JP2010107581A - Driving method and electro-optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving method and electro-optical device, taking into consideration a delay in optical response, while adequately ensuring brightness of a picture in color sequential drive system. <P>SOLUTION: Each of the pixels of a display panel has transmissivity corresponding to a written voltage. LEDs emit R (red), G (green), and B (blue) light beams to the display panel in order. A frame period is divided into R-G-B sub-frame periods. Each sub-frame period has first and second scanning periods. Of the two pixels adjacent to each other in a vertical direction in the first scanning period, a data signal corresponding to a slower optical response pixel is written to the pixel of the display panel, thereby forming a low resolution image. Then, in the second scanning period, an image of resolution higher than that in the first scanning period is formed. After the end the first scanning period and after the lapse of a standby period, the LEDs are caused to emit light. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a driving technique for a so-called color sequential electro-optical device.

  In general, in the color sequential method, a frame period for forming one color image is divided into subframe periods corresponding to, for example, three primary colors of red (R), green (G), and blue (B), and each sub In the frame period, information (for example, voltage) corresponding to the gradation (brightness) of the primary color component in the subframe period is written in the pixel of the display panel, and then the display panel is irradiated with light of the primary color. Yes. As a result, the primary color images of R, G, and B are sequentially displayed, so that these primary color images are overlapped and viewed as a full color image by humans (see Patent Document 1). In such a color sequential method, it is not necessary to provide a color filter in the display element, and it is not necessary to divide one pixel into R, G, and B sub-pixels, which facilitates high definition.

In such a color sequential method, after writing information (for example, voltage) corresponding to the brightness of the primary color component to all pixels in each sub-frame, the irradiation of the primary color light is started on a plurality of pixels. Since there is a possibility that brightness cannot be sufficiently obtained, a method of starting light irradiation before writing to all pixels has been devised (see Patent Document 2).
JP-A-11-237606 JP 2003-107425 A

However, this method is effective in ensuring the brightness of the screen, but if the optical response characteristics of the pixels of the display panel are poor, light irradiation is started with an insufficient response to the written voltage. Therefore, it was pointed out that an image different from the written content would be visually recognized.
The present invention has been made in view of the above-described circumstances, and one of its purposes is that in a color sequential method, an image different from the written content is visually recognized after sufficiently ensuring the brightness of the screen. It is to provide a technique that avoids this.

  In order to solve the above-described problem, a driving method of an electro-optical device according to the invention includes a plurality of pixels each having a transmittance or a reflectance according to written information, and the plurality of pixels. Irradiating means for sequentially irradiating light of at least three different primary colors, and dividing a unit period into subframe periods corresponding to the primary colors, and performing a first scan on the plurality of pixels in each subframe period And the second scan following the first scan, the primary color component information corresponding to the subframe period is written, and the same information is written to two or more adjacent pixels in the first scan, An image having a resolution lower than the resolution defined by a plurality of pixels is formed, and information to be written to the two or more pixels in the first scan is set to one of the two or more pixels. Information is determined based on image information of the two or more pixels, and an image having a resolution higher than the low resolution is formed by the second scan, and after the first scan, a next subframe period Before the first scanning in the above, the irradiating means irradiates the pixels with the primary color light. According to the present invention, a low-resolution image is formed by simultaneously writing the same image information to two or more pixels. The image information to be written is selected from the image information corresponding to the two or more pixels. This is determined based on image information of two or more pixels. Pixels that are likely to be delayed in optical response can be written first from the image information, and it is possible to avoid viewing an image different from the written content.

In the present invention, each of the plurality of pixels includes a liquid crystal element, and the response time when the transmittance or reflectance of the liquid crystal element is changed from the increasing side to the decreasing side is increased from the decreasing side to the increasing side. If the response time is shorter than the change time, the information written to the two or more pixels in the first scan is the image information of the brightest pixel among the image information of the two or more pixels. In this case, it is preferable that the information to be written in the two or more pixels is determined as the image information of the darkest pixel among the image information of the two or more pixels. In the present invention, it is also preferable that information on pixels that are not written in the two or more pixels in the first scan is written in corresponding pixels in the second scan.
In the present invention, the plurality of pixels are arranged corresponding to intersections of a plurality of rows of scanning lines and a plurality of columns of data lines, and data supplied to the data lines when the scanning lines are selected. The signal voltage is written, and in the first scan, the odd-numbered scanning lines and the even-numbered scanning lines adjacent to the odd-numbered scanning lines are paired and sequentially selected in a predetermined direction. When a pair of odd-numbered and even-numbered scanning lines are selected simultaneously, the brightness information of two pixels corresponding to the intersection of the two scanning lines and one data line is compared, Any brightness information may be determined as a representative value, and a voltage data signal based on the brightness information determined as the representative value may be supplied to the one data line.
Here, in the present invention, each of the plurality of pixels includes a liquid crystal element, and the response time when the transmittance or reflectance of the liquid crystal element is changed from the increasing side to the decreasing side is increased from the decreasing side. If the response time is shorter than the response time when changing to the other side, in the first scan, the brightness information of the brighter one of the brightness information of the two pixels is determined as a representative value, and in the opposite case In the first scan, it is preferable to determine darkness brightness information among the brightness information of the two pixels as a representative value.
In the present invention, information on a pixel that is not determined as a representative value among the two pixels in the first scan may be written in a corresponding pixel in the second scan. The present invention can be conceptualized not only as a driving method but also as an electro-optical device.

  Hereinafter, modes for carrying out the present invention will be described.

<First Embodiment>
First, the driving method of the electro-optical device according to the first embodiment of the invention will be described. FIG. 1 is a diagram showing an optical configuration of a projector as an example of an electro-optical device to which this driving method is applied.
In this figure, an LED 11R is a light emitting diode that is positioned in the 12 o'clock direction as viewed from the center of the dichroic prism 13 and emits R (red) light downward in the figure. The R light emitted by the LED 11R becomes a substantially parallel light beam by the collimator lens 12R. Similarly, the LEDs 11G and 11B are light emitting diodes that are positioned in the 9 o'clock and 6 o'clock directions, respectively, and emit G (green) and B (blue) light toward the right and upward in the drawing. The G and B lights emitted by the LEDs 11G and 11B are also converted into substantially parallel light beams by the collimator lenses 12G and 12B, respectively.
Note that the LEDs 11R, 11G, and 11B are controlled to emit light in order by a control circuit that will be described later, so that these three LEDs serve as irradiation means.

  The dichroic prism 13 has dichroic surfaces 13R and 13B orthogonal to each other. Of these, the dichroic surface 13R reflects R light incident from the 12 o'clock direction, emits it in the 3 o'clock direction, and transmits light of other colors. The dichroic surface 13B reflects B light incident from the 6 o'clock direction, emits it in the 3 o'clock direction, and transmits light of other colors. On the other hand, the G light incident from the 9 o'clock direction passes through the dichroic surfaces 13R and 13B and is emitted as it is in the 3 o'clock direction.

A display panel 100 is disposed on the exit surface of the dichroic prism 13. In this embodiment, the display panel 100 is, for example, an active matrix transmissive liquid crystal display panel, and includes a plurality of pixels. The projection lens group 14 is an optical system that enlarges and projects a transmission image whose transmittance is defined for each pixel by the display panel 100 onto the screen 200.
As will be described later, the frame period is divided into R, G, and B subframe periods, and in each subframe period, a voltage that gives the brightness of the primary color components of R, G, and B is written to each pixel. The operation of causing the primary color LED to emit light is repeated R, G, and B. For this reason, R, G, and B primary color images are sequentially displayed, and these primary color images are overlapped and visually viewed as a full color image.

Next, the electrical configuration of the projector 10 will be described with reference to FIG.
As shown in this figure, the projector 10 includes a control circuit 20, an image processing circuit 30, a data signal conversion circuit 40, and a display panel 100. Among these, the control circuit 20 controls each unit based on a synchronization signal Sync supplied from a host device (not shown).
The image processing circuit 30 temporarily stores the digital video signal Vid supplied from the host device in the internal memory, and then reads out the primary color component of the pixel according to the control by the control circuit 20 and outputs it as the video signal Vd.
Here, the video signal Vid supplied from the host device is digital data that designates the brightness (gradation) of each color component of R, G, and B for each pixel of the display panel 100, and is included in the synchronization signal Sync. Are supplied in the order of pixels to be scanned in accordance with a vertical scanning signal, a horizontal scanning signal, and a dot clock signal (not shown). However, the video signal Vd read out and output in the image processing circuit 30 is not related to the order of the pixels supplied from the host device, but relates to a specific row or a specific pixel as will be described later. It is.

  The data signal conversion circuit 40 converts the video signal Vd supplied from the image processing circuit 30 into an analog data signal Vs suitable for driving the display panel 100, and matches the drive timing of the Y driver 130 and the X driver 140. To the display panel 100.

In the display region 100a of the display panel 100, for example, 768 rows of scanning lines 112 extend in the horizontal direction in the figure, and 1024 columns of data lines 114 extend in the vertical direction in the figure, and each scanning line 112 The pixels 110 are disposed so as to be electrically insulated from each other and corresponding to the intersections of the scanning lines 112 and the data lines 114, respectively. Therefore, in the present embodiment, the pixels 110 are arranged in a matrix of 768 rows × 1024 columns in the display region 100a.
In order to distinguish the scanning lines 112 for convenience, in the following description, there are cases in which the first, second, third,. Similarly, in order to distinguish the data lines 114, they may be referred to as 1, 2, 3,.

The Y driver 130 is a scanning line driving circuit that supplies a scanning signal to each scanning line under the control of the control circuit 20, and selects a selected voltage for the selected scanning line and a non-selected voltage for the other scanning lines. , Respectively. Note that the scanning signals supplied to the scanning lines 112 in the first, second, third,..., And 768th rows are denoted as G1, G2, G3,.
The X driver 140 is a data line driving circuit that samples the data signal Vs converted by the data signal conversion circuit 40 on each of the pixels 110 corresponding to the selected row. Note that the data signals sampled on the data lines 114 in the 1, 2, 3,..., 1024th column are denoted by d1, d2, d3,.

The pixel 110 will be described with reference to FIG.
As shown in this figure, in the pixel 110, the source electrode of the n-channel TFT 116 is connected to the data line 114, the drain electrode is connected to the pixel electrode 118, and the gate electrode is connected to the scanning line 112. It is connected.
The pixel electrode 118 is provided for each pixel, whereas the counter electrode 108 is provided in common to all the pixels so as to face all of the pixel electrodes 118, and a constant voltage LCcom is applied thereto. . Then, the liquid crystal 105 is sandwiched between the counter electrode 108 and the pixel electrode 118, thereby forming the liquid crystal element 120. Therefore, the liquid crystal element 120 including the pixel electrode 118, the counter electrode 108, and the liquid crystal 105 is provided for each pixel.

The liquid crystal element 120 having such a configuration holds a voltage between the pixel electrode 118 and the counter electrode 108, and has a transmittance corresponding to the effective value of the held voltage if it is a transmission type. This is because in the liquid crystal element 120, the molecular orientation state of the liquid crystal 105 interposed between the two electrodes changes due to fear of voltage between the pixel electrode 118 and the counter electrode 108.
When a selection voltage is applied to the scanning line 112 and a data signal having a voltage corresponding to the designated gradation value is supplied to the pixel corresponding to the selected scanning line 112 to the data line 114, the pixel in the selection scanning line is supplied. 110 TFT 116 is turned on, and the data signal is applied to the pixel electrode 118 via the TFT 116 in the on state. Therefore, a voltage corresponding to the gradation value is applied to and held in the liquid crystal element 120, The transmittance according to the gradation can be made.
Note that even when a non-selection voltage is applied to the scan line to turn off the TFT 116, the voltage written in the liquid crystal element 120 when the TFT 116 is on is held by its capacitance.

In the present embodiment, for convenience, if the effective voltage value held in the liquid crystal element 120 is close to zero, the light transmittance is maximized to display white, while the amount of transmitted light increases as the effective voltage value increases. It is assumed that the normally white mode decreases.
In order to prevent the direct current component from being applied to the liquid crystal 105, the data signal conversion circuit 40 converts the video signal Vd specifying the brightness of the pixel into the data signal Vs to be applied to the pixel electrode 118. The reference voltage Vc (substantially the same voltage as the voltage LCcom of the counter electrode 108 or a lower voltage) is set to a predetermined period (for example, a subframe period, which will be described later), between a higher positive voltage and a lower negative voltage. Alternatively, conversion is performed by alternately switching every frame period). This polarity is specified by the control circuit 20.

FIG. 4 is a diagram showing the characteristics of optical response (transmittance) with respect to elapsed time when there is a voltage change in the liquid crystal element 120.
In the normally white mode, when the light state is set (when the transmittance of the liquid crystal element 120 is increased), the effective value of the held voltage may be reduced, and on the contrary, the pixel 110 is set in the dark state. In the case of reducing the transmittance of the liquid crystal element 120, the effective value of the held voltage may be increased. At this time, as shown in FIG. 4, the response time for the voltage change changes from the dark state to the bright state by lowering the applied voltage than when the applied voltage is increased to change from the bright state to the dark state. The case is longer than that.
This means that when the pixel 110 is set to the bright state, it takes time to obtain the transmittance corresponding to the written voltage, compared to the case where the pixel 110 is set to the dark state.
For this reason, in color sequential driving according to the present embodiment, roughly speaking, when forming a low resolution image, pixels in a bright state are preferentially written, and then high-resolution writing is started. After a certain period of time has elapsed after writing for the low resolution image, the light emission of the LED is started.

Hereinafter, details of the color sequential driving according to the present embodiment will be described. FIG. 5 is a diagram showing an outline of color sequential driving according to the present embodiment.
In this figure, the frame period refers to a period required to display one frame of a color image by driving the display panel 100 or the LEDs 11R, 11G, and 11B. If the vertical scanning frequency is 60 Hz, The reciprocal is 16.7 milliseconds. The vertical scanning period and the frame period defined by the synchronization signal Sync are the same in terms of the period length, but the video signal Vid supplied in synchronization with the synchronization signal Vsync is temporarily stored in the image processing circuit 30. In addition, since the display panel 100 and the like are driven in accordance with the readout, the frame period is delayed from the vertical scanning period in terms of timing.

  As shown in FIG. 5, the frame period is equally divided into three sub-frame periods of R, G, and B, and each of the R, G, and B sub-frame periods is divided into a first scanning period and a second scanning period. Divided into periods. In addition, after the first scanning period ends, the LED of the color corresponding to the subframe starts to emit light after a standby period.

First, in the first scanning period (R first scanning period) of the R subframe, data signals corresponding to the gray level of the R component are written into the display panel 100 in units of two rows. Specifically, in the R first scanning period, the control circuit 20 sets odd-numbered i (i is 1, 3, 5,..., 767) rows for the Y driver 130 and 1 for the odd-numbered i rows. The scanning signals G1, G2, G3,..., G768 are shown in FIG. 6 by controlling so that the selection voltage is simultaneously applied to the two rows of the even (i + 1) row below the row in order from the top. On the other hand, the X driver 140 is controlled so that the data signal Vs is sampled in order on the data lines 114 of 1, 2, 3,.
In accordance with the output of the scanning signal, for example, when the selection voltage is simultaneously applied to the odd-numbered i-th row and the even-numbered (i + 1) -th row, the control circuit 20 stores the image processing circuit 30 in the internal memory. Of the stored video signals, the gray levels of the R components designated by the two pixels located in the same column in the i-th row and the (i + 1) -th row are compared, and the brighter one is assigned 1, 2, 3... 1024 columns are controlled to be read out in order, and the polarity is designated for the data signal conversion circuit 40.

With this control, in the first scanning period of R, when viewed in the same column of the display panel 100, two pixels of the odd row and the even row adjacent to the odd row correspond to the pixels of the bright gradation. Data signals written simultaneously. Therefore, each pixel 110 is written with a voltage corresponding to the gradation of the R component, which is an image in which the resolution in the vertical direction is reduced to half.
In the R first scanning period, two rows of scanning lines are simultaneously selected, so the time required for the R first scanning period is halved compared to the case of selecting one row at a time.

Next, in the second scanning period (R second scanning period) of the R subframe, a data signal corresponding to the gradation of the R component is sequentially written in each pixel 110 of the display panel 100. More specifically, in the R second scanning period, the control circuit 20 controls the Y driver 130 to apply the selection voltage to the scanning lines one row at a time from the top, so that the scanning signals G1, G2 are applied. , G3,..., G768 are output as shown in FIG. 7, while the X driver 140 sends the data signal Vs to the data lines 114 of 1, 2, 3,. Control to sample.
In accordance with the output of the scanning signal, for example, when a selection voltage is applied to a scanning line in a certain row, the control circuit 20 sends the image processing circuit 30 out of the video signals stored in the internal memory. In the row, control is performed so that the gradations of the R component corresponding to the pixels of 1, 2, 3,..., 1024 columns are read in order, and the polarity is designated to the data signal conversion circuit 40.

  With this control, the voltage of the data signal corresponding to the gradation of the R component is written in each pixel 110 in the R second scanning period. Note that the voltage of the data signal corresponding to the same gradation is written again in the R second scanning period for the pixels that are written in the R first scanning period.

On the other hand, when the R standby period has elapsed after the end of the first R scanning period, the control circuit 20 starts the light emission of the LED 11R and continues the light emission for the R light emission period.
In the R first scanning period, a light state pixel having a slow optical response is preferentially written, and the same signal is written again in the R second scanning period, so that the pixel is written in the R light emitting period. It is considered that the transmittance corresponds to the voltage. Further, although the pixels in the dark state are written in the R second scanning period later than the pixels in the bright state, since the optical response is fast, the transmission corresponding to the written voltage is at least until the end of the R emission period. It is thought that it is a rate.

In the G / B subframe period, the operation is the same as that in the R subframe period.
Therefore, the R component image is displayed in the R subframe period, the R component image is displayed in the G subframe period, and the R component image is displayed in the B subframe period. The primary color images overlap and are viewed as a full color image.

In FIG. 5, the straight lines descending to the right of the R, G, B first scanning period and the R, G, B second scanning period indicate that the selected line of the scanning line is progressing from top to bottom as time passes. Show. Although the scanning line selection period is actually a short straight line, it is sufficiently shorter than the time axis, so it is a continuous diagonal straight line.
The R light emission period, the G light emission period, and the B light emission period are set to the same period so that the irradiation intensity of each primary color is equal, in other words, to prevent the white balance from being lost.

  Here, what kind of image is visually recognized by the color sequential driving according to the first embodiment will be described with reference to FIG. In FIG. 8, the original image shown in (a) is displayed. Here, the color component is not specified as any one of R, G, and B.

First, in the first scanning period, when viewed on the display panel 100, a bright gradation is obtained with respect to two pixels in the same column vertically adjacent to an odd row and an even row adjacent to the odd row. Write data signal.
For example, in the original image shown in (a), the pixel in the first row and the third column is in a bright state as shown by □, and the pixel in the second row and third column is in the dark state of ■ (black □). When the scanning line of the second row is selected, as shown in (b), the data signal obtained by converting the video signal corresponding to the bright pixel of the first row and the third column is 1 for the third column. It is written in the pixel 110 in the row 3 column and the 2 row 3 column.
In the figure, “+” indicates a pixel (sampling pixel) to be read out of two pixels adjacent in the vertical direction.
In the original image, the pixels in 5 rows and 2 columns and 6 rows and 2 columns are both in the dark state of ■, so when the scanning line of the 5th and 6th rows is selected, A data signal obtained by converting the video signal corresponding to the pixel located at is written in the pixel 110 of 5 rows and 2 columns and 6 rows and 2 columns in (b). In (b), the pixel to which the data signal corresponding to the dark state (2) is written is indicated by a hatched square.

  Next, in the second scanning period, the image of the (primary color component) indicated by the video signal Vid is written to the respective pixels 110 on a one-to-one basis by the scanning lines for each row. As described above, an image of (primary color component) is formed by each pixel 110 as it is.

  As described above, according to the present embodiment, in the R, G, and B first scanning periods, the resolution is lower than that of the image defined by the video signal Vi d by preferential writing to the pixels in the light state having a slow optical response. After that, in the R, G, B second scanning period, an image having a resolution defined by the video signal Vid is formed, the resolution is made higher than that in the first scanning period, and the first scanning is performed. The light emission of the LED is started in the middle of the second scanning period after the waiting period has elapsed after the period has ended. For this reason, a bright screen can be displayed over a long light emission period, and light irradiation in a state where the optical response is insufficient is avoided to prevent an image different from the written content from being viewed. It becomes possible.

  In the first embodiment described above, the odd-numbered row and the subsequent even-numbered row are selected at the same time in the first scanning period. However, the first, second, third, fourth, fifth, sixth, seventh, Adjacent three rows may be selected simultaneously, such as rows 8 and 9... 766, 768, and 768, or four or more rows may be selected simultaneously. Even when three or more rows are simultaneously selected, a data signal obtained by converting a video signal of a pixel having a slower optical response among three or more pairs of pixels in the first scanning period may be written.

<Second Embodiment>
Next, color sequential driving according to the second embodiment of the present invention will be described. FIG. 9 is a diagram showing an outline of color sequential driving according to the second embodiment.
As shown in this figure, in the second embodiment, the R, G, B second scanning period is shorter than in the first embodiment. In the second embodiment, the R, G, and B first scanning periods are also different from those in the first embodiment, although they cannot be distinguished in FIG. Thus, hereinafter, the color sequential driving according to the second embodiment will be described focusing on these differences.

  First, when viewed in the R sub-frame period, in the R first scanning period, the control circuit 20 sets odd-numbered i (i is 1, 3, 5,..., 767) rows to the Y driver 130. Scanning signals G1, G2, G3,... Are controlled in such a manner that the selection voltage is simultaneously applied to the two rows of the odd number i row and the even number (i + 1) row one row below. , G768 are output as shown in FIG. 6, the polarity is designated for the data signal conversion circuit 40, and the data signal Vs is sent to the X driver 140 by 1, 2, 3,. The point that the data lines 114 in the column are controlled to be sampled in order is the same as in the first embodiment.

However, when the selection voltage is applied to the odd-numbered i-th row and the even-numbered (i + 1) -th row at the same time, the control circuit 20 causes the image processing circuit 30 to select the next video signal stored in the internal memory. Is selected, the odd-numbered i-th row or even-numbered (i + 1) -th row is selected, and the selected one pixel row is assigned 1, 2, 3, ..., 1024 columns. It is different from the first embodiment in that it is controlled to read in order.
In other words, the criterion here refers to which row when the gradations of the odd-numbered i-th row of pixels selected simultaneously and the even-numbered (i + 1) -th row of pixels are compared with each other. Is determined to be bright, and the row determined to be bright is selected.
In order to determine which line is brighter, for example, the gradation value is accumulated for one line, the magnitude of the accumulated value is judged, or the pixel whose gradation value exceeds a predetermined threshold value. For example, judging the magnitude of numbers.

Next, in the R second scanning period, the control circuit 20 does not read the video signal to the Y driver 130 among the odd-numbered rows selected simultaneously in the R-scanning first period and the even-numbered rows following the odd-numbered rows. Are selected in order from the top, and the image signal of the selected row is selected from among the video signals stored in the internal memory. 3,..., 1024 columns are controlled to be read out in order, and the polarity is designated for the data signal conversion circuit 40.
The number of scanning lines selected in the R second scanning period in the second embodiment is the number of scanning lines from which no video signal was read out in the R first scanning period, and is half of the total of 768 rows. Therefore, the R second scanning period in the second embodiment is half of the R second scanning period in the first embodiment, and is equal to the R first scanning period.

  Next, what kind of image is visually recognized by the color sequential driving according to the second embodiment will be described with reference to FIG. In FIG. 10 as well, the original image shown in (a) is displayed, and the color components are not specified.

First, in the first scanning period, when viewed on the display panel 100, an odd-numbered row and an even-numbered row adjacent to the odd-numbered row are selected at the same time, but the data signal to be written is applied to the pixels in the brighter row. Corresponding.
In the original image shown in (a), for example, when the first and second lines are compared, the number of □ in the bright state is larger in the first line, so the first and second scanning lines are selected. As shown in (b), a data signal obtained by converting the video signal read corresponding to the pixel in the first row is written.
In the original image, when the third and fourth lines are compared, the number of □ in the bright state is equal to each other. Therefore, when the scanning lines of the third and fourth lines are selected, A data signal obtained by converting a video signal corresponding to the pixel in the third row located above is written. In the original image, when comparing the fifth and sixth lines, the number of □ in the bright state is larger in the sixth line. Therefore, when the fifth and sixth scanning lines are selected, the sixth line image A data signal obtained by converting the signal is written. In the original image, when the 7th and 8th lines are compared, the number of □ in the bright state is equal to each other. A data signal obtained by converting the video signal corresponding to the eye pixel is written. In (b), the pixel to which the data signal corresponding to the dark state (2) is written is indicated by a hatched square.

Next, in the second scanning period, among the odd-numbered rows selected at the same time in the R-scanning first period and the even-numbered rows following the odd-numbered rows, the scanning lines in the row where the video signal is not read are sequentially from the top. Selected. In the R first scanning period, the video signals in the first, third, sixth, seventh,... Rows are read out. In this R second scanning period, as shown in FIG. , 8... Scanning line is selected, and the video signal of the selected row is read out and converted into a data signal and written.
Here, in (c), for example, for pixels in 2 rows, 4 columns, 4 rows, 3 columns, and 4 rows and 5 columns, optical writing is performed in the second scanning period after writing in a dark state is performed in the first scanning period. Since writing is performed in a slow bright state, there is a high possibility that the optical response does not correspond to the writing, but the other pixels are considered to have an optical response corresponding to the writing.
For this reason, in the second embodiment, a bright screen can be displayed with a long light emission period, and irradiation with light in a state where the optical response is insufficient is avoided, and an image different from the written content is visually recognized. It is possible to prevent this from happening.

  In the second embodiment, three or more rows may be simultaneously selected in the first scanning period. Even when three or more rows are selected simultaneously, it is only necessary to read out the video signal of the row in which the pixel with the slower optical response is dominant and write the data signal obtained by converting the video signal. In this case, in the second scanning period, the scanning lines in the rows that are not read in the first scanning period may be selected in order.

  In the above-described embodiment, the case where the optical response when changing to the bright state is slower than the optical response when changing to the dark state has been described. When the optical response at the time of change is slower than the optical response at the time of changing to the bright state, the dark pixels may be read and written with priority.

In the embodiment described above, in the embodiment, the primary colors to be used are R, G, and B, and the frame period is divided into three subframe periods corresponding to these colors. However, the primary colors are four or more. The frame period may be divided into four or more subframe periods corresponding to the primary colors used. For example, among R, G, and B, G is divided into YG (yellowish green) closer to the short wavelength and EG (emerald green) closer to the long wavelength, and these four colors correspond to the frame period. Then, it may be divided into four subframe periods.
When four or more primary colors are used, two or more dichroic prisms are required. In the case of using the above-described R, YG, EG, and B, another dichroic prism is arranged in the 9 o'clock direction of the dichroic prism 13 in FIG. 1, and YG and EG light is incident on two of them. Thus, the configuration may be such that it leads to the dichroic prism 13.
The present invention can be applied not only to the projection type that enlarges and projects the transmission image of the display panel 100 but also to the direct view type that switches the light source of the backlight for each primary color. Further, the pixel 110 is not limited to the transmissive type, and may be a reflective type.

It is a figure which shows the structure of the projector to which the drive method which concerns on 1st Embodiment is applied. FIG. 2 is a block diagram showing an electrical configuration of the projector. It is a figure which shows the structure of the pixel in the display panel of the projector. It is a figure which shows the optical response of the pixel (liquid crystal element) in the display panel. It is a figure which shows the drive method. It is a figure which shows the 1st scan of the drive method. It is a figure which shows the 2nd scanning of the drive method. It is a figure which shows the example of a display by the drive method. It is a figure which shows the drive method which concerns on 2nd Embodiment. It is a figure which shows the example of a display by the drive method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Projector, 11R, 11G, 11B ... LED, 20 ... Control circuit, 30 ... Image processing circuit, 100 ... Display panel, 105 ... Liquid crystal, 120 ... Liquid crystal element, 130 ... Y driver, 140 ... X driver

Claims (7)

A plurality of pixels each having a transmittance or a reflectance according to the written information;
Irradiation means for sequentially irradiating the plurality of pixels with light of at least three primary colors different from each other;
With
Dividing the unit period into subframe periods corresponding to the primary colors,
In each subframe period, primary color component information corresponding to the subframe period is written to the plurality of pixels by a first scan and a second scan following the first scan,
In the first scan, the same information is written to two or more pixels adjacent to each other to form an image having a resolution lower than the resolution defined by the plurality of pixels,
Information to be written to the two or more pixels in the first scan is determined based on the image information of the two or more pixels from the image information of any of the two or more pixels;
By the second scan, an image having a higher resolution than the low resolution is formed,
The driving method of the electro-optical device, wherein the irradiation unit irradiates the plurality of pixels with light of the primary color after the first scanning and before the first scanning in the next subframe period. Each of the plurality of pixels includes a liquid crystal element,
When the response time when the transmittance or reflectance of the liquid crystal element is changed from the increasing side to the decreasing side is shorter than the response time when changing from the decreasing side to the increasing side,
In the first scan, information to be written to the two or more pixels is image information of the brightest pixel among the image information of the two or more pixels,
In the opposite case,
The method for driving an electro-optical device according to claim 1, wherein information to be written to the two or more pixels is determined as image information of the darkest pixel among the image information of the two or more pixels. 3. The driving of the electro-optical device according to claim 1, wherein information on a pixel that has not been written in the two or more pixels in the first scan is written in a corresponding pixel in the second scan. Method. The plurality of pixels are:
Arranged corresponding to the intersection of a plurality of rows of scanning lines and a plurality of columns of data lines, and when the scanning lines are selected, the voltage of the data signal supplied to the data lines is written,
In the first scan, the odd-numbered scanning lines and the even-numbered scanning lines adjacent to the odd-numbered scanning lines are selected as a set in the predetermined direction and simultaneously,
When one set of odd-numbered and even-numbered scanning lines is selected at the same time, the brightness information of two pixels corresponding to the intersection of the scanning lines of the two rows and the one data line is compared. Brightness information as a representative value,
The driving method of the electro-optical device according to claim 1, wherein a voltage data signal based on brightness information determined as the representative value is supplied to the one data line. Each of the plurality of pixels includes a liquid crystal element,
When the response time when the transmittance or reflectance of the liquid crystal element is changed from the increasing side to the decreasing side is shorter than the response time when changing from the decreasing side to the increasing side,
In the first scan, the brightness information of the brighter one of the brightness information of the two pixels is determined as a representative value,
In the opposite case,
The method of driving an electro-optical device according to claim 4, wherein, in the first scan, darkness information of brightness information of the two pixels is determined as a representative value. 6. The electricity according to claim 4, wherein, in the first scan, information of a pixel that has not been determined as a representative value among the two pixels is written in a corresponding pixel in the second scan. Driving method of optical device. A plurality of pixels each having a transmittance or a reflectance according to the written information;
Irradiation means for sequentially irradiating the plurality of pixels with light of at least three primary colors different from each other;
Dividing the unit period into subframe periods corresponding to the primary colors,
In each subframe period, primary color component information corresponding to the subframe period is written to the plurality of pixels by a first scan and a second scan following the first scan,
In the first writing, the same information is written to two or more pixels adjacent to each other to form an image having a resolution lower than the resolution defined by the plurality of pixels,
In the first scan, the same information is written to two or more pixels adjacent to each other to form an image having a resolution lower than the resolution defined by the plurality of pixels,
Information to be written to the two or more pixels in the first scan is determined based on the image information of the two or more pixels from the image information of any of the two or more pixels;
A drive circuit for forming an image with a resolution higher than the low resolution by the second scanning;
A control circuit that controls the irradiating unit to irradiate the plurality of pixels with light of the primary color after the first scan and before the first scan in the next subframe period;
An electro-optical device comprising:

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