JP3451670B2 - Method and apparatus for reading recorded information from information recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium such as a security card or an ID card, and a reading method and apparatus therefor, and in particular, there is no malfunction during reading and a defective product due to tampering can be easily discriminated. The present invention relates to an information recording medium, a recorded information reading method, and an apparatus thereof.

[0002]

2. Description of the Related Art An information recording medium shown in FIG. 6 is generally used. This information recording medium 1a is a substrate 5a.
And a thermosensitive recording layer 3a laminated thereon. Information is recorded on the thermosensitive recording layer by a writing laser beam or the like.

Bar code readers, image scanners and the like are known as reading devices for information recorded on the information recording medium 1a. These reading devices are optical reading devices, for example, a laser or a light emitting diode (LED) is adopted as a light source, and the information recording medium 1 is used.
For receiving the reflected light from a, a light receiving element having one or a plurality of photodiodes having high sensitivity to the wavelength of the irradiation laser beam is used. FIG. 7 shows an outline thereof, and an optical recording information reading device 6a includes a light emitting element 7a having a laser or a light emitting diode as a light source,
Information recording medium 1a of reference light emitted from light emitting element 7a
It is composed of a light receiving element 8a for receiving the reflected light on the surface and a transparent casing 11a for housing these. This is because when the surface of the information recording medium 1a is irradiated with the reference light from the light emitting element 7a, the amount of reflected light changes depending on the content and presence / absence of recorded information on the medium 1a. The photodiode, which is the light receiving element 8a, is intended for reading information recorded on the surface of the information recording medium 1a. However, it does not detect information in a region having a relatively wide field of view and a certain width and depth. It can be read as a macro. As a result, there is an advantage that an error-free reading can be performed even if the operation is inaccurate to some extent.

On the other hand, the information recording medium 1a is tampered with to make a fake, and the damage is increasing. It is possible to make a true / false decision by the optical recording information reading device 6a, but in many cases the decision cannot be made.
Conventionally, an information recording medium having a tampering prevention measure has been disclosed. For example, JP-A-1-188397, JP-A-1-22558 and JP-A-2-6193 may be mentioned. The "recording medium" of Japanese Patent Laid-Open No. 1-188397 has visible display information and invisible thermal marks. In addition, JP-A 1-2
No. 2558, “Article having minute pattern for preventing forgery and method for making the same”, one figure, a pattern of characters, etc. is composed of a plurality of small figures, a character pattern, etc.
The small pattern is characterized by being composed of patterns such as smaller figures and characters. Also,
The "prepaid card" of Japanese Patent Application Laid-Open No. 2-6193 forms a card by using a member whose properties change depending on the temperature of the identification portion of the card. Further, in order to further improve the tampering prevention effect, the information recording medium 1b shown in FIG. 8 has been conventionally used.

[0005]

The information recording medium 1b is composed of
The surface of the thermosensitive recording layer 3b on the substrate 5b is covered with the transparent protective layer 2b.
It is coated with. In this case, the recorded information is written on the intermediate thermosensitive recording layer 3b by laser light or the like.
It is difficult to write on the thermal recording layer 3b by a thermal head of a contact recording system, and tampering is prevented.
However, tampering with laser light etc. is possible,
Falsification cannot be determined by the conventional optical recording information reading device 6a that measures the amount of light reflected from the surface.
Further, even if the amount of reflected light of the intermediate thermosensitive recording layer 3b can be measured, in this case, there is a problem that it is not possible to discriminate tampering applied to the transparent protective layer 2b on the surface. Further, in the case of the information recording medium 1b shown in FIG. 8, heat is not sufficiently dissipated when writing is performed on the thermosensitive recording layer 3b by laser light, so that thermal distortion occurs and the surface of the transparent protective layer 2b becomes uneven. become. Therefore, there is a problem that incident light is irregularly reflected by the irregularities, which makes accurate reading difficult.

The present invention solves the above problems and is difficult to tamper with, and the tampering is automatically performed.
It is an object of the present invention to provide an information recording medium that can be easily discriminated and does not generate thermal strain during information recording, and a recorded information reading method and apparatus thereof.

[0007]

SUMMARY OF THE INVENTION The present invention, in order to achieve the above object, the surface of the uppermost layer of the transparent protective layer of the information recording medium, the reference light from the light emitting element for emitting a laser beam diagonally The light amount of the reflected light emitted from the transparent protective layer is transmitted through the transparent protective layer and reflected on the surface of the heat-sensitive recording layer again while being read by the light receiving element. It is characterized in that the information recording medium is read by another light receiving element, and whether the information recording medium is true or false is determined based on the reading result. For example, the information recording medium has a lower layer on a substrate.
From the top to the upper layer, a metal thin film layer for heat dissipation, a thermal recording layer and
And a transparent protective layer are laminated. A light emitting element that emits a laser beam as a reference light, a first light receiving element that reads the amount of reflected light reflected on the surface of the uppermost transparent protective layer of the information recording medium, and the transparent protective layer are transmitted. The second light receiving element for reading the light amount of the reflected light reflected by the heat-sensitive recording layer and emitted from the surface of the transparent protective layer, and the reading amount of both light receiving elements is compared with a predetermined amount recorded in advance, and the information is recorded. An information recording / reading device having a control device for discriminating the authenticity of a recording medium is configured. Furthermore,
By selectively using the first and second light receiving elements by the switching controller, it is possible to function as a conventional recorded information reading device.

[0008]

The laser beam of the reference light for reading is applied at an angle to the surface of the uppermost transparent protective layer. The light reflected on the surface of the transparent protective layer enters the first light receiving element, and the amount of light determined by the reflectance of the surface of the transparent protective layer is read. On the other hand, the light refracted and entered into the transparent protective layer is transmitted through the layer, reflected on the surface of the intermediate thermosensitive recording layer, transmitted through the transparent protective layer again, and is incident on the second light receiving element. The amount of light received by the second light receiving element depends on the recording information on the thermosensitive recording layer. The recorded information can be read by reading the change in the light amount. In the case of an information recording medium in which the surface of the transparent protective layer has been tampered with, the amount of incident light from the first light receiving element changes, so it is determined that the medium is not a target. Further, in the case of an information recording medium in which the thickness of the transparent protective layer is different from the predetermined one, the amount of reflection from the thermosensitive recording layer changes and the change is discriminated by the second light receiving element. Also,
In the case of an information recording medium in which information is correctly recorded on the thermosensitive recording layer, the amount of light incident on the second light receiving element changes, so that reading is possible. On the other hand, the heat generated when information is recorded on the thermosensitive recording layer by the laser beam is conducted to the metal thin film layer having high thermal conductivity and is radiated therefrom, so that the thermal distortion of the transparent protective layer or the thermosensitive recording layer is suppressed and irregular reflection due to unevenness, etc. Disappears.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an embodiment of a recorded information reading apparatus, FIG. 2 is a cross-sectional view of an embodiment of an information recording medium, and FIG. 3 is a flowchart for explaining a recorded information reading method of the present embodiment. 4 is a cross-sectional view for explaining the method of writing information on the information recording medium of the present embodiment, and FIG. 5 is a schematic configuration diagram of a recorded information reading device provided with a switching control unit.

As shown in FIG. 2, the information recording medium 1 of this embodiment is composed of four layers, the transparent protective layer 2 at the uppermost portion, the heat sensitive recording layer 3 for information recording, and the metal for heat radiation. Thin film layer 4,
Substrate 5 is laminated in close contact with each other at the bottom.

The transparent protective layer 2 is made of vinyl chloride (PVC).
And the film thickness is about 500 [μm]. Acrylic resin or polyethylene terephthalate (PET) may be used instead of vinyl chloride, and other materials may be used as long as they are transparent, have heat resistance, and have excellent mechanical strength. The film thickness is preferably in the range of 100 [μm] to 1000 [μm], and particularly preferably about 500 [μm] as described above.

The heat-sensitive recording layer 3 is a one-time type composed of a polymethine organic compound, a leuco dye, and a binder of the same quality as the transparent protective layer 2, and a rewrite in which an infrared absorber and a color former are added to these. It is composed of any of the thermosensitive coloring layers of the mold. The one-time type is a type that cannot be rewritten and is written by a laser beam having a power equal to or higher than a threshold, and the rewrite type is a type that can be rewritten, for example, about 400 [mw],
Writing with a laser beam of 300 [℃]
It is extinguished by a laser beam of [mw], 150 [° C]. The infrared absorber or color former has an absorption coefficient of 1 in the wavelength range of 780 to 830 [nm], for example.
Examples thereof include phthalocyanine dyes such as copper phthalocyanine having a strong absorption of 0 ⁴ or more, dithiol metal, complex salt dyes, naphthoquinone dyes, anthraquinone dyes, triphenylmethane dyes, aminium dyes, and diimmonium dyes. The thickness of the thermal recording layer 3 is about 1
The range of [μm] to 5 [μm] is good, and about 2 [μm] is desirable.

The metal thin film layer 4 is formed by depositing aluminum on the substrate 5 by vapor deposition. The film thickness is about 1 [μ in order to bring about the heat dissipation effect by the lateral diffusion of heat.
m] to 10 [μm] is preferable, and about 1 [μm] is particularly desirable.

Vinyl chloride is used as the substrate 5. However, those similar to those used in conventional information recording media are applicable. Further, plastic sheets such as polyethylene terephthalate, polyethylene aphthalate, polycarbonate, polyparahanic acid, paper, etc. are also used. The information recording medium 1 of the present embodiment does not require the optical transparency of the substrate, so that the substrate 5 has few restrictions on the material.

Next, the structure of an embodiment of the recorded information reading apparatus will be described with reference to FIG. Recorded information reading device 6
Is a reference light irradiation light emitting element 7 which is a light emitting element for irradiating a parallel laser beam, a first light receiving element 8, a second light emitting element 9, a control device 10, and a transparent housing for accommodating them. It consists of 11 mag. The reading is performed by bringing the bottom surface of the transparent casing 11 into contact with the surface of the transparent protective layer 2. The reference light emitting light emitting element 7 (hereinafter referred to as the light emitting element 7), the first light receiving element 8 and the second light receiving element 9 are arranged at an angle with respect to the surface of the transparent protective layer 2, and the first light receiving element 8 is provided. Is arranged at a position where reflected light on the surface of the transparent protective layer 2 can enter, and the second light receiving element 9 is located at a position where reflected light reflected from the thermal recording layer 3 and refracted on the surface of the transparent protective layer 2 enters. Will be placed. The first light receiving element 8 detects the amount of reflected light according to the recorded information written by the reflectance of the surface of the transparent protective layer 2 or tampering, and the second light receiving element 9 records the heat sensitive recording layer 3. The amount of light corresponding to the information is detected. On the other hand, the control device 10 determines whether the information recording medium 1 is true or false based on the detection results of the first and second light receiving elements 8 and 9. For example, the correct light amount of the information recording medium 1 is stored in advance and It is configured to compare the value and the detected value to determine the difference. Further, in the embodiment shown in FIG. 5, the switching control unit 12 is provided in the control device 10a. The switching control unit 12 performs switching control as to whether to use both the first and second light receiving elements 8 and 9 or to use either one of the first and second light receiving elements. 8, 9
By selecting one of the above, it is applied as having the same function as the conventional recording information reading device 6a and the like (FIG. 7). Further, since the power of the laser beam from the light emitting element 7 is sufficiently weak as compared with the power of the laser beam for writing, the recorded contents recorded in the thermal recording layer 3 will not be damaged.

Next, an outline method of writing to the information recording medium 1 of this embodiment will be described with reference to FIG. The writing laser beam 13 is emitted from a laser light source such as a laser diode (not shown), collimated by a collimator lens (not shown), and then the transparent protective layer 2 is formed by a condensing optical system including a condensing lens 14 (not shown). The light is transmitted and focused on a minute spot on the surface of the thermosensitive recording layer 3. The light energy of the laser beam with which the heat-sensitive recording layer 3 is irradiated is converted into heat energy by light-heat conversion by the infrared absorbing heat generating agent. The heat energy causes the color-forming agent contained in the heat-sensitive recording layer 3 to develop a color by a thermal reaction. This records the required information. On the other hand, most of the heat generated in the thermosensitive recording layer 3 by the irradiation of the laser beam is conducted to the side of the metal thin film layer 4 having a high thermal conductivity and diffused and radiated at the same time as the coloring reaction. Therefore, the transparent protective layer 2 is less affected by the heat generated by the laser beam irradiation, and the thermal strain thereof is suppressed.

Next, the recording information reading method of this embodiment will be described with reference to the flowchart of FIG. First, a laser beam of reference light is emitted from the light emitting element 7 (step 100). Next, the switching control unit 12 of FIG. 5 determines whether or not the switching control is performed (step 101). First or second
If only one of the light receiving elements 8 and 9 is used (in the case of yes), it is selected and the operation is performed (step 10).
2), either the first or the second light receiving element 8 or 9 is activated (steps 103 and 104). When both are used (in the case of no), the process proceeds to step 105, and the reference light from the light emitting element 7 is applied to the surface of the transparent protective layer 2 at an angle (step 105). The irradiated laser beam is separated into a component reflected on the surface of the transparent protective layer 2 (step 106) and a component refracted into the transparent protective layer 2 and transmitted through the layer (step 107). The laser beam reflected on the surface of the transparent protective layer 2 is incident on the first light receiving element 8 (step 108). Then, step 109
Then, the control device 10 determines whether or not the amount of reflected light detected by the first light receiving element 8 is equal to a predetermined amount of reflected light (step 109). If they are equal (in the case of yes), it is judged whether or not the light amount detected by the second light receiving element 9 is equal to the predetermined light amount (step 110). If they are equal, the information recording medium is genuine (step 111). If the answer in step 109 and step 110 is no, the product is a tampered product or a fake product (step 112) and is rejected (step 113). On the other hand, the laser beam transmitted through the transparent protective layer 2 is applied to the thermosensitive recording layer 3 (step 1
14) and reflect on the surface (step 115). The reflected light again passes through the transparent protective layer 2, is refracted from the transparent protective layer 2, and is incident on the second light receiving element 9 (step 11).
6). Based on the amount of light detected by the second light receiving element 9, the controller reads the information written in the information recording medium (step 117). As described above, when the surface of the transparent protective layer 2 of the information recording medium 1 has been tampered with, the thickness of the transparent protective layer 2 is out of a predetermined range, or no information is recorded on the thermosensitive recording layer 3. All things, such as those that have been tampered with, are discriminated. That is, the authenticity of the information recording medium 1 is surely determined.

In the above description, the cross-sectional shape of the information recording medium 1 is illustrated, but the shape is not limited to the illustrated one, and the configuration is not limited to the above-mentioned contents. In addition, the transparent housing 1 of the recorded information reading device 6
1, the shape of the light emitting element 7, the first and second light receiving elements 8,
The configuration and the number of 9 are not limited to those described above.

[0019]

According to the present invention, the following remarkable effects are obtained. 1) Since at least two light receiving elements are arranged and the amount of light thereof is detected and compared with a predetermined value, the presence or absence of falsification can be clearly discriminated, and true / false determination can be easily performed. 2) By arranging the metal thin film layer, the heat generated in the heat-sensitive recording layer is diffused and radiated, so that the transparent protective layer does not have irregularities due to thermal strain and does not cause irregular reflection. Therefore, it is possible to accurately detect the amount of light. 3) Since information is recorded on the intermediate thermosensitive recording layer and protected by the transparent protective layer, tampering becomes difficult. In addition, errors due to damage and dirt hardly occur. 4) It can also be used as a recording information reading device similar to the conventional one by the switching control unit. 5) The light emitting element, the light receiving element, and the control device are compactly housed in a transparent housing, which is convenient to handle.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a recorded information reading device of the present invention.

FIG. 2 is a transverse cross-sectional view showing the configuration contents of an embodiment of the information recording medium of the present invention.

FIG. 3 is a flowchart for explaining a recorded information reading method of this embodiment.

FIG. 4 is a configuration diagram for explaining a writing method for the heat-sensitive recording layer of the present embodiment.

FIG. 5 is a schematic configuration diagram of another embodiment of the recorded information reading device of the present invention.

FIG. 6 is a cross-sectional view of a conventional information recording medium.

FIG. 7 is a schematic configuration diagram of a conventional recorded information reading device.

FIG. 8 is a cross-sectional view showing another example of a conventional information recording medium.

[Explanation of symbols]

1 Information recording medium 2 Transparent protective layer 3 Thermal recording layer 4 Metal thin film layer 5 substrates 6 Recorded information reader 7 Light emitting element for reference light irradiation (light emitting element) 8 First light receiving element 9 Second light receiving element 10 Control device 10a control device 11 transparent housing 12 Switching control unit 13 Writing laser beam 14 Condensing lens

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-63-117342 (JP, A) JP-A-3-71383 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G06K 17/00 G06K 19/06-19/10 B42D 15/10 G06K 7/00-7/14

Claims (5)

(57) [Claims] 1. A reference light from a light-emitting element that emits a laser beam is obliquely applied to the surface of the uppermost transparent protective layer of an information recording medium, and the reflected light amount of the surface-reflected light of the transparent protective layer is detected by a light-receiving element. The light amount of the reflected light that has been transmitted through the transparent protective layer, reflected on the surface of the thermosensitive recording layer, and then emitted from the transparent protective layer again is read by another light receiving element, and the authenticity of the information recording medium is determined by the reading result. A method for reading recorded information, characterized by making a judgment. 2. The information recording medium is formed on a substrate from the lower layer.
Toward the upper layer, a metal thin film layer for heat dissipation, a thermal recording layer and a transparent layer.
Characterized in that it is formed by laminating a bright protective layer.
The method for reading recorded information according to claim 1, wherein 3. A light emitting element that emits laser light as reference light, a first light receiving element that reads the amount of reflected light reflected by the surface of the uppermost transparent protective layer of the information recording medium, and the transparent protective element. A second light receiving element that reads the light amount of the reflected light that has passed through the layer and is reflected by the thermosensitive recording layer and emitted from the surface of the transparent protective layer is compared with a predetermined amount that is recorded in advance. And a controller for discriminating the authenticity of the information recording medium. 4. The recording information reading device according to claim 3, wherein the control device includes a switching control unit that selects both or one of the first light receiving element and the second light receiving element. 5. The information recording medium is formed on the substrate from the lower layer.
Toward the upper layer, a metal thin film layer for heat dissipation, a thermal recording layer and a transparent layer.
Characterized in that it is formed by laminating a bright protective layer.
Read the recorded information according to claim 3 or 4.
Picking device.