Lens unit, optical head and image formation apparatus

A lens unit comprising:

• a lens array that includes lens elements each provided with an optical axis and extends in a first direction;
• a support member that supports the lens array;
• and
• an adhesive that bonds the lens array and the support member, wherein
• the support member includes a first adhesive holding portion with a first depth in a direction of the optical axis and a second adhesive holding portion shallower than the first adhesive holding portion,
• the first adhesive holding portion and the second adhesive holding portion are arranged in the first direction,
• the adhesive is provided at the first adhesive holding portion and the second adhesive holding portion,
• the first adhesive holding portion and the second adhesive holding portion include openings at a surface of the support member, and
• at least one of side surfaces of the first adhesive holding portion in the first direction is inclined so that a width of the first adhesive holding portion in the first direction increases toward the opening of the first adhesive holding portion in the direction of the optical axis.

A lens unit comprising:

• a lens array that includes lens elements each provided with an optical axis and extends in a first direction;
• a support member that includes a first surface and a second surface opposite to the first surface in a direction of the optical axis and that supports the lens array;
• and
• an adhesive that bonds the lens array and the support member, wherein
• the support member includes:
• a first adhesive holding portion including a first opening end and a first bottom surface with a first depth from the first opening end in the direction of the optical axis;
• and a second adhesive holding portion including a second opening end and a second bottom surface with a second depth from the second opening end in the direction of the optical axis, wherein the second depth of the second adhesive holding portion is less than the first depth of the first adhesive holding portion,
• the first adhesive holding portion and the second adhesive holding portion are arranged in the first direction,
• the adhesive is provided in the first adhesive holding portion and the second adhesive holding portion,
• the first opening end and the second opening end are provided at the first surface of the support member, and
• a material of the adhesive in the first adhesive holding portion and a material of the adhesive in the second adhesive holding portion are the same and are ultraviolet curable adhesive.