Optical storage medium drive apparatus

Claim 2

An optical storage medium drive apparatus for recording information on an optical storage medium (10) and reading out recorded information from said storage medium by using a light beam, comprising: an optical head (4) having a light source (4a) for emitting a light beam and a light detector (4d) for converting an optical signal into an electric signal; an optical system (4b, 4c, 2, 1, 5) for guiding said light beam from said light source to said optical storage medium and a reflected light beam from said optical storage medium to said light detector, said optical system having therein a light reflector (2) for changing direction of light beam; and optical phase compensation means (100) disposed on an optical path between said optical head and said optical storage medium for compensating for retardation of light beam caused by said reflector.

Claim 3

Apparatus according to claim 1, wherein said optical phase compensation (100) means comprises a phase shifter made of crystal having birefringence property.

Claim 4

Apparatus according to claim l, wherein said optical phase compensation means (100) comprises reflection means (Figure 8) which is in a position turned by 90 around the optical path relative to said light reflector.

Claim 5

Apparatus according to claim 1, 2 or 3, wherein said light reflector (2) comprises a total reflection prism.

Claim 6

Apparatus according to claim 4, wherein said optical phase compensation means (100) is placed on an incident surface of said total reflection prism (2).

Claim 7

Apparatus according to any one of claims 1 to 4, wherein said optical phase compensation means comprises a thin metal film provided on a reflection surface of said reflection means.

Claim 8

Apparatus according to any one of the preceding claims, and comprising a swing arm (6) turnable about an axis coincident with an optical path from said optical head; the optical system (4) being mounted on said swing arm (6).

Claim 9

An optical storage medium drive apparatus for recording information on an optical storage medium (10) and reading out recorded information from said storage medium by using a light beam, comprising: an optical head (4) having a light source (4a) for emitting a light beam and a light detector (4d) for converting an optical signal into an electric signal; a swing arm (6) turnable about an axis coincident with an optical path from said optical head; a first reflector (2b) mounted on said swing arm (6) to be placed on said axis and inclined by about 45 0 relative to said optical path from said optical head so that said light beam from said light source (4a) is reflected to a direction along the longitudinal direction of said swing arm (6); a second reflector (2a) mounted on said swing arm (6) near a free end of said swing arm and inclined by about 45 0 relative to an optical path along the longitudinal direction of said swing arm so that said light beam from said first reflector (2b) is reflected to a direction parallel to said optical path from said optical head (4) to said first reflector (2b); a focus lens (1) mounted on said swing arm (6) so as to focus the light beam reflected from said second reflector (2a) onto a surface of said optical storage medium (10); and optical phase compensation means (100) disposed on the optical path between said optical head (4) and said focus lens (1) for compensating a retardation caused by said first and second reflectors (2b, 2a).

Claim 10

An optical storage medium drive apparatus for recording information on an optical storage medium (10) and reading out recorded information from said storage medium by using a light beam, comprising: an optical head (4) having a light source (4a) for emitting a light beam and a light detector (4d) for converting an optical signal into an electric signal; a swing arm (6) turnable about an axis coincident with an optical path from said optical head; a first reflector (2b) mounted on said swing arm (6) to be placed on said axis and inclined by about 45 0 relative to said optical path from said optical head so that said light beam from said light source (4a) is reflected to a direction along the longitudinal direction of said swing arm (6); a second reflector (2a) mounted on said swing arm (6) near a free end of said swing arm and inclined by about 45 0 relative to an optical path along the longitudinal direction of said swing arm so that said light beam from said first reflector (2b) is reflected to a direction parallel to said optical path from said optical head (4) to said first reflector (2b); a focus lens (1) mounted on said swing arm (6) so as to focus the light beam reflected from said second reflector (2a) onto a surface of said optical storage medium (10); and optical phase compensation means (100) disposed on the optical path between said optical head (4) and said focus lens (1) for compensating a retardation caused by said first and second reflectors (2b, 2a).

Claim 11

Apparatus according to claim 8, wherein said optical phase compensation means (100) comprises a phase shifter made of crystal having birefringence property.

Claim 12

Apparatus according to claim 8, wherein said optical phase compensation means (Fig. 8) comprises a third reflector (2c) which is in a position turned by 90 0 around the optical path between said first and third reflectors for compensating a retardation caused by said first reflector, and a fourth reflector (2d) which is in a position turned by 90 0 around the optical path between said second and fourth reflectors for compensating a retardation caused by said second reflector.

Claim 13

Apparatus according to claims 8, 9 or 10, wherein said first and second reflectors (2b, 2a) comprise a total reflection prism.