Glass roll and process for producing glass roll
Provided is a glass roll formed by winding a glass film into a roll, in which a minimum winding radius of the glass film is optimized. Thus, the glass film is reliably prevented from breaking due to static fatigue, and is able to be stored for long periods. A glass roll ( 1 ), which is formed by winding a glass film ( 2 ) into a roll, has a configuration in which the glass film has a minimum winding radius (R) satisfying the following relation: R≧(T/2)[(2.3/σ)×E−1], where σ represents flexural strength of the glass film ( 2 ) obtained by a 3-point bending test, T represents a thickness of the glass film, and E represents a Young's modulus of the glass film.
1. A glass roll, which is formed by winding a glass film into a roll,
wherein the glass film has a minimum winding radius (R) satisfying the following relation:
R
≥
T
2
(
2.3
σ
E
-
1
)
[
Formula
1
]
where σ represents flexural strength of the glass film obtained by a 3-point bending test, T represents a thickness of the glass film, and E represents a Young's modulus of the glass film.
2. The glass roll according to claim 1 , wherein the glass film has a thickness of 1 μm or more and 200 μm or less.
3. The glass roll according to claim 1 , wherein each end surface in a width direction of the glass film includes a cut surface which is cut by laser splitting.
4. The glass roll according to claim 1 , wherein the glass film is wound into a roll while being superposed on a protective sheet.
5. The glass roll according to claim 1 , wherein the glass film is formed by a downdraw method.
6. A manufacturing method for a glass roll which is formed by winding a glass film into a roll, the manufacturing method comprising winding the glass film so that a minimum winding radius (R) of the glass film satisfies the following relation:
R
≥
T
2
(
2.3
σ
E
-
1
)
[
Formula
2
]
where σ represents flexural strength of the glass film obtained by a 3-point bending test, T represents a thickness of the glass film, and E represents a Young's modulus of the glass film.