Patent attributes
A light tunnel includes a first optical element, a second optical element, a third optical element and a fourth optical element. The first optical element has a first recess. The second optical element is disposed opposite to the first optical element and has a second recess. The third optical element connects the first optical element with the second optical element and has one end disposed in the first recess or the second recess. The fourth optical element is disposed opposite to the third optical element, connects the first optical element with the second optical element, and has one end disposed in the first recess or the second recess. Inner surfaces of the first to fourth optical elements form a light passage. A projection system is also disclosed.
