Illumination – Supported by vehicle structure – Light modifier
Reexamination Certificate
1998-12-24
2001-01-30
Quach, Y. (Department: 2875)
Illumination
Supported by vehicle structure
Light modifier
C362S293000
Reexamination Certificate
active
06179456
ABSTRACT:
This application claims the benefit of Japanese patent application No. Hei 9-354981, filed on Dec. 24, 1997 which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to a lamp for use in an outdoor environment. In particular, the invention relates to a headlamp for a vehicle that includes a protective film located on a front lens of the vehicle headlamp and a method for making the vehicle headlamp. The film prevents mist, condensation or other haze from forming on the inside of the lamp chamber while also preventing discoloration of the front lens of the headlamp caused by UV light emitted from a light source located in the headlamp.
2. Discussion of Related Art
Conventional vehicle headlamps often include a lamp body that cooperates with a front lens formed of resin to form a lamp chamber. A discharge lamp bulb located within the lamp chamber acts as a light source. Typical discharge lamp bulbs for vehicle headlamps emit light containing UV light of great energy. This UV light tends to discolor the front lens and, after a period of time, causes the lens to be tinted yellow. In particular, lenses made of polycarbonate (PC) resin are frequently employed for the front lens of vehicle headlamps and are likely to be discolored upon irradiation with UV light.
In many conventional vehicle headlamps, a portion of the inner surface of the lamp body has a reflecting surface that is coated with an UV absorbing film formed of an UV absorbing material. The UV absorbing film prevents discoloration of the front lens.
In addition, many conventional headlamps include a second film or coating on the inner surface of the front lens. The second film or coating can be an anti-haze film formed of an anti-haze material that prevents the lamp chamber from being subjected to mist, condensation or other forms of haze. Examples of materials that can be used for the anti-haze material along with examples of the specific weight ratios and content descriptions of such materials are disclosed in Japanese Laid Open Patent No. 2-255854, which is incorporated herein by reference.
In the aforementioned conventional vehicle headlamp, the UV absorbing film for preventing discoloration of the front lens and the anti-haze film for preventing lamp chamber haze are separately applied to different portions of the inside of the lamp chamber. Therefore, the respective film coating processes have to be conducted separately and individually, which may complicate the overall lamp production process, increase the processing time, and thus result in an increased manufacturing cost.
SUMMARY OF THE INVENTION
Accordingly, the invention is directed to a vehicle lamp, specifically, a vehicle headlamp that includes a protective film which substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
In view of the foregoing, an object of the invention is to overcome the problems of the conventional art by forming a film for preventing both lamp chamber haze caused by mist or condensation, and discoloration of the front lens caused by UV light emitted from the light source. To solve the aforementioned task, a vehicle lamp is provided in which an anti-haze/UV film is prepared by mixing UV absorbing material with anti-haze material. The anti-haze/UV film is coated to the inner surface of the front lens.
Therefore, the vehicle lamp according to the invention eliminates the necessity of applying the anti-haze film and the UV absorbing film individually to different portions within the lamp chamber to prevent lamp chamber haze and discoloration of the front lens caused by condensation and the UV light emitted from the lamp chamber of the lamp, respectively.
According to an aspect of the invention, a lamp is designed for exposure to adverse or outdoor conditions and includes a lamp body defining a lamp chamber and including a front opening. A front lens can be located in the front opening of the lamp body and include an inner surface further defining the lamp chamber. A light source can be located in the light chamber. A film material can be located adjacent to said inner surface of the front lens and include a mix of TV absorbing material and anti-haze material.
According to another aspect of the invention, a method for making a lamp includes providing a lamp housing that includes an opening therein and defines a lamp cavity, providing a lamp lens with an inner surface that cooperates with the lamp housing to further define the lamp cavity, and coating the inner surface of the lamp lens with a coating that contains UV absorption material and anti-haze material.
According to another aspect of the invention, a lamp is designed for exposure to adverse or outdoor conditions and includes a lamp body defining a lamp chamber and including a front opening. A front lens can be located in the front opening of the lamp body and include an inner surface further defining the lamp chamber. A light source can be located in the light chamber. The lamp includes means attached to said front lens for preventing condensation from forming on, and for preventing ultraviolet light rays from contacting said front lens, wherein said means is an integral, unitary structure.
According to another aspect of the invention, a vehicle headlamp can be a projection-type lamp having a projection unit. The projection unit can be formed by joining a projection lens to a front opening of an elliptic reflector disposed in a lamp chamber. Although a projection-type headlamp has great condensing power and tends to discolor the front lens with its high energy UV light, an anti-haze film containing UV absorbing material located on the front lens can prevent such discoloration of the front lens. When the anti-haze film containing UV absorbing material is provided in a projection-type headlamp, the UV absorbing effectiveness can be significantly improved.
According to another aspect of the invention, the anti-haze material can be prepared by retaining a surface active agent in a block copolymer formed of hydrophilic polymer components and hydrophobic polymer components. A benzotriazole material can be used as the UV absorbing material. Accordingly, lens haze can be prevented, good adhesiveness to the lens can be achieved and the film can include high strength characteristics. Because benzotriazole materials are less expensive than material popularly employed for UV absorbing material, for example, zinc oxide, the manufacturing cost of the vehicle headlamp can be reduced.
According to another aspect of the invention, the weight ratio of the UV absorbing material to the anti-haze material is equal to or less than 10%. At this range of weight ratio values the effectiveness of the anti-haze material is acceptable and is capable of preventing lamp chamber haze.
According to another aspect of the invention, the thickness of the anti-haze film is greater than or equal to 1 &mgr;m and less than or equal to 10 &mgr;m. As a result, an excessive increase in the film thickness can be prevented. This selected range for the thickness of the anti-haze/UV film results in an effective anti-haze film and avoids the problems due to excessive film thickness, for example, deteriorated surface smoothness, blooming phenomenon resulting in poor lens appearance, and deteriorated adhesiveness of the film to the lens.
Other objects, features and advantages of the invention will be evident from the following detailed description of the preferred embodiments described in conjunction with the attached drawings. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
REFERENCES:
patent: 4243719 (1981-01-01), Holmes
patent: 5132881 (1992-07-01), Wakimizu et al.
patent: 5134223 (1992-07-01), Langer et al.
patent: 5180218 (1993-01-01), Ohshio
patent: 5180760 (1993-01-01), Oshibe et al.
patent: 5243501 (1993-09-01), Makita et al.
patent: 2-255854 (1990-10-
Aikawa Shinji
Anma Hidetaka
Nakamura Koichi
Warashina Mariko
Koito Manufacturing Co. Ltd.
Morgan & Lewis & Bockius, LLP
Quach Y.
LandOfFree
Vehicle lamp with protective film and method for making same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Vehicle lamp with protective film and method for making same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vehicle lamp with protective film and method for making same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2549103