JPH04264510A - Method for joining hold fittings and prism - Google Patents

Abstract

PURPOSE:To reduce the cost of the sealing operation and improve the yield by arranging the prism which has a columnar part coaxially in the cylindrical hold fittings and fusing a glass ring fitted in the annular gap between the both and performing the sealing operation. CONSTITUTION:The glass ring 20 and prism 30 made of optical glass are fitted coaxially in the edge opening 12 of the hold fittings 1 which is improved in wettability by a preheating-oxidizing treatment and they are mounted on the amount base 4 consisting of a mount base main body 31 and a carbon plate 42. Then a high-frequency heating device 5 which radiates a microwave for heating is used to perform the sealing operation in an atmosphere by raising and reducing the temperature. In this case, the high-frequency heating device 5 is only brought under heating control so that the heating ends in 5-10 minutes, so the sealing operation is easily carried out. In the sealing operation, the glass ring 20 is fused without being pressed to fill the gap between the hold fittings 1 and prism 3, so strict dimension control over the holt fittings 1, glass ring 20, and prism 3 is not necessary.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a joined body of a prism and a holding fitting used in a liquid mixture ratio sensor for optically detecting the mixture ratio of gasoline and alcohol in a mixed fuel.

0002

[Prior Art] Usually, a liquid mixture ratio sensor is constructed by fitting and fixing a prism to the end of a cylindrical holding metal fitting, and arranging a light emitting element and a light receiving element in the metal fitting facing each other with the prism in between. The end face (reflection surface) of the prism is exposed to a liquid to be measured which is a mixture of two or more different types of liquids, and the mixing ratio of the two liquids having different refractive indexes is optically detected. Conventionally, the holding fitting and the prism are joined together by fitting a glass ring 200 of an optical system and an optical glass 300 into an opening 110 of a metal holder 100 and placing it on a carbon base 400, as shown in FIG. However, it is carried out using an electric furnace. At this time, the sealing temperature of the electric furnace needs to be higher than the working temperature of the glass ring 200 and lower than the softening temperature of the optical glass 300. However, there is also a problem with the coefficient of thermal expansion, and glass ring materials that satisfy this type of condition are generally unavailable and expensive. Therefore, the glass ring 200 is pressed with a carbon jig 600 on which a weight 500 is placed,
This is done by heating the glass ring to a temperature above its softening temperature and below its working temperature.

0003

[Problems to be Solved by the Invention] However, in the conventional technology, the optical glass 300 may be deformed or the gas tightness of the bonded body may deteriorate due to sealing conditions such as dimensions, pressing force, and temperature of each member. Therefore, these must be strictly controlled, and there are disadvantages in that the sealing work is costly and the product does not hold well. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for joining a holding fitting and a prism, which can reduce the cost of sealing work and improve the fixation of the product.

0004

[Means for solving the problem] In order to solve the above problem,
In the present invention, an optical glass prism having a cylindrical part is arranged coaxially within a cylindrical holding fitting, a glass ring for sealing is fitted into the annular gap between the two, and the glass ring is melted by high-frequency heating. A structure is adopted in which the prism is sealed to the holding fitting.

[0005]

[Operation and Effects of the Invention] Since the holding metal fitting is heated by high frequency from the outside, the heat is transmitted to the holding metal fitting, the glass ring, and the prism in this order, and the glass ring becomes hotter selectively with respect to the prism, and only the glass ring comes first. The prism is melted and sealed to the holding fitting. Note that since the sealing is performed before the prism reaches its softening temperature, there is almost no deformation of the prism. Further, there is no need to strictly control the sealing conditions such as the dimensions, pressing force, temperature, etc. of the holding fittings, glass rings, and prisms, so the cost of the sealing work is low.

[0006]

[Embodiment] Next, an embodiment of the present invention will be explained based on FIGS. 1 to 3. As shown in FIG. 2, in the bonded body A, an optical glass 3 is bonded to an edge opening 12 of a metal holder 1 having an edge 11 via a sealing glass 2. As shown in FIG. 1, the metal holder 1 (approximately cylindrical), which is a holding fitting, is made of a material consisting of 50Ni-50Fe.
The inner diameter of the opening 12 is 10.2 mm, and the height of the edge 11 is 1 m.
m is set. The sealing glass 2 is SF glass (optical glass), and the size of the glass ring 20 (softening temperature 600° C.) before melting shown in FIG. 1 is an inner diameter of 8.2
mm, outer diameter 10 mm, and height 1.2 mm. The optical glass 3 (softening temperature: 720° C.), which is a prism, is made of BaF-based glass material and has a cylindrical shape with a diameter of 8 mm and a height of 8 mm.

[0007] The method for manufacturing the joined body A will be explained below. (1) In order to improve wettability, the metal holder 1 is subjected to preliminary oxidation treatment (in the atmosphere, at 400° C. for 1 hour). (2) Fit the glass ring 20 and the optical glass 3 coaxially into the edge opening 12 of the metal holder 1, and place them on the mounting table 4 consisting of the mounting table main body 41 and the carbon plate 42 placed on the main body 41. Place it on. (3) High-frequency heating device 5 that heats by radiating microwaves
The temperature was raised by applying current for 2.5 minutes (applied 3.5 kV in this case) to 5 minutes (applied 3 kV in this case), and then the temperature was lowered for the same time as the above-mentioned current application time (the power was gradually lowered).
The sealing work is performed in an atmospheric atmosphere.

The effects of this embodiment will be described below. (A) When we performed a He leak test on the sealed parts of the bonded body A, which was sealed within the above range, all (10 pieces of the same pattern were manufactured) showed 10-10 atm.
cc/sec or less, and the variation in leakage amount was extremely small.

(i) Joined body A sealed within the above range
Almost no thermal deformation was observed in optical glass 3. This is because the high frequency is applied from the outside of the metal holder 1, heat is transmitted in the order of the metal holder 1, the glass ring 20, and the optical glass 3, and the glass ring 20 melts before the optical glass 3 reaches its softening temperature. It is thought that there is (see Figure 3).

(c) The sealing work can be easily performed because the heating of the high-frequency heating device 5 can be controlled so that the heating is completed within 5 to 10 minutes. Further, during sealing, the glass ring 20 melts without being pressed and the gap between the metal holder 1 and the optical glass 3 is filled.
There is no need to strictly control the dimensions of the glass ring 20 and the optical glass 3. Therefore, the sealing cost can be significantly reduced.

The present invention includes the following embodiments in addition to the above embodiments. a. As shown in FIG. 4, carbon stands 43 and 44 are
Then, metal holder 1, glass ring 20, optical glass 3
The sealing may be carried out by high-frequency heating with support. b. A cylinder in the present invention includes an ellipse, an ellipse, an oval shape, etc. For example, the metal holder 1 and the glass ring 20 may have a cylindrical shape such as an ellipse in cross section, and the optical glass 3 may have a columnar shape such as an ellipse in cross section. good. Moreover, the edge lower surface 13, the glass ring lower surface 21, and the end surface 31 do not need to be joined flush.

Note that, as shown in FIG.
etc., it becomes a liquid mixture ratio sensor B, and this liquid mixture ratio sensor B includes an optical glass 3 in the mixed fuel 54.
The end face 31 of the sensor is exposed to detect the mixing ratio of gasoline and alcohol.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a sealing operation of a joined body according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the joined body.

FIG. 3 is a graph showing the temperature distribution during sealing of the bonded body.

FIG. 4 is an explanatory diagram of a joined body in another embodiment of the present invention.

FIG. 5 is a cross-sectional view of a liquid mixture ratio sensor manufactured using the assembled body.

FIG. 6 is an explanatory diagram illustrating a conventional technique.

[Explanation of symbols]

A zygote 1 Metal holder (holding metal fittings) 3 Optical glass (prism) 20 Glass ring

Claims (1)

[Claims] Claim 1: An optical glass prism having a cylindrical portion is arranged coaxially within a cylindrical holding fitting, a glass ring for sealing is fitted into the annular gap between the two, and the glass ring is heated by high frequency heating. A method for joining a holding fitting and a prism by melting and sealing the prism to the holding fitting.