JP2008026913A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device comprising a combination of a fixed display element and a variable display element. <P>SOLUTION: The display device includes: a first display element having a transmissive mode and a reflective mode and capable of switching display contents; and a reflective second display element displaying a fixed image or fixed characters, with the displayed contents visible through the first display element. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an information display system including, for example, a mobile device and a device that displays arbitrary data given from the device, a display element used in such an information device, a display element driving method, and a display device. More specifically, for example, a system including a wireless terminal and a non-contact IC card, a display element using a cholesteric liquid crystal or the like that maintains a display even when the power is turned off, a driving method thereof, and such a memory property The present invention relates to a display device that uses electronic paper or the like.

  There is a demand for displaying enlarged display information of a mobile phone, a PDA, a digital camera, and the like. One method for this is to enlarge only a part of the terminal screen. Naturally, this method is troublesome such as scrolling because the entire image cannot be viewed at once. As another method, there is a method in which a portable terminal is provided with a short-range wireless communication function such as Bluetooth, infrared, and wireless LAN, and image information is transmitted and displayed wirelessly on a large screen display mounted on a personal computer, a TV, or the like. Alternatively, instead of wireless transmission, an image is transmitted by a wired interface connection function such as USB or IEEE1394 and displayed on a large screen. However, in a mobile environment such as going out, such an enlarged display method is inconvenient for a mobile device because an AC power supply or some kind of battery is required for the display, and the device itself is heavy.

  As a display method in a mobile environment for avoiding this, it is considered to connect a light-weight and low-power magnifying display to a portable terminal. Such attempts have been proposed using lightweight, low power consumption electronic paper. In such a method, since the contact is electrically connected, 1) the size of the mobile terminal is substantially increased in the continuous connection, and 2) deterioration due to fatigue of the electrical contact occurs when connecting only at the time of use. 3) The display is lost after the connection is disconnected, or the battery is mounted on the display to prevent display loss. Battery mounting increases the thickness and weight of the display as well as the inconvenience of battery replacement or battery power feeding. There is a demand for a mobile display system that solves these problems, and that the terminal itself is substantially small, has an enlarged display screen, and is hands-free.

  In addition, there is a demand for printing out arbitrary display information such as a mobile phone, a PDA, a digital camera, etc. at a place of going out or visiting. For this, battery-driven mobile printer devices are on the market, but there are problems of weight and volume, as well as paper and battery replenishment. Instead of such a printer device, it is expected that the display is performed in a state of being separated from the portable terminal, substantially equivalent to a paper print without a printer.

  For such a display, there are the following documents related to a conventional technique using a contact IC card or an RF (radio frequency) tag and a non-contact IC card using short-range radio. Patent Document 1 discloses an IC card that can rewrite the display content of a display unit.

  Patent Document 2, Patent Document 3, and Patent Document 4 disclose an IC card having a power supply for display. In Patent Document 2, a solar cell is disclosed, in Patent Document 3 is a lithium battery, and in Patent Document 4 is an auxiliary power supply. For example, a solar cell is used.

  In Patent Literature 5 and Patent Literature 6, a memory-type display element that can retain display contents even when the power is turned off is used without using an auxiliary power source such as a solar cell. In Patent Document 5, for example, a ferroelectric liquid crystal display element or an electrochromic display element is used, and in Patent Document 6, use of a cholesteric nematic phase transition type liquid crystal is proposed.

In this type of short-range wireless communication, information is generally exchanged with an IC card without power supply from an IC card reader / writer mounted on a fixed terminal. If the card and the writer are close to each other, in principle, display recording power and display information can be given and recorded and displayed. However, there is no convenient display system linked with a mobile terminal using a contactless wireless method, and there are actually several technical reasons such as recording power, voltage, memory retention, recording speed. However, the display on the non-contact IC card has not been realized yet. There is a demand for a convenient display system and electronic paper suitable for mobile use in which arbitrary display information is transmitted from a portable terminal by using such a non-contact wireless method and enlarged display is performed.
Electrophoresis, which is a powerful memory medium, suspends white and black charged fine particles in the white liquid in the capsule and attracts the particles by static electricity, so in principle memory retention, high-speed drive, and low-voltage drive Conflict. It is difficult to use this for powerless recording. Electrochromic is a memory display method that utilizes chemical changes, but has a large write power and is difficult to write wirelessly. As for the memory liquid crystal, the ferroelectric memory liquid crystal medium has a high recording speed, but since the polarizing film is used, the brightness in the reflected white display is insufficient and the display disappears due to a mechanical shock. is there.

  As the memory liquid crystal, there is a cholesteric nematic phase transition type liquid crystal element proposed in Patent Document 6 described above. This material utilizes light scattering properties, but has a problem that the contrast is low and a bias voltage is necessary to keep the display stable.

  In contrast, cholesteric liquid crystals (including chiral nematic liquid crystals) have selective reflectivity that selectively reflects light of a certain wavelength, reflect light wavelengths according to the layer pitch of the liquid crystal, and exhibit a single color. . Therefore, in order to increase the number of colors, a laminated structure as proposed in Patent Document 7 has been proposed.

  FIG. 1 shows a conventional example of a liquid crystal element having a laminated structure using a cholesteric liquid crystal. In this figure, three layers of liquid crystals 204, 205, and 206 are inserted between upper and lower substrates 201 and bonded through transparent electrodes 202, respectively, to form a liquid crystal element. There are many, there is much noise light, and the contrast of a display falls. There are many constituent members, and there is a problem that the device becomes expensive.

  That is, the cholesteric liquid crystal exhibits a certain single color, and when two liquid crystals are mixed, they are easily mixed and cannot reflect a desired color. When two or more liquid crystals are mixed, they are in an intermediate color or non-reflective state. As a method of separating liquid crystal, there is also a capsule structure in which the liquid crystal is enclosed in a capsule, but it is preferable for use in a display device because it causes a decrease in contrast and an increase in driving voltage due to the influence of the interface and thickness of the capsule. In addition, there is a problem that it is difficult to arrange a desired capsule in a desired pixel.

  Next, problems with a power supply circuit when such a cholesteric liquid crystal is used in a non-powered display device such as a non-contact type IC card or electronic paper will be described. Generally, in a non-contact non-contact IC card or the like, for example, a display power is received together with data from a portable terminal or an IC card reader / writer, etc. by short-range wireless, and the display is used. The value of power that can be used is small, and it is necessary to limit the current to the power supply circuit, for example.

  In particular, the cholesteric liquid crystal requires two types of drive waveforms having different peak values in order to drive the planar state and the focal conic state as two stable states as described later. In addition, the driving voltage for the planar state requires about 40 V, which is considerably higher than other display elements. Therefore, there is a problem that the power supply circuit is expensive. In addition, when a general DC-DC converter is used, a capacitor (μF order) having a large capacitance is required, so that it is extremely difficult to make the power supply circuit within a thickness of about 1 mm. It was.

  FIG. 2 shows a conventional example of drive waveforms for a passive matrix type element. As shown in the figure, the pixel on the selection level line must be applied with a driving voltage to the planar and focal conic states depending on whether the signal line is on or off, and is not selected. It is necessary to apply a voltage that does not change the written state at the time of selection to the pixels on the level line. A commercially available STN liquid crystal driver LSI requires, for example, five types of voltages, and the power supply circuit is expensive. There was also the problem of becoming.

  Next, for example, when the non-contact IC card is operated only by supplying power from the IC card reader / writer, the amount of power supplied varies greatly depending on the distance between the reader / writer and the IC card, for example. For this reason, when the display unit is always operated, the communication distance is remarkably shortened compared to a normal non-contact IC card having no display unit, or the power necessary for the non-contact IC card chip is temporarily insufficient during communication. There was a problem that operation became unstable. For such problems, display control corresponding to the amount of power supply is required.

  The power to drive the passive matrix type cholesteric liquid crystal is relatively small except at startup, and it can operate sufficiently with the power supplied from the weak contactless IC card reader / writer mounted on the PDA. is there. However, in the existing driver LSI, moving image display is premised, and since the impedance at the time of conduction of the final stage transistor is low, a very large instantaneous current (5 to 10 times that in steady operation) flows in a transient state at the time of startup. For this reason, there is a problem in that the existing driver LSI may not be activated even if power several times that in the steady operation is supplied.

  It is extremely disadvantageous in terms of cost to prepare a power supply with a large supply capacity only for start-up, and a weak output reader / writer mounted on a PDA or the like consumes 5 to 10 times the power during steady operation. It is absolutely impossible to supply. For this reason, it is indispensable to develop a control method for stably starting an existing driver LSI with a power supply that is as close as possible to the power consumption during steady operation.

  Further, as described above, the cholesteric liquid crystal requires two types of driving waveforms having different peak values corresponding to the planar driving and the focal conic driving, and the peak values need to be changed depending on the temperature. For this reason, when trying to widen the operating temperature range, the peak value of the planar drive at a high temperature and the peak value of the focal conic drive at a low temperature become close to each other, making it difficult to secure a margin for the peak value. was there. In order to expand the application range of cholesteric liquid crystals, a method for ensuring a margin of peak value in a wide operating temperature range is desired.

  Next, problems of high-speed driving of cholesteric liquid crystal will be described. As described above, there are two types of driving for cholesteric liquid crystal: planar driving and focal conic driving. Generally, an AC pulse voltage is used, but depending on the material of the liquid crystal, a period of approximately 20 ms, that is, 20 ms / line. When writing is performed at a higher speed, there is a problem that the transition to the focal conic state becomes insufficient as shown in FIG. 3, and the contrast is greatly lowered as shown in FIG. If writing at a slower speed, sufficient contrast can be obtained. For example, even on a QVGA size screen (320 × 240 dots), it takes about 5 seconds to complete the writing, and the waiting time until the display is completed increases. There was a problem that it was.

  As a high-speed driving method for solving this problem, a driving method as described below has been developed. In such a method, a wireless method using a weak electromagnetic wave as in the non-contact IC card targeted by the present invention is used. There were various problems in driving. The following is a description of typical high-speed driving methods and their problems, assuming the use of cholesteric liquid crystals.

  Patent Document 8 discloses a writing method named FCR (Focal Conic Reset) method in which after a reset voltage is applied to all scan electrodes for the first time, a selection voltage is sequentially applied to each scan electrode. However, collective reset by selecting all the scan electrodes is not suitable for wireless driving because the power consumption at that time is enormous due to selection of all the scan electrodes. In particular, power consumption is large when transitioning to the focal conic state.

  Also, Patent Document 9 uses a full-scale homeotropic reset method, and the power consumption at the time of reset is very large as described above. For this reason, wireless drive is not feasible.

  The DDS (Dynamic Drive Scheme) method disclosed in Patent Document 10 and the like also has a high scanning speed, but the driving circuit becomes complicated and expensive due to a complicated driving waveform. Furthermore, since the total time until the display state of the pixel is determined (reset period to sustain period) is long, the power consumption is large and it is not suitable for wireless driving.

  Also, the MLA (multiline access) method, which is widely known for STN driving, consumes a large amount of power because it drives a large number of lines at once, and is not suitable for wireless driving. In addition, the drive circuit is complicated and expensive.

  ・ Images with a high spatial frequency, such as a checkerboard pattern, consume significant power, making the above driving method more and more disadvantageous for wireless driving.

  -Afterimage remains in the planar reset.

  Patent Document 11 discloses, for example, a method of detecting a plurality of lines including the same write line data and simultaneously writing to the plurality of lines. However, there is a method for determining the maximum number of lines for simultaneous writing. It is unknown.

  As in the present invention, for example, when driving on a non-contact IC card is handled, high-speed driving up to the μs order is not particularly necessary. A driving method is required.

  Finally, problems of the display device using electronic paper using the cholesteric liquid crystal as described above will be described. In other words, the development of a display device using electronic paper that has the feature that the display does not disappear at least immediately after the power is turned off and the feature that the display content can be arbitrarily rewritten is being developed, Such a conventional apparatus has a problem that it does not have an automatic display function.

That is, as an automatic display device, there is no information on when, from where, how to acquire the data to be displayed, and no information on the display format of the acquired display data, so the display data is automatically displayed according to the acquisition method information. There is a problem that an automatic display device is not provided which automatically enters a standby state after obtaining the image and automatically displaying the image according to the display format information.
No. 7-30384 JP-A-62-242592 JP-A-63-3393 JP 2003-6590 A JP 10-93484 A JP 2000-113137 A JP-A-9-160066 JP 11-326871 A Japanese Patent Laid-Open No. 2002-6287 JP 2002-55327 A Japanese Patent Laid-Open No. 10-20809

  A first object of the present invention is to enable mechanical detachment between, for example, an information display device that does not have a power source and a wireless terminal that sends arbitrary display data and power to the information display device. To provide a display system.

  A second object is to provide a display element that can realize high contrast at a low cost by using a plurality of cholesteric liquid crystals, and a display device using such a display element.

  A third object is to provide a power supply circuit that enables stable operation of the card using various control methods even when the amount of power supplied in the non-contact IC card is small, for example.

  A fourth object is to provide an element driving method and an image display method in which a power consumption is reduced as much as possible in a display device using, for example, a cholesteric liquid crystal.

  The fifth purpose is to store information on how to acquire data to be displayed and information on the display format of display data, automatically acquire data from the outside, display the data, and automatically enter standby mode. And to provide an automatic display device having a wide range of application fields.

  The information display system of the present invention includes a display device and a display data holding device. The display device receives the display means that can continue displaying data even when the power is turned off, the short-range communication means that performs short-range communication to receive any data to be displayed from the outside, and the short-range communication means. Display control means for controlling the display of the display means corresponding to the data.

  The display data holding device includes storage means for holding display data, and transmission means for transmitting display data to the display device side in correspondence with the storage contents of the storage means at least within a short distance range.

  The display device and the display data holding device can also be provided with mechanical detachment means for enabling the detachment of the display device and the display data holding device. It is possible to perform feeding and enlargement display.

  The display element of the present invention, that is, a display element in which liquid crystal is injected between two substrates, includes a partition having a structure for preventing liquid crystals of a plurality of colors injected between the two substrates from contacting each other. .

  In addition, the display device of the present invention has a transmission mode and a reflection mode, displays a first display element whose display contents can be switched, a fixed image or a fixed character, and visually recognizes the display contents through the first display element. A possible reflective second display element.

  The display device of the present invention includes temperature compensation means for changing the peak value of the waveform of each drive voltage corresponding to the planar and focal conic states of the cholesteric liquid crystal, for example, according to the temperature. The display device of the present invention has a coil installed to receive a high-frequency magnetic field from the outside. The coil includes an intermediate tap, and one end of the coil is grounded. A logic power supply means is connected to the resonance capacitor and rectifies the high frequency voltage generated at both ends of the resonance capacitor to give a voltage to a circuit other than the display, and the high frequency voltage between the other end of the coil and the intermediate tap Display power supply means for rectifying and providing a display voltage.

  As a device driving method of the present invention, in a matrix type display device using cholesteric liquid crystal, a part of a scan electrode is set as a selected reset line, a writing line, and a non-selected pause line, respectively. A driving method for applying a write data signal to the signal electrode side while shifting the write line is used.

  Further, as a display element driving method of the present invention, in the matrix type display device as described above, a plurality of lines having the same data pattern to be displayed are detected from a plurality of lines on the display screen. A driving method is used in which the lines are simultaneously selected and the same pattern data is applied to the signal electrode to perform batch writing of the same pattern.

  The display device of the present invention includes, for example, a display unit that can continue to display data even when the power is turned off, a storage unit that stores information about a method for acquiring data to be displayed, and information about a display format of acquired display data. And control means for controlling acquisition of display data from the outside and display of the display data on the display means in accordance with the stored contents of the storage means.

  According to the present invention, a display device is configured using, for example, a cholesteric liquid crystal display element that can continue data display even when the power is turned off, and the display device and a display that supplies power to the display device side together with display data at the same time An information display system is constituted by a data holding device, for example, a portable terminal.

  FIG. 5 is a block diagram showing the principle configuration of the information display system of the present invention. In the figure, the system includes a display device 1 and a display data holding device 2.

  The display device 1 includes, for example, a display unit 3 that can continue to display data even when the power is turned off, a short-distance communication unit 4 that performs short-distance communication in order to receive data to be displayed from the outside, and a short-distance communication unit The display control unit 5 controls the display of the display unit 3 corresponding to the arbitrary data received by the control unit 4.

  The display data holding device 2, for example, the portable terminal, has a storage unit 6 that holds the display data, and a communication unit that transmits display data to the display device 1 side corresponding to the storage content of the storage unit 6 at least within a short distance range. 7.

  Unlike the communication unit 7, the display data holding device 2 is capable of long-distance communication, and further includes a long-distance communication unit for acquiring display data from the outside, and the communication unit 7 is obtained by the long-distance communication unit. Data can also be transmitted to the display device 1 side.

  The display device 1 may further include a mechanical attachment / detachment unit for attaching the device itself to a human body or clothes.

  The display data holding device 2 can further include a display unit having a display area smaller than the display unit 3 on the display device 1 and a mechanical attachment / detachment unit for attaching the display device 1 to the own device. The data holding device 2 may further include a display unit similar to that described above, and the display device 1 may further include a mechanical attachment / detachment unit for attaching the display data holding device 2 to the own device.

  Further, the short-range communication unit 4 on the display device 1 can further receive power for display and display control information in addition to the data to be displayed from the display data holding device 2 side.

  The display element of the present invention includes a partition having a structure for preventing liquid crystals of a plurality of colors injected between two substrates from contacting each other.

  The surface of the partition facing the substrate can have an adhesive force with the substrate, the liquid crystals of a plurality of colors can be cholesteric liquid crystals, or the additive color of the liquid crystals of the plurality of colors can be white.

  In addition, the display device of the present invention has a transmission mode and a reflection mode, displays a first display element whose display contents can be switched, a fixed image or a fixed character, and visually recognizes the display contents through the first display element. A possible reflective second display element.

  The second display element is a printed matter or an object on which a character or image is handwritten, and is attachable to and detachable from the first display element. The second display element is also detachable from the first display element. The display range can be changed according to the position and shape of the upper fixed image or fixed character.

  In addition, the display device of the present invention includes a temperature compensation unit that changes the peak values of two types of driving voltage waveforms corresponding to two stable states of the liquid crystal according to the temperature.

  This liquid crystal is a cholesteric liquid crystal, and the peak value of the drive waveform corresponding to the focal conic state is calculated by averaging the upper and lower limits of the peak value of the drive waveform at the lower limit of the temperature range and the drive waveform at the upper limit of the range. It can also be changed corresponding to a straight line connecting the average value of the upper limit value and the lower limit value of the peak value.

  In addition, the display device of the present invention has a coil installed to receive a high-frequency magnetic field from the outside, a display power supply unit that rectifies a high-frequency voltage induced in the coil and gives a display voltage, and a coil And a logic power supply unit that rectifies the high-frequency voltage induced by the voltage and applies a voltage to a circuit other than the display.

  In this case, the coil has an intermediate tap, one end of the coil is grounded, a resonance capacitor is connected between the intermediate tap and ground, and the logic power supply unit rectifies the voltage at both ends of the resonance capacitor to display power. The part can also rectify the voltage between the other end of the coil and the intermediate tap.

  In addition, the display device is provided with a display unit that receives power from the outside without contact and displays data using the power, and restricts the display function of the display unit according to the amount of power supplied from the outside. A display function control unit is provided.

  In addition, the display device is provided with a power supply for display that uses a part of the electric power supplied from outside without contact and a logic power supply that uses the part to supply power to circuits other than the display part. There is a current control unit that limits the output current of the display power supply in response to a voltage drop of the logic power supply.

  According to the display element driving method of the present invention, in a matrix type display device using cholesteric liquid crystal, a part of the scan electrode is set as a selected reset line, a write line, and a non-selected pause line, respectively. A write data signal is applied to the signal electrode side while shifting the line and the write line.

  In this case, the write AC signal for the reset line and the write line in the selected state can be inverted in the time corresponding to one line and have a period of time corresponding to two lines.

  Next, according to the display element driving method of the present invention, in the matrix display device, a plurality of lines having the same data pattern to be displayed are detected from a plurality of lines on the display screen, and the detected plurality of lines are simultaneously detected. Select and apply the same pattern data to the signal electrode to perform batch writing of the same pattern data. The maximum number of lines to be batch written is inversely proportional to the spatial frequency of the same pattern data. It is also possible to have a relationship of

Furthermore, in the display element driving method of the present invention, the step of converting the image data to be written into the liquid crystal element into n-gradation image data, the step of extracting pixels of each gradation level after the conversion, Sub-image 1 formed by converting tone level 1 (ie, black level) having the lowest luminance and tone level n (ie, white level) having the lowest brightness to black level and white level, respectively. Sub-image 2 formed by converting gradation level 1 having the lowest luminance to gradation level 2 having the second lowest luminance into a black level and combining with gradation level n,... A step of converting a gradation level 1 to a gradation level (n-1) with the lowest luminance to a black level and forming a sub-image (n-1) formed in combination with the gradation level n Of sub-image 1 For the first time from writing, a writing method is used in which sub-images 2,...
A step of converting image data to be written into the liquid crystal element into image data of n gradations, a step of extracting pixels of each gradation level after the conversion, and a gradation having the highest brightness with respect to the extracted pixels; Sub-image 1 formed by converting level 1 and the nth brightest gray level n into a white level and a black level, respectively, 1st brightest gray level 1 to 2nd brightest gray level Sub-image 2 formed by converting up to 2 to the white level and combined with the gradation level n,... The first highest gradation level 1 to the (n−1) th highest gradation level (N-1) is converted into a white level and a sub-image (n-1) formed in combination with the gradation level n is formed. Sub image 2, ... Write method to obtain a display of n gradations written in the order of the probe image (n-1) is used.

  FIG. 6 is a block diagram showing the principle configuration of the display device of the present invention. In the figure, a display device 10 includes a display unit 11 for displaying data, a storage unit 12 for storing information on a method for acquiring data to be displayed, and information on a display format of display data, and storage contents of the storage unit 12. And a control unit 13 for controlling acquisition of display data from the outside and display of display data on the display unit 11. As the display unit 11, it is possible to use a display unit that can display the data semi-permanently or for a certain period of time even when the power is turned off.

  In the display device 10 of FIG. 10, the control unit 13 can automatically start the display device 10 in response to a command given from the outside or the inside. Acquisition of display data from the outside and termination of the display are also possible. Later, the display device 10 can be automatically put into a standby state.

  In addition, the display device 10 displays a data acquisition unit for acquiring display data for which acquisition has not been completed when communication is resumed when communication with the outside is interrupted during acquisition of display data from the outside, and is also displayed on the display unit 11. It is also possible to further include a rewrite prohibiting unit that prohibits rewriting of the data being stored, and a non-volatile storage unit that stores data of one page or more as data that can be displayed by the display unit 11.

  Hereinafter, embodiments of the present invention will be described in several examples. First, as the first embodiment, the information display device, that is, the display side does not have a power source, and display is performed on the display device side using, for example, power transmitted together with data from the wireless terminal side like a non-contact IC card. An information display system will be described.

  FIG. 7 is a configuration block diagram of a first example of such a display system. In the figure, the system is composed of a wireless terminal 20 and a wireless display 21, and the wireless terminal 20 includes an external wireless transmission / reception unit 23 and can exchange external wireless information with the wireless transmission / reception terminal station 22. The external wireless transmission / reception unit 23 may be a wireless LAN transmission / reception unit.

  The wireless terminal 20 includes a power supply unit 25, a control unit 26, an antenna 27 for performing near field communication with the wireless display 21 side, a non-contact transmission / reception unit 28 for controlling communication using the antenna 27, and a wireless display 21 side. A memory unit 29 that stores display data to be sent, a display unit driving circuit 30 that controls data display on the wireless terminal 20 side, a display unit 31, and a speaker 32 are provided.

  The wireless display 21 includes an antenna 36 for near field communication with the wireless terminal 20 side, a transmission / reception unit 37 for performing communication, a control unit 35 for controlling the whole, a display unit, and a memory unit 38 for storing control data. The display unit drive circuit 39 for displaying data, the memory display unit 40, and the mechanical attachment mechanism 41 for enabling the wireless display device 20 to be mechanically attached to and detached from the wireless terminal 20 are provided.

  In general, the wireless terminal 20, for example, a mobile phone, has a small display. In order to enlarge the screen display or display it on a large screen as a whole, a wireless display 21 as a non-power supply display card is used, and a machine as a mechanical attachment / detachment portion for attaching the wireless display 21 to a mobile phone A mounting mechanism 41 is provided to enable integration. At this time, a transmission / reception unit 37 for near field communication is provided near the mechanical mounting mechanism 41, and the near field communication system supplies power for display on the wireless display 21 side simultaneously with display data communication. Have the ability to For example, a short-range wireless communication function such as an IC card or an RF (Radio Frequency) tag can be used.

  As the memory display unit 40, for example, a cholesteric liquid crystal that retains the display state semipermanently even when the power is turned off, for example, a cholesteric liquid crystal described later can be used. It is also possible to use a memory display medium that can be used, or a general buffer memory and its content display section.

  FIG. 8 is a configuration block diagram of a second example of the information display system in the first embodiment. In the figure, the image data sent from the digital camera 43 is displayed on the wireless display 21 side. That is, the image 44 is taken by the image pickup device 45, and the image 44 is displayed on the rear display 46 on the rear surface of the digital camera 43 by the control of the rear display drive circuit 47, and the image 44 is displayed via the antenna 27. Data is sent to the wireless display 21 side.

  9 and 10 are explanatory diagrams of the screen display mode in the system of FIG. In FIG. 9, display data on the display of the wireless terminal 20, that is, the mobile phone, that is, display A is transmitted to the wireless display 21 side, for example, with the display 21 mechanically attached to the mobile phone 20, Even when the wireless display 21 is detached from the mobile phone 20, the display is performed as it is.

  FIG. 10 is an explanatory diagram of a different screen mode in which the display data on the wireless terminal 20 side and the display data on the wireless display 21 side are different. While the display A is performed on the wireless terminal 20 side, the display B is performed on the wireless display 21 side.

  FIG. 11 is an explanatory diagram of the screen selection transmission mode in the system of FIG. First, the screen A to be sent to the wireless display 21 side is selected on the wireless terminal 20 side, and the data of the selected screen A is transmitted to the wireless display 21 side by pressing the transmission button. On the machine 20 side, transmission is possible before the data transmission, display transmission is being performed during transmission, and display end is displayed on the display when transmission is completed.

  FIG. 12 is an explanatory diagram of data display from various terminals including a digital camera on a non-powered display card, that is, a wireless display. In addition to a digital camera, display data of a mobile phone or PDA can be displayed on a non-powered display card. For example, as described with reference to FIG. 7, the mobile phone can display data received from a wireless base station or data acquired via the Internet on a non-powered display card.

  FIG. 13 is an explanatory view of a mechanical attachment mechanism 41 as a mechanical attachment / detachment portion between the wireless terminal 20, for example, a portable terminal and a wireless display, that is, a non-powered display card. In the figure, a leaf spring 50 is fixed on the wireless display 21, and that portion can be inserted into an insertion portion on the portable terminal side and fixed to the wireless display 21. The leaf spring 50 can be fixed to the insertion portion side of the portable terminal, and a mechanical reinforcing plate can be provided on the wireless display 21 side. The joint does not make electrical contact, and there is no problem even if it is slightly damaged by friction or the like. For example, an electromagnetic coil 51 corresponding to the short-range communication antenna 27 described with reference to FIG. 7 can be provided in the vicinity of the attachment portion.

  In FIG. 14, springs 52 and 53 are used instead of the leaf spring 50 of FIG. 13, and mechanical attachment is performed by inserting the wireless indicator 21 between the springs.

  FIG. 15 and FIG. 16 are explanatory views of the mechanical attachment portion on the wireless display 21, that is, the non-power supply display card side. Two mounting portions 54 are provided on the card so that the display card can be mounted vertically or horizontally, and FIG. 15 shows a display state when the card is mounted vertically. Near the two mounting portions, for example, a coil corresponding to the antenna 36 of FIG. 7 is provided, and a driver 55 for displaying and a control IC 56 are provided on the card. FIG. 16 shows a display state when the wireless display 21, that is, the non-powered display card is mounted horizontally.

  FIGS. 17 and 18 are examples of mechanical attachment mechanisms different from those in FIGS. Here, a magnet / magic tape (registered trademark) 57 is used as an attachment mechanism, and FIG. 17 shows a state in which a non-power supply display card is attached to the wireless terminal (portable terminal) 20. FIG. 18 shows a state where the non-power-supply display card is removed from the wireless terminal 20, and a magnet / magic tape 57 is used in place of the mounting portion 54 of FIG.

  FIG. 19 shows an example of a wearable display system in which the wireless display 21 is attached to clothes, for example. Necessary by attaching a Velcro tape 58 to the back side of the wireless indicator 21, that is, the non-powered display card, or attaching the display card itself to the human body in a form that wraps around the arm, and bringing the wireless terminal 20 close to the display card. The screen can be displayed on a display card attached to the human body at any time.

  For example, it is possible to hold a display card on the arm, listen to the sound with the mobile phone close to the ear, and further talk while watching the screen display on the card by bringing the arm close to the mobile phone. In this case, the display is a large screen, and since there is no power supply card, there is an advantage that a battery is not necessary and light and bulky. For example, when the display card is brought close to the chest with the mobile phone in the chest pocket, the display card can be detected, data can be transmitted, and the screen can be displayed.

  Here, regarding the screen display on the wireless display 21, that is, the non-power-supply display card side, it is preferable to display a still image. The reason for this is that, for example, an element that continues to display even when the power is turned off is generally slow in writing speed, but the large screen display itself has a large amount of information, so it is often used as a still image. In addition, it is because a large amount of power is required when the large screen information is handled as a moving image. Furthermore, it is generally desirable to intermittently display the transmission to the non-powered display card in order to reduce power consumption. For example, display power can be greatly reduced by transmitting and displaying data in 50 ms and stopping transmission for 100 seconds.

  The display means of the first aspect of the present invention is the memory display section 40 of FIG. 7, the short-range communication means is the antenna 36 and the transmission / reception section 37, and the display control means is the control section 35 and the display section drive circuit 39. The storage means corresponds to the memory unit 29, and the communication means corresponds to the antenna 27 and the non-contact transmission / reception unit 28.

  The long-distance communication means of claim 2 corresponds to the external wireless transmission / reception unit 23. The mechanical attachment / detachment means in claim 3 corresponds to the mechanical attachment mechanism 41, the display means in claim 4 corresponds to the display section 31, and the mechanical attachment / detachment means corresponds to, for example, the attachment section 50 in FIG.

  As described above, according to the first embodiment, a hands-free large-screen display device that is normally disconnected from a mobile device or the like is integrated with a mobile device such as a mobile terminal or a digital camera when used. The screen of the mobile device can be enlarged to a large screen or a multi-screen for free, and it can be separated after use, and the display result of the large screen remaining displayed can be used using the memory function.

  In particular, by using a cholesteric liquid crystal display element, it is possible to obtain a passive drive type high-definition color memory property display that is low in cost and easy to form into a film. Without using a printer, the same effect as the result of printing with a mobile printer can be realized, and a color display and a large screen which are difficult to realize with a mobile printer can be realized. In particular, in a terminal that is required to be downsized, such as a mobile phone, the substantial effect of large screen display is extremely large.

  In addition, the wireless communication function of the portable terminal can be used to acquire material and catalog information through the Internet and leave it as a large screen display record. If a display with a memory display function is put in a bag or pocket, a large-screen display can be instantly displayed. Further, by attaching the non-power supply display card to the human body, it is possible to eliminate the weight and bulkiness or the trouble of charging, which are the disadvantages of the wearable display using a conventional battery or the like.

  Subsequently, as Example 2 in the embodiment of the present invention, a cholesteric liquid crystal display element as a typical display medium that continues display in a state where the power is turned off, and a display device using the display element will be described.

  First, the properties of cholesteric liquid crystals will be generally described. Cholesteric liquid crystals selectively reflect light in a certain wavelength range, and chiral nematic liquid crystal as one type is a liquid crystal in which a cholesteric phase is formed by adding a chiral substance (chiral material) to nematic liquid crystal. is there. The cholesteric liquid crystal can obtain two stable states, a planar state as a reflective state and a focal conic state as a transmissive state, by electrical control. The planar state and the focal conic state are as long as no external force is applied. It has a memory property that is maintained semipermanently.

  20 and 21 are explanatory diagrams of the planar state and the focal conic state of the cholesteric liquid crystal. In a display device using cholesteric liquid crystal, two states are controlled by switching the alignment state of liquid crystal molecules. FIG. 20 shows a planar state in which light in a specific wavelength region is selectively reflected. In this planar state, the helical pitch of the liquid crystal molecules and the circularly polarized light along the rotational direction of the spiral are selectively reflected. The wavelength λ at which the reflection is maximum is given by the following equation using the average refractive index n of the liquid crystal and the helical pitch p.

λ = n × p
The reflection band Δλ increases as the refractive index anisotropy Δn of the liquid crystal increases.
FIG. 21 shows the focal conic state. In this state, most of the incident light is transmitted and becomes transparent. Therefore, if a layer of an arbitrary color is provided under the liquid crystal layer, the color can be displayed in the focal conic state. Therefore, for example, by setting the wavelength band of the reflected light in the planar state to around 550 nm and providing a light absorption layer (black) under the liquid crystal layer, it is possible to perform a single color display of green on the background color black.

  FIG. 22 is an example of a reflection spectrum of a cholesteric liquid crystal. In combination with a plurality of types of liquid crystal elements (blue, green, red) having different reflection bands, full color display is possible in principle. Further, the reflectance is theoretically close to 50% because of the reflection of either the left or right circularly polarized light.

  23 and 24 are explanatory diagrams of general driving waveforms for the cholesteric liquid crystal. The cholesteric liquid crystal is driven by applying a pulse voltage. When a strong electric field is applied, the helical structure of the liquid crystal molecules is unwound and all molecules become homeotropic according to the direction of the electric field.

  In FIG. 23, for example, by removing the electric field after applying a pulse of ± 40 V, a spiral structure in which the spiral axis of the liquid crystal molecules is perpendicular to the electrode is formed, and the planar state selectively reflects light according to the spiral pitch. It becomes.

  In FIG. 24, for example, when the electric field is removed after applying a pulse of ± 24 V, that is, when the electric field is removed after applying a weak electric field that does not completely unwind the liquid crystal molecules, the helical axis of the liquid crystal is an electrode. A focal conic state is obtained that is parallel to and transmits the incident light. On the other hand, when an electric field having an intermediate strength is applied and then the electric field is removed, a state in which the planar state and the focal conic state are mixed is obtained, and halftone display can be made possible.

  FIG. 25 summarizes the response characteristics of the cholesteric liquid crystal. In the figure, VF0 is a threshold voltage at which the transition to the focal conic state starts, and the voltage range from VF100a to VF100b is a complete focal conic state, VP0 is the threshold voltage at which the transition to the planar state begins, and VP100 is completely This is a threshold voltage that results in a planar state. When the initial state is the planar state, when the pulse voltage is increased, the driving band is set to the focal conic state up to a certain range, and when the pulse voltage is further increased, the driving band is set to the planar state again. When the initial state is the focal conic state, the driving band gradually becomes the planar state as the pulse voltage is increased.

  FIG. 26 shows a configuration example of a reflective liquid crystal display element using cholesteric liquid crystal. In the figure, an ITO (indium tin oxide) electrode 61, a display layer 62, and a light absorption layer 63 are inserted inside a substrate 60, and both ends of the display layer 62, that is, the liquid crystal layer are sealed by a sealing material 64. ing.

  FIG. 27 is an explanatory diagram of an example of segment display using cholesteric liquid crystal. For example, in the last digit “3”, the parts (2) and (5) are in the focal conic state, and the other parts (1), (3), (4), (6) and (7) are planar. Display is performed by driving to the state.

  A configuration of a display element using cholesteric liquid crystal will be described. A cholesteric liquid crystal basically shows a single color display of a certain color tone, and if two liquid crystals are mixed, they are easily mixed and cannot reflect a desired color tone. That is, when two or more liquid crystals are mixed, a neutral color or a non-reflection state is obtained. Therefore, it is necessary to provide partition walls in a pair of opposing matrix substrates so that a plurality of liquid crystals are not mixed in units of adjacent pixels or dots, and each liquid crystal is injected from different injection ports.

  As a method of separating the liquid crystal, a capsule structure in which the liquid crystal is enclosed in a capsule is also used. However, due to the influence of the capsule interface and the capsule thickness, a decrease in contrast due to noise light and an increase in driving voltage are caused. It is not preferable. In addition, it is difficult to arrange a desired capsule in a desired pixel. In the second embodiment, a high contrast and a low cost can be realized by adopting a separation structure using a partition wall.

  FIG. 28 shows a liquid crystal separation structure in a matrix substrate. The present invention can be applied to both a passive simple matrix substrate and an active matrix substrate such as a TFT. In the second embodiment, an example of a separation structure for inserting two liquid crystals is shown as an example of a passive simple matrix substrate. In order to insert two liquid crystals into adjacent dots, a partition wall 62 is formed for each line of the electrode 61 on the lower substrate 60 side. The upper counter substrate 60 has orthogonal electrode lines, and matrix driving is realized. The partition wall 62 is a resin that does not dissolve in the liquid crystal, and can be formed by a photolithography method. The partition wall 62 can be brought into close contact with the counter substrate by reducing the pressure inside the cell. However, it is desirable to improve durability by providing adhesion to the partition wall material and firmly fixing the counter substrate. . The partition wall material is a resin, and can be bonded to the counter substrate by pressure and heat treatment.

  FIG. 29 shows a separation view of the two liquid crystals 63 and 64. Two injection ports are provided so as not to mix each liquid crystal. In general, the liquid crystal is injected by dipping in a liquid crystal reservoir in a vacuum and returning to atmospheric pressure to complete the injection. Therefore, the two inlets must be formed at different ends of the liquid crystal empty cell. As an injection procedure, after injecting one liquid crystal, it is sealed with a sealing material 65, and the other liquid crystal is injected. As shown in the drawing, it is possible to insert different liquid crystals for each adjacent electrode line. By driving a predetermined line, multi-color display and additive color mixture can be displayed.

  FIG. 30 shows a pixel configuration when the two liquid crystals 63 and 64 in FIG. 29 are used. Since display of white and black is desired as the display element, the two liquid crystals have a complementary color relationship so that the additive liquid color becomes white. For example, when orange and blue are used as reflected light of the cholesteric liquid crystal, white is obtained. In FIG. 30, a pixel (pixel) 67 is formed by two dots 66 (sub-pixels) of orange and blue. The reflected light of the cholesteric liquid crystal has an intermediate reflectivity by adjusting the applied voltage, and gradation display is possible, but the stable drive format is binary display (reflectance max and min). In the case of binary display, it is possible to relax the brightness due to the difference in the thickness of the liquid crystal and the accuracy of the driving conditions of the two liquid crystals. The horizontal division corresponding to the segment of the liquid crystal pixel 67 corresponds to a unit of driving by the line of the electrode 61 on the upper substrate 60 side in FIG.

  Therefore, as shown in FIG. 31, the dots are further divided to form sub-dots 68. Gray scale display is possible by driving the sub-dots individually. In FIG. 30, there are four colors of white, black, orange, and blue, but in FIG. 31, nine colors can be displayed.

  30 and 31, it is possible to drive and display the minimum driveable unit of each dot or sub-dot as a virtual pixel unit. If no processing is performed, a high-definition image is formed. However, depending on the image, one color dot is continuous and orange or blue unevenness is formed. Therefore, when displaying an image, a high-definition black and white image is displayed by performing image processing so that the number of two colors to be lit is approximately the same in a certain area, for example, in a range of several mm square. Is possible. For example, when the orange color continues, the vicinity of the orange dot is converted into a blue dot display. With this method, it is possible to convert dots to a high-definition display mode in a monochrome display mode by regarding dots as virtual pixels.

  FIG. 32 shows an embodiment in which three liquid crystals 69, 70, 71 are used. This is an example of insertion of cholesteric liquid crystal exhibiting reflection of three primary colors of R, G and B. Although it was difficult to separate and insert three types of liquid crystal into a single flat substrate, in order to realize the dot arrangement shown in FIG. 32, one liquid crystal (Y) 70 If the line structure is a dot array having a period of X, Y, Z, Z, Y, and X that are alternately injected between the liquid crystals (Z) 69 and (X) 71, three types of liquid crystals can be formed on one plane. It has been found that it can be inserted into the substrate. Two types of dot arrangement, one pixel for RGB and one pixel for BGR, are alternately arranged. The G color has high resolution of human perception, and only G color dots are arranged at equal intervals. The R color and the B color have low perceptual resolving power, so there are few problems even if they are not arranged at equal intervals. The inlets are each arranged on different ends to prevent mixing.

  33 and 34 show an example in which dots are further divided to form sub-dots 68 to realize high resolution and gradation display. Assuming that binary display is performed as in FIG. 30, 8-color display is possible in FIG. 33 and 64-color display is possible in FIG. In FIGS. 33 and 34, if the minimum driveable unit of each dot or sub-dot is driven and displayed as a virtual pixel unit, a high-definition image is formed as in FIGS. It is also possible to convert to a high-definition display mode for black and white images by image processing.

  Next, a display device in which a display element using cholesteric liquid crystal and a print medium using paper or photographs are combined will be described. As described above, the cholesteric liquid crystal has two stable states, a planar state as a selective reflection state and a focal conic state in a substantially transparent state. In general, a light absorption layer (black layer) is provided under a liquid crystal element, and light in a reflective state and dark in a transmissive state are displayed.

  However, in the cholesteric liquid crystal, if the light absorption layer is not provided, the background of the liquid crystal element can be visually recognized in the transparent state, that is, the focal conic state. Therefore, a liquid crystal display device with a wide range of application can be provided by utilizing the transparent state in the focal conic state and fusing with a print medium, generally a paper medium.

  For example, a menu display of a restaurant has been proposed as an application example of electronic paper capable of semi-permanent display, but it is not necessary to change the display for the entire area of the menu. For example, a product image may generally be a fixed display, but it is desirable to use a photograph in order to improve the image quality. It is desirable to use a variable display for the price to be displayed together and the special sale for today. Therefore, in the second embodiment, a photograph or the like as a print medium and an electronic paper medium, for example, a display element using cholesteric liquid crystal are overlaid to realize a display form that is overlaid as a whole. Product images are highly realistic as printed matter, and the contents of price and special price information can be easily changed using electronic paper, and fusion of paper and electronic paper can be achieved.

  For example, by using an electronic paper that uses cholesteric liquid crystal as a matrix display type, it is possible to realize an appropriate display according to the display content on the printed matter. Many forms of application can be considered by making a printed material into a template. For example, by using a calendar as a printed material, a variable schedule book is realized using a display of electronic paper superimposed on the calendar.

  FIG. 35 shows a superimposed display example of a variable display element using a fixedly displayed printed matter (photograph) and a cholesteric liquid crystal. The variable display element 75 is overlaid on the surface of the printed material 74. This variable display element does not have a light absorption layer. FIG. 36 shows a display state. In the display element 75 on the printed material 74, a transmission mode (focal conic state) (left) and a reflection mode (planar state) (right) are shown. When incident light 77, which is illumination light, is applied to the display element, in the transmissive mode (left), the printed matter is illuminated as it is, reflected light 78 corresponding to the image of the printed matter is reflected, and passes through the transmissive mode display element. It is visible as it is. That is, the printed matter is visually recognized as it is. In the reflection mode (right), light having a wavelength corresponding to the layer pitch of the cholesteric liquid crystal is reflected, and other light is transmitted through the liquid crystal and irradiated on the printed matter. Reflected light corresponding to the image of the printed material is reflected and transmitted through the liquid crystal in the reflection mode. Therefore, the reflected light 79 of the liquid crystal and the reflected light 78 of the printed material are superimposed on each other to form the display light 80. Integration of printed materials of paper media with good image quality and display elements of variable display media is planned.

  The liquid crystal exhibits a color corresponding to the layer pitch. Therefore, it may be difficult to visually recognize depending on the color of the printed material in the lower layer, and it is necessary to consider the region of the printed material on which variable display is performed. In order to increase the contrast and increase the visibility, this region of the printed material is preferably black. Alternatively, the visibility can be improved by reducing the reflectance such as gray. Further, by coloring this region and setting the reflected light 78 to a specific color, it becomes an additive color mixture with the display element reflected light 79, and the color can be changed. For example, the display color is set to white by setting the reflected light 79 of the display element to orange and the printed material to be blue. It is also possible to give a color change for each region by various ideas of the printed matter. White is the most desired display color. A white display can be realized by setting the color of the printed material and the color of the reflected light of the display element to a complementary color relationship. Orange and blue are complementary colors.

  FIG. 37 shows an example for the purpose of selling products such as menus or catalogs. As the product image, a printed material having excellent display quality is used. For example, in a restaurant, an image that looks delicious is printed and fixed. Other display, mainly character display, is performed by a variable display element. The portion of the printed matter in the lower layer portion of the variable display element 75 has a printed pattern such as black that improves visibility. As the character display, various displays such as price, special sale, lunch menu designation, business hours guidance, and advertisement can be assumed. Various applications can be considered by changing the display of the variable display element online. For example, custom menus tailored to customers, such as pricing according to time of day, adjustment of inventory quantity, change of specials, advertisement display tailored to customers, group discount, female discount, family discount display, member discount, point discount, etc. Can be provided on the spot. It can also be enlarged on the spot for the elderly. As the product image, an image with good reality is displayed.

  The example shown in FIG. 38 is an example of the restaurant menu. A variable display area is set below the image to display the price. FIG. 38 is an exploded view of the printing unit and the variable display unit. When changing the image, for example, by replacing the product, only the printed material needs to be replaced. The printed material is easily removable. Since the variable display element is a matrix type display element, it can easily cope with a layout change of printed matter.

  FIG. 39 shows an example in which the printed matter shown in FIGS. 37 and 38 is replaced with a schedule table. The printed material is a calendar. The schedule is entered on the variable display element online. If you are online, you can enter schedule changes at any time, and you can also see the schedule of multiple people. Even if there is a schedule change, it can be reflected immediately. Sharing is also possible, enabling information sharing and effective management. When the moon changes, the printed material is removed and replaced to create a new schedule. Moreover, if it is desired to write by hand, it can be attached and detached and handwritten on the printed matter. Since the variable display element is a matrix display element as in FIGS. 35 to 38, the layout can be easily changed according to the printed matter. A pattern is printed on the printed matter in consideration of the display area. The schedule display unit has a pattern that is easy to visually recognize, such as black, gray, or a complementary color.

  FIG. 40 shows an application example used for map display. The structure is the same as FIG. The printed material is a layout diagram such as a road map, a venue guide map, and a building plan view, and the variable display unit can display a current position, a destination instruction, a passage history, and the like. It is also possible to display advertisements tailored to the destination. You can also display the scheduled transit time, which is only possible online. When the destination is significantly changed, the printed material is detached and a new printed material map is set. If this display device is used, it becomes a very convenient guide plate. FIG. 40 shows an example of venue guidance for events and the like. The printed matter can be changed and distributed according to the customer. If a wireless display system is installed, it is possible to display the current position every time it passes through each gate. It is also possible to display useful information near the current location.

  FIG. 41 is an example corresponding to reference books and problem collections. The problem is printed on the printed matter, and the answer and explanation are displayed later. It is easy to understand because you can read answers and explanations on the spot. When changing the problem, the printed matter can be removed and replaced. FIG. 41 is an example of a problem collection. Unlike a monitor display on a personal computer, it is a reflective display device that can be understood efficiently with little fatigue even after long hours of study.

  FIG. 42 is an example corresponding to a display for simulation used in a financial institution such as a bank or insurance. The common items are printed on the printed matter, and the customer's custom numerical values are displayed online. Since the simulation result is obtained on the spot, it can be explained in an easy-to-understand manner. When changing the product, the printed material may be detached and replaced. FIG. 42 shows an example of a bank loan simulation. If you are a life insurance accountant, you might go to a customer with a laptop. There are times when the display on the personal computer is explained to the customer, but it is very difficult to see and it is difficult to convince the customer. If the display device of Example 2 is used, the visibility is good and the customer can easily understand the explanation.

  As described above, according to the second embodiment, multi-coloring can be realized by injecting liquid crystals of a plurality of colors in a matrix display element using cholesteric liquid crystals. Cost reduction is realized by using a simplified member having fewer interfaces, higher contrast, and a laminated structure.

  In addition, by combining a cholesteric liquid crystal matrix display element with a variable display element and combining it with printed matter as a fixed display element, it is possible to fuse electronic paper and paper, and to maximize the characteristics of electronic paper and paper. It becomes. It is possible to develop various application forms simply by making a printed material as a template, detaching it from the variable display element, and changing the contents of the template. By making a template of a printed material into a database, it is possible to immediately change the layout, contents, and update of the display element. The variable display element can be used many times and the cost is reduced. The fixed display element may be handwritten instead of the printed matter, or a cholesteric display element may be superimposed on a picture drawn on the wall of the building for superimposing display.

  Next, Example 3 will be described. In the present embodiment, for example, when a non-power supply display card as in the first embodiment is used to realize semi-permanent data display, the amount of power supplied from, for example, a non-contact IC card reader / writer is small. Therefore, it is necessary to use various control methods for the power supply circuit. Such control of the power supply circuit will be described as a third embodiment.

  As described with reference to FIGS. 23 and 24, driving of the cholesteric liquid crystal requires two kinds of voltage values corresponding to the planar state and the focal conic state, respectively. Moreover, the planar drive voltage is about 40 V, which is considerably higher than other display elements. For example, when a general DC-DC converter is used, a capacitor having a large capacitance of μF order is required, and it is extremely difficult to make the power supply circuit within a thickness of about 1 mm, that is, within the thickness of the non-power supply display card. Have difficulty.

  Therefore, in the third embodiment, a high-frequency magnetic field used for signal and power supply is used in a non-contact IC card or an RF tag without using a DC-DC converter, and an ultra-thin circuit has a high voltage of about 40V. Use a power supply circuit that generates voltage.

  FIG. 43 shows an example of such a power supply circuit. This power supply circuit serves as a power source for display, for example, a logic for a liquid crystal driver, and a power source for display for an element itself, that is, a cholesteric liquid crystal.

  In FIG. 43, for example, an intermediate tap T is provided in a coil having an inductance L in which a voltage is induced by a high-frequency magnetic field from the non-contact IC card side, one end of the coil is grounded, and resonance occurs between the intermediate tap T and the ground. A capacitor C1 is connected, a logic voltage is supplied via a half-wave rectifier circuit, and a resonance capacitor is not connected between the other end of the coil and the intermediate tap T. A display voltage is supplied. Thus, by connecting the resonance capacitor only between the intermediate tap for taking out the voltage for logic and the ground, the influence of manufacturing variations can be reduced, and stable DC power can be supplied.

  In FIG. 44, instead of providing an intermediate tap in FIG. 43, a logic power source and a display power source are independently provided. The upper circuit in the figure is a power supply circuit for logic, and it can be considered that the lower part of FIG. 43 is made independent. The value of L1 for receiving power supply in a general non-contact IC card is, for example, about 1.4 μH, and by using, for example, 100 pF as C1, 5 V can be obtained as a logic voltage. If a DC-DC converter is used, this voltage can be boosted to obtain a display power supply voltage. For this purpose, a capacitor on the order of μF is required as described above. Therefore, for example, the display power supply voltage is obtained by setting L2 = about 4 to 5 μH.

  Next, for example, in a passive matrix driving circuit, it is necessary to apply a voltage corresponding to planar and focal conic driving to a liquid crystal cell on a scanning line at a selected level, and to a liquid crystal cell on a scanning line at a non-selection level. Therefore, it is necessary to apply a voltage that does not change the written state at the time of selection regardless of the level of the segment line. That is, it is generally necessary to apply a voltage that suppresses crosstalk. For example, a commercially available STN liquid crystal driver LSI requires five voltage values.

  FIG. 45 shows a configuration example of a power supply circuit corresponding to such a case. The power supply circuit for logic is the same as that in FIG. 44. However, as a power supply circuit for display, a power supply circuit using voltage doubler rectification is connected in series in multiple stages instead of the power supply circuit shown in the lower part of FIG. Circuit is used. In this multistage connection circuit, for example, five kinds of voltages can be supplied by extracting voltages at appropriate locations according to the required voltage values. As this rectifier circuit, a half-wave rectifier circuit or a full-wave rectifier circuit can also be used. When it is necessary to prevent overvoltage in the circuits of FIGS. 43 to 45, the reliability of the power supply can be improved by inserting a Zener diode between the voltage output terminal and the ground in parallel. In FIG. 45, among the four coils on the display power source side, L2 and L4 are wound in the same direction, whereas L3 and L5 are wound in the opposite direction. As a result of experiments, it was found that high voltage can be generated by using coils with different winding methods.

  Next, for example, when a non-contact IC card is used as a non-power-supply display card, the amount of power supplied from the non-contact IC card reader / writer increases depending on the reader / writer model, the distance between the reader / writer and the card, and the like. Change. For this reason, when the display unit on the card is always operated, the communication distance is remarkably shortened compared with a normal non-contact IC card having no display unit, or the operation becomes unstable due to power shortage during communication. there is a possibility. Therefore, in the third embodiment, the display function is limited according to the amount of power supply corresponding to such a case.

  FIG. 46 is a configuration example of a circuit that completely cuts off the power supply to the display unit according to the value of the display power supply input voltage corresponding to the power supply amount from the reader / writer side, for example. In the figure, the voltage from VR1 obtained by dividing the display power supply input voltage is compared with the reference voltage by the comparator (CMP1), and when the display power supply input voltage is high, the output of CMP1 becomes high level (H). . The circuit constituted by TR1, TR2 and R1 is a general current limiting circuit. When the output of CMP1 is H, a power supply output for display is supplied, but when the output of CMP1 is low level (L) In this case, the power supply for display is totally cut off. By appropriately setting the reference voltage, the power supply amount, that is, the power supply input voltage for display operates the non-contact IC card chip, but if this value is close to the required value, use this circuit. The power supply to the display unit is completely cut off.

  FIG. 47 is a configuration example of a clock output circuit for extending the drive period of the display unit on average in accordance with, for example, the amount of power supplied to the non-contact IC card. This circuit has a power supply amount that is sufficiently larger than the minimum value required for a non-contact IC card chip, that is, a necessary value for operation, but smaller than an average necessary amount during operation of the display unit in a steady state. In this circuit, the clock cycle is extended on the average according to the amount of power supplied, and the drive cycle of the display unit is delayed.

  In FIG. 47, when the display power supply voltage divided by VR2 is small, the output of CMP2 becomes L and the clock output as the output of gate AND1 stops. For example, in the display power supply circuit described with reference to FIG. 44, when the clock is stopped and the power supply is cut off, the capacitor C3 is charged, and the display power supply voltage is recovered, whereby the clock is output again. By repeating such an operation, the clock cycle, that is, the drive cycle of the display unit is delayed on average.

  FIG. 48 is a configuration example of an output circuit of an image display prohibition signal for displaying only character data on the display unit and not displaying image data in accordance with the power supply amount. This circuit displays only character data on the display unit when the power supply is larger than the required value of the non-contact IC card chip, but much smaller than the average required value when the display unit is operating in a steady state. This circuit limits the display function by not displaying data. In the figure, when the display power supply voltage divided by VR3 is smaller than the reference voltage, the output of CMP3 becomes H and an image display prohibition signal is output.

  Next, the current limitation of the display power supply will be described. A passive matrix type cholesteric liquid crystal display panel can be driven by an existing passive matrix type STN liquid crystal driver LSI by using a power supply circuit as described above. Except at the time of start-up, power consumption is relatively small, and it is possible to operate sufficiently with power supplied from a weak output non-contact IC card reader / writer or the like. However, since such an existing driver LSI is premised on moving image display, the conduction impedance of the transistor at the final stage is low, and a very large instantaneous current (5 to 10 times that in steady operation) is generated in a transient state at startup. Flowing. For this reason, there is a possibility that the existing driver LSI cannot be started even if power several times that in steady operation is supplied.

  However, it is extremely disadvantageous in terms of cost to prepare a power supply having a large supply capacity only for startup. Further, existing weak output non-contact IC card reader / writer or the like cannot supply power 5 to 10 times that in steady operation. For this reason, in the third embodiment, the current of the power supply for display is limited in order to stably start the existing driver LSI with the supply power as close to the power consumption during the steady operation as possible.

  FIG. 49 is a configuration example of a current limiting circuit of a display power supply. In the figure, by setting the value of VR1 in advance so that the current is limited when the voltage of the logic power supply becomes a predetermined value or less, for example, the value of the voltage drop of the logic power supply is reduced to 5% of the standard value. If it exceeds, current limitation for the power supply for display is performed.

  At the time of start-up, since the display power supply voltage generally increases monotonically with time, the clock output is stopped until the voltage value of the display power supply exceeds a predetermined value using the same circuit as in FIG. The existing driver LSI can be started stably and quickly. In this case, unlike the description with respect to FIG. 47, the display power supply voltage only increases monotonously, so that the clock is stopped until the value exceeds a predetermined value, for example, 95% of the standard value.

  In an existing general liquid crystal driver LSI, the display power supply current may greatly exceed the average current during steady operation depending on the display pattern even when it is not activated. At this time, the current driver is limited in the same manner as at the time of startup, and the driving of the display panel is interrupted until the display power supply voltage recovers to a predetermined value, whereby the existing driver LSI can be stably operated.

  Next, temperature compensation in the driving characteristics of the cholesteric liquid crystal in Example 3 will be described. For the cholesteric liquid crystal, two types of driving waveforms having different peak values corresponding to the planar and focal conic states are required. In addition, the peak value varies with temperature. For this reason, in order to widen the operating temperature range, temperature compensation is required to change the peak value according to the temperature. In the third embodiment, a peak value margin in a wide operating temperature range is secured by linearly changing the peak value of the drive waveform according to the temperature.

  FIG. 50 shows examples of peak values in the planar and focal conic driving waveforms of the cholesteric liquid crystal when the pulse width is 10 ms. Since a planar state is always obtained above a certain peak value, the peak value corresponding to the planar state is represented by a single curve corresponding to the lower limit value. On the other hand, since the change to the focal conic state is performed only in a voltage range of a certain peak value, the peak value corresponding to the focal conic drive is represented by two curves corresponding to the lower limit value and the upper limit value. The

  In FIG. 50, the peak value corresponding to the focal conic state varies greatly depending on the temperature. Therefore, the margin of the peak value for driving to the focal conic state becomes small regardless of the temperature.

  On the other hand, it is known that if the pulse width is widened, the peak value margin corresponding to the focal conic drive becomes large. FIG. 51 shows an example of a peak value corresponding to the planar and focal conic driving with a pulse width of 50 ms. The peak value margin is several times that in the case of the pulse width of 10 ms in FIG. 50, but the display speed is reduced to 1/5.

  FIG. 52 shows an example in which the crest values of two types of drive waveforms in the planar drive and the focal conic drive in Embodiment 3 are linearly changed within the operation range according to the temperature. Compared with FIG. 50, three lines are shown between the upper limit and the lower limit of the focal conic state. The central line is a lower limit value of the operating temperature range, that is, a wave corresponding to the focal conic state at 0 ° C. It is a straight line connecting the average of the upper limit value and the lower limit value of the high value and the upper limit of the operating temperature range, that is, the average of the upper limit value and the lower limit value of the crest value at 50 ° C.

  In the third embodiment, the peak value of the driving waveform corresponding to the focal conic state is basically changed by this central straight line corresponding to the temperature, but the margin is originally in FIG. 50 at each temperature. It suffices to enter between the upper limit value and the lower limit value corresponding to the focal conic state, and the new margin becomes larger than the margin in FIG. That is, among the above-mentioned three straight lines corresponding to the focal conic state, the upper straight line indicates the maximum value of the peak value within the margin, and the lower straight line indicates the minimum value of the peak value within the margin. The value in the margin corresponding to these three straight lines is 0 ° C., the minimum is 25.4V, the maximum is 32.6V, and the average is 29.0V. At 50 ° C., the minimum is 15.9 V, the maximum is 23.7 V, and the average is 19.8 V.

  In FIG. 52, the peak value of the drive waveform in the planar state in the third embodiment is, for example, a value obtained by adding a predetermined value to the peak value of the drive waveform corresponding to the focal conic state at the same temperature, or multiplying by a predetermined value. It can be changed corresponding to the temperature. The characteristic is shown in FIG. 52 by the line above the planar state. The value at 0 ° C. of this line is 49.3V, which is 1.7 times the average value of 29.0V among the three lines corresponding to the focal conic state. Moreover, the value in 50 degreeC is 33.66V, and is 1.7 times the average value 19.8V corresponding to a focal conic state.

  FIG. 53 is a configuration example of a temperature compensation circuit for voltage peak values of the planar drive and focal conic drive described in FIG. In the drawing, the amplification factor of AMP1, that is, the amplifier to which the temperature sensor output is given is equal to R2 / R1, and its value is 1.7.

  The sensor output at a certain temperature is calculated by an arithmetic circuit (not shown), and the output values at 0 ° C. and 50 ° C. are the values of the lines indicating the average value among the three lines corresponding to the focal conic drive described in FIG. It is set to be equal. That is, the sensor output value is 29.0 V at 0 ° C. and 19.8 V at 50 ° C. Therefore, the AMP1 output is 49.3 V at 0 ° C. and 33.66 V at 50 ° C. These values are equal to the values of the temperature compensation characteristic line for the planar state described in FIG.

  TR1 and TR2 constitute an emitter follower circuit for sufficiently reducing the output impedance, and the output values of the respective emitter voltages, that is, the planar voltage and the focal conic voltage, are approximately 0.7 V lower than the base voltages of the respective transistors. . Therefore, the planar voltage output value is about 48.6 V (= 49.3-0.7) at 0 ° C. and about 33.0 V (= 33.66-0.7) at 50 ° C., and these are in the planar state. The minimum value of the peak value of the corresponding drive voltage waveform, that is, the minimum voltage corresponding to the planar state described with reference to FIG. 50, is sufficiently higher than 43.3 V at 0 ° C. and 30.9 V at 50 ° C.

The base voltage of TR2 is a value obtained by dividing R4 times the output voltage of AMP1 by (R3 + R4). The value of this coefficient is equal to 1 / 1.7, and the output voltage of the TR2 emitter voltage, that is, the focal conic voltage, is 28.3 V (= 29.0-0.7) at 0 ° C., and about 19 at 50 ° C. It is 1V (= 19.8-0.7). These values are represented by the three straight lines described in FIG. 52, and are sufficiently larger than the minimum voltage (25.4V and 15.9V) corresponding to the focal conic state and the maximum voltage (32.6V and 23.23). 7V) is sufficiently smaller.
Further, as described above, the peak value of the drive waveform corresponding to the focal conic state is linearly changed in this manner in accordance with the operating temperature of the liquid crystal cell, so that the pulse width is 10 ms or the pulse width is 50 ms. Equivalent margin can be secured. That is, even though the display speed is increased by a factor of 5, an equivalent value can be secured as a peak value margin, and a display device using cholesteric liquid crystal can operate stably over a wide temperature range.

  In the above, as a third embodiment, for example, a power supply circuit for a non-contact IC card, a display function limiting circuit, a display power supply current limiting circuit, a temperature compensation circuit for a cholesteric liquid crystal driving voltage, and the like have been described. Some will be used in combination rather than each independently. About the combination, it is possible to select some circuits as needed and combine them.

  In addition, the value of the element in each circuit and the value of the reference voltage can be determined relatively easily. For the temperature compensation circuit of FIG. 53, the determination of the resistance value and the like have been described in detail. For example, the operation of the current limiting circuit described in FIG. 49 is described in a general handbook and the like. The value can be easily determined.

  As described above, according to the third embodiment, for example, the power supply circuit for a display panel using cholesteric liquid crystal can be significantly reduced in cost and thinned, and the display function is limited in accordance with the amount of power supplied. As a result, the range of mobile device applications can be reduced because the communication distance can be shortened and operation instability can be avoided, and the current of the display power supply at startup can be limited to start up the existing driver LSI stably and quickly. It is greatly expanded.

  Next, a driving method of a liquid crystal element in a display device using a semi-permanent memory display element, for example, a cholesteric liquid crystal, an image display method, and the like will be described as a fourth embodiment. In the fourth embodiment, for example, in order to use a display device using a cholesteric liquid crystal element without a power source, a driving method and an image display method for driving the liquid crystal element and displaying an image in a form that consumes as little power as possible are described. To do.

  FIG. 54 is a block diagram showing a configuration of a driver for driving a liquid crystal display element according to the fourth embodiment, for example, a matrix type liquid crystal element. This driver itself has substantially the same configuration as, for example, an existing STN common driver that is commercially available. This is not a configuration unique to the present invention, and the fourth embodiment is characterized by its driving method.

  In FIG. 54, power and data transmitted from the wireless terminal 20 that transmits power and data, or an IC card reader / writer, etc. are received by the power / data receiving unit 81, and the signal control circuit 82 corresponds to the reception result. Thus, the signal conversion circuit 83 is controlled, and the matrix type liquid crystal element 84 is driven and displayed.

  The matrix type liquid crystal element 84 generally includes a scan electrode for selecting a line and a signal electrode for giving data, and polarity inversion for making the drive signal of the liquid crystal element an alternating current is provided on the scan electrode side. A signal FR, an Eio signal as a line selection signal, an Lp signal for shifting a scanning line together with data latch on the signal electrode side, and the like are given. In addition to the FR signal and the Lp signal, a data signal used for writing is supplied to the signal electrode side.

  In general, an Eio signal for selecting a scan electrode for writing data line by line from the top line is given to the scan electrode side, and this mode is referred to as a common mode here. On the other hand, instead of writing line by line from the top, it is also possible to give a signal called a segment mode for selecting a line to write data to an arbitrary line. A switching signal for switching is also provided.

  FIG. 55 is an explanatory diagram of a screen rewriting method according to the fourth embodiment. Conventionally, a method in which the previous display screen is collectively reset at the time of screen rewriting is generally used. However, in this method, at least several tens of mW of power is consumed at the time of resetting. It is much larger than 5 to 10 mW of electric power supplied from the display device, and it is difficult to perform a batch reset on the display device side having no power source.

  Therefore, in the fourth embodiment, the power consumption is reduced by resetting the screen by repeating the operation of resetting several lines, for example, four lines, and simultaneously writing data for one line by the number of lines. As the data for use, for example, the write data itself is used for resetting without using special reset data for making all pixels white.

  In FIG. 55, the lower half of the screen shows a previous display screen, and the upper half shows a new display screen. Here, the writing start line starting from the top line, that is, the above-mentioned writing line for each one line is almost in the vicinity of the center of the screen, and the data on this line is written and the reset line, for example 4 The line is reset using the write data. This operation will be further described with reference to FIG.

  In FIG. 56, first, an operation for setting four lines as reset lines is performed. If the Eio signal and the Lp signal are simultaneously input in the same figure, the first line on the screen in FIG. 55 is first selected, and data can be written to that line. Next, when the second pulses of Eio and Lp signals are input together, the first selected first line is shifted by the Lp signal, the second line is selected, and the Eio signal input simultaneously As a result, the first line is selected at the same time, and the first and second lines are selected. This operation is repeated, and the first to fourth lines are selected in the reset line setting section, and data can be written to the four lines.

  In the next pause line setting section, only the Lp signal is input, and by this pulse, one line is shifted, and the second to fifth lines on the screen are selected.

  At the beginning of the next writing period, the Eio signal and the Lp signal are input simultaneously, and the previously selected second to fifth lines are shifted by one line, and the third to sixth lines are selected. The first line on the screen, that is, the first line is also selected by the input of the Eio signal. By giving the first line data in this state, the data to be originally written is written to the first line, and the first line data is used as the reset data from the third line to the sixth line. Given, the last displayed data is reset. At this time, the second line is a pause line set in the pause line setting section, and no data is written.

  Corresponding to the input of the next Lp pulse, the previously selected line is shifted, and the second and fourth to seventh lines are selected. In this state, the data for the second line is given, the data originally written to the second line is written, and the previous display data from the fourth line to the seventh line is reset.

  Further, by the input of the next Lp pulse, the third line and the fifth line to the eighth line are selected in the same manner, and the data of the third line is written. In the third line, the data of the first line is written when the second previous Lp pulse is input. Generally, the response time of the cholesteric liquid crystal is on the order of several tens of ms, although it depends on the physical properties of the material. At the time of input of the Lp pulse as the timing at which data of the second line is written, the third line is a pause period, and in this period (for example, 50 ms or less), the pixels of the second line are in the focal conic state or the planar state. It is a transitional state in the middle of the transition to, and when the data on the third line is actually given, either the focal conic state or the planar state as the actual writing state is determined. Become. Such an operation is repeated, for example, up to the 240th line, that is, until the data of the lowermost line on the screen is written.

  Next, different power consumption suppression methods in the fourth embodiment will be described with reference to FIG. FIG. 57 shows a signal for determining the polarity inversion in the drive waveform of the liquid crystal element described in FIG. 54. In general, in the cholesteric liquid crystal, it is desirable to invert the polarity of the pulse in one line of data write pulse. This is to solve the problem of deterioration of liquid crystal and image quality (afterimage, crosstalk, etc.). For example, there is a method of inverting the polarity every few lines or every frame, but the fluctuation of ions in the liquid crystal, etc. Causes afterimages and display noise, and is not a preferable method.

  The upper side of FIG. 57 shows the conventional polarity inversion method of the drive signal, and for each line, a method was used in which polarity inversion was performed by first applying a positive pulse and then a negative pulse. . The waveform on the lower side of FIG. 57 is the polarity inversion method in the fourth embodiment. For example, the polarity of the drive signal is reversed in such a way that a positive pulse is first applied to the first line, then a negative pulse, and then a negative pulse is first applied to the second line, and then a positive pulse is applied. By doing so, the polarity in one line is inverted, but the inversion period itself is doubled, so that power consumption can be suppressed and there is no problem in display quality.

  58 to 60 are explanatory diagrams of the effect of the driving method described in FIGS. 55 to 57. FIG. 58 and 59 show the effects of the fourth embodiment corresponding to FIGS. 3 and 4 described as the prior art. By using the driving method as described above, instead of using a long pulse having a period of several tens of ms, even if a short pulse having a period of, for example, about 8 ms is used, no decrease in contrast occurs, and the weakness of about 5 mW. High-quality data can be written on a QVGA size screen (horizontal 320 dots × vertical 240 dots) by a driving circuit using a large amount of power.

  FIG. 60 is an explanatory diagram of the power consumption suppression effect obtained by resetting several lines, or four lines in FIG. 56, without performing batch reset in the fourth embodiment. When batch reset is performed, power consumption at the start of driving becomes extremely large, but in the fourth embodiment, such increase in power consumption can be suppressed.

  Next, a skip driving method as an image writing method in the fourth embodiment will be described with reference to FIGS. 61 and 62. FIG. In this drive method, that is, the skip drive method, data can be written to a pixel at an arbitrary position on the matrix by applying a segment mode signal to the scan electrode side instead of the common mode described above. To do.

  In FIG. 61, the entire display screen is first reset. In this reset, the entire state may be shifted to the focal conic state at the same time. However, since power consumption increases, a simple reset to an incomplete focal conic state by a short pulse with a period of 3 ms or less has an effect of resetting. Alternatively, the entire display unit may be divided into a plurality of blocks and reset for each block.

  Next, a portion where the same pattern, here, a white pattern is to be written is selected on the scanning electrode side, and batch writing is performed on the electrode of that portion. As a result, a solid white pattern can be drawn on a plurality of lines at the same time, and the driving time can be shortened.

  Here, a solid pattern is used as the same pattern. However, the same pattern is not particularly limited. However, a pattern with a high spatial frequency such as a checkered pattern consumes more power, and batch writing is performed according to the pattern. It is necessary to limit the number of lines. That is, the number of lines to be selected at a time is reduced as the pattern has a higher spatial frequency.

  In the case of a random pattern image processed by the error diffusion method that diffuses the error for a pixel to surrounding pixels in image processing, the probability that the same pattern exists will be low, but adding noise to the density signal of the gradation image The same pattern may exist in a systematic dither method as a kind of binary dither method that binarizes by threshold processing or a halftone image by halftone dots. However, this skip driving method is particularly effective when there are many white areas such as text display.

  In FIG. 61, after sequential writing of the same pattern, normal sequential line driving (passive driving) is performed, and the remaining portions other than the same pattern are sequentially written. At this time, if the interlace scanning is used, the entire image can be recognized quickly. This skip drive can be realized with a simple drive circuit without using a complicated method like MLA drive, and is characterized in that the number of lines to be collectively driven is different depending on the pattern.

  FIG. 62 is a process flowchart of this skip drive method. In the drawing, the left side is a flowchart of the same pattern detection process as the pre-drive process. In this process, binary screening by an error diffusion method or the like is performed in step S1 using, for example, an 8-bit original image, a scan electrode as a data comparison source is selected as loop 1 in step S2, and data is determined in step S3. The scan electrode as the comparison destination is selected, the pattern comparison of the data for each electrode is performed in step S4, and it is determined whether or not the same pattern is detected in step S5. After the coordinates or addresses where the same pattern exists are stored in the address storage memory 86 of the same pattern, or if they are not detected, the comparison scan electrode is immediately changed in step S3, and the processing is continued. When the comparison with respect to the data of the scan electrode as the comparison source selected in is completed, Processing the scanning electrodes is changed as a comparative source in step S2 is continued, the comparison of all data has finished processing after being made.

  The flowchart on the right side of FIG. 62 is a flowchart of driving, that is, a writing process. When the processing is started in the figure, for example, batch reset processing of the entire display unit is performed in step S10, one identical pattern is taken out from the address storage memory 86 of the same pattern in step S11, and the pattern is retrieved in step S12. A plurality of scan electrodes to be written are selected at the same time, data is written in a batch in step S13, and the processes in steps S11 to S13 are performed for the next pattern. When the writing of the same pattern is completed, a writing loop for the unwritten line is executed in step S14, and passive writing of data is performed line by line on the remaining portions other than the same pattern written in step S15. Processing is complete.

  Next, the multilevel writing method in the fourth embodiment will be described with reference to FIGS. 63 and 64. FIG. In general, a display device using a cholesteric liquid crystal has a problem that the entire image becomes thin because the transition to the focal conic state becomes insufficient when writing is performed at high speed. It is possible to execute multi-value writing in which tone writing is performed and repeated to display a clear image.

  First, the case of ternary writing will be described. When the original image is ternary, for example, 8-bit 256 gradation, screening processing is performed at three levels of 0, 128, and 255. The type of this process need not be particularly limited, but a pseudo halftone image with high resolution can be generated by using the above-described error diffusion method or the blue noise mask method as image processing over a larger area. Can do.

  After the ternary screening process, a black (0) level pixel is extracted, and only the extracted pixel, that is, a pixel to which black is originally written, is extracted, and only a halftone image of the halftone image is scanned as the first scan. Write. That is, by driving the liquid crystal element at a higher speed than usual, an image of an intermediate gradation level is written with the output voltage from the driver fixed. By adjusting the driving speed, an image in which halftone data is written to a pixel where black should be originally written as shown in FIG. 63 is obtained.

  Thereafter, as shown in FIG. 64, by performing the second scan, that is, by writing data in which the black (0) level and the intermediate (128) level are converted to the black (0) level, the intermediate gradation in FIG. The pixel becomes a black gradation, and intermediate gradation or white gradation data is written in the other portions, and a ternary image is finally formed. As a result, a multi-value gradation image can be easily displayed, and the user can quickly grasp the entire display image. That is, initially, a blurred image is displayed gradually and clearly, and multi-value display of three or more values can also be realized by performing writing more times with an appropriate scanning speed. In contrast to this method, a method of cumulatively writing pixels desired to be changed from the intermediate gradation to the white gradation is also possible.

  As described above, according to Example 4, in a display device that does not have a power source using a display element having semi-permanent memory properties such as cholesteric liquid crystal, power consumption during driving can be significantly reduced, and afterimages and It is possible to perform high-quality display in a short time without causing a decrease in contrast.

  Next, Example 5 will be described. In the fifth embodiment, a more detailed configuration and a wider range of applications of a display device having semi-permanent memory characteristics such as cholesteric liquid crystal will be described. In the fifth embodiment, the automatic display device holds a display medium having a semi-permanent memory property that retains display contents even when the power is turned off, information on a method of acquiring data to be displayed, and information on a display format of acquired display data. A display unit for acquiring display data in accordance with a data acquisition method, for example, an Internet connection unit, and a control unit for displaying the acquired data in accordance with a stored display format. Display data is acquired after being activated in response to a command to be displayed, data is displayed on a display medium having semi-permanent memory characteristics by adjusting the display format.

  FIG. 65 shows a configuration example of such an automatic display device. In the figure, the automatic display device 90 is different from the wireless display 21 shown in FIG. 7, for example, in addition to the control unit 35, the display unit drive circuit 39, and the memory display unit 40, in addition to the power supply 91, the Internet connection unit 92, and the battery 93. A timer 94 and a non-volatile memory 95.

  In FIG. 65, the automatic display device 90 is equipped with a host function and a connection mechanism to the Internet. When the power supply 91 is turned on, a page stored in the nonvolatile memory 95 is used by the operation of the Internet connection unit 92. Data is acquired, page data is displayed on the memory display unit 40 in accordance with the display format information stored in the nonvolatile memory 95, and the power is automatically turned off. The contents of the nonvolatile memory 95 can be freely rewritten from the outside, for example, from the wireless terminal side. Further, the automatic display device 90 can be automatically activated by the timer 94 backed up by the battery 93.

  The display means in claim 25 of the claims corresponds to the memory display section 40 of FIG. 65, the storage means corresponds to the nonvolatile memory 95, and the control means corresponds to the control section 35 and the display section drive circuit 39. The non-volatile storage means in claim 30 also corresponds to the non-volatile memory 95. The display data for a plurality of pages can be stored in the memory 95 and the display content of the memory-type display unit 40 can be rewritten. Even if the contents displayed on the screen are erased for some reason, the contents of the memory 95 can be used to restore the contents.

  FIG. 66 shows an example of the configuration of an automatic display device wired to a communication terminal 97 such as a PC or PDA. In the figure, both the automatic display device 90 and the communication terminal 97 are provided with wired interfaces 96 and 98 such as a USB and a contact IC card. When the automatic display device 90 is connected to a personal computer, a slot-in type, or a cradle type IC card reader / writer, the power supply starts and starts, and automatically enters a standby state after the same operation as in FIG. It becomes. When the connection with the computer is cut off, the power is cut off. The contents of the nonvolatile memory 95 can be freely rewritten from the host side, that is, the communication terminal 97 side via the wired interfaces 98 and 96. The automatic display device 90 can be always connected to the communication terminal 97 side, and can be automatically activated by the timer 94, for example.

  FIG. 67 is a configuration example of an automatic display device wirelessly connected to a communication terminal. Both the automatic display device 90 and the communication terminal 97 are provided with wireless interfaces 100 and 101 corresponding to wireless LAN, Bluetooth, etc., and the automatic display device 90 is activated in response to reception of an activation command from the communication terminal 97. Then, the same operation as in FIG. 65 is executed. A start-up command from the communication terminal 97 side is always monitored by a battery-backed monitor (not shown), and can be automatically started by a start command issued when a timer (not shown) mounted on the communication terminal 97 side expires. .

  FIG. 68 shows a configuration example of an automatic display device having a non-contact IC card interface. The automatic display device 90 includes a non-contact IC card interface 102 or an RF (Radio Frequency) ID interface, and the communication terminal 97, for example, an IC card reader / writer also includes a non-contact IC card interface 103.

  When the distance from the communication terminal 97 becomes a predetermined value or less, the automatic display device 90 is automatically activated and performs the same operation as in FIG. Non-contact IC cards include a proximity type with a short communication distance of about 10 cm but a high communication speed and a proximity type with a long communication distance of about 1 m but a low communication speed. Both types of IC card chips can be mounted on the automatic display device 90. In that case, since the power obtained from the communication terminal 97 side becomes small in a long distance where only the proximity type can operate, the power supply to the display unit is completely cut off, and the image data is transferred due to the limitation of the communication speed. Instead, it is realistic to transfer only character data.

FIG. 69 is an example of information on how to acquire data to be displayed and stored in the volatile memory 95 in FIG. 65, for example, and display format information on the acquired display data. In the figure, addresses 0 to 255 store a URL or a path name to a file as a method for acquiring data to be displayed. The content is, for example, xxxxxxx. com URL.
The data after address 256 is data related to the display format, and stores display format data similar to general print format data, such as the number of pixels on the display screen, designation of vertical or horizontal length, designation of equal magnification, enlargement, or reduction. Yes.

  In the fifth embodiment, not only data display but also data update date and time can be displayed. 70 and 71 are explanatory diagrams of the update date display format. In FIG. 70, an update date and time display section using segment pixels is provided on the display device side independently of the display section of the data itself, and a cholesteric liquid crystal can also be used as this display section.

  FIG. 71 also displays the update date and time in the data display section. This display is transmitted from the host (communication terminal) side in a form added to the display data and displayed. In contrast, in FIG. 70, for example, display data and update date / time information are independently transmitted from the host side. Since the update date and time is displayed, the user can immediately determine when the information is.

  A configuration example of the automatic display device according to the fifth embodiment will be further described. First, the memory display unit 40 shown in FIG. 65 or the like is optimally a semi-permanent memory such as a cholesteric liquid crystal as described above, but does not have such a property, for example, several hours or one day. It is also possible to combine an element capable of holding the memory contents in such a unit or an element having no memory property and a nonvolatile memory.

  In this case, it is possible to have one page or a plurality of pages of the nonvolatile buffer memory. When the display element has a semi-permanent memory property, a buffer memory is not necessarily required. However, by mounting a buffer memory for one page, a part or all of the display contents of the display element is, for example, an upper limit of memory retention temperature. Even if it disappears because it exceeds the limit, the display contents can be restored immediately. In addition, by installing a buffer memory for a plurality of pages, display contents can be switched immediately.

  The automatic display device can also prohibit rewriting of data displayed on the memory display unit 40 in FIG. 65, for example. This rewrite prohibition method may be a hardware method such as a write prohibition method in a flexible disk, but it is naturally possible to use a software method.

  Also, if the automatic display device is acquiring display data from the outside and the communication with the external device is interrupted for some reason, the acquisition of the display data that has not been completed when communication with the external device is resumed. Incomplete data can also be acquired. Such a method is widely used in download support tools such as freeware. The RESUME function in such a support tool can be used to acquire data that has not been acquired.

  Furthermore, the automatic display device according to the fifth embodiment may include a history storage function regarding a display data acquisition method. Such a function is not always necessary, but it is easy to refer to data displayed in the past by providing such a function. Such a history may be stored in the non-volatile memory 95 in FIG. 65 or may be stored outside via the host.

  Finally, a wide range of applications of the automatic display device according to the fifth embodiment will be described. First of all, such an application example will be briefly described. Although a mobile terminal screen can be transferred to an automatic display device as it is, a high-definition, large-screen data corresponding to the mobile terminal screen is separately constructed, and the automatic display device Can also be transferred to.

  Further, in order to install the automatic display device driver on the mobile terminal from the automatic display device, the automatic display device may include an installer for the mobile terminal. In general, a mobile terminal has a small amount of memory, and a memory can be effectively used by installing a driver when necessary and deleting it when it is no longer needed.

  Further, the automatic display device has a refill shape corresponding to a replaceable page in the system notebook, and can display data on both sides of the refill. In this case, it is possible to install antennas on both sides, provide a magnetic shield layer in the middle, compare the voltages generated on the two antennas, and rewrite the display data on the side where the high-voltage antenna is installed first. it can.

  Furthermore, in the automatic display device, only the display unit including the display panel and the driver LSI can be removed, and a function for erasing the data in the display panel and the buffer memory can be provided. It is a display area, and when the display data is updated, the advertisement data can be downloaded by a predetermined procedure and displayed there.

  Such application examples will be further described with reference to the drawings. The automatic display device (wireless display sheet and wireless display card) of FIG. 72 is equipped with a non-contact type IC card interface (antenna, IC chip). When the automatic display device is brought close to a mobile phone, digital camera, or PDA equipped with an IC card reader / writer, the automatic display device requests transfer of screen data. An automatic display device driver is installed in a mobile phone or the like, and the mobile screen data is transferred as it is or a high-definition / large screen data corresponding to the mobile screen data is constructed and transferred to the automatic display device. The automatic display device performs display drive control according to the power supplied from the mobile phone as described above, displays screen data on the display panel, and automatically enters a standby state.

  By simply bringing a sheet-like object close to a mobile phone, you can zoom in on a map, display an entire long email, or display the content you want to take notes. The mobile phone automatic display device driver can also be installed from the automatic display device.

  When the automatic display device shown in FIG. 72 is brought close to a notebook computer equipped with an IC card reader / writer, the automatic display device requests transfer of print data. An automatic display device driver is installed in the notebook computer, and print data is transferred to the automatic display device by a normal printing procedure. The automatic display device performs display drive control according to the power supplied from the notebook personal computer, displays the print data on the display panel, and automatically enters a standby state.

  The automatic display device may be in the form of a system notebook refill. In that case, both sides may be displayed. By installing antennas on both sides and providing a magnetic shield layer in the middle, it is possible to identify which display side the IC card reader / writer is on. It is preferable to prioritize display data processing on the side where the IC card reader / writer is present.

  The automatic display device as a second display for PC in FIG. 73 is equipped with a USB interface. When the automatic display device is connected to the desktop personal computer, the automatic display device requests transfer of screen data as the second and subsequent displays. An automatic display device driver is installed in the desktop personal computer, and screen data is transferred to the automatic display device in the same manner as a normal display. The automatic display device displays screen data on the display panel, automatically requests transfer of the next screen data, and repeats a series of operations.

  It is well known that working efficiency increases when a plurality of displays are used. Since the automatic display device is thinner and lighter than a normal display, can be used in a free layout, and is less expensive than a normal display, 4 to 5 sheets may be used simultaneously. It is an indispensable item to read the nesting online manual comfortably.

Next, the automatic display device in this embodiment is equipped with a wireless LAN interface and a battery. The automatic display device is automatically activated when the owner's desktop personal computer is activated and the owner's authentication is completed. Requests the transfer of staff schedule data to the desktop PC. The automatic display device driver is installed in the desktop personal computer, and the staff schedule data is transferred. The automatic display device displays the staff schedule on the display panel and automatically enters a standby state. In the standby state, only the display unit of the automatic display device can be removed.
There are many people who print the staff schedule every day. About 250 sheets of paper are consumed per person per year. By using the automatic display device, it is possible to save the trouble of daily printing the staff schedule, and to reduce paper consumption and paper dust generation.

  The automatic display device in this embodiment is equipped with a non-contact type IC card interface (antenna, IC chip). When the automatic display device comes close to a mobile phone equipped with an IC card reader / writer, the automatic display device requests transfer of newspaper articles. An automatic display device driver is installed in the mobile phone, and a newspaper article is downloaded from a newspaper company homepage and transferred to the automatic display device. The automatic display device performs display drive control according to the power supplied from the mobile phone, displays a newspaper article on the display panel, and automatically enters a standby state.

  It is very convenient to read the latest newspaper articles just by bringing a sheet-like object close to a mobile phone. A similar technique can be applied to electronic books. You don't have to download it in advance, so you can start reading paperback books and magazines that you noticed, for example, in a train strap advertisement. Compared to electronic books that are downloaded in advance to an SD (Secure Digital) card or the like for copyright protection or the like, it is much more convenient and comfortable.

  The automatic display device in this embodiment is equipped with a wireless LAN interface and a battery. The automatic display device starts automatically when the owner's desktop personal computer is started. Request the transfer of newspaper articles to a desktop computer. An automatic display device driver is installed in the desktop personal computer, and newspaper articles are downloaded from a newspaper company's website and transferred to the automatic display device. The automatic display device displays newspaper articles according to the size of the display panel (A6 to A3 spread) and automatically enters a standby state. In the standby state, only the display unit of the automatic display device can be removed.

  Using an automatic display device eliminates the need for printing, delivery, and delivery to homes, so the subscription fee is cheaper than conventional newspapers, and you can read articles that are much newer than traditional newspapers. Paper consumption and paper waste generation can also be reduced.

  A large number of automatic display devices shown in FIG. 74 are affixed in a train car, and each is equipped with a Bluetooth interface and a battery. In response to an activation command from a Bluetooth-equipped laptop computer brought into the vehicle, one of the automatic display devices is activated by identifying the command with an IC and requests the transfer of advertisement data. An automatic display device driver is installed in the notebook personal computer, and advertisement data to be displayed on the activated automatic display device is transferred. The automatic display device displays an advertisement on the display panel and automatically enters a standby state. A series of operations is repeated until updating of the display contents of all automatic display devices is completed.

  By using the automatic display device, it is possible to reduce the printing cost, the pasting cost, the paper consumption, and the amount of paper dust generated. A personal computer can be permanently installed in the vehicle, and the content of the advertisement can be completely switched according to the time zone and the area where the train is running. A similar technique can be applied to a price display in a store such as a supermarket.

  Next, a number of automatic display devices used for building wall advertisements are affixed to the wall surface of the building, and each is equipped with a Bluetooth interface and a battery. A Bluetooth-equipped personal computer is installed in a building and is connected to antennas installed at a plurality of locations on a wall surface. One of the automatic display devices is activated in response to an activation command from the personal computer, and requests the transfer of advertisement data. An automatic display device driver is installed in the notebook personal computer, and advertisement data to be displayed on the activated automatic display device is transferred. The automatic display device displays an advertisement on the display panel and automatically enters a standby state. A series of operations is repeated until updating of the display contents of all automatic display devices is completed. When a large screen is displayed by a plurality of automatic display devices, each unit requests only the image data of the portion that it is in charge of, so that the image clipping process is easy.

  By using the automatic display device, the printing cost and the pasting cost can be reduced. Depending on the time of day, the content of the advertisement can be completely switched. A similar technique can be applied to the station timetable.

  A large number of automatic display devices used as conference distribution materials shown in FIG. 75 are installed in the conference room, and each is equipped with a Bluetooth interface and a battery. One of the automatic display devices is activated in response to an activation command from a Bluetooth-equipped notebook personal computer brought into the conference room, and requests the transfer of conference materials. An automatic display device driver is installed in the notebook computer, and conference materials to be displayed on the activated automatic display device are transferred. The automatic display device displays the conference material on the display panel and automatically enters a standby state. A series of operations is repeated until the display of all automatic display devices is completed.

  By using the automatic display device, printing cost, bookbinding cost, paper consumption, and paper dust generation can be reduced. Materials that are needed in a hurry during the meeting can be quickly distributed. Furthermore, since confidential materials can erase data in the display panel and buffer memory at the end of the conference, security can be increased by using an automatic display device.

  Next, an example of use for mobile display with an advertisement display function will be described. This is similar to the enlarged screen display (FIG. 72) of the mobile device, except that a part of the display screen is a fixed advertisement display area. When the display data is updated, the advertisement data is downloaded from a predetermined URL and displayed in the advertisement display area. Since it is effective as a sales promotion tool, there is a high possibility that companies will distribute a large number of automatic display devices free of charge.

  As described above, according to the fifth embodiment, the automatic display device is activated without operating the personal computer or the like, for example, by bringing the non-contact IC card close to the IC card reader / writer built in the personal computer or PDA. Realizes an automatic display device using convenient electronic paper that can display information, and the display does not disappear even when the power is turned off, and the display content can be rewritten arbitrarily. Is done.

  The present invention naturally applies to the manufacturing industry of mobile devices including IC cards, electronic paper, liquid crystal display elements, and mobile terminals and digital cameras, and in all industries using these display devices, display elements, and mobile devices. Is available.

It is a figure which shows the structure of the prior art example of a cholesteric liquid crystal element. It is a figure which shows the prior art example of the drive waveform with respect to a passive matrix type | mold element. It is FIG. (1) which shows the problem of the prior art example of a cholesteric liquid crystal drive system. It is FIG. (The 2) which shows the problem of the prior art example of a cholesteric liquid crystal drive system. 1 is a block diagram illustrating a principle configuration of an information display system according to the present invention. It is a principle block diagram of the display device of the present invention. 1 is a block diagram illustrating a configuration of a first example of a display system in Embodiment 1. FIG. 6 is a block diagram illustrating a configuration of a second example of the display system in Embodiment 1. FIG. It is explanatory drawing of the same screen display mode in the system of FIG. It is explanatory drawing of the different screen display mode in the system of FIG. It is explanatory drawing of the screen selection transmission mode in the system of FIG. It is explanatory drawing of the data display on a wireless display. It is explanatory drawing of the mechanical attachment mechanism (the 1) by the side of a portable terminal. It is explanatory drawing of the mechanical attachment mechanism (the 2) by the side of a portable terminal. It is explanatory drawing of the mechanical attachment part (the 1) by the side of a wireless indicator. It is explanatory drawing of the mechanical attachment part (the 2) by the side of a wireless indicator. It is explanatory drawing of the magnet and a magic tape as an attachment mechanism by the side of a terminal. It is explanatory drawing of the magnet and a magic tape as an attachment mechanism by the side of a wireless indicator. It is a figure which shows the example of the wearable display system using a wireless display. It is explanatory drawing of the planar state of a cholesteric liquid crystal. It is explanatory drawing of the focal conic state of a cholesteric liquid crystal. It is a figure which shows the example of the reflection spectrum of a cholesteric liquid crystal. It is explanatory drawing of the planar drive waveform with respect to a cholesteric liquid crystal. It is explanatory drawing of the focal conic drive waveform with respect to a cholesteric liquid crystal. It is a figure which shows the response characteristic of a cholesteric liquid crystal. It is a structural example of a reflective liquid crystal display element using a cholesteric liquid crystal. It is explanatory drawing of the example of the segment display using a cholesteric liquid crystal. It is a figure which shows the liquid crystal separation structure in a matrix substrate. It is a figure which shows the isolation | separation structure of two liquid crystals. It is a figure which shows the example of the pixel structure in FIG. It is explanatory drawing of formation of the subdot in FIG. It is a figure which shows the isolation | separation structure of three liquid crystals. It is a figure which shows formation of the dot in FIG. It is a figure which shows formation of the subdot in FIG. It is a figure which shows the example of a superimposed display of printed matter and a variable type display element. It is a figure explaining the display state in FIG. It is a figure which shows the example of a superimposed display for the purpose of merchandise sales. It is a figure which shows the example of a superimposition display corresponding to a restaurant menu. It is a figure which shows the example of a superimposition display corresponding to a schedule table. It is a figure which shows the example of a superimposition display corresponding to a map. It is a figure which shows the example of a superimposition display corresponding to a problem collection. It is a figure which shows the example of a superimposition display corresponding to the simulation of a bank loan. It is a figure which shows the example of power supply circuits, such as a non-contact IC card in Example 3. FIG. It is a figure which shows the example of the power supply circuit which provided the power supply for a logic and a display independently. It is a figure which shows the structural example of the power supply circuit with respect to liquid crystal driver LSI which requires many types of voltage values. It is a structural example of the circuit which restrict | limits the electric power supply to a display part according to an electric power supply amount. It is a structural example of the clock output circuit which extends the drive period of a display part according to electric power supply amount. It is a structural example of a circuit that outputs an image display prohibition signal according to the amount of power supply. It is a structural example of the current limiting circuit with respect to the power supply for a display. It is an example of the crest value in the drive waveform of a cholesteric liquid crystal. It is an example of the crest value in the drive waveform when the pulse width is widened. In this example, the peak value of the driving waveform is linearly changed according to the temperature. It is a structural example of the temperature compensation circuit for implement | achieving the characteristic of FIG. FIG. 10 is a block diagram of a configuration example of a liquid crystal display element driving driver in Example 4. It is explanatory drawing of the screen rewriting system in Example 4. FIG. It is a time chart of the screen rewriting system of FIG. It is a figure which shows the polarity inversion system of the liquid crystal element drive waveform in Example 4. FIG. It is explanatory drawing (the 1) of the effect of the drive system in Example 4. FIG. It is explanatory drawing (the 2) of the effect of the drive system in Example 4. FIG. It is explanatory drawing (the 3) of the effect of the drive system in Example 4. FIG. It is explanatory drawing of the skip drive system as an image writing system. It is a process flowchart of a skip drive system. It is a figure which shows the 1st write-in result in a ternary write system. It is a figure which shows the 2nd writing result in a ternary writing system. FIG. 10 is a block diagram of a configuration example of an automatic display device according to a fifth embodiment. It is an example of a structure of the automatic display apparatus wire-connected with a terminal etc. It is an example of a structure of the automatic display apparatus wirelessly connected with a terminal etc. 2 is a configuration example of an automatic display device having a non-contact IC card interface. It is a figure which shows the example of the information of a data acquisition method, and the information of a data display format. It is explanatory drawing (the 1) of the update date display format of data. It is explanatory drawing (the 2) of the update date display format of data. It is explanatory drawing of the automatic display apparatus which displays screens, such as a terminal. It is explanatory drawing of the automatic display apparatus as a second display. It is explanatory drawing of the automatic display apparatus which displays advertisement data. It is explanatory drawing of the automatic display apparatus used as a meeting distribution material.

Claims (3)

A first display element having a transmission mode and a reflection mode and capable of switching display contents;
A display device comprising: a reflective second display element that displays a fixed image or a fixed character and is capable of visually recognizing the content of the display through the first display element.   The display device according to claim 1, wherein the second display element is a printed matter or an object handwritten with a character / image, and is detachable from the first display element.   The first display element has a function of changing a display range according to a position and a shape of a fixed image or a fixed character on the detachable second display element. 2. The display device according to 2.

Images