LAMINATED PLATE, AND METHOD OF PRODUCING LAMINATED PLATE

1 . A laminated plate comprising:

a first plate having a curved shape;

a second plate having a shape following the first plate; and

an intermediate film for bonding the first plate and the second plate,

wherein the first plate includes a first main surface arranged at a side opposite to the intermediate film, and a second main surface that contacts the intermediate film, the first plate having higher bending stiffness, compared to the second plate,

wherein the second plate is a glass plate having a third main surface that contacts the intermediate film, and a fourth main surface arranged at a side opposite to the intermediate film,

wherein, when, among cross sections including a normal line at a centroid of the first main surface, a cross section in which a radius of curvature of the first main surface becomes a maximum is a transverse section, and a cross section perpendicular to the transverse section is a longitudinal section, upon the bonding by the intermediate film being released, a radius of curvature of the second main surface is smaller than a radius of curvature of the third main surface both in a cross section corresponding to the transverse section and in a cross section corresponding to the longitudinal section, and

wherein a maximum value of bending compressive stress at an outer peripheral portion of the fourth main surface is less than or equal to 100 MPa.

2 . The laminated plate according to claim 1 , wherein the maximum value of the bending compressive stress is less than or equal to 90 MPa.

3 . The laminated plate according to claim 2 , wherein the maximum value of the bending compressive stress is less than or equal to 80 MPa.

4 . The laminated plate according to claim 1 , wherein the maximum value of the bending compressive stress is greater than or equal to 10 MPa.

5 . The laminated plate according to claim 4 , wherein the maximum value of the bending compressive stress is greater than or equal to 15 MPa.

6 . A laminated plate comprising:

a first plate having a curved shape;

a second plate having a shape following the first plate; and

an intermediate film for bonding the first plate and the second plate,

wherein the first plate includes a first main surface arranged at a side opposite to the intermediate film, and a second main surface that contacts the intermediate film, the first plate having higher bending stiffness, compared to the second plate,

wherein the second plate is a glass plate having a third main surface that contacts the intermediate film, and a fourth main surface arranged at a side opposite to the intermediate film,

wherein, when, among cross sections including a normal line at a centroid of the first main surface, a cross section in which a radius of curvature of the first main surface becomes a maximum is a transverse section, and a cross section perpendicular to the transverse section is a longitudinal section, upon the bonding by the intermediate film being released, a radius of curvature of the second main surface is smaller than a radius of curvature of the third main surface both in a cross section corresponding to the transverse section and in a cross section corresponding to the longitudinal section,

wherein, when a radius of curvature (mm) of the first main surface in the transverse section is x, and a radius of curvature of the first main surface in the longitudinal section is y, following formulas (1) through (3) are satisfied:

x≦ 1×10 6   (1),

y≦ 1×10 5   (2), and

y≧ax b   (3), and

wherein, in the formula (3), a is a coefficient; b is an exponent with a base of x; if x is greater than or equal to 2×10 2 and less than 5×10 2 , a is 6.06×10 10 and b is −2.51; if x is greater than or equal to 5×10 2 and less than 1×10 4 , a is 1.44×10 7 and b is −1.17; if x is greater than or equal to 1×10 4 and less than 1×10 5 , a is 2.43×10 4 and b is −4.77×10 −1 ; and if x is greater than or equal to 1×10 5 and less than or equal to 1×10 6 , a is 1.00×10 2 and b is 0.

7 . The laminated plate according to claim 6 , wherein a following formula is further satisfied:

y≧cx 4 ,

wherein, in the formula, c is a coefficient and d is an exponent with a base of x; if x is greater than or equal to 3×10 2 and less than 7×10 2 , c is 5.39×10 11 and d is −2.72; if x is greater than or equal to 7×10 2 and less than 1×10 4 , c is 2.78×10 7 and d is −1.21; if x is greater than or equal to 1×10 4 and less than 1×10 5 , c is 1.26×10 3 and d is −1.25×10 −1 ; and if x is greater than or equal to 1×10 5 and less than or equal to 1×10 6 , c is 2.99×10 2 and d is 0.

8 . The laminated plate according to claim 7 , wherein a following formula is further satisfied:

y≧ex f ,

wherein, in the formula, e is a coefficient and f is an exponent with a base of x; if x is greater than or equal to 5×10 2 and less than 9×10 2 , e is 3.74×10 15 and f is −3.92; if x is greater than or equal to 9×10 2 and less than 1×10 4 , e is 2.83×10 7 and f is −1.17; if x is greater than or equal to 1×10 4 and less than 1×10 5 , e is 1.24×10 3 and f is −7.92×10 −2 ; and if x is greater than or equal to 1×10 5 and less than or equal to 1×10 6 , e is 4.98×10 2 and f is 0.

9 . The laminated plate according to claim 6 , wherein a following formula is further satisfied:

y≦gx h ,

wherein, in the formula, g is a coefficient and h is an exponent with a base of x; if x is greater than or equal to 4×10 3 and less than 6×10 3 , g is 4.96×10 15 and h is −2.97; if x is greater than or equal to 6×10 3 and less than 3×10 4 , g is 1.80×10 6 and h is −1.00; if x is greater than or equal to 3×10 4 and less than 1×10 5 , g is 1.93×10 5 and h is −3.37×10 −1 ; and if x is greater than or equal to 1×10 5 and less than or equal to 1×10 6 , g is 3.99×10 3 and h is 0.

10 . The laminated plate according to claim 9 , wherein a following formula is further satisfied:

y≦ix j ,

wherein, in the formula, i is a coefficient and j is an exponent with a base of x; if x is greater than or equal to 2×10 3 and less than 3×10 3 , i is 6.34×10 14 and j is −2.97; if x is greater than or equal to 3×10 3 and less than 3×10 4 , i is 9.00×10 7 and j is −1.00; if x is greater than or equal to 3×10 4 and less than 1×10 5 , i is 2.05×10 6 and j is −6.33×10 −1 ; and if x is greater than or equal to 1×10 5 and less than or equal to 1×10 6 , i is 1.40×10 3 and j is 0.

11 . The laminated plate according to claim 6 , wherein a following formula is further satisfied:

y≦kx 1 ,

wherein, in the formula, k is a coefficient and 1 is an exponent with a base of x; if x is greater than or equal to 7×10 3 and less than 1×10 4 , k is 9.09×10 30 and 1 is −6.75; if x is greater than or equal to 1×10 4 and less than 1.2×10 4 , k is 7.08×10 12 and 1 is −2.22; if x is greater than or equal to 1.2×10 4 and less than 1×10 5 , k is 3.62×10 4 and 1 is −1.91×10 −1 ; and if x is greater than or equal to 1×10 5 and less than or equal to 1×10 6 , k is 4.02×10 3 and 1 is 0.

12 . The laminated plate according to claim 11 , wherein a following formula is further satisfied:

y≦mx n ,

wherein, in the formula, m is a coefficient and n is an exponent with a base of x; if x is greater than or equal to 6×10 3 and less than 9×10 3 , m is 2.74×10 27 and n is −5.94; if x is greater than or equal to 9×10 3 and less than 1.2×10 4 , m is 1.26×10 25 and n is −2.82; if x is greater than or equal to 1.2×10 4 and less than 1×10 5 , m is 8.62×10 4 and n is −3.27×10 −1 ; and if x is greater than or equal to 1×10 5 and less than or equal to 1×10 6 , m is 2.00×10 3 and n is 0.

13 . A method of producing a laminated plate comprising:

a bonding process of bonding a first plate and a second plate by an intermediate film,

wherein the first plate includes a first main surface arranged at a side opposite to the intermediate film, and a second main surface that contacts the intermediate film, the first plate having higher bending stiffness, compared to the second plate,

wherein the second plate is a glass plate having a third main surface that contacts the intermediate film, and a fourth main surface arranged at a side opposite to the intermediate film,

wherein, when, among cross sections including a normal line at a centroid of the first main surface, a cross section in which a radius of curvature of the first main surface becomes a maximum is a transverse section, and a cross section perpendicular to the transverse section is a longitudinal section, in a natural state prior to bonding, a radius of curvature of the second main surface is smaller than a radius of curvature of the third main surface both in a cross section corresponding to the transverse section and in a cross section corresponding to the longitudinal section, and

wherein a maximum value of bending compressive stress at an outer peripheral portion of the fourth main surface is less than or equal to 100 MPa.

14 . The method according to claim 13 , wherein, when a radius of curvature (mm) of the first main surface in the transverse section is x, and a radius of curvature of the first main surface in the longitudinal section is y, following formulas (1) through (3) are satisfied:

x≦ 1×10 6   (1),

y≦ 1×10 5   (2), and

y≧ax b   (3), and

wherein, in the formula (3), a is a coefficient; b is an exponent with a base of x; if x is greater than or equal to 2×10 2 and less than 5×10 2 , a is 6.06×10 10 and b is −2.51; if x is greater than or equal to 5×10 2 and less than 1×10 4 , a is 1.44×10 7 and b is −1.17; and if x is greater than or equal to 1×10 4 and less than 1×10 5 , a is 2.43×10 4 and b is −4.77×10 −1 .