Method of making an index gradient light-conducting glass structure

Abstract

Abstract 1. A METHOD FOR PRODUCING AN ELONGATED LIGHT-CONDUCTING GLASS STRUCTURE HAVING A PREDETERMINED REFRACTIVE INDEX AND FOCUSING EFFECT AND COMPOSED OF AN ELONGATED GLASS BODY HAVING A CENTER AXIS AND ENTRANCE AND EXIT END SURFACES FRO LIGHT, BOTH TRANSVERSE TO SAID CENTER AXIS, AND A SIDE SURFACE ENCPMPASSING SAID CENTER AXIS, SAID GLASS BODY HAVING A REFRACTIVE INDEX GRADIENT WHEREIN SAID REFRACTIVE INDEX GRADIENT PRODUCED SAID FOCUSING EFFECT AND IS SUBSTANTIALLY EXPRESSED, AAT LEAST IN THE VICINITY OF SAID CENTER AXIS IN EACH PLANAR CORSS-SECTION PREPENDICULAR TO SAID CENTER AXIS, BY THE FOLLOWING EQUATION N=NO(1-A(Z)R2) WHEREIN NO REPRESENTS THE REFRACTIVE INDEX AT SAID CENTER AXIS, N REPRESENTS THE REFRACTIVE INDEX AT A DISTANCE R FROM SAID CENTER AXIS, AND A(Z) IS A POSITIVE CONSTANT AT THE PLANAR CROSS-SECTION, SAID POSITIVE CONSTANT AT THE THE VALUE THEREOF INCREASES GRADUALLY FROM AT LEAST ONE OF SAID ENTRANCE AND EXIT END SURFACES TOWARD AN INTERMEDIATE AXIAL PORTION OF THE GLASS BODY ALONG SAID CENTER AXIS WHICH COMPRISES: PROVIDING AN ELONGATED GLASS BODY COMPOSED OF A GLASS HAVING A UNIFROM HIGH REFRACTIVE INDEX CONTAINING FIRST IONS WHICH ARE UNIFROMLY DISTRIBUTED THROUGHOUT THE GLASS BODY AND ARE HIGHLY CONTRIBUTABLE TO THE REFRACTIVE INDEX OF THE GLASS BODY, SAID GLASS BODY HAVING A CIRCULAR CROSS-SECTION OF EQUAL RADIUS ALONG THE DIRECTION OF ITS LENGTH; CONTACTING SAID GLASS BODY AT ALL SIDE SURFACES WITH AN ION SOURCE CONTAINING SECOND IONS WHICH ARE LESS CONTRIBUTABLE TO THE REFRACTIVE INDEX OF SAID GLASS BODY THAN SAID FFIRST IONS AND WHICH ARE MUTUALLY ION-EXCHANGEABLE WITH SAID FIRST IONS IN SAID GLASS BODY; MAINTAINING SAID GLASS BODY IN CONTACT WITH SAID ION SOURCE AT AN ELEVATED TEMPERATURE AND FOR A TIME PERIOD SUFFICIENT TO EFFECT DIFFUSION OF SAID FIRST IONS FROM SAID GLASS BODY TO SAID ION SOURCE AND DIFFUSION OF SAID SECOND IONS FROM SAID ION SOURCE TO SAID GLASS BODY TO THEREBY ALTER THE UNIFORM DISTRIBUTION IN SAID GLASS BODY OF SAID FIRST IONS SUCH THAT THE REFRACTIVE INDEX DECREASES FROM THE ORIGINAL REFRACTIVE INDEX OF SAID GLASS BODY TO A GREATER EXTENT AT THE PORTION OF SAID GLASS BODY NEARER THE SURFACE OF THE GLASS BODY THAN AT THE CENTER WHEREBY SAID GLASS BODY HAS A REFRACTIVE INDEX GRADIENT SUBSTANTIALLY EXPRESSED, AT LEAST IN THE VICINITY OF SAID CENTER AXIS IN EACH PLANAR CROSS-SECTION PERPENDICULAT TO SAID CENTER AXIS, BY THE FOLLOWING EQUATION , N''-NO''(1-A''R2) WHEREIN NO'' REPRESENTED THE REFRACTIVE INDEX AT SAID CENTER AXIS, N'' REPRESENTS THE REFRACTIVE INDEX AT A DISTANCE R FROM SAID CENTER AXIS, AND A'' IS A POSITIVE CONSTANT A'' AND T PLANAR CROSS-SECTION, SAID POSITIVE CONSTANT A'' AND THE THE REFRACTIVE INDEX NO'' AT SAID CENTER AXIS BEING CONSTANT RESPECTIVELY ALONG THE CENTER AXIS OF SAID GLASS BODY; AND STRETCHING THE GLASS BODY IN THE DIRECTION OF THE CENTER AXIS OF SAID GLASS BODY WHILE HEATING SAME IN SUCH A MANNER THAT THE RATE OF STRETCHING IS LOWER IN THE VICINITY OF AT LEAST ONE OF SAID ENTRANCE AND EXIT END SURFACES THAN AT AN INTERMEDIATE AXIAL PORTION OF THE GLASS BODY ALONG SAID CENTER AXIS SO THAT THE REFRACTIVE INDEX AT BOTH THE CENTER AXIS AND THE SIDE SURFACE OF THE GLASS BODY AFTER STRETCHING MAINS SUBSTANTIALLY THE SAME AS THE REFRACTIVE INDEX AT BOTH TH STRETCHING; WHEREBY THE GLASS BODY AFTER STRETCHING HAS A CROSS-SECTIONAL RADIUS WHICH DECREASES GRADUALLY FROM AT LEAST ONE OF SAID ENTRANCE AND EXIT END SURFACES TOWARS THE INTERMEDIATE AXIAL PORTION OF THE GLASS BODY ALONG SAID CENTER AXIS AND SAID GLASS BODY HAS A REFRACTIVE INDEX GRADIENT AFTER STRETCHING AS SHWON BY THE AOFRESAID EQUATION (1) AND WHEREIN SAID AT LEAST ONE OF SAID ENTRANCE AND EXIT END SURFACES WHICH HAS THE LARGEST CROSS-SECTIONAL RADIUS OF THE GLASS BODY AFTER STRETCHING HAS THE MINIMUM VALUE OF A(Z)

Inventors

• 👤 H Matsumura
• 👤 S Ono

Bibliographic Details