Optical assembly for rear projection television

Optics: image projectors – Cabinet encloses projector and one side of screen

Reexamination Certificate

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Details

C353S077000, C353S078000, C353S079000, C353S098000, C353S099000, C348S744000, C348S745000

Reexamination Certificate

active

06719432

ABSTRACT:

BACKGROUND OF INVENTION
1. Field of the Invention
The present invention relates to a rear projection television, more particularly to anoptical assembly for rear projection television.
2. Description of the Related Art
In recent years, as the opto-electronic technology grows rapidly, the visualization of information becomes more and more important. The significance and demand for rear projection television as a display device increases drastically. Therefore, with the consideration of mass production and labor cost, the way of conveniently and quickly assembling a rear projection television, saving manpower and cost, and maintaining a high-brightness and high-resolution video quality to provide comfortable viewing screens for users, and being capable of quickly and conveniently processing the after-sale service and maintenance to strengthen the competitiveness in the market and popularly accepted by the consumer's market has become an important subject of the research and development in the industry.
Please refer to
FIG. 1
for the overall optical system structure of a prior-art rear projection television. A screen
10
in the front, a base
11
at the bottom, and a rear cover
12
at the backside constitute the interior of the rear projection television; wherein the interior of the rear projection television has a carrier
13
on the base
11
, and the carrier
13
has an optical engine
14
on it. A first mirror
15
is fixed in the front of the optical engine
14
, and furthermore a second mirror
16
is disposed on the inner side of the rear cover
12
at the back of the screen
10
. The operation of the optical system of the rear projection television is by means of generating a beam with video information from the optical engine
14
on the carrier
13
and projecting the beam onto the first mirror
15
. The beam is then reflected onto the second mirror
16
from the first mirror
15
, and finally onto the screen
10
, which constitutes the optical system projection architecture.
Since every component of the optical system of the rear projection television must have an accurate relative position and a projection angle to assure the distortion-free and aberration-free image produced by the optical system of the rear projection television, and such system has to be assembled in a clean room to prevent the optical components from being contaminated and to maintain a high-brightness and high-resolution video quality. However, the components of the optical system of the rear projection television such as the optical engine
14
, the first mirror
15
, the second mirror
16
, and the screen
10
are fixed individually on different major component units; there is not only error in the manufacture of the components, but also error in the manufacturing of the assembly. These errors will seriously affect the video quality of the screen. In the meantime, the illumination source and electronic components that easily generate heat are accommodated in the interior of the rear projection television with the optical components. Such arrangement is not only difficult to disperse heat, but the expansion and contraction due to temperature also affects the imaging quality of optical components. In addition, the whole set of the prior-art rear projection television has to be assembled in the clean room to prevent contamination by dust, and in turn will cause a higher manufacturing cost. It needs to disassemble the whole television set for the maintenance of optical components, which also makes the maintenance more difficult. Therefore, there are many shortcomings of the prior-art rear projection television, which require improvement.
SUMMARY OF INVENTION
The objective of the present invention is to provide an optical assembly for rear projection television, such that when the rear projection television is assembled, it minimizes the assembling error, and thus maintains good video quality.
The other objective of the present invention is to provide an optical assembly for rear projection television, which only requires unscrewing a small number of screws to remove the optical assembly, so that the optical system can be disassembled without affecting the relative position of the components of the optical system, which facilitates the maintenance very much.
A further objective of the present invention is to provide anoptical assembly for rear projection television wherein the projectingoptical components and heat generating components are separated, so that the video will not be affected by heat and thus maintains good video quality of the screen.
Another further objective of the present invention is to provide anoptical assembly for rear projection television, wherein the optical system has a sealed space so that when the rear projection television is assembled, only the optical system has to be assembled in a clean room, which can reduce the cost and make the maintenance simpler and more convenient.
To accomplish the aforementioned objectives, the rear projection television of the present invention comprises an optical assembly; an optical engine disposed on the lower carrier the optical assembly; a hood member coupled to an end of the carrier at the front end of the optical engine; an inlet disposed on the hood member, the inlet having an elastic sealed cover which allows the projection lens of the optical engine to be extended inside the hood member and closely wraps the external diameter of the projection lens; a first mirror disposed in front of the projection lens; a second mirror is disposed on the upper end of the inner side of the hood member along the optical path of the small reflective projection lens. A screen is coupled to the outlet of the hood member along the optical reflection path of the second mirror. Covering the components one by one by means of a hood member and a screen according to the size of the optical path and excluding the optical engine of the heat-generating element outside constitute a sealed space with an isolation of air from the exterior for preventing the external dust, moisture, and temperature. Thus, such arrangement constitutes an optical assembly of the present invention.


REFERENCES:
patent: 4730919 (1988-03-01), Schuch
patent: 5408283 (1995-04-01), Lee
patent: 5521659 (1996-05-01), Arnott
patent: 5829855 (1998-11-01), Uchiyama
patent: 5860720 (1999-01-01), Negishi et al.
patent: 5890787 (1999-04-01), McNelley et al.
patent: 6046860 (2000-04-01), Hirata et al.
patent: 2003/0179349 (2003-09-01), Fukunaga et al.

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