Light-conducting glass structures
AssigneeNippon Selfoc Co., Ltd.
InventorsIchiro Kitano, Ken Koizumi, Hiroyoshi Matsumura
Life of this patent
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Abstract
By heat treating a glass member containing at least one kind of cation to constitute a modifying oxide in contact with a source of another kind of cation to cause ion substitution, a light-conducting glass structure can be produced to have a refractive index distribution wherein the index varies progressively transversely to the intended light path, which is thereby bent toward the direction of increase of the index, such a light-conducting glass structure is not accompanied by differences or lagging of phase velocities of conducted light rays, spreading of the light flux width, and reflection losses.
Claims11
A glass structure for conducting light comprising:
- a glass body having a center axis and having an entrance surface and an exit surface both transverse to said center axis and a side surface surrounding said center axis;
- said glass body including therein SiO.sub.2, thallium oxide and an alkali metal oxide having relative concentrations such that the concentration of cations which constitute said SiO.sub.2 is substantially uniform in each planar cross-section perpendicular to said center axis the concentration in said cross-section of thallium ions which constitute said thallium oxide decreases continuously from said center axis toward said side surface, and the concentration in said cross-section of alkali metal ions which constitutes said alkali metal oxide increases continuously from said center axis toward said side surface;
- the variations in concentrations of said thallium ions and of said alkali metal ions effectively creating within the glass structure a refractive index gradient wherein, in said cross-section, the refractive index decreases continuously substantially in proportion to the square of the radial distance from said center axis, whereby light rays applied to said entrance surface are transmitted within the glass structure to said exit surface with repetition of refraction and without reflection and substantially without loss and without lagging phase velocities.
A glass structure for conducting light comprising:
- a glass body having a center axis and having an entrance surface and an exit surface both transverse to said center axis and a side surface surrounding said center axis, said glass body containing therein a glass forming oxide and at least first monovalent ions and second monovalent ions, said first monovalent ions and said second monovalent ions each constituting a glass modifying oxide and said first monovalent ions having a greater contribution to the increase of refractive index of the glass than said second monovalent ions;
- said glass body having a concentration gradient of said first monovalent ions and of said second monovalent ions such that the concentration of said first monovalent ions in a planar cross-section perpendicular to said center axis decreases continuously from said center axis towards said side surface of the glass structure and the concentration of said second monovalent ions in said cross-section increases continuously from said center axis toward said side surface and the relative concentrations of both kinds of monovalent ions being uniform along said center axis in each cross-section of said glass body;
- the variations in concentration of each kind of monovalent ions effectively creating within the glass structure a refractive index gradient wherein, in a planar cross-section perpendicular to said center axis, the refractive index decreases substantially in proportion to the square of the radial distance from said center axis, whereby light rays may be transmitted substantially without loss and without lagging phase velocities through the glass structure.
Dependencies are inferred from the claim text.