JP2006243329A - Display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display apparatus 100 constituted so that a second display module 20 of passive drive method is stacked on a first display module 10 of active drive method, and to effectively use high-speed drawing property of the first display module 10 and display holding property of the second display module 20. <P>SOLUTION: When starting display of characters, drawing is performed by the first display module 10 and the whole area of the second display module is made to be in transmissive state (step S1, S2). After the first display module 10 performs drawing, the same content as the content drawn by the first display module 10 is drawn by the second display module 20 and the area of the first display module 10 corresponding to the lines drawn by the second display module 20 is made black (step S3). After the second display module 20 draws all the lines, liquid crystal driving of and power supply to the first display module 10 is turned off (step S5) in such a state that all the area corresponding to the lines is drawn in black, and liquid crystal driving of and power supply to the second display module 20 is turned off (step S6). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display device capable of displaying images and characters.

  Thin display devices are widely used in electronic devices such as mobile phones, digital cameras, and PDAs. In a display device using a nematic liquid crystal element, an image formed on the liquid crystal element is visualized by illuminating a transmissive liquid crystal element whose transmittance is controlled for each pixel from the back. Since the liquid crystal element itself does not emit light, an illumination member (for example, a backlight) that illuminates the liquid crystal element is required. There is also known a display device in which an organic EL (electroluminescence) element that emits light from the element itself is used instead of a liquid crystal element, and a backlight member is unnecessary. The configuration of such a liquid crystal display device or organic EL display device is disclosed in, for example, Patent Document 1 and Patent Document 2.

  On the other hand, as display devices such as so-called electronic paper and electronic book (registered trademark), those using cholesteric liquid crystal or PN liquid crystal (polymer network liquid crystal) are known (see, for example, Patent Document 3 and Patent Document 4). These use external light as illumination light, and are configured so that the transmission state / reflection state of the liquid crystal element can be switched for each pixel. The pixels switched to the reflective state diffusely reflect external light and are visually recognized as whitish in, for example, the PN liquid crystal, and the pixels switched to the transmissive state transmit external light. When an absorption layer such as a black plate that absorbs external light is provided below the liquid crystal, the pixel is visually recognized as black. Such a display device consumes little power because it does not emit light.

JP 2004-125962 A Japanese Patent Laid-Open No. 2004-127661 Japanese Patent Laid-Open No. 2003-140114 JP 2003-98541 A

  The above-described type of display device with light emission has rich gradation expression and high drawing speed, but consumes power because the backlight member and the element itself emit light. On the other hand, a type of display device that uses external light consumes little power to maintain the display state, but the drawing speed is slow because it takes time to switch between the transmissive state and the reflective state. Therefore, a display device that performs drawing in a short time while reducing power consumption is desired.

A display device according to a first aspect of the present invention includes a first display element that performs display by controlling the amount of light emitted for each pixel in accordance with an image signal, and the first display element, and displays the image signal. Accordingly, a second display element that performs display by controlling the light transmission state and the reflection state for each pixel, and (1) directs drawing to the first display element, and at least a drawing area by the first display element The second display element is instructed to make the pixel of the second display element corresponding to the transmissive state, and (2) the second display element has the same contents as the first display element except for the display color. To the first display element so that the pixels of the first display element corresponding to the drawing area by the second display element are drawn in a predetermined color in synchronization with the drawing speed by the second display element. (3) after drawing by the second display element, at least Characterized in that it comprises a display control means for stopping display control for the display device.
According to a second aspect of the present invention, there is provided a display device comprising: a first display element that performs display by controlling a light emission amount for each pixel according to an image signal; Accordingly, a second display element that performs display by controlling the light transmission state and the reflection state for each pixel, and (1) directs drawing to the first display element, and at least a drawing area by the first display element The second display element is instructed to make the pixel of the second display element corresponding to the transmissive state, (2) the second display element is instructed to draw the same content as the first display element, ( 3) A display control means for stopping display control for at least the first display element after drawing by the second display element is provided.
3. The display device according to claim 1, wherein the first display element may be configured as an active drive type, and the second display element may be configured as a passive drive type. It may be slower than the drawing speed of one display element.
The display device according to the third aspect may further include an illumination unit that illuminates the first display element, and the stop of the display control in this case may include turning off the illumination unit.
In the display device according to claim 3, the first display element may be configured to be a self-luminous type, and the stop of the display control in this case may include a stop of power supply to the first display element.
The display device according to any one of claims 3 to 5,
The second display element can also maintain the transmission and reflection states controlled for each pixel even after the power supply is stopped.

  In the display device according to the present invention, the first display element that controls the light emission amount for each pixel according to the image signal, and the second display element that controls the light transmission state and the reflection state for each pixel according to the image signal. The second display element is stacked so as to instruct the first display element to perform drawing, and at least the pixels of the second display element corresponding to the drawing area of the first display element are in a transmissive state. The second display element is instructed to draw the same content as the first display element, and the pixels of the first display element corresponding to the drawing area by the second display element are drawn in a predetermined color. Since the first display element is instructed to stop the display control for at least the first display element after the drawing by the second display element is finished, the high-speed drawing characteristics and the first display element by the first display element are stopped. Display protection by 2 display elements Characteristics and are properly utilized, while suppressing the power consumption, can be drawn in a short time.

  The best mode for carrying out the present invention will be described below with reference to the drawings. As shown in FIG. 13, a display device 100 according to an embodiment of the present invention is mounted on an electronic device such as a PDA 200 or a mobile phone (not shown), a digital camera, or an electronic book viewer.

  1 and 2 are diagrams for explaining the configuration of the display device 100. FIG. 1 is a front view and FIG. 2 is a side view. In FIG. 1, the display device 100 displays an image, text, etc. in an effective display area 100a.

  In FIG. 2, the display device 100 is configured by laminating a first display module 10 and a second display module 20. The two stacked display modules 10 and 20 are illuminated from the first display module 10 side by the backlight member. The backlight member includes a high-intensity white LED 141, an LED substrate 142 on which the white LED 141 is mounted, and the light guide plate 14. The light guide plate 14 has a larger area than at least the effective display area 100a. The light guide plate 14 is emitted from the white LED 141, and light incident on the light guide plate 14 from the side surface (right in FIGS. 1 and 2) of the light guide plate 14 is converted into surface illumination light having a uniform luminance within the effective display area 100a. Then, the first display module 10 is illuminated with the surface illumination light. The observer observes the display image from above in FIG.

  Display data, drive signals, and the like are supplied to the first display module 10 and the second display module 20 from flexible display boards 150 and 151 from a display control circuit described later.

  FIG. 3 is an enlarged view of a part of FIG. 2 for explaining the internal structure of the display device 100. In FIG. 3, the first display module 10 is constituted by, for example, a well-known TFT type liquid crystal panel. The liquid crystal 11 is sealed between the two glass substrates 12a and 12b, and the first polarizing plate 13a and the second polarizing plate 13b are disposed so as to sandwich the glass substrates 12a and 12b. Here, the polarization direction of the light passing through the second polarizing plate 13b is different from the polarization direction of the light passing through the first polarizing plate 13a by 90 degrees. A color filter (not shown) is disposed between the glass substrate 12b and the second polarizing plate 13b.

  In a state where no voltage is applied from a transparent electrode (not shown) provided inside the glass substrate 12, the liquid crystal 11 is incident on the liquid crystal layer due to the arrangement (orientation) of liquid crystal molecules in the liquid crystal layer. The polarization direction is rotated 90 degrees. As a result, the polarized light incident on the liquid crystal 11 through the first polarizing plate 13a is rotated by 90 degrees in the liquid crystal layer, and then passes through the second polarizing plate 13b from the first display module 10. It is emitted and incident on the second display module 20.

  On the other hand, in the liquid crystal 11 to which a voltage is applied from a transparent electrode (not shown), the arrangement of the liquid crystal molecules in the liquid crystal layer changes and the polarization direction of incident light is not rotated by 90 degrees. Thereby, since the polarized light incident on the liquid crystal 11 through the first polarizing plate 13a cannot pass through the second polarizing plate 13b, the amount of transmitted light emitted from the first display module 10 is reduced. Since the change in the alignment of the liquid crystal molecules is proportional to the applied voltage, the rotation ratio of the polarization direction of light traveling through the liquid crystal layer is also proportional to the applied voltage. Therefore, the amount of light that passes through the first display module 10 and enters the second display module 20 decreases as the voltage applied to the liquid crystal 11 increases.

  The liquid crystal 11 is configured to be able to apply an arbitrary voltage corresponding to a drive signal supplied from a display control circuit (described later) to each predetermined region (pixel) divided in a matrix based on an image signal. . As a result, the optical image generated by the first display module 10 based on the image signal is incident on the second display module 20. In this display method, since the transmittance of illumination light, in other words, the amount of modulated light emitted can be controlled arbitrarily for each pixel, rich gradation expression is possible. Furthermore, since the color filter is transmitted as described above, it is suitable for full color display of photographic images and moving images.

  The second display module 20 includes a liquid crystal panel in which a cholesteric liquid crystal 21 is sealed between two glass substrates 22a and 22b. The cholesteric liquid crystal 21 is configured to be able to apply an arbitrary voltage corresponding to a drive signal supplied from a display control circuit (described later) based on an image signal for each predetermined region (pixel) divided in a matrix. . The liquid crystal 21 to which a voltage is applied from the transparent electrode switches between a transmission state and a reflection state.

  The pixel in the reflective state diffuses and reflects external light and is visually recognized by the observer as yellow, for example. The pixel in the transmissive state transmits the light image generated by the first display module 10, and the observer visually recognizes the color image displayed by the first display module 10. Since the cholesteric liquid crystal has a memory property, the reflection state (or transmission state) is maintained even when the power supply to the second display module 20 is cut off.

  The effective display area 100a of the display device 100 corresponds to the effective display area of the first display module 10, and the effective display area of the second display module 20 is configured to be at least wider than the effective display area 100a. The light guide plate 14, the first display module 10, and the second display module 20 described above are superposed so as to be in close contact with each other, and constitute the display device 100.

  FIG. 4 is a control block diagram of the display device 100. The battery BT supplies power to each block including the CPU 31. The first display module 10 is driven and controlled by the display control circuit 32. The display control circuit 32 includes a liquid crystal drive circuit 32a that drives the liquid crystal 11 via a transparent electrode, and a backlight control unit 32b that controls lighting of the white LED 141. On the other hand, the second display module 20 is driven and controlled by the display control circuit 33. The display control circuit 33 drives the liquid crystal 21 through the transparent electrode. The CPU 31 transmits a liquid crystal drive command together with display data to the display control circuits 32 and 33, and reads and writes image data and character data with respect to the image storage device 34 and the recording medium 37. The brightness sensor 35 detects the brightness around the display device 100 and outputs a detection signal to the CPU 31. The clock circuit 36 divides the clock signal to generate time information. The image storage device 34 is constituted by, for example, a hard disk device. The recording medium 37 is constituted by, for example, a removable memory card.

A display mode by the display device 100 configured as described above will be described.
(Image display)
When displaying a reproduced image based on image data recorded in the image storage device 34 or the storage medium 37 on the display device 100, the white LED 141 is turned on and the reproduced image is displayed on the first display module 10 as shown in FIG. On the other hand, the second display module 20 makes all the pixels transparent (transparent) state. The observer observes the display image formed by the display light emitted from the first display module 10 through the second display module 20 in the transmissive state. Here, when the second display module 20 has a display memory property (the state is maintained even when power supply is cut off), all the pixels are set in a transmissive state with respect to the second display module 20. After switching, power supply is cut off and the state is maintained. Thereby, when displaying a still image on the display device 100, all the pixels of the second display module are set in the transmission (transparent) state, and the image display can be continued only by supplying power to the first display module 10.

(Character display)
On the other hand, when displaying a character etc. on the display apparatus 100, as shown in FIG. 6, the area | region (pixel) corresponding to the character which the 2nd display module 20 wants to display is made into a transparent state, and other area | regions (pixel) are shown. While being in a reflective state, the driving of the liquid crystal 11 is stopped with respect to the first display module 10, the power supply is further cut off, and the LED 141 is turned off. Since all the pixels of the first display module 10 are in a non-emission state, that is, blackened by turning off the power supply, the light transmitted through the transmission region (character portion) of the second display module 20 is absorbed by the blackened portion. . As a result, the black character displayed on the yellow background is visually recognized by the observer. Since the first display module 10 in the power-off state also serves as an absorption layer necessary for the second display module 20, it is not necessary to separately provide a black plate or the like constituting the absorption layer. Contrary to the above, the area (pixel) corresponding to the character to be displayed on the second display module 20 is set in the reflective state, the other area (pixel) is set in the transmissive state, the LED 141 is turned off, and the first If all the pixels of the display module 10 are blackened in a non-injection state, yellow characters are visually recognized on a black background.

  As described above, since the second display module 20 maintains the transmission state or the reflection state even after the power supply is cut off, the first display module 10 and the second display module 20 are not updated when the display contents are not updated. Power supply to both sides can be turned off to minimize power consumption.

(Mixed display)
When an image is displayed on a part of the effective display area 100a of the display device 100 and a character is displayed on another part, for example, the image is displayed on the upper half of the first display module 10 as shown in FIG. Then, the lower half is displayed in black and the white LED 141 is lit. On the other hand, for the second display module 20, the upper half is in the transparent state, the area (pixel) corresponding to the lower half character is in the transparent state, and the area (pixel) other than the lower half character is in the reflective state. To. Thereby, the observer can observe the reproduction display image by the first display module 10 in the upper half of the screen through the transmission area of the second display module 20, and the display by the second display module 20 in the lower half of the screen. Characters (black characters on yellow background) can be observed.

  Note that if the first display module 10 is configured using a self-luminous element such as an organic EL, the power supply to the lower half of the first display module 10 can be turned off, and the first display module alone is the same. The power consumption in the first display module 10 can be reduced to half compared to the case of performing the display. In the mixed display, the mixing ratio of the image display area and the character display area, the number, position, size, and the like of each area may be arbitrarily changed.

(Character color display)
For example, when displaying a character in red on the display device 100, as shown in FIG. 8, the region (pixel) corresponding to the character of the second display module 20 is in a transparent state, and the region (pixel) corresponding to a character other than the character. To the reflective state. In the first display module 10, the area corresponding to the character (or a predetermined area including the area corresponding to the character) is displayed in red, the other areas are displayed in black, and the white LED 141 is lit. Thereby, the observer can visually recognize the red color of the first display module 10 through the transmission region (character pixel) of the second display module 20. That is, the display device 100 displays red characters on a yellow background.

  In addition, if the area | region (or predetermined area | region containing the area | region corresponding to a character) of the 1st display module 10 is displayed on blue, green, etc., a character can also be displayed on colors other than red. Moreover, you may make it display changing a color for every character.

(Display module selection)
The CPU 31 is configured to automatically select which display mode of FIGS. 5 to 7 is to be displayed according to the content to be displayed. For example, when the display content is a color image such as a still image, a moving image, or an animation, the CPU 31 automatically selects the display mode illustrated in FIG. When the display content is composed of text and simple patterns, the CPU 31 automatically selects the display mode illustrated in FIG. If the display content is a mixture of images and text, the display mode illustrated in FIG. 7 is automatically selected. This eliminates the need for the observer to select the display mode, and improves the usability of the display device 100. Note that the display mode may be switched by a selection operation by an observer.

  In addition, when the display content is composed of text or simple patterns, the display mode of FIG. 6 is usually suitable as described above, but this is not the case when the periphery of the display device 100 is dark. In this case, the CPU 31 selects the display mode of FIG. 6 if the detection signal input from the brightness sensor 35 indicates a predetermined brightness or more, and the detection signal is less than the predetermined brightness. Is selected, the display mode of FIG. 5 is selected. In the display mode of FIG. 5, since the backlight (LED 141 in the above example) that illuminates the first display module 10 is turned on, the observer can observe the display contents even when the surroundings are dark.

  Instead of detecting the brightness by the brightness sensor 35, the display mode may be selected according to the time information from the clock 36. In this case, the CPU 31 selects the display mode of FIG. 6 if it is a predetermined time zone (daytime bright time zone), and selects the display mode of FIG. 5 in other time zones.

  Furthermore, using the well-known battery check function, if the remaining amount of the battery BT is greater than or equal to a predetermined value, the display mode of FIG. You may make it the structure to carry out. Thereby, the lifetime of battery BT can be extended.

  Furthermore, when the display time of the same content by the first display module 10 reaches a predetermined time, the same content display is automatically performed on the second display module 20 to save power. Also good.

  Since the first display module 10 that constitutes the display device 100 is a so-called active drive method, the drawing speed is higher than that of the passive drive method, but it is necessary to continue driving (power feeding) when holding the display contents. There is. On the other hand, since the second display module 20 is a passive drive system, the drawing speed is slower than that of the active drive system, but the display content can be retained even when the drive (power supply) is stopped.

  The present invention relates to the case where the display device 100 performs character display, that is, the display mode of FIG. 5 or 7, and the high-speed drawing characteristics by the first display module 10 and the display holding characteristics by the second display module 20. Are effectively used.

  FIG. 9 is a flowchart for explaining a drawing processing procedure performed by the CPU 31 when the display device 100 displays characters, for example. In step S1 of FIG. 9, the CPU 31 instructs the first display module 10 to perform drawing, and proceeds to step S2. Specifically, text data, a liquid crystal drive command for text display (for example, black characters), and an LED lighting command are transmitted from the CPU 31 to the display control circuit 32. Thereby, the text screen illustrated in FIG. 10A is drawn on the first display module 10.

  In step S2, the CPU 31 instructs drawing on the second display module 20, and proceeds to step S3. Specifically, a liquid crystal drive command for setting all the pixels to the transmissive state is transmitted from the CPU 31 to the display control circuit 33. As a result, the second display module 20 is brought into the entire transparent state illustrated in FIG. An observer observes the text screen by the first display module 10 through the second display module 20 in a transparent state. Note that the order of step S1 and step S2 may be reversed.

  In step S3, the CPU 31 draws on the second display module 20 (the area corresponding to the characters of the second display module 20 is a transmission area, and the other area is a reflection area, or the second display module An area corresponding to 20 characters is set as a reflection area, and the other area is set as a transmission area, and an area (pixel) on the first display module 10 corresponding to a line drawn by the second display module 10 ) Is set to a predetermined color (for example, black), and the process proceeds to step S4. Specifically, text data and a liquid crystal drive command for text display are transmitted from the CPU 31 to the display control circuit 33. The text data is common with the data transmitted to the first display module 10. As a result, text is drawn line by line on the second display module 20 as illustrated in FIG. 11B. Next, data corresponding to blackening and a liquid crystal drive command are transmitted from the CPU 31 to the display control circuit 32. As a result, the first display module 10 is drawn in black line by line in synchronization with the drawing processing speed of the second display module 20 as illustrated in FIG. 10B. The observer observes the text screen in the same manner as at the end of step S2.

  In step S4, the CPU 31 determines whether all lines have been completed. The CPU 31 makes an affirmative decision in step S4 when drawing of all lines is completed in the second display module 20 and proceeds to step S5. If all lines are not finished, the CPU 31 returns to step S3 and continues the process. Then, the determination process is repeated.

  In step S5, the CPU 31 instructs the first display module 10 to stop driving the liquid crystal, turn off the power supply, and turn off the backlight to the backlight control unit 32b, and then proceeds to step S6. Thereby, as illustrated in FIG. 10C, the first display module 10 is turned off in a state where all lines are drawn in black. In step S6, the CPU 31 instructs the second display module 20 to stop driving the liquid crystal and turn off the power supply, and ends the process of FIG. Thereby, as illustrated in FIG. 11C, the second display module 20 is turned off in a state where a text screen having the same content as in FIG. 10A is drawn. The observer observes the text screen in the same manner as at the end of step S2.

According to the embodiment described above, the following operational effects can be obtained.
(1) The display device 100 is configured by stacking the second display module 20 of the passive drive type on the first display module 10 of the active drive type, and drawing is performed on different display modules according to display contents. As a result, a variety of high-contrast display is possible, but power consumption can be minimized.

(2) At the time of updating the character display, the first display module 10 is drawn at the start of the display and the entire surface of the second display module is made transparent (steps S1 and S2), so that the second display module 20 Drawing (updating display contents) can be performed faster than if drawing is performed.

(3) At the time of updating the character display, after the drawing by the first display module 10, the same content as the drawing content by the first display module 10 is drawn on the second display module 20, and the first display module 10 , The region (pixel) corresponding to the line drawn by the second display module 10 is blackened (step S3). Thereby, the second display module 20 can be made to draw gradually the same content as the drawing content by the 1st display module 10, keeping the text screen which became observable at the time of completion | finish of step S2.

(4) When the character display is updated, the liquid crystal drive of the first display module 10 is performed in a state where all the lines of the first display module 10 are drawn in black after the drawing of all the lines by the second display module 10. In addition, the power supply was turned off (step S5), and the liquid crystal drive and power supply of the second display module 20 were turned off (step S6). As a result, the power consumption can be greatly reduced while maintaining the text screen that can be observed at the end of step S2.

  In step S5, the display control is stopped by stopping the liquid crystal drive for the first display module 10 and turning off the power supply to the first display module 10. Instead, the power supply to the first display module 10 may be continued if an instruction is given to turn off at least the white LED 141. Power consumption can be reduced by turning off the white LED 141.

  Although a text screen is illustrated as an example of character display, the present invention can also be applied to the case of displaying a still image. In the above-described embodiment, the example in which the second display module 20 displays binary characters has been described. However, a multi-value image can be displayed by changing the driving voltage or using a known dither technique. You can also.

  The present invention may also be applied when displaying a screen in which text information and still images are mixed.

(Modification)
In step S3 described above, the first display module 10 is drawn in a predetermined color for each line, but after drawing all the lines in the second display module 20, all the lines in the first display module 10 are drawn. You may draw at once. FIG. 14 is a flowchart for explaining the operation of the CPU 31 at this time. Step S1, step S2, step S5 and step S6 are the same operations as the respective steps shown in FIG. FIG. 12 is a diagram illustrating the drawing contents by the first display module 10 in this case. 12 (a) and 12 (c) are the same as FIGS. 10 (a) and 10 (c), respectively, and a description thereof will be omitted.

  While the CPU 31 in the modified example causes the second display module 20 to draw the text line by line as illustrated in FIG. 11B in step S30, as illustrated in FIG. One display module 10 holds the text screens of all lines drawn in step S1 as they are. The observer observes the text screen in the same manner as at the end of step S2.

  In step S <b> 40, the CPU 31 in the modified example determines whether or not drawing for the second display module 20 has been completed for all lines. The CPU 31 makes an affirmative decision in step S40 when drawing of all lines has been completed in the second display module 20, and proceeds to step S5. As a result, all the lines of the first display module 10 are displayed in black at once (power supply and drive off state). At this time, the display of the first display module 10 may be a predetermined color (power supply and drive-on state). On the other hand, the CPU 31 repeats the determination process when drawing of all the lines is not completed in the second display module 20.

  In the above description, the first display module 10 is configured using a TFT liquid crystal module, but an organic EL module may be used instead of the TFT liquid crystal module. Since the organic EL module emits light itself, the backlight member can be omitted. In addition, you may comprise the 1st display module 10 using an inorganic EL element.

  Further, the second display module 20 may be configured using a PN (polymer network) liquid crystal module instead of the cholesteric liquid crystal module. Since the PN liquid crystal module does not have memory characteristics, driving and power supply are required to maintain the display contents, but the display contents can be maintained with low power consumption because the backlight and the element itself do not emit light. . Further, while the color of the reflected light is yellow or reddish in the cholesteric liquid crystal, white reflected light is obtained in the PN liquid crystal, so that it is possible to display black characters on a white background or white characters on a black background.

  The correspondence between each component in the claims and each component in the best mode for carrying out the invention will be described. The first display element is constituted by, for example, the first display module 10. The second display element is configured by, for example, the second display module 20. The display control means is constituted by, for example, the CPU 31. The illumination means is constituted by, for example, the LED 141, the substrate 142, and the light guide plate 14. In addition, the above description is an example to the last, and when interpreting invention, it is not limited to the correspondence of the component of said embodiment and the component of this invention at all.

It is a front view explaining the structure of a display apparatus. It is a side view explaining the structure of a display apparatus. It is the figure which expanded a part of FIG. It is a control block diagram of a display device. It is a figure explaining an image display. It is a figure explaining a character display. It is a figure explaining mixed display. It is a figure explaining the color display of a character. It is a flowchart explaining the drawing process procedure performed by CPU. It is a figure explaining drawing by the 1st display module. It is a figure explaining drawing by the 2nd display module. It is a figure explaining drawing by the 1st display module. It is a figure which illustrates PDA carrying a display apparatus. It is a flowchart explaining the drawing process procedure performed by CPU.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... 1st display module 11, 21 ... Liquid crystal 12a, 12b, 22a, 22b ... Glass substrate 13a, 13b ... Polarizing plate 14 ... Light guide plate 20 ... 2nd display module 31 ... CPU
32, 33 ... display control circuit 100 ... display device 141 ... white LED
142 ... substrate

Claims (6)

A first display element that performs display by controlling the amount of light emitted for each pixel according to an image signal;
A second display element that is stacked with the first display element and performs display by controlling a transmission state and a reflection state of light for each pixel according to an image signal;
(1) Instructing the drawing to the first display element, and at least the second display so that the pixel of the second display element corresponding to the drawing area by the first display element is in the transmissive state Instruct the element,
(2) The second display element is instructed to draw the same content as that of the first display element except for at least the display color, and the first display element corresponding to the drawing area by the second display element Instructing the first display element to draw pixels in a predetermined color in synchronization with the drawing speed of the second display element;
(3) A display device comprising: display control means for stopping display control on at least the first display element after drawing by the second display element. A first display element that performs display by controlling the amount of light emitted for each pixel according to an image signal;
A second display element that is stacked with the first display element and performs display by controlling a transmission state and a reflection state of light for each pixel according to an image signal;
(1) Instructing the drawing to the first display element, and at least the second display so that the pixel of the second display element corresponding to the drawing area by the first display element is in the transmissive state Instruct the element,
(2) Instructing the second display element to draw the same content as the first display element;
(3) A display device comprising: display control means for stopping display control for at least the first display element after completion of drawing by the second display element. The display device according to claim 1 or 2,
The first display element is an active drive type,
The second display element is a passive drive type,
A display device, wherein a drawing speed by the second display element is slower than a drawing speed by the first display element. The display device according to claim 3,
Illuminating means for illuminating the first display element;
Stopping the display control includes turning off the illumination means. The display device according to claim 3,
The first display element is self-luminous;
Stopping the display control includes stopping power supply to the first display element. The display device according to any one of claims 3 to 5,
The display device, wherein the second display element maintains a transmission and reflection state controlled for each pixel even after power supply is stopped.

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