Glass plate structure, diaphragm, and opening member

1. A glass sheet composite comprising: two or more sheets; and an intermediate layer between at least a pair of the sheets, wherein

at least one of the pair of sheets is a glass sheet,

the intermediate layer satisfies all of the following properties (1) to (3), and

the glass sheet composite has a loss coefficient at 25° C. of 0.01 or more, and a sheet-thickness-direction longitudinal wave acoustic velocity of 4.0×10 3 m/s or more,

(1) the intermediate layer has a thickness of 20 μm or less,

(2) a compressive shear storage modulus at a temperature of 25° C. is 1.0×10 4 Pa or less, and

(3) at the temperature of 25° C. and 1 Hz, the compressive shear storage modulus is higher than a compressive shear loss modulus.

2. The glass sheet composite according to claim 1 , wherein

all of the pair of sheets are glass sheets, and

the glass sheet composite has the loss coefficient at 25° C. of 0.01 or more, and the sheet-thickness-direction longitudinal wave acoustic velocity of 5.0×10 3 m/s or more.

3. The glass sheet composite according to claim 1 , wherein

a total thickness of the pair of sheets is 1.0 mm or more, and

the intermediate layer and the sheets satisfy the following Formula A:

0<(thickness of intermediate layer [mm]/total thickness of the pair of sheets [mm])×(compressive shear storage modulus of intermediate layer material [Pa]/mean Young's modulus of the pair of sheets [Pa])≤1.0×10 −10   (A).

4. The glass sheet composite according to claim 1 , wherein the pair of sheets have a mean Young's modulus of 20 GPa or more at 25° C.

5. The glass sheet composite according to claim 1 , wherein a product of a total thickness of the pair of sheets and a mean Young's modulus of the pair of sheets is 2.0×10 7 Pa·m or more.

6. The glass sheet composite according to claim 1 , wherein a value obtained by dividing the thickness of the intermediate layer by a total thickness of the pair of sheets is 0.02 or less.

7. The glass sheet composite according to claim 1 , wherein a value obtained by dividing the compressive shear storage modulus of an intermediate layer material by a mean Young's modulus of the pair of sheets is 1×10 4 or less.

8. The glass sheet composite according to claim 1 , wherein a value obtained by dividing a mass of one sheet A of the pair of sheets by a mass of the other sheet B of the pair of sheets is 0.8 to 1.25.

9. The glass sheet composite according to claim 1 , wherein at least one of the pair of sheets has a loss coefficient at 25° C. of 1×10 −4 or more.

10. The glass sheet composite according to claim 1 , wherein at least one of the pair of sheets has a sheet-thickness-direction longitudinal wave acoustic velocity of 4.0×10 3 m/s or more.

11. The glass sheet composite according to claim 1 , comprising a sliding layer provided on a surface of the pair of sheets that is in contact with the intermediate layer.

12. The glass sheet composite according to claim 1 , wherein the glass sheet has a specific gravity of 2.8 or less.

13. The glass sheet composite according to claim 1 , wherein the glass sheet has a specific elastic modulus of 2.5×10 7 m 2 /s 2 or more.

14. The glass sheet composite according to claim 1 , wherein a difference between a refractive index of the intermediate layer and a refractive index of the pair of sheets in contact with the intermediate layer is 0.3 or less.

15. The glass sheet composite according to claim 1 , which has a curved surface shape.

16. A diaphragm comprising: the glass sheet composite according to claim 1 ; and at least one vibrator disposed on one surface or both surfaces of the glass sheet composite.

17. An opening member using the glass sheet composite according to claim 1 .

18. An opening member using the diaphragm according to claim 16 .