Light-emitting diodes (LED) have many advantages for dental astral lighting because of their high color rendering index (CRI), low power consumption, light weight and longer life. A dental astral lamp is specially designed and simulated for securing the extra space for installing a multimedia display that will be helpful for treating young patients. The optical system using the reverse dual reflection method consisted of four illumination modules disposed at the four corners of the dental astral lamp, and each module comprises a high power LED, an elliptical mirror, and a multifacet reflector assembly using eight cylindrical mirrors. It is shown that the required illuminance, illumination pattern, and the illumination uniformity are well satisfied.
A TTL(through-the-lens) alignment system using the holographic phase conjugation in photopolyrner films for application to ArF step-and-scan exposure system was designed, and the TTL alignment signals were obtained. The optical setup is similar to the DFWM(degenerate four-wave mixing). The recording materials were HRF 150 photopolymer films of Du Pont corporation, and the recording wavelength was 476 nm of argon ion laser with 400mW output power. The diffraction efficiencies of photopolymer film were typically around 50%. Fine patterns as small as imicron were imaged successfully by the phase conjugate waves generated by DFWM holography. For TTL alignment, the 'X' or chevron patterns ofthe 1 or 2 micron linewidths were recorded as hologram and the reconstructed phase conjugate beams were used as the align beam through the projection lens which has strong chromatic aberration. TTL alignment signals were obtained by scanning the wafer with alignment mark under the align beam.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.