| 摘要 |
1,267,743. Photochromism. R.C.A. CORPORATION. 13 May, 1969 [13 May, 1968], No. 24360/69. Heading C4S. [Also in Division G1] Light modulating apparatus comprises a first light source 21, means for combining components of light from this source so that interference occurs therebetween, a photochromic body 23 in the path of at least one component and means for directing light on to the photochromic body to vary its refractive index and the interference. Light from a tunable Kr laser 21 is passed through a Fabry-Porot cavity 23 of Sr titanate doped with 0.03% Fe and 0À03% Co the sides of which are A1 coated. The cavity is irradiated with a Hg arc lamp 24 to produce interference and modulate the light output which is detected by a device 26. The p.c. material is bleached by red and yellow light from the laser. The light from source 21 may be split into two beams one passing through a body of p.c. material the other through material having the same refractive index, the beams are then recombined. The device may be used in display devices wherein the photochromic material is scanned with switching light or selected areas are masked from switching light. The p.c. material may be CaF 2 doped with Ce or La, sodalite, Ca titanate doped with Mo, organic, mono- or poly-crystalline or dissolved in solution. |
