OPTICAL MODULE
The present invention relates to an optical module, especially an optical projector module, comprising: at least a light source, an optical lens construction and a diffractive optical element (DOE), wherein said optical lens construction comprises at least a first and a second lens group, said first and second lens group comprising each two lens surfaces, said lens surfaces having different optical properties, wherein said first lens group is positioned adjacent to said light source.
1 . An optical module, especially an optical projector module, comprising:
at least a light source, an optical lens construction and a diffractive optical element (DOE), wherein said optical lens construction comprises at least a first and a second lens group, said first and second lens group comprising each two lens surfaces, said lens surfaces having different optical properties, wherein said first lens group is positioned adjacent to said light source.
2 . An optical module according to claim 1 , wherein said first lens group comprises lens surface A and lens surface B, lens surface A being positioned adjacent to said light source, wherein said lens surface A is of the type convex and said lens surface B is of the type concave.
3 . An optical module according to claim 1 , wherein said second lens group comprises lens surface C and lens surface D, lens surface C being positioned adjacent to said first lens group, wherein said lens surface C is of the type concave and said lens surface D is of the type convex.
4 . An optical module according to claim 1 , wherein the range of index (n) of the polymer materials used for the lens surfaces is between 1.45 and 1.6.
5 . An optical module according to claim 1 , wherein the range of index (n) of the polymer materials used for the lens surfaces is between 1.6 and 1.8.
6 . An optical module according to claim 1 , wherein the axial length (track length) is at most 10 mm.
7 . An optical module according to claim 1 , wherein said optical lens construction further comprises at least a third group, said third lens group comprising each two lens surfaces, said lens surfaces having different optical properties.
8 . An optical module according to claim 7 , wherein said third lens group comprises lens surface E and lens surface F, lens surface F being positioned adjacent to said diffractive optical element (DOE).
9 . An optical module according to claim 8 , wherein said lens surface A is of the type convex, said lens surface B is of the type convex, said lens surface C is of the type concave, said lens surface D is of the type convex or of the type flat, said lens surface E is of the type convex or of the type flat, said lens surface F is of the type convex.
10 . An optical module according to claim 1 , wherein said at least a light source is chosen from the group of type of semiconductor laser diode, such as vertical-cavity surface-emitting laser (VCSEL), and coherent light sources, single or in plural (array).
11 . An optical module according to claim 1 , wherein each of said lens groups has been manufactured according replication technology.
12 . An optical module according to claim 7 , wherein the thickness of at least one lens element within the first, second and third lens group is in a range of from about 50 micron to about 400 micron, wherein the thickness is determined by the shortest path of the light rays through a lens group.
13 . An optical module according to claim 1 , wherein in one or more of each lens groups one or more additional layers are present, chosen from the group of integrated intermediate substrates, IR filters, UV filters, apertures and diaphragms, or combinations thereof.
14 . An optical module according to claim 1 , wherein the materials of each of said lens elements are chosen from the group of UV curable polymers, preferably epoxy, acrylic and nylon type polymers.
15 . An optical module according to claim 1 , wherein said optical properties are chosen from the group of shape, dimension, and material, or a combination thereof.
16 . An optical module according to claim 7 , wherein said optical module comprises three lens groups, said lens surfaces being made of high refractive index materials (1.6<n<1.8).
17 . An optical module according to claim 7 , wherein said optical module comprises three lens groups, said lens surfaces being made of normal refractive index materials (1.4<n<1.6).
18 . An optical module according to claim 1 , wherein said optical module comprises two lens groups, said lens surfaces being made of high refractive index (1.6<n<1.8).
19 . A method for projection, comprising:
directing an input beam of radiation to pass through an optical module according to any one more of the preceding claims, wherein the diffractive optical elements (DOE) is configured to generate a respective plurality of diffraction patterns at the respective beam angles, wherein each of the diffraction patterns comprises a set of spots corresponding to respective diffraction orders of a corresponding one of the output beams and projects a respective diffraction image comprising the spots onto a region in space.