US1387424A - Reflector - Google Patents

Description

M. M. MERRITT.

REFLECTOR.

APPLICATION FILED JULY 19,1917.

1,3 7,424 Patenwd Aug. 9,1921.

by nu-u UNITED STATES n r'rnnw x. unam'r'r, or mmvnas, mssacnusmrs, rnonuc'rs column, or nos'ron, nassacnu'sn'r'rs,

MINE.

I REFLECTOR.

Application filed July 19,

ToaZlwhomit-ma concern:

Be it known t at I MATTHEW M. Mme RITT, a citizen of the llnited States, and a resident of Danvers, county of Essex, Commonwealth of Massachusetts whose postoflice address is Danvers, Massachusetts, have invented an Im rovement in Reflectors, of which the following description, in con-' nection with the accompanying drawings, is a specification, like characters on. the drawin representing like parts.

his invention pertains to improvements in reflectors, and methods of making the same, and more particularly, though not exclusively, to improvements in reflectors peculiarly well adapted for use with highpowered nitrogen lamps. y

In lamps of this character, and to a lesser degree with other t es of high-powered; lamps, great difiiculty 'as been experienced because of rapid deterioration of the reflecting surface occasioned by heat, unequal expansion and other causes. K

Attempts have been made to overcome the difiiculty arising "from heat by electrolytically depositing copper on the back of the silvered surface of the reflector, but this has not been successful because of the deleterious action of the electrolyte on the silvered surface, because of unequal expansion of the glass or other transparent material on which the silvered surface is deposited, and of the copper backing which .causes imperfections in the si'lvered surface.

Among the objects of my invention is to provide a reflector in which, if desired, a glass parabolic lens may be silvered. and then coated with copper or other metal to conduct away the heat without impairment of the silvered surface, while reven'tingdeterioration of the silvered sur ace occasioned by unequal expansion of the copper and glass or by the electrolyte.

In the drawings I haveshowna p Figure 1 a section, 1pgrtiall in elevation, of an illustrative para lic reflectormade in accordance with one embodiment of my invention; v I

Fig. 2 is an enlarged section through a portion of the parabolic reflector shown in i 1. a fieferring to the drawings of the preferred form of my invention selected for illustrative purposes, I have shown a parabolic respecmcatlon of Letters Patent. Patented Aug. 9, 1921.

1917. Serial No. 181,836.

or spread on the back surface of the silver,

and may be composed of a hite and linseedpil. In the preferred fo i'm of my invention, after this coating has hardened ,1 preferably rovide a second coating, which may take t e form of a layer of paint 3, preferably water-proof and acid-proof, but preferably carryin a conducting load such as a metallic pow er. I preferably incorporate this powder in the paint prior to its applicatlon, but for some purposes I may applythe conductive material direct to the surface -of the first coating or to the surface of a. suitable vehicle spread over the surface of the preliminary coating. The second coating preferably comprises powdered brass mixed with amyl-acetate.

After the second coating has thoroughly dried, I preferably immerse the reflector in an electrolytic bath, either still or agitated, and deposit metal 4 thereon until the desired thickness is obtained. The malleablecoating and the conductive coating are both referably continued around the edge 0 the front of the lens so that the rim is protected and thefirm adherence of the backing to the glass is insured in spite of vibration to which it ma be subjected when used in motor cars and t elike.

.I have found in practice that the copper very readily absorbs and very readily gives off the heat of the lens, so that the si-lvering is not raised to .such a temperature as woul blister or otherwise injure it. I have also found that the coating interposed between the silver and the copper permits suflicient go and come without injuryto the silver to eliminate that deterioration of the silver which would normally arise from the unequal expansion of the glass and copper if the intermediate protective coatings were not utilized.

55 flector comprising a glass or other transpar- It will be understood that while throughout the specification and claims I have referred to glass as the transparent material forming the front of the reflector, and to silvering or silver as the reflective element, I have used glass generically to include any transparent protective coating or material for the silvering, and that I have used sllver or silvering genericallyto include any type of reflecting material.

While I have illustrated and described a preferred embodiment of my invention and a preferred method of practising, the same, I wish it understood that my invention is not limited to the structure or methods illustrate-d and described, and may be greatly varied within the scope of the appended claims.

Claims:

1. A reflector, comprising in combination,

a glass, silvering on said glass, a coating of graphite and linseed oil back of said silvering, a coating of relatively high conductive 1113136131211 back of said coating of graphite and linseed oil, and a sheet of electrolytically deposited metal back of said relatively high conductive coating. I

i 2. A reflector comprising, in combination deposited metal on theback of said coating t of owdered metal and amyl-acetate.

n testimony whereof, I have signed my 35 name to this specification. I

"- MATTHEW M. MERRITT.

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