JPH0257396A - Information recording and display card - Google Patents

Abstract

PURPOSE:To reversibly display and erase visible information such as characters, numerals, figure, etc. having high reliability in a simple and inexpensive structure by disposing an invisible information record and a rewritable visible information display on a card board mainly made of specific polymer nematic liquid crystal. CONSTITUTION:An invisible information record 2 is disposed on the front face of a card 1, and a visible information display 3 mainly made of a polymer nematic liquid crystal is disposed on the rear face. The display 3 employs a polymer nematic liquid crystal in which isotropic transferring temperature Tcl for selectively taking a transparent state and an opaque state at an ambient temperature by reversibly dislocating its state by light or heat is presented at higher temperature side from a glass transition temperature Tg. If heat exceeding the temperature Tcl is applied to the display 3 by a thermal head or a light irradiation, information recorded on the record 2 is displayed. Similarly, after it is heated to the temperature Tcl by the heat or light radiation, it is erased by annealing. The display and the erasure can be reversibly conducted repeatedly any times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to information recording cards such as optical cards, IC cards, and magnetic cards.

[Summary of the invention]

The present invention provides an information recording card having an invisible information recording section such as an optical card, an IC card, or a magnetic card.
) is equipped with a rewritable visible information display section mainly made of polymer nematic liquid crystal whose temperature is higher than the glass transition temperature (Tg). It is possible to reversibly display and erase information based on the recorded content or the content recorded inside the card reader/writer or on a storage device connected to the card reader/writer.

[Conventional technology]

Credit cards that have individual information recorded on them and allow you to purchase goods on the spot without having to pay cash; cash cards that allow you to withdraw cash from your account using an unmanned cash dispenser; and cards that have a fixed fee in advance. Various information recording cards are widely used, such as prepaid cards that allow you to pay in advance and use telephone calls and vehicles up to a certain limit, and hospital management cards that serve as patient medical records at medical facilities.

Types of such information recording cards include magnetic cards that record information on a magnetic recording medium stripe using a magnetic head;
There are IC cards in which a C chip is embedded and electrically recorded, and optical memory cards (optical cards) in which an optical recording medium is provided and optically recorded using a laser beam or the like. Magnetic cards are currently widely used, but IC cards have a storage capacity more than 100 times that of magnetic cards, and optical cards have an I
It has a storage capacity more than 50 times that of the C card, and is expected to be a new next-generation card with more advanced functions.

However, the information recorded on these information recording cards is
Whether it is a magnetic card, an IC card, or an optical card, it is not possible to directly check the recorded contents with the naked eye. Therefore, it would be very convenient for the user if the information recorded on the card or a part of the information could be displayed directly on the card in a visually visible manner. For example, a credit card shows the payment due date and amount, a cash card shows the balance in the account and the transfer destination, a prepaid card shows the available balance and expiration date, and a hospital managed card shows the amount to be paid at the counter and the next payment. If the hospital entrance is displayed, the card will have more advanced functions and will benefit the user, such as preventing troubles such as inability to pay due to insufficient balance.

Therefore, conventional methods have been proposed for this purpose, such as an embossing method in which letters are pressed directly onto a plastic card substrate to print irregularities, and a method in which a printer is used to print on the surface of the card substrate each time it is used.

However, with these methods, the displayed information cannot be erased, and the area that can be displayed on the card is limited, so once a predetermined number of lines have been printed, the display function of the card disappears. The drawback was that the card had to be replaced with a new one.

Therefore, the following information recording/displaying cards have been proposed that eliminate this drawback and allow information to be displayed and erased repeatedly.

According to Japanese Unexamined Patent Publication No. 63-3393, a device is proposed in which necessary information is visually displayed using a liquid crystal display panel having, for example, a twisted nematic structure provided on an IC card substrate.

Also, JP-A No. 63-4220 and JP-A No. 63-4221
In the publication, a method is devised in which a surface-stabilized ferroelectric liquid crystal element is provided on a card substrate, and information is displayed by applying an electric field and simultaneously irradiating laser light.

On the other hand, there are displays using electrochromic materials (Japanese Unexamined Patent Publication No. 61-270195), displays using photochromic materials (Japanese Unexamined Patent Publications No. 62276142 and Japanese Patent Application No. 62-44716), and still others.
An idea has been devised (Japanese Unexamined Patent Publication No. 62-233296) in which a small piece of ZT translucent porcelain is provided on a card substrate and an electric field is applied thereto to display information by the birefringence phenomenon.

[Problem to be solved by the invention]

The previously proposed methods for providing the above-mentioned rewritable visible information display section on the information recording card board have various drawbacks as described below, making it difficult to put them into practical use. .

For example, a liquid crystal display panel with a twisted nematic structure has a complicated electrode structure for driving, and requires a built-in power source such as a lithium battery inside the card.

Furthermore, according to the surface-stabilized ferroelectric liquid crystal display element,
Although its bistable feature eliminates the need for a built-in power supply, it does require two polarizers. Furthermore, the cell structure is complex, as it is necessary to precisely create a cell gap of about 2 microns, and the shock of dropping or hitting the card can disrupt the alignment of the liquid crystal, making it impossible to display. .

Furthermore, those made of photochromic materials have problems with weather resistance, particularly in that they fade due to light, and those made of electrochromic materials have a complicated electrode structure for applying an electric field for coloring and decoloring.

Furthermore, the structure using P L Z T translucent porcelain pieces requires electrodes and two upper and lower polarizing plates, making the structure complicated.

Each display element as described above has a built-in power supply, driving electrodes,
In view of the drawbacks that polarizing plates and the like are required and the structure is complicated, the problem to be solved by the present invention is to provide a simple and inexpensive structure that can reversibly remove unreliable visible information such as letters, numbers, and figures. The objective is to provide an information record display card that can be displayed and erased automatically.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the information record display card according to the present invention has an invisible information recording section and information recorded in the invisible information recording section that can be easily viewed. A rewritable visible information display section, which is mainly made of polymer nematic liquid crystal whose isotropic phase transition temperature is higher than the glass transition temperature, is disposed on a card substrate.

[Function] The information recording/displaying card according to the present invention has the information recorded in the invisible information recording section stored in the visible information display section disposed on the card substrate, for example, in the visible information display section disposed on the card substrate. Letters, numbers, figures, etc. are displayed in a visible state by heat supplied from the thermal head of a thermal printer, or by light irradiation such as flash light through a negative mask, and also by heat or light irradiation. It is erased by annealing. Displaying and erasing is reversible and can be repeated any number of times.

〔Example〕

Hereinafter, a write-once (DRAW) type optical card having a rewritable visual information display function according to the present invention will be taken as an example and explained with reference to the drawings.

Fig. 1 a showing the external appearance of the information recording display card according to the present invention;
In FIG. 1, an invisible information recording section 2 is disposed on the front surface of the card, and a visible information display section 3 mainly composed of polymer nematic liquid crystal is disposed on the back surface of the card. The structure of the card will be explained in more detail based on the sectional view shown in FIG. 2a.

A light and heat reflective layer 4 made of, for example, an aluminum vapor-deposited film, a visible information display section 3 mainly made of polymer nematic liquid crystal, and a first protective layer 61 are sequentially laminated on a first card substrate 51 made of, for example, a polyethylene terephthalate film. .

On the other hand, the invisible information recording section 2 is disposed on the other surface of a second card substrate 52 made of, for example, a polycarbonate plate with a second protective layer 62 on its surface, and the invisible information recording section 2
1 and the invisible information recording section 2 are bonded together via an adhesive layer 7.

As the visible information display section 3, a polymer nematic liquid crystal which undergoes a reversible phase transition by light or heat and selectively assumes a transparent state and an opaque state at room temperature was used. This polymer nematic liquid crystal is a cyanobiphenyl type, azomethine type, phenylbenzoate/azomethine type, or a copolymer type of cyanophenyl benzoate and methoxybiphenyl benzoate, etc. having the following molecular structures (a) to (d). A chain-type polymer nematic liquid crystal is suitable.

(a) Cyanobiphenyl system (b) Azomethine system (m is an integer) (C) Phenylbenzoate/azomethine system (d) Copolymerization system of cyanophenyl benzoate and methoxybiphenyl benzoate Examples of these (a) to (d) In chain-type polymer nematic liquid crystals, the thermal motion of the mesogen in the side chain is decoupled from the thermal motion of the carbon-carbon bond in the main chain by medilene bonds, so that high-speed phase transition behavior can be achieved.

Furthermore, the side-chain polymer nematic liquid crystals according to the examples (a) to (d) are characterized in that the isotropic phase transition temperature Tel exists on the higher temperature side than the glass transition temperature Tg. Therefore, at room temperature below the glass transition temperature TF, phase transition does not occur and display information is stably stored.

In this example, the cyanobiphenyl polymer nematic liquid crystal (a) was used as an example. This synthesis method will be briefly described. The side chain portion is 4-n-(1-hydroxypentyloxy)-4′cyanobiphenyl ( 3) was synthesized. Next, the above (3) was reacted with acrylic acid chloride (4) serving as a main chain portion to synthesize an acrylate liquid crystal monomer (5).

Next, by radical polymerization of the liquid crystal monomer (5), a cyanobiphenyl polymer nematic liquid (a) having an average molecular weight of 3.2×10′ was obtained. The glass transition temperature T g of this cyanobiphenyl polymer nematic liquid crystal (a) is 40'
The C1 isotropic phase transition temperature '1-c I was 124°C. This synthesis followed the method of Shibaev et al. (V
,P,5hibaev et al., ,Eur,Pol.
ym, J., 18+651 (1982)).

Next, the principle of operation of displaying and erasing the visible information display section 3 mainly composed of the polymer nematic liquid crystal will be explained based on FIG. 3. These figures show the phase transition behavior of polymer nematic liquid crystals, with the horizontal axis representing temperature and the joint axis representing free energy.

Immediately after the first JU piece coating and drying, the film consisting mainly of polymeric nematic liquid crystal has an isotropic amorphous glass phase F, is optically transparent, and cannot display information as it is.

To achieve this, the isotropic amorphous glass phase F is first heated to a temperature close to the isotropic phase transition temperature Tel or exceeding 'Fcl, and then slowly cooled and annealed to form a minute liquid crystal domain, which allows light of 600 nm or less to emit light. It scatters, making it appear cloudy.

This phase is called liquid crystal glass phase A. This phase is the background of characters, numbers, figures, etc. displayed in the visual information display. By making the entire visible information display section 3 a cloudy, opaque liquid crystal glass phase A, preparation for information display, that is, initialization, is completed.

This will be explained based on the display in FIG. 3a. When the visible information display part 3 in the cloudy and opaque liquid crystal glass phase A is heated by applying a thermal head or a light beam, that part becomes liquid crystal phase B at a point exceeding the glass transition temperature Tg, and further changes to an isotropic phase. When the dislocation temperature T e I is exceeded, the liquid crystal phase enters the region of unstable liquid crystal phase C. However, since the C phase is in an unstable state with high free energy, it immediately transitions to an isotropic liquid phase, which is a low energy phase.

When the D phase is rapidly cooled, it becomes an unstable isotropic phase E, but because it passes through this phase in a very short time, the transition to the more stable liquid crystal phase B is suppressed, and it becomes a transparent isotropic phase in an instant (within a few m sec). The phase shifts to crystalline glass phase F, and the displayed information is frozen and stored.

This will be explained based on Figure 3 of Shōo. The display information in the transparent isotropic amorphous glass phase F described above becomes an unstable isotropic phase E when it is heated by applying a thermal head or light beam, etc., when it exceeds the glass transition temperature Tg, and further reaches the clearing point Tel. reach.

When it is slowly cooled and annealed from a temperature in the vicinity of this temperature, it passes through the liquid crystal phase B, which has a small free energy, and is fixed to the liquid crystal glass phase A at room temperature. At this time, the visible information display section returns to its cloudy and opaque initialized state within a few seconds, the past display information is completely erased, and the next display can be performed again.

Displaying and erasing can be repeated repeatedly.

Here, regarding the phase transition behavior of this polymer liquid crystal, the third
It was announced by Nito et al. in lecture number 29, page 18 of the Proceedings of the 4th Applied Physics Research Conference (Spring 1986), and its application as an information recording material was also devised by Nito et al. Application No. 62-23990) Now, regarding the specific method of arranging this cyanobiphenyl polymer liquid crystal as the visible information display section 3 of the information recording display card shown in FIG. 1, the information shown in FIG. The explanation will be based on a cross-sectional view of the record display card.

The synthesized cyanobiphenyl polymer liquid crystal is dissolved in a solvent such as cyclohexane, and this solution is used to reflect light and heat on a first card substrate 51 made of a 50 μm thick polyethylene terephthalate film on which a light and heat reflective layer 4 has been formed by vapor deposition of aluminum, for example.゛Coat on the layer 4 side.

The thickness of the coating film after drying was 6 μm. A first protective layer 61 made of an acrylic hard coat film having a pencil hardness of 2H was provided with a thickness of 2 μm on the surface of the visible information display section 3 made of the cyanobiphenyl polymer nematic liquid crystal coating film.

On the other hand, the invisible information recording section 2 was provided on a second card substrate 52 made of a polycarbonate plate with a thickness of 700 am.

Here, Sb, Se, 1, and Bi2Te2 were deposited on 52 in this order. Details of this 5bzSes/BitTea two-layer material, which is a write-once (DRAW type) optical recording medium, are reported by Y., Aoki et al.
Proc.

5PIE, Danhong, 313 (1983)). The invisible information recording section 2 and the first card substrate 51 are bonded together using a urethane-based adhesive layer 7. A second protective layer 62 made of an acrylic hard coat film is formed on the surface of the second card substrate 52.
was provided with a thickness of 2 μm, and an information recording display card was completed.

In this embodiment, a method for displaying and erasing information on the visible information display section 3 using heat from a thermal head will be described. In the information recording/displaying card completed as described above, each time it is used, the invisible information recording section 2 records, for example, the payment amount and account balance as a dot array using a laser beam device built into the card reader/writer. . The visible information display section 3 also displays information such as the content recorded in the invisible information recording section 2 or the content recorded inside the card reader/writer or the storage device connected thereto, such as when the balance amount is the same. (Written by a printer with a thermal head built into the card reader/writer. This display information is written at 120°C by a thermal head, etc.)
Can be erased by thermal annealing from nearby areas, and can be repeatedly displayed/
Erasure was possible. The contrast ratio of the display was 10.

Disaster Spotting 1 In this example, a card structure in which a photothermal conversion dye is contained in a reversible photothermal recording layer mainly composed of polymeric nematic liquid crystal and display by light irradiation is explained with reference to Figure 2. do. The cyanobiphenyl polymer nematic liquid crystal described in Example 1 and Sudan I in an amount equivalent to 5% by weight of the cyanobiphenyl polymer nematic liquid crystal were mixed with cyclohexane or the like. The photothermal conversion dye is dissolved in a container and coated with this solution on the photothermal reflective layer 4 side of the first card substrate 51 made of a 50 μm thick polyethylene terephthalate film on which the photothermal reflective layer 4 has been provided, for example, by vapor deposition of aluminum. The visible information display section 31 contained the above information. The thickness of the coating film after drying was 6 μm. As in Example 1, a first protective layer 61 with a thickness of 2 μm was provided on the surface of the visible information display section 31 containing the photothermal conversion dye. On the other hand, Sb, Se, and BizTe are placed on a second card substrate 52 made of a 700 μm thick polycarbonate plate.
= and were deposited in this order to provide the invisible information recording section 2.

The invisible information recording section 2 and the first card substrate 51 are adhered to each other by a urethane adhesive layer 7, and a second protective layer 62 with a thickness of 2 μm is provided on the surface of the second card substrate 52 to record the information. Completed record display card.

In this embodiment, a method using flash light will be described as a display method on the visible information display section 31 containing a photothermal conversion dye. A negative mask is brought into close contact with the surface of the first protection 161, and information such as letters, numbers, figures, etc. is displayed through the mask by means of flash light to the visible information display section 31 containing a photothermal conversion dye.
exposed to light. As a flash light source, TORAPEN-UPTU-250 manufactured by Riso Kagaku Kogyo was used. The exposed area is heated to a temperature exceeding Tel by the photothermal energy conversion action of the photothermal conversion dye, and then rapidly cooled to become an isotropic amorphous glass phase F, displaying visible information, and this display information is transmitted by flash light or a thermal head. It was confirmed that it could be erased by thermal annealing at around 120''C.

Display and erasing could be repeated, and the contrast ratio of the display section was 10.

Although the information recording and display card according to the present invention has been described above based on the embodiments, the light and heat reflective layer 4 can be omitted to simplify the production process. In this case, since the surface of the invisible information recording section 2 on the BizTei side also serves as a light and heat reflecting layer, the first card substrate 51 and the adhesive layer 7 are made of a transparent material that does not contain pigments or the like. At this time, the display contrast ratio was 8, which was sufficient for visual observation.

In addition, as in Example 1, when displaying and erasing using a thermal head is used, it is desirable to provide a first protective layer 61 in order to prevent thermal deformation of the surface of the visible information display section due to contact with the thermal head. However, when displaying is performed using Franche light as in the second embodiment, the first protective layer 61 can be omitted for simplicity.

Furthermore, in this embodiment, the visible information display section was provided at the stage of creating the information record display card, but apart from this, the visible information display section was provided on the board surface of the already completed information record card (as shown in Fig. 4). There is also a method of cutting an adhesive film 11 having a visible information display section 3 mainly made of polymeric nematic liquid crystal into a predetermined size and pasting it.In this case, the visible information display section also contains a photothermal conversion dye. If the flatness of the surface of the information recording card is affected by pasting the adhesive film, as shown in the cross-sectional view of the card in FIG.
It is sufficient to make a recess at the position where the information recording card 10 is to be pasted.

Furthermore, in this embodiment, as shown in FIG. 1a and FIG. As long as they are not damaged, they may be placed on the same side of the card, as shown in Figure 1C. In this embodiment, the invisible information recording unit 2 has 5bzse:+/
A BizTez 2 N-based write-once optical recording medium was used, but in addition, 5bzSe:+/BizTez/5b2Se3
A three-layer write-once optical recording medium may also be used (for detailed characteristics, see Proc, 5IPE, Tan 29).

76 (1985) by Y. Nakane et al.).

In addition, write-once optical recording materials based on tellurium compounds such as TeC and TeOx, and organic dyes such as cyanine and phthalocyanine may also be used.

In addition to write-once optical recording materials, we also offer rewritable (
E-DRAW type) optical recording materials such as a TbFeCo-based magneto-optical recording material, a chalcogenide-based phase change type recording material, etc. may be used as the invisible information recording section 2.

Furthermore, a read-only (ROM type) optical card may be provided with a visible information display section.

Of course, it is not limited to optical cards, but cards with invisible information recording sections such as magnetic cards, IC cards, etc. A visible information display section is provided in a place that does not impair the information recording function on the card board, such as a magnetic stripe, IC memory, etc. It is also possible to display information based on the content recorded in the card reader/writer, or even based on the content recorded inside the card reader/writer or in a storage device connected to the card reader/writer.

〔Effect of the invention〕

As described above, according to the present invention, information based on the contents recorded on an information recording card such as an optical card, an IC card, or a magnetic card can be directly viewed on the visible information display section disposed on the card board. It can be displayed in any state. This allows the card user to know at a glance information based on the contents recorded on his or her card. Moreover, information displayed in the past can be deleted, and display and deletion can be performed any number of times.

The visible information display section can be easily placed on the card substrate by coating with a solution mainly made of polymer nematic liquid crystal, and the visible information display section made mainly of polymer nematic liquid crystal can be placed on the surface of an already completed information recording card. Another feature of the present invention is that it can be used as an information recording display card by pasting an adhesive film equipped with the same.

Furthermore, it does not require a built-in power supply, driving electrodes, polarizing plates, etc., has a simple structure, and can be manufactured at low cost.

The polymer nematic liquid crystal used in the present invention has a glass transition temperature Tg of 40°C or higher, and is a solid with the thermal movement of the main chain and side chains frozen at room temperature, so it has high display storage stability and mechanical It is stable against mechanical shock and bending distortion.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an external appearance example of an information recording display card to which the present invention is applied, FIG. 2 is a sectional view showing an example of an information recording display card according to the present invention, and FIG. 3 is a polymer polymer to which the present invention is applied. This is an explanatory diagram of the operation of displaying and erasing information on a visible information display section using a nematic liquid crystal, where a is an explanation of the display operation, b is an explanatory diagram of the erasing operation, and Fig. 4 is a diagram showing how the visible information display section is attached to an already completed information recording card. FIG. 5 is a cross-sectional view of a card showing an example of the adhesive polymer nematic liquid crystal film shown in FIG. 4 attached. 1----------- Information record display card 2-111--1111 Invisible information recording section 3--
-Visible information display section 31--Visible information display section 4 containing photothermal conversion dye--Photothermal reflective layer 7--m---- -Adhesive layer 11...--Adhesive polymer liquid crystal film 51-
-----First card board 52--
1-----Second card board 6t----------
・First protective layer 62- ...Second protective layer Skin surface Back side I A plan view showing the Tato view 111 of the card showing the 1st or 11th plaster suction record display card. Figure 2: RT Tg TcL 8 Table of Contents Cross section showing an example of WJd publication of Uraun Card visit diagram Figure 5 Procedure line 1 ￥j TE letter (voluntary) 6. Target of amendment July 1931/λshi date

Claims (1)

[Claims] An information recording display card characterized in that an invisible information recording section and a rewritable visible information display section mainly made of polymer nematic liquid crystal whose isotropic phase transition temperature is higher than the glass transition temperature are arranged on a card substrate. .