JP2006202030A - Display system and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To drive an electronic paper (EPD (Electrophoretic Display)) through the supply of power from a higher-level device, thereby eliminating a power supply, and achieving product miniaturization. <P>SOLUTION: A display device using an EPD (electrophoretic display) method, which consumes little electricity and which is capable of keeping an image displayed even after the supply of electricity is cut off, has no power supply. As the display device is driven while receiving the supply of power from an information device (digital camera, digital video camera, personal computer, PDA, cellphone), control is executed so that the amount of electricity consumed by the information device is minimized. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display system for displaying an image by transmitting image data and supplying power to the display device from the information device and the display device connected via a cable capable of supplying power, and a control method thereof. The purpose is to provide.

  Currently, there are liquid crystal displays, CRTs using cathode ray tubes, plasma displays, and the like as display devices.

  These display devices always require power supply, and power supply connected to a household power outlet or power supply from a built-in battery is indispensable.

  As typical display devices used outdoors, there are digital cameras, digital video cameras, mobile phones, notebook personal computers, personal digital assistants (PDAs), and the like, which are used with a built-in battery. There are many cases.

  On the other hand, there is a power supply system based on the USB standard or the IEEE 1394 standard as a form of receiving power from an external apparatus without having a built-in battery in the own apparatus.

  This is a method generally called a “bus-powered device”, and is a method of operating by constantly receiving power from an external device connected by a cable.

As another conventional example, for example, Patent Document 1 and Patent Document 2 can be cited.
JP 2002-244620 A JP 2002-281423 A

  However, since the power supply time of the built-in battery is limited, the total use time is limited and it is difficult to always display on the display device.

  As a result, measures are taken to minimize power consumption, such as automatically turning off the display device and displaying with reduced brightness.

  In addition, even when power is supplied from an external device, the external device itself is driven by a built-in battery, and if power is supplied from the battery, there is a limit to the power supply time and power consumption like a display device. However, it is difficult to supply sufficient power to a device having a high value.

  Therefore, the present invention is a display device that uses an EPD (display using an electrophoretic phenomenon) system that can display an image even after the power supply is cut off and has a very low electricity consumption. The display to minimize the amount of electricity consumed on the information device side while receiving power from the information device (digital camera, digital video camera, personal computer, PDA, mobile phone) without having a power supply The purpose is to provide a system.

  In order to solve the above-described problem, in the present invention, in an information device having a power source and a display device not having a power source, means for connecting via an interface capable of supplying power, and image data from the information device to the display device Means for supplying power during transmission, means for not supplying power when image data is not transmitted from the information device to the display device, and power supply when image data transmission from the information device to the display device is started. Means for stopping the power supply from the information device after the set time has elapsed after the transmission of the image data, and supplying power together with the start of image data transmission from the information device to the display device. It has means for making a power supply stop request to the storage device and stopping power supply from the information device in response to the stop request. To.

  As described above, according to the present invention, in a display device using an EPD (display using an electrophoretic phenomenon) system in which electricity consumption is extremely low as a display device and image display can be continued even after power supply is cut off. The display device itself does not have a power supply, and while receiving power from the information device (digital camera, digital video camera, personal computer, PDA, mobile phone), the power consumption on the information device side is minimized. It is possible to provide a display system.

  In this embodiment, image data to an EPD display device is connected to an information device such as a digital camera, a digital video camera, a personal computer, a PDA, a mobile phone, a printer / multifunction device, and a cable capable of supplying electricity. An operation flow of control and image display control from the start to the end of transmission and power supply will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of the present invention.

  In FIG. 1, the system includes a display device 10, an information device 30 (a digital camera 31, a digital video camera 32, a personal computer (hereinafter abbreviated as a PC) 33, a PDA 34, a mobile phone 35, and a printer / multifunction device 36). Yes.

  In the figure, reference numeral 40 denotes a cable that can transmit image data and distribute power, and the ideographic device 10 and the information device 30 can be connected by the same cable.

  The information device 30 is equipped with a non-volatile memory. In addition to still image data represented by JPEG, moving image data represented by MPEG is stored in the non-volatile memory, and the data is cabled. It is possible to transmit to the display device 10 via 40.

  An operation for transmitting image data is performed from an operation unit (not shown) in the information device 30 and can also be performed from an operation unit (not shown) in the display device 10.

  A configuration of the display device 10 will be described with reference to FIGS. 2, 3, and 4.

  FIG. 2 shows an EPD (display using an electrophoretic phenomenon) type display unit.

  This encapsulates charged toner between two plastic films and electrically changes the in-plane distribution of the toner to form an image.

  The display unit 20 includes a TFT unit 22, an adhesive layer 23, an encapsulated display medium 24, and a resin material 26.

  When the TFT unit 22 applies an electric field to the display medium 24, the charged toner in the display medium 24 is electrostatically adsorbed on one of the electrodes according to the polarity and covers the surface thereof.

  Here, one electrode is black with a small area and the other is white with a large area, thereby generating a contrast and forming an image.

Note that, after the image is formed, the toner adsorbed on the electrode surface maintains its state even when the electricity is turned off, so that the display image is non-volatile. (Details of electrophoresis will be described with reference to FIG. 4.)
FIG. 3 shows a method for realizing the TFT unit 22, which is a matrix type in which a switching element is added to each picture element arranged in the display area described in “Special Registration 02547314 Liquid Crystal Display Device Driving Circuit”. The present invention relates to a driving circuit of a display device.

  FIGS. 3A and 3B are a circuit configuration diagram showing a basic block circuit of a matrix type display device, and timing waveform diagrams showing an example of signal waveforms applied to row / column electrodes.

  Reference numeral 11 denotes a display panel, in which a switching transistor 11-c is formed at each intersection of a row electrode 11-a and a column electrode 11-b arranged in a plurality in orthogonal directions, and the gate electrode of the switching transistor 11-c is a row electrode. 11-a, the source electrode is connected to the column electrode 11-b, and the drain electrode is connected to a display pixel electrode arranged in a matrix.

  A row electrode driving circuit 12 outputs a scanning pulse such as Ps shown in FIG. 3B to each row electrode.

  A column electrode drive circuit 13 outputs a data waveform corresponding to the display content such as Pd shown in FIG. 3B to each column electrode.

  Reference numeral 14 denotes a control circuit for operating the row and column electrode drive circuits.

  In such a display device, when a row having a display area is selected by the scanning pulse Ps and the switching transistor 11-c is turned on, a voltage corresponding to that row of the data waveform Pd is displayed via the switching transistor 11-c. A voltage is applied to the pixel electrode, and a voltage is applied to the electronic display medium 11-d located between the display pixel electrode and the counter electrode facing it.

  Next, when this row is not selected, the switching transistor is turned off, and the display picture element electrode and the column electrode are separated, so that the voltage applied to the electronic display medium 11-d remains as it is without being affected by the data waveform. This is sequentially repeated in the row direction to obtain a clear display pattern without crosstalk.

  The series of diagrams in FIG. 4 illustrates the mechanism of the display medium 24.

  FIG. 4 a shows an electrophoretic display 130.

  The binder 132 includes at least one capsule 134 filled with a plurality of particles 136 and a dye suspending fluid 138.

  In the embodiment, the particles 136 are titania particles.

  When a suitable polarity DC electric field is applied to the capsule 134, the particles 136 move to the viewing surface of the display and scatter light.

  If the applied electric field is reversed, the particles 136 move to the back of the display and the visual surface of the display appears dark.

  FIG. 4 b shows another electrophoretic display 140.

  The display includes a first set of particles 142 and a second set of particles 144 within a capsule 141.

  The first set of particles 142 and the second set of particles 144 have contrasting optical properties.

  For example, the first set of particles 142 and the second set of particles 144 may have different electrophoretic mobilities.

  In addition, the first set of particles 142 and the second set of particles 144 may have a contrasting color.

  For example, the first set of particles 142 can be white and the second set of particles 144 can be black. The capsule 141 further includes a substantially transparent fluid.

  Capsule 141 has electrodes 146 and 146 'deposited adjacent to capsule 141.

  Electrodes 146, 146 'are connected to voltage source 48 and may provide an alternating current (AC) or direct current (DC) electric field to capsule 441.

  In applying an electric field to the electrodes 146, 146 ′, the first set of particles 142 moves toward the electrode 146 ′, while the second set of particles 144 moves toward the electrode 146.

  FIG. 4 c shows a suspended particle display 150.

  Suspended particle display 150 includes acicular particles 152 in a permeable fluid 154.

  The particles 152 change direction when an AC electric field is applied to the electrodes 156, 156 '.

  When an AC electric field is applied, the particles 152 are oriented perpendicular to the display surface and the display appears transparent.

  When the AC field is removed, the particles 152 are randomly oriented and the display 150 appears opaque.

  The electrophoretic displays provided in FIGS. 4a-4c are merely examples, and other electrophoretic displays can be used in accordance with the present invention.

  Other examples of electrophoretic displays are described in co-pending US patent application serial numbers 08 / 935,800 and 09 / 140,792, which are hereby incorporated by reference.

  In another detailed embodiment, the display medium may include a plurality of heavy chromium spheres as shown in FIG. 4d.

  The heavy chromium sphere 160 typically includes a first color positively charged hemisphere 162 and a second color negatively charged hemisphere 164 in the liquid medium 166.

  When applying an electric field in the sphere 160 through the pair of electrodes 168, 168 ′, the sphere 160 rotates to display one color of the two hemispheres 162, 164.

  The display device 10 is an EPD type display device described with reference to FIGS. 2, 3, and 4, and the toner adsorbed on the electrode surface after the image formation and after the electrical supply is cut off maintains its state. The display image is maintained.

  The display device 10 includes an encapsulated display medium 24 and a drive circuit unit 22 that drives the medium.

  The activation circuit unit 22 includes a control circuit 14 for outputting corresponding signals to the row electrode driving circuit 12 and the column electrode driving circuit 13, respectively. The circuit performs a boosting process on the voltage input from the power source. Thus, a plurality of types of voltages are generated, and the voltage applied to the pixel electrodes is controlled to perform multi-tone display.

  Further, when a built-in battery is used as the supplied power, processing such as adjusting the operating voltage according to the remaining amount of the battery is also performed for power saving.

  In the case of a liquid crystal display device, power supply is always required to maintain the display image. However, in the case of an EPD display device, the display image is maintained even if power supply is stopped. Taking advantage of the feature, a method of receiving power supply only when power supply is necessary and stopping the power supply after image display is completed will be described.

  In this embodiment, as a method for controlling the supply and stop of power from the information device, a method for unilaterally controlling the supply and stop of power from the information device to the display device will be described.

  When image data is transferred from the information device to the display device via a cable, power supply is started from a predetermined time before the data transfer is started, and power is supplied after a predetermined time has elapsed after the transfer of all image data. Shut off.

  Here, the predetermined time before the start of image data transfer refers to the time required for preparations such as erasure of the image previously displayed on the display device and image data transfer acceptance processing, and the capability of the display device. From the time information calculated in advance.

  The predetermined time after the end of the image data transfer indicates the time when the display of all the image data is completed on the display unit of the EPD system, and the time information calculated in advance from the capability of the display device. decide.

  The predetermined time before and after the image data transfer is a time that takes into account the recovery time in the event of an image data transfer error or display error.

  The operation flow of the information device 30 described above will be described with reference to FIG.

  First, the information device 30 and the display device 10 are connected using the cable 40.

Then, the operation unit of the information device 30 selects image information to be displayed on the display device 10 and performs a display operation. (Step 101)
The information device 30 starts supplying power to the display device 10. (Step 102)
The information device 30 gives an operation instruction to the display device 10 such as start of image data transfer. (Step 103)
Time measurement is started on the information apparatus side from the operation instruction in step 103, and after a predetermined time has elapsed (step 104), transfer of the image data selected in step 101 is started. (Step 105)
After the transfer of the image data (step 106), time measurement is started on the information device side, and after a predetermined time has elapsed (step 107), the power supply is stopped. (Step 108)
The operation flow of the display device 10 when the operation of the information device 30 of FIG. 5 is performed will be described with reference to FIG.

First, power supply from the information device 30 is started. (Step 201)
Next, upon receiving an operation instruction from the information device 30, preparation for transfer acceptance of the image data and, if necessary, an erasing process of the image currently displayed on the display unit are performed. (Step 202)
The timing at which the displayed image is erased differs depending on the device, but it may be erased at the timing of step 202 as shown in this figure, or a new display is performed at step 205 described later. Erasing may be performed immediately before.

After completion of preparation for receiving image data in step 202, reception of image data from the information device 30 is started. (Step 203)
When the reception of all the image data is completed in step 204, the received image data is driven by the control circuit 14, the row electrode drive circuit 12, and the column electrode drive circuit 13 to display an image on the display panel 11. (Step 205)
After the display is completed in step 205, the power supply from the information device 20 is stopped, and thus the above operation flow is completed. (Step 206)
As described above, in this embodiment, since the display device 30 is operated in consideration of the time required from the transmission / reception of image data to the completion of display, the power is not shut down on the display panel 11 before the display of the image is completed. Explains the case.

  If the power is cut off from the information device 30 before the display on the display panel 11 is completed due to some trouble, the phenomenon that the image data transferred from the information device 30 is not displayed occurs. Assuming the case, even if the screen of the display panel is erased in step 202 or an error is displayed on the display panel 11 using the electricity stored during power supply at the timing of step 206 Suppose it is good.

[First Example]
In the first embodiment, the information device 30 is an information device such as a digital camera, a digital video camera, a personal computer, a PDA, or a mobile phone. However, the information device 30 has a nonvolatile memory and can store image data. Any type is acceptable.

  In addition, the information device may be a printer, a copy / scanner / printer / FAX multifunction device, and the print image is not printed on paper but transferred to the display device 10 connected via the cable 40 for display. Also good.

  It is assumed that the image data transferred from the information device 30 to the display device 10 may be image format data such as a TIFF format or a bitmap format in addition to a JPEG format image.

  Detailed description of the JPEG format, TIFF format, and bitmap format will be omitted in this embodiment.

  As described above, according to the present invention, the display device uses a display device that uses an EPD (display using an electrophoretic phenomenon) system that can display an image continuously even after the power supply is cut off. And providing a system for performing display processing while receiving power from an information device (digital camera, digital video camera, personal computer, PDA, mobile phone) without having a power supply for the display device itself. With the goal.

[Second Example]
In the first embodiment, the method of unilaterally controlling the power supply from the information device to the display device and stopping the power supply has been described. However, in the second embodiment, a power supply stop request is sent from the display device to the information device. The case where it performs with respect to an apparatus is demonstrated.

  The second embodiment will be described with reference to the operation flowcharts of FIGS.

  The operation flow of the apparatus in the second embodiment is similar to the operation flow of FIGS. 5 and 6 of the first embodiment, but the points different from the first embodiment are shown in FIG. Step 301 and Step 302 in FIG. 7 and Steps 401 and 402 in FIG. 8, and other operations are the same as those in the first embodiment.

  In step 202 in FIG. 8, after the display device receives an operation instruction such as the start of image data transfer, the display device starts transfer of image data from the display device to the information device in step 401 in FIG. Make a request.

  After receiving the request at step 301 in FIG. 7, the information apparatus starts transferring image data at step 105 in FIG.

  Further, after the cover processing of the image data is completed in step 205 in FIG. 8, the display device issues a power supply stop request to the information device in step 402 in FIG.

  After receiving the request at step 302 in FIG. 7, the information device stops power supply at step 108 in FIG.

  As described above, the second embodiment is intended to determine the transfer timing of image data and the stop timing of power supply on the display device and make the same request from the display device to the information device.

Block diagram showing forms of information device and display device Cross section of electronic display (A) Matrix type display device with a switching transistor added in the TFT implementation method (block diagram) (B) Matrix display device with a switching transistor added in the TFT implementation method (drive waveform diagram) a partial cross-sectional view of electronic display medium b partial cross-sectional view of electronic display medium c partial cross-sectional view of electronic display medium d partial cross-sectional view of electronic display medium The figure which shows the operation flow of the information equipment The figure which shows the operation flow of the display device The figure which shows the operation flow of the information equipment The figure which shows the operation flow of the display device

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Display apparatus 11 Panel 12 Row electrode drive circuit 13 Column electrode drive circuit 14 Control circuit 20 Display part 22 TFT part 23 Adhesive layer 24 Display medium 26 Resin material 31 Digital camera 32 Digital video camera 33 PC
34 PDA
35 Cellular Phone 36 Printer / Composite Machine 40 Cable 130 Electrophoretic Display 132 Electrode 134 Capsule 136 Particle 138 Dye Suspended Fluid 140 Electrophoretic Display 141 Capsule 142 Particle 144 Particle 146 Electrode 146 ′ Electrode 150 Suspended Particle Display 152 Particle 154 Fluid 156 Electrode 156 ′ electrode 160 heavy chromium sphere 162 hemisphere 164 hemisphere 166 liquid medium 168 electrode 168 ′ electrode

Claims (9)

In an information device that has a power source and a display device that does not have a power source,
Means for connection via an interface capable of supplying power;
Means for supplying power when transmitting image data from the information device to the display device;
Means for not supplying power when image data is not transmitted from the information device to the display device;
Means for supplying power together with the start of image data transmission from the information device to the display device, and stopping the power supply from the information device after a set time has elapsed after completion of transmission of the image data;
When the image data is transmitted from the information device to the display device, power is supplied. After the transmission of the image data is completed, a power supply stop request is issued from the display device to the storage device, and in response to the stop request, the information device A display system comprising means for stopping power supply from the display. The display device according to claim 1,
EPD (display using electrophoretic phenomenon) type display device,
Display means composed of charged toner and TFT (thin film transistor);
A display device comprising means for continuing image display by sustaining charging even after power supply is stopped. In the information device of claim 1,
An information device comprising means such as a digital camera, a digital video camera, a personal computer, a DVD player, a video deck, etc., having a nonvolatile memory and capable of outputting image data. In the interface capable of supplying power according to claim 1,
As means to make a cable composed of image data transmission line and electrical transmission line,
For example, a display system characterized by means of USB standard (Universal Serial Bus), IEEE 1394 standard, or the like.   The display device according to claim 1 is a transflective liquid crystal display device.   The display device according to claim 1 is an organic EL display device.   The display device according to claim 1 is a particle movement type display device.   The particle movement display device is an electrophoretic display device.   The particle movement type display device is a dry toner display device.

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