JPS59193558A - Optical card - Google Patents

Abstract

PURPOSE:To enable easy guide of an optical head to a track by forming a funnel-shaped guiding part for guiding the optical head to the track on a titled card. CONSTITUTION:Plural grooves 26 are formed on a card-shaped base plate 25. A funnel-shaped recess 27 having an easily formable rectangular section is formed at each end of the grooves 26, and both are connected to each other. An org. monolayered film 28 contg., for example, benzoindoline dye is formed as an optical recording member over the entire surface in which the grooves 26 and the recesses 27 of the plate 25 are formed. Since the plane of the recess 27 is funnel-shaped, a funnel-shaped region having high reflectivity is formed on the film 28 to provide a guiding part G for guiding an optical head. The thickness of the org. monolayered film is different in the part where the groove 26 exists and the other part and a difference in reflectivity exists between both parts. The optical head is thus guided by the difference in the reflectivity between the two parts. Said part is a track T for guiding the optical head.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to an optical card having an optical recording member that records information on the surface or inside of the recording material by thermal action by selective irradiation of laser light on a card-shaped substrate. More specifically, in an optical card comprising a track for guiding an optical recording and reading device and a guide portion for guiding the optical recording and reading device to the track, the shape of the guide portion is shaped like a funnel. The present invention relates to an optical card characterized by the following.

[Background technology]

Generally, magnetic recording and reproducing methods are widely known for recording and reproducing information. One example of this use is the magnetic card used in bank deposit money cards.

FIG. 1 shows an example of a conventional magnetic card. In the figure, the magnetic card has a structure in which a magnetic recording material 2 is provided on the surface of a card-shaped mount 1, and transparent protective stickers 3 are attached to both sides of the mount 10. As is well known, the magnetic recording/reproducing method allows information to be easily recorded, erased, and re-recorded.

Therefore, if a magnetic card using the above method is placed in a magnetic field caused by a misused card or a magnet, the information recorded on the card will change, resulting in low information reliability. Also,
Due to the limitations of the magnetic head, magnetic cards can only record low-density information, and furthermore, due to limitations based on the size of the card,
The drawback is that only a very small amount of information can be recorded.

Therefore, it is impossible to take a complicated signal form to prevent misuse due to the above-mentioned limitations on the magnetic card.

In order to improve these drawbacks, recording and reproducing systems based on optical principles have recently been proposed.

A card using this optical recording and reproducing method is called an optical card.

FIG. 2 shows an example of an optical card.

In the figure, the optical card has a structure in which an optical recording member 5 is provided on the surface of a card-shaped substrate 4, and a waist-retaining member 6 that is transparent to recording light and reproduction light is provided on the optical recording member 5. 0 Next, each part will be explained. The substrate 4 serves to mechanically support the optical recording member 5, and is made of, for example, a glass material such as polyester. Optical recording member 5
is a part for recording information, and is formed of, for example, a metal thin film or a synthetic resin containing silver particles.A particularly suitable optical recording member 5 is an organic monolayer film containing a cyanine dye, for example, benzoindo-1 horns. be. The benzoindoline dye has a large optical absorption rate for the laser beam with a wavelength of 830 nm emitted from a semiconductor laser, and a large reflectance of about 30 to 40 nm for the laser beam of the same wavelength. Benzoindoline dye, stable 1
j and the binder, such as nitrocellulose, is p-
By mixing α-methylstyrene and applying it to the surface of the substrate 4, the thickness of the 0-optical recording member 5 formed as an organic single layer ++175i is, for example, about 0.07 to several μm. . The protective member 6 is made of a material that is transparent to a laser beam for recording and reading, for example. The thickness of the protective member 6 made of acrylic resin or the like is, for example, about 0.2 to 0.5 mm. Explaining the method for recording and reproducing information 0 To record information, a laser beam modulated according to the information is focused through an optical head into a minute light spot with a diameter of about 1 to 5 μm, and this laser beam 7 is used. This is done by forming fine holes 8 (hereinafter referred to as bits) in the optical recording member 5 on the substrate 4. To reproduce information, a weak laser beam for reading is focused on a light spot and the optical recording member 5 is
The optical recording member 5 is irradiated with light and reflected light or transmitted light obtained through bits formed on the optical recording member 5 is detected. For example, while the optical recording member 5 has a reflectance of about 40% with respect to the laser beam for reading υ, the reflectance of the bit 8 decreases to about 6 to 25%. Therefore,
The recorded information can be read by the difference in reflected light.

In the explanation of FIG. 3 (α) above, the recording and reproducing laser beam 7 was irradiated from the protection member 6 side, but FIG. 3 ψ
), the substrate 4' is transparent to the laser beam.
It is also possible to record and reproduce information by irradiating the laser beam 7' from the substrate 4' side.

FIG. 4 shows an example of an optical card on which information is recorded. In the figure, bits 8 each having a diameter of, for example, about 1 to 5 μm are formed on an optical recording member 5 in a plurality of rows 9 (hereinafter referred to as bit rows). Although information is read by moving the optical head in the direction of arrow 10, the optical head may be fixed and the optical card may be moved.

As explained above, since an optical card is an optical recording member in which information is recorded in the form of minute holes, the information is highly reliable because it is not erased by magnetic fields or the like. Further, since the diameter of the pores is as small as, for example, about 1 to 5 pm, the information density can be increased.

Therefore, the optical card can be used as a cash card, ID card, commuter pass, or the like.

In the above optical card, information is recorded and read using an optical head. However, in order to accurately record and reproduce information at a predetermined location, it is necessary to accurately move the optical head along the area where the information is recorded, that is, to perform tracking control. The above-mentioned optical card does not have a special track for guiding the optical head, and information is recorded and reproduced depending only on the mechanical precision of the optical head.

In order to improve the above-mentioned drawbacks, an optical card has been proposed in which an optical card substrate is provided with a groove for optically guiding an optical head, that is, a tracking groove.

FIG. 5 is an example of an optical card in which a tracking groove is provided on the substrate. In the figure, the optical card includes a substrate 11 made of a material transparent to recording light and reproducing light. A plurality of tracking grooves 12 are formed in parallel at a predetermined pitch on the substrate 11. An optical recording member 13 is provided on the surface of the substrate 11 on which the grooves 12 are formed.

Furthermore, a protective layer 14 is formed thereon. Groove 12
The width is, for example, about 2 to 5 μm, and the depth is, for example, about 2/8 rL (where λ is the wavelength of the laser beam, and L is the refractive index of the substrate 11). In this optical card, information is recorded and reproduced by irradiating the substrate 11 with a laser beam. The tracking groove 12 may be formed to extend to the end of the substrate.Furthermore, the optical recording member 13 may be formed on the entire surface of the substrate 11.

Next, an example of a tracking method will be described below regarding an optical card equipped with a substrate on which tracking grooves are formed.

FIG. 6 is a principle diagram showing an example of a tracking method.

In the figure, a laser beam emitted from laser device #16 passes through a collimator optical system 17 and other optical systems 18, is reflected by a movable reflecting mirror 19, is input to a polarizing beam splitter A1, and is input to a wavelength plate A2. via lens 2
0-1 and enters the tracking groove 12 of the substrate 11. The laser beam reflected by the optical recording member 13 in the groove 12 returns to the same optical path via the wavelength plate A2 and is then sent to the lens 2 by the polarizing beam slitter A1.
The light is sent out to the 0-2 side, enters two photodiodes P and P2, and the amount of light is detected.

When the laser beam is aligned with the center of the groove 12 and is accurately tracked, the two photodiodes P and P
, are not the same, and the output of the differential amplifier 21 is zero. Therefore, the movable reflector 19 maintains the same angle without sending a control signal to the movable reflector control unit η. When the optical card is moved and misaligned, the laser beam comes to hit the edge of the groove 12.

FIG. 7 shows a case where the laser beam is deviated from the center position of the groove. In the figure, when the laser beam hits the edge of the groove 12, the diffraction phenomenon of light produces a diffracted light beam with a large reflection angle, most of which deviates outside the aperture of the lens. Furthermore, since the depth of the groove 12 is set to /81, a phase difference occurs between the laser beam reflected by the groove 12 and the laser beam reflected by the substrate surface S, and the reflected light is weakened due to light interference. Therefore, when the laser beam diverges to the edge of the groove 12, a difference in output occurs between the laser beam and the photodiode PI&P2, and as a result, a difference occurs in the output of the differential amplifier 21. When this signal is sent to the movable reflector control unit η and the movable reflector 19 is rotated to control the output of the differential amplifier 21 to be zero,
The laser beam is aligned with the center of the groove 12 and tracking is normal. In the above description, the movable reflecting mirror 19 was rotated, but the lens 20-1 may also be moved.

Although the tracking method has been described above using a simplified optical system, it goes without saying that other optical systems may also be used.

As described above, b-tracking control can be performed by providing tracking grooves on the substrate, but since the width of the tracking grooves is narrow, it is not possible to immediately align the optical head with the tracking grooves. , difficulties arise when considering the mechanical precision of the optical head.

[Purpose of the invention]

In order to solve the above problems, the present invention provides an optical card having an optical recording member that records thermal information on the surface or inside of the recording material by selectively irradiating laser light onto a card-shaped substrate. An object of the present invention is to provide an optical card comprising a track for guiding an optical recording and reading device and a guide section for guiding the optical recording and reading device to the track, In particular, it is an object of the present invention to provide an optical card characterized in that the guide portion has a funnel-like shape.

[Explanation of principle]

The use of an organic monolayer film containing a cyanine dye, such as a benzoindoline dye, as the optical recording member has been described above. This organic monolayer film containing cyanine dye is
There is a relationship between film thickness and reflectance as shown in the figure. This reflectance measurement is performed using a wavelength of 8
This was done using a 30nx laser beam. The organic monolayer film containing this cyanine dye has a film thickness of approximately 0.07 μm.
When m, the reflectance is maximum (40%), and as the film thickness becomes thinner, the reflectance decreases rapidly. The thickness of the film λ with the maximum reflectance corresponds to approximately 4n (here, λ””830y
Therefore, as shown in FIG. 9 (α), a shallow recess is formed in the substrate 23, and an organic monolayer film containing a cyanine dye is deposited therein. When formed so that the maximum film thickness ty1 is approximately 2/8rL and measuring the reflectance of the organic monolayer by irradiating it with a laser beam L, it is found that a recessed portion is formed as shown in FIG. 9(b). By the way, the reflectance is maximum, and the reflectance decreases in other parts.Using this difference in reflectance between the part where the recess is formed and the other parts, optical recording and reading devices can For example, tracking control for guiding the optical head to a predetermined position can be performed.

Hereinafter, the structure of the present invention will be explained with reference to the drawings. [Structure of the Invention] FIG. 10 shows an embodiment of the present invention.

In the figure, (α) is a partial plan view of the optical card of the present invention, (h) is a cross-sectional view in the X-X direction in (a), and (C
) is a cross-sectional view in the YY direction at (α). A plurality of grooves are formed in the card-shaped substrate B.

A funnel-shaped recess 27 with a rectangular cross section that is easy to form is formed at the end of this groove, and the two are connected. The maximum width W of the concave valley is, for example, about 1 mm. An organic monolayer film containing a cyanine dye, for example, a benzoindoline dye, is used as an optical recording member, and the maximum film is %rL (2=830 n
0.07 Pm). The reflectance of the organic monolayer film formed on the substrate 5 is shown in Figure 9 ψ)
Since the planar shape of the 0-concave portion γ having a gap is funnel-shaped, a funnel-shaped region with high reflectance is formed in the organic monolayer film.

This region becomes a guide portion G for guiding the optical head.

In FIG. 10(C), the thickness of the organic monolayer film is different between the part where the groove exists and the other part, and there is a difference in reflectance between the two parts. Therefore, it becomes possible to guide the optical head (due to the difference in reflectance between the two). This portion becomes a track T for guiding the optical head.

The guide part G for guiding the optical head to the track T is
The guide portion G may be formed on all the tracks, but it is also possible to form the guide portion G on only the first track. This is because the distance between the two transports is constant, and once the optical head is introduced into a track, it is easy to shift the optical head to another track based on that distance. be.

In FIG. 10, a protective layer may be formed on the organic monolayer film portion containing the dye, which is the optical recording member.

Next, a method for guiding the optical head from the guide section G of the optical card to the track T will be explained.

FIG. 11 is a plan view of the optical card of the present invention. In the figure, a region (9) of high reflectance and a region 31 of low reflectance are formed on the optical card. The area between the areas with high reflectance is composed of a guide part and a track connected to the guide part.

When a laser spot 32 for tracking is irradiated from the optical head and the optical head is allowed to advance, the laser spot 32 reaches a boundary line where the reflectance rapidly changes.

Here, when the optical head is advanced while keeping the boundary line, the optical head is guided along the track. In order to simplify the explanation, the case where there is one laser spot is shown, but it is also possible to use a plurality of laser spots.

Further, in the above explanation, the laser beam is irradiated from the protective layer side in all cases, but it goes without saying that the laser beam may be irradiated from the substrate side.

〔Effect of the invention〕

As described above, according to the present invention, the optical head can be easily guided to the trunk by forming a funnel-shaped guide portion on the optical card to guide the optical head to the track. Further, since the optical head can be aligned with the guide part within the range of mechanical precision, there is no need to provide a special structure to the optical head, and the structure of the optical head becomes simple. Furthermore, since the track can be detected quickly and reliably, reliability in recording and reproducing information is improved.

Furthermore, since the funnel-shaped recess with a rectangular cross section is easy to form on the substrate, the manufacturing yield can be increased.

[Brief explanation of the drawing]

Figures 1 (α) and (h) are a cross-sectional view and a plan view of a magnetic card, respectively, Figures 2 (a) and (h) are a cross-sectional view and a plan view of an optical card, respectively, and Figures 3 (α) and ( b) is an explanatory diagram of the operation of the optical card during recording and reproduction, FIG. 4 is an explanatory diagram showing the state in which information is recorded on the optical recording member, and FIG.
Figures (α) and (h) are a cross-sectional view and a plan view, respectively, of an optical card in which a tracking groove is provided on the substrate, Figures 6 and 7 are principle diagrams for explaining the tracking method, and Figure 8
The figure shows the relationship between the film thickness and reflectance of an organic monolayer film containing a dye, and Figures 9 (a) and (b) show an organic monolayer film when an organic amniotic film is formed in a concave part with a rectangular cross section. FIG. 10(a) is a diagram showing the relationship between reflectance and reflectance. (h) and (C) are respectively a plan view and a sectional view of an embodiment of the present invention, and FIG. 11 is a partial plan view of an optical card for explaining the tracking method. 1... Mounting paper 2... Magnetic recording material 3...
・Protective seal 4...Substrate 5...Optical recording member 6...Protection member 7...Repe' beam 8...Pit 9...Bit string
10...Direction of movement of optical head 11...Substrate
12...Tracking groove 13...
- Optical recording member 14... Protective layer 16... Laser device 17... Collimator optical system 18...
・Optical system 19...Movable reflecting mirror 20...
Lens 21...Differential amplifier 22...
Movable reflecting mirror control unit 23...Substrate 24...Organic layer coating 25...Substrate 26...Groove
27... Concavity 28... Organic layer film 2
9... Center line 30... Area with high reflectance 31.
・Low reflectance area 32... Radespot 33...
・Boundary line A1...Polarized beam sinter A2
...Radio wave plate S...Substrate surface P,,P
2...Photodiode L...Laser beam
G...Guide section T...Truck W.
...Maximum width of recess Patent applicant TDC Co., Ltd. Patent attorney Akira Yamatani 331 1st layer fz [1 (Good) (b) S+l1f1 (Good)
(B''' pG diagram (S70 fs diagram; : (Good) 1 (b)
(θ-)Sai+11'Z)

Claims (1)

[Claims] An optical recording member is formed on a card-shaped substrate and records information by thermal action on the surface or inside of the recording material by selective irradiation with laser light, and a track for guiding an optical recording and reading device. 1. An optical card comprising: a funnel-shaped guide portion provided at an end of the track for guiding the optical recording or reading device to the track.