JPS63278894A - Card having display function and memory capacity - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to cards that have a memory capacity themselves, such as bank CD cards, IO cards for secrecy, and pre-sale cards for train tickets, etc. There are suggestions.

(Prior technology) For pre-sale cards such as bank CD cards and train tickets, magnetic tape is pasted on a board or resin board, and the magnetic tape is used to store account numbers, balances, etc. However, the storage capacity of magnetic tape is very small (it can barely remember several digits of numbers and symbols).

Furthermore, in this case, the contents stored on the tape could not be replaced at will.

What was devised to solve such problems is t!
There are EFROM (electrical rewritable ROM) cards (so-called IC cards) equipped with integrated circuits having memory.

[Problems they have]

In other words, IC cards were devised for the purpose of increasing storage capacity.
It was also possible to arbitrarily rewrite a large amount of stored content using integrated circuits. However, even if not all of the information stored in the card, even the minimum information that the card owner wants to know can only be learned by using a terminal device connected to a large computer and displaying it on the display device of the terminal device. It was something that could be done.

Therefore, the ability to display the memory contents on the card was required.

Therefore, it was necessary to form a display section and an information storage section on the same card.

As a part for performing this display, a liquid crystal display is most commonly used due to its display ability and power consumption.

In addition, the above-mentioned HEFROM is commonly used as a storage part due to its storage capacity, and creating these on the same card increases the number of steps.

Many technical problems arose, including a complicated card structure.

[Means for trying to solve problems]

The present invention solves these conventional problems, and as claimed in the claims, it comprises a pair of substrates, an electrode on the substrate, a liquid crystal aligning portion on the electrode, and a liquid crystal layer filled between the pair of substrates. , a card made of a liquid crystal material having ferroelectric properties and having a display function and a memory capacity, in which the electrodes have a matrix configuration or a shape of a character, symbol, etc., thereby displaying a character, symbol, etc. a liquid crystal display area;
By applying energy such as electricity, heat, or light to the liquid crystal layer from outside the card, external information is used as a signal to create an information storage area that can be written, erased, and rewritten using a liquid crystal material that exhibits ferroelectric properties. The invention consists of a card that has a display function and a memory ability.

In other words, the display area and memory area are constructed using the same ferroelectric liquid crystal, reducing the number of manufacturing steps.

Memory using this ferroelectric liquid crystal is
A patent application was filed by the same inventor as the present invention (Patent application filed in 1986).
130190) 1 There is an optical disk device that uses ferroelectric liquid crystal, and the reading, rewriting, and erasing of stored information are the same.

As shown in Figure 2, this memorization method means that liquid crystal molecules (I2) are placed at an angle of θ with respect to the layer normal of the smectic layer.
The state in which the liquid crystal molecules are tilted is defined as the first state, and the liquid crystal molecules in this state are changed to the second state in which they are at an angle of 10 with respect to the normal to the layer by applying electrical, thermal, or optical energy from the outside.

At this time, the difference in state is determined by detecting an optical change caused by the difference between the first state and the second state scale using an external detection means.

That is, the first state is O2 and the second state is 1, and information is stored as a signal.

A method for causing liquid crystal molecules to assume the first state and the second state will be explained with reference to a cross-sectional view of the storage area of this card shown in FIG.

First, the first method is to connect the upper and lower substrates (1) and (7
) is sufficiently shorter than the helical pitch of the ferroelectric liquid crystal (4) to achieve this state. This method is generally referred to as 5SFLC, and
The liquid crystal molecules are forced to adopt two states by force.

Next, as a second method, upper and lower liquid crystal alignment parts (3) are used.

(5) There is a method of attracting liquid crystal molecules by utilizing the difference in polarity caused by changing the materials used to achieve this state.
3) and (5) are formed into a laminated structure, and an electric field generated by storing charge in that part is applied to the liquid crystal (4), thereby causing the first state and the second state to be expressed. .

The present invention will be explained below with reference to Examples.

Embodiment FIG. 1A shows a card having a display function and a storage capacity using the ferroelectric liquid crystal memory of the present invention.

(B) shows its A-A' cross-sectional view.

Further, FIG. 3 shows a system using the card of the present invention.

. The memory card consists of a pair of opposing boards (4) and a board (lO
). Furthermore, a pair of transparent electrodes (5) and (9) are provided inside the pair. Furthermore, alignment treatment parts (6) and (8) are formed on the pair of electrodes.

Further, a PLC (7) is filled between the substrates.

The periphery of this memory card is sealed (10) to prevent the FLC from coming into contact with the atmosphere. The outer peripheral side of this memory card has external contact electrodes (5'), (9°) extending from a pair of electrodes (5), (9).

These external contact electrodes (5"), (9°) are connected to the lead terminals derived from the signal source (13) when writing and erasing memory (full-scale erasing), and a predetermined voltage is applied to it. will be carried out.

In this way, the system (101) is used to "write" information to the memory area whose entire surface is "0".

That is, a light beam, especially infrared rays, is directed from (19) to a mirror (18) and a half mirror (17) to the FLC arrayed in one direction over the entire surface, and then to a predetermined point via a condensing optical system, a position correction system (22), etc. At this time, upper and lower electrodes (5) perform writing by irradiating light to an address and shifting the state of liquid crystal molecules at a predetermined address from the initial state.

If a voltage lower than the inversion threshold voltage of the liquid crystal was applied during (9), information could be written more quickly and accurately. Further, the light passes through a mirror (16) and reaches a photosensor (14). Monitor whether information is being written here.

As a method for "reading" information, a semiconductor laser (2
1) The light beam emitted from the polarizing means (20).

The laser beam is incident on the memory card via a half mirror (17), a condensing optical system, and a position correction (auto tracking device) (22). Furthermore, the light that has passed through the storage area (3) of this memory card is reflected by the mirror (16).
), the polarizing means (15), and the light receiving sensor (14). A sensor (14) then detects whether the laser beam is transmitted or not and reads the information.

In this case, mirror (1
6), (17), (18) and optical system (22)
was moved relatively parallel to the card (1) to write or read information at a predetermined address.

That is, the card (1) may be moved mechanically, the mirror or optical system may be moved, or both may be moved simultaneously.

This memory card will be described in more detail below.

In this example, a plastic substrate or a Corning 7059 glass substrate (4), (10) was used as the substrate.

A transparent conductive film, tTO (in James oxide), is formed on this substrate by vacuum evaporation. An asymmetrical alignment film (6) is placed inside this pair of electrodes (5) and (9).
), (8) are provided, and a spacer (not shown) is interposed to form a liquid crystal cell with a substrate spacing of 2 μm.

FLC (7) is sandwiched between these. As an orientation treatment, 0.1μ of PAN (polyacrylonitrile) and PVA (polyvinyl alcohol) was applied on the counter electrode (5).
It was provided to the same thickness by a spin method, and then subjected to a known rubbing treatment. As an example of the rubbing process, a nylon cloth was rotated at 90 ORPM using a rubbing device, and the substrate was moved over the surface of the alignment film at a speed of 2 to 7 minutes to form a liquid crystal alignment part (6). In addition, an alignment film of an inorganic compound was formed on the other electrode (9) to form a liquid crystal alignment part (8) which was not subjected to rubbing treatment, and an FLC was formed between the liquid crystal alignment parts (6) and (8). For example, it was filled with biphenyl-based chiral smectic liquid crystal. Other than this, FLC such as BOBAMBC
Alternatively, it may be filled with FLC that is a blend of multiple liquid crystals.

An example of the threshold characteristic of this FLC is shown in Figure 4. In the same figure, by adding ±5V, the curve (24),
25) was obtained.

In other words, by inverting the liquid crystal molecules, light can be transmitted,
It has been found that it is possible to achieve non-transmission and at the same time obtain hysteresis, which exhibits a memory effect.

In FIG. 4, the vertical axis is the light transmittance.

In addition, as the display area section (2) of this card (1),
It has the same structure as the storage area described above.

However, in this example, a pair of electrodes (5).

(9) has a matrix configuration, and characters, figures, and symbols can be displayed using dots, and an IC for this purpose is provided on the card.

That is, the storage area section (3) and the display area section (2) of the card.
), all other structures are the same except for the shape of the electrodes, so it is possible to create a card that has both display and storage capabilities in the process of creating a conventional liquid crystal display device. It is something.

Now, as an example of how this display memory card is used, for example, when using it as a CD card for use at a bank, etc., the card owner goes to the bank, and the CD terminal connected to the computer is connected to the card's electrode (5'). , (9
power is supplied to the card through the card (°), and information such as the card owner, account number, past transaction details, etc. is extracted from the storage area of the card using an optical reading means. At the same time, new information is written by optical means and the necessary information is displayed on the card's display.

The liquid crystal used in this display is a liquid crystal that exhibits ferroelectricity (chiral smectic C liquid crystal), so when it is sealed in a parallel plate with a helical pinch or less, it has a stable biaxial position, and due to the electric field, One of the two directions can be selected. Moreover, even if the electric field is removed, it remains fixed in a stable position, and by combining it with a polarizing plate, it is possible to leave a display (such as letters).

Therefore, when the card is taken out of the CD terminal, no power is supplied to the card, and the memory remains in the ferroelectric liquid crystal storage area and ferroelectric display area.

In this way, the user can view the contents of the memory anytime and anywhere.

Although we have only shown how to use a bank CD card here, it is quite possible to use it for other purposes.

In this embodiment, the card of the present invention has a display area (2
) and the storage area section (3) are both shown in a transmissive format, but in addition to this embodiment, a reflective format may also be used without hindering the effects of the present invention.

In this case, since the laser beam is reflected at the electrode portion of the card, one of the substrates can be made of metal, and the card of the present invention can be manufactured at a lower cost.

Furthermore, when the card of the present invention is not provided with external electrode terminals, the memory of the card can be read without using any electrical connections, and in that case the storage section works as a ROM.

In addition, dichroic dyes are added to FLC, and guest-
It is also possible to store and display information in the host mode, and in this case, the device is characterized in that it only requires one or zero polarizing means.

〔effect〕

By inserting a display device using ferroelectric liquid crystal and a storage area inside the card, the card itself has a memory function compared to conventional magnetic card type cards, and the memory content of the card. It is now possible to check some or all of the information at any time through a display device without the need for a specific terminal device.

Also, since power is only needed when rewriting, there is no longer a need for a power supply inside the card.

In addition, since the storage area section and the display area section were able to be realized with the same structure, cards with two functions can be created in the same process as conventional liquid crystal display devices, and are inexpensive. It has become possible to realize a simple memory card that can be mass-produced.

The storage area of the present invention has the same structure as the display area, but the stored information is not exposed to the outside and cannot be seen unless it is read by a dedicated machine.
It can be used for 0 cards etc. In addition, since the display in this display area does not require a power source such as a battery or a control mechanism such as a CPU, the machine becomes simple and can be produced in large quantities at low cost. The reliability of the stored information is improved by the display means. In addition, LCD displays cannot be rewritten without applying voltage and heating, and are stable and do not lose their data even with changes in temperature that occur in daily life. It can be reused by modifying or changing it.

[Brief explanation of the drawing]

FIG. 1 shows a plan view and a sectional view of a card according to the invention. FIG. 2 shows the states of liquid crystal molecules. FIG. 3 shows the system of the card of the present invention. FIG. 4 shows the characteristics of transmitted light in the storage area of the card of the present invention. 1...Card 2...Display area section 3...Storage area section 4.10. ...Substrate 5゛, 9° ...External connection electrode 6.8 ...Liquid crystal alignment section 7.1 ...Liquid crystal

Claims (1)

[Claims] 1. A display function and a memory capacity made of a pair of substrates, an electrode on the substrate, a liquid crystal alignment section on the electrode, and a liquid crystal material having ferroelectricity filled between the pair of substrates. The card has a liquid crystal display area for displaying characters, figures, symbols, etc., and a liquid crystal display area for displaying characters, figures, symbols, etc., and a card for transmitting energy such as electricity, heat, or light, by having the electrodes in a matrix configuration or in the shape of figures, letters, symbols, etc. A display function and memory characterized by realizing an information storage area that can be written, erased, and rewritten by applying external information to the liquid crystal layer from outside the card as a signal, using a liquid crystal material exhibiting ferroelectric properties. A card with abilities. 2. In claim 1, the liquid crystal alignment unit limits the states that the liquid crystal molecules can take to only a certain plurality of states, and as long as energy such as electricity, heat, or light is not supplied from the outside. A card having a display function and a memory ability, which is characterized by having the ability to maintain a specific state.