Scanning optical system having a tilting correcting function

Claim 2

A compact scanning optical system for scanning a surface, said system comprising: means for supplying a scanning light beam; deflecting means having a deflecting and reflecting surface for deflecting the light beam from said supply means in a predetermined direction toward the surface to be scanned; first optical means for linearly forming the light beam from said supply means near said deflecting and reflecting surface of said deflecting means; and a single toric lens disposed between said deflecting means and the surface to be scanned, said single toric lens having a power both in the deflection plane of the light beam as deflected by said deflecting means and in a plane orthogonal to said deflection plane and having different powers in orthogonal planes, said single toric lens further having a meniscus shape with its concave surface, in a cross section containing the optical axis and perpendicular to the deflection plane, facing said deflecting means, said meniscus shape further comprising a surface having a positive refractive power, the light beam deflected by said deflecting means being imaged by said single toric lens on the surface to be scanned.

Claim 3

A scanning optical system according to claim 1, wherein in a cross section containing the optical axis and parallel to the deflection plane, said single toric lens has radii of curvature r 13 and r 14 in succession from the side of said deflecting means and, in a cross section containing the optical axis and perpendicular to the deflection plane, said single toric lens has radii of curvature r 13 and r 14 in succession from the side of said deflecting means, said radii of curvature being in the following relation: |r.sub.13 |<|r.sub.13 | |r.sub.14 |<|r.sub.14 |

Claim 4

A scanning optical system according to claim 1, wherein said single toric lens is formed of plastic.

Claim 5

A scanning optical system according to claim 1, wherein in the deflection plane containing the optical axis, said single toric lens has a plano-convex shape having its convex surface facing the surface to be scanned.

Claim 6

A scanning optical system according to claim 1, wherein in the deflection plane containing the optical axis, said single toric lens has a double convex shape.

Claim 7

A scanning optical system according to claim 1, wherein in the deflection plane containing the optical axis, said single toric lens has a meniscus shape having its convex surface facing the surface to be scanned.

Claim 8

A scanning optical system according to claim 1, wherein in the cross section containing the optical axis and perpendicular to the deflection plane, the absolute value of the radius of curvature of that side of said single toric lens which is adjacent to said deflecting means is greater than the absolute value of the radius of curvature of that side of said single toric lens which is adjacent to the surface to be scanned.

Claim 9

A scanning optical system according to claim 1, wherein said single toric lens has, in a cross section containing the optical axis and orthogonal to the deflection plane, at least one surface having a negative power.

Claim 10

A compact scanning optical system for scanning a surface, said system comprising: means for supplying a scanning light beam; deflecting means having a deflecting and reflecting surface for deflecting the light beam from said supply means in a predetermined direction toward the surface to be scanned; first optical means for linearly forming the light beam from said supply means near said deflecting and reflecting surface of said deflecting means; means for moving said first optical means in the direction of the optical axis; and second optical means disposed between said deflecting means and a surface to be scanned for condensing onto the surface to be scanned the light beam deflected by said deflecting means, said second optical means consisting of a single toric lens.

Claim 11

A compact scanning optical system for scanning a surface, said system comprising: means for supplying a scanning light beam; deflecting means having a deflecting and reflecting surface for deflecting the light beam from said supply means in a predetermined direction toward the surface to be scanned; first optical means for linearly forming the light beam from said supply means near said deflecting and reflecting surface of said deflecting means; means for moving said first optical means in the direction of the optical axis; and second optical means disposed between said deflecting means and a surface to be scanned for condensing onto the surface to be scanned the light beam deflected by said deflecting means, said second optical means consisting of a single toric lens.

Claim 12

A compact scanning optical system for scanning a surface, said system comprising: a light source portion for supplying a collimated light beam of a single wavelength; a deflector for deflecting the light beam from said light source portion in a predetermined direction toward the surface to be scanned; a first imaging optical system for linearly forming, from the light beam supplied by said light source portion, a light beam component in a direction perpendicular to the deflection plane of the light beam as deflected by said deflector near said deflecting and reflecting surface of said deflector; and a single toric lens disposed between said deflector and the surface to be scanned for condensing onto the deflection plane the light beam deflected by said deflector, said single toric lens being operative to maintain, in a plane perpendicular to said deflection plane, said deflecting and reflecting surface of said deflector and the surface to be scanned in an optically conjugate relation, said single toric lens, in a plane parallel to said deflection plane, further having a value of distortion for causing the light beam deflected bv said deflector to move at a uniform speed on the surface to be scanned.

Claim 13

A compact scanning optical system for scanning a surface, said system comprising: a light source portion for supplying a collimated light beam of a single wavelength; a deflector for deflecting the light beam from said light source portion in a predetermined direction toward the surface to be scanned; a first imaging optical system for linearly forming, from the light beam supplied by said light source portion, a light beam component in a direction perpendicular to the deflection plane of the light beam as deflected by said deflector near said deflecting and reflecting surface of said deflector; and a single toric lens disposed between said deflector and the surface to be scanned for condensing onto the deflection plane the light beam deflected by said deflector, said single toric lens being operative to maintain, in a plane perpendicular to said deflection plane, said deflecting and reflecting surface of said deflector and the surface to be scanned in an optically conjugate relation, said single toric lens, in a plane parallel to said deflection plane, further having a value of distortion for causing the light beam deflected bv said deflector to move at a uniform speed on the surface to be scanned.