# US 12,007,679 B1 · Macro-to-micro two-stage camera lens focusing device based on direct-drive air floatation platform

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- Number: US 12,007,679 B1
- Document ID: US12007679B1
- Status: Granted
- Kind: B1
- Application number: 18/416,925
- Filed: 2024-01-19
- Granted: 2024-06-11
- Earliest claimed: 2023-04-21
- Assignees: Guangdong University of Technology
- Applicants: Guangdong University of Technology
- Inventors: Ping Ma; Heng Ding; Hongda Zhao; Xinghua Wang
- Web page: https://patentgrep.com/patent/US12007679B1

## CPC

- G03B 3/10: Power-operated focusing
- G03B 13/36: Autofocus systems
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)

## Abstract

A macro-to-micro two-stage camera lens focusing device based on a direct-drive air floatation platform includes: a two-stage motion device with macro-motion and micro-motion focusing systems. The focusing device includes: a z-direction macro-motion system, a z-direction micro-motion focusing system, and a y-direction micro-motion focusing system. The macro-motion system includes flat-plate linear motors, a tubular linear motor, a tubular elastic balancing device, and an aerostatic air flotation platform; and the micro-motion focusing system includes a micro-motion platform base, piezoceramic actuators, micro-motion flexure hinges, a micro-motion platform, and an industrial camera lens. The focusing device realizes macro-to-micro two-stage focusing, captures a target through rapid motion of the aerostatic air flotation platform and the linear motors to perform coarse focusing, completes the micro-motion focusing by the piezoceramic actuators and the flexure hinges, realizes large-scale, high-speed, high-acceleration, high-precision, and high-stability focusing of two-stage focusing technology, and improves precision and efficiency of industrial measurement.

## Claims

### Claim 1

A macro-to-micro two-stage camera lens focusing device based on a direct-drive air floatation platform, configured to be mounted on a y axis (2) of an aerostatic air flotation platform and comprising:
a base (10), configured to be disposed on the y axis (2) of the aerostatic air flotation platform;
a z-direction macro-motion system, disposed on the base (10), wherein the z-direction macro-motion system is configured to realize macro-motion focusing of an industrial camera lens (15) along a z direction;
a micro-motion focusing system, comprising: a z-direction micro-motion focusing system and a y-direction micro-motion focusing system; wherein the z-direction micro-motion focusing system is disposed above the z-direction macro-motion system, and the y-direction micro-motion focusing system is disposed above the z-direction micro-motion focusing system; each of the z-direction micro-motion focusing system and the y-direction micro-motion focusing system adopts a structure combining rigid arms and flexible arms; and the z-direction micro-motion focusing system and the y-direction micro-motion focusing system are configured to realize micro-motion focusing along the z direction and a y direction, respectively;
wherein the z-direction micro-motion focusing system comprises:
a micro-motion platform (13), slidably connected to the base (10);
a micro-motion platform base (14), fixedly connected to the micro-motion platform (13);
a z-direction micro-motion flexure hinge (16), fixedly disposed on the micro-motion platform base (14);
a z-direction piezoceramic actuator (17), fixedly disposed in the micro-motion platform base (14) and the z-direction micro-motion flexure hinge (16); wherein a top portion of the z-direction piezoceramic actuator (17) is configured to push the z-direction micro-motion flexure hinge (16) to perform nanoscale motion through a piezoelectric effect, thereby completing the micro-motion focusing along the z direction; and
the industrial camera lens (15), disposed on the z-direction micro-motion flexure hinge (16);
wherein the y-direction micro-motion focusing system comprises:
a y-direction micro-motion flexure hinge (20), fixedly disposed on the micro-motion platform (13) and fixedly connected to the micro-motion platform base (14);
a y-direction piezoceramic mounting base (24), fixedly disposed on the micro-motion platform (13);
a y-direction piezoceramic actuator (19), fixedly disposed in the y-direction piezoceramic mounting base (24); wherein the y-direction piezoceramic actuator (19) is configured to make the micro-motion platform base (14) generate a micro displacement along the y direction by pushing a side of the micro-motion platform base (14), thereby causing the industrial camera lens (15) disposed on the micro-motion platform base (14) to produce the micro-motion focusing along the y direction; and
two y-direction micro-motion guideways (23), fixedly disposed on the micro-motion platform (13), wherein the micro-motion platform base (14) is fixedly disposed on the two y-direction micro-motion guideways (23) to complete an installation of the micro-motion platform (13) that is disposed along the z direction, and the micro-motion platform (13) is configured to perform micro motion along the y direction through the two y-direction micro-motion guideways (23);
wherein the micro-motion platform base (14) comprises: a body (141);
wherein a bottom of the body (141) defines two first rabbets (142), and the two first rabbets (142) are disposed corresponding to the two y-direction micro-motion guideways (23);
wherein a top portion of the body (141) defines a cylindrical positioning groove (143), and the z-direction piezoceramic actuator (17) is disposed in the cylindrical positioning groove (143);
wherein the top portion of the body (141) further defines two second rabbets (144), the two second rabbets (144) are symmetrically disposed on two sides of the cylindrical positioning groove (143), and the two second rabbets (144) are designed according to a shape of the z-direction micro-motion flexure hinge (16); and
wherein a middle portion of the body (141) defines a third rabbet (145), and a z-direction micro-motion guideway (25) is fixedly disposed in the third rabbet (145).

### Claim 2 (depends on 1)

The focusing device as claimed in claim 1, wherein the z-direction micro-motion flexure hinge (16) comprises:
a first rigid arm (161);
two second rigid arms (162), symmetrically disposed on two sides of the first rigid arm (161);
four bridge-typed flexure hinges (163), wherein two of the four bridge-typed flexure hinges (163) are fixedly connected between a side wall of the first rigid arm (161) and one of the two second rigid arms (162), and remaining two of the four bridge-typed flexure hinges (163) are fixedly connected between another side wall of the first rigid arm (161) and the other second rigid arm (162); and
wherein a bottom of the first rigid arm (161) is fixedly connected to the z-direction micro-motion guideway (25), the z-direction micro-motion guideway (25) is fixedly disposed in the third rabbet (145), the first rigid arm (161) defines a groove thereon disposed corresponding to the cylindrical positioning groove (143), the z-direction piezoceramic actuator (17) is embedded in a cavity defined by the groove and the cylindrical positioning groove (143); and the two second rigid arms (162) are fixedly connected to the two second rabbets (144), respectively.

### Claim 3 (depends on 1)

The focusing device as claimed in claim 1, wherein the y-direction micro-motion flexure hinge (20) comprises:
an inner rigid arm (201), fixedly connected to the micro-motion platform (13);
an outer rigid arm (202), wherein a side of the outer rigid arm (202) is fixedly connected to the side of the micro-motion platform base (14); and
four s-shaped flexure hinges (203), wherein two of the four s-shaped flexure hinges (203) are fixedly connected between a side wall of the inner rigid arm (201) and an inner side wall of the outer rigid arm (202), and remaining two of the four s-shaped flexure hinges (203) are fixedly connected between another side wall of the inner rigid arm (201) and the inner side wall of the outer rigid arm (202); and wherein the four s-shaped flexure hinges (203) are disposed symmetrically in pairs.

### Claim 4 (depends on 1)

The focusing device as claimed in claim 1, wherein the z-direction macro-motion system comprises: a supporting guideway assembly, a tubular linear motor (9), and a tubular elastic balancing device (12), which are fixedly connected to the base (10);
wherein the micro-motion platform (13) is slidably connected to the supporting guideway assembly, and the supporting guideway assembly is staggered with the tubular linear motor (9) and the tubular elastic balancing device (12); and
wherein the supporting guideway assembly comprises: a guideway I (11A) and a guideway II (11B), which are fixedly connected to the micro-motion platform (13); the tubular linear motor (9) is disposed between the guideway I (11A) and the guideway II (11B); and the tubular elastic balancing device (12) is disposed close to the guideway I (11A).

### Claim 5 (depends on 4)

The focusing device as claimed in claim 4, wherein an elastic anti-collision limit block group is fixedly connected to the guideway I (11A) and the guideway II (11B);
wherein the elastic anti-collision limit block group comprises: an elastic anti-collision limit block I (18A), an elastic anti-collision limit block II (18B), an elastic anti-collision limit block III (18C), and an elastic anti-collision limit block IV (18D), which are fixedly connected to the micro-motion platform (13); and
wherein the elastic anti-collision limit block I (18A) and the elastic anti-collision limit block IV (18D) are fixedly connected to two ends of the guideway I (11A), respectively; and the elastic anti-collision limit block II (18B) and the elastic anti-collision limit block III (18C) are fixedly connected to two ends of the guideway II (11B), respectively.

### Claim 6 (depends on 1)

The focusing device as claimed in claim 1, wherein a mounting base (22) is fixedly connected to the z-direction micro-motion flexure hinge (16), and the industrial camera lens (15) is disposed on the mounting base (22).