Koito Manufacturing Company, Ltd.

Koito Seisakusho Co., Ltd.

Naohi Nino

Akinori Matsumoto

Shinji Kagiyama

Tomoyuki Moritani

Takayuki Iwaki

Takeshi Arai

A vehicle headlamp includes a projection lens which is placed on an optical axis extending in a front and rear direction of a vehicle, a light source which is placed behind a rear focal point of the projection lens, a reflector which reflects light emanated directly from the light source in a forward direction and toward the optical axis, and a light-dark boundary forming plate which is placed between the projection lens and the light source. The light-dark boundary forming plate extends rearward and obliquely downward from a vicinity of the rear focal point of the projection lens, and a light-dark boundary forming portion is formed on a front end portion of the light-dark boundary forming plate. The light-dark boundary forming portion shields a part of the light reflected from the reflector and forms a cut-off line of a light distribution pattern.

Vehicle headlamp

A reflecting mirror, for a vehicle headlamp, which provides a sufficient amount of light near a slant cutoff line in downward-beam light distribution, thereby improving visibility in a long-distance region and a medium-distance region. The reflecting mirror has at least a first reflecting area and a second reflecting area. For a first reflecting area ( B&mdash;close to a horizontal reference face (x-y plane) when a reflecting face ( ) is viewed from an optical axis direction&mdash;a reference curve is set in a slant reference face inclined to the horizontal reference face at an angle equal to an angle (&thgr;col) of a slant cutoff line with a horizontal line. For a second reflecting area ( D, E)&mdash;positioned above or below the first reflecting area ( B) with respect to the horizontal reference face&mdash;a reference curve is set in a slant reference face inclined to the horizontal reference face at a second angle larger than 0&deg; and smaller than the angle of the slant cutoff line with the horizontal line. Parabolas are then associated with planes orthogonal to the slant reference face, thereby forming a curved surface.

Vehicle head lamp and method of forming a reflecting mirror therefor

In the formation of a basic surface of a reflection surface of a reflection mirror for a vehicle lamp, when a reference curve is established on a horizontal surface containing the optical axis or on an inclined surface inclined with respect to the horizontal surface, a light source, the central axis of which extends along the optical axis, is arranged close to the reference point of the reference curve. Then the reference curve is composed when a hyperbolic portion having a focus on the optical axis and an elliptical portion also having a focus on the optical axis are repeatedly arranged in a direction separate from the optical axis, and an angle of the reflecting light, which has been emitted from the light source, with respect to the optical axis at a point on each curve portion of the reference curve, is determined in such a manner that the closer to the optical axis the curve portion is, the larger the angle is increased. An imaginary paraboloid of revolution is assumed, the axis of which is parallel with the light vector of the reflecting light that has been sent from the reference point on the reference curve and reflected at an arbitrary point on the reference curve, and the imaginary paraboloid of revolution passes through the reflecting point, and its focus is located at the reference point.

Reflection mirror for vehicle lamp and method of forming the same

A reflection surface is divided into four reflection areas by means of a horizontal surface, a vertical surface and a surface inclined with respect to the horizontal surface, the three surfaces respectively including the optical axis of the reflector. The four reflection areas include a basic surface. The basic surface is an aggregate (envelope surface) of intersection lines obtained when a virtual paraboloid of revolution, which includes a reference parabola in the horizontal surface or inclined surface and has as a focus (second focus) a point on an optical axis passing through the vertex and focus of the reference parabola and situated in front of or to the rear of a focus (first focus) with respect to the vertex, is cut by vertical surfaces respectively including the optical axis. The focal positions of the sections (parabolas) in the adjoining reflection areas are made to coincide with one another to make the boundaries of the reflected areas continuous with one another, and also the positional relation between a filament and the first and second focuses of each of the reflection areas is controlled.

Reflector for vehicular headlight

A reflecting surface is divided into first and second reflecting sectors by a plane inclined from the horizontal plane including the optical axis to occupy the upper half and the lower half of the reflecting surface, respectively. A fundamental surface of the first and second reflecting sectors has a reference parabola in the inclined plane, and is a collection of intersecting lines each obtained by cutting an imaginary paraboloid of revolution having an axis extending in a direction taken by a ray after being emitted from a reference point and then reflected at a reflecting point on a parabola that is an orthogonal projection of the reference parabola onto the horizontal plane, passing through the reflecting point, and having a focus at the reference point by a vertical plane including the ray vector. The focus of the reference parabola is set at the center of a filament. The reference point is set in the vicinity of the rear end of the filament for the first reflecting sector, and in the vicinity of the front end of the filament for the second reflecting sector.

Vehicular low beam headlight reflector consisting of upper and lower

The xyz orthogonal coordinate system is set so that the x-axis coincides with the optical axis of a reflecting surface. A fundamental surface has a reference point on the x-axis and a reference parabola included in a plane inclined, in a generalized form, from the xy-plane and having a vertex on the origin of the coordinate system and a focus on the x-axis in the rear of the reference point. The fundamental surface is a collection of intersecting lines each obtained by cutting an imaginary paraboloid of revolution having an axis extending in parallel with a ray vector direction taken by a reflected ray after being emitted from the reference point and then reflected at a reflecting point on a parabola that is an orthogonal projection of the reference parabola onto the xy-plane, passing through the reflecting point, and having a focus at the reference point by a plane in parallel with the z-axis and including the ray vector. The reflecting surface is formed by periodically arranging identical sectors of the number of apices of an intended stellate light distribution pattern around the optical axis. Each sector has a shape of a generally fan-shaped portion of the fundamental surface having a central angle of 360.degree. divided by the number of apices of the stellate pattern and located in the vicinity of the xy-plane or xz-plane.

Reflector for illumination lamp capable of producing a stellate light

A vehicular headlight reflector for forming a low beam light-distribution pattern by effectively utilizing the entire reflecting surface, and providing a light-distribution control function so that a pattern image generated substantially by a lower half surface of the reflector is located below the horizontal line and as close to the horizontal line as possible. A filament is arranged between a focus F of a reference parabola and a reference point D offset from the focus F so that its central axis extends in parallel with an axis passing through the parabola vertex O and the reference point D. A virtual paraboloid is assumed for each arbitrary point P on the reference parabola, the virtual paraboloid having an optical axis that extends in parallel with a light ray vector of a reflected light ray obtained when a light ray assumed to have been emitted from the reference point D and reflected at the point P, passing through the point P, and having the point D as its focus. A reflecting surface is formed as a collection of intersecting lines obtained when the virtual paraboloid is cut by a plane including the light ray vector and being parallel with the vertical axis (z-axis). Projected images of the light source are located so as to move around a rotation center on the horizontal line with a movement of representative points on an intersecting line in the reflecting surface.

A reflecting surface consists of three reflecting sectors arranged around the optical axis. The first reflecting sector located above the horizontal plane including the optical axis is a part of a paraboloid of revolution having a focus at point F. The second reflecting sector consists of two sub-sectors located on the right and left sides of the vertical plane including the optical axis. A fundamental surface of the two sub-sectors has a reference parabola in a plane inclined from the horizontal plane by a predetermined angle, and is a collection of intersecting lines each obtained by cutting an imaginary paraboloid of revolution assumed for a point on an orthogonal projection of the reference parabola onto the horizontal plane by a vertical plane including an axis of the imaginary paraboloid of revolution. The third reflecting sector located below the horizontal plane is a part of a paraboloid of revolution having a focus at point G. An orthogonal projection of an arc of a discharge lamp is located between points F and G.

Vehicular headlight reflector suitable for use with a discharge lamp

An automotive projector type headlight including a light source, a reflector for reflecting the light forward, a shade for partially shading and thus contouring the reflected light, and a projecting lens for projecting the contoured light forward. The light source comprises a main filament and a sub-filament extending generally along the optical axis. The reflector has a plurality of radially divided reflective surface portions. An upper reflective surface portion reflects the light from the sub-filament and converge it to a first converging position located above the optical axis. A shading edge of the shade is positioned near to the first converging position. The projecting lens has a focus near to the shading edge. A lower reflective surface portion reflects the light from the main filament, converges it to a second converging position extending horizontally and converges the light to a third converging position extending vertically. Left and right reflective surface portions act to converge the light from both filaments and to diffuse it thereafter. And a portion of the reflective surface is formed into paraboloid of rotation having the focus near to the filaments.

Automotive projector type headlight

Disclosued herein is a headlamp unit. The unit comprises a multi-surface concave reflector having a beam axis along which a light beam projects forward to produce a beam pattern, the reflector including upper and lower concave light reflecting parts which are respectively located at upper and lower positions with respect to a given portion of the reflector, and left and right concave light reflecting parts which are respectively located at left and right positions with respect to the given portion and have respective focuses on their respective optical axes, the optical axes being inclined with respect to the beam axis, each of the left and right concave light reflecting parts having respective curves of second degree when cut by vertical and horizontal planes; and first and second filaments of an electric bulb which are located on the beam axis. The optical axes of the left and right concave light reflecting parts are inclined toward the left and right concave light reflecting parts with respect to the beam axis, respectively, and the focuses of the left and right concave light reflecting parts are located at generally right and left positions with respect to the first filament, respectively.

Headlamp unit

Disclosed herein is a vehicular headlamp, which comprises a compound light reflector having a concave light reflecting surface which consists of upper, lower, left and right triangular parts which are radially arranged about a given portion of the reflector. The upper and lower parts have a substantially common focus and are so arranged that when light rays are emitted from the position of the common focus, the upper and lower parts reflect the light rays forward to form a horizontal focal line before the common focus. Each of the left and right parts is so shaped and arranged that when cut by a horizontal plane, it shows an elliptic line along the cut edge, and when cut by a vertical plane, it shows a parabolic line along the cut edge. The upper, lower, left and right parts are so arranged as to have their focuses positioned at generally same position. A light source is positioned at the common focus, and a converging lens is positioned in front of the horizontal focal line and arranged in such a manner that a focus of the converging lens is positioned in the vicinity of the horizontal focal line. If desired, a shading plate may be employed. In this case, the shading plate is arranged in the vicinity of the horizontal focal line.

Vehicular headlamp

A headlight having a reflector with the optical axis thereof being inclined relative to the optical axis of the headlight, a light source provided on a focus of the reflector and on the optical axis thereof, a projector lens in front of the reflector, and a shade plate provided nearly on a focus of the projector lens. The reflective surface of the reflector is formed to reflect the light emitted from the light source and to converge the reflected light into a curved line on a plane parallel to a plane including the optical axis of the headlight.

Headlight device for vehicle

Herein disclosed is a vehicle headlamp which comprises a compound light reflector including a plurality of concave light reflecting surfaces which are arranged to have a first common focus, either one of a second common focus and a second common focal line, and a common optical axis, each light reflecting surface being so shaped as to provide an elliptical line when cut by a vertical plane; a light source located on the first common focus of the compound light reflector; a shade plate positioned in front of the compound light reflector, the shade plate having an upper edge located in the vicinity of one of the second common focus and the second common focal line; and a converging lens located in front of the shade plate in such a manner that a focus of the lens is positioned on the upper edge of the shade plate.

A headlight device comprising a reflective mirror having a reflective zone consisting of a plurality of reflective elements, and a light source arranged along an axis of irradiation which extends in the fore and aft direction of the reflective mirror. The reflective elements constituting the reflective zone are formed to have parabola-ellipse composite surfaces. The composite surface is defined to have a parabola in the vertical section and an ellipse in the horizontal section.

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Shizuoka, Japan

Naohi Nino