Appeal 2007-3363
Application 10/342,711
James J. Powell et al., X-Ray imaging screen with process for
its preparation, U.S. Patent 5,107,125 (issued 21 April 1992)
(Powell).
In analyzing obviousness, the scope and content of the prior art must
be determined, the differences between the prior art and the claims
ascertained, and the ordinary level of skill in the art resolved. Objective
evidence of the circumstances surrounding the origin of the claimed subject
matter (so-called secondary considerations) may also be relevant. Such
secondary considerations guard against the employment of impermissible
hindsight. Graham v. John Deere Co., 383 U.S. 1, 17, 36 (1966), cited with
approval in KSR Int'l v. Teleflex Inc., 127 S. Ct. 1727, 82 USPQ2d 1385
(2007). Afga's Appeal Brief does not rely on any objective evidence of
secondary considerations.
The scope and content of the prior art
Hell teaches binderless storage phosphor screens with needle-shaped
phosphors. (Hell ¶0002.) The use of alkali metal halide phosphors in
storage screens was well known. Hell explains that their high crystal
symmetry makes binderless screens possible. (Hell ¶0005.) Hell's "highly
preferred" phosphors for binderless phosphor screens are CsX:Eu stimulable
phosphors, where X is bromide or chloride. (Hell ¶0026.) The most
preferred one is CsBr:Eu. (Hell ¶0031.)
Hell teaches making a binderless phosphor layer on a support using
physical-vapor deposition, thermal-vapor deposition, chemical-vapor
deposition, electron-beam deposition, radio-frequency deposition, and
pulsed-laser deposition. (Hell ¶0016.) In the specific example disclosed,
thermal-vapor deposition was used to make a CsBr:Eu phosphor layer on a
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