Method for producing aspherical structure, and aspherical lens array molding tool and aspherical lens array produced by the same method

A method of producing an aspherical structure, comprising the steps of:

• forming a layer on a surface of a planar substrate so that said layer exhibits an etching rate distribution in a direction perpendicular to said surface of said planar substrate with respect to predetermined etching means;
• forming a mask having a predetermined opening shape on a surface of said layer;
• etching said layer through said mask for a predetermined time by said predetermined etching means to thereby form at least one concave portion;
• and
• filling said concave portion with a fluid substance and solidifying said fluid substance.

A method of producing an aspherical structure, comprising the steps of:

• forming a layer on a surface of a planar substrate so that said layer exhibits an etching rate distribution in a direction perpendicular to said surface of said planar substrate with respect to predetermined etching means;
• forming a mask having a predetermined opening shape on a surface of said layer;
• etching said layer through said mask for a predetermined time by said predetermined etching means to thereby form at least one concave portion;
• filling said concave portion with a fluid substance and solidifying said fluid substance;
• and
• removing the solidified substance from said concave portion.

A method of producing an aspherical lens molding tool, comprising the steps of:

• forming a homogeneous layer on a surface of a substrate, said layer being different in etching rate from said substrate;
• forming a mask on said layer, said mask having an opening shape;
• etching said layer and said substrate through said mask;
• removing said mask;
• and
• etching said layer and said substrate again to remove at least said layer and form a concave portion.

A method of producing an aspherical structure, comprising the steps of;

• providing a first layer having a first etching rate;
• providing a second layer on the first layer, the second layer having a second etching rate different from the first etching rate;
• etching the first layer to expose a part of the second layer;
• and
• further etching the first layer and the second layer to form an aspherical concave portion.