Appeal 2007-0835
Application 09/950,778
We AFFIRM.
I. BACKGROUND
The invention relates to a luminescent intensifying screen (X-ray
conversion screen). Such screens are used in radiography systems. In
common medical radiography systems, the screens are fixed inside a cassette
so that a double-side coated silver halide emulsion film (X-ray film) can be
inserted in-between the two screens (Specification 2:31-36 and 15:12-19).
In such systems phosphor within the intensifying screen converts X-rays into
light of corresponding intensity so the light irradiates the light-sensitive
silver halide photographic emulsion layer of the X-ray film (Specification
2:20-30). The image is later developed in the film (id.). Combinations of a
single sided film with one screen are also known (Specification 3:1-8).
Because the screens are reused, they are subject to scratching during loading
and unloading of the X-ray film. To increase durability, the screens include
a protective coating over the phosphor layer (Specification 3:15-21). The
protective layer preferably has a relief structure that reduces friction and
prevents sticking during loading and unloading of the X-ray film from the
cassette (Specification 3:25-29). Forming such relief structures to an
optimum surface roughness by embossing the protective layer was known in
the art (Specification 3:34-4:4 referencing EP-A 0 510 754).
Appellant’s screen, as claimed, includes a protective coating
containing titanium dioxide in a binder of urethane acrylate, the protective
coating having a particular surface roughness. Claim 1, the only
independent claim, is illustrative of the subject matter on appeal:
2
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