JP2001319380A - Optical disk with rfid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speedily inform a user of the contents of the information recorded on an optical disk without reproducing them. SOLUTION: This optical disk has a reflection film 12 formed on the surface in the vicinity of the center hole 11a of a disk substrate 11 and is constituted so that the information can be stored as a pit 12c between a read-in part 12a of the film 12 and a read-out part 12b. A RFID 13 constituted of a coil 14 formed by winding around the vicinity of the hole 11a by one or more times and a IC chip 16 connected to both ends of the coil 14 is arranged on the surface of the film 12 between the edge of the hole 11a and the part 12a. A radial notch 17, which is extended from the inner edge of the film 12 and crosses the coil 14 and the tip of which is separated from the outer edge of the coil 14 by 2.5 mm or longer, is formed on the film 12. An electrically conductive film 18, which shows 0.25 Ω or smaller electric resistance value when the width and length of the film 18 are 1 cm, is formed, directly or while interposing a protection film, on the film 12 between the circle 12d coming into contact with the tip of the notch 17 and the part 12b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk which is a high-density information recording medium using a semiconductor laser. More specifically, the present invention relates to an optical disk provided with an RFID.

[0002]

2. Description of the Related Art Optical discs are read-only optical discs for exclusively reproducing previously recorded audio and video, write-once optical discs for storing data in corporate R & D and programs in system development, and rewritable optical discs. Optical discs. Since data and programs in research and development recorded on optical discs in companies are valuable, taking in and out of storage locations of optical discs on which such data or programs are recorded is strictly controlled. A desired optical disk is selected by visually checking the title or the like printed on the label attached to the optical disk.

[0003]

However, when a relatively large number of optical discs are stored in the same place, the titles and the like printed on the labels of the individual optical discs are relatively similar. There is a problem that a desired optical disk cannot be immediately selected only by its title or the like. That is, when the approximate title is printed on a plurality of optical discs, the plurality of optical discs are first selected and inserted into the reproducing apparatus, and the actually stored information must be read out individually to obtain a desired optical disc. There is a problem that it is not possible to determine whether or not.

In order to solve this problem, it is conceivable to preliminarily write a sufficient amount of content on the label so that the optical disc can be identified. However, there is a limit in the space for writing the label, and the storage content of the optical disc is limited. In the case of rewriting, there is an annoyance that the label must be replaced and newly described. Further, if the optical disk can be identified without writing anything on the label, it is possible to suppress theft caused by the identification of the optical disk by visual recognition. SUMMARY OF THE INVENTION An object of the present invention is to provide an RFID-equipped optical disk that allows the user to quickly know the information content recorded on the optical disk without actually reproducing the information. Another object of the present invention is to provide an RFID-equipped optical disk capable of developing various potential uses using the data of the optical disk and the data of the RFID.

[0005]

The invention according to claim 1 is
As shown in FIG. 1, a reflective film 12 is formed on a surface of a disk substrate 11 having a central hole 11a around the central hole 11a, and information is pitted between a lead-in portion 12a and a lead-out portion 12b of the reflective film 12. This is an improvement of an optical disk configured to be able to store as 12c. Its characteristic configuration is that a coil 14 is formed by winding one or more times around the center hole 11a and an IC connected to both ends of the coil 14.
The RFID 13 constituted by the chip 16 and the center hole 1
1a is provided on the surface of the reflective film 12 between the edge of the hole and the lead-in portion 12a. The notch 17 is formed in the reflection film 12.

According to the first aspect of the present invention, the RFID
By providing the (Radio Frequency Identification) 13 directly on the optical disk 10, the information content on the optical disk 10 can be quickly known in relation to another device that emits information content or the like by exchanging information with the RFID. The reflection film 12 of the optical disk has conductivity having a corresponding resistance. A voltage is applied to the reflection film 12 by mutual induction of the current flowing through the coil 14, the current flows, and energy is lost. This energy loss is RFID
13 lowers the Q value and weakens the resonance intensity. On the other hand, by forming a notch 17 in the reflective film 12 and setting the distance between the notch 17 and the outer edge of the coil 14 to be 2.5 mm or more, the reflective film 12 which affects the Q value of the coil 14 is formed.
, And the Q value is prevented from lowering.

The invention according to claim 2 is the invention according to claim 1, wherein the reflection film 12 between the lead-out portion 12b and a circle 12d concentric with the center hole 11a and in contact with the tip of the notch 17 is provided. This is an optical disc with RFID in which the conductive film 18 is formed directly or via a protective film. A circle 12 concentric with the center hole 11a and in contact with the tip of the notch 17 of the reflection film 12.
The portion between d and the lead-out portion 12b exerts an influence on the RFID 13 as a circuit having a small electric resistance. Conductive film 1
8, a current flows due to mutual induction. In the case of a high frequency, the current flowing due to the effect of the self-inductance of the conductive film 18 does not increase even if the resistance of the conductive film 18 is low. Will be higher. Therefore, in the optical disc with RFID according to the second aspect, the Q value can be increased by providing the conductive film 18.

The invention according to claim 3 is the invention according to claim 2, wherein the conductive film 18 has a width of 1 cm and a length of 1 cm.
cm, the electrical resistance of the conductive film 18 is 0.25 Ω or less. In the optical disk with RFID according to the third aspect, since the electric resistance value of the conductive film 18 is 0.25Ω or less, a decrease in the Q value due to the loss due to the conductive film 18 can be reduced. Although the self-inductance decreases due to the effect of the current flowing through the conductive film 18, the self-inductance can be adjusted by increasing the number of turns of the coil so as to have a predetermined inductance under the influence of the conductive film 18. .

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an optical disk with RFID according to the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 and 2, the optical disk 10 includes a disk substrate 11 having a central hole 11a and a reflective film 12 made of an aluminum vapor-deposited film formed directly on the surface of the disk substrate 11 around the central hole 11a. Prepare. The optical disk 10 is a so-called card-type compact disk, and stores data in corporate R & D and programs in system development. The optical disk 10 is stored in a company development room after data or programs are stored. Information composed of data or a program includes phase pits 12c composed of irregularities between a lead-in portion 12a near the center hole 11a of the reflective film 12 provided on the disk substrate 11 and a lead-out portion 12b near the outer peripheral edge of the disk substrate 11. And this information is reproduced by analyzing a laser beam emitted from the back side of the disk substrate 11. The optical disk is not a compact disk,
DVD-RAM (DigitalVersatile Disc-Random Acces)
s Memory), DVD-R (DVD-Recordable), DVD-
RW (DVD-ReWritable) CD-R (Compact Disc-Recor)
writeable or rewritable optical discs such as dable) and CD-RW (Compact Disc-ReWritable).

The edge of the center hole 11a and the lead-in portion 12a
RFID (Radio Frequent)
ncy Identification) 13 is provided. This RFID
Reference numeral 13 denotes a coil 14 formed by winding one or more times around the center hole 11a of the disk substrate 11, and IC chips 16 connected to both ends of the coil 14. The coil 14 and the IC chip 16 in this embodiment are provided on the surface of the reflection film 12. Specifically, the coil 14 is formed in a spiral shape by removing unnecessary portions from a conductive material such as an aluminum foil or a copper foil by an etching method, a punching method, or the like, and forms a spiral between the inner edge of the coil 14 and the hole edge of the center hole 11a. The interval is at least 0.1 mm, and the interval between the outer edge of the coil 14 and the lead-in portion 12a is at least 2.5 mm. The IC chip 16 is connected to both ends of the coil 14 with the insulating film (not shown) interposed therebetween and the reflection film 1
2

A notch 17 is formed in the reflection film 12 in the radial direction. The notch 17 extends from the inner edge of the reflection film 12 to the coil 1.
4 and cut out from the outer edge of the coil 14
7 is formed so that the distance A to the front end is 2.5 mm or more. The notch 17 in this embodiment is formed by cutting the reflection film 12 on the side opposite to the position where the IC chip 16 is provided to a width of 0.1 mm from the center hole 11a. The notch 17 is for preventing the generation of a low-voltage eddy current in the reflective film 12, and therefore, the width thereof may be extremely small. Even if the notch 17 of 1 μm is formed, it is sufficient. The notch 17
May be formed at the same time when aluminum as the reflective film 12 is deposited, or may be formed at one location or at two or more locations.

The reflection film 1 between the circle 12d concentric with the center hole 11a contacting the tip of the notch 17 and the lead-out portion 12b
2, a conductive film 18 is formed. Although the conductive film 18 in this embodiment is directly attached to the reflective film 12 with an adhesive layer (not shown) and no protective film is provided, a protective film (not shown) may be formed on the conductive film 18. Further, a protective film (not shown) may be formed on the reflective film 12 and a conductive film may be formed on the protective film. Further, the conductive film 18 may be attached by vapor deposition without using the adhesive layer, or a paint containing conductive flakes may be applied. In the case of applying a paint containing conductive flakes, the conductive film can also serve as a protective film. When the conductive film 18 is formed of an aluminum foil, a copper foil, a silver film, or the like,
The thickness is preferably in the range of 5 μm to 30 μm, and the preferable thickness in the case of a vapor-deposited film is 0.05 μm to 0.1 μm.
The range is 50 μm. In the case of a paint, its thickness is selected so that the electrical resistance value when the width is 1 cm and the length is 1 cm is 0.25Ω or less according to the specific resistance value.

As shown in FIG. 3, the IC chip 16 includes a power supply circuit 16a, a radio frequency (RF) circuit 16b, a modulation circuit 16c, a demodulation circuit 16d, a CPU 16e, and a memory for storing information unique to the optical disk 10 connected thereto. 16f
Having. The power supply circuit 16a includes a capacitor (not shown), and the capacitor forms a resonance circuit with the coil 14. This capacitor is charged with electric power generated by electromagnetic induction when the coil 14 receives a radio wave having a specific resonance frequency. The power supply circuit 16a rectifies and stabilizes this power and supplies it to the CPU 16e to activate the IC chip 16. Memory 16f is ROM (read only memor)
y), RAM (ramdom-access memory) and EEPROM
M (electrically erasable pogramable read only mem
ory), and under the control of the CPU 16e, reads stored data in response to a read command by radio data communication from the writing / reading means 30, which will be described later, and writes data from the writing / reading means 30. Data writing is performed according to the command.

The writing / reading means 30 includes the transmitting / receiving antenna 3
1, a power supply circuit 32 containing a battery, a radio frequency (RF) circuit 33, a modulation circuit 34, and a demodulation circuit 35.
, A CPU 36, and a memory 37, a display 38, and an input device 39 connected thereto. The writing / reading unit 30 activates the IC chip 16 by transmitting a radio wave of a specific frequency to the coil 14 of the optical disc 20 via the transmission / reception antenna 31 and activates the memory 16 of the chip 16.
The information about the optical disc 20 stored in the memory 17f is read out in a non-contact manner by a response signal from the coil 14 which reads and writes data to and receives the data from the coil 14 via the transmitting / receiving antenna 31. Is displayed on the display 38.

In the thus configured optical disk with RFID, information unique to the optical disk 20 such as the title, type, content, storage time, and optical recording start position of the data recorded on the optical disk are stored in the memory 16f of the IC chip 16. And so on. In this case, for a rewritable optical disk, the title of the electronic storage device can be input. The specific input is performed by the input device 3 of the writing / reading unit 30.
9, the input signal of which is transmitted and received by the transmitting and receiving antenna 31.
Is transmitted to the coil 14 of the RFID 13 on a radio wave of a specific frequency. This signal is a binary digital signal. A digital signal emitted from the writing / reading means 30 is emitted from a signal generator (not shown) and is modulated by a modulation circuit 34. The radio frequency (RF) circuit 33 amplifies the modulated signal and transmits it from the transmitting / receiving antenna 31. For example, ASK (amplitude modulation), F
SK (frequency modulation) or PSK (phase modulation).

The transmitted radio wave including the information signal on the optical disk is received by the coil 14 of the RFID 13, and the reception causes the capacitor of the power supply circuit 16a to be charged with the power generated by electromagnetic induction. At this time, the current tends to flow through the reflection film 12 of the optical disk due to the mutual induction of the current flowing through the coil 14, but the notch 1 formed in the reflection film 12
7, the generation of the current is prevented, and a decrease in the Q value is suppressed. In addition, the conductive film 18 formed on the surface of the reflection film 12 has an effect on the resonance circuit including the coil 14 and the capacitor together with the reflection film 12 as a circuit having a small electric resistance. Although a current flows through the conductive film 18 by mutual induction, in the case of a high frequency, the conductive film 18
Even if the resistance is low, the current flowing under the influence of the self-inductance of the conductive film 18 does not increase. Therefore, if the resistance is low, the loss is small and the Q value is high. For this reason, the Q value of the resonance circuit is increased by the conductive film 18, and the power supply circuit 16 a rectifies and stabilizes the power, supplies the power to the CPU 16 e,
Activate the chip 16. Next, the RF of the IC chip 16
The circuit 16b fetches only the signal necessary for demodulation, and the demodulation circuit 16d reproduces the original digital program information signal and stores it in the memory 16f. In this way, information is stored in the memory 16f of the IC chip 16 of each optical disk 10. The optical disk 10 in which information is stored in this manner writes a simple title on a label attached thereto, and is developed in this state. It is stored in the same place with many other optical disks in the room.

In the normal development work, the identification of the optical disk 10 is performed by selecting and extracting a plurality of optical disks 10 on which approximate titles are printed from storage locations. Next, the plurality of optical disks 10 are sequentially opposed to the transmission / reception antenna 31. That is, the writing / reading unit 21 includes the transmitting / receiving antenna 31
A coil which transmits a radio wave of a specific frequency to the coil 14 of the optical disc 20 through the IC to activate the IC chip 16 and reads / writes data to / from the memory 16 f of the chip 16 and receives the data via the transmitting / receiving antenna 31 14
The information about the optical disk 20 stored in the memory 17f is read out in a non-contact manner and displayed on the display 38 according to the response signal from.

More specifically, when the optical disk 10 faces the transmitting / receiving antenna 31, the writing / reading means 30
Transmits the identification code interrogation signal to the coil 14 of the optical disk 10 via the transmission / reception antenna 31 by radio waves of a specific frequency. The interrogation signal in this embodiment is a binarized digital signal. A digital signal emitted from the writing / reading means 30 is emitted from a signal generator (not shown) and is modulated by a modulation circuit 34. The RF circuit 33 amplifies the modulated signal and transmits the amplified signal from the transmitting / receiving antenna 31. The modulation includes, for example, ASK (amplitude modulation), FSK (frequency modulation), or PSK (phase modulation).

The radio wave of the transmitted interrogation signal is
0 is received by the coil 14, and by this reception, the capacitor of the power supply circuit 16a is charged with the power generated by the electromagnetic induction. At this time, the current tends to flow through the reflection film 12 of the optical disk due to the mutual induction of the current flowing through the coil 14, but the notch 17 formed in the reflection film 12 prevents the generation of the current, and the Q value Is suppressed. The conductive film 18 formed on the surface of the protective film 12
Is a capacitor and a coil 1 (not shown) of the power supply circuit 16a.
4 as well as the reflection film 22 as a circuit having a small electric resistance. A current flows through the conductive film 18 due to mutual induction. In the case of a high frequency, the current flowing due to the effect of the self-inductance of the conductive film 18 does not increase even if the resistance of the conductive film 18 is low. The Q value increases. For this reason, the Q value of the resonance circuit is increased by the conductive film 18, and the power supply circuit 16 a rectifies and stabilizes the power, supplies the power to the CPU 16 e,
Activate the chip 16. Next, the RF of the IC chip 16
The circuit 16b fetches only a signal necessary for demodulation, and the demodulation circuit 16d reproduces the original digital signal interrogation signal, and transmits data relating to the optical disk 10 from the memory 16f. The transmission of this data uses the binarized identification code as an IC
The signal is modulated by the modulation circuit 16c of the chip 16, and the RF circuit 16b
This is performed by amplifying the signal and sending it out of the coil 14.

The transmitted data is received by the transmission / reception antenna 31, the RF circuit 33 of the writing / reading means 30 takes in only the signal necessary for demodulation, and the demodulation circuit 35 reproduces the original digital signal to display the data. To be displayed. According to the content displayed on the display 38, the optical disk 1
Since the information content of the optical disk 10 can be known without inserting and reading 0 in the reproducing apparatus, a desired optical disk 10 can be quickly found.
In addition, as a result of specifying the optical disk 10 based on the content displayed on the display 38, the optical disk 10
If nothing is written on the label, it is impossible to identify the optical disk 10 by visual recognition. As described above, in the present invention, various potential applications using the data of the optical disc and the data of the RFID can be developed, such as suppressing theft caused by the identification of the optical disc.

[0021]

Next, examples of the present invention will be described in detail together with comparative examples. <Example 1> An RFID 13 comprising a coil 14 and an IC chip 16 shown in FIG. 1 was formed. That is, 0.5 mm in diameter
Coiled five times on one plane in a spiral
4 was produced. The inner diameter of the coil 14 was 30.5 mm, and the outer diameter was 35.5 mm. An IC chip 16 is connected to both ends of the coil 14 so that the resonance frequency is 13.5M.
Hz was obtained. On the other hand, 76 m made of polycarbonate having a center hole 11a having a diameter of 8 mm
An m × 51 mm disk substrate 11 and a central hole 11 a
A so-called card-type compact disk having a reflective film 12 formed on the surface of a surrounding disk substrate 11 was prepared. A notch 17 having a width of 0.1 mm was formed in the reflective film 12 of the compact disk from the inner edge thereof in a radial direction by 16 mm. The above-mentioned RFID 13 was provided on the reflection film 12 on which the notch 17 was formed in this compact disk. In this case, the distance from the tip of the notch 17 traversing the coil 14 to the outer edge of the coil 14 was 4.25 mm. This optical disk with RFID was used as Example 1.

<Embodiment 2> The outer diameter of the coil 14 is 38 mm.
The same RFID 13 as in Example 1 was obtained except that Then, the RFI is formed on the reflection film 12 of the same optical disk as in the first embodiment in which the notch 17 is formed in the same manner as in the first embodiment.
D13 was provided. In this case, the distance from the tip of the notch 17 traversing the coil 14 to the outer edge of the coil 14 is 3
mm. Further, a conductive film 18 made of aluminum was directly formed between the lead-out portion 12b and a circle 12d concentric with the center hole 11a in contact with the front end of the notch 17 of the reflective film 12. At this time, when the width of the conductive film 18 was 1 cm and the length was 1 cm, the electric resistance value was 0.1Ω. This optical disk with RFID was used as Example 2.

Example 3 A coil 14 was manufactured by spirally winding a coated conductive wire having a diameter of 0.4 mm on a plane 10 times. The inner diameter of the coil 14 is 9 mm, and the outer diameter is 1 mm.
7.5 mm. An IC chip 16 is connected to both ends of the coil 14 so that the resonance frequency becomes 13.5 MHz.
ID13 was obtained. Then, the RFID 13 was provided on the reflective film 12 of the same optical disk as in Example 1 in which the notch 17 was formed in the same manner as in Example 1. In this case, the distance from the tip of the notch 17 traversing the coil 14 to the outer edge of the coil 14 was 13.3 mm. This optical disk with RFID was used as Example 3.

<Embodiment 4> The outer diameter of the coil 14 is 18.5.
RFID 13 which is the same as Example 3 except that
I got Then, this R is formed on the reflection film 12 of the same optical disk as in the first embodiment in which the notch 17 is formed in the same manner as in the first embodiment.
FID 13 was provided. Notch 17 coil 1 in this case
The distance from the tip traversing No. 4 to the outer edge of the coil 14 was 12.6 mm. Further, the notch 1 of the reflection film 12
The same conductive film 18 as in Example 2 was directly formed between the lead-out portion 12b and the circle 12d concentric with the center hole 11a in contact with the tip of No. 7. This optical disk with RFID was used as Example 4.

Comparative Example 1 A simulated optical disk in which the same RFID as in Example 1 was provided on a plate made of polycarbonate was used as Comparative Example 1. Comparative Example 2 The same RFID as in Example 1 except that the RFID was provided on the reflective film without forming a notch.
The optical disk with the disk was Comparative Example 2. Comparative Example 3 A simulated optical disk in which the same RFID as that of Example 3 was provided on a plate made of polycarbonate was used as Comparative Example 3.

<Comparative Example 4> R was formed without forming a notch.
The same optical disc with RFID as in Example 3 except that FID was provided on the reflective film was used as Comparative Example 4. The outer diameters of the coils of Examples 1 to 4 and Comparative Examples 1 to 4, the distance between the outer edge of the coils and the notch tip, the type of the reflective film and the presence or absence of the conductive film, and the thickness of the coil having the conductive film Table 1 shows the relationship between the resistance and the electrical resistance when the width is 1 cm and the length is 1 cm.

<Comparative Test 1 and Evaluation> After measuring the self-inductances L and Q values of the coils in the RFIDs of the optical discs of Examples 1 to 4 and Comparative Examples 1 to 4, the transmission / reception antenna 31 of the writing / reading means 30 was measured. To each R
The operating distance was measured by bringing the optical disk with FID closer. Table 1 shows the results.

[0028]

[Table 1]

From the results of Comparative Example 1 and Comparative Example 3, it can be seen that the RFID used in the examples operates normally. However, it can be seen from the results of Comparative Examples 2 and 4 that even an RFID that operates normally does not operate after being provided directly without forming a notch in the reflective film of the optical disk. This is because the voltage is applied by the mutual induction by the current flowing through the coil 14 of the reflection film 12, the current flows, and energy loss occurs, and the RFID 1
It is considered that this was caused by a decrease in the Q value of 3.

On the other hand, as is evident from the results of the first and third embodiments, the RF that does not operate if it is provided as it is is provided.
It can be seen that even if the ID 13 is used, a normal operation can be achieved by forming the notch 17 in the reflection film 12. This is probably because the notch 17 formed in the reflective film 12 prevented the generation of current in the reflective film 12 that affects the Q value of the coil 14 and suppressed the decrease in the Q value. Furthermore, as is clear from the results of Example 2 and Example 4, it can be seen that the working distance can be extended by forming the conductive film 18 on the reflective film 12. This is conductive film 1
This is considered to be due to the fact that the decrease in the Q value of the coil 14 was further suppressed by the step 8.

[0031]

As described above, according to the present invention, the coil is formed by winding one or more times around the center hole and the IC chips connected to both ends of the coil. Since the RFID is provided on the surface of the reflective film between the hole edge of the center hole and the lead-in portion, the information content on the optical disc can be promptly transmitted in relation to another device that emits information by exchanging information with the RFID. You can know. In this case, since a notch in the radial direction was formed in the reflective film so that the tip crossed the coil from the inner edge of the reflective film and was more than 2.5 mm away from the outer edge of the coil, current was applied to the reflective film by mutual induction by the current flowing through the coil. To prevent it from flowing,
It is possible to suppress a decrease in the Q value of the RFID due to the energy loss.

Further, if a conductive film is formed directly or via a protective film on the reflective film between the circle which is concentric with the center hole and in contact with the tip of the notch and the lead-out portion, the conductive film is formed by mutual induction. Although current flows, at high frequencies, even if the resistance of the conductive film is low, the flowing current does not increase due to the effect of the self-inductance of the conductive film.
The value will be higher. Therefore, by providing the conductive film, the Q value can be further increased, and the information content recorded on the optical disk can be reliably obtained without actually reproducing. Note that when the conductive film has a width of 1 cm and a length of 1 cm and the electric resistance value of the conductive film is 0.25Ω or less, the Q value due to the loss due to the conductive film is effectively increased to increase the RFI.
D can be operated reliably.

[Brief description of the drawings]

FIG. 1B shows an optical disk with RFID according to the present invention;
-B line sectional drawing.

FIG. 2 is a plan view of the optical disc.

FIG. 3 is a conceptual diagram showing a configuration of the RFID and a writing / reading device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Optical disk 11 Disk substrate 11a Center hole 12 Reflective film 12a Lead-in part 12b Lead-out part 12c Pit 12d Circle concentric with the center hole in contact with the notch tip 13 RFID 14 Coil 16 IC chip 17 Notch 18 Conductive film

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Seiro Yawata 1-6-1 Otemachi, Chiyoda-ku, Tokyo F-term (reference) in IP Services Co., Ltd. 5D029 LB03 LC11 MA14 MA18 PA01 VA07

Claims (3)

[Claims] 1. A disk substrate (11) having a central hole (11a).
A reflective film (12) is formed on the surface around the center hole (11a), and information is provided as a pit (12c) between a lead-in part (12a) and a lead-out part (12b) of the reflective film (12). A coil (14) formed by winding one or more times around the center hole (11a) in an optical disc (10) configured to be storable, and IC chips connected to both ends of the coil (14). (16) is provided on the surface of the reflection film (12) between the hole edge of the center hole (11a) and the lead-in portion (12a), and the reflection film ( A notch (17) in the radial direction whose tip is separated from the outer edge of the coil (14) by 2.5 mm or more across the coil (14) from the inner edge of (12) is formed in the reflective film (12). Characteristic optical disk with RFID. 2. A notch (17) concentric with the center hole (11a).
2. The optical disk with RFID according to claim 1, wherein a conductive film is formed directly or via a protective film on the reflective film between the circle (12d) contacting the tip of the lead and the lead-out portion (12b). 3. When the conductive film (18) has a width of 1 cm and a length of 1 cm, the electric resistance of the conductive film (18) is 0.2.
3. The optical disk with RFID according to claim 2, which has a resistance of 5 Ω or less.