HIGH RESOLUTION SCREEN

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04770A002900020052-3
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 4
• Document Creation Date: December 28, 2016
• Document Release Date: August 30, 2005
• Sequence Number: 52
• Publication Date: August 24, 1964
• Content Type: REPORT

Approved For Release 2005/1
STAT
HIGH RESOLUTION SCREEN
August 24, 1964
A special projection lens was required for this program
in order to et good resolution on the screen for both
ultraviolet (3650A) and visual green (5461A).
has completed the design and the order for mane acture of
the elements was placed with last week.
The lens has an 8.034-inch equivalent focal length and will
project a 2-1/4 x 2-1/4-inch format onto a 30 x 30-inch
screen.
With all spherical elements, the lens must be stopped down
to about x'/5.6. I Iwill use all spherical elements for
initial testin an ey expect to receive the lens from
about October 28. With this lens delivery
it will be November before the feasibility demonstration
can be made.
By as herizin two elements the lens can be opened up
to 1/2.8. expects to aspherize the lens after the
initial tests if more brightness is needed. The lens has
six elements plus a field flattener near the film gate,
and 0 hopes to get 35% to 40% transmission efficiency
of the UV.
has completed his
investigation of phosphors and a final report is being
prepared. The balance of the work will be aimed at pro-
ducing samples for the feasibility demonstration.
A mixture of organic dyes was most successful. They produce
a green to blue green visual color when excited by UV.
There was considerable discussion regarding requirements
of the feasibility demonstration. The chief obstacle to
a full-scale demonstration is the size of the screen that
can be prepared. The laboratory coating techniques will
only produce samples about 2-inches square. With some
additional arrangements, they can coat samples up to
about 12-inches square, but they will probably not be
very uniform.
Declass Review by NGA.
STAT
STAT
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High Resolution Screen -2- August 24, 1964
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this contract.
It appears that a full-scale 30 x 30-inch screen cannot
be prepared without considerable tooling expense, perhaps
on the order of I I which is not within the scope of
So, the question is: What must the feasibility demonstra-
tion demonstrate? In my opinion it must demonstrate:
A. Screen Resolution
This can be done by a reduction projection of a resolution
target on a 2-inch square screen sample. The illumination
can be from a small UV lamp and the visual light from the
screen can be observed with a microscope. It is anticipated
that over 100 lines per millimeter resolution at the screen
will be obtained.
B. Gray Scale Rendition
This can be done by illuminating a 2-inch square
screen sample with UV and placing a standard density step
strip over the sample so that it intercepts the UV. It
is anticipated that individual density steps will be
readily observed over at least half the 21 steps of a
standard strip.
C. Brightness Variation with Viewing Angle
A larger screen would be desirable to demonstrate this,
feature. A continuous tone image could be projected onto
6-inch square (or larger) screen which could be viewed from
any angle. It is expected that the brightness will remain
almost constant regardless of the angle from which the
screen is viewed.
D. Maximum Phosphor Brightness Capability
has not found any limitation on how brightly the
phosphor will glow. There must be a saturation point, but
they have not observed it yet. As the UV brightness in-
creases, the visual brightness also increases. This can
be demonstrated by intense UV flooding of a small coated
screen and observing the increasing brightness as the screen
is moved closer to the source. It is anticipated that
phosphor brightness can be increased to the dazzling point.
T. General Suitability for Rear Projection Viewing
For general suitability, the largest possible screen
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High Resolution Screen -3- August 24, 1964
up to 30 inches x 30 inches is desirable. Various people
should try viewing to determine qualitatively the effect
of the transparent screen, the color, ambient room light
levels, group viewing. A very important point to determine
is whether a fixed projection magnification can be used
for general viewing and a small auxiliary magnifier used
to resolve fine detail on the screen.
There are several important items that this program does
not do and has not attempted to do. One is the lamp bright-
ness. At present there is no substitute for brute force
power and multi-kilowatt lamps are needed for adequate
brightness in shadow areas.
Another is automatic projection dodging. The highlight
areas may be dazzling bright and the shadow areas under
illuminated.
At this point in time, I have reached two conclusions and
I will pass them on as recommendations. I am assuming
that the feasibility demonstration will be technically
successful. This, I believe, is well assured. Whether
or not it will be convincing without a large screen display
is not at all assured.
Assuming a posture of success, however, there are two
areas which urgently need defining.
A. Further phosphor coating investigations.
B. Configuration of an experimental or prototype projector.
Further phosphor coating work I suggest be a long-term
program covering:
Theoretical study of the fundamental energy conversion
process and its efficiency. (Perhaps some research money
should be solicited for support of this phase at a univer-
sity.)
Search for phosphors of greater brightness and establish-
ment of precision brightness measuring techniques which
are simple and quick.
Measurement of phosphor fading and prediction of phosphor
life.
Search for color variations and color control by mixing.
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August 24, 1964
Preparation of multilayer, multicolor phosphors.
Determination of the effect of different coating techniques.
Comparison of the effect of opaque and transparent phosphors.
An experimental projector perhaps should be a room type
installation rather than a machine. I suggest it concentrate
on:
Preparation of large screens of uniform quality up
to 6-ft high by 12-ft wide.
Utilization of large kilowatt lamps with special
heat control and dissipation to keep the film gate
cool.
Use an existing film transport.
Production of a large -]-/stop projection lens with
high UV transmission efficiency for UV region only
and which will cover a full 9-inch wide aperture.
0
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