An optical apparatus is configured to introduce light from an object to an image pickup element, and includes first, second, and third retardation plates, a polarizer, and a setter. The first retardation plate, the second retardation plate, and the polarizer are arranged in this order from a side of the object to a side of the image pickup element. The slow axis direction or the fast axis direction of the second retardation plate tilts to the slow axis direction or the fast axis direction of the first retardation plate. The setter sets the retardation of the second retardation plate according to the polarization component of the light from the object.

An optical apparatus is configured to introduce light from an object to an image pickup element, and includes first, second, and third retardation plates, a polarizer, and a setter. The first retardation plate, the second retardation plate, and the polarizer are arranged in this order from a side of the object to a side of the image pickup element. The slow axis direction or the fast axis direction of the second retardation plate tilts to the slow axis direction or the fast axis direction of the first retardation plate. The setter sets the retardation of the second retardation plate according to the polarization component of the light from the object.

The present disclosure relates to an electroconductive roller for an electrophotographic printer. The roller comprises a polyurethane composition containing a polyurethane and an ionic liquid. The cation of the ionic liquid is an organic cation. The polyurethane composition has a specific resistivity of 110.sup.5 .Math.cm to 110.sup.8 .Math.cm.

The present disclosure relates to an electroconductive roller for an electrophotographic printer. The roller comprises a polyurethane composition containing a polyurethane and an ionic liquid. The cation of the ionic liquid is an organic cation. The polyurethane composition has a specific resistivity of 110.sup.5 .Math.cm to 110.sup.8 .Math.cm.

An optical apparatus is configured to introduce light from an object to an image pickup element, and includes first, second, and third retardation plates, a polarizer, and a setter. The first retardation plate, the second retardation plate, and the polarizer are arranged in this order from a side of the object to a side of the image pickup element. The slow axis direction or the fast axis direction of the second retardation plate tilts to the slow axis direction or the fast axis direction of the first retardation plate. The setter sets the retardation of the second retardation plate according to the polarization component of the light from the object.

An optical apparatus is configured to introduce light from an object to an image pickup element, and includes first, second, and third retardation plates, a polarizer, and a setter. The first retardation plate, the second retardation plate, and the polarizer are arranged in this order from a side of the object to a side of the image pickup element. The slow axis direction or the fast axis direction of the second retardation plate tilts to the slow axis direction or the fast axis direction of the first retardation plate. The setter sets the retardation of the second retardation plate according to the polarization component of the light from the object.

Provided is an apparatus including: an element in which a fine structure changing a polarization state of a light flux from a light source is formed on at least one of an incident surface or an exit surface thereof; a deflecting unit deflecting light flux that has passed through optical element to scan a scanned surface in a main scanning direction; and an optical system guiding light flux deflected by deflecting unit to scanned surface, wherein fine structure includes a plurality of protruding portions each extending in a first direction, the plurality of protruding portions being arrayed in a second direction perpendicular to first direction, and wherein the following condition is satisfied:

1/20??.sub.1/?.sub.1?1/6,

where ?.sub.1 represents a phase difference between first direction and second direction of birefringence caused by fine structure, and ?.sub.1 represents a wavelength of light flux.

Provided is an apparatus including: an element in which a fine structure changing a polarization state of a light flux from a light source is formed on at least one of an incident surface or an exit surface thereof; a deflecting unit deflecting light flux that has passed through optical element to scan a scanned surface in a main scanning direction; and an optical system guiding light flux deflected by deflecting unit to scanned surface, wherein fine structure includes a plurality of protruding portions each extending in a first direction, the plurality of protruding portions being arrayed in a second direction perpendicular to first direction, and wherein the following condition is satisfied:

1/20??.sub.1/?.sub.1?1/6,

where ?.sub.1 represents a phase difference between first direction and second direction of birefringence caused by fine structure, and ?.sub.1 represents a wavelength of light flux.

Provided is an apparatus including: an element in which a fine structure changing a polarization state of a light flux from a light source is formed on at least one of an incident surface or an exit surface thereof; a deflecting unit deflecting light flux that has passed through optical element to scan a scanned surface in a main scanning direction; and an optical system guiding light flux deflected by deflecting unit to scanned surface, wherein fine structure includes a plurality of protruding portions each extending in a first direction, the plurality of protruding portions being arrayed in a second direction perpendicular to first direction, and wherein the following condition is satisfied:
1/20.sub.1/.sub.11/6, where .sub.1 represents a phase difference between first direction and second direction of birefringence caused by fine structure, and .sub.1 represents a wavelength of light flux.

Provided is an apparatus including: an element in which a fine structure changing a polarization state of a light flux from a light source is formed on at least one of an incident surface or an exit surface thereof; a deflecting unit deflecting light flux that has passed through optical element to scan a scanned surface in a main scanning direction; and an optical system guiding light flux deflected by deflecting unit to scanned surface, wherein fine structure includes a plurality of protruding portions each extending in a first direction, the plurality of protruding portions being arrayed in a second direction perpendicular to first direction, and wherein the following condition is satisfied:
1/20.sub.1/.sub.11/6, where .sub.1 represents a phase difference between first direction and second direction of birefringence caused by fine structure, and .sub.1 represents a wavelength of light flux.