Optics: image projectors – Reflector – Plural
Reexamination Certificate
2003-11-25
2004-08-17
Adams, Russell (Department: 2851)
Optics: image projectors
Reflector
Plural
C359S850000, C348S771000
Reexamination Certificate
active
06776492
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a multiple reflective mirrors module, and especially, to a multiple reflective mirrors module for an optical engine.
BACKGROUND OF THE INVENTION
Due to the rapid progress of the optical and semiconductor technology, office machines, such as fax machines, copy machines, scanners, printers, and optical projectors not only enjoy reduced size but increased accuracy. Currently, color image displays, such as optical projectors, are in high demand due to the great progress of multimedia and network technologies. Therefore, portable optical projectors are undergoing continuous development. Optical projection technologies have progressed successfully and the price, volume and weight thereof have decreased while the market for the same has increased.
The market for digital optical projectors continues to expand due to commercial presentation and home theater demands. In early stages, the optical projector utilized a cathode ray tube (CRT) to project the images through an enlarging lens and onto a display screen. The CRT projector utilizes the RGB color separation method to reproduce the color images on the display screen. Therefore, a CRT projector must use three sets of lens for RGB, respectively. The size, volume, weight and cost are difficult to reduce. In particular, the focusing accuracy of the three color guns is very difficult to adjust. Hence, the CRT projector has gradually been replaced.
Digital optical projectors have only one gun and enjoy superior performance, reduced volume and cheaper cost. Current digital projectors include liquid crystal display (LCD) projectors, digital light processing (DLP) projectors, and liquid crystal on silicon (LCOS) projectors. LCD projectors utilize light streams that pass directly through a lens to reproduce color images. DLP and LCOS projectors utilize high luminance light streams projected on display elements and reflect these light streams through a lens to reproduce color images.
At present, LCD projectors are the mainstream digital optical projectors. However, the DLP projectors provide advantages of light-weight machinery and high image quality and are gradually equaling the market share of the LCD projectors. In addition, the LCOS projectors produced by the semiconductor manufacture process can easily enhance the image resolutions and simplify the manufacture process to reduce the cost thereof. Hence, the LCOS projector is an up-and-coming optical projector.
The DLP projector is the mainstream portable projector because it enjoys a high response speed, light weight, high light streams utility rate, and high image resolution. A DLP optical engine is a reflection-type optical engine. The DLP optical engine attaches a digital micro-mirror device (DMD) to a complementary metal-oxide semiconductor (COMS) memory and controls a tilt angle of each mirror by way of an electrode control to control the light stream reflection angle. A DMD chip is a micro-mirror chip produced by Texas Instruments. The DMD chip is based on a micro electromechanical system (MEMS) and is combined with the digital optical switch manufactured by a semiconductor manufacture process to construct the digital optical process technology, that is, the digital optical process technology combines the digital image process, memory manufacture technology, and optical process technology.
The reflection rate of the mirrors controlled by the electrodes of the DLP chip is about 95%. Further, with digital controls, the DLP projectors include higher luminance, more correct color reproduction, higher response speed, and lower noise than a LCD projector. Furthermore, due to the simple structure of the DLP projector, the DLP projector is lighter than a similar LCD projector.
The mirrors of the DLP projectors normally rotate between +10 degrees to −10 degrees according to the digital control signals. Each mirror corresponds to the CMOS memory to deal with the tilt angle thereof. However, the tilt angles of the mirrors are limited by technology and lifetime. Therefore, the tilt angle of the mirrors cannot be increased by much.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a multiple reflective mirrors module that efficiently increases the total working angle of thereof.
Another object of the present invention is to provide an optical engine with a multiple reflective mirrors module for use in various office machines.
To achieve these and other advantages and in accordance with the object of the invention, the present invention provides a multiple reflective mirrors module which is utilized in an optical engine. The multiple reflective mirrors module has a fixed reflective mirror, a first tilting reflective mirror, and a second tilting reflective mirror. The first tilting reflective mirror reflects an incident light to form a first reflected light and transmits the same to the fixed reflective mirror. The first reflected light is formed with an angle variation 2&thgr;
1
when the first tilting reflective mirror rotates an angle &thgr;
1
.
The second tilting reflective mirror is disposed opposite the fixed reflective mirror so that the first reflected light is reflected by the fixed reflective mirror and is transmitted to the second tilting reflective mirror and then is reflected by the second tilting reflective mirror to form a second reflected light The second reflected light is formed with an angle variation 2&thgr;
1
+2&thgr;
2
when the second tilting reflective mirror rotates an angle &thgr;
2
.
The first tilting reflective mirror and the second tilting reflective mirror are formed on a same substrate, such as a semiconductor silicon substrate. The optical engine is utilized in a projector, a laser printer, a copy machine, or a scanner. When the first tilting reflective mirror and the second tilting reflective mirror have a same rotationally axial direction, the second reflected light scans on a line segment. When the first tilting reflective mirror and the second tilting reflective mirror have respectively differently rotational axial directions, the second reflected light scans on a surface.
The fixed reflective mirror can be replaced by a third tilting reflective mirror to scan on a line segment or a surface. Furthermore, between the first tilting reflective mirror and the second tilting reflective mirror, the substrate can further comprises N tilting reflective mirror to enlarge the angle variation to 2(&thgr;
1
+&thgr;
2
+. . . +&thgr;
N+2
). In addition, the fixed reflective mirror can be replaced by N+1 tilting reflective mirror formed on another substrate and controlled by circuits formed on the other substrate.
Therefore, the multiple reflective mirrors module according to the present invention can enlarge the working angle of the optical engine and increase the lifetime thereof. Furthermore, the scanning speed of the optical engine can be increased and the manufacturing cost can be reduced.
REFERENCES:
patent: 6002507 (1999-12-01), Floyd et al.
patent: 6643069 (2003-11-01), Dewald
patent: 6705735 (2004-03-01), Chang et al.
patent: 2003/0133204 (2003-07-01), Chen et al.
patent: 2003/0179349 (2003-09-01), Fukunaga et al.
Adams Russell
Delta Electronics , Inc.
Koval Melissa J
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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