Display device substrate and display device formed therewith

• US 20030077453A1
• Filed: 03/20/2002
• Published: 04/24/2003
• Est. Priority Date: 10/18/2001
• Status: Active Grant

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Oaku, Hitoshi, Amagi, Shigeo, Oishi, Tomoji, Kondou, Katsumi, Hanawa, Yasuo
• Granted Patent: US 6,660,387 B2
• Time in Patent Office: Days
• US Class Current: 428/415
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10211 Doped dielectric layer, electrically conductive, e.g. SnO2:F
• CPC Class Codes: B32B 17/10733 containing epoxy
• CPC Class Codes: B32B 17/1077 containing polyurethane
• CPC Class Codes: G02F 1/133302 Rigid substrates, e.g. inorganic substrates
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31515 As intermediate layer
• CPC Class Codes: Y10T 428/31518 Next to glass or quartz
• CPC Class Codes: Y10T 428/31652 Of asbestos
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

A display device substrate which meets requirements for weight reduction, thickness reduction, high reliability, good heat resistance, and good impact resistance all at one once. The display device substrate is composed of a pair of glass sheets facing each other and a layer of plastics material interposed between said paired glass sheets in such a way that said glass sheets have an internal compressive strain ascribed to the plastic sheet. Thus, the very thin glass sheets are hardly liable to breakage. This makes light weight and reduced thickness compatible with reliability.

Claims

1. An improved display device substrate which is composed of a pair of glass sheets facing each other and a layer of plastics material interposed between said paired glass sheets, wherein said improvement comprises said glass sheets having an internal compressive strain.

2. The display device substrate as defined in claim 1, wherein said glass sheets have an internal compressive strain ascribed to the layer of plastics material interposed between them.

3. The display device substrate as defined in claim 1 or 2, wherein said layer of plastics material is that of a thermosetting resin excluding polyurethane.

4. The display device substrate as defined in any one of claims 1 to 3, wherein said layer of plastics material is that of epoxy resin.

5. The display device substrate as defined in any one of claims 1 to 4, wherein said layer of plastics material is that of inorganic-organic hybrid material.

6. The display device substrate as defined in any one of claims 1 to 5, wherein said layer of plastics material is that of epoxy-silicone-based inorganic-organic hybrid material.

7. The display device substrate as defined in any one of claims 1 to 6, wherein said layer of plastics material is that of epoxy-silicone-based inorganic-organic hybrid material synthesized from an epoxy resin and an organosilicon compound.

8. The display device substrate as defined in any one of claims 1 to 7, wherein said layer of plastics material is that of inorganic-organic hybrid material synthesized from an epoxy-type organosilicon alkoxide represented by the chemical formula (1) below.

9. The display device substrate as defined in any one of claims 1 to 8, wherein said layer of plastics material is that of inorganic-organic hybrid material synthesized from any of epoxy resin of glycidyl ether type composed mainly of a phenolic compound such as bisphenol-A, bisphenol-F, tetrabromobisphenol-A, tetraphenylolethane, phenol-novolak, and o-cresol-novolak;

epoxy resin of glycidyl ether type composed mainly of an alcoholic compound such as polypropylene glycol and hydrogenated bisphenol-A;

epoxy resin of glycidyl ester type composed mainly of hexahydrophthalic anhydride or dimmer acid;

epoxy resin of glycidyl amine type composed mainly of diaminophenylmethane, isocyanuric acid, or hydantoin;

epoxy resin of mixed type composed mainly of p-aminophenol or p-oxybenzoic acid; and

epoxy resin composed mainly of an ester represented by the chemical formula (2) below.

10. The display device substrate as defined in any one of claims 6 to 9, wherein said layer of plastics material contains a silicon component (in terms of SiO₂) in an amount more than 0 wt % and less than 30 wt %.

11. The display device substrate as defined in any one of claims 6 to 9, wherein said layer of plastics material contains a silicon component (in terms of SiO₂) in an amount more than 4 wt % and less than 15 wt %.

12. The display device substrate as defined in any one of claims 1 to 11, wherein said glass sheets have an internal compressive strain no less than 1.9×

10<sup>−

4</sup>.

13. The display device substrate as defined in any one of claims 1 to 12, which has a thickness no larger than 0.3 mm.

14. The display device substrate as defined in any one of claims 1 to 13, which satisfies the relation represented by the mathematical expression (1) below.

|{(α

g−

α

r)×

Δ

T×

(Er×

hr)}/{(Er×

hr)+(Eg×

hg)}|≧

1.9×

10<sup>−

4</sup> 

 

(1)

(where Δ

T denotes a difference between the operating temperature of the display device substrate and the glass transition point (Tg) of the plastics material or the maximum temperature to be reached by the plastics material during its curing or molding if the latter is lower than the former.)

α

g=coefficient of linear expansion of glass used

α

r=coefficient of linear expansion of plastics material

Eg=elastic modulus of glass

Er=elastic modulus of plastics material

hg=total thickness of glass sheets

hr=thickness of plastics material

15. The display device substrate as defined in any one of claims 1 to 13, which satisfies the relation represented by the mathematical expression (2) below.

{α

r×

Δ

T×

(Er×

hr)}/{Eg×

hg}≧

1.9×

10<sup>−

4</sup> 

 

(2)

16. The display device substrate as defined in claim 15, wherein said glass sheets have a total thickness no smaller than 60 μ

m.

17. The display device substrate as defined in claim 15, wherein said glass sheets have a total thickness no smaller than 100 μ

m.

18. The display device substrate as defined in claim 15, wherein said glass sheets have a total thickness no smaller than 140 μ

m.

19. The display device substrate as defined in any one of claims 1 to 13, which satisfies the relation represented by the mathematical expression (3) below.

{α

r×

Δ

T×

(Er×

hr)}≧

2800 Pa·

m (Pascal-meter) 

 

(3)

20. The display device substrate as defined in any one of claims 1 to 19, which satisfies the relation represented by the mathematical expression (4) below.

(α

r×

Δ

T×

hr)≧

1.4×

10<sup>−

6</sup> m 

 

(4)

21. The display device substrate as defined in any one of claims 1 to 13, wherein said glass sheets have a total thickness no larger than 150 μ

m and the display device substrate satisfies the relation represented by the mathematical expression (5) below.

{α

r×

Δ

T×

(Er×

hr)}≧

2100 Pa·

m 

 

(5)

22. The display device substrate as defined in any one of claims 1 to 13, wherein said glass sheets have a total thickness no larger than 100 μ

m and the display device substrate satisfies the relation represented by the mathematical expression (6) below.

{α

r×

Δ

T×

(Er×

hr)}≧

1400 Pa·

m 

 

(6)

23. The display device substrate as defined in any one of claims 14 to 22, wherein the maximum temperature to be reached by the plastics material during its curing or molding is lower than its glass transition point (Tg) and Δ

T is a difference between the operating temperature of the display device substrate and the maximum temperature to be reached by the plastics material during its curing or molding.

24. The display device substrate as defined in any one of claims 1 to 11, wherein said glass sheets have an internal compressive strain no smaller than 3.4×

10<sup>−

4</sup>.

25. The display device substrate as defined in claim 24, which has a thickness no larger than 0.3 mm.

26. The display device substrate as defined in claim 24 or 25, which satisfies the relation represented by the mathematical expression (7) below.

|{(α

g−

α

r)×

Δ

T×

(Er×

hr)}/{(Er×

hr)+(Eg×

hg)}|≧

3.4×

10<sup>−

4</sup> 

 

(7)

(where Δ

T denotes a difference between the operating temperature of the display device substrate and the glass transition point (Tg) of the plastics material or the maximum temperature to be reached by the plastics material during its curing or molding if the latter is lower than the former.)

α

g=coefficient of linear expansion of glass used

α

r=coefficient of linear expansion of plastics material

Eg=elastic modulus of glass

Er=elastic modulus of plastics material

hg=total thickness of glass sheets

hr=thickness of plastics material

27. The display device substrate as defined in claim 24 or 25, which satisfies the relation represented by the mathematical expression (8) below.

{α

r×

Δ

T×

(Er×

hr)}/{Eg×

hg}≧

3.4×

10<sup>−

4</sup> 

 

(8)

28. The display device substrate as defined in claim 27, wherein said glass sheets have a total thickness no smaller than 100 μ

m.

29. The display device substrate as defined in claim 27, wherein said glass sheets have a total thickness no smaller than 140 μ

m.

30. The display device substrate as defined in claim 24 or 25, wherein said glass sheets have a total thickness no larger than 140 μ

m and the display device substrate satisfies the relation represented by the mathematical expression (9) below.

{α

r×

Δ

T×

(Er×

hr)}≧

3500 Pa·

m 

 

(9)

31. The display device substrate as defined in claim 24 or 25, wherein said glass sheets have a total thickness no larger than 140 μ

m and the display device substrate satisfies the relation represented by the mathematical expression (10) below.

(α

r×

Δ

T×

hr)≧

1.7×

10<sup>−

6</sup> m 

 

(10)

32. The display device substrate as defined in claim 24 or 25, wherein said glass sheets have a total thickness no larger than 100 μ

m and the display device substrate satisfies the relation represented by the mathematical expression (11) below.

{α

r×

Δ

T×

(Er×

hr)}≧

2500 Pa·

m 

 

(11)

33. The display device substrate as defined in claim 24 or 25, wherein said glass sheets have a total thickness no larger than 100 μ

m and the display device substrate satisfies the relation represented by the mathematical expression (12) below.

(α

r×

Δ

T×

hr)≧

1.2×

10<sup>−

6</sup> m 

 

(12)

34. The display device substrate as defined in any one of claims 26 to 33, wherein the maximum temperature to be reached by the plastics material during its curing or molding is lower than its glass transition point (Tg) and Δ

T is a difference between the operating temperature of the display device substrate and the maximum temperature to be reached by the plastics material during its curing or molding.

35. The display device substrate as defined in any one of claims 1 to 11, which has a thickness no larger than 0.2 mm and wherein said glass sheets have an internal compressive strain no smaller than 3.4×

10<sup>−

4</sup>.

36. The display device substrate as defined in claim 35, which satisfies the relation represented by the mathematical expression (13) below.

|{(α

g−

α

r)×

Δ

T×

(Er×

hr)}/{(Er×

hr)+(Eg×

hg)}|≧

3.4×

10<sup>−

4</sup> 

 

(13)

(where Δ

T denotes a difference between the operating temperature of the display device substrate and the glass transition point (Tg) of the plastics material or the maximum temperature to be reached by the plastics material during its curing or molding if the latter is lower than the former.)

α

g=coefficient of linear expansion of glass used

α

r=coefficient of linear expansion of plastics material

Eg=elastic modulus of glass

Er=elastic modulus of plastics material

hg=total thickness of glass sheets

hr=thickness of plastics material

37. The display device substrate as defined in claim 35, which satisfies the relation represented by the mathematical expression (14) below.

{α

r×

Δ

T×

(Er×

hr)}/{Eg×

hg}≧

3.4×

10<sup>−

4</sup> 

 

(14)

38. The display device substrate as defined in claim 37, wherein said glass sheets have a total thickness no smaller than 100 μ

m.

39. The display device substrate as defined in claim 35, wherein said glass sheets have a total thickness no larger than 100 μ

m and the display device substrate satisfies the relation represented by the mathematical expression (15) below.

{α

r×

Δ

T×

(Er×

hr)}≧

2500 Pa·

m 

 

(15)

40. The display device substrate as defined in claim 35, wherein said glass sheets have a total thickness no larger than 100 μ

m and the display device substrate satisfies the relation represented by the mathematical expression (16) below.

(α

r×

Δ

T×

hr)≧

1.2×

10<sup>−

6</sup> m 

 

(16)

41. The display device substrate as defined in any one of claims 35 to 40, wherein the maximum temperature to be reached by the plastics material during its curing or molding is lower than its glass transition point (Tg) and Δ

T is a difference between the operating temperature of the display device substrate and the maximum temperature to be reached by the plastics material during its curing or molding.

42. The display device substrate as defined in any one of claims 1 to 11, wherein said glass sheets have an internal compressive strain no smaller than 5.0×

10<sup>−

4</sup>.

43. The display device substrate as defined in claim 42, which has a thickness no larger than 0.3 mm.

44. The display device substrate as defined in claim 42 or 43, which satisfies the relation represented by the mathematical expression (17) below.

|{(α

g−

α

r)×

Δ

T×

(Er×

hr)}/{(Er×

hr)+(Eg×

hg)}|≧

5.0×

10<sup>−

4</sup> 

 

(17)

(where Δ

T denotes a difference between the operating temperature of the display device substrate and the glass transition point (Tg) of the plastics material or the maximum temperature to be reached by the plastics material during its curing or molding if the latter is lower than the former.)

α

g=coefficient of linear expansion of glass used

α

r=coefficient of linear expansion of plastics material

Eg=elastic modulus of glass

Er=elastic modulus of plastics material

hg=total thickness of glass sheets

hr=thickness of plastics material

45. The display device substrate as defined in claim 44, wherein said glass sheets have a total thickness no smaller than 100 μ

m.

46. The display device substrate as defined in claim 44, wherein said glass sheets have a total thickness no smaller than 140 μ

m.

47. A display device which is formed with at least one piece of the display device substrate defined in nay of claims 1 to 46.