Ex Parte Perry et al

Board of Patent Appeals and Interferences

Mar 12, 2003

08859020 (B.P.A.I. Mar. 12, 2003)

The opinion in support of the decision being entered today was not
written for publication and is not binding precedent of the Board.

Paper No. 20

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte MICHAEL D. PERRY
and
BRENT C. STUART
__________

Appeal No. 2001-0238
Application No. 08/859,020
___________

ON BRIEF
___________

Before JEFFREY T. SMITH, PAWLIKOWSKI and MOORE, Administrative
Patent Judges.

MOORE, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 from the final
rejection of claims 1 - 11, which are all of the claims pending
in this application.
REPRESENTATIVE CLAIMS
Claims 1, 2, 10 and 11 are representative of the claimed
subject matter and read as follow:
1. A method for machining metals and alloys, comprising:
producing a pulsed laser output beam from a solid state
laser, wherein said pulsed output beam comprises a plurality of
Appeal No. 2001-0238
Application No. 08/859,020

laser pulses wherein said laser pulses have a pulse repetition
rate greater than 10 Hz and a wavelength in the range of 750 nm
to 10.7 microns, wherein each pulse of said plurality of laser
pulses has a pulse duration of 100 picosecond or less; and

directing said pulsed laser output beam onto a workpiece
comprising metal or alloy, wherein each said pulse converts
approximately greater than 0.1 micron to 1 micron of material of
said workpiece from a solid state to a plasma state, wherein said
material is removed from said workpiece by hydrodynamic expansion
of said plasma.

2. A method for machining metals and alloys, comprising:

producing a laser beam from a solid state laser; and
directing said laser beam onto a workpiece comprising material
selected from a group consisting of metal and alloy, wherein said
laser beam comprises a plurality of laser pulses, wherein said
laser pulses have a pulse repetition rate greater than 10 Hz and
a wavelength in the range of 750 nm to 10.7 microns, wherein each
said pulse has a pulse duration within the range of 10
femtoseconds to 100 picoseconds and a focused irradiance of
greater than 1012 W/cm2, wherein each pulse of said plurality of
laser pulses converts approximately greater than 0.1 micron to 1
micron of material of said workpiece from a solid state to a
plasma state, wherein said material is removed from said
workpiece by hydrodynamic expansion of said plasma.

10. An apparatus for machining metals and alloys,
comprising:

a solid state laser for producing a pulsed laser output beam
comprising a plurality of laser pulses wherein said laser pulses
have a pulse repetition rate greater than 10 Hz and a wavelength
in the range of 750 nm to 10.7 microns, wherein each said pulse
of said plurality of laser pulses has a pulse duration of 100
picosecond or less; and

means for directing said pulsed laser output beam onto a
workpiece comprising metal or alloy, wherein each said pulse
converts approximately greater than 0.1 to 1 micron of material
of said workpiece from a solid state to a plasma state, wherein
said material is removed from said workpiece by hydrodynamic
expansion of said plasma.

Appeal No. 2001-0238
Application No. 08/859,020

11. An apparatus for machining metals and alloys,
comprising:

a solid state laser for producing a laser beam; and
means for directing said laser beam onto a workpiece
comprising material selected from a group consisting of metal and
alloy, wherein said laser beam comprises a plurality of laser
pulses, wherein said laser pulses have a pulse repetition rate
greater than 10 Hz and a wavelength in the range of 750 nm to
10.7 microns, wherein each said pulse of said plurality of laser
pulses has a pulse duration within the range of 10 femtoseconds
to 100 picoseconds and a focused irradiance of greater than 1012
W/cm2, wherein each pulse of said plurality of laser pulses
converts approximately greater than 0.1 micron to 1 micron of
material of said workpiece from a solid state to a plasma state,
wherein said material is removed from said workpiece by
hydrodynamic expansion of said plasma.

The Reference
Pronko et al. “Machining of sub-micron holes using a femtosecond
laser at 800 nm,” Optics Communications, Vol. 114, pages 106-110,
January 15, 1995. (Pronko).

The Rejection
Claims 1-11 are rejected under 35 U.S.C. § 103(a) as being
unpatentable over Pronko.
The Invention
The present invention is said to provide a method for laser
cutting/machining of metals and alloys which achieves high
machining speed with extreme precision, negligible heat affected
zone, and no modification to the material surrounding the kerf.
The method is accomplished by focusing a laser pulse of between
10 femtoseconds to 100 picoseconds onto a surface to produce an
ionized plazma while the material to a depth of approximately 1
Appeal No. 2001-0238
Application No. 08/859,020

micon is unaffected by the removal of the material. (Appeal
Brief, page 3, lines 5 - 15).
Discussion
I. Preliminary Matters
A. Non-Entry of Amendment
The appellants have attempted to appeal the decision of the
examiner to not enter the amendment filed September 17, 1999.
See, e.g. page 9, lines 2-3 and page 15, line 16 - page 16, line
10 of the Appeal Brief. This issue is not properly before this
panel of the Board of Patent Appeals and Interferences; rather,
it is a petitionable issue. We have no authority to review that
decision. See In re Mindick, 371 F.2d 892, 894, 152 USPQ 566, 568
(CCPA 1967) (refusal of examiner to enter an amendment after
final rejection of claims is a matter of discretion; if there is
an abuse of discretion, the matter may be remedied by petition to
the Commissioner of Patents; Board of Appeals does not consider
the issue whether examiner's refusal to enter proposed amendment
after final rejection constituted an abuse of discretion); In re
Pavlecka, 319 F.2d 180, 188, 138 USPQ 118, 125 (CCPA 1963) (the
non-entry of amendments is a procedural matter outside board's
jurisdiction).

Appeal No. 2001-0238
Application No. 08/859,020

B. Priority Claim
The appellants have claimed priority to application serial
no. 08/584,522 (now US Patent 5,720,894) in a new declaration,
filed March 9, 1999 (see paper #8). The appellants assert that
support for the claimed subject matter is found within the
disclosure of that application and therefore Pronko is not
available as prior art as they are able to swear behind Pronko.
(Appeal Brief, page 9, line 17 – page 11, line 14).
The examiner states that nowhere in 5,720,894 is found a
disclosure of a method or apparatus for machining metal or alloys
nor support for removal of amounts of approximately greater than
0.1 micron to 1 micron. (Examiner’s Answer, page 3, lines 16-20).
We have carefully reviewed the as-filed specification of
application serial no. 08/584,522. At page 11, lines 7 – 19 the
following passage is found:
The description of the operation of the laser system with
respect to dental applications is for exemplary purposes
only and is not intended to limit the application of the
laser of the present invention. As will be described in
greater detail below, the laser system of the present
invention has application to a wide variety of biological
tissue removal processes as well as exceptional utility for
general material removal and micro-machining. Those having
skill in the art will immediately recognize the utility and
applicability of the laser system’s novel operational regime
to laser-tissue interactions in the general sense.

At page 31, lines 4-16, the following passage is found:

Although the ultrashort pulse duration high repetition rate
laser system of the present invention has been described in
Appeal No. 2001-0238
Application No. 08/859,020

connection with an exemplary dental drilling application, it
will be clear to those having skill in the art that the
laser system has operational characteristics that are
suitable for a very wide range of material removal
applications. For example, in the treatment of ear, nose,
and throat disorders, volumetric material removal is
required in various surgical procedures, such as middle ear
bone surgery, cholesteatoma, skull and jaw bone surgery,
selective removal of malignant tissue, and tympanic membrane
surgery.

Finally, at page 32, line 31 – page 33, line 3, we see:

Those skilled in the art will appreciate that the foregoing
examples and descriptions of various preferred embodiments
of the present invention are merely illustrative of the
invention as a whole, and that variations in wave length,
pulse duration, pulse repetition rate, as well as beam
energy density, may be made within the spirit and scope of
the invention. Accordingly, the present invention is not
limited to the specific embodiments described herein, but
rather is defined by the scope of the appended claims.

The appellants assert that this disclosure in the parent
case “described the use of the invention for general material
removal and for micro-machining;” that the claims in the parent
claimed the invention in a broad sense; and that all the
parameters of the invention claimed in the application on appeal
are shown in the parent application. (Appeal Brief, page 10,
line 18 – page 11, line 4). We disagree.
Claim 1 has several recited features, including using a
pulsed laser output beam from a solid state laser on a metal or
alloy workpiece to oblate into plasma 0.1 to 1 micron of the
metal or alloy by using a plurality of laser pulses which have a
pulse repetition rate greater than 10 Hz and a wavelength in the
Appeal No. 2001-0238
Application No. 08/859,020

range of 750 nm to 10.7 microns, and each pulse has a pulse
duration of 100 picosecond or less. While the parent application
discloses various ranges or power structures for a pulsed laser,
we are unable to find the essential claimed features here. The
appellants have made no effort to point to support in the
specification for the claimed subject matter, and our efforts
have failed to find any support for the claimed invention.
Accordingly, we agree with the examiner that the subject matter
as claimed is entitled to a priority date of May 20, 1997.
Turning now to the declaration of Michael D. Perry, we note
that it illustrates pages from laboratory notebooks recording
measurements from experiments on December 11, 1993; December 12,
1993, January 8, 1994, January 11, 1994, and February 3, 1994.
See, e.g. Declaration of Perry, page 2, line 5 – page 3, line 8.
However, we note that none of this information is contained
within the parent application (or, for that matter, the instant
application). Furthermore, other than the statement that there
were “extensive discussions” which led to “later work” which
formed the basis for the parent application, there is no evidence
whatsoever of due diligence to the filing date of the
application, as required by 37 CFR § 1.131(b). Consequently, even
were we to find the earlier filing date, the declaration would be
Appeal No. 2001-0238
Application No. 08/859,020

insufficient under Rule 131. Pronko, therefore, remains a valid
reference.
II. The Rejection
The examiner has found that Pronko discloses a method of
machining metals including producing a pulsed laser beam from a
solid state laser at a repetition rate of 1 kHz, a wavelength of
800 nm and a pulse duration of from 150 femtoseconds to 10
picoseconds; directing the beam to a silver metal workpiece; and
each pulse removing about 0.05 microns of material via
hydrodynamic expansion of plasma. The examiner has also found
that no damage occurs outside the heat affected zone of about 5.8
nm and the entire heat affected zone is removed; allowing no
thermal transfer beyond the removal depth. (Paper #5, page 3,
lines 4-12).
The examiner has also found that Pronko shows that greater
amounts of material can be removed by using longer pulse widths,
the examiner concludes that it would have been obvious to one of
ordinary skill in the art at the time the invention was made to
produce a removal depth per pulse of from 0.1 - 1 micron by
employing a somewhat longer pulse width than the 200 femtosecond
pulse illustrated by Pronko. The examiner also concludes that it
would have been obvious to one skilled in the art at the time the
invention was made to increase the beam energy to an irradiance
Appeal No. 2001-0238
Application No. 08/859,020

of 1012 W/cm2 to speed machining or form deeper features as the
material removal rate is proportionate to the beam energy. (Paper
#5, page 3, lines 17 – 27).
The appellants counter that the claimed method results in
the conversion of workpiece to plasma for any pulse duration less
than 100 picoseconds, contrary to the logic that it would be
necessary to increase the pulse width to produce an increase in
material removal (Appeal Brief, page 12, lines 1 – 12). The
reasoning is that Pronko is acting in a low power range
(approximately 1010-1011 W/cm2) and only converting material to
vapor, not plasma. According to the appellants, only a
negligible additional amount of material can be removed by
increasing the pulse width in the fully ionized plasma realm of
1012 W/cm2, as the additional energy simply goes into the plasma.
(Appeal Brief, page 12, line 13 – page 13, line 8).
Claims 1 and 10 contain, in terms of beam power, the
limitation that each pulse converts approximately greater than
0.1 micron to 1 micron of material of said workpiece from a solid
state to a plasma state, wherein said material is removed from
said workpiece by hydrodynamic expansion of said plasma. Claims
2 and 11 require a focused irradiance of 1012 W/cm2.
We find that the Pronko reference discloses the formation of
plasma (page 107, column 1, line 4) during the laser oblation
Appeal No. 2001-0238
Application No. 08/859,020

process and that the optical emissions are proportional to the
amount of material removed which is a function of incidence
fluence (Id., column 1, lines 3-9).
However, Pronko discloses a system producing pulses with an
energy of 300µJ (p. 106, column 1, line 19) focused on an area of
~6.0µm. In the examples, the pulses contain ~40 nJ (p. 108,
column 2, line 16) or 250nJ (page 109, column 1, line 6). Both
the examiner and the appellants appear to concur that these
amounts are lower intensity (< 1010-1011 W/cm2)(Appeal Brief, page
12, lines 13-16)(about 1.4 x 1010 W/cm2)(Paper #5, page 3, lines
15-16) than that required by claims 2 and 11 (1012 W/cm2).
The minimum intensity of claims 1 and 10 is not expressly
recited other than by the functional limitation of the
requirement of hydrodynamic expansion of plasma. The
specification submits that such values are typically 1014 W/cm2
for 100 femtosecond pulses (page 13, lines 9-10) but also states
that the minimum laser focused requirement is 1012 W/cm2(page 8,
lines 7-12). Consequently, we interpret claims 1 and 10 as also
requiring a minimum focused laser irradiance of greater than 1012
W/cm2.
The examiner is of the opinion that a simple power increase
is obvious in order to form deeper features where needed, or to
speed machining when using repetitive pulses at a single location
Appeal No. 2001-0238
Application No. 08/859,020

(Paper #5, page 3, last 4 lines). We disagree. The point of
the Pronko reference is to demonstrate that the shorter pulse
widths have a greater resolution for use in ablation (Pronko,
page 106, column 1, first paragraph).
We are, therefore, unable to agree with the examiner’s
position that one of skill in the art would be motivated to
increase the power by at least about a factor of 10 to speed
machining, when the reference itself is concerned with the
resolution of the ablation and the reduction of diffused heat.
Consequently, we shall reverse this rejection.

REVERSED

JEFFREY T. SMITH )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
BEVERLY A. PAWLIKOWSKI )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
JAMES T. MOORE )
Administrative Patent Judge )

Henry P. Sartorio
Deputy Laboratory Counsel for Patents
Lawrence Livermore National Laboratory
P.O. Box 808 L 703
Livermore, CA 94551

JTM/ki