JP2004233657A - Display device and copy prevention method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent unauthorized copy of information displayed on a reflection type or semi-reflection type display medium. <P>SOLUTION: When light moving at a fixed speed in a fixed direction is detected by an optical sensor 12, a control signal and an address are outputted to a control part 16 by a CPU 14 so that an image displayed on the display medium 20 is erased or changed. The control part 16 controls driving of the display medium 20 so that the displayed image is erased or changed on the basis of the input from the CPU 14. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device and a copy protection method, and more particularly to a display device and a copy protection method having a function of preventing unauthorized copying of an image displayed on a display medium such as electronic paper.
[0002]
[Prior art]
A display medium collectively called electronic paper has display characteristics (high contrast and high resolution) like paper and requires energy to display, but the display element itself has a memory property and thus the display content is high. It does not require energy for maintenance.
[0003]
In such electronic paper, minute spheres painted separately in white and black are embedded in a transparent sheet, and the black and white portions of the minute spheres are charged differently. It is known that a sphere rotates to perform black and white display (for example, see Patent Document 1).
[0004]
In addition, there is a device in which monopolarly charged microspheres move in the direction of an electric field, are attracted to a wall and are stabilized, and the state is maintained (for example, see Patent Document 2). Similarly, electronic paper (see, for example, Patent Document 3) in which a sphere moves and displays in a minute space is widely known, and these are called an electrophoretic system or a magnetophoretic system, and are currently being actively used. Researched and developed.
[0005]
Further, a liquid crystal using a ferroelectric liquid crystal (for example, see Patent Documents 4 and 5) and a liquid crystal using a cholesteric liquid crystal (for example, see Non-Patent Document 1) are widely known.
[0006]
[Patent Document 1]
JP-A-3-188489
[Patent Document 2]
U.S. Pat. No. 5,262,098
[Patent Document 3]
JP-A-2002-169190
[Patent Document 4]
JP 2000-148116 A
[Patent Document 5]
JP-A-5-35223
[Non-patent document 1]
Hiroshi Arisawa and one other, "Optical Address Electronic Paper", "Fuji Xerox Technical Report No. 14 2002", Fuji Xerox Co., Ltd., June 25, 2002, p. 89
[0007]
[Problems to be solved by the invention]
Since such electronic paper has a characteristic like paper as described above, the display content can be read by a scanner or a copying machine or the like, and can be easily copied, similarly to paper. On the other hand, when the electronic paper displays the confidential information, the confidential information is leaked to the outside because the confidential information can be easily copied.
[0008]
If the display medium is paper, an invisible small image pattern is embedded using cherry paper, and when the image is copied, the embedded image pattern emerges to prevent copying. This is difficult to achieve because the current electronic paper requires higher resolution. There is also a technique of embedding an IC chip to prevent forgery. However, since a copying machine that does not support the IC chip can easily make a copy, illegal copying of electronic paper cannot be reliably prevented.
[0009]
SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-described problems, and a display device and a copy prevention method capable of preventing unauthorized copying of information displayed on a reflective or semi-reflective display medium. It is intended to provide.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a display device of the present invention includes a reflective or semi-reflective display medium, storage means for storing display data, and a constant speed in a certain direction when irradiated on the display medium. Detecting means for detecting light moving in the display means, and controlling the driving of the display medium so that an image is displayed on the display medium based on display data stored in the storage means; Display erasing control means for controlling the driving of the display medium so that the image displayed on the display medium is erased or changed when the light is detected. .
[0011]
In the present invention, display data is stored in the storage means. The control unit controls the driving of the display medium so that an image is displayed on the display medium based on the display data stored in the storage unit. Further, the detecting means detects light which is emitted to the reflective or semi-reflective display medium and moves at a constant speed in a constant direction. The display erasure control unit controls the driving of the display medium so that the image displayed on the display medium is erased or changed when the light is detected by the detection unit.
[0012]
2. Description of the Related Art An image input device such as a copier or a scanner device irradiates a strong light (scanning light) having a predetermined value or more to electronically read display contents on a display medium. Although the amount of light of the scan light, the moving speed and the moving direction vary depending on the apparatus, the apparatus is characterized in that the apparatus moves in a fixed direction at a constant speed in common to each apparatus. According to the configuration of the present invention, when the detection unit detects the light having this characteristic, the control unit deletes or changes the image displayed on the display medium, so that the image displayed on the display medium is illegal. Can be easily and reliably prevented from being copied. Therefore, even if the image displayed on the display medium contains confidential data, leakage of the confidential data can be prevented with high reliability. This allows, for example, reflective or semi-reflective display media such as electronic paper to be used on more business occasions.
[0013]
Further, in the present invention, the display medium is a display medium in which a scanning electrode and an information electrode are arranged so as to be orthogonal to each other, and the display erasing control unit is configured to detect the light when the detection unit detects the light. The moving direction of the light detected by the detecting means is determined, and if the moving direction is smaller than a predetermined angle with respect to the arrangement direction of the scanning electrodes on the display medium, the moving direction is within a predetermined area including the light irradiation position on the display medium. Controlling the driving of the display medium so that the image displayed on the display medium is erased or changed, and when the moving direction is a predetermined angle or more with respect to the arrangement direction of the scanning electrodes of the display medium, The driving of the display medium may be controlled such that the entire image displayed on the screen is collectively erased or changed.
[0014]
That is, when the scan light is emitted obliquely to the arrangement direction of the scan electrodes on the display medium, the image displayed on the display medium is partially erased or changed, for example, along the arrangement direction of the information electrodes. Even if the entire page is copied by the scanning light, only partially erased or changed oblique lines are displayed on the result, and it is highly possible that the contents can be read. Therefore, in this case, if the drive of the display medium is controlled so that the entire image is collectively erased or changed, copying is completely prevented and leakage of confidential matters can be prevented.
[0015]
Further, the display erasure control means of the present invention, when the light is detected by the detection means, obtains a light irradiation position on the display medium based on the detection by the detection means, and determines the obtained irradiation position. The drive of the display medium can be controlled so that the image displayed in the predetermined area including the image is erased or changed.
[0016]
Thus, only the image displayed in the predetermined area including the irradiation position of the scan light on the display medium is deleted or changed, so that copying can be prevented efficiently.
[0017]
Further, the display erasing control means of the present invention may be arranged such that, among the erased or changed areas, an area other than a predetermined area including a current irradiation position is restored to a display state before erasing or before changing. The driving of the display medium can be controlled.
[0018]
As a result, the area where the scanning light irradiation from the copying machine, the scanner device, or the like has been completed is restored to the original display state, and eventually the display on the display medium side is entirely in the original display state. .
[0019]
Further, the display medium of the present invention may have a memory property.
[0020]
This eliminates the need for energy for maintaining the display on the display medium.
[0021]
Further, the display medium and the detection means of the present invention may be provided so as to be separable from the storage means and the display erasure control means.
[0022]
Thus, the display media can be used separately.
[0023]
Further, in the present invention, in the state where the display medium and the detection means are separated from the storage means and the display erasure control means, the light is transmitted by the detection means instead of the display erasure control means. Erasing control means for controlling the driving of the display medium such that the image displayed on the display medium is erased when is detected, and the erasing control means performs at least one erasing. And a battery that stores the energy that can be generated.
[0024]
That is, in a state where the display medium and the detection means are separated from the storage means and the display erasure control means, when the detection means detects light that irradiates the display medium and moves at a constant speed and a constant speed, the display erasure is stopped. The erasing control means controls the driving of the display medium so that the image displayed on the display medium is erased instead of the use control means.
[0025]
Thus, even when the display medium is used separately, illegal copying can be prevented.
[0026]
Further, according to the present invention, together with the display medium, the detection means, the erasure control means, and the battery, the storage means and the display erasure control means are provided so as to be separable from each other, and a photovoltaic power generation using received light is performed. And the erasing control means controls the driving of the display medium using the energy obtained by the photovoltaic power generation of the power generating means.
[0027]
Thus, for example, by repeatedly separating and using the display medium, even if the battery does not have a sufficient capacity for erasing by the erasing control unit, the battery can be used by photovoltaic power generation without replacing the battery. Energy can be obtained, so that unauthorized copying can be prevented.
[0028]
In the present invention, the display data stored in the storage means is provided with identification data indicating whether or not an image displayed based on the display data is copy-prohibited. The means or the erasing control means is displayed on the display medium when the light is detected by the detection means and the identification data of the display data used for displaying the display medium is copy-prohibited. The driving of the display medium may be controlled such that the image is erased or changed.
[0029]
In this manner, if the display data of the image displayed on the display medium is provided with identification data indicating whether or not copying is prohibited, it is determined whether or not the image displayed on the display medium is prohibited from being copied. Since it becomes possible, it is possible to efficiently perform a change or delete process for preventing copying.
[0030]
Further, the detection means of the present invention may be arranged in a display area of the display medium.
[0031]
This makes it possible to detect only the light radiated into the display area of the display medium, so that copying can be efficiently prevented.
[0032]
Further, a plurality of the detecting means of the present invention may be provided.
[0033]
This makes it possible to detect illegal light with high certainty.
[0034]
Further, the detecting means of the present invention may be arranged in at least one corner of the display medium in an L-shape along a vertical direction and a horizontal direction.
[0035]
This makes it possible to accurately detect not only light radiated parallel to the vertical and horizontal directions of the display medium but also light radiated obliquely at a predetermined angle.
[0036]
Further, the display erasure control means of the present invention, when changing the display of the display medium, displays a predetermined message or advertisement instead of the display using the display data stored in the storage means. Alternatively, the driving of the display medium may be controlled.
[0037]
That is, for example, a warning message of copy prohibition may be displayed on the display medium, or an advertisement of a company may be displayed. This allows a reflective or semi-reflective display medium such as electronic paper to be used in more business opportunities.
[0038]
The copy preventing method according to the present invention further comprises a determining step of determining whether or not a light radiated on a reflective or semi-reflective display medium and moving at a constant speed in a fixed direction is detected. And controlling the driving of the display medium so that the image displayed on the display medium is erased or changed when it is determined that the light is detected.
[0039]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
[0040]
FIG. 1 is a schematic configuration diagram of a display device according to a first embodiment to which the present invention is applied.
[0041]
The illustrated display device 10 includes a reflective display medium 20, a dual-port VRAM 18, an optical sensor 12, a CPU 14, and a control unit 16.
[0042]
The display medium 20 is a dot matrix type ferroelectric liquid crystal display medium, and includes a display section 22, a common driver 24 which is a liquid crystal driving IC on the common side (scan line side) of the display section 22, and a segment side (information line). Side) A segment driver 26 which is a liquid crystal driving IC is provided. Note that a scanning electrode is connected to an output terminal of the common driver 24, an information electrode is connected to an output terminal of the segment driver 26, and the scanning electrode and the information electrode in the display unit 22 are arranged so as to be orthogonal to each other. The display unit 22 has a structure in which ferroelectric liquid crystal is sandwiched between transparent substrates or the like, and a reflective polarizing layer (eg, RDF-C (trade name) manufactured by Sumitomo 3M) is laminated on one surface thereof. (See FIG. 6).
[0043]
The VRAM 18 stores, in addition to display data for displaying an image on the display medium 20, warning display data for displaying a copy prohibition warning message, and advertisement display data for displaying an advertisement. I have. The display data has identification data indicating whether or not the image displayed on the display medium 20 as the display data is copy-prohibited.
[0044]
The optical sensor 12 detects light having a light amount equal to or more than a predetermined value applied to the display medium 20. The light (scanning light) emitted by an image input device such as a copier or a scanner device when reading is varied in the amount of light, the moving speed and the moving direction for each device, but is common to each device in a fixed direction. It has the feature of moving at a constant speed. Therefore, unauthorized copying is detected by detecting light having this characteristic with the optical sensor 12.
[0045]
In the present embodiment, a plurality of optical sensors 12 are provided at regular intervals in an L-shape at one corner of the display medium 20 outside the display area of the display medium 20 as shown in FIG. I have.
[0046]
In addition, as shown in FIG. 3, the optical sensor 12 may be configured by an elongated sensor provided along an edge outside the display area of the display medium 20 and a plurality of square sensors. As shown in FIG. 4, the display medium 20 may be provided in an L-shape outside the four corner display areas as in FIG. 2. Further, as shown in FIG. 5, a plurality of L-shapes may be provided at each of the four corners in the display medium. In this case, as shown in the cross-sectional view of the display medium in FIG. 6, the optical sensor 12 includes a polarizing layer 22a, a transparent substrate 22b, a scanning electrode 22c, an insulating layer 22d, a ferroelectric liquid crystal 22e, an insulating layer 22f, and an information electrode. In the display unit 22 including the transparent substrate 22g, the transparent substrate 22h, the reflective polarizing layer 22i, and the light shielding layer j, for example, it may be provided between the reflective polarizing layer 22i and the light shielding layer 22j. Further, the number of the optical sensors 12 arranged on the display medium 20 is plural in the drawings shown in FIGS. 2 to 6, but may be singular.
[0047]
The CPU 14 is connected to the VRAM 18 via address / data / control lines, and the control unit 16 is connected to the VRAM 18 via image data / memory control lines.
[0048]
The CPU 14 outputs an address for reading display data from the VRAM 18 to the control unit 16 and outputs a control signal for displaying an image on the display medium 20. Also, based on the detection result of the optical sensor 12, a control signal for erasing the image displayed on the display medium 20, a control signal for displaying a warning message or an advertisement instead of the displayed image, and a warning signal from the VRAM 18. An address for reading the display data or the advertisement display data is output to the control unit 16.
[0049]
Note that a memory (not shown) is connected to the CPU 14, and this memory stores data indicating whether the display medium 20 is of a matrix drive system.
[0050]
The control unit 16 reads display data and the like based on the address input from the CPU 14, and controls the driving of the display medium 20 (specifically, the common driver 24 and the segment driver 26) based on the input control signal. .
[0051]
Hereinafter, the display control processing according to the present embodiment will be described.
[0052]
The CPU 14 outputs a control signal for displaying the display data and an address for reading the display data from the VRAM 18 to the control unit 16. The control unit 16 drives the display medium 20 based on an input from the CPU 14 and displays an image.
[0053]
Next, display control processing for preventing unauthorized copying by the CPU 14 will be described with reference to the flowchart of FIG.
[0054]
In step 100, it is determined whether the optical sensor 12 has detected a light amount equal to or greater than a predetermined value.
[0055]
If it is determined that it has been detected, it is determined in step 102 whether the detected light is moving at a constant speed in a fixed direction. If an affirmative determination is made here, the detected light is determined to be scan light by the image input device.
[0056]
Steps 100 and 102 will be described in detail. When the sensor element of each optical sensor 12 detects a light source having a light amount equal to or greater than a predetermined value, the timing is captured by the CPU 14.
[0057]
FIG. 8A is a diagram showing a relationship between the optical sensors 12 arranged in an L shape and the movement of the scan light. The dotted line in the figure is the passing position when the scan light 30 moves at an angle of θ with respect to the scan line direction of the display medium 20 (the arrangement direction of the scan electrodes). The moving direction and the moving speed of the scanning light 30 are obtained from the position of each optical sensor 12 and the timing of the detection by the CPU 14, whereby it can be determined whether the detected light is moving at a constant speed in a certain direction. .
[0058]
An example of a method for deriving the moving direction and the moving speed of the scan light 30 will be described with reference to FIG. As shown in the figure, when the optical sensors 12a, 12b, 12c, 12d, and 12e are arranged, and the scan light moves as indicated by a dotted line, the arrangement interval of each optical sensor is 1 and the scan light display medium 20 Is the angle (moving direction) with respect to the scanning line direction, and Δt is the difference between the detection time of the optical sensor 12a and the detection time of the optical sensor 12b.₁The difference between the detection time of the optical sensor 12a and the detection time of the optical sensor 12c is Δt₂If the moving speed v at this time is, the following equation is established.
[0059]
l · cos θ = vΔt₁
l · sin θ = vΔt₂
Therefore, from the above equation, the moving direction θ is
θ = tan^-1(Δt₂/ Δt₁)
The moving speed v is obtained by substituting the value of θ into one of the above two equations.
[0060]
Thereby, the first moving direction and the moving speed are obtained.
[0061]
Also, the second moving speed and the moving direction are determined in the same manner as described above from the difference between the detection time of the optical sensor 12a and the detection time of the optical sensor 12c, and the difference between the detection time of the optical sensor 12a and the detection time of the optical sensor 12e. If the change is within a predetermined value as compared with the first moving speed and moving direction obtained previously, it is determined that the detected light is moving in a certain direction at a constant speed. After the determination, the average value of the moving speed and the average value of the moving direction obtained by the above processing are calculated, and these average values are used in the subsequent processing as the moving speed and the moving direction of the scan light.
[0062]
If it is determined that the light is moving in a certain direction at a certain speed, it is determined in step 104 whether the image displayed on the display medium 20 is copy-prohibited. This determination is made based on the identification data attached to the display data used for display.
[0063]
If the displayed image is prohibited from being copied, in step 106, data is read from a memory (not shown) connected to the CPU 14, and it is determined whether the display medium 20 is in a matrix drive system. You. That is, it is determined that partial erasure and change can be performed with the matrix driving method. In the present embodiment, since the display medium 20 is of the matrix drive type, the determination is affirmative.
[0064]
Next, at step 108, it is determined whether or not the moving direction of the light detected by the optical sensor 12 is within a predetermined angle with respect to the scanning line direction, for example, whether or not | θ | ≦ 15 °. If the determination is affirmative, control is performed so as to partially delete the displayed image or change the display.
[0065]
Here, the scan light moving obliquely to the scan line direction of the display medium 20 partially covers the information line direction (the arrangement direction of the information electrodes) of the display medium 20 as shown in FIG. If the displayed image is erased or changed to cope with it, the copied image is only hatched, and the content may be readable when the entire page is copied. Therefore, in the case of light moving in an oblique direction (other than the scanning line direction), it is necessary to change or erase the entire surface at once. Here, a threshold value of the angle (θ in FIG. 8) of the scan light with respect to the scan line direction is set, and if it is within the range of the threshold value, the moving direction of the scan light is determined to be the scan line direction. If it is out of the range, it is determined that the moving direction is other than the scanning line direction. In the present embodiment, the threshold is set to the scanning line direction ± 15 °, and the other directions are regarded as other than the scanning line direction.
[0066]
If it is determined in step 108 that the moving direction is the scanning line direction, partial erasure and change can be performed, so that the light is detected by the moving speed and the sensor 12a previously obtained in step 110. The scan position (the irradiation position of the scan light, that is, the position at which the image is read) is predicted based on the product of the time elapsed and the elapsed time with reference to the time point. , A message or an advertisement is partially displayed instead of the display image). The control unit 16 controls driving of the display medium 20 based on control signals and data from the CPU 14.
[0067]
The process of step 112 will be specifically described. Partial erasure or partial change is performed in accordance with the scan position predicted in step 110. At this time, since the processing is performed in the scan line direction, the partial erase / change position moves at the same speed as the scan light moves. Let it. If the scan position has moved, the display is restored to the original display, except for the area of the changed area other than the area to be changed including the moved scan position (step 112).
[0068]
For example, in the case of a display medium having 640 segment lines, if the threshold value of the angle of the scan light with respect to the scan line direction is ± 15 °, the scan light is irradiated. The number of common lines is 640 tan15 ° lines (about 180 lines). Therefore, in the present embodiment, the width of the partial erase or change is set in advance to about 200 lines in consideration of the error between the derived scan position and the actual scan position, and the width of the width is changed along with the movement of the scan position. Partially erase or change the area.
[0069]
In the case of partial erasure, the displayed image may be erased in a single color such as white or black, and in the case of partial erasure, a warning message such as "copy prohibited" or "copy restricted" or a corporate message. May be displayed. When displaying a warning message or an advertisement, the CPU 14 outputs an address for reading out the warning display data or the advertisement display data from the VRAM 18 to the control unit 16, and displays a partial display image corresponding to the scan position of the display medium 20. The control signal is output so as to be changed to a warning message or an advertisement. The control unit 16 controls driving of the display medium 20 based on control signals and data from the CPU 14.
[0070]
Hereinafter, a specific example in the case of partial modification will be described. FIG. 10 is a diagram showing a state where confidential matters are displayed on the display medium 20. As shown in FIG. 11, as the scan position is moved, a predetermined area including the scan position (200 lines including the 180 lines at the scan position) is partially changed. The change area also moves as the scan position moves. FIG. 12A is a diagram showing a display state of the display medium 20 after the copy processing, and FIG. 12B is a diagram showing a copy result on the display medium 20. As shown, the display of the display medium 20 has been restored to its original state, but a warning message and an advertisement different from those of the display medium 20 are displayed in the copy result.
[0071]
After step 112, the process returns to step 100.
[0072]
If a negative determination is made in step 106 or step 108, a control signal or data is output to the control unit 16 in step 114 so that the entire surface is collectively erased or a message or an advertisement is displayed all in one. The control unit 16 controls driving of the display medium 20 based on control signals and data from the CPU 14.
[0073]
In the case of the entire batch erasure, the display image may be batch-erased in a single color such as white or black. In the case of the batch erasure, the “copy prohibited”, “copy restriction” It is possible to display a warning message such as Further, an advertisement or the like may be displayed together with the warning message or alone.
[0074]
FIG. 13 shows a specific display example when the entire surface is changed collectively. FIG. 13A shows a display state of the display medium 20 in a case where the display medium 20 on which the confidential matter is displayed as shown in FIG. Indicates a copy result on the display medium 20.
[0075]
Next, in step 116, it is determined whether or not the irradiation of the scan light has been completed. If it is determined that the processing has not been completed, the display on the display medium 20 is maintained as it is. If it is determined that the display has been completed, in step 120, a control signal for restoring the display state of the display medium 20, which has been completely erased or changed, to the original state, and an address for reading display data from the VRAM 18. Is output to the control unit 16 to restore the display. For example, the display medium 20 whose display has been changed as shown in FIG. 13A is restored to the original display state as shown in FIG.
[0076]
If a negative determination is made in steps 100, 102, and 104, the process returns to the standby state.
[0077]
As described above, when the scan light moving at a constant speed in the fixed direction is detected, the image displayed on the display medium 20 is completely or partially erased or changed, so that the copy is surely performed. Can be prevented.
[0078]
In the above-described first embodiment, an example of the display device in which the display medium 20 and the optical sensor 12 are provided inseparably from the CPU 14, the control unit 16, and the VRAM 18 has been described. A second embodiment in which the sensor 12 is provided so as to be separable from the CPU 14, the control unit 16, and the VRAM 18 will be described.
[0079]
FIG. 14 is a schematic configuration diagram of a display device according to the second embodiment to which the present invention is applied. The same parts as those in the above embodiment are denoted by the same reference numerals, and detailed description will be omitted.
[0080]
The illustrated display device 80 includes a drive unit 50 including the CPU 14, the control unit 16, and the VRAM 18. The display unit 80 includes a reflective display medium 20, an optical sensor 12, an erasure drive unit 62, and a battery. A separate display unit 60 constituted by a photo 64 and a photovoltaic unit 66 is connected to the drive unit 50 via a connector 70.
[0081]
When the separate display unit 60 is used separately from the drive unit 50, the erasing drive unit 62 detects scan light that moves at a constant speed in a fixed direction by the optical sensor 12 instead of the CPU 14 and the control unit 16. In such a case, the minimum necessary control for simultaneously erasing the entire image displayed on the display medium 20 is performed.
[0082]
The battery 64 is connected to the erasing drive unit 62, stores energy enough for the erasing drive unit 62 to perform at least one erasure, and supplies energy to the erasing drive unit 62.
[0083]
The photovoltaic power generation unit 66 is connected to the erasure drive unit 62, performs photovoltaic power generation using the received light, and supplies the erasure drive unit 62 with energy obtained by the photovoltaic power generation. For example, when the display medium 20 is repeatedly separated and used so that the capacity of the battery 64 is not sufficient to allow the erase drive unit 62 to perform control for erasure, the erase drive unit 62 replaces the battery 64. The required energy can be obtained without the need.
[0084]
Hereinafter, the display control processing according to the present embodiment will be described.
[0085]
First, in a state where the separation display unit 60 is not separated, the CPU 14 outputs an address for reading display data from the VRAM 18 and a control signal to the control unit 16. The control unit 16 drives the display medium 20 based on an input from the CPU 14 and displays an image. Further, the CPU 14 outputs the identification data added to the display data to the erasing drive unit 62. The erasing drive unit 62 is provided on the separation display unit 60 side and stores the input identification data in a memory (not shown) connected to the erasing drive unit 62.
[0086]
Next, a display control process for preventing unauthorized copying by the CPU 14 will be described with reference to the flowchart of FIG.
[0087]
In step 200, it is determined whether or not the separated display unit 60 (display medium 20) is in the separated state. This determination is made based on whether or not the separate display unit 60 is electrically connected by the connector 70. If it is determined that the document is in the separated state, the display control process for preventing unauthorized copying is not performed on the driving unit 50 side.
[0088]
If it is determined that the state is not the separation state, the processing of step 202 and subsequent steps is executed. The processing after step 202 is the same as in the above-described first embodiment, and a description thereof will not be repeated.
[0089]
Next, a display control process for preventing unauthorized copying by the erasing drive unit 62 will be described with reference to the flowchart of FIG.
[0090]
In step 300, it is determined whether or not the separated display unit 60 (display medium 20) is in the separated state. This determination is made based on whether or not the separate display unit 60 is electrically connected by the connector 70. If it is determined that the document is not in the separation state, the display control process for preventing unauthorized copying is not performed by the erase driving unit 62.
[0091]
If it is determined that it is in the separated state, it is determined in step 302 whether the optical sensor 12 has detected a light amount equal to or greater than a predetermined value.
[0092]
If it is determined that the light has been detected, it is determined in step 304 whether the detected light is moving in a certain direction at a certain speed. If an affirmative determination is made here, the detected light is determined to be scan light by the image input device.
[0093]
Note that details of the processing of step 302 and step 304 are the same as those of the above-described first embodiment, and a description thereof will not be repeated.
[0094]
If it is determined in step 304 that the light is moving at a constant speed in a certain direction, it is determined in step 306 whether or not the image displayed on the display medium 20 is copy-prohibited. This determination is made based on the identification data stored in the memory (not shown). If an affirmative determination is made in step 306, the drive of the display medium 20 is controlled so that the image displayed on the display medium 20 is entirely erased in step 308.
[0095]
The entire batch erasing is the same as in the first embodiment described above, and a description thereof will be omitted.
[0096]
If a negative determination is made in steps 302, 304, and 306, the process for preventing copying thereafter is not performed, and the process returns to step 300.
[0097]
As described above, even when the display medium 20 is used separately from the driving unit 50, if the scan light that moves at a constant speed in a certain direction is detected, the image displayed on the display medium 20 is entirely displayed. As such, unauthorized copying can be prevented.
[0098]
The display medium is not limited to the display medium described in the first and second embodiments, and may be, for example, a semi-reflective display medium instead of a reflective type. Further, even when the display medium is driven not by matrix driving but by another driving method, illegal copying is prevented.
[0099]
Furthermore, the display device of the present invention is not limited to the above embodiment, and can be appropriately changed without departing from the gist of the present invention.
[0100]
【The invention's effect】
As described above, according to the present invention, when light emitted to a display medium such as electronic paper and moving at a constant speed in a certain direction is detected, an image displayed on the display medium is erased or changed. As a result, the confidential data displayed on the display medium can be protected from unauthorized copying.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a display device according to a first embodiment.
FIG. 2 is a diagram showing an arrangement state of an optical sensor.
FIG. 3 is a diagram showing another example of the arrangement of the optical sensor.
FIG. 4 is a diagram showing another example of the arrangement of the optical sensor.
FIG. 5 is a diagram showing another example of the arrangement of the optical sensor.
FIG. 6 is a diagram showing another example of the arrangement of the optical sensors.
FIG. 7 is a flowchart illustrating a display control process for preventing unauthorized copying by a CPU according to the first embodiment.
8A is a diagram showing a relationship between an optical sensor arranged in an L-shape and the movement of scan light, and FIG. 8B is a method for deriving a scan direction and a scan speed of scan light. FIG.
FIG. 9 is a diagram illustrating a state in which an image displayed on a display medium is partially changed when scan light is emitted obliquely to a scan line direction of the display medium.
FIG. 10 is a diagram showing a state where confidential matters are displayed on a display medium.
FIG. 11 is a diagram showing a state in which an image displayed on a display medium has been partially changed.
12A is a diagram illustrating a display state of a display medium after a copy process, and FIG. 12B is a diagram illustrating a copy result on the display medium.
FIG. 13 is a diagram showing a state in which the image displayed on the display medium has been changed all at once.
FIG. 14 is a schematic configuration diagram of a display device according to a second embodiment.
FIG. 15 is a flowchart illustrating a display control process for preventing unauthorized copying by a CPU according to the second embodiment.
FIG. 16 is a flowchart illustrating a display control process for preventing unauthorized copying by an erasing drive unit according to the second embodiment.
[Explanation of symbols]
10,80 display device
12 Optical sensor
14 CPU
16 control unit
18 VRAM
20 Display media
22 Display
24 Common Driver
26 segment driver
50 drive unit
60 Separate display
62 erase drive
64 battery
66 Light generation unit

Claims (14)

A reflective or semi-reflective display medium;
Storage means for storing display data;
Detecting means for detecting light that is irradiated on the display medium and moves at a constant speed in a certain direction,
While controlling the driving of the display medium so that an image is displayed on the display medium based on the display data stored in the storage means, and when the light is detected by the detection means, Display erasure control means for controlling the drive of the display medium so that the image displayed on the display medium is erased or changed,
A display device including: The display medium is a display medium in which scanning electrodes and information electrodes are arranged so as to be orthogonal,
The display erasing control unit determines a moving direction of the light detected by the detecting unit when the light is detected by the detecting unit, and the moving direction is determined with respect to an arrangement direction of scanning electrodes of the display medium. When the angle is less than the predetermined angle, the driving of the display medium is controlled so that an image displayed in a predetermined area including the light irradiation position on the display medium is erased or changed, and the moving direction is displayed on the display medium. The drive of the display medium is controlled so that the entire surface of the image displayed on the display medium is collectively erased or changed when the angle is equal to or more than a predetermined angle with respect to the arrangement direction of the scanning electrodes of the medium. The display device according to the above. When the light is detected by the detection means, the display erasure control means obtains a light irradiation position on the display medium based on the detection by the detection means, and determines a light irradiation position within a predetermined area including the obtained irradiation position. 2. The display device according to claim 1, wherein driving of the display medium is controlled so that an image displayed on the display medium is deleted or changed. The display erasing control unit drives the display medium so as to restore a display state before erasure or before change to an area other than a predetermined area including a current irradiation position among the erased or changed areas. 4. The display device according to claim 3, wherein the display device is controlled. The display device according to claim 1, wherein the display medium has a memory property. The display device according to claim 1, wherein the display medium and the detection unit are provided so as to be separable from the storage unit and the display erasure control unit. In the display medium,
In a state where the display medium and the detection unit are separated from the storage unit and the display erasure control unit, when the light is detected by the detection unit instead of the display erasure control unit, the display is performed on the display medium. Erasing control means for controlling the driving of the display medium such that the image being erased is provided,
A battery in which the erasing control means stores energy capable of performing at least one erasing;
The display device according to claim 6, further comprising: A power generation unit that is provided separably from the storage unit and the display erasure control unit together with the display medium, the detection unit, the erasure control unit, and the battery, and that performs photovoltaic power generation using the received light. Have
The display device according to claim 7, wherein the erasing control unit controls driving of the display medium using energy obtained by photovoltaic power generation of the power generating unit. The display data stored in the storage means is provided with identification data indicating whether an image displayed based on the display data is copy-prohibited,
The display erasing control unit or the erasing control unit is configured to perform the display when the light is detected by the detection unit and the identification data of the display data used to display the display medium is copy-prohibited. The display device according to any one of claims 1 to 8, wherein driving of the display medium is controlled such that the image displayed on the medium is deleted or changed. The display device according to claim 1, wherein the detection unit is arranged in a display area of the display medium. The display device according to claim 1, wherein a plurality of the detection units are provided. The display device according to claim 1, wherein the detection unit is disposed in an L-shape at least at one corner of the display medium along a vertical direction and a horizontal direction. The display erasing control means, when changing the display of the display medium, replaces the display with the display data stored in the storage means, and displays the predetermined message or advertisement so as to display a predetermined message or advertisement. The display device according to claim 1, wherein the display device controls driving. A determining step of determining whether light that is irradiated on a reflective or semi-reflective display medium and moves at a constant speed in a certain direction has been detected,
A control step of controlling the drive of the display medium such that an image displayed on the display medium is erased or changed when it is determined that the light is detected by the determination step,
And a copy protection method.

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