Methods for Bonding Substrates Using Liquid Adhesive

• US 20140246148A1
• Filed: 02/18/2014
• Published: 09/04/2014
• Est. Priority Date: 03/01/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Sung, Kuo-Hua, Chen, Po-Jui, Grespan, Silvio, Liu, Cyrus Y.
• Granted Patent: US 9,494,178 B2
• Time in Patent Office: Days
• US Class Current: 156/275.5
• CPC Class Codes: B32B 2457/00 Electrical equipment
• CPC Class Codes: B32B 2457/20 Displays, e.g. liquid crystal displays, plasma displays
• CPC Class Codes: B32B 5/26 another layer next to it also being fibrous or filamentary relative arrangement of fibres or filaments of different layers B32B5/12
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: C09J 2301/416 use of irradiation
• CPC Class Codes: C09J 5/00 Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers
• CPC Class Codes: F16B 11/006 by gluing gluing of plastics material B29C65/48
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor

Abstract

Structures in an electronic device such as substrates associated with a display may be bonded together using liquid adhesive. Fiber-based equipment may be used to apply ultraviolet light to peripheral edges of an adhesive layer during bonding. There-dimensional adhesive shapes may be produced using nozzles with adjustable openings, computer-controlled positioners, and other adhesive dispensing equipment. Ultraviolet light may be applied to liquid adhesive through a mask with an opacity gradient. Adjustable shutter structures may control adhesive exposure to ultraviolet light. Ultraviolet light exposure may be used to create an adhesive dam that helps create a well defined adhesive border. Multiple layers of adhesive may be applied between a pair of substrates.

Claims

1. A method for bonding substrates, comprising:

applying liquid adhesive to at least one of the substrates; and

applying ultraviolet light to an edge of the liquid adhesive using fiber-based equipment.

2. The method defined in claim 1 wherein the fiber-based equipment includes a fiber bundle containing a strip of fibers and wherein applying the ultraviolet light comprises applying the ultraviolet light using the strip of fibers.

3. The method defined in claim 2 wherein the fiber bundle contains side-firing fibers and wherein applying the ultraviolet light comprises applying the ultraviolet light at a right angle relative to a longitudinal axis of at least one of the fibers.

4. The method defined in claim 2 wherein each fiber in the fiber bundle emits light, the method further comprising individually controlling the light emitted by each fiber.

5. The method defined in claim 4 wherein individually controlling the light comprises using light modulators in fiber paths associated with the fibers to modulate how much of the light is emitted from each fiber.

6. The method defined in claim 4 wherein individually controlling the light comprises individually controlling each of a plurality of light-emitting diodes.

7. The method defined in claim 1 wherein the substrates comprise display substrates for an electronic device display and wherein applying the adhesive comprises applying the adhesive to at least one of the display substrates.

8. The method defined in claim 7 wherein the display substrates include a polarizer layer and wherein applying the adhesive comprises applying the adhesive to the polarizer layer.

9. The method defined in claim 7 wherein the display substrates include a display cover glass layer and wherein applying the adhesive comprises applying the adhesive to the display cover glass layer.

10. A method for bonding substrates together, comprising:

dispensing liquid adhesive onto at least one of the substrates through an opening with a triangular portion; and

pressing together the substrates so that the adhesive flows to cover the substrates.

11. The method defined in claim 10 wherein dispensing the liquid adhesive further comprises controlling a relative speed between the opening and the at least one substrate using a computer-controlled positioner.

12. The method defined in claim 11 wherein dispensing the liquid adhesive comprises dispensing the liquid adhesive through a plurality of openings.

13. The method defined in claim 12 further comprising:

using valves to individually control adhesive flow through each of the plurality of openings.

14. A method for bonding substrates, comprising:

applying liquid adhesive to at least one of the substrates;

applying ultraviolet light to the liquid adhesive through a mask; and

bonding the substrates together using the liquid adhesive to which the ultraviolet light has been applied.

15. The method defined in claim 14 wherein the mask includes at least one portion with an opacity gradient and wherein the applying the ultraviolet light comprises applying the ultraviolet light through the portion of the mask with the opacity gradient.

16. The method defined in claim 15 wherein applying the ultraviolet light comprises curing a rectangular ring of the adhesive to create an adhesive dam having a outer edge and having an inner edge that is less abrupt than the outer edge.

17. The method defined in claim 16 wherein the adhesive dam comprises a rectangular ring, the method further comprising applying liquid adhesive to the substrate that is contained by the rectangular ring before bonding the substrates together.

18. A method for bonding substrates, comprising:

applying liquid adhesive to at least one of the substrates;

applying ultraviolet light to the liquid adhesive while blocking at least some of the ultraviolet light with a shutter; and

bonding the substrates together after applying the ultraviolet light to the liquid adhesive.

19. The method defined in claim 18 wherein the shutter has a size and wherein applying the ultraviolet light comprises adjusting the size of the shutter while applying the ultraviolet light.

20. The method defined in claim 19 wherein applying the ultraviolet light comprises applying the ultraviolet light in a rectangular ring shape to form a rectangular-ring-shaped adhesive dam.

21. The method defined in claim 20 further comprising:

applying additional liquid adhesive to the substrate that is confined by the adhesive dam.

22. The method defined in claim 21 wherein the shutter comprises movable blades and wherein adjusting the size of the shutter comprises moving the blades.

23. A method for bonding first and second substrates, comprising:

applying a layer of a first liquid adhesive to the first substrate;

applying a layer of a second liquid adhesive that is different than the first liquid adhesive to the first liquid adhesive; and

bonding the first and second substrates together using at least the first and second layers of adhesive.

24. The method defined in claim 23 wherein the first and second substrates comprise display substrates and wherein the first and second liquid adhesives comprise liquid optically clear adhesives.

25. The method defined in claim 24 wherein bonding the first and second substrates together comprises curing the first and second liquid adhesives so that the second liquid adhesive is harder than the first liquid adhesive.