LETTER (SANITIZED)

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP79B00873A001900010066-2
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 5
• Document Creation Date: December 28, 2016
• Document Release Date: August 30, 2012
• Sequence Number: 66
• Publication Date: July 18, 1967
• Content Type: LETTER

? STAT
Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001900010066-2
47.
18 July 1967
Corning Glass Works
3900 Electronics Drive
Raleigh, North Carolina
Dear Mort:
Pursuant to our telephone conversations on IO and 13 July, I'm
sending you the information you requested about the image Intensifier
Screen and also the information I volunteered about the screen material
used on the Czechoslovak1an Mosaic Screen et EXPO 67.
The information on the Image Intensifier Screen is attached in the
form of our old Development Objectives. It's my understanding that you
have something you think may .be applicable 4.- I want to reemphasize the
point that we had to set this development aside pending advances in
the state-of-the-art, a higher priority requirement and/or more R&D funds.
However, we're always interested inlearning of new technology; so if
you believe that you have something of interest to share, you know we
would appreciate it,
On the second matter, I'll verify the information I gave you over
the phone as follows:
1. The rear projection screen material used on the Czech
Mosaic Screen System at EXPO 67 appeared to have much higher contrast
than any other I have seen.
2. I asked about the material and was directed to see
He informed me that the material did
have very high contrast and that he had discovered it in West Germany.
It was developed in a small company under the direction of
However, he purchased the material from:
STAT
STAT
STAT
STAT
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Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001900010066-2
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I hope youlll be able to obtain a sample of this material and eval-
uate it. The contracting officer will advise you of any contractual
implications of performing this evaluation under separate cover.
Attachment: (1)
Image Intensifier Serenirifoxnation
Sineerely yours,
ram. jhr
cc: C/ESB
Contrac-
DC/DS
DS file (chrono)
STAT
STAT
STAT
Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001900010066-2
Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001900010066-2
ei+
13 July 1967
(Retype of Document originally
dated 2 November 1964)
DEVELOPMENT OBJECTIVES
IMAGE-INTENSIFIEE
1. INTRODUCTION
These development objectives describe requirements for an image-
intensifier screen to be used for rear-projected images.
Rear-projection viewers have' come into standard use for scanning and
interpreting photo transparencies. Most of these materials are high resolu-
tion and require great enlargement before the human visual system can assess
the total information content. This enlargement, in turn, requires greater
projection lamp power in order to attain the necessary image brightness
over the entire viewing screen. Increased lamp power is accompanied by
greatly increased heat incident on the film so that it is distorted or
damaged. There are in existence various techniques for cooling at the film
plane, e.g... dichroic mirrors, fans, liquid gates, etc. In spite of these
techniques, there remains the heat vs image intensity problem in high mag-
nification projection of film transparencies which are static or slow moving
in the film gate.
It has been postulated that this problem might be solved by intensifying
the image at the viewing screen. Such a screen would require minimal power
in the projection illumination, but would produce a bright image for the viewer.
2. CONCEPT
2.1 Purpose. These objectives describe a development which would over-
come the heat versus image intensity relationship characteristic of high
magnification (in the order of 100x) rear projection viewers.
2.2 Scope. The primary objective is, that under nominal highlight
illumination of approximately 10 foot candles, the image-intensifier screen
should provide the viewer with an image of adequate gain and brightness
while exhibiting satisfactory performance in many other aspects, such as:
resolution, tone range, linearity, color temperature, viewing angle, response
time, size, life and cost.
A secondary objective is to provide a means for controlling modulation
of image contrast, such as tone-reversal and compression or expansion.
Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001900010066-2
Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001900010066-2
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3. GENERAL DESCRIPTION
The image-intensifier screen is intended for use on rear-projection
viewers, which would be used by one to four persons to scan and interpret
high-quality photo transparencies at various magnifications (ranging to
100X). The screen size on these viewers may be as large as 30" x 30".
The image-intensifier screen should be designed to require minimum modifi-
cation of existingviewers.
4. PRIMARY REQUIREMENTS
4.1 Gain The gain of the ITS must be such that light within the
range of 28000- 58000K, falling on the screen at intensity equal to one
foot-candle, causes a brightness of 50 foot-lamberts to be radiated through-
out a solid angle of 90? (centered on the axial ray)..' A greater gain is
desired--provided that it does not compromise other performance parameters.
4.2 Emitted Light.
4.2.1 Brightness. The ITS must be capable of emitting a maximum
brightness of 50 foot-lamberts; 200 foot-lamberts is the development
goal.
4.2.2 Linearity. Gamma. The emitted light must be directly pro-
portional to the incident light at all intensities. Gamma must ?
approximate unity (+ 10%).
4.2.3 Brightness should not vary more than 10% (from the theoreti-
cal) over the entire viewing area.
4.2.4 Brightness Distribution Lobe. The emitted light should be
of relatively uniform brightness (+ 10%) throughout a 90? solid angle
centered on the emergent axial ray.
4.2.5 Color Temperature. The emitted light must fall within
the color temperature range of 35000
- 5500?K.
4.2.6 Brightness Levels. The emitted light must display at
least ten different, visually distinguishable brightness levels when
excited by correspondingly varied incident illumination. As many as
twenty different distinguishable levels are desired.
4.2.7 Reflectance. The viewing surface of the ITS shall be de-
signed to minimize reflectance of ambient room light. This requirement
is of utmost importance: -ideally the viewing surface of the IIS should
have reflectance characteristics similar to those of black velvet, in
order that maximum modulation transfer can be preserved even in normal
room light.
Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001900010066-2
Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001900010066-2
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4.3 Resolution. The IIS shall be capable .of resolving 10 line pairs
per millimeter with a contrast of 100 to 1. The modulation transfer func-
tion at 10 lines/mm should be at least 90%: 20 lines/mm at 90% MTF is the
design goal.
4.4 Response Time. The IIS must reach 90% theoretical brightness
within 10 milliseconds of excitation and must fall below 10% of this bright-
ness level within 10 milliseconds of removal.
4.5 Signal/Noise Ratio. .No square inch of the IIS should exhibit a
signal/noise ratio less than 100.
4.6 Size. The thickness-and weight-to-area ratio of the IIS should
be approximately that of a conventional screen. This IIS may be bread-
boarded in 6" x 6" panels. One 12" x 12" operational panel must be delivered.
,Optional pricing for delivery of a 30" x 30" panel may be given. Feasibility
of producing the 30" x 30" units in volume must be indicated.
4.7 Life Expectancy. The IIS must be capable of operating at maximum
brightness (at least 50 foot-lamberts) for 200 hours, with no more than 10%
degradation in any of the specified performance parameters.
4.8 Power Requirements. The IIS should be adequately served by 110-
120 volt, 60 cycle, 15 ampere power supply. Normal fluctuations in the
voltage (+ 10%) should not perceivably affect performance.
5. SECONDARY REQUIREMENTS
The following requirements are to be considered if they do not compromise
those stated in section 4 (above): .
5.1 Contrast Modulation. If the capability is inherent, controllable
contrast modulation of the following types is desired:
5.1.1 Complete linear intensity reversal should be available
at the option of the operator.
be
5.1.2 Expansion and compression of the brightness range should
an option available to the operator.
5.2 Monochromatic Sensitivity. The IIS should be sensitive enough to
accept illumination from a narrow band of the visible spectrum or the near
IR and UV: 6328 A? laser illumination would be a logical consideration. If
?such were feasible, lens design could be optimized accordingly. In such a
case the gain requirements described in 4.1 would be modified correspondingly.
Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001900010066-2