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AssigneeAsahi Glass Company, Limited
InventorsYuzuru Tanabe, Tomoki Gunjima, Hiromasa Sato, Hiroki Hotaka
Estimating the term…
An object is to provide an optical head device whereby the light utilization efficiency can be increased and which can be produced at a low cost. A glass substrate 1 having projections and recesses 2 formed by patterning a SiON type transparent thin film on its inner surface by dry etching, and a second glass substrate 3 having a polyimide film 4 formed as an alignment film on its inner surface, are laminated with a space, the periphery is sealed by a sealing material made of an epoxy resin 5, and liquid crystal 6 is injected under vacuum into the interior to form an optically anisotropic diffraction grating. On the outer surface of this second glass substrate 3, a quarter-wave film 7 is laminated, and a third glass substrate 9 is bonded by a photopolymer 8 to obtain a diffracting element 10. This diffracting element 10 is disposed between a light source and an optical recording medium to obtain an optical head device.
An optical head device whereby writing of information and/or reading out of information is carried out by irradiating an optical recording medium with light from a light source, through a diffracting element, wherein the diffracting element is provided with an optically anisotropic diffraction grating having lattice-like projections and recesses formed on the surface of a transparent substrate, and said projections and recesses are filled with a liquid crystal having an optical anisotropy, and at least the projections among the projections and recesses are formed by a transparent thin film made of SiOxNy (0≦x<2, 0≦y<1.3), provided on the surface of the transparent substrate, which employs a diffracting element wherein at least the projections among the projections and recesses are substantially equal to the ordinary refractive index or extraordinary refractive index of the liquid crystal.
An optical head device whereby writing of information and/or reading out of information is carried out by irradiating an optical recording medium with light from a light source, through a diffracting element, wherein the diffracting element is provided with an optically anisotropic diffraction grating having lattice-like projections and recesses formed on the surface of a transparent substrate, and said projections and recesses are filled with a liquid crystal having an optical anisotropy, and at least the projections among the projections and recesses are formed by a transparent thin film made of SiOxNy (0≦x<2, 0≦y<1.3), provided on the surface of the transparent substrate, wherein a phase difference element is laminated on the liquid crystal side of the optically anisotropic diffraction grating to constitute the diffracting element, the phase difference element being a phase difference sheet or phase difference film, at least one side of which is covered by an organic resin, and the phase difference sheet or phase difference film being sandwiched with transparent flat substrates.
Dependencies are inferred from the claim text.