Method for Manufacturing a Stripline Laser

The present invention is directed to a method for manufacturing a stripline laser which is composed of a plurality of constituent parts including a housing and a discharge space which is preferably a rectangular cross section. The method includes soldering at least two of the parts together when joining the parts together.

U.S. Pat. No. 4,939,738, whose disclosure is incorporated herein by reference thereto and which priority from German Application 37 29 053, discloses a stripline laser which is formed by a plurality of parts which are joined together.

The object of the present invention is to provide a method for manufacturing a stripline laser composed of a plurality of parts, which method involves a low manufacturing cost or outlay and provides a stripline laser with a lengthened operating duration, which is beyond 10,000 hours of operation.

To accomplish these goals, the present invention is directed to an improvement in a method of manufacturing a stripline laser that is composed of a plurality of constituent parts defining a discharge space which is preferably a rectangular cross section and a housing, said method including soldering together at least two of said parts. The improvements are that the step of soldering uses a soft solder, subsequent to the soft soldering, cleaning the interior of the laser by exciting a plasma therein to create a plasma treatment, subsequently treating the interior of the laser with a second plasma treatment in a gas composition that is harmless for the operation of the laser to passivate the interior of the laser and limiting the temperature of the parts joined by the soft soldered to a temperature below approximately 150.degree. C. during each plasma treatment.

Utilizing soft soldering as a solder connection in a laser is not possible without further ado. After a soft soldering process, water residues, hydrocarbons and other contaminants will remain in the laser, and these contaminants cannot be baked out at a maximally allowable temperature of the soft solder points, which is approximately 150.degree. C. A cleaning and baking to remove the contaminants has succeeded, according to the present invention, in that the interior of the laser is first cleaned in an oxidizing atmosphere with a separate plasma treatment and is then subsequently passivated in a gas composition that is harmless for the operation of the laser. Given CO.sub.2 stripline lasers, a plasma that contains O.sub.2 is suitable for the cleaning operation, and this advantageously occurs by excitement between an electrode, which is at an above-ground potential, and the housing. Insofar as this is not possible, the use of an auxiliary electrode that can remain in the laser is recommended.

The excitation of the plasma advantageously occurs without electrodes on the basis of a pulsed HF having a frequency that can extend up to the GHz range.

In addition to cleaning, the first plasma treatment in an atmosphere containing O.sub.2 is preferably composed of pure oxygen or a mixture of oxygen and helium will also effect a forming on the inside walls. In the second plasma treatment in the case of a CO.sub.2 laser, CO.sub.2 is advantageously blown in and the plasma treatment is continued until the interior of the housing has been completely passivated, for example so that the exposed surfaces are saturated with CO.sub.2 and, therefore, no longer will produce any change in the CO.sub.2 concentration in the laser housing during operation of the laser.

An advantageous development is that the plasma that produces the intense ultraviolet radiation in the wavelength below 200 nm is excited in the laser. This produces an especially fast and thorough cleaning. Parts especially highly exposed to the laser plasma during operation, such as, for example, electrodes, are advantageously separately exposed to the desired plasma treatment. As a result thereof, these are cleaned and passivated to an especially pronounced degree.

Other advantages and features of the invention will be readily apparent from the following description of the preferred embodiments, the drawing and claims.

The FIGURE is a flow sheet for the method of the present invention.

The principles of the present invention are particularly useful in a method for assembling parts to form a laser. In this method, the laser parts are assembled in the usual way. Inventively, at least one part of the laser parts is joined to another by a soft soldering. After the soft soldering, a plasma treatment in a gas containing O.sub.2 is implemented. This gas, if needed, may contain helium or other similar additives which will guarantee the optimum oxidation rate. As a result of this treatment, the walls are cleaned and formed, i.e., oxidized. On the basis of an additional plasma treatment in a CO.sub.2 for a CO.sub.2 laser, additionally, the walls are passivated, for example CO.sub.2 is agglomerated to the walls up to the saturation, so that no change in the partial CO.sub.2 pressure in the laser will occur during later operations of the closed laser. After this treatment, the laser can be filled and closed vacuum-tight.

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.