Method for Securing Optical and Electro-Optical Components

The present invention is directed to a method for securing components such as optical and electro-optical components together.

Up to the present, the fastening of components such as optical or electro-optical components together occurred by means of utilizing either mechanical clamps or by bonding. Due to the use of a manipulator which holds the parts in the desired position, these methods generally impose stresses on the components. Furthermore, when utilizing glue connections, care must be taken so that gases are not emitted which may injuriously effect the electro-optical components.

The present invention is directed to providing a method for fastening optical and electro-optical components in random positions or in aligned positions to one another without utilizing undesired adhesives. This object is achieved by a method of fastening optical and electro-optical components which method includes the steps of positioning a component in the desired position relative to a base member, and securing the components to the member by laser welding.

Preferably, the component is either secured directly on a weldable support member that is positioned and welded to the base member by laser pulses or is secured on an intermediate carrier that is secured to the support member which is then welded to the base member. The step of positioning the weldable support member and base member provides a gap therebetween which has a thickness in a range of 50 to 250 .mu.m.

In order to prevent the heat of welding from being conducted towards the center of the weldable support member, the support member is preferably provided with means for forming a high resistance to heat conduction which means comprises either a melt nose or a hole. These weldable support members may be a metal support member and also the base member may be a metal member. However, the base member may be composed of silicon.

If an intermediate carrier is utilized, preferably it is a silicon disk, which is provided with V-shaped grooves such as by etching, to receive optical components such as light waveguides, laser diodes and optical miniature components.

The weldable support member should be formed of a material which has the slightest volume change during the welding operation and preferably the weldable support member and an intermediate carrier if used have comparable coefficients of thermal expansion.

FIG. 1 is an end view showing the positioning of an intermediate carrier, a weldable support member with a base member in accordance with the method of the present invention;

FIG. 2 illustrates the arrangement of FIG. 1 after welding;

FIG. 3 is a partial perspective view of an embodiment of the member having a welding nose for a welding point; and

FIG. 4 is a partial perspective view of a support member exhibiting a hole which provides a welding point.

According to the proposed method, optical and electro-optical components are fixed individually on a member or secured together by means of laser welding. To accomplish this method, the component to be attached is placed either directly on a support member 3 or on an intermediate carrier 2 which in turn is secured to the weldable support member 3. If an intermediate carrier 2 is utilized, it may be, for example, a silicon disk which may be provided with grooves such as by etching for receiving the component. The weldable support member 3 is preferably a metal material which has a low volume change during the welding operation, and, an example of this type of material is sold under the trade name Vacon. The weldable support member 3 in turn is welded to a metal base body or member 4. As illustrated in FIGS. 1 and 2, the support member 3 is positioned with a bottom surface 30 above a surface 41 of the body 4 with a gap 34 which has a thickness range of 50 .mu.m to 250 .mu.m. Prior to welding, adjustment between the members 3 and 4 in the plane of the gap 34 can be easily made.

The securing of the support member 3 to the body 4 is carried out by welding which welding step utilizes short laser pulses which melt material from the metal support member 3 in such a manner that the base body 4 and support member are connected to one another, for example, as illustrated at points 22 in FIG. 2. Preferably, the welds are carried out in at least three points.

The metal support member 3 may be designed to have means which provide high thermal resistance to the heat conduction from a point of welding toward the center of the support. This means can be formed as illustrated in FIG. 3 by a melt nose 31 which extends from an edge of the support member 3' to form a welding edge or point 35 or by providing a hole 32 adjacent a point 36 where the welding laser beam will be directed in the support member 3". Thus, the welding operation represents practically no mechanical loading for the manipulator and no thermal loading for the environment.

The intermediate carrier 2 is preferably a silicon disk, which has a groove 21 and serves as a carrier and fastening element for light waveguides, laser diodes, receiver diodes or optical miniature components. Each groove 21 is preferably manufactured by means of anisotropic etching. The metal support member is preferably of a material with a low volume change during the welding operation and particularly at the temperatures that are created. In addition, the member 3 has a thermal expansion coefficient which is comparable to the material of the intermediate carrier 2 and/or of the components.

Although various minor modifications may be suggested by those versed in the art, it should be understood that we wish to embody within the scope of the patent granted hereon, all such modifications as reasonably and properly come within the scope of our contribution to the art.