Silica glass member for hermetic sealing of ultraviolet SMD LED element and method for manufacturing quartz glass member for ultraviolet LED

Abstract

Provided is a silica glass member for hermetic sealing of an ultraviolet SMD LED element to be suitably used for hermetic sealing of, and as a transmission window material for, a surface mount-type package (SMD) having an ultraviolet LED mounted thereon and configured to emit ultraviolet light in a wavelength range of from 200 nm to 350 nm. The silica glass member for hermetic sealing includes a silica glass substrate, which is homogeneously and integrally formed without an internal boundary, wherein the silica glass substrate has: a first surface on an inside opposed to an SMD LED element; and a second surface on an outside corresponding to the first surface, wherein an outer peripheral portion of the first surface has formed therein a substrate joining plain surface for joining to the container outer periphery joining plain surface, and wherein the second surface on the outside corresponding to the first surface has formed therein a lens-like convex portion configured to process emitted light from the ultraviolet SMD LED element.

Description

TECHNICAL FIELD[0001]The present invention firstly relates to a silica glass member to be used for hermetic sealing of an ultraviolet LED configured to emit ultraviolet light in a wavelength range of from 200 nm to 350 nm, and more specifically, to a silica glass member to be suitably used for hermetic sealing of, and as a transmission window material for, a surface mount-type package (commonly called a surface mount device (SMD)) having an ultraviolet LED mounted thereon and configured to emit ultraviolet light in a wavelength range of from 200 nm to 350 nm. The present invention secondly relates to a method of manufacturing a quartz glass member for an ultraviolet LED at a wavelength of from 200 nm to 400 nm.BACKGROUND ART[0002]An ultraviolet LED configured to emit light in a deep ultraviolet wavelength band is expected to be applied in a wide range of fields, such as virus sterilization, drinking water, air purification, resin curing, decomposition of environmental pollutants, a ...

AI Technical Summary

Benefits of technology

The present invention provides a silica glass member for sealing an ultraviolet LED and a method for manufacturing it. This glass member has excellent light transmission in the ultraviolet range and is suitable for use in surface mount-type packages. Additionally, the invention provides a method for repairing a defect in the glass to improve its light absorption and prevent defect-related absorption.

Problems solved by technology

However, a range of use of the gas light source is limited because of its short lifetime, its emission wavelength, which is limited only to an emission line of a gas, a substance contained therein that is harmful to a human body / environment, such as mercury, and an extremely large size and power consumption of the light source.

The ultraviolet LED emits light having a wavelength of from 200 nm to 400 nm, and has a problem in that a lens made of a silicone resin, which has hitherto been used for a visible light LED, undergoes deterioration of the resin or does not transmit the light.

In addition, there is also a problem in that light extraction efficiency from an ultraviolet LED element is extremely low.

However, there are problems in that, with a window plate made of quartz glass, light is diffused, and hence a desired light intensity is not obtained, and a hemispherical lens is difficult to mount on a package.

This method can provide a transparent quartz glass body by degreasing and purifying a molded body, followed by firing, but has a problem in that purification treatment with chlorine or hydrogen chloride generates an optical absorption band at a wavelength of about 250 nm (5.0 eV) due to an oxygen-deficient defect (Non Patent Document 1).

However, the method is limited in its effect to a quartz glass surface and requires treatment at high temperature.

It is said that there are significant technical obstacles between UVA and UVB or UVC.

However, for ultraviolet light of UVB or UVC, such organic material is insufficient in terms of light transmission property, and is also insufficient in terms of durability against UV light.

In addition, a borosilicate-based glass material having a satisfactory UV transmission property, which is often used for UVA, LED, also cannot be used due to problems with the light transmission property (even borosilicate glass hardly transmits ultraviolet light having a wavelength of 350 nm or less) and the durability.

However, the silica glass needs polishing in order to constitute a smooth surface having a high light transmission property suitable as the window material or the lens material, and hence cannot integrally constitute a smooth surface in a member in which a plain surface and a spherical surface coexist.

However, from the viewpoint of serving as a member for a UVB-LED or a UVC-LED, there is hardly any adhesive having a sufficient transmission property and sufficient durability in such wavelength region.

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