Patent Application
20070171386
(A) Field of the Invention
The present invention relates to a projector having a brightness-adjusting module and method for adjusting brightness for the same, and more particularly, to a projector having a brightness-adjusting module configured to adjust an output brightness by changing the position of a light integrator with respect to a reflector of the projector and method for the same.
(B) Description of the Related Art
Among many large-sized billboards, the video wall has been widely used in some populous areas to attract consumers' attention by the excellent audio-visual effect of the video wall so as to achieve maximum advertisement exposure.
Conventional technique adjusts the brightness of the four display units 62A, 62B, 62C and 62D by changing the power of the light-emitting device such as a lamp burner of the display unit. However, this technique offers only a small tuning range, which does not meet the practice requirement.
The primary objective of the present invention is to provide a projector having a brightness-adjusting module and method for the same, which change the position of a light integrator with respect to a reflector to adjust the output brightness of the projector so as to show an excellent image having a uniform brightness.
In order to achieve the above-mentioned objective and avoid the problems of the prior art, one embodiment of the present invention discloses a projector comprising a light-emitting device including a lamp burner for generating light beams and a reflection unit such as a reflector for focusing the light beams to a predetermined region, a light integrator positioned at the predetermined region and a brightness-adjusting module for adjusting brightness of the projector by changing the position of the reflector with respect to the light integrator. Preferably, the reflector is an elliptical reflector having two foci, with the lamp burner positioned at one of the two foci, and the other focus positioned at the predetermined region. The brightness-adjusting module comprises a platform configured to load the reflector and a moving apparatus configured to move the platform. Particularly, the moving apparatus comprises a rack positioned on a side of the platform, a gear configured to drive the rack through rotation so as to move the platform and a motor configured to drive the gear.
According to another embodiment of the present invention, a method for adjusting the brightness of a projector is characterized by brightness adjustments made by changing the position of a light integrator with respect to a reflector of the projector. The present invention possesses an adjusting range higher than that of the prior art; therefore, the present invention can solve the shortage of different brightness levels among these display units and improve the quality of the displayed image.
The objectives and advantages of the present invention will become apparent upon reading the following description and upon reference to the accompanying drawings in which:
The projector 30 may further comprise a color wheel 46, relay lens 40, a micromirror device 42, projection lens 48 and an image-displaying device 44 such as a screen of a video wall. Preferably, the reflector 34 is an elliptical reflector having two foci, the lamp burner 32 is positioned at one of the two foci, and the other focus is positioned at the predetermined region 38. The micromirror device 42 can be controlled by digital technique or analog technique.
Referring to
The moving apparatus 55 can be positioned on other sides of the platform 52, i.e., forming a platform capable of moving in a three dimensional manner to change the position of the light integrator 38 with respect to the reflector 34 in a three dimensional manner. In other embodiments, the brightness-adjusting module 50 are the arrangement of slide and platform, and motors or driving units can be used to move the platform up and down, forward and backward, rightward and leftward, or to pull the platform to change the position of the light integrator 38 with respect to the reflector 34.
Referring to
In other cases where the elliptical reflector 34 together with lamp burner 32 therein are moved to another vertical position B (the intensity distribution can be represented by a Gaussian distribution curve B′) by the brightness-adjusting module 50, while the position of the light integrator 38 is kept the same, i.e., changes the position of the elliptical reflector 34 with respect to the light integrator 38. Since the portion of the Gaussian distribution curve B′ having a maximum intensity does not fall in the light integrator 38, the projector 30 possesses a lower output brightness.
In brief, the output brightness of the projector 30 can be increased by changing the position of the elliptical reflector 34 with respect to the light integrator 38 such that the lamp burner 32 at one of the foci of the elliptical reflector 34 and the light integrator 38 at another focus of the elliptical reflector 34 have the same vertical position. Inversely, the output brightness of the projector 30 can be decreased by changing the position of the elliptical reflector 34 with respect to the light integrator 38 such that the vertical position of the lamp burner 32 at one of the foci of the elliptical reflector 34 deviates from that of the light integrator 38 at another focus of the elliptical reflector 34.
In other words, if an offset represents the deviation of the vertical position of the lamp burner 32 from the vertical position of the light integrator 38, increasing the offset decreases the output brightness of the projector 30 and vice versa. Consequently, applying the present invention to the video wall 60 can adjust the brightness of these display units 62A, 62B, 62C and 62D individually by changing the position of the elliptical reflector 34 with respect to the light integrator 38 of the projector 30 positioned in these display units 62A, 62B, 62C and 62D. Consequently, these four display units 62A, 62B, 62C and 62D may have a uniform brightness to show a high quality image.
The above-described embodiments of the present invention are intended to be illustrative only. Numerous alternative embodiments may be devised by those skilled in the art without departing from the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 095102787 | Jan 2006 | TW | national |
