KR100944482B1 - Display apparatus and method for driving a display element - Google Patents

Abstract

The present invention enables mechanical detachment, for example, between a display device 1 without a power supply and an information display device 2 such as a wireless terminal that sends display data or power to the display device 1, thereby enabling mechanical detachment. For the construction, the apparatus 1 includes a display unit 3 capable of continuing the display even after the power supply is cut off, a short range communication unit 4 receiving the display data from the outside, and a display control unit 5 for the received data. The device 2 has a storage unit 6 for storing display data, and a communication unit 7 for sending display data to the device 1 side, for example, in which the device 2 attaches the device 1 to a magnetic device. It further comprises a mechanical detachable portion.

Description

Display device and display device driving method {DISPLAY APPARATUS AND METHOD FOR DRIVING A DISPLAY ELEMENT}

The present invention relates to an information display system constituted by, for example, a mobile device and an apparatus for displaying 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 composed of a wireless terminal and a contactless IC card, a display element using a cholesteric liquid crystal such as a display maintained even when the power supply is cut off, a driving method thereof, and an electronic paper having such a memory property It relates to a display device.

There is a demand to expand and display display information of mobile phones, PDAs, digital cameras, and the like. As one method for this purpose, a method of enlarging only a part of the screen of the terminal is adopted. In this method, since the whole image cannot be viewed at a time, it is troublesome to scroll. As another method, there is a method in which near field communication functions such as Bluetooth, infrared ray, wireless LAN, etc. are installed in a portable terminal, and image information is transferred and displayed wirelessly to a large screen display mounted on a personal computer, a TV, or the like. . Instead of wireless transmission, a method of transferring an image by a wired interface connection function such as USB or IEEE1394 and displaying a large screen is adopted. However, under the mobile environment such as the outside, such an enlarged display method has a problem for mobile devices due to the need for an AC power source or a certain battery, a heavy device, and the like.

As a display method under a mobile environment for avoiding this, it is conceivable to connect an enlarged display device which is lightweight and low power consumption to a portable terminal. This approach has been proposed using light weight, low power electronic paper. In this method, since the contact is electrically connected, 1) the size of the mobile terminal is substantially increased in the connection at all times, and 2) deterioration due to fatigue of the electrical contact occurs when connecting only during use. 3) after disconnecting the connection. There arises a problem that the display is lost or a battery is mounted in an indicator for preventing the display from being lost. The battery is not only inconvenient for battery replacement or battery feeding of the indicator, but also increases the thickness and weight of the indicator. To solve these problems, the terminal itself is required to have a mobile display system which is substantially small, has an enlarged display screen, and is hands free.

There is also a demand to print out arbitrary display information such as a mobile phone, a PDA, a digital camera, etc. from a business trip or a visited place. On the other hand, although a battery-powered mobile printer apparatus is sold, there exists a problem of weight and volume, and also the spread of paper and a battery. Instead of such a printer device, it is expected to make the display spaced apart from the portable terminal, in the absence of a printer and substantially equivalent to a paper print.

For this display, there is the following document regarding a prior art using a contact IC card or an RF (Radio Frequency) tag or a noncontact IC card using near field radio. Patent document 1 discloses an IC card capable of rewriting display contents of a display unit.

In patent document 2, patent document 3, and patent document 4, the IC card which has a power supply for a display is disclosed, the solar cell in patent document 2, the lithium battery in patent document 3, and the auxiliary power supply in patent document 4, for example. Solar cells are used.

In patent document 5 and patent document 6, the memory-type display element which can hold | maintain a display content even if a power supply is cut | disconnected without using auxiliary power supplies, such as a solar cell, is used. In patent document 5, a ferroelectric liquid crystal display element and an electrochromic display element are used, for example, and in patent document 6, use of a cholesteric nematic phase transition type liquid crystal is proposed.

<Patent Document 1>

Japanese Utility Model Publication No. 7-30384 `` IC Card ''

<Patent Document 2>

Japanese Patent Laid-Open No. 62-242592 Publication "IC Card"

<Patent Document 3>

Japanese Patent Laid-Open No. 63-3393 "Card Processing System with Display Function"

<Patent Document 4>

Japanese Patent Laid-Open Publication No. 2003-6590 `` Information recording medium with auxiliary power source ''

<Patent Document 5>

Japanese Patent Laid-Open No. 10-93484 "Data Carrier"

<Patent Document 6>

Japanese Patent Application Laid-Open No. 2000-113137 "Contact Information Recording Display Method and Non-Contact Information Recording Display Method"

In this type of short-range wireless, information is exchanged with a non-powered IC card wirelessly from an IC card reader / writer mounted in a fixed terminal. If the card and the writer are in close proximity, it is possible in principle to provide the display recording power and the display information to record the display. However, conventionally, there is no convenient display system linked with a mobile terminal using a non-contact wireless method, and in reality, there are some technical reasons, for example, insufficient recording power, voltage, memory retention, and writing speed. Therefore, display on a contactless IC card has not been realized yet. Using such a non-contact radio method, a display system or electronic paper having a good convenience suitable for a mobile application in which arbitrary display information is transmitted from a portable terminal to be enlarged and displayed is desired.

The electrophoretic method, which is a strong memory medium, suspends white or black charged fine particles in a white liquid in a capsule and attracts particles by static electricity. Therefore, in principle, memory retention, high speed driveability, and low voltage driveability are opposed. It is difficult to use this for non-powered recording. Electrochromic is a memory display method using chemical change, but the recording power is large, and wireless recording is difficult. In addition, the memory liquid crystal has a problem that the ferroelectric memory liquid crystal medium has a high recording speed, but because the polarizing film is used, the brightness of the reflective white display is insufficient and the display is lost due to mechanical shock.

As a memory liquid crystal, the cholesteric nematic phase transition type liquid crystal element proposed by the above-mentioned patent document 6 is mentioned. This material uses light scattering, but has a problem of low contrast and a problem of requiring a bias voltage in order to keep the display stable.

On the other hand, cholesteric liquid crystals (including chiral nematic liquid crystals) have selective reflectivity for selectively reflecting light of a certain wavelength, and reflect light wavelengths according to the layer pitch of the liquid crystal, thereby exhibiting a single color. Therefore, in order to multicolor, the laminated structure like following patent document 7 is proposed.

<Patent Document 7>

Japanese Patent Laid-Open No. 9-160066 "reflective liquid crystal display device"

1 shows a conventional example of a liquid crystal element having a laminated structure using a cholesteric liquid crystal. In FIG. 1, three layers of liquid crystals 204, 205, and 206 are inserted between the upper and lower substrates 201 and adhered through the transparent electrodes 202, respectively. There is much light, and the contrast of a display falls. There are also a lot of structural members, there is a problem of being an expensive device.

That is, the cholesteric liquid crystal exhibits a 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 mix, they become neutral or anti-reflective. As a method of separating the liquid crystal, there is also a capsule structure in which the liquid crystal is trapped in the capsule, but due to the influence of the interface and thickness of the capsule, the contrast decreases due to the noise light and the driving voltage is increased, which is not preferable for use in a display device. There is a problem that it is also difficult to arrange a desired capsule in the pixel.

Next, the problem regarding the power supply circuit in the case of using such a cholesteric liquid crystal for a non-powered display device, such as a non-contact type IC card or electronic paper, is demonstrated. In general, in a non-contact non-contact IC card or the like, a method of receiving and displaying electric power for display together with data from a portable terminal, an IC card reader / writer, or the like, for example, by using near field radio, the value of the electric power that can be used as a power source. Since it is small, it is necessary to restrict current, for example, to a power supply circuit.

In particular, in the cholesteric liquid crystal, two types of drive waveforms having different crest values are required for driving in each of a planar state and a focal-conic state as two stable states, as described later. In addition, the driving voltage to the planar state requires about 40 V, which is quite high compared to other display elements. For this reason, 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 very difficult to make the power supply circuit within a thickness of about 1 mm.

2 shows a conventional example of drive waveforms for a passive matrix element. As shown in Fig. 2, the driving voltages for the planar and focal-conic states must be applied to the pixels on the lines of the selection level in accordance with the on and off states of the signal lines, and on the lines of the non-selection levels. It is necessary to apply a voltage that does not change the state recorded at the time of selection to the pixel. In the commercially available STN liquid crystal driver LSI, for example, five types of voltages are required, resulting in an increase in the cost of the power supply circuit.

Then, for example, when the contactless IC card is operated only by power supply 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, there is a problem that if the display unit is always operated, the communication distance is considerably shortened compared to the normal noncontact IC card without the display unit, or the power required for the noncontact IC card chip temporarily becomes short during communication, resulting in unstable operation. For this problem, display control according to the power supply amount is required.

In addition, the power for driving the passive matrix cholesteric liquid crystal is relatively small except at the time of startup, and can be sufficiently operated by the power supplied from the weak output non-contact IC card reader / writer mounted on a PDA or the like. However, in the conventional driver LSI, moving image display is premised, and the impedance of the transistor at the last stage is low, so that a very large instantaneous current (5 to 10 times of normal operation) flows in the transient state at startup. . For this reason, there is a problem that the existing driver LSI may not be activated even when the electric power is supplied several times during normal operation.

It is not very costly to prepare a power supply with a large supply capacity only for startup, and it is impossible to supply 5 to 10 times the power during normal operation with a weak output reader / writer mounted in a PDA. . For this reason, it is indispensable to develop a control method for stably starting the existing driver LSI at a power supply close to that of normal operation as much as possible.

Furthermore, as described above, in the cholesteric liquid crystal, two kinds of driving waveforms having different crest values are required to correspond to planar driving and focal conic driving, respectively, and the crest values need to be changed according to temperature. For this reason, when the operating temperature range is to be widened, there is a problem that the crest value of the planar drive at high temperature and the crest value of the focal conic drive at low temperature are approached, making it difficult to secure the crest margin. In order to broaden the application range of the cholesteric liquid crystal, a method for securing a crest margin over a wide operating temperature range is desired.

Next, the problem of the high speed drive of the cholesteric liquid crystal will be described. As described above, the driving of the cholesteric liquid crystal includes the planar driving and the focal conic driving. In general, the pulse voltage of the alternating current is used, although it depends on the material of the liquid crystal, the period of almost 20 ms, that is, 20 ms / line When recording at a higher speed, the transition to the focal conic state is insufficient as shown in FIG. 3, and there is a problem that the contrast is greatly reduced as shown in FIG. If recording is performed at a slower speed than this, sufficient contrast can be obtained. However, even for a screen having a QVGA size (320 x 240 dots), it takes about 5 seconds to complete recording, and there is a problem that the waiting time until completion of display is long.

As a high speed driving method to solve this problem, a driving method as described below has been developed. However, these methods have various problems in wireless driving using weak electromagnetic waves as in the non-contact IC card of the present invention. . Hereinafter, a representative high speed driving method under the use of cholesteric liquid crystal and its problems will be described.

In Patent Literature 8, a recording method named FCR (Focal Conic Reset) method which first applies a reset voltage for transitioning to the focal conic state to all the scan electrodes, and then sequentially selects the scan electrodes one by one. Although a batch reset for selecting all scan electrodes is selected for all scan electrodes, it is not suitable for wireless driving because the power consumption at that time is enormous. In particular, the power consumption is large when transitioning to the focal conic state.

In addition, Patent Document 9 also uses the method of homeotropic reset, and the power consumption at the time of reset is very large as described above. For this reason, wireless driving is not practical.

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

In addition, the MLA (multi-line access) method, which is widely known as STN driving, also drives a large number of lines collectively, so that the power consumption is large, which is not suitable for wireless driving. In addition, the driving circuit is complicated and expensive.

Since an image with a high spatial frequency such as a checkered pattern consumes significantly larger power, the above driving method becomes more and more disadvantageous for wireless driving.

Afterimages remain in the planar reset.

Patent Document 11 discloses, for example, a method of detecting a plurality of lines containing the same recording line data and simultaneously writing the plurality of lines, but the method of determining the maximum number of lines for simultaneous recording is unclear.

<Patent Document 8>

Japanese Patent Laid-Open No. 11-326871 "Drive Method of Liquid Crystal Display Element"

<Patent Document 9>

Japanese Patent Application Laid-Open No. 2002-6287 "Drive Method and Drive Device for Memory-Cholesteric Liquid Crystal Display Device"

<Patent Document 10>

Japanese Patent Laid-Open No. 2002-55327 "Drive method of a liquid crystal display device and a liquid crystal display element"

<Patent Document 11>

Japanese Patent Laid-Open No. 10-20809 "Image Display Method and Apparatus"

As in the present invention, in the case of handling the drive for a non-contact IC card, for example, high-speed driving up to a μs order is not particularly necessary, and a high-speed driving method of its own high quality is required in response to the small supply power in wireless. .

Finally, the problem of the display apparatus using the electronic paper using the above cholesteric liquid crystal etc. is demonstrated. In other words, development of a display device using electronic paper having both a feature that the display does not turn off at least immediately even when the power supply is turned off and a feature that the display content can be arbitrarily rewritten is being progressed. There was a problem that the function was not provided.

That is, since the automatic display device does not have information on when, where and how to acquire the data to be displayed or information on the display form of the acquired display data, the display data is automatically displayed according to the information of the acquisition method. There has been a problem that an automatic display device which automatically acquires and automatically displays a standby state according to the information of the display form is not provided.

A first object of the present invention is to provide a total information display system by enabling mechanical detachment between, for example, an information display apparatus that does not have a power source and a wireless terminal that sends arbitrary display data or power to the information display apparatus. will be.

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

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

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

The fifth object is to preserve information on the method of acquiring data to be displayed and information on the display form of the display data, to automatically acquire data from the outside, and display the data to automatically return to the standby state. It is also possible to provide an automatic display device having a wide range of applications.

The information display system of the present invention is constituted by a display device and a display data holding device. The display device displays the display means corresponding to the data received by the local area communication means and the local area communication means for short-range communication in order to receive any data to be displayed from the outside, and the display means for continuing the data display even if the power is cut off. And display control means for controlling the display of the means.

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 in a short range.

Mechanical detachment means for mechanically detaching the display device and the display data holding device may be provided, and the display data holding device, for example, sending data displayed on the display unit on the portable terminal to the display device side for enlarged display. .

The display element of this invention, ie, the display element in which a liquid crystal is inject | poured between two board | substrates, is provided with the partition which has a structure for not contacting the liquid crystal of the several colors inject | poured between two board | substrates.

In addition, the display device of the present invention has a transmission mode and a reflection mode, and displays the first display element and the fixed image or the fixed character which can be switched between the display contents, so that the display contents can be visually recognized through the first display element. A reflective second display element is provided.

In the display device of the present invention, for example, 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 is changed with temperature. In addition, the display device of the present invention has a coil provided to receive a high frequency magnetic field from the outside. The coil includes an intermediate tab, one end of the coil is grounded, and a resonance capacitor is connected between the intermediate tap and the ground. Logic power supply means for rectifying the high frequency voltage generated at both ends of the resonant capacitor to impart a voltage to a circuit other than the display, and rectifying the high frequency voltage between the other end of the coil and the intermediate tap to impart a display voltage. And display power supply means.

In the element driving method of the present invention, in a matrix display device using cholesteric liquid crystals, a part of the scan electrodes is set to the reset line in the selected state, the write line, and the stop line in the non-selected state, respectively, to reset the line and the stop. A driving method is used in which a write data signal is applied to the signal electrode side while shifting lines and recording lines, respectively.

Further, as the display element driving method of the present invention, in the matrix type display device as described above, among a plurality of lines on the display screen, a plurality of lines having the same data pattern to be displayed are detected, and a plurality of detected lines are simultaneously selected. In this way, a driving method is used in which batches of the same pattern are recorded by applying data of the same pattern to the signal electrodes.

The display device of the present invention includes, for example, storage means for storing data about display means capable of continuing data display, information about a method of acquiring data to be displayed, and information about a display form of acquired display data, and the like. Control means for controlling the acquisition of display data from the outside and the display on the display means of the display data in accordance with the storage contents of the storage means.

As described above, according to the present invention, for example, a display device is constructed by using a cholesteric liquid crystal display element or the like which can continue displaying data even when the power supply is cut off, and the display device and the display device side are provided with the display data. An information display system is configured by a display data holding device that is supplied at the same time, for example, a portable terminal.

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

The display device 1 includes, for example, a display unit 3 capable of continuing to display data even when the power supply is cut off, and a short-range communication unit 4 and a short-range communication unit 4 which communicate at a short distance in order to receive data to be displayed from the outside. In response to any data received by the control unit, a display control unit 5 for controlling the display of the display unit 3 is provided.

The display data holding device 2, for example, the portable terminal, transmits the display data to the display device 1 in correspondence with the storage unit 6 holding the display data and the storage contents of the storage unit 6 at least in a short range. The communication part 7 is provided.

Unlike the communication unit 7, the display data holding device 2 is capable of remote communication, and further includes a remote communication unit for acquiring display data from the outside, and the communication unit 7 displays the display data acquired by the remote communication unit. It may also transmit to the device 1 side.

The display device 1 may further include a mechanical detachable part for attaching the magnetic device to a human body or clothes.

The display data holding device 2 may further include a display portion having a display area smaller than the display portion 3 on the display device 1 and a mechanical detachable portion for attaching the display device 1 to the magnetic device. While the data holding device 2 further includes a display unit as described above, the display device 1 may further include a mechanical detachment unit for attaching the display data holding device 2 to the magnetic device.

In addition to the data to be displayed from the display data holding device 2 side, the near field communication unit 4 on the display device 1 may further receive power for display and display control information.

The display element of this invention is equipped with the partition which has a structure for not contacting the liquid crystal of a several color injected between two board | substrates.

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

In addition, the display device of the present invention has a transmissive mode and a reflective mode, and can display the first display element and the fixed image or the fixed character which can be switched between the display contents and visually recognize the display contents through the first display element. A reflective second display element is provided.

The second display element is a printed matter or an object on which a character or an image is drawn by hand and can be attached to or detached from the first display element, and displayed according to the position and shape of the fixed image or fixed character on the second display element on which the first display element is detachable. It is also possible to have a function that makes it possible to change the range.

In addition, the display device of the present invention includes a temperature compensator for changing 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 this temperature compensating part has a peak value of the peak value of the drive waveform at the lower limit of the temperature range and an upper limit value of the peak value of the drive waveform at the upper limit of the range. It is also possible to change it corresponding to the straight line which connects the average value of and a lower limit.

In addition, the display device of the present invention includes a coil installed to receive a high frequency magnetic field from the outside, and rectifies the high frequency voltage induced in the coil and a display power supply unit for rectifying the high frequency voltage induced in the coil to impart a display voltage. And a logic power supply unit for supplying 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, and a resonance capacitor is connected between the intermediate tap and the ground, the logic power supply rectifies the voltages at both ends of the resonance capacitor, and the display power supply coil It is also possible to rectify the voltage between the other end of the and the middle tap.

In addition, the display device includes a display unit which receives electric power from the outside in a non-contact manner and performs data display using the electric power, and has a display function control unit that limits the display function of the display unit in response to the amount of power supplied from the outside.

In addition, the display device is provided with a display power source that receives power from a non-contact source from outside and uses a portion of the power and a logic power source that supplies power to a circuit other than the display unit by using a portion thereof. Correspondingly, a current controller for limiting the output current of the display power supply.

In the display element driving method of the present invention, in a matrix type display device using cholesteric liquid crystals, a part of the scan electrode is set to the reset line in the selected state, the write line, and the stop line in the non-selected state, respectively, to reset the line and the stop. The write data signal is applied to the signal electrode side while shifting the line and the write line, respectively.

In this case, it is also possible for the write alternating current signal for the reset line and the write line in the selected state to be inverted in polarity within a time corresponding to one line and to have a period of time corresponding to two lines.

Next, in the display device driving method of the present invention, in the matrix type display device, a plurality of lines having the same data pattern to be displayed are detected among a plurality of lines on the display screen, and the plurality of detected lines are simultaneously selected to select data of the same pattern. By collectively recording the same pattern data by applying it to the signal electrode, the maximum value of the number of the plurality of lines in which the batch recording is performed may be made in inverse relationship with the spatial frequency of the same pattern data.

Further, in the display element driving method of the present invention, the step of converting the image data to be recorded in the liquid crystal element into the image data of n gradation, extracting the pixels of each gradation level after the conversion, firstly with respect to the extracted pixel Sub-image 1 formed by converting the low gray level 1 (i.e. black level) and the nth low gray level n (i.e., the white level) to the black level and the white level, respectively, the first low gray level Sub-image 2 formed by converting the gradation level 2 from the first to the second lowest luminance to the black level and combining it with the gradation level n; Sub-image (n-1) formed by converting from the gradation level 1 having the lowest luminance to the (n-1) th gradation level (n-1) having the lowest luminance to the black level and combining it with the gradation level n Forming a sub image 1, starting with the recording of the sub image 1; In this case, a recording method is used in which sub-pictures (n-1) are recorded in order to obtain display of n gray levels.

Converting the image data to be recorded in the liquid crystal element into n-gradation image data; extracting pixels of each gradation level after the conversion; and gradation level having the highest luminance with respect to the extracted pixel. Sub image 1 formed by converting the first and nth gradation level n to the white level and the black level, respectively, from the first gradation level 1 to the second highest gradation level 2 and the second gradation level 2 to the back level Sub image 2,... A sub-image (n-1) formed by converting from the gradation level 1 of the first highest brightness to the (n-1) th gradation level (n-1) of the first highest brightness to a back level and combining it with the gradation level n Forming the sub-picture 1, starting with the recording of the sub-picture 1; In this case, a recording method is used in which sub-pictures (n-1) are recorded in order to obtain display of n gray levels.

6 is a principle block diagram of the display device of the present invention. In FIG. 6, the display device 10 includes a display unit 11 which performs data display, a storage unit 12 which stores information on a method of acquiring data to be displayed, and information on a display style of display data; The control unit 13 controls the acquisition of display data from the outside and the display of the display data on the display unit 11 in accordance with the storage contents of the storage unit 12. As the display unit 11, even if the power supply is cut off, it is possible to use data that can continue to display data semi-permanently or for some time.

In the display device 10 of FIG. 10, the control unit 13 automatically starts the display device 10 in response to a command given from the outside or the inside, and also acquires display data from the outside and terminates the display. Thereafter, it is also possible to automatically bring the display device 10 into the standby state.

In addition, the display device 10 is displayed on the display unit 11 and the data acquisition unit for acquiring display data for the incomplete acquisition when communication is resumed when communication with the outside is cut off during the acquisition of display data from the outside. It is also possible to further include a rewrite prohibition section for prohibiting rewriting of the data, and a nonvolatile storage section for storing data of one page or more as data that can be displayed by the display section 11.

Embodiments of the present invention will be described below by dividing into several examples. First, as a first embodiment, an information display apparatus, i.e., an information display system which does not have a power supply on the display side but is displayed on the display apparatus side using electric power sent together with data from the wireless terminal side, such as a non-contact IC card, for example. Explain.

7 is a configuration block diagram of the first example of such a display system. In FIG. 7, the system is constituted by a wireless terminal 20 and a wireless indicator 21, and the wireless terminal 20 includes an external wireless transceiver 23, which is external to the wireless transceiver terminal 22. Wireless information can be exchanged. The external wireless transceiver 23 may be a wireless LAN transceiver.

The wireless terminal 20 includes an antenna 27 for near field communication with the power supply unit 25, the control unit 26, and the wireless display unit 21, and a non-contact transmitting and receiving unit 28 for controlling communication using the antenna 27. And a memory unit 29 for storing display data to be sent to the wireless display 21 side, a display unit driver circuit 30 for controlling data display on the wireless terminal 20 side, a display unit 31 and a speaker 32. have.

The wireless display unit 21 includes an antenna 36 for short-range communication with the wireless terminal 20 side, a transmitting / receiving unit 37 for performing the communication, a control unit 35 for controlling the whole, display data, and control data. Mechanical attachment mechanism for mechanically detaching the wireless indicator 21 to the memory unit 38 for storing, the display unit driver circuit 39 for displaying data, the memory display unit 40 and the wireless terminal 20 ( 41).

In general, a small display is attached to the wireless terminal 20, for example, a cellular phone. In order to enlarge the screen display or to display in full screen as a whole, the wireless indicator 21 as a non-power display card is used, and the mechanical attachment mechanism 41 as a mechanical detachment part for attaching the wireless indicator 21 to the cellular phone is provided. Equipped to enable integration. At this time, a transmitting / receiving unit 37 for short-range communication is provided near the mechanical attachment mechanism 41, and the short-range communication system functions to supply power for display on the wireless display 21 side at the same time as communication of display data. Have For example, a short range wireless communication function such as an IC card or a radio frequency (RF) tag can be used.

As the memory display unit 40, for example, a cholesteric liquid crystal which is maintained semi-permanently even when the power supply is turned off, for example, a cholesteric liquid crystal, which will be described later, may also be used. Alternatively, a general buffer memory and a display portion thereof can be used.

FIG. 8 is a block diagram showing a second example of the information display system according to the first embodiment. FIG. In Fig. 8, image data sent from the digital camera 43 is displayed on the wireless display 21 side. That is, the image 44 is photographed by the imager 45, and the image 44 is controlled by the back indicator driving circuit 47 by the back indicator 46 on the rear surface of the digital camera 43. At the same time, the data is sent to the wireless indicator 21 side via the antenna 27.

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, i.e., mobile phone, i.e., display A is transmitted to the wireless display 21 side, for example, with the display 21 mechanically attached to the mobile phone 20. Even if the wireless display 21 is removed from the cellular phone 20, the display is performed as it is.

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

11 is an explanatory diagram of a screen selection transmission mode in the system of FIG. 7. First, on the wireless terminal 20 side, the screen A to be sent to the wireless display 21 side is selected, and the data of the selected screen A is transmitted to the wireless display 21 side by pressing the transmit button. Before data is transmitted, transmission is possible, display transmission during transmission, and display termination is displayed on the display when transmission ends.

12 is an explanatory diagram of data display from various terminals including a digital camera to a non-power display card, that is, a wireless display. Not only the digital camera but also the display data of the cellular phone or PDA can be displayed on the non-powered display card. For example, the cellular phone may display data received from the wireless base station or data acquired via the Internet as shown in FIG. 7 on the non-power display card.

Fig. 13 is an explanatory diagram of a mechanical attachment mechanism 41 as a mechanical detachment portion between a wireless terminal 20, for example, a portable terminal and a wireless display, i.e., a non-powered display card. In FIG. 13, the leaf spring 50 is fixed on the wireless display 21, and the part can be inserted into the insertion part of the portable terminal side, and can be fixed to the wireless display 21. As shown in FIG. The leaf spring 50 may be fixed to the insertion part side of the portable terminal, and a mechanical reinforcement plate may be installed on the wireless display 21 side. The joint is not in electrical contact, but there is no problem even if it is somewhat damaged by friction or the like. Near the attachment portion, for example, an electromagnetic coil 51 corresponding to the antenna 27 for short-range communication described in FIG. 7 can be provided.

FIG. 14 uses springs 52 and 53 in place of the leaf spring 50 of FIG. 13, and mechanical attachment is achieved by inserting a wireless indicator 21 between the springs.

15 and 16 are explanatory views of the mechanical attaching portion of the wireless display 21, i.e., the no-power display card. Two attachment portions 54 are provided on the card so that the display card can be attached vertically or horizontally. In FIG. 15, the display state when the display card is vertically attached is shown. In the vicinity of the two attachment portions, for example, a coil corresponding to the antenna 36 of FIG. 7 is provided, and a driver 55 for displaying and an IC 56 for control are provided on the card. FIG. 16 shows a display state when the wireless display 21, i.e., the non-power display card is attached horizontally.

17 and 18 are examples of mechanical attachment mechanisms different from FIGS. 13 to 16. Here, a magnetic magic tape 57 is used as the attachment mechanism, and FIG. 17 shows a state where the non-power display card is attached to the wireless terminal (portable terminal) 20. FIG. 18 shows a state where the non-power display card is detached from the wireless terminal 20, and a magnetic magic tape 57 is used in place of the attaching portion 54 of FIG.

19 is an example of a wearable display system for attaching the wireless indicator 21 to, for example, a suit or the like. It is necessary to attach the magic tape 58 to the back of the wireless display 21, i.e., the non-power display card, or to attach the display card itself to the arm so that the wireless terminal 20 is close to the display card. At this point in time, the screen can be displayed on the display card attached to the human body.

For example, by attaching a display card to the arm, listening to voice with the mobile phone close to the ear, and bringing the arm close to the mobile phone, it is also possible to conduct a conversation while viewing the screen display on the card. In this case, since the display is a large screen and is a non-powered card, there is an advantage that a battery is not necessary, and it is light and does not increase in volume. For example, when the display card is placed close to the chest with the mobile phone in the pocket of the chest, the display card is detected and data can be transmitted to allow screen display.

Here, it is preferable that the screen display on the wireless display 21, i.e., the non-power display card side, display a still image. The reason for this is that, for example, a device whose display is continued even when the power supply is turned off is generally slow in recording speed. However, since the large screen display itself has a large amount of information, it is often used as a still image. This is because a lot of power consumption is required. Moreover, in general, it is preferable to intermittently transmit the display to the non-power supply display card in order to reduce the power consumption. For example, if the data is transmitted and displayed for 50 ms and the transmission is stopped for 100 seconds, the display power can be significantly reduced.

In the meantime, the display means of claim 1 of the present invention is the memory display unit 40 of FIG. 7, the near field communication unit is an antenna 36, a transceiver unit 37, and a display control unit is a control unit 35 and a display unit driving circuit. Corresponds to 39, and the storage means corresponds to the memory unit 29, and the communication means corresponds to the antenna 27 and the non-contact transmitting and receiving unit 28.

The telecommunication means of claim 2 corresponds to the external radio transceiver 23. The mechanical desorption means in claim 3 corresponds to the mechanical attachment mechanism 41, the display means in claim 4 corresponds to the display portion 31, and the mechanical desorption means is attached to the attachment portion 50 in FIG. 13, for example. It is considerable.

As described above, according to the first embodiment, the large screen display of a non-powered power source, which is usually separated from the mobile device, is generally hands-free by attaching it integrally to a mobile terminal or a mobile device such as a digital camera. It is possible to make a large screen, and to separate after use, and to use the display result of the large screen where the display remains by using the memory function.

In particular, by using a cholesteric liquid crystal display element, a color memory display can be obtained with a high definition of a passive drive type which 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 color display and large screen which are difficult to realize with a mobile printer can be realized. Particularly in a terminal requiring miniaturization such as a mobile phone, the substantial effect of the large screen display is very large.

In addition, by using the wireless communication function of the portable terminal, information of a material or a catalog can be obtained via the Internet and left as a display record on a large screen. When the indicator with the memory display function is put in a bag or a pocket, a large screen can be easily displayed. In addition, by attaching the non-power display card to the human body, it is possible to solve the problem of weight, volume increase, or trouble of charging, which is a drawback of the wearable display using a conventional battery or the like.

Next, as Example 2 in embodiment of this invention, the cholesteric liquid crystal display element as a typical display medium in which display continues in the state in which power supply was cut off, and the display apparatus using the display element are demonstrated.

First, the properties of the cholesteric liquid crystal will be described generally. A cholesteric liquid crystal selectively reflects light in a certain wavelength range, and a chiral nematic liquid crystal as its kind is a liquid crystal in which a cholesteric phase is formed by adding a chiral material (chiral material) to the nematic liquid crystal. The cholesteric liquid crystal can obtain two stable states, a planar state as a reflection state and a focal conic state as a transmission state by electrical control, and the planar state and the focal conic state are semipermanent unless any external force is applied. It has memory maintained as.

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

λ = n × p

The reflection band Δλ increases with an increase in the refractive index anisotropy Δn of the liquid crystal.

21 illustrates a focal conic state. In this state, most of the incident light passes through and becomes transparent. Therefore, when a layer of arbitrary color is formed under the liquid crystal layer, the color can be displayed in the focal conic state. Thus, for example, the wavelength band of the reflected light in the planar state is set to around 550 nm, and a light absorption layer (black) is formed under the liquid crystal layer, whereby a green monochromatic display can be performed on the background black.

22 is an example of a reflection spectrum of a cholesteric liquid crystal. By using plural kinds of liquid crystal elements (blue, green, red) having different reflection bands, full color display is also possible in principle. Also, the reflectance is theoretically close to 50% because it is a reflection of either circularly polarized light on either side.

23 and 24 are explanatory diagrams of general driving waveforms for the cholesteric liquid crystal. The cholesteric liquid crystal is driven by the application of a pulse voltage. When a strong electric field is applied, the helical structure of the liquid crystal molecules is released, and all molecules are in a homeotropic state along the direction of the electric field.

In FIG. 23, for example, a pulse of ± 40 V is applied to remove the electric field, thereby forming a spiral structure in which the spiral axis of the liquid crystal molecules is perpendicular to the electrode, thereby forming a planar state that selectively reflects light according to the spiral pitch.

In FIG. 24, for example, when the electric field is removed after applying a pulse of ± 24 V, i.e., when the electric field is removed after applying a weak electric field such that the spiral axis of the liquid crystal molecules is not completely released, the spiral axis of the liquid crystal becomes parallel to the electrode. A focal conic state that transmits incident light can be obtained. On the other hand, if the electric field of medium intensity is removed and then the electric field is removed, a state in which the planar state and the focal conic state are mixed can be obtained, thereby enabling the display of the halftone.

25 summarizes the response characteristics of the cholesteric liquid crystal. In FIG. 25, V _F0 is a threshold voltage at which the transition to the focal conic state starts, V _F100a to V _F100b is a voltage range in which the transition to the full focal conic state is started, V _P0 is a threshold voltage at which the transition to the planar state starts, V _P100 is a threshold voltage that is fully planar. When the initial state is the planar state, the pulse voltage is raised to a driving band in a focal conic state to a certain range, and when the pulse voltage is increased, the driving band is in the planar state again. When the initial state is the focal conic state, the driving band for the planar state gradually increases as the pulse voltage is increased.

Fig. 26 is a structural example of a reflection type liquid crystal display element using a cholesteric liquid crystal. In FIG. 26, an indium tin oxide (ITO) electrode 61, a display layer 62, and a light absorption layer 63 are inserted inside the substrate 60, and the display layer 62, that is, the liquid crystal layer, is formed of a sealing material ( 64, both ends thereof are sealed.

It is explanatory drawing which shows the example of segment display using a cholesteric liquid crystal. For example, in the display of the last digit "3", the parts of (2) and (5) are in the focal conic state, and the parts of the other (1), (3), (4), (6) and (7) are planners. The display is made by driving in the state.

The structure of the display element using a cholesteric liquid crystal is demonstrated. The cholesteric liquid crystal shows a monochromatic display of the color tone which is basically present, and when two liquid crystals are mixed, they are easily mixed and cannot reflect the desired color tone. That is, when two or more liquid crystals are mixed, the color becomes neutral or non-reflective. Therefore, it is necessary to provide a partition in a pair of opposing matrix substrates, and to form a separation structure in which a plurality of liquid crystals are not mixed in units of adjacent pixels or dots, and each liquid crystal needs to be injected from another injection hole.

As a method of separating the liquid crystal, a capsule structure that traps the liquid crystal in the capsule is also used. However, due to the influence of the interface of the capsule and the thickness of the capsule, a decrease in contrast caused by noise light and an increase in driving voltage are not preferable as a display device. . In addition, since it is difficult to arrange a desired capsule in a desired pixel, in Embodiment 2, a high contrast and a low cost can be realized by adopting a separation structure by partition walls.

28 shows a liquid crystal separation structure in the matrix substrate. The present invention can be applied to both passive simple matrix substrates and active matrix substrates such as TFTs. Example 2 shows an example of a separation structure for inserting two liquid crystals as an example in a passive simple matrix substrate. In order to insert two liquid crystals into adjacent dots, the partition 62 is formed for every line of the electrode 61 of the lower board | substrate 60 side. The upper counter substrate 60 has orthogonal electrode lines and matrix driving is realized. The partition wall 62 is a resin which is not soluble in 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 depressurizing the inside of the cell. However, it is preferable to improve durability by providing adhesion to the barrier material and strongly fixing the counter substrate. The partition material is resin, and adhesion with the counter substrate is possible by pressure and heat treatment.

29 shows a separation of the two liquid crystals 63 and 64. Two injection ports are provided so as not to mix each liquid crystal. The method of injecting the liquid crystal is generally immersed in the liquid crystal storage container in a vacuum, and returned to atmospheric pressure to complete the injection. Therefore, the two injection holes need to be formed at the other end of the cell where the liquid crystal is empty. In order of injection, after inject | pouring one liquid crystal, it seals with the sealing material 65, and injects another liquid crystal. As shown in the figure, it is possible to insert different liquid crystals for each adjacent electrode line. By driving predetermined lines, it becomes possible to display multi-color displays and additive mixed colors.

FIG. 30 shows a pixel configuration in the case where two liquid crystals 63 and 64 in FIG. 29 are used. Since display of white and black is required as a display element, two liquid crystals have a complementary color relationship so that they become white by additive mixing. For example, it becomes white by making orange and blue into the reflected light of a cholesteric liquid crystal. In Fig. 30, a pixel (pixel) 67 is formed of two dots 66 (subpixels) of orange and blue colors. Although the reflected light of the cholesteric liquid crystal has an intermediate reflectance by adjusting the applied voltage, gray scale display is possible, but a stable driving type is binary display (reflectance max and min). If it is binary display, the contrast by the difference of the thickness of a liquid crystal, and the precision of the driving conditions of two liquid crystals can be alleviated. On the other hand, the division in the horizontal direction corresponding to the division of the pixels 67 of the liquid crystal corresponds to the unit of driving by the line of the electrode 61 on the upper substrate 60 side in FIG.

Thus, as shown in FIG. 31, the dot is further divided to form the sub dot 68. FIG. By driving the sub dots individually, gradation display becomes possible. In FIG. 30, four colors of white, black, orange, and blue were used. In FIG. 31, nine colors can be displayed.

In addition, in FIG. 30, FIG. 31, drive display can be carried out using the minimum unit which can drive each dot or sub dot as a virtual pixel unit. If nothing is processed, a high-definition image is formed, but depending on the image, one color dot is continuous and an orange or blue color unevenness is formed. Therefore, when displaying an image, it is possible to display a high-definition black-and-white image by performing image processing so that the number of two colors to light may be about the same in a certain area, for example, several square mm. For example, when the orange color is continuous, the vicinity of the orange dot is converted into the display of the blue dot. By this method, dots can be reported as virtual pixels and converted into high definition display mode in black and white display mode.

32 shows an embodiment when three liquid crystals 69, 70, and 71 are used. This is an example of inserting a cholesteric liquid crystal showing reflection of three primary colors, R, G, and B colors. Although it is difficult to separate and insert three kinds of liquid crystals into one flat substrate, two liquid crystals (Z) 69 different from one liquid crystal (Y) 70 in order to realize the dot arrangement shown in FIG. ) And the line structure of the dot arrangement which has the period of X, Y, Z, Z, Y, X injected alternately between liquid crystal (X) 71, and inserting three types of liquid crystals into a 1-plane board | substrate I found it possible. In the dot array, two types of one pixel in RGB and one pixel in BGR are alternately arranged. G color has high resolution of human perception, and only G-color dots are arranged at equal intervals. Since R and B colors have low perceptual resolution, problems are small even if they are not arranged at equal intervals. Inlets are placed at different ends to prevent mixing.

33 and 34 show an example in which the sub-dots 68 are formed by further dividing the dots to realize gradation display at high resolution. Assuming that binary display is performed in the same manner as in Fig. 30, eight color display in Fig. 33 and 64 color display in Fig. 34 are possible. 33 and 34, when driving display of the minimum unit for driving each dot or sub dot is a virtual pixel unit, high-definition images are formed as in FIGS. It is also possible to switch to the high definition display mode of the monochrome image by the image processing.

Next, the display apparatus which combined the display element using a cholesteric liquid crystal and the printing medium using a paper and a photograph is demonstrated. As described above, the cholesteric liquid crystal has two stable states, a planar state as a selective reflection state and a focal conic state that is substantially transparent. Generally, the light absorption layer (black layer) is provided under a liquid crystal element, and the bright display of a reflection state and the dark display of a transmissive state are performed.

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

For example, a menu display of a restaurant or the like has been proposed as an example of application of electronic paper capable of reflecting display, but it is not necessary to vary the display of the entire area of the menu. For example, although a commodity image may be a fixed display generally, it is preferable to use a photograph in order to improve image quality. It is preferable to use a variable display for the price that is to be displayed together or the special menu guide of the day. Therefore, in Example 2, a display form using a photographic paper or the like as a printing medium and a display element using an electronic paper medium such as cholesteric liquid crystal are combined with each other to realize a superimposed display format. The merchandise image is high in reality as a printed matter, and the price and the special offer can be easily changed in content by using an electronic paper, and the paper and the electronic paper can be fused.

For example, by making the electronic paper using the cholesteric liquid crystal into a matrix display type, it is possible to realize proper display in accordance with the display content on the printed matter. The printed matter is templated to allow for more application forms. For example, by using a calendar as a printed matter, a variable schedule table is realized using the display of electronic paper superimposed on the calendar.

35 shows an example of superimposed display of a variable display element using a fixed-printed printed matter (photograph) and a cholesteric liquid crystal. The variable display element 75 overlaps the surface of the printed matter 74. This variable display element does not form a light absorption layer. 36 shows a display state. In the display element 75 on the printed matter 74, the transmission mode (focal conic state) (left) and the reflection mode (planar state) (right) are shown. When the incident light 77 which is illumination light is irradiated to the display element, it is illuminated on the printed matter as it is in the transmissive mode (left), and the reflected light 78 according to the image of the printed matter is reflected and visually recognized as it passes through the display element in the transmissive mode. That is, the printed matter is visually recognized as it is. In the reflection mode (right), light of 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 onto the printed matter. Reflected light according to the image of the printed matter is reflected to pass 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 matter overlap to form the display light 80. The fusion of printed matter of a paper medium with good image quality and display elements of a variable display medium can be achieved.

The liquid crystal exhibits a color according to the layer pitch. Therefore, depending on the color of the lower printed matter, it may be difficult to visually recognize, and consideration should be given to the area of the printed matter with variable display. This area of the printed matter is preferably black for the highest contrast and the highest visibility. Or, when gray with low reflectance is used, it becomes possible to improve visibility. Moreover, by coloring this area | region and making the reflected light 78 into a specific color, it becomes the additive mixing color with the display element reflected light 79, and it is possible to change a color. For example, the display color becomes white by setting the reflected light 79 of the display element to orange and making the printed matter blue. With various designs of prints, it is possible to change the color of each area. White is the most requested display color. In order to realize white display, it is possible to realize by setting the color of the printed matter and the color of the reflected light of the display element in a complementary color relationship. Orange and blue are complementary colors.

37 shows an example for the purpose of selling a product such as a menu or a catalog. As a product image, the printed matter excellent in display quality is used. For example, in a restaurant, an image that looks delicious is printed and set as a fixed display. Other display, mainly character display, is made into a variable display element. The printed matter portion of the lower layer portion of the variable display element 75 is a printing pattern such as black that improves visibility. As the character display, various displays such as price, special menu, designation of a lunch menu, guidance of business hours, and advertisement can be assumed. By varying the display of the variable display element online, various applications can be considered. For example, custom-made menus are provided on the spot, such as time-based pricing, inventory adjustments, special menu changes, customized advertisement displays, group discounts, women's discounts, family discounts, membership discounts, and point discounts. can do. It is also possible to enlarge the display for the elderly on the spot. As a product image, the image of which reality is good is displayed.

The example shown in FIG. 38 is an example of the restaurant menu. At the bottom of the image, a variable display area is set to display a price. 38 is an exploded view of a printing unit and a variable display unit. When the image is changed due to the replacement of a product, only the printed matter may be changed. The printed matter is easily detachable. Since the variable display element is a matrix type display element, the variable display element can easily cope with a layout change of a printed matter.

FIG. 39 shows an example in which the printed matter of FIGS. 37 and 38 is replaced with a schedule table. The printed matter is a calendar. The schedule is written online on the variable display element. If online, schedule changes can be entered at any time, and multiple schedules can be viewed. Even if there is a change in schedule, it is possible to reflect it immediately. Sharing is also enabled, enabling information sharing to achieve effective management. When the month changes, the printed matter is removed and replaced to become a new schedule. It is also possible to attach and detach the paper by hand and write it on the printed matter. Since the variable display element is a matrix display element similarly to Figs. 35 to 38, it is possible to easily change the layout according to the printed matter. The printed matter is printed in consideration of the display area. The schedule display unit is designed to be visually recognizable such as black, gray, or complementary colors.

40 shows an application example used for map display. The structure is the same as in FIG. The printed matter is a layout diagram of a road map, a venue guide map, a building plan, and the like, and the variable display unit may display a current location, a destination indication, a passing history, and the like. It is also possible to display advertisements tailored to the destination. It is also possible to display the estimated time of passage only online. When the destination is greatly changed, the printed matter is detached and a map of the new printed matter is set. Using this display device becomes a very convenient guide board. In FIG. 40, an example of venue guidance such as an event is shown. Printouts can be customized and distributed according to customers. Equipped with a wireless display system, it is possible to display the current position as it passes through each gate. It is also possible to display useful information near where you are.

41 is an example corresponding to the reference book and the collection of problems. Print the problem on the printed page and display the solution and commentary from behind. It is easy to understand because you can read answers and commentary on the spot. In the case of changing the problem, the printed matter can be removed and replaced. 41 is an example of a collection of problems. Unlike a monitor display of a personal computer, a reflective display device has less fatigue and can be understood efficiently even after studying for a long time.

42 shows an example in which the display for simulation is used in a financial institution such as a bank or insurance. Printed items are printed with common items, and the customer's order numbers are displayed online. Since the simulation results can be obtained on the spot, it can be easily explained. In the case of changing a product, a printed matter can be removed and replaced. 42 is an example of a loan simulation of a bank. If you are an explanation for life insurance, you may come to a customer with a laptop personal computer. Although the display of the personal computer may be explained to the guest, it is very difficult to perceive visually and it is difficult to convince the customer. By using the display device of the second embodiment, the visibility is good, and the guest can easily understand the explanation.

As described above, according to the second embodiment, multi-coloration can be realized by injecting a plurality of colors of liquid crystal in a matrix display element or the like using cholesteric liquid crystal. Compared with the laminated structure, cost reduction is realized by using an interface having few interfaces and high contrast, and using a simplified member.

In addition, by using the cholesteric liquid crystal matrix display element as a variable display element and combining it with a printed matter as a fixed display element, the fusion of electronic paper and paper can be achieved, and the characteristics of the electronic paper and the paper can be extracted to the maximum. . The printed matter can be templated to be detached from the variable display element, and the contents of the template can be changed and developed into various application forms. By making the template of the printed matter into a database, it is possible to immediately change the layout, change the contents, and update the display element. The variable display element can be used many times and the cost is low. The fixed display element may be made by hand instead of printed matter, and it is also possible to superimpose the cholesteric display element on the drawing drawn on the wall of a building.

Next, Example 3 will be described. In the present embodiment, for example, when the non-powered display card as in Example 1 is used to realize semi-permanent data display, for example, the amount of power supplied from the non-contact IC card reader / writer or the like is small. It is necessary to use various control methods. The control of such a power supply circuit will be described as the third embodiment.

As described with reference to FIGS. 23 and 24, two types of voltage values are required for driving the cholesteric liquid crystal, corresponding to the planar state and the focal conic state, respectively. In addition, the voltage of the planar driving is considerably higher than other display elements at about 40V. For example, using a general DC-DC converter requires a capacitor having a large capacitance of μF order, and it is very difficult to make the power supply circuit within a thickness of about 1 mm, that is, within the thickness of a non-power display card.

Therefore, in the third embodiment, a high voltage of about 40 V is generated in an ultra-thin circuit by using a high frequency magnetic field used for supplying signals and power in a contactless IC card or RF tag without using a DC-DC converter. Use the power supply circuit.

43 is an example of such a power supply circuit. This power supply circuit serves as a power supply for display, for example, a logic power supply for a liquid crystal driver and a device itself, i.e., a power supply for display for a cholesteric liquid crystal.

In Fig. 43, for example, an intermediate tap T is provided in a coil having an inductance L whose voltage is induced by a high frequency magnetic field from the non-contact IC card side, and one end of the coil is grounded, so that the intermediate tap T is grounded. Resonant capacitor C1 is connected to the circuit, the logic voltage is supplied through the half-wave rectifier circuit, and is displayed by half-wave rectification without connecting the resonant capacitor between the other end of the coil and the intermediate tap T. Supply voltage is supplied. In this way, by connecting the resonant capacitor only between the intermediate tap from which the logic voltage is pulled out and the ground, the influence of manufacturing fluctuation can be reduced and stable DC power can be supplied.

FIG. 44 is a logic and display power source provided independently in FIG. 43 instead of the intermediate tab. In the drawing, the above circuit is a logic power supply circuit, and it can be considered that the lower part of FIG. In a typical non-contact IC card, the value of L1 for power supply is, for example, about 1.4 μH, and 5 V can be obtained as a voltage for logic by using, for example, 100 pF as C1. With a DC-DC converter, this voltage can be boosted to obtain the display supply voltage, but for that, a capacitor of μF order is required. Therefore, it is assumed that, for example, the display power supply voltage is set to about L2 = 4 to 5 muH.

Subsequently, in the passive matrix driving circuit, it is necessary to apply a voltage corresponding to the planar and focalconic driving to the liquid crystal cell on the scan line at the selection level, and to the liquid crystal cell on the scan line at the non-selection level at the level of the segment line. Regardless, it is necessary to apply a voltage that does not change the state recorded at the time of selection. That is, in general, it is necessary to apply a voltage for suppressing crosstalk. For example, commercially available STN liquid crystal driver LSI requires five voltage values.

45 is a structural example of a power supply circuit corresponding to such a case. The logic power supply circuit is the same as that in Fig. 44, but instead of the power supply circuit shown in Fig. 44 as the display power supply circuit, a circuit in which a power supply circuit using double voltage rectification is connected in series in multiple stages is used. In this multi-stage connection circuit, five kinds of voltages can be supplied, for example, by subtracting the voltage at an appropriate location in accordance with the required voltage value. It is also possible to use a half-wave rectifier circuit and a full-wave rectifier circuit as this rectifier circuit. On the other hand, when overvoltage prevention is necessary in the circuits of Figs. 43 to 45, the reliability of the power supply can be improved by inserting a zener diode between the output terminal and the ground in parallel. In FIG. 45, L2 and L4 are wound in the same direction among the four coils on the display power supply side, while L3 and L5 are wound in the opposite direction to the direction. As a result of the experiment, it was found that generation of a high voltage is possible by using a coil having a different winding method.

Subsequently, in the case of using a non-contact IC card as a non-power display card, for example, the amount of power supplied from the non-contact IC card reader / writer is greatly changed depending on the model of the reader / writer, the distance between the reader / writer and the card, and the like. For this reason, if the display portion on the card continues to operate, the communication distance may be considerably reduced or operation may become unstable due to lack of power during communication, as compared with a normal non-contact IC card having no display portion. Therefore, in the third embodiment, the display function is limited in accordance with the power supply in response to such a case.

46 is an example of the configuration of a circuit which cuts off the entire power supply to the display unit in accordance with, for example, the value of the display power input voltage corresponding to the amount of power supplied from the reader / writer side. 46, the voltage from VR1 which divided 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, and the display power output is supplied when the output of CMP1 is H, but the display power output is output when the output of CMP1 is low level (L). It will be cut off entirely. By setting the reference voltage appropriately, when the power supply amount, that is, the display power supply input voltage is an extreme value close to the required value while the non-contact IC card chip operates, the power supply to the display unit is cut off entirely by using this circuit. .

Fig. 47 is an example of the configuration of a clock output circuit for extending the drive cycle of the display section on average, in accordance with, for example, the amount of power supplied to the contactless IC card. This circuit performs a clock cycle in accordance with the power supply when the power supply is sufficiently larger than the minimum required by the contactless IC card chip, i.e., required for operation, but smaller than the average required during operation of the display unit in a steady state. It extends on average and slows the drive cycle of the display unit.

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 the gate AND1 is stopped. 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 restored, so that the clock is output again. By repeating this operation, the clock cycle, that is, the driving cycle of the display unit, is slowed down on average.

48 is a structural example of an output circuit of an image display prohibition signal for displaying only text data on a display unit and not displaying image data in accordance with the power supply amount. This circuit has a display function by displaying only text data on the display unit and not displaying image data when the power supply amount is larger than that of the non-contact IC card chip, but is considerably smaller than the average requirement when the display unit is operated in a steady state. Is a circuit that limits In FIG. 48, when the display power supply voltage divided by VR3 is smaller than the reference voltage, the output of CMP3 is H, and the image display prohibition signal is output.

Next, the current limitation of the display power supply will be described. The passive matrix cholesteric liquid crystal display panel can be driven by the existing passive matrix STN liquid crystal driver LSI by using the same power supply circuit as described above. Except during startup, the power consumption is relatively small and can be sufficiently operated with power supplied from a weak contactless IC card reader / writer or the like. However, since the conventional driver LSI is based on moving picture display, the conduction impedance of the transistor in the last stage is low, and a very large instantaneous current (5 to 10 times in normal operation) flows in the transient state at startup. For this reason, there is a possibility that the existing driver LSI cannot be started even if the power is supplied several times during normal operation.

However, preparing a power supply with a large supply capacity only for start-up is not very costly. In addition, it is impossible to supply 5 to 10 times the power in normal operation with the conventional weak output contactless IC card reader / writer. For this reason, in Example 3, in order to stably start the existing driver LSI at the power supply as close to the power consumption at the time of normal operation as possible, the current limit of the display power supply is restricted.

Fig. 49 is a structural example of a current limiting circuit of a display power supply. In FIG. 49, the value of VR1 or the like is set in advance so that a current limit is made when the voltage of the logic power supply is lower than or equal to a predetermined value. For example, when the value of the voltage drop of the logic power supply exceeds 5% of the standard value, it is for display. Current limit to the power supply is made.

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

In the conventional general liquid crystal driver LSI, the display power supply current may greatly exceed the average current during normal operation, depending on the display pattern even when not started. At this time as well, the current is restricted and the driving of the display panel is stopped until the display power supply voltage is restored to a predetermined value, so that the existing driver LSI can be stably operated.

Next, temperature compensation in the drive characteristic of the cholesteric liquid crystal in Example 3 is demonstrated. The cholesteric liquid crystal requires two kinds of drive waveforms having different crest values corresponding to the planar and focal conic states. As such, the crest value changes with temperature. For this reason, in order to expand the operating temperature range, temperature compensation for changing the crest value in accordance with the temperature is required. In Example 3, the peak value of the drive waveform is changed linearly with temperature, thereby ensuring the margin of the peak value over a wide operating temperature range.

Fig. 50 shows examples of crest values in the planar and focal conic drive waveforms of the cholesteric liquid crystal when the pulse width is 10 ms. Since a certain crest value is always a planar state, the crest value corresponding to the planar state is represented by a straight line a of one line corresponding to the lower limit value. On the other hand, since the change to the focal conic state is made only in the voltage range of a certain crest value, the crest value corresponding to the focal conic drive is represented by a straight line (b-b ') of two lines corresponding to the lower limit and the upper limit.

In Fig. 50, since the crest value corresponding to the focal conic state changes greatly with temperature, the margin of the crest value for driving to the focal conic state becomes small regardless of the temperature.

On the other hand, it is known that when the pulse width is widened, the margin of crest values corresponding to focal conic driving increases. 51 shows an example of crest values corresponding to planar and focalconic driving at a pulse width of 50 ms. The crest margin is several times higher than that 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 peak values of two types of drive waveforms in the planar drive and the focal conic drive in the third embodiment are changed linearly within the operating range in accordance with the temperature, respectively. Compared with FIG. 50, three lines are shown between the upper limit and the lower limit of the focal conic state, and the center line shows the upper limit of the crest value corresponding to the lower limit of the operating temperature range, that is, the focal conic state at 0 ° C. And the average of the lower limit and the upper limit of the operating temperature range, that is, the straight line connecting the average of the upper limit and the lower limit of the crest value at 50 ° C.

In Example 3, the peak value of the drive waveform corresponding to the focal conic state is basically changed by the central straight line corresponding to the temperature, but the margin is originally the focal conic in FIG. 50 at each temperature. What is necessary is just to enter between the upper limit and the lower limit corresponding to a state, and a new margin becomes large compared with the margin in FIG. In other words, within the above-described three straight lines corresponding to the focal conic state, the upper straight line shows the maximum crest value in the margin and the lower straight line shows the minimum crest value in the margin. The value in the margin corresponding to the straight line of these three lines becomes 25.4V minimum, 32.6V maximum, and an average of 29.0V at 0 degreeC. At 50 ° C, the minimum is 15.9 V, the maximum is 23.7 V, and the average is 19.8 V.

52, the peak value of the drive waveform in the planar state in Example 3 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 the predetermined value. It can be changed in response to the temperature. The characteristic is shown by the line in the upper side of a planar state in FIG. On the other hand, the value at 0 ° C of this line is 49.3 V, which is 1.7 times the average value of 29.0 V in the line of 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 of voltage peak values of the planar driving and focal conic driving described in FIG. 52. In Fig. 53, the amplification factor of AMP1, that is, the amplifier to which the temperature sensor output is given, is equal to R2 / R1, and the 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 equal to the value of the line showing the average value within the line of 3 lines corresponding to the focal conic drive described in FIG. It is set to lose. In other words, the sensor output value is 29.0 V at 0 ° C and 19.8V at 50 ° C. So 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 straight line for the planar state described in FIG.

TR1 and TR2 form an emitter follower circuit to sufficiently lower the output impedance, and the output of each emitter voltage, the planar voltage and the focalconic voltage, is about 0.7 V below the base voltage of each transistor. Thus, the planar voltage output is about 48.6 V (= 49.3-0.7) at 0 ° C and about 33.0 V (= 33.66-0.7) at 50 ° C, which is the lowest crest of the drive voltage waveform corresponding to the planar state, i. The lowest voltage corresponding to the planar state described, which is sufficiently higher than 43.3 V at 0 ° C. and 30.9 V at 50 ° C.

The base voltage of TR2 is equal to R4 times the output voltage of AMP1 divided by (R3 + R4). The value of this coefficient is equal to 1 / 1.7, and the output value of the emitter voltage of TR2, that is, the focal conic voltage, is 28.3 V (= 29.0-0.7) at 0 ° C and about 19.1 V (= 19.8-0.7) at 50 ° C. to be. These values are represented by the straight lines of the three lines described in Fig. 52, which are sufficiently larger than the minimum voltages (25.4 V and 15.9 V) corresponding to the focal conic states and sufficiently smaller than the maximum voltages (32.6 V and 23.7 V). .

In addition, as described above, the peak value of the driving waveform corresponding to the focal conic state is changed linearly in correspondence to the operating temperature of the liquid crystal cell, thereby ensuring a margin equivalent to a pulse width of 50 ms even with a pulse width of 10 ms. can do. That is, although the display speed is made five times, an equivalent value can be ensured as the margin of crest value, and stable operation is possible in a wide temperature range in a display device using cholesteric liquid crystal.

In the above, as the 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 compensating circuit for a cholesteric liquid crystal drive voltage, and the like have been described. Rather than being used independently of each other, several individuals are used in combination. The combination can be set as a type which selects and combines several circuits as needed.

In addition, the value of the element and the value of the reference voltage in each circuit can be determined relatively easily. Although the temperature compensation circuit of FIG. 53 has been described in detail with regard to the determination of the value of the resistor and the like, the operation of the current limiting circuit described in FIG. 49 is described in a general handbook and the like, for example, and the value of the element can be easily determined.

As described above, according to the third embodiment, it is possible to realize a significant cost reduction and thinning of the power supply circuit for a display panel using cholesteric liquid crystal, for example, and to shorten the communication distance by limiting the display function in response to the amount of power supplied. In addition, operation instability can be avoided, and the existing driver LSI can be stably and quickly started by limiting the current of the display power supply during startup, thereby greatly expanding the range of mobile device applications.

Next, the driving method, the image display method, etc. of the liquid crystal element in the display device using a semi-permanent memory display element, for example, a cholesteric liquid crystal, are demonstrated as Example 4. FIG. In Embodiment 4, for example, in order to use a display device using a cholesteric liquid crystal element as a non-power source, a driving method and an image display method for driving the liquid crystal element or performing image display in a form of low power consumption as long as possible. Explain about.

Fig. 54 is a block diagram showing the configuration of a driver for driving a liquid crystal display element, for example, a matrix type liquid crystal element, according to the fourth embodiment. This driver itself is almost identical in structure to the existing STN common driver on the market, for example. The configuration is not peculiar to the present invention, and the fourth embodiment is characterized by its driving method.

In FIG. 54, power and data sent from the wireless terminal 20 that transmits power and data, an IC card reader / writer, and the like are received by the power / data receiving unit 81 and control signals in response to the reception result. The signal conversion circuit 83 is controlled by the circuit 82 to drive display of the matrix liquid crystal element 84.

The matrix type liquid crystal element 84 generally includes a scan electrode for selecting a line and a signal electrode for giving data, and a polarity inversion signal FR and a line selection signal for alternating a drive signal of the liquid crystal element on the scan electrode side. And an Lp signal for shifting the scan line together with the latch of the data on the signal electrode side. On the signal electrode side, in addition to the FR signal and the Lp signal, data signals and the like used for recording are given.

The scan electrode side is generally given an Eio signal for selecting scan electrodes in order to write data one line at a time from the top line, and here the mode is called a common mode. On the other hand, instead of recording one line from the top, it is also possible to give a signal called a segment mode for selecting a line for recording data on an arbitrary line, and switching for switching between these two modes. A signal is also given.

Fig. 55 is an explanatory diagram of a screen rewriting method according to the fourth embodiment. Conventionally, when the screen is rewritten, the previous display screen is collectively reset, but at this time, at least several tens of mW of power is consumed when the screen is reset, for example, supplied from the IC card reader / writer side in the non-contact IC card. It becomes considerably larger than 5-10 mW which is electric power, and it is difficult to collectively reset on the display apparatus side which does not have a power supply.

Therefore, in the fourth embodiment, power consumption is restrained by resetting the screen by resetting the number of lines, for example, 4 lines, and rewriting the screen repeatedly by the number of lines at the same time. As the data, for example, the recording data itself is used for resetting without using special reset data such that all the pixels are back.

In FIG. 55, the lower half of the screen shows the screen for the previous display, and the upper half shows the screen of the new display. Here, starting from the top line, the recording leading line, that is, the recording lines of each of the above-described lines, is almost on the center of the screen, and the data on this line is written, and at the same time for the reset line, for example, four lines. Reset using the recording data is performed. This operation will be further described with reference to FIG. 56.

In Fig. 56, an operation of first setting four lines as a reset line is performed. When the Eio signal and the Lp signal are simultaneously input in Fig. 56, first the first line from the top of the screen in Fig. 55 is selected, and the data can be written to the line. Subsequently, when the second pulse of the Eio and Lp signals is input together, the first line selected first is shifted by the Lp signal so that the second line is selected and at the same time, the first line by the Eio signal input at the same time. Also selected simultaneously, two lines of the first line and the second line are selected. This operation is repeated, so that in the reset line setting section, the first to fourth lines are selected, and the data can be written to the four lines.

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

At the beginning of the next recording section, the Eio signal and the Lp signal are simultaneously input, and the second to fifth lines selected before are shifted by one line, and the third to sixth lines are selected. At the same time, the first line on the screen, that is, the first line, is also selected by the input of the Eio signal. In this state, by giving data of the first line, data to be originally recorded is recorded on the first line, while data of the first line is given as data for resetting from the third to sixth lines, and the previously displayed data. Is reset. At this time, the second line is a stop line set in the stop line setting section, and data is not recorded.

In response to the input of the next Lp pulse, the previously selected line is shifted so that the second line and the fourth to seventh lines are in a selection state. In this state, the data of the second line is given, the data originally recorded on the second line is recorded, and the previous display data from the fourth to the seventh line is reset.

In addition, by the input of the next Lp pulse, the third line and the fifth line to the eighth line are similarly selected, and data of the third line is recorded. In the third line, the data of the first line is recorded at the input of the two preceding Lp pulses, but in general, the response time of the cholesteric liquid crystal is several tens of ms order, depending on the material properties. At the time of input of the Lp pulse as the timing at which the data of the second line is written, the third line is a stop section, and in this section (for example, 50 ms or less), the pixels of the second line are in the focal conic state or the planar state. The transition state is in the transitional state, and when the data of the third line is actually given, either the focal conic state or the planar state as the actual recording state is determined. This operation is repeated, for example, up to the 240th line, i.e., until the data of the bottom line on the screen is recorded.

Next, another power consumption suppression method in Example 4 will be described with reference to FIG. 57. FIG. 57 is a signal for determining polarity inversion in the drive waveform of the liquid crystal element described with reference to FIG. 54. In general, in cholesteric liquid crystals, it is preferable to invert the polarity of the pulse among the data recording pulses of one line. This is to solve the problem of deterioration of the liquid crystal and deterioration of image quality (image retention, crosstalk, etc.). For example, there is a method of reversing polarity every several lines or every frame. This is not a preferred method.

The upper side of Fig. 57 shows a polarity inversion scheme of a conventional drive signal. For each line, a method in which a polarity inversion is performed by first giving a positive pulse and then a negative pulse is used. The lower waveform in FIG. 57 is the polarity inversion scheme in the fourth embodiment. For example, the polarity of the drive signal is reversed in the form of a positive pulse at the first line and then a negative pulse at the first line, and a negative pulse at the beginning and a positive pulse at the beginning on the second line. By doing so, the polarity in one line is inverted, but since the inversion period itself is doubled, power consumption can be suppressed and no problem is caused in display quality.

58-60 is explanatory drawing of the effect of the drive system demonstrated in FIGS. 55-57. 58 and 59 show the effects of the fourth embodiment corresponding to FIGS. 3 and 4 described as the prior art. By using such a driving scheme as described above, instead of using a long pulse having a period of several tens of ms, for example, even using a short pulse having a period of about 8 ms, no decrease in contrast occurs and a weakness of about 5 mW is achieved. By the driving circuit using electric power, high-quality data recording can be performed on the screen of the QVGA size (320 dots wide x 240 dots vertical).

FIG. 60 is an explanatory diagram of power consumption suppression effect by resetting four lines in FIG. 56 without performing a bulk reset in Example 4; In the case of collective reset, the power consumption at the start of driving becomes extremely large, but in Example 4, such increase in power consumption can be suppressed.

Next, the skip driving method as the image recording method in Example 4 will be described with reference to FIGS. 61 and 62. In this driving method, that is, the skip driving method, it is assumed that data is written to pixels at arbitrary positions on the matrix by applying a signal in the segment mode instead of the common mode described above to the scan electrode side.

In Fig. 61, first, a full reset of the display screen is performed. In this reset, the whole may be simultaneously transitioned to the focal conic state, but since the power consumption increases, a simple reset to an incomplete focal conic state by a pulse having a short period of 3 ms or less has the effect of the reset. Alternatively, the entire display portion may be divided into a plurality of blocks and reset for each block.

Then, on the scanning electrode side, a portion where the same pattern, here a white background pattern, is to be recorded, is selected, and collective writing of the electrodes of that portion is performed. This makes it possible to draw a white background pattern on a plurality of lines at the same time, thereby reducing the driving time.

Although the white background pattern is exemplified here as the same pattern, there is no particular limitation on the same pattern. However, since a pattern with a high spatial frequency such as a checkered pattern consumes more power, there is a limit to the number of lines for batch recording according to the pattern. Needs to be. In other words, the higher the spatial frequency, the smaller the number of lines to be collectively selected.

In image processing, if an image of a random pattern processed by an error diffusion method that diffuses an error for a certain pixel to surrounding pixels is less likely to exist in the same pattern, the noise is applied to the density signal of the grayscale image, and the threshold The same pattern may exist in the systematic deserialization method as a kind of the binarization dithering method, and the halftone image by half-dots. However, this skip driving method is particularly effective when there are many white backgrounds and the like such as text display.

In Fig. 61, after collective recording of the same pattern, normal sequential line driving (passive driving) is performed, and sequential recording of the remaining portions other than the same pattern is performed. At this time, when the interlace scanning is performed, the entire image can be recognized more quickly. This skip driving can be realized by a simple driving circuit without using a complicated method such as MLA driving, and is characterized by varying the number of lines to be collectively driven by a pattern.

Fig. 62 is a flowchart of processing of this skip driving method. 62, the left side is the same pattern detection process flowchart as drive preprocess. In this process, for example, binary screening is performed by an error diffusion method or the like in step S using an 8-bit original image, a scan electrode as a comparison source of data is selected as loop 1 in step S2, and data is compared in step S3. The scan electrode as a target is selected, a pattern comparison of data for each electrode is made in step S4, and it is determined whether or not the same pattern is detected in step S5, and if detected, the same pattern exists in step S6. After the coordinates or address are stored in the address storage memory 86 of the same pattern, and if not detected again, the scanning electrode of the comparison destination is immediately changed in step S3, and processing continues, and scanning as the comparison source selected in step S2 is performed. At the end of the comparison with respect to the data of the electrodes, in step S2 the scan electrode as the comparison source is changed to continue processing. Uh, the process ends after all data has been compared.

62 is a flowchart of driving, that is, of a recording process. When the processing starts in Fig. 62, in step S10, for example, a batch reset processing on the entire surface of the display unit is performed, and in step S11, one identical pattern is extracted from the address storage memory 86 of the same pattern, and the pattern is recorded in step S12. A plurality of scan electrodes to be selected are simultaneously selected, batch data recording is performed in step S13, and the processing of steps S11 to S13 is performed for the next pattern. When the recording of the same pattern is finished, a recording loop for an unrecorded line is executed in step S14, and passive recording of data is performed for each of the remaining portions other than the same pattern recorded in step S15 by one line, thereby completing the display process. .

Next, the multi-value recording method in Example 4 will be described with reference to FIGS. 63 and 64. In general, in a display device using cholesteric liquid crystals, there is a problem that when the recording becomes high speed, the transition to the focal conic state becomes insufficient, so that the entire image is blurred. Can perform multi-value recording, displaying a clear image by repeating it.

First, the case of ternary recording will be described. Initially, the original image is screened at three levels of 0, 128, and 255 in the case of three values, for example, 8-bit 256 gray levels. Although the type of this processing does not need to be particularly limited, a pseudo halftone image having high resolution can be generated by using the above-described error diffusion method, the blue noise mask method as the image processing in a larger area, or the like.

After this ternary screening process, a pixel of black (0) level is extracted, only the extracted pixel, that is, the pixel on which the original black is recorded, is extracted, and an intermediate image is recorded as the first scan only in that pixel. That is, by driving the liquid crystal element at a higher speed than usual, recording of the halftone level image is performed in a state where the output voltage from the driver is fixed. By adjusting the driving speed, it is possible to obtain an image in which halftone data is recorded in a pixel in which original black should be recorded as shown in FIG.

Subsequently, as shown in FIG. 64, the second scan, that is, recording of data obtained by converting the black (0) level and the intermediate (128) level into the black (0) level is performed. It becomes grayscale, and data of intermediate grayscale or white grayscale is recorded in the other part, and a three-dimensional image is finally formed. This makes it possible to easily display the image of the multi-level gradation, and at the same time, the user can grasp the entire image of the display quickly. In other words, a faint image is gradually displayed clearly at first, and multi-value display of three or more values can be realized by recording a plurality of times at an appropriate scanning speed. In contrast to this method, a method of cumulatively recording pixels to be made white to gray scales is also possible.

As described above, according to the fourth embodiment, in a display device that does not have a power supply using a display element having semipermanent memory characteristics such as cholesteric liquid crystal, power consumption during driving can be greatly suppressed, and furthermore, It is possible to perform high quality display in a short time without deterioration.

Next, Example 5 will be described. In the fifth embodiment, a more detailed configuration and a wider range of applications of a semi-permanent memory device such as cholesteric liquid crystal will be described. In Example 5, the automatic display device includes a display medium having semi-permanent memory characteristics for holding display contents even when the power is cut off, information on a method of acquiring data to be displayed, and information on a display form of the acquired display data. And a memory for holding display, at least for example, an Internet connection for acquiring display data according to the data acquisition method, and a control unit for displaying the acquired data according to the retained display style. After being activated in response, the display data is acquired, and the data is displayed on the display medium having the semipermanent memory property with the display mode.

65 shows an example of the configuration of such an automatic display device. In FIG. 65, the automatic display device 90 is, for example, compared with the wireless display 21 shown in FIG. 7, in addition to the control unit 35, the display unit driver circuit 39, and the memory display unit 40. An internet connection unit 92, a battery 93, a timer 94, and a nonvolatile memory 95 are provided.

In FIG. 65, the automatic display device 90 is equipped with a host function and a connection mechanism to the Internet. When the power source 91 is turned on, the operation of the Internet connection unit 92 is performed using a URL stored in the nonvolatile memory 95. By obtaining the page data, the page data is displayed on the memory display unit 40 in accordance with the display mode information stored in the nonvolatile memory 95, and the power is automatically cut. The contents of the nonvolatile memory 95 can be freely rewritten from the outside, for example, from the wireless terminal side. It is also possible to automatically activate the automatic display device 90 by the timer 94 backed up by the battery 93.

In the meantime, the display means in claim 25 corresponds to the memory display portion 40 of FIG. 65, the memory means corresponds to the nonvolatile memory 95, and the control means corresponds to the control portion 35 and the display portion driving circuit 39. . The nonvolatile memory means according to claim 30 is also equivalent to the nonvolatile memory 95. The display data of the memory display portion 40 is also rewritten by storing display data for a plurality of pages in the memory 95. In addition, even if the contents displayed on the memory display unit 40 are erased for any reason, the contents of the memory 95 can be recovered.

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

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 a wireless LAN or Bluetooth, and the automatic display device 90 receives the start command from the communication terminal 97. In response to the operation as shown in FIG. A battery back-up monitor (not shown) always monitors the start command from the communication terminal 97 side, and automatically starts by a start command issued at the time up of a timer (not shown) mounted on the communication terminal 97 side. It may be.

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

When the distance from the communication terminal 97 becomes less than or equal to the predetermined value, the automatic display device 90 is automatically started to perform the operation as shown in FIG. In the non-contact IC card, there are a near type having a short communication distance of about 10 cm but a high communication speed, and a close communication type having a long communication distance of about 1 m. It is also possible to mount both types of IC card chips in the automatic display device 90. In this case, since the power obtained from the communication terminal 97 side becomes small in the state where only the near type can operate, the power supply to the display unit is cut off entirely, and image data is not transmitted due to the limitation of the communication speed. For example, it is realistic to transmit only text data.

69 is an example of the information of the acquisition method of the data to be displayed stored in the volatile memory 95 of FIG. 65, and the display style information of the obtained display data, for example. In Fig. 69, a URL or a path name to a file is stored as an acquisition method of data to be displayed at addresses 0-255. The contents are, for example, URLs of ××××× .com.

After address 256, data relating to a display form is stored, and display form data similar to general print form data is stored, such as specifying the number of pixels, vertical length, or horizontal length of the display screen, designation of equal magnification, enlargement, or reduction.

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

Fig. 71 also displays an update date and time in the display section of the data, which is transmitted from the host (communication terminal) side in the form of additional writing in the display data and displayed. In contrast, in Fig. 70, for example, display data and update date and time information are independently transmitted from the host side. Since the update date and time are displayed, the user can immediately determine what information.

The structural example of the automatic display apparatus in Example 5 is further demonstrated. First, the memory display unit 40 shown in FIG. 65 or the like has an optimal semipermanent memory property such as cholesteric liquid crystal as described above. However, the memory display unit 40 does not have such a property, for example, in units of several hours or one day. It is also possible to combine an element capable of retaining the contents, an element having no memory at all, and a nonvolatile memory.

In this case, it is also possible to have one page or multiple pages of the nonvolatile buffer memory. In the case where the display element has semipermanent memory characteristics, the buffer memory is not necessarily required, but by mounting the buffer memory for one page, part or all of the display contents of the display element are turned off because the memory retention temperature upper limit is exceeded, for example. Even if discarded, the display can be restored immediately. In addition, the display contents can be changed immediately by mounting the buffer memory for plural pages.

Also, the automatic display device may prohibit rewriting of data displayed on the memory display 40 of FIG. 65, for example. The rewrite prohibition method may be hardware, for example, such as the write prohibition method for a flexible disk (floppy disk), but it may be software.

In addition, when the communication with the outside is cut off for some reason during the operation in which the automatic display device is acquiring the display data from the outside, the incomplete data of the display data is not obtained when the communication with the outside is resumed. You may. Such a method is widely used, for example, in download support tools such as freeware. The RESUME function in these support tools is available for acquiring incomplete acquisition data.

In addition, the automatic display device according to the fifth embodiment may include a history storage function relating to a method of acquiring display data. Such a function is not necessary, but having such a function makes it easy to refer to data displayed in the past. Naturally, such a history may be stored in the nonvolatile memory 95 of FIG. 65 or stored externally via the host.

Finally, a wide range of applications of the automatic display device in Example 5 will be described. Briefly explaining such an application example, the mobile terminal screen may be transmitted to the automatic display device as it is, but high definition and large screen data corresponding to the mobile terminal screen may be separately constructed and transmitted to the automatic display device.

In addition, in order to install the automatic display device driver on the mobile terminal from the automatic display device, the automatic display device may be equipped with an installer for the mobile terminal. In general, the mobile terminal can use the memory effectively by installing a driver when necessary and erasing the memory when the amount of memory is small.

In addition, the automatic display device has a shape of a refill corresponding to a replaceable page in the system notebook, and it is also possible to display data on both sides of the refill. In this case, antennas are provided on both sides, and a magnetic shield layer is provided in the middle, and the voltages generated by the two antennas are compared, and the display data of the surface on which the antenna with the high voltage is provided can be rewritten first.

Furthermore, in the automatic display device, only the display portion including the display panel + driver LSI can be detached, and a function of erasing the data of the display panel and the buffer memory can be provided, so that a portion of the display screen is fixed to the advertisement display area. The advertisement data can be downloaded and displayed therein in a predetermined order when the display data is updated.

Such an application example is further demonstrated using drawing. The automatic display device (wireless display sheet and wireless display card) in FIG. 72 is equipped with a non-contact type IC card interface (antenna, IC chip). When the automatic display device is close to a cellular phone, digital camera, or PDA equipped with an IC card reader / writer, the automatic display device requests transmission of screen data. The mobile phone or the like is provided with an automatic display device driver, and the mobile screen data is stored as it is, or high definition and large screen data corresponding to the mobile screen data are constructed and transmitted to the automatic display device. As described above, the automatic display device performs display drive control according to the electric power supplied from the cellular phone, displays screen data on the display panel, and automatically enters the standby state.

We only bring sheet-like thing close to cell-phone and can enlarge map, display whole e-mail or display contents which we want to take note and are very convenient. The automatic display device driver of the cellular phone can also be installed from the automatic display device.

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

The automatic display device may be a refilled shape of the system notebook. In that case, both surfaces may be displayed. By providing the antennas on both sides and providing the magnetic shield layer in the middle, it is possible to identify which display surface side the IC card reader / writer is on. It is preferable to give priority to display data processing on the side where the IC card reader / writer is located.

The automatic display device as the second display for a PC shown 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 transmission of screen data as the second generation or later display. An automatic display device driver is installed in the desktop personal computer, and screen data is transferred to the automatic display device as in a normal display. The automatic display device displays the screen data on the display panel, automatically requests the transmission of the next screen data, and repeats the series of operations.

It is well known that when a plurality of displays are used, work efficiency is improved. Since the automatic display device is thinner and lighter than a normal display, does not occupy a place, can be used in a free layout, and is cheaper than a normal display, four to five sheets may be used simultaneously. This is an essential item to comfortably read deeply nested online manuals.

Next, the automatic display device in this embodiment is equipped with a wireless LAN interface and a battery. The automatic display device is activated when the owner's desktop personal computer is activated and authentication of the owner is completed. Request the transfer of assistant schedule table data to the desktop personal computer. An automatic display device driver is installed in the desktop personal computer to transmit assistant schedule table data. The automatic display device displays an assistant schedule on the display panel, and automatically enters the standby state. In the standby state, only the display portion of the automatic display device can be removed.

Many people print member schedules every day. It consumes about 250 sheets of paper per person per year. By using the automatic display device, it is possible to omit the trouble of printing the member schedule table daily, and at the same time, it is possible 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 is close to a mobile phone equipped with an IC card reader / writer, the automatic display device requests the transmission of newspaper articles. The mobile phone is equipped with an automatic display device driver, which downloads a newspaper article from the homepage of the newspaper company and transmits it to the automatic display device. The automatic display device performs display drive control according to the power supplied from the cellular phone to display newspaper articles on the display panel, and automatically enters the standby state.

We only close sheet-like thing to cell-phone and can read the latest newspaper article and are very convenient. This same technique can also be applied to electronic books. You don't need to download it in advance, so you can start reading books or magazines that stand out from the tank's leather handle ads, for example. Compared to an electronic book which is downloaded in advance to a secure digital (SD) card or the like for copyright protection or the like, it is remarkably convenient and comfortable.

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 started. Requires the transmission of newspaper articles to the desktop personal computer. An automatic display device driver is installed in the desktop personal computer, and the newspaper article is downloaded from the homepage of the newspaper company and transferred to the automatic display device. The automatic display device displays newspaper articles according to the sizes of the display panels (left and right sides of A6 to A3 plates), and automatically enters a standby state. In the standby state, only the display portion of the automatic display device can be removed.

By using the automatic display device, since printing, delivery, and delivery to each household are unnecessary, the subscription fee is cheaper than that of a conventional newspaper, and much newer articles can be read than a conventional newspaper. The paper consumption and paper dust generation amount can also be reduced.

A large number of automatic display devices shown in FIG. 74 are attached to a tram vehicle, and each includes a Bluetooth interface and a battery. In response to a startup command from a Bluetooth-equipped notebook personal computer carried in the vehicle, one of the automatic display devices identifies and starts the command by the IC and requests transmission of advertisement data. An automatic display device driver is installed in the notebook personal computer, and the advertisement data to be displayed on the activated automatic display device is transmitted. The automatic display device displays an advertisement on the display panel and automatically enters a standby state. A series of operations are repeated until the display contents update of all automatic display devices is completed.

By using the automatic display device, printing costs, attachment costs, paper consumption, and paper dust generation amount can be reduced. A personal computer can be permanently installed in a vehicle, and the advertisement content can be changed entirely according to the time zone and the running area of a train. The same technique can also be applied to price indicators such as supermarkets.

Subsequently, many automatic display devices used for building wall advertisements are attached to the wall of the building, and each has a Bluetooth interface and a battery. A Bluetooth-equipped personal computer is installed in a building and is connected to an antenna provided in a plurality of parts on a wall surface. In response to a startup command from the personal computer, one of the automatic display devices is started to request transmission of advertisement data. The notebook personal computer is provided with an automatic display device driver, and transmits advertisement data to be displayed on the automatic display device being activated. The automatic display device displays an advertisement on the display panel and automatically enters a standby state. A series of operations are repeated until the display contents update of all automatic display devices is completed. In the case of displaying a large screen with a plurality of automatic display devices, since one by one requires only image data of each part in charge, the image cutting process is easy.

By using an automatic display device, printing cost and attachment cost can be reduced. Depending on the time of day, it is also possible to completely change the content of the advertisement. This same technique can also be applied to a station timetable.

A large number of automatic display devices used as conference distribution materials shown in FIG. 75 are provided in a conference room, and each includes a Bluetooth interface and a battery. In response to a startup command from a Bluetooth-equipped notebook personal computer taken into the conference room, one of the automatic display devices starts up and requests transmission of conference data. The notebook personal computer is equipped with an automatic display device driver, and transmits conference data to be displayed on the automatic display device being activated. The automatic display device displays the conference data on the display panel and automatically enters the 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 amount, and paper dust generation amount can be reduced. Materials needed quickly during meetings can be distributed quickly. In addition, since confidential data can erase data in the display panel and the buffer memory at the end of the meeting, security can be increased by using an automatic display device.

Next, the example used for the mobile display with an advertisement display function is demonstrated. Similar to the enlarged screen display of the mobile device (FIG. 72), except that a part of the display screen is a fixed advertisement display area. At the time of updating the display data, the advertisement data is downloaded from a predetermined URL and displayed in the advertisement display area. Effective as a sales promotion tool, companies are more likely to distribute large quantities of autonomous displays for free.

As described above, according to the fifth embodiment, the latest information can be displayed by starting an automatic display device without operating a personal computer or the like, for example, by bringing a contactless IC card close to an IC card reader / writer built in a personal computer or PDA. It is possible to realize an automatic display device using a convenient electronic paper that is highly fused with the feature that the display does not turn off even when the power supply is turned off, and the feature that the display content can be arbitrarily rewritten.

The present invention is natural in the manufacturing industry of mobile devices including IC cards, electronic papers, liquid crystal display elements, portable terminals and digital cameras, and can be used in all industries using these display devices, display elements, and mobile devices.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of the prior art example of a cholesteric liquid crystal element.

2 is a diagram showing a conventional example of a drive waveform for a passive matrix element.

3 is a diagram showing a problem of the conventional example of the cholesteric liquid crystal drive system (part 1).

Fig. 4 is a diagram showing a problem of the conventional example of the cholesteric liquid crystal drive method (part 2).

5 is a principle block diagram of the information display system of the present invention.

6 is a principle block diagram of the display device of the present invention.

7 is a block diagram showing the configuration of a first example of a display system according to the first embodiment.

8 is a block diagram showing the configuration of a second example of the display system according to the first embodiment.

9 is an explanatory diagram of the same screen display mode in the system of FIG. 7.

10 is an explanatory diagram of a two-screen display mode in the system of FIG. 7.

11 is an explanatory diagram of a screen selection transmission mode in the system of FIG. 7.

12 is an explanatory diagram of data display on a wireless display.

It is explanatory drawing of the mechanical attachment mechanism (part 1) of the portable terminal side.

It is explanatory drawing of the mechanical attachment mechanism (part 2) on the portable terminal side.

15 is an explanatory diagram of a mechanical attachment part (part 1) on the radio indicator side.

16 is an explanatory diagram of a mechanical attachment part (part 2) on the radio indicator side.

It is explanatory drawing of the magnet magic tape as an attachment mechanism of a terminal side.

It is explanatory drawing of the magnet magic tape as an attachment mechanism by the side of a radio display.

19 is a diagram illustrating an example of a wearable display system using a wireless indicator.

It is explanatory drawing of the planar state of a cholesteric liquid crystal.

21 is an explanatory diagram of a focal conic state of a cholesteric liquid crystal.

22 is a diagram illustrating an example of a reflection spectrum of the cholesteric liquid crystal.

It is explanatory drawing of the planar drive waveform with respect to a cholesteric liquid crystal.

24 is an explanatory diagram of a focal conic drive waveform for the cholesteric liquid crystal.

25 is a diagram illustrating the response characteristics of the cholesteric liquid crystal.

Fig. 26 is a structural example of a reflection type liquid crystal display element using a cholesteric liquid crystal.

It is explanatory drawing of the example of segment display using a cholesteric liquid crystal.

FIG. 28 shows a liquid crystal separation structure in a matrix substrate. FIG.

29 is a diagram illustrating a separation structure of two liquid crystals.

30 is a diagram illustrating an example of the pixel configuration in FIG. 29.

31 is an explanatory diagram of sub dot formation in FIG. 29.

32 shows a separation structure of three liquid crystals.

33 is a diagram illustrating the formation of dots in FIG. 32.

34 is a diagram illustrating formation of sub dots in FIG. 32.

35 is a diagram illustrating an example of superimposition display between a printed matter and a variable display element.

36 is a diagram illustrating a display state in FIG. 35.

It is a figure which shows the example of the superimposition display for the purpose of goods sale.

38 is a diagram illustrating an example of overlap display corresponding to a restaurant menu.

39 is a diagram illustrating an example of the overlap display corresponding to the schedule table.

40 is a diagram illustrating an example of overlap display corresponding to a map.

41 is a diagram illustrating an example of overlap display corresponding to a collection of problems.

42 is a diagram illustrating an example of overlap display corresponding to the simulation of bank loans.

43 is a diagram showing an example of a power supply circuit such as a non-contact IC card according to the third embodiment.

Fig. 44 is a diagram showing an example of a power supply circuit in which power supplies for logic and display are provided independently.

45 is a diagram showing an example of the configuration of a power supply circuit for a liquid crystal driver LSI that requires various types of voltage values.

46 is a configuration example of a circuit for limiting power supply to the display unit in accordance with the power supply amount.

47 is a configuration example of a clock output circuit that extends the drive period of the display section in accordance with the power supply amount.

48 is a structural example of a circuit which outputs an image display prohibition signal in accordance with an electric power supply amount.

Fig. 49 is a structural example of a current limiting circuit for a display power supply.

50 is an example of crest values in driving waveforms of a cholesteric liquid crystal.

Fig. 51 is an example of crest values in drive waveforms when the pulse width is widened.

52 shows an example in which the peak value of the drive waveform is changed linearly with temperature.

53 is a structural example of a temperature compensation circuit for realizing the characteristic of FIG.

54 is a block diagram of a configuration example of a liquid crystal display element driver in Example 4;

Fig. 55 is an explanatory diagram of a screen rewriting method according to the fourth embodiment.

56 is a time chart of the screen rewrite method of FIG. 55.

Fig. 57 is a diagram showing the polarity inversion scheme of the liquid crystal element drive waveform in Example 4;

Fig. 58 is an explanatory diagram (part 1) of the effect of the driving method in the fourth embodiment.

Fig. 59 is an explanatory diagram (part 2) of the effect of the driving method in the fourth embodiment.

60 is an explanatory diagram (part 3) of the effect of the driving method in the fourth embodiment.

61 is an explanatory diagram of a skip driving method as an image recording method.

62 is a flowchart of a skip driving method.

Fig. 63 is a diagram showing the first recording result in the three-value recording method.

64 is a diagram showing a second recording result in the three-value recording method.

65 is a block diagram of a configuration example of an automatic display device according to a fifth embodiment.

66 is a configuration example of an automatic display device wired to a terminal or the like.

67 is a configuration example of an automatic display device wirelessly connected to a terminal or the like.

68 is an example of the configuration of an automatic display device having a contactless IC card interface.

69 is a diagram illustrating an example of information of a data acquisition method and information of a data display style.

70 is an explanatory diagram (part 1) of an update date and time display form of data.

71 is an explanatory diagram (part 2) of an update date and time display form of data.

72 is an explanatory diagram of an automatic display device displaying a screen of a terminal or the like.

73 is an explanatory diagram of an automatic display device as a second display.

74 is an explanatory diagram of an automatic display device for displaying advertisement data.

75 is an explanatory diagram of an automatic display device used as conference distribution material.

Claims (3)

In the display element driving method of the matrix display device using a liquid crystal forming a cholesteric phase, A part of the scan electrode is set to the reset line and the write line in the selected state and the stop line in the non-selected state, respectively, A write data signal is applied to the signal electrode side while shifting the reset line, the stop line, and the write line, respectively. The write alternating current signal for the reset line and the write line in the selected state is polarized inverted within the first write time corresponding to the first line, and the first and second lines corresponding to twice the first write time. And a second recording time period combined with each other. In the display device using the liquid crystal which forms a cholesteric phase, A plurality of scan electrodes, A plurality of signal electrodes, A control unit for driving the plurality of scan electrodes and the plurality of signal electrodes, applying an alternating current signal to the liquid crystal, and writing data to the liquid crystal Including, The alternating current signal has a period of polarity inversion within the first recording time corresponding to the first line and has a period of a second recording time in which the first line and the second line corresponding to twice the first recording time are combined. Display device characterized in that. In a matrix display device using a liquid crystal forming a cholesteric phase, Scan electrode, Signal electrodes, A part of the scan electrode is set to a reset line and a write line in a selected state and a stop line in a non-selected state, respectively, and a write data signal is applied to the signal electrode side while shifting the reset line, the stop line and the write line, respectively. Control unit Including, The write alternating current signal for the reset line and the write line in the selected state is polarized inverted within the first write time corresponding to the first line, and the first and second lines corresponding to twice the first write time. And a second recording time period combined.

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