Method and apparatus for correcting focus in an optical recording system
AssigneeTandy Corporation
InventorJoel D. Finegan
Life of this patent
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Abstract
An optical recording system. The system is directed towards optical recording media which is responsive to at least two wavelengths of light such as an erase beam and a record beam. Light of a lower wavelength is produced by a divergent light source such as a diode and only partially collimated in a collimating lens. When the record and erase beams pass through a common objective for focusing on the recording media, the slightly divergent lower wavelength beam is focused at the same location as the fully collimated higher wavelength beam.
Claims18
A recording system for recording detectable marks on a storage media, said storage media responsive to light of at least a first wavelength, comprising:
- a) a first light source for generating said first wavelength of light;
- b) a second light source for generating a second wavelength of light, which is different from said first wavelength of light;
- c) an objective lens for focusing light from said first and said second light source;
- and
- d) a collimating lens for adjusting a focus position of light from at least one of said light sources on said recording media, said collimating lens being displaced from a first position said first position producing a fully collimated light beam from said at least one of said light sources, said light from said first and second light sources being simultaneously focused on same position of said recording media.
A method of focusing light beams from a first divergent light source and a second light source on an optical storage media with an objective lens, said first light source producing a shorter wavelength of light than said second light source, comprising the step of partially collimating light from said first light source such that light rays from said first light source enter said objective lens as diverging light rays, said light from both light sources simultaneously focusing at the same position on said optical storage media.
A method of focusing light from a first divergent light source and a second light source on an optical storage media with an objective lens, said first light source producing a longer wavelength than said second light source, comprising the step of over collimating light from said first light source such that light rays from said first light source enter said objective lens as converging rays, light from both light sources simultaneously focusing at the same position on said optical storage media.
A method of focusing light from first and second divergent light sources on an optical storage media, said first light source producing a first, longer wavelength than a second wavelength from said second source, comprising the step of collimating said first and second light sources in a collimation lens, said first light source placed at a distance from said collimation lens such that light of said first wavelength from said collimating lens is converging, light from both of said light sources simultaneously focusing at the same position on said optical storage media.
A method of focusing light from first and second divergent light sources on an optical data storage media, said first light source producing a first, shorter wavelength than a second wavelength from said second source, comprising the step of collimating light from said first and second light sources in a collimation lens, said first light source placed at a distance from said collimation lens such that light of said first wavelength from said collimation lens is diverging, light from both of said light sources simultaneously focusing at the same position on said optical data storage media.
Dependencies are inferred from the claim text.