Input device, non-contact operation unit, and image forming apparatus

A non-contact operation unit comprising:

• an attachment attachable to an input device having a display having a display surface on which an operation screen is displayed;
• a light emitter to emit light in a first direction to form a detection plane above the display surface to detect an object;
• and
• a light receiver to receive reflection light, emitted from the light emitter and reflected from the object on the detection plane, to detect a position of the object on the detection plane,
• wherein the detection plane is inclined with respect to the display surface, and
• the detection plane has:
• a first distance between:
• a first end of the display surface in the first direction;
• and
• a first position on the detection plane, the first position at a position where a perpendicular line perpendicular to the display surface and extending from the first end intersects the detection plane at the first position;
• and
• a second distance between:
• a second end, opposite to the first end, of the display surface in the first direction;
• and
• a second position on the detection plane, the second position at a position where a perpendicular line perpendicular to the display surface and extending from the second end intersects the detection plane at the second position, and
• the first distance is shorter than the second distance.