JPS63280694A - 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 Application Field] The present invention is applicable to cards that have a memory capacity themselves, such as bank CD cards, ID cards for confidentiality, and pre-sale cards for train tickets, etc. There are suggestions.

[Conventional technology]

For pre-release cards such as bank CD cards, train tickets, etc., magnetic tape is pasted on a board or resin board, and the card with the ability to store account numbers, balances, etc. can be used on this magnetic tape. It is being said. However, the storage capacity of magnetic tape is very small and can only store numbers and symbols of several digits.

Further, in this case, the contents stored on the tape could not be arbitrarily rewritten.

EE was devised to solve such problems.
There are cards (so-called IC cards) equipped with an integrated circuit having FROM (electrically rewritable ROM) 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.

Furthermore, as the part that performs storage, the aforementioned EEFROM is generally used due to its storage capacity, and creating these on the same card increases the number of steps.

A number of technical issues were occurring, 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. In a card having a display function and a storage capacity made of a liquid crystal material having ferroelectric properties, a convex portion is provided between a pair of substrates and partitions the storage area between these substrates at a bit pitch interval, constituting an information storage section. The invention consists of a card having 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.

As mentioned above, there are several problems that must be overcome in order to put into practical use optical disk memories using ferroelectric liquid crystals. Examples include the following:

(1) Between disks, molecules must be correctly aligned in a region corresponding to at least one bit to form a monodoin.

(2) The storage area on the disk must be determined. That is, adjacent unit storage areas must be correctly separated, and even if access is made by mistake, it must be detected.

The present invention improves the above two points with a simple configuration.

Therefore, as mentioned above, this device is characterized by the provision of protrusions on the inside of the pair of substrates that partition the storage area at bit pitch intervals.

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).
No. 130190) 1 Optical disk device using ferroelectric liquid crystal, and the principle of reading, rewriting, and erasing stored information is the same as that of the present invention.

As shown in Figure 2, this memorization method means that liquid crystal molecules (12) are placed at an angle of θ with respect to the layer normal of the smectic layer.
The state where the liquid crystal molecules are tilted is defined as a first state, and the liquid crystal molecules in this state are changed to a second state in which the liquid crystal molecules are at an angle of 1 θ with respect to the normal to the layer by applying electrical, thermal, or optical energy from the outside.

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

That is, the first state is O1 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.

The first method is to create this state by making the distance between the upper and lower substrates (1) and (7) sufficiently shorter than the helical pitch of the ferroelectric liquid crystal (4), and this method is generally used. It is called 5SFLC, and liquid crystal molecules are forced into two states by force from the interface (substrate).

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

(5) A method of attracting liquid crystal molecules to create this state by utilizing the difference in polarity generated by changing the materials used, and a third method/method is a liquid crystal alignment part (3). (5) is made into a laminated structure, and an electric field generated by storing charge in that part is applied to the liquid crystal (4),
A method of developing the first state and the second state is known.

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 (10).
). 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, on the liquid crystal alignment section (8), there are provided convex sections (23) that partition the storage area section at uniform intervals. In the drawing, the size is enlarged and the intervals are widened for convenience. In reality, protrusions (23) are provided every few μm, and partition the storage area of the card in a direction parallel to one direction around the card.

Further, FLC (7) is filled between the substrates.

The periphery of this memory card is sealed (11) to prevent the FLC from coming into contact with the atmosphere. The outer peripheral side of this memory card has external contact electrodes (5') and (9') extending from a pair of electrodes (5) and (9).

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

In this way, information is "written" into 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. Writing is performed by irradiating light to an address and shifting the state of liquid crystal molecules at a predetermined address from the initial state. At this time, if a voltage lower than the threshold voltage for inversion of the liquid crystal was applied between the upper and lower electrodes (5) and (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 (1).
6), the polarizing means (15), and the light receiving sensor (14).
leading to. 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.

The amount of liquid crystal (7) on the convex part (23) which is used when writing and reading this information is the information storage part (26).
If the writing light and the reading light miss the information storage section (26) because the light is small compared to , or does not exist at all, when that light reaches the photosensor (14),
No optical change is obtained due to the optical anisotropy of the liquid crystal material, and the light is either transmitted or non-transmitted (polarizing means (15), (
Only the state (20) can be obtained depending on the combination of (20) and (20). This is detected electrically and the position of the mirror and optical system is corrected to produce the writing light.

It becomes possible to accurately irradiate the information storage section (26) with the readout light.

Further, even if the convex portion is made of a reflective material, similar positional correction can be performed.

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.

ITO (indium tin oxide), which is a transparent conductive film, is formed on this substrate by vacuum evaporation. An asymmetrical alignment film (6) is placed inside this pair of electrodes (5) and (9).
), (8), and a height of 1 above the alignment part (8).
．． Convex portions (23) having a width of 5 μm and an interval of 5 μm at 3 μm intervals were formed from photosensitive polyimide resin. At this time, after applying photosensitive polyimide to the front surface, a predetermined pattern was formed using a photomask. Next, 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, PAN (polyacrylonitrile) and PVA (polyvinyl alcohol) were provided on the counter electrode (5) to a thickness of 0.1 μm by a spin method, and a known rubbing treatment was performed. As an example of the rubbing process, a nylon cloth is rotated at 90 ORPM in a rubbing machine,
The substrate was moved on the surface of the alignment film at a speed of 2 m/min to form a liquid crystal alignment part (6). Also, the other electrode (9
), an alignment film of an inorganic compound was formed on top of the liquid crystal alignment section (8) which was not subjected to rubbing treatment.

FLC, for example biphenyl chiral smectic liquid crystal, was filled between the liquid crystal alignment parts (6) and (8). Other than this, FLC such as BOBAMBC or FLC blended with a plurality of liquid crystals may be filled. An example of the threshold characteristic of this FLC is shown in FIG. In the same figure, curves (24) and (25) could be obtained by adding ±5v. That is, it has been found that by inverting the liquid crystal molecules, it is possible to transmit or not transmit light, and at the same time to 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 nine characters, figures, and symbols can be displayed using dots. Also, 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.

In addition, the liquid crystal molecules (12) have the ability to align themselves along this convex portion (23), and this allows the information storage portion (26
)6? & Crystal molecules obtain a good orientation state with no defects, and information can be stored accurately.

Further, this convex portion (23) could also serve as a spacer for the liquid crystal cell, and in that case, it was possible to manufacture it at low cost with fewer steps.

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'), and information such as the card owner, account number, past transaction details, etc. is extracted from the storage area of the card by 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 pitch 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, power is no longer 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〕

Tracking of the storage area of the card and alignment defects of the liquid crystal could be easily eliminated by the configuration of the present invention.

In addition, since we were able to realize the storage area and display area of the card with the same structure, cards with two functions can be created in the same process as conventional liquid crystal display devices, making it possible to create cards at low cost. , it became possible to realize a simple memory card that can be mass-produced.

The storage area section of the present invention has the same structure as the display area section, but all the stored information C (not displayed externally,
Since it cannot be recognized unless it is read by a special machine, it can be used for ID cards, etc. In addition, the display in this display area does not require a power source such as a battery, and there is no need for a control machine such as a CPU, so the machine is simple and can be produced in large quantities at low cost. The reliability of stored information is improved by the means and the display means. In addition, liquid crystal displays and memories cannot be rewritten without applying voltage and heating, and are stable without data being removed even with temperature changes that occur in daily life. It is possible to reuse it 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. ... Board 5'+9' ... External connection electrode 6.8 ...
...Liquid crystal alignment part 7...Liquid crystal 23...Convex part

Claims (3)

[Claims] 1. A card comprising a pair of substrates, an electrode on the substrate, a liquid crystal alignment section on the electrode, and a display area and a storage area made of a liquid crystal material having ferroelectric properties filled between the pair of substrates. 1. A card having a display function and a storage capacity, characterized by having a convex portion provided between substrates, partitioning a storage area between the substrates at bit pitch intervals and constituting an information storage section. 2. In claim 1, the liquid crystal alignment unit limits the states that liquid crystal molecules can take to only a plurality of specific states, and the liquid crystal alignment unit limits the states that the liquid crystal molecules can take to only a plurality of specific states, and the liquid crystal alignment unit is configured to limit the states that the liquid crystal molecules can take to only a plurality of specific states, and to maintain the specified state unless energy such as electricity, heat, or light is supplied from the outside. A card having a display function and a memory ability, characterized in that it has the ability to maintain the state of. 3. 2. A card having a display function and a storage capacity according to claim 1, wherein the convex portion constituting the information storage section also serves as a spacer for keeping the distance between the pair of substrates constant.