Appeal No. 2005-2750
Application 09/460,221
positions of the high-density disc and the high NA lens carried by the second optical
head.3
The optical discs are contained in respective cartridges 2. Each cartridge has a
disc thickness discrimination hole 7 whose open or closed states identifies the type (i.e.,
thickness) of disc contained therein. The open or closed state is detected using a light
emitting diode (LED) 8 and a photodiode 9. A system controller 22 is responsive to the
output of photodiode 9 to (a) use LD driving circuit 20 and selector switch 21 to activate
the laser light source in the appropriate optical head and (b) use selector switch 10 to
select the output signal from the appropriate photodetector.
Second embodiment – Figs. 5-6
The second embodiment differs from the first by including both optical systems in
a single optical head 30, as shown in detail in Figure 6.
Third embodiment – Figs. 7-8
3 Figures 4A and 4B have been amended by a certificate of correction in the
Reissue Patent to designate the focal distance FD and the working distance WD.
5
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