Optical apparatus

An optical apparatus, comprising:

• a structured light generation unit outputting a structured light, wherein the structured light generation unit comprises at least one light source and an optical element group, wherein the at least one light source emits plural light beams, and the optical element group has a projection pattern, wherein after the plural light beams pass through the projection pattern, the structured light is generated;
• a conversion lens module arranged between the at least one light source and the optical element group, and expanding the plural light beams, wherein after the plural light beams pass through the conversion lens module, the plural light beams are projected on a projection surface, so that a structured light pattern is formed on the projection surface, wherein the conversion lens module comprises one or plural conversion lenses, and all of the conversion lenses have negative optical power;
• a collimating lens located beside the conversion lens module, wherein the expanded light beams are collimated by the collimating lens;
• and
• a casing accommodating the structured light generation unit, the conversion lens module and the collimating lens,
• wherein the conversion lens module comprises:
• a first conversion lens located near the light source for expanding the plural light beams;
• a second conversion lens arranged between the first conversion lens and the optical element group, wherein the plural light beams passing through the first conversion lens, once reaching the second conversion lens, are reflected by the second conversion lens;
• and
• a third conversion lens arranged between the first conversion lens and the optical element group, wherein the reflected light beams from the second conversion lens are further reflected by the third conversion lens and then directed to the collimating lens.