Surface profile measuring apparatus
A surface profile measuring apparatus includes a light source assembly, a spatial light modulator, a spectroscope, a wave-front sensor, and a control-processing device. The light source assembly has a liquid crystal display pixel structure and is configured for providing parallel light. The spatial light modulator is positioned to receive the light from the light source assembly. The spectroscope is positioned to receive the light from the spatial light modulator. The wave-front sensor is positioned to receive the light from the spectroscope. The control-processing device is electrically connected to the spatial light modulator and the wave-front sensor. The surface profile measuring apparatus can measure the surface profile of an object and not contact the surface of the object in cooperation with the spatial light modulator, the spectroscope and the wave-front sensor. Therefore, the surface of the object is protected from being damaged.
1. A surface profile measuring apparatus for measuring a surface profile of an object, comprising:
a light source assembly configured for providing parallel light;
a spatial light modulator having a liquid crystal display pixel structure and positioned to receive the light from the light source assembly, the liquid crystal display pixel structure comprising a plurality of pixel cells;
a spectroscope for being positioned between the spatial light modulator and the object, the spectroscope being configured for transmitting the light from the spatial light modulator and reflecting the light from the object;
a wave-front sensor positioned to receive the light reflected from the spectroscope and configured for acquiring a wave-front slope value of the light corresponding to each pixel of the spatial light modulator; and
a control-processing device electrically connected to the spatial light modulator and the wave-front sensor and configured for controlling turn-on/turn-off of each of pixel cells of the spatial light modulator to transmit/reflect the light and processing the wave-front slope value output from the wave-front sensor to acquire the surface profile of the object.
2. The surface profile measuring apparatus as claimed in claim 1 , wherein the light source assembly comprises a light source for emitting diverging non-polarizing white light, a collimating lens positioned to receive the light from the light source, and a polarization converter positioned to receive the light from the collimating lens, the collimating lens configured for converting the diverging light emitted from the light source into the parallel light, the polarization converter configured for converting the non-polarized white light output from the collimating lens into a polarized light having single polarization.
3. The surface profile measuring apparatus as claimed in claim 1 , wherein the spectroscope comprises a polarizing beam splitter and a retarder disposed between the polarizing beam splitter and the object.
4. The surface profile measuring apparatus as claimed in claim 3 , wherein the polarizing beam splitter is a wire grid polarizer.
5. The surface profile measuring apparatus as claimed in claim 3 , wherein the polarizing beam splitter is a polarizing beam splitter prism.
6. The surface profile measuring apparatus as claimed in claim 1 , wherein the wave-front sensor is a Shack-Hartman wave-front sensor.
7. The surface profile measuring apparatus as claimed in claim 1 , wherein the wave-front sensor comprises a micro-lens array and an image sensor positioned to receive the light from the micro-lens array.