Color wheel and optical device employing same

A projector includes a light source assembly, a digital micro-mirror device, and a projection lens. The light source assembly includes a lamp and a color wheel positioned for receiving light generated by the lamp. The color wheel includes a motor having a contacting portion, a filter, a light-blocker, and a light-isolating sheet. The filter is mounted on the contacting portion of the motor and includes a first area and a second area. Light beams used for forming an image only pass through the first area. The light-blocker is disposed on the filter opposite to the motor. The light-isolating sheet is disposed on the first area and positioned between the filter and the motor and configured for isolating the light beams arrived on the second area.

BACKGROUND

1. Technical Field

The present disclosure relates to a color wheel and an optical device having the same.

2. Description of the Related Art

In general, an optical engine is provided in a display apparatus such as a projection television, a projector, or the like, for projecting an image on a screen. Such an optical engine is classified into various types, e.g., cathode ray tube (CRT) type, liquid crystal display (LCD) type, digital light processing (DLP) type, and the like according to display devices for displaying processed video data. The DLP type optical engine conventionally includes a color wheel. The color wheel includes a number of color filters for selectively filtering red (R), green (G) or blue (B) lights out of white light emitted from a light source. The color wheel is rotatable for allowing the white light emitted from the light source to selectively pass through one of the color filters. Currently, color wheels are constructed with the color filters glued to a filter supporter. As a consequence, color filters fall off because of centrifugal force generated by high-speed rotation of the color wheel overcoming the bond of the glue.

What is needed, therefore, is a color wheel that can overcome the above-described shortcoming.

DETAILED DESCRIPTION

A detailed explanation of an optical device having a color wheel according to an exemplary embodiment will now be made with references to the drawings attached hereto.

Referring toFIG. 1, a projector100as an optical device according to the exemplary embodiment is shown. The projector100includes a light source assembly10, a digital micro-mirror device (DMD)20, and a projection lens30. The DMD20is positioned for receiving light beams generated by the light source assembly10. The projection lens30is disposed in the reflecting-light path of the digital micro-mirror device20. The projector100also includes a mirror40for changing the path of the light transmitted by the light source assembly10, as desired.

The light source assembly10includes a lamp11and a color wheel12positioned for receiving light beams generated by the lamp11. The lamp11is configured for providing light beams for the projector100and can be a halogen lamp, a metal halogen lamp, a LED, or the like. In the present embodiment, the lamp11is a halogen lamp that emits a white light.

The color wheel12is configured for splitting the light beams output from the lamp11into red, green and blue light beams. Referring also toFIGS. 2 and 3, the color wheel12includes a motor13, a filter14, an adhesive material15, a light-blocker16, and a light-isolating sheet17.

The motor13includes a rotor131having an electromagnetic assembly consisted of magnets, silicon steel sheets, wires, and the like, and a stator (not shown). When the motor13is on, the electromagnetic assembly drives the rotor131to rotate the filter14. An end of the rotor131has a rotating plate132disposed thereon. A contacting portion133is defined on the rotating plate132for fixing the filter14.

The filter14may be a circular transparent substrate and is separated into a number of fans. Different parameter filter films are respectively coated on the fans for passage of light beams of different wavelength. In present embodiment, the transparent substrate is made of glass. The filter14is fixed on the contacting portion133by the adhesive material15. The adhesive material15may be an epoxy. The filter14includes a first area141and a second area142. Light beams used for projecting an image pass through the first area141and do not pass through the second area142.

The light blocker16is fixed on the filter14opposite to the motor13for preventing the light beams directly striking on the adhesive materials15. The light blocker16is made of the same material as the filter14. Therefore, the light blocker16has a same thermal expansion coefficient with the filter14so as to generate a same thermal stress on the light blocker16and the filter14, which can prevent damage to the filter14and the light blocker16by expansion and contractions of the parts caused by temperature changes.

The light-isolating sheet17is positioned between the filter14and the light blocker16for preventing stray light striking on the second area142of the filter14to protect the adhesive materials15. The light-isolating sheet17may be one of a UV-filter film, a metal layer, an ink layer or a dielectric layer, which is adhered on the second area142of the filter14. It also may be an atomizing layer defined on the second area142. In present embodiment, the light-isolating sheet17is a UV-filter film. The area of the light-isolating sheet17is the same as that of the second area142for fully covering the second area142.

The DMD20is configured for superimposing spatial information on the light beams output by the color wheel12.

The projection lens30is configured for receiving the light output from the DMD20and magnifying and projecting an image formed by the light output on a screen.

Thus, the adhesive material15in the projector100according to the exemplary embodiment of the present disclosure includes can be maintained in good condition due to the protection of the light-blocker16, together with the light-isolating sheet17. Accordingly the filter14is stably mounted even when the color wheel12rotates at high speed. As described above, the present embodiment provides a color wheel12and an optical device with the same in which a filter14is prevented from radially breaking away even though the color wheel12rotates at high speed.