US3768070A - Two color pedestrian traffic signal with means for improving color rendition - Google Patents

Abstract

This invention provides a two color pedestrian traffic signal comprising a housing, an upper and lower reflector unit within said housing, at least one light bulb of a first color within the upper reflector unit, at least one light bulb of said first color and also at least one light bulb of a second color within the lower reflector unit, means to energize the light bulbs of the first color during one time interval, means to energize the light bulb of the second color during another time interval and a diffusing stencil in front of each reflector which is selectively illuminated, wherein the improvement comprises light flux barrier means, in the lower reflector, which is located between the light bulb of the first color and the lower stencil.

Description

[ 1 Oct. 23, 1973 United States Paten n 1 Lawton TWO COLOR PEDESTRIAN TRAFFIC SIGNAL WITI'I MEANS FOR IMPROVING COLOR RENDITION Lawrence LawiBiJi 'EFsIfi [52] 'U.S. Cl. 340/44 [51] Int. Cl G08g 1/00 [58] Field of Search 340/41, 42, 43, 44, 340/45, 105

[56] References Cited UNITED STATES PATENTS 3,368,l98 2/1968 Eikenberry et al. 340/44 X 3,l4l,l49 7/1964 Lawton 340/44 Primary Examiner--William C. Cooper Assistant Examiner-Thomas L. Kundert AttarneyS. Delvalle Goldsmith et al.

[57] ABSTRACT This invention provides a two color pedestrian traffic signal comprising a housing, an upper and lower reflector unit within said housing, at least one light bulb of a first color within the upper reflector unit, at least one light bulb of said first color and also at least one light bulb of a second color within the lower reflector unit, means to energize the light bulbs of the first color during one time interval, means to energize the light bulb of the second color during another time interval and a diffusing stencil in front of each reflector which is selectively illuminated, wherein the improvement comprises light flux barrier means, in the lower reflector, which is located between the light bulb of the first color and the lower stencil.

9 Claims, 6 Drawing Figures in II 4? PATENIEDumzs m5 sum 10F 2 FIG,

FIG. 3

PAIENIEBnmesms I 3168,070

, SHEET 20F 2 TWO COLOR PEDES'IIRIAN'JTRAFFIC SIGNAL WITH MEANS son IMPROVING COLOR RENPIITION BACKGROUND OF THE INVENTION sive period. I obtained a patent on sucha device U.S.

Pat. No. 3,141,149, which was issued on July 14, 1964,

the disclosure of which is herein incorporated by refer- I ence.

1. Field of the Invention I The two color pedestrian traffic signal usually comprises a housing, an upper and lower reflector unit within said housing, a light bulb of a first color within the upper reflector unit, a light bulb of said first color and also a light bulb of a second color within the lower reflector unit, means to energize the light bulbs of the first color during one time interval (usually the prohibitory period), means to energize the'light bulb of the second color during another time interval (usually during the permissive period), whereby diffusing stencils in front of the reflectors and facing the pedestriansview are selectively illuminated. The diffusing stencil may in fact be a diffusing plate and separate opaque stencil, in combination. The reflectors in the housing unit are preferably parabolic.

There is no color tint problem when red is used during the Dont Walk phase and green is employed during the Walk phase. Green is a pure spectrum color and contains no red light. Consequently, during the green Walk phase, there is no illumination of the red light bulb becauseit will only reflect red light.

A problem does arise when non-pure colors are used. For example, a problem arises when orange is used for the prohibitory phase and white is used for the permissive phase. White is a mixture of all of the spectrum colors. During the permissive Walk phase, the white light flux results in some orange light being reflected from the unlit orange bulb. This causes an orange tint on the Walk stencil.

2. Description of the Prior Art There is a presently adopted method of eliminating the orange (or similar) ting during the permissive Walk period. This is accomplished by placing a translucent white coating on top of the orange coating of the orange bulb. During the white Walk phase, the white light flux reflected from the orange bulb is reflected as white light. This method is unsatisfactory because the added white layer on the orange bulb reduces the amount of useful orange light flux produced by this bulb during the orange Don't Walk phase. The additional white layer also increases the cost of manufacturing each orange bulb. The cost factor is important because bulbs are replaced many times during the lifetime of the signal apparatus.

It is therefore an object of this invention to provide a means of eliminating the orange tint during the white Walk period without a significant loss of orange light flux during the Dont Walk" period.

Another object of the invention is to provide such means in a manner which will eliminate the necessity of adding a white coating on the orange bulb.

SUMMARY OF THE INVENTION I have discovered that the orange (or similar) tint does not principally result from the white light flux being reflectedfrom the orange bulb to the reflector and thence towards the Walk" stencil. I have found that orange tint existed because the viewers eye looked through the front diffusing stencil plate and, in effect, saw a diffused image of an orange colored object. This object is the unlit orange bulb illuminated by ambient white light. I have further found that the orange tint is substantially eliminated by placing a light flux shield between the orange bulb and the front stencil plate. For complete coverage of the diffusing stencil, I have found that'the shielding element should preferably be a separate structural means located near the orange light bulb.

DESCRIPTION or DRAWINGS FIG. 1 illustrates a front view of the traffic signal,

'borken at the midpoint, and showing the front cover and stencil plates;

FIG. 2 is a cross section of the trafflc signal, taken along the lines 2-2 of FIG. 1, illustrating the reflector units and the outside housing;

FIG. 3 represents a front cross sectional, view taken along the lines 3-3 of FIG. 4 illustrating the outside housing and the reflector units;

FIG. 4 represents a sectional plan view along the lines 4-4 of FIG. 2 showing the parabolic reflector and the three bulbs of the lower reflector unit;

FIG. 5 shows a front elevation of the message panel of the'signal showing both Dont and Walk" illuminated in orange;

FIG. 6 is a similar view showing Dont unlit and Walk illuminated in white. I

Referring to'the drawings for a more detailed description of my improved traffic light, the case consists of a rectangular housing 1, open at the front and a cover 2 for closing the front side of the case. Cover 2 is pivoted at its lower edge by hinges 3 and is closed at the top edge by draw'bolts 4, pivoting horizontal on vertical posts 5 attached to housing 1, and having wing nuts 6 which engage ears 7 attached to front cover 2.

Two reflector units 8 and 9 are positioned one above the other within the housing 1. These reflector units are identical except for the number of light source receptacles 10. The upper reflector 8 has one receptacle whereas the lower reflector 9 has three receptacles. Each reflector unit consists of a parabolic reflector surface 11 having plane reflectors 12 attached to the top and bottom of the parabolic reflector surfaces. The light receptacles 10 are held by the lower plane reflecting surfaces 12. Each reflector unit has hinge pins 13 attached for supporting the units in housing 1. Pins 13 extend into holes of angle brackets 14 providing a pivotal mounting for each of the reflector units. The other side of the reflector has pin 16 cooperating with a spring latch 15 on the housing.

The diffusing stencil plates 17 are placed on the inside of the front cover 2. These plates are shown in front elevation in FIGS. 5 and 6. The message is formed by having the opaque stencil 18 covering the transparent diffusing screen 19.

In the upper reflector unit 8 there is an orange color coated type A incandescent bulb 20. A similar orange light source 21 is located in the lower reflector unit 9. White light is provided by white color coated type A bulbs 22 which are illuminated during the Walk phase.

During the permissive phase, the white colored light produced in the lower reflective unit 9 illuminates the surface of the unlit orange color coated bulb 21. To prevent the viewer from seeing the diffused orange colored image of bulb 21, a shielding structure 23 is placed near this bulb and is located between this bulb and the diffusing screen 19.

The front surface of the shielding structure 23 (the surface of the shielding structure which faces the diffusing screen 19) may be painted white or otherwise treated so as to reflect ambient light forward towards the diffusing screen. During the Walk phase, white light, originating from the white colored bulbs 22, strikes the opaque stencil 18 and then is reflected to the front reflecting surface of the shielding structure 23 and thence to the diffusing screen 19.

The wider the shielding structure, the greater will be the interference with the useful rays of light proceeding from the respective light sources towards the diffusing screen 19. I have found it desirable that the shielding structure be placed so that it cuts off light flux passage only between the orange bulb 21 and the central portion of the diffusing screen 19.

l have found that increased efficiency is obtained by material. It is also beneficial to have the light flux barrier assume a shape which approximates the shape of the orange bulb. l have also found it desirable to place the shield in close proximity to the orange bulb.

The inner surface of the shielding structure 23 (the surface of the shieldingstructure which faces the orange bulb) is preferably highly reflective so that when said orange bulb is energized and lit during the prohibitory period the maximum orange light will reach the viewer as a result of the reflection of the orange light from the reflecting surface of the shield by subsequent reflection, e.g., from the parabolic reflector.

While the preferred embodiment of this invention has been described with respect to orange and white color-snow preferred in ped estri an signals, it'is apparent that it is equally applicable to any combination where two colors are employed.

As is the usual practice in pedestrian traffic signals, the housing l'is also provided with a light shade 24 to prevent external light from causing excessive glare on the outer stencil plate surface. The shield 23 may also be hinge mounted to the reflector plate 12 to permit easier access to the orange bulb 21.

Other modifications of the invention may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A two color pedestrian traffic signal comprising a housing, an upper and lower reflector unit within said housing, at least one light bulb of a first color within the upper reflector unit, at least one light bulb of said first color and also at leasi one light bulb of a second color within the lower reflector unit, means to energize the light bulbs of the first color during onetime interval, means to energize the light bulb of the second color during another time interval and a diffusing stencil in front of each reflector which is selectively illuminated, wherein the improvement comprises light flux barrier means, in the lower reflector, which is located between the light bulb of the first color and the lower stencil.

2. A signal, as set forth in claim 1, wherein the barrier means is located near the first light bulb.

3. A signal, as set forth in claim 1, wherein the front surface of the barrier means is a reflecting surface.

4. A signal, as set forth in claim 1, wherein the barrier means has the approximate silhouette of the first light source.

5. A signal, as set forth in claim 1, wherein the light flux barrier means is comprised of a sheet of rigid material.

6. A signal, as set forth in claim 1, wherein said first color is orange and said second color is white.

7. A signal, as set forth in claim 2, wherein said barrier means is located between the light bulb of the first color and the central portion of the lower stencil plate.

I QTA signal, as set forth in claim 1, wherein the inner :surface of said barrier means is a reflecting surface.

Claims (9)

1. A two color pedestrian traffic signal comprising a housing, an upper and lower reflector unit within said housing, at least one light bulb of a first color within the upper reflector unit, at least one light bulb of said first color and also at least one light bulb of a second color within the lower reflector unit, means to energize the light bulbs of the first color during one time interval, means to energize the light bulb of the second color during another time interval and a diffusing stencil in front of each reflector which is selectively illuminated, wherein the improvement comprises light flux barrier means, in the lower reflector, which is located between the light bulb of the first color and the lower stencil.

2. A signal, as set forth in claim 1, wherein the barrier means is located near the first light bulb.

3. A signal, as set forth in claim 1, wherein the front surface of the barrier means is a reflecting surface.

4. A signal, as set forth in claim 1, wherein the barrier means has the approximate silhouette of the first light source.

5. A signal, as set forth in claim 1, wherein the light flux barrier means is comprised of a sheet of rigid material.

6. A signal, as set forth in claim 1, wheRein said first color is orange and said second color is white.

7. A signal, as set forth in claim 2, wherein said barrier means is located between the light bulb of the first color and the central portion of the lower stencil plate.

8. A signal, as set forth in claim 1, wherein the inner surface of said barrier means is a reflecting surface.

9. A signal, as set forth in claim 1, wherein said barrier is pivotally mounted to permit easier access to the shielded bulb.

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