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PLASTIC ATTENUATORS FOR LAMP ADJUSTMENT AND AXIAL PROFILE SHAPING

IP.com Disclosure Number: IPCOM000025013D
Original Publication Date: 1983-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 70K

Publishing Venue

Xerox Disclosure Journal

Abstract

Figure 1 illustrates, in end view, a portion of an optical illumination system in which a document 10 lying on a platen 12 is illuminated by a lamp assembly 14. Assembly 14 comprises an apertured fluorescent lamp 14 having an attenuator element 18 positioned over lamp aperture 20. The purpose of element 18 is to compensate for axial intensity variation of lamp 14. Examples of possible alternative patterns are shown in Figures 2a, 2b. Here, element 18 is formed as a clear plastic strip 20 with a dot screen pattern (Figure 2a) or a line screen pattern (Figure 2b) formed on the surface. The dots or lines are spaced further apart at

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EROX DISCLOSURE JOURNAL

PLASTIC ATTENUATORS FOR LAMP ProDosed Classification ADJUSTMENT AND AXIAL PROFILE
SHAPING
James J. Appel

U.S: C1. 355/8 Int. Cl. G03g 15/28

10

f 1

............... ...............

* ...............

l8 ? FIG. 20

c)

B

Figure 1 illustrates, in end view, a portion of an optical illumination system in which a document 10 lying on a platen 12 is illuminated by a lamp assembly 14. Assembly 14 comprises an apertured fluorescent lamp 14 having an attenuator element 18 positioned over lamp aperture 20. The purpose of element 18 is to compensate for axial intensity variation of lamp 14. Examples of possible alternative patterns are shown in Figures 2a, 2b. Here, element 18 is formed as a clear plastic strip 20 with a dot screen pattern (Figure 2a) or a line screen pattern (Figure 2b) formed on the surface. The dots or lines are spaced further apart at

Volume 8 Number 2 March/April 1983 147

FIG a

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PLASTIC ATTENUATORS FOR LAMP ADJUSTMENT AND AXIAL PROFILE SHAPING (Cont'd)

the strip ends permitting a greater amount of light to emerge so as to compensate for the fall-off in illumination at the lamp ends. The substrate material for strip 20 can be, for example, polyester or polycarbonate. The dot or line pattern can be applied by silk screening or offset lithography.

As the lamp 11 ages, the total amount of light decreases and it may be desirable to form several strips, each with a differen...