WO1999046770A1 - Disque optique - Google Patents

Disque optique Download PDF

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Publication number
WO1999046770A1
WO1999046770A1 PCT/JP1999/000882 JP9900882W WO9946770A1 WO 1999046770 A1 WO1999046770 A1 WO 1999046770A1 JP 9900882 W JP9900882 W JP 9900882W WO 9946770 A1 WO9946770 A1 WO 9946770A1
Authority
WO
WIPO (PCT)
Prior art keywords
disk
lower surfaces
optical disc
optical
reflected light
Prior art date
Application number
PCT/JP1999/000882
Other languages
English (en)
Japanese (ja)
Inventor
Hideki Izumi
Original Assignee
Hideki Izumi
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hideki Izumi filed Critical Hideki Izumi
Publication of WO1999046770A1 publication Critical patent/WO1999046770A1/fr

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material

Definitions

  • the present invention relates to an optical disc, and more particularly, to an optical disc on which information signals are recorded or reproduced by irradiating one laser beam.
  • optical disks As an optical disk on which information signals are recorded or reproduced by irradiating a single laser beam, various types of recording such as magneto-optical disks, write-once optical disks, digital audio disks (so-called compact disks (CD)), optical video disks, etc.
  • the medium has been put to practical use.
  • Each of these optical discs includes a transparent substrate formed of a resin such as acrylic or polycarbonate or glass, and a reflective film formed on a main surface of the substrate.
  • an array of concave pits is formed on a substrate to serve as an information recording unit.
  • the depth of the pit is about one to four wavelengths of one laser beam to be irradiated.
  • a reflective film is formed on the information recording section.
  • laser light is applied to a reflective film covering the pit in accordance with an information signal, and reproduction is performed by detecting a change in reflectance caused by interference of light caused by the laser light.
  • Audio CDs have excellent physical properties, and the operation of the CD player is simple, so the current LP record player has almost disappeared.
  • CD players are superior in terms of frequency characteristics, distortion characteristics, SZN ratio, dynamic range, wow and flash, and so on.
  • digital noise commonly called digital noise, which is not included in LP record players, is present in the sound played by CD players. This digital noise affects the harmony and tone that are considered most important in music. Musicians who are sensitive to sound quality have always felt the difference.
  • CD player manufacturers have also been working to solve the above problems. In other words, various R & D activities are being conducted to minimize digital noise generated in electronic circuits.
  • one laser beam is irradiated perpendicular to the disk surface. Then, the intensity of the reflected light, which is reflected by the surface on which the pits (elongated holes) are formed and returns, is detected by an optical pickup. The signal detected by the optical pickup is converted into a digital electric signal to reproduce music information.
  • the pit when the pit is irradiated with the laser beam, a part of the pit is scattered at the edge of the pit.
  • the scattered laser light travels toward the inner edge and the outer edge of the disk while being repeatedly reflected on the upper and lower surfaces of the disk.
  • the scattered laser light reaching the inner or outer edge of the disk will be reflected back there.
  • the scattered laser light generated for each pit is repeatedly reflected in the disk and accumulated, so that it is amplified to an intensity that cannot be ignored. It returns to the direction of the optical pickup and corresponds to the presence or absence of a pit. It overlaps with the reflected light and enters the optical pickup. As a result, the signal detected by the optical pickup does not accurately correspond to the arrangement of the pits.
  • Japanese Utility Model Application Laid-Open No. 5-54883 discloses that the outer or inner edge of an optical disc is coated with a green color that absorbs the hue of a laser beam and absorbs diffusely reflected light. ing. Further, Japanese Patent Application Laid-Open No. 7-933823 discloses a method of making an outer edge, an inner edge, a clamping area, or a corrugation portion of a disk opaque to further diffuse and weaken diffusely reflected light. ing. Further, Japanese Patent Application Laid-Open No. 9-11288813 proposes that a V-shaped groove is provided concentrically in a clamping area, and diffusely reflected light is collected and attenuated in this portion.
  • a CD player rotating an optical disc with stable rotation for playback leads to an improvement in playback sound quality or playback image quality.
  • the sound to be recorded is sampled at 44.1 kHz, and the dynamics are expressed in 256 levels.
  • Music information is recorded in a recording area on the disc surface as a pit array formed with a width of 1 m or less and a track pitch of about 2 m.
  • a laser beam narrowed down to about 1 to 2 m in diameter by an optical pickup is used for reproducing music information.
  • Japanese Patent Application Laid-Open No. 9-2596496 discloses a configuration in which an optical disc is sandwiched between a clamp table and a turntable which are the same as or larger than an optical disc and are rotated. ing. Further, Japanese Patent Application Laid-Open No. 9-63167 discloses a CD player provided with means for adsorbing an optical disk to an evening table. As described above, several methods have been proposed for reducing digital noise other than noise generated in the electronic circuit of a CD player. However, for the irregular reflection of light rays inside the optical disk, a laser light absorber has been developed and marketed, but the effect of expecting more reflection than absorption has not been obtained.
  • a general object of the present invention is to provide an improved useful optical disk which solves the above-mentioned problems.
  • a more specific object of the present invention is to provide an optical disc capable of efficiently emitting reflected light generated by irregular reflection of light rays inside an optical disc to the outside, thereby reducing digital noise caused by the optical disc itself. It is to provide.
  • an optical disc from which recorded information is read by reflected light of an irradiated light beam, wherein the optical disc is inclined with respect to the upper and lower surfaces of the disk and the upper and lower surfaces.
  • An optical disk having an outer edge is provided.
  • the reflected light generated by the irregular reflection inside the disk is emitted from the outer edge end surface to the outside of the disk without being totally reflected by the inclined outer edge surface. Therefore, the internally reflected light is prevented from returning to the optical pickup, and the generation of digital noise can be suppressed.
  • the angle formed by the outer edge and one of the upper and lower surfaces is preferably in the range of 40 to 89 degrees.
  • the outer edge may be flat or curved It may be a plane. Further, the outer edge face may be a face configured by a plurality of faces.
  • an optical disk from which recording information is read by reflected light of an irradiated light beam, wherein the optical disk is provided on the upper and lower surfaces of the disk and the upper and lower surfaces provided inside the substrate at the outer peripheral portion of the disk.
  • An optical disk is provided which has a tilted boundary surface.
  • the reflected light generated by the irregular reflection inside the disk is refracted or reflected at the boundary surface, so that it is diffused or emitted outside the disk.
  • the boundary surface may be a curved surface or an uneven surface.
  • the boundary surface may be defined by a ring-shaped member formed integrally with the disk substrate.
  • the outer peripheral portion of the optical disc may be made of a different material made of a material different from that of the substrate, and the boundary surface may be defined between the different material and the substrate.
  • an optical disk from which recorded information is read by reflected light of an irradiated light beam, wherein the optical disk is provided on the upper and lower surfaces of the disk and at least one of the upper and lower surfaces and extends in a circumferential direction of the disk.
  • An optical disk is provided which has an annular groove extending and having a surface inclined with respect to upper and lower surfaces.
  • the reflected light generated by the irregular reflection inside the disk is refracted or reflected on the inner surface of the annular groove, so that it is diffused or emitted outside the disk.
  • the annular groove is preferably provided on both the upper and lower surfaces. In this case, it is preferable to make the diameter of the annular groove provided on the upper surface different from the diameter of the annular groove provided on the lower surface so as to suppress a decrease in disk strength at this portion.
  • an optical disk from which recorded information is read by reflected light of an irradiated light beam, wherein the information is read between the upper and lower surfaces of the disk and the upper and lower surfaces provided at the outer edge of the disk.
  • An optical disk comprising a plurality of small holes extending in a direction is provided.
  • the reflection caused by the irregular reflection inside the disk The light is refracted or reflected at the small holes, so that it is diffused or emitted outside the disk.
  • the small holes may have any cross-sectional shape as long as they penetrate the upper and lower surfaces of the disk. Further, the extending direction of the small hole may be perpendicular to the upper and lower surfaces, or may be inclined at a certain angle.
  • the small holes are provided in a plurality of rows in the circumferential direction of the disk, and the small holes in each row are arranged alternately. Further, the above-mentioned small hole may be provided near the inner edge of the disk.
  • FIG. 1A is a partially enlarged cross-sectional view of a CD according to the first embodiment of the present invention, and shows a path of reflected light that is diffused by repeating internal reflection at an angle of 30 degrees in the outer peripheral direction of the disk.
  • FIG. 1B is a partially enlarged cross-sectional view showing a path of reflected light when the light is reflected at a critical angle (45 degrees) in the CD shown in FIG.
  • FIG. 1C is a partially enlarged cross-sectional view showing the path of reflected light when reflected at an angle (60 degrees) greater than the critical angle in CD shown in FIG.
  • FIG. 2A is a partially enlarged sectional view of a CD according to a first modification of the first embodiment of the present invention.
  • FIG. 2B is a partially enlarged sectional view of a CD according to a second modification of the first embodiment of the present invention.
  • FIG. 2C is a partially enlarged sectional view of a CD according to a third modification of the first embodiment of the present invention.
  • FIG. 2D is a partially enlarged sectional view of a CD according to a fourth modification of the first embodiment of the present invention.
  • FIG. 3A is a perspective view of a part of a CD according to a second embodiment of the present invention.
  • FIG. 3B is a perspective view of a part of a CD according to a modification of the second embodiment of the present invention.
  • FIG. 4 is a perspective view of a part of a CD according to a third embodiment of the present invention.
  • FIG. 5A is a plan view showing a part of a CD according to a fourth embodiment of the present invention.
  • FIG. 5B is a diagram showing a state of diffusion of reflected light by the through-hole shown in FIG. 5A.
  • FIG. 5C is a partially enlarged cross-sectional view showing a path of reflected light at a reflection angle equal to the critical angle in the CD shown in FIG. 5A.
  • Light has the property that part or most of it is reflected back at the interface of matter.
  • the percentage of light that is reflected back depends on the angle between the light incident on the interface and the interface.
  • the boundary surface ie, the boundary surface between the disk and air
  • the angle of incidence is small (if the angle is nearly perpendicular to the boundary surface)
  • most of the incident light is on the disk. Released outside.
  • the proportion of light reflected at the interface and back into the disk increases.
  • the angle of incidence further increases and exceeds the critical angle, light incident on the boundary surface is totally reflected.
  • the light generated by the irregular reflection of the laser beam inside the optical disk is diffused in the outer and inner circumferential directions while being repeatedly reflected on the upper and lower surfaces of the optical disk.
  • the reflected light traveling in the inner circumference direction is the inner edge of the optical disc. Reflect on the surface.
  • the inner end surface of the optical disk is a convex surface with respect to the reflected light, it is diffused and attenuated by reflection.
  • the outer edge of the optical disk is usually formed by a plane perpendicular to the upper and lower surfaces of the optical disk. Therefore, the reflected light traveling in the outer peripheral direction in the optical disc is reflected in the inner peripheral direction of the optical disc at the outer edge of the optical disc. The reflected light is repeatedly reflected on the upper and lower surfaces of the disk, is emitted from the optical disk while traveling in the inner circumferential direction, and may enter the optical pickup. This causes generation of digital noise, which affects reproduction sound quality or image quality.
  • the critical angle of an optical disc varies depending on its material, but is usually 40 to 50 degrees. Therefore, by making the angle between the outer edge of the optical disc and the upper or lower surface of the optical disk equal to or greater than the critical angle, the light incident on the outer edge can be efficiently emitted to the outside of the optical disc.
  • FIGS. 1A, 18 and 1 are partially enlarged longitudinal sectional views of an optical disc according to a first embodiment of the present invention.
  • Figures 1A, 18 and 1 show the state of internal reflection due to irregular reflection of the laser beam inside the optical disc.
  • the critical angle of the optical disk of this embodiment is 45 degrees. The critical angle varies depending on the material, but is about 40 to 50 degrees for a general optical disk.
  • This optical disk is a CD (compact disk) 1, and its outer edge 2 is inclined at an angle of 45 degrees with respect to the upper and lower surfaces of the disk.
  • a laser beam projected from an optical pickup enters the CD 1 and is reflected by a pit forming surface which is a signal recording portion in the disk.
  • the signal recorded on CD 1 is read based on the intensity of the reflected light.
  • One of the laser beams projected on CD 1 The part is diffusely reflected and diffuses toward the center and the outer periphery of the disk.
  • Such irregularly reflected light may be repeatedly reflected or refracted inside the disc and returned to the optical pickup. When the irregularly reflected light returned to the optical pickup is read as a signal, digital noise is generated.
  • the diffusely reflected light in the CD 1 is attenuated by diffusion.
  • reflected light that is totally reflected by reflection at a critical angle or more that is, scattered light that does not attenuate
  • light that is integrated by reflection at the outer edge 2 that is, scattered light that is widened
  • FIG. 1A shows the path of reflected light 3 that diffusely reflects inside CD 1 and diffuses by repeating internal reflection in the outer circumferential direction of the disc. Degree).
  • FIG. 1B shows the path of the reflected light 7 when reflected at the critical angle of CD 1 (45 degrees).
  • the reflection angle is equal to the critical angle
  • the reflected light 7 is totally reflected by the upper and lower surfaces 11 A and 11 B of the disk and reaches the outer edge 2 without attenuation. Since the incident angle of the reflected light 7 is perpendicular to the outer edge 2, all of the reflected light 7 is emitted from the outer edge 2 to the outside of the CD 1.
  • FIG. 1C shows the path of reflected light 8 when reflected at an angle (60 degrees) greater than the critical angle of CD 1.
  • the reflected light 8 Since the reflection angle is greater than the critical angle, the reflected light 8 The light is totally reflected by the upper and lower surfaces 11 A and 11 B of the disk and travels to the outer edge 2. Since the reflection angle at the outer edge 2 is within the critical angle, most of the reflected light 8 is emitted to the outside as refracted light 9. However, part of the reflected light 8 is reflected toward the center of the disk by the outer end face 2, and becomes reflected light 10. Since the reflected light 10 is sufficiently attenuated, it is very unlikely that the reflected light 10 will cause digital noise even if it is incident on the optical pickup.
  • the CD1 created in this way was played and three audiophiles listened to it. As a result, three people appraised that the sound quality was clearly improved from the conventional one.
  • the angle between the outer edge 2 of the CD 1 and the lower surface 11B is 45 degrees, but the angle between the outer edge 2 and the upper surface 11A of the CD 1 is 45 degrees. It may be.
  • the angle between the outer edge 2 and the lower surface 11B of the CD 1 is 45 degrees, but the present invention is not limited to this. That is, if the outer edge 2 of the CD 1 is inclined at an angle other than 90 degrees with respect to the lower surface 11B (or the upper surface 11A), the effect of the present invention can be obtained at all.
  • the radial length of the outer edge portion of a general optical disk that is, the portion where no signal is recorded, is usually l to 2 mm, and the thickness of the optical disk is usually 1.2 mm. Therefore, if the angle between the outer edge 2 and the lower surface of the CD 1 is set to 40 degrees or less, the area of the outer edge 2 increases, and the area of the recording area decreases, which is not preferable.
  • the outer edge 2 of the CD 1 preferably forms an angle with the lower surface (or the upper surface) of 40 degrees to 89 degrees.
  • FIG. 2A is a partially enlarged longitudinal sectional view of CD 1 according to a first modification of the first embodiment of the present invention.
  • FIG. 2A an internal reflection path due to irregular reflection of the laser beam inside the CD 1 is shown.
  • the critical angle of C D 1 is 45 degrees.
  • the outer edge 12 of the CD 1 shown in Fig. 2A has a surface extending at an angle of 135 degrees from the upper surface 11A of the disk and an angle of 135 degrees from the lower surface 11B. It is composed of planes. Therefore, the cross section of the outer edge end face 12 has a triangular top shape having a vertex angle of 45 degrees.
  • FIG. 2B is a partially enlarged longitudinal sectional view of CD 1 according to a second modification of the first embodiment of the present invention.
  • FIG. 2B shows an internal reflection path due to irregular reflection of the laser beam inside the CD 1.
  • the outer edge 14 of the CD 1 shown in FIG. 2B is formed in a semicircular shape. Therefore, in the CD 1 shown in FIG. 2B, the reflected light 13 that repeats reflection at an angle of 45 degrees equal to the critical angle is emitted to the outside of the CD 1 from the semicircular outer edge 14.
  • FIG. 2C is a partially enlarged longitudinal sectional view of CD 1 according to a third modification of the first embodiment of the present invention.
  • FIG. 2C shows an internal reflection path due to irregular reflection of the laser beam inside CD 1.
  • the outer edge 15 of CD 1 shown in Fig. 2C has a surface extending at an angle of 45 degrees from the upper surface 11A of the disk and a surface extending at an angle of 45 degrees from the lower surface 11B. It is configured.
  • FIG. 2D is a partially enlarged longitudinal sectional view of CD 1 according to a fourth modification of the first embodiment of the present invention.
  • the internal reflection path due to the irregular reflection of the laser beam inside CD 1 is shown.
  • the outer edge 16 of the CD 1 shown in FIG. 2D is formed in a concave curved shape.
  • reflected light 13 that repeats reflection at a reflection angle equal to the critical angle is emitted to the outside of CD 1 at the outer end face 16.
  • FIG. 3A is a perspective view of a part of a CD 1A according to a second embodiment of the present invention.
  • the CD 1A shown in FIG. 3A has a boundary layer 18 embedded inside the substrate 17 on the outer periphery of the disk.
  • the boundary layer 18 is formed by a thin ring made of glass, and is buried in an inclined manner so as to be non-perpendicular to the upper and lower surfaces 11 A and 11 B of the CD 1 A.
  • the ring forming the boundary layer 18 is integrally formed with the substrate 17 when the CD 1A is formed. Alternatively, the ring may be fitted after the formation of the CD 1A and bonded together with the outer peripheral portion.
  • the reflected light 19 with a reflection angle equal to the critical angle (45 degrees), which is a problem with the reflected light due to irregular reflection inside the optical disk, is the glass plate that is the boundary layer 18 At the surface of the ring, as shown in the figure, it is greatly refracted toward the upper surface of the disk and emitted outside the CD 1A.
  • a transparent dissimilar member 20 is formed on the outer periphery of the CD 1A shown in FIG. 3B.
  • the dissimilar member 20 is formed of a material different from the material of the substrate 17 of the CD 1 A, and the boundary surfaces 21 that are not perpendicular to the upper and lower surfaces 11 A and 11 B of the CD 1 A are formed. It is formed between the dissimilar member 20 and the substrate 17.
  • the dissimilar member 20 is a transparent material having a suitable strength.
  • the substrate 17 of the disk may be formed of acrylic, and the outer heterogeneous member 20 may be formed of polycarbonate.
  • the reflected light 22 due to internal irregular reflection is largely refracted at the boundary surface 21 between the dissimilar member 20 and the substrate 17 and is emitted to the outside of the CD 1A. Therefore, reflection toward the center of the disk can be suppressed.
  • FIG. 4 is a perspective view of a part of a CD 1 B according to a third embodiment of the present invention.
  • the CD 1B shown in FIG. 4 has an annular upper surface groove 23 on the upper surface 11A of the outer peripheral portion and an annular lower surface groove 24 on the lower surface 11B of the outer peripheral portion.
  • the upper surface groove 23 and the lower surface groove 24 are provided concentrically.
  • Each of the grooves 23 and 24 has a V-shaped cross section, and has a depth slightly larger than 1 Z 2 of the thickness of the disk.
  • the lower groove 24 is formed on the outer peripheral side of the upper groove 23.
  • the reflected light 25 and 26 due to irregular reflection generated inside the disk is refracted or reflected by the upper groove 23 and the lower groove 24. Released outside the disc.
  • the positions of the upper surface groove 23 and the lower surface groove 24 may be the same in the radial direction of the disk, but are preferably shifted as shown in the figure.
  • FIG. 5A is a plan view showing a part of a CD 1C according to a fourth embodiment of the present invention
  • FIG. 5B is a view showing a state of diffusion of reflected light by a through hole shown in FIG. 5A. Yes
  • FIG. 5C is a cross-sectional view showing the path of reflected light at a reflection angle equal to the critical angle.
  • the critical angle of C D 1 C is 45 degrees.
  • the CD 1C has a large number of through-holes 28 at the outer edge 27 at equal intervals on the circumference of the disk.
  • the through-holes 28 are arranged in two rows in double concentric circles, and are provided so as to be shifted so that the concentric through-holes 28 do not overlap.
  • the reflected light does not directly reach the outer end surface 29 of the CD 1C through the gap between the through hole 28 and the adjacent through hole 28.
  • the through hole 28 has a cylindrical shape with a hole diameter of 1 mm, and its axis is inclined by 15 degrees toward the center of the disk.
  • the interval between the concentric circles in which the through holes are arranged is 0.5 mm.
  • the reflected light 30 is dispersed and attenuated in the arrangement portion of the through holes 28, and hardly reflects toward the center of the disk.
  • the reflected light 31 at a reflection angle equal to the critical angle is refracted into the through-hole 28, enters the through-hole 28, passes through the through-hole 28 (transmitted light 32), and passes through as shown in FIG. 5C.
  • the light is reflected inside the hole 28 (reflected light 33) and emitted outside the CD 1C.
  • the through hole 28 is provided at the outer peripheral end.
  • the through hole may be provided at the inner peripheral end to attenuate the reflected light at the inner peripheral end. .
  • the laser beam reflected in the optical disc can be efficiently emitted to the outside of the optical disc at the outer edge or outer peripheral portion of the optical disc.

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  • Holding Or Fastening Of Disk On Rotational Shaft (AREA)
  • Optical Record Carriers And Manufacture Thereof (AREA)
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Abstract

La présente invention concerne un disque optique (1) dont une surface (2) de l'extrémité périphérique est formée en inclinaison par rapport aux faces supérieure et inférieure (11A, 11B). L'angle formé avec la face supérieure ou inférieure (11A, 11B) est défini dans les limites de 40° à 89°. La surface (2) de l'extrémité périphérique est admise à prendre une forme en coupe triangulaire ou incurvée. Les rayons de lumière réfléchis dans le disque optique (1) se déchargent de façon satisfaisante vers l'extérieur depuis la surface (2) de l'extrémité périphérique, sans être renvoyés vers une tête de lecture optique de façon à réduire le bruit numérique dans le signal de régénération.
PCT/JP1999/000882 1998-03-12 1999-02-25 Disque optique WO1999046770A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP10/82910 1998-03-12
JP8291098 1998-03-12
JP10193792A JPH11328727A (ja) 1998-03-12 1998-06-23 光ディスク及び光ディスク用リング
JP10/193792 1998-06-23

Publications (1)

Publication Number Publication Date
WO1999046770A1 true WO1999046770A1 (fr) 1999-09-16

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Family Applications (2)

Application Number Title Priority Date Filing Date
PCT/JP1999/000882 WO1999046770A1 (fr) 1998-03-12 1999-02-25 Disque optique
PCT/JP1999/000883 WO1999046771A1 (fr) 1998-03-12 1999-02-25 Disque optique et bague pour disque optique

Family Applications After (1)

Application Number Title Priority Date Filing Date
PCT/JP1999/000883 WO1999046771A1 (fr) 1998-03-12 1999-02-25 Disque optique et bague pour disque optique

Country Status (2)

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JP (1) JPH11328727A (fr)
WO (2) WO1999046770A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2377074A (en) * 2001-03-06 2002-12-31 Chieh-Ho Chen Compact disc having a circumferential edge shaped to prevent cutting a user's hand

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6562432B2 (en) 2000-09-29 2003-05-13 Ricoh Company, Ltd. Optical recording medium and method of manufacturing the optical recording medium
US6865745B2 (en) * 2001-08-10 2005-03-08 Wea Manufacturing, Inc. Methods and apparatus for reducing the shrinkage of an optical disc's clamp area and the resulting optical disc
JP7040932B2 (ja) 2017-12-19 2022-03-23 株式会社ダイヘン 溶接位置検出装置、溶接位置検出方法及び溶接ロボットシステム

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0547035A (ja) * 1991-08-15 1993-02-26 Japan Synthetic Rubber Co Ltd 光デイスク基板
JPH05138679A (ja) * 1991-11-20 1993-06-08 Matsushita Electric Ind Co Ltd 光デイスク用樹脂成形基材および金型
JPH06309701A (ja) * 1993-04-28 1994-11-04 Ricoh Co Ltd ディスク状記録媒体

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5712009U (fr) * 1980-06-24 1982-01-21
JPH0652060U (ja) * 1992-12-08 1994-07-15 九州日立マクセル株式会社 ディスク用ガードリング

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0547035A (ja) * 1991-08-15 1993-02-26 Japan Synthetic Rubber Co Ltd 光デイスク基板
JPH05138679A (ja) * 1991-11-20 1993-06-08 Matsushita Electric Ind Co Ltd 光デイスク用樹脂成形基材および金型
JPH06309701A (ja) * 1993-04-28 1994-11-04 Ricoh Co Ltd ディスク状記録媒体

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2377074A (en) * 2001-03-06 2002-12-31 Chieh-Ho Chen Compact disc having a circumferential edge shaped to prevent cutting a user's hand

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WO1999046771A1 (fr) 1999-09-16
JPH11328727A (ja) 1999-11-30

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