Abstract: A lighting module includes a lighting unit, a cylindrical optical element, a supporting unit, and a base. The supporting unit connects the base and a part of the supporting unit is higher than a junction of the base and the supporting unit. The lighting unit is disposed on the base and includes a lighting surface emitting a light beam. The cylindrical optical element includes an incident surface and both ends of the cylindrical optical element are respectively connected to the supporting unit making the incident surface facing the lighting surface and having an interval from the lighting unit to the incident surface, and the light beam enters the cylindrical optical element from the incident surface. The lighting module satisfies the following condition: 2?D/E?6; wherein D is a diameter of the cylindrical optical element and E is the interval from the lighting unit to the incident surface.

Abstract: An optical device and the prism module thereof are provided. The prism module includes a first prism, a second prism, and a third prism. The second prism is disposed beside the first prism. The third prism is adhered to the second prism. First light enters the first prism, is reflected plural times in the first prism, enters the second prism, and is emitted from the second prism. Second light enters the second prism, is reflected plural times in the second prism, and is emitted from the second prism. Third light sequentially passes through the third prism and the second prism, enters the first prism, is reflected plural times in the first prism, and is emitted from the first prism.

Abstract: An optical device and the prism module thereof are provided. The prism module includes a first prism, a second prism, and a third prism. The second prism is disposed beside the first prism. The third prism is adhered to the second prism. First light enters the first prism, is reflected plural times in the first prism, enters the second prism, and is emitted from the second prism. Second light enters the second prism, is reflected plural times in the second prism, and is emitted from the second prism. Third light sequentially passes through the third prism and the second prism, enters the first prism, is reflected plural times in the first prism, and is emitted from the first prism.