Illumination – Supported by vehicle structure – Light modifier
Reexamination Certificate
2002-04-23
2003-10-21
O'Shea, Sandra (Department: 2875)
Illumination
Supported by vehicle structure
Light modifier
C362S294000, C362S293000, C362S516000, C362S539000, C362S464000, C362S465000, C362S466000
Reexamination Certificate
active
06634776
ABSTRACT:
BACKGROUND OF THE INVENTION
1.Field of the Invention
The present invention relates to an infrared irradiation lamp for an automobile which is mounted on an automobile and illuminates a forward portion of a vehicle with an infrared light, and more particularly to an infrared irradiation lamp for an automobile which has such a structure that an infrared light is formed by a globe for infrared light formation covering a bulb to be a light source and which is shared with a CCD camera having a sensitivity up to a near-infrared.
2.Description of the Related Art
For example, this kind of lamp has such a structure that a visible light source and a reflector are provided in a lamp housing formed by a lamp body and a front lens, an infrared light transmission globe having a surface coated with an infrared light transmission multilayer film is provided to cover the visible light source, and an infrared light in a light of a light source which is transmitted through a globe is reflected by the reflector, is transmitted through the front lens and is distributed forward.
An infrared light irradiation region in a forward portion of a vehicle is photographed by a CCD camera having a sensitivity up to a near-infrared which is provided in a front part of an automobile, is processed by an image processing apparatus and is projected onto a monitor screen in a vehicle compartment. A driver can confirm a person, a lane mark and an obstacle over the monitor screen projecting a field of view in the forward part of the vehicle at a great distance.
In the conventional infrared irradiation lamp, however, a halogen bulb to be a visible light source is surrounded by the infrared light transmission globe. Therefore, the inside of the globe is filled with heat generated from the bulb so that the inside of the globe has a high temperature. For this reason, there is a problem in that the halogen cycle of the halogen bulb does not function so that the lifetime of the bulb or the infrared light transmission globe is shortened, for example, blacking is generated to decrease an amount of a light or the infrared light transmission multilayer film of the globe is deteriorated to degrade an infrared ray cut characteristic.
Further, an infrared light transmission multilayer film cannot completely cut a visible light on the long-wavelength side of approximately 700 to 800 nm. Therefore, the lamp is seen to be turned on. For this reason, there is a possibility that the infrared irradiation lamp provided in the front part of an automobile might be erroneously recognized as a tail lamp or a stop lamp. Therefore, there is a problem in respect of safety.
Secondly, a halogen cycle does not function in a halogen bulb to be a visible light source. Consequently, there is a problem in that the lifetime of a light source or an infrared light transmission globe is shortened, for example, blacking is generated to decrease the amount of a light or the infrared light transmission multilayer film might be deteriorated to degrade an infrared ray cut characteristic.
The inventor made investigations for these causes. As a result, referring to the first problem, the red light component of the visible light which cannot completely be cut by the infrared light transmission globe (the visible light transmitted through the infrared light transmission globe) is guided to the whole reflector and a light reflected in a peripheral region of a light source in the reflector and emitted from the vicinity of the central part of a front lens has the highest energy (luminous flux density). Therefore, it has been confirmed that the vicinity of the central part of the front lens (the peripheral region of the light source in the reflector) is seen to emit a red light to be ring-shaped.
Referring to the second problem, moreover, the conventional infrared light transmission globe has a rear end thereof provided to abut on the reflector. Therefore, it has been confirmed that the inside of the infrared light transmission globe is filled with heat generated from a halogen bulb to be a visible light source, for example, and the lifetime of the light source or the infrared light transmission globe is thereby reduced, that is, blocking is generated to decrease the amount of the light and the infrared light transmission multilayer film is thermally degraded.
Therefore, the inventor supposed that the red light component of the visible light to be the cause of the lamp to be seen red is preferably diluted. Consequently, a clearance is provided between the rear end of the infrared light transmission globe and the reflector to directly guide a part of the light of the light source from the clearance to the peripheral region of the light source in the reflector. Thus, it has been confirmed that an advantage can be obtained in order to reduce a tone of red color for light emission of the lamp, and furthermore, the inside of the infrared light transmission globe is not filled with heat. Thus, the invention has been proposed.
The invention has been made based on the problems of the prior art and the knowledge of the inventor and has an object to provide an infrared irradiation lamp in which a clearance is provided between an infrared light transmission globe and a reflector so that the turn-on of a lamp is not erroneously recognized as a tail lamp or a stop lamp, and furthermore, the inside of the infrared light transmission globe is not filled with heat.
SUMMARY OF THE INVENTION
The invention has been made in consideration of the problems in the prior art and has an object to provide an infrared irradiation lamp in which the inside of a globe for infrared light formation is not filled with heat.
In order to achieve the object, a first aspect of the invention is directed to an infrared irradiation lamp for an automobile comprising a lamp housing formed by a lamp body and a front lens, a reflector provided in the lamp body, a light source provided ahead of the reflector in the lamp housing, and a cylindrical globe for infrared light formation which is provided to cover the light source and serves to shield a visible light and to transmit only an infrared light,
wherein the globe for infrared light formation has a rear end thereof provided apart from the reflector, and a light of the light source is directly guided from a clearance provided between the reflector and the rear end of the globe for infrared light formation to a peripheral region of the light source in the reflector.
The light distribution of the lamp includes the case in which a step for light distribution control is not provided on the front lens but the light is controlled and formed by only the reflector in addition to the case in which the light reflected by the reflector is controlled and formed at the step for light distribution control provided on the front lens. It is assumed that the front lens also includes the front lens having no step for light distribution control, that is, a so-called front cover. (Function)
The red light component of the visible light which cannot be completely cut by the globe for infrared light formation (the visible light transmitted through the globe for infrared light formation) is reflected by the whole reflector and is emitted from the front lens. A light reflected by the peripheral region of the light source in the reflector and emitted from the vicinity of the central part of the front lens corresponding to the peripheral region of the light source has the highest energy (luminous flux density). For this reason, conventionally, the vicinity of the central part of the front lens (the region corresponding to the peripheral region of the light source in the reflector) is seen to emit a light like a red ring. In the first aspect of the invention, a part of the light of the light source (the light of the light source which is not transmitted through the globe for infrared light formation) is directly guided from the clearance provided between the reflector and the rear end of the globe for infrared light formation toward the inside of the peripheral region of the light sou
Hori Takashi
Inoue Takashi
Yagi Seiichiro
Koito Manufacturing Co. Ltd.
O'Shea Sandra
Sughrue & Mion, PLLC
Tsidulko Mark
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