Disk and disk reproducing method

摘要: PURPOSE: To reproduce the optical disk recorded at a density higher than that according to standard format. CONSTITUTION: The beam having wavelength of 695nm and emitted from semiconductor laser 1 is converged applied recording track 8 with four times as dense one prescribed in format, using an objective lens 7 number aperture 0.6. reflected light split by splitter 4 led photoreceptor element 12 output photoelectrically converted signal. As for be reproduced some specifications such which pitch about half pit length more or contrarily larger one.