METHOD AND APPARATUS FOR BONDING OPTICAL DISC SUBSTRATES TOGETHER, AND METHOD FOR SUPPLYING LIQUID MATERIAL

• US 20080283192A1
• Filed: 09/17/2007
• Published: 11/20/2008
• Est. Priority Date: 04/27/2000
• Status: Abandoned Application

• Current Assignee: Origin Electric Company Limited
• Original Assignee: Origin Electric Company Limited
• Inventors: Nakamura, Masahiro, Kobayashi, Hideo, Shinohara, Shinichi, Kaji, Kanya
• Application Number:
  US11/856,199
• Publication Number:
  US 20080283192A1
• Time in Patent Office: Days
• US Class Current: 156/380.2
• CPC Class Codes: B29C 65/04 Dielectric heating, e.g. high-frequency welding , i.e. radio frequency welding of plastic materials having dielectric properties, e.g. PVC
• CPC Class Codes: B29C 65/483 Reactive adhesives, e.g. chemically curing adhesives
• CPC Class Codes: B29C 65/521 by spin coating
• CPC Class Codes: B29C 65/524 by applying the adhesive from an outlet device in contact with, or almost in contact with, the surface of the part to be joined
• CPC Class Codes: B29C 65/7811 for centring purposes
• CPC Class Codes: B29C 65/7847 using vacuum to hold at least one of the parts to be joined vacuum work holders in general B25B11/005
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/21 said joint lines being formed by a single dot or dash or by several dots or dashes, i.e. spot joining or spot welding
• CPC Class Codes: B29C 66/342 Preventing air-inclusions
• CPC Class Codes: B29C 66/452 the article having a disc form, e.g. making CDs or DVDs
• CPC Class Codes: B29C 66/723 being multi-layered B29C66/7292, B29C66/72941 take precedence
• CPC Class Codes: B29C 66/8242 Pneumatic or hydraulic drives using fluid pressure directly acting on the parts to be joined B29C66/8266
• CPC Class Codes: B29C 66/8322 Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29D 17/005 Producing optically read record carriers, e.g. optical discs
• CPC Class Codes: B29L 2017/005 CD''s, DVD''s
• CPC Class Codes: B32B 2429/02 Records or discs
• CPC Class Codes: B32B 37/003 to avoid air inclusion
• CPC Class Codes: B32B 37/1284 Application of adhesive
• CPC Class Codes: G11B 7/26 Apparatus or processes specially adapted for the manufacture of record carriers

Abstract

The object of the present invention is to significantly inhibit the formation of voids between substrates bonded together when a liquid adhesive is supplied onto an optical disc substrate or when the optical disc substrate is bonded to another optical disc substrate. Accordingly, the present invention discloses a method for bonding two optical disc substrates together which comprises the steps of joining the optical disc substrates together with an adhesive and curing the adhesive, wherein the adhesive is supplied onto the optical disc substrate by an electric field formed between the adhesive-supplying nozzle, for supplying the adhesive onto the optical disc substrate, and the optical disc substrate, and the two optical disc substrates are then joined together and subjected to spun by a spinning process.

Claims

1. An apparatus for bonding two optical disc substrates together by joining the optical disc substrates together with an adhesive which is liquid and by curing the adhesive, which comprises an adhesive-supplying nozzle which supplies the adhesive onto at least one of the optical disc substrates, and is a first electrode, an adhesive storage tank which stores the adhesive, and supplies the adhesive to the adhesive-supplying nozzle, an electrode means which is a second electrode and is placed in contact with or in the vicinity of the surface of the optical disc substrate which is opposite to the surface which faces the adhesive-supplying nozzle, an electric power supply for generating an electric field between the electrode means and the adhesive-supplying nozzle, and a joining apparatus for joining one of the optical disc substrates, onto at least one of which the adhesive is supplied, and another one of the optical disc substrates, wherein the adhesive-supplying nozzle is connected to a terminal of the electric power supply and a ground potential, and the electrode means is connected to another terminal of the electric power supply.

2. The apparatus according to claim 1, wherein the adhesive-supplying nozzle comprises a single nozzle or two nozzles placed separated from each other by almost 180 degrees away from each other, is placed over the optical disc substrate nearly perpendicular thereto with its tip(s) pointing downward, and forms a ring-shaped adhesive liquid film on the optical disc substrate which rotates relative to the nozzle(s).

3. The apparatus according to claim 1, wherein the adhesive-supplying nozzle comprises a plurality of nozzles placed at an approximately uniform spacing in a circular shape, is placed under the optical disc substrate nearly perpendicular thereto with their tips pointing upward, and supplies dot-shaped adhesive liquid films onto the underside of the optical disc substrate.

4. The apparatus according to claim 1, wherein the electric power supply generates an alternating-current electric field.

5. The apparatus according to claim 2, wherein the electric power supply generates an alternating-current electric field.

6. The apparatus according to claim 3, wherein the electric power supply generates an alternating-current electric field.

7. The apparatus according to claim 1, wherein the electric power supply generates a direct-current electric field.

8. The apparatus according to claim 2, wherein the electric power supply generates a direct-current electric field.

9. The apparatus according to claim 3, wherein the electric power supply generates a direct-current electric field.

10. The apparatus according to claim 1, wherein the electric power supply generates the electric field between the electrode means and the adhesive-supplying nozzle, so as to taper an end of a liquid film of the adhesive which is supplied by the adhesive-supplying nozzle toward the optical disc substrate in order to reduce an initial contact area between said end of the liquid film of the adhesive and the optical disc substrate for preventing generation of voids in said adhesive.

11. The apparatus according to claim 1, comprising:

a device for forming an electric field between said two optical disc substrates, wherein

an end of a liquid film of said adhesive which is supplied onto one of said optical disc substrates tapers, thereby making a contact area between said end of said liquid film and the other of said optical disc substrates which is opposed to said end smaller by an effect of said electric field, and generation of voids in said liquid film is prevented.

12. The apparatus according to claim 1, comprising:

a device for forming an electric field between said two optical disc substrates, wherein

an end of a liquid film of said adhesive which is supplied onto one of said optical disc substrates tapers, thereby making a contact area between said end of said liquid film and other liquid film of said adhesive which is supplied onto the other of said optical disc substrates and is opposed to said end smaller by an effect of said electric field, and generation of voids in said liquid film is prevented.

13. The apparatus according to claim 1, further comprising a lower support mounting one of the optical disc substrates onto at least one of which the adhesive is supplied, an upper support which is opposed to the lower support and mounts another one of the optical disc substrates, and a lifting member making the lower support move upward in order to allow a spacing between the optical disc substrates to become smaller.

14. The apparatus according to claim 1, wherein the apparatus is adapted to perform a spinning process on the optical disc substrates joined by the joining apparatus.

15. The apparatus according to claim 1, wherein the adhesive supplying nozzle is adapted to supply the adhesive onto an optical disc substrate which is being rotated.

16. The apparatus according to claim 1, wherein the apparatus is configured such that, at a time when the adhesive supplying nozzle supplies the adhesive onto the optical disc substrate, the adhesive-supplying nozzle is being rotated.