Lens array, lens unit, LED head, exposure unit, image formation apparatus, reading apparatus, mold for molding lens array, and method for manufacturing lens array

A lens array comprising:

• a lens including a first lens surface and a second lens surface, wherein
• the first lens surface is formed to tilt at a predetermined tilt angle with respect to the second lens surface, and
• the first lens surface is formed to be eccentric by an eccentric distance in such a direction that the optical axis of the second lens surface and an optical axis of the first lens surface intersect on a side of the first lens surface,
• wherein a curvature of the second lens surface is smaller than a curvature of the first lens surface.

A LED head comprising:

• a lens array, the lens array including:
• a lens including a first lens surface and a second lens surface, wherein
• the first lens surface is formed to tilt at a predetermined tilt angle with respect to the second lens surface, and
• the first lens surface is formed to be eccentric by an eccentric distance in such a direction that the optical axis of the second lens surface and an optical axis of the first lens surface intersect on a side of the first lens surface.

A method for manufacturing a lens array by using a mold including a first mold configured to define a first lens surface, a second mold configured to define a second lens surface, and a gate through which a material is to be injected into a cavity formed between the first mold and the second mold, the method comprising:

• molding the material while the first lens surface and the second lens surface are displaced from each other in a direction of the gate;
• determining an eccentric distance such that a distance of displacement of an image due to a tilting of the first lens surface substantially matches a distance of displacement of an image due to an eccentricity of the first lens surface;
• and
• forming the first lens surface of the lens array and the second lens surface of the lens array using the first mold and the second mold such that the first lens surfaces is tilted at a predetermined tilt angle with respect to the second lens surface, and in which the first lens surface is eccentric by the eccentric distance in such a direction that an optical axis of the second lens surface and an optical axis of the first lens surface intersect on a side of the first lens surface.