Preforms for precision press molding, optical elements, and methods of manufacturing the same

Abstract

Preforms for precision press molding made of optical glass, optical elements, and methods of manufacturing the same are provided. The preforms are suited to precision press molding having a broad range of dispersion characteristics, a low glass transition temperature, a low sag point, and good resistance to devitrification while containing no PbO. The optical element is obtained by precision press molding the preform. One example of the preform has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32. The other example of the preform has an Abbé number (νd) exceeding 32.

1 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : 6 to 30 molar percent (excluding 6 molar percent and exceeding 4 weight percent),   B 2 O 3 : 0 to 30 molar percent,   WO 3 : 1 to 20 molar percent,   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   ZnO: 0 to 10 weight percent (excluding 10 weight percent),   which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         2 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : 6 to 30 molar percent (excluding 6 molar percent),   B 2 O 3 : 0 to 30 molar percent (excluding 0 molar percent),   WO 3 : 1 to 20 molar percent,   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   ZnO: 0 to 10 weight percent (excluding 10 weight percent),   which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         3 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : 6 to 30 molar percent (excluding 6 molar percent),   B 2 O 3 : 0 to 30 molar percent,   WO 3 : 1 to 15 molar percent (less than 15 weight percent),   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   ZnO: 0 to 10 weight percent (excluding 10 weight percent), which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         4 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : 6 to 30 molar percent (excluding 6 molar percent and exceeding 4 weight percent),   B 2 O 3 : 0 to 30 molar percent,   WO 3 : 1 to 20 molar percent,   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   where the Li 2 O, Na 2 O, and K 2 O content is 0 to 15 percent (excluding 15 weight percent), which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         5 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : 6 to 30 molar percent (excluding 6 molar percent),   B 2 O 3 : 0 to 30 molar percent (excluding 0 molar percent),   WO 3 : 1 to 20 molar percent,   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent), where the Li 2 O, Na 2 O, and K 2 O content is 0 to 15 percent (excluding 15 weight percent), which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         6 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : 6 to 30 molar percent (excluding 6 molar percent),   B 2 O 3 : 0 to 30 molar percent,   WO 3 : 0 to 15 molar percent (less than 15 weight percent),   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   where the Li 2 O, Na 2 O, and K 2 O content is 0 to 15 percent (excluding 15 weight percent), which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         7 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : 0 to 30 molar percent (excluding 0 molar percent and exceeding 4 weight percent),   B 2 O 3 : 0 to 30 molar percent,   WO 3 : 1 to 20 molar percent,   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   ZnO: 0 to 10 weight percent (excluding 10 weight percent),   where the weight ratio of (TiO 2  content/Bi 2 O 3  content) is less than 0.5, which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         8 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : 0 to 30 molar percent (excluding 0 molar percent),   B 2 O 3 : 0 to 30 molar percent (excluding 0 molar percent),   WO 3 : 1 to 20 molar percent,   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   ZnO: 0 to 10 weight percent (excluding 10 weight percent),   where the weight ratio of (TiO 2  content/Bi 2 O 3  content) is less than 0.5, which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         9 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : 0 to 30 molar percent (excluding 0 molar percent),   B 2 O 3 : 0 to 30 molar percent,   WO 3 : 0 to 15 molar percent (less than 15 molar percent),   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   ZnO: 0 to 10 weight percent (excluding 10 weight percent),   where the weight ratio of (TiO 2  content/Bi 2 O 3  content) is less than 0.5, which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         10 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : greater than 4 weight percent and less than or equal to 30 molar percent,   B 2 O 3 : 0 to 30 molar percent,   WO 3 : 1 to 20 molar percent,   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   where the Li 2 O, Na 2 O, and K 2 O content is 0 to 15 percent (excluding 15 weight percent) and the weight ratio of (TiO 2  content/BiO 2  content) is less than 0.5, which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         11 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : 0 to 30 molar percent (excluding 0 molar percent),   B 2 O 3 : 0 to 30 molar percent (excluding 0 molar percent),   WO 3 : 1 to 20 molar percent,   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   where the Li 2 O, Na 2 O, and K 2 O content is 0 to 15 percent (excluding 15 weight percent) and the weight ratio of (TiO 2  content/BiO 2  content) is less than 0.5, which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         12 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Nb 2 O 5 : 1 to 30 molar percent   TiO 2 : 0 to 20 molar percent (excluding 0 molar percent),   Bi 2 O 3 : 0 to 30 molar percent (excluding 0 molar percent),   B 2 O 3 : 0 to 30 molar percent,   WO 3 : 0 to 15 molar percent (excluding 15 weight percent),   BaO: 0 to 15 molar percent,   Li 2 O: 3 to 15 weight percent (excluding 3 weight percent),   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   where the Li 2 O, Na 2 O, and K 2 O content is 0 to 15 percent (excluding 15 weight percent) and the weight ratio of (TiO 2  content/Bi 2 O 3  content) is less than 0.5, which has a refractive index (nd) of greater than or equal to 1.7 and an Abbé number (νd) of less than or equal to 32.   
     
     
         13 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Bi 2 O 3 : 0.1 to 7 molar percent (excluding 7 molar percent),   Na 2 O: 0 to 30 molar percent,   K 2 O: 0 to 30 molar percent,   where the combined content of Li 2 O, Na 2 O, and K 2 O is less than 40 molar percent,   ZnO: 0 to 35 molar percent,   CaO: 0 to 35 molar percent,   BaO: 0 to 50 molar percent,   Nb 2 O 5 : 0 to 35 molar percent   WO 3 : 0 to 25 molar percent,   where the combined content of Nb 2 O 5  and WO 3  exceeds 0 molar percent,   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   where 0 to 1 weight percent of Sb 2 O 3  is added to the total content of glass components, which has an Abbé number (νd) exceeding 32.   
     
     
         14 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Bi 2 O 3 : 0.1 to 7 molar percent (excluding 7 molar percent),   Lip: 10 to 40 molar percent (excluding 10 molar percent and 40 molar percent),   Na 2 O: 0 to 30 molar percent,   K 2 O: 0 to 30 molar percent,   where the combined content of Li 2 O, Na 2 O, and K 2 O is less than 40 molar percent,   ZnO: 0 to 35 molar percent,   CaO: 0 to 35 molar percent,   BaO: 0 to 50 molar percent,   Nb 2 O 5 : 0 to 35 molar percent   WO 3 : 0 to 25 molar percent,   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   where 0 to 1 weight percent of Sb 2 O 3  is added to the total content of glass components, which has an Abbé number (νd) exceeding 32.   
     
     
         15 . A preform for precision press molding, characterized by being comprised of an optical glass the components of which are:
 P 2 O 5 : 15 to 70 molar percent,   Bi 2 O 3 : 0.1 to 7 molar percent (excluding 7 molar percent),   Na 2 O: 0 to 30 molar percent,   K 2 O: 0 to 30 molar percent,   where the combined content of Li 2 O, Na 2 O, and K 2 O is less than 40 molar percent,   ZnO: 0 to 35 molar percent,   CaO: 0 to 35 molar percent,   BaO: 20 to 50 molar percent (excluding 20 molar percent),   Nb 2 O 5 : 0 to 35 molar percent   WO 3 : 0 to 25 molar percent,   SiO 2 : 0 to 5 weight percent (excluding 5 weight percent),   where 0 to 1 weight percent of Sb 2 O 3  is added to the total content of glass components, which has an Abbé number (νd) exceeding 32.   
     
     
         16 . A preform for precision press molding, characterized by being comprised of an optical glass comprising essential components in the form of 15 to 70 molar percent of P 2 O 5 , more than 4 weight percent and less than or equal to 30 molar percent of Bi 2 O 3 , a quantity of TiO 2  of less than 0.5 times the content by weight of Bi 2 O 3 , and 0 to 5 weight percent (excluding 5 weight percent) of SiO 2 , and having an Abbé number (νd) of less than or equal to 32; and by being formed by solidifying glass the entire surface of which is in a molten state. 
     
     
         17 . A preform for precision press molding, characterized by being comprised of an optical glass comprising essential components in the form of 15 to 70 molar percent of P 2 O 5 , Bi 2 O 3 , and B 2 O 3 , a quantity of TiO 2  of less than 0.5 times the content by weight of Bi 2 O 3 , and 0 to 5 weight percent (excluding 5 weight percent) of SiO 2 , and having an Abbé number (νd) of less than or equal to 32; and by being formed by solidifying glass the entire surface of which is in a molten state. 
     
     
         18 . A preform for precision press molding, characterized by being comprised of an optical glass comprising essential components in the form of 15 to 70 molar percent of P 2 O 5  and Bi 2 O 3 , optional components in the form of 0 to 15 weight percent (excluding 15 weight percent) of WO 3 , a quantity of TiO 2  of less than 0.5 times the content by weight of Bi 2 O 3 , and 0 to 5 weight percent (excluding 5 weight percent) of SiO 2 , and having an Abbé number (νd) of less than or equal to 32; and by being formed by solidifying glass the entire surface of which is in a molten state. 
     
     
         19 . A preform for precision press molding, characterized by being comprised of an optical glass comprising essential components in the form of 15 to 70 molar percent of P 2 O 5  and Bi 2 O 3 , a quantity of TiO 2  of less than 0.5 times the content by weight of Bi 2 O 3 , and 0 to 5 weight percent (excluding 5 weight percent) of SiO 2 , and having an Abbé number (νd) of less than or equal to 32; and by being formed by solidifying glass the entire surface of which is in a molten state. 
     
     
         20 . A preform for precision press molding, characterized by being comprised of an optical glass comprising essential components in the form of 15 to 70 molar percent of P 2 O 5 , more than 4 weight percent and less than or equal to 30 molar percent of Bi 2 O 3 , a quantity of TiO 2  of less than 0.5 times the content by weight of Bi 2 O 3 , and 0 to 5 weight percent (excluding 5 weight percent) of SiO 2 ; and by being formed by solidifying glass the entire surface of which is in a molten state. 
     
     
         21 . A preform for precision press molding, characterized by being comprised of an optical glass comprising essential components in the form of 15 to 70 molar percent of P 2 O 5 , Bi 2 O 3 , and Bi 2 O 3 , a quantity of TiO 2  of less than 0.5 times the content by weight of Bi 2 O 3 , and 0 to 5 weight percent (excluding 5 weight percent) of SiO 2 ; and in that the entire surface thereof is a free surface. 
     
     
         22 . A preform for precision press molding, characterized by being comprised of an optical glass comprising essential components in the form of 15 to 70 molar percent of P 2 O 5  and Bi 2 O 3 , optional components in the form of 0 to 15 weight percent (excluding 15 weight percent) of WO 3 , a quantity of TiO 2  of less than 0.5 times the content by weight of Bi 2 O 3 , and 0 to 5 weight percent (excluding 5 weight percent) of SiO 2 ; and in that the entire surface thereof is a free surface. 
     
     
         23 . A preform for precision press molding, characterized by being comprised of an optical glass comprising essential components in the form of 15 to 70 molar percent of P 2 O 5  and Bi 2 O 3 , a quantity of TiO 2  of less than 0.5 times the content by weight of Bi 2 O 3 , and 0 to 5 weight percent (excluding 5 weight percent) of SiO 2 , and having an Abbé number (νd) of less than or equal to 32; and in that the entire surface thereof is a free surface. 
     
     
         24 . A method of manufacturing a preform for precision press molding, characterized in that a glass melt gob of prescribed weight is separated from a glass melt flowing out of a flow pipe and up to solidification of the glass melt gob, a preform according to any of  claim 1  to  23  with a weight equal to the above prescribed weight is formed. 
     
     
         25 . An optical element obtained by precision press molding the preform according to any of  claim 1  to  23  above or a preform manufactured by the manufacturing method according to  claim 24 . 
     
     
         26 . A method of manufacturing an optical element characterized in that in a method of manufacturing an optical element by heating a glass preform and conducting precision press molding, the preform according to any of  claim 1  to  23  or a preform manufactured by the manufacturing method according to  claim 24  above is heated and precision press molded with a pressing mold. 
     
     
         27 . The method of manufacturing an optical element according to  claim 26  wherein the preform and pressing mold are both heated and precision press molding is conducted. 
     
     
         28 . The method of manufacturing an optical article according to  claim 26 , wherein a heated preform is introduced into a pressing mold that has been preheated separately from said preform and precision press molding is conducted.