It is an object of the present invention to provide an apparatus for
discriminating an optical recording medium which can reliably
discriminate the kind of an optical recording medium even in the case
where the optical recording medium to be discriminated is warped and
formed with periodical undulation in the circumferential direction
thereof.The apparatus 10 for discriminating an optical recording medium
according to the present invention includes a first electrode 11, a
second electrode 12, a third electrode 13, a fourth electrode 14, an
alternating current signal generation circuit 17 for applying an
alternating current signal A to the first electrode 11 and the third
electrode 13, a detection circuit 18 for detecting the level of an
alternating current signal B1 appearing at the second electrode 12 and
the level of an alternating current signal B2 appearing at the fourth
electrode 14, a supporting mechanism 15 for supporting the first
electrode 11 and the second electrode 12, a supporting mechanism 16 for
supporting the third electrode 13 and the fourth electrode 14, a driving
mechanism 33 for vertically moving the supporting mechanism 15, a driving
mechanism 34 for vertically moving the supporting mechanism 16, and a
control circuit 19 for controlling the operations of the alternating
current signal generation circuit 17, the detection circuit 18, the
driving mechanism 33 and the driving mechanism 34, and a table 19a is
provided in the control circuit 19.