公开(公告)号：JP2556569B2

公开(公告)日：1996-11-20

申请号：JP32982888

申请日：1988-12-27

Applicant: SUMITA OPTICAL GLASS

Inventor： TERAJIMA TOORU ,  SAWANOBORI SHIGETO ,  HASHIMOTO HITOSHI

IPC: G02B6/00 ,  C03B37/012 ,  C03B37/014

公开(公告)号：JPH0316933A

公开(公告)日：1991-01-24

申请号：JP15291389

申请日：1989-06-15

Applicant: SUMITA OPTICAL GLASS

Inventor： HASHIMOTO HITOSHI ,  SAWANOBORI SHIGETO ,  NAGAHAMA SHINOBU

IPC: G02B5/22 ,  C03C3/17 ,  C03C3/19 ,  C03C4/08 ,  F21V9/04

Abstract: PURPOSE:To obtain a glass for near infrared absorption filter, exhibiting water- resistance and weather-resistance durable to long-term use and having high absorption coefficient in near infrared region and high transmission in visible range by using a CuO-doped phosphate glass as a matrix. CONSTITUTION:The objective glass for near infrared absorption filter useful for the sensitivity correction of a light receiving element of a color image pickup device is a CuO-containing phosphate glass having a composition of (A) 65.0-75.0wt.% of P2O5, (B) 11.0-14.0wt.% of Al2O3, (C) 0-4.0wt.% of B2O3, (D) 3.0-9.0wt.% of K2O, (E) 2.0-6.0wt.% of MgO, (F) 0-4.0wt.% of ZnO and (G) 1.5-4.0wt.% of CuO.

公开(公告)号：JPH02175626A

公开(公告)日：1990-07-06

申请号：JP32982888

申请日：1988-12-27

Applicant: SUMITA OPTICAL GLASS

Inventor： TERAJIMA TORU ,  SAWANOBORI SHIGETO ,  HASHIMOTO HITOSHI

IPC: G02B6/00 ,  C03B37/012 ,  C03B37/014

Abstract: PURPOSE:To obtain the fiber preform having a uniform waveguide structure and drawable without causing the crystallization of the fiber surface layer by using a forming mold having a specific structure in place of a cylindrical mold for built-in casting process. CONSTITUTION:A columnar cylindrical mold 1 dividable into two in longitudinal direction and having a step having an inner diameter of the upper end larger than that of the core part is combined with a columnar bottom part 2 having the same diameter as the core part of the cylindrical mold, the cylindrical mold parts 1 are fixed together to prevent the separation and the bottom part 2 is made to be movable to obtain a forming mold to be used in the present process. A molten liquid 3 of clad glass is poured into the mold through the upper end, the bottom part 2 is removed after solidifying the part of the molten glass contacting with the mold and the molten glass in the core part of the mold maintained in fluid state is discharged to obtain a glass tube. The step part of the top end of the cylindrical mold prevents the top end of the glass tube from slipping off by its own weight and keeps the inner diameter of the glass tube at a definite level. The mold concentration is maintained within the range from a level near the glass transition temperature to the glass deformation temperature. A molten glass liquid 4 for core is poured into the obtained glass tube.