DD240784A1 - SECONDARY SPOTLIGHT FOR THE HOMOGENEOUS LIGHTING OF A FLAECHE - Google Patents

Abstract

The invention relates to a secondary radiator for homogeneous illumination of a surface. It can be used in particular in photographic technology or in microscopy. The inventive secondary radiator is adapted in shape to the rotationally symmetrical basic structure of an object and is arranged outside the imaging beam path. The light enters preferably in several places in the secondary radiator, is here forwarded mainly by total reflection and leaves it diffusely scattered by a ring-shaped Lichtaustrittsflaeche in the direction of the surface to be illuminated. The particular advantage of the secondary radiator according to the invention is the possibility of adaptation to a lens and the homogeneous light emission.

Description

embodiment

The invention will be explained below using an exemplary embodiment. In addition shows

1: the plan view of a secondary radiator according to the invention, and FIG. 2: a sectional view according to FIG. 1

The secondary radiator according to the invention for the homogeneous illumination of a surface has the shape of a perforated plane-parallel plate and consists of translucent material. The outer contour corresponds to a cylinder jacket with eight lugs 1 for irradiation of the light. The shape of the lugs is chosen so that the incoming light is passed through total reflection. The inner contour corresponds to the lateral surfaces of two inside the plane-parallel plate with the top surfaces colliding truncated cones, wherein the axes of the truncated cones are identical to the cylinder axis. One of these two surfaces is the light exit surface 2.

The cone angle, which determines the skew of this light exit surface relative to the surface to be illuminated, is selected as a function of the scattering characteristic of the material of the secondary radiator and of the geometrical dimensions of the optical system into which the secondary radiator is integrated.

The secondary radiator is arranged in a preferred plane of the optical system in order to optimally adapt the illumination beam path to the imaging beam path.

To increase the luminous efficacy, all surfaces of the secondary radiator are mirrored down to the light inlet and outlet surface.

Claims (3)

Invention claim: 1. secondary radiator for homogeneous illumination of a surface having the shape of a perforated plane-parallel plate of translucent material, characterized in that the outer contour of the plane-parallel plate corresponds to a cylinder jacket, with at least one approach to the irradiation of the light and the inner contour of the lateral surfaces of two within the plane-parallel plate corresponds to the top surfaces colliding truncated cones, wherein the axes of the truncated cones are identical to the cylinder axis. 2. secondary radiator according to item 1, characterized in that all the outer surfaces are mirrored except for the light entry surfaces on the lugs for irradiation of the light and one of the two inner surfaces. 3. Secondary radiator according to item 1 or 2, characterized in that the outer contour defining surfaces of the neck are a tangential surface to the cylinder jacket and a perpendicular thereto cutting surface. For this 1 page drawings field of use The invention relates to a secondary radiator for homogeneous Ausieuchtung a surface. He is particularly suitable for illuminating the image plane of a lens, which z. B. in the photographic technique for pre-exposure is necessary to increase the sensitivity of the film material in the recording of faint objects, or in the microscopy for illumination of the object field. Characteristic of the known technical solutions In known devices for illuminating a certain level in an optical system, the light is generally introduced via splitter mirror or the like into the imaging beam path. In some cases, these additional optical components in the imaging beam path are undesirable, so that the illumination is effected by the arrangement of a plurality of primary radiators at the periphery of the plane to be illuminated or in a visually favorable plane. As a result, generally no sufficiently homogeneous illumination can be achieved. An improvement is achieved by the use of a light source which is adapted in shape to the periphery of the plane to be illuminated or to a plane optically favorable thereto. These are unsuitable for applications in which a particularly short exposure time is desired. As low proves to be a secondary radiator, as he z. B. in DD-PS 206 236 is shown. This secondary radiator is a plane-parallel plate with an elliptical outer contour. In one focal point is the primary light source and in the other focal point is the center of a conical bore whose outer surface is the light exit surface. As is known, the foci of an elliptical mirror are two points that are optically conjugate to one another, so that the entire light of the focused light source is imaged into the second focal point. By arranging the conical bore about the second focal point, however, a partial surface of the elliptical Ummantlung is not directly irradiated, so that the light intensity with which the annular light exit surface radiates, not distributed over the entire ring is equal and thus the achieved homogeneity of the irradiation of the surface is not sufficient for some purposes. In addition, the shape of the plate is bound to an ellipse and thus poorly suited for installation in an optical system with a rotationally symmetric basic structure. Object of the invention The aim of the invention is to illuminate the image plane of a lens homogeneously by simple means. Explanation of the essence of the invention The invention has for its object to provide a lighting device which is adapted to the rotationally symmetrical basic structure of a lens and is located outside of the imaging beam path. According to the invention this object is achieved with a secondary radiator for homogeneous illumination of a surface having the shape of a perforated plane-parallel plate of translucent material in that the outer contour of the plane-parallel plate corresponds to a cylinder jacket, with at least one approach to the irradiation of light, and the inner contour of the lateral surfaces of two within the plane-parallel plate corresponds with the top surfaces colliding truncated cones, wherein the axes of the truncated cones are identical to the cylinder axis. It is advantageous if all outer surfaces of the secondary radiator are mirrored except for the light entry surfaces and one of the two inner surfaces. The shape of the approach to the irradiation of the light is chosen so that the light is passed through total reflection. The light entrance surface is a sectional surface which runs at right angles to a tangential surface of the cylinder jacket. The particular advantage of the secondary radiator according to the invention is its shape, which makes it possible to arrange it outside the imaging beam path, without influencing the outer rotationally symmetrical shape of the lens.