US 3463914 A
Description (OCR text may contain errors)
Aug. 26, 1969 T. LUTTER LIGHTING ARRANGEMENT Inventor; THEOD R LUTTER mm wig United States Patent 3,463,914 LIGHTING ARRANGEMENT Theodor Lutter, Bochum, Germany, assignor to Original Hanan Quarzlampen GmbH, Hanan am Main, Germany Filed July 11, 1967, Ser. No. 652,557 Claims priority, applicatioiaogermany, July 30, 1966,
Int. Cl. F21v 33/00, 17/00 U.S. Cl. 2401.4 2 Claims ABSTRACT OF THE DISCLOSURE A lighting arrangement used as a surgical operating lamp including a cover plate disposed beneath its reflector having both an infra-red mirror and a light diffusing surface. The light diffusing surface is provided on the internal surface of the cover plate and includes a vapor deposited infra-red mirror which deflects the infra-red rays at lateral angles in order to prevent excessive heating of the reflector and the area illuminated by the visible light.
The present invention relates to an improved lighting arrangement which may be utilized as a surgical operating lamp.
More specifically, the present invention relates to a surgical operating lamp wherein the light which is reflected by the reflectors emerges through a light dispersion lens which serves also as the cover plate for the lighting arrangement.
In the construction of lighting arrangements, and particularly those used for surgical operations, it is desirable to provide sulficient dispersion of the light produced by the light source so that no shadows are cast onto the operating area. Moreover, the light dispersion which is provided in the lighting arrangement should also serve to reduce the amount of glare produced by the lamp.
In conventional lighting arrangements, and particularly those used for surgical operations, the inside of the cover plate is often covered with a permeable layer which reflects infra-red rays away from the area of the operation. This is important because only a small portion of the energy supplied to the light source, such as the light bulb, will be converted into visible light. The major portion of the energy will be directly converted into heat. For example, it has been found that the optical effectiveness of an electric light bulb is only about 4% so that approximately 96% of the energy supplied to the light bulb will be emitted as heat radiation and particularly infra-red radiation. Therefore, while it is desirable to concentrate the visible light towards a portion of the operating table, it is equally important to prevent as much as possible of the heat radiation from reaching the area of the operation. Conventional operating lamps utilize an infra-red mirror on the inside of the cover plate so as to prevent the infra-red heat rays from being transmitted to the area of the operation. The outer face of the cover plate is formed in such a manner so as to constitute a light dispersing surface. These conventional operating lamps, however, suffer from the disadvantage that the infra-red mirror reflects the infra-red heat rays back into the reflector of the lamp and thus produces additional heat around the operating light source.
Accordingly, the present invention provides a light dispersion surface within its cover plate which avoids a reflection of the infra-red heat rays back into the light source by providing a light dispersion surface on the inside of the cover plate so that the infra-red rays are diffused within the lighting arrangement. The light dispersion surface on the inside of the cover plate diffuses the visible light as it penetrates the cover plate thereby producing favorable lighting conditions in the operating area. On the other hand, the infra-red heat rays are also diffused by the same light dispersion surface of the inside of the cover plate containing the infra-red mirror so that only a small amount of the reflected heat reaches the reflector of the lamp while the largest portion of the heat is deflected laterally away from the lamp reflector. This type of heat deflection produces favorable heat convection conditions within the lighting arrangement.
It is therefore an object according to the present invention to provide a lighting arrangement for use over surgical operating areas which provides a diffused lighting condition over the operating area While dispersing away from the operating area a large portion of the infra-red heat radiation produced by the light source of the lighting arrangement.
It is a further object according to the present invention to provide a surgical operating lamp having a cover plate which difl'uses the visible light which penetrates the cover plate and deflects the major portion of the infra-red radiation away from the operating area and the reflector of the light source.
It is a further object according to the present invention to provide a surgical operating lamp which is simple in design, easy to manufacture and reliable in operation.
Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawing which discloses one embodiment of the invention. It should be understood, however, that the drawing is designed for the purpose of illustration only and not as a definition of the limits of the invention as to which reference should be made to the appended claims.
Referring to the drawing, the single figure discloses a lighting arrangement for use as a surgical operating lamp having a cover plate which serves as a light diffusing surface for both visible and infra-red radiation. A domeshaped mirrored lamp 10 is shown which permits a penetration of rays in the direction of the reflector 12 as indicated by the arrows. The reflector is a so-called cold light reflector known in the art, and reflects mainly the light portion symbolized by arrows 14, while a major portion of the infra-red rays symbolized by arrow 16 are passed through the reflector.
A cover plate 18 disposed below the reflector consists of a nondefracting light material so that the light will reach the area of operation through disk 20. The external surface 22 of disk 20 is smooth, while the inner surface 24 is provided with a light diffusing structure. An infrared mirror 26, designated by the broken lines on the drawing, is mounted or vapor deposited onto inner surface 24.
From the drawing it can be clearly seen how that portion 16a of the infra-red rays, reflected toward the cover plate by reflector 12, emerges as highly diffused rays 16b when reflected from infra-red mirror 26 mounted or vapor deposited on inner surface 24 of disk 20. The portion of the visible light 14a becomes highly diffused after penetrating disk 20, due to inner surface 24, and reaches the area of operation in a highly diflused condition. Since the diffused infra-red rays 16b are deflected away from the reflector and the operating area, undesirable heating of the operating area and the lighting arrangement can be avoided.
While only a single embodiment of the present invention has been shown and described, it will be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.
3 4 What is claimed is: said visible light to penetrate to said diffusing surface 1. A lighting arrangement for providing illumination for transmission to the working area. over a defined working area comprising: 2. The arrangement as recited in claim 1 wherein said a light source; light source comprises a dome-shaped mirrored lamp.
2. cold light concave reflector substantially surrounding 5 said light source for reflecting visible light while per- References Cited mitting a substantial portion of infra-red light to UNITED STATES PATENTS penetrate therehfmgh; 2,280,402 4/1942 Greppin 240-14 X a cover plate lens disposed 1n front of said reflector 1n 3 255 342 7/1966 Seitz et a1 240 1 4 the path of the reflected light; 10 n I a light diifusing surface formed on the internal surface NORTON ANSHER, Primary Examiner of said cover plate facing said reflector; and SIVERTSON Assistant Examiner an infra-red mirror, vapor-deposited on said light diffusing surface for deflecting a portion of said infra- US- red light away from said reflector and permitting 15 240-415