This application claims the priority benefit of Taiwan application serial no. 93133307, filed on Nov. 2, 2004. All disclosure of the Taiwan application is incorporated herein by reference.
1. Field of Invention
The present invention relates to an optical projection apparatus. More particularly, the present invention relates to an optical projection apparatus, which can project a darker image with higher contrast and better uniformity.
2. Description of Related Art
In recent years, the projection apparatus of cathode ray tube (CRT) with large volume and weight has been gradually replaced by the liquid crystal display projection apparatus and the digital light processing (DLP) projection apparatus. These products have the properties of being light and portable, and can be directly connected to digital products and project images for display. Under the situation that the manufacturers continuously provide cheaper and more competitive products with additional function, these products are not only used by company, school, and other public place for the briefing tools, but also for viewing video at home. Therefore, it is an important issue to increase the image quality of the projection apparatus so as to increase the competitiveness of the product.
As mentioned above, conventionally, a “Dynamic Black” technology is used to increase the image quality, wherein a movable beam breaker is added in the projection lens unit. This beam breaker can move according to the different brightness level of the image so as to change the contrast of the image, and further improve the image quality.
In
In the foregoing optical projection apparatus 100, the light beam 112 provided from light source 112 passes through the color wheel 114, the light integration rod 116 and the relay lens 118, and is reflected to the DMD 130 via the total internal reflection (TIR) prism 119. This DMD 130 has a plurality of micro mirrors (not shown). Wherein, the micro mirrors in the ON state reflect the light beam 112a to the projection lens unit 120, while the micro mirrors in the OFF state deflect the light beam 112a away from the projection lens unit 120. Then, the light beam 112a being reflected to the projection lens unit 120 is projected to screen 300 to form an image.
In
However, since the beam breaker 140 only blocks one side of the light beam 120a, it causes the defect that one side of the projected image is darker, while the other side is brighter. In addition, the projection lens unit 120 needs to be cut, so as to allow the beam breaker 140 to move in the projection lens unit 120. Thus, if the cutting portion of the projection lens unit 120 is too large, then the structure of the projection lens unit 120 is destroyed, and the projection lens unit 120 is in risk to be broken. On the contrary, if the cutting portion of the projection lens unit 120 is too small, then the beam breaker 140 can just block a little portion of the light beam 112a. As a result, it cannot effectively increase the contrast of the darker image.
One objective of the present invention is to provide an optical projection apparatus using two beam breakers so as to project a darker image with higher contrast and more uniformity.
Another objective of the present invention is to provide an optical projection apparatus having a light source with multiple output powers so as to project a darker image with higher contrast and more uniformity.
Still another objective of the present invention is to provide an optical projection apparatus using a light attenuator so as to project a darker image with higher contrast and more uniformity.
Still another objective of the present invention is to provide an optical projection apparatus having a beam breaker with multiple holes so as to project a darker image with higher contrast and more uniformity.
In accordance with the foregoing objectives and others, the present invention proposes an optical projection apparatus, including an illumination system, a projection lens unit, a reflective light valve, a first beam breaker, and a second beam breaker. Wherein, the illumination system is used to provide a light beam. The projection lens unit and the reflective light valve are disposed on the transmission path of the light beam, and the reflective light valve is located between the illumination system and the projection lens unit. In addition, the first beam breaker and the second beam breaker can cut into the transmission path from different directions, so as to respectively block a portion of the light beam, and allow the other portion of the light beam to pass.
The present invention further provides an optical projection apparatus, which includes an illumination system, a projection lens unit, a reflective light valve, and a beam breaker. Wherein, the illumination system includes a light source capable of providing a light beam, and the light source has multiple output powers. The projection lens unit and the reflective light valve are disposed on the transmission path of the light beam. The reflective light valve is located between the illumination system and the projection lens unit. In addition, the beam breakers are disposed in the projection lens unit, and the beam breakers can cut into the projection lens unit to block a portion of the light beam. During the period when the beam breakers cut into the projection lens unit, the light source outputs a first power. During the other period, the light source outputs a second power, and the second power is larger than the first power.
The present invention further provides an optical projection apparatus, which includes an illumination system, a projection lens unit, a reflective light valve, a beam breaker, and a light attenuator. Wherein, the illumination system is capable of providing a light beam. The projection lens unit and the reflective light valve are disposed on the transmission path of the light beam, and the reflective light valve is located between illumination system and the projection lens unit. In addition, the beam breaker is implemented on the projection lens unit, and the beam breaker can cut into the projection lens unit to block a portion of the light beam. In addition, the light attenuator is implemented in the illumination system and the light attenuator can cut into the transmission path of the light beam in the illumination system.
The present invention further provides an optical projection apparatus, which includes an illumination system, a projection lens unit, a reflective light valve, and a beam breaker. Wherein, the illumination system is capable of providing a light beam. The projection lens unit and the reflective light valve are disposed on the transmission path of the light beam, and the reflective light valve is located between illumination system and the projection lens unit. In addition, the beam breaker with multiple holes is implemented on the projection lens unit, and the beam breaker can cut into the projection lens unit, to block a portion of the light beam.
The present invention uses two beam breakers. During the period when optical projection apparatus projects a darker image, the two beam breakers can cut into the transmission path of the light beam from different directions, to block a portion of the light beam. Therefore, the optical projection apparatus of the present invention can project a darker image with higher contrast and better uniformity.
In addition, the present invention uses a light source with multiple output powers or a light attenuator in the optical projection apparatus. During the period when a darker image is projected, the intensity of the light beam incident to the projection lens unit is reduced. As a result, the beam breaker only needs to block a small portion of the light beam, resulting in the contrast of the darker image. In addition, since the blocked portion of the light beam is less, the uniformity of the darker image being projected is improved.
In addition, the present invention uses the beam breaker with the multiple holes, whereby a portion of the light beam can pass through the holes. Thus, not only the contrast of the darker image can be improved, but also the uniformity of the darker image can be increased.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
In
In the foregoing optical projection apparatus 200, the light beam 212a provided from the light source 212 sequentially passes through the color wheel 214, the light integration rod 216, and the relay lens 218. Then, a total internal reflection prism 219 reflects light beam 212a to the reflective light valve 230. The reflective valve 230 can be a DMD or a LCOS panel. In the embodiment, the DMD is taken as an example. The DMD has a plurality of micro mirrors (not shown), in which the micro mirrors in the ON state can reflect the light beam 212a to the projection lens unit 220, and the micro mirrors in the OFF state can deflect the light beam 212a away from the projection lens unit 220. Then, the light beam 212a reflected to the projection lens unit 220 is projected to a screen 300 to form an image.
In
As described above, when the optical projection apparatus 200 projects the darker image, a portion of the light beam 212a is blocked so that the brightness for the darker image can be reduced and thereby the contrast of the darker image is improved. In addition, since the two beam breakers 240 and 250 cut in from different directions, the occurrence of the darker image with a larger brightness on one side thereof and a smaller brightness on the other side thereof is reduced. As a result, the uniformity of the darker image can be increased. In addition, since the embodiment uses two beam breakers 240 and 250, which simultaneously block a portion of the light beam 212a so that the angle θ for cutting in the projection lens unit 220 is not necessary to be large, and the objective of significantly increasing the contrast is achieved. Therefore, the cutting portion of the projection lens unit 220 is less, and the risk of being broken is reduced.
In
In addition, referring to
Referring to
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It should be noted that the light attenuator 260 in
Referring to
It should be noted in the embodiment of the present invention that the beam breaker 240 with multiple holes 242, light source 212 with multiple output power, and the light attenuator 260 (shown in
In sum, the optical projection apparatus of the present invention uses two beam breakers. During the period when optical projection apparatus projects a darker image, the two beam breakers can cut into the transmission path of the light beam from different directions to block a portion of the light beam. Therefore, the optical projection apparatus of the present invention can project a darker image with higher contrast and better uniformity. Also, since the angle θ for cutting in the projection lens unit 220 is not necessary to be large, the objective of significantly increasing the contrast is achieved. Therefore, the cutting portion of the projection lens unit 220 is less, and the risk for the projection lens unit 220 to be broken is reduced.
In addition, the optical projection apparatus can be implemented with light source with multiple output powers and/or the light attenuator, so that the light beam incident to the projection lens unit is reduced when the optical projection apparatus projects a darker image. As a result, the cutting portion of the projection lens unit becomes less, and the projection lens unit is not easy to be broken. Also, since the portion of the light beam bring blocked is less, the uniformity of the darker image can be further improved. In addition, the optical projection apparatus of the present invention can use the beam breaker with holes, such that a portion of the light beam can pass through the holes, and the uniformity of the darker image can be further improved.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing descriptions, it is intended that the present invention covers modifications and variations of this invention if they fall within the scope of the following claims and their equivalents.
Number | Date | Country | Kind |
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93133307 | Nov 2004 | TW | national |