DIRECT IMAGE VIEWER, SPECIFICATION FOR

Document Type: 
Document Number (FOIA) /ESDN (CREST): 
CIA-RDP78B04747A001500020042-8
Release Decision: 
RIPPUB
Original Classification: 
K
Document Page Count: 
16
Document Creation Date: 
December 28, 2016
Document Release Date: 
February 13, 2002
Sequence Number: 
42
Case Number: 
Publication Date: 
July 10, 1964
Content Type: 
OUTLINE
File: 
AttachmentSize
PDF icon CIA-RDP78B04747A001500020042-8.pdf479.1 KB
Body: 
Approved For Release 2002/06/17 : CIA-RDP78B04747A001500 to 200 8-7506 STATINTL 10 July 1964 S DECLASS REVIEW by NIMA/DOD STATINTL Approved For Rel STATINTL ApprovedForR ase 2002/06/17: CIA-RDP78BO4747AO01500 O-75OE6TATINTL 10 July 1964 0 to 1.1 This specification describes the performance and technical characteristics of an Experimental Direct Ii,.age (High Resolution) Viewer. The Direct Image Viewer employs a unique optical approach, involving diffraction gratings, to provide an observer with an enlarged aerial image which can be viewed simultaneously with both eyes. 1.2 Major features of this viewer include the elircmina- tion of performance limitations imposed by the use of rear projection diffusion screens, and the achievement of high magnification viewing qualities comparable to advanced micro- scope viewing objectives. Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 STATINTL S STATINTL 0 2.1 The following drawings form a part of this speci- fication: 0 Dwg. 11o. 7506L1 Layout Dual Magnification, Direct Image Viewer Dwg. No. 7506L2 Assembly, YY Translator, Direct Image Viewer Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 Approved For Release 2002/06/17 : CIA-RDP78B04747A001500020042-8 9 3.1 Design - The overall configuration of the Experi- mental Direct Image Viewer specified herein shall be in general conlorr;lance with Drawing No. 7506L1. The viewer si-all employ materials of highest commercial quality consistent with its intended performance and speci- fied operating environments. STATINTL 3.2 Performance Characteristics - The performance charac- teristics of the Experimental Direct Image Viewer shall consist of tYe following general values: 3.2.1 Magnification - Dual individual magnifications of 5X and 50X. S 3.2.2 Observable Film Area - The observable film area shall consist of a nominal two (2) inch by two (2) inch square area in the film plane at 5X magnification, and two-tenths inch by two-tenths inch square area in the film plane at 50X magnification. 3.2.3 Film Size - The viewer shall possess a capa- bility f r viewing single frames of either 73 r.jn or ' nch film chips. 4.4 5 3.2.4 Exit Pupil Size - The nominal size of the composite exit pupil shall be 3.5 inches square. 3.2.5 System Resolution - At 5X magnification, the Experimental Direct Image Viewer shall be Approved For Release 2002/06/17?CIA-RDP78B04747A001500020042-8 Approved For Release 2002/06/17 : CIA-RDP78B04747A001500020042-8 capable of providing a system AWAR resolution of 60 lines per millimeter over the used field when referred to a high contrast target in the object plane. At 50X magnification, the viewer shall be capable of providing aurr of 200 OA bi$/ s - lines per millimeterpat the film plane with a high contrast target while employing commer- cially available lens. The resolution goal of the system when operating at 50X shall be 200 lines per millimeter as viewed in the object plane for a low contrast (1.6:1) target. 9 0 3.2.6 Light Intensity - The lamp intensity shall be variable and of sufficient brightness to allow the measurement of a 0.05 density difference over a required density range of 0 to 1.8. As a design goal, the viewer will provide a capa- bility of measuring a desirable density differ- ence of 0.02 over a density range of 0 to 2.5. X 3.2.8 Film Positioning - The viewer shall incorporate a provision for remote film positioning through X and Y translations to permit full coverage view- ing areas for either 70mm and 5-inch film chips. 3.2.7 Illumination Spectrum - The illumination of the viewer system shall be contained *o a narrow band within the 450-550 millimicron portion of the spectrum. . . 5 O ,,, G~ ~I r 1 _ C e d 3.2.9 Focusing - A manual fine focus controll shall be provided for each viewer lens magnification. 3.2.10 Film Temperature - The temperature of the film when mounted in the film plane of the viewer dur- ing operation shall not exceed ambient (75?F.) by more than 20?F. /I ~NQ--,-A Approved For Release 2002/06L17-: CIA-RDP78B047477=0J% . Approved For Release 2002/06/17 : CIA-RDP78B04747A001500020042-8 3.2.11 Viewer Controls - The Experimental Direct Image Viewer shall contain a set of viewer controls, front panel mounted, consisting of the following: 3.2.11.1 Power - ON/OFF aflumewb&r 3.2.11.2 hfttti Intensity 9 3.2.11.3 Magnification Selector, 5X and 50X .3.2.11.4 Lens Focus, 5X and 50X 3.2.11.5 Film Translation + one inch 7 + one inch Y 3.2 12 Power Consumption - The power consumption of the viewer shall be approximately 800 watts of 110 volts, 60 cycle, electrical power. 3.2.13 Physical Size - (Reference STATINTL Dwg. No. 7506Ll). The viewer shall consist of the following gen- eral dimensions: Length - 66 inches, height - 26 inches, width - 29 inches. ;14 Weight - The weight of the viewer shall be approximately 150 pounds. 3.3 Theory of Operation - In direct viewing optical instru- ments, such as a microscope, the exit pupil is small, requiring that the operator place his eye close to the eye piece for satis- factory viewing. The present Experimental Direct Image Viewer, with its larger optical elements and diffraction grating, enlarges the exit pupil in a manner that the operator may view with both eyes the image and still have adequate head movement. In the absence of employing diffraction gratings in the present viewer, a single small exit pupil would exist, which would restrict the operator to the use of a single eye and no head movement when viewing at high magnifications. Through the insertion of the -5- Approved For Release 2002/06/17 : CIA-RDP78B04747A001500020042-8 Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 gratings in the optical path, and the use of a narrow portion of the spectrum, many exit pupils are created, which when arranged side by side and placed both above and below one another, form a matrix of exit pupils in space providing an effective viewing area of 3.5 inches square, where the operator may place his eyes for viewing. This unique approach results from the use of a special field lens, and specially designed and built set of diffraction gratings. Dear monochromatic light must be used in the viewer, or the diffraction characteristics of the gratings will produce a rainbow of images between matrix units (exit pupil images). 3.4 Technical Details 3.4.1 Viewer body, optical supports, and controls - 0 3.4.1.1 Chassis - The viewer frame will be con- structed from aluminum jig plate, and rigid mounts will be supplied for all optical elements. The large field lens will be of a split design, and flange mounted to one-inch thick plates. The diffraction gratings will be mounted between the field lens elements and their one-inch separated flanges. 3.4.1.2 Film support and X-Y translation - The film support system, as shown in STATINTL Dwg. No. 7506L2, accomo- dates both 70mm and 5-inch film chips. The film will be held by a vacuum to a flat glass plate free of striations. The glass platen will be mounted on a mechanical mechanism which will provide controlled X and Y movement of 2 inches and translate the film 9 inches in X to change magnification. Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 3.4.1.3 Objective lens mounting - The two lenses will be flange mounted with the position of the flange being manually adjustable for fine focus. i 3.4.1.4 Auxiliary equipment - Two pieces of equipment will be placed within the viewer: (1) The light source power supply will be repackaged and mounted along one side of the viewer enclosure; (2) A small vacuum pump will be mounted so as not to induce any vibration to the optical path. 3.4.1.5 Viewer Housing - The viewer housing and enclosure will have a hinged section at the rear for access to the mechanism and for inserting film and lamp replace- ment. The front panel will contain the controls and provide the proper mask around the field lens and gratings. ? 3.4.2 Viewer Optics 3.4.2.1 Field Lens - A symmetrical design multi- element, 15-inch diameter, field lens will be used. The lens will image the exit pupil of the objective lens 20 inches from its rear nodal point. The lens shall be of a sufficiently high quality as not to degrade the high resolution image requirements of the viewer. 3.4.2.2 50X Magnification Components - A large aperture photographic lens will be used -7- Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 with a modified exit pupil producing a square opening. The resolution of the viewer is dependent upon this lens, and the best commercially available lens with an f number approaching unity will be used. A multi-element condensed system will be used to concentrate the light to the small 0.2 x 0.2 inch square film area while filling the objective lens. ? Field flatteners shall be employed to pro- vide field curvature for optimum field lens operation. 3.4.2.3 5X Magnification Components - A commer- cially available 8.5 inch focal length lens will be modified to contain a square exit pupil equal in size to the 50X lens case. ? The condenser system to be employed with this lens will concentrate and illuminate a 2 x 2 inch square area evenly. Separate field flatteners will be used for the same purpose employed with the 50X system. Two additonal small mirrors will be inserted in the path, one before and one after the lens to provide the dual 5X magnification. The mirror in front of the lens is movable to permit insert- ing it or removing it from the optical path. With film translation, the two magnifications are obtained. Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 3.4.2.4 Light Source - Two lamps and reflectors shall be employed, one for each lens. In addition, special interference filters will be employed to provide the narrow spectrum required. 0 ? 3.4.3 Diffraction Grating - In order to obtain the unique optical multiplication of exit pupils required, special diffraction gratings are required. Two gratings are employed to diffract the light into a multiplicity of exit pupils dispersed in two directions 900 apart, thus providing a matrix of exit pupil images. 3.4.3.1 For the prescribed magnification levels and the size of the multiple exit pupil required, a minimum of nine (9) orders of diffraction are required, a central order and four (4) on each side. The difficulty of the grating design is that all orders should receive the same amount of energy so that each exit pupil appears of the same brightness to the observer. 3.4.3.2 The gratings shall be of a 10 x 10 inch ruled surface, which influences the field of view of the system and the observable film size. Special ruling techniques are required and will be used to produce these gratings. 3.4.3.3 The light is diffracted by one grating in one direction, and then each diffracted exit pupil is spread out in the other direction by a second grating. The Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 cascaded diffraction gratings produce a decrease in light intensity, which is then enhanced by the use of a narrow band light source. Compensation is pro- vided in the condensers, high intensity lamps and the small f/number projection lens at the high magnification. 3.4.3.4 The nominal angular deviation of the various orders shall be: First order 1 0 94 Second order 2 0 18' Third order 3? 27' Fourth order 4? 35' The tolerance for each of the above devi- ations shall be + 10% of the above angles. 3.4.3.5 Intensity variations throughout the nine orders shall be no greater than 40% be- tween adjacent orders and no greater than a 2:1 ratio between the lowest and highest order in the nine central orders. ? 3.4.3.6 The transmission of the order which trans- mits the minimum amount of light shall be at least ?/Tof the light intensity falling on an individual grating. 3.4.3.7 The glass quality to be used in the manu- facture of the diffraction gratings shall be greater than striae free through the faces. 3.4.3.8 A maximum of 10 arc minutes of slope error shall be a permissible planeness (figure) of the glass. Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 0 ? 4.0 QUALITY ASSURANCE PROVISIONS 4.1 The optical components will be inspected and tested to demonstrate compliance to the performance requirements stated in Section 3.2. 4.2 The diffraction gratings will be inspected and tested to show compliance to the performance requirements stated in Section 3.2 4.3 A set of complete viewer acceptance tests will be con- ducted to demonstrate satisfactory operation of all the functions and specifications stated in Section 3.0. Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 This viewer will be packaged and prepared for shipment and delivered in accordance with accepted commercial practices. ? ? Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 -13- Approved For Release 2002/06/17 : CIA-RDP78BO4747AO01500020042-8 ?9 / STATINTL A?7TCK JUGFOPT F ,PACT Tar MAGN/F/CAT/ON AND 'Y'M7YfMFNJ CENJ COCAT/ON G7P/YE N)' , FOX Y'r190YEMENT ~ -tzarcv TO FNGASE CAN! FQC MA F N/F/ CAT i O N MO / f M E N T STATINTL