Reinforced plate glass and method for manufacturing the same

Abstract

[Object] To provide a method of manufacturing a reinforced plate glass by which glass surface strength can be sufficiently increased, and a stable quality reinforced plate glass is manufactured at high production efficiency, and to provide a reinforced plate glass manufactured by the manufacturing method. [Solving Means] A reinforced plate glass ( 10 ) is formed of an inorganic oxide glass, and is provided with a compression stress layer by chemical reinforcement on plate surfaces ( 11, 12 ) opposed to each other in a plate thickness direction. Plate end faces ( 13, 14, 15, 16 ) have regions where a compression stress is formed and regions where no compression stress is formed.

1 . A reinforced plate glass made of an inorganic oxide glass, comprising a compression stress layer formed by chemical reinforcement on each of plate surfaces opposed to each other in a plate thickness direction, and a region where a compression stress is formed and a region where a compression stress is not formed on a plate end face. 
   
   
       2 . The reinforced plate glass according to  claim 1 , wherein the region where a compression stress is formed is distributed in parallel with the plate surface on the plate end face. 
   
   
       3 . The reinforced plate glass according to  claim 1 , wherein a stress distribution of the compression stress layer in a plate thickness direction is limited in accordance with a compression stress function represented by a compression stress value of the plate surface, a thickness size of the compression stress layer, and a thickness size of the region where a compression stress is not formed. 
   
   
       4 . The reinforced plate glass according to  claim 1 , wherein the compression stress function is a function obtained by dividing a product of the compression stress value and the thickness size of the compression stress layer by the thickness size of the region where a compression stress is not formed, and a value calculated by the function is 40 MPa or less. 
   
   
       5 . The reinforced plate glass according to  claim 1 , wherein a compression stress value of at least one of the plate surfaces is in a range of from 200 to 1,500 MPa. 
   
   
       6 . The reinforced plate glass according to  claim 1 , wherein an average breaking stress by a four-point bending test according to JIS R1601 (1995) is 400 MPa or more, and a Weibull coefficient according to JIS R1625 (1996) is 3 or more. 
   
   
       7 . The reinforced plate glass according to  claim 1 , comprising 50 to 80% of SiO 2 , 0 to 15% of B 2 O 3 , 3 to 25% of Al 2 O 3 , 0 to 20% of Li 2 O, 0 to 20% of Na 2 O, 3 to 25% of Li 2 O+Na 2 O, 0 to 20% of K 2 O, 0 to 10% of CaO+MgO+ZnO+SrO+BaO, and 0 to 10% of TiO 2 +ZrO 2 , represented by percent by mass of an oxide conversion. 
   
   
       8 . The reinforced plate glass according to  claim 1 , wherein the plate end face is a surface formed by physical processing. 
   
   
       9 . The reinforced plate glass according to  claim 1 , wherein the physical processing is any one of laser cutting and scribe cleaving. 
   
   
       10 . A method of manufacturing a reinforced plate glass, comprising a compression reinforcement step of forming a compression stress layer on a surface of a plate glass by chemical reinforcement and a dividing step of applying a tensile stress to a plate surface of the plate glass chemically reinforced by the compression reinforcement step and dividing the plate glass, to thereby obtain the reinforced glass according to  claim 1 . 
   
   
       11 . The method of manufacturing a reinforced plate glass according to  claim 10 , wherein a stress distribution in a plate thickness direction of a compression stress layer of the plate surface is limited in accordance with a compression stress function represented by a compression stress value of the plate surface, a thickness size of the compression stress layer, and a thickness size of a region where a compressive force is not formed, due to the compression reinforcement step. 
   
   
       12 . The method of manufacturing a reinforced plate glass according to  claim 11 , wherein the dividing step is conducted by any one of laser cutting and scribing cleaving. 
   
   
       13 . The method of manufacturing a reinforced plate glass according to  claim 12 , wherein the scribing cleaving is conducted under a force applying condition of from 0.5 to 1.5 kgf with respect to the plate surface. 
   
   
       14 . The method of manufacturing a reinforced plate glass according to  claim 12 , wherein the scribing cleaving is conducted at a scribing speed of from 10 to 1,000 mm/s. 
   
   
       15 . The method of manufacturing a reinforced plate glass according to  claim 12 , wherein the laser cutting is conducted by laser light radiated by a carbon dioxide laser light source with an output of from 10 to 100 W. 
   
   
       16 . The method of manufacturing a reinforced plate glass according to  claim 11 , wherein the laser cutting is conducted by operating radiation light at a transfer speed of from 5 to 100 mm/s with respect to a plate glass surface. 
   
   
       17 . The reinforced plate glass according to  claim 2 , wherein a stress distribution of the compression stress layer in a plate thickness direction is limited in accordance with a compression stress function represented by a compression stress value of the plate surface, a thickness size of the compression stress layer, and a thickness size of the region where a compression stress is not formed. 
   
   
       18 . The reinforced plate glass according to  claim 3 , wherein the compression stress function is a function obtained by dividing a product of the compression stress value and the thickness size of the compression stress layer by the thickness size of the region where a compression stress is not formed, and a value calculated by the function is 40 MPa or less. 
   
   
       19 . The reinforced plate glass according to  claim 17 , wherein the compression stress function is a function obtained by dividing a product of the compression stress value and the thickness size of the compression stress layer by the thickness size of the region where a compression stress is not formed, and a value calculated by the function is 40 MPa or less. 
   
   
       20 . The reinforced plate glass according to  claim 2 , wherein a compression stress value of at least one of the plate surfaces is in a range of from 200 to 1,500 MPa.