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Publication numberUS586248 A
Publication typeGrant
Publication dateJul 13, 1897
Filing dateFeb 12, 1897
Publication numberUS 586248 A, US 586248A, US-A-586248, US586248 A, US586248A
InventorsFrank C. Soper
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
US 586248 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

(No Model.)

P. 0. ER.


No. 586,248. Patented July 13, 1897,.




rSPECIFlCATIQN forming part of Letters Patent No. 586,248, dated July 13, 1897.

Application filed February 12, 1897. Serial No. 628,539. (No model.)

1.0 aZZ whom it may concern.-

Be it known that I, FRANK C. SOPER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois,

have invented certain new and useful Improvements in Vault-Lights, of which the following is a specification.

My invention relates to devices for distributing light, and has for its object to provide a new and improved device for this purpose.

My invention is illustrated in the accompanyin g drawings, wherein- I Figure 1 is a side view of a vault-light embodying my invention. Fig. 2 is a plan view of the same. Fig. 3 is a section on line 3 3, Fig. 1.

Like letters refer to like parts throughout the several figures.

It has been the custom heretofore in C011 2o structing vaultdights and the like to consider simply the rays of light which fall substantially perpendicularly upon the receivingsurface.

The objectof my invention is to provide a vault or other light or similar device so constructed as to utilize the rays of light which strike the receiving-surface at an angle, such rays being lost when the ordinary vault-light is used.

I have illustrated in the drawings a vaultlight provided with a body portion A, having a receiving-surface A and having the pro- 3' ectin g parts or prisms B. I have constructed this vault-light so as to embody my invention, and although I have shown a peculiar kind of vault-light to illustrate my invention it is of course evident that I may use my invention in connection with any light-dilfus ing device to which it can be applied. Each 40 of the projecting prisms B is provided with the reflecting-surface l3 and the refractingsurface 13 and is Jrovided wit-h the inclined edges C, the prisms shown being made so that they are wider at the bottom than at the top. I have shown these edges in the drawings as broken up into a series of ribs having substantially parallel surfaces; but I do not wish to be understood as limiting myself in any particular to this construction, as these faces or edges may simply consist of an inclined surface or they may be of any other suitable shape or form, the only condition being that they will reflect the oblique rays of light; neither do I limit myself to the embodiment of my invention in a vault-light, as it may be used in connection with other lightdiffusing devices.

I have indicated in Figs. 2 and 3 some of the rays of light which strike the receivingsurfaces at an angle and which are then reflected and refracted by the prisms, so as to be projected toward the point where the light is desired.

The use and operation of my invention are as follows:

hen the rays of light that strike the receiving-surface of the vault-light are substantially perpendicular to such surface, they are reflected by the reflecting-surface and refracted in the ordinary manner. lVhen the oblique rays of light E, for example, strike the receiving-surface of the vault-light, they are refracted and then strike the surface C and are then reflected, the line of direction being changed so that they will strike the reflecting-surface B in a more nearly vertical direct-ion. The rays of light are then reflected and pass out through the refractingsurface B and are hence directed toward the point where the light is to be utilized. In the vault-1i ght as ordinarily constructed these rays of light pass through the surface G or are reflected in a direction not desired and are thereby lost. hen my construction is used, these rays instead of being lost are proj ected toward the point where the light is desired, and a much better illumination is obtained.

The inclination of the edges of the prism 13 is intended, first, to receive the light and refleet it downwardly, as indicated in the drawings, and, in the second place, when these edge surfaces are themselves prismed or ribbed to permit the light reflected from the upperprisin surface to pass downwardly without striking the next prism, which would occur if such prisms were arranged on a vertical surface, and, in the third place, the reason for these side edges is to give a larger area at the bottom to reflect the light, an area approximately equal to the exterior surface length. These ribs or prisms on the edges of the principal prism I have called the secondary prisms.

I have spoken of my device as a vaultlight. By this term I mean a prism-tile, and this latter is the term which I prefer to use.

I claim 1. A prism-tile eonsisiingof a body of trans parent material having on one side a receiving-surface and on the other side a prism provided with front and rear principal refracting and reflecting surfaces, and with edges which converge toward the receivingsurfaee which are substantially flat and lie in planes substantially parallel with the direction in which the light treated by the principal surfaces is projected, and secondary prisms on such edges.

A prism-tile consisting of a body or transparent material having on one side a receiving-surface and on the other a prism provided with front and rear principal refracting and reflecting surfaces and edges which are provided with secondary prisms and lie in planes substantially parallel with the direetion in which the light treated by the principal surfaces is projected.




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US2546335 *Mar 28, 1949Mar 27, 1951Friend James RIllumination louver
US2899861 *Oct 15, 1954Aug 18, 1959 Follower magnifier for planimeters or similar instruments
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US6447135Oct 8, 1999Sep 10, 20023M Innovative Properties CompanyLightguide having a directly secured reflector and method of making the same
US6560026Jan 16, 2002May 6, 2003Mark E. GardinerOptical film with variable angle prisms
US6707611Jan 29, 2003Mar 16, 20043M Innovative Properties CompanyOptical film with variable angle prisms
US6845212Oct 8, 1999Jan 18, 20053M Innovative Properties CompanyOptical element having programmed optical structures
US7046905Jul 11, 2000May 16, 20063M Innovative Properties CompanyBlacklight with structured surfaces
US7221847Aug 3, 2004May 22, 20073M Innovative Properties CompanyOptical elements having programmed optical structures
US7873256Sep 14, 2005Jan 18, 20113M Innovative Properties CompanyBacklight with structured surfaces
US8588574Oct 30, 2007Nov 19, 20133M Innovative Properties CompanyBacklight with structured surfaces
Cooperative ClassificationF21S11/00