United States Patent [151 3,648,235 Cahill [45] Mar. 7, 1972

[54] OPTICAL SYSTEMS FOREIGN PATENTS OR APPLICATIONS [72] lnventor: Michael R. Cahlll, Bellerose, N.Y. 396,789 Great Britain ...... ,...... 340/107 [73] Assignee: The Marbellte Company, Inc., Brooklyn, NY. - Primary Examiner-John W. Caldwell [22] Filed: July 15, 1970 Assistant Examiner-J. Michael Bobbitt Attorney-‘Wolf, ?eld & Sacks [211 Appl. No.: 55,060 [57] ABSTRACT , [52] US. Cl.,...... ,...... ,.....340/ll0, 240/4649, 340/382, _ A traffic signal apparatus for illuminating a message in al ' ~ ' ' 350/97 temate colors carries two light sources of different light color [5 l] Int. 3601] 1/00 outputs. A one~way light mirror is positioned about one of the [53] Field of Search .340/110, 106, 107, 382; light sources to allow passage of light therefrom and to re?ect 240/106, 46.49, 46.59, 41.35; 350/97, 291 substantially all light from an outside source such as the _ second light source. This optical system construction avoids l56] References cued unwanted light color re?ection on a message plate of the hous m m e. .m m N65 DBB CvkT. T"e E"t "a S P MI mm g“ mmrm mm3t mm mm .10dr. 6.5 .mumm mmU 83S muA 5.0I. .mE mm s Rw.8w meu Dhmm w? wmm m.mm FWm mmm m 32 0,8, 85 54 2,6, 25 40 49 300 3.3 44 00 ll 11 00 77 w l i PATENTEDHAR 1 I972. 3,648,235

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~ INVENTOR MICHAEL R. CAHILL FIG. 4 BY 9/” ,WMd’4JaabATTORNEYS 3,648,235 1 2 OPTICAL SYSTEMS It is a feature of this invention that the coating or one-way mirror means used is inexpensive and uncomplicated. BACKGROUND OF THE INVENTION Moreover, existing traf?c signal housings can be easily In conventional traf?c signals such, as WALK-DON'T modi?ed by replacement of colored bulbs with colored bulbs WALK signals, different colored light sources are used in a carrying the one-way mirror means or positioning of a single re?ector to illuminate the WALK portion of a message separate one-way mirror means element over the colored alone in one color at one time interval and sequentially to illu bulbs. minate the DON‘T and the WALK message in a second color BRIEF DESCRIPTION OF THE DRAWINGS at a second time interval. This often requires the use of two light sources behind a transparent WALK message stencil 10 The above and other objects, advantages and features of the plate such as an and a white incandescent lamp or bulb present invention will be better understood from the following positioned behind a transparent WALK message stencil plate. speci?cation when read in conjunction with the accompany When the orange lamp is illuminated, the WALK message ing drawings in which: appears orange since conventional orange coatings on such FIG. 1 is a diagrammatic front view of a traf?c signal hous lamps absorb all but the light‘ rays having the orange color ing and associated controller in accordance with the preferred wavelength and allow passage of only the orange light. How embodiment of this invention; ever, a problem arises when the orange lamp is not illuminated FIG. 2- is a semidiagrammatic front view of elements and the white lamp is illuminated to cause the WALK message thereof; to appear white. In this case, a portion of the white light which 20 FIG. 3 is a top plan view of the elements of FIG. 2; passes to the unlit orange lamp is altered in its color composi FIG. 4 is a cross-sectional view through the center of an ele ?'\n by the particular re?ective and absorptive properties of ment thereof; and, the orange coating of the unlit lamp causing an unwanted FIG. 5 is a semidiagrammatic showing of an alternate em orange re?ection to the WALK message. Thus, during illu bodiment thereof. mination of the white lamp, the WALK message is not entirely 25 white but has an orange cast to at least certain portions of it. DESCRIPTION OF PREFERRED EMBODIMENTS This orange cast is undesirable‘. Methods have been proposed for eliminating the undesirable re?ections but often involve With reference now to the drawings, an improved traffic complex optical systems or alternative traf?c signal housing signal control apparatus is indicated generally at 10 in FIG. I and is in the form of a WALK-DON’T WALK pedestrian constructions. 30 It is an object of this invention to provide an apparatus for signal. The complete apparatus comprises a housing 11 carry generating and transmitting two different light colors at al ing upper and lower re?ectors such as 12 forming a compart ternate time periods without obtaining an undesirable light ment behind each suitably masked transparent stencil panel re?ection from any unlit light source in the apparatus. 13 and 14 having transparent clear portions denoting the let Another object of this invention is to provide an apparatus ters of the DON’T and WALK signals, respectively. Within the in accordance with the preceding object in the form of a traf bottom re?ector 12 are positioned plural light sources com ?c signal apparatus having at least two light sources of dif prising lamps 15 and 16 of one color and lamp 17 of another ferent colors with one of the light sources being surrounded by color with the lamp 17 carrying the improved coating 22 of a one-way light mirror. _ this invention. The structural elements of the WALK-DON'T WALK will Still another object of this invention is to provide an ap 40 paratus in accordance with the preceding objects which is be brie?y described although it should be understood that all basically similar to conventional equipment and requires little elements described are well known in the art with the excep modi?cation to achieve the desired effect. tion of the use of the particular one-way mirror means com Still another object of this invention is to provide an ap— prising the coating 22 as will be more fully described. In accordance with conventional design, the apparatus 10 paratus in accordance with the preceding objects which is 45 highly ef?cient and uncomplicated. comprises an outer casing or housing 11 as of metal within which is positioned an upper parabolic plane re?ector (not SUMMARY OF THE INVENTION shown) having a front opening area in rectangular form An apparatus for generating and transmitting two different directly behind the rectangular DON'T stencil panel 13. light colors has a ?rst light source for generating light rays of a 50 Within the upper re?ector is a single light source 18 such as an ?rst predetermined color with the light rays having a ?rst orange color coated incandescent lamp. The lower parabolic predetermined wavelength. A second light source is provided re?ector 12 which is preferably identical to the upper parabol for generating light rays of a second color different from the ic re?ector (not shown) de?nes a front area adapted to lie ?rst-mentioned color. Re?ector means act to re?ect light directly behind the WALK stencil panel 14. The parabolic originating from both of the light sources to a predetermined 55 re?ector 12 has a rear re?ecting surface 20 designed to spread area. One-way mirror means are positioned about the ?rst all lightimpinging thereon throughout the area of the WALK light source for re?ecting light rays of the second color panel 14. impinging thereon generated by the second light source while As best shown in FIGS. 2 and 3, mounted within the re?ec permitting passage of light rays therethrough originating from tor 12 are three incandescent lamps with two of the lamps the ?rst light source. - 60 such as 15 and 16 acting as light sources of substantially white Preferably the apparatus is a traf?c signal apparatus such as light. A tinge of can be incorporated as by use of standard a WALK-DON'T WALK sign or other message-carrying sign lunar white lamps. The third light source comprises a Portland where one portion thereof such as the WALK portion is orange lamp 17, best shown in FIG. 4, having a conventional formed by a translucent or transparent front stencil panel in Portland orange ceramic coating 21 and a thin white high tem the predetermined area. The light sources are preferably in 65 perature silicone type coating 22 of this invention thereover. candescent light lamps or bulbs, one of which has a color coat In order to better understand the invention, the operation of 3' such as an orange color coating surrounded by a second a conventional WALK-DON'T WALK signal having lamp 17 coating such as a white coating which acts as a one-way light of a conventional Portland orange lamp without the coating mirror. Light rays from the ?rst light source passing through 22 of this invention will ?rst be described. In such convention the orange coating are intense enough to pass through the 70 WALK-DON'T WALK signals, a conventional controller 23 white coating when the orange lamp is lit thus illuminating the actuates the single orange lamp 18 in the upper re?ector along message. When the white lamp is lit, re?ection of light at the with the orange lamp in the lower re?ector at one predeter white coating over the orange lamp causes re?ection of all mined time period so as'to obtain illumination of DON'I" wavelength light rays striking the white coating thus prevent WALK in orange during one time interval. During a second ing any orange cast on the message. 75 time interval, the controller acts to turn off the two orange 3,648,235 3 4 lamps and turn on the two white lamps in the lower re?ector sources 15 and 16 are re?ected while light rays emanating 12 causing illumination of only the WALK panel in a different ' from the light source 17 being of higher intensity than the out color (i.e., white) than the color obtained during the ?rst time side light rays impinging on the bulb, do pass through the coat interval. The lamps can be actuated to ?ash during the ing to the outside. Such light rays are high-intensity orange preselected time periods if desired, Standard time intervals light rays. While some cut down in the light output of the light and time periods of illumination of the two sets of lamps are source 17 does occur, this cut down is not signi?cant. commonly used in phase with traf?c stop-go-slow signals Similarly, a negligible portion oflight from the sources 15 and through suitable known electrical circuitry at an intersection. 16 may be absorbed by the coating 22 or passed therethrough. The problem is that during the time when the orange lamp 17 The spacing of the white lamps from the orange lamp and/or is unlit and the white lamps 15 and 16 are lit, light rays passing the light output intensity of the white lamps is predetermined from the polychromatic white lamps impinge on the unlit to assure re?ection of light therefrom by the one-way mirror orange bulb 17 as best seen by the arrows indicating light rays while permitting passage of light from the orange lamp. in FIG. 3. The impinging light rays have all components of the Similarly, the speci?c translucent white layer used and color polychromatic light absorbed by the orange coating with only producing layer of the light source 17 vary in accordance with 15 orange light of a wavelength corresponding to the orange known practice so long as the translucent layer allows passage color re?ected from the orange lamp to eventually pass out of colored light from the source yet re?ects polychromatic through the WALK panel giving an orange tint to the other light impinging thereon and originating from another source. wise white light or forms unexpected orange color spots on the In another embodiment of this invention, the translucent message panel. This orange tint is undesirable. 20 white layer 22 is eliminated from the bulb 17. Instead of a The reason for the undesirable re?ection is that the color of white layer, the one-way light mirror of this invention is an object such as the orange coating on the lamp 17 causes it formed by a ?lter element such as 30 positioned over a bulb to re?ect light rays of certain wavelength and absorb all other 17 not having the coating 22. The ?lter 30 can comprise a wavelength light rays. Thus, when the orange lamp is illu clear glass bubble having outwardly extending ?anges 31 for minated, all wavelength light produced does not pass through 25 attachment to the re?ector and carrying a coating 22A identi the orange coating but only orange wavelength light passes cal to the coating 22. In this case, the coating 22A functions as therethrough and from thence to the WALK sign. On the does coating 22. in some cases, element 30 can be an orange other hand, when the white lamps are illuminated since the colored element having a coating 22A thereon with the bulb white light transmits a polychromatic, composite beam con 17 being a clear or white bulb. taining light rays, some of which have wavelengths matching 30 The one

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