should be output when the scanning line 112 is selected according to the information Sln. Here, the code corresponding to the subfield is binary information indicating that the liquid crystal element included in the pixel circuit P should be driven by either "ON" or "OFF" for each subfield. ..

The processing circuit 30 includes tables T1, T2 and T3. Of these, the table T1 stores the codes in the gradation control subfield corresponding to the gradation levels "0" to "1023". In the table T2, the codes in the subfields for temperature compensation are stored corresponding to the gradation levels “0” to “1023”. Further, the table T3 stores the amount of change in transmittance corresponding to the gradation level from "0" to "1023".
The processing circuit 30 converts the gradation level specified by the video data Vid-in into a subfield code for gradation control with reference to the table T1, temporarily stores the gradation level, and stores the code based on the information Sfn and Sln. It is read out, converted into a data signal Vsf, and supplied to the data line drive circuit 140.

In the present embodiment, the subfield is provided with a subfield for temperature compensation in addition to the subfield for gradation control. In the present embodiment, a code indicating that the liquid crystal element should be driven by either "ON" or "OFF" is assigned to the subfield for temperature compensation, but the code is changed according to the temperature information Tmp. To. This change will be described later.

The scanning line driving circuit 130 selects the scanning lines 112 line by line according to the control signal Yctr and the information Sln supplied from the scanning control circuit 35, supplies the H-level scanning signal to the selected scanning lines 112, and selects the scanning lines 112. An L-level scanning signal is supplied to the scanning line 112 that has not been used. In FIG. 4, the scanning signals supplied to the scanning lines 112 on the first line, the second line, the third line, ..., And the mth line are expressed as Y1, Y2, Y3, ..., Ym in this order from the top. There is.
The data line drive circuit 140 latches the data signal Vsf output from the processing circuit 30 for one line according to the control signal Xctr supplied from the scan control circuit 35, and selects the scan line 112 by the scan line drive circuit 130. Together, it is output to the data line 114. In FIG. 4, the data signals supplied to the data lines 114 in the first, second, third, ..., Nth columns in order from the left are expressed as X1, X2, X3, ..., Xn. There is.

The pixel circuit P is provided corresponding to the intersection of the scanning line 112 and the data line 114, and includes the transistor 116 and the liquid crystal element 5. The transistor 116 is, for example, an N-channel type thin film, in which the gate electrode is connected to the scanning line 112, the source electrode is connected to the data line 114, and the drain electrode is connected to the pixel electrode 118.
As described above, the pixel electrode 118 faces the common electrode 108 to which the voltage Vcom is applied, and the liquid crystal 105 is enclosed between the two electrodes. Therefore, the liquid crystal element 5 has one end as the pixel electrode 118 and the other end. Is equivalent to the capacity of sandwiching the liquid crystal 105 with the common electrode 108.

In such a configuration, in the pixel circuit P corresponding to the intersection of a certain row of scanning lines 112 and a certain row of data lines 114, when the scanning signal supplied to the scanning lines 112 reaches the H level, the said In the pixel circuit P, the transistor 116 is turned on. Therefore, in the pixel circuit P, the voltage of the data signal supplied to the data line 114 is applied to the pixel electrode 118 of the liquid crystal element 5.
When the scanning signal supplied to the scanning line 112 reaches the L level, the transistor 116 is turned off, but the liquid crystal element 5 is applied to the voltage applied to the pixel electrode 118 and the common electrode 108 when the transistor 116 is on. The voltage difference from the voltage Vcom is maintained by its capacitance.

An alignment film for aligning the molecular direction of the liquid crystal 105 in a predetermined direction is provided on each of the facing surfaces of the element substrate 100a and the opposing substrate 100b, while the absorption axis is oriented in a direction corresponding to the orientation direction on each back surface side thereof. Polarizers are provided so as to be.
In the present embodiment, when the liquid crystal element 5 is set to the normally black mode, in the pixel circuit P, if the holding voltage of the liquid crystal element 5 is zero, the transmittance becomes the minimum, while as the holding voltage increases, the transmittance becomes transparent. The rate gradually increases. Since the alignment film and the polarizer are not directly related to this case, their illustrations are omitted.
Since the liquid crystal panel 100 is a transmissive type here, it is set as the transmittance, but if it is a reflective type, the transmissivity can be read as the reflectance. Further, if a self-luminous type such as an OLED is used as the electro-optical element, it can be read as a ratio indicating brightness.

In the normally black mode, the voltage at which the relative transmittance is 10% of the voltage applied to the liquid crystal element when the transmittance in the darkest state is set to 0% and the transmittance in the brightest state is set to 100%. Is called an optical threshold voltage, and a voltage at which the relative transmittance is 90% is called an optical saturation voltage.
In the voltage modulation method, when the pixel circuit P has an intermediate gradation, the liquid crystal element 5 is designed so that a voltage equal to or higher than the optical threshold value and lower than the optical saturation voltage is applied. .. With this design, the transmittance of the pixel circuit P becomes a value reflected in the voltage applied to the liquid crystal element.

In contrast to the voltage modulation method, since the subfield drive method is used in this embodiment, the liquid crystal element 5 is driven either on, which is equal to or higher than the saturation voltage, or off, which is lower than the threshold voltage. It is composed. In this configuration, in order to express the intermediate gradation in the pixel circuit P, the liquid crystal element 5 is driven on or off in units of subfields in which the frame period is divided into a plurality of units, and the liquid crystal element 5 is driven on or off over the frame period. It is configured to control the distribution of the driving period.

FIG. 6 is a diagram showing an example of the arrangement of subfields in this embodiment. As shown in this figure, the frame period 1F is divided into four groups G1 to G4 in chronological order, and each group is further divided into five subfields. Therefore, the frame period 1F is divided into a total of 20 subfields.
Of the four groups, the first group G1 in time contains the subfields C_Sf1 and Sf1 to Sf4, and the second group G2 contains the subfields C_Sf2 and Sf5 to Sf8, and the third group. Group G3 includes subfields C_Sf3 and Sf9 to Sf12, and fourth group G4 contains subfields C_Sf4 and Sf13 to Sf16.

The period lengths of the 20 subfields are set as follows. Specifically, in the group G1, the period length of the subfield C_Sf1 is the shortest, and the periods of the subfields Sf1, Sf2, Sf3 and Sf4 are set longer in this order. Similarly, in the group G2 as well, the period length is set longer in the order of the subfields C_Sf2, Sf5, Sf6, Sf7, and Sf8. In group G3, the period length is set longer in the order of subfields C_Sf3, Sf9, Sf10, Sf11, Sf12, and in group G4, the period length is set longer in the order of subfields C_Sf4, Sf13, Sf14, Sf15, Sf16. Will be done.

In the present embodiment, 16 codes are provided to specify whether the liquid crystal element 5 is turned on or off according to the gradation level specified by the video data Vid so as to have the following characteristics. It is assigned to the subfields Sf1 to Sf16.

FIG. 7 is a diagram showing the characteristics of the transmittance of the liquid crystal element 5 with respect to the gradation level. In the figure, the horizontal axis is the gradation level. In the present embodiment, since the gradation level is 10 bits, it becomes an integer from "0" to "1023" when converted to a decimal value. In the figure, the vertical axis is the normalized transmittance.
As shown by the thick solid line, the relationship between the gradation level and the transmittance at the reference temperature (for example, 60 ° C.) has a gamma coefficient of "2.2" in consideration of human luminosity factor rather than linear characteristics. It is a characteristic of a bow. This characteristic is the target characteristic.
Whether the liquid crystal element 5 is turned on or off in each of the subfields Sf1 to Sf16 at a certain gradation level is set so as to approach the transmittance corresponding to the gradation level in the characteristics shown in FIG. .. Such a setting is executed corresponding to all 1024 gradation levels, and the codes of the subfields Sf1 to Sf16 for each of the gradation levels "0" to "1023" are, for example, table T1 (FIG. 4). (See) is stored in the processing circuit 30. The specific contents of the table will not be shown.

The transmittance with respect to the gradation level is approximately the thick solid line in FIG. 7 at the reference temperature, but changes as shown by the thin solid line when the temperature of the liquid crystal panel 100 rises from the reference temperature, and conversely from the reference temperature. When it decreases, it changes as shown by the broken line. Specifically, when the temperature of the liquid crystal panel 100 rises, the transmittance increases on the low gradation side below the gradation level A, and decreases on the high gradation side above the gradation level A. When the temperature of the liquid crystal panel 100 decreases, the transmittance decreases on the low gradation side and increases on the high gradation side.

The gradation level A differs depending on the liquid crystal panel 100, but in this description, for example, the decimal value is set to "768".
Further, the reason why the reference temperature is set to, for example, 60 ° C. is that when the liquid crystal panel 100 is used for the liquid crystal projector, when the liquid crystal projector is used, the temperature becomes relatively high because it is heated by the illumination light as compared with the environmental temperature. Because it is easy.

Here, in the first embodiment, in order to simplify the description, the configuration is such that the change in the transmittance characteristic is compensated only when the liquid crystal panel 100 drops from the reference temperature.
If the period lengths of the subfields Sf1 to Sf16 are fixed, the gradation level A does not fluctuate with respect to a temperature change as shown in FIG. Therefore, in order to compensate for the temperature, when the temperature drops from the reference temperature, the transmittance should be increased on the low gradation side below the gradation level A and decreased on the high gradation side above the gradation level A. Good.
Therefore, in the first embodiment, first, the subfields C_Sf1 to C_Sf4 are provided in addition to the subfields Sf1 to Sf16 for controlling the gradation level. Secondly, in order to increase the transmittance on the low gradation side when the temperature drops, a code for turning the liquid crystal element 5 "OFF" at the reference temperature is assigned to the subfields C_Sf1 to C_Sf4 on the high gradation side. Then, in order to reduce the transmittance, a code for turning the liquid crystal element 5 “ON” at the reference temperature is assigned to the subfields C_Sf1 to C_Sf4.
Strictly speaking, at the reference temperature, the subfields C_Sf1 to C_Sf4 are assigned the "OFF" code on the low gradation side, and the subfields C_Sf1 to C_Sf4 are assigned the "ON" code on the high gradation side. Therefore, in anticipation of this allocation, the codes of the subfields Sf1 to Sf16 are set to have the target transmittance for each gradation level.

Next, how to change the code of the subfields C_Sf1 to C_Sf4 specifically when the temperature drops will be described.

FIG. 8 shows how the transmittance of the liquid crystal element 5 changes from the gradation level “256” to “261” when the temperature of the liquid crystal panel 100 drops from the reference temperature by, for example, 5 ° C. It is a figure. The amount of change in transmittance is converted into a gradation level. For example, in the figure, the amount of change in transmittance "-10.33" at the gradation level "256" is the gradation level "245.67" in which the gradation level is lowered by "10.33" from "256". It means that the transmittance is equivalent to.
Further, in FIG. 8, the amount of change in transmittance at the gradation levels “256” to “261” is shown, but in reality, all of the gradation levels “0” to “1023” are transparent. The rate change amount is measured in advance and stored as a table T3 (see FIG. 4).
Since the gradation levels "256" to "261" are all lower than the gradation level A, the transmittance decreases when the temperature decreases. Therefore, in FIG. 8, the amount of change in transmittance is shown as a negative value. For the gradation level of the gradation level A or higher, the transmittance generally increases when the temperature decreases, so that the amount of change in the transmittance is a positive value, although not particularly shown.

The amount of change in transmittance shown in FIG. 8 generally follows the characteristics shown by the broken line in FIG. 7, but there is a difference for each gradation level. In this way, if compensation is made uniformly when there is a difference in the amount of change in transmittance for each gradation level, compensation may be over-compensated for one gradation level or insufficient compensation for another gradation level. It ends up.
Therefore, in the first embodiment, a threshold value of the amount of change in transmittance is associated with each of the subfields C_Sf1 to C_Sf4, and when the temperature of the liquid crystal panel 100 drops by 5 ° C. from the reference temperature, a certain gradation level is transmitted. When the rate change amount becomes equal to or greater than the threshold value associated with the subfields C_Sf1 to C_Sf4, the code of the subfield is changed at the gradation level.

FIG. 9 is a diagram showing an example of the threshold value of the amount of change in transmittance associated with each of the subfields C_Sf1 to C_Sf4.
In this figure, when the temperature of the liquid crystal panel 100 drops by 5 ° C from the reference temperature, the amount of change in transmittance at the gradation level lower than the gradation level A among the codes of the subfields C_Sf1 to C_Sf4 is seen as an absolute value. It indicates that the code of the subfield corresponding to the gradation level is changed from "OFF" to "ON" when the threshold value is exceeded.
In the example of FIG. 9, it is shown that the codes of the subfields C_Sf1, C_Sf3, C_Sf2, and Sf4 are changed to "ON" in this order as the amount of change in transmittance decreases by "3.5". There is.

That is, in the first embodiment, if the amount of change in transmittance at a certain gradation level is equal to or greater than the threshold value associated with the subfield C_Sf1 in terms of absolute value, the code of the subfield C_Sf1 is set to "ON". Be changed.
Further, if the amount of change in transmittance at a certain gradation level is equal to or greater than the threshold value associated with the subfield C_Sf3 in terms of absolute value, the codes of the subfields C_Sf1 and C_Sf3 are changed to "ON".
Similarly, if the amount of change in transmittance at a certain gradation level is equal to or greater than the threshold value associated with the subfield C_Sf2 in terms of absolute value, the codes of the subfields C_Sf1, C_Sf2 and C_Sf3 are changed to "ON". To.
Then, if the amount of change in transmittance at a certain gradation level is equal to or greater than the threshold value associated with the subfield C_Sf4 in terms of absolute value, the codes of the subfields C_Sf1, C_Sf2, C_Sf3 and C_Sf4 are changed to "ON". Will be done.

Specifically, the processing circuit 30 has subfields C_Sf1 to C_Sf4 for temperature compensation for the gradation levels "0" to "1023" when the temperature of the liquid crystal panel 100 drops by 5 ° C. or more from the reference temperature. Change the code of to rewrite the table T2.

FIG. 10 is a diagram showing how the codes of the subfields C_Sf1 to C_Sf4 in the gradation levels “256” to “261” change. The gradation levels "256" to "261" are all less than the gradation level A. Therefore, the codes of the subfields C_Sf1 to C_Sf4 at the reference temperature (before compensation) are all "OFF".
When the temperature of the liquid crystal panel 100 is lowered by 5 ° C. from the reference temperature, the change in transmittance of the gradation level “256” is “-10.33” as shown in FIG. 8 or FIG. The “-10.33” change in transmittance is greater than or equal to the threshold value of subfield C_Sf3 in FIG. 9 and less than the threshold value of subfield C_Sf2 in terms of absolute value. In this case, the processing circuit 30 changes the codes of the subfields C_Sf1 and C_Sf3 from "OFF" to "ON" and keeps the codes of the subfields C_Sf2 and C_Sf4 "OFF" as shown in FIG. ..

The change in transmittance of the gradation level "257" is "-14.71". The change in transmittance "-14.71" is equal to or greater than the threshold value of the subfield Sf4 in FIG. 9 in terms of absolute value. In this case, the processing circuit 30 changes all the codes of the subfields C_Sf1 to C_Sf4 from "OFF" to "ON".
Similarly, when the temperature of the liquid crystal panel 100 drops by 5 ° C. from the reference temperature, the processing circuits 30 have subfields C_Sf1 to C_Sf4 for the other gradation levels "258" to "261" in FIG. Of the codes in, the code whose transmittance change amount is equal to or greater than the threshold value is changed. Although not shown in particular, the codes of the subfields C_Sf1 to C_Sf4 are also changed for other gradation levels lower than the gradation level A.

On the other hand, for the gradation level A or higher, the codes of the subfields C_Sf1 to C_Sf4 at the reference temperature (before compensation) are all "ON". Therefore, for gradation levels of gradation level A or higher, when the temperature of the liquid crystal panel 100 drops by 5 ° C from the reference temperature, the processing circuit 30 sees the change in transmittance as an absolute value in each of the subfields C_Sf1 to C_Sf4. It is configured to determine whether or not it is above the threshold value and change the code of the subfield that is above the threshold value to "OFF".

Such an operation of changing the code in the subfields C_Sf1 to C_Sf4 for temperature compensation according to the temperature is summarized in the following flowchart.

FIG. 11 is a flowchart showing the code change operation in the subfields C_Sf1 to C_Sf4.
First, the processing circuit 30 acquires the information Tmp from the temperature detection unit 40 and grasps the temperature of the liquid crystal panel 100 (step S10).
Next, the processing circuit 30 determines whether or not the temperature of the liquid crystal panel 100 is out of the predetermined range (step S11). In the first embodiment, the term “outside the predetermined range” means a case where the temperature of the liquid crystal panel 100 drops by 5 ° C. or more from the reference temperature.
Therefore, in the processing circuit 30, the temperature of the liquid crystal panel 100 is not out of the predetermined range (if the determination result in step S11 is “No”), that is, the temperature of the liquid crystal panel 100 is not lowered by 5 ° C. or more. , The reference temperature code is used as the code in the subfields C_Sf1 to C_Sf4 (step S12).

In the first embodiment, the codes of the subfields C_Sf1 to C_Sf4 at the reference temperature are all "OFF" if they are below the gradation level A, and "ON" if they are above the gradation level A. ".
After that, the processing procedure returns to step S10 in preparation for the temperature change of the liquid crystal panel 100.

On the other hand, in the processing circuit 30, if the temperature of the liquid crystal panel 100 is out of the predetermined range (if the determination result in step S11 is “Yes”), that is, if the temperature of the liquid crystal panel 100 drops by 5 ° C. or more, From the table T3, the amount of change in transmittance corresponding to the gradation levels “0” to “1023” is read out (step S13).
Next, the processing circuit 30 compares the read transmittance change amount with the threshold value associated with the subfields C_Sf1 to C_Sf4 (step S14).
If the amount of change in transmittance at a certain gradation level is equal to or greater than the threshold value associated with the subfields C_Sf1 to C_Sf4 in absolute value, the processing circuit 30 uses the code of the subfield that is equal to or greater than the threshold value as the reference temperature. Change from the code of (step S15).

The processing circuit 30 compares the amount of change in transmittance with the threshold value associated with the subfields C_Sf1 to C_Sf4, and changes the code for all gradation levels from "0" to "1023". To do.
Further, in the subsequent subfields C_Sf1 to C_Sf4, the liquid crystal element 5 is driven on or off according to the changed code.
After that, the processing procedure returns to step S10 in preparation for the temperature change of the liquid crystal panel 100. The processing circuit 30 repeatedly executes the processing of steps S10 to S15 every predetermined period (for example, 30 seconds), so that even when the liquid crystal panel 100 drops from the reference temperature, the transmittance characteristic with respect to the gradation level is set as the target characteristic. It can be compensated to be close to.

The codes of the subfields Sf1 to Sf16 for gradation control according to the gradation level are not changed by the temperature.

In the present embodiment, the codes of the subfields C_Sf1 to C_Sf4 and Sf1 to Sf4 according to the temperature of the liquid crystal panel 100 are written as data signals in the liquid crystal element 5 of the pixel circuit P as follows.

FIG. 12 shows the temporal transition of the scanning lines selected by the scanning signals Y1 to Ym when the vertical axis is the first line to the mth line, which is the number of lines of the scanning line 112, and the elapsed time is the horizontal axis. It is a figure which shows.
When the selection of the scanning line 112 is indicated by a black dot for each scanning line, the scanning line 112 is exclusively selected line by line, so that the selected scanning lines are sequentially from the first line to the mth line with the lapse of time. Move to. Therefore, the black dots indicating the selected scanning lines are indicated by continuous points that decrease to the right with the passage of time, and are indicated by solid lines that decrease to the right for the sake of brevity in the figure.

When the scanning line 112 in the i-th row is selected in a certain subfield, the data line 114 in the j-th column is set to "ON" or "OFF" of the liquid crystal element 5 in the i-th row and j-column in the subfield. The data signal corresponding to the specified code is supplied. Therefore, in the subfield, the i-row and j-column liquid crystal elements 5 are driven on or off as specified.

FIG. 13 is a diagram showing the improvement of the transmittance characteristic with respect to the gradation level in the first embodiment. Specifically, in FIG. 13, the solid thin line is a characteristic to be targeted for a gamma coefficient of “2.2”. When the temperature of the liquid crystal panel 100 drops by 5 ° C. from the reference temperature, the broken line is the characteristic without compensation, which is the same as the broken line in FIG. 7, whereas in the present embodiment, it is shown by the thick solid line. In addition, it is possible to approach the characteristics of the target.

Even in a configuration in which the codes of the subfields Sf1 to Sf16 are changed according to the temperature change without providing the subfields C_Sf1 to C_Sf4, it is possible to maintain the transmittance characteristic with respect to the gradation level at the target characteristic. However, in such a configuration, it is necessary to define the codes of the subfields Sf1 to Sf16 corresponding to the assumed change temperature separately from the reference temperature. That is, it is very complicated because it is necessary to determine the time and effort for measuring the transmittance and what kind of code should be assigned to the subfields Sf1 to Sf16 with respect to the measured transmittance.
On the other hand, in the present embodiment, the subfields C_Sf1 to C_Sf4 for temperature compensation are provided, only the codes of the subfields C_Sf1 to C_Sf4 are changed with respect to the temperature change, and the codes of the subfields Sf1 to Sf16 are changed. Therefore, it is possible to avoid the above-mentioned troublesome complexity.

Further, it is possible to maintain the transmittance characteristic for the gradation level at the target characteristic by changing the period length of each subfield, the frame frequency, and the like according to the temperature change. However, in this configuration, it is necessary to change the clock or the like according to the temperature, which inevitably complicates the configuration. On the other hand, in the present embodiment, since the period length of each subfield, the frame frequency, and the like are not changed according to the temperature change, it is possible to avoid the complexity of the configuration as compared with the above configuration.

In the above-described first embodiment, the case where the temperature of the liquid crystal panel 100 is lowered by 5 ° C. or more from the reference temperature is a problem, but for example, the case where the temperature is lowered by half, 2.5 ° C., will be examined. Even when the temperature drops by 2.5 ° C, the amount of change in transmittance at each gradation level is measured in advance and tabulated, for example, and when the temperature of the liquid crystal panel 100 actually drops by 2.5 ° C, the temperature drops by 5 ° C. Similar to the case, it is also possible to change the code of the subfields C_Sf1 to C_Sf4 as compared with the threshold value.
However, measuring the amount of change in transmittance at each gradation level in advance over the temperature at which the liquid crystal panel 100 is expected to be used and tabulating it for each temperature only takes time and effort to measure the transmittance. It is not realistic because the configuration is complicated.
On the other hand, the amount of change in transmittance and the temperature have a substantially linear relationship.

That is, the amount of change in transmittance when the temperature of the liquid crystal panel 100 is lowered by 2.5 ° C. is estimated to be half of the amount of change in transmittance when the temperature is lowered by 5 ° C. The form will be described.

FIG. 14 shows how the codes of the subfields C_Sf1 to C_Sf4 in the gradation levels “256” to “261” change when the temperature of the liquid crystal panel 100 drops by 2.5 ° C. from the reference temperature. It is a figure which shows. As shown in FIG. 14, the amount of change in transmittance when the temperature of the liquid crystal panel 100 is lowered by 2.5 ° C from the reference temperature is the amount of change in transmittance shown in FIG. 10, that is, the amount of change in transmittance when lowered by 5 ° C. It is halved of the amount of change.
When the temperature of the liquid crystal panel 100 is lowered by 2.5 ° C. from the reference temperature, the change in transmittance of the gradation level “256” is “-5.17” as shown in FIG. The “−5.17” change in transmittance is equal to or greater than the threshold value of the subfield C_Sf1 in FIG. 9 and less than the threshold value of the subfields C_Sf2 to C_Sf4 in terms of absolute value. Therefore, when the temperature of the liquid crystal panel 100 drops by 2.5 ° C. from the reference temperature (after compensation), the processing circuit 30 displays only the code of the subfield C_Sf1 from "OFF" as shown in FIG. Change to "ON".

Similarly, for other gradation levels, when the temperature of the liquid crystal panel 100 drops by 2.5 ° C. from the reference temperature, the amount of change in transmittance among the codes of the subfields C_Sf1 to C_Sf4 is the threshold value. The above code will be changed.

According to the second embodiment, it is not necessary to measure the amount of change in transmittance for each temperature at which the liquid crystal panel 100 is expected to be used and for each gradation level.

In the second embodiment, it is assumed that the temperature of the liquid crystal panel 100 is lowered by 2.5 ° C., but it may be assumed that the temperature of the liquid crystal panel 100 is lowered by, for example, 7.5 ° C., 10 ° C., or 12.5 ° C. When the temperature of the liquid crystal panel 100 is lowered by 7.5 ° C., 10 ° C., 12.5 ° C., the amount of change in transmittance is 1.5 times, 2 times, and the amount of change in transmittance when the temperature is lowered by 5 ° C., respectively. 5 times.
Specifically, in the processing circuit 30, the difference between the temperature indicated by the information Tmp and the reference temperature with respect to the difference between the reference temperature and the temperature at which the amount of change in transmittance is measured (the temperature lowered by 5 ° C from the reference temperature). Is corrected by multiplying the amount of change in transmittance with respect to, and the magnitude relationship between the corrected amount of change in transmittance and the threshold value associated with the subfields C_Sf1 to C_Sf4 is determined, and according to the determination result. The codes of the subfields C_Sf1 to C_Sf4 may be changed.

In the first and second embodiments described above, in the first and second embodiments, compensation is provided only when the temperature of the liquid crystal panel 100 is lower than the reference temperature.
Not limited to this case, compensation is possible even when the temperature of the liquid crystal panel 100 rises above the reference temperature.
Specifically, when the temperature of the liquid crystal panel 100 rises above the reference temperature, the transmittance characteristic becomes the characteristic shown by a thin solid line in FIG. 7. Therefore, the codes of the subfields C_Sf1 to C_Sf4 are simply changed to "OFF" according to the amount of change in transmittance on the low gradation side and to "ON" according to the amount of change in transmittance on the high gradation side. Any configuration may be used.
However, in such a configuration, in preparation for a temperature rise when the liquid crystal panel 100 is at the reference temperature, a part or all of the codes of the subfields C_Sf1 to C_Sf4 are set to "ON" on the low gradation side, and the actual It is necessary to change the code of the "ON" to "OFF" when the temperature rises to. In such a setting, even if the gradation level is the lowest "0", the code of the subfields C_Sf1 to C_Sf4 is "ON" in some cases, so that the transmittance of the liquid crystal element 5 increases. As a result of so-called black floating, the contrast is lowered.
Therefore, a third embodiment that can compensate even when the temperature of the liquid crystal panel 100 rises while suppressing the decrease in contrast will be described.

In the third embodiment, first, the gradation level B is provided on the lower gradation side than the gradation level A, and at the reference temperature, the gradation level on the lower gradation side than the gradation level B is sub. Set all the codes of fields C_Sf1 to C_Sf4 to "OFF". The gradation level B is, for example, a decimal value of "64".
Second, at the reference temperature, for the gradation level above the gradation level B and below the gradation level A, the codes of the subfields C_Sf1 and C_Sf3 are set to "OFF", and the codes of the subfields C_Sf2 and C_Sf4 are set to "ON". , And set each.
Third, at the reference temperature, the codes of the subfields C_Sf1 and C_Sf3 are set to "ON" and the codes of the subfields C_Sf2 and C_Sf4 are set to "OFF" for the gradation level of the gradation level A or higher.
Fourth, the threshold value of the amount of change in transmittance associated with each of the subfields C_Sf1 to C_Sf4 is set as shown in FIG. 15, for example.
In the third embodiment, since the case where the temperature of the liquid crystal panel 100 not only decreases from the reference temperature but also increases is dealt with, the threshold value is a low temperature threshold value and a high temperature threshold value. And are prepared. Specifically, in principle, when the temperature of the liquid crystal panel 100 drops from the reference temperature, it is dealt with by inverting the codes of the subfields C_Sf1 and C_Sf3, and when it rises from the reference temperature, the subfield C_Sf2 And C_Sf4 code is reversed to deal with it.

In the third embodiment, when the designated gradation level is equal to or higher than the gradation level B and lower than the gradation level A, and the temperature of the liquid crystal panel 100 drops by 5 ° C. from the reference temperature, the floor concerned. If the amount of change in transmittance at the key level is equal to or greater than the threshold value associated with subfield C_Sf1 in terms of absolute value, the code of subfield C_Sf1 is changed to "ON" and associated with subfield C_Sf3. If it is equal to or higher than the threshold value, the codes of the subfields C_Sf1 and C_Sf3 are changed to "ON".
Further, in this case, when the temperature of the liquid crystal panel 100 rises by 5 ° C. from the reference temperature, the amount of change in transmittance at the gradation level is equal to or greater than the threshold value associated with the subfield C_Sf2 in terms of absolute value. For example, the code of the subfield C_Sf2 is changed to "OFF", and if it is equal to or higher than the threshold value associated with the subfield C_Sf4, the codes of the subfields C_Sf2 and C_Sf4 are changed to "OFF".

FIG. 15 is a diagram showing how the codes of the subfields C_Sf1 to C_Sf4 change when the temperature of the liquid crystal panel 100 is lowered by 5 ° C. from the reference temperature and when the temperature is raised by 5 ° C.
In FIG. 15, the gradation levels "61" to "63" are illustrated as less than the gradation level B, and the gradation level "256" is defined as being equal to or higher than the gradation level B and less than the gradation level A. Up to "261" is illustrated.

In the third embodiment, at the reference temperature (before compensation), the subfields C_Sf1 to C_Sf4 are all "OFF" for the gradation level on the gradation level lower than the gradation level B, so that the temperature rises. In that case, it is not possible to compensate in the direction of lowering the transmittance.
Specifically, in FIG. 15, at the gradation level “61”, the amount of change in transmittance on the high temperature side is “2.53”, and this value is the high temperature side of the subfield C_Sf2 in FIG. 16 in terms of absolute value. It is equal to or higher than the threshold value of "+2.5". Since the code of the subfield C_Sf2 of the reference temperature (before compensation) is "OFF" at the gradation level "61", according to the principle, the code of the subfield C_Sf2 at the gradation level "61" is "OFF". Should be changed to "ON".
However, if the code of the subfield C_Sf2 at the gradation level "61" is changed from "OFF" to "ON", the compensation is in the direction of increasing the transmittance, which does not match the purpose.
Therefore, in the third embodiment, the transmittance is exceptionally not compensated when the temperature rises on the gradation side lower than the gradation level B.

In FIG. 15, at the gradation level “62”, the amount of change in transmittance on the low temperature side is “-7.333”, and this value is the threshold value on the low temperature side of the subfield C_Sf1 in FIG. 16 in terms of absolute value. The value is "-7.0" or more. Therefore, when the temperature of the liquid crystal panel 100 drops by 5 ° C. from the reference temperature, the code of the subfield C_Sf1 at the gradation level "62" is changed from "OFF" to "ON".

Further, in the gradation level in the range of the gradation level B or higher and lower than the gradation level A, when the temperature of the liquid crystal panel 100 changes from the reference temperature, the codes of the subfields C_Sf1 to C_Sf4 are changed as described above. To.

For example, at the gradation level "256" in the range, the amount of change in transmittance is "-10.33" on the low temperature side, and the absolute value is "-7.0", which is the low temperature side threshold value in the subfield C_Sf1. It is less than "-14.0" of the low temperature side threshold value in the subfield C_Sf3. Therefore, when the temperature of the liquid crystal panel 100 drops by 5 ° C. from the reference temperature, the code of the subfield C_Sf1 is changed to "ON", and the code of the subfield C_Sf3 is maintained at "OFF". In this case, the codes of the subfields C_Sf2 and C_Sf4 are not subject to change, and are therefore maintained at "ON".

Further, at the gradation level "256", the amount of change in transmittance is "+4.68" on the high temperature side, which is equal to or higher than the low temperature side threshold value "+2.5" in the subfield C_Sf2 in terms of absolute value. , It is less than "+5.0" of the high temperature side threshold value in the subfield C_Sf4. Therefore, when the temperature of the liquid crystal panel 100 rises by 5 ° C. from the reference temperature, the code of the subfield C_Sf2 is changed to "OFF", and the code of the subfield C_Sf4 is maintained at "ON". In this case, the codes of the subfields C_Sf1 and C_Sf3 are not subject to change, and are therefore maintained at "OFF".

Regarding the gradation level of the gradation level A or higher, it is necessary to decrease the transmittance when the temperature of the liquid crystal panel 100 decreases and increase the transmittance when the temperature of the liquid crystal panel 100 increases.
Therefore, although the gradation level is not particularly shown, when the temperature of the liquid crystal panel 100 drops by 5 ° C., the code of the subfields C_Sf1 and / and C_Sf3 is set to "OFF" according to the amount of change in transmittance. When the temperature is changed and the temperature rises by 5 ° C., the code of the subfields C_Sf2 and / and C_Sf4 is changed to "ON" according to the amount of change in transmittance.

Further, in the third embodiment, as in the second embodiment, the amount of change in transmittance may be corrected by multiplying the amount of change in transmittance by the ratio of the detected temperature.

As described above, according to the third embodiment, it is possible to compensate not only when the temperature of the liquid crystal panel 100 decreases but also when the temperature increases while suppressing the decrease in contrast.

In each of the above-described embodiments, the liquid crystal element 5 has been described as the normally black mode. However, if the holding voltage of the liquid crystal element 5 is zero, the transmittance becomes maximum, while as the holding voltage increases, the transmittance becomes transparent. It can also be applied to the normally white mode in which the rate gradually decreases.
In each embodiment, when the temperature of the liquid crystal panel 100 changes, the table T2 is rewritten in the processing circuit 30 to change the codes of the subfields C_Sf1 to C_Sf4 for temperature compensation. A plurality of tables for storing the codes of the subfields C_Sf1 to C_Sf4 of the above may be prepared, and one table corresponding to the temperature information Tmp may be selected.

The period length, order, and number of the temperature compensation subfield and the gradation control subfield may be other than those shown in FIG.
For example, the number of subfields for temperature compensation is not limited to "4", and may be "2" or more. Further, the period lengths of the temperature compensation subfields do not have to be the same and may be different from each other. As the period length of the subfield for temperature compensation, a plurality of two types, short and long, may be provided.
The selection order of the scanning lines 112 is not limited to the order shown in FIG. 12, and a plurality of lines may be skipped and selected to express different subfield periods in the liquid crystal element 5 of each line.
Further, the present disclosure can be expressed not only as an electro-optical device but also as a driving method of the electro-optic device.

In each of the above-described embodiments, the liquid crystal element 5 is an example of an electro-optical element. The reference temperature is an example of the first temperature, a temperature 5 ° C. lower or higher than the reference temperature is an example of the second temperature, and the amount of change in transmittance is an example of the amount of gradation change. In the first embodiment, the gradation level A is an example of a predetermined level, in the third embodiment, the gradation level B is an example of the first level, and the gradation level A is an example of the second level.
Further, in each embodiment, the subfield C_Sf1 is an example of the first compensation subfield, the subfield C_Sf2 is an example of the second compensation subfield, the subfield C_Sf3 is an example of the third compensation subfield, and the subfield. C_Sf4 is an example of the fourth compensation subfield.

Next, an example of an electronic device using the above-mentioned electro-optical device 1 will be described.
FIG. 17 is a diagram showing a configuration of a three-panel liquid crystal projector using the liquid crystal panel 100 of the electro-optical device 1 as a light bulb. As shown in FIG. 17, the liquid crystal projector 2100 includes liquid crystal panels 100R, 100G and 100B. The liquid crystal panels 100R, 100G, and 100B are the same as the liquid crystal panel 100 in the embodiment and the like, and transmit transmission images based on the video data corresponding to each color of R, G, and B supplied from the host device (not shown), respectively. Generate.

Inside the liquid crystal projector 2100, a lamp unit 2102 made of a white light source such as a halogen lamp is provided. The projected light emitted from the lamp unit 2102 is separated into three primary colors of red, green, and blue by three mirrors 2106 and two dichroic mirrors 2108 arranged inside. Of these, red light is incident on the liquid crystal panel 100R, green light is incident on the liquid crystal panel 100G, and blue light is incident on the liquid crystal panel 100B.
The blue optical path is longer than other red and green. Therefore, the blue light is guided to the liquid crystal panel 100B via the relay lens system 2121 including the incident lens 2122, the relay lens 2123, and the outgoing lens 2124 in order to prevent loss in the optical path.

In the liquid crystal panel 100R, the data signal of the red component is written for each pixel circuit P by the scanning line driving circuit 130 and the data line driving circuit 140. When a data signal is written to the pixel circuit P in the liquid crystal panel 100R, the transmittance is set according to the data signal. Therefore, in the liquid crystal panel 100R, the transmittance of the incident red light is controlled for each pixel, so that a transmitted image of the red component in the image to be displayed is generated.
Similarly, in the liquid crystal panels 100G and 100B, the data signal of the green component and the data signal of the blue component are written for each pixel by the drive circuit, and among the images to be displayed, the transmitted images of the green and blue components are displayed. Will be generated.

The transmitted images of each color generated by the liquid crystal panels 100R, 100G, and 100B are incident on the dichroic prism 2112 from three directions. Then, in this dichroic prism 2112, the light of R and B is refracted at 90 degrees, while the light of G travels straight. Therefore, after the images of each color are combined, the color image is projected on the screen 2120 by the projection lens 2114.
The transmitted images of the liquid crystal panels 100R and 100B are projected after being reflected by the dichroic prism 2112, whereas the transmitted images of the liquid crystal panel 100G are projected in a straight line. Therefore, the transmitted images of the liquid crystal panels 100R and 100B are horizontally inverted with respect to the transmitted images of the liquid crystal panel 100G.

1 ... Electro-optical device, 3 ... Display control circuit, 5 ... Liquid crystal, 30 ... Processing circuit, 35 ... Scan control circuit, 100 ... Liquid crystal panel, 100a ... Element substrate, 100b ... Opposite substrate, 108 ... Common electrode, 118 ... Pixel Electrodes, 130 ... scanning line drive circuit, 140 ... data line drive circuit.

Claims (11)

An electro-optical element provided corresponding to a scanning line and a data line and driven according to a data signal corresponding to on or off when the scanning line is selected has a brightness corresponding to a specified gradation level. It is a driving method of an electro-optic device that is controlled so as to be
The frame period is divided into a plurality of subfields, two or more of the plurality of subfields are used for temperature compensation, and the other two or more are used for gradation control.
The electro-optical element is turned on or off according to the gradation level in each of the gradation control subfields.
At the first temperature, the electro-optic element is turned on or off for each gradation level in each of the temperature compensation subfields.
Whether or not the gradation change amount for each gradation level is equal to or greater than the threshold value associated with each of the temperature compensation subfields when the temperature changes to a second temperature different from the first temperature. A method for driving an electro-optic device, which determines whether or not the temperature is on or off in a subfield corresponding to a gradation level equal to or higher than the threshold value from on or off of the first temperature. When the gradation level is less than a predetermined level at the first temperature, the electro-optic element is turned off in all of the temperature compensation subfields.
The method for driving an electro-optical device according to claim 1. Based on the difference between the detected temperature and the first temperature, the gradation change amount measured for each gradation level is corrected, and the corrected gradation change amount is compared with the threshold value.
The method for driving an electro-optic device according to claim 1 or 2. The ratio of the difference between the detected temperature and the first temperature to the difference between the first temperature and the second temperature is corrected by multiplying the gradation change amount, and the corrected gradation change amount is corrected. Compare with the threshold,
The method for driving an electro-optical device according to claim 3. The subfield for temperature compensation is
Includes the first compensation subfield, the second compensation subfield, the third compensation subfield and the fourth compensation subfield.
A first threshold value is associated with the first compensation subfield, and the first threshold value is associated with the first compensation subfield.
A second threshold is associated with the second compensation subfield.
A third threshold value is associated with the third compensation subfield, and the third threshold value is associated with the third compensation subfield.
A fourth threshold is associated with the fourth compensation subfield.
The method for driving an electro-optical device according to any one of claims 1 to 4. The first threshold value, the third threshold value, the second threshold value, and the fourth threshold value are
Looking at the absolute value,
The relationship is such that the first threshold value <the third threshold value <the second threshold value <the fourth threshold value.
When the temperature drops from the first temperature,
If the amount of gradation change at the specified gradation level is equal to or greater than the first threshold value in terms of absolute value, the electro-optical element is turned on in the first compensation subfield.
If the amount of gradation change is equal to or greater than the third threshold value in terms of absolute value, the electro-optical element is turned on in the first compensation subfield and the third compensation subfield.
If the amount of gradation change is equal to or greater than the second threshold value in terms of absolute value, the electro-optic element is turned on in the first compensation subfield, the second compensation subfield, and the third compensation subfield. Let me
If the amount of gradation change is equal to or greater than the fourth threshold value in terms of absolute value, the electro-optic element is referred to as the first compensation subfield, the second compensation subfield, the third compensation subfield, and the fourth compensation subfield. Turn on in the compensation subfield,
The method for driving an electro-optical device according to claim 5. The first threshold value, the third threshold value, the second threshold value, and the fourth threshold value are
Looking at the absolute value,
The first threshold <the third threshold,
And
The relationship is such that the second threshold value <the fourth threshold value.
When the specified gradation level is equal to or higher than the first level and lower than the second level,
When the temperature drops from the first temperature,
If the amount of gradation change at the gradation level is equal to or greater than the first threshold value in terms of absolute value, the electro-optical element is turned on in the first compensation subfield.
If the amount of gradation change is equal to or greater than the third threshold value in terms of absolute value, the electro-optical element is turned on in the first compensation subfield and the third compensation subfield.
When the temperature rises from the first temperature,
If the amount of gradation change is equal to or greater than the second threshold value in terms of absolute value, the electro-optical element is turned off in the second compensation subfield.
If the amount of gradation change is equal to or greater than the fourth threshold value in terms of absolute value, the electro-optical element is turned off in the second compensation subfield and the fourth compensation subfield.
The method for driving an electro-optical device according to claim 1. When the gradation level is less than the first level at the first temperature, the electro-optic element is turned off in all of the temperature compensation subfields.
The method for driving an electro-optical device according to claim 7. The duration of the plurality of subfields is constant with respect to temperature changes.
The method for driving an electro-optical device according to any one of claims 1 to 8. An electro-optical element provided corresponding to a scanning line and a data line and driven according to a data signal corresponding to on or off when the scanning line is selected has a brightness corresponding to a specified gradation level. It is an electro-optical device that controls so that
A temperature detector that detects the temperature and
The frame period is divided into a plurality of subfields, two or more of the plurality of subfields are used for temperature compensation, and the other two or more are used for gradation control.
The electro-optical element is turned on or off according to the gradation level in each of the gradation control subfields.
A display control circuit that turns on or off the electro-optical element for each gradation level in each of the subfields for temperature compensation when the temperature detected by the temperature detection unit is the first temperature.
Including
The display control circuit
When the temperature detected by the temperature detection unit changes to a second temperature different from the first temperature,
It is determined whether or not the gradation change amount for each gradation level is equal to or more than the threshold value associated with each of the temperature compensation subfields, and the gradation level corresponding to the threshold value or more is supported. An electro-optic device that changes on or off in a subfield that has been turned on or off from the on or off of the first temperature. An electronic device having the electro-optical device of claim 10.

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