US3725694A

US3725694A - Portable lamp for viewing fluorescent material

Info

Publication number: US3725694A
Application number: US00131105A
Authority: US
Inventors: O Lednicer; Amato S D; C Guertin
Original assignee: American Bank Note Co
Current assignee: BNY Mellon NA
Priority date: 1971-04-05
Filing date: 1971-04-05
Publication date: 1973-04-03
Anticipated expiration: 1990-04-03

Abstract

Portable lamp, such as a flashlight, for viewing printed material having fluorescent, normally invisible markings thereon, comprising a flashlight having an ultraviolet lamp, and an opaque hood around the lamp and projecting beyond the lamp. The end of the hood is opened and is adapted to be placed against a printed document to be viewed. An aperture is provided in the side of the hood through which the document may be viewed while it is held against the end of the hood.

Description

United States Patent 1 1 3,725,694 DAmato et al. [4 1 Apr. 3, 1973 PORTABLE LAMP FOR VIEWING Primary Examiner-Donald O. Woodiel FLUORESCENT MATERIAL Inventors: Salvatore F. DAmato, Flora Park, N.Y.; Clifford D. Guertin, River Vale; Oliver Lednicer, Hackensack, both of N].

American Bank Note Company, New York, NY.

Filed: Apr. 5, 1971 Appl. No.: 131,105

Assignee:

us. Cl. .......240/6.4 R

Int. Cl ..F2lv 33/00 Field of Search ..240/6.4 R, 6.4 B

References Cited UNITED STATES PATENTS Quam ..240/6.4 R

Attorney-Lester W. Clark et al.

[57] ABSTRACT Portable lamp, such as a flashlight, for viewing printed material having fluorescent, normally invisible markings thereon, comprising a flashlight having an ultraviolet lamp, and an opaque hood around the lamp and projecting beyond the lamp. The end of the hood is opened and is adapted to be placed against a printed document to be viewed. An aperture is provided in the side of the hood through which the document may be viewed while it is held against the end of the hood.

3 Claims, 3 Drawing Figures PORTABLE LAMP FOR VIEWING FLUORESCENT MATERIAL BRIEF SUMMARY OF THE INVENTION The novel feature of this invention is a hood, comprising an elongated hollow member having one end adapted for attachment to the casing of an ultraviolet lamp, such as a flashlight. The other end of the hood is open and is adapted to be placed against a document to be viewed. An aperture is provided in the side of the hood, near the open end, through which the document may be viewed while it is held in place over the open end of the hood. The hood shields the document from illumination by sources other than the ultraviolet lamp,

which illumination might otherwise mask the fluorescense.

THE DRAWINGS FIG. 1 is an elevational view of a portable lamp embodying the invention.

FIG. 2 is a plan view of the lamp of FIG. 1, partly in section, on an enlarged scale.

FIG. 3 is a cross-sectional view taken on line 3-3 of FIG. 2.

DETAILED DESCRIPTION An ultraviolet flash lamp 1 includes a casing 2, enclosing batteries 3. Switch means 4 and 5 are mounted on the casing. One end of the casing supports an ultraviolet lamp 6, and the other end of the casing is closed by a suitable cap which holds the batteries in place. The switch means 5 includes a pushbutton 5a for turning on the lamp momentarily and a slide switch 5b for holding the lamp on for a longer period of time. The circuits controlled by the switch 5 energize the filament of the lamp 6. An ultraviolet radiation producing discharge, such as a mercury vapor discharge, takes place in the lamp 6 after the switch 4 is closed to complete a starter circuit. The structure as thus far described is conventional.

Mounted on the lamp and the casing 2 is a hood 10 having formed at its upper end, as viewed in FIG. 2, internal threads 100 which are adapted to engage external threads 11 on the end of the casing 2. The opposite or lower end of the casing 10 is open, as shown at 10b, and is adapted to be placed against a document 12 to be viewed. The document 12 may be held against the open end 10b manually, or it may be placed on a flat surface and the end of the hood 10b placed against it. The hood 10 is provided with a side aperture 100 through which the document 12 may be viewed when the ultra-violet lamp 6 is energized and the document 12 is held in place against the end. The hood l0 shields the document from sources other than those aligned with the aperture 100, which might otherwise mask any fluorescense appearing on the document 12.

A window 13 is held in place against a flange 10d formed on the inside of the hood 10, by means of a split ring clamp 14.

fluorescent pigments whichare normally invisible, but which can be seen when the document is placed in a darkened area and illuminated with ultraviolet light. Referring to FIG. 3, the characters C, D, E, F, shown in full lines, are visible through aperture 10c while the characters A, B and C, which are outside the hood 10 and are illuminated by external light, are shown in dotted lines to indicate that they cannot be observed by a human eye.

The characters in question may be printed across areas of the documents intended to be written on or to have a value imprinted thereon. Then, if an attempt is made to change the value or change the original writing, the original fluorescent characters are destroyed by the necessary erasure. Such an erasure can be detected by the use of the portable lamp illustrated. A counterfeit document, where the fluorescent characters are completely missing, can also be readily detected.

In using the lamp, the aperture 10c should be directed away from any external light source, in order to minimize the visible light falling on that part of the document within the hood 10.

We claim:

1 A portable lamp for viewing fluorescent printe material, including:

a. a casing;

b. an ultraviolet lamp supported on the casing;

c. electric circuit means for energizing the lamp including switch means mounted on the casing; wherein the improvement comprises:

d. an opaque hood mounted on the casing and encir cling the lamp and projecting beyond the lamp and open at its end remote from the casing, said open end being adapted to be placed against a document to be viewed, said hood having an aperture in one side thereof through which a document may be viewed while it is in contact with the open end, said hood being effective to shield the portion of the hood against illumination from external sources other than those aligned with the aperture.

2. A portable lamp as defined in claim 1, including retaining means inside the hood between the side aperture and the lamp, and a window supported on said retaining means.

3. A hood adapted for attachment to an ultraviolet lamp to adapt it for viewing printed material, including an elongated hollow, opaque member having means at one end for attachment of the casing of the ultraviolet lamp, said member being open at the other end, and having a side aperture adjacent said other end through which a document placed in contact with the open end may be viewed, while it is shielded by the hood from light from external sources other than those aligned with the aperture.

Claims

1. A portable lamp for viewing fluorescent printed material, including: a. a casing; b. an ultraviolet lamp supported on the casing; c. electric circuit means for energizing the lamp including switch means mounted on the casing; wherein the improvement comprises: d. an opaque hood mounted on the casing and encircling the lamp and projecting beyond the lamp and open at its end remote from the casing, said open end being adapted to be placed against a document to be viewed, said hood having an aperture in one side thereof through which a document may be viewed while it is in contact with the open end, said hood being effective to shield the portion of the hood against illumination from external sources other than those aligned with the aperture.