DE10004699B4 - Vehicle headlights according to the projection principle - Google Patents

Abstract

Vehicle headlamp according to the projection principle with a light source (14), with a reflector (10), through which light emitted by the light source (14) is reflected as a converging light beam, with an aperture arranged in the beam path of the light beam reflected by the reflector (10) ( 18), through which part of the light beam is shielded, with a lens (26) arranged in the light exit direction (13) after the diaphragm (18), through which an upper edge (20) of the diaphragm (18) serves as a light-dark boundary (83, 84) of the light beam emerging from the headlamp is imaged, at least one shielding element (40) being arranged at a distance below the optical axis (11) between the diaphragm (18) and the lens (26), which shielding element (40) partially extends into the beam path of the reflector (10 ) reflected light beam, characterized in that the shielding element (40) is arranged so that it partially shuts off part of the light beam reflected by the reflector (10) irmt, which would cause lighting at a short to medium distance in front of the vehicle, and that it has on its side facing the lens (26), in the light exit direction (13) facing a reflection surface (42), which is a part of the opposite to the Reflected light inside direction (27) of the lens (26) reflected light so that it passes through the lens (26) and above the chiaroscuro boundary (83, 84) of the reflected by the reflector (10), passing the diaphragm (18) and through the lens (26) passing light beam.

Description

State of the art

The invention relates to a vehicle headlight according to the projection principle according to the preamble of claim 1.

Such a headlight is through the DE 43 15 401 A1 known. This headlight has a light source and a reflector, is reflected by the emitted light from the light source as a converging light beam. In the beam path of the light beam reflected by the reflector, a diaphragm is arranged, through which a part of the light beam is shielded. In the light exit direction after the diaphragm, a lens is arranged, through which an upper edge of the diaphragm is imaged as a light-dark boundary of the emerging from the headlight beam. The light-dark border avoids dazzling oncoming traffic. At least one reflection element is arranged between the diaphragm and the lens, through which light is reflected in at least one region arranged at a distance above the light-dark boundary. As a result, sufficient lighting high-mounted traffic signs and signs is achieved. In the known headlight, the reflection element is arranged in the beam path of the light reflected by the reflector light beam near the optical axis and through this part of the reflected light from the reflector beam is deflected by reflection such that it illuminates the at least one area above the light-dark boundary. The reflection element thus uses light reflected directly by the reflector, wherein it is difficult to arrange the reflection element in such a way that the beam path of the light beam reflected by the reflector is not adversely affected by it. Due to the light beam emitted by the headlight, under certain circumstances an area in the low to medium distance in front of the vehicle is strongly illuminated, which is disadvantageous for the orientation of the vehicle driver.

From the DE 198 60 669 A1 is a projection vehicle headlamp with a arranged above the optical axis shielding device and an additional reflector known. The shielding device reduces the illumination intensity in the vehicle apron. The auxiliary reflector reflects shaded light from the shielding device past the lens of the projection system onto the road.

From the US 5,307,247 A is a vehicle headlamp with a arranged between the aperture and lens reflection element is known, which serves to illuminate a region above the light-dark boundary.

Advantages of the invention

The headlight according to the invention with the features according to claim 1 has the advantage that a reduction of the illuminance in low to medium distance in front of the vehicle is made possible by the shield, whereby the eyes of the driver better adapted to the far range just below the light-dark boundary in front of the vehicle and the orientation of the driver is improved.

Another advantage is that light is used for illumination above the light-dark boundary by means of the shielding element, which would otherwise not pass through the lens. It is also advantageous that the beam path of the light beam reflected by the reflector is not adversely affected.

drawing

An embodiment of the invention is illustrated in the drawing and explained in more detail in the following description. Show it 1 a headlamp in a vertical longitudinal section, 2 the headlamp in a cross section along line II-II in 1 and 3 a measuring screen arranged at a distance in front of the headlight when illuminated by the light emitted by the headlight.

Description of the embodiment

One in the 1 and 2 illustrated headlights for vehicles, especially motor vehicles, is constructed according to the projection principle. The headlight is used to generate a dimmed light beam, in particular a low beam. The headlight has a reflector 10 on, for example, has an ellipsoidal or ellipsoidal shape. The reflector 10 has an opening in its apex area 12 on, in which a light source 14 is used. The light source 14 may be an incandescent lamp or a gas discharge lamp and accordingly has an incandescent filament or an arc as a luminous element 16 on. The luminous body 16 the light source 14 is approximately in the range of the inner focus of the reflector 10 on the optical axis 11 of the reflector 10 arranged. Through the reflector 10 is from the light source 14 reflected light as a converging light beam.

In the beam path of the reflector 10 reflected light beam is a diaphragm 18 arranged, extending below the optical axis 11 extends. The aperture 18 for example, in the region of the outer focus of the reflector 10 lie. The aperture 18 can in this case approximately in the plane of the light exit direction 13 pointing front edge of the reflector 10 be arranged. Through the aperture 18 becomes part of the reflector 10 shielded light beam, while another part of the light beam at the aperture 18 past arrives. The at the aperture 18 Passing light beam has a through the top edge 20 the aperture 18 certain chiaroscuro limit. In light exit direction 13 after the aperture 18 is a lens 26 arranged through which the top edge 20 the aperture 18 is shown as the light-dark boundary of the light beam emerging from the headlight. The Lens 26 can be made of glass or plastic. The Lens 26 is designed as a converging lens and has, for example, an opposite light exit direction 13 pointing at least approximately flat inside 27 and one in the light exit direction 13 facing convex curved outside 28 on. The convex curved outside 28 the lens 26 preferably has an aspherical curvature and may also be divided into a plurality of different curved segments. The inside 27 the lens 26 may also be formed concave or convex curved. The Lens 26 is in a tubular support element 30 at the light exit direction 13 held end portion, wherein the support element 30 in its opposite light exit direction 13 pointing end area on the reflector 10 , in particular at its front edge, is attached. The aperture 18 can together with the carrier element 30 at the reflector 10 be attached.

In 2 the headlight is shown in a cross section. The top edge 20 the aperture 18 has different sections 21 . 22 on, which is approximately in one the optical axis 11 containing vertical center plane 23 to meet. The illustrated embodiment of the headlamp is provided for right-hand traffic, so that in front of the vehicle, the own traffic side is right and the oncoming traffic is on the left. The sections 21 . 22 the top edge 20 the aperture 18 are arranged such that the light-dark boundary is located higher on the own traffic side in front of the vehicle than on the oncoming traffic side. For example, the section runs 21 the top edge 20 the aperture 18 at least approximately horizontal and at the level of the optical axis 11 containing horizontal center plane 24 , The section 22 runs, for example, starting from the vertical center plane 23 inclined downwards. The angle under which the section 22 to the horizontal median plane 24 is inclined, is preferably about 15 °. The top edge 20 the aperture 18 is through the lens 26 mapped vertically and horizontally, so that the section 21 forming a horizontal chiaroscuro boundary section on the oncoming traffic side and the section 22 forms a rising chiaroscuro border section on the own traffic side. The light-dark boundary of the light beam emerging from the headlight thus has a course as prescribed in European regulations. Alternatively, the section 22 the top edge 20 the aperture 18 as in 2 indicated by dashed line also at least approximately horizontal and deeper than the section 21 run, with the two sections 21 . 22 are interconnected by a vertical or inclined intermediate portion.

In 3 is a spaced from the headlight arranged screen 80 represented, which is illuminated by the light emitted by the headlight. The measuring screen 80 represents the projection of a lane in front of the headlight, which would be illuminated accordingly. The horizontal center plane of the measuring screen 80 is labeled HH and the vertical midplane is labeled VV. The horizontal center plane HH and the vertical center plane VV intersect at a point HV. That of the reflector 10 reflected, at the aperture 18 passing by, through the lens 26 passing and emerging from the headlight light illuminates the screen 80 in one area 82 , The area 82 is bounded at the top by the light-dark border, by the top edge 20 the aperture 18 is produced. The light-dark border has a horizontal section on the oncoming traffic side 83 on that through the section 21 the top edge 20 the aperture 18 is produced. On the own traffic side, the light-dark border has a rising section 84 on that through the section 22 the top edge 20 the aperture 18 is produced. The distribution of illuminance in the area 82 is through several lines 85 same illuminance illustrated. In the area 82 is in a zone 86 just below the light-dark border 83 . 84 and slightly to the right of the vertical mid-plane VV the highest illuminance exists. Above the light-dark border 83 . 84 becomes the measuring screen 80 through the at the top 20 the aperture 18 Passing light is not or only very weakly lit. The sharpness of the image of the top edge 20 the aperture 18 as a light-dark border 83 . 84 depends, among other things, on the imaging properties of the lens 26 , It is beneficial to the light-dark border 83 . 84 with a certain blur to avoid too much contrast that could be annoying.

According to the invention is between the aperture 18 and the lens 26 at least one shielding element 40 arranged partially in the beam path of the reflector 10 reflected and at the aperture 18 passing light beam protrudes, so that through the shield 40 a part of the light beam is shielded. The shielding element 40 is far below the optical axis 11 arranged and can for example in a lower peripheral region of the support element 30 held or formed integrally with this. Through the shielding element 40 a part of the light beam is partially shielded, which would cause a light to medium distance in front of the vehicle. In 3 is a zone 88 marked by the shielding element 40 partially shielded part of emerging from the headlight beam would be illuminated. By the partial shielding of the light beam by the shielding element 40 the illuminance will be in the zone 88 reduced. This is advantageous because with a lighting of the zone 88 With high illuminance, the driver's eyes would adapt too much to areas in the low to medium range in front of the vehicle and thus the far-range just below the light-dark boundary 83 . 84 subjectively perceived as dimly lit. With reduced illuminance in the zone 88 adapt the eyes of the driver to the far range just below the light-dark limit 83 . 84 , whereby the orientation of the driver is improved.

The shielding element 40 is preferably arranged such that its edges through the lens 26 not be sharply imaged to ensure a smooth transition between the zone 88 and the rest of the area 82 without a strong change in illuminance. The shielding element 40 For example, as in 2 illustrated have an approximately rectangular shape or any other shape. The arrangement, size and shape of the shield 40 will depend on the required location, size and lighting distribution of the area 90 and the required location, size and reduction in illuminance in the zone 88 certainly.

To provide sufficient illumination above the light-dark limit 83 . 84 can be provided that the shielding 40 on his the lens 26 facing, in the light exit direction 13 facing side a reflection surface 42 having. The shielding element 40 may for example consist of sheet metal. That of the reflector 10 reflected and at the aperture 18 Passing light beam passes for the most part through the lens 26 but also a small proportion of the light beam on the inside 27 the lens 26 is reflected and not through the lens 26 passes. Part of the inside 27 the lens 26 reflected light hits the reflection surface 42 the shielding element 40 and is reflected by them in such a way that it passes through the lens 26 passes and above the light-dark border 83 . 84 of the reflector 10 reflected, at the aperture 18 passing and through the lens 26 passes through the light beam. The Lens 26 can on their inside 27 at least in some areas with a coating 29 be provided, which is partially reflective and partially translucent. Through the coating 29 can be achieved that on the inside 27 the lens 26 a higher proportion of light is reflected by the shielding 40 can be used as without coating. Through the coating 29 can be a warming of the lens 26 and / or in the light exit direction 13 after the lens 26 arranged cover plate 31 be reduced, which is particularly advantageous when the lens 26 and / or the cover 31 made of plastic.

That of the shielding element 40 reflected through the lens 26 passing and emerging from the headlight light illuminated on the screen 80 at least one in 3 shown area 90 , The area 90 is preferably at a distance h above the light-dark boundary 83 . 84 arranged so that between the areas 82 and 90 a zone with very low illuminance is present, to avoid dazzling oncoming vehicle driver safely. However, higher elevation traffic signs or signs located in the area 90 lie, sufficiently lit. The location, shape and distribution of illuminance in the area 90 is dependent on the arrangement, that is the position of the shielding 40 or from its reflection surface 42 in the direction of the optical axis 11 and perpendicular to this and the inclination of the shielding 40 , In addition, the shape and distribution of illuminance are in the range 90 depending on the size and shape of the shielding element 40 or its reflection surface 42 , The larger the shielding element 40 is, the more light is detected and reflected by this, so that the area 90 can be larger and the illuminance in the area 90 can be higher. The reflection surface 42 the shielding element 40 may be at least approximately flat or curved concave or convex. With a concave curvature of the reflection surface 42 the shielding element 40 can be a concentration of light reflected by this in the field 90 be achieved with a correspondingly high illuminance. Due to the non-directional light reflection on the flat side 27 the lens 26 generally also takes place through the reflection surface 42 the shielding element 40 no directed light reflection but a scattered light reflection, so that in the area 90 a uniform distribution of illuminance without pronounced maximum is present.

Claims (1)

Vehicle headlight according to the projection principle with a light source ( 14 ), with a reflector ( 10 ), by the light source ( 14 ) emitted light is reflected as a converging light beam, with one in the beam path of the reflector ( 10 ) reflected light beam arranged aperture ( 18 ), by which a part of the light beam is shielded, with a in the light exit direction ( 13 ) after the aperture ( 18 ) arranged lens ( 26 ), by the one upper edge ( 20 ) the aperture ( 18 ) as a light-dark border ( 83 . 84 ) of the light beam emerging from the headlight, whereby between the diaphragm ( 18 ) and the lens ( 26 ) at least one shielding element ( 40 ) at a distance below the optical axis ( 11 ) is arranged partially in the beam path of the reflector ( 10 ) reflected light bundle, characterized in that the shielding element ( 40 ) is arranged so that it is part of the reflector ( 10 ) partially shields the reflected light beam, which would cause illumination at a short to medium distance in front of the vehicle, and that on its lens ( 26 ), in the light exit direction ( 13 ) facing side a reflection surface ( 42 ), which forms a part of the inner side facing towards the light exit direction ( 27 ) of the lens ( 26 ) reflected light so that it passes through the lens ( 26 ) and above the light-dark boundary ( 83 . 84 ) of the reflector ( 10 ), at the aperture ( 18 passing and passing through the lens ( 26 ) passes through light beam passes.

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