OPTICAL SCANNING DEVICE

• Main Authors: ITO TATSUO, MATSUNAMI TAKAO
• Format: Patent
• Language: English
• Published: 14.02.1992
• Subjects: DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

PURPOSE:To correct the influence of variation in the wavelength of a semiconductor laser over the entire range by installing an acoustooptic element between the laser light source and a hologram and composing the hologram of plural holograms which have correction effect in different wavelength ranges. CONSTITUTION:Basic constitution wherein diffraction is performed plural times by the acoustooptic element 7 and a hologram disk 8 to cancel the influence of the diffraction is realized and the hologram disk 8 has plural hologram zones 8a, 8b, and 8c, which function for the scanning of laser beams in different narrow wavelength ranges. Further, when variation in the wavelength of the laser beam exceeds a set wavelength range of one hologram zone, the laser beam is made incident on a hologram zone designed corresponding to an adjacent wavelength range by angular modulation by varying the high frequency wavelength of the acoustooptic element 7. The number of the hologram zones and the range of the angular modulation are set properly to cover the entire wavelength variation range of the laser light source 6.