PORTABLE SMALL-SIZED PROJECTION APPARATUS FOR READING MICROFICHES Russian patent published in 2008 - IPC G03B21/10 G02B27/18 H04N5/74 

FIELD: optical engineering.

SUBSTANCE: portable small-sized projection apparatus for reading microfiches has the following members mounted along optical axis: light source with reflecting mirror, first and second lenses of condenser, rotary mirror, third condenser's lens, first and second glass clamping plates, projection lens, swinging mirror, screen for observation, and device for shifting microfiches. Slit heat filter is mounted between second condenser's lens and rotary mirror. Acoustic-optical deflector and forming lens of acoustic-optical deflector are mounted between third lens of condenser and first clamping glass plate. Electron switch, ultrasonic oscillator and control device are introduced into device additionally to be related one to other. Acoustic-optical deflector is made in form of 8-faced optical transparent prism; it has 4 piezo-electric converters, which converters are connected with ultrasonic oscillator through switch is such a manner that frames at microfiche are scanned in horizontal plane along two mutual perpendicular directions and along diagonal directions. Projection lenses have minimal resolution of 100 lines per mm.

EFFECT: improved quality of image; reduced number of mechanical shifts of microfiches in horizontal plane.

6 dwg