Autofocus system

This patent application claims benefit of a provisional patent application 62/096,854. The disclosure made in the provisional patent application 62/096,854 is hereby incorporated by reference.

This invention relates generally to an autofocus system for a camera module. More particularly, the present invention relates to an autofocus system allowing three degrees of freedoms of translational adjustments and two degrees of freedoms of rotational adjustments.

Autofocus is now a standard function in miniature cameras. There is a constant need to improve performance of autofocus. It is advantageous to extend the autofocus technology to include more degrees of freedoms of translational and rotational adjustments.

This invention discloses an autofocus system that allows three degrees of freedoms of translational adjustments and two degrees of freedoms of rotational adjustments. The autofocus system includes a lens assembly, an upper actuator, and a lower actuator. The upper and the lower actuators have stationary elements and movable elements. The lens assembly is attached to the movable elements of the upper and the lower actuators. In addition to improving the autofocus function, the capabilities of the translational adjustments and the rotational adjustments may balance the shock and vibration induced by user's hands. Thus, the steady-shot function of the camera module is also improved.

FIG. 1 is a schematic perspective view of an autofocus system in examples of the present disclosure.

FIG. 2 is a bottom view of the autofocus system of FIG. 1 .

FIG. 3 is a cross-sectioned view of another autofocus system in examples of the present disclosure.

FIG. 4 is a schematic perspective view of an actuator in examples of the present disclosure.

FIG. 5 is an exploded plot of the actuator of FIG. 4 .

FIG. 6 is a top view of the actuator of FIG. 4 .

FIG. 7 is an exploded plot of another actuator in examples of the present disclosure.

FIG. 1 is a schematic perspective view of an autofocus system 100 in examples of the present disclosure. FIG. 2 is a bottom view of autofocus system 100 of FIG. 1 . As shown in FIG. 1 and FIG. 2 , autofocus system 100 includes a lens assembly 120 , an upper actuator 1100 and a lower actuator 2100 . Upper actuator 1100 includes one or more upper stationary elements 1500 , a first upper translation element 1200 to translate along X direction, a second upper translation element 1300 to translate along Y direction, and a third upper translation element 1400 to translate along Z direction. Lower actuator 2100 includes one or more lower stationary elements 2500 , a first lower translation element 2200 to translate along X direction, a second lower translation element 2300 to translate along Y direction, and a third lower translation element 2400 to translate along Z direction. Lens assembly 120 may attach to first upper translation element 1200 and first lower translation element 2200 .

In examples of the present disclosure, the translations of translation elements 1200 , 1300 , 1400 , 2200 , 2300 , and 2400 may be driven by electrostatic comb drives.

In examples of the present disclosure, lens assembly 120 moves along positive X direction when first upper translation element 1200 and first lower translation element 2200 translate a positive displacement along X axis. Lens assembly 120 , first upper translation element 1200 and first lower translation element 2200 move along positive Y direction when second upper translation element 1300 and second lower translation element 2300 translate a positive displacement along Y axis. Lens assembly 120 , first upper translation element 1200 , first lower translation element 2200 , second upper translation element 1300 and second lower translation element 2300 move along positive Z direction when third upper translation element 1400 and third lower translation element 2400 translate a positive displacement along Z axis.

In examples of the present disclosure, lens assembly 120 rotates about an axis parallel to Y axis when first upper translation element 1200 translates a positive displacement along X axis and first lower translation element 2200 translates a negative displacement along X axis. Lens assembly 120 , first upper translation element 1200 and first lower translation element 2200 rotates about an axis parallel to X axis when second upper translation element 1300 translates a negative displacement along Y axis and second lower translation element 2300 translates a positive displacement along Y axis.

In one example, lens assembly 120 includes a single lens. In another example, lens assembly 120 includes a barrel and one or more lenses.

FIG. 3 is a cross-sectioned view of another autofocus system 300 in examples of the present disclosure. Autofocus system 300 includes a lens assembly 320 , an upper actuator 3100 , a lower actuator 4100 , and a substrate 340 . Substrate 340 may be located between upper actuator 3100 and lower actuator 4100 . Substrate 340 may have an annular opening to receive lens assembly 320 . A first set of solder balls 360 may connect substrate 340 and upper actuator 3100 . A second set of solder balls 380 may connect substrate 340 and lower actuator 4100 .

FIG. 4 is a schematic perspective view of an actuator 1100 in examples of the present disclosure. Actuator 1100 includes one or more stationary elements 1500 , a first translation element 1200 to translate along X direction, a second translation element 1300 to translate along Y direction, and a third translation element 1400 to translate along Z direction.

In examples of the present disclosure, first translation element 1200 , second translation element 1300 , and third translation element 1400 are in cylindrical shapes and have the same central axis (Z axis). In one example, the radius of first translation element 1200 is smaller than the radius of second translation element 1300 and the radius of second translation element 1300 is smaller than the radius of third translation element 1400 . In another example, the radius of first translation element 1200 is larger than the radius of second translation element 1300 and the radius of third translation element 1400 is larger than the radius of first translation element 1200 .

FIG. 5 is an exploded plot of actuator 1100 of FIG. 4 . Actuator 1100 may include a top layer 1111 and a bottom layer 1191 . In one example, top layer 1111 is attached to bottom layer 1191 . In another example, top layer 1111 is attached to a middle layer (for example, 8140 of FIG. 7 ) and the middle layer is attached to bottom layer 1191 . In examples of the present disclosure, top layer 1111 and bottom layer 1191 are made of silicon and middle layer is made of silicon oxide. FIG. 7 is a variation of FIG. 5 . Top layer 1111 is attached to a middle layer 8140 and the middle layer is attached to bottom layer 1191 .

Top layer 1111 may include ground electrode member 1122 , ground electrode member 1124 , ground electrode member 1126 , X-driving electrode member 1132 , X-driving electrode member 1134 , Y-driving electrode member 1142 , and Y-driving electrode member 1144 . Ground electrode members 1122 , 1124 , and 1126 connect to ground. X-driving electrode members 1132 and 1134 connect to driving voltage potentials. Y-driving electrode members 1142 and 1144 connect to driving voltage potentials.

Bottom layer 1191 may include Z-driving electrodes 1542 , 1544 , 1546 , 1548 , 1550 , 1552 , 1554 , and 1556 , support ring 1322 , and support ring 1422 .

First translation element 1200 may be in top layer 1111 . Second translation element 1300 may include arc member 1312 , arc member 1314 , arc member 1316 , and arc member 1318 in top layer 1111 and support ring 1322 in bottom layer 1911 . Third translation element 1400 may include arc member 1412 , arc member 1414 , arc member 1416 , and arc member 1418 in top layer 1111 and support ring 1422 in bottom layer 1911 .

In examples of the present disclosure, moving electrodes 1442 , 1444 , 1446 , 1448 , 1450 , 1452 , 1454 , and 1456 are engaged with Z-driving electrodes 1542 , 1544 , 1546 , 1548 , 1550 , 1552 , 1554 , and 1556 to form eight out-of-plane comb drives.

FIG. 6 is a top view of actuator 1100 of FIG. 4 . Actuator 1100 further includes X-translational springs 1282 , 1284 , 1286 , and 1288 , Y-translational springs 1392 , 1394 , 1396 , and 1398 , and one or more Z-translational springs 1591 . X-translational springs 1282 , 1284 , 1286 , and 1288 connect first translation element 1200 and second translation element 1300 . Y-translational springs 1392 , 1394 , 1396 , and 1398 connect second translation element 1300 and third translation element 1400 .

Moving electrodes 1272 and 1274 extending from first translation element 1200 are engaged with X-driving electrodes 1372 and 1374 extending from second translation element 1300 to form two in-plane comb drives. Moving electrodes 1362 and 1364 extending from second translation element 1300 are engaged with Y-driving electrodes 1462 and 1464 extending from third translation element 1400 to form two in-plane comb drives.

Those of ordinary skill in the art may recognize that modifications of the embodiments disclosed herein are possible. For example, the numbers of springs may vary; the springs may be linear springs, serpentine springs, or other kinds of springs; the numbers of comb drives may vary; and the numbers and the shapes of the comb teeth of the comb drives may vary. Other modifications may occur to those of ordinary skill in this art, and all such modifications are deemed to fall within the purview of the present invention, as defined by the claims.