Apparatus for reading information

Claim 1

An apparatus for reading information from an optical recording medium, comprising: a laser beam source for generating a laser beam; a beam splitter; and at least one fixed mirror disposed in an optical path of said laser beam between said laser beam source and said beam splitter to reflect said laser beam toward said laser beam splitter; means for receiving said laser from said beam splitter and directing said laser beam at an optical recording medium for generating a reflected laser beam for information carrying light; means for receiving said information carrying light; said laser beam source being arranged so that a linearly polarized, light oscillating plane including an optical axis and an oscillating direction of said leaser beam is perpendicular to a plane including a normal of said fixed mirror and said optical axis of said laser beam; wherein a plane including a normal of a reflection plane of said beam splitter and said optical axis of said laser beam is parallel to said linearly polarized, light oscillating plane; said fixed mirror comprises a multi-layered, dielectric film structure formed by alternately stacking high refractive index films and low refractive index films on a glass substrate; and wherein said high refractive index films are made of zirconium oxide and said low refractive index films are made of silicon dioxide, and a number of said films is less than 14.

Claim 2

An apparatus for reading information from an optical recording medium, comprising: a laser beam source for generating a laser beam; a beam splitter; and at least one fixed mirror disposed in an optical path of said laser beam between said laser beam source and said beam splitter to reflect said laser beam toward said laser beam splitter; means for receiving said laser from said beam splitter and directing said laser beam at an optical recording medium for generating a reflected laser beam for information carrying light; means for receiving said information carrying light; said laser beam source being arranged so that a linearly polarized, light oscillating plane including an optical axis and an oscillating direction of said leaser beam is perpendicular to a plane including a normal of said fixed mirror and said optical axis of said laser beam; wherein a plane including a normal of a reflection plane of said beam splitter and said optical axis of said laser beam is parallel to said linearly polarized, light oscillating plane; said fixed mirror comprises a multi-layered, dielectric film structure formed by alternately stacking high refractive index films and low refractive index films on a glass substrate; and wherein said high refractive index films are made of zirconium oxide and said low refractive index films are made of silicon dioxide, and a number of said films is less than 14.

Claim 3

The apparatus as claimed in clam 1, further comprising a platform having two broad sides and a light receiving element; said laser beam source, said beam splitter and said fixed mirror being fixed on said platform, said light receiving element being disposed kin a facing relationship with a side of said platform opposite from a side on which said laser beam source is mounted.

Claim 4

An apparatus for reading information from an optical recording medium, comprising: a laser beam source for generating a laser beam; a beam splitter; and at least one fixed mirror disposed in an optical path of said laser beam between said laser beam source and said beam splitter to reflect said laser beam toward said laser beam splitter; means for receiving said laser from said beam splitter and directing said laser beam at an optical recording medium for generating a reflected laser beam for information carrying light; means for receiving said information carrying light; said laser beam source being arranged so that a linearly polarized, light oscillating plane including an optical axis and an oscillating direction of said laser beam is perpendicular to a plane including a normal of said fixed mirror and said optical axis of said laser beam; wherein a plane including a normal of a reflection plane of said beam splitter and said optical axis of said laser beam is parallel to said linearly polarized, light oscillating plane; said fixed mirror comprises a multi-layered, dielectric film structure formed by alternately stacking high refractive index films and low refractive index films on a glass substrate; and wherein said high refractive index films are made of zinc sulfate and said low refractive index films are made of magnesium fluoride, and a number of said films is less than 10.

Claim 5

An apparatus for reading information from an optical recording medium, comprising: a laser beam source for generating a laser beam; a beam splitter; and at least one fixed mirror disposed in an optical path of said laser beam between said laser beam source and said beam splitter to reflect said laser beam toward said laser beam splitter; means for receiving said laser from said beam splitter and directing said laser beam at an optical recording medium for generating a reflected laser beam for information carrying light; means for receiving said information carrying light; said laser beam source being arranged so that a linearly polarized, light oscillating plane including an optical axis and an oscillating direction of said laser beam is perpendicular to a plane including a normal of said fixed mirror and said optical axis of said laser beam; wherein a plane including a normal of a reflection plane of said beam splitter and said optical axis of said laser beam is parallel to said linearly polarized, light oscillating plane; said fixed mirror comprises a multi-layered, dielectric film structure formed by alternately stacking high refractive index films and low refractive index films on a glass substrate; and wherein said high refractive index films are made of zinc sulfate and said low refractive index films are made of magnesium fluoride, and a number of said films is less than 10.