Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
71 words
An objective lens (8) having at least two regions (8a, 8b) of different numerical apertures and configured for focusing a light beam outgoing from a light source (11) as light beams transmitted through said regions (8a, 8b) of the different numerical apertures on signal recording surfaces (1a, 2a) of at least two optical discs (1, 2) having light transmitting layers (1c, 2c) of different thicknesses (t 1 , t 2 ).
Claim 2
Dependent Claim
55 words
The objective lens (8) as claimed in claim 1, wherein said regions (8a, 8b) thereof have numerical apertures of focusing the light beam outgoing from the light source for optical discs (1, 2) having the light transmitting layers (1c, 2c) with the thicknesses (t 1 , t 2 ) of 1.2 mm or 0.6 mm.
Claim 3
Dependent Claim
44 words
The objective lens (8) as claimed in claim 1, having the regions (8a, 8b) with different numerical apertures in the radial direction, with a radially inner portion (8a) of the objective lens being higher in numerical aperture than a radially outer portion (8b) thereof.
Claim 4
Dependent Claim
163 words
An optical head device (3) comprising: a light source (11) radiating a light beam; light beam separating means (13) for separating an outgoing light from said light source (11) and a return light from an optical disc (1/2); an objective lens (8) arranged between said light beam separating means (13) and said optical disc (1/2), said objective lens (8) having at least two regions (8a, 8b) of different numerical apertures and configured for focusing a light beam outgoing from the light source as light beams transmitted through said regions (8a, 8b) of the different numerical apertures on signal recording surfaces (1a/2a) of at least two optical discs (1, 2) having light transmitting layers (1c, 2c) of different thicknesses (t 1 , t 2 ); and photo-electric conversion means (16) for receiving the reflected light beams from signal surfaces (1a, 2a) of at least two optical discs (1, 2) separated by said separating means (13) for converting the reflected light beams into electrical signals.
Claim 5
Dependent Claim
63 words
The optical head device (3) as claimed in claim 4, wherein the regions (8a, 8b) of said objective lens (8) are of the numerical apertures of focusing the light beam outgoing from the light source on said optical discs (1, 2) having the light transmitting layers (1c, 2c) with the thicknesses (t 1 , t 2 ) of 1.2 mm or 0.6 mm.
Claim 6
Dependent Claim
50 words
The optical head device (3) as claimed in claim 4, wherein said objective lens (8) has the regions (8a, 8b) with different numerical apertures in the radial direction, with a radially inner portion (8a) of the objective lens being higher in numerical aperture than a radially outer portion (8b) thereof.
Claim 7
Dependent Claim
148 words
An optical disc reproducing apparatus comprising: an optical head portion (3) for radiating a light beam on a signal recording surface (1a/2a) of an optical disc (1/2) and for receiving the light beam reflected by the signal recording surface for converting the received light beam into electrical signals; and reproducing means for reproducing information signals recorded on said signal recording surface (1a/2a) based upon an output of said optical head portion (3); said head portion (3) having an objective lens (8) having at least two regions (8a, 8b) of different numerical apertures and configured for focusing a light beam outgoing from a light source (11) as light beams transmitted through said regions (8a, 8b) of the different numerical apertures on signal recording surfaces (1a, 2a) of at least two optical discs (1, 2) having light transmitting layers (1c, 2c) of different thicknesses (t 1 , t 2 ).
Claim 8
Dependent Claim
45 words
The optical disc reproducing apparatus as claimed in claim 7, wherein said reproducing means reproduces said electrical signals corresponding to the reflected light beams from the signal recording surfaces (1a, 2a) of at least two optical discs (1, 2) detected by said optical head (3).