Abstract: An optical touch system includes a non-visible light source, a screen, a first and second polarizing elements, and an optical detector. The non-visible light source emits a non-visible beam. A part of the non-visible beam passes through the screen disposed in a light path of the non-visible beam. The touch object reflects the part of the non-visible beam into an object beam when a touch object approaches or touches the screen, and the object beam passes through the screen. The first polarizing element is disposed in the light path of the non-visible beam and between the non-visible light source and the screen. The optical detector is disposed in a light path of the object beam, and senses the object beam. The second polarizing element is disposed in the light path of the object beam passing through the screen and between the screen and the optical detector.

Abstract: An optical touch system includes a non-visible light source, a screen, a first and second polarizing elements, and an optical detector. The non-visible light source emits a non-visible beam. A part of the non-visible beam passes through the screen disposed in a light path of the non-visible beam. The touch object reflects the part of the non-visible beam into an object beam when a touch object approaches or touches the screen, and the object beam passes through the screen. The first polarizing element is disposed in the light path of the non-visible beam and between the non-visible light source and the screen. The optical detector is disposed in a light path of the object beam, and senses the object beam. The second polarizing element is disposed in the light path of the object beam passing through the screen and between the screen and the optical detector.

Abstract: A color wheel includes a fixing base, a ring filter, a washer, and a fixing ring. The fixing base has a protrusion portion and a supporting portion. The ring filter is fit on the protrusion portion. An inner margin of the ring filter leans on the supporting portion. The washer is connected to the protrusion portion. The ring filter is disposed between the washer and the supporting portion. The washer and the supporting portion clip the inner margin of the ring filter. The fixing ring has an annular supporting portion, a side wall surrounding the annular supporting portion, and fixing blocks connected to the side wall and dotted on an outer margin of the ring filter. The outer margin of the ring filter leans on the annular supporting portion. The fixing blocks, the side wall, and the annular supporting portion clip the outer margin of the ring filter.

Abstract: A color wheel includes a fixing base, a ring filter, a washer, and a fixing ring. The fixing base has a protrusion portion and a supporting portion. The ring filter is fit on the protrusion portion. An inner margin of the ring filter leans on the supporting portion. The washer is connected to the protrusion portion. The ring filter is disposed between the washer and the supporting portion. The washer and the supporting portion clip the inner margin of the ring filter. The fixing ring has an annular supporting portion, a side wall surrounding the annular supporting portion, and fixing blocks connected to the side wall and dotted on an outer margin of the ring filter. The outer margin of the ring filter leans on the annular supporting portion. The fixing blocks, the side wall, and the annular supporting portion clip the outer margin of the ring filter.