US3302015A

US3302015A - Flood-lighting luminaire

Info

Publication number: US3302015A
Application number: US370907A
Authority: US
Inventors: Dahlke Heinz
Original assignee: Siemens AG
Current assignee: Siemens Schuckertwerke AG; Siemens AG
Priority date: 1963-06-08
Filing date: 1964-05-28
Publication date: 1967-01-31
Anticipated expiration: 1984-01-31

Description

J81!- 31, H DAHLKE FLOOD-LIGHTING LUMINAIRE Filed May 28, 1964 INVENTORY Heinz Dohl ke Fig.2

ATTORNEY United States Patent 3,302,015 FLOOD-LIGHTING LUMINAIRE Heinz Duhlke, Traunstein, Germany, assignor to Siemens-Schnckertwerke Aktiengesellscliaft, Erlangen, Germany, a corporation of Germany Filed May 28, 1964, Ser. No. 370,907 Claims priority, application Germany, June 8, 1963, 5 45,220 6 Claims. (Cl. 240--4l.3)

In the case of luminaires employed for high output lamps of small dimensions, e.g. floodlights, it is frequently necessary to screen out the light source at the larger angles with respect to the vertical, e.g. from 80, because of the high intensity of illumination. It is known practice, in the case of floodlights fitted with a quartziodine incandescent lamp located within a channelshaped parabolic mirror, to incorporate thin screening plates in order to cut down the amount of glare. These thin broad plates, which are set parallel to the symmetry plane of the channel-shaped mirror, are located only in the upper half of the light-exit cross-section of the mirror. The light rays from the luminaire emerge in a well defined direction so that the major portion of the light is radiated out in the direction of the parabolas axis. In many cases, the fact that the region below the luminaire receives very little illumination constitutes a major drawback. In the illumination by means of floodlights of a building facade, a sporting arena, or an aircraft landing field, certain lighting conditions apply for which the light-exit apertures of the floodlights are placed at different positions. In the case where horizontal surfaces are to be illuminated, the light-exit aperture is tilted in a downward direction in such a way that the light reflected from the mirror is directed in a broad fan and with little vertical scatter onto the approximate center of the area to be illuminated. In such a case, the naked high-power lamp radiates glare-producing light directly out over a large angle and hence upwards into the air. Such light beams could seriously interfere with air traflic.

The present invention enables an improvement to be effected in a luminaire suitable for use in a high output quartz-iodine lamp of small dimensions which is located in a channel-shaped mirror and used as a floodlight, the said high-output lamp being provided with a means for deflecting the light. According to the present invention, the channel-shaped mirror also acts as a screen or cover for the auxiliary mirror serving the lamp and is fitted with a cover-glass equipped with prisms which serve to direct the light into the region located below the principal light-emitting direction of the channelshaped mirror.

The luminaire made in accordance with the present invention may, for example, be fitted with a quartziodine incandescent lamp or with a high pressure mercury vapor lamp. It is also possible to use a high pressure, high-output sodium vapor lamp in whose outer envelope is located a discharge tube which is about the same size as a pencil. Despite the high luminosity of these lamps, exceptionally good anti-glare characteristics are attained as a result of the screening in lamps, in accordance with the present invention. In the illumination of an airfield landing strip by means of a floodlight made in accordance with the present invention, the upward-directed light from the high-output lamp which could hinder air trafiic is screened by the auxiliary mirror, but it is not lost. The light falling on such auxiliary mirror is directed onto the channel-shaped mirror and reflected into the principal radiating direction. By this means, part of the light is so deflected by the mediately below the floodlights.

The invention is illustrated schematically in the accompanying drawings, in which:

FIGURE 1 is a vertical cross section of the luminaire of the present invention taken on the line 1-1 in FIG. 2;

FIG. 2 is a longitudinal section, on a reduced scale, taken through the axis of the luminaire shown in FIG. 1 on the line IIII;

FIG. 3 is a cross section of a luminaire cover-glass fitted with inward-facing prisms; and

FIG. 4 is a cross section of a luminaire cover-glass having inward and outward facing prisms.

The luminaire, shown for a high-output lamp of small dimensions, consists of a floodlight equipped with a quartz-iodine incandescent lamp 1, the latter being replaceable by a high-pressure mercury vapor lamp fitted with a clear glass outer envelope, or a high pressure high-intensity sodium vapor lamp fitted with an ellipsoidal outer envelope. The channel-shaped mirror 2 which encloses lamp 1 has, for example, a parabolic cross section with lamp 1 located on its focal line. The light rays are collected into a well-defined parallel bundle by means of channel-shaped mirror 2. Additional light deflectors are provided in order to obviate glare.

According to the invention, channel-shaped mirror 2 is fitted with an auxiliary mirror 3 and is closed by a cover-glass 4 which is provided with prisms. The additional light-deflecting means are accordingly constituted of auxiliary mirror 3 and prisms 5. In this regard, auxiliary mirror 3 simultaneously acts as a screen for lamp 1, while prisms 5 produce a deflection of part of the light, which would havebeen directed into the distance, into the region located below the main radiating direction H of channel-shaped mirror 2. This lower region is illuminated by rays I, II, III and IV. Appropriately, prisms 5 are situated in the lower-edge-region 6 of channel-shaped mirror 2, preferably in the approximate lower half of cover-glass 4.. For this purpose, prisms 5 are differently proportioned, i.e. their thickness increases as longitudinal edge 6 is approached and, as a result, rays IV, which are nearest longitudinal edge 6, undergo the greatest deflection, a deflection which is appreciably greater than that of rays I. The angle of diffraction of prisms 5 can vary in a continuous manner.

Prisms 5 can be advantageously formed on one or on both sides of cover-glass 4. In FIG. 1, prisms 5 are formed on the outside of cover-glass 4, in FIG. 3 they are formed on the inside, while in FIG. 4 they are shown formed on both sides of the cover-glass. It is also possible to apply only part of prisms 5 on the outside of a given cover 4, while other portions may be applied to the inside and also on both sides. Prisms 5 can also be located as far as symmetry plane S of channel-shaped mirror 2, but they can also terminate above or below this plane.

For convenience, auxiliary mirror 3 has the form of a channel whose cross section forms part of a circle. In this regard, the center of the circle, M, can be arranged to lie away from the axis of the lamp, and preferably on the periphery of the lamps enclosing envelope. The upper limiting edge 7 of auxiliary mirror 3 lies in a plane which is defined by the axis of the lamp and the upper longitudinal edge 8 of channel shaped mirror 2. The lower limiting edge 9 of auxiliary mirror 3 lies preferably in a plane which passes through the lamps axis and stands perpendicular to the light-exit planes of channel-shaped mirror 2. The lower limiting edge 9 of auxiliary mirror 3 can be arranged to lie in the symmetry plane S of channel-shaped mirror 2. The border-edges 10, 11 (FIG. 2) of auxiliary mirror 3 also lie in a plane which is defined by an end of lamp 1 and one of the short

limiting edges

12, 13 of the lightexit opening of channel-shaped mirror 2.

I claim as my invention:

1. A floodlighting luminaire comprising: an elongated channel-shaped primary mirror having a front opening and a focus describing a line; a high-intensity elongated integral lamp mounted along and proximate the focal line of said primary mirror; said luminaire having a main radiation direction for radiations generated by said lamp and reflected by said primary mirror; a lighttransmitting cover member fitting over the front opening of said primary mirror, and said cover member divided into upper and lower sections; an elongated auxiliary mirror spaced from said lamp and positioned between said lamp and the upper section of said cover member to intercept direct radiations emanated by said lamp toward said cover member and above the main radiation direction of said luminaire; and prisms provided on the lower section of said cover member to retract light striking same into the region located below the main radiation direction of said luminaire.

2. The luminaire as specified in claim 1, wherein said prisms are substantially confined to the lower section of said cover member, and said prisms have such varying configurations that each prism refracts light downwardly more than that prism directly thereabove.

3. A floodlighting luminaire comprising: an elongated channel-shaped parabolic mirror having a front opening and a focus describing a line; a high-intensity lamp elongated integral mounted along and proximate the focal line of said parabolic mirror; said luminaire having a main radiation direction for radiations generated by said lamp and reflected by said parabolic mirror; a lighttransmitting cover member fitting over the front opening of said parabolic mirror, and said cover member divided into upper and lower sections; an auxiliary elongated mirror having a cross section which forms part of a circle whose center describes a line positioned slightly above the focal line of said parabolic mirror, and said auxiliary mirror spaced from said lamp and positioned between said lamp and the upper section of said cover member to intercept direct radiations emanated by said lamp toward said cover member and above the main radiation direction of said luminaire; and prisms provided on the lower section of said cover member to refract light striking same into the region located below the main radiation direction of said luminaire.

4. The luminaire as specified in claim 3, wherein the lower edge of said auxiliary mirror lies proximate a plane parallel to the main radiation direction of said luminaire and which passes through the focal line of said parabolic mirror, and the lower edge of said auxiliary mirror is approximately perpendicular to the main radiation direction of said luminaire.

5. The luminaire as specified in claim 3, wherein the upper edge of said auxiliary reflector lies proximate the plane described by the focal line of said parabolic reflector and the upper edge of said parabolic reflector.

6. The luminaire as specified in claim 3, wherein the upper section and the lower section of said cover member are of approximately equal size and said prisms are substantially confined to the lower section of said cover member.

References Cited by the Examiner UNITED STATES PATENTS 2,142,964 1/1939 Godley 240-414 2,277,563 3/1942 Scott et al. 240-4l.4 X 2,380,849 7/1945 Kolb 2404l.3 X 3,222,516 12/1965 Miles 2404l.3 X

JOHN M. HORAN, Primary Examiner.

NORTON ANSHER, Examiner.

C. R. RHODES, Assistant Examiner.

Claims

1. A FLOODLIGHTING LUMINAIRE COMPRISING: AN ELONGATED CHANNEL-SHAPED PRIMARY MIRROR HAVING A FRONT OPENING AND A FOCUS DESCRIBING A LINE; A HIGH-INTENSITY ELONGATED INTEGRAL LAMP MOUNTED ALONG AND PROXIMATE THE FOCAL LINE OF SAID PRIMARY MIRROR; SAID LUMINAIRE HAVING A MAIN RADIATION DIRECTION FOR RADIATIONS GENERATED BY SAID LAMP AND REFLECTED BY SAID PRIMARY MIRROR; A LIGHTTRANSMITTING COVER MEMBER FITTING OVER THE FRONT OPENING OF SAID PRIMARY MIRROR, AND SAID COVER MEMBER DIVIDEND INTO UPPER AND LOWER SECTIONS; AN ELONGATED AUXILIARY MIRROR SPACED FROM SAID LAMP AND POSITIONED BETWEEN SAID LAMP AND THE UPPER SECTION OF SAID COVER MEMBER TO INTERCEPT DIRECT RADIATIONS EMANATED BY SAID LAMP TOWARD SAID COVER MEMBER AND ABOVE THE MAIN RADIATION DIRECTION OF SAID LUMINAIRE; AND PRISMS PROVIDED ON THE LOWER SECTION OF SAID COVER MEMBER TO REFRACT LIGHT STRIKING SAME INTO THE REGION LOCATED BELOW THE MAIN RADIATION DIRECTION OF SAID LUMINAIRE.