Phase-only spatial light modulator having high reflectance, high-definition pixels and high photo-durability

We developed phase-only spatial light modulator (SLM) with high reflectance, high-definition pixels, and high photo-durability based on liquid crystal on silicon (LCOS) technology for projectors. We have been improved LCOS technology to realize high image quality such as high contrast and high resolution, and to obtain high reliability against high energy of light for the projector application, over the past several decades. As a result, we established high reflectance technology, high-definition pixel technology, and high photo-durability technology. If we apply these technologies to SLM, the high reflectance realizes the high light-use efficiency, the high-definition pixels expand the diffraction angle, and the high photo-durability enables the use of a high-power laser. Based on these technologies, we have developed a phase-only SLM with 4.25-mu m pixel pitch. In this paper, the details of the high reflectance technology, the high definition pixel technology and the high photo-durability technology are explained. Design requirements for phase-only SLM are also discussed. In addition, the laser soldering machine is proposed as an application example of our phase-only SLM.