Lamp position adjustment device

A lamp position adjustment device includes a base plate, a supporting frame, a lamp holder, a first positioning mechanism, and a second positioning mechanism. The first positioning mechanism is disposed between the lamp holder and the supporting frame and between the lamp holder and the base plate to enable the lamp holder to move in a first direction relative to the supporting frame. The first direction is substantially parallel with one side of a light incident surface of an integration rod. The second positioning mechanism is disposed between the lamp holder and the base plate to enable the lamp holder to rotate about an axis parallel to the first direction.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority of application No. 097140387 filed in Taiwan R.O.C on Oct. 22, 2008 under 35 U.S.C. §119; the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a position adjustment device, and more particularly, to a lamp position adjustment device of a projector.

2. Description of the Related Art

FIG. 1shows a schematic diagram illustrating a conventional lamp module100used in a projector. The lamp module100includes a lamp102and a lamp holder104attached to a front end of the lamp102, where the lamp102screws on the lamp holder104through screws106. Typically, the brightest point of a lamp lies in the tip of a lamp wick. Hence, optimum brightness for a projected image is obtained when the position of the lamp12in space is optimized. However, manufacturing tolerances exist in the fabrication of each lamp. As shown inFIG. 1, once the lamp module100is installed on a projector (not shown) and fails to provide optimum brightness as a result of inferior positioning, the lamp module100needs to be re-installed to cure such deficiency, and the re-installation is inconvenient and time-consuming. Further, according to the conventional design, the lamp position fails to be adjusted independently in a selected direction, so an accurate position adjustment to correct manufacturing errors in each lamp is hardly achieved. This results in inferior output brightness of a projector.

BRIEF SUMMARY OF THE INVENTION

The invention relates to a lamp position adjustment device having simple positioning mechanisms to adjust the position of a lamp in two separate directions.

According to an embodiment of the invention, a lamp position adjustment device is used to shift a wick of a lamp to a position corresponding to a center of an integration rod. The lamp position adjustment device includes a base plate, a supporting frame, a lamp holder, a first positioning mechanism, and a second positioning mechanism. The supporting frame is fixed on the base plate, and the lamp holder is disposed in the supporting frame, presses against the supporting frame, and holds the lamp. The first positioning mechanism is disposed between the lamp holder and the supporting frame and between the lamp holder and the base plate to enable the lamp holder to move in a first direction relative to the supporting frame. The first direction is substantially parallel with one side of a light incident surface of the integration rod. The second positioning mechanism is disposed between the lamp holder and the base plate to enable the lamp holder to rotate about an axis parallel to the first direction.

In one embodiment, the first positioning mechanism includes an adjustment screw, a first spring, and a guide screw. The adjustment screw passes through the base plate to press against the lamp holder. The first spring is disposed between the supporting frame and the lamp holder and positioned opposite the adjustment screw for exerting an elastic force in the first direction on the lamp holder. The guide screw passes through the supporting frame and the lamp holder and is inserted into the first spring.

In one embodiment, the second positioning mechanism includes a guide slot formed on the lamp holder and a biased protrusion structure with a protrusion. The protrusion is inserted into the guide slot to force the lamp holder to rotate about the axis parallel to the first direction when the biased protrusion structure rotates. Besides, the second positioning mechanism may further include a pressing plate and a fixed spring. The pressing plate presses against the bottom of the biased protrusion structure to prevent the biased protrusion structure from slipping off the base plate. The fixed spring is disposed between the biased protrusion structure and the pressing plate to increase the friction between the biased protrusion structure and the pressing plate.

In one embodiment, the supporting frame is provided with at least one first fastening hole, the base plate is provided with at least one second fastening hole, and the position of the at least one second fastening hole corresponds to the position of the at least one first fastening hole. The lamp position adjustment device further includes at least one first fastening screw inserted into the at least one first fastening hole and the at least one second fastening hole to fix the supporting frame on the base plate. The lamp holder is provided with at least one third fastening hole, the base plate is provided with at least one fourth fastening hole, and the position of the at least one fourth fastening hole corresponds to the position of the at least one third fastening hole. The lamp position adjustment device further includes at least one second fastening screw inserted into the at least one third fastening hole and the at least one fourth fastening hole to fix the lamp holder on the base plate.

According to the above embodiment or the above embodiments, the position of a lamp may be adjusted in two separate directions by simple positioning mechanisms. Hence, no matter which position the lamp wick locates in space, optimum projection brightness is obtained simply by adjusting the position once along a first direction and further adjusting the position once along a second direction. Thereby, the lamp positioning process is simplified, the consumption of time of the lamp positioning process is reduced, and high positioning accuracy is also achieved.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIG. 2, the lamp position adjustment device10includes a base plate12, a supporting frame14, a lamp holder16, a first positioning mechanism18, and a second positioning mechanism22. The lamp position adjustment device10is used for shifting a lamp wick (not shown) to a position corresponding to a center of an integration rod24to provide optimum projection brightness. In this embodiment, the supporting frame14is provided with at least one first screw hole141, the base plate12is provided with at least one second screw hole121, and the position of the at least one first screw hole141is corresponding to the position of the at least one second screw hole121. For example, four first fastening screws26shown inFIG. 2are inserted into the first screw holes141and the second screw holes121to fix the supporting frame14on the base plate12. The lamp holder16is disposed in the supporting frame14and presses against the supporting frame14, and the lamp holder16holds a lamp (not shown). The first positioning mechanism18is disposed between the lamp holder16and the supporting frame14and between the lamp holder16and the base plate12. In this embodiment, the first positioning mechanism18includes an adjustment screw181, a compression spring182, and a guide screw183. The adjustment screw181passes through a first through hole122on the base plate12to press against a corner of the lamp holder16. The compression spring182is disposed between the supporting frame14and the lamp holder16and is positioned opposite the adjustment screw181. In this embodiment, the adjustment screw181and the compression spring182are respectively positioned at two ends of a diagonal line of the lamp holder16. After the adjustment screw181passes through the base plate12, the adjustment screw181is continually tightened inwardly to force the lamp holder16to move towards the upper left and to compress the compression spring182. In comparison, when the adjustment screw181is loosened outwardly, the compression spring182exerts an elastic force on the lamp holder16to force the lamp holder16to move towards the lower right. The guide screw183positioned opposite the adjustment screw181passes through the supporting frame14and the lamp holder16and is inserted into the compression spring182to hold the compression spring182and to ensure the position adjusting direction of the first positioning mechanism18. Hence, according to the diagonal arrangement of the adjustment screw181and the compression spring182(together with the guide screw183) in the first positioning mechanism18, the lamp holder16is allowed to move in a first direction P (shown inFIG. 3) relative to the supporting frame14when the adjustment screw181is tightened or loosened. Specifically, the first direction P is substantially parallel with a connecting line of the adjustment screw181and the guide screw183. In one embodiment, the first direction P is substantially parallel with one side24aof a light incident surface of the integration rod24.

The second positioning mechanism22includes a biased protrusion structure221and a guide slot222. The guide slot222is formed on a corner of the lamp holder16and substantially positioned at one end of a diagonal line of the lamp holder16. A second through hole123is formed on the base plate12at a position corresponding to the guide slot222, and the biased protrusion structure221has a protrusion221a. During assembly, after the biased protrusion structure221is inserted into the second through hole123on the base plate12, the protrusion221ais inserted into the guide slot222of the lamp holder16to force the lamp holder16to rotate as the biased protrusion structure221rotates. For example, when the biased protrusion structure221counterclockwise rotates along a rotation direction R shown inFIG. 3, the protrusion221ais shifted from one side (FIG. 4A) to the center (FIG. 4B) of the guide slot222to force the lamp holder16to clockwise rotate along a rotation direction Q. Referring toFIG. 3again, the first positioning mechanism18allows the lamp holder16to move in the first direction P parallel with one side24aof a light incident surface of the integration rod24. Besides, the second positioning mechanism22allows the lamp holder16to rotate along a rotation direction Q about an axis parallel to the first direction P, and thus a lamp wick28of the lamp is allowed to move in a direction substantially parallel with another side24bof the light incident surface of the integration rod24. Under the circumstance, the lamp wick28is allowed to move to a position corresponding to a center of the integration rod24quickly, as long as the position along the first direction P and the position along the rotation direction Q are each adjusted once.

Referring toFIG. 5, a rectangular black frame indicates a light incident surface of the integration rod24, the light incident surface has a first side24aand a second side24bperpendicular to each other, and a hatched circle indicates the position of the lamp wick28. In the positioning process, the lamp wick28is shifted from an initial position I1to a target position I3corresponding to a center C of the integration rod24. According to this embodiment, since the first direction P of the lamp holder16is substantially parallel with one side24aof the light incident surface of the integration rod24, only two steps are needed to let the lamp wick28approach the center C of the integration rod24. In the first step, the lamp wick28in an initial position (such as position I1) is shifted in the first direction P by the first positioning mechanism18to a position I2corresponding to an intersection of the first direction P and the rotation direction Q. In the second step, the lamp holder16rotates along the rotation direction Q about the axis parallel to the first direction P by the second positioning mechanism22, so the lamp wick28in the position I2corresponding to the intersection is shifted to a target position I3corresponding to the center C of the integration rod24. Hence, no matter which position the lamp wick28locates, optimum projection brightness is obtained simply by adjusting the position once along the first direction P and further adjusting the position once along the rotation direction Q. Hence, the lamp positioning process is simplified, consumption of time of the lamp positioning process is reduced, and high positioning accuracy is also achieved.

Referring toFIG. 6, the embodiment shown inFIG. 6is similar to the embodiment shown inFIG. 2, except the second positioning mechanism22further includes a pressing plate223and a fixed spring224. In this embodiment, the pressing plate223has a U-shaped cross-section, and the pressing plate223presses against the bottom of the biased protrusion structure221and is inserted into the second through hole123to prevent the biased protrusion structure221from slipping off the base plate12. The fixed spring224is disposed between the biased protrusion structure221and the pressing plate223to increase the friction between the biased protrusion structure221and the pressing plate223. The fixed spring224may avoid bad influences on the positioning accuracy in case the biased protrusion structure221vibrates as external forces being applied on the biased protrusion structure221. Besides, in this embodiment, the lamp holder16is provided with at least one third screw hole161, and the base plate12is provided with at least one fourth screw hole124, the position of the at least one fourth screw hole124corresponds to the position of the at least one third screw hole161. In one embodiment, after the position adjusting process is done by the first positioning mechanism18and the second positioning mechanism22, a second fastening screw32is inserted into the third screw hole161and the fourth screw hole124to fix the lamp holder16on the base plate12.