JP2010243582A - Electro-optical device driving method and driving circuit, electro-optical device, and display driving program - Google Patents

Abstract

An electro-optical device driving method, a driving circuit, an electro-optical device, and an electro-optical device capable of effectively reducing power consumption for displaying an image for one screen including a row image composed of only a background color A display driving program is provided.
An electro-optical device driving method according to the present invention drives an electro-optical device that displays an image for one screen by displaying a row image, which is an image for one row, over a plurality of rows. A driving method of the apparatus, wherein a first step (S12) for specifying a row image consisting only of a background color among row images to be displayed in a plurality of rows, and the row image specified in the first step are displayed. And a second step (S13, S4) of selecting a line excluding the power line and displaying a line image.
[Selection] Figure 3

Description

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

  As is well known, the electro-optical device is provided at a position where a plurality of scanning electrodes (scanning lines) extending in the row direction, a plurality of signal electrodes (data lines) extending in the column direction, and the scanning electrodes and the signal electrodes intersect. And a gradation signal corresponding to the gradation (for example, binary gradation) of each pixel is transmitted via the signal electrode to each of the pixels corresponding to the selected scanning electrode. By supplying, the optical state of each pixel is changed. Many electro-optical devices display an image for one screen by sequentially selecting scan electrodes from the scan electrode of the first row to the scan electrode of the last row and sequentially changing the optical state of the pixels for each row.

  In Patent Document 1 below, a difference between row images to be displayed in each row is detected, a row selection order is set based on the detected difference, and a scan electrode is selected based on the set selection order. A technique for changing the scanning order of scanning electrodes according to an image to be displayed is disclosed. With this technique, the selection order can be set so that rows with small differences in line images (for example, differences in lightness, saturation, hue, etc.) can be selected continuously. Power consumption for display can be reduced. Specifically, the frequency at which the voltage of the data line changes when the selected row is switched is reduced, and power consumption due to the parasitic capacitance of the data line is reduced.

Japanese Patent Laid-Open No. 2005-77634

  By the way, if the technique disclosed in the above-mentioned Patent Document 1 is used, the scanning electrode is scanned in accordance with the image to be displayed. Therefore, the power consumption for displaying the image for one screen is surely reduced. I can. However, if there is a line image consisting of only the background color, such as the line spacing (line spacing between character strings) when displaying a character string consisting of multiple lines, for example, Since the optical state of many pixels changes when changing or when changing from a line spacing to a character string, there is a problem in that wasteful power consumption occurs due to an increase in the number of data lines on which the voltage changes. If such power consumption can be reduced, it is considered that further reduction of power consumption can be realized.

  The present invention has been made in view of the above circumstances, and is an electro-optical device capable of effectively reducing power consumption for displaying an image for one screen including a row image including only a background color. It is an object to provide a driving method, a driving circuit, an electro-optical device, and a display driving program.

In order to solve the above problems, a driving method of an electro-optical device according to the present invention is an electro-optical device that displays an image for one screen by displaying a row image, which is an image for one row, over a plurality of rows. A driving method of an electro-optical device for driving, wherein a first step of specifying a row image consisting only of a background color among the row images to be displayed in the plurality of rows, and a row image specified in the first step And a second step of displaying the row image by selecting a row excluding the row to be displayed.
According to the present invention, among the line images to be displayed on a plurality of lines, a line image consisting only of the background color is specified, and the lines except for the line on which the specified line image is to be displayed are selected and displayed. Is done. As a result, the number of changes in the optical state of the pixel in the portion where the optical state of many pixels changes (for example, the boundary between the line where the character string is displayed and the line where the line between the character strings is displayed) is reduced. Since it can be reduced, it is possible to effectively reduce the power consumption for displaying an image for one screen including a row image consisting of only the background color.
Further, in the driving method of the electro-optical device according to the aspect of the invention, the second step includes at least two row images to be displayed on the row selected to display the row image and unselected among the plurality of rows. A third step for respectively obtaining a Hamming distance from a row image to be displayed in a row; and a step for selecting a row on which a row image having the shortest Hamming distance obtained in the third step is to be displayed and displaying the row image. 4 steps are included.
According to the present invention, the hamming distance between the row image to be displayed in the row selected to display the row image and the row image to be displayed in at least two rows that are not selected among the plurality of rows is obtained, respectively. A row image on which a hamming distance is to be displayed is selected, and the row image is displayed. Thereby, the power consumption for displaying the image for one screen including the line image which consists only of a background color can be reduced more effectively.
Here, in the driving method of the electro-optical device according to the aspect of the invention, the third step may divide the plurality of rows into a plurality of blocks including a predetermined number of rows, and in any one of the plurality of blocks. Preferably, this is a step of obtaining a hamming distance between a row image to be displayed in the last selected row and a row image to be displayed in a row included in a block next to the block.
Alternatively, in the driving method of the electro-optical device according to the aspect of the invention, the third step may include a row image to be displayed on the row selected to display the row image and an unselected row among the plurality of rows. Preferably, it is a step of obtaining a hamming distance from a row image to be displayed in a predetermined number of rows close to the selected row.
Alternatively, in the driving method of the electro-optical device according to the aspect of the invention, in the third step, the row image to be displayed on the row selected to display the row image and all the rows that are not selected among the plurality of rows. It is preferable that the step of obtaining a Hamming distance from each of the row images to be displayed.
In the driving method of the electro-optical device according to the aspect of the invention, the fourth step may be selected to display the row image when there is a row image in which the Hamming distance obtained in the third step is zero. This is a step of selecting a line on which a line image having a Hamming distance of zero is to be displayed together with the line and displaying the line image.
An electro-optical device driving circuit for driving an electro-optical device that displays an image for one screen by displaying a row image, which is an image for one row, over a plurality of rows. In the above, the specifying means for specifying a line image consisting of only a background color from the row images to be displayed on the plurality of lines, and the lines excluding the line on which the line image specified by the specifying means is to be displayed are selected. And a display means for displaying the row image.
In the driving circuit of the electro-optical device according to the aspect of the invention, the display unit may display a row image to be displayed on a row selected to display the row image, and at least two rows that are not selected from the plurality of rows. A hamming distance with a line image to be displayed is obtained, a line where the obtained hamming distance is the shortest is selected, and the line image is displayed.
Here, in the driving circuit of the electro-optical device according to the aspect of the invention, the display unit may divide the plurality of rows into a plurality of blocks including a predetermined number of rows, and the last of any one of the plurality of blocks. It is preferable to obtain the hamming distance between the row image to be displayed in the selected row and the row image to be displayed in the row included in the block next to the block.
Alternatively, in the drive circuit of the electro-optical device according to the aspect of the invention, the display unit may display a row image to be displayed on the row selected to display the row image and an unselected row among the plurality of rows. It is preferable that the hamming distances with the row images to be displayed in a predetermined number of rows close to the selected row are respectively obtained.
Alternatively, in the drive circuit of the electro-optical device according to the aspect of the invention, the display unit may display the row image to be displayed on the row selected to display the row image and all the unselected rows among the plurality of rows. It is preferable to obtain the Hamming distance from the row image to be displayed.
In the electro-optical device drive circuit according to the present invention, when there is a row image having a hamming distance of zero, the display means has a hamming distance of zero along with the row selected to display the row image. A feature is that a row image to be displayed is selected and the row image is displayed.
The electro-optical device of the present invention includes an electro-optical device including a plurality of scanning lines extending in the row direction, a plurality of data lines extending in the column direction, and a plurality of pixels provided at intersections of the scanning lines and the data lines. The electro-optical device for driving the apparatus includes the drive circuit according to any one of the above, which displays the row image to be displayed on the plurality of rows by selecting the scanning line as the row.
The display drive program according to the present invention is a drive unit for an electro-optical device that drives an electro-optical device that displays an image for one screen by displaying a row image, which is an image for one row, over a plurality of lines. A display driving program for causing the computer to specify a row image consisting only of a background color among the row images to be displayed on the plurality of rows, and a row image specified by the specifying unit. Is selected as a display means for displaying the row image by selecting a row excluding the row to be displayed.
In the display drive program of the present invention, the display means displays the row image to be displayed on the row selected to display the row image, and at least two rows that are not selected among the plurality of rows. It is characterized in that a hamming distance from each power line image is obtained, a line on which the line image having the shortest hamming distance is to be displayed is selected, and the line image is displayed.

1 is a block diagram illustrating a main configuration of an electro-optical device and a drive circuit thereof according to a first embodiment of the present invention. 2 is a cross-sectional view of a portion including a pixel electrode 28, an electrophoretic element 29, and a common electrode 30 in the pixel G formed on the electrophoretic panel 21 in FIG. 3 is a flowchart illustrating a driving method of the electro-optical device according to the first embodiment of the invention. It is a figure which shows an example of the image data produced | generated by CPU11. FIG. 3 is a diagram illustrating an example of raster data developed by the graphic accelerator 16. It is a figure for demonstrating the power consumption reduced in 1st Embodiment of this invention. 6 is a flowchart illustrating a driving method of an electro-optical device according to a second embodiment of the invention. It is a figure for demonstrating the operation | movement in 2nd Embodiment of this invention. It is a figure for demonstrating operation | movement of the 1st modification in 2nd Embodiment of this invention. It is a figure for demonstrating operation | movement of the 2nd modification in 2nd Embodiment of this invention.

  Hereinafter, a driving method and driving circuit of an electro-optical device, an electro-optical device, and a display driving program according to an embodiment of the present invention will be described in detail with reference to the drawings. The embodiments described below show some aspects of the present invention and do not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention.

[First Embodiment]
FIG. 1 is a block diagram showing a main configuration of an electro-optical device and a drive circuit thereof according to a first embodiment of the present invention. As shown in FIG. 1, the electro-optical device 1 of this embodiment includes a CPU (Central Processing Unit) 11, a RAM (Random Access Memory) 12, a ROM (Read Only Memory) 13, a keyboard 14, and an I / O. (Input / Output) system 15, graphic accelerator 16, VRAM (Video RAM) 17, display controller 18, and display device 20. Each block except the keyboard 14 and the display device 20 is connected to each other via a bus 19.

  The CPU 11 reads out various programs and data such as a basic control program and a display driving program stored in the ROM 13, develops and executes these various programs and data in a work area provided in the RAM 12, and each of the electro-optical device 1 includes. Perform block control. Further, the CPU 11 generates image data for displaying characters and numbers designated on the keyboard 14 in accordance with a key operation signal output from the keyboard 14, and outputs the image data to the graphic accelerator 16.

  Further, the CPU 11 executes a predetermined image display process (details will be described later) each time the graphic accelerator 16 writes raster data to the VRAM 17. Then, the raster data stored in the VRAM 17 is read, and gate driver driving data and source driver driving data for driving a gate driver 22 and a source driver 23, which will be described later, are generated and output to the display controller 18, respectively. . Here, the raster data is data indicating the display state of each pixel G of the display device 20, and when the value is “0”, it indicates that white (background color) is displayed on the corresponding pixel G. When the value is “1”, this indicates that black is displayed on the corresponding pixel G.

  The RAM 12 provides a storage area required when the CPU 11 executes various processes such as the image display process according to various programs. For example, a work area for expanding various programs read from the ROM 13 and a memory area for expanding data related to various processes executed by the CPU 11 are provided. The ROM 13 stores a basic control program executed by the CPU 11, various application programs including a display drive program, data related to these programs, and the like.

  The keyboard 14 includes character keys, numeric keys, and various function keys. The keyboard 14 is used to input a user instruction and outputs a key operation signal corresponding to a key operated by the user. The I / O system 15 is connected to a keyboard 14 or the like and functions as an input / output interface between the CPU 11 and the keyboard 14 or the like. Note that key operation signals and the like output from the keyboard 14 are input to the CPU 11 via the I / O system 15.

  The graphic accelerator 16 expands the image data output from the CPU 11 into raster data and writes the raster data in the VRAM 17. The VRAM 17 stores raster data in accordance with a write request from the graphic accelerator 16 and outputs the raster data to the CPU 11 in accordance with a read request from the CPU 11. The display controller 18 distributes and outputs the gate driver driving data and the source driver driving data output from the CPU 11 to each of the gate driver 22 and the source driver 23 described later.

  The display device 20 is provided with an electrophoretic panel 21 in which a plurality of pixels G are arranged in an array, a gate driver 22 provided on the left side of the electrophoretic panel 21, and an upper side of the electrophoretic panel 21. A source driver 23. The electrophoretic panel 21 includes a pair of substrates that sandwich the electrophoretic element 29, and a plurality of scanning lines 24 are formed on one substrate so as to extend in the horizontal direction on the paper surface so as to intersect therewith. A plurality of data lines 25 are formed so as to extend in the vertical direction on the paper surface, and a pixel G is formed at each intersection.

  Each pixel G has a transistor 27 (here, an Nch thin film field effect transistor) as a switching element and a pixel electrode 28. The drain of each transistor 27 is connected to the pixel electrode 28, and the source corresponds to the pixel G. The gate is connected to the data line 25 and the gate is connected to the corresponding scanning line 24. A common electrode 30 common to all the pixel electrodes 28 is formed on the other substrate. The common electrode 30 is made of a transparent member. Note that the number of scanning lines 24 is n (n is an integer of 2 or more), and the number of data lines 25 is m (m is an integer of 2 or more). Each scanning line 24 is connected to a corresponding output of the gate driver 22, and each data electrode 25 is connected to a corresponding output of the source driver 23.

  FIG. 2 is a cross-sectional view of a portion including the pixel electrode 28, the electrophoretic element 29, and the common electrode 30 in the pixel G formed on the electrophoretic panel 21 in FIG. 1. As shown in FIG. 2, the pixel G of the electrophoresis panel 21 includes a layer L1 of the electrophoresis element 29 provided with a plurality of microcapsules 31, a common electrode 30 formed on the top surface of the layer L1, and a bottom surface of the layer L1. And a pixel electrode 28 formed on the substrate. Here, the common electrode 30 side is a viewing side surface, that is, a display surface. The microcapsule 31 provided in the layer L1 encloses an electrophoretic dispersion liquid 32 composed of black charged particles 32a and a white dispersion medium 32b. Here, it is assumed that the black charged particles 32a are positively charged.

  The gate driver 22 sets the scanning line 24 to a predetermined potential according to the gate driver driving data output from the display controller 18. Here, the gate driver driving data is a numeric string representing the potential of each scanning line 24 with a numeric value of “0” or “1”. For this reason, when the i-th value (i is an integer satisfying 1 ≦ i ≦ n) of the gate driver driving data is “0”, the gate driver 22 detects the i-th scanning line from the upper side of FIG. The potential of 24 is set to a non-selection voltage Vgl that is lower than the potential applied to the data line 25 and the common electrode 30. The voltage level of the non-selection voltage Vgl is also referred to as “L (low)” level. On the other hand, when the i-th numerical value of the gate driver driving data is “1”, the gate driver 22 sets the potential of the i-th scanning line 24 from the upper side of FIG. The selection voltage Vgh is higher than the potential applied to the voltage 30. The voltage level of the selection voltage Vgh is also referred to as “H (high)” level (scanning voltage).

  The source driver 23 sets the data line 25 to a predetermined potential according to the source driver driving data output from the display controller 18. Here, the data for driving the source driver is a numerical string in which the potential of each data line 25 is represented by a numerical value “0” or “1”. Therefore, when the j-th value (j is an integer satisfying 1 ≦ j ≦ m) of the source driver driving data is “0”, the source driver 23 determines that the j-th data line from the left side of FIG. The potential of 25 is set to Vsn equal to the potential applied to the common electrode 30. Hereinafter, the voltage level of Vsn is also referred to as “L” level. On the other hand, when the j-th numerical value of the source driver driving data is “1”, the source driver 23 applies the potential of the j-th data line 25 from the left side of FIG. Vsh is higher than the potential. Hereinafter, the voltage level of Vsh is also referred to as “H” level. Further, the source driver 23 is configured so that the potential of the data line 25 can be set to Vsl that is lower than the potential applied to the common electrode 30.

  In the display device 20 having the above configuration, the transistor 27 whose gate is connected to the scanning line 24 to which the selection voltage Vgh is applied is turned on, and the potential of the data line 25 and the pixel electrode 28 are equipotential. Thereafter, when the scanning line 24 is not selected and the non-selection voltage Vgl is applied, the transistor 27 is turned off. At this time, the potential of the pixel electrode 28 is maintained by a capacitive component (not shown) created by the pixel electrode 28. The electrophoretic element 29 has a property of changing its optical state when a voltage is applied and maintaining the state when the applied voltage is lost. Utilizing this property, for example, the following driving method is adopted in this embodiment.

  First, the selection voltage Vgh is applied to the scanning lines 24 of all rows, and the voltage Vsl lower than the potential applied to the common electrode 30 is applied to all the data lines. The scanning lines 24 may be selected all at the same time or sequentially scanned. At this time, in each pixel, the potential of the pixel electrode 28 is lower than the potential of the common electrode 30, positively charged black particles in the electrophoretic element 29 are adsorbed on the pixel electrode 28 side, and the common electrode 30 side is white dispersed. It becomes only the medium. Thereby, all the pixels are displayed in white.

  In this state, when a voltage Vsn that is equipotential to the common electrode 30 is applied to the data line, the potential of the pixel electrode 28 and the potential of the common electrode 30 become equal, and thereafter the non-selection voltage Vgl is applied to the scanning lines 24 of all rows. Even if it is applied, this display state is maintained. Strictly speaking, when the selection voltage changes to the non-selection voltage, the potential of the pixel electrode 28 changes due to the influence of a parasitic capacitance (not shown) formed at the gate of the transistor 27. This change is taken into consideration. Assume that the voltage Vsn is set so that the potential of the pixel electrode 28 and the potential of the common electrode 30 become equal after the change to the non-selection voltage.

  Next, the scanning lines 24 are selected in a predetermined order, and the voltage Vsh or the voltage Vsn is applied to the data lines 25. In a pixel to which the voltage Vsh is applied via the data line 25, the potential of the pixel electrode 28 is also the voltage Vsh. Then, the potential of the common electrode 30 is lower than that of the pixel electrode 28, and the black charged particles are adsorbed on the common electrode 30 side. Therefore, when observed from the common electrode 30 side, the pixel is displayed in black. In the pixel to which the voltage Vsn is applied via the data line 25, the potential of the pixel electrode 28 and the common electrode 30 remains equal, so that white display is maintained.

  Here, the order of selection of the scanning lines 24 will be described in detail later. Note that when the voltage Vsn is applied to the data line, the potentials of the pixel electrode 28 and the common electrode 30 become equal, so that the display is maintained regardless of whether the pixel is in white display or black display. That is, even when the electrophoresis panel 21 is turned off and no energy is supplied, the state where the charged particles 32a are attracted to the front side is maintained. As a result, the image displayed on the electrophoresis panel 21 before being turned off is continuously displayed on the electrophoresis panel 21 even after the electrophoresis panel 21 is turned off.

  Next, the operation of the electro-optical device 1 having the above configuration will be described in detail. FIG. 3 is a flowchart illustrating a driving method of the electro-optical device according to the first embodiment of the invention. In the following, for ease of explanation, the electrophoresis panel 12 includes “20” scanning lines 24 and “12” data lines 25, and two lines are arranged in the vertical direction in FIG. Assume that characters can be displayed side by side.

  First, it is assumed that the user presses the character keys “E” and “T” on the keyboard 14. Then, key operation signals corresponding to the character keys “E” and “T” are output from the keyboard 14 and input to the CPU 11 via the I / O system 15 and the bus 19. Then, the CPU 11 generates image data for displaying the character string “ET” as shown in FIG. 4 in accordance with the key operation signal (step S1).

  FIG. 4 is a diagram illustrating an example of image data generated by the CPU 11. As shown in FIG. 4, the image data created by the CPU 11 is “12” bits in which the number of bits in the horizontal direction of the paper is equal to the number of data lines 25, and the number of bits in the vertical direction of the paper is equal to the number of scanning lines 24. The “20” -bit data is data in which the portions corresponding to the characters “E” and “T” are displayed in black, and the values in the other portions are displayed in white (background color).

  The image data created by the CPU 11 is output from the CPU 11 to the graphic accelerator 16, and is developed into raster data by the graphic accelerator 16 as shown in FIG. 5 (step S2). FIG. 5 is a diagram showing an example of raster data developed by the graphic accelerator 16. As shown in FIG. 5, the developed raster data is data having a bit number (12 × 20 = 240 bits) equal to the product of the number of data lines 25 and the number of scanning lines 24, and is shown in FIG. This is data in which the value of the portion corresponding to the black portion is “1” and the value of the portion corresponding to the other white portion is “0”. The raster data created by the graphic accelerator 16 is written into the VRAM 17.

  When the above processing is completed, the raster data stored in the VRAM 17 is read out by the CPU 11 and the above-described image display processing is performed (step S3). When the image display processing is started, first, from the raster data read from the VRAM 17, a bit pattern (hereinafter referred to as a row image pattern) corresponding to a row image that is an image for one row displayed on each row of the electro-optical device 1. Then, a process of generating information (hereinafter referred to as a gate signal) indicating whether or not to display these row images is performed (step S11).

  Here, the above-described row image pattern is a numerical string that represents the state of each pixel G corresponding to each scanning line 24 with a numerical value “0” or “1”. For example, when the j-th numerical value in the numerical sequence is “0”, this indicates that white is displayed on the j-th pixel G from the left side in FIG. 1, and the j-th numerical value in the numerical sequence is In the case of “1”, black is displayed on the j-th pixel G from the left side in FIG. Further, the gate signal is a numeric string indicating whether or not to display a row image for each row by a numeric value “0” or “1”. For example, when the i-th numerical value of the numerical sequence is “0”, it indicates that no row image is displayed for the i-th row from the upper side of the drawing in FIG. 1, and the i-th numerical value of the numerical sequence is displayed. When “1” is “1”, it indicates that a row image is displayed for the i-th scanning line 24 from the upper side of the drawing in FIG.

  Next, processing for specifying a row image pattern whose numerical values are all “0” among the created row image patterns is performed. That is, a process of specifying a line image consisting only of white as the background color among the line images to be displayed in a plurality of lines is performed (step S12: first step). This process is performed in order to specify a line image consisting of only the background color, for example, between lines when displaying a character string consisting of a plurality of lines. When the image data shown in FIG. 4 is created, the line image patterns for the ninth to eleventh lines and the twentieth line between the character “E” and the character “T” are specified by such processing.

  Next, a process of setting the numerical value of the gate signal related to the row image pattern specified in step S12 to “0” is performed. When the image data shown in FIG. 4 is created, the row image pattern for the ninth to eleventh rows and the twentieth row is specified by the processing in step S12 described above. The ˜11th and 20th numerical values are set to “0”. The numerical value of the gate signal related to the row image pattern not specified in step S12 is set to “1” (step S13: second step). Finally, the row image pattern generated in step S11 and the gate signal set with a numerical value in step S13 are sequentially output to the display controller 18 as source driver driving data and gate driver driving data, respectively (step S14). . Thereby, the image display process performed by CPU11 is complete | finished.

  The source driver driving data and the gate driver driving data sequentially input to the display controller 18 are distributed and output to the gate driver 22 and the source driver 23, respectively, and electric power is supplied according to the source driver driving data and the gate driver driving data. The electrophoresis panel 21 is driven (step S4: second step). As a result, an image for one screen corresponding to the row image pattern and the gate signal is displayed on the electrophoresis panel 21.

  Specifically, when the image data created by the CPU 11 is the image data shown in FIG. 4, the first to eighth numerical values in the numerical sequence forming the gate signal (gate driver driving data) are “1”. . Therefore, the scanning lines 24 from the first row to the eighth row are sequentially set to the “H” level by the gate driver 22, and in accordance with the row image pattern (source driver driving data) in synchronization with this. A voltage is sequentially applied to each of the data lines 25 by the source driver 23. On the other hand, the ninth to eleventh numerical values in the numerical sequence forming the gate signal (gate driver driving data) are “0”. Therefore, the scanning lines 24 from the ninth row to the eleventh row are set to the “L” level by the gate driver 22 and are not scanned.

  The 12th to 19th numerical values in the numerical sequence forming the gate signal (gate driver driving data) are “1”. Therefore, similarly to the scanning lines 24 from the first line to the eighth line, the scanning lines 24 from the twelfth line to the nineteenth line are sequentially set to the “H” level by the gate driver 22, and In synchronization with this, a voltage corresponding to the row image pattern (source driver driving data) is applied to each of the data lines 25 by the source driver 23. Since the 20th numerical value of the numerical value sequence forming the gate signal (gate driver driving data) is “0”, the 20th scanning line 24 is set to “L” level by the gate driver 22 and is not scanned.

  As described above, in the present embodiment, among the row images to be displayed in a plurality of rows, the row image consisting only of the background color is specified, and the specified row image is displayed (the ninth to eleventh rows in FIG. 4). A row image is displayed by selecting rows (the first to eighth rows and the twelfth to nineteenth rows in FIG. 4) excluding the first and twentieth rows). For this reason, for example, when changing from a character string to a line and when changing from a line to a character string, the optical state of the pixel does not change, so an image for one screen including a line image consisting only of the background color The power consumption for displaying can be effectively reduced.

  FIG. 6 is a diagram for explaining the power consumption reduced in the first embodiment of the present invention. FIG. 6 shows the number of pixels G whose optical state needs to be changed when each row is displayed when the image data shown in FIG. 4 is displayed by the electro-optical device 1. In FIG. 6, the hatched rows indicate the spaces between the rows (rows not selected in the present embodiment), and the pixels G that need to be changed in the first row are excluded.

  As shown in FIG. 6, conventionally, in the ninth line changing from the letter “E” to the line and the twelfth line changing from the line to the letter “T”, the optical states of the seven pixels G are respectively changed. It was necessary to change. Further, it is necessary to change the optical state of one pixel G in the 20th row. On the other hand, in the present embodiment, the ninth to eleventh lines that are between the lines are not selected, and the twelfth line is selected after the eighth line. The row images used for displaying the eighth and twelfth rows are the same. For this reason, the number of pixels G whose optical state needs to be changed from the eighth row to the twelfth row becomes zero. In addition, the number of pixels G whose optical state needs to be changed is zero for the twentieth row. Note that the number of changes in the optical state is the number of data lines 25 that need to change the voltage of the data lines 25 when displaying a certain line and displaying the next line. The power consumption due to the parasitic capacitance is proportional, and the power consumption due to the parasitic capacitance of the data line 25 occupies most of the display device 20.

  The total number of pixels G whose optical state needs to be changed from the second row to the twentieth row is “45” in the related art as shown in FIG. ”, A reduction of about 33%. If the power consumption of the display device 20 is approximately proportional to the number of pixels G that need to change the optical state, in this embodiment, the power consumption can be reduced by about 33%.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The electro-optical device and the drive circuit thereof according to the present embodiment have the same configuration as the electro-optical device and the drive circuit according to the first embodiment described above. However, in the present embodiment, the processing performed by the CPU 11 based on various programs stored in the ROM 13 is different from the first embodiment.

  Specifically, in the first embodiment described above, a row image consisting of only the background color is specified by specifying a row image pattern whose numerical values are all “0”, and the row where this row image is displayed is excluded. A line image was displayed by selecting a line. In this embodiment, in addition to specifying a row image consisting of only the background color, the row image is displayed in consideration of the Hamming distance. Here, the Hamming distance is the number of different characters at corresponding positions in two character strings having the same number of characters. For example, the Hamming distance between the character string “AAA” and the character string “AAA” is “0”, and the Hamming distance between the character string “AAA” and the character string “AAB” is “1”.

  FIG. 7 is a flowchart illustrating a driving method of the electro-optical device according to the second embodiment of the invention. As in the first embodiment, the present embodiment also includes “20” scanning lines 24 and “12” data lines 25, and displays two characters side by side in the vertical direction of the paper in FIG. A case where the letter “E” and the letter “T” are displayed on the possible electrophoresis panel 12 will be described as an example.

  When the user depresses the character keys “E” and “T” on the keyboard 14, image data for displaying the character string “ET” shown in FIG. 4 is generated by the CPU 11 as in the first embodiment (step S1). The image data is developed into raster data shown in FIG. 5 by the graphic accelerator 16 (step S2) and written into the VRAM 17. When the above processing is completed, raster data stored in the VRAM 17 is read out by the CPU 11 and image display processing is performed (step S3).

  When the image display process is started, a row image pattern and a gate signal are generated from the raster data as in the first embodiment (step S11), and all the numerical values of the created row image patterns are “0”. A process for specifying a row image pattern is performed (step S12). Next, a process of setting the numerical value of the gate signal related to the row image pattern specified in step S12 to “0” is performed (step S13).

  Next, after the row image pattern is divided into a plurality of blocks, a Hamming distance is calculated to determine a row selection order (step S20: third and fourth steps). FIG. 8 is a diagram for explaining the operation in the second embodiment of the present invention. In FIG. 8, the line image pattern handled by the CPU 11 is represented by image data for easy understanding. As shown in FIG. 8, the row image patterns of the first to twentieth rows are divided into blocks B1 to B7. The blocks B1 to B6 include the row image patterns from the first to the 18th rows in order of three rows, and the block B7 includes the row image patterns for the two rows of the 19th and 20th rows.

  Note that the row image pattern of the 0th row in FIG. 8 is a virtual row image pattern used for calculating the Hamming distance from the row image pattern of the first row. In general, the first row is selected after the last row (the 20th row in the example shown in FIG. 8) is selected. Therefore, the first row is replaced with the row image pattern of the 0th row in FIG. The Hamming distance from the first row image pattern may be calculated using the row image pattern.

In this embodiment, the Hamming distance is obtained in units of the blocks B1 to B7, and the row selection order is determined. Specifically, the order of selecting rows is determined by the following procedures (1) and (2).
(1) The Hamming distance between the last selected row in the block selected before the block for which the Hamming distance is obtained (target block) and each row included in the target block is obtained, and the Hamming distance is the shortest. A row is determined to be the first row to be selected in the target block. (2) In the target block, the hamming distance between the row determined as the first row to be selected and the remaining rows is obtained, and the hamming distance is short. The rows to be selected are determined in order.

Here, if the two row image patterns are Pa and Pb, respectively, the Hamming distance dH of these row image patterns Pa and Pb is calculated using the following equation.
dH = d (Pa, Pb) = Σ (Paj (XOR) Pbj)
However, Paj and Pbj in the above formulas indicate the jth numerical value of the numerical sequence forming the row image patterns Pa and Pb, respectively, and (XOR) indicates exclusive OR. Σ () is a function that sequentially performs the operations in parentheses from j = 1 to j = n and adds the results of the operations.

  Next, the process performed in step S20 will be specifically described with reference to FIG. First, the first block B1 is selected, and the hamming distances between the row image patterns of the first to third rows and the row image pattern of the zeroth row included in the block B1 are obtained. Here, the Hamming distances are determined as “7”, “1”, and “1” for the first to third row image patterns. For this reason, the selection order of the rows in the block B1 is determined in the order of the second row, the third row, and the first row.

  Next, the second block B2 is selected, and the fourth to sixth row image patterns and the first row image pattern (the row image of the row selected last in the block B1) included in the block B2. Hamming distance from each pattern is determined. Here, for the fourth to sixth row image patterns, the Hamming distances are obtained as “0”, “6”, and “6”. For this reason, the selection order of the rows in the block B2 is determined in the order of the fourth row, the fifth row, and the sixth row.

  Next, the third block B3 is selected, and the row image pattern of the seventh to ninth rows and the row image pattern of the sixth row (the row image pattern of the row selected last in the block B2) included in this block B3. ) And the Hamming distance from each other. However, in the process of step S12 performed previously, the row image pattern of the ninth row is specified as a row image pattern whose numerical values are all “0”. For this reason, in block B3, the Hamming distance between the row image pattern of the seventh and eighth rows and the row image pattern of the sixth row excluding the specified row image pattern of the ninth row is obtained.

  Here, the Hamming distances are determined as “0” and “6” for the row image patterns of the seventh and eighth rows. For this reason, the selection order of the rows in the block B3 is determined in the order of the seventh row and the eighth row. The same processing as described above is performed for the other blocks B4 to B7, and the selection order for the rows excluding the row specified in step S12 is sequentially determined based on the Hamming distance.

  In FIG. 8, the number of pixels G whose optical state needs to be changed when each row is displayed is displayed as the “number of switching”. Referring to FIG. 6, the total number of switching when displaying the character string “ET” is “45” in the related art, and “30” in the first embodiment. On the other hand, in the present embodiment, the total number of switching is “19”, which is reduced by 58% compared to the conventional case.

  The row image pattern for which the selection order has been determined by the above processing and the gate signals for which numerical values have been set in step S13 are sequentially output to the display controller 18 as source driver driving data and gate driver driving data, respectively (step S14). ). The source driver driving data and the gate driver driving data are distributed and output to the gate driver 22 and the source driver 23, respectively, and the electrophoretic panel 21 is driven according to the source driver driving data and the gate driver driving data. (Step S4: Fourth step). As a result, an image for one screen corresponding to the row image pattern and the gate signal is displayed on the electrophoresis panel 21.

  As described above, in the present embodiment, among the row images to be displayed in a plurality of rows, the row image consisting only of the background color is specified, and the Hamming distance between the row images is obtained for the rows excluding the specified row. The selection order of rows is determined. For this reason, the power consumption for displaying the image for 1 screen containing the line image which consists only of background colors can be reduced more effectively than 1st Embodiment.

  FIG. 9 is a diagram for explaining the operation of the first modified example in the second embodiment of the present invention. In the second embodiment described above, the row image pattern is divided into a plurality of blocks and the Hamming distance is calculated to determine the row selection order in step S20 shown in FIG. On the other hand, in this modified example, the row image pattern is not divided into blocks, and humming is performed with a predetermined number of rows (here, 3 rows) close to (located in the vicinity of) the selected row. Each of the distances is calculated, and the line selection order is determined by selecting the line with the shortest Hamming distance as the next line. Here, when setting a line close to the selected line, the line already selected is excluded. Therefore, for example, when the third row is selected in FIG. 9 and the like and the first, second, fourth, fifth, sixth and eighth rows are already selected, the closest row to the third row is The seventh row and the second closest row are the ninth row. This will be specifically described below.

  First, the first row (here, the second row) is selected, and the unselected three rows (first, third, and fourth rows) of row images close to the row image pattern of the first row. A hamming distance from the pattern is obtained. In the example shown in FIG. 9, since the Hamming distance for the third row is the shortest, the third row is determined as the second selected row. Next, the Hamming distance between the newly selected row image pattern of the third row and the row image pattern of the unselected three rows (first, fourth, fifth rows) close to the third row is respectively Desired. In the example shown in FIG. 9, since the Hamming distance for the fifth row is the shortest, the fifth row is determined as the third selected row.

  Next, the Hamming distances between the newly selected row image pattern of the fifth row and the unselected row image patterns of the third row (first, fourth, sixth rows) close to the fifth row are obtained. It is done. In the example shown in FIG. 9, since the Hamming distance for the sixth row is the shortest, the sixth row is determined as the fourth selected row. Next, the Hamming distance between the newly selected row image pattern of the sixth row and the unselected row image patterns of the third row (first, fourth, seventh rows) close to the sixth row is respectively Desired. In the example shown in FIG. 9, since the Hamming distance for the seventh row is the shortest, the seventh row is determined as the fifth selected row.

  Next, the Hamming distance between the newly selected row image pattern of the seventh row and the unselected row image patterns of the third row (first, fourth, eighth rows) close to the seventh row is obtained. It is done. In the example shown in FIG. 9, since these hamming distances are equal and shortest, the first row is determined as the sixth selected row. Next, the Hamming distance between the newly selected row image pattern of the first row and the unselected row image patterns of the third row (fourth, eighth, and twelfth rows) close to the first row is respectively Desired. Note that the row image patterns in the ninth to eleventh rows are excluded because they are specified as row image patterns having numerical values of all “0” in the process of step S12.

  The same processing as described above is sequentially performed, and the selection order for the rows excluding the row specified in step S12 is sequentially determined based on the Hamming distance. Here, as shown in FIG. 9, in the present modification, the total number of switching when displaying the character string “ET” is “13”. For this reason, it is reduced by 71% compared to the conventional “45”. For this reason, the power consumption for displaying the image for 1 screen containing the line image which consists only of background colors can be reduced more effectively than 1st, 2nd embodiment.

  FIG. 10 is a diagram for explaining the operation of the second modified example in the second embodiment of the present invention. In the first modification of the second embodiment described above, in step S20 shown in FIG. 7, the row image pattern is not divided into blocks, and a predetermined number of rows that are not yet selected among the rows close to the selected row. The Hamming distance of each row is calculated, and the row selection order is determined by selecting the row with the shortest Hamming distance as the next row. On the other hand, in this modification, the Hamming distance between the row image pattern of the selected row and all the remaining row image patterns is calculated to determine the row selection order.

  In this modification, as shown in FIG. 10, the selection order of the rows is the second row, the third row, the fifth row, the sixth row, the seventh row, the thirteenth row,. It is determined. Also, as shown in FIG. 10, in the present modification, the total number of switching when displaying the character string “ET” is “9”, which is 80% less than the conventional “45”. For this reason, the power consumption for displaying the image for 1 screen containing the line image which consists only of background colors can be reduced more effectively than said 1st modification.

  In the above, the driving method and driving circuit of the electro-optical device, the driving circuit, the electro-optical device, and the display driving program according to the embodiment of the present invention have been described. However, the present invention is not limited to the above-described embodiment and is within the scope of the present invention. Can be changed freely. For example, in the above-described second embodiment and its modification, the example in which the selection order of multiple rows (order for performing sequential selection) is determined based on the Hamming distance has been described, but there is a row image with a Hamming distance of zero. In this case, it is also possible to simultaneously display the respective row images by simultaneously selecting the rows on which those row images are displayed.

  In the above-described embodiment, an example has been described in which row images including only the background color are sequentially specified from image data of one screen, and further, the selection order of rows is sequentially determined. However, data specifying the row image consisting only of the background color and data indicating the selection order of the rows are prepared in advance as attribute data accompanying the image data, and the scanning line is selected based on the attribute data. Thus, an image for one screen may be displayed on the electrophoresis panel 21. This eliminates the need for hardware and software for obtaining the scanning line selection order, thereby further reducing power consumption.

  In the above embodiment, the case where the electrophoretic panel 12 is an active matrix panel using TFT (Thin Film Transistor) has been described as an example. However, the present invention can be applied even to an active matrix drive using an active element (active element) such as a TFD (Thin Film Diode). Further, the structure may be a so-called COF (Chip on Film) type structure or a structure having a structure for directly mounting an IC chip.

  In the above-described embodiment, the electro-optical device including the electrophoretic panel 12 has been described as an example. However, the present invention is applied to any electro-optical device including a display device that performs display using a combination of data lines and scanning lines. Is possible. For example, the present invention is also applied to an electro-optical device including a display device such as a TN (Twisted Nematic) liquid crystal display, an STN (Super TN) liquid crystal display, a ferroelectric liquid crystal display, a cholesteric liquid crystal display, a toner display, and a twist ball display. be able to.

  Furthermore, the electro-optical device of the present invention is not limited to a liquid crystal device, and other electro-optical devices such as an organic EL device, an inorganic EL device, a plasma display device, an electrophoretic display device, a field emission display device, It can be applied to LED, electronic paper and the like. As described above, various electro-optical elements can be used as long as they are compatible with the driving method of the present invention.

  In the above embodiment, an example in which the CPU 11 executes the image display process has been described. However, for example, the graphic accelerator 16, the display controller 18, or the source driver 23 including the VRAM 17 may be used. In the case of execution by the source driver 23, it is necessary to provide a signal line for connecting the source driver 23 and the gate driver 22.

  In the above embodiment, when the numerical value constituting the row image is “0”, the corresponding pixel G is displayed in white, and when “1” is present, the corresponding pixel G is displayed in black. An example is shown. However, conversely, when the numerical value constituting the row image is “0”, it indicates that the corresponding pixel G is displayed in black, and when “1” is present, it indicates that the corresponding pixel G is displayed in white. Anyway. Further, for example, when “0” is included in the numerical value constituting the row image, it indicates that the corresponding pixel G is displayed in white, and when “9” is present, it indicates that the corresponding pixel G is displayed in black. When there is a numerical value between “0” and “9”, it may be indicated that the corresponding pixel G is displayed with gray of lightness corresponding to the numerical value.

DESCRIPTION OF SYMBOLS 1 ... Electro-optical device, 11 ... CPU, 13 ... ROM, 18 ... Display controller, 20 ... Display device, 21 ... Electrophoresis panel, 22 ... Gate driver, 23 ... Source driver, 24 ... Scan line, 25 ... Data line, B1-B7 ... Block

Claims (15)

An electro-optic device driving method for driving an electro-optic device that displays an image for one screen by displaying a row image that is an image for one row over a plurality of rows,
A first step of identifying a row image consisting only of a background color among the row images to be displayed in the plurality of rows;
And a second step of displaying the row image by selecting a row excluding the row on which the row image specified in the first step is to be displayed. In the second step, a Hamming distance between a row image to be displayed on a row selected to display the row image and a row image to be displayed on at least two rows that are not selected among the plurality of rows is set. A third step to find,
The electro-optical device according to claim 1, further comprising: a fourth step of selecting a row on which the row image having the shortest Hamming distance obtained in the third step is to be displayed and displaying the row image. Driving method.   The third step divides the plurality of rows into a plurality of blocks including a predetermined number of rows, and a row image to be displayed in a row selected last in any one of the plurality of blocks; 3. The driving method for an electro-optical device according to claim 2, wherein the hamming distance from the row image to be displayed in the row included in the block next to the block is obtained.   The third step displays a row image to be displayed on a row selected to display the row image and a predetermined number of rows close to the selected row among unselected rows of the plurality of rows. 3. The method of driving an electro-optical device according to claim 2, wherein the hamming distance to the row image to be obtained is obtained.   The third step obtains a Hamming distance between a row image to be displayed on a row selected to display the row image and a row image to be displayed on all unselected rows of the plurality of rows. The method of driving an electro-optical device according to claim 2, wherein the method is a step.   In the fourth step, when there is a row image having a hamming distance of zero obtained in the third step, a row image having a hamming distance of zero is selected together with the row selected to display the row image. 6. The method of driving an electro-optical device according to claim 2, wherein the row image is displayed by selecting a row to be displayed. In a drive circuit for an electro-optical device that drives an electro-optical device that displays an image for one screen by displaying a row image that is an image for one row over a plurality of rows,
A specifying means for specifying a row image consisting only of a background color among the row images to be displayed in the plurality of rows;
A drive circuit for an electro-optical device, comprising: a display unit that selects a row excluding a row on which the row image specified by the specifying unit is to be displayed, and displays the row image.   The display means obtains a hamming distance between a row image to be displayed on a row selected to display the row image and a row image to be displayed on at least two rows not selected from the plurality of rows. 8. The drive circuit for an electro-optical device according to claim 7, wherein a row image on which the calculated Hamming distance is the shortest is selected and the row image is displayed.   The display means divides the plurality of rows into a plurality of blocks including a predetermined number of rows, a row image to be displayed in a row selected last in any one of the plurality of blocks, 9. The drive circuit for an electro-optical device according to claim 8, wherein a Hamming distance from a row image to be displayed in a row included in a block next to the block is obtained.   The display means displays a row image to be displayed on a row selected to display the row image and a predetermined number of rows close to the selected row among unselected rows of the plurality of rows. 9. The driving circuit for an electro-optical device according to claim 8, wherein a Hamming distance from the power row image is obtained.   The display means obtains a Hamming distance between a row image to be displayed on a row selected to display the row image and a row image to be displayed on all unselected rows of the plurality of rows. The drive circuit of the electro-optical device according to claim 8.   When there is a row image having a hamming distance of zero, the display means selects the row to display the row image of which the hamming distance is zero together with the row selected to display the row image. 12. The drive circuit for an electro-optical device according to claim 8, wherein a row image is displayed. In an electro-optical device that drives an electro-optical device including a plurality of scanning lines extending in a row direction, a plurality of data lines extending in a column direction, and a plurality of pixels provided at intersections of the scanning lines and the data lines ,
13. An electro-optical device comprising the drive circuit according to claim 7, wherein the scanning circuit is selected as the row and a row image to be displayed on the plurality of rows is displayed. A display drive program that causes a computer to function as a drive unit of an electro-optical device that drives an electro-optical device that displays an image of one screen by displaying a row image that is an image of one row over a plurality of lines. And
A specifying means for specifying a row image consisting only of a background color among the row images to be displayed on the plurality of rows;
A display driving program that functions as display means for displaying a line image by selecting a line excluding a line on which the line image specified by the specifying means is to be displayed.   The display means obtains a hamming distance between a row image to be displayed on a row selected to display the row image and a row image to be displayed on at least two rows not selected from the plurality of rows. 15. The display driving program according to claim 14, wherein a row image on which the calculated Hamming distance is the shortest is selected and the row image is displayed.

Images