TW202419909A - Guided autofocus assembly - Google Patents

Abstract

A buckler wire actuator assembly is provided herein. The buckler wire actuator assembly includes at least one buckler frame mounted onto a base of the buckler wire actuator assembly and including at least one isolated electrical conductor. The buckler wire actuator assembly also includes a first SMA wire in electrical connection to one of the at least one isolated electrical conductor a second SMA wire opposite the first SMA wire. The first and second SMA wires are arranged in series to enable both the first and second SMA wires to receive equal current from a current input.

Description

Guided auto focus assembly

Embodiments of the present invention relate to the field of shape memory alloy systems. More particularly, embodiments of the present invention relate to the field of shape memory alloy actuators and related methods.

Shape Memory Alloy ("SMA") systems have a moving assembly or structure that can be used as an autofocus actuator in conjunction with a camera lens element, for example. These systems can be enclosed by a structure such as a shield. The moving assembly is supported for movement on a support assembly. A flexible element formed of a metal such as phosphor bronze or stainless steel has a moving plate and a flexure. The flexure extends between the moving plate and the fixed support assembly and acts as a spring to enable the moving assembly to move relative to the fixed support assembly. The moving assembly and the support assembly are coupled by four Shape Memory Alloy (SMA) wires extending between the assemblies. Each of the SMA wires has one end attached to the support assembly, and an opposite end attached to the moving assembly. The suspension is actuated by applying an electrical drive signal to the SMA wires. However, these types of systems suffer from system complexity, which results in bulky systems requiring a large footprint and a large height clearance. Additionally, current systems are unable to provide a high Z-stroke range in a compact, low profile footprint.

A snap wire actuator assembly is provided herein. The snap wire actuator assembly includes at least one snap frame mounted on a base of the snap wire actuator assembly and includes at least one isolated electrical conductor. The snap wire actuator assembly also includes a first SMA wire electrically connected to one of the at least one isolated electrical conductor and a second SMA wire opposite the first SMA wire. The first and second SMA wires are configured in series so that both the first and second SMA wires can receive equal current from a current input.

Other features and advantages of embodiments of the present invention will become apparent from the accompanying drawings and the following detailed description.

Cross-reference to related applications

This application claims the rights and priority of U.S. Patent Application No. 17/871,780 filed on July 22, 2022, the entire text of which is incorporated herein by reference.

An embodiment of a guided autofocus assembly is described herein that includes a compact footprint and achieves a high actuation height, such as movement in the positive z-axis direction (z-direction), referred to herein as z-stroke. FIG. 1 illustrates a guided autofocus assembly 100 according to an embodiment of the present invention. The assembly 100 includes an optical axis 29 configured to be aligned with an image sensor. The assembly 100 also includes a housing 40 and a hall housing wall 42. The assembly 100 includes a magnetic element 37 configured to be attached to a flexible printed circuit board ("FPC") 38. The flexible printed circuit board is configured to be attached to the hall housing wall 42. As seen in FIG. 2 , the magnetic element 37 is positioned on a first side of the assembly 100 relative to the Hall sensor 36 such that the Hall sensor 36 is configured to indicate the position of a lens element along the optical axis 29 .

FIG2 shows an exploded view of the guided autofocus assembly of FIG1 according to an embodiment of the present invention. The assembly 100 includes a cover 9, a spring element 20, a lens holder 300, a housing element 40, a first buckle frame 50A, a second buckle frame 50B, an SMA wire 80, a sliding base 60 and an assembly base 70. The lens holder 300 can be received in the housing element 40.

The cover 9 is configured to fix the spring element 20 to the lens holder 300. The spring element 20 is configured to apply a force to the lens holder 300 in a direction opposite to the z-stroke direction, and according to some embodiments, the force is in a direction parallel to the optical axis 29. According to various embodiments, when the tension in the SMA wires 80A and 80B is reduced due to the deactivation of the SMA wires, the spring element 20 is configured to move the lens holder 300 in a direction opposite to the z-stroke direction. According to some embodiments, the spring element 20 is made of stainless steel.

The housing 40 includes a central wall 44, a first adjacent wall 46, a second adjacent wall 48, and an opening surface 43 opposite to the central wall 44. The housing 40 also defines a receiving space 41. The receiving space 41 is configured to receive the lens holder 300. The housing 40 also includes a Hall housing wall 42. The Hall housing wall 42 is configured to fix one or more ball bearings, a Hall magnet 32, and a Hall sensor 36. The Hall magnet 32 is fixed to the lens holder 300. According to some embodiments, the Hall sensor 36 is fixed in a hole 42B in the Hall housing wall 42.

Although ball bearings are shown herein, the bearings may be replaced by any of the following types of bearing elements, including but not limited to: jewel bearings; fluid bearings; magnetic bearings; flexure bearings; composite bearings; and polyoxymethylene ("POM") slide bearings. In addition, the ball bearing may be replaced by a swing arm or pivot bearing, in which the bearing element pivots or oscillates on moving and stationary elements.

A magnetic element 37 is disposed at the Hall housing wall 42 to magnetically attract the Hall magnet 32. In some examples, the magnetic element 37 is attached to the flexible printed circuit board 38 using an adhesive. For some embodiments, the flexible printed circuit board 38 is attached to the Hall housing wall 42 using an adhesive. The Hall housing wall 42 is configured to fix components such as a ball bearing and the Hall magnet 32 between the Hall housing wall 42 and the lens holder 300. The Hall sensor 36 is configured to determine the amount of movement of the lens holder 300 from an initial position in the z direction along the optical axis 29 based on a distance between the Hall magnet 32 and the Hall sensor 36. According to some embodiments, the Hall sensor 36 is electrically coupled to a controller or processor on the FPC 38.

The controller or processor implemented in the FPC 38 generates drive signals and supplies them to the SMA wire 80 to which it is connected. The controller or processor also receives an input signal representing a desired position of the lens holder 300 along the optical axis 29 and generates drive signals to drive the lens holder 300 to the desired position. The drive signals can be generated using closed loop control based on the output of the Hall sensor 36, which senses the position of the lens holder 300 along the optical axis 29.

In some embodiments, a receiving space 35 is formed between the Hall housing wall 42 and the lens holder 300. Each receiving space 35 is configured to receive one or more ball bearings. For example, a first receiving space 35A includes ball bearings 31A, 31B, and 31C. Similarly, a second receiving space 35B includes ball bearings 33A, 33B, and 33C. According to some embodiments, the Hall housing wall 42 of the lens holder 300 also includes a receiving space for the Hall magnet 32, which is located between the first and second receiving spaces 35A, 35B.

The first adjacent wall 46 includes a bonding feature 47 at the end at the opening face 43. Similarly, the second adjacent wall 48 includes a bonding feature 49 at the end at the opening face 43. The housing 40 also includes a base bonding feature 45 between the first adjacent wall 46 and the second adjacent wall 48 at the opening face 43. Other embodiments include a housing element 40 that does not include a bonding feature 45. The Hall housing wall 42 includes a bonding feature 52 at a first end and a second bonding feature 51 at a second end opposite the first end.

The engagement feature 52 of the Hall housing wall 42 is configured to couple with the engagement feature 47 of the housing 40. Similarly, the engagement feature 51 of the Hall housing wall 42 is configured to couple with the engagement feature 49 of the housing 40. The Hall housing wall 42 is configured to be fixed to the base engagement feature 45.

The first and second snap-fit frames 50A, 50B are configured to engage the lens holder 300. This is discussed in more detail below with respect to FIG. 3. The first and second snap-fit frames 50A, 50B are secured to the sliding base 60. The sliding base 60 may be formed of metal (e.g., stainless steel) using techniques known in the art. However, those skilled in the art will appreciate that other materials may be used to form the sliding base 60.

In addition, the first snap-fit frame 50A includes a snap-fit arm 59A coupled to the sliding base 60. Similarly, the second snap-fit frame 50B includes a snap-fit arm 59B coupled to the sliding base 60. The sliding base 60 may include a sliding bearing 55, which is configured to minimize any friction between the sliding base 60 and the snap-fit arms 59A, 59B. According to various embodiments of the present invention, the sliding bearing 55 may be formed of polyoxymethylene ("POM"). Those familiar with this technology will understand that other structures may be used to reduce any friction between the snap-fit actuator and the base, such as sliding bearings made of metals such as bronze. The sliding base 60 is configured to be coupled to an assembly base 70 (e.g., an autofocus base of an autofocus assembly).

FIG. 3 illustrates a configuration of one or more ball bearings of an assembly 100 according to an example of the present invention. The lens holder 300 includes a circular frame 320. The circular frame 320 includes a first transverse protruding element 314A and a second transverse protruding element 314B. The first and second transverse protruding elements 314A, 314B each include a respective surface 312, which is aligned with a corresponding section of the first and second transverse walls 46, 48 of the housing 40 (as shown in FIG. 2). According to some embodiments, the first transverse protruding element 314A also includes a pair of engagement elements 310. Only one engagement element 310 is shown, but a person of ordinary skill in the art will understand that a second engagement element 310 extends in the opposite direction of the engagement element 310.

The lens holder 300 is also configured to be placed on the snap-fit frames 50A and 50B. The snap-fit frames 50A and 50B are attached to a sliding base 60. Some examples include a sliding base 60 divided to electrically isolate two sides, one side is generally used as a ground, and the other side is used as a power supply. Other embodiments include a sliding base 60 with two sides electrically coupled to each other.

The snap-fit frames 50A and 50B include snap-fit arms 59A and 59B, respectively. Each snap-fit arm of the snap-fit arm pair 59A and 59B is formed on a separate portion of its respective snap-fit frame 50A and 50B.

As described herein, the snap arms 59A and 59B are configured to move in the z-axis direction when the SMA wire is actuated and deactuated. The snap arms 59A and 59B are configured to engage with the engagement element 310 of the lens holder 300. In some examples, the snap arms 59A and 59B may be configured to engage with other elements of the lens holder 300. For example, the snap arms 59A and 59B may be coupled to each other through a central portion (e.g., a hammock portion) that is configured to support a portion of an object (e.g., the lens holder 300). According to these embodiments, the snap arms 59A and 59B are configured to act on an object to cause it to move. For example, the snap arms are configured to act directly on a feature of a lens holder 300 to push it upward.

The circular frame 320 also includes corner elements 311. Although two corner elements are shown herein, one of ordinary skill in the art will appreciate that the circular frame 320 also includes two additional corner elements 311 at opposite ends of the lens holder 300. The four corner elements 311 are configured to center the lens holder 300 within the housing 40 and along the optical axis 29.

The lens holder 300 includes a first housing element 316A configured to secure the Hall magnet 32. The FPC 38 is also located at a first end of the lens holder 300. The magnetic element 37 is configured so that the Hall magnet 32 attracts the lens holder 300 toward the magnetic element 37, thereby effectively securing one or more ball bearings between the Hall housing wall 42 and the lens holder 300 within the receiving space 35. The FPC 38 includes a plurality of contact pads 39. The contact pads 39 may be gold-plated stainless steel pads configured to power one or more components of the ball bearing autofocus assembly. The Hall housing wall 42 is mechanically coupled to the ball bearing 33 to realize a motion process of moving the ball bearing in the z direction along the optical axis. The first end of the lens holder 300 also includes receiving spaces 35A and 35B formed between the lens holder 300 and the Hall housing wall 42.

The receiving spaces 35A and 35B can be formed into a triangle. In some examples, the Hall housing wall 42 includes a first surface, and the corner element 311A includes a V-groove configured to complete the shape of the triangle. In other examples, the Hall housing wall 42 includes a first surface including a V-groove, and the corner element 311A includes a V-groove aligned with the V-groove of the first surface. In some examples, the receiving spaces 35A and 35B can be lubricated to achieve a low friction environment for the ball bearing. For example, the receiving space 35A can be lubricated to achieve low friction rotation and displacement of the ball bearings 33A, 33B and 33C. Similarly, the receiving space 35B can be lubricated to achieve rotation and displacement of the ball bearings 31A, 31B and 31C.

In addition, lubrication provides a low surface roughness to minimize friction and improve dynamic tilt. In some examples of the present invention, the Hall housing wall 42 and the lens holder 300 (and therefore the corner element) are made of plastic. Forming the receiving spaces 35A and 35B from plastic and lubricating the inner surfaces of the receiving spaces 35A and 35B provides a smooth surface on which the ball can rotate and allows the desired dynamic tilt performance to be achieved.

The location of the ball bearings 31A-31C and 33A-33C relative to the location where the length of the SMA actuator wire 80 applies force to the lens holder 300 helps constrain rotation about an axis normal to a plane containing the optical axis 29. This is because the coupling between the length of the SMA actuator wire 80 and the force applied by the ball bearings 31A-31C and 33A-33C is reduced compared to if the bearings 31A-31C and 33A-33C were located farther away. This effect is ameliorated by the number of ball bearings, which increases the length of the ball bearings along the optical axis 29. Therefore, embodiments of the guided bearing autofocus assembly have better performance than current autofocus assemblies, resulting in a more efficient assembly with improved image quality.

The sliding base 60 includes contact pads 62A and 62B. The contact pads 62A and 62B may be gold-plated stainless steel pads that are configured to power the SMA wire 80. This is discussed in more detail below with respect to FIGS. 4 and 5.

FIG. 4 illustrates an exemplary circuit design of SMA wires 80A and 80B of an assembly 100 according to an example of the present invention. SMA wires 80A and 80B are wired in series. For example, power 331 may be provided via contact pad 62A to power SMA wires 80A, 80B. Current flows along SMA wire 80A in direction 332A and enters the sliding base 60 along current flow direction 332B. The current flows along SMA wire 80B in direction 332C and enters the sliding base 60 along current flow direction 332D. Finally, the current flows to contact pad 62B. Therefore, the same current applied to SMA wire 80A is also applied to SMA wire 80B. By applying the same current through SMA wires 80A and 80B, more uniform heat can be applied to the two wires. Applying more uniform heat to SMA wires 80A and 80B reduces the imbalance of the force applied by the snap actuator to the two sides of the lens holder and reduces dynamic tilt, which results in better image quality across all pixels of an image sensor.

FIG. 5 illustrates an exemplary circuit design of SMA wires 80A and 80B of an assembly 100 according to an example of the present invention. In some examples, SMA wires 80A and 80B are wired in parallel. For example, power 231 may be provided via contact pad 62B to power SMA wires 80A, 80B. Current flows along SMA wire 80A in direction 231A and into the sliding base 60 along current flow direction 231C. Current also flows into the sliding base 60 in direction 232D, along SMA wire 80B in direction 232C, along SMA wire 80B in direction 232B, and into the sliding base 60 along current flow direction 231C. Finally, the current flows to contact pad 62A.

The amount of heat to the SMA wires 80A and 80B depends on the resistance change caused by the manufacturing of the SMA wire length. Therefore, each side can push the lens holder 300 with a different force, making the assembly 100 of Figure 5 more susceptible to tilting. However, the ball bearing configuration disclosed herein mitigates this tilting change, making it not a problem.

FIG. 6 illustrates an actuator assembly 600 according to an alternative embodiment of the present invention. The actuator assembly 600 also includes a first actuator frame 630 and a second actuator frame 640. The actuator assembly 600 may include an SMA wire 610 and an SMA wire 620. The actuator assembly 600 also includes a power supply 650 and a ground 660. The actuator assembly 600 may include, but is not limited to, snap-fit actuators, bi-piezoelectric chip actuators, and other SMA actuators. In some embodiments, the actuator assembly 600 is a snap-fit wire actuator.

The following example of the present invention achieves optimized current flow through the SMA wires of the actuator assembly 600. This example provides at least one isolated conductor circuit with one isolated metal crimp pad for serially attaching the SMA wires, which allows equal current to flow through both wires in directions 601 to 604. This is the best way to achieve equal thrust on both sides of the actuator assembly 600 when powered by a single source. This is discussed in more detail below.

FIG7 is a side view of an actuator assembly 600 according to one embodiment of the present invention receiving a lens holder 300. A current may be input into the SMA wire of the actuator assembly 600, which heats and contracts the SMA wire, which drives the lens holder 300 upward. A spring (not shown) may be provided to return the lens holder 300 downward.

FIG8 is an isometric side view of an actuator assembly 600 receiving a lens holder 300 according to an embodiment of the present invention. The actuator assembly 600 includes a first actuator frame 630 and a second actuator frame 640. In some embodiments, the first actuator frame 630 and the second actuator frame can be configured as first and second snap-fit frames, respectively. The first actuator frame 630 includes a first actuator arm 631. In some embodiments, the first actuator arm 631 can be configured as a first snap-fit arm. The first actuator arm 631 of the first actuator frame 630 extends toward the second actuator frame 640. The second actuator frame 640 similarly includes a first actuator arm 641. The first actuator arm 641 of the second actuator frame 640 extends toward the first actuator frame 640. The first actuator arms 631 , 641 of the first and second actuator frames 630 , 640 are connected by an SMA wire 620 .

The first actuator frame 630 includes a second actuator arm 632. The second actuator arm 632 can be configured as a second snap-on arm. The second actuator arm 632 of the first actuator frame 630 extends toward the second actuator frame 640. The second actuator frame 640 similarly includes a second actuator arm 642. The second actuator arm 642 of the second actuator frame 640 extends toward the first actuator frame 640. The second actuator arms 632, 642 of the first and second actuator frames 630, 640 are connected by a second SMA wire.

The first actuator arms 631 , 641 and the second actuator arms 632 , 642 of the first and second actuator frames 630 , 640 are configured to engage with the lens holder 300 , as described in FIG. 2 .

FIG. 9 illustrates a force applied to the lens holder 300 by the actuator assembly 600 according to an example of the present invention. The first actuator arms 631, 641 and the second actuator arms 632, 642 of the actuator assembly 600 apply an upward force to the lens holder 300. Specifically, the first actuator arms 631, 641 provide an upward force 611 to the lens holder 300. Similarly, the second actuator arms 632, 642 provide an upward force 612 to the lens holder 300. The upward force 611 and the upward force 612 are generated using SMA wires 620 and 610, respectively. In some examples, the upward force 611 and the upward force 612 are equal.

When the upward forces 611, 612 generated by the SMA wires 620 and 610 are not equal, excessive torque may be generated, inducing the lens holder 300 to tilt, which may cause image distortion or blurring of a captured image.

FIG10 shows a side view of the lens holder 300 assembled with the actuator wire actuator assembly 600. As can be seen in the figure, the first actuator arms 631, 641 are in contact with the lens holder 300.

FIG. 11 shows an exploded view of an actuator wire actuator assembly 600 according to an embodiment of the present invention. FIG. 12 shows an assembled view of the actuator assembly 600 according to an embodiment of the present invention. The actuator assembly 600 includes the first actuator frame 630, the second actuator frame 640. The actuator assembly 600 also includes a base 670. The base 670 is configured to receive the first actuator frame 630 and the second actuator frame 640 opposite to the first actuator frame 630. The actuator assembly 600 also includes SMA wires 620, 610. The actuator assembly 600 also includes flat sliding bearings 675A, 675B, 675C and 675D located at each corner of the base 670. Each flat sliding bearing 675A, 675B, 675C and 675D is configured to act as a mechanical element that constrains relative motion to only the intended motion and reduces friction between moving parts.

In some examples, the SMA wires 620, 610 are configured in series to achieve equal current across both wires from a single power source. When both SMA wires 620, 610 receive an equal current, the wires experience equal heat and therefore actuate equally (expand or contract). As a result, force deviations on either side of the actuator are minimized. This minimizes lens tilt and reduces image distortion of the camera image.

In some embodiments, the first and second actuator frames 630, 640 are made of a single metal material. In other embodiments, the first and second actuator frames 630, 640 are made of a metal material with isolated conductors attached. The isolated conductors will be discussed in detail.

13 shows a current path across the actuator assembly 600 according to an embodiment of the present invention. Specifically, the current path includes a power input 1305, a path 1306 along a first isolation conductor, a path 1302 along a first SMA line, a path 1301 along a single metal actuator frame, a path 1307 along a second SMA line, a path 1303 along a second isolation conductor, and a ground output 1304.

Current enters the actuator assembly 600 at power input 1305. The current then passes through a first isolation conductor along path 1306, which is electrically connected to the power input 1305. Once the current passes through an isolation conductor along path 1306, the current passes through a first SMA wire along path 1302. The first SMA wire is electrically connected to the first isolation conductor. Once the current passes through the first SMA wire along path 1302, the current passes through the single metal actuator frame along path 1301. The first SMA wire is electrically connected to the single metal actuator frame. Once the current passes through the single metal actuator frame along path 1301, the current passes through the second SMA wire along path 1307. The second SMA wire is also electrically connected to the single metal actuator frame. The current then passes through a second isolation conductor along path 1303, which is electrically connected to the second SMA wire. Once the current passes through the second isolation conductor along path 1303, the current passes through the ground output 1304.

As shown in FIG. 13 , the first and second SMA wires are configured in series to achieve equal current across the two wires from a single source (i.e., the power input 1305). In some examples, the equal current applied across the first and second SMA wires along paths 1302 and 1307, respectively, is equivalent to equal heat conducted at the first and second SMA wires. In some examples, the minimum force deviation on each side of the actuator minimizes lens tilt and reduces image distortion of the camera image. The first actuator frame with path 1301 can be configured as a metal single body structure. The other actuator frame is metal with an isolated conductor (not shown) attached.

FIG. 14 illustrates an actuator frame 640 and a circuit 680 of an actuator assembly 600 according to an embodiment of the present invention. In some embodiments, the actuator frame 640 can be configured as a snap-on frame 640. Specifically, FIG. 14 illustrates all layers of the actuator frame 640 and the circuit 680. In some embodiments, a protective cover coating (not shown) can be provided on top of the conductor layers of the circuit 680. The actuator frame 640 also includes a first isolation conductor 1401 and a second isolation conductor 1402. The first and second isolation conductors 1401, 1402 can be implemented to complete the current path as described with respect to FIG. 13. The first and second isolated conductors 1401, 1402 may include vias to the isolated metal pads to electrically connect the first and second isolated conductors 1401, 1402 to the first and second SMA wires of Figure 13. This will be discussed in more detail below with respect to Figure 18.

In some examples, the first and second SMA wires of FIG13 can be attached to the first and second isolated conductors 1401, 1402, respectively. The first and second SMA wires can be crimped to the first and second isolated conductors 1401, 1402 by resistance welding crimping or mechanical crimping.

FIG. 15 shows an exploded view of an actuator frame 640 having first and second isolation conductors 1401, 1402 according to an embodiment of the present invention. The actuator frame 640 includes a first isolation conductor circuit 682, a second isolation conductor circuit 684, and a metal actuator frame layer 688. In some embodiments, the metal actuator frame layer 688 can be configured as a metal snap-fit frame layer. The actuator frame 640 also includes an insulator layer 686 sandwiched between the first and second isolation conductor circuits 682, 684 and the metal actuator frame layer 688. In some embodiments, a protective cover coating can be provided on top of the first and second isolation conductors 1401, 1402.

FIG. 16 shows a top view of an actuator frame 640 according to an example of the present invention. The actuator frame 640 may include first and second isolation conductors 1401, 1402. The actuator frame 640 may include a first through hole 681B adjacent to the first isolation conductor 1401. In addition, the actuator frame 640 may include a second through hole 681A adjacent to the second isolation conductor 1402. The first and second through holes 681B, 681A are through holes or apertures in an insulating layer (e.g., 686 in FIG. 15) that expose at least a portion of an isolation metal pad. The actuator frame 640 may also include electrical pads 683A, 683B configured to electrically connect the actuator frame 640 to a power input and ground output (1305 and 1304 in FIG. 13).

17 shows a bottom view of an actuator frame 640 according to an example of the present invention. The first isolation conductor 1401 is attached to a first SMA wire, as discussed herein. The second isolation conductor 1402 is attached to a second SMA wire, as discussed herein.

FIG. 18 shows that the second actuator frame 640 similarly includes a second actuator arm 642. In some examples, the second actuator arm 642 can be configured as a second snap-on arm. FIG. 18 also shows an isolation conductor through hole 688 according to an example of the present invention. FIG. 18 also shows that the SMA wire 610 is attached to the isolation conductor 1939 using an SMA wire crimp 1801. Thus, in some examples, the isolation conductor 1939 is a connection joint or crimp location to the SMA wire 610. In some examples, the SMA wire crimp 1801 can be configured as a resistance weld or a mechanical crimp crimp.

19 shows a cross-sectional view of an isolated conductor via 688 to an isolated metal pad according to an embodiment of the present invention. The via extends through the conductor layer 1940, the insulator layer 1941, and to the metal pad layer 1901.

FIG. 20 illustrates a modular snap-fit circuit assembly 2000 according to an example of the present invention. FIG. 21 illustrates a modular snap-fit circuit assembly 2000. The modular snap-fit circuit assembly 2000 includes a first actuator frame 2001 and a second actuator frame 2002. In some examples, the first actuator frame 2001 and the second actuator frame 2002 can be configured as a first and second snap-fit frame, respectively. The modular snap-fit circuit assembly 2000 also includes a metal base 2004 to which the first and second actuator frames 2001, 2002 are attached. The modular snap-fit circuit assembly 2000 also includes a first SMA wire 2010 and a second SMA wire 2020. The modular snap-on circuit assembly 2000 also includes a first actuator circuit 2030 and a second actuator circuit 2040, which are configured to attach to and actuate the second actuator frame 2002. In some examples, the first actuator circuit 2030 and the second actuator circuit 2040 can be configured as first and second snap-on circuits, respectively. The first actuator frame 2001 can also include a first and second actuator circuit (not shown) configured to attach to and actuate the first actuator frame 2001.

FIG. 22A illustrates a first and a second modular actuator circuit 2030 and 2040 of a modular snap-fit circuit assembly according to an embodiment of the present invention. FIG. 22B illustrates a bottom view of the first and the second modular actuator circuit 2030 and 2040 according to an embodiment of the present invention. The first modular actuator circuit 2030 may include an isolation metal pad 2034 for attachment to an SMA wire (not shown). The isolation metal pad 2034 may be made of steel or any other type of suitable metal. The first modular actuator circuit 2030 may also include an electrical pad 2032. The second modular actuator circuit 2040 may include an isolation metal pad 2044 for attachment to an SMA wire (not shown). The isolation metal pad 2044 can be made of steel or any other type of suitable metal. The second modular actuator circuit 2040 can also include an electrical pad 2042.

The first and second modular actuator circuits 2030 and 2040 enable a higher panel density of modular snap-fit circuit assemblies. The first and second modular actuator circuits 2030 and 2040 also enable the same modular circuit assembly to be manufactured and placed on a variety of camera sizes without redesigning or rebuilding the circuit. In addition, the first and second modular actuator circuits 2030 and 2040 are configured to be attached to an actuator frame having a single metal component. In some examples, the first and second modular actuator circuits 2030 and 2040 have isolated metal pads 2034, 2044 to crimp SMA wires thereto (resistance welding or fold crimping). Although two modular actuator circuits are shown herein, the actuator frames can also be attached to a single modular circuit design.

FIG. 23 shows an exploded view of multiple circuit layers of the first modular actuator circuit 2030 according to an example of the present invention. FIG. 24 shows an assembled view of multiple circuit layers of the first modular actuator circuit 2030 according to an example of the present invention. The first modular snap-fit circuit 2030 includes an isolated conductor layer 2031, an insulator layer 2033, and a metal layer 2035. The first modular snap-fit circuit 2030 also includes an isolated metal pad 2037 for attachment to an SMA wire (not shown).

The isolation conductor layer 2031 may be directly connected to the isolation metal pad 2037. For example, the isolation conductor layer 2031 may be directly plated to the isolation metal pad 2037. In other examples, the isolation conductor layer 2031 may be welded to the isolation metal pad 2037. In alternative examples, a conductive epoxy may be applied between the isolation conductor layer 2031 and the isolation metal pad 2037. In certain alternative examples, the isolation conductor layer 2031 may be laser or resistance welded to the isolation metal pad 2037.

The insulator layer 2033 may be directly connected to the metal layer 2035. For example, the insulator layer 2033 may be formed on top of the metal layer 2035, followed by the isolation conductor layer 2031 and the cover coating; each layer is formed in an additional process. In some alternative embodiments of the present invention, the insulator layer 2033 may be glued to the metal layer 2035 at at least one location. In some alternative embodiments, the insulator layer 2033, the isolation conductor layer 2031 and (several) cover coatings may be constructed as a separate flexible circuit component and glued to the metal layer 2035.

Both the actuator assembly 600 with isolated conductors (of FIG. 13 ) and the modular snap-fit circuit assembly 2000 (of FIG. 20 ) implement serial attachment of two SMA wires to minimize force differences between the wires when driven by a single source. The modular snap-fit circuit assembly 2000 is a more compact circuit design that does not require size changes when implemented in camera platforms of various sizes. In some embodiments, the isolation metal pad is used as a connection point between the isolation circuit and the SMA wire. Due to the high tensile force of the SMA wire, this isolation metal pad is rigidly connected to the metal actuator frame. Therefore, in some embodiments, the isolation metal pad is formed as a press connection to the SMA wire.

Both the actuator assembly 600 with isolated conductors (of FIG. 13 ) and the modular snap-fit circuit assembly 2000 (of FIG. 20 ) can be constructed using additive circuit techniques. For example, an insulator layer is formed on top of a metal layer, a conductive material is formed on top of the insulator, and then a protective cover coating is formed. In some alternative embodiments, the insulator layer, the conductor layer, and the cover coating(s) can be formed separately and then attached to the metal layer using an adhesive.

It should be understood that terms such as "top", "bottom", "above", "below", and the x-, y-, and z-directions as used herein are merely for convenience and refer to the spatial relationship of components relative to each other, rather than any particular spatial or gravitational orientation. Thus, such terms are intended to encompass an assembly of component parts regardless of whether the assembly is oriented in the particular orientation shown in the figures and described in the specification, inverted from that orientation, or in any other rotational variation.

It should be understood that the term "present invention" as used herein should not be interpreted as referring to a single invention having only a single essential element or group of elements. Similarly, it should also be understood that the term "present invention" encompasses multiple independent innovations that can each be considered an independent invention. Although the present invention has been described in detail with respect to its preferred embodiments and drawings, those skilled in the art will understand that various adaptations and modifications can be made to the embodiments of the present invention without departing from the spirit and scope of the present invention. In addition, the techniques described herein can be used to make a device having two, three, four, five, six or more (collectively referred to as n) dual piezoelectric chip actuators and snap-on actuators. Therefore, it should be understood that the detailed description and accompanying drawings as set forth above are not intended to limit the breadth of the present invention, which should be inferred only from the scope of the accompanying invention claims and their properly interpreted legal equivalents.

9: Cover 20: Spring element 29: Optical axis 31A: Ball bearing 31B: Ball bearing 31C: Ball bearing 32: Hall magnet 33A: Ball bearing 33B: Ball bearing 33C: Ball bearing 35A: First receiving space 35B: Second receiving space 36: Hall sensor 37: Magnetic element 38: Flexible printed circuit board (FPC) 39: Contact pad 40: Housing element/housing 41: Receiving space 42: Hall housing wall 42B: Aperture 43: Opening surface 44: Center wall 45: Base joint feature 46: First adjacent wall 47: Joint feature 48: Second adjacent wall 49: Joint feature 50A: First snap-fit frame 50B: Second snap-fit frame 51: Second joint feature 52: Joint feature 55: Sliding bearing 59A: Snap-fit arm 59B: Snap-fit arm 60: Sliding base 62A: Contact pad 62B: Contact pad 70: Assembly base 80A: SMA wire 80B: SMA wire 100: Guided autofocus assembly 231: Power supply 231A: Direction 231C: Direction 232B: Direction 232C: Direction 232D: Direction 300: Lens bracket 310: Engagement element 311A: Corner element 311B: Corner element 312A: Surface 314A: First transverse protrusion element 314B: Second transverse protrusion element 316A: First housing element 320: Circular frame 331: Power supply 332A: Direction 332B: Direction 332C: Direction 332D: Direction 600: Actuator assembly 601: Direction 602: Direction 603: Direction 604: Direction 610: SMA wire 611: Upward force 612: Upward force 620: SMA wire 630: First actuator frame 631: First actuator arm 632: Second actuator arm 640: Second actuator frame 641: First actuator arm 642: Second actuator arm 650: Power supply 660: Ground potential 670: Base 675A: Flat sliding bearing 675B: Flat sliding bearing 675C: Flat sliding bearing 675D: Flat sliding bearing 680: Circuit 681A: Through hole 681B: Through hole 682: First isolation conductor circuit 683A: Electrical pad 683B: Electrical pad 684: Second isolation conductor circuit 686: Insulator layer 688: Metal actuator frame layer/isolation conductor through hole 1301: Path 1302: Path 1303: Path 1304: Ground output 1305: Power input 1306: Path 1307: Path 1401: First isolation conductor 1402: Second isolation conductor 1801: SMA wire crimping 1901: Metal pad layer 2000: Modular snap-fit circuit assembly 2001: First actuator frame 2002: Second actuator frame 2004: Metal base 2010: First SMA wire 2020: Second SMA wire 2030: First actuator circuit/first modular actuator circuit 2031: Isolation conductor layer 2032: Electrical pad 2033: Insulation layer 2034: Isolation metal pad 2035: Metal layer 2040: Second actuator circuit/second modular actuator circuit 2042: Electrical pad 2044: Isolation metal pad

Embodiments of the invention are illustrated by way of example and not limitation in the figures of the accompanying drawings in which like reference numerals refer to like elements and in which:

FIG1 shows a ball bearing automatic focusing assembly according to an embodiment of the present invention;

FIG. 2 is an exploded view of the ball bearing automatic focusing assembly of FIG. 1 according to an embodiment of the present invention;

FIG. 3 illustrates a configuration of a ball bearing engaging with an automatic focusing assembly according to an embodiment of the present invention;

FIG. 4 shows a circuit design of an SMA line of a ball bearing buckled automatic focus assembly according to an embodiment of the present invention;

FIG. 5 shows a circuit design of an SMA line of a ball bearing buckled automatic focus assembly according to an embodiment of the present invention;

FIG6 illustrates an actuator assembly according to an alternative embodiment of the present invention;

FIG. 7 is a side view of the actuator assembly of FIG. 6 receiving the lens bracket of FIG. 2 according to an embodiment of the present invention;

FIG8 is an isometric side view of the actuator assembly of FIG6 receiving the lens support of FIG2 according to an embodiment of the present invention;

FIG. 9 illustrates a force applied by the actuator assembly of FIG. 6 to the lens support of FIG. 2 according to an embodiment of the present invention;

FIG. 10 illustrates the lens support of FIG. 2 assembled on the actuator assembly of FIG. 6 according to one embodiment of the present invention;

FIG. 11 is an exploded view of the actuator assembly of FIG. 6 according to an embodiment of the present invention;

FIG. 12 is an assembly diagram of the actuator assembly of FIG. 6 according to an embodiment of the present invention;

FIG. 13 illustrates a current path across the actuator assembly of FIG. 6 according to an embodiment of the present invention;

FIG. 14 illustrates a snap-fit frame and a circuit of the actuator assembly of FIG. 6 according to an embodiment of the present invention;

FIG. 15 illustrates an actuator frame with isolated conductors according to an embodiment of the present invention;

FIG. 16 illustrates a top view of the actuator frame of FIG. 15 according to an embodiment of the present invention;

FIG. 17 illustrates a bottom view of the actuator frame of FIG. 15 according to an embodiment of the present invention;

FIG. 18 shows an isolated conductor via to an isolated metal pad according to an embodiment of the present invention;

FIG. 19 is a cross-sectional view of the isolated conductor via to metal of FIG. 18 according to an embodiment of the present invention;

FIG. 20 shows a modular circuit assembly according to an embodiment of the present invention;

FIG. 21 illustrates a modular circuit assembly according to an embodiment of the present invention;

FIG. 22A shows a modular circuit of a modular circuit assembly according to an embodiment of the present invention;

FIG. 22B illustrates a bottom view of a modular circuit of a modular circuit assembly according to an embodiment of the present invention;

FIG. 23 illustrates an exploded view of multiple circuit layers of a modular circuit assembly according to an embodiment of the present invention; and

FIG. 24 shows an assembly diagram of multiple circuit layers of a modular circuit assembly according to an embodiment of the present invention.

9: Cover

20: Spring element

29: Light axis

31A: Ball bearing

31B: Ball bearing

32: Hall magnet

33A: Ball bearing

33B: Ball bearing

33C: Ball bearing

35A: First receiving space

35B: Second receiving space

36: Hall sensor

37: Magnetic components

38: Flexible printed circuit board (FPC)

40: Shell components

41: Receiving space

42: Hall's outer shell

42B: Porosity

43: Opening surface

44: Center wall

45: Base joint features

46: First neighbor

47:Joint features

48: Second phase neighbor

49:Joint features

50A: First buckle frame

50B: Second buckle frame

51: Second bonding feature

52:Joint features

55: Sliding bearing

59A: snap-fit arm

59B: snap-fit arm

60: Sliding base

70: Assembly base

80A:SMA cable

80B:SMA cable

100:Actuator assembly

300: Lens bracket

Claims (20)

A snap wire actuator assembly comprising: At least one snap frame mounted on a base of the snap wire actuator assembly and including at least one isolated conductor; A first SMA wire electrically connected to one of the at least one isolated conductor; and A second SMA wire opposite the first SMA wire, wherein the first and second SMA wires are configured in series so that both the first and second SMA wires can receive equal current from a current input. A snap-line actuator assembly as claimed in claim 1, wherein the at least one snap-line frame comprises a first and a second snap-line frame mounted on the base of the snap-line actuator assembly. A snap-on wire actuator assembly as claimed in claim 2, wherein the second snap-on frame comprises a single piece of metal material electrically connected to the first and second SMA wires. The latching line actuator assembly of claim 2 further comprises at least one flat sliding bearing positioned at each corner of the base, and each flat sliding bearing is configured to constrain the relative motion between the moving components and reduce friction. A snap wire actuator assembly as in claim 2, wherein the at least one snap frame further comprises a second isolated conductor electrically connected to the second SMA wire. A snap-wire actuator assembly as in claim 5, wherein the second SMA wire is crimped to the second isolation conductor using at least one of a resistance welding crimp or a mechanical crimp. As in the snap-fit wire actuator assembly of claim 5, wherein a current is transmitted through the second isolation conductor of the at least one snap-fit frame to a ground output. A snap wire actuator assembly as in claim 1, wherein the current input is configured to receive a current that is passed through the at least one isolated conductor to the first SMA wire. A snap-wire actuator assembly as in claim 1, wherein the first SMA wire is crimped to one of the at least one isolated conductor using at least one of a resistance welding crimp or a mechanical crimp. A snap-fit wire actuator assembly as claimed in claim 1, wherein the at least one snap-fit frame includes at least one isolation conductor circuit, a metal snap-fit frame layer and an insulating layer between the at least one isolation conductor circuit and the metal snap-fit frame layer. A snap-fit wire actuator assembly as in claim 10, wherein the at least one snap-fit frame includes at least one electrical via extending through the insulating layer to the at least one isolated conductor. A snap-fit wire actuator assembly as claimed in claim 10, wherein the at least one snap-fit frame includes a protective covering coating disposed on the at least one isolation conductor circuit. A snap-fit wire actuator assembly as claimed in claim 10, wherein the at least one snap-fit frame further includes a first electrical through hole adjacent to a first isolation conductor and a second through hole adjacent to a second isolation conductor. A snap wire actuator assembly comprising: At least one snap frame mounted on a base of the snap wire actuator assembly; A first SMA wire electrically connected to the at least one snap frame; and A second SMA wire opposite the first SMA wire, wherein the first and second SMA wires are configured in series so that both the first and second SMA wires can receive equal current from a current input. A snap-fit wire actuator assembly as in claim 14, wherein the at least one snap-fit frame comprises at least one isolated conductor. A snap-wire actuator assembly as in claim 15, wherein the first SMA wire is electrically connected to the at least one isolated conductor. A snap-wire actuator assembly as in claim 16, wherein the first SMA wire is crimped to one of the at least one isolated conductor using at least one of a resistance welding crimp or a mechanical crimp. The fastening line actuator assembly of claim 14 further comprises a second fastening frame mounted on the base of the fastening line actuator assembly, opposite to the first fastening frame. A snap-line actuator assembly as claimed in claim 18, wherein the at least one snap-line frame comprises a first and a second snap-line frame mounted on the base of the snap-line actuator assembly. A snap-wire actuator assembly as in claim 19, wherein the second SMA wire is crimped to the second isolation conductor using at least one of a resistance welding crimp or a mechanical crimp.