Patent Application
20080037268
Embodiments of an infrared light irradiating lamp for a vehicle according to the invention will be described below in detail with reference to the accompanying drawings. Like items in the figures are shown with the same reference numbers. In this application, a longitudinal direction of the vehicle is the direction in which a vehicle incorporating the infrared light irradiating lamp would travel, and front and forward denote a forward direction of travel of the vehicle, while behind and rear denote a backward direction of travel of the vehicle. A vertical direction is a direction perpendicular to a ground plane of the vehicle. A longitudinal direction of a filament is a direction in which the filament has the greatest length.
An infrared light irradiating lamp 100 for a vehicle according to the first embodiment is used in a night forward visual field detecting system and is provided in a front portion of a vehicle to irradiate an infrared light onto a forward part of the vehicle, for example. The night forward visual field detecting system is constituted by the infrared light irradiating lamp 100 for a vehicle shown in
Images of invisible distant pedestrians, obstacles, or lane marks which are photographed by the CCD camera are sent to the image processing analyzing apparatus. By carrying out an edge processing or a pattern recognition from the images, it is possible to easily recognize the pedestrians, the obstacles, and the lane marks.
The images of the pedestrians, the obstacles, and the lane marks can be given to a driver through the head up display (HUD), and can decide the features of the objects on a road (the pedestrians, the obstacles, and the lane marks) through a shape recognition, thereby giving a notice to the driver in a voice.
The infrared light irradiating lamp 100 for a vehicle is constituted by a lamp body 21 formed of a synthetic resin which has a front side opened and takes a shape of a vessel, a transparent front cover 23 assembled into the front opening portion of the lamp body 21 and serving to partition and form a lighting chamber S in cooperation with the lamp body 21, and a projection type light source unit 25 accommodated in the lighting chamber S and supported to be regulated tiltably in vertical and transverse directions by means of an aiming mechanism which is not shown.
As shown in
The projection type light source unit 25 has such a structure that the filament 27a of the light source bulb 27 is positioned on a first focal point f1 of the reflecting plane 29a in the reflector 29 and a second focal point f2 of the reflecting plane 29a is positioned in the vicinity of a rear focal point of the convex lens 33 so that a light of the light source which is reflected by the reflecting plane 29a to be an effective reflecting plane subjected to an aluminum evaporation treatment in the reflector 29 is changed into an almost parallel light L1 through the convex lens 33 and is thus projected and distributed. More specifically, a light distribution pattern created by the projection type light source unit 25 is the same as that of a headlamp of a car for forming a main beam.
Furthermore, an infrared light transmitting filter 35 is provided between the reflector 29 and the convex lens 33, that is, on a rear end side of the lens holder 31.
In the infrared light transmitting film 35, an infrared light transmitting film 35a for reflecting a visible light component and transmitting an infrared light component is formed circularly on a back face of a glass plate 35b. The infrared light transmitting film 35a is disposed in the vicinity of the focal point f2 of the reflector reflecting plane 29a in the reflector 29.
The projection type light source unit 25 according to the embodiment has such a structure that the infrared light transmitting filter 35 is singly disposed between the convex lens 33 and the reflector 29 so that the infrared light transmitting filter 35 can easily be exchanged. By disposing the infrared light transmitting film 35a in the vicinity of the second focal point f2 in the proximity of a light collecting portion, moreover, it is possible to reduce a size (a diameter) of the infrared light transmitting film 35a.
The lens holder 31 is formed by the same aluminum die casting as the reflector 29, and a front edge portion thereof is circumferentially provided with a lens engaging portion 37 taking a shape of an inner flange with which a peripheral flange portion 33a of the convex lens 33 can be engaged.
A lens holding frame 39 formed of a metal and taking a shape of a circular ring is fixed to the front edge portion of the lens holder 31, and the peripheral flange portion 33a of the convex lens 33 is fixed and held in an engaging state with the lens engaging portion 37. In the lens holder 31 and the reflector 29, coupling flange portions 41 and 43 are bonded to each other by bonding means which is not shown, for example, a screw.
The light source bulb 27 of the projection type light source unit 25 is attached to an attaching opening portion 45 provided on a side of the reflector 29 and is inserted and fixed into the reflector 29 from the side of the optical axis Ax as shown in
According to the infrared light irradiating lamp 100 for a vehicle in accordance with one or more embodiments, a light irregularity 47 of a filament image of the light source bulb 27 is generated to be extended in such a direction as to cross the white line 17 on the road surface as shown in
In the detection of the white line through an infrared CCD camera in an image processing analyzing apparatus, consequently, the light irregularity 47 is hard to erroneously detect as the white line 17. Thus, it is possible to considerably enhance precision in the detection of the white line.
By transversely inserting the light source bulb 27, moreover, the protrusion from the rear portion of the lamp body 21 is reduced more greatly than that in the conventional rear inserting structure. Consequently, it is possible to reduce the overall length of the lamp unit.
By transversely inserting the light source bulb 27, furthermore, the filament 27a of the light source bulb 27 is extended in a transverse direction. Consequently, it is possible to form a wide hot zone in which an irradiated light is enlarged in the transverse direction. By the detection of the white line, it is possible to carry out an advantageous infrared light irradiation.
While the infrared light transmitting filter 35 having the infrared light transmitting film 35a is independently disposed between the convex lens 33 and the reflector 29 in the embodiment, the infrared light transmitting film 35a may be disposed on the back face of the convex lens 33 as shown in
With the structure, by disposing the infrared light transmitting film 35a on the back face of the convex lens 33, it is not necessary to employ a filter structure in the case in which the infrared light transmitting filter 35 is disposed as a single member. Consequently, the number of components can be decreased and a lamp structure can be simplified. As compared with the case in which the infrared light transmitting filter 35 is disposed in the vicinity of the focal length, it is possible to transmit a light having a comparatively low light density. Thus, it is possible to lessen a thermal influence for the infrared light transmitting film 35a.
While the first focal point f1 and the second focal point f2 are placed in positions apart from each other in the reflector reflecting plane 29a taking an almost elliptical spherical shape in the embodiment, moreover, this is not restricted but the first focal point and the second focal point may be almost coincident with each other, that is, a spherical reflector reflecting plane may be employed.
Next, description will be given to an infrared light irradiating lamp for a vehicle according to a second embodiment of the invention.
In the same manner as the infrared light irradiating lamp 100 for a vehicle according to the first embodiment, the infrared light irradiating lamp for a vehicle according to the second embodiment is constituted by a lamp body 21 formed of a synthetic resin, a transparent front cover 23 for partitioning a lighting chamber S in cooperation with the lamp body 21, and a projection type light source unit 51 supported to be regulated tiltably in vertical and transverse directions by an aiming mechanism, which is not shown.
As shown in
The filter driving unit 73 has such a structure that a filter bracket (a movable member) 83 can displace an infrared light transmitting filter 85 held in the filter bracket 83 between a position in which a light reflected by the reflector 53 is intercepted and a position in which the reflected light is not intercepted by means of an electric type reciprocating actuator 70.
More specifically, the infrared light transmitting filter 85 is supported on one of rotating ends of a support portion 79, which is rotatable around a horizontal shaft 81, and a plunger 87 of the reciprocating actuator 70 is linked to the other rotating end. When the plunger 87 carries out a vertical operation, the filter bracket 83 is rocked.
When the filter bracket 83 is disposed in the position in which the light reflected by the reflector 53 is intercepted, the light emitted from the light source bulb 67 is transmitted through the infrared light transmitting filter 85 so that the light can be used as an infrared light irradiating lamp. On the other hand, when the filter bracket 83 is disposed in the position in which the light reflected by the reflector 53 is not intercepted, the light emitted from the light source bulb 67 is irradiated as a direct visible light and can be used as a normal headlight.
In other words, according to the infrared light irradiating lamp in accordance with the embodiment, one lamp can be caused to function as two different lamp units, that is, an infrared light irradiating lamp and a normal illuminating lamp.
In the projection type light source unit 51 related to the infrared light irradiating lamp for a vehicle in accordance with the second embodiment, as shown in
More specifically, with the conventional structure in which the light source bulb 9 is disposed on the optical axis as shown in
On the other hand, when the light source bulb 67 is inserted apart into the lower side of the optical axis Ax as in one or more embodiments of the present invention, it is possible to maintain a larger reflector reflecting plane 53a, which is continuous from the lower side of the optical axis Ax to the upper side thereof, as compared with the case in which the reflector reflecting plane is vertically divided into two parts for use. Consequently, it is possible to minimize a waste of the light reflected by the reflecting plane on the lower side when the shielding member such as the shade or the filter driving unit 73 is present on the lower side of the optical axis Ax, for example. Thus, it is possible to enhance the light utilization efficiency.
The infrared light transmitting filter 85 is obtained by depositing, on a glass plate 85b, an infrared light transmitting film 85a for reflecting a visible light component and transmitting an infrared light component as shown in
Moreover, a diffusing portion 91 is formed to have a V-groove-shaped section which is extended vertically on a surface at an opposite side of the reflector 53, that is, a surface of the glass plate 85b which is opposed to a back face of the convex lens 59. The diffusing portion 91 is formed adjacently to the infrared light transmitting film 85a.
According to the infrared light transmitting filter 85 having the diffusing portion 91, it is possible to diffuse an infrared light in a transverse direction by the diffusing portion 91 and to complement a light to be irradiated in a side direction of a vehicle, that is, a pavement or a shoulder of a road.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-217481 | Aug 2006 | JP | national |
