JPS61228939A - Manufacture of rod lens - Google Patents

Abstract

PURPOSE:To provide the manufacture of a rod lens, the end face of which is worked out in a hemispherical shape without using grinding tool and at the same time the time to work out said end face in the hemispherical is shorten, by a method wherein photo-setting resin is adhered to the end face of the rod lens and, after that, set by being exposed to light. CONSTITUTION:When a certain amount of photo-setting resin 9 is dropped on the end face of a rod lens 3 from a needle 8 and exposed to light with a lamp 10, the photo-setting resin 9, which takes the hemispherical shape due to the surface tension of the resin, is set and the rounded end face of the rod lens 3 results. In addition, the curvature of the surface of the photo-setting resin 9 is determined by the dripped amount. Further, the end face of the rod lens can also be made in a hemispherical shape by using transparent thermosetting resin. In this case, the process time becomes longer by the time required for thermosetting. However, the time is strikingly shortened when the rod lens is mass-produced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a rod lens that can be used in an optical transmitter, optical receiver, or optical coupler.

(Constitution of Conventional Example and Problems thereof) In recent years, optical communication systems using optical fibers, light-emitting and light-receiving elements have reached a practical stage, and technical development is being actively carried out.

Traditionally, optical communication systems consist of a transmitting circuit, a light emitting element, a condensing rod lens, an optical fiber, a light receiving element, and a receiving circuit. Semiconductor lasers are used as such.

Hereinafter, a long-distance optical communication system using the conventional semiconductor laser as described above will be described with reference to the drawings.

Fig. 2 shows the configuration of a conventional optical communication system using a semiconductor laser, in which 1 is a transmission circuit that modulates an input electrical signal into a transmission signal, 2 is a semiconductor laser that converts the transmission signal into an optical signal, 3 is a condensing rod lens that efficiently inputs the optical signal emitted from the semiconductor laser 2 into the optical fiber 4; 5 is a light receiving element that receives the optical signal input from the optical fiber 4 and converts it into a received signal; 6 is a light receiving circuit that detects and amplifies the received signal and outputs an electric signal.

In the conventional example configured in this manner, a transmission signal output from the transmission circuit 1 is converted into an optical signal by the semiconductor laser 2, and then this optical signal is made to enter the optical fiber 4 through the rod lens 3. and.

An optical signal that propagates through the optical fiber 4 and enters the light receiving element 5 is converted into a received signal, and the received signal is detected and amplified to produce an electrical signal that is output from the light receiving circuit 6.

However, there was a problem in that the characteristics of the semiconductor laser 2 deteriorated due to part of the laser light reflected by the end face of the rod lens 3 (hereinafter referred to as return light).

FIG. 3 shows the configuration of another conventional optical communication system using a semiconductor laser, in which 7 is a rod lens whose end face is cut into a hemispherical shape.

In the conventional example configured in this way, since the end surface of the rod lens 7 is semispherical, the returned light is scattered.

Deterioration of the characteristics of the semiconductor laser 2 is suppressed.

However, since the end face of the rod lens 7 has to be ground into a hemispherical shape, there are problems in that it takes time to manufacture the rod lens 7 and it takes time and effort to maintain the grinding tool.

In view of the above-mentioned problems, the present invention provides a rod lens manufacturing method that processes the end face into a hemispherical shape without using a grinding tool and reduces the time required to process the end face of the rod lens into a hemispherical shape. The purpose is to

(Means and effects for solving the problems) In the present invention, a photocurable resin is adhered in a hemispherical shape to the end face of a translucent cylindrical rod lens.

The end face of a rod lens is processed into a hemispherical shape by exposure and curing.

(Example) Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 shows a method for manufacturing a rod lens according to the present invention. The same reference numerals as those in FIG. A needle 10 is a lamp for curing the photocurable resin 9 dropped onto the end surface of the rod lens 3.

In this embodiment configured in this way, if a certain amount of photocurable resin 9 is dropped from the needle 8 onto the end surface of the rod lens 3 and exposed to light using the lamp 10, the photocurable resin becomes hemispherical due to surface tension. The hardening tree JJ19 hardens and the end surface of the rod lens 3 becomes rounded.

Note that the degree of curvature of the surface of the photocurable resin 9 is determined by the amount of the resin dropped.

Further, in the description of the embodiment, a photocurable resin is used, but the end face of the rod lens can be made hemispherical even if a translucent thermosetting resin is used. However, in that case, the process time will be longer by the time required for heat curing, but in the case of mass production, the time will be significantly shortened.

(Effects of the Invention) As explained above, according to the present invention, a light-transmitting photocurable resin or a heat-transmitting resin is attached to both ends or one end of a cylindrical light-transmitting lens whose refractive index decreases with distance from the central axis. By dropping the curable resin in a hemispherical shape and curing it, the time (manufacturing time) for processing the end face of the rod lens into a hemispherical shape is shortened.

This has the effect of eliminating the need to maintain tools as in the past.

[Brief explanation of the drawing]

11th! 1 is a diagram showing the manufacturing method of the rod lens of the present invention, FIG. 2 is a configuration diagram of a conventional optical communication system using a semiconductor laser, and FIG. 3 is a conventional optical communication system using a rod lens with a spherical end surface. FIG. 3...Rod lens, 9...Photocurable resin.

Claims (1)

[Claims] Manufacture of a rod lens characterized in that the end face of a cylindrical rod lens having transmissive properties is rounded by curing a light-transmitting photo-curing resin or thermosetting resin attached in a hemispherical manner to the end face of the rod lens. Method.