JP2008034014A - Optical disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further enhance communication efficiency by a loop antenna in an optical disk having the loop antenna and an IC chip. <P>SOLUTION: The optical disk has the loop antenna 3 and the IC chip 4 performing non-contact communication via the loop antenna 3. The loop antenna 3 is provided so as to enclose the hole 10 of the center of the optical disk. A first conductive layer 5 is provided so as to imperfectly enclose the hole 10 by being partially omitted and rounded on the periphery of the hole 10. One end of the first conductive layer 5 is connected to one end of the loop antenna 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical disc.

  Optical discs have optically readable data recording areas such as read-only optical discs, write once optical discs and rewritable optical discs, and various types of optical discs such as various CDs and various DVDs. is there. In these optical discs, a reflective layer (for example, an aluminum layer) made of a conductive material generally involved in optical data reading is generally formed in the data recording area. This reflective layer is provided so as to completely surround the hole by circling around the central hole of the optical disc without being partially lost.

  Conventionally, such optical discs that include a loop antenna and an IC chip that performs non-contact communication via the loop antenna have been proposed (the following Patent Documents 1, 2, 3, etc.). . The IC chip has a read-only or readable / writable nonvolatile memory.

  An optical disc having such a loop antenna and an IC chip is used together with the following disc device as disclosed in Patent Document 3, for example. That is, in the disk device, in addition to the original function of writing and / or reading information to and from the data recording area of the optical disk, the optical disk rotates for writing and / or reading information to and from the data recording area. A reader and / or writer function is provided for writing and / or reading information to and from the memory of the IC chip of the optical disc. In such a disk device, in order to realize the reader and / or writer function, the stationary part is provided with a loop antenna that performs non-contact communication with the loop antenna of the optical disk by electromagnetic induction. It has been.

  In the optical disc disclosed in Patent Document 1, no special conductive layer or magnetic layer is formed other than the reflective layer. In Patent Document 3, not only the special conductive layer and the magnetic layer but also the reflective layer is not mentioned at all.

On the other hand, in the optical disc disclosed in Patent Document 2, a special magnetic layer is not formed, but a conductive layer is formed so as to cover the reflective layer, and this conductive layer has a hole in the center of the optical disc. It is provided so as to completely surround the hole by orbiting without partially missing around the hole. Patent Document 2 describes that the Q value of a resonant circuit including the loop antenna can be increased by forming the conductive layer. An increase in the Q value means that the loss of the resonance circuit is reduced and the communication efficiency of the loop antenna is increased.
FIG. 1 of JP-A-11-86347 Japanese Patent Laid-Open No. 2001-210057 JP 2005-209323 A

  Needless to say, in the optical disk having the loop antenna and the IC chip as described above, further improvement in communication efficiency by the loop antenna is required.

  An object of the present invention is to provide an optical disc having a loop antenna and an IC chip, which can further improve the communication efficiency of the loop antenna.

  In order to solve the above problems, an optical disc according to a first aspect of the present invention is an optical disc having a loop antenna and an IC chip that performs non-contact communication via the loop antenna, and the loop antenna includes the loop antenna, A first conductive layer provided so as to surround the central hole of the optical disc, and partially surrounding the hole so as to surround the hole incompletely by surrounding the hole; is there.

  According to the experiment of the present inventor, when the first conductor layer is provided so as to surround the hole incompletely by partially wrapping around the central hole as in the first aspect, If the distribution ratio of the eddy current loss due to the recording layer of the optical disk changes and the Q value of the resonant circuit including the loop antenna may be higher than the case where the first conductive layer is not provided. As compared with the case where the first conductive layer is circulated without partially missing around the central hole as in Patent Document 2, the Q value is compared with the case where the hole is completely surrounded. Was confirmed to be high. This is because, in the first mode, the central hole is partially omitted and circulated, so that an eddy current component that circulates around the central hole flows in the first conductive layer. It is considered that the eddy current loss is reduced due to the disappearance, and thereby the Q value is increased. Therefore, according to the first aspect, it is possible to design the communication efficiency to be higher than that of the conventional technique described above.

  By the way, when an optical disk is mounted on a disk device as described above, for example, the metal that constitutes the disk device is positioned in the vicinity of the optical disk, and stray capacitance (unstable capacity) between the metal and the optical disk. ) Form a part of a resonance circuit including the loop antenna. Accordingly, if the contribution ratio of the stray capacitance is high, the resonance frequency of the resonance circuit may be unstable and relatively large and communication by the loop antenna may become unstable. On the other hand, in the first aspect, a predetermined stable capacitance is additionally loaded in the resonance circuit including the loop antenna by the first conductive layer. Therefore, according to the first aspect, since the contribution ratio of the stray capacitance is reduced, a configuration for performing stable communication is possible. In order to perform stable communication by reducing the contribution ratio of the stray capacitance, it is conceivable to mount a chip capacitor. However, in this case, the thickness of the optical disk is considerably increased by the chip type capacitor, and the rotational balance of the optical disk may be lost due to the eccentric load by the chip type capacitor. On the other hand, in the first aspect, since the electrostatic capacity is loaded by the first conductive layer, the optical disk is hardly increased in thickness and can be arranged so as to reduce the eccentric load.

  An optical disk according to a second aspect of the present invention is the optical disk according to the first aspect, wherein the first conductive layer is partially electrically connected to the loop antenna.

  Even if the shape, arrangement, etc. of the first conductive layer are the same, if the first conductive layer is partially connected to the loop antenna as in the second mode, the first conductive layer is looped. The capacitance loaded by the first conductive layer can be increased compared to the case where the antenna is not connected. Therefore, according to the second aspect, the contribution rate of the stray capacitance can be further reduced, and communication can be performed more stably.

  The optical disc according to a third aspect of the present invention is the optical disc according to the second aspect, wherein at least a portion overlaps at least a portion of the first conductive layer via an insulating material and does not completely surround the hole. A second conductive layer provided, wherein the second conductive layer is electrically connected to a portion of the loop antenna that is different from the portion to which the first conductive layer is connected. .

  According to the third aspect, a stable capacitance between the first and second conductive layers is additionally loaded in the resonance circuit including the loop antenna. Therefore, according to the third aspect, it is possible to further reduce the contribution ratio of the stray capacitance, and to perform communication more stably.

  In the third aspect, it is preferable that the first conductive layer is electrically connected to one end of the loop antenna, and the second conductive layer is electrically connected to the other end of the loop antenna. However, it is not necessarily limited to this.

  An optical disk according to a fourth aspect of the present invention is the optical disk according to any one of the first to third aspects, wherein the first conductive layer and the loop antenna are arranged on the same plane.

  There are not only so-called single-sided optical disks but also so-called double-sided optical disks. A double-sided type optical disc can write and / or read information from / to the data recording area on either side of the front and back. The direction of the surface of the optical disc is changed. According to the third aspect, since the first conductive layer and the loop antenna are arranged on the same plane, the orientation of the surface of the optical disc mounted on the disc device can be any orientation. The relative positions of the loop antenna of the optical disc and the first conductive layer with respect to the loop antenna on the optical disc apparatus side do not change much. Therefore, according to the third aspect, when the optical disc is a double-sided type, the communication sensitivity of the loop antenna is made substantially the same regardless of the orientation of the optical disc mounting surface with respect to the optical disc apparatus. be able to.

  An optical disk according to a fifth aspect of the present invention is the optical disk according to any one of the first to third aspects, wherein at least a part of the first conductive layer overlaps with the loop antenna. In this case, it is preferable that at least a part of the first conductive layer overlaps with substantially the entire loop antenna.

  According to the fifth aspect, since at least a part of the first conductive layer overlaps the loop antenna, the first conductive layer does not overlap the loop antenna at all (for example, the first conductive layer 4), the capacitance loaded by the first conductive layer is increased. Therefore, according to the fifth aspect, it is possible to further reduce the contribution ratio of the stray capacitance, and to perform communication more stably.

  An optical disc according to a sixth aspect of the present invention is the optical disc according to any one of the first to fifth aspects, wherein the data recording area includes a reflective layer made of a conductive material involved in optical data reading, The conductive layer is electrically insulated from the reflective layer.

  In the sixth aspect, an example of an optical disk provided with a reflective layer made of a conductive material in a data recording area is given. However, the first to fifth aspects are not necessarily limited to this. Absent.

  An optical disk according to a seventh aspect of the present invention is the optical disk according to the sixth aspect, wherein all or part of the first conductive layer overlaps the reflective layer.

  In the seventh aspect, an example of the relationship between the first conductive layer and the reflective layer is given. In the sixth aspect, the first conductive layer does not overlap the reflective layer at all. May be.

  An optical disc according to an eighth aspect of the present invention is the optical disc according to any one of the first to seventh aspects, wherein the IC chip is missing the conductive layer when the conductive layer imperfectly surrounds the hole. It is arranged near the place.

  According to the eighth aspect, since the IC chip is arranged near the missing portion, the area efficiency of the arrangement is improved.

  An optical disk according to a ninth aspect of the present invention is the optical disk according to any one of the first to eighth aspects, wherein the first conductive layer is made of a magnetic material having conductivity. It is preferable to use a high permeability magnetic material as the magnetic material. Examples of the high magnetic permeability magnetic material having conductivity include permalloy and silicon steel. In the first to eighth aspects, the first conductive layer may be made of a nonmagnetic material such as copper, silver, or aluminum.

  According to the ninth aspect, since the first conductive layer is made of a magnetic material, the magnetic flux generated with communication by the loop antenna can be guided or shielded by the conductive layer. Therefore, according to the ninth aspect, for example, it is possible to reduce eddy current loss by reducing magnetic flux entering the reflection layer and the like, thereby further improving communication efficiency.

  An optical disk according to a tenth aspect of the present invention includes the substrate provided with the loop antenna, the IC chip, and the first conductive layer in any one of the first to ninth aspects, the loop antenna, The substrate on which the IC chip and the first conductive layer are provided is affixed on the disk main body or embedded in the disk main body.

  According to the tenth aspect, a substrate on which the loop antenna, the IC chip, and the first conductive layer are provided is prepared separately from the other elements, and the substrate is attached to the separately prepared disc body. Alternatively, the optical disk can be manufactured by embedding the substrate when manufacturing the disk main body. Therefore, according to the tenth aspect, the optical disk can be easily manufactured as compared with the optical disk having the structure not using the substrate.

  An optical disk according to an eleventh aspect of the present invention is the optical disk according to the tenth aspect, wherein the substrate is made of a magnetic material. The magnetic material is preferably a material having good high frequency characteristics.

  According to the eleventh aspect, since the substrate is made of a magnetic material, it is possible to guide or shield the magnetic flux generated with communication by the loop antenna by the substrate. Therefore, according to the eleventh aspect, for example, the magnetic flux entering the reflective layer or the like is reduced to reduce eddy current loss, thereby further improving communication efficiency.

  According to the present invention, in any one of the first to ninth aspects, the substrate includes a substrate on which the loop antenna and the IC chip are provided, the substrate is made of a conductive material, and the first conductive layer is formed. The substrate on which the loop antenna and the IC chip are provided may be attached on the disk main body or embedded in the disk main body.

  According to the present invention, in the tenth or eleventh aspect, the first conductive layer has a shape in which an inner periphery and an outer periphery are partially omitted from a circular ring concentric with a central hole. In addition, the shape of the conductive layer is changed so that the rotational balance of the optical disc is increased as compared with the case where the first substrate forms a ring whose inner periphery and outer periphery are concentric circles concentric with the central hole. The substrate may be distorted, deformed, or shifted, the shape of the substrate may be distorted, deformed, or shifted from the ring, or both.

  According to the present invention, in an optical disc having a loop antenna and an IC chip, the communication efficiency of the loop antenna can be further improved.

  Hereinafter, an optical disk according to the present invention will be described with reference to the drawings.

  [First Embodiment]

  FIG. 1 is a schematic plan view showing an optical disc according to the first embodiment of the present invention. 2A is a schematic cross-sectional view taken along line A-A ′ in FIG. 1, and FIG. 2B is a schematic cross-sectional view taken along line B-B ′ in FIG. 1.

  The optical disc according to the present embodiment includes a disc main body 1, a substrate 2, a loop antenna 3, an IC chip 4, and a first conductive layer 5.

The disc body 1 is configured in the same manner as, for example, a reproduction-only CD or DVD, CD-R, CD-RW, DVD-R, DVD-RW, or DVD-RAM. In FIG. 2, the structure of the disk main body 1 is shown in a greatly simplified manner. The disk main body 1 is composed of an insulating disk substrate 11 made of polycarbonate or the like constituting the disk main body 1, and aluminum or the like on the disk substrate 11. An example is shown having a reflective layer 12 formed of a conductive material in a data recording area and involved in optical data reading, and a protective layer 13 formed of an insulating material such as a synthetic resin thereon.
A hole constituting the central hole 10 of the optical disc is formed at the center of the disc main body 1.

  In the present embodiment, the substrate 2 is made of an insulating material such as polyimide. The substrate 2 is preferably a flexible substrate, but may be a rigid substrate. In the present embodiment, the substrate 2 has an annular shape having a diameter smaller than the outer diameter of the disc main body 1 and is adhered to the protective layer 13 of the disc main body 1 with an adhesive (not shown). . The substrate 2 is disposed concentrically with the disc main body 1, and a hole constituting the central hole 10 is formed at the center of the substrate 2.

  The loop antenna 3 is provided so as to surround the hole 10. In the present embodiment, the loop antenna 3 is spirally wound a plurality of times, but is not limited to this, and may be wound only once, for example. In the present embodiment, the loop antenna 3 is formed in a central region where the reflective layer 12 is not formed, and does not overlap the reflective layer 12. One end of the loop antenna 3 is connected to one terminal of the IC chip 4 via a connection pad 6a. The other end of the loop antenna 3 is connected to the other terminal of the IC chip 4 via a jumper wire 7 and a connection pad 6b.

  The IC chip 4 performs non-contact communication via the loop antenna 3 and is not shown in the drawing, but includes an RF (wireless high frequency) circuit, a modulation circuit, a demodulation circuit, a CPU, a memory, a power supply circuit, and the like. And is operated by electric power supplied via the loop antenna 3, and data can be written to and / or read from the memory by communication via the loop antenna 3. As the IC chip 4, for example, a commercially available IC tag or RFID can be used.

  The first conductive layer 5 is provided so as to partially surround the hole 10 by partially missing around the hole 10 and circulating around. In the present embodiment, the first conductive layer 5 is disposed along the outer periphery of the loop antenna 3 on the outer periphery side of the loop antenna 3, and a part of the circular ring concentric with the hole 10 is omitted. It has a shape. The IC chip 4 and the connection pads 6 a and 6 b are arranged at the missing portions of the first conductive layer 5. Therefore, when the loop antenna 3, the IC chip 4, and the first conductive layer 5 are arranged on the same surface of the substrate 2, the area efficiency of the arrangement is improved. One end of the first conductive layer 5 is connected to the connection pad 6a, and is connected to one end of the loop antenna 3 through the connection pad 6a. The partial connection between the first conductive layer 5 and the loop antenna 3 is not necessarily limited to the connection between one end of the first conductive layer 5 and one end of the loop antenna 3. 5 may be connected between one end of the loop antenna 3 and one end of the loop antenna 3, or may be connected between one end of the first conductive layer 5 and a midpoint of the loop antenna 3. Good. Note that the first conductive layer 5 is electrically insulated from the reflective layer 12.

  In the present embodiment, the loop antenna 3, the connection pads 6a and 6b, and the first conductive layer 5 are formed on the upper surface of the substrate 2 as a pattern of a conductive material such as copper, silver, or aluminum. The IC chip 4 is provided on the upper surface of the substrate 2.

  Although not shown in the drawings, the loop antenna 3, the connection pads 6a and 6b, the first conductive layer 5 and the like on the upper surface of the substrate 2 are covered with a protective layer such as an insulating resin as necessary. Also good.

  Here, an example of the manufacturing method of the optical disk according to the present embodiment will be described. First, an ordinary optical disk such as a CD or a DVD that does not have the loop antenna 3 and the IC chip 4 is prepared as the disk body 1. On the other hand, the substrate 2 provided with the loop antenna 3, the IC chip 4, the first conductive layer 5, the connection pads 6 a and 6 b, and the jumper wires 7 is prepared using a normal circuit board technology. And this board | substrate 2 is affixed on the disk main body 1 with an adhesive agent. Thereby, the optical disc according to the present embodiment is completed. In this embodiment, the IC chip 4, the loop antenna 3, the first conductive layer 5, etc. are not provided directly on the protective layer 13 constituting the disk body 1, but the substrate 2 is used. Apart from 1, the substrate 2 side can be manufactured. Therefore, the optical disk according to the present embodiment can be manufactured more easily than an optical disk having a structure that does not use the substrate 2. However, the optical disk according to the present invention does not necessarily need to use such a substrate 2.

  In order to confirm the effect of the first conductive layer 5 in the optical disk according to the present embodiment, the inventor conducted a simulation experiment as described below. That is, a substrate on which a loop antenna and an IC chip corresponding to the loop antenna 3 and the IC chip 4 in FIGS. 1 and 2 are mounted on a commercially available DVD (the first conductive layer 5 is not formed on this substrate). .) Was pasted. Then, the Q value of the resonance circuit including the loop antenna was measured in the optical disk in this state (referred to as “conductive layer non-attached state”).

  Further, a C-shaped copper foil was affixed to the periphery of the loop antenna 3 with respect to the optical disk without the conductive layer attached, by partially removing the annular copper foil. At this time, the C-shaped copper foil is insulated from the loop antenna 3 (referred to as a “C-shaped conductive layer mounting insulation state”), and a part of the C-shaped copper foil is attached to one end of the loop antenna 3. It was in an electrically connected state (referred to as “C-shaped conductive layer attached connection state”). Then, the Q value of the resonance circuit including the loop antenna was measured in the C-shaped conductive layer-mounted insulating optical disk. In addition, the Q value of the resonance circuit including the loop antenna was measured on the optical disk with the C-shaped conductive layer mounted and connected.

  As a result, it is experimentally possible that the Q value in the C-shaped conductive layer mounting insulation state and the Q value in the C-shaped conductive layer mounting connection state can be higher than the Q value in the conductive layer non-mounting state. I understood. This is because, in the C-shaped conductive layer insulation connection state and the C-shaped conductive layer mounting connection state, the C-shaped copper foil (C-shaped conductive layer) circulates partially missing the central hole. In the C-shaped copper foil layer, the eddy current that circulates around the central hole stops flowing, and the distribution ratio with the eddy current loss of the optical recording layer is changed, so the eddy current loss is reduced. Thus, it is considered that the Q value becomes high. Therefore, according to the present embodiment, it has been experimentally found that a configuration in which communication efficiency is further improved is possible.

  The optical disk according to the present embodiment is used together with a disk device as disclosed in Patent Document 3, for example. That is, in this disk device, in addition to the original function of writing and / or reading information to and from the data recording area of the optical disk by an optical pickup or the like, the above-mentioned information writing and / or reading for the data recording area is performed. A reader and / or writer function is provided for writing and / or reading information to and from the memory of the IC chip of the optical disk when the optical disk is rotating. In such a disk device, in order to realize the reader and / or writer function, the stationary part is provided with a loop antenna that performs non-contact communication with the loop antenna of the optical disk by electromagnetic induction. It has been.

  Although not shown in the drawings, the optical disk according to the present embodiment is mounted so that the loop antenna of the optical disk apparatus faces the loop antenna 3 on the upper side in FIG. 2 when mounted on such an optical disk apparatus. Is done. Optical reading and / or writing is performed from the lower side in FIG.

  When the optical disk according to the present embodiment is mounted on such a disk device, for example, the metal constituting the disk device is positioned in the vicinity of the optical disk, and stray capacitance (unstable capacity) between the metal and the metal is located. ) Form a part of a resonance circuit including the loop antenna 3. Therefore, if the contribution ratio of the stray capacitance is high, the resonance frequency of the resonance circuit is unstable and relatively large and communication by the loop antenna 3 becomes unstable. On the other hand, in the present embodiment, a predetermined stable capacitance is additionally loaded by the first conductive layer 5 in the resonance circuit including the loop antenna 3. Therefore, according to the first aspect, since the contribution ratio of the stray capacitance is reduced, stable communication can be performed. In order to perform stable communication by reducing the contribution ratio of the stray capacitance, it is conceivable to mount a chip capacitor. However, in this case, the thickness of the optical disk may be considerably increased due to the chip type capacitor, or the rotational balance of the optical disk may be lost due to the eccentric load due to the chip type capacitor. On the other hand, in the present embodiment, since the electrostatic capacity is loaded by the first conductive layer 5, the thickness of the optical disk is hardly increased and the arrangement for reducing the eccentric load is easy.

  Even if the shape, arrangement, etc. of the first conductive layer 5 are the same, if the first conductive layer 5 is partially connected to the loop antenna 3 as in the present embodiment, the first conductive layer 5 is looped. Compared with the case where the antenna 3 is not connected, the capacitance loaded by the first conductive layer 5 can be increased. Therefore, according to the present embodiment, the contribution rate of the stray capacitance can be further reduced, and communication can be performed more stably. However, in the present invention, the first conductive layer 5 and the loop antenna 3 are not necessarily electrically connected.

  In the present embodiment, the first conductive layer 5 has a shape in which the inner periphery and the outer periphery are part of a circular ring that is concentric with the central hole 10 and the substrate 2 has an inner periphery. In addition, the outer periphery forms a ring that is a perfect circle concentric with the central hole. However, although not shown in the drawings, the shape of the first conductive layer 5 is distorted or deformed from the above shape or shifted so that the rotational balance of the optical disk is further increased, or the shape of the substrate 2 is changed from the annular shape. It may be distorted, deformed, displaced, or both.

  In the present embodiment, as described above, the first conductive layer 5 is made of a nonmagnetic material such as copper, silver, or aluminum, and the substrate 2 is made of a nonmagnetic material such as polyimide. In the present invention, instead, one or both of the first conductive layer 5 and the substrate 2 may be made of a magnetic material (preferably a high magnetic permeability magnetic material). As an example of the conductive magnetic material (particularly, the high magnetic permeability magnetic material) constituting the first conductive layer 5, permalloy or the like can be given.

  When the substrate 2 is made of a magnetic material, the magnetic flux from the loop antenna (the loop antenna facing the loop antenna 3 on the upper side) of the optical disk device described above is guided or shielded by the substrate 2, and the magnetic flux entering the reflective layer 12 and the like is reduced. Is done. As a result, the eddy current layer of the reflective layer 12 generated by the magnetic flux entering the reflective layer 12 is reduced, thereby further improving the communication efficiency.

  By the way, the optical disc according to the present embodiment may be configured as a so-called single-sided type or a so-called double-sided type. When configured as a double-sided type, the upper and lower surfaces of the optical disc are reversed when the optical disc is loaded into the disc device, depending on which side the information is written to and / or read from the optical disc device. In the present embodiment, since the first conductive layer 5 and the loop antenna 3 are arranged on the same plane, the optical disk device side is free from any orientation of the optical disk mounting surface with respect to the disk device. The relative positions of the loop antenna 3 and the first conductive layer 5 of the optical disc with respect to the loop antenna of FIG. Therefore, if the loop antenna 3 and the first conductive layer 5 are arranged on the same plane as in the present embodiment, when the optical disc is a double-sided type, the orientation of the optical disc mounting surface with respect to the optical disc device will be Even in the direction of, the communication sensitivity by the loop antenna 3 can be made substantially the same.

  [Second Embodiment]

  FIG. 3 is a cross-sectional view showing an optical disc according to the second embodiment of the present invention. FIG. 3 (a) corresponds to FIG. 2 (a), and FIG. 3 (b) corresponds to FIG. ing. 3, elements that are the same as or correspond to those in FIGS. 1 and 2 are given the same reference numerals, and redundant descriptions thereof are omitted.

  The present embodiment is basically different from the first embodiment in that the loop antenna 3, the IC chip 4, the first conductive layer 5, the connection pads 6a and 6b, and the first embodiment are different from the first embodiment. The substrate 2 provided with the jumper wire 7 is attached to the disk body 1 with an adhesive, whereas the loop antenna 3, the IC chip 4, the first conductive layer 5, the connection pads 6a and 6b, and the jumper The only difference is that the substrate 2 provided with the line 7 is embedded in the disc body 1.

  An example of an optical disk and a manufacturing method according to the present embodiment will be described. First, the disk main body 1 in a state immediately before forming the protective layer 13 is prepared. On the other hand, the substrate 2 provided with the loop antenna 3, the IC chip 4, the first conductive layer 5, the connection pads 6 a and 6 b, and the jumper wires 7 is prepared using a normal circuit board technology. Next, the disc body 1 immediately before the formation of the protective layer 13 is placed in a mold for forming the protective layer 13 by resin molding, and the loop antenna 3, the IC chip 4, the first conductive layer 5, and the connection pad 6a. , 6b and the jumper wire 7 are set on the disk main body 1 immediately before the protective layer 13 is formed. Thereafter, the protective layer 13 is formed by resin molding. Thereby, the optical disk according to the present embodiment can be manufactured.

  Also in this embodiment, the same advantages as those in the first embodiment can be obtained.

  [Third Embodiment]

  FIG. 4 is a schematic plan view showing an optical disc according to the third embodiment of the present invention. FIG. 5 is a schematic plan view of the substrate 2 as viewed from the lower surface side. 6A is a schematic cross-sectional view taken along line C-C ′ in FIG. 4, and FIG. 6B is a schematic cross-sectional view taken along line D-D ′ in FIG. 4. 4 to 6, the same or corresponding elements as those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description thereof is omitted.

  This embodiment is basically different from the first embodiment in that the first conductive layer 5 is formed on the upper surface of the substrate 2 in the first embodiment, whereas the first embodiment is different from the first embodiment. In the embodiment, the loop antenna 3 is disposed at a position overlapping the reflective layer 12, the first conductive layer 5 is formed on almost the entire lower surface of the substrate 2, and the first conductive layer 5 is the most part of the loop antenna 3. It is only the point which overlaps. The connection pad 6a and the vicinity of one end in the circumferential direction of the first conductive layer 5 are electrically connected by a through hole (not shown). However, in the present invention, it is not always necessary to electrically connect both. Note that a slit-shaped region 2 a in FIG. 5 indicates a region where the first conductive layer 5 is not formed on the lower surface of the substrate 2.

  According to the present embodiment, the same advantages as those of the first embodiment can be obtained.

  Further, according to the present embodiment, since the first conductive layer 5 overlaps with the loop antenna 3, the first conductive layer 5 does not overlap with the loop antenna 3 at all compared to the first embodiment. Thus, the electrostatic capacity loaded by the first conductive layer 5 is increased. Therefore, according to the present embodiment, the contribution rate of the stray capacitance can be further reduced, and communication can be performed more stably.

  Also in this embodiment, as in the first embodiment, the first conductive layer 5 is made of a nonmagnetic material such as copper, silver or aluminum, and the substrate 2 is made of a nonmagnetic material such as polyimide. ing. In the present invention, instead, one or both of the first conductive layer 5 and the substrate 2 may be made of a magnetic material (preferably a high magnetic permeability magnetic material). Examples of magnetic materials (particularly, high magnetic permeability magnetic materials) include ferrite.

  [Fourth Embodiment]

  FIG. 7 is a schematic plan view showing an optical disc according to the fourth embodiment of the present invention. FIG. 8 is a schematic plan view of the optical disc shown in FIG. 7 viewed from the lower surface side. FIG. 9A is a schematic cross-sectional view taken along line E-E ′ in FIG. 4, and FIG. 9B is a schematic cross-sectional view taken along line F-F ′ in FIG. 4. 7 to 9, the same or corresponding elements as those in FIGS. 1 to 3 are denoted by the same reference numerals, and redundant description thereof is omitted.

  This embodiment is fundamentally different from the second embodiment in that the substrate 2 is configured to have a relatively small diameter and that the first conductive layer 5 is disposed inside the loop antenna 3. And the second conductive layer 25 is provided on the lower surface of the substrate 2 so as to overlap the entire first conductive layer 5. In the present embodiment, the substrate 2 is made of an insulating material. When the substrate 2 is made of a conductive material, an insulating layer is formed on the upper surface of the substrate 2, and the loop antenna 3 and the first conductive layer 5 are formed thereon, and an insulating layer is formed on the lower surface of the substrate 2, A second conductive layer 25 may be formed thereunder.

  In the present embodiment, a connection pad 26b is formed on the lower surface of the substrate 2, and the connection pad 26b and the connection pad 6b on the upper surface of the substrate 2 are electrically connected by a through hole (not shown). Thus, the second conductive layer 25 is electrically connected to the other end of the loop antenna 3. Also in the present embodiment, the first conductive layer 5 is electrically connected to one end of the loop antenna 3.

  In the present embodiment, the entire second conductive layer 25 just overlaps the entire first conductive layer 5, but when the second conductive layer 25 is provided, at least the second conductive layer 25 is provided. It suffices that part of the first conductive layer 5 overlaps at least part of it.

  According to this embodiment, the same advantages as those of the first and second embodiments can be obtained.

  Further, according to the present embodiment, in the resonance circuit including the loop antenna 3, the capacitance between the first and second conductive layers 5 and 25 (that is, stable capacitance) is further increased. It will be loaded additionally. Therefore, according to the present embodiment, the contribution rate of the stray capacitance can be further reduced, and communication can be performed more stably.

  As mentioned above, although each embodiment of this invention and its modification were demonstrated, this invention is not limited to these.

1 is a schematic plan view showing an optical disc according to a first embodiment of the present invention. 1 is a schematic cross-sectional view showing an optical disc according to a first embodiment of the present invention. It is a schematic sectional drawing which shows the optical disk by the 2nd Embodiment of this invention. It is a schematic plan view which shows the optical disk by the 3rd Embodiment of this invention. It is the schematic plan view which looked at the board | substrate in FIG. 4 from the lower side. It is a schematic sectional drawing which shows the optical disk by the 3rd Embodiment of invention. It is a schematic plan view which shows the optical disk by the 4th Embodiment of this invention. It is the schematic plan view which looked at the optical disk by the 4th Embodiment of this invention from the lower side. It is a schematic sectional drawing which shows the optical disk by the 4th Embodiment of invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Disc main body 2 Board | substrate 3 Loop antenna 4 IC chip 5 1st conductive layer 10 Center hole 12 Reflective layer 25 2nd conductive layer

Claims (11)

An optical disc having a loop antenna and an IC chip that performs non-contact communication via the loop antenna,
The loop antenna is provided so as to surround a central hole of the optical disc,
An optical disc comprising: a first conductive layer provided so as to partially surround the hole so as to partially surround the hole so as to surround the hole incompletely.   The optical disk according to claim 1, wherein the first conductive layer is partially electrically connected to the loop antenna. A second conductive layer provided so that at least a portion thereof overlaps at least a portion of the first conductive layer via an insulating material and does not completely surround the hole;
3. The optical disk according to claim 2, wherein the second conductive layer is electrically connected to a portion of the loop antenna that is different from a portion to which the first conductive layer is connected.   4. The optical disc according to claim 1, wherein the first conductive layer and the loop antenna are arranged on the same plane.   4. The optical disc according to claim 1, wherein at least a part of the first conductive layer overlaps with the loop antenna.   6. The reflective layer made of a conductive material involved in optical data reading is provided in a data recording area, and the first conductive layer is electrically insulated from the reflective layer. An optical disc according to any one of the above.   The optical disk according to claim 6, wherein all or part of the first conductive layer overlaps with the reflective layer.   8. The IC chip according to claim 1, wherein the IC chip is disposed near a portion where the first conductive layer is missing when the first conductive layer completely surrounds the hole. An optical disk according to the above.   9. The optical disc according to claim 1, wherein the first conductive layer is made of a magnetic material having conductivity. A substrate provided with the loop antenna, the IC chip and the first conductive layer;
10. The substrate according to claim 1, wherein the substrate on which the loop antenna, the IC chip, and the first conductive layer are provided is affixed on the disk body or embedded in the disk body. An optical disk according to the above.   The optical disk according to claim 10, wherein the substrate is made of a magnetic material.

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