Automatic focus imaging system using out-of-plane translation of an MEMS reflective surface
View Patent ↗The present invention provides an automatic focus imaging system comprising a lens unit, an image sensor, and a Micro-Electro-Mechanical System (MEMS) unit fabricated by microfabrication technology to improve the portability and focusing speed of the automatic focus imaging system. The MEMS unit for automatic focusing comprises a substrate having a control circuitry, at least one reflective surface movably connected to the substrate, and at least one actuation unit comprising a micro-actuator having a large in-plane translation and at least one micro-converter configured to convert the large in-plane translation of the micro-actuator to the large out-of-plane translation of the reflective surface. The MEMS unit changes a distance between lens unit and the image sensor by controlling the out-of-plane translation of the reflective surface in order to form an in-focus image on the image sensor.
1. An automatic focus imaging system comprising:
a lens unit;
an image sensor; and
a Micro-Electro Mechanical System (MEMS) unit comprising a substrate having a control circuitry, a reflective surface movably connected to the substrate, and at least one actuation unit comprising:
a micro-actuator disposed on the substrate and driven by the control circuitry to have in-plane translation; and
at least one micro-converter having a primary end, wherein the primary end of at least one of the at least one micro-converter is rotatably connected to the micro-actuator and the micro-actuator with the in-plane translation exerts a force on the primary end of the at least one of the at least one micro-converter, wherein the at least one micro-converter delivers the force to the reflective surface so that the reflective surface has a motion comprising out-of-plane translation;
wherein the MEMS unit changes a distance between the lens unit and the image sensor by controlling the out-of-plane translation of the reflective surface in order to form an in-focus image on the image sensor, wherein the MEMS unit is fabricated by microfabrication technology to improve portability and focusing speed of the automatic focus imaging system.
2. The automatic focus imaging system of claim 1 , wherein at least one of the at least one micro-converter comprises a first beam and a second beam, wherein a first end of the first beam is the primary end and a second end of the first beam is rotatably connected to the reflective surface, wherein a first end of the second beam is rotatably connected to the reflective surface and a second end of the second beam is rotatably connected to the substrate.
3. The automatic focus imaging system of claim 1 , wherein at least one of the at least one micro-converter comprises a first beam and a second beam, wherein a first end of the first beam is the primary end and a second end of the first beam is rotatably connected to a first end of the second beam, wherein a second end of the second beam is rotatably connected to the substrate, wherein the reflective surface is pushed by a pivot point connecting the second end of the first beam and the first end of the second beam in order to have the motion.
4. The automatic focus imaging system of claim 1 , wherein at least one of the at least one micro-converter comprises at least one beam, wherein a first end of the beam is the primary end and a second end of the beam is rotatably connected to the reflective surface.
5. The automatic focus imaging system of claim 1 , wherein at last one of the at least one micro-converter is rotatably connected to the reflective surface.
6. The automatic focus imaging system of claim 1 , wherein at least one of the at least one micro-converter is rotatably connected to the substrate.
7. The automatic focus imaging system of claim 1 , wherein the reflective surface is pushed by at least one of the at least one micro-converter in order to have the motion.
8. The automatic focus imaging system of claim 1 , wherein the primary ends of a plurality of the at least on micro-converters are rotatably connected to the micro-actuator and the micro-actuator with the in-plane translation exerts the forces on the primary ends of the plurality of the at least one micro-converters, wherein the at least one micro-converter delivers the forces to the reflective surface so that the reflective surface has a motion comprising out-of-plane translation.
9. The automatic focus imaging system of claim 1 , wherein the primary end of at least another one of the at least one micro-converter slides on the substrate.
10. The automatic focus imaging system of claim 1 , wherein the primary end of at least another one of the at least one micro-converter rolls on the substrate.
11. The automatic focus imaging system of claim 1 , wherein the primary end of at least another one of the at least one micro-converter is rotatably connected to the substrate.
12. The automatic focus imaging system of claim 1 , wherein the MEMS unit further comprises at least one flexible member connecting the reflective surface and the substrate and providing restoring force to the reflective surface.
13. The automatic focus imaging system of claim 1 , further comprising a beam splitter positioned between the lens unit and the MEMS unit.
14. The automatic focus imaging system of claim 1 , wherein the reflective surface is obliquely positioned between the lens unit and the image sensor such that the reflective surface reflects light received from the lens unit to the image sensor.
15. The automatic focus imaging system of claim 1 , further comprising a focus status determination unit in communication with the control circuit to provide focus status to the control circuitry in order to automatically control the out-of-plane translation of the reflective surface.
16. The automatic focus imaging system of claim 1 , wherein the micro-actuator is a comb-drive.
17. The automatic focus imaging system of claim 1 , wherein the MEMS unit comprises a plurality of the at least one actuation units.
18. The automatic focus imaging system of claim 17 , wherein each of the micro-actuators in the plurality of the at least one actuation units is driven independently by the control circuitry.
19. The automatic focus imaging system of claim 18 , wherein the motion of the reflective surface further comprises rotation, wherein the micro-actuators driven independently control the rotation of the reflective surface.
20. An automatic focus imaging system comprising:
a lens unit;
an image sensor; and
a Micro-Electro Mechanical System (MEMS) unit comprising a substrate having a control circuitry, a plurality of reflective surfaces movably connected to the substrate, and at least one actuation unit comprising:
a micro-actuator disposed on the substrate and driven by the control circuitry to have in-plane translation; and
at least one micro-converter having a primary end, wherein the primary end of at least one of the at least one micro-converter is rotatably connected to the micro-actuator and each of the reflective surfaces is coupled to at least one of the at least one micro-converter, wherein the micro-actuator with the in-plane translation exerts a force on the primary end of the at least one of the at least one micro-converter, wherein the at least one micro-converter delivers the force to the plurality of reflective surfaces so that each of the plurality of reflective surfaces has a motion comprising out-of-plane translation;
wherein the MEMS unit changes a distance between lens unit and the image sensor by controlling the out-of-plane translation of each of the plurality of reflective surfaces in order to form an in-focus image on the image sensor, wherein the MEMS unit is fabricated by microfabrication technology to improve portability and focusing speed of the automatic focus imaging system.