Appeal No. 95-2231
Application No. 08/114,285
a) introducing CF into said lasing gas or gas mixture
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and reacting said CF with said oxygen impurity which
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accumulates in said lasing gas or gas mixture, said CF being
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introduced in an amount effective to produce one or more
compounds which are condensable with refrigeration means; and
b) condensing said one or more compounds produced in
step a) in a cryogenic trap with refrigeration means and at a
temperature sufficient to condense said one or more compounds
substantially without condensing said lasing gas or gas
mixture therewith, thereby removing said oxygen impurity from
said lasing gas or gas mixture, thereby extending the
operating life of the excimer laser.
The references relied on by the examiner are:
Bedwell 5,090,020 Feb. 18,
1992
Reid et al., (Reid) “Excimer Lasers: Current Trends and Future
Directions,” SPIE O-E/LASE, pp. 1-8, January 1989,
(hereinafter referred to as “Reid”).
Claims 16 through 19, 21 through 24, 31 and 32 stand
rejected under 35 U.S.C. § 103 as unpatentable over Bedwell in
view of Reid.
We reverse.
The examiner acknowledges that:
The difference [sic, differences] between the
Bedwell reference and the claims are as follows: it
does not teach operating the cooling system while
the laser is on and does not discuss deliberate
introduction of [oxygen or CF impurity] materials
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into the system. See Answer at page 3.
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