JP2008134418A - Image display system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device and an image display system capable of suppressing leakage of information. <P>SOLUTION: In the document display system 1, a plurality of security protection data for selection in which the security information is concealed are displayed on a display part 40 of a document display device 4A, one security protection data are selected by operation of an operation part 42 and, when the transmission of an image data corresponding to the one security protection data is demanded to a document management server 3A, the image data are transmitted from the document management server 3A and are displayed on the display part 40. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image display device and an image display system.

  Since electronic paper has a memory property that can hold the display of an image without a power source, when electronic paper on which an image is displayed is taken out, there is a risk of information leaking as in the case of using paper. is there.

As a conventional security system that prevents leakage of information held by electronic paper and prevents electronic paper from being taken out, for example, electronic paper has communication means and cannot receive from a specified area equipped with a specific radio wave source. Sometimes, a method of deleting the display of electronic paper is known (see Patent Document 1).
JP 2004-037829 A

  An object of the present invention is to provide an image display device and an image display system capable of suppressing leakage of information.

  As one aspect of the present invention, in order to achieve the above object, the following image display device and image display system are provided.

[1] For a display unit that can rewrite an image in accordance with a writing external force and displays and holds the formed image even after the writing external force is removed, and an image information transmitting apparatus connected to a network Request means for requesting the image information of the first page, a buffer memory for sequentially obtaining the bitmap-format image information of the first page requested by the request means, and the image information in the buffer memory In parallel with the sequential acquisition, a writing external force applying unit that applies a writing external force to the display unit according to information of each pixel included in the image information is acquired in the buffer memory. The displayed image information is erased after being used by the writing external force applying means.

[2] Image information transmitting means for sequentially transmitting image information in bitmap format via the network in response to a request signal input via the network, and an image rewritable according to the external writing force A display unit that displays and holds an image formed even after the writing external force is removed, a request unit that requests the image information of the first page from the image information transmission unit via a network, and the image A buffer memory for sequentially acquiring the image information of the first page from the information transmitting means, and in accordance with the information of each pixel included in the image information in parallel with the image information being sequentially acquired in the buffer memory Writing external force applying means for applying a writing external force to the display unit, and the image information acquired in the buffer memory is used by the writing external force applying means. Image display system characterized in that it is removed by.

[3] The image information transmission unit selects, as the first page image information requested by the request unit, bitmap-format image information from which at least a part of the first page image information is missing. The image information is transmitted as an image, and in response to a request from the request unit, bitmap-format image information in which the at least part of the first page is not lost is transmitted as a browsing image. The image display system according to [2].

[4] The image information transmitting means further transmits bitmap-format image information of a second page different from the first page as a browsing image, and the buffer memory selects the first page. The image information of the image for image and the image information of the image for browsing of the second page are obtained, and the writing external force applying means includes the image information of the image for selection of the first page stored in the buffer memory, and According to the image information of the browsing image of the second page, the display image of the first page and the browsing image of the second page are superimposed and displayed on the display unit. The image display system according to [3], wherein a writing external force is applied to the display unit.

[5] The above-mentioned [4], wherein the image information transmitting unit synthesizes and transmits the selection image for the first page and the browsing image for the second page as one image. Image display system.

[6] The writing external force applying means writes the selection image of the first page in a partial area of the display unit in a state where the browsing image of the second page is displayed on the display unit. The image display system according to [4] above, wherein

[7] The display system according to any one of [2] to [6], wherein the selection image is a reduced image.

[8] The request unit transmits information indicating the display capability of the display unit to the image information transmission unit, and the image information transmission unit determines the resolution of the image information according to the information indicating the display capability of the display unit. The display system according to any one of [2] to [7], wherein the display system is controlled.

  According to the image display device of the first aspect, even when the image display device is taken out or analyzed, information leakage can be stopped in one display image.

  According to the image display system of the second aspect, even when the image display device is taken out or analyzed, information leakage can be suppressed.

  According to the image display system of the third aspect, if the browsing image is not displayed, information leakage can be suppressed to the extent that the image information is partially missing.

  According to the image display system of the fourth aspect, leakage of information other than the browsing image can be suppressed to the level of information included in the selection image from which part of the image information is missing.

  According to the image display system of the fifth aspect, even if the image display device has an accident such as theft or loss, the outflow of information can be suppressed to the extent of the image information displayed on the display unit.

  According to the image display system of the sixth aspect, since the selection image is displayed in a partial area of the display medium, the transmission amount of image information and the load of the writing operation when the selection image is displayed can be reduced. .

  According to the image display system of the seventh aspect, the outflow of information is suppressed to the extent of the reduced selection image.

  According to the image display system of the eighth aspect, the steps and circuits for adjusting the acquired image information in accordance with the display unit are reduced.

  An image display device according to an embodiment of the present invention includes a display unit configured to display and hold an image formed so that an image can be rewritten according to a writing external force and the writing external force is removed. Request means for requesting the image information of the first page to the connected image information transmitting device, and a buffer memory for sequentially acquiring the bitmap-format image information of the first page requested by the request means And a writing external force applying means for applying a writing external force to the display unit in accordance with information of each pixel included in the image information in parallel with the image information being sequentially acquired in the buffer memory. The image information acquired in the buffer memory is erased after being used by the writing external force applying means.

  In addition, the image display system according to the embodiment of the present invention includes an image information transmitting unit that sequentially transmits image information in a bitmap format via a network in response to a request signal input via the network, and a writing An image is formed so as to be rewritable according to an external force, and a display unit that displays and holds the formed image even after the writing external force is removed, and a first page of the image information transmitting means via the network In parallel with the request means for requesting the image information, a buffer memory for sequentially acquiring the image information of the first page from the image information transmitting means, and the image information being sequentially acquired in the buffer memory, Writing external force applying means for applying a writing external force to the display unit in accordance with information of each pixel included in the image information, and the image information acquired in the buffer memory is It is intended to be erased after being used by the writing force applying means.

  The bitmap-format image information is a data reproduction method for expressing an image as an array / set of dots called colored dots, and in this embodiment, includes raster images. Bitmap format standards include PNG, JPEG, GIF, BMP, TIFF, PICT, and the like. In the vector graphics method, which mainly uses vectors that connect points, that is, contour lines, vector data needs to be calculated (rasterized) corresponding to the scaling of the displayed image, and converted into bitmap format data. Although the image processing load becomes large, the image information in the bitmap format does not need to be rasterized or has already been processed, so that it can be used with a small load for display on the dot matrix display unit. it can. This bitmap format image information is encoded directly or after a specified calculation process, after resizing when the number of data pixels does not match the number of pixels in the display unit, or by a predetermined data compression method or image compression method. If this information is decoded, it is provided as a drive signal to the driving element of the writing external force applying means for driving each pixel of the display unit after processing that is routine and less loaded than the rasterizing processing such as after decoding of this information. Is done.

  A buffer memory that temporarily holds image information for each pixel is provided so that a writing external force corresponding to the image information for each pixel is applied from the writing external force application means, and the image information for each pixel The driving element is applied so that an external force such as an electric field, a magnetic field, heat, light, a chemical action by applying a liquid having a predetermined pH, or the like is applied to the display material of the display unit. Operate.

  The display unit contains a display material constituting an image inside the display unit as a region for displaying and holding an image, and a writing external force (electricity, magnetism, heat, light, liquid having a predetermined pH is applied to the display material. The display material is physically or chemically changed to form an image corresponding to the writing external force, and after the writing external force is removed. However, the formed image is maintained, and when a different writing external force is applied, the previous image changes to an image corresponding to the new writing external force. In addition to the fact that the display state is maintained (stored) with no external writing force like that of paper, the display image can be rewritten without supplying a coloring material or developer from the outside. Because it is device-like, it is often called electronic paper.

  Further, the display unit is configured to display an image by a set of pixels by a dot matrix method, and each of the display units is sequentially applied by selectively applying a voltage to the electrode rows by a scan IC and a data IC provided at a location different from the display pixel. Scan rewriting is performed by display simple matrix driving for displaying an image on a pixel or active matrix driving for displaying an image on each pixel by selectively driving a driving element such as a TFT provided in the vicinity of each pixel. In accordance with the display principle of the display unit, a heating element is arranged instead of an electric field, and an electrode is arranged so as to cause a pH change accompanying voltage application.

  The buffer memory is a memory for temporarily storing image information in a dot matrix format transmitted from the image information transmitting means. After the image information is used for image display by the writing external force applying means, the CPU of the image display apparatus is used. Data is erased sequentially by inputting a data erase process or memory erase signal to the storage element by a control circuit, or by overwriting the memory contents with image information acquired afterwards without providing an erase process. The By setting the capacity to one page or less, the risk of information leakage due to remaining information other than the displayed information is reduced. By configuring the buffer memory with a FIFO memory, the risk of remaining information in the past is further reduced. The buffer memory can be configured not only as a page memory (frame memory), but also as a line memory for storing one to a plurality of lines. At this time, the circuit elements constituting the writing external force applying means are integrated in the line memory. It may be integrated in an integrated circuit (for example, a data IC).

  The image information transmission unit transmits, as the selection image, bitmap-format image information in which at least a part of the image information of the first page is missing as the image information of the first page requested by the request unit. In addition, in response to a request from the requesting unit, image information in a bitmap format in which the at least part of the first page is not lost may be transmitted as a browsing image.

  The request means is means for requesting image information of a predetermined page through a network, and may be integrated with the display unit or separated. As an aspect of the request means, various switches such as a push button type electric switch (button), a touch sensor, a voice or an optical sensor can be used. The number of sensing units constituting the request unit may be one or more. Various operations can be requested according to the number of times one button is pressed, the duration, or the pressing interval. Of course, a plurality of sensing units can be provided to enable various operations such as moving the page back and forth and selecting display / non-display of thumbnail images on the display unit.

  Prior to displaying the image information of the predetermined page on the display unit, when requesting the image information transmission means for bitmap-format image information in which at least a part of the image information is missing, the image information is transmitted more than the normal display image of the page. Information in which a part of the information is missing is transmitted as an image for selection. Examples of missing part of the information include lowering the resolution of the image compared to normal display, processing the character information included in the image information into an unreadable state, and conversely deleting images other than characters. Although it can be considered, any image may be used as long as the image for selection lacks more information than usual.

  The image information transmitting means further transmits bitmap-format image information of a second page different from the first page as a browsing image, and the buffer memory stores the selection image of the first page. The image information and the image information of the browsing image on the second page are acquired, and the writing external force applying means stores the image information of the selection image on the first page stored in the buffer memory and the second information. In accordance with the image information of the browsing image of the page, the display unit is configured to display the selection image of the first page and the browsing image of the second page superimposed on the display unit. Alternatively, a configuration in which a writing external force is applied may be employed.

  On the display unit, a browsing image is written on substantially the entire surface, and a selection image is displayed in a partial area. The display / non-display of the selection image may be set in advance by the system or may be switched by an operation such as turning on / off a button.

  The image information transmitting means may be configured to combine and transmit the selection image for the first page and the browsing image for the second page as one image.

  At this time, when switching the display / non-display of the selected image on the display device side, the image information transmitting means generates image information in which the image information of the selected image is preliminarily synthesized as a single image in a predetermined area of the browsing image. And can be transmitted to the display device.

  The writing external force applying means may be configured to write the selection image of the first page in a partial area of the display unit in a state where the browsing image of the second page is displayed on the display unit. Good.

  Alternatively, the selection image may be acquired from the image information transmission unit in a state where the browsing image has been written on the display unit, and this may be written in a partial area of the display unit. Since the display unit has a memory property that can hold an image even after the external writing force is removed, only a partial region of the display unit can be selectively rewritten.

  The selection image may be a reduced image.

  The request unit transmits information indicating the display capability of the display unit to the image information transmission unit, and the image information transmission unit controls the resolution of the image information according to the information indicating the display capability of the display unit. It is good also as a structure.

  The request means for requesting the image notifies the image information transmitting device of information such as the number of pixels in the vertical and horizontal directions and the number of colors of the display unit on which the image is displayed when the image is requested. You may make it transmit the image information after performing resolution, a color, and gradation conversion by the transmitter side. The correspondence relationship between the display capabilities of the display unit and the display unit is stored and held on the image information transmitting apparatus side, and the code information for identifying the display unit is transmitted from the requesting unit, and the display capability is discriminated accordingly. You may do it.

[First Embodiment]
FIG. 1 is a diagram showing a document display system (image display system) according to the first embodiment of the present invention. The document display system 1 includes a control personal computer (PC) 2 for selecting document data, a document management server 3A for storing a plurality of document data and outputting the document data selected by the control PC 2, and a document And a document display device (image display device) 4A for displaying document data output from the management server 3A.

  The control PC 2 and the document management server 3A are connected via a communication cable 5. The document management server 3A and the document display device 4A communicate with each other by wireless communication 6 such as ZigBee (registered trademark), Bluetooth (registered trademark), wireless LAN (Local Area Network), and infrared communication, but using a communication cable. May be.

  The control PC 2 includes a CPU that controls each unit of the control PC 2, a storage unit that stores various programs and data, an input unit such as a keyboard and a mouse, a display unit such as a liquid crystal display, and a document management server 3A. And a communication unit that communicates with each other, and has a function of requesting a document to be displayed on the document display device 4A among the document data stored in the document management server 3A. The control PC 2 may be a terminal of the document management server 3A.

  The document display device 4 </ b> A includes a display unit 40 having a memory property (nonvolatile) capable of holding an image display with no power supply, a frame unit 41 that supports the display unit 40, and an operation unit 42 provided in the frame unit 41. With. The operation unit 42 includes a page feed button 420a, a page return button 420b, and a switching / confirmation 421.

  The display unit 40 has a plurality of signal electrodes to be described later, a plurality of scan electrodes to be described later arranged so as to be orthogonal to these signal electrodes, and a memory property disposed between the plurality of signal electrodes and the plurality of scan electrodes. A display layer. As the display layer having a memory property, for example, a liquid crystal such as a cholesteric liquid crystal or a ferroelectric liquid crystal can be used. The display layer is not limited to liquid crystal, but an electrophoresis system that switches charged particles by moving charged particles, a particle rotation method that switches charged particles by rotating charged particles, and a magnet that switches particles by moving particles by magnetism. Other display layers such as an electrophoretic method may be used. By using a display layer having a memory property, almost no power is required to hold an image display, so that power saving can be achieved.

  In addition, the display layer is a liquid crystal display (LCD) using liquid crystal such as nematic liquid crystal, ELD (electroluminescence display), PDP (plasma display), VFD (fluorescent display), LED (light emitting diode) display, FED ( It may be one having no memory property such as a field emission display. By using a display layer that does not have memory properties, the display image disappears at the same time as the power is turned off, so that information leakage can be further suppressed.

  FIG. 2 is a block diagram of the document management server 3A. The document management server 3A includes a page ID for each page of the page of the document selected by the control unit 30A that controls each unit of the document management server 3A, the storage unit 31 such as an HDD that stores the document data 10, and the control PC 2. A page ID generation unit 32 that generates image data, an image data creation unit 33 that creates image data in a bitmap format for display that can be displayed by the document display device 4A for the page of the selected document, and a page of the selected document Is provided with a security data creation unit 34 for creating security data for selection in which confidential information is concealed, and a communication unit 35 that communicates with the document display device 4A. Note that, when a predetermined document is registered in the document management server 3A or the like or at a predetermined time, bitmap image data is automatically generated in advance and associated with the document file name regardless of whether or not the document is selected. May be stored in memory.

  The document data 10 stored in the storage unit 31 is data created by application software such as document creation software. The document data 10 is not limited to a document, and is an image such as a figure or a photograph, or an image in which a document and a figure or a photograph are mixed. It may be.

  For example, the confidential data creation unit 34 searches a character string (for example, a telephone number) set in advance with respect to the document data 10, and uses a character (for example, an unreadable character so as not to understand the original meaning). ***), but is not limited to this method.

  FIG. 3 is a block diagram of the document display device 4A. The document display device 4A stores a control unit 43A that controls each unit of the device 4A, a communication unit 44 that communicates with the document management server 3A, and image data that is written to the display unit 40 acquired via the communication unit 44. The memory electrode 46, the signal electrode driver 47A for driving the signal electrode 401 based on the data written in the display memory 46 based on the operation of the operation unit 42, and the scanning electrode 402 are sequentially arranged in the direction of the arrow in FIG. A scanning electrode driving unit 47B for scanning.

  The signal electrode 401 and the scanning electrode 402 are driven by a simple matrix (passive matrix) driving method by the signal electrode driving unit 47A and the scanning electrode driving unit 47B. In addition, as a pair of electrodes facing each other, an entire surface electrode and a plurality of pixel electrodes are used, and active elements such as TFTs are respectively connected to intersections of a plurality of data lines and a plurality of scanning lines orthogonal to each other, and active matrix driving is performed. Each pixel may be driven.

(Operation of the document display system)
Next, the operation of the document display system 1 will be described with reference to the flowchart shown in FIG.

  FIG. 5 is a flowchart showing the operation of the document management server 3A. The user operates the input unit of the control PC 2 to select a document and page to be output to the document display device 4A (S1). Only the document may be selected. Thereby, the trouble of selecting individual pages in the document can be saved.

  The page ID generation unit 32 of the document management server 3A generates a page ID for each page of the selected document page. The image data creation unit 33 creates bitmap-format browsing image data (viewing image) 11 that can be displayed on the document display device 4A for the selected document page. The confidential data generation unit 34 generates confidential data (selection image) 12 that is image data for selection in a bitmap format in which information is concealed by deleting a part of the image for the page of the selected document. (S2). Note that the image data creation unit 33 may create image data for only the first page to be displayed among the designated pages, and then create image data for the requested page.

  The control unit 30A documents a page image and a browsing image file in which data identification information for identifying whether the data is confidential data or image data is added to all pages of the confidential data 12 via the communication unit 35. Transfer to display device 4A.

  When the communication unit 44 receives the image file transferred from the document management server 3A, the control unit 43A of the document display device 4A stores the confidential data 12 together with the page ID in the confidential data memory 45A based on the data identification information. .

  The control unit 43A also stores the confidential data 12 stored in the confidential data memory 45A in the display memory 46 for the designated page, and the display unit 40 is driven by the signal electrode driver 47A and the scan electrode driver 47B. The confidential data 12 is displayed. That is, the signal electrode driver 47A applies a voltage based on the data read from the display memory 46 for each line to each signal electrode 401. The scan electrode driver 47B sequentially applies a selection voltage to each scan electrode 402 in synchronization with the voltage application of the signal electrode driver 47A. When the display is completed, the contents of the display memory 46 are erased.

  FIG. 4A shows an example of confidential data displayed on the display unit 40. The confidential data 12 displayed on the display unit 40 is displayed with confidential information 120 such as a telephone number hidden.

  Here, when the user presses the page feed button 420a or the page return button 420b to perform page advance or return, the control unit 43A controls the corresponding confidential information based on the operation of the page feed button 420a or the page return button 420b. The retained data 12 is read from the confidential retained data memory 45A and written to the display memory 46. Subsequently, the control unit 43A displays the confidential data 12 on the display unit 40 by driving by the signal electrode driving unit 47A and the scanning electrode driving unit 47B. When the display is completed, the contents of the display memory 46 are erased.

  When the confidential data 12 desired to be displayed as image data is displayed on the display unit 40, the user presses the switch / confirm button 421. The control unit 43A transmits an image data request signal together with the page ID of the confidential data to the document management server 3A via the communication unit 44 (S3).

  When receiving the request signal from the document display device 4A (S4: Yes), the control unit 30A of the document management server 3A reads the image data 11 corresponding to the requested page ID from the storage unit 31, and stores the image data 11 in the image data 11. The page ID and data identification information for identifying whether the data is confidential data or image data are added and transferred to the document display device 4A via the communication unit 35 (S5).

  When receiving the image data 11 transferred from the document management server 3A by the communication unit 44, the control unit 43A of the document display device 4A stores the image data 11 in the display memory 46 based on the data identification information, as described above. Then, the image data 11 is displayed on the display unit 40 by driving the signal electrode driving unit 47A and the scanning electrode driving unit 47B. When the display is completed, the contents of the display memory 46 are erased.

  FIG. 4B shows an example of image data displayed on the display unit 40. The image data 11 displayed on the display unit 40 is displayed without concealing confidential information 120 such as a telephone number, for example.

  Thereby, even if the document display device 4A is taken out, the information of the image data for one page displayed on the display unit 40 is leaked, but the confidential information is concealed for other pages. Leakage can be suppressed.

[Second Embodiment]
FIG. 6 is a diagram showing a document display system (image display system) according to the second embodiment of the present invention. The document display system 1 includes a control PC 2 for selecting document data, a document management server 3B for storing a plurality of document data and outputting the document data selected by the control PC 2, and an output from the document management server 3A. The document management server 3B and the document display device 4B are different from the first embodiment. The document display device (image display device) 4B displays the document data.

  The document display device 4B includes a display unit 40, a frame unit 41, and an operation unit 42 as in the first embodiment.

  FIG. 7 is a block diagram of the document management server 3B. Similarly to the first embodiment, the document management server 3B includes a control unit 30B, a storage unit 31, a page ID generation unit 32, an image data creation unit 33, and a communication unit 35. Instead of the confidential data creation unit 34, a reduced data creation unit 36 that creates reduced data for the page of the selected document is provided.

  The reduced data creating unit 36 converts the document data into image data that can be displayed by the document display device 4B and reduces the image data to such an extent that confidential information included in the document data is unreadable. Here, “reducing image data” means reducing the total number of pixels. For example, image data is thinned out and reduced, but the reduction method is not limited to this.

  FIG. 8 is a block diagram of the document display device 4B. Similar to the first embodiment, the document display device 4B includes a communication unit 44, a display memory 46, a signal electrode drive unit 47A, and a scan electrode drive unit 47B, but the control unit 43B and the reduced data memory 45B are different. .

  In the reduced data memory 45B, the reduced data 13 for selection is stored for all selected pages together with the page ID.

  When there is a display request for the reduced data 13 by the operation of the operation unit 42, the control unit 43 B writes the reduced data 13 in the reduced data writing area 46 a formed in a part of the display memory 46, and stores the reduced data 13 in the reduced data 13. The signal electrode driver 47A and the scan electrode driver 47B are controlled so as to drive only the corresponding signal electrode 401 and scan electrode 402. The scan electrode driver 47B sequentially scans the scan electrodes 402 in the direction indicated by the arrow in FIG. 8, and the reduced data writing area 46a is provided on the scan start side. Thereby, the time until the reduced data 13 is written can be shortened.

(Operation of the document display system)
Next, the operation of the document display system 1 will be described with reference to the flowchart shown in FIG.

  FIG. 10 is a flowchart showing the operation of the document management server 3B. The user operates the input unit of the control PC 2 to select a document and page to be output to the document display device 4B (S11). Only the document may be selected. Thereby, the trouble of selecting individual pages in the document can be saved.

  The page ID generation unit 32 of the document management server 3B generates a page ID for each page of the selected document page. The image data creation unit 33 creates image data for browsing (viewed image) 11 in a bitmap format that can be displayed on the document display device 4B for the page of the selected document. The reduced data creating unit 36 creates reduced data (selection image) 13 that is image data in the bitmap format for the selected document page (S12). Note that the image data creation unit 33 may create image data for only the first page to be displayed among the designated pages, and then create image data for the requested page.

  The control unit 30B adds the page ID and the data identification information to the image data 11 of a predetermined page (for example, the smallest page among all selected pages), and adds the page ID and the data identification information to the reduced data 13 The image file is transferred to the document display device 4B via the communication unit 35 (S13).

  When receiving the image file transferred from the document management server 3B by the communication unit 44, the control unit 43B of the document display device 4B stores the reduced data 13 together with the page ID in the reduced data memory 45B based on the data identification information.

  The control unit 43B stores the image data 11 in the display memory 46, and causes the display unit 40 to display the image data 11 by driving by the signal electrode drive unit 47A and the scan electrode drive unit 47B. That is, the signal electrode driver 47A applies a voltage based on the data read from the display memory 46 for each line to each signal electrode 401. The scan electrode driver 47B sequentially applies a selection voltage to each scan electrode 402. When the display is completed, the contents of the display memory 46 are erased.

  FIG. 9A shows an example of the image data 11 displayed on the display unit 40. The image data 11 displayed on the display unit 40 is displayed without being concealed even when confidential information is included.

  When the user operates the switching / confirmation button 421 of the operation unit 42 of the document display device 4B, the control unit 43B reads the reduced data 13 from the second memory 45B and writes it to the reduced data writing area 46a of the display memory 46. The reduced data 13 is displayed (overwritten) on a part (upper right) of the image data 11 displayed on the display unit 40 by driving by the signal electrode driving unit 47A and the scanning electrode driving unit 47B. That is, only the signal electrode 401 and the scan electrode 402 corresponding to the reduced data writing area 46 a of the display memory 46 are driven to write the reduced data 13 on the display unit 40. Display of the image data 11 other than the reduced data 13 is maintained even when no voltage is applied due to the memory property of the display unit 40.

  FIG. 9B shows a state in which the reduced data 13 is written in a part of the image data 11 displayed on the display unit 40.

  Here, when the user presses the page feed button 420a or the page return button 420b to advance or return the page, the control unit 43B controls the corresponding reduced data 13 based on the operation of the page feed button 420a or the page return button 420b. Is read from the second memory 45B and written into the reduced data writing area 46a of the display memory 46. The reduced data 13 is displayed on the display unit 40 by driving by the signal electrode driving unit 47A and the scanning electrode driving unit 47B.

  When the reduced data 13 desired to be displayed as the image data 11 is displayed on the display unit 40, the user presses the switch / confirm button 421. The control unit 43B transmits an image data request signal together with the page ID of the reduced data 13 to the document management server 3B via the communication unit 44 (S13).

  The control unit 30B of the document management server 3B reads the image data 11 corresponding to the requested page ID from the storage unit 31, and transmits the image data 11 together with the page ID to the document display device 4B via the communication unit 35 (S15).

  The control unit 43B of the document display device 4B stores the image data 11 transferred from the document management server 3B in the display memory 46, and the display unit 46B is driven by the signal electrode drive unit 47A and the scan electrode drive unit 47B as described above. 40 displays the image data 11 as shown in FIG. When the display is completed, the contents of the display memory 46 are erased.

  Thereby, even if the document display device 4B is taken out, the information of the image data for one page displayed on the display unit 40 is leaked, but the confidential information is reduced to be unreadable for the other pages. Therefore, information leakage can be suppressed.

[Other embodiments]
The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention. In addition, the constituent elements of the above embodiments can be arbitrarily combined without departing from the spirit of the invention.

  A plurality of confidential data may be reduced and displayed on the display unit. Thereby, confidential information can be further concealed. Further, a plurality of confidential data may be reduced and displayed in multiple on the display unit. As a result, when selecting confidential data, the number of page feed or return operations can be reduced.

  In addition, the browsing image is transmitted from the document management server to the document display device for the first page to be displayed among the designated pages, and the browsing image is displayed. Then, the selection image is documented for all the designated pages. For viewing corresponding to the selection image in response to a request from the document display device by displaying the selection image on a part of the display area of the document display device (or the entire display area) by transmitting from the management server to the document display device The image may be transmitted from the document management server to the document display device and displayed.

It is a figure which shows the document display system which concerns on the 1st Embodiment of this invention. It is a block diagram of the document management server shown in FIG. It is a block diagram of the document display apparatus shown in FIG. (A), (b) is a figure which shows an example of the image displayed on the document display apparatus shown in FIG. It is a flowchart which shows operation | movement of the document management server which concerns on the 1st Embodiment of this invention. It is a figure which shows the document display system which concerns on the 2nd Embodiment of this invention. FIG. 7 is a block diagram of the document management server shown in FIG. 6. FIG. 7 is a block diagram of the document display device shown in FIG. 6. (A)-(c) is a figure which shows an example of the image displayed on the document display apparatus shown in FIG. It is a flowchart which shows operation | movement of the document management server which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

1 Document display system 2 Control PC
3A, 3B Document management server 4A, 4B Document display device 5 Communication cable 6 Wireless communication 10 Document data 11 Image data 12 Security data 13 Reduced data 30A, 30B Control unit 31 Storage unit 32 Page ID generation unit 33 Image data creation unit 34 Security data creation unit 35 Communication unit 36 Reduced data creation unit 40 Display unit 41 Frame unit 42 Operation units 43A and 43B Control unit 44 Communication unit 45A Security data memory 45B Reduced data memory 46 Display memory 46a Reduced data write area 47A Signal Electrode driver 47B Scan electrode driver 120 Confidential information 401 Signal electrode 402 Scan electrode 420a Page feed button 420b Page return button 421 Switch / confirm button

Claims (8)

A display unit configured to display and hold the formed image even after the image is formed so as to be rewritable according to the writing external force and the writing external force is removed;
Requesting means for requesting the image information of the first page from the image information transmitting apparatus connected to the network;
A buffer memory for sequentially obtaining image information in the bitmap format of the first page requested by the requesting unit;
A writing external force applying means for applying a writing external force to the display unit according to information of each pixel included in the image information in parallel with the image information being sequentially acquired in the buffer memory;
With
The image display apparatus, wherein the image information acquired in the buffer memory is erased after being used by the writing external force applying means. In response to a request signal input via a network, image information transmission means for sequentially transmitting bitmap format image information via the network;
A display unit configured to display and hold the formed image even after the image is formed so as to be rewritable according to the writing external force and the writing external force is removed;
Requesting means for requesting the image information of the first page to the image information transmitting means via a network;
A buffer memory for sequentially obtaining the image information of the first page from the image information transmitting means;
A writing external force applying means for applying a writing external force to the display unit according to information of each pixel included in the image information in parallel with the image information being sequentially acquired in the buffer memory;
With
The image information acquired in the buffer memory is erased after being used by the writing external force applying means.   The image information transmission unit transmits, as the selection image, bitmap-format image information in which at least a part of the image information of the first page is missing as the image information of the first page requested by the request unit. In addition, according to a request from the request unit, bitmap-format image information in which the at least part of the first page is not missing is transmitted as a browsing image. The image display system described. The image information transmitting means further transmits bitmap image information of a second page different from the first page as a browsing image,
The buffer memory acquires image information of the selection image of the first page and image information of the browsing image of the second page,
The writing external force applying means is arranged on the display unit according to image information of the selection image of the first page and image information of the browsing image of the second page stored in the buffer memory. 4. The image according to claim 3, wherein a writing external force is applied to the display unit so that the selection image for one page and the browsing image for the second page are displayed in a superimposed manner. 5. Display system.   5. The image display system according to claim 4, wherein the image information transmission unit synthesizes and transmits the selection image of the first page and the browsing image of the second page as one image. .   The writing external force applying means writes the selection image of the first page in a partial area of the display unit in a state where the browsing image of the second page is displayed on the display unit. The image display system according to claim 4.   The display system according to claim 2, wherein the selection image is a reduced image.   The request unit transmits information indicating the display capability of the display unit to the image information transmission unit, and the image information transmission unit controls the resolution of the image information according to the information indicating the display capability of the display unit. The display system according to claim 2, wherein the display system is a display system.

Images