Liquid-crystal luminaire consisting of an optical shutter and a metal halide lamp

Kuniharu Takizawa, Takanori Fujii, Hideo Fujikake, Tsunehiro Hirabayashi, Yoshiaki Tanaka, Kohji Hara, Satoshi Takano, Hisashi Asakawa, Hiroshi Kita

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


We made a liquid-crystal (LC) luminaire for the first time to our knowledge by combining a metal halide lamp and an optical shutter composed of a compound of a very high nematic-isotropic point (172 °C) LC and a polymer (CLCP). The shutter can modulate high-power light independently of the state of polarization because the CLCP film becomes transparent or opalescent when either sufficiently high or no voltage is applied to it. To solve the problem, which is peculiar to CLCP films, that the color temperature of light modulated by the film changes with the films transmittance, a pulse-width modulation method that varies the time ratio of the on and off states of the shutter was developed. The performance characteristics of the luminaire were as follows: illuminance range, 192 to 10,400 lx at a distance of 5 m from the luminaire; rise and decay times, 1.4 and 1.5 ms; color temperature, 4060–5600 K; operation room temperature, ∼150 °C; stable operation time, more than 2000 h. Experimental results show the feasibility of applications of this luminaire in various fields, including television, movie, and stage lighting.

Original languageEnglish
Pages (from-to)2570-2578
Number of pages9
JournalApplied Optics
Issue number12
Publication statusPublished - 1999 Apr 20


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