Page 41 - Chalcogenide Glasses for Infrared Optics

20 Cha pte r T w o

Research, moved to the TI EO Division, and took over the glass pro-
duction program. His efforts succeeded and yields improved, leading
to decreased cost. Standard production became 7-kg plates 12 in × 12 in
of TI 1173.
In the late 1960s and early 1970s, passive 8- to 12-µm systems
began to be produced in small numbers, mostly for the Air Force or
Navy. The numbers were in the hundreds, corresponding to the num-
ber of airplanes. Notably was the system for the B52 made by Hughes
Aircraft. The potential numbers reached thousands when the cus-
tomer became the Army. The Army embraced a common module approach
whereby different companies could all build from the same design.
There would be three programs: the ANTAS for the Infantry, the Tank
Thermal Sight, and TADS PNVS for the helicopter. All companies
could compete, and the winner’s design would be adopted as the
common module. Since the wavelength range was wide, color correc-
tion would be necessary which meant that a second optical material
would be needed to go along with germanium, by then the industry
standard. The TI design used TI 1173 with germanium. TI won the
first two programs. The Army became aware of the fact that TI was
the only source of the glass used in their common modules. The third
program, TADS PNVS, had not been decided. It became obvious to
the author that a second source of glass would be needed. Early in
1977, the author gave notice to TI that he planned to leave the com-
pany. He was called in and told by TI that he would be allowed to
produce the glass. The Army was told that there would soon be a
second source. However, the Army awarded the TADS PNVS con-
tract to Martin Marietta in 1977. Thus, for two of the programs the
Army was committed to a design that used a patented glass as the
second material, not available to competitors. The alternate glass, TI
20, was no longer in production at TI. Clearly a second source of glass
was needed to ensure the success of the Army common module
approach.
The author left TI in 1977 and in May founded Amorphous Mate-
rials (AMI). Very soon he found TI had changed its mind and would
not license Amorphous Materials to produce TI 1173 glass. The deci-
sion was made to produce the TI 20 germanium-arsenic-selenium
glass at AMI because its physical and optical properties had been
25
fully studied and published in a government report. Besides, TI 20
was a better glass than TI 1173. The glass was not and could not be
patented. Next, AMI had to convince the Army that producing this
glass would save the concept of the common module approach. It took
over a year to persuade the Army to help AMI. The effort was sup-
ported through a three-year Manufacturing Methods and Technology
Program funded by the Army through the Night Vision Laboratory at
Ft. Belvoir. Amorphous Materials renamed the glass composition
Amtir 1 and went on to supply Magnavox, Kollsman Instruments,