US3586897A

US3586897A - Electric lamps with light transmitting yarn strands for decorative purposes

Info

Publication number: US3586897A
Application number: US747775A
Authority: US
Inventors: Norman Baird
Original assignee: Duro Test Corp
Current assignee: Duro Test Corp
Priority date: 1968-07-17
Filing date: 1968-07-17
Publication date: 1971-06-22
Anticipated expiration: 1988-06-22

Abstract

Electric lamps having a plurality of strands of a light transmitting yarn adhered thereto to produce a decorative effect. The adhesive used to adhere the strands to the lamp envelope, the strands themselves, and/or another coating of material can be colored or pigmented to further enhance the decorative effect.

Description

United States Patent [72] Inventor Norman Baird [56] References Cited lngngsllams, NJ. UNITED STATES PATENTS $5 M 968 389,526 9/1888 Moore 313/116 Patented 197 2,850,421 9/1958 Thompson 117/126 ER [73] Assi nee Co "60 2,946,911 7/1960 Malinowski et a1 117/18 g Norm Ber m, 2,963,612 12/1960 Thorington 313/116 8 3,127,295 3/1964 Throingtonm. 117/94 3,146,499 9/1964 Keppler et a1. 1 17/26 Primary ExaminerWil1iam D. Martin Assistant Examiner-Rayrnond M. Speer 541 ELECTRIC LAMPS WITH LIGHT TRANSMITTING mm-Darby Daby YARN STRANDS FOR DECORATIVE PURPOSES Claims 5 Drawmg Figs ABSTRACT: Electric lamps having a plurality of strands of a [52] U.S.Cl 313/116, light transmitting am adhered thereto to produce a decora- Y 117/18. 117/26, 117/33 tive effect The adhesive used to adhere the strands to the [51] Int. Cl H0lj 61/40 lamp envelope, the strands themselves, and/or another coating [50] Field of Search 117/ 18, 26, of material can be colored or pigmented to further enhance the decorative effect.

PATENTED JUH22 I971 FIG .11

FIG. 3

FIG.

INVENTOR NORMAN BAIRD 4 m; A? BY ATTORNEYS IELIECTll-IIC LAMPS WITH LIGHT TRANSMITTING YARN STRANDS FOR DECORATIVE PURPOSES This invention relates to electric lamps and more particularly to an electric lamp having strands of light transmitting yarn applied thereto for imparting a decorative effect.

Several types of light modifying coatings have been used on electric lamps to produce a decorative effect. In general, the light modifying coatings employed for decorative effects may be smooth or rough in their surface character and may selectively transmit or reflect certain wavelengths in the visible spectrum to render unique and pleasing decorative effects. One type of lamp with a light modifying coating is shown in US. Pat. No. 2,963,6l2 issued Dec. 6, 1960, which is owned by the Assignee of the subject application. In that patent a lamp is disclosed in which a yarn of light transmitting material is wound around the outside of the lamp envelope in a predetermined pattern and adhered thereto. The yarn, in addition to producing a decorative optical effect, also serves to strengthen the envelope and make it more shatterproof.

The present invention relates to a lamp having a light modi' fying coating thereon which is decorative both in the lighted and unlighted states. In accordance with the invention a coating is used which comprises a plurality of small pieces, or strands, of a light transmitting yarn of predetermined or random lengths arranged in a random pattern over part or all of the lamp envelope. The strands are held to the lamp envelope by a suitable adhesive coating making them an intimate part of the adhesive binder system. This serves to strengthen the glass envelope from breakage due to impact or thermal shock. In a preferred embodiment of the invention the strands and adhesive are also overcoated with a protective film or coating.

in the present invention the adhesive material can be tinted or pigmented with color to serve as a color filter to enhance the color light output of the lamp. The strands themselves also can be tinted or pigmented. Further, the overcoating for the strands and adhesive material also can be tinted or colored. All of these enhance the decorative effect of the lamp.

In a preferred embodiment of the invention, pieces of fiber glass are used for the strands. When the strands of the decorative medium are glass and the coatings used are of an inorganic nature, the heat resistance, that is the resistance to breakage due to thermal shock, of the decorative lamp is increased. This gives rise to wider use of the lamps in outdoor receptacles in higher wattage ratings. Also, the lamps have greater resistance to shattering due to mechanical shock. Both of these features provide greater versatility than available with prior art lamps.

It is therefore an object of the present invention to provide a decorative lamp using strands of light transmitting material.

A further object is to provide a decorative lamp using glass fiber strands which are held to the lamp envelope by a system comprising an adhesive and a suitable coating material over the strands and the adhesive.

Another object is to provide a decorative lamp using strands of light transmitting material held to the lamp envelope by a material which also serves as a color filter.

A further object is to provide a decorative lamp using strands of light transmitting material which are adhered to the lamp envelope in which the strands serve as a color filter.

An additional object is to provide a novel decorative lamp formed with strands of a light transmitting material which are held to the envelope by an adhesive material and an overcoat is provided which serves as a color filter.

Other objects and advantages of the present invention will become more apparent upon reference to the following specification and annexed drawings, in which:

FIG. 1 is an elevational view of the lamp of the present invention;

FIG. 2 is an elevational view partially broken away;

FIG. 3 is a fragmentary sectional view of the lamp shown in enlarged scale;

FIG. l is a perspective view of a strand of light transmitting material utilized in the present invention; and

FIG. 5 is a fragmentary sectional view of another embodiment of the lamp.

Referring to FIGS. 1 and 2, an incandescent lamp 1 is shown which has a generally spherical glass envelope 6. While the invention is described with respect to an incandescent lamp, it should be understood that it also may be applied to other types of lamps and envelopes of shapes other than the spherical shape shown. A screw-type base 5 is connected to the bottom of the envelope 6 by a suitable adhesive. The base holds the usual reentrant'stem 7 with support wires 8. These wires 8 in turn hold the incandescent filament 9. A pair of lead wires 10 are electrically connected to the ends of the filaments 9 and to the terminals provided by the base 5. As is conventional in lamp manufacture, there may either be a vacuum or a specific gaseous atmosphere within the envelope 6.

In accordance with the invention, the novel decorative lamp is obtained by affixing a large number of strands 2 of a light transmitting yarn in a random pattern to the envelope 6 by an adhesive coating material 3. The strands 2 are aligned by physical means to make contact along their lengths with the adhesive coating 3. This can be accomplished by brushing the strands onto the adhesive coating after it has been applied to the glass envelope and/or by rolling the envelope.

The strands 2 which are affixed to the envelope are of any suitable light transmitting material, such as glass or quartz fiber. Suitable plastic materials such as NYLON and DACRON also can be used. The strands can also be monofilament or multifilament. In the latter case they can be braided or twisted together, or else just lie in a generally parallel relationship. Thus, each strand contains a number of individual filaments or fibers.

In a preferred embodiment of the invention, multifilament fiber glass yarn is used. In one preferred type of yarn shown in FIG. 4, a number of filaments lie in a side-by-side relationship held together by the adhesive or sizing material used during processing. The multifilament yarn is chopped or cut to any desired strand length, or lengths. Also, the widths of the strands can be varied by breaking off some of the filaments.

When glass fiber strands are used, they are preferably sized and surface-treated, as is common to the art, for their protection and adherence with the resins in which they are ultimately used. Various strand lengths can be employed so that the same lamp can have strands all of the same size, of different predetermined quantities of predetermined sizes, or of random sizes. Where glass fiber strands have been used, lengths of one-eighth inch-three-fourths inch have been found to be satisfactory depending upon the curvature of the lamp bulb surface or the particular decorative effect desired. The width (or diameter if more circular yarn is being used) of the strands also can vary as desired by using yarn with filaments of different diameters and/or different numbers of filaments. Where fiber glass is used, preferred and suitable widths can range from one-thousandth to one-sixteenth of an inch. It should also be understood that the present invention contemplates the use of strands of all the same length and width on the same lamp and of different and/or random widths and lengths.

The adhesive material 3 for holding the strands 2 on the envelope 6 may be of any suitable type. Preferably, the adhesive coating 3 is a material which by nature of its solvent or resin content remains tacky for a period of time, or indefinitely, and which has suitable stability in elevated temperatures. This permits a suitable amount of processing time to place the strands on the envelope. The nature of the adhesive coating 3 also depends upon the wattage rating of the lamp and whether the lamp is of the gas filled or vacuum type. Additionally, the suitability of the coating 3 to colorants must be considered. In the form of the invention shown in FIG. 2, where fiber glass strands are utilized, a clear, colorless, heat resistant, pressure sensitive, silicon adhesive is used. This coating remains permanently tacky and therefore lends more versatility to process conditions. One suitable adhesive which can be used with fiber glass has been found to be the following:

Weight percent Dow Corning 281 adhesive 26. 2 Toluene a A 3R. 6

Acetone c 2 Other suitable adhesives are described in the aforesaid US. Pat. No. 2,963,6l2.

The thickness of the adhesive coating depends upon numerous factors such as the application technique, that is whether the coating is brushed, sprayed, or dipped, adhesive viscosity, bulb temperature and adhesive temperature. A l3 mil layer has been found to be satisfactory for fiber glass strands.

In accordance with the operation of the lamp of FIGS. 1 and 2, light produced by the filament 9 passes through the adhesive coating 3 to the strands 2. The light is refracted by the individual strands and also reflected. This gives a pleasing, decorative, appearance.

As indicated above, each strand of fiber glass is formed of a number of fibers or filaments. To prevent loosening of the filaments of the strands, a second coating, or overcoat 4, is deposited over them after they are adhered to the envelope. This is shown in FIG. 3. The overcoat 4 is preferably used whether or not the strands are of the multifilament yarn type since, as described below, it enhances the decorative effectof the lamp.

The overcoat layer 4 can be any lacquer system which is compatible with the adhesive coating 3 to obtain ultimate clarity of the areas between strand pieces. The solvent system of the lacquer should not have a low surface tension which would enable penetration and coating of the glass fibers within the strands by the resins dissolved in the lacquer system. The viscosity of the lacquer and the method used in its application must provide a thickness of coating which after cure, provides adequate protective coverage of the strand pieces. The embodiment illustrated in FIG. 3 uses, for example, an overcoat layer 4 comprising a heat resistant, transparent, catalyzed silicone lacquer which possesses the characteristics referred to above. This material dries to a hard finish. The overcoat is applied by any suitable technique, for example, spraying, dipping, painting, etc. One suitable overcoat material has been found to be:

Vcight percent Dow Corning A-40flfl Adhesive 63. R

Xvlcne t 17. 9

Toluene t 1S. 3 Dow Corning A-4000 catalvst solution-5.3

parts per 100 parts adhesive.

In the operation of a lamp using the overcoat 4 of FIG. 3, a portion of the light emitted by the incandescent filament passes through the glass envelope 6, the adhesive coating 3 and the protective overcoat 4 without encountering any of the strands 2. The overcoat 4 can also serve, if desired, as a color filter. This is described in greater detail below.

Some of the light emitted from the filament passes through the adhesive coating 3 and through the thickness of one or more strands 2. In passing through the strands, the light is reflected from the individual fibers forming the strand, where a multifilament yarn strand is used. This light eventually passes through all the individual fibers forming a strand and through the protective overcoat 4. Other portions of the emitted light are reflected by the outer portions of the strands. The overall effect is one of distinctly different degrees of surface brightness between the strand pieces and the areas between them. A glittering of light is evident and an effect similar to cracked glass is produced.

In addition to the decorative effect produced by light emitted from the filament, another decorative effect is produced by incident light. Considering, for example, the overcoat structure of FIG. 3, a portion of the incident light is reflected from the strands and the individual fibers therein. Another portion of the incident light is transmitted through the adhesive coating 3 and the protective coating 4. A differential of reflectivity and transmittance exists which provides a glitter effect similar to that obtained when the lamp is operating and the light is produced by the filament 9. The degree of glitter depends upon the intensity of the incident light. The present invention therefore produces a lamp which possesses a novel and attractive glitter, or cracked glass, effect in either the energized or nonenergized state.

As indicated above, the lamp of the present invention can be made color selective to further enhance its decorative effect. For example, the adhesive coating 3 can be modified by incorporating a suitable pigment or dye to provide selective filtration of the visible spectrum emitted by the energized filament as well as incident light. When this is done the lamp has a color, which is selected to be an attractive one, in the nonenergized state. The colored adhesive also enhances the presence of the strand pieces when the lamp is in the nonener gized state.

When the colored adhesive is used, incident light in all wavelengths passes through the clear overcoat 4 and is reflected by the strand pieces 2. Areas between the strands 2 having the colored adhesive reflect back the wavelengths effected by the colored part. A small portion of the light not reflected but transmitted by the strands is reflected back into and through the strand pieces by the colored adhesive layer 3 beneath them. However, the intensity of this reflected light is low compared to the colored light reflected from between the strand pieces and the contrast is effective. The protective overcoat 4 of this arrangement is applied in the same manner previously described and is clear.

FIG. 5 shows another embodiment of lamp wherein the color filtration is obtained in a different manner. Here, the adhesive 3, strands 2 and overcoat 4 are clear, that is uncolorcd. A transparent lacquer is provided with a suitable dye to produce a transparent colored film for the overcoat 4. The separate lacquer coating, designated as a colored film 15, is applied and cured over the overcoat 4. The selective filtration of the colored film 15 in this embodiment provides a different effect from that in which the filtration was produced by the adhesive coating 3. Here, light emitted from the incandescent filament as well as incident light are selectively filtered in the visible range by the film 15. Thus, strands 2 reflect and transmit light of the same color as transmitted by the areas offilm 15 between them on the bulb surface. However, the strands retain a different level of surface brightness than is present on the surrounding coated areas of film 15 of the bulb. A spherical or glittering of light is effected by a particular filtration of the spectrum.

Instead of using a separate lacquer coating, or film, over the overcoating 4 to produce color filtration, the overcoating 4 itself can be modified by using an inorganic or organic pigment as a selective filter of emitted and incident light. This inorganic or organic pigment is mixed with the overcoat material 4. Incorporation of the colorant directly into the overcoat 4 accomplishes satisfactory transparency with resin systems designed for high temperature service. This is particularly useful in utilizing the present invention with high wattage rating lamps. The novel effects produced by this embodiment are similar to those provided by the embodiment previously described in FIG. 5 wherein the film 15 is used except the degree of clarity in the areas between the strands is lowered due to the use of the pigment-type colorant.

The strand pieces 2 also can be provided with a suitable colorant system prior to their being applied to the lamp. In this case the adhesive coating 3 and protective overcoat 4 are applied to the lamp 6 in the manner previously described with .both of these coatings being transparent. The strand pieces 2 are colored with a dye or pigment or they may be stained. They are applied to the lamp envelope in the same manner previously described with respect to FIGS. 12. The contrasting surface brightness between the strand pieces 2 and the other clear coated areas of the bulb 6 is enhanced by making the strands colored. In this case, only the strand pieces 2 selectively filter visible transmitted light when the filament 9 is energized or selectively reflect visible incident light when the filament is nonenergized.

Other novel effects can also be obtained by coloring two or more of the lamp components, for example: (1) the adhesive and the strands; (2) the overcoat 4 and the strands; (3) the strands and the film or any other combination, with the same or different colors.

In addition to providing a novel decorative effect to a lamp, the present invention also uses a coating system which increases the shatter resistance of the glass envelope 6 against physical impact as well as thermal strains. The random positioning of the strand pieces 2, the overlying relationship of some of the pieces 2 (as shown in FIG. 3) and their intimate contact with the adhesive and protective overcoat forms a matrix which increases the resistance to shattering of the glass envelope 6 if the lamp is dropped or handled in a manner to cause fracture of the bulb. The lamination of the adhesive coating 3 and protective overcoat 4 produces a thickness of cured resins of low thermal conductivity sufficient to provide high resistance for transmittance of temporary temperature variations between the outer coating surface and the surface of the glass envelope. The glass envelope often reaches temperatures which if not protected against rapid temperature variations would fracture under the typical conditions of an energized high wattage unprotected gas filled glass envelope exposed to spattering of cold fluids or to outdoor precipitation.

The use of glass fiber strand pieces allows a maximum of light transmittance as a decorative medium for the effects produced by the lamp of the subject invention.

While preferred embodiments of the invention have been described, it will be understood that these are illustrative only, and the invention is to be limited solely by the appended claims.

lclaim:

ll. An electric lamp comprising an envelope of vitreous light transmitting material, means within said envelope for producing light in the visible range, an adhesive material coated on said envelope, and a plurality of individual elongated strands of light transmitting material formed by at least one fiber whose length is substantially greater than any other dimension, each of said strands having a length in the range from about one-eight inch to about three-quarters of an inch and having a degree of flexibility along the length thereof to enhance conformance to the overall outer contour of the envelope, said strands being distributed on the envelope in a random pattern with areas of the'envelope being free of the strands and various ones of said strands overlying one or more other strands, all of said strands being bonded to said envelope by the adhesive material along a substantial portion of the lengths thereof.

2. A lamp as set forth in claim I wherein the strands of light transmitting material comprise pieces of a multifilament yarn.

3. A lamp as set forth in claim 1 further comprising a first layer of coating material over said strands and said adhesive.

d. A lamp as set forth in claim 2 further comprising a first layer of coating material over said strands and said adhesive.

5. A lamp as set forth in claim 1 wherein said adhesive is colored to filter light of a predetermined wavelength.

6. A lamp as in claim ll wherein said strands are colored to filter light of a predetermined wavelength.

7. A lamp as in claim 3 wherein said first layer of overcoat material is colored to filter light of a predetermined wavelength.

8. A lamp as in claim 3 further comprising a second layer of a coating material over said first layer, said second layer being colored to filter light of a predetermined wavelength.

9. A lamp as set forth in claim 3 wherein said adhesive material, strands and first layer are substantially clear and colorless.

110. An electric lamp as in claim ll wherein said strands of light transmitting material are of fiberglass.

1111. An electric lamp as in claim 3 wherein said strands of light transmitting material are of fiberglass.

Claims

1. An electric lamp comprising an envelope of vitreous light transmitting material, means within said envelope for producing light in the visible range, an adhesive material coated on said envelope, and a plurality of individual elongated strands of light transmitting material formed by at least one fiber whose length is substantially greater than any other dimension, each of said strands having a length in the range from about one-eight inch to about three-quarters of an inch and having a degree of flexibility along the length thereof to enhance conformance to the overall outer contour of the envelope, said strands being distributed on the envelope in A random pattern with areas of the envelope being free of the strands and various ones of said strands overlying one or more other strands, all of said strands being bonded to said envelope by the adhesive material along a substantial portion of the lengths thereof.

2. A lamp as set forth in claim 1 wherein the strands of light transmitting material comprise pieces of a multifilament yarn.

4. A lamp as set forth in claim 2 further comprising a first layer of coating material over said strands and said adhesive.

6. A lamp as in claim 1 wherein said strands are colored to filter light of a predetermined wavelength.

10. An electric lamp as in claim 1 wherein said strands of light transmitting material are of fiberglass.

11. An electric lamp as in claim 3 wherein said strands of light transmitting material are of fiberglass.