[Polarization conversion element]

Light is a type of electromagnetic wave that polarizes light with a specific direction of vibration. It's called. In particular, linearly polarized light oscillating in a plane including the optical axis is Depending on the direction of vibration, it is called P or S polarized light and exhibits different properties.

Light emitted from common light sources (incandescent lamps, mercury lamps, etc.) is unpolarized The P polarization component and the S polarization component are present in the same ratio. However, in optical equipment, only one of P-polarized light and S-polarized light is used. There is something to use, and if one polarization is selected by a polarizing plate etc. The light intensity will be halved.

The polarization conversion element is a P-polarized or An optical element that converts to S-polarized light.

Principle of PCS

The figure on the left is an example of converting non-polarized light to P-polarized light. The incident non-polarized light is transmitted by the P-polarized light through the polarization separation film, S-polarized light is reflected. The reflected S-polarized light is reflected by the reflective film. After the course is bent 90 ° again, the phase difference plate (1/2 wavelength plate) Is converted to P-polarized light. In this way, the light separated into the two optical paths becomes P-polarized light. Become.

Change the phase difference plate to the transmission optical path (incident optical axis) Therefore, it can be converted to S-polarized light.