Projection aligner

A projection aligner for transferring an image of a pattern on a mask to an object to be exposed, said projection aligner comprising:

• a lens unit having an optical axis parallel to the mask;
• a reflector provided to one side of said lens unit to reflect back light passed therethrough;
• a light source that emits a light beam toward the object through the mask;
• and
• a deflector being inserted in an optical path of the light beam at the other side of said lens unit, said deflector being movable along the optical axis of said lens unit, said deflector having first and second mirrors inclined against the optical axis of said lens unit in opposite directions to each other, said first mirror arranged to deflect the light beam coming from the mask toward said reflector through said lens unit, said second mirror arranged to deflect the light beam reflected by said reflector and passed through said lens unit toward the object.