JPH07221349A - Airtight glass lens cap - Google Patents

Abstract

PURPOSE:To improve the shape and dimensional accuracy of a lens by welding a ring-like member to the circumference of a lens forming section on the internal surface of a cap main body while the member is brought into contact with light-transmitting glass. CONSTITUTION:After placing a glass tablet T composed of hard glass plate, etc., on one end side of a cap main body 10, the tablet T is melted by heating the tablet T from the one end of the main body 10. As a result, a free curved surface is formed on one side of the tablet T due to the viscosity of the glass. Then the main body 10 is turned upside down and, at the same time, a ring-like member 12 is dropped into the main body 10. When the tablet T is again melted by heating in this state, another free curved surface is formed on the other side Tb of the tablet T due to the viscosity of the glass and, as a result, a lens 11 is formed by utilizing the viscosity of the glass. Therefore, the surface of the lens 11 in the main body 10 can be stably formed with high dimensional accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic glass lens cap for an optical semiconductor device such as a light emitting element or a light receiving element. Airtight glass lens caps for optical semiconductor devices include
For collecting incoming and outgoing light or converting it to parallel light,
Although there is one provided with a spherical lens made of light-transmitting glass, such a spherical lens is generally expensive, which causes an increase in the cost of the entire cap.

[0002]

Therefore, an airtight glass lens cap as shown in FIG. 4 is known. This airtight glass lens cap utilizes the viscosity of glass to obtain an inexpensive lens. A circular through hole 1a is formed in the cap body 1, and a lens made of light transmitting glass is formed in this through hole 1a. Two
It has a fused structure.

FIG. 5 is a process diagram of fusing the lens 2. First, as shown in FIG. 5 (a), a tablet T (hereinafter referred to as “glass tablet”) such as a glass plate, a glass block, or a glass powder molded body is placed on one end side of the cap body 1 and then, as shown in FIG. As shown in b), when the glass tablet T is melted by heating from one end side of the cap body 1, a free curved surface due to the viscosity of the glass is formed on one surface Ta of the glass tablet T.

Next, as shown in FIG. 5 (c), the cap body 1 is turned upside down and heated again to melt the glass tablet T, and the other surface Tb of the glass tablet T is then melted.
Similarly, a free curved surface due to the viscosity of glass is formed, and a convex lens 2 utilizing the viscosity of glass is formed.

[0005]

However, in such a conventional hermetic glass lens cap, since the lens 2 is formed only by the viscosity of the glass, the side facing the inside of the cap body 1 ( There is a problem that the shape and dimensional accuracy of the lens (see Tb in FIG. 5) cannot be stably obtained.

That is, as shown in FIG. 6 which is a partially enlarged view of FIG.
Climb easily along the inner wall surface of the glass, the molten state of the glass becomes unstable, the height between the lens curved surfaces decreases, the shape of the lens becomes uneven, and the dimensional accuracy also decreases It has a drawback that optical characteristics cannot be obtained. [Purpose] Therefore, an object of the present invention is to improve the accuracy of the shape and size of a lens by a simple device.

[0007]

In order to achieve the above object, the present invention provides a lens formed by fusing light transmitting glass to a circular through hole formed in a cap body in a hermetically sealed manner. In a hermetically sealed glass lens cap,
Around the lens forming portion on the inner surface of the cap body, a ring-shaped member is brought into contact with the light-transmissive glass and fused, or the inner diameter of the ring-shaped member is substantially equal to the inner diameter of the through hole. Equal to or greater than, and
The outer diameter of the ring-shaped member is slightly smaller than the inner diameter of the cylindrical portion of the cap body.

[0008]

In the present invention, the light-transmitting glass melted by the ring-shaped member is dammed. Therefore, the molten light-transmitting glass is prevented from climbing up to the inner wall surface of the cap body, the height of the lens surface is not reduced, and the accuracy of the shape and size of the lens is improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are views showing an embodiment of an airtight glass lens cap according to the present invention. In FIG. 1, reference numeral 10 denotes a cylindrical cap body having an outwardly-extending rib 10a formed at its lower end, and a circular through hole 10b is formed in a wall surface on one end side of the cap body 10. The cap body 10 is formed of an iron-nickel-cobalt alloy such as Kovar or an iron-nickel alloy such as 42 alloy.

A lens 11 formed by fusing light-transmitting glass is adhered to the through hole 10b while maintaining airtightness. The light-transmitting glass is made of hard glass such as borosilicate glass. Can be used. The cap body 10
In the case where is formed of a material having a relatively large coefficient of thermal expansion, the composition of borosilicate glass or the like may be changed, or soft glass such as soda barium glass may be used.

Reference numeral 12 denotes a ring-shaped member housed inside the cap body 10. The inner diameter of the ring-shaped member 12 is equal to or larger than the inner diameter of the through hole 10b, and when the glass tablet is fused by the ring-shaped member 12. I try to control the flow of. The outer diameter of the ring-shaped member 12 is preferably slightly smaller than the inner diameter of the cylindrical portion of the cap body 10. Further, an iron-nickel-cobalt alloy such as Kovar or an iron-nickel alloy such as 42 alloy is used for the ring-shaped member 12, and the cap body 10
The coefficient of thermal expansion is matched with.

FIG. 2 is a fusion process diagram of this embodiment. First, as shown in FIG. 2A, after placing a glass tablet T such as a hard glass plate on one end side of the cap body 10,
As shown in FIG. 2B, when the glass tablet T is melted by heating from one end side of the cap body 10, a free curved surface due to the viscosity of the glass is formed on one surface Ta of the glass tablet T.

Next, as shown in FIG. 2C, the cap body 10 is turned upside down and the cap body 1 is turned upside down.
When the ring-shaped member 12 is dropped into the inside of 0 and then the glass tablet T is melted by heating again as shown in FIG. 2 (d), the free-form surface due to the viscosity of the glass is also formed on the other surface Tb of the glass tablet T. The lens 11 is formed using the viscosity of the glass.

According to this embodiment, after the ring-shaped member 12 is dropped inside the cap body 10, the glass on the inner side of the cap body 10 is heated and melted.
The unique effect that the lens shape and dimensional accuracy on the inner side of the cap body 10 can be stably obtained is obtained.
That is, as shown in FIG. 3, which is a partially enlarged view of FIG. 2D, the glass in a molten state is dammed by the ring-shaped member 12, and the molten glass is prevented from climbing up to the inner wall surface of the cap body 1. . Therefore, the height reduction of the lens 11 can be avoided, and the lens 11 having a dimension substantially equal to the inner diameter of the ring-shaped member 12 can be stably formed.

[0015]

According to the present invention, a ring-shaped member having an inner diameter equal to or larger than the inner diameter of the through hole is housed inside the cap body, and the ring-shaped member is brought into contact with the light-transmitting glass. The accuracy of the shape and size of the lens can be improved only by controlling the flow of the light transmitting lens during fusion bonding by the ring-shaped member.

[Brief description of drawings]

FIG. 1 is a structural diagram of an embodiment.

FIG. 2 is a fusion process diagram of an example.

FIG. 3 is a partially enlarged view of FIG. 2 (d).

FIG. 4 is a structural diagram of a conventional example.

FIG. 5 is a fusion process diagram of a conventional example.

FIG. 6 is a partially enlarged view of FIG. 5 (c).

[Explanation of symbols]

 10: Cap body 10b: Through hole 11: Lens 12: Ring-shaped member

Claims (2)

[Claims] 1. An airtight glass which is hermetically sealed by a lens (11) formed by fusing light-transmitting glass to a circular through hole (10b) formed in a cap body (10). In the lens cap, a ring-shaped member (12) is brought into contact with and fused to the light-transmitting glass around the lens (11) forming portion on the inner surface of the cap body (10). . 2. The inner diameter of the ring-shaped member (12) is substantially equal to or larger than the inner diameter of the through hole (10b), and the outer diameter of the ring-shaped member (12) is the cap. An airtight glass lens cap according to claim 1, characterized in that it is slightly smaller than the inner diameter of the cylindrical part of the body (10).