RU2009390C1 - Auxiliary head-light automobile lamp - Google Patents

Abstract

FIELD: automobile manufacture. SUBSTANCE: polyellipsoidal head lamp has a specially-shaped diaphragm with a mirror surface formed by a family of circular arcs of different curvature. EFFECT: improved light beam intensity and reduced color effect on the light and shade boundary. 3 cl, 4 dwg

Description

 The invention relates to lighting equipment, in particular to the design of automotive headlights of the projector type.

 Known polyellipsoid headlights are a structure consisting of a polyellipsoid reflector, a light source, a collective lens, coaxial with the reflector, and a diaphragm located between the reflector and the lens.

 In these headlights that implement the projection principle of forming a light beam of a certain direction, the cut-off border of the light beam is formed by a diaphragm that shields the light rays emanating from the bottom of the reflector. As a result, a significant part of the luminous flux of the light source is completely absorbed by the diaphragm.

 Known designs of ellipsoidal phases of low beam, in which various elements are installed, allowing the use of part of the shielded diaphragm light rays.

 The closest technical solution, selected as a prototype, is a headlight in which the diaphragm in the part facing the light source has a reflecting spherical surface centered in the second (external) focus of the circularly symmetric ellipsoid reflector, and reflects the incident rays backwards, along their original direction. These rays reflected by the diaphragm, having reflected twice more from the reflector, are included in the creation of the light flux of the headlight.

The disadvantages of the prototype are:
the prototype diaphragm design cannot be used in headlights with non-circular symmetric ellipsoid reflectors, because the reflecting part of the diaphragm surface has a spherical shape;
- the chiaroscuro border of the light beam of the headlamp is formed by a horizontal edge from the cut out part of the spherical surface of the diaphragm located at a considerable distance from the external focus of the reflector, which makes it difficult to optimize the use of the light source concentrated in the external focus of the reflector.

 The aim of the invention is to increase the efficiency and reduce the color effect at the chiaroscuro border of the light beam of the dipped headlight, achieved by the fact that the headlight contains a polyellipsoid reflector with a common apex and the same internal focus, a light source installed in the internal focus of the reflector, the diaphragm reflector and collective lens.

 Comparative analysis with the prototype shows that the proposed low beam phase differs from the prototype in that the reflective surface of the reflector has a polyellipsoid shape; the surface of the reflecting part of the diaphragm-reflector is formed by a family of arcs of circles of different curvatures; the apex of the arcuate edge of the reflector diaphragm, forming the border of the chiaroscuro of the light flux of the headlight, is located in the focal plane of the first external focus of the vertical meridional section of the reflector or near it.

 In FIG. 1 shows a polyellipsoid dipped-beam phase in a vertical axial section; in FIG. 2 - the same headlamp in a horizontal axial section; in FIG. 3 is a front view of a reflector and a diaphragm reflector; in FIG. 4 - a separate diaphragm reflector.

The headlight contains: a polyellipsoid reflector 1 with an optical axis 2, the eccentricity of the generating ellipses of which gradually increases from its vertical meridional section to the horizontal meridional section, with the vertex F common to all ellipses and the focus F _in the vertical meridional section and focus F _g in the horizontal meridional section;
- a light source 3 mounted in the focus F of the reflector;
- a diaphragm-reflector 4 with a convex mirror surface 5 facing the light source 3, with an edge 6 having a horizontal plane view of a circular arc centered on the optical axis or a convex curve, the vertex of which is located _in or near the focal plane of the focus F , and a flat horizontal surface 7 with fastening elements of the diaphragm in the headlamp housing (not shown) located at a certain distance below the optical axis, in order to make it possible to project the edge 6 onto a plane perpendicular to the optical axis 2 profiles forming the chiaroscuro border of the corresponding contour;
- collective lens 8, coaxial with the reflector.

The mirrored convex surface of the diaphragm 4 is formed by a family of arcs of circles of different curvature, the centers of which are on the optical axis 2 within the focal length of the reflector F _in -F _g , while the radii of the arcs of circles are determined by the equation
R _n = 2x (an-av) + R _in , where R _n is the radius of curvature of the surface in the diaphragm section by the plane in which the light rays reflected from the nth meridional section of the reflector lie;
an - the semimajor axis of the ellipse in the n-th meridional section of the reflector;
av - the semimajor axis of the ellipse in the vertical meridional section of the reflector;
R _in - the radius of curvature of the convex surface of the diaphragm in a vertical axial section centered at the focus of F _in .

Thus, the curvature of the convex surface of the diaphragm gradually decreases from the radius R _in with the center at the focus F _in the vertical meridional section to the radius R _g with the center in the focus F _g in the horizontal meridional section.

 As can be seen from FIG. 1 and 2, due to the presence of a specular reflecting surface 5 formed by arcs of circles according to the above equation, every ray 9 emanating from a light source 3 and incident on the lower part of the surface of the reflector 1 is reflected from it in a direction perpendicular to the surface 5 of the diaphragm reflector and, therefore, reflected from the diaphragm-reflector and reflector, will pass near the focus F, and, once again reflected from the upper part of the reflector, will fall on lens 8, thereby increasing the light flux of the headlight.

 The incident on the lens 8 of additional radiation reflected by the surface 5 of the diaphragm-reflector 4 at angles slightly different from the angles of incidence of radiation emanating directly from the filament of the lamp and reflected by the reflector on the lens 8, can somewhat reduce the chromatic aberration of the light flux of the headlight.

 (56) Italian Patent N 2622276 (8813851), cl. F 21 M 3/05, 1988.

 German patent N 3523029A1, class F 21 M 3/14, 1986.

 German patent N 3241713A1, class F 21 M 3/04, 1984.

 German patent N 3802097A1, class F 21 M 3/14, 1989.

 German patent N 3226580A1, class F 21 M 3/06, 1983.

 French patent N 2550847, cl. F 21 M 3/05, 1983.

Claims (3)

 1. A CAR DARKLIGHT, comprising a polyellipsoid reflector with a common apex and an internal focus F, a light source mounted at the focus of the reflector F, a collective lens coaxial with the reflector, a reflector diaphragm located between the reflector and the lens and forming the beam beam characterized in that the diaphragm-reflector is made with a mirrored reflecting surface of a convex shape facing the light source formed by a family of arcs of circles of different curvatures. 2. The headlight according to claim 1, characterized in that the centers of the arcs of circles forming the convex surface of the reflector aperture are located on the optical axis within the limits of the focal length F _in - F _{g of the} reflector and the radii of the arcs of circles are determined by the equation
R _n = 2 · (a _n - a _in ) + R _in ,
where R _n is the radius of curvature of the surface in the cross section of the diaphragm by the plane in which the light rays are reflected from the nth meridional section of the reflector;
a _n is the semimajor axis of the ellipse in the n-th meridional section of the reflector;
a _in - the semimajor axis of the ellipse in the vertical meridional section of the reflector;
R _in - the radius of curvature of the convex surface of the diaphragm in a vertical axial section centered at the focus of F _in . 3. The headlight according to claim 1, characterized in that the diaphragm-reflector is made with a negative surface with an arcuate edge, the vertex of which is in the focal plane of the focus F _{in the} reflector or near it, located at some distance below the optical axis to give the projection of the edge onto the plane perpendicular to the optical axis, the profile forming the corresponding contour of the chiaroscuro border of the light beam of the headlamp.

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