F-THETA LENS FOR LASER SCANNING UNIT HAVING RIB PORTION PROTECTING MIRROR SURFACE PORTION AND LASER SCANNING UNIT HAVING THE SAME

摘要

PURPOSE: An f-theta lens for a laser scanning unit and a laser scanning unit having the same are provided to protect a mirror surface portion by using a rib portion which is higher that a peak point of the mirror surface portion. CONSTITUTION: An f-theta lens(210) for a laser scanning unit includes a mirror surface portion(211) and a rib portion(212). The mirror surface portion focuses an incident light on a scanning surface. The rib portion is formed on both ends of the mirror surface portion to protect the mirror surface portion. A height of the rib is varying with respect to a peak point of the mirror surface portion.