This invention relates to the field of display systems, more particularly to cinema display systems, more particularly to cooling systems used to cool lamp reflectors in cinema display systems.
The recent introduction of all-digital cinematic display systems has presented a variety of challenges. One such challenge is the replacement of traditional film projectors with the new digital projectors while minimizing the costs involved in the change from traditional film projectors to digital projectors. To minimize initial costs, it is important for the digital projector to be able to use an existing projection booth. Additionally, modern digital projectors must make use of as much of the same equipment currently found in most cinema projection booths as possible. Among the equipment shared by both the film-based and all digital projectors is the lamp console.
Although the digital projectors are able to utilize traditional lamp consoles, the digital projectors typically require a unique reflector. The f-number of the reflectors used by the digital projectors is lower, for example f/1.5, than used by the film projectors. Additionally, the reflector is deeper. The arc lamp is also positioned closer to the back of the reflector in digital projectors than in film-based projectors. Positioning the arc lamp closer to the back of the reflector heats the inside of the back of the reflector much more than the shallower reflectors of traditional film projectors.
The new reflector design has been difficult to cool sufficiently. Without proper cooling of the back of the reflector, the reflector degrades over time and must be replaced, often after only a few months. What is needed is a method and system to properly cool the lamp and reflector in order to extend the useful life of the lamp and reflector in the digital cinema projectors.
Objects and advantages will be obvious, and will in part appear hereinafter and will be accomplished by the present invention which provides a method and system for cooling the lamp and lamp reflector in a cinema projector. One embodiment of the claimed invention provides a method of cooling a lamp reflector. The method comprising: providing a lamp reflector; providing a lamp bulb in the lamp reflector, the bulb extending through a hole in a center of the reflector; and providing an air deflector between the lamp reflector and the lamp bulb. The air deflector allows a portion of air entering the hole to cool the lamp bulb, and deflects another portion of the air entering the hole to cool an inner surface of the reflector.
According to another embodiment of the invention a lamp reflector assembly is provided. The lamp reflector assembly comprises: a lamp reflector; a lamp bulb in the lamp reflector, the bulb extending through a hole in a center of the reflector; and an air deflector between the lamp reflector and the lamp bulb. The air deflector allows a portion of air entering the hole to cool the lamp bulb, and deflects another portion of air entering the hole to cool an inner surface of the reflector.
Yet another embodiment of the present invention provides an air deflector for use in cooling lamp reflectors. The air deflector comprising: a central cylindrical body portion, an opening in the central cylindrical body portion providing clearance for air to pass through the body and around a lamp extending through the body; and at least one vane portion extending from one end of the body portion, the vane portion operable to deflect a portion of air entering the hole to cool an inner surface of the reflector.
Spring clips are generally used to hold the air deflector in the central portion of the reflector, spaced apart from the lamp. In this manner, a small deflector is used to separate the cooling airflow entering the reflector into a portion cooling the lamp and a portion cooling the inside surface of the reflector.
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
Traditional reflectors are warranted to withstand temperatures up to 25020 C. The larger reflectors used by digital projectors, however, position the arc lamp much closer to the back of the reflector. This raises the temperature as high as 300° C. The higher temperature eventually deforms the reflector, reducing the ability of the reflector to properly focus light. The higher temperature also degrades the inner mirrored surface of the reflector. As a result, the light available for projection is reduced from 12,000 lumens to 7,000 lumens in a matter of a few months and the reflector must be replaced.
The air input forced into the plenum 104 along path 106 is forced out an opening around the lamp 102 in the center of the reflector 100. This air cools the lamp, preventing degradation of the lamp glass. The air flow, however, does not provide efficient or uniform cooling of the back portion of the reflector nearest the lamp arc. To improve the cooling efficiency and ensure uniform cooling of all portions of the back of the reflector, a deflector 108 has been developed.
As shown in
Clips 600 shown in
Alternate embodiments permanently fix the deflector to the reflector, or attach the deflector to the lamp. Although it is possible to attach the deflector directly to the lamp, the extreme temperatures reached by the lamp, and the concern of electrical contact between the deflector and the lamp, make it advantageous to attach the deflector to the reflector and to avoid contact with the lamp.
Thus, although there has been disclosed to this point a particular embodiment for an air deflector and method for cooling a lamp reflector, it is not intended that such specific references be considered as limitations upon the scope of this invention except insofar as set forth in the following claims. Furthermore, having described the invention in connection with certain specific embodiments thereof, it is to be understood that further modifications may now suggest themselves to those skilled in the art, it is intended to cover all such modifications as fall within the scope of the appended claims.
This application claims priority of U.S. patent application Ser. No. 60/302,317 filed 30 Jun. 2001.
Number | Name | Date | Kind |
---|---|---|---|
3486019 | Bryant et al. | Dec 1969 | A |
4931912 | Kawakami et al. | Jun 1990 | A |
5207505 | Naraki et al. | May 1993 | A |
5947592 | Barlow | Sep 1999 | A |
6042253 | Fant et al. | Mar 2000 | A |
6132061 | Andrus et al. | Oct 2000 | A |
6203173 | Duff et al. | Mar 2001 | B1 |
6227686 | Takahashi et al. | May 2001 | B1 |
6497507 | Weber | Dec 2002 | B1 |
6578991 | Beaumont | Jun 2003 | B2 |
6746325 | Crane | Jun 2004 | B2 |
20010022727 | Beaumont | Sep 2001 | A1 |
Number | Date | Country | |
---|---|---|---|
20030021120 A1 | Jan 2003 | US |
Number | Date | Country | |
---|---|---|---|
60302317 | Jun 2001 | US |