JPH0922451A - Bar code recording and reproducing method, bar code recording device and bar code reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the unfair copying or reading of a bar code difficult. SOLUTION: In this method, a process in which a photosensitive layer 1 whose surface is defined as the incident plane 2 of light and the rear surface is defined as the reflection surface 3 of light is arranged so that the layer may relatively move for a light source and the light transmissivity member 8 of the refractive index which is almost equal to that of photosensitive layer 1 is arranged on the incident plane side of the photosensitive layer 1 and a process in which light beam 4 for record is irradiated from the light source at the incident angle for record which is inclined to the incident plane 2 by a fixed angle, interference fringes 5 are generated within the photosensitive layer 1 by reflecting the light beam 4 for record which is made incident from the incident plane 2 on the rear surface and the inteference fringes 5 are recorded on the photosensitive layer 1 are included. Further, a process in which light beam 4 for record is intermittently irradiated from the light source, relatively moving the photosensitive layer 1 for the light source and a bar code is recorded at the location of the photosensitive layer 1 along the moving direction of light beam 14 for record and a process in which the bar code recorded by the diffracted light beams of wavelengths of 780nm or more which can be obtained by irradiating the photosensitive layer 1 with light beam 10 for reading at an incident angle for reading is read are included.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing method and an apparatus thereof, and more particularly to a bar code recording / reproducing method and an apparatus thereof for reading by invisible light.

[0002]

2. Description of the Related Art For example, Japanese Patent Publication No. 48-6981 discloses a hologram confirmation device for confirming an object having a key hologram. This hologram confirmation device exhibits characteristics of a corresponding code between at least one point reference light source used for forming a hologram and at least one object light point, and is determined by an opposite code when m and n are positive integers. M point light sources and n photo detectors arranged at respective predetermined positions, a device for inserting a key hologram at a predetermined position with respect to the light sources and the photo detectors, and a photo detector connected to the photo detectors. And a logic circuit device which produces an output for supplying a first control signal when the n photodetectors supply individual signals at the same time when the key hologram is inserted, and a power supply for supplying power to the light source and the logic circuit device. And a device. In this hologram confirmation device, light is emitted from a plurality of light sources to a key hologram on which an interference fringe pattern is formed, and it is observed whether or not an image is formed at a predetermined point due to optical interference.

Further, Japanese Patent Laid-Open No. 6-67595 discloses a hologram in which a bar code is recorded as a hologram and a reproducing laser beam is applied to the hologram to read a bar code pattern. In this hologram, when a bar-shaped pattern composed of a plurality of parallel bars is image-formed and reproduced, only a limited part of the recording area is irradiated with a thin reproduction light beam to diffract the diffracted light at the bar-shaped pattern image formation position or A single light-receiving element receives light at a position closer to the hologram and where diffracted light beams are separated from each other, and a hologram is relatively formed in the direction across the reproduced light beam and each bar to be reproduced. The bar-shaped pattern recorded by moving is read. Furthermore, JP-A-7-6117
Japanese Patent Publication No. 3 discloses a method of recording a visible image on a recording medium that prevents forgery / alteration such as a prepaid card. Further, Japanese Patent Laid-Open No. 7-57065 discloses an invisible information recording medium which is invisible under visible light on an underlayer, and emits fluorescence upon irradiation with light of a predetermined wavelength to be visible.

[0004]

Currently, a bar code in which letters, numbers, etc. are represented by an array of lines of different thickness is POS.
Although widely used in systems and ID cards in general, conventional barcodes can be easily copied by electrophotography, etc., and are therefore easily forged and highly likely to be illegally used. However, with respect to the above problems, a method of recording / reproducing a bar code or other figures or characters by using an invisible ray has not been proposed so far.
Further, when writing on the hologram disclosed in Japanese Patent Application Laid-Open No. 6-67595, a mask having a bar-shaped opening and two lights of irradiation light to the mask and parallel reference light are used.
There is a drawback that mass production of holograms is hindered.

Therefore, an object of the present invention is to provide a bar code recording / reproducing method in which it is difficult to illegally copy or read a bar code, and an apparatus used therefor.

[0006]

A bar code recording / reproducing method according to the present invention comprises a photosensitive layer (1) having a front surface as a light incident surface (2) and a rear surface as a light reflecting surface (3) with respect to a light source. The light-transmitting member (8) having a refractive index almost equal to that of the photosensitive layer (1) on the incident surface (2) side of the photosensitive layer (1), and the light transmission. A light beam (4) for recording is emitted from a light source at an incident angle for recording which is inclined at a constant angle to the incident surface (2) of the photosensitive layer (1) through the elastic member (8) and is incident from the incident surface (2). The process of reflecting the recording light beam (4) on the back surface to generate interference fringes (5) in the photosensitive layer (1) and recording the interference fringes (5) on the photosensitive layer (1) and the light source. While moving the photosensitive layer (1) relatively, the recording light beam (4) is intermittently emitted from the light source, and is exposed along the moving direction of the recording light beam (4). Diffracted light having a wavelength of 780 nm or more obtained by recording a bar code at a predetermined position in (1) and irradiating the photosensitive layer (1) with a reading light beam (10) at a predetermined reading incident angle. And reading the bar code recorded by. The photosensitive layer (1) is made of, for example, a photosensitive resin. The light-transmissive member (8) is used to make the recording light beam (4) incident on the photosensitive layer (1) at a large incident angle, whereby the refraction angle in the photosensitive layer (1) is exposed to air. It can be greater than or equal to the critical angle of layer (1). As the light transmissive member (8), for example, a glass block is used. As a glass block for the photosensitive layer (1) with a refractive index of 1.52,
For example, borosilica glass, preferably BK7 having a refractive index of about 1.52 can be used. In the embodiment of the present invention, the critical angle of the photosensitive layer (1) to air is θ _c , the refraction angle of the recording light beam (4) in the photosensitive layer (1) is θ ₁ ,
The refraction angle of the reading light beam (10) in the photosensitive layer (1) is θ ₂ , the long wavelength end of visible light is λ _v , the wavelength of the recording light beam (4) is λ ₁ , and the reading light beam (10) If the wavelength of λ ₂ is λ ₂ , the process of recording the barcode satisfies the conditional expression (A): λ _v · cos θ ₁ <λ ₁ · cos θ _c, and the process of reading the barcode is conditional expression (B): λ ₁ · cos θ ₂ = λ ₂ · cos θ ₁ is satisfied. In another embodiment of the present invention, a photosensitive layer (1) having a front surface as a light incident surface (2) and a rear surface as a light reflecting surface (3) is arranged so as to be movable relative to a light source, Light-transmissive member (8) having a refractive index almost equal to that of the photosensitive layer (1)
Is arranged on the incident surface (2) side of the photosensitive layer (1), and a mask (9) having a slit group in a direction orthogonal to the moving direction of the recording light beam (4) is used to remove the light transmitting member (8). Cover the entrance surface (8a). Next, a light beam for recording (4) is emitted from a light source through a light transmissive member (8) to a light incident surface (2) of the photosensitive layer (1) at a light incident angle for recording which is inclined by a certain angle, and the light incident surface (2) is irradiated. The recording light beam (4) incident from 2) is reflected on the back surface to generate interference fringes (5) in the photosensitive layer (1), and the interference fringes (5) are recorded on the photosensitive layer (1). Then, while moving the photosensitive layer (1) relative to the light source, the recording light beam (4) is continuously emitted from the light source, and the light is exposed along the moving direction of the recording light beam (4). Record the bar code in place on layer (1).

The bar code recording apparatus according to the present invention has a photosensitive layer (1) having a light incident surface (2) and a rear surface serving as a light reflecting surface (3) and a refraction which is almost equal to that of the photosensitive layer (1). And a light transmissive member (8) disposed on the incident surface (2) side of the photosensitive layer (1) and inclined at a constant angle with respect to the photosensitive layer (1) through the light transmissive member (8). With the light source for irradiating the recording light beam (4) at the recording incident angle and the light transmissive member (8) arranged on the incident surface (2) side of the photosensitive layer (1), the photosensitive layer (1) And a support body (6) for supporting the light source so as to be movable relative to the light source. The photosensitive layer (1) is irradiated with the recording light beam (4) from the light source through the light transmissive member (8), and the recording light beam (4) incident from the incident surface (2) is reflected on the back surface. Interference fringes (5) are generated in the photosensitive layer (1), the interference fringes (5) are recorded on the photosensitive layer (1), and further the photosensitive layer (1) is moved relative to the light source, The recording light beam (4) is emitted intermittently from the light source, and the recording light beam (4) is emitted.
A bar code is recorded at a predetermined position on the photosensitive layer (1) along the moving direction of. Further, in another barcode recording apparatus according to the present invention, the photosensitive layer (1) having a front surface as a light incident surface (2) and a rear surface as a light reflecting surface (3) is substantially equal to the photosensitive layer (1). A light transmissive member (8) having a refractive index and arranged on the incident surface (2) side of the photosensitive layer (1), and a slit group in a direction orthogonal to the moving direction of the recording light beam (4). And the mask (9) covering the incident surface (8a) of the light transmissive member (8) and the incident angle for recording which is inclined at a constant angle with respect to the photosensitive layer (1) through the light transmissive member (8). With the light source for irradiating the recording light beam (4) and the light transmissive member (8) arranged on the incident surface (2) side of the photosensitive layer (1), the photosensitive layer (1)
And a support body (6) for supporting the light source so as to be movable relative to the light source. The photosensitive layer (1) is irradiated with the recording light beam (4) from the light source through the light transmissive member (8), and the recording light beam (4) incident from the incident surface (2) is reflected on the back surface. Interference fringes (5) are generated in the photosensitive layer (1), the interference fringes (5) are recorded on the photosensitive layer (1), and further the photosensitive layer (1) is moved relative to the light source, A recording light beam (4) is emitted from a light source, and a bar code is recorded at a predetermined position on the photosensitive layer (1) along the moving direction of the recording light beam (4).

The bar code reproducing apparatus according to the present invention comprises a light source (11) for irradiating the photosensitive layer (1) with a reading light beam (10) at a predetermined reading incident angle, and a reading light beam (1).
Sensor (14) for detecting diffracted light having a wavelength of 780 nm or more obtained by irradiating the photosensitive layer (1) with (0). The bar code recorded on the photosensitive layer (1) is read by detecting the diffracted light obtained by irradiating the photosensitive layer (1) with the reading light beam (10). Further, the light beam (10) for reading, which is arranged between the light source (11) and the photosensitive layer (1) and is emitted from the light source (11) to the photosensitive layer (1), is transmitted through the photosensitive layer (1). ) May be provided with a half mirror (15) for reflecting the diffracted light.

[0009]

[Operation] By appropriately selecting the incident angle and wavelength of the recording light beam (4) during hologram recording, even if the wavelength of the recording light beam (4) is in the visible region, the reading light beam (10 The wavelength of (1) can be changed to the infrared region of 780 nm or more, which makes it difficult to illegally copy or read the barcode.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a bar code recording / reproducing method according to the present invention will be described below with reference to FIGS.

As shown in FIG. 1, in the barcode recording / reproducing method according to the present invention, a photosensitive layer 1 having a front surface as a light incident surface 2 and a rear surface as a light reflecting surface 3 is prepared. Photosensitive layer 1
Is a wet photopolymer “DMP12” manufactured by Polaroid.
A photosensitive resin such as 8 "(trade name) can be used. Photopolymer is a matrix resin with a polymerizable monomer, a polymerization initiator,
This is a dispersion of a photosensitizer, and when a standing wave due to interference is generated, the polymerization proceeds only in the antinode part of the standing wave to increase the refractive index. As the photopolymer, it is possible to use polyvinylcarbazole in which an acrylic monomer is dispersed.

The photosensitive layer 1 is arranged so as to be movable relative to a light source (not shown). Further, as shown in FIG. 1, the glass block 8 serving as a light-transmissive member has a photosensitive layer 1
Is arranged on the incident surface 2 side. Next, the incident surface 2 of the photosensitive layer 1 is intermittently irradiated with the recording light beam 4 through the glass block 8 at an incident angle inclined by a certain angle.
The recording light beam 4 that has entered from is reflected by the reflection surface 3 on the back surface to cause interference in the photosensitive layer 1. The recording light beam 4 is, for example, an argon laser having a wavelength of λ = 448 nm (nanometer). When the recording light beam 4 with which the photosensitive layer 1 is irradiated is totally reflected by the reflecting surface 3, the photosensitive layer 1
Inside, two wavefronts of incident light and reflected light overlap and cause interference. Interference fringes 5 due to this light interference are recorded on the photosensitive layer 1. In this way, by exposing with a single light source, the standing wave is generated by the interference between the incident light and the light that is transmitted through the photosensitive layer and reflected on the back surface, and the method of recording interference fringes in the photosensitive layer is Denisk It is called an exposure method, and the exposure arrangement of the photosensitive layer at this time is called Denisk arrangement. The Denishk exposure method is known as one of the methods for obtaining a hologram. In addition, when obtaining a hologram of near infrared diffraction,
Since the incident angle of the recording light beam is large, the recording light beam incident on the photosensitive layer is totally reflected by the reflecting surface. Therefore, it is not necessary to apply a light-reflecting coating on the back surface of the photosensitive layer.

Subsequently, when the recording light beam 4 is intermittently irradiated while moving the photosensitive layer 1 relatively to the light source, the interference fringes 5 generated by the recording light beam 4 cause
The photosensitive layer 1 is intermittently exposed to light along the moving direction, and a bar code is recorded at a predetermined position on the photosensitive layer 1 along the moving direction of the photosensitive layer 1. In this case, a long code is recorded when irradiated for a long time, and a short code is recorded when irradiated for a short time. When a wet photopolymer is used for the photosensitive layer, the difference in refractive index Δn between the high-refractive index portion and the low-refractive index portion is increased by recording the barcode and then swelling / shrinking treatment to improve the diffraction efficiency. On the other hand, when a dry photopolymer is used for the photosensitive layer, heat treatment is applied instead of the swelling / shrinking treatment performed in the case of the wet photopolymer. By the heat treatment, unreacted monomers migrate to the high refractive index portion to further promote the polymerization, so that the refractive index difference Δn is expanded and the diffraction efficiency is improved.

As shown in FIG. 2, when the bar code obtained in the above manner is read, the photosensitive layer 1 is irradiated with the reading light beam 10 at a predetermined reading incident angle ψ. The bar code recorded by the diffracted light having a wavelength of 780 nm or more obtained at this time can be read. Light beam for reading 1
0 diffracts light having a wavelength corresponding to the interval of the interference fringes 5. The critical angle of the photosensitive layer 1 with respect to air is θ _c , and the recording light beam 4 is
Is θ ₁ , the angle of refraction of the reading light beam in the photosensitive layer 1 is θ ₂ , and the long wavelength end of visible light is λ 2.
_{When v} (= 780 nm), the wavelength of the recording light beam 4 is λ ₁ , and the wavelength of the reading light beam 10 is λ ₂ , the barcode recording process satisfies the conditional expression (A). Conditional expression (A): λ _v · cos θ ₁ <λ ₁ · cos θ _{c Further} , the process of reading the barcode satisfies the conditional expression (B). Conditional expression (B): λ ₁ · cos θ ₂ = λ ₂ · cos θ ₁ For example, when recording is carried out at θ ₁ = 65 ° using an argon laser of λ ₁ = 448.0 nm, from the conditional expression (B) It suffices to read with a light beam of λ ₂ = 850 nm at θ ₂ = 36.7 °. In this case, the refractive index of the photosensitive layer is n =
At 1.52, the incident angle of the reading light beam 10 is ψ =
It becomes 65.3 °.

At this time, the wavelength λ ₂ of the reading light beam 10
Is out of the visible light range (wavelength 380 to 780 nm), the diffracted light that is the reproduction light is invisible. As described above, when the incident angle of the incident light at the time of recording the barcode is increased and the read angle is decreased, the pitch of the interference fringes 5 apparently increases, and the wavelength of the writing light is in the visible region. It becomes possible to change the wavelength of the reading light to the infrared region. On the contrary, when reading from an angle larger than the incident angle of the incident light at the time of barcode recording, the apparent interference fringes 5
Since there is a possibility that visible light may be emitted because the pitch of No. 1 is reduced, it is preferable to make the incident angle at the time of barcode recording as large as possible because the visible region can be reduced. As described above, by appropriately selecting the incident angle and wavelength of the recording light beam 4 at the time of barcode recording, the recording light beam 4 can be recorded.
Even if the wavelength is in the visible region, the wavelength of the reading light beam 10 can be changed to the infrared region of 780 nm or more, which makes it difficult to copy or read the barcode.

A method of deriving the conditional expressions (A) and (B) will be described. When a recording light beam is incident from the light source of wavelength λ _{1 at} a refraction angle θ ₁ in the photosensitive layer and interferes with the reflected light from the back surface in a Denisk arrangement to record interference fringes inside the photosensitive layer, the interference fringes formed The interval Λ _{1 of} is expressed by the following equation. Λ ₁ = λ ₁ / (2n · cos θ ₁ ). . . . . . (1) Generally, when a light beam is incident at a refraction angle ξ in the photosensitive layer, the diffraction wavelength λ that satisfies the black condition is represented by the following equation. λ = 2nΛ ₁ · cos ξ. . . . . . . . . (2) Since 2nΛ ₁ = λ ₁ / cos θ ₁ from (1), λ = λ ₁ · cos ξ / cos θ ₁ .. . . . . . . (3) From (3), the diffraction wavelength λ becomes a monotonically decreasing function as shown in FIG. 3 with respect to the refraction angle ξ. When the reading light beam is incident on the photosensitive layer from the air, the incident angle ψ is determined in the following range. 0 ≦ ψ <90 °. . . . . . . . . . . (4) In contrast to (4), when the critical angle of the photosensitive layer with respect to air is θ _c , the range of the refraction angle ξ of the reading light beam is as follows. 0 ≦ ξ <θ _c . . . . . . . . . . . . (5) Therefore, if the diffraction wavelength when ξ = θ _c is λ _c , then λ _c
Is the minimum wavelength that can be diffracted. In (3), λ =
If λ _c , then λ _c = λ ₁ · cos θ _c / cos θ ₁ . . . . . . (6) Here, if λ _c is made larger than the long wavelength end λ _v (780 nm) of visible light, visible light is not diffracted by the photosensitive layer. That is, λ _c > λ _v . . . . . . . . . . . . . . (7) By substituting (6) into (7) and transforming, an exposure conditional expression is obtained. λ _v · cos θ ₁ <λ ₁ · cos θ _c . . . . . . (A) In order to make near-infrared light (wavelength λ ₂ ) incident on the photosensitive layer and diffract it for reproduction, the following reproducing condition expression should be satisfied from (3). Note that θ ₂ is a refraction angle of incident light to the photosensitive layer. λ ₂ = λ ₁ · cos θ ₂ / cos θ ₁ ∴λ ₁ · cos θ ₂ = λ ₂ · cos θ ₁ . . . . (B) At this time, the incident angle ψ ₂ on the photosensitive layer is obtained from Snell's law as follows. sin ψ ₂ = n · sin θ ₂ ∴ ψ ₂ = sin ⁻¹ (n · sin θ ₂ ). . . . . (8)

The present invention utilizes a volume phase hologram in which a plurality of transparent interference fringes having different refractive indexes are recorded in a multilayer structure on a photosensitive layer having a thickness of about several μm. The high refractive index part of the photosensitive layer where the interference fringes are recorded is the bright part,
The low refractive index portions are called dark portions. In FIGS. 1 and 2, the interference fringes are shown by black lines for convenience, but in reality
Since the dark areas are transparent, they are not visible as light and dark stripes. The volume phase hologram is superior in diffraction efficiency to a surface hologram having an uneven surface and an amplitude hologram using a silver salt photosensitive material.

In the bar code recording apparatus of the present invention shown in FIG. 4, the entrance surface 8a of the glass block 8 is covered with a mask 9 having a slit group in a direction orthogonal to the moving direction of the recording light beam 4. When recording a barcode, a recording light beam 4 is emitted from a light source at an incident angle for recording which is inclined to the incident surface 2 of the photosensitive layer 1 by a certain angle, and the recording light beam 4 incident from the incident surface 2 is reflected on the back surface. Then, interference fringes 5 are generated in the photosensitive layer 1, and the interference fringes 5 are recorded on the photosensitive layer 1. Then, while moving the photosensitive layer 1 relative to the light source,
The recording light beam 4 is continuously emitted from the light source, and the mask 9
Thus, a bar code is recorded at a predetermined position on the photosensitive layer 1.

The glass block 8 is used to make the recording light beam 4 incident on the photosensitive layer 1 at a large incident angle.
That is, by using the glass block 8, the photosensitive layer 1
The refraction angle therein can be equal to or greater than the critical angle of the photosensitive layer 1 with respect to air. Further, by setting the incident surface 8a of the glass block 8 on which the recording light beam 4 is incident to be substantially perpendicular to the recording light beam 4, the reflection on the incident surface 8a can be reduced and the exposure efficiency is improved. Refractive index 1.5
When two photosensitive layers are used, BK7 is used as the glass block, for example. BK7 is a kind of borosilicate crown glass and has a refractive index of about 1.52. The transparent substrate 6 is used as a support for supporting the photosensitive layer 1 during exposure,
It is possible to make a product as it is attached to the photosensitive layer 1. Further, the photosensitive layer 1 may be peeled from the transparent substrate 6 and attached to another substrate to obtain a product. The matching liquid 7 is intended to suppress reflection at the interface and to bring the transparent substrate 6 and the glass block 8 into close contact with each other. For example, xylene is used as the matching liquid. If the refractive index of the photosensitive layer 1, the transparent substrate 6, the matching liquid 7 and the glass block 8 is greatly different, the reflection at each interface becomes large, and the incident energy of the recording light beam 4 on the photosensitive layer 1 is reduced. The interface reflection light may form an unnecessary diffraction grating. For this reason, it is not necessary for these refractive indices to be completely the same, but it is preferable to make them as close as possible.

The position of the photosensitive layer 1 with respect to the transparent substrate 6 may be either the irradiation side of the recording light beam 4 or the opposite side. However, when the matching liquid 7 directly contacts the photosensitive layer 1, problems such as swelling and peeling from the transparent substrate 6 are likely to occur. Therefore, it is preferable that the photosensitive layer 1 is arranged on the side opposite to the irradiation side of the recording light beam 4, that is, in contact with the air. Further, since the photosensitive layer 1 is generally anaerobic polymerizable, the surface of the photosensitive layer 1 is often coated or laminated with a polyester film to form an oxygen barrier. However, a plastic film such as a polyester film may have optical anisotropy such as birefringence since it is biaxially stretched during extrusion molding from a die, so that unnecessary interference may occur when recording a barcode. May form streaks. Therefore, in order not to disturb the optical path, it is better to arrange the photosensitive layer 1 on the side in contact with air.

The bar code can be read using the bar code reproducing device shown in FIG. In FIG. 5, 11 is a semiconductor laser oscillator, 12 is an objective lens,
Reference numeral 13 is a collimation lens, and 14 is a CCD sensor. In the above embodiment, an example in which an argon laser having a wavelength of 448 nm is used, but λ ₁ = 632.8n.
A helium-neon laser with a wavelength of m can be used. Θ using this helium-neon laser
When recording at ₁ = 55 °, from the conditional expression (B), λ ₂
It suffices to read with a light beam of = 1100 nm at θ ₂ = 4.4 °. In this case, the refractive index of the photosensitive layer is n = 1.5.
When 2, the incident angle of the reading light beam 10 is ψ = 6.7.
°. Thus, the incident angle ψ of the reading light beam 10
When is extremely small, a reproducing device having a half mirror 15 as shown in FIG. 6 can be used. Also, 6
A helium-krypton laser device that produces an 80 nm red laser can also be used. Further, the same effect can be obtained by using a light source having a wavelength of the recording light beam in the infrared region (780 nm) such as a titanium sapphire laser.

The embodiment of the present invention is not limited to the above-mentioned embodiment, but can be modified. For example, the interference pitch can be changed by controlling the incident angle of the recording light beam. The negative of the mask having the slit group can be formed by exposing on a dry film using liquid crystal.

[0023]

According to the present invention, since it is difficult to copy or read the bar code, it becomes impossible to copy the bar code to prevent forgery and improve the antitheft effect.

[Brief description of drawings]

FIG. 1 is a sectional view showing a mechanism of a barcode recording process according to the present invention.

FIG. 2 is a sectional view showing a mechanism of a barcode reading process according to the present invention.

FIG. 3 is a graph showing the relationship between the refraction angle ξ and the diffraction wavelength λ.

FIG. 4 is a sectional view showing the outline of a barcode recording apparatus according to the present invention.

FIG. 5 is a plan view showing the outline of a bar code reproducing apparatus according to the present invention.

FIG. 6 is a plan view showing the outline of another barcode reproducing apparatus according to the present invention.

[Explanation of symbols]

1. . Photosensitive layer, 2. . Plane of incidence, 3. . Reflective surface,
4. . Recording light beam, 5. . Interference fringes, 6. . Transparent substrate (support), 8. . Glass block (light transmissive member), 8a. . 8. Incident surface of glass block (light transmissive member), . Mask, 10. . Light beam for reading

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G06K 1/12 G06K 1/12 G 7/12 7429-5B 7/12 B 19/10 19/00 AR (72) Inventor Masato Shinoda 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Hideichi Ikui 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd.

Claims (10)

[Claims] 1. A photosensitive layer (1) having a front surface as a light incident surface (2) and a rear surface as a light reflecting surface (3) is arranged so as to be movable relative to a light source. ) Is disposed on the incident surface (2) side of the photosensitive layer (1), and a light transmissive member (8) having a refractive index substantially equal to Incident surface (2)
In the photosensitive layer (1), the recording light beam (4) is irradiated from the light source at a recording incidence angle inclined by a certain angle, and the recording light beam (4) incident from the incidence surface (2) is reflected on the back surface. The interference fringe (5) is generated on the photosensitive layer (1) and the interference fringe (5) is recorded on the photosensitive layer (1), and the photosensitive layer (1) is moved relative to the light source.
A process of intermittently irradiating a recording light beam (4) from a light source to record a bar code at a predetermined position of the photosensitive layer (1) along the moving direction of the recording light beam (4), and a photosensitive layer ( And (1) a step of reading a bar code recorded by diffracted light having a wavelength of 780 nm or more obtained by irradiating the reading light beam (10) at a predetermined reading incident angle. How to play. 2. The critical angle of the photosensitive layer (1) with respect to air is θ _c , the refraction angle of the recording light beam (4) at the photosensitive layer (1) is θ ₁ , and the photosensitive layer of the reading light beam (10) ( The refraction angle in 1) is θ ₂ , the long wavelength end of visible light is λ _v , the wavelength of the recording light beam (4) is λ ₁ , and the wavelength of the reading light beam (10) is λ _2.
Then, in the process of recording the barcode, the conditional expression (A): λ _v · cos θ ₁ <λ ₁ · cos θ _c is satisfied, and in the process of reading the barcode, the conditional expression (B): λ ₁ · cos θ ₂ = The barcode recording / reproducing method according to claim ₁ , wherein λ ₂ · cos θ ₁ is satisfied. 3. The bar code recording / reproducing method according to claim 1, wherein the photosensitive layer (1) is made of a photosensitive resin. 4. A photosensitive layer (1) having a front surface as a light incident surface (2) and a rear surface as a light reflecting surface (3) is arranged so as to be movable relative to a light source. ) Is disposed on the incident surface (2) side of the photosensitive layer (1), and a slit group is formed in a direction orthogonal to the moving direction of the recording light beam (4). Masks with (9)
Process of covering the incident surface (8a) of the light transmissive member (8) with the light transmissive member (8) and the incident surface (2) of the photosensitive layer (1) through the light transmissive member (8).
In the photosensitive layer (1), the recording light beam (4) is irradiated from the light source at a recording incidence angle inclined by a certain angle, and the recording light beam (4) incident from the incidence surface (2) is reflected on the back surface. The interference fringe (5) is generated on the photosensitive layer (1) and the interference fringe (5) is recorded on the photosensitive layer (1), and the photosensitive layer (1) is moved relative to the light source.
A process of irradiating a recording light beam (4) from a light source and recording a barcode at a predetermined position on the photosensitive layer (1) along the moving direction of the recording light beam (4), and And a step of reading a bar code recorded by diffracted light having a wavelength of 780 nm or more obtained by irradiating a reading light beam (10) at a predetermined reading incident angle. 5. The critical angle of the photosensitive layer (1) to air is θ _c , the refraction angle of the recording light beam (4) in the photosensitive layer (1) is θ ₁ , and the photosensitive layer of the reading light beam (10) ( The refraction angle in 1) is θ ₂ , the long wavelength end of visible light is λ _v , the wavelength of the recording light beam (4) is λ ₁ , and the wavelength of the reading light beam (10) is λ _2.
Then, in the process of recording the barcode, the conditional expression (A): λ _v · cos θ ₁ <λ ₁ · cos θ _c is satisfied, and in the process of reading the barcode, the conditional expression (B): λ ₁ · cos θ ₂ = The barcode recording / reproducing method according to claim 4, wherein λ ₂ · cos θ ₁ is satisfied. 6. The bar code recording / reproducing method according to claim 4, wherein the photosensitive layer (1) is made of a photosensitive resin. 7. A photosensitive layer (1) having a front surface as a light incident surface (2) and a rear surface as a light reflecting surface (3); and a photosensitive layer having a refractive index substantially equal to that of the photosensitive layer (1). (1)
Of the light-transmitting member (8) disposed on the incident surface (2) side of the recording light beam and the recording light beam at a recording incident angle inclined by a certain angle with respect to the photosensitive layer (1) through the light-transmitting member (8). The photosensitive layer (1) can be moved relative to the light source with the light source for irradiating (4) and the light transmissive member (8) arranged on the incident surface (2) side of the photosensitive layer (1). A recording medium is provided with a support (6) for supporting the recording layer, and the photosensitive layer (1) is irradiated with a recording light beam (4) from a light source through a light transmissive member (8) and is incident from an incident surface (2). The light beam (4) for reflection is reflected on the back surface to generate interference fringes (5) in the photosensitive layer (1), the interference fringes (5) are recorded on the photosensitive layer (1), and the light is further exposed to the light source. While moving the layer (1) relatively, a recording light beam (4) is intermittently emitted from a light source, and a predetermined position of the photosensitive layer (1) is provided along the moving direction of the recording light beam (4). In barco Bar code printing apparatus characterized by recording a. 8. A photosensitive layer (1) having a front surface as a light incident surface (2) and a rear surface as a light reflecting surface (3); and a photosensitive layer having a refractive index substantially equal to that of the photosensitive layer (1). (1)
Of the light-transmissive member (8) arranged on the incident surface (2) side of the light-transmissive member and the slit group in the direction orthogonal to the moving direction of the recording light beam (4) and incident on the light-transmissive member (8). A mask (9) for covering the surface (8a) and a light source for irradiating a recording light beam (4) at a recording incident angle inclined by a certain angle with respect to the photosensitive layer (1) through a light transmissive member (8). And a support (6) for movably supporting the photosensitive layer (1) with respect to the light source in a state where the light transmissive member (8) is arranged on the incident surface (2) side of the photosensitive layer (1). ) And irradiating a recording light beam (4) from the light source to the photosensitive layer (1) through the light transmissive member (8), the recording light beam (4) incident from the incident surface (2) is Reflect on the back surface to generate interference fringes (5) in the photosensitive layer (1), record the interference fringes (5) on the photosensitive layer (1), and further, place the photosensitive layer (1) relative to the light source. Do not move to And a recording light beam (4) emitted from a light source, and a barcode is recorded at a predetermined position on the photosensitive layer (1) along the moving direction of the recording light beam (4). Recording device. 9. A light source (11) for irradiating the photosensitive layer (1) with a reading light beam (10) at a predetermined incident angle for reading, and irradiating the photosensitive layer (1) with the reading light beam (10). The sensor (14) for detecting diffracted light having a wavelength of 780 nm or more obtained by irradiating the photosensitive layer (1) with the reading light beam (10) to detect the diffracted light A bar code reproducing device characterized by reading a bar code recorded in a layer (1). 10. A light beam for reading (10) which is arranged between a light source (11) and a photosensitive layer (1) and which is irradiated from the light source (11) to the photosensitive layer (1) is transmitted and is also exposed. Half mirror (1 that reflects the diffracted light obtained from the layer (1)
The barcode reproducing apparatus according to claim 9, further comprising 5).