US804254A - Prismatic-glass reflector-shade. - Google Patents

Description

' No. 804,254 7 PATENTED NOV. 14, 1905. 0. A. MYGAIfI.

PRISMATIS GLASS REFLECTOR SHADE.

APPLIGATION FILED 311F113. 1904.

Z SHEETS-SHEET 1.

No. 804,254. v PATENTED NOV. 14, 1905.

- 0. A. MYGATT.

PRISMATIG GLASS REFLECTOR SHADE.

APPLICATION FILED 111333, 1904.

2 8KEETBSHBET 2.

'PIGJIQ WITNESSES.-

61. if M.

m W Y aw UNITED STA ES Specification of Letters Patent.

PATENT OFFICE.

PERM

PatontedN 14, 1905.

Application filed Juno 3, 1904- Serial No. 210.978.

To all whom it may concern: 1

Be it known thatl, One A. Mrea'rr, acitizen of the United States,residingat New York, in the county of NewYo'rk'aud State of New York, have invented certain new and useful Improvements in Prismatic-Glass Reflector Shades. of which the following is a specification.

This-invention relates to improvements in glass reflector-shades for artificial lights.

The ob ect of the invention is to pruduce in one unitary structure a reflector and shade composed entirely of glass and having a part acting entirely as a reflector and an opposite part acting as a light directing or distributing and softening shade. i

The invention consists. in a structure hav ing a part. usually about one-half its surface, covered entirelywith reflecting-prisms, constructed to direct back into the shade a large.

portion of the light-rays which emanate within the reflector. The other sideof the reflector-shade is substantially a shade. It has on its outer surface aseries of light directingor distributing prisms or ribs, which prisms direct the light in any desirable direction and at the same time soften the light-rays. On this directing side the interior surface of the shade may be covered with diffusing-ribs.

which soften the light-rays before they reach the final directing-prisms.

Figure 1 is a side elevation of a shade-refiector embodying the principles of the pres- 'a modified form of shade-reflector intended specially for incandescent electric lights. Fig. 7 is a side elevation of a further modification. Fig. 8 is a rear elevation of Fig. 7; Fig. 9, a broken section on line 2 z.

My shade-reflectors are made of pressed glass and in all common sizes are in a single piece. That side A of the body of the structure which is to act entirely as a reflector is substantially covered by external prisms B. These prisms are of the character termed by me double-reflecting prismsthat is. the light from within the reflector encounters a smooth interior surface K and is deflected very little or not at all thereby. Passing to the outer inclined face of a prism B a lightray encounters this face at an angle of fortyfive degrees, (for best results.) The ray is.- reflected at a right angle directly across the 6o prism and strikes the second inclined facealsc.

at an angle of forty-five degrees thereto, (see Fig. 4.) wherein 1 Zindicatesa light-ray thus reflect-ed twice. The light-ray is thus returned on a line substantially parallel with its line of radiation. This direction of a light-ray may be somewhat modified by the form of the body, as at 3 4, Fig. 2. For ordinary consideration it may be calculated that from seventy to eighty per cent. of the light will 0 bethrown back toward and through a lamp inclosed in the reflector and toward theshade or light distributing or radiating side of the device. i

The. shade-reflectors are shown in vertical 7 5 position in Figs. 1 and 6, but can beturned to any position desired- For convenience of description the prisms will be described in. the positions they occupy when the reflectorshades are in the'position of Figs. 1 and 6.80 Thus it will be seen that the prisms B extend in generally vertical direction with reference to the body of the shade-reflector. In a spherical reflector the reflecting-prisms are substantially in the form of lanes. Some light 8; will pass through the prismatic reflector, and the external appearance of a lighted reflector will be that of a darkened surface with bright lines thereof. To maintain the proper reflective angles of their plane surfaces. the reflecto ing-prisms must vary in width and height with their position on the body'of the reflector.

The front or light-diffusing side C of the. shadereflector is preferably covered internally with small vertical or lunar prisms or ribs D. These internal prisms will not reflect the light back toward its source, but will simply deflect the light-rays more or. less in horizontal direction as they pass through the glass. The surfaces need not be planes. but may be we merely. rounded flutings for this purpose. The amount of light received by the front face G or shade part of the device'will be something less than twice the amount which would be there received were the reflector 5 part of the device omitted. 1

The outer surface of the shade C is substantially covered with horizontal directing or distributing prisms E. These prisms are of various characters. according to the illumination desired. These prisms may be singlereflecting prisms or light-directing prisms and 'QQ UED I ill height of the shade--may be made to directthe light-rays in a direction inclined downwardiy at a considerable angle. The prism along the central part of the face C may be made to direct the rays downwardly at a lesser angle, g

and the prisms at the lower part of the face 1 C may he made to direct the rays about-horij zontally. Such directions for light-rays are indicated by lines 5 6, 7 8, 9 10, Fig. 3. Such an arrangement for prisms will give a K its outer rear face substantially covered with concentration of light along a horizontal band Other arrangement or near theshade-face. construction of the prisms E may be made to concentrate the rays or to diffuse them, as

desired. The directing-planes of these prisms 'are determined by the mold, which is made oncarefully-calculated lines.

By continuing the reflector side of. the device for something more than half the circumferencc a very considerable concentration of light-rays may be effected over a limited area at the front of the reflector-shade.

' In the patent of Blondc-l rt 01., No. 563,836, July 14, 1896, the construction of horizontal light-directing prisms is explained atlength. In my Patent No. 4 6,535, of August 18, 1903, the construction of vertical reflecting-prisms on the outer face of me reflector is explained. These latter prisms I term double-reflecting prisms, while thehorizontal prisms E, if reflectors at all, are single-reflecting or lightdistributing prisms and m" serve merely to I diffuse the light-rays.

By lightalistribnting" prisms I refer to prisms having their plane faces at calculated angles with reference to the source of light, so that a large proportion of light passing thrmigh the prisms collectively shall he by the prisms directed in definite quantities in predetermn ti directions. By light-diffusing I mean thrlnralzi: up of the light-rays and the srat 'rn'ig ard olmning of the rays without attempt in i't llLlUl the quantity of light in a'given direction.

As shown in Figs. 7 and 8, the reflector may have lunar reflecting-prisms rar'liating from one center instead of from two centers, as in Fig. 6.

Light-distribution, as understood in this art, is the direction of light-rays in definite and isa reflector and the lower part is surrounded.

by circumferential prisms, which may he directing-prisms. If this globe were turned at a right-angle, it would have the effect of directing the light. in rings or circles instead of the distribution of the light-rays in a plane or planes, as in the present invention.

'hat I claim is 1. A'prismatic-glass reflector-shale having integral reflecting-prisms arranged to reflect light-rays back into the shade and out at the front thereof, and having lts front outer face substantially covered with prisms, with their longer axes extending in agenerally horizontel-direction, and arranged to pass the lightrays in predetermined directions according to the inclination of the plane faces of'said prisms.

2. A prismatic-glans reflector having its outer rear face suhstantlall y covered with inte-gral reflect1ng-pr1sms, and its inner surface opposite said reflecting-prisms smooth. and

having on its front outer surface a series of horizontally arranged light-directing prisms.

3. A prismatic-glass reflector having its outer rear face substantially covered with reflecting-prisms extending in a generally vertical direction and its inner rear s u rface smooth,

and having its front outer surface substantially covered with light-directing prisms with their longer axes arranged horizontally. and the interior surface behind these directingprisms covered with diffusing-ribs.

4. An integral reflector-shade to inclosc an artificial light. composed of glass, with its rear face externally covered with prisms arranged to reflect a large proportion of the light-rays from w thin, back into the device and out through the opposite face. the shade or distributing side of the device being provided with prisms with their longer axes extending in a generally horizontal direction, and havin; their plane faces arranged 'to direct the passing light-rays in converging p anes.

In testimony whereof I affix my signature in presence of two witnesses.

UTIS A. MYGATT.

'itncsses:

H. E. Nasox,

Geo. A. Cora.

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