Aufzeichnungstraeger aus Material zum Erzeugen und Loeschen von Lichtfarben und Verfahren zur Aufzeichnung

摘要

1,236,424. Photochromic materials and uses thereof. CANON K.K. 15 Feb., 1968 [20 Feb., 1967; 31 May, 1967; 19 June, 1967; 2 Aug., 1967; 16 Aug., 1967], No. 32493/70. Divided out of 1,236,421. Addition to 1,236,421. Heading C4S. [Also in Division G2] A projection system comprises a photochromic screen, a projector, and means for illuminating the whole screen with light of insufficient intensity to eliminate a colour image, formed by stimulation of light wherein the screen is a recording member as in claim 1 of the parent Specification. Photochromic material includes material coloured under U.V. or thermal radiation and also naturally coloured material losing colour under characteristic wavelength radiation. Many photochromic compounds are instanced including spirans, anils, and semicarbazones and may be dispersed, with a stabilizer, in a matrix containing a filmforming material on a base of resin, glass, metal, paper, fibre, wood, porcelain, or woven cloth. Many solvents and film forming materials (e.g. condensate type polymers, and homopolymers) are instanced and may shift the absorption spectrum wavelength as referred to in codivisional Specification 1,236,423. Positive and negative images may be obtained from positive and negative transparencies and the material provides an after image so that continuous projection is not necessary. In Fig. 1 (not shown), screen (16) comprises 1,3,3-trimethylindolino- 61-nitrobenzopyrylspiran in toluene, and U.V. light proceeds from visible light cut out filter (12) ahead of mercury lamp (11) and adjacent negative slide (13). Visible light from lamp (11) may hasten elimination. In Fig. 2, all screen (26) is colour developed by light sources 27, with visible light cut-out filters 28 in front of or behind the screen when translucent. Visible light from tungsten lamp 21 is projected through positive slide 23, and U.V. radiation alone may erase. In Fig. 3 (not shown), 1,3,3-trimethylindolino- 81-carboxybenzopyrylspiran and a stabilizer are dissolved in water and added to an aqueous P.V.A. solution and coated on cotton. Elimination may be by U.V. and/or intense visible radiation and the projection source may be a W or Hg lamp (31).