Abstract An optical system for scanning a medium with a beam spot includes a light beam generator, a deflector for deflecting the light beam in a predetermined direction and in deflection plane, and an imaging optical system between the deflector and the medium for imaging the light beam from the deflector on the medium as a beam spot, the imaging optical system having at least one lens element mode of a moisture absorbing material. The lens element has a shape in which the dimension in a direction parallel to the deflection plane of the light beam is greater than the dimension in a direction perpendicular to the deflection plane of the light beam. A device mitigates any influence on the imaged condition of the light beam on the medium caused by the lens element being subjected to moisture.
An optical system for scanning a medium with a beam spot, said optical system comprising: means for supplying a light beam; means for deflecting the light beam from said light beam supplying means in a predetermined direction and in a deflection plane; means disposed between said deflecting means and said medium for imaging the light beam from said deflecting means on said medium as a beam spot, said imaging means having at least one lens element made of a moisture absorbing material the refractive index of which varies with the amount of moisture absorbed, said lens element having a shape in which the length in a direction parallel to the deflection plane of the light beam is greater than the length in a direction orthogonal to the deflection plane of the light beam; and means for mitigating the influence on the imaged condition of the light beam on the medium resulting from said lens element being subjected to moisture, said mitigating means including a moisture proof member provided only on the portion of the surface of said lens element through which the light beam does not pass.
Claim 2
Dependent Claim
187 words
An optical system for scanning a medium with a beam spot, said optical system comprising: means for supplying a light beam; means for deflecting the light beam from said light beam supplying means in a predetermined direction and in a deflection plane; means disposed between said deflecting means and said medium for imaging the light beam from said deflecting means on said medium as a beam spot, said imaging means having at least one lens element made of a moisture absorbing material the refractive index of which varies with the amount of moisture absorbed, said lens element having a shape in which the length in a direction parallel to the deflection plane of the light beam is greater than the length in a direction orthogonal to the deflection plane of the light beam; and means for mitigating the influence on the imaged condition of the light beam on the medium resulting from said lens element being subjected to moisture, said mitigating means including a moisture proof member provided only on the portion of the surface of said lens element through which the light beam does not pass.
Claim 3
Dependent Claim
15 words
An optical system according to claim 1, wherein said lens element is a plastic lens.
Claim 4
Dependent Claim
14 words
An optical system according to claim 1, wherein said moisture proof member is wax.
Claim 5
Dependent Claim
15 words
An optical system according to claim 1, wherein said moisture proof member is metal foil.
Claim 6
Dependent Claim
183 words
An optical system for scanning a medium with a beam spot, said optical system comprising: means for supplying a light beam; means for deflecting the light beam from said light beam supplying means in a predetermined direction and in a deflection plane; means disposed between said deflecting means and said medium for imaging the light beam from said deflecting means on said medium as a beam spot, said imaging means having at least one lens element having a non-lens surface and being made of a moisture absorbing material the refractive index of which varies with the amount of moisture absorbed, said lens element having a shape in which the length in a direction parallel to the deflection plane of the light beam is greater than the length in a direction orthogonal to the deflection plane of the light beam; and means for mitigating the influence on the imaged condition of the light beam on the medium resulting from said lens element being subjected to moisture, said mitigating means including a moisture proof member provided only on said non-lens surface of said lens element.
Claim 7
Dependent Claim
183 words
An optical system for scanning a medium with a beam spot, said optical system comprising: means for supplying a light beam; means for deflecting the light beam from said light beam supplying means in a predetermined direction and in a deflection plane; means disposed between said deflecting means and said medium for imaging the light beam from said deflecting means on said medium as a beam spot, said imaging means having at least one lens element having a non-lens surface and being made of a moisture absorbing material the refractive index of which varies with the amount of moisture absorbed, said lens element having a shape in which the length in a direction parallel to the deflection plane of the light beam is greater than the length in a direction orthogonal to the deflection plane of the light beam; and means for mitigating the influence on the imaged condition of the light beam on the medium resulting from said lens element being subjected to moisture, said mitigating means including a moisture proof member provided only on said non-lens surface of said lens element.