| 摘要 |
1,271,437. Holography. NIPPON ELECTRIC CO. Ltd. Nov.14, 1969 [Nov.27, 1968], No. 55946/69. Heading G2J. [Also in Division C4] A matrix 2 comprises rows and columns of holograms each formed by interference between a coherent reference beam 19 and a selected combination of coherent object beams representative of a binary code defining the co-ordinates of an elementary area of the matrix. Illumination of the matrix 1 by a reconstructing coherent beam perpendicular to the hologram plate gives rise to an undiffracted component 47, Fig. 3, and a first order diffraction component 48 reforming an image which is detected by means 38-41, Fig. 3, which convert the image into a parallel binary signal which reproduces the code of the elementary area. The reconstructing light beam is transmitted by a flexible light guide 26 moved by hand across the hologram matrix to give the desired trace. The undiffracted component is used to give a visual display of the trace. For this the source 20 of the light pen generates red or near infrared light rays which illuminate a photo-chromic plate 35 back-illuminated with ultraviolet light. An ultraviolet filter 34 is located in the undiffracted beam path 47 between the matrix 1 and photochromic plate 35. The binary coded signal produced may be used as data feed for a computer. |
