Optical apparatus
An optical apparatus includes a structured light generation unit, a conversion lens module, a collimating lens and a casing. The structured light generation unit outputs a structured light. The light beams from the structured light generation unit are expanded by the conversion lens module. The expanded light beams are collimated by the collimating lens. After the light beams pass through the conversion lens module and the collimating lens, the light beams are projected to a projection surface. Consequently, a structured light pattern is formed on the projection surface. All conversion lenses of the conversion lens module have negative optical power. Consequently, the area of the structured light pattern on the projection surface is wider. Moreover, the structured light generation unit and the conversion lens module can be accommodated within the casing having a smaller thickness.
1. 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.
2. The optical apparatus according to claim 1 , wherein the conversion lens module is a free-form lens module, and the conversion lens module has a non-linear optical axis, wherein when the plural light beams are incident on the optical element group, an included angle between the plural light beams and the optical element group is smaller than 5 degrees.
3. The optical apparatus according to claim 1 , wherein a numerical aperture of the first conversion lens is smaller than 0.8, and the plural light beams have a rectangular beam distribution or a ring-shaped beam distribution.
4. The optical apparatus according to claim 1 , wherein a first numerical aperture of the first conversion lens in a vertical direction is smaller than 0.6, and a second numerical aperture of the first conversion lens in a horizontal direction is smaller than 0.5, wherein the plural light beams have a rectangular beam distribution or a ring-shaped beam distribution.
5. The optical apparatus according to claim 1 , wherein the first conversion lens is asymmetric with respect to the optical axis of the conversion lens module, and a curvature of the first conversion lens in a vertical direction and a curvature of the first conversion lens in a horizontal direction are different, so that a beam distribution and a projecting direction of the light beams are controllable.
6. The optical apparatus according to claim 1 , wherein at least one of the first conversion lens and the collimating lens has an anti-reflection coating, and at least one of the second conversion lens and the third conversion lens has a high reflective coating, so that a beam distribution and a projecting direction of the plural light beams are controllable.
7. The optical apparatus according to claim 1 , wherein the collimating lens is asymmetric with respect to the optical axis of the conversion lens module, and a curvature of the collimating lens in a vertical direction and a curvature of the collimating lens in a horizontal direction are different, so that a beam distribution and a projecting direction of the light beams are controllable.
8. The optical apparatus according to claim 1 , further comprising a spatial filter, wherein the spatial filter is arranged between the collimating lens and the optical element group or arranged between the at least one light source and the conversion lens module, wherein the spatial filter filters noise of the plural light beams.
9. The optical apparatus according to claim 1 , wherein the optical element group comprises a diffractive optical element, a refractive optical element and/or a refractive array optical element.
10. The optical apparatus according to claim 1 , wherein a thickness of the casing is smaller than 6 mm.
11. 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;
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 a thickness of the casing is smaller than 4 mm,
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.