Auto-focus SLR camera - has mirror fitted with laser diodes for focussing on any sector in field of view

摘要

Twelve laser diodes are fitted in a 3 x 4 grid pattern on the reflex mirror (5) and coupled to a common focussing receiver (7) and amplifier. The shutter control is partially depressed to activate the focussing mechanism. It can then be moved in 4 horizontal directions. This movement selects whcih diode in the grid, and therfore whicpart in the frame will be focussed on the film plune by selecting the specific diode output as focussing signal to be processed by the receiver (7). This focussing information is displayed in the viewfinder by means of a liquid crystal element (10) with Fresnel rings driven by feedback from the focussing amplifier through a prism (11). The relative size of the frame sector selected as focussing area can be adjusted by programming a memory which can increas or decrease the number of diodes in the grid transmitting the focussing signal.