JPS5472005A - Record player - Google Patents

Abstract

PURPOSE: To make photo detector one and achieve the simplification of constitution and the considerable reduction in cost by providing plural through-holes and plural photoconductive members according to the size of records to the turntable and letting the photoconductive members approach to the common photo detector.

CONSTITUTION: When a turntable 1 rotates where on record disc is placed, light is radiated to a photo detector 9 each time when all the through-holes 3 thru 5 pass above photoconductive members 10 thru 12. The pulse signals corresponding to these are then obtained from the element 9. In this case, the respective sets of the throughholes 3₁, 4₁, 5₁.4₂, 5₃.3₂, 4₃, 5₅.5₇ are disposed on one row on the same radius and therefore the element 9 produces one pulse when each set passes above the members 10 thru 12, thus 8 pulse signals are obtained by one rotation of the table 1. When a record disc of 17 cm is placed, the through- holes 5₁ thru 5₈ are covered and four pulses are obtained from the element 9 with respect to one rotation of the table 1. In this way, the record discs may be discriminated with one photo detector and therefore, the simplification of constitution and the reduction of cost may be achieved.

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