US Patent 7411884 Optical system with objective lens having diffraction structure
Patent 7411884 was granted and assigned to Hoya on August, 2008 by the United States Patent and Trademark Office.
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An optical system for an optical disc drive includes a light source, an objective lens and a collimator lens. The light source emits first and second light beams. The first light beam is for reproducing data from a digital versatile disc while the second light beam is for a compact disc. The objective lens is provided with a diffraction structure which is designed to focus the first light beam on a recording layer of the digital versatile disc and the second light beam on a recording layer of the compact disc. The collimator lens is disposed between the light source and the objective lens. The collimator lens adjusts the diverging/converging angle of the first and second light beams entering the objective lens. The change in spherical aberration of the first light beam caused by wavelength deviation from a design wavelength due to individual specificity of the light source is corrected by adjusting the diverging/converging angle of the first light beam emerging from the collimator lens.
US Patent 07411884 Optical system with objective lens having diffraction structure US Patent 7411884 Optical system with objective lens having diffraction structure
US Patent 07411884 Optical system with objective lens having diffraction structure
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