JPS6042703A - Reflection mirror for lighting apparatus - Google Patents

Abstract

PURPOSE:To obtain a reflection mirror having good efficiency by providing a diffuse reflecting surface having a regular wave shape on the face of a main reflection mirror so that diffusivity of a specified angle is given to the light reflected by the main reflection mirror. CONSTITUTION:If parallel rays 1, 2 fall onto a spherical convex or concave mirror having a radius (r) of curvature and diameter (d), the reflected light 1', 2' are made into the diffused light having 2theta spread if the angle between the diameter and center of curvature of the reflecting surface is designated as theta. The light made incident on each microelement is regarded to be parallel rays and the reflected light is the diffused light having 2theta spread when the distance between a light source and the reflection mirror is substantially large as compared with the diameter (d) of the spherical mirror. If the light source is at a relatively near distance and the angle between the microelement and the light source is designated as alpha, the diffusion angle of the reflected light is 2theta+alpha and if further the size of the light source cannot be neglected, the diffusion angle is 2theta+alpha+beta where the angle of the light source viewed from the reflecting surface is designated as beta.

Description

DETAILED DESCRIPTION OF THE INVENTION When the light emitted from a light source is irradiated onto an object using a reflecting mirror, the light reflected from all points (micro elements) on the reflecting mirror is focused on the object. The purpose of this invention is to provide a reflecting mirror that diffuses light with a constant diffusion angle.

When irradiating light emitted from a light source using such a reflecting mirror,
When looking at the reflecting mirror from the subject side, light is emitted from the entire opening of the reflecting mirror, and the reflecting mirror forms a large surface light source.

Therefore, the shadow of the object produced by irradiation is extremely soft, and no harsh shadows are produced, making it extremely desirable as a general illumination device.

This type of reflecting mirror that has been used in the past is made by making small marks with a hammer or the like on the entire mirror surface, and the size and depth of the marks are not uniform, so the light diffusion angle lfi It is almost impossible to obtain uniformity. Furthermore, the method of roughening the mirror surface by sandblasting has the disadvantage that the diffusion angle becomes too wide, which significantly reduces the light collection efficiency.

In the reflecting mirror according to the present invention, the diffusion angle of each element is constant over the entire surface of the reflecting mirror (for example, 30° or 60°).
Since the light is not diffused beyond a certain value, there is no loss due to over-diffusion of reflected light, resulting in an extremely efficient reflecting mirror. Not only that, but the reflected beam angle is clearly constant, so if you look at the instrument from a place outside the beam angle, there will be no glare at all! It has the advantage of not being

Next, the present invention will be explained in detail. Now, as shown in Figures 1 to 4, when a parallel ray of 1.2 magnitude is applied to a concave spherical mirror or a concave spherical mirror with radius of curvature r and diameter d, the angle of the diameter of the reflecting surface with respect to the center of curvature is θ. Then, the reflected light 1', 2
' etc. become diffused light with a 2θ spread. Consider a case in which each minute element of the reflecting mirror consists of a convex spherical mirror, a concave spherical mirror, or alternately double spherical mirrors. If the distance between the light source and the reflecting mirror is sufficiently large compared to the diameter of the spherical mirror, the light incident on each microscopic element can be regarded as parallel rays, and the reflected light is 2
The light becomes diffused light with a spread of θ. If the light source is relatively close and the angle of the minute element with respect to the light source is α, then the diffusion angle of the reflected light is 2θ+α. Further, if the size of the light source cannot be ignored, and if the angle formed by the light source viewed from the reflective surface is β, then the diffusion angle will be 2θ+α+β. The 2θ diffusion angle is constant regardless of the magnitude and direction of the incident angle, and the magnitude of the diffusion angle can be arbitrarily set by selecting the diameter and radius of curvature of the minute element.

Figures 5a and 5b show a concrete example in which the shape of the reflecting mirror is an elliptical cylindrical reflecting mirror, the minute element giving a constant diffusivity is a convex or concave cylindrical surface, and its generatrix is an elliptical shape. This figure shows a tube reflecting mirror formed parallel to the generatrix. Light emitted from the light source F1 at the first focus of the ellipse1.
If 2.3.4 mag. does not have a diffusing surface, all of its reflected light will be concentrated at the second focal point F2, but if it has a diffusing surface, it will have a fixed diffusion angle centered on the line from the reflective surface to F2 (Fig. is 3
0° case)) with diffused lights 1', 2', 3', 4
' etc., and its center line passes through F2.

If the second focal point F2 is brought to infinity, the elliptical cylinder becomes a parabolic cylinder, and the reflected light becomes diffused light with an opening of 30° from the opening of the reflecting mirror. In the case of an elliptical cylinder or a parabolic cylinder reflector, the focal point is a straight line, and if a linear light source (for example, a bar-type halogen bulb or a bar-shaped fluorescent lamp) is placed at that position, the focal point will be in a direction perpendicular to the longitudinal direction of the light source. A certain angle planned for (
In the above description, it is possible to irradiate diffused light of 30°. On the other hand, since the light source has a wide spread in the longitudinal direction as it is, in order to limit this to a certain range, the purpose can be achieved by dividing the longitudinal direction into several parts using louvers or the like. In this case, the same effect can be obtained even if the light source is not a linear light source but a point light source.

Since the shape of a parabolic tube or an elliptical reflecting mirror is inevitably subject to some manufacturing errors, as well as errors in the position of the light source, in order to alleviate the unevenness of illuminance caused by these errors, as shown in Figure 6, If the generatrix of the wavy diffuse reflection surface formed on the main reflector is not parallel to the generatrix of the main reflector but intersects at a certain angle (for example, 30° or 45°) and the two wavefronts intersect, the main reflection can be achieved. Viewed from the front of the mirror opening, the diffused light is at a constant angle in the direction perpendicular to the generatrix of the diffuse reflection surface, and due to the intersection of the generatrix, the direction of the diffused light also intersects, and they complement each other to reduce unevenness in brightness from the irradiated surface. It becomes extremely rare.

In the above explanation, we omitted the explanation of the direct light that goes directly from the light source to the irradiated surface, but if there is no need to limit the beam angle, leave it as is, and if necessary, return it to the main reflector using the cylindrical reflector. , the light can be diffused at a constant angle.

The above explanation deals with the case of a cylindrical reflecting mirror, but if the reflecting mirror is a rotating body, such as an ellipsoid of revolution or a paraboloid of revolution, the generatrix of the wavy diffuse reflecting mirror can be set as shown in Figure 7. ,
It can be composed of a meridian passing through the rotation axis of the reflecting mirror and a number of concentric circles centered on the rotation axis. Further, as shown in FIG. 8, the right and left-handed spiral curves can be formed symmetrically intersecting a logarithmic spiral forming a constant angle with the concentric circles. If the left and right spirals are configured to be perpendicular to each other, the light diffused from the diffuse reflection surface will be diffused in the 90' vertical and horizontal directions with the same diffusion angle, so the entire object can be diffused in all directions to completely reach the purpose. . The diffusion angle of a spiral diffuse reflection surface is proportional to the radius from the center of the mirror.If the radius of curvature inside the diffuser surface is increased and the central angle of the diffuser surface is kept constant, the diffusion angle can be kept constant. I can't help but feel disappointed.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram showing the mode of operation of one embodiment of the reflecting mirror according to the present invention, FIG. 2 is a principle diagram showing the mode of operation of another embodiment, and FIGS. 3 and 4 are diagrams showing still other embodiments. FIG. 5a is an explanatory diagram showing the overall mode of operation of the reflecting mirror of the present invention, FIG. 5b is an enlarged view of the 0 point, and FIG. FIG. 7 is a schematic front view of another embodiment, and FIG. 8 is a schematic front view of still another embodiment. Patent applicant Masaaki Arai 6 Figure 7

Claims (1)

[Claims] A reflector for a lighting device that consists of a light source and a reflector, in which a regular wavy diffuse reflection surface is provided on the surface of the main reflector so that the light reflected by the main reflector has a certain angle of diffusivity.