Cool Light

Abstract

A device for producing cool light utilizing a dichroic reflector wherein the reflected visible light is directed to a second reflector which redirects the light to a diffuser.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of application Ser. No. 328,961 filed Dec. 9, 1963 and now abandoned.

Description

This invention relates to the use of dichroic reflectors in the production of cool light.

It is often desirable, and sometimes necessary, to have a cool light for observation purposes and for general working purposes. For example, with the light bar it is necessary, when inserting the light bar into the apertures of the human body, to have a cool light. If a light having a considerable amount of infrared is used, it is possible to sear and damage the tissues of the body. Accordingly, it is an object of this invention to provide a clear, cool light having a relatively small amount of infrared rays; to provide an indirect, clear, cool light; to use a flat substrate having a dichroic reflecting surface and which is relatively inexpensive; to use a curvate substrate having a dichroic reflective coating on the convex surface of the substrate; to use in combination a flat substrate having a dichroic reflective coating and a curvate substrate having a dichroic reflective coating; to use a cool light with a light bar; to provide polarized, cool light; to provide liquid absorption means for absorbing infrared rays from light; to provide a low-angle, cool light for use close to the ground; and, to provide a relatively inexpensive means for producing cool light.

These and other important objects and advantages of the invention will be more particularly brought forth upon reference to the accompanying drawings, detailed description of the invention and the appended claims.

In the drawings:

FIG. 1 is a side-elevational view of a means for lighting by indirect, cool light;

FIG. 2, taken on line 2-2 of FIG. 1, is a longitudinal horizontal cross-sectional view and illustrates some of the details of the construction of FIG. 1;

FIG. 3 is a side-elevational view of two flat substrates having a dichroic reflecting coating on the inner surface, a means for producing both visible and infrared light rays and a flat substrate having a dichroic reflective coating;

FIG. 4 is a side-elevational view of a flat substrate having a dichroic reflective coating and a means for producing both visible and infrared rays;

FIG. 5 is a side-elevational view of four pieces of flat substrate having a dichroic reflective coating and a light means for producing visible and infrared light rays;

FIG. 6 is a side-elevational view of a single curvate substrate having a dichroic reflective coating on one surface and a means for producing visible and infrared light rays;

FIG. 7 is a side-elevational view of one piece of curvate substrate and three pieces of flat substrate and a light means for producing visible and infrared rays;

FIG. 8 is a lateral cross-sectional view of a substrate having a dichroic reflective coating on one surface;

FIG. 9 is a lateral cross-sectional view of a light bar and a means for producing cool light for said light bar;

FIG. 10 is a lateral cross-sectional view of a means for producing cool light;

FIG. 11 is a lateral cross-sectional view of a light bar and means for producing polarized, cool light for said light bar;

FIG. 12 is a fragmentary side-elevational view of a curvate substrate, a light means and means for dissipating infrared light rays;

FIG. 13 is a fragmentary side-elevational view of two flat substrates having a dichroic reflective coating on their surfaces, a means for producing both visible and infrared light rays, and a means for absorbing and dissipating the infrared light rays;

FIG. 14 is a fragmentary side-elevational view of a means for a low-angle lighting and which may be inserted in the ground for use on an airfield runway; and,

FIG. 15 is a fragmentary side-elevational view of a modification of a low-angle lighting for use on an airfield runway.

Prior to presenting specific details of construction of various inventions, I will mention briefly dichroics and dichroic reflecting materials. Dichroic reflecting materials may be such as to transmit visible light rays and reflect infrared light rays and, also, to transmit infrared light rays and to reflect visible light rays. Visible light rays may be considered to have a wave length of approximately 380 -- 760 millimicrons, and infrared light rays may be considered to have a wave length in the range of approximately 760 -- 1500 millimicrons. This includes both the near and far infrared. A dichroic reflecting coating is placed on a suitable substrate such as glass, boro-silicate glass or organic plastic. A glass which will transmit both infrared and visible light rays is suitable. The coating is of first surface multilayer thin film and comprises alternate layers of higher and lower indices of refractive materials. At the present time there are many materials suitable for dichroic reflective films. More particularly, a dichroic film having suitable properties for transmitting infrared light and for reflecting visible light rays may comprise as a substrate glass or suitable organic plastic composition consisting of a film of metallic elements and compounds such as titanium, silicon, antimony sulfide, or with thin film or films of a dielectric material or of materials of such thicknesses or indices of refraction as to minimize the reflectance for those wave lengths of the infrared. The dielectric films may consist of materials such as zinc sulfide, magnesium fluoride, quartz, aluminum oxide, and magnesium oxide. The films should have an optical thickness equal to one quarter of the wave length of the near infrared, i.e., 760 -- 1500 millimicrons. More particularly, a glass or plastic reflector may be coated with alternate layers of high and low refractive indice materials of such thickness as to transmit approximately 20 percent of visible radiation, i.e., thin film layers being coated with a layer of zinc sulfide or other dielectric materials and having an optical thickness of approximately 250 millimicrons. Another type of reflector employing multiple coatings of pairs of dielectric films to increase a visible reflectance is disclosed in U.S. Pat. No. 2,660,925, Turner. In regard to a dichroic for transmitting visible light rays, there may be a substrate of glass or suitable organic plastic having a dichroic film. There films are known at the present time and may consist, for example, of extremely thin coatings of a metal such as gold, or suitable sulfides. For example, see U.S. Pat. Nos. 1,342,984, Bugbee; 1,425,967, Hoffman; and, 2,379,790, Dimmick. Other United States patents which are of interest in regard to dichroic thin films are Schroder, U.S. Pat. No. 2,668,478; Turner, U.S. Pat. No. 2,519,722; Schroder, U.S. Pat. No. 2,852,980; Schroder, U.S. Pat. No. 2,700,323; Kock et al. U.S. Pat. No. 2,742,819; Browne, U.S. Pat. No. 2,087,821; and Kraus, U.S. Pat. No. 2,861,896.

Dichroic thin films, on a suitable substrate such as glass, may be secured from numerous commercial suppliers such as: Balzers, Furstenten, Lichtenstein; Optical Coating Laboratories, Inc., Santa Rosa, California; and Liberty Glass Division, Liberty Owens Ford, Breckenbridge, Pennsylvania.

Suitable sources of light are well known. For example, there may be used carbon arc sources of light, the inert gases for sources of light such as neon, argon, and xenon. There may be used cadmium for a source of light. Also, there may be used a source of light based on the tungsten-iodine principal. This has been disclosed in U.S. Pat. No. 2,883,571, Fridrich et al. All of these sources of light contain both visible light rays and infrared light rays.

In FIG. 8 there is illustrated a substrate 20 of a suitable glass or suitable organic plastic for a dichroic reflective layer 22. It is seen that this dichroic reflective layer is composed of alternate coatings of a quarter-wave length of high-index refraction and low-index refraction materials. These coatings may be such as to be of a quarter-wave length in thickness so as to function as a dichroic reflective coating. It is to be understood that FIG. 8 is merely presented as a schematic illustration of a dichroic reflective coating 22 on a glass substrate. Also, instead of seventeen layers, as shown in this figure, there may be any other number of layers. From practical experience, I have found that a glass substrate having 17 layers provides a fine dichroic reflector.

In FIGS. 1 and 2 there is illustrated means for producing an indirect cool light by the use of dichroic reflectors. This indirect lighting means 22 comprises an elongated channel 24 having a base 26 and two parallel legs 28. Connecting with the upper leg 28 is a housing or flat plate 30. Connecting with the lower leg is a housing 32 of a flat-plate construction having for a downwardly directed leg 34. The plate 30 connects with another plate or housing 36 and which housing 36 turns downwardly into a leg 38. The downwardly directed members 34 and 38 have a positioning means 40 for positioning the diffuser plate 42. This diffuser plate 42 may take numerous different configurations and be constructed of various materials such as a flat piece of glass, either frosted or clear, or a flat piece of plastic of a commonly known eggcrate or louvered configuration, or a textured glass or plastic. On the inner face of the housing member 36 there is a reflective material 44 such as a corrugated or patterned material, glass, plastic, a painted surface or metal. In the channel member 24, it is seen that there is positioned two dichroic reflector materials 46. These materials 46 have a flat substrate 48 and on the first surfaces there is a reflective coating 50. The reflective coating 50 is highly reflective of visible light rays and is highly transmissive of infrared light rays. Therefore, it is seen that the light rays from a light source 52 are reflected towards the reflective material 44 and, therefore, reflected downwardly through the diffuser 42. The light source 52 may be a carbon arc mercury or other enclosed arc or a lamp based on the tungsten-iodine principal.

With this arrangement of two flat dichroic reflectors, it is seen that a large percentage of the infrared light passes through the reflectors and only a small percentage reaches the reflective surface 44. Also, most of the visible light rays are reflected surface 44. Also, most of the visible light rays are reflected from the dichroic reflectors and reach the reflective surface 44 and are directed downwardly through the diffuser 42. The net result is that there is produced a relatively cool light.

In FIG. 3 there is schematically illustrated the combination 60 of dichroic reflectors and a light source. It is seen that there are two reflectors 62 at an angle to each other. These two reflectors comprise flat substrates 64 and on the first surface a dichroic reflecting material 66. Between these two reflectors 62 there is a light source 68. In front of the light source 68 and substantially in front of the two reflectors 62, there is a third reflector having a flat substrate 72 and a dichroic reflective surface 74. In this instance, the light source 68 gives off waves in the visible light region and in the infrared region. The dichroic reflecting material 66 is highly reflective of visible light rays and highly transmissive of infrared light rays. The substrate 64 is transmissive of infrared light rays. Further, the dichroic reflecting coating 74 on the reflector 70 is highly transmissive of visible light rays and highly reflective of infrared light rays. As a result, it is seen that substantially all of the infrared light rays which strike the reflector 70 are reflected away from it and though the reflector 62. Also, the visible light rays from 68 are reflected away from the reflector 62 and passes through the reflector 70. The net effect is that the visible light rays passing through the reflector 70 are substantially free of infrared rays and are a cool light.

In FIG. 4 there is illustrated a dichroic reflector 80 having a flat substrate 82 of glass or an organic plastic or other suitable material, and a reflective coating 84. Positioned adjacent the reflector 80 is a light source 86. In this instance, the reflective coating 84 reflects visible light rays and transmits infrared rays. As a result, the net effect is that a large percentage of the infrared light rays are transmitted through reflector 80, and there is produced a relatively cool light. Another important result is that the light source will operate at a reduced temperature due to the infrared rays not being reflected into the lamp or light source as would the situation be if the thin film coating 84 were not used.

In FIG. 5 there is illustrated a combination 90 comprising four flat reflectors. Three of these reflectors 92 are arranged with the center reflector and a reflector on each edge at an angle with respect to the center reflector. These reflectors comprise a flat substrate 94 of glass or other suitable material having a dichroic coating 96. Adjacent these three reflectors is a light source 98. In front of the light source 98 is a reflector 100 having a flat substrate 102 and a dichroic coating 104. It is seen that the light source 98 is substantially surrounded by the reflectors 92 and 100. The reflective coating 96 on the substrate 94 is highly transmissive of infrared light rays and highly reflective of visible light rays. The reflective coating 104 on the flat substrate 102 is highly transmissive of visible light rays and highly reflective of infrared light rays. The net result is that most of the infrared light rays from the light source 98 pass through the three reflectors 92 and most of the visible light rays pass through the reflector 100. In this manner there is produced a cool light substantially free of infrared rays.

In FIG. 6 there is illustrated a curvate reflector 110 having a curvate substrate 112 of glass or of any other suitable material and on the convex surface of the substrate 112 there is a reflective coating 114. Juxtapositioned next to the reflective coating 114 is a light source 116. The reflective coating 114 is a light source 116. The reflective coating 114 is highly transmissive of infrared light rays and highly reflective of physical light rays. The net result is that a high percentage of infrared rays from the light source 116 are transmitted through the reflector 110 and a high percentage of the visible light rays are reflected from the reflective coating 114 so as to produce a substantially cool light.

In FIG. 7 there is a side-elevational view of a combination 120 of three flat reflectors and one curved reflector. Two of the flat reflectors 122 have a substrate 124 of glass or other suitable material and a reflective coating 126. There is a curvate reflector 128 having a curved substrate 130 of glass or other suitable material and on the convex surface is a reflective coating 132. A light source 134 is positioned adjacent the curvate reflector 128 between the two flat reflectors 122. There is a flat reflector 136 having a flat substrate 138 of glass and other suitable material and a reflective coating 140. The light source 134 gives off visible light rays and infrared light rays. The reflective coatings 126 and 132 are highly transmissive of infrared light rays and highly reflective of visible light rays. The reflective coating 140 is highly reflective of infrared rays and is highly transmissive of visible light rays. The net combination of this is that the infrared light rays are reflected from the reflector 136 and are transmitted through reflectors 122 and 128. Also, the visible light rays are reflected from the reflectors 122 and 128 and are transmitted through the reflector 136. The visible light rays which are transmitted through reflector 136 contains substantially no infrared light rays and, therefore, are a cool.

Some of the advantages of the configurations of FIGS. 3 through 7 are that the reflectors are easily mounted and positioned in reflectors due to their being flat or one-piece curvate reflector. Also, these configurations are relatively easy to focus the light rays.

In FIG. 9 there is illustrated a side-elevational view of a light bar apparatus 150. This apparatus comprises a light bar 152 and which light bar may be fiber optic of glass fiber or methyl methacrylate or other suitable material. The light bar 152 connects with a positioning means 154. This positioning means has a frustum-of-a-conelike end 156 and which frustum-of-a-conelike end 156 connects with cylindrical member 158. The cylindrical member 158 connects with another frustum-of-a-conelike member 160 and which frustum-of-a-conelike member 160 connects with a cylindrical member 162. The light bar 152 is positioned in the end of the frustum-of-a-conelike member 156. In that part of the cylindrical sleeve 162 near the light bar 152 there is a lens positioning member 164. This lens positioning member 164 has a center passageway 166 and a cylindrical shoulder 168. In the cylindrical shoulder 168 there is a collimating lens 170 and a condensing lens 172. Positioned away from the condensing lens 172 is a larger collimating lens 174 and another condensing lens 176. There is a cool light source for the light bar 152. This light source 152 comprises two flat reflectors 178. The reflectors 178 are positioned at an angle to each other and comprise a flat substrate 180 of glass or other suitable material having a reflective coating 182. Positioned between these two flat reflectors 178 is a light source 184. Positioned above the two flat reflectors 178 and above the light source 184 is another flat reflector 186 having a flat substrate 188 of glass or other suitable material and a reflective coating 190. The reflective coatings 182 and 190 are highly transmissive of infrared light rays and are highly reflective of visible light rays. As a result it is seen that a majority of the infrared light rays pass through the reflectors 178 and 176 and almost all of the visible light rays are reflected from the reflector 186 toward the condensing lens 176. Surrounding the reflectors 178 and 186 is a black anodized aluminum screen 192. This screen 192 absorbs much of the radiant energy in the infrared light rays and becomes warm. There is a case 194 for the light source and the screen 192 and which case has a bottom wall 196, side walls 198 and top walls 200. In the top wall 200 there is an outlet 204. Connecting with this outlet 204 is a suction fan 206. It is seen that a black anodized screen 192 absorbs the infrared light rays and becomes warm. The fan 206 draws air through the housing 194 and which air circulates around the screen 192 and conducts away heat from the screen. Also, some heat is dissipated by convection. In this manner the screen 192 is cooled.

In FIG. 10 there is schematically illustrated a side-elevational view of a source of cool light 210 which may be used for printing purposes and in the developing of color film and the like. The structure of the cool light source 210 is substantially the same as the structure of the cool light means 150 and, therefore, like reference numerals will be used for similar components of the structure 210. It is seen that the collimating lens 170 transmits a source of cool visible light and which light is substantially free of all infrared light rays. These cool light rays, free from the agitation of infrared rays, are desirable for printing purposes and for use in developing color film and for use in developing black and white film.

In FIG. 11 there is illustrated another light bar means 212. This light bar means 212 comprises a light bar 213 connected to an end 216. The end 216 is attached to a frustum of a cone 218. This frustum of a cone 218 is attached to a cylindrical light member 220. In the cylindrical light member 220 there is a polarizer 222. The polarizer 222 is between the light bar 214 and a cooling means having two light transmitting members 224. Between the two light transmitting members 224 there is a cooling liquid 226 such as water. A pipe 228 may connect with cylindrical sleeve 220 and allow liquid circulation between the light transmitting members 224. The tubular housing 220 connects with the housing for the light source, the collimating lens and the dichroic reflector. More particularly, the lower part of the housing 220 connects with the housing 230 having an opening 232. The housing 220 and the housing 230 are at right angles to each other. As is seen in FIG. 11, the left end of the housing 230 is covered by an integral perforated end plate 234. Also, the right end of the housing 230 is covered by an end plate 236. The end plate 236 is in a diagonal with respect to the housing 230 and has a number of passageways 238 therein. The inner surface of the end plate 236 may be of black material to absorb infrared energy. As is readily appreciated, the passageways 238 allow air circulation through the end plate 236 so as to absorb the heat. The end plate 236 may be considered to be at a right angle to the longitudinal axis of the housing member 230. In this end plate it is seen that there is positioned a reflector 240 having a flat substrate 242 of glass or suitable organic material and A dichroic reflective coating 244 on the substrate. The reflector 240 is highly transmissive of infrared light rays and highly reflective of visible light rays. Positioned in the housing 230 is a collimating lens 246. Between the collimating lens 246 and the end plate 234 is a light source 248. Between the light source 248 and the end plate 234 is a dichroic reflector 250 having a substrate 251 and a dichroic reflective coating 253. Connecting with the reflector 250 is a bolt 252. This bolt 252 passes through the end plate 234 and outside of the end plate 234 is a nut 256. It is seen that by adjusting the nut 256, it is possible to vary the position of the reflector 250 so as to vary the reflection of the visible light rays from the light source 248. From this arrangement it is seen that a large percentage of the infrared light rays are transmitted through the reflectors 250 and 240 and the heat is dissipated by air around the end plates 234 and 236 and the passageways 238. The visible light rays are reflected from the reflector 240 and passed through the cooling solution 226 and also through the polarizer 222. The cooling solution 226 takes out substantially all of the remainder of the infrared light rays. In the light bar there is cool polarized light.

In FIG. 12 there is illustrated in a schematic side-elevational view a curved dichroic reflector 260 having a curved substrate 262 of glass or suitable organic material and a dichroic reflective coating 264 on the concave side of the substrate 262. On the concave side of the reflector 260 there is a light source 266. The reflector 260 and the light source 266 are positioned inside of a curved cooling means 268 having a hollow tubular interior 270. Connecting with the upper end is a pipe 274. By means of these pipes it is possible to flow a cooling agent such as water 276 through the cooling jacket 268. As the reflector 260 is highly transmissive of infrared light rays and highly reflective of visible light rays, it is seen that a large percentage of the visible light rays from the light source 266 are reflected outwardly and that a large percentage of the infrared ray from the light source 266 are transmitted through the reflector 260 to the housing 268. The concave surface of the housing 268 may be of a blackened material, e.g., housing 268 may be a black anodized aluminum to absorb the infrared energy. The cooling agent 276 by conduction picks up the heat from the housing 268.

In FIG. 13 there is a fragmentary schematic side-elevational view of another light source and cooling means. In this view the cooling means 268 is the same as in the cooling means in FIG. 12 and like reference numerals will be used. There is a light source comprising gaseous filament type or carbon arcs 280. There are two flat reflectors 282 having a flat glass or organic substrate 284 and a dichroic reflective material 286 on the surface. The reflectors 280 are at an angle to each other. As is seen in FIG. 13, the angle is approximately a 90.degree. angle. The light source 280 is close to the juncture of the two edges of these reflectors 282. The reflectors 282 are highly reflective of visible light rays and highly transmissive of infrared light rays. It is seen that a large percentage of the visible light rays are reflected away from the reflectors 282 and a large percentage of the infrared light rays pass through the reflectors 282 to the black surface of the housing 268. The cooling liquid 276 carries away most of the heat energy from the housing 268.

In FIG. 14 there is illustrated a side-elevational fragmentary schematic view of a low-angle lighting means 290. The lighting means 290 comprises a housing having sidewalls 292, a bottom 294 and a top wall 296. The top wall 296 is connected by means of a hinge 298 with one side 294. In the top 296 there is an opening 300. Over the passageway and at approximately an angle of 45.degree. thereto is a reflective covering 302 having a polished inner surface. A light transmissive plate 304 is in the passageway 300. Connecting with the upper part of the covering 302 and the covering 296 is a light transmissive lens 306. A source of cool light comprises the two flat reflectors 310. The reflector 310 comprises a flat substrate 312 of glass or other suitable organic plastic and a dichroic reflective material 314. The reflector 310 is highly reflective of visible light rays and highly transmissive of infrared light rays. It is seen that the two reflectors 310 are at an angle to each other with the common interior angle being approximately 60.degree.. A light source 316 is positioned between the two reflectors 310. The infrared light rays from the light source 316 are transmitted through the reflectors 310 and the visible light rays from the light source are reflected from reflectors 310 upward to light transmitting plate 304 and are reflected from the reflective surface 301 through light transmitting plate 306. The lighting means 290 is positioned in the ground 318 with the cover 296 substantially flush with the ground. It is readily seen that with such a lighting means adjacent a runway there is provided a cool visible light on the runway. From experience I have found that this cool visible light is more visible at a distance than light having a mixture of visible light rays and infrared light rays. More particularly, a light having a mixture of visible light rays and infrared light rays apparently cuts down the visibility of the light. I am not sure of the reason for this, but one reason may be that the energy imparted to the gas molecules by the infrared light rays is such as to disturb the lighting effects and cut down the effective lighting. From practical experience I have found that visible light rays in the absence of infrared light rays gives a light which is more visible at a distance than a mixture of visible and infrared light rays. In this regard I have let some of my acquaintances who are colorblind look through a dichroic reflective coating. Some of these colorblind acquaintances have said that after looking through a dichroic reflective coating they could see colors.

In FIG. 15 there is illustrated a modification of a light means 290 in that flat plate 306 is replaced with a prism 320. Also there is a housing 322 with louvers 324 in front of the beam of light. These louvers, to a degree function as a collimator.

The applicant has observed the light from a curved reflector having a reflective coating transmissive to infrared light rays and reflective to visible light rays with the source of light being positioned with respect to the concave side of the curved reflector or curvate reflector. Also, the applicant has observed the light rays from a source of light and reflected light wherein the source of light is positioned near and in the interior angle of two flat reflective members and with the said flat reflective members having a reflective coating which is transmissive to infrared light and reflective to visible light. In comparing the light from the curvate reflector with the light from the two flat reflectors, the applicant has noticed that the light from the two flat reflectors appears to be clearer and more uniform than the light from the curvate reflector. The light from the curvate reflector adds striation with bright bands of light and dark bands of light and gives light of a varying intensity which indicates interference patterns in the light from the curvate reflector. The applicant directed light from the curvate reflector onto a flat reflective surface and also directed light from the two flat members onto a flat reflective surface. The light from the curvate reflector on the flat reflective surface had varying bands of intensity or striation or interference patterns. The light from the two flat members on the flat reflective surface was more uniform and did not show, to the eye, bands of varying intensity or striations or interference patterns. In many instances, it is possible to use, interchangeably, light from a curvate surface and light from at least two flat reflective surfaces. However, in certain instances it may be desirable to use only light from at least two flat reflective surfaces or two flat reflective members as striations or interference patterns may not be pleasing. An example of this is on a stage or in a theatrical group. As is well known, light on a stage, at the present time, contains infrared light rays as well as visible light rays. With the use of only visible light rays and the major portion of the infrared light rays stripped away, the light on the stage is clearer and the actors and actresses are performing in a cooler atmosphere and, presumably, a more pleasing atmosphere. If the light has striations or interference patterns or is of varying intensity, the actors and actresses do not appear as well and also the background does not appear as well as if the light is uniform in intensity and is free of interference patterns. In these instances in a theatrical group or on a stage, it is more desirable to use light from at least two flat reflective members as compared with light from a curvate surface.

Claims

Having presented my invention, what I claim is:

1. A device for reflecting light rays, said device comprising a light source of visible light and infrared light, a reflector having a reflective coating which is highly reflective of visible light rays from the light source and highly transmissive of the infrared light rays from the light source, a reflective material, and a diffuser, said light source being juxtapositioned next to the reflector, said reflector being positioned to direct the visible light rays towards the reflective material, and said reflective material being positioned to direct the visible light rays to the diffuser.