JPH06287519A - Method for curing ultraviolet-curable adhesive - Google Patents

Abstract

PURPOSE:To rapidly cure an ultraviolet-curable adhesive at the joint of laser diode modules to thereby join the modules without the occurrence of deflection of optical axis due to thermal expansion, by a method wherein light that contains heat rays and is radiated from an ultraviolet light source is reflected by using a specified glass and the reflected light having heat rays removed therefrom is directed to the joint so that the joint is subjected to only ultraviolet rays. CONSTITUTION:To fix the joint 7 of laser diode modules 5 and 6 by using an ultraviolet-curing adhesive, light A containing heat rays and radiated from an ultraviolet light source 8 is reflected by using glass 9 coated with a multilayer dielectric film having a reflectance of at least 90% in a wavelength region from 250 to 40nm and that of at most 3% at other wavelengths, and the reflected light is directed to the joint.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of fixing a joint in a laser diode module used as a light source for optical measurement or optical communication.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional laser diode module is mainly composed of a laser diode 1, a first lens portion 2, a second lens portion 3 and an optical fiber portion 4, each of which has a holding portion. Are joined together. The light emitted from the laser diode 1 is collimated by the first lens 2 and then narrowed down to the optical fiber 4 by the second lens 3 as shown by the light traveling path B. The core diameter of the optical fiber used here is as small as several μm, and highly accurate optical axis adjustment is required. Each holding part is fixed with an adhesive, but compared to an organic adhesive with a long curing time of several hours,
Since an ultraviolet curable adhesive having a short curing time of tens of seconds is advantageous in terms of manufacturability, the ultraviolet curable adhesive has been used to fix the joint portion.

[0003]

As described above, the joint portion of the laser diode module is fixed by using the ultraviolet curable adhesive, but the light emitted from the ultraviolet light source contains heat rays in addition to ultraviolet rays. However, there is a problem in that the joint portion and the holding portion are also heated by the irradiation of the heat rays and thermal expansion occurs, and therefore the optical axis is deviated and the coupling efficiency is significantly deteriorated.

[0004]

In order to solve the above problems, a dielectric multilayer coating glass that reflects only ultraviolet rays is used to remove heat rays that cause thermal expansion from the light reflected from the ultraviolet light source. However, thermal expansion due to the temperature rise of the joint portion and the holding portion was prevented. This makes it possible to suppress the optical axis shift due to thermal expansion. That is, the present invention has a reflectance of 90% in a wavelength range of 250 nm to 400 nm for light including a heat ray emitted from an ultraviolet light source when fixing a bonding portion of a laser diode module using an ultraviolet curing adhesive. As described above, the method for curing an ultraviolet curable adhesive is characterized in that the dielectric multilayer coating glass having a reflectance of 3% or less at other wavelengths is used for reflection and the light is applied to the joint. is there.

[0005]

According to the present invention, by using the dielectric multi-layer coating glass that reflects only ultraviolet rays, the heat rays that cause thermal expansion are removed from the light emitted from the ultraviolet light source, and the bonding portion and the holding portion are protected. Thermal expansion due to temperature rise can be prevented. As a result, it is possible to quickly join the joints without causing the optical axis shift due to the expansion heat of the joints and the holding portion.

[0006]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of the present invention. In FIG. 1, the ultraviolet rays including the heat rays emitted from the ultraviolet light source 8 are reflected by the dielectric multilayer film coating glass 9 and strike the joint portion 7 as indicated by the light advancing path A. The dielectric multi-layer coating glass 9 has a concave surface so that ultraviolet rays can be collected. FIG. 2 is a view showing the structure of the dielectric multilayer film-coated glass, in which the concave surface of the glass 11 is coated with the dielectric multilayer film coat 10. FIG. 3 is a diagram showing the relationship between the reflectance and the wavelength of the dielectric multilayer coating. The laser diode module manufactured by the method according to the present invention had a change in coupling loss of 0.5 dB or less before and after bonding. According to the conventional method, the coupling loss is deteriorated by 3 dB or more, which is a great improvement.

[0007]

[Effects of the Invention] When fixing the joint portion of the laser diode module using the UV-curable adhesive, the dielectric multi-layer coating glass is used to reflect the light from the light source, which requires special expensive equipment. Since the heat rays can be removed very efficiently and only the ultraviolet rays can be applied to the joint portion, the deterioration of the coupling efficiency due to thermal expansion can be significantly reduced, and a laser diode module with low coupling loss can be manufactured.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of the present invention.

FIG. 2 is a view showing the structure of a dielectric multilayer film-coated glass.

FIG. 3 is a characteristic diagram showing a relationship between a wavelength and a reflectance of a dielectric multilayer film coat.

FIG. 4 is a diagram showing an optical coupling system of a laser diode module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 laser diode 2 1st lens 3 2nd lens 4 optical fiber 5 laser diode module holding | maintenance part 1 6 laser diode module holding | maintenance part 2 7 joining part (ultraviolet curing adhesive) 8 ultraviolet light source 9 dielectric multilayer coating glass 10 dielectric Multi-layer coating 11 Glass A Light traveling path B Light traveling path

Claims (1)

[Claims] 1. When the bonding portion of a laser diode module is fixed by using an ultraviolet curable adhesive, light including a heat ray emitted from an ultraviolet light source is emitted from 250 nm to 400 nm.
Characterized by reflecting the light using a dielectric multi-layer coating glass having a reflectance of 90% or more in the wavelength region of nm and a reflectance of 3% or less at other wavelengths, and irradiating the light to the joint portion. And a method for curing an ultraviolet-curing adhesive.