Optical illumination device

1. An optical illumination device comprising:

a laser light source;

a plurality of microlens arrays through which light emitted from the laser light source passes;

a moving mechanism that moves the plurality of microlens arrays without changing an optical length from the laser light source; and

a Fourier lens through which light passing through the plurality of microlens arrays passes,

wherein the plurality of microlens arrays and the Fourier lens constitute a Koehler illumination system,

a microlens array is configured to rotate around an axis which is perpendicular to the microlens array,

the moving mechanism causes the microlens array to rotate around the axis, and

a plurality of lenses constituting the microlens array are arranged in a spiral shape.

2. The optical illumination device according to claim 1 ,

wherein the plurality of microlens arrays include a first microlens array and a second microlens array which are disposed to face each other, and

wherein a relative position between the first microlens array and the second microlens array is fixed.

3. The optical illumination device according to claim 2 , the optical illumination device further comprising a connection portion that connects the first microlens array and the second microlens array to each other,

wherein the first microlens array and the second microlens array are able to rotate integrally.

4. The optical illumination device according to claim 3 ,

wherein the first microlens array and the second microlens array have a disc shape, and

wherein the first microlens array and the second microlens array are able to rotate integrally around the same axis.

5. The optical illumination device according to claim 1 ,

wherein the microlens array is disposed to be perpendicular to a direction of light which is emitted from the laser light source.

6. The optical illumination device according to claim 1 ,

wherein the microlens array has a disc shape, and

wherein the plurality of lenses are displaced from each other in position in a radial direction of the microlens array and are displaced from each other in position in a circumferential direction of the microlens array.

7. The optical illumination device according to claim 6 ,

wherein an amount of displacement in the radial direction and an amount of displacement in the circumferential direction of neighboring lenses out of the plurality of lenses are fixed.

8. The optical illumination device according to claim 1 ,

wherein the plurality of microlens arrays include a first microlens array and a second microlens array which are disposed to face each other,

wherein the first microlens array includes a plurality of first lenses that are arranged in a spiral shape, and

wherein the second microlens array includes a plurality of second lenses that are arranged in a spiral shape.

9. The optical illumination device according to claim 8 ,

wherein the first microlens array and the second microlens array have a disc shape,

wherein the plurality of first lenses are displaced from each other in position in a radial direction of the first microlens array and are displaced from each other in position in a circumferential direction of the first microlens array, and

wherein the plurality of second lenses are displaced from each other in position in a radial direction of the second microlens array and are displaced from each other in position in a circumferential direction of the second microlens array.

10. The optical illumination device according to claim 8 ,

wherein arrangement of the plurality of second lenses of the second microlens array when seen in a thickness direction thereof corresponds to arrangement of the plurality of first lenses in a one-to-one manner.

11. The optical illumination device according to claim 10 ,

wherein a relative position between one lens out of the plurality of first lenses and one lens corresponding thereto out of the plurality of second lenses is fixed.

12. The optical illumination device according to claim 8 ,

wherein the plurality of first lenses split the light emitted from the laser light source into a plurality of light beams, and

wherein the plurality of second lenses condense the plurality of light beams output from the plurality of first lenses.

13. An optical illumination device comprising:

a laser light source;

one or more microlens arrays through which light emitted from the laser light source passes;

a moving mechanism that moves the microlens array without changing an optical length from the laser light source; and

a Fourier lens through which light passing through the microlens array passes,

wherein the microlens array rotates around an axis which is perpendicular to the microlens array,

wherein the moving mechanism causes the microlens array to rotate around the axis,

wherein the plurality of microlens arrays include a first microlens array and a second microlens array which are disposed to face each other,

wherein the first microlens array includes a plurality of first lenses that are arranged in a spiral shape,

wherein the second microlens array includes a plurality of second lenses that are arranged in a spiral shape,

wherein the first microlens array and the second microlens array have a disc shape,

wherein the plurality of first lenses are displaced from each other in position in a radial direction of the first microlens array and are displaced from each other in position in a circumferential direction of the first microlens array,

wherein the plurality of second lenses are displaced from each other in position in a radial direction of the second microlens array and are displaced from each other in position in a circumferential direction of the second microlens array, and

wherein an amount of displacement in the radial direction and an amount of displacement in the circumferential direction of neighboring lenses out of the plurality of first lenses and an amount of displacement in the radial direction and an amount of displacement in the circumferential direction of neighboring lenses out of the plurality of second lenses are the same.

14. An optical illumination device comprising:

a laser light source;

a first microlens array and second microlens array through which light emitted from the laser light source passes, the first microlens array and the second microlens array being disposed to face each other;

a moving mechanism that moves the first and second microlens arrays without changing an optical length from the laser light source; and

a Fourier lens through which light passing through the first and second microlens arrays passes,

wherein the moving mechanism causes the first and second microlens arrays to rotate around an axis perpendicular to the first and second microlens arrays,

each of the first and second microlens arrays comprises a plurality of lenses that are arranged around the axis, and an outer diameter of each of the plurality of lenses is from 0.3 mm to 0.8 mm, and

the light emitted from the laser light source passes the plurality of lenses which are arranged around the axis.