US2673923A - Means for producing colored light beams - Google Patents

Description

March 30, 1 R. G. WILLIAMS MEANS FOR PRODUCING commas LIGHT BEAMS asheetswsheet 1 Filed Dec. s, 1947 FIG. I.

F162. FIG. 8.

ci/m'p/e y F R. G. WILLIAMS March 30, 1954 3 Sheets-Sheet 2 Filed Dec. 3. 1947 FIG. 5.

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March 30, 1954 R, w s 2,673,923

MEANS FOR PRODUCING COLORED LIGHT BEAMS Filed Dec. 3, 194'? 3 Sheets-Sheet 3 FIG. 6.

Patented Mar. 30, 1954 MEANS FOR PRODUCING COLORED LIGHT BEAMS Rollo Gillespie Williams, Great Neck, N. Y., as-

signor, by mesne assignments, to Duro-Test Corporation, North Bergen, N. J., a corporation of New York Application December 3, 1947, Serial No. 789,516

1 Claim. (Cl. 240-3.1)

This invention relates to improvements in light of difierent color to provide illumination which can be blended into one final beam of light.

It is sometimes desired to mingle the light of a plurality of colors such, for example, as the four colors, white, red, green and blue, in such a manner that by blending the light in diiferent proportions difierent color hues are obtained. If four spotlights corresponding to these four colors are mounted close together, it will be found that undesirable color shadows are created and the four beams do not generally intermingle sufiiciently to avoid what is known as color fringing.

It is therefore desired that these beams should be so intermingled that the colors in question can be sufiiciently combined to avoid these phenomena, and an object of the present invention is apparatus whereby this result maybe achieved. It is to be understood, however, that this inven tion applies to the combination of any required number of colored light sources, and that the number "fo-ur is quoted as an example. Also, the sources can be arranged to give any desired color of light and means may be employed for varying the color and/or intensity of the useful emitted light. For example, in the case of a plurality of light sources, individual dimmers may be employed to vary the useful emitted light.

The expression useful emitted light used herein means the amount of light which is eventually used for illuminating or other purposes and if means, such as for example iris diaphragms are employed for. controlling the light from 'any light source, it will be appreciated that the amount of useful emitted light may be lessthan amount of light emitted (that is, produced) by the .source. According to the present invention, means are provided whereby a major light beam is split into a number of component beams; predetermined component beams are transposed and means are provided for combining the component beams into a unitary beam. The expression major beam is used as a matter of convenience to indicate a beam from any convenient source of light and includes where the context so permits, a plurality of beams derived from a single beam; specifically, it is employed (where the context so admits) to mean the flux of light allocated to any one color before the splitting takes place. According to one method of carrying the invention into effect, color light '2 ing apparatus is provided comprising a light source or plurality of light sources or other means affording a plurality of major beams of light, in combination with two optical systems, the first of which functions to split each major beam into a plurality of component beams and transposes some component beams or predetermined parts thereof and the second of which collects said component beams and transmits them as a unitary beam. The expression optical system as used herein means an arrangement of lenses, prisms, or reflectors, or any combination thereof.

Specifically, the first optical system is so constructed and arranged that the number of component beams into which each major beam is split, is preferably a multiple of the number .of colors to be mingled.

It is an object of the present invention to overcome the difiiculties mentioned above by means of the type generally indicated above.

Other objects will become apparent from the following description taken in connection with the attached drawings showing several illustrative embodiments of the invention and wherein: Fig. 1 is a horizontal sectional view of the apparatus (taken on the line l-l in Fig. 2).

Fig. 2 is an elevation of the first opticalsys- 'tem of Fig. 1. Fig. 3 is a diagram illustrating the manner in which the first system splits and transposes the beams emanating from the various sources, as viewed in the plane of the second optical system.

Fig. 4 is a. diagram illustrating how reflectors may be used in the optical systems.

Fig. 5 is a diagram illustrating the use of lenses and reflectors in the first optical system. Fig. 6 is a diagram illustrating a firstloptical system consisting of reflectors and a second op} t'ical system consisting of refracting prisms. and masks. Fig. '7 is a diagram illustrating an arrangement in which the emission of a single source is divided into a plurality of major beams.

It is to be assumed that it is desired to combine the light of four different colors emanating from four separate light sources, which may be referred to as R (for red), G (for green), B (for blue) and W (for white).

The four light sources may be mounted, say, in pairs one above the other so that each light source terms, say, a corner of a square or rectangle, each light source being more or less separ rated from the others. The desired hue of colored light can be provided by means of a color filter associated with each or selected of the light sources at any location between the source and the emergence of the final unified beam (e. g. the lenses of oneor each optical system may be made of colored glass) or each light source itself can. emit colored (including white) light.

From each source, there emanates a major beam; in Fig. 1 the major beams from sources R and G are indicated at IR; and. K respectively. In front of the light sources, there is a first optical system I, one function of which is to collect the major beam from each source andtransmit a plurality of separate narrow-angle (or parallel) component beams. on the drawings these component beams are given the reference: letter of the source from which they emanate, primed with "anindex number 1, 2, 3 or 4 as the case may be. There will preferably be as many component beams of light (or multiples of this numher) from each light source as there are fundamental colors to be mingled. Thus, if four colors are to be mingled in one final beam, the light collected from each source is divided into four (or multiples of four) separate beams of light. This can be done either by one composite lens or by a number of separate lenses suitably mounted for each light source.

Thus in the drawings the component beams are indicated at R R R R G G etc., the component lenses that constitute the first optical system are indicated at r r r T g g etc.

A further function of the first optical system I is to transpose certain or all of the component beams from the various sources so that their location, in a plane substantially normal to the general direction of light transmission is changed and a jumbling. or "scrambling" of the component beams results, On Fig. 2. arrows indicate the direction in which certain component beams are diverted' for this purpose, while Fig. 3 illustrates the resultant transposition at the second system and maybe considered as representing a. section taken in the said plane, showing the resultant patchwork effect.

All these component light beams. are transmitted to a second optical system (or straightener) 2 mounted at a convenient distance in front of the first system. The second system (of said Fig. 1) caneither take the form of one composite lens or may include a number of separate lenses suitably mounted and can be either larger or smaller in area than the first set of lenses or composite lens. 7

Some or all of the component beams of light from the first system i or set of lenses nearest to the light sources will enter thesecond system 2 or. set of lenses at an angle, but the second set of lenseswill bearranged tobring all the component beams into a parallelo-r nearly parallel direction "wtih each other, as illustrated in Fig. 1. To accomplish this, it is necessary for each separate lens (or section of a composite lens) in the first system I which transposes a beam, to have a corresponding lens (or part of a composite lens) in thesecond system 2. The second set of lenses (or part of a composite lens) will, however, be arranged in a different order.

Some of the component light beams from the first system may enter the second system direct, i. e'. not at an angle, but other component beams will be deflected by the first system, so as to enter the second system-at an angle, so that there will be a greater-distance between say, two component lightbea ms ofthe'sa'me color after passing through the second system than was the case when the light beams left the first system. The second system will, however, finally bring all the component light beams into one final narrow angle, or parallel beam of light of the kind provided by spotlights. In this manner, lights of different colors are more closely mingled 1 in one final beam.

In Fig. 4, the light from the sources of which R and G are examples, is collected and projected forward as parallel major beams IR and IG by parabolic reflectors 3 and 4 which pass through nests of black masking rings orslats 5 anld 6. These permit the passage of the light from the reflectors 3 and 4 without obstruction but substantially prevent the passage of light direct from the sources. Each major beam is broken up into its component beams by the first optical system and certain component beams from the two major beams are transposed. This is effected by allowing component beams R to pass straight ahead without interference but by deflecting component beams R G by strip reflectors T, 8. At the secondoptical system 2, beams R Gr again pass straight ahead, but component beams R G are straightened bystrip reflectors 9 and I0.

In Fig. 5, reflectors 3, 4' are employed to collect the light from each source into its major beam. The first optical system I comprises lens plates H and [2 with circular prisms formed thereon serving to straighten the major beams and reflectors i and S for splitting and transposing.

In Fig. 6 the major beam directed rearwardly from each source R and G is split into its component beams, and the required transposition is effected, by suitably shaped reflectors or reflector sections i3, i i, I5, 66 (one for each component beam of each initial color). The transposed beams R and G are directed by theirreflectors 14, I5 to the means (here shown as refracting prisms l1, (8) in thesecond system 2 by which they are straightened; in passage to the second system they are masked by plates I9, 20 which prevent the emergence of stray light. The component beams R G that are thrown. by reflectors l3, l6, straight forward to the second system also pass through masking plates I9, 2D for a like purpose; these plates also suppress light travelling directly forward from the sources R, G.

In Figs. 4 and 6 instead of reflectors behind the sources, the light from the sources may be col,- lected into parallel major beams by refracting means located in front of the sources.

It will be appreciated that instead of there being a plurality of separate and distinct light sources which, as hereinbefore. described, generate separate major beams, there may be a common source such as X in Fig. 'i, the light from which is divided into the plurality of major beams each of which is subsequently split into a number of component beams by means such asreflectors 2|, 22 one for each beam. There may, for example, be positioned in front of or behind a single light source a multi-colored filter indicated at 23. The filter may, for example, be in the form of a square divided into four equal squares and one of these squares is colored red, the other green, the third blue and the fourth clear. In this manner, from a single source of light, four major beams of four different colors are obtained and these four major beams are transmitted to the first optical system I and from thence 'to the secondoptical system 2 in the manner previously described. It will be appreciated that there may be any desired number of individual light sources giving a plurality of major beams in the manner described and redetermined component beams of said major beams are transmitted to the second optical system in accordance with the present invention.

Since these major beams all emanate from a common source X, their individual intensities cannot easily be varied by means of dimmers or the like. On the other hand, the amount of light finally utilized from each beam (and transmitted through the optical systems) may be varied by control means 24, 25 such as an iris diaphragm, movable shutter or shutters, or one or more movable lenses, through which the beams pass on their way to the first optical system I. Such means may be operated individually and/or collectively. For example, there may be a patterning mechanism which may be pre-set to afford a predetermined combination of settings of said controlling means and mechanism whereby the controlling means are adjusted in accordance with any selected combination. The first optical system illustrated in Fig. 7, comprises main lenses II and I2 and transposinglenses T 9 while thesecond system 2 comprises straightening lenses 27'2 and 29 The expression optical system and "lenses or set of lenses as used in this description is meant to cover the necessary prisms, lenses, or reflectors required to produce the desired collection and/or deflection of light rays and, in practice each lens may in fact be a composite lens, or a combination of lenses as required to carry out the desired control of the light rays.

The optical systems of any of the illustrative forms shown and described can. if desired, be arranged also to difluse or widen the angle of the final composite beam of light.

From the foregoing it will be seen that by the present invention a resultant light beam of any desired color hue can be obtained by employing either a plurality of light sources each emitting a major beam, the relative intensity of which may be varied as required, or by employing a single light source from which a plurality of major beams are obtained such as by the use of a multi-colored filter, it being understood that the relative intensity of said beams may be varied, as required, as by the use of shutters or die.- phragms.

It will be noted that the constructions shown and described will serve admirably to accomplish the objects stated above. It is to be understood, however, that the constructions disclosed above are intended merely as illustrative of the invention and not as limiting as various modifications therein may be made without departing from the invention as defined by a proper interpretation of the claim which follows:

I claim:

In a color lighting apparatus for producing a beam of colored light without color fringing, the combination of means aifording simultaneously a plurality of major beams of light each of a difierent color, a first optical system for splitting each major beam into a plurality of discrete beams of the same color as the corresponding major beam and transmitting all of said discrete beams onto distinct areas of an imaginary plane in a color interspersed pattern, and an optical system in said plane for transmitting said interspersed discrete beams as a parallel unitary beam.

ROLLO GILLESPIE WILLIAMS.

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