JP2011209363A - Display device and program for the same - Google Patents

Abstract

An object of the present invention is to provide a display device and a program for the display device that can quickly rewrite an image even after returning from a power saving state.
An image based on an image file is displayed on the non-volatile display unit, and is stored in the first storage unit before the power control unit switches from a first power state to a second power state. The raster data saving control unit for storing the raster data in the second storage unit and the power control unit stored in the second storage unit after switching from the second power state to the first power state. A raster data return control unit for storing raster data in the first storage unit.
[Selection] Figure 2

Description

  The present invention relates to a display device and a program for the display device.

  As described in Japanese Patent Application Laid-Open No. 2004-228688, a display device that preliminarily creates raster data of an image that is supposed to be displayed next and stores the data in a RAM in advance, or a display device that caches raster data of an image once displayed in the RAM It has been known. In such a display device, when the raster data is rewritten to an image already cached in the RAM, the image can be rewritten without newly creating the raster data. Therefore, the image can be rewritten promptly.

  On the other hand, a display device provided with a non-volatile display panel including an electrophoretic display element, a cholesteric liquid crystal, or the like, as in the display device described in Patent Document 2. A display device including such a nonvolatile display panel can be shifted to a power saving state in which power supply to the RAM is stopped while image display is maintained.

JP 2009-109880 A JP 2008-197953 A

  Even in a display device such as Patent Document 2, raster data of an image that is supposed to be displayed next is created in advance and stored in RAM, or raster data of an image once displayed is cached in RAM. It is valid.

  As described above, the display device including the nonvolatile display panel can shift to the power saving state in which the power supply to the RAM is stopped while the displayed image is maintained. Therefore, it is desirable that another image can be rewritten as soon as possible after returning from the power saving state, as before the transition to the power saving state. However, since the power supply to the RAM is stopped after shifting to the power saving state, the raster data in the RAM is erased. Therefore, when rewriting to an image different from that being displayed, raster data must be created anew. Therefore, it is impossible to quickly rewrite to another image after returning from the power saving state.

  Therefore, an object of the present invention is to provide a display device and a program for the display device that can quickly rewrite an image even after returning from a power saving state.

In order to solve the above-described problem, a display device according to claim 1 is provided:
A non-volatile display that maintains the display of the image even when the power supply is cut off,
An image file acquisition unit that acquires an image file that is an image data file;
Raster data created according to the image file acquired by the image file acquisition unit, storing at least one raster data of an image different from the image being displayed, and when power supply is cut off A first storage unit that is a volatile storage unit from which data is erased;
A second storage unit that is a storage unit provided separately from the first storage;
An operation unit that accepts user operations;
Power supply to the first storage unit is performed, the first power state in which the image of the nonvolatile display unit can be rewritten, and the power supply to the first storage unit is stopped, and the first power unit is stopped. A power control unit that switches between a second power state that consumes less power than the state;
The raster data stored in the first storage unit before the power control unit switches from the first power state to the second power state while the image based on the image file is displayed on the nonvolatile display unit A raster data saving control unit to be stored in the second storage unit;
After the power control unit switches from the second power state to the first power state, a raster data return control unit that stores the raster data stored in the second storage unit in the first storage unit;
When the operation unit rewrites an image and the raster data corresponding to the rewritten image is stored in the first storage unit, the raster data stored in the first storage unit is stored in the raster data stored in the first storage unit. Therefore, when the image is rewritten and raster data corresponding to the rewritten image is not stored in the first storage unit, raster data is created from the image file acquired from the image file acquisition unit, and the generated raster data And a rewrite control unit for rewriting an image according to the above.

According to the display device of claim 2, in addition to the features of the display device of claim 1,
The raster data saving control unit stores only a part of raster data among the plurality of raster data stored in the first storage unit in the second storage unit.

According to the display device of claim 3, in addition to the features of the display device of claim 1,
When there is raster data stored in the second storage unit at the time of switching to the second power state last time,
In the period from the switching from the second power state to the first power state until the start of operation acceptance by the operation unit, the last stored raster data is not deleted,
Before the raster data save control unit stores the raster data in the second storage unit, the raster data save control unit includes a raster data deletion control unit that deletes the previously stored raster data.

According to the display device of claim 4, in addition to the features of the display device of claim 1,
The raster data saving control unit causes the second storage unit to store only the number of raster data that fits in a predetermined capacity among a plurality of raster data stored in the first storage unit. And

Further, according to the display device of claim 5, in addition to the features of the display device of claim 1,
A notification unit for notifying the user that the power state has been switched to the second power state;
The raster data evacuation control unit stores the raster data stored in the first storage unit in the second storage unit after notifying that the notification unit has switched to the second power state. And

Further, according to the display device according to claim 6, in addition to the features of the display device according to claim 5,
After notifying the switching to the second power state by the notification unit, when the operation to switch to the first power state is received by the operation unit, the raster data saving control unit stores in the first storage unit The storage of the raster data thus made is stopped in the second storage unit.

According to the display device program of claim 7,
A non-volatile display that maintains the display of the image even when the power supply is cut off,
An image file acquisition unit that acquires an image file that is an image data file;
Raster data created according to the image file acquired by the image file acquisition unit, storing at least one raster data of an image different from the image being displayed, and when power supply is cut off A first storage unit that is a volatile storage unit from which data is erased;
A second storage unit that is a storage unit provided separately from the first storage;
An operation unit that accepts user operations;
Power supply to the first storage unit is performed, the first power state in which the image of the nonvolatile display unit can be rewritten, and the power supply to the first storage unit is stopped, and the first power unit is stopped. A power control unit that switches between a second power state that consumes less power than the state;
The raster data stored in the first storage unit before the power control unit switches from the first power state to the second power state while the image based on the image file is displayed on the nonvolatile display unit Raster data saving step to be stored in the second storage unit;
After the power control unit switches from the second power state to the first power state, a raster data return step for storing the raster data stored in the second storage unit in the first storage unit;
When the operation unit rewrites an image and the raster data corresponding to the rewritten image is stored in the first storage unit, the raster data stored in the first storage unit is stored in the raster data stored in the first storage unit. Therefore, when the image is rewritten and raster data corresponding to the rewritten image is not stored in the first storage unit, raster data is created from the image file acquired from the image file acquisition unit, and the generated raster data And a rewriting step of rewriting the image according to the above.

  According to the first and seventh aspects of the invention, it is possible to quickly rewrite an image after switching from the second power state to the first power state.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the raster data save control unit stores only a part of the raster data in the second storage unit. Transition from one power state to the second power state can be performed quickly.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1, the acceptance of the operation by the operation unit is started from the switching from the second power state to the first power state. In the meantime, since the previously stored raster data is not deleted, the user's operation can be promptly accepted after switching to the first power state.

  According to a fourth aspect of the present invention, in addition to the effect of the first aspect of the invention, the raster data saving control unit only applies the number of raster data that can be accommodated in a predetermined capacity. Since the data is stored in the second storage unit, the raster data does not occupy the capacity of the second storage unit more than necessary.

  Further, according to the invention described in claim 5, after the raster data stored in the first storage unit is stored in the second storage unit, the notification of switching to the second power state is stored. However, since the raster data stored in the first storage unit is performed before the second storage unit is stored, the time for the user to wait in front of the display device can be shortened.

  According to the invention described in claim 6, when the user performs an operation of switching to the first power state, the raster data stored in the first storage unit is stored in the second storage unit. Can be canceled.

1 is a schematic diagram showing an appearance of a display device 100. FIG. 3 is a block diagram showing a hardware configuration of display device 100. FIG. 3 is a schematic diagram showing a storage area provided in a RAM 52. FIG. 3 is a schematic diagram showing a storage area provided in an internal memory 104. FIG. It is the flowchart which showed the flow of the main process. It is the flowchart which showed the flow of the initial process. It is the flowchart which showed the flow of the key input monitoring process. It is the flowchart which showed the flow of the document selection process. It is the flowchart which showed the flow of the prefetch process. It is the flowchart which showed the flow of the document display process. It is the flowchart which showed the flow of the next key pressing process. It is the flowchart which showed the flow of the front key pressing process. It is the flowchart which showed the flow of the close key press process. It is the flowchart which showed the flow of the power-off process.

  The display device 100 to which the present invention is applied will be described below. As shown in FIG. 1, the display device 100 includes a nonvolatile display panel 103, an operation unit 105, and an LED display unit 111. The display device 100 rewrites the image on the non-volatile display panel 103 in accordance with a user operation.

  The non-volatile display panel 103 displays various images such as a document displayed according to a document file in a predetermined format and a document selection screen for selecting a document to be displayed.

  As the nonvolatile display panel 103, a display panel including an electrophoretic display element, a cholesteric liquid crystal, or the like can be used. In the following description, the nonvolatile display panel 103 in the present embodiment will be described as a display panel including an electrophoretic display element.

  The image of the non-volatile display panel 103 is rewritten by a display controller 102 (see FIG. 2) described later. The image displayed on the non-volatile display panel 103 is kept displayed even when power supply to the non-volatile display panel 103 or the display controller 102 is cut off. The display device 100 can suppress power consumption by stopping the supply of power to the nonvolatile display panel 103 and the display controller 102 after rewriting the image. Therefore, power consumption is less than that of a display device having a self-luminous display panel such as a conventional LCD (Liquid Crystal Display) panel or a PDP (Plasma Display Panel) that consumes power to maintain image display. There is a feature.

  The operation unit 105 includes a power key 151 that is pressed when the user instructs to turn on or off the power, and a plurality of keys for the user to input predetermined instructions while the display device 100 is turned on. And an operation key 158. The display device 100 includes a close key 153, a next key 155, a previous key 156, and 13 selection keys 157 as operation keys 158.

  The LED display unit 111 includes LEDs of three colors of blue, yellow, and red. When an invalid operation is performed by the user, the display device 100 blinks the red LED of the LED display unit 111 to notify the user of an error.

<Description of Outline of Operation of Display Device 100>
When an operation for turning off the power is performed while the document is displayed, the display device 100 shifts to a power-off state while the document is displayed on the nonvolatile display panel 103. At this time, if there is raster data cached in advance, the display device 100 saves the raster data in a nonvolatile storage device.

  When the display device 100 is in a power-off state while displaying a document, when the user presses the power key 151, the display device 100 returns to a power-on state. At this time, the display device 100 reads the raster data saved in the nonvolatile storage device. When the user performs an operation to rewrite the image after the power is turned back on, if there is raster data of the rewritten image in the read raster data, it is based on the raster data. To rewrite the image. For this reason, it is not necessary to newly create raster data from the image file, so that the image can be rewritten promptly.

  When the display device 100 shifts to a power-off state while displaying a document, the display device 100 displays a message for notifying the power-off in a part of a display area such as a margin portion of the document being displayed, Transition to the off state. Thereby, even when the display device 100 is in a power-off state, the user can continue to view a document and can know that the display device 100 is in a power-off state. As an example of the message for notifying that the power is off, a message such as “powering off” can be given.

  On the other hand, when an operation to turn off the power is performed while the document selection screen is displayed, the display device 100 rewrites the display on the non-volatile display panel 103 with a blank sheet and then shifts to a power-off state. Thereby, the user can know that the display device 100 is in a power-off state. In this case, since the document selection screen is displayed when the power is returned to the on state, the display device 100 does not save the raster data of the predetermined document in the nonvolatile storage device.

<Description of hardware configuration>
Next, the hardware configuration of the display device 100 will be described with reference to FIG. The display device 100 includes a control unit 101, a display controller 102, a nonvolatile display panel 103, an internal memory 104, an operation unit 105, a memory card interface 106, a memory card 107, an LED display unit 111, power And a control unit 112.

  The control unit 101 includes a CPU 51, a RAM 52, and a ROM 53. The CPU 51, the RAM 52, and the ROM 53 cooperate to execute each process described later and control the display device 100.

  The CPU 51 controls each peripheral device of the display device 100 according to the firmware stored in the ROM 53. In the present embodiment, the peripheral device of the display device 100 is described as being controlled by firmware stored in the ROM 53, but may be controlled by the OS and application program.

  The RAM 52 is a volatile storage device that temporarily stores a program stored in the ROM 53 when the control unit 101 executes processing and data necessary for executing each processing.

  The ROM 53 is a non-volatile storage device that stores programs such as firmware.

  The internal memory 104 is a non-volatile storage device such as a NAND flash memory. The display device 100 saves the data stored in the RAM 52 in the internal memory 104 before the power is turned off.

  The operation unit 105 includes the power key 151 and a plurality of operation keys 158 as described above. The operation unit 105 outputs a signal corresponding to the pressed operation key 158 to the control unit 101 via the key port. As a result, the control unit 101 can determine which key has been operated by the user.

  The memory card interface 106 reads data from the memory card 107 mounted on the display device 100, writes data to the memory card 107, erases data from the memory card 107, and the like in accordance with instructions from the control unit 101.

  The memory card 107 stores a document file in a predetermined format that can be displayed on the display device 100. The memory card 107 is detachably attached to the display device 100. The document file stored in the memory card 107 includes a plurality of pages of image data.

  The non-volatile display panel 103 in this embodiment is a known active matrix type electrophoretic display panel. The nonvolatile display panel 103 includes a transparent substrate on the display surface side and a back substrate provided at a position facing the transparent substrate. An electrophoretic display element is provided between the transparent substrate and the back substrate. The nonvolatile display panel 103 includes a gate driver (not shown) for outputting a gate signal to each gate line of the nonvolatile display panel 103, and a source for outputting a source signal to each source line of the nonvolatile display panel 103. A driver (not shown).

  The display controller 102 executes an image rewriting operation by controlling the output of the gate signal by the gate driver and the output of the source signal by the source driver. In accordance with the image rewriting instruction received from the CPU 51, the display controller 102 outputs an instruction to output a gate signal and a source signal corresponding to the image to be rewritten to the gate driver and the source driver. As a result, a drive voltage for controlling the electrophoretic display element is applied to each pixel electrode of the nonvolatile display panel 103, and the image displayed on the nonvolatile display panel 103 is rewritten.

  The power control unit 112 is connected to a power source not shown. The power control unit 112 is supplied from the power source with the CPU 51 and peripheral devices (CPU 51, RAM 52, ROM 53, display controller 102, nonvolatile display panel 103, internal memory 104, operation unit 105, memory card interface 106 constituting the display device 100. The power supply to the LED display unit 111) is controlled. Further, the power control unit 112 stops the power supply to the nonvolatile display unit 120 in accordance with an instruction from the CPU 51 except when the image is rewritten. As a result, it is possible to prevent power from being consumed by the load of the non-volatile display unit 120 other than during image rewriting. In addition, what is necessary is just to use secondary batteries, such as a lithium ion secondary battery, as a power supply.

  The LED display unit 111 includes LEDs corresponding to the respective colors of blue, yellow, and red, and in accordance with an instruction from the CPU 51, blinks the LED of the color corresponding to the instruction.

  Next, a storage area provided in the RAM 52 during execution of the program of the display device 100 will be described with reference to FIG. As shown in FIG. 3, the RAM 52 includes a page cache storage area 201, an image type storage area 202, a displayed document name storage area 203, a page configuration storage area 204, a displayed page number storage area 205, and a key buffer storage. Region 206.

  The page cache storage area 201 stores raster data created based on a document file acquired from the memory card 107 via the memory card interface 106.

  The image type storage area 202 stores data indicating the type of image being displayed on the display device 100. For example, when a document selection screen is displayed on the display device 100, “document selection” is stored. Further, when a predetermined document is displayed on the display device 100, “document” is stored.

  In the displayed document name storage area 203, data indicating the document name of the document being displayed on the display device 100 is stored. For example, when a document titled “Document A” is displayed on the display device 100, “Document A” is stored in the displayed document name storage area 203. If the image being displayed is a document selection image, a NULL value is stored.

  The page configuration storage area 204 stores data indicating the total number of pages of the document being displayed on the display device 100. For example, when a 15-page document is being displayed, “15” indicating that is stored. If the displayed image is a document selection screen, a NULL value is stored.

  The displayed page number storage area 205 stores data indicating what page of the document being displayed by the display device 100 is being displayed. For example, when the display device 100 is displaying an image of the fifth page of a document consisting of 15 pages, “5” is stored. If the displayed image is a document selection screen, a NULL value is stored.

  The RAM 52 has a work area (not shown) for temporarily storing other data and the like in addition to the above-described storage area.

  Next, a storage area provided in the internal memory 104 will be described with reference to FIG. As shown in FIG. 4, the internal memory 104 includes a page cache save area 301, a displayed document name save area 302, a page configuration save area 303, and a displayed page number save area 304.

  The page cache save area 301 is an area in which raster data stored in the page cache storage area 201 before the display device 100 is turned off is stored.

  The displayed document name saving area 302 is an area in which data stored in the displayed document name storage area 203 before the display device 100 is turned off is stored. For example, when the power of the display device 100 is turned off while a document titled “Document A” is displayed, “Document A” is stored in the displayed document name saving area 302.

  The page configuration save area 303 is an area in which data stored in the page configuration storage area 204 before the display device 100 is turned off is stored. For example, when a document consisting of 15 pages is displayed and the display device 100 is turned off, “15” is stored in the page configuration save area 303.

  The displayed page number saving area 304 is an area in which data stored in the displayed page number storage area 205 before the display device 100 is turned off is stored. For example, when the display device 100 is turned off while the fifth page of a 15-page document is displayed, “5” is stored in the displayed page number saving area 304.

<Description of Operation of Display Device 100>
The detailed operation of the display device 100 will be described using a flowchart. When the power key 151 is pressed, power supply from the power source to the control unit 101 is started, and the control unit 101 starts the main process shown in FIG.

  When the main process is started, the control unit 101 performs an initial process (step 101, hereinafter, step is referred to as S).

  Here, the initial process performed in S101 of the main process will be described with reference to FIG. When the initial process is started, the control unit 101 starts a key input monitoring process (S131). The key input monitoring process is a process performed by the control unit 101 in parallel with the main process. Although details will be described later, in the key input monitoring process, the operation of the operation key 158 by the user is monitored. The control unit 101 periodically confirms the input of the key port and confirms whether or not the operation key 158 has been pressed by the user. When the operation key 158 is pressed, key identification data for identifying the pressed operation key 158 is stored in the key buffer 206. Thereby, the control part 101 can detect a user's operation.

  After the key input monitoring process is started in S131, the control unit 101 reads the data saved in the internal memory 104 when the power is turned off to the RAM 52 (S132). Specifically, the displayed document name stored in the displayed document name saving area 302 is read out and stored in the displayed document name storage area 203. Further, the total number of pages stored in the page configuration save area 303 is read out and stored in the page configuration storage area 204. Further, the displayed page number stored in the displayed page number saving area 304 is read and stored in the displayed page number storage area 205. If the image displayed when the power is turned off the last time is a document selection screen, the displayed document name saving area 302, the page configuration saving area 303, and the displayed page number saving area 304 are set to NULL. The value will be stored. If the acquired data is a NULL value, the NULL value is also stored in the displayed document name storage area 203, the page configuration storage area 204, and the displayed page number storage area 205, respectively.

  After reading data from the internal memory 104 to the RAM 52 in S132, the control unit 101 displays a document on the non-volatile display panel 103 based on whether or not the displayed document name is stored in the displayed document name storage area 203. It is determined whether it has been performed (S133). When the display device 100 displays a document when the power is turned off the last time, the displayed document name storage area 203 stores the displayed document name, and the nonvolatile display panel 103 stores the document with the document name and the “power supply”. "Off" message is displayed. On the other hand, when the display device 100 displays the document selection screen when the power is turned off the last time, the NULL value is stored in the displayed document name storage area 203, and a blank sheet is displayed on the nonvolatile display panel 103. Yes.

  If it is determined that the displayed document name is stored (S133: Yes), the control unit 101 transmits an instruction to delete the “powering off” message to the display controller 102 (S134). The display controller 102 that has received the instruction to erase the “power off” message erases the “power off” message on the nonvolatile display panel 103 in accordance with the instruction.

  In S134, after the message “Power OFF” is deleted, the raster data stored in the page cache save area 301 of the internal memory 104 is stored in the page cache storage area 201 of the RAM 52 (S135). When raster data for a plurality of pages is stored in the page cache save area 301, raster data for the plurality of pages is acquired and stored in the page cache storage area 201. As a result, the display device 100 can rewrite the page without creating raster data from the document file.

  After storing the raster data in the page cache storage area 201, the control unit 101 stores “document” in the document type storage area 202 (S136), and proceeds to S102 of the main process.

  When the document name is not stored in the displayed document name storage area 203, that is, when a NULL value is stored in the displayed document name storage area 203 (133: No), a blank page is displayed on the nonvolatile display panel 103. Therefore, the control unit 101 rewrites the display on the non-volatile display panel 103 to a document selection screen (S137).

  After rewriting the document selection screen, the control unit 101 stores “document selection” in the screen type storage area 202 (S138), and proceeds to S102 of the main process.

  Next, referring to FIG. 5 again, the operation by the main processing after S102 will be described. After performing the initial process in S101, the control unit 101 determines whether or not key identification data is stored in the key buffer storage area 206 (S102). In the key input monitoring process described later, key identification data is stored in the key buffer storage area 206.

  When the key identification data is not stored, the control unit 101 waits until the key identification data is stored (S102: No).

  When the key identification data is stored, that is, when any operation key 105 is pressed by the user (S102: Yes), the control unit 101 stores the key identification data stored in the key buffer storage area 206. Are stored in the work area of the RAM 52, and the key identification data stored in the key buffer storage area 205 is deleted (S103).

  Next, the control unit 101 determines whether or not the key identification data stored in the work area of the RAM 52 is a “power key” (S104). When the key identification data is “power key”, the power key 151 is pressed by the user.

  When the key identification data is “power key” (S104: Yes), the control unit 101 performs a power-off process described later (S105). The power-off process is a process for saving predetermined data stored in the RAM 52 to the internal memory 104. After performing the power-off process, the control unit 101 instructs the power control unit 112 to stop supplying power to the peripheral devices including the RAM 52 (S109), and the main process ends.

  When the key identification data is not “power key” (S104: No), the control unit 101 determines whether the data stored in the image type storage area 202 is “document” (S106). When a predetermined document is displayed on the non-volatile display panel 103, “document” is stored in the image type storage area 202.

  When the data stored in the image type storage area 202 is “document” (S106: Yes), the control unit 101 performs a document display process described later (S107), and returns to S102 described above.

  When the data stored in the image type storage area 202 is not “document”, that is, when the data stored in the image type storage area 202 is “document selection” (S106: No), the control unit 101 A document selection process described later is performed (S108), and the process returns to S102.

  Although details will be described later, in S105 described above, the raster data stored in the page cache storage area 201 is stored in the page cache save area 301 before the power is turned off. When the display device 100 is turned on again, the display device 100 can rewrite the image based on the raster data saved in the page cache save area 301.

  The key input monitoring process started in S101 of the main process will be described with reference to FIG. When the key input monitoring process is started, the control unit 101 confirms the key port and determines whether any of the operation keys 158 is pressed by the user (S151).

  If it is determined that the operation key 158 has not been pressed by the user (S151: No), the control unit 101 waits 20 milliseconds (S153), and then returns to S151. The 20-millisecond standby is performed according to a known timer provided in the control unit 101.

  If it is determined that the user presses the operation key 158 (S151: Yes), the key identification data in the key buffer storage area 206 is updated (S152), and the process proceeds to S153. In the present embodiment, the key buffer storage area 206 stores one key identification data. The control unit 101 stores key identification data corresponding to the type of the operation key 158 pressed by the user. Thus, the control unit 101 can determine which operation key 158 is pressed by the user in the main process.

  Next, the document selection process performed in S108 of the main process will be described with reference to FIG. The power-off process performed in S105 of the main process and the document display process performed in S107 will be described later. The document selection process is a process performed when the display device 100 is displaying a document selection screen.

  When the document selection process is started, the control unit 101 determines whether or not the key identification data acquired from the key buffer storage area 206 is key identification data corresponding to one of the selection keys 157 (S171).

  If an operation key 158 other than the selection key 157 is pressed (S171: No), the control unit 101 sends an instruction to cause the LED display unit 111 to blink an error (S177), and returns to 102 of the main process. The LED display unit 111 that has received the error blink instruction blinks the red LED.

  If any of the selection keys 157 is pressed (S171: Yes), the control unit 101 creates raster data for the first page of the document corresponding to the pressed selection key 157 (S172). The document selection screen is a screen in which document titles are arranged at positions corresponding to the 13 selection keys 157, respectively. The user can display a desired document on the display device 100 by pressing a selection key 157 at a position corresponding to the title of the document to be displayed. The control unit 101 creates raster data for the first page of the document selected by the user based on the document file stored in the memory card 107.

  Next, the control unit 101 rewrites the display on the non-volatile display panel 103 to the image of the first page of the document based on the raster data created in S172 (S173).

  After rewriting the image, the control unit 101 stores the raster data created in S172 in the page cache storage area 201 (S174). The page cache storage area 201 stores raster data for 5 pages, for example. When the raster data for five pages has already been stored, the control unit 101 deletes the raster data of the page farthest from the currently displayed page and stores the newly created raster data.

  After updating the page cache area 201, the control unit 101 updates the data stored in the image type storage area 202, the displayed document name storage area 203, the page configuration storage area 204, and the displayed page number storage area 205 ( S176). For example, when the user selects a document consisting of all five pages titled “Document B”, the control unit 101 displays “Document” in the image type storage area 202 and “Document B” in the displayed document name storage area 203. “5” is stored in the page configuration storage area 204, and “1” is stored in the displayed page number storage area 205.

  After updating the data, the control unit 101 starts a prefetch process described later (S176), and returns to S102 of the main process. Although details of the prefetch process will be described later, this is a process of storing raster data for each page before and after the displayed page in the page cache storage area 201. The prefetch process is a process performed by the control unit 101 in parallel with the main process.

  Next, with reference to FIG. 9, the prefetching process started in S176 will be described. When the prefetch process is started, the control unit 101 determines whether there is a next page of the page being displayed (S201). The control unit 101 makes a determination based on the page number data stored in the displayed page number storage area 205 and the total page number data stored in the page configuration storage area 204.

  When determining that there is no next page (S201: No), the control unit 101 proceeds to S204 described later. When it is determined that there is a next page (S201: Yes), the control unit 101 determines whether raster data of the next page is stored in the page cache storage area 201 (S202).

  If it is determined that the raster data of the next page is stored (S202: Yes), the control unit 101 proceeds to S204 described later. If it is determined that the raster data for the next page is not stored (S202: No), the control unit 101 creates raster data for the next page based on the document file stored in the memory card 107, and the page cache. Store in the storage area 201 (S203). If raster data for five pages has already been stored, the raster data of the page farthest from the currently displayed page is deleted, and newly created raster data is stored.

  Thereafter, in S204, the control unit 101 determines whether there is a previous page of the page being displayed (S204). The control unit 101 determines whether there is a previous page based on the page number stored in the displayed page number storage area 205. For example, when the displayed page is the first page, it is determined that there is no previous page.

  If it is determined that there is no previous page (S204: No), the process returns to S102 of the main process.

  If it is determined that there is a previous page (S204: Yes), the control unit 101 determines whether raster data for the previous page is stored in the page cache storage area 201 (S205).

  When it is determined that the raster data of the previous page is stored (S205: Yes), the control unit 101 proceeds to S102 of the main process. When it is determined that the previous page raster data is not stored (S205: No), the control unit 101 creates the previous page raster data based on the document file stored in the memory card 107, and performs page cache. The data is stored in the storage area 201 (S206), and the process returns to S102 of the main process. If raster data for five pages has already been stored, the raster data of the page farthest from the currently displayed page is deleted, and newly created raster data is stored.

  Next, the document display process performed by the control unit 101 in S107 of the main process will be described with reference to FIG.

  When the document display process is started, the control unit 101 determines whether or not the key identification data stored in the key buffer storage area 206 indicates the next key 155 (S221).

  If the key identification data indicates the next key 155 (S221: Yes), the next key pressing process described later is performed (S222), and the process returns to S102 of the main process.

  If the key identification data does not indicate the next key 155 (S221: No), it is determined whether or not the key identification data stored in the key buffer storage area 206 indicates the previous key 156 (S223). ).

  If the key identification data indicates the previous key 156 (S223: Yes), a previous key pressing process described later is performed (S224), and the process returns to S102 of the main process.

  If the key identification data does not indicate the previous key 156 (S223: No), it is determined whether or not the key identification data stored in the key buffer storage area 206 indicates the key 153 to be closed (S225). ).

  When the key identification data indicates the close key 153 (S225: Yes), a close key pressing process described later is performed (S226), and the process returns to S102 of the main process.

  If the key identification data does not indicate the closing key 153 (S225: No), the LED display unit 111 is caused to blink an error (S227), and the process returns to S102 of the main process.

  Next, the next key pressing process performed in S222 of the document display process will be described with reference to FIG. When the next key pressing process is started, the control unit 101 determines whether there is a page next to the currently displayed page (S241). Based on the page number stored in the displayed page number storage area 205 and the total number of pages stored in the page configuration storage area 204, the control unit 101 determines whether there is a page next to the displayed page. Judge whether or not.

  When determining that there is no next page (S241: No), the control unit 101 causes the LED display unit 111 to blink an error (S249), and returns to S102 of the main process.

  If it is determined that there is a next page (S241: Yes), the control unit 101 determines whether the raster data of the next page is already stored in the page cache storage area 201 (S242).

  When the raster data of the next page is already stored in the page cache storage area 201 (S242: Yes), the control unit 101, based on the raster data of the next page stored in the page cache storage area 201, The display controller 102 is caused to rewrite the display on the nonvolatile display panel 103 (S243).

  If the next page raster data is not stored in the page cache storage area 201 (S242: No), the next page raster data is created based on the document file stored in the memory card 107 (S244).

  After creating the raster data for the next page, the control unit 101 rewrites the display on the nonvolatile display panel 103 based on the created raster data (S245).

  After rewriting the display on the nonvolatile display panel 103, the control unit 101 stores the created raster data in the page cache storage area 201 (S246). If raster data for five pages is already stored in the page cache storage area 201, raster data of a page far from the displayed page is deleted, and newly created raster data is stored.

  After performing S243 or S246, the control unit 101 updates the data stored in the displayed page number storage area 205 (S247). For example, if the sixth page is to be displayed as a result of the page being rewritten in S243 or S245, “6” is stored in the displayed page number storage area 205.

  After updating the data, the control unit 101 starts the above-described prefetching process (see FIG. 9) (S248), and proceeds to S102.

  Next, the previous key pressing process performed in S224 of the document display process will be described with reference to FIG. When the front key pressing process is started, the control unit 101 determines whether there is a page preceding the page being displayed (S261). Based on the page number stored in the displayed page number storage area 205, the control unit 101 determines whether there is a page preceding the page being displayed. If the page being displayed is one page, it is determined that there is no previous page.

  When determining that there is no previous page (S261: No), the control unit 101 causes the LED display unit 111 to blink an error (S269), and returns to S102 of the main process.

  If it is determined that there is a previous page (S261: Yes), the control unit 101 determines whether the raster data of the previous page is already stored in the page cache storage area 201 (S262).

  When the raster data of the previous page is already stored in the page cache storage area 201 (S262: Yes), the control unit 101, based on the raster data of the previous page stored in the page cache storage area 201, The display controller 102 is caused to rewrite the display on the nonvolatile display panel 103 (S263).

  If the previous page raster data is not stored in the page cache storage area 201 (S262: No), the previous page raster data is created based on the document file stored in the memory card 107 (S264).

  After creating the raster data for the previous page, the control unit 101 rewrites the display on the nonvolatile display panel 103 based on the created raster data (S265).

  After rewriting the display on the nonvolatile display panel 103, the control unit 101 stores the created raster data in the page cache storage area 201 (S266). If raster data for five pages is already stored in the page cache storage area 201, raster data of a page far from the displayed page is deleted, and newly created raster data is stored.

  After performing S263 or S266, the control unit 101 updates the data stored in the displayed page number storage area 205 (S267). For example, if the fourth page is to be displayed as a result of the page being rewritten in S263 or S265, “4” is stored in the displayed page number storage area 205.

  After updating the data, the control unit 101 starts the above-described prefetching process (see FIG. 9) (S268), and proceeds to S102.

  Next, with reference to FIG. 13, the close key pressing process performed in S226 of the above-described document display process will be described. When the close key pressing process is started, the control unit 101 rewrites the display on the non-volatile display panel 103 to a document selection screen (S281).

  After rewriting to the document selection screen, the control unit 101 deletes the raster data stored in the page cache storage area 201 (S282).

  Then, the data stored in the image type storage area 202, the displayed document name storage area 203, the page configuration storage area 204, and the displayed page number storage area 205 are updated (S283), and the process returns to S102 of the main process. Specifically, in S283, “document selection” is stored in the image type storage area 202, and NULL values are respectively displayed in the displayed text name storage area 203, the page configuration storage area 204, and the displayed page number storage area 205. Remember.

  Next, the power-off process performed by the control unit 101 in S105 of the main process will be described with reference to FIG. When the power-off process is started, the control unit 101 stores the data stored in the displayed document name storage area 203, the page configuration storage area 204, and the displayed page number storage area 205 as the displayed document name save area 302, the page configuration save area. The information is stored in the area 303 and the displayed page number saving area 304 (S301). The document name data stored in the displayed document name storage area 203 is saved in the displayed document name saving area 302, and the data for all the pages stored in the page configuration storage area 204 is saved in the page configuration saving area 303. Then, the page number data stored in the displayed page number storage area 205 is saved in the displayed page number saving area 304.

  Next, the control unit 101 determines whether a document selection screen is being displayed (S302). The control unit 101 makes a determination based on data stored in the image type storage area 202 of the RAM 52.

  If the data stored in the image type storage area 202 is “document selection” (S302: Yes), the display on the non-volatile display panel 103 is rewritten to a blank sheet (S303).

  After the display on the non-volatile display panel 103 is rewritten to blank, if there is raster data stored in the page cache save area 301 at the previous power-off, it is deleted (S304), and the process returns to S109 of the main process.

  When the data stored in the image type storage area 202 is “document” (S302: No), a power-off message is displayed in the margin of the document displayed on the nonvolatile display panel 103 (S305).

  After displaying the power-off message, if there is raster data stored at the time of the previous power-off in the page cache save area 301, it is deleted (S306).

  In step S306, after erasing the raster data in the page cache save area 301, the control unit 101 determines whether raster data is stored in the page cache area 201 of the RAM 52 (S307).

  If no raster data is stored in the page cache storage area 201 (S307: No), the process returns to S109 of the main process.

  When raster data is stored in the page cache storage area 201 (S307: Yes), the control unit 101 determines whether or not raster data for three pages has already been stored in the page cache save area 301. (S308).

  If raster data for three pages has already been stored (S308: Yes), the process returns to S109 of the main process.

  When raster data for three pages is not stored (S308: No), the control unit 101 acquires one of the raster data stored in the page cache storage area 201 in the work area of the RAM 52 (S309).

  Next, the size of the acquired raster data is compared with the free capacity of the page cache save area 301 of the internal memory 104, and it is determined whether or not there is a free capacity for storing the acquired raster data in the page cache save area 301. (S310). In this embodiment, the capacity of the page cache save area 301 is determined in advance.

  If it is determined that there is no free space in the page cache save area 301 (S310: No), the control unit 101 returns to S109 of the main process.

  When it is determined that the page cache save area 301 has free space (S310: Yes), the control unit 101 stores the acquired raster data in the page cache save area 301 of the internal memory 104 (S311).

  Then, the control unit 101 erases the raster data stored in the page cache save area 301 from the page cache storage area 201 (S312).

  After deleting one raster data in the page cache storage area 201, the control unit 101 determines whether or not the power key 151 is pressed again by the user (S313). The control unit 101 determines whether or not the user has pressed the power key 151 again based on whether or not key identification data for identifying the power key 151 is stored in the key buffer storage area 206.

  When the power key 151 has not been pressed again by the user (S313: No), the control unit 101 repeats the processes of S307 to S312 described above. In this way, raster data in the RAM 52 is saved in the internal memory 104 until there is no more free space in the page cache save area 301.

  If it is determined that the power key 151 is pressed again by the user (S313: Yes), the control unit 101 returns to S101 of the main process. As described above, when the power key 151 is pressed again by the user, the initial process is performed again without stopping the power supply, and the acceptance of the input operation from the user is resumed.

  As described above, the display device 100 stores raster data in the page cache save area 301 of the internal memory 104 before stopping the supply of power to the RAM 52. When the power is turned on again, the page can be rewritten based on the raster data stored in the page cache save area 301.

  It should be noted that the display device and the program of the display device of the present invention are not limited to the above-described embodiments, and it is needless to say that various changes can be made without departing from the gist of the present invention.

  The nonvolatile display panel 103 and the display controller 102 in the embodiment described above correspond to the nonvolatile display unit described in the claims. In the above-described embodiment, the nonvolatile display unit has been described as the nonvolatile display panel 103 and the display controller 102. However, any other display unit may be used as long as the display unit displays an image when the power is turned off. The present invention may be applied to a display device that can maintain display even when the power is turned off by continuing to supply power only to the display portion when the power is turned off.

  The memory card interface 106 and the memory card 107 in the above-described embodiment correspond to the image file acquisition unit described in the claims. In the above-described embodiment, the image file acquisition unit is described as the memory card interface 106 and the memory card 107. However, the image file acquisition unit may be a storage device such as a built-in flash memory.

  The RAM 52 in the above-described embodiment corresponds to the first storage unit described in the claims.

  The internal memory 104 in the above-described embodiment corresponds to the second storage part described in the claims. In the above-described embodiment, the second storage part is described as a non-volatile storage device. However, the storage unit may be a storage device that can maintain the storage by continuously supplying power when the power is turned off.

  The operation unit 105 in the above-described embodiment corresponds to the operation unit described in the claims.

  The power control unit 112 in the above-described embodiment corresponds to the power control unit described in the claims.

  The control unit 101 that performs S105 in the above-described embodiment corresponds to a raster data save control unit described in the claims.

  The control unit 101 that performs S101 in the above-described embodiment corresponds to a raster data return control unit described in the claims.

  The control unit 101 that performs S107 in the above-described embodiment corresponds to the rewrite control unit described in the claims.

  The control unit 101 that performs S304 or S306 in the above-described embodiment corresponds to a raster data deletion control unit described in the claims.

  The nonvolatile display panel 103 that displays a power-off message in accordance with the processing of S305 in the above-described embodiment corresponds to the notification unit described in the claims. In the above-described embodiment, the nonvolatile display panel 103 has been described as the notification unit. However, the notification may be performed by the LED display unit 111 or may be performed by using another device.

  Further, the control unit 101 in the above-described embodiment corresponds to the computer described in the claims.

  Further, the document file in the above-described embodiment corresponds to the image file described in the claims. In the above-described embodiment, the image file is a document file. However, the present invention is not limited to this.

  In addition, the power-on state in the above-described embodiment corresponds to the first power state described in the claims, and the power-off state in the above-described embodiments is the first power state described in the claims. This corresponds to two power states.

  Further, in the above-described embodiment, description has been made on the assumption that the pages before and after the displayed page are prefetched. However, the page cache storage area 201 stores the raster data of the page once displayed without performing prefetching. Good.

  In the above-described embodiment, the raster data stored in the page cache storage area 201 has been described as being stored in the page cache save area 301 as it is. However, when raster data is stored in the page cache save area 301, The data may be stored as a data file having a predetermined format with a predetermined header.

51 CPU
52 RAM
53 ROM
DESCRIPTION OF SYMBOLS 100 Display apparatus 101 Control part 102 Display controller 103 Nonvolatile display panel 104 Internal memory 105 Operation part 106 Memory card interface 107 Memory card 111 LED display part 112 Power control part

Claims (7)

A non-volatile display that maintains the display of the image even when the power supply is cut off,
An image file acquisition unit that acquires an image file that is an image data file;
Raster data created according to the image file acquired by the image file acquisition unit, storing at least one raster data of an image different from the image being displayed, and when power supply is cut off A first storage unit that is a volatile storage unit from which data is erased;
A second storage unit that is a storage unit provided separately from the first storage;
An operation unit that accepts user operations;
Power supply to the first storage unit is performed, the first power state in which the image of the nonvolatile display unit can be rewritten, and the power supply to the first storage unit is stopped, and the first power unit is stopped. A power control unit that switches between a second power state that consumes less power than the state;
Before the power control unit switches from the first power state to the second power state while the image based on the image file is displayed on the non-volatile display unit, the raster data stored in the first storage unit is stored. Raster data saving control unit to be stored in the second storage unit;
After the power control unit switches from the second power state to the first power state, a raster data return control unit that stores the raster data stored in the second storage unit in the first storage unit;
When the operation unit rewrites an image and the raster data corresponding to the rewritten image is stored in the first storage unit, the raster data stored in the first storage unit is stored in the raster data stored in the first storage unit. Therefore, when the image is rewritten and raster data corresponding to the rewritten image is not stored in the first storage unit, raster data is created from the image file acquired from the image file acquisition unit, and the generated raster data And a rewrite control unit for rewriting an image according to the above.   2. The raster data saving control unit according to claim 1, wherein only a part of raster data among a plurality of raster data stored in the first storage unit is stored in the second storage unit. Display device. When there is raster data stored in the second storage unit at the time of switching to the second power state last time,
In the period from the switching from the second power state to the first power state until the start of operation acceptance by the operation unit, the last stored raster data is not deleted,
2. The display according to claim 1, further comprising: a raster data deletion control unit that deletes the previously stored raster data before the raster data saving control unit stores the raster data in the second storage unit. apparatus.   The raster data saving control unit causes the second storage unit to store only the number of raster data that fits in a predetermined capacity among a plurality of raster data stored in the first storage unit. The display device according to claim 1. A notification unit for notifying the user that the power state has been switched to the second power state;
The raster data evacuation control unit stores the raster data stored in the first storage unit in the second storage unit after notifying that the notification unit has switched to the second power state. The display device according to claim 1.   After notifying the switching to the second power state by the notification unit, when the operation to switch to the first power state is received by the operation unit, the raster data saving control unit stores in the first storage unit The display device according to claim 5, wherein storage of the raster data that has been performed in the second storage unit is stopped. A non-volatile display that maintains the display of the image even when the power supply is cut off,
An image file acquisition unit that acquires an image file that is an image data file;
Raster data created according to the image file acquired by the image file acquisition unit, storing at least one raster data of an image different from the image being displayed, and when power supply is cut off A first storage unit that is a volatile storage unit from which data is erased;
A second storage unit that is a storage unit provided separately from the first storage;
An operation unit that accepts user operations;
Power supply to the first storage unit is performed, the first power state in which the image of the nonvolatile display unit can be rewritten, and the power supply to the first storage unit is stopped, and the first power unit is stopped. A power control unit that switches between a second power state that consumes less power than the state;
The raster data stored in the first storage unit before the power control unit switches from the first power state to the second power state while the image based on the image file is displayed on the nonvolatile display unit Raster data saving step to be stored in the second storage unit;
After the power control unit switches from the second power state to the first power state, a raster data return step for storing the raster data stored in the second storage unit in the first storage unit;
When the operation unit rewrites an image and the raster data corresponding to the rewritten image is stored in the first storage unit, the raster data stored in the first storage unit is stored in the raster data stored in the first storage unit. Therefore, when the image is rewritten and raster data corresponding to the rewritten image is not stored in the first storage unit, raster data is created from the image file acquired from the image file acquisition unit, and the generated raster data And a rewriting step of rewriting the image according to the above.