The present invention relates to a projection apparatus, and more particularly to a projection apparatus and a light integration rod for the same.
In the design of a digital light processing (DLP) projector, on-, off- and flat-states optical paths in respective of the position of the projection lens aperture has to be considered. The on-, off- and flat-states optical paths correspond to the positions of micromirrors in the digital micromirror device (DMD). In other words, on-state optical path is the transmission path of light beams reflected by on-state micromirrors (or “on-state light beam” hereinafter), and would pass through the projection lens; analogously, off-state optical path is the transmission path of light beams reflected by off-state micromirrors (or “off-state light beam” hereinafter), and would deviate from entering the projection lens; otherwise, flat-state optical path is the transmission path of light beams reflected by flat-state micromirrors (or “flat-state light beam” hereinafter).
To improve light utilization efficiency of the projectors, projection lenses with larger apertures are typically chosen so as to increase the area of light reception.
While light leakage caused by flat-state light beams entering the aperture may be avoid by adopting a projection lens with a smaller aperture, on-state light beams may not be able to pass through the aperture fully, therefore resulting in reduction in light utilization efficiency of the projection device.
Therefore, the present invention provides a projection apparatus with enhanced light utilization efficiency and contrast.
Another embodiment of the present invention provides a light integration rod for enhancing the light utilization efficiency and contrast of the projection apparatus.
The projection apparatus according to an embodiment of the present invention includes a light source module, a light valve, a light integration rod, and a projection lens. The light source module is configured for providing an illuminating light beam. The light valve is disposed on the transmission path of the illuminating light beam for converting the illuminating light beam into an image light beam. The light integration rod is disposed between the light source module and the light valve. The light integration rod includes a light input end and a light output end opposite to the light input end; the light input end includes a plurality of first sides having a length of X1 and a plurality of second sides having a length of Y1; and the light output end includes a plurality of third sides having a length of X2 and opposite to the first sides and a plurality of fourth sides having a length of Y2 and opposite to the second sides, wherein X2/X1>Y2/Y1. The projection lens is disposed on the transmission path of the image light beam.
The light integration rod according to an embodiment of the present invention includes a light input end and a light output end opposite to the light input end. The light input end includes a plurality of first sides having a length of X1 and a plurality of second sides having a length of Y1; and the light output end includes a plurality of third sides having a length of X2 and opposite to the first sides and a plurality of fourth sides having a length of Y2 and opposite to the second sides, wherein X2/X1>Y2/Y1.
In an embodiment of the present invention, the shape of the light output end of the light integration rod corresponds to the shape of the active surface of the light valve.
In an embodiment of the present invention, the shape of the light input end of the light integration rod corresponds to the shape of the output surface of the light source module.
In an embodiment of the present invention, the first sides and the third sides are parallel to a first direction, the second sides and the fourth sides are parallel to a second direction, and the first direction is perpendicular to the second direction.
In an embodiment of the present invention, X1<X2.
In an embodiment of the present invention, Y1>Y2.
In an embodiment of the present invention, Y1<Y2.
In an embodiment of the present invention, X1<Y1.
In the projection apparatus according to the embodiments of the present invention, the light integration rod includes a first side with a length of X1 and a second side with a length of Y1 at the light input end and a third side with a length of X2 and a fourth side with a length of Y2 at the light output end, which satisfy the equation: X2/X1>Y2/Y1, so that images of exit pupil of the illuminating light beam at the light output end of the light integration rod are effectively narrowed. In this way, on-state light beams are fully utilized by the projection apparatus and light leakage caused by flat-state light beams is prevented. Therefore, the light integration rod of the present invention is effective in enhancing light utilization efficiency and contrast of the projection apparatus.
For making the above and other purposes, features and benefits become more readily apparent to those ordinarily skilled in the art, the preferred embodiments and the detailed descriptions with accompanying drawings will be put forward in the following descriptions.
The present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:
The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed.
Referring now to
The light source module 110 of the present embodiment may include at least one light-emitting diode (LED) component, but is not limited to any specific type of light source. Optical lenses, reflective sheets, prisms, or other optical components may be disposed between the light source module 110 and the light integration rod 130 or between the light integration rod and the light valve 120 according to specific needs. The light valve 120 of the present embodiment is a reflective light valve, such as a digital micromirror component comprised of a plurality of micromirrors 122 that are arranged in arrays. It is to be understood that
The present invention modifies the structure of existing light integration rods, with the aim of enhancing both the light utilization efficiency and the contrast of projection devices. Structure of the light integration rod 130 of the present embodiment is described in detail as follows.
Referring now to
In the present embodiment, the light input end 131 of the light integration rod 130 is rectangular, and has two opposite first sides 133 and two opposite second sides 134 that are perpendicular to the first sides 133. Length X1 of the first sides 133 is smaller than length Y1 of the second sides 134. The light output end 132 of the light integration rod 130 may also be rectangular, and has two opposite third sides 135 and two opposite fourth sides 136 that are perpendicular to the third sides 135. The first sides 133 and the third sides 135 are parallel to a first direction D1, and the second sides 134 and the fourth sides 136 are parallel to a second direction D2. The first direction D1 is perpendicular to the second direction D2; for example, the first direction D1 may be parallel to axis X as shown in
The light integration rod 130 further includes a plurality of lateral surfaces between the light input end 131 and the light output end 132. In the present embodiment, the light integration rod 130 has four lateral surfaces 137a, 137b, 137c and 137d; however, the present invention is not limited thereto. The lateral surface 137a is opposite to the lateral surface 137c, and the lateral surface 137b is opposite to the lateral surface 137d. The lateral surfaces 137a and 137c diverge along direction -Z (that is, from the light input end 131 toward the light output end 132), while the lateral surfaces 137b and 137d converge along the same direction -Z. All of the lateral surfaces 137a, 137b, 137c and 137d are trapezoidal, therefore resulting in X2>X1 and Y2<Y1.
In the present embodiment, length X1 of the first sides 133 and length Y1 of the second sides 134 at the light input end 131 and length X2 of the third sides 135 and length Y2 of the fourth sides 136 at the light output end 132 satisfy the equation: |(X2−X1)/X1|>|(Y2−Y1)/Y1|. In other words, the trend change between the light input end 131 and the light output end 132 along the first direction D1 is greater than that along the second direction D2, or simply X2/X1>Y2/Y1. Narrowing of the illuminating light beam N1 and adjustment of the images of exit pupil at the light output end 132 to non-circular images by the light integration rod 130 are described in detail as follows.
Referring now to
Accordingly, as the angle of output θ4 is smaller than the angle of input θ3 and the angle of output θ2 is greater than the angle of input θ1, the length of the illuminating light beam N1 along axis Y would be greater than that along axis X, therefore forming a non-circular image of exit pupil at the light output end 132. The illuminating light beam N1 would then be converted into the image light beam M1 by the light valve 120 and incident the projection lens 140. Consequently, the image of entrance pupil of the image light beam M1 transmitted to the projection lens 140 would be similar to elliptical in shape.
Referring now to
Referring again to
It is to be understood that the present invention is not limited to Y2<Y1 as exemplified in the aforementioned embodiment. In another embodiment, lengths of the sides the light integration rod 130 may satisfy the equation: Y2>Y1. Narrowing of the image of exit pupil of the illuminating light beam N1 at the light output end 132 can be accomplished as long as X2/X1>Y2/Y1 or |(X2−X1)/X1|>|(Y2−Y1)/Y1| is satisfied
Referring now to
In the present embodiment, the light input end 231 of the light integration rod 230 is rectangular, and has two opposite first sides 233 and two opposite second sides 234 that are perpendicular to the first sides 233. The light output end 232 of the light integration rod 230 may also be rectangular, and has two opposite third sides 235 and two opposite fourth sides 236 that are perpendicular to the third sides 235. The light integration rod 230 further includes a plurality of lateral surfaces between the light input end 231 and the light output end 232. In the present embodiment, the light integration rod 230 has four lateral surfaces 237a, 237b, 237c and 237d; but note the present invention is not limited thereto. The lateral surface 237a is opposite to the lateral surface 237c, and the lateral surface 237b is opposite to the lateral surface 237d. All of the lateral surfaces 237a, 237b, 237c and 237d diverge from the light input end 231 toward the light output end 232 and are all trapezoidal, therefore resulting in X1<X2 and Y1<Y2.
In the present embodiment, as length X1 of the first sides 233 and length Y1 of the second sides 234 at the light input end 231 and length X2 of the third sides 235 and length Y2 of the fourth sides 236 at the light output end 232 satisfy the equation: X2/X1>Y2/Y1, narrowing of the illuminating light beam N1 and adjustment of the images of exit pupil at the light output end 232 to non-circular images are accomplished.
In sum, the projection apparatus according to the aforementioned embodiments of the present invention, the light integration rod includes a first side with a length of X1 and a second side with a length of Y1 at the light input end and a third side with a length of X2 and a fourth side with a length of Y2 at the light output end, which satisfy the equation: X2/X1>Y2/Y1, so that images of exit pupil of the illuminating light beam at the light output end of the light integration rod are effectively narrowed to non-circular images. In this way, on-state light beams are fully utilized by the projection apparatus and light leakage caused by flat-state light beams is prevented. Therefore, the light integration rod of the present invention is effective in enhancing light utilization efficiency and contrast of the projection apparatus.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
Number | Date | Country | Kind |
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104120038 | Jun 2015 | TW | national |