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DOT-SCREEN SHADOWGRAPH ILLUMINATOR CONCEPT

IP.com Disclosure Number: IPCOM000023942D
Original Publication Date: 1979-Apr-30
Included in the Prior Art Database: 2004-Apr-01
Document File: 2 page(s) / 387K

Publishing Venue

Xerox Disclosure Journal

Abstract

An illumination concept to permit dot-screenshadowgraph receptor with the simplest possible mechanical configuration. exposure of a photo- As shown in Figure 1, the illuminator consists of an integrating cavity 2 having an array of apertures 3. The cavity is coated inside with a diffuse, highly reflective material and is illuminated with one or more lamps 4. Each aperture is an ueffective!-source whose size is determined from the shadow profile considerations.

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XEROX DISCLOSURE JOURNAL

DOT~SCREENSHADOWGRAPH ILLUMI-~ NATOR CONCEPT
Ned Seachman

Proposed Classification
U.S. Cl. 355/67

mt Cl. G03b 27/54

An illumination concept to permit dot~screenshadowgraph exposurereceptor with the simplest possible mechanical configuration. of a photo~

As shown in Figure 1, the illuminator consists of an integrating cavity 2 having an array of apertures 3. The cavity is coated inside with a diffuse, highly reflective material and is illuminated with one or more lamps 4. Each aperture is an ueffective!~source whose size is determined from the shadow profile considerations.

2

F/G2 6

Volume 4 Number 2 March/April 1979 269

[This page contains 1 picture or other non-text object]

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DOT~SCREENSHADOWGRAPH ILLUMINATOR CONCEPT (Cont'd)

The location of the apertures is critical and is determined as shown. If is the normal distance from source to screen plane 5 and D

                                  2 the screen to photoreceptor plane 6 separation, then a source 11 will produce a screen pattern on the photoreceptor which is magnified by a factor of (l÷D

2/D1) over the pattern in the

screen aperture plane

            0 This magnification is easily shown to be constant across the entire field in both x and y directions. Because of this property, a second source 12 can be located at a new position (see Figure 2) such that its projected dot registers with one from source 11 but projected through a neighboring screen aperture. Because of the constancy of magnification, if one dot is properl...