Optical scanning device
AssigneeKoninklijke Philips Electronics N.V.
InventorsPetrus Theodorus Jutte, Peter Coops, Joris Jan Vrehen
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Abstract
An optical scanning device for scanning a recordable optical disk (20) with a laser beam having a linear polarisation. A quarter wave plate (16) is used to alter the polarisation of the beam on reflection from the disk. A partially polarising beam splitter (8) is used and arranged such that a proportion of intensity of the incident beam passed is greater than a proportion of intensity of the reflected beam. A relatively high optical signal power at the disk (20) can be achieved for recording purposes whilst allowing the beam splitter (8) to be manufactured in a relatively efficient manner.
Claims16
An optical scanning device for scanning an optical record carrier, said device comprising a radiation source for emitting an incident radiation beam comprising a predetermined wavelength at a substantially linear polarisation, a reflective element located in the path of the incident radiation beam from the radiation source to the location of said optical record carrier and arranged to pass a first proportion, of the incident beam intensity which is incident upon the reflective element, towards the optical record carrier, a polarisation-altering element located in the path of the radiation beam from the reflective element to the location of said optical record carrier, and a detector for detecting a radiation beam reflected from said optical record carrier and passing along a path including the polarisation-altering element and the reflective element, the reflective element being arranged to pass a second proportion, of the reflected beam intensity incident upon the reflective element, towards the detector, the polarisation-altering element converting a linear polarisation of said incident beam into a substantially circular polarisation such that the incident and reflected beam have a different polarisation before and after passing through said polarisation-altering element respectively, characterised in that said reflective element is a partially polarising reflective element arranged such that said first proportion of intensity is greater, as a proportion, than said second proportion of intensity.
Dependencies are inferred from the claim text.