Shape memory alloy actuator and method thereof

Abstract

An SMA actuator and associated methods are described. One embodiment of the actuator includes a base, a plurality of buckle arms, and at least a first shape memory alloy wire coupled to a pair of buckle actuators of the plurality of buckle arms. Another embodiment of the actuator includes a base and at least one bimorph actuator including a shape memory alloy material. The bimorph actuator is coupled to the base.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present invention relate to the field of shape memory alloy systems, and more particularly, to the field of shape memory alloy actuators and related methods. [Background technology]

[0002] Shape memory alloy ("SMA") systems have a movable assembly or structure that can be used, for example, with a camera lens element as an autofocus drive mechanism. These systems can be enclosed by a structure such as a shielding can. The movable assembly is supported for movement on a support assembly by bearings such as a plurality of balls. A flexure element formed from a metal such as phosphor bronze or stainless steel has a movable plate and a flexure. The flexure extends between the movable plate and the fixed support assembly and acts as a spring to allow movement of the movable assembly relative to the fixed support assembly. The balls allow the movable assembly to move with little resistance. The movable assembly and the support assembly are connected by four shape memory alloy (SMA) wires that extend between them. Each of the SMA wires has one end attached to the support assembly and an opposite end attached to the movable assembly. An electrical drive signal is applied to the SMA wires to actuate the suspension. However, these types of systems suffer from system complexity resulting in a bulky system requiring a large footprint and large height clearance. Additionally, current systems are unable to provide a high Z stroke range in a small, low profile footprint. Summary of the Invention [Means for solving the problem]

[0003] SMA actuators and associated methods are described. One embodiment of the actuator includes a base, a plurality of buckle arms, and at least a first shape memory alloy wire coupled to a pair of the buckle arms of the plurality of buckle arms. Another embodiment of the actuator includes a base and at least one bimorph actuator comprising a shape memory alloy material. The bimorph actuator is attached to the base.

[0004] Other features and advantages of embodiments of the present invention will be apparent from the accompanying drawings and from the detailed description that follows. Embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference symbols refer to similar elements and in which: [Brief description of the drawings]

[0005] [Figure 1a] 1 illustrates a lens assembly including an SMA actuator configured as a buckle actuator, according to one embodiment. [Figure 1b] 1 illustrates an SMA actuator according to one embodiment. [Diagram 2] 1 illustrates an SMA actuator according to one embodiment. [Diagram 3] FIG. 1 illustrates an exploded view of an autofocus assembly including an SMA wire actuator according to one embodiment. [Figure 4] 1 illustrates an autofocus assembly including an SMA actuator according to one embodiment. [Diagram 5] 1 illustrates an SMA actuator including a sensor according to one embodiment. [Figure 6] 1A-1D show top and side views of an SMA actuator configured as a buckle actuator according to one embodiment with a lens carriage attached. [Figure 7] FIG. 2 shows a side view of a section of an SMA actuator according to one embodiment. [Figure 8] 1A-1C show multiple views of one embodiment of a buckle actuator. [Figure 9]1 illustrates a bimorph actuator with a lens carriage according to one embodiment. [Figure 10] FIG. 1 illustrates a cutaway view of an autofocus assembly including an SMA actuator according to one embodiment. [Figure 11a] 1A-1D show diagrams of bimorph actuators according to some embodiments. [Figure 11b] 1A-1D show diagrams of bimorph actuators according to some embodiments. [Figure 11c] 1A-1D show diagrams of bimorph actuators according to some embodiments. [Figure 12] 1 illustrates a diagram of an embodiment of a bimorph actuator, according to one embodiment. [Figure 13] 1 illustrates a cross section of an end pad of a bimorph actuator according to one embodiment. [Figure 14] 1 illustrates a cross section of a central power pad of a bimorph actuator according to one embodiment. [Figure 15] 1 illustrates an exploded view of an SMA actuator including two buckle actuators according to one embodiment. [Figure 16] 1 illustrates an SMA actuator including two buckle actuators according to one embodiment. [Figure 17] FIG. 1 illustrates a side view of an SMA actuator including two buckle actuators according to one embodiment. [Figure 18] FIG. 1 illustrates a side view of an SMA actuator including two buckle actuators according to one embodiment. [Figure 19] 1 illustrates an exploded view of an assembly including an SMA actuator that includes two buckle actuators according to one embodiment. [Figure 20] 1 illustrates an SMA actuator including two buckle actuators according to one embodiment. [Figure 21] 1 illustrates an SMA actuator including two buckle actuators according to one embodiment. [Figure 22] 1 illustrates an SMA actuator including two buckle actuators according to one embodiment. [Diagram 23] 1 illustrates an SMA actuator including two buckle actuators and a coupler according to one embodiment. [Figure 24] 1 illustrates an exploded view of an SMA system including an SMA actuator including a buckle actuator with a laminate hammock, according to one embodiment. [Diagram 25] 24 shows an SMA system including an SMA actuator including a buckle actuator 2402 with a laminate hammock, according to one embodiment. [Figure 26] 1 illustrates a buckle actuator including a laminate hammock according to one embodiment. [Figure 27] 1 illustrates a laminate hammock of an SMA actuator according to one embodiment. [Figure 28] 1 illustrates a laminate molded crimp connection for an SMA actuator according to one embodiment. [Figure 29] 1 shows an SMA actuator including a buckle actuator with a laminate hammock. [Diagram 30] 1 illustrates an exploded view of an SMA system including an SMA actuator, including a buckle actuator, according to one embodiment. [Diagram 31] 1 illustrates an SMA system including an SMA actuator, including a buckle actuator, according to one embodiment. [Diagram 32] 1 illustrates an SMA actuator including a buckle actuator according to one embodiment. [Diagram 33] 1 illustrates a two-yoke capture joint of a pair of buckle arms of an SMA actuator according to one embodiment. [Diagram 34] 13 illustrates a resistance weld crimp for an SMA actuator according to one embodiment, used to attach the SMA wire to a buckle actuator. [Diagram 35] 1 shows an SMA actuator including a buckle actuator with a two yoke capture joint. [Diagram 36] 1 illustrates an SMA bimorph liquid lens according to one embodiment. [Figure 37] 1 illustrates an SMA bimorph liquid lens viewed obliquely from above according to one embodiment. [Figure 38] 1A-1D show cross-sectional and bottom views of an SMA bimorph liquid lens according to one embodiment. [Figure 39] 1 illustrates an SMA system including an SMA actuator with a bimorph actuator according to one embodiment. [Diagram 40] 1 illustrates an SMA actuator with a bimorph actuator according to one embodiment. [Diagram 41] The length of the bimorph actuator and the location of the bond pads where the SMA wire extends the wire length beyond the bimorph actuator are shown. [Diagram 42] FIG. 1 illustrates an exploded view of an SMA system including a bimorph actuator according to one embodiment. [Diagram 43] 1 illustrates an exploded view of a subsection of an SMA actuator according to one embodiment. [Diagram 44] 1 illustrates a subsection of an SMA actuator according to one embodiment. [Diagram 45] 1 illustrates a five-axis sensor shifting system according to one embodiment. [Figure 46] 1 illustrates an exploded view of a five-axis sensor shifting system according to one embodiment. [Figure 47] 1 shows an SMA actuator according to one embodiment, including a bimorph actuator incorporated in the circuit for all movements. [Figure 48] 1 shows an SMA actuator according to one embodiment, including a bimorph actuator incorporated in the circuit for all movements. [Figure 49] 1 illustrates a cross section of a five-axis sensor shifting system according to one embodiment. [Figure 50] 1 illustrates an SMA actuator according to an embodiment, including a bimorph actuator. [Figure 51]13A-13C show top views of an SMA actuator according to one embodiment, including a bimorph actuator that displaces an image sensor at different x and y positions. [Figure 52] 1 illustrates an SMA actuator including a bimorph actuator configured as a box bimorph autofocus according to one embodiment. [Figure 53] 1 illustrates an SMA actuator including a bimorph actuator according to one embodiment. [Figure 54] 1 illustrates an SMA actuator including a bimorph actuator according to one embodiment. [Figure 55] 1 illustrates an SMA actuator including a bimorph actuator according to one embodiment. [Figure 56] 1 illustrates an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 57] 1 shows an exploded view of an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator configured as a two-axis lens-shifting OIS. [Figure 58] 1 illustrates a cross section of an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator configured as a two-axis lens shifting OIS. [Figure 59] 1 illustrates a box bimorph actuator according to one embodiment. [Figure 60] 1 illustrates an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 61] 1 shows an exploded view of an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 62] 1 illustrates a cross section of an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 63] 1 illustrates a box bimorph actuator according to one embodiment. [Figure 64]1 illustrates an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 65] 1 shows an exploded view of an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 66] 1 illustrates an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 67] 1 illustrates an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 68] 1 illustrates an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 69] 1 illustrates an exploded view of an SMA including SMA actuator according to one embodiment, including a bimorph actuator. [Figure 70] 1 illustrates a cross section of an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator configured as a three-axis sensor-shifting OIS. [Figure 71] 1 illustrates a box bimorph actuator component according to one embodiment. [Figure 72] 1 illustrates a flexible sensor circuit for use in an SMA system according to one embodiment. [Figure 73] 1 illustrates an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 74] 1 shows an exploded view of an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 75] 1 illustrates a cross section of an SMA system including an SMA actuator according to one embodiment. [Figure 76] 1 illustrates a box bimorph actuator according to one embodiment. [Figure 77] 1 illustrates a flexible sensor circuit for use in an SMA system according to one embodiment. [Figure 78]1 illustrates an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 79] 1 shows an exploded view of an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 80] 1 illustrates a cross section of an SMA system including an SMA actuator according to one embodiment. [Figure 81] 1 illustrates a box bimorph actuator according to one embodiment. [Figure 82] 1 illustrates a flexible sensor circuit for use in an SMA system according to one embodiment. [Figure 83] 1 illustrates an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 84] FIG. 1 illustrates an exploded view of an SMA system including an SMA actuator according to one embodiment. [Figure 85] 1 illustrates a cross section of an SMA system including an SMA actuator according to one embodiment, including a bimorph actuator. [Figure 86] 1 illustrates a box bimorph actuator for use in an SMA system according to one embodiment. [Figure 87] 1 illustrates a flexible sensor circuit for use in an SMA system according to one embodiment. [Figure 88] 13 illustrates exemplary dimensions for a bimorph actuator of an SMA actuator according to one embodiment. [Figure 89] 1 illustrates a lens system for a folded camera according to one embodiment. [Figure 90] 1 illustrates several embodiments of a lens system including a liquid lens according to one embodiment. [Figure 91] 1 illustrates a folding lens, which is a prism, positioned above the actuator, according to one embodiment. [Figure 92] 1 illustrates a bimorph arm including an offset according to one embodiment. [Figure 93] 1 illustrates a bimorph arm including an offset and a limiter according to one embodiment. [Figure 94] 1 illustrates a bimorph arm including an offset and a limiter according to one embodiment. [Figure 95] 1 illustrates an embodiment of a base including a bimorph arm including an offset according to one embodiment. [Figure 96] 1 illustrates an embodiment of a base including two bimorph arms including an offset according to one embodiment. [Figure 97] 1 illustrates a buckler arm including a load point extension according to one embodiment. [Figure 98] A buckler arm 9801 is shown including a load point extension 9810 according to one embodiment. [Figure 99] 1 illustrates a bimorph arm including a load point extension according to one embodiment. [Figure 100] 1 illustrates a bimorph arm including a load point extension according to one embodiment. [Figure 101] 1 illustrates an SMA optical image stabilization mechanism according to one embodiment. [Figure 102] 4 shows an SMA material attachment portion 40 of the moving part according to one embodiment. [Figure 103] 13 illustrates a SAM mounting portion of a stationary plate with resistance welded SMA wires attached according to one embodiment. [Figure 104] 1 shows an SMA actuator 45 that includes a buckle actuator according to one embodiment. [Figure 105a] 1 illustrates a resistance weld crimp including islands for an SMA actuator according to one embodiment. [Figure 105b] 1 illustrates a resistance weld crimp including islands for an SMA actuator according to one embodiment. [Fig. 106] 13 illustrates the relationship between bending surface z offset, valley width, and peak force of a bimorph beam according to one embodiment. [Figure 107]13 shows an example of how box volume, an approximation of a box enclosing an entire bimorph actuator, relates to the work per bimorph component according to one embodiment. [Figure 108] 1 illustrates a liquid lens actuated using a buckler actuator according to one embodiment. [Figure 109] 13 illustrates an unanchored load point end of a bimorph arm according to one embodiment. [Figure 110] 13 illustrates an unanchored load point end of a bimorph arm according to one embodiment. [Figure 111] 13 illustrates an unanchored load point end of a bimorph arm according to one embodiment. [Figure 112] 13 illustrates an unanchored load point end of a bimorph arm according to one embodiment. [Figure 113] 1 illustrates a fixed end of a bimorph arm according to one embodiment. [Fig. 114] 1 illustrates a fixed end of a bimorph arm according to one embodiment. [Figure 115] 1 illustrates a fixed end of a bimorph arm according to one embodiment. [Fig. 116] 1 illustrates a fixed end of a bimorph arm according to one embodiment. [Figure 117] FIG. 13 illustrates a rear view of a fixed end of a bimorph arm according to one embodiment. [Figure 118] 13 illustrates an unanchored load point end of a bimorph arm according to one embodiment. [Figure 119] 13 shows a free load point end of a bimorph arm according to an alternative embodiment. [Figure 120] 13 shows a free load point end of a bimorph arm according to an alternative embodiment. [Figure 121] 13 shows a free load point end of a bimorph arm according to an alternative embodiment. [Figure 122] 13 shows a free load point end of a bimorph arm according to an alternative embodiment. [Figure 123] 1 illustrates a fixed end of a bimorph arm according to one embodiment. [Figure 124] 1 illustrates a fixed end of a bimorph arm according to one embodiment. [Fig. 125] 1 illustrates a fixed end of a bimorph arm according to one embodiment. [Fig. 126] 1 illustrates a balanced bimorph actuator including two bimorph arms arranged in staggered orientations according to one embodiment. [Figure 127] 1 illustrates optical image stabilization including a balanced bimorph actuator according to one embodiment. [Figure 128] 1 illustrates a balanced bimorph actuator including two bimorph arms arranged in a side-by-side orientation according to one embodiment. [Figure 129] FIG. 2 illustrates a top view of a balanced bimorph actuator according to one embodiment, including two bimorph arms arranged in a side-by-side orientation. [Fig. 130] FIG. 2 illustrates a top view of a balanced bimorph actuator according to an embodiment including a common base island. [Fig. 131] FIG. 2 illustrates a side view of a balanced bimorph actuator according to one embodiment, including two bimorph arms arranged in opposite, side-by-side orientation. [Fig. 132] FIG. 2 illustrates a top view of a balanced bimorph actuator according to one embodiment, including two bimorph arms arranged in opposite, side-by-side orientation. [Fig. 133] FIG. 2 illustrates a top view of a balanced bimorph actuator according to one embodiment, including two bimorph arms arranged in opposite, side-by-side orientation. [Fig. 134] 1 illustrates a balanced bimorph actuator including two bimorph arms arranged in a side-by-side orientation according to one embodiment. [Fig. 135] FIG. 2 illustrates a top view of a balanced bimorph actuator according to one embodiment, including two bimorph arms arranged in a side-by-side orientation. [Fig. 136] FIG. 2 illustrates a top view of a balanced bimorph actuator according to one embodiment, including two bimorph arms arranged in a side-by-side orientation. [Fig. 137] 1 illustrates a balanced bimorph actuator including two bimorph arms arranged in staggered orientations according to one embodiment. [Figure 138] FIG. 2 illustrates a top view of a balanced bimorph actuator according to one embodiment, including two bimorph arms arranged in staggered orientations. [Figure 139] FIG. 2 illustrates a top view of a balanced bimorph actuator according to one embodiment, including two bimorph arms arranged in staggered orientations. [Fig. 140] 1 illustrates an optical image stabilization system including a balanced bimorph actuator according to one embodiment. [Fig. 141] FIG. 2 illustrates an exploded view of an optical image stabilization system including a balanced bimorph actuator according to one embodiment. [Fig. 142] 1 illustrates an optical image stabilization system including a balanced bimorph actuator according to one embodiment. [Fig. 143] 1 illustrates a sensor-shifting optical image stabilization system including a bimorph actuator according to one embodiment. [Fig. 144] 1 illustrates an optical image stabilization system including a balanced bimorph actuator according to one embodiment. [Fig. 145] 1 illustrates an outer housing of an optical image stabilization system according to one embodiment. [Fig. 146] 1 illustrates a cross section of an optical image stabilization system including an outer housing according to one embodiment. [Fig. 147] 1 illustrates an exploded view of an optical image stabilization system including a leaf spring circuit according to one embodiment. [Fig. 148] 1 illustrates a cross-section of an optical image stabilization system including a leaf spring circuit according to one embodiment. [Figure 149] 1 illustrates a base including a spring according to one embodiment. [Fig. 150] 1 illustrates a leaf spring circuit according to one embodiment. [Fig. 151] 1 illustrates a bimorph actuator including a compression portion according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] Described herein are embodiments of SMA actuators that include a small footprint while providing a high actuation height, e.g., movement in the positive z-axis direction (z-direction), referred to herein as the z-stroke. SMA actuator embodiments include SMA buckle actuators and SMA bimorph actuators. SMA actuators can be used to mechanically collide two surfaces to provide a vibration sensation typically found in haptic feedback sensors and devices, and other systems in which actuators are used, in many applications including, but not limited to, lens assemblies as autofocus actuators, microfluidic pumps, sensor shifting, optical image stabilization, optical zoom assemblies, and other systems in which actuators are used. For example, actuator embodiments described herein can be used as haptic feedback actuators used in mobile phones or wearable devices configured to provide a user with an alert, notification, warning, touch area, or push button response. Additionally, two or more SMA actuators can be used to achieve a larger stroke in a system.

[0007] In various embodiments, the SMA actuator has a z-stroke greater than 0.4 millimeters. Additionally, the SMA actuator for various embodiments has a height in the z-direction of 2.2 millimeters or less when in its initial, parked position. Various embodiments of an SMA actuator configured as an autofocus actuator in a lens assembly can have a footprint as small as 3 millimeters greater than the lens inner diameter ("ID"). According to various embodiments, the SMA actuator can have a footprint that is wider in one direction than another to accommodate components including, but not limited to, sensors, wires, traces, and connectors. According to some embodiments, the footprint of the SMA actuator is 0.5 millimeters greater in one direction than another, e.g., the length of the SMA actuator is 0.5 millimeters greater than the width.

[0008] FIG. 1a illustrates a lens assembly including an SMA actuator configured as a buckle actuator, according to one embodiment. FIG. 1b illustrates an SMA actuator configured as a buckle actuator, according to one embodiment. Buckle actuators 102 are coupled to a base 101. As shown in FIG. 1b, the SMA wires 100 are attached to the buckle actuators 102 such that when the SMA wires 100 are actuated and contract, this causes the buckle actuators 102 to latch and at least a central portion 104 of each buckle actuator 102 to move in a z-stroke direction, e.g., in the positive z-direction, as shown by arrows 108. According to some embodiments, the SMA wires 100 are actuated when an electric current is supplied to one end of the wire that passes through a wire holder, such as a crimp structure 106. The electric current flows through the SMA wires 100 and heats the SMA wires 100 due to the inherent resistance in the SMA material from which the SMA wires 100 are made. The other side of the SMA wire 100 has a wire holder, such as a crimp structure 106, that connects the SMA wire 100 to complete the circuit to ground. Heating the SMA wire 100 to a sufficient temperature changes the unique material properties from a martensite crystal structure to an austenite crystal structure, thereby changing the length of the wire. Changing the current changes the temperature of the wire, and therefore the length of the wire, which is used to activate and deactivate the actuator to control the movement of the actuator in at least the z-direction. Those skilled in the art will appreciate that other techniques can be used to provide current to the SMA wire.

[0009] Figure 2 illustrates an SMA actuator configured as an SMA bimorph actuator according to one embodiment. As shown in Figure 2, the SMA actuator includes a bimorph actuator 202 coupled to a base 204. The bimorph actuator 202 includes an SMA ribbon 206. The bimorph actuator 202 is configured to move at least an unanchored end of the bimorph actuator 202 in a z-stroke direction 208 when the SMA ribbon 206 contracts.

[0010] FIG. 3 illustrates an exploded view of an autofocus assembly including an SMA actuator according to one embodiment. As shown, the SMA actuator 302 is configured as a buckle actuator according to embodiments described herein. The autofocus assembly also includes an optical image stabilization ("OIS") 304, a lens carriage 306 configured to hold one or more optical lenses using techniques including those known in the art, a return spring 308, a vertical plain bearing 310, and a guide cover 312. The lens carriage 306 is configured such that the SMA wire is actuated and pulled using techniques including those described herein to buckle the buckle actuator 302, and slides against the vertical plain bearing 310 as the SMA actuator 302 moves in a z-stroke direction, e.g., the positive z-direction. The return spring 308 is configured to exert a force on the lens carriage 306 in a direction opposite to the z-stroke direction, using techniques including those known in the art. The return spring 308 is configured, according to various embodiments, to move the lens carriage 306 in the opposite direction of the z-stroke direction when the tension in the SMA wire decreases as the SMA wire comes to rest. When the tension in the SMA wire decreases to an initial value, the lens carriage 306 moves to a minimum height in the z-stroke direction. Figure 4 illustrates an autofocus assembly including an SMA actuator according to one embodiment shown in Figure 3.

[0011] FIG. 5 illustrates an SMA wire actuator according to one embodiment that includes a sensor. In various embodiments, the sensor 502 is configured to measure the movement of the SMA actuator in the z-direction or the movement of a component that the SMA actuator is moving using techniques including those known in the art. The SMA actuator includes one or more buckle actuators 506 configured for actuation using one or more SMA wires 508 similar to those described herein. For example, in the autofocus assembly described with reference to FIG. 4, the sensor is configured to determine the amount of movement that the lens carriage 306 moves in the z-direction 504 from an initial position using techniques including those known in the art. According to some embodiments, the sensor is a tunneling magnetoresistance ("TMR") sensor.

[0012] FIG. 6 illustrates a top view and a side view of an SMA actuator 602 configured as a buckle actuator according to one embodiment with a lens carriage 604 attached. FIG. 7 illustrates a side view of a section of the SMA actuator 602 according to the embodiment illustrated in FIG. 6. According to the embodiment illustrated in FIG. 7, the SMA actuator 602 includes a slide base 702. According to one embodiment, the slide base 702 is formed from a metal, such as stainless steel, using techniques including those known in the art. However, one of ordinary skill in the art will appreciate that other materials may be used to form the slide base 702. Additionally, the slide base 702 according to some embodiments has a spring arm 612 coupled to the SMA actuator 602. According to various embodiments, the spring arm 612 is configured to provide two functions. The first function is to help push an object, such as the lens carriage 604, into the vertical slide surface of the guide cover. In this example, the spring arm 612 preloads the lens carriage 604 against this surface to ensure that the lens does not tilt during actuation. In some embodiments, the vertical slide surface 708 is configured to mate with a guide cover. A second function of the spring arm 612 is to help pull the SMA actuator 602 back downwards, e.g., in the negative z direction, after the SMA wire 608 has moved the SMA actuator 602 in the z-stroke direction, i.e., in the positive z direction. Thus, when actuated, the SMA wire 608 contracts to move the SMA actuator 602 in the z-stroke direction, and the spring arm 612 is configured to move the SMA actuator 602 in the opposite direction to the z-stroke direction when the SMA wire 608 is stopped.

[0013] The SMA actuator 602 also includes a buckle actuator 710. In various embodiments, the buckle actuator 710 is formed from a metal, such as stainless steel. The buckle actuator 710 further includes a buckle arm 610 and one or more wire retainers 606. According to the embodiment shown in FIGS. 6 and 7, the buckle actuator 710 includes four wire retainers 606. Each of the four wire retainers 606 is configured to receive an end of an SMA wire 608 and hold the SMA wire 608 such that the SMA wire 608 is attached to the buckle actuator 710. In various embodiments, the four wire retainers 606 are crimps that are configured to clamp a portion of the SMA wire 608 to attach the wire to the crimp. One skilled in the art will appreciate that the SMA wire 608 can be attached to the wire retainers 606 using techniques known in the art, including, but not limited to, adhesives, solder, and mechanical attachment. A smart memory alloy ("SMA") wire 608 extends between the pair of wire retainers 606, and the buckle arms 610 of the buckle actuator 710 are configured to move when the SMA wire 608 is actuated, thereby pulling the pair of wire retainers 606 toward each other. According to various embodiments, the SMA wire 608 is electrically actuated to move and control the position of the buckle arms 610 when a current is applied to the SMA wire 608. The SMA wire 608 stops when the current is removed or below a threshold. This causes the pair of wire retainers 606 to move apart, and the buckle arms 610 to move in a direction opposite to the direction in which the SMA wire 608 was actuated. According to various embodiments, the buckle arms 610 are configured to have an initial angle of 5 degrees with respect to the slide base 702 when the SMA wire is resting in its initial position. Also, at full stroke, or when the SMA wire is fully actuated, the buckle arm 610 is configured to have an angle of 10-12 degrees relative to the sliding base 702 according to various embodiments.

[0014] According to the embodiment shown in Figures 6 and 7, the SMA actuator 602 also includes a sliding bearing 706 configured between the slide base 702 and the wire holder 606. The sliding bearing 706 is configured to minimize any friction between the slide base 702 and the buckle arms 610 and / or wire holder 606. The sliding bearing in some embodiments is attached to the wire holder 606. According to various embodiments, the sliding bearing is formed from polyoxymethylene ("POM"). One skilled in the art will appreciate that other structures can be used to reduce any friction between the buckle actuator and the base.

[0015] According to various embodiments, the slide base 702 is configured to mate with an assembly base 704, such as an autofocus base for an autofocus assembly. The actuator base 704, according to some embodiments, includes an etched shim. Such an etched shim can be used to provide clearance for wires and crimps when the SMA actuator 602 is part of an assembly, such as an autofocus assembly.

[0016] FIG. 8 shows multiple views of one embodiment of a buckle actuator 802 relative to the x, y, and z axes. As oriented in FIG. 8, the buckle arms 804 are configured to move in the z axis when the SMA wires are actuated and deactuated as described herein. According to the embodiment shown in FIG. 8, the buckle arms 804 are coupled together via a central portion, such as a hammock portion 806. The hammock portion 806, according to various embodiments, is configured to carry an object that the buckle actuator acts upon, for example, a portion of a lens carriage that the buckle actuator moves using techniques including those described herein. The hammock portion 806, according to some embodiments, is configured to provide lateral stiffness to the buckle actuator during actuation. In other embodiments, the buckle actuator does not include a hammock portion 806. According to these embodiments, the buckle arms are configured to act on an object to move the object. For example, the buckle arms are configured to act directly on a mechanism of the lens carriage to push the lens carriage up.

[0017] FIG. 9 illustrates an SMA actuator configured as an SMA bimorph actuator according to one embodiment. The SMA bimorph actuator includes bimorph actuators 902, including those described herein. According to the embodiment illustrated in FIG. 9, one end 906 of each of the bimorph actuators 902 is attached to a base 908. According to some embodiments, the one end 906 is welded to the base 908. However, one of ordinary skill in the art will appreciate that other techniques can be used to attach the one end 906 to the base 908. FIG. 9 also illustrates a lens carriage 904 arranged such that the bimorph actuators 902 are configured to curl up in the z-direction when actuated, lifting the carriage 904 in the z-direction. In some embodiments, a return spring is used to push the bimorph actuators 902 back to their initial position. The return spring can be configured to help push the bimorph actuators down to their initial, rest position, as described herein. The small footprint of bimorph actuators allows the creation of SMA actuators with reduced footprints compared to current actuator technologies.

[0018] 10 shows a cutaway view of an autofocus assembly including an SMA actuator according to one embodiment, including a position sensor such as a TMR sensor. The autofocus assembly 1002 includes a position sensor 1004 attached to a movable spring 1006 and a magnet 1008 attached to a lens carriage 1010 of the autofocus assembly including an SMA actuator, such as those described herein. The position sensor 1004 is configured to determine the amount of movement that the lens carriage 1010 moves in the z-direction 1005 from an initial position based on the distance of the magnet 1008 from the position sensor 1004, using techniques including those known in the art. According to some embodiments, the position sensor 1004 is electrically coupled to a controller or processor, such as a central processing unit, using a number of electrical traces on the spring arm of the movable spring 1006 of the optical image stabilization assembly.

[0019] 11a-11c show diagrams of a bimorph actuator according to some embodiments. According to various embodiments, the bimorph actuator 1102 includes a beam 1104 and one or more SMA materials 1106, such as SMA ribbon 1106b (e.g., as shown in a perspective view of a bimorph actuator including an SMA ribbon according to an embodiment of FIG. 11b) or SMA wire 1106a (e.g., as shown in a cross-section of a bimorph actuator including an SMA wire according to an embodiment of FIG. 11a). The SMA material 1106 is attached to the beam 1104 using techniques including those described herein. According to some embodiments, the SMA material 1106 is attached to the beam 1104 using an adhesive film material 1108. In various embodiments, ends of the SMA material 1106 are electrically and mechanically coupled to contacts 1110 configured to provide electrical current to the SMA material 1106 using techniques including those known in the art. The contacts 1110 according to various embodiments (e.g., as shown in Figures 11a and 11b) are gold plated copper pads. According to embodiments, a bimorph actuator 1102 having a length of approximately 1 millimeter is configured to generate a large stroke, e.g., a pressing force of 50 milliNewtons ("mN"), as shown in Figure 11c, is used as part of a lens assembly. According to some embodiments, the use of a bimorph actuator 1102 having a length greater than 1 millimeter generates a larger stroke but a smaller force than a bimorph actuator having a length of 1 millimeter. In one embodiment, the bimorph actuator 1102 includes a 20 micrometer thick SMA material 1106, a 20 micrometer thick insulator 1112, such as a polyimide insulator, and a 30 micrometer thick stainless steel beam 1104 or base metal. Various embodiments include a second insulator disposed between the contact layer including the contacts 1110 and the SMA material 1106. The second insulator is configured to insulate the SMA material 1106 from portions of the contact layer that are not used as contacts 1110, according to some embodiments.In some embodiments, the second insulator is a covercoat layer, such as a polyimide insulator. Those skilled in the art will appreciate that other dimensions and materials can be used to meet desired design characteristics.

[0020] FIG. 12 shows a diagram of an embodiment of a bimorph actuator according to an embodiment. The embodiment shown in FIG. 12 includes a central feed 1204 that applies power. Power is supplied to the center of the SMA material 1202 (wire or ribbon), such as those described herein. The ends of the SMA material 1202 are grounded to a beam 1206 or base metal as a return at end pads 1203. The end pads 1203 are electrically isolated from the remainder of the contact layer 1214. According to an embodiment, the proximity of the beam 1206 or base metal to the SMA material 1202, such as an SMA wire, along its entire length allows the wire to cool faster when the current is turned off, i.e., the bimorph actuator is stopped. This results in faster wire deactivation and actuator response times. The thermal profile of the SMA wire or ribbon is improved. For example, the thermal profile is more uniform to ensure a higher total current can be delivered to the wire. Without a uniform heat sink, portions of the wire, such as the center region, can become overheated and damaged, and therefore require reduced current and reduced motion to operate reliably. The center feed 1204 provides the benefits of faster wire activation / actuation (faster heating) and reduced power consumption of the SMA material 1202 for faster response time (reduced resistive path length). This allows for faster actuator movement and the ability to operate at higher movement frequencies.

[0021] 12, the beam 1206 includes a central metal 1208 that is insulated from the remainder of the beam 1206 to form a central feed 1204. An insulator 1210, such as those described herein, is disposed on top of the beam 1206. The insulator 1210 is configured with one or more openings or vias 1212 to provide electrical access to the beam 1206, for example, to couple the ground section 1214b of the contact layer, and to provide contacts to the central metal 1208 to form the central feed 1204. The contact layer 1214, such as those described herein, includes a power section 1214a and a ground section 1214b according to some embodiments that provide actuation / control signals to the bimorph actuator via a power contact 1216 and a ground contact 1218. A covercoat layer 1220, such as that described herein, is disposed over the contact layer 1214 to electrically isolate the contact layer except for portions of the contact layer 1214 to which electrical coupling is desired (e.g., one or more contacts).

[0022] FIG. 13 illustrates an end pad cross section of a bimorph actuator according to one embodiment as shown in FIG. 12. As described above, the end pad 1203 is electrically isolated from the remainder of the contact layer 1214 by a gap 1222 formed between the end pad 1203 and the contact layer 1214. The gap is formed using etching techniques, including those known in the art, according to some embodiments. The end pad 1203 includes a via section 1224 configured to electrically couple the end pad 1203 to the beam 1206. The via section 1224 is formed in a via 1212 formed in the insulator 1210. The SMA material 1202 is electrically coupled to the end pad 1203. The SMA material 1202 can be electrically coupled to the end pad 1203 using techniques including, but not limited to, soldering, resistance welding, laser welding, and direct plating.

[0023] Figure 14 shows a cross section of a central feed of a bimorph actuator according to one embodiment as shown in Figure 12. The central feed 1204 is electrically coupled to a power source through a contact layer 1214 and is electrically and thermally coupled to the central metal 1208 by a via section 1224 of the central feed 1204 formed in a via 1212 formed in the insulator 1210.

[0024] The actuators described herein can be used to form actuator assemblies using multiple buckle actuators and / or bimorph actuators. According to one embodiment, the actuators can be stacked on top of each other to increase the stroke distance that can be achieved.

[0025] 15 shows an exploded view of an SMA actuator including two buckle actuators according to one embodiment. The two buckle actuators 1302, 1304 according to embodiments described herein are positioned relative to one another to use their counteracting motions. In various embodiments, the two buckle actuators 1302, 1304 are configured to move in an inverse relationship to one another to position the lens carriage 1306. For example, the first buckle actuator 1302 is configured to receive an inverse power signal of a power signal sent to the second buckle actuator 1304.

[0026] 16 illustrates an SMA actuator including two buckle actuators according to one embodiment. The buckle actuators 1302, 1304 are configured such that the buckle arms 1310, 1312 of each buckle actuator 1302, 1304 face each other and the sliding bases 1314, 1316 of each buckle actuator 1302, 1304 are exterior surfaces of the two buckle actuators. A hammock portion 1308 of each SMA actuator 1302, 1304 according to various embodiments is configured to carry an object that one or more buckle actuators 1302, 1304 act on, such as a portion of a lens carriage 1306 that the buckle actuators move using techniques including those described above.

[0027] FIG. 17 shows a side view of an SMA actuator including two buckle actuators according to one embodiment showing the orientation of the SMA wires 1318 that effect movement of an object such as a lens carriage in the positive z-direction, or upward direction.

[0028] FIG. 18 shows a side view of an SMA actuator including two buckle actuators according to one embodiment showing the orientation of the SMA wires 1318 that effect movement of an object such as a lens carriage in the negative z-direction, or downward direction.

[0029] 19 shows an exploded view of an assembly including an SMA actuator including two buckle actuators according to one embodiment. The buckle actuators 1902, 1904 are configured such that the buckle arms 1910, 1912 of each buckle actuator 1902, 1904 are the outer surfaces of the two buckle actuators, and the sliding bases 1914, 1916 of each buckle actuator 1902, 1904 face each other. According to various embodiments, the hammock portion 1908 of each SMA actuator 1902, 1904 is configured to carry an object that one or more buckle actuators 1902, 1904 act on, such as a portion of a lens carriage 1906 that the buckle actuators move using techniques including those described herein. In some embodiments, the SMA actuator includes a base portion 1918 configured to receive the second buckle actuator 1904. The SMA actuator can also include a cover portion 1920. FIG. 20 illustrates an SMA actuator including two buckle actuators according to one embodiment including a base portion and a cover portion.

[0030] 21 illustrates an SMA actuator including two buckle actuators according to one embodiment. In some embodiments, the buckle actuators 1902, 1904 are positioned relative to one another such that the hammock portion 1908 of the first buckle actuator 1902 is rotated approximately 90 degrees from the hammock portion of the second buckle actuator 1904. The 90 degree configuration allows for pitch and roll rotation of an object such as the lens carriage 1906. This allows for better control of the movement of the lens carriage 1906. In various embodiments, a differential power signal is applied to the SMA wires of each buckle actuator pair, which allows for pitch and roll rotation of the lens carriage for tilting OIS movements.

[0031] An embodiment of an SMA actuator that includes two buckle actuators eliminates the need to have a return spring. The use of two buckle actuators can improve / reduce hysteresis when using SMA wire resistance for position feedback. Opposing force SMA actuators that include two buckle actuators have less hysteresis than those that include return springs, which lends to more precise position control. In some embodiments, such as the embodiment shown in FIG. 22, an SMA actuator that includes two buckle actuators 2202, 2204 provides two-axis tilt using differential power to the left SMA wire 2218a and the right SMA wire 2218b of each buckle actuator 2202, 2204. For example, the left SMA wire 2218a is actuated with higher power than the right SMA wire 2218b. This causes the left side of the lens carriage 2206 to move downwards and the right side to move (tilt) upwards. The SMA wires of the first buckle actuator 2202, in some embodiments, are held at equal power to act as a fulcrum that pushes differentially against the SMA wires 2218a, 2218b to provide tilting motion. For example, applying equal power to the SMA wires of the second buckle actuator 2204 and using differential power to the left SMA 2218a and right SMA 2218b of the second buckle actuator 2204 and reversing the power signal applied to the SMA wires will cause the lens carriage 2206 to tilt in the other direction. This allows an object such as a lens carrier to be tilted in either axis of motion, or can be adjusted to eliminate any tilt between the lens and the sensor for better dynamic tilt, resulting in better image quality across all pixels.

[0032] 23 illustrates an SMA actuator including two buckle actuators and a coupler according to one embodiment. The SMA actuator includes two buckle actuators such as those described herein. A first buckle actuator 2302 is configured to couple with a second buckle actuator 2304 using a coupler such as a coupler ring 2305. The buckle actuators 2302, 2304 are positioned relative to one another such that a hammock portion 2308 of the first buckle actuator 2302 is rotated approximately 90 degrees from a hammock portion 2309 of the second buckle actuator 2304. A payload to be moved, such as a lens or lens assembly, is attached to a lens carriage 2306 configured to be placed on a sliding base of the first buckle actuator 2302.

[0033] In various embodiments, equal power can be applied to the SMA wires of the first buckle actuator 2302 and the second buckle actuator 2304. This can maximize the z-stroke of the SMA actuator in the positive z-direction. In some embodiments, the stroke of the SMA actuator can have a z-stroke that is more than twice as long as the stroke of the other SMA actuator, including the two buckle actuators. In some embodiments, an additional spring can be added to push against the two buckle actuators to help push the actuator assembly and payload back down when the power signal is removed from the SMA actuator. Equal and opposite power signals can be applied to the SMA wires of the first buckle actuator 2302 and the second buckle actuator 2304. This can cause the SMA actuator to move in the positive z-direction with one buckle actuator and in the negative z-direction with one buckle actuator, allowing precise control of the position of the SMA actuator. Additionally, equal and opposite power signals (differential power signals) can be applied to the left and right SMA wires of the first buckle actuator 2302 and the second buckle actuator 2304 to tilt an object such as the lens carriage 2306 in at least one of two axes.

[0034] An embodiment of an SMA actuator including two buckle actuators and a coupler, such as that shown in FIG. 23, can be coupled to additional buckle actuators and pairs of buckle actuators to achieve a desired stroke greater than the stroke of a single SMA actuator.

[0035] FIG. 24 shows an exploded view of an SMA system including an SMA actuator including a buckle actuator with a laminate hammock, according to one embodiment. As described herein, the SMA system is configured in some embodiments to be used with one or more camera lens elements as an autofocus drive mechanism. As shown in FIG. 24, the SMA system includes a return spring 2403 configured to move the lens carriage 2405 in the opposite direction to the z-stroke direction when tension in the SMA wire 2408 is reduced as the SMA wire 2408 stops, according to various embodiments. The SMA system of some embodiments includes a housing 2409 configured to receive the return spring 2403 and act as a sliding bearing to guide the lens carriage in the z-stroke direction. The housing 2409 is also configured to be disposed over the buckle actuator 2402. The buckle actuator 2402 includes a slide base 2401 similar to that described herein. The buckle actuator 2402 includes a buckle arm 2404 coupled to a hammock portion, such as a laminate hammock 2406, formed from a laminate. The buckle actuator 2402 also includes an SMA wire attachment structure, such as a laminate molded crimp connection 2412.

[0036] As shown in Figure 24, the sliding base 2401 is placed on an optional adapter plate 2414. The adapter plate is configured to mate the SMA system or buckle actuator 2402 to another system, such as an OIS, an additional SMA system, or other component. Figure 25 shows an SMA system 2501 including an SMA actuator that includes a buckle actuator 2402 with a laminate hammock, according to one embodiment.

[0037] FIG. 26 illustrates a buckle actuator including a laminate hammock according to one embodiment. The buckle actuator 2402 includes a buckle arm 2404. The buckle arm 2404 is configured to move in the z-axis when an SMA wire 2408 is actuated and deactuated as described herein. The SMA wire 2408 is attached to the buckle actuator using a laminate molded crimp connection 2412. According to the embodiment shown in FIG. 26, the buckle arms 2404 are coupled together through a central portion such as a laminate hammock 2406. The laminate hammock 2406 according to various embodiments is configured to carry an object that the buckle actuator acts on, such as a portion of a lens carriage that the buckle actuator moves using techniques including those described herein.

[0038] FIG. 27 illustrates a laminate hammock for an SMA actuator according to one embodiment. In some embodiments, the material of the laminate hammock 2406 is a low stiffness material and therefore does not resist actuation motion. For example, the laminate hammock 2406 is formed using a copper layer disposed on a first polyimide layer with a second polyimide layer disposed on the copper layer. In some embodiments, the laminate hammock 2406 is formed on the buckle arm 2404 using deposition and etching techniques including those known in the art. In other embodiments, the laminate hammock 2406 is formed separately from the buckle arm 2404 and attached to the buckle arm 2404 using techniques including welding, adhesives, and other techniques known in the art. In various embodiments, glue or other adhesives are used on the laminate hammock 2406 to ensure that the buckle arm 2404 remains in place relative to the lens carriage.

[0039] 28 illustrates a laminate molded crimp connection for an SMA actuator according to one embodiment. The laminate molded crimp connection 2412 is configured to attach the SMA wire 2408 to the buckle actuator and form an electrical circuit junction with the SMA wire 2408. In various embodiments, the laminate molded crimp connection 2412 includes a laminate formed from one or more layers of insulation and one or more layers of conductive layers formed over the crimp.

[0040] For example, a polyimide layer is disposed over at least a portion of the stainless steel portion forming the crimp 2413. A conductive layer, such as copper, is then disposed over the polyimide layer, which is electrically coupled to one or more signal traces 2415 disposed over the buckle actuator. Deforming the crimp to contact the SMA wire therein also causes the SMA wire to electrically contact the conductive layer. Thus, the conductive layer coupled to the signal trace or traces is used to apply a power signal to the SMA wire using techniques including those described herein. In some embodiments, a second polyimide layer is formed over the conductive layer in areas where the conductive layer does not contact the SMA wire. In some embodiments, the laminate molded crimp connection 2412 is formed over the crimp 2413 using deposition and etching techniques including those known in the art. In other embodiments, the laminate molded crimp connection 2412 and one or more electrical traces are formed separately from the crimp portion 2413 and the buckle actuator and attached to the crimp portion 2413 and the buckle actuator using techniques including welding, adhesives, and other techniques known in the art.

[0041] Figure 29 shows an SMA actuator including a buckle actuator with a laminate hammock. As shown in Figure 29, when a power signal is applied, the SMA wire contracts or shortens, causing the buckle arms and laminate hammock to move in the positive z direction. The laminate hammock in contact with an object thereby moves the object, such as a lens carriage, in the positive z direction. When the power signal is reduced or removed, the SMA wire expands, causing the buckle arms and laminate hammock to move in the negative z direction.

[0042] FIG. 30 shows an exploded view of an SMA system including an SMA actuator, including a buckle actuator, according to one embodiment. As described herein, the SMA system, in some embodiments, is configured to be used with one or more camera lens elements as an autofocus drive mechanism. As shown in FIG. 30, the SMA system, in various embodiments, includes a return spring 3003 configured to move the lens carriage 3006 in a direction opposite to the z-stroke direction when tension in the SMA wire 3008 is reduced as the SMA wire stops. The SMA system, in some embodiments, includes a stiffener 3000 disposed on the return spring 3003. The SMA system, in some embodiments, includes a two-part housing 3009 configured to receive the return spring 3003 and act as a sliding bearing to guide the lens carriage in the z-stroke direction. The housing 3009 is also configured to be disposed over the buckle actuator 3002. The buckle actuator 3002 includes a two-part slide base 3001 similar to that described herein. The slide base 3001, according to some embodiments, is split to electrically isolate the two sides (e.g., one side is ground and the other side is power) as current flows through portions of the slide base 3001 to the wires.

[0043] The buckle actuator 3002 includes buckle arms 3004. Each pair of the buckle actuators 3002 is formed in a separate portion of the buckle actuator 3002. The buckle actuator 3002 also includes an SMA wire attachment structure, such as a resistance weld wire crimp 3012. The SMA system optionally includes a flex circuit 3020 that electrically couples the SMA wire 3008 to one or more control circuits.

[0044] As shown in Figure 30, the sliding base 3001 is placed on an optional adapter plate 3014. The adapter plate is configured to mate the SMA system or buckle actuator 3002 to another system, such as an OIS, additional SMA systems, or other components. Figure 31 shows an SMA system 3101 including an SMA actuator that includes a buckle actuator 3002, according to one embodiment.

[0045] Figure 32 illustrates an SMA actuator that includes a buckle actuator according to one embodiment. The buckle actuator 3002 includes a buckle arm 3004. The buckle arm 3004 is configured to move in the z-axis when an SMA wire 3008 is actuated and deactuated as described above. The SMA wire 3008 is attached to a resistance weld wire crimp 3012. According to the embodiment illustrated in Figure 32, the buckle arm 3004 is configured to mate with an object, such as a lens carriage, without a center section using a two yoke capture joint.

[0046] FIG. 33 shows a two yoke capture junction of a pair of buckle arms of an SMA actuator according to one embodiment. FIG. 33 also shows plating pads 3022 used to attach an optional flex circuit to the sliding base. In some embodiments, the plating pads 3022 are formed using gold. FIG. 34 shows a resistance weld crimp for an SMA actuator according to one embodiment used to attach the SMA wire to the buckle actuator. In some embodiments, glue or adhesive can also be placed on top of the welds to help with mechanical strength and act as a fatigue strain relief during operation and shock loading.

[0047] FIG. 35 shows an SMA actuator that includes a buckle actuator with two yoke capture joints. As shown in FIG. 35, when a power signal is applied, the SMA wire contracts or shortens, moving the buckle arm in the positive z direction. The two yoke capture joints contact an object, which then moves the object, such as a lens carriage, in the positive z direction. When the power signal is reduced or removed, the SMA wire expands, moving the buckle arm in the negative z direction. The yoke capture mechanism ensures that the buckle arm remains in the correct position relative to the lens carriage.

[0048] FIG. 36 illustrates an SMA bimorph liquid lens according to one embodiment. The SMA bimorph liquid lens 3501 includes a liquid lens subassembly 3502, a housing 3504, and a circuit 3506 with an SMA actuator. In various embodiments, the SMA actuator includes four bimorph actuators 3508, such as the embodiments described herein. The bimorph actuators 3508 are configured to press a shaped ring 3510 located on top of a flexible membrane 3512. The ring distorts the membrane 3512 / liquid 3514 to change the optical path through the membrane 3512 / liquid 3514. A liquid containment ring 3516 is used to contain the liquid 3514 between the membrane 3512 and the lens 3518. Equal forces from the bimorph actuators change the focus of the image in the Z direction (perpendicular to the lens), allowing the SMA bimorph liquid lens 3501 to function as an autofocus. Differential forces from the bimorph actuators 3508 can move the light beam in the X and Y directions, allowing the SMA bimorph liquid lens 3501 to act as an optical image stabilization mechanism according to some embodiments. Both OIS and AF functions can be achieved simultaneously with appropriate control for each actuator. In some embodiments, three actuators are used. The circuit with SMA actuators 3506 includes one or more contacts 3520 for control signals that activate the SMA actuators. According to some embodiments including four SMA actuators, the circuit with SMA actuators 3506 includes four power circuit control contacts for each SMA actuator and a common return contact.

[0049] Figure 37 shows an SMA bimorph liquid lens viewed from an oblique top view according to one embodiment. Figure 38 shows a cross-sectional and bottom view of an SMA bimorph liquid lens according to one embodiment. FIG. 39 illustrates an SMA system including an SMA actuator 3902 with bimorph actuators according to one embodiment. The SMA actuator 3902 includes four bimorph actuators using the techniques described herein. As shown in FIG. 40, which illustrates an SMA actuator 3902 with bimorph actuators according to one embodiment, two of the bimorph actuators are configured as positive z-stroke actuators 3904 and two are configured as negative z-stroke actuators 3906. The opposing actuators 3906, 3904 are configured to control motion in both directions throughout the stroke range. This allows the control code to be adjusted to compensate for tilt. In various embodiments, two SMA wires 3908 attached to the top of the component allow positive z-stroke displacement. Two SMA wires attached to the bottom of the component allow negative z-stroke displacement. In some embodiments, each bimorph actuator is attached to an object, such as a lens carriage 3910, using tabs that engage the object. The SMA system includes a top spring 3912 configured to provide stability to the lens carriage 3910 in an axis perpendicular to the z-stroke axis, e.g., in the x- and y-axis directions. Additionally, a top spacer 3914 is configured to be disposed between the top spring 3912 and the SMA actuator 3902. A bottom spacer 3916 is disposed between the SMA actuator 3902 and a bottom spring 3918. The bottom spring 3918 is configured to provide stability to the lens carriage 3910 in an axis perpendicular to the z-stroke axis, e.g., in the x- and y-axis directions. The bottom spring 3918 is configured to be disposed on a base 3920, such as those described herein.

[0050] 41 shows the length 4102 of the bimorph actuator 4103 and the location of the bond pads 4104 where the SMA wire 4106 extends the wire length beyond the bimorph actuator. A longer wire is used than the bimorph actuator to increase the stroke and force. Thus, the extension length 4108 of the SMA wire 4106 beyond the bimorph actuator 4103 is used to set the stroke and force for the bimorph actuator 4103.

[0051] FIG. 42 shows an exploded view of an SMA system including an SMA bimorph actuator 4202 according to one embodiment. SMA systems according to various embodiments are configured to use separate metal materials and non-conductive adhesives to create one or more electrical circuits that independently power the SMA wires. Some embodiments do not affect the AF size and include four bimorph actuators such as those described herein. Two of the bimorph actuators are configured as positive z-stroke actuators and two are configured as negative z-stroke actuators. FIG. 43 shows an exploded view of a subsection of an SMA actuator according to one embodiment. The subsection includes a base 4304 with a negative actuator signal connection 4302, a bimorph actuator 4306. The negative actuator signal connection 4302 includes a wire bond pad 4308 for connecting the SMA wires of the bimorph actuator 4306 using techniques including those described herein. The negative actuator signal connection 4302 is attached to the base 4304 using an adhesive layer 4310. The subsection also includes a positive actuator signal connection 4314 with a wire bond pad 4316 for connecting the SMA wire 4312 of the bimorph actuator 4306 using techniques including those described herein. The positive actuator signal connection 4314 is attached to the base 4304 using an adhesive layer 4318. Each of the base 4304, the negative actuator signal connection 4302, and the positive actuator signal connection 4314 are formed from a metal, for example stainless steel. The connection pads 4322 on each of the base 4304, the negative actuator signal connection 4302, and the positive actuator signal connection 4314 are configured to electrically couple control signals and ground to actuate the bimorph actuator 4306 using techniques including those described herein. In some embodiments, the connection pads 4322 are gold plated. FIG. 44 illustrates a subsection of an SMA actuator according to one embodiment. In some embodiments, gold plated pads are formed on the stainless steel layer for solder bonding or other known electrical termination methods.Additionally, molded wire bond pads are used for the signal junctions to electrically couple SMA wires for power signals.

[0052] FIG. 45 illustrates a 5-axis sensor shift system according to an embodiment. The 5-axis sensor shift system is configured to move an object, such as an image sensor, in 5 axes relative to one or more lenses. This includes X / Y / Z axis translation and pitch / roll tilt. Optionally, the system is configured to use only 4 axes, including X / Y axis translation and pitch / roll tilt, with a separate AF on top to perform Z motion. Other embodiments include a 5-axis sensor shift system configured to move one or more lenses relative to an image sensor. In some embodiments, a static lens stack is mounted on top of the top cover and inserted inside the ID (without touching the orange moving carriage inside).

[0053] FIG. 46 shows an exploded view of a five-axis sensor shifting system according to one embodiment. The five-axis sensor shifting system includes two circuit components: a flexible sensor circuit 4602, a bimorph actuator circuit 4604, and 8-12 bimorph actuators 4606 built into the bimorph circuit components using techniques including those described herein. The five-axis sensor shifting system includes a moveable carriage 4608 configured to hold one or more lenses, and an outer housing 4610. The bimorph actuator circuit 4604 includes 8-12 SMA actuators such as those described herein according to one embodiment. The SMA actuators are configured to move the moveable carriage 4608 in five axes, such as x-direction, y-direction, z-direction, pitch and roll similar to other five-axis systems described herein.

[0054] FIG. 47 shows an SMA actuator according to one embodiment, including a bimorph actuator integrated into the circuit for all motions. An embodiment of the SMA actuator may include 8-12 bimorph actuators 4606. However, other embodiments may include more or fewer bimorph actuators. FIG. 48 shows an SMA actuator 4802 according to one embodiment, including a bimorph actuator integrated into the circuit for all motions, partially formed to fit inside a corresponding outer housing 4804. FIG. 49 shows a cross section of a 5-axis sensor shifting system according to one embodiment.

[0055] Figure 50 shows an SMA actuator 5002 according to one embodiment including a bimorph actuator. The SMA actuator 5002 is configured to move an image sensor, lens or other various payloads in the x and y directions using four side mounted SMA bimorph actuators 5004. Figure 51 shows a top view of an SMA actuator including a bimorph actuator moving an image sensor, lens or other various payloads at different x and y positions.

[0056] FIG. 52 illustrates an SMA actuator including a bimorph actuator 5202 according to an embodiment configured as a box bimorph autofocus. Four top and bottom mounted SMA bimorph actuators, such as those described herein, are configured to move together to provide movement in the z-stroke direction for autofocus movement. FIG. 53 illustrates an SMA actuator including a bimorph actuator according to an embodiment, where two top mounted bimorph actuators 5302 are configured to push one or more lenses down. FIG. 54 illustrates an SMA actuator including a bimorph actuator according to an embodiment, where two bottom mounted bimorph actuators 5402 are configured to push one or more lenses up. FIG. 55 illustrates an SMA actuator including a bimorph actuator according to an embodiment showing four top and bottom mounted SMA bimorph actuators 5502, such as those described herein, being used to move one or more lenses to provide tilting movement.

[0057] FIG. 56 shows an SMA system including an SMA actuator according to an embodiment, including a bimorph actuator configured as a two-axis lens shift OIS. In some embodiments, the two-axis lens shift OIS is configured to move the lens in the X / Y axis. In some embodiments, the Z-axis motion comes from a separate AF, such as those described herein. The four bimorph actuators push the sides of the autofocus for OIS motion. FIG. 57 shows an exploded view of an SMA system including an SMA actuator 5802 according to an embodiment, including a bimorph actuator 5806 configured as a two-axis lens shift OIS. FIG. 58 shows a cross section of an SMA system including an SMA actuator 5802 according to an embodiment, including a bimorph actuator 5806 configured as a two-axis lens shift OIS. FIG. 59 shows a box bimorph actuator 5802 according to an embodiment, configured as a two-axis lens shift OIS as manufactured before being molded to fit the system, for use in an SMA system. Such a system can be configured to have a high OIS stroke OIS (e.g., ±200 μm or more). Additionally, such embodiments are configured to have a wide range of motion and excellent OIS dynamic tilt using four plain bearings, such as POM plain bearings. These embodiments are configured to easily integrate with AF designs (e.g., VCM or SMA).

[0058] FIG. 60 illustrates an SMA system including an SMA actuator according to an embodiment including a bimorph actuator configured as a 5-axis lens shift OIS and autofocus. In some embodiments, the 5-axis lens shift OIS and autofocus is configured to move the lens in the X / Y / Z axes. In some embodiments, the pitch and yaw axis motion is for dynamic tilt adjustment functionality. Eight bimorph actuators are used to provide motion for autofocus and OIS using the techniques described herein. FIG. 61 illustrates an exploded view of an SMA system including an SMA actuator 6202 according to an embodiment including a bimorph actuator 6204 according to an embodiment configured as a 5-axis lens shift OIS and autofocus. FIG. 62 illustrates a cross section of an SMA system including an SMA actuator 6202 according to an embodiment including a bimorph actuator 6204 configured as a 5-axis lens shift OIS and autofocus. FIG. 63 illustrates a box bimorph actuator 6202 according to an embodiment configured as a 5-axis lens shift OIS and autofocus as manufactured before being molded to fit the system for use in an SMA system. Such systems can be configured to have high OIS strokes (e.g., ±200 μm or more) and high autofocus strokes (e.g., 400 μm or more). Additionally, such embodiments can be tuned to eliminate any tilt, eliminating the need for a separate autofocus assembly.

[0059] FIG. 64 shows an SMA system including an SMA actuator according to one embodiment including a bimorph actuator configured as an extrusion box. In some embodiments, the bimorph actuator assembly is configured to wrap around an object such as a lens carriage. There is a flexible section for low X / Y / Z stiffness because the circuit assembly is moving with the lens carriage. The end pads of the circuit are static. The extrusion box can be configured for both 4 or 8 bimorph actuators. Thus, the extrusion box can be configured as 4 bimorph actuators on the side for OIS that moves in the X and Y axes. The extrusion box can be configured as 4 bimorph actuators on the top and bottom for autofocus that moves in the z axis. The extrusion box can be configured as 8 bimorph actuators on the top, bottom and sides for OIS and autofocus that moves in the x, y and z axes and is capable of 3-axis tilt (pitch / ro / yaw). FIG. 65 shows an exploded view of an SMA system including an SMA actuator 6602 according to one embodiment including a bimorph actuator 6604 configured as an extruded out box. The SMA actuator is thus configured such that the bimorph actuator acts on the outer housing 6504 to move the lens carriage 6506 using the techniques described herein. FIG. 66 shows an SMA system including an SMA actuator 6602 according to one embodiment including a bimorph actuator configured as an extruded out box partially molded to receive the lens carriage 6603. FIG. 67 shows an SMA system including an SMA actuator 6602 including a bimorph actuator 6604 according to one embodiment configured as an extruded out box as manufactured before the bimorph actuator 6604 is molded to fit within the system.

[0060] FIG. 68 shows an SMA system including an SMA actuator 6802 according to an embodiment including a bimorph actuator 6806 configured as a 3-axis sensor-shifting OIS. In some embodiments, the z-axis movement comes from a separate autofocus system. Four bimorph actuators are configured to push on the sides of the sensor carriage 6804 to provide motion for the OIS using techniques described herein. FIG. 69 shows an exploded view of an SMA including an SMA actuator 6802 according to an embodiment including a bimorph actuator 6806 configured as a 3-axis sensor-shifting OIS. FIG. 70 shows a cross section of an SMA system including an SMA actuator 6802 according to an embodiment including a bimorph actuator 6806 configured as a 3-axis sensor-shifting OIS. FIG. 71 shows a box bimorph actuator 6802 component according to an embodiment configured as a 3-axis lens-shifting OIS during manufacture before being molded to fit the system for use in an SMA system. FIG. 72 shows a flexible sensor circuit for use in an SMA system configured as a 3-axis sensor-shifting OIS according to an embodiment. Such systems can be configured to have high OIS stroke OIS (e.g., ±200 μm or more) and high autofocus stroke (e.g., 400 μm or more). Additionally, such embodiments are configured to have a wide range of two-axis motion and excellent OIS dynamic tilt using four plain bearings, such as POM plain bearings. These embodiments are configured to easily integrate with AF designs (e.g., VCM or SMA).

[0061] FIG. 73 shows an SMA system including an SMA actuator according to an embodiment including a bimorph actuator 7404 configured as a 6-axis sensor-shifting OIS and autofocus. In some embodiments, the 6-axis sensor-shifting OIS and autofocus is configured to move the lens in the X / Y / Z / pitch / yaw / roll axes. In some embodiments, the pitch and yaw axis motion is for dynamic tilt adjustment functions. Eight bimorph actuators are used to provide motion for autofocus and OIS using the techniques described herein. FIG. 74 shows an exploded view of an SMA system including an SMA actuator 7402 according to an embodiment including a bimorph actuator 7404 configured as a 6-axis sensor-shifting OIS and autofocus. FIG. 75 shows a cross section of an SMA system including an SMA actuator 7402 according to an embodiment including a bimorph actuator configured as a 6-axis sensor-shifting OIS and autofocus. FIG. 76 shows a box bimorph actuator 7402 according to an embodiment configured as a 6-axis lens-shifting OIS and autofocus as manufactured before being molded to fit the system for use in an SMA system. FIG. 77 shows a flexible sensor circuit for use in an SMA system according to an embodiment configured as a 3-axis sensor-shifting OIS. Such a system can be configured to have a high OIS stroke (e.g., ±200 μm or more) and a high autofocus stroke (e.g., 400 μm or more). Furthermore, such an embodiment can be adjusted to eliminate any tilt, eliminating the need for a separate autofocus assembly.

[0062] FIG. 78 shows an SMA system including an SMA actuator according to an embodiment including a bimorph actuator configured as a 2-axis camera tilt OIS. In some embodiments, the 2-axis camera tilt OIS is configured to move the camera in the pitch / yaw axis. Four bimorph actuators are used to push the top and bottom of the autofocus for overall movement of the camera relative to the OIS pitch and yaw motion using the techniques described herein. FIG. 79 shows an exploded view of an SMA system including an SMA actuator 7902 according to an embodiment including a bimorph actuator 7904 configured as a 2-axis camera tilt OIS. FIG. 80 shows a cross section of an SMA system including an SMA actuator according to an embodiment including a bimorph actuator configured as a 2-axis camera tilt OIS. FIG. 81 shows a box bimorph actuator according to an embodiment configured as a 2-axis lens shift OIS as manufactured before being molded to fit the system for use in an SMA system. FIG. 82 shows a flexible sensor circuit for use in an SMA system configured as a 2-axis camera tilt OIS according to an embodiment. Such systems can be configured to have high OIS stroke (e.g., ±3 degrees or greater). These embodiments are configured to easily integrate with autofocus ("AF") designs (e.g., VCM or SMA).

[0063] FIG. 83 shows an SMA system including an SMA actuator according to an embodiment including a bimorph actuator configured as a 3-axis camera tilt OIS. In some embodiments, the 3-axis camera tilt OIS is configured to move the camera in pitch / yaw / roll axes. Four bimorph actuators are used to push the top and bottom of the autofocus for overall movement of the camera for the OIS pitch and yaw motion using the techniques described herein, and four bimorph actuators are used to push the sides of the autofocus for overall movement of the camera for the OIS roll motion using the techniques described herein. FIG. 84 shows an exploded view of an SMA system including an SMA actuator 8402 according to an embodiment including a bimorph actuator 8404 configured as a 3-axis camera tilt OIS. FIG. 85 shows a cross section of an SMA system including an SMA actuator according to an embodiment including a bimorph actuator configured as a 3-axis camera tilt OIS. FIG. 86 shows a box bimorph actuator according to an embodiment configured as a 3-axis camera tilt OIS as manufactured before being molded to fit the system for use in an SMA system. FIG. 87 shows a flexible sensor circuit used in an SMA system according to an embodiment configured as a 3-axis camera tilt OIS. Such a system can be configured to have a high OIS stroke OIS (e.g., ±3 degrees or more). These embodiments are configured to easily integrate with AF designs (e.g., VCM or SMA).

[0064] 88 shows example dimensions of a bimorph actuator of an SMA actuator according to an embodiment. The dimensions are of a preferred embodiment, but one of ordinary skill in the art will appreciate that other dimensions can be used based on the desired characteristics for the SMA actuator.

[0065] FIG. 89 illustrates a lens system for a folded camera according to one embodiment. The folded camera includes a folded lens 8902 configured to bend light into a lens system 8901 that includes one or more lenses 8903a-d. In some embodiments, the folded lens is any one or more of a prism and a lens. The lens system 8901 is configured to have a principal axis 8904 that is angled with respect to a transmission axis 8906 that is parallel to the direction of travel of the light before it reaches the folded lens 8902. For example, a folded camera is used in a camera phone system to reduce the height of the lens system 8901 in the direction of the transmission axis 8906.

[0066] An embodiment of the lens system includes one or more liquid lenses, such as those described herein. The embodiment shown in FIG. 89 includes two liquid lenses 8903b, 8903d, such as those described herein. The one or more liquid lenses 8903b, 8903d are configured to be actuated using techniques including those described herein. The liquid lenses are actuated using actuators including, but not limited to, buckle actuators, bimorph actuators, and other SMA actuators. FIG. 108 illustrates a liquid lens actuated using a buckle actuator 60, according to one embodiment. The liquid lens includes a molded ring coupler 64, a liquid lens assembly 61, one or more buckle actuators 60, such as those described herein, a sliding base 65, and a base 62. The one or more buckle actuators 60 are configured to move the molded ring / coupler 64 to change the shape of the flexible membrane of the liquid lens assembly 61 to move or shape the light beam, for example, as described herein. In some embodiments, three or four actuators are used. A liquid lens, alone or in combination with other lenses, can be configured to act as an autofocus or optical image stabilization mechanism. A liquid lens can also be configured to direct an image onto an image sensor in other ways.

[0067] 90 illustrates several embodiments of a lens system 9001 including liquid lenses 9002a-h that focus an image onto an image sensor 9004. As shown, the liquid lenses 9002a-h can be configured to include any lens shape and to be dynamically configured to adjust the light path through the lens using techniques including those described herein.

[0068] The lens system for the folded camera is configured to include an actuated folded lens 9100. One example of an actuated folded lens is a prism tilt, such as that shown in FIG. 91. In the example shown in FIG. 91, the folded lens is a prism 9102 disposed on an actuator 9104. The actuator includes an SMA actuator, including but not limited to those described herein. In some embodiments, the prism tilt is disposed on an SMA actuator, including four bimorph actuators 9106, such as those described herein. The actuated folded lens 9100 according to some embodiments is configured as an optical image stabilization mechanism using techniques including those described herein. For example, the actuated folded lens is configured to include an SMA system, such as that shown in FIG. 39. Another example of an actuated folded lens can include an SMA actuator, such as that shown in FIG. 21. However, the folded lens can include other actuators as well.

[0069] FIG. 92 illustrates a bimorph arm including an offset according to one embodiment. Bimorph arm 9201 includes a bimorph beam 9202 having a length 9208 and a shaped offset 9203. The shaped offset 9203 increases the mechanical advantage to generate higher forces than a bimorph arm without an offset. According to some embodiments, the depth of the offset 9204 (also referred to herein as bending plane z offset 9204) and the length of the offset 9206 (also referred to herein as valley width 9206) are configured to define characteristics of the bimorph arm, such as the peak force. For example, the graph in FIG. 106 illustrates the relationship between bending plane z offset 9204, valley width 9206, and peak force of a bimorph beam 9202 according to one embodiment.

[0070] The bimorph arm includes one or more SMA materials, such as SMA ribbons or wires 9210, such as those shown herein. The SMA material is attached to the beam using techniques including those described herein. In some embodiments, the SMA material, such as SMA wires 9210, is attached to the fixed end 9212 of the bimorph arm and to the load point end 9214 of the bimorph arm such that a shaped offset 9203 is between the ends to which the SMA material is attached. The ends of the SMA material are electrically and mechanically coupled, in various embodiments, to contacts configured to provide current to the SMA material using techniques including those known in the art. Bimorph arms including offsets can be included in SMA actuators and systems such as those described herein.

[0071] 93 illustrates a bimorph arm including an offset and limiter according to one embodiment. The bimorph arm 9301 includes a bimorph beam 9302 with a shaped offset 9303 and a limiter 9304 adjacent to the shaped offset 9303. The offset 9303 increases the mechanical advantage to generate higher forces than a bimorph arm 9301 without the offset, and the limiter 9304 prevents movement of the arm away from the free, load point end 9306 of the bimorph actuator. The bimorph arm 9301 including the shaped offset 9303 and limiter 9304 can be included in SMA actuators and systems such as those described herein. The bimorph arm 9301 includes one or more SMA materials such as SMA ribbons or SMA wires 9308, such as those described herein, attached to the bimorph arm 9301 using techniques including those described herein.

[0072] FIG. 94 illustrates a bimorph arm including an offset and limiter according to one embodiment. The bimorph arm 9401 includes a bimorph beam 9402 having a shaped offset 9403 and a limiter 9404 adjacent the shaped offset 9403. The limiter 9404 is formed as part of a base 9406 for the bimorph arm 9401. The base 9406 is configured to receive the bimorph arm 9401 and includes a recess 9408 configured to receive an offset portion of the bimorph beam. A bottom of the recess is configured as the limiter 9404 adjacent the shaped offset 9403. The base 9406 can also include one or more portions 9410 configured to support a portion of the bimorph arm when not actuated. The bimorph arm 9401 including the shaped offset 9403 and the limiter 9404 can be included in SMA actuators and systems such as those described herein. The bimorph arm 9401 includes one or more SMA materials, such as SMA ribbons or SMA wires, such as those described herein, attached to the bimorph arm 9401 using techniques including those described herein.

[0073] 95 illustrates an embodiment of a base including a bimorph arm including an offset according to an embodiment. The bimorph arm 9501 includes a bimorph beam 9502 with a shaped offset 9504. The bimorph arm can also include a limiter using techniques including those described herein. The bimorph arm 9501 includes one or more SMA materials such as SMA ribbons or SMA wires 9506, such as those described herein, attached to the bimorph arm 9501 using techniques including those described herein.

[0074] FIG. 96 illustrates an embodiment of a base 9608 including two bimorph arms including offsets, according to one embodiment. Each bimorph arm 9601a, 9601b includes a bimorph beam 9602a, 9602b with a shaped offset 9604a, 9604b. Each bimorph arm 9601a, 9601b includes one or more SMA materials, such as SMA ribbons or wires 9606a, 9606b, such as those described herein, attached to the bimorph arm 9501 using techniques including those described herein. Each bimorph arm 9601a, 9601b can also include a limiter using techniques including those described herein. Some embodiments include a base including three or more bimorph arms formed using techniques including those described herein. According to some embodiments, the bimorph arm 9601 is integrally formed with the base 9608. In other embodiments, one or more of the bimorph arms 9601a, 9601b are formed separately from the base 9608 and attached to the base 9608 using techniques including, but not limited to, soldering, resistance welding, laser welding, and adhesives. In some embodiments, two or more bimorph arms 9601a, 9601b are configured to act on a single object. This can allow for increased force to be applied to the object. The following graph in FIG. 107 shows an example of how box volume, an approximation of a box that encloses the entire bimorph actuator, relates to the work per bimorph component. The box volume is approximated using the length of the bimorph actuator 9612, the width of the bimorph actuator 9610, and the height of the bimorph actuator 9614 (collectively referred to as the "box volume").

[0075] FIG. 97 illustrates a buckler arm including a load point extension according to one embodiment. The buckler arm 9701 includes a beam portion 9702 and one or more load point extensions 9704a, 9704b extending from the beam portion 9702. Each end 9706a, 9706b of the buckler arm 9701 is configured to be attached to or integrally formed with a plate or other base using techniques including those described herein. The one or more load point extensions 9704a, 9704b according to some embodiments are attached to or integrally formed with the beam portion 9702 offset from the load points 9710a, 9710b of the beam portion 9702. The load points 9710a, 9710b are portions of the beam portion 9702 that are configured to transfer the force of the buckler arm 9701 to another object. In some embodiments, the load points 9710a, 9710b are in the center of the beam portion 9702. In other embodiments, the load points 9710a, 9710b are at a location other than the center of the beam portion 9702. The load point extensions 9704a, 9704b are configured to extend from where they are joined to the beam portion 9702 toward the load points 9710a, 9710b of the beam portion 9702 in the direction of the longitudinal axis of the beam portion 9702. In some embodiments, the ends of the load point extensions 9704a, 9704b extend to at least the load points 9710a, 9710b of the beam portion 9702. The buckler arm 9701 includes one or more SMA materials, such as SMA ribbons or SMA wires 9712, such as those described herein. The SMA materials, such as the SMA wires 9712, are attached to both ends of the beam portion 9702. The SMA materials are attached to both ends of the beam portion using techniques including those described herein. In some embodiments, the length of the load point extensions 9704a, 9704b can be configured to be any length that is included within the longitudinal length of the associated flat (non-actuated) beam portion 9702 of the buckler arm 9701.

[0076] 98 shows a buckler arm 9801 including a load point extension 9810 according to one embodiment in an actuated position. SMA material attached to both ends of beam section 9802 is actuated using techniques including those described herein. Load points 9804 allow the buckler arm 9801 to increase the stroke range up the buckler arm without stretching. Thus, a buckler arm including a load point extension allows for a larger maximum vertical stroke. Buckler arms including load point extensions can be included in SMA actuators and systems such as those described herein.

[0077] FIG. 99 illustrates a bimorph arm including a load point extension according to one embodiment. The bimorph arm 9901 includes a beam portion 9902 and one or more load point extensions 9904a, 9904b extending from the beam portion. One end of the bimorph arm 9901 is configured to be attached to or integrally formed with a plate or other base using techniques including those described herein. The end of the beam portion 9902 opposite the attached or integrally formed end is not fixed and is free to move. The one or more load point extensions 9904a, 9904b according to some embodiments are attached to or integrally formed with the beam portion 9902 offset from the free end of the beam portion 9902. The load point extensions 9904a, 9904b are configured to extend from where they are joined to the beam portion 9902 in a direction away from a plane that includes the longitudinal axis of the beam portion 9902. For example, the one or more load point extensions 9904a, 9904b extend in a direction that the free ends of the beam portions extend in when actuated. Some embodiments of the bimorph arm 9901 include one or more load point extensions 9904a, 9904b having a longitudinal axis that forms an angle with a plane that includes the longitudinal axis of the beam portion, the angle being in the range of 1 degree to 90 degrees. In some embodiments, the ends 9910a, 9910b of the load point extensions 9904a, 9904b are configured to engage an object configured to be moved.

[0078] The bimorph arm 9901 includes one or more SMA materials, such as SMA ribbons or wires 9906, such as those described herein. The SMA materials, such as SMA wires 9906, are attached to both ends of the beam portion 9902. The SMA materials are attached to both ends of the beam portion 9902 using techniques including those described herein. In some embodiments, the length of the load point extensions 9904a, 9904b can be configured to be any length. The location of the engagement point of an object by the ends 9910a, 9910b of the load point extensions 9904a, 9904b according to some embodiments can be configured to be anywhere along the longitudinal length of the beam portion 9902. The height of the ends of the load point extensions above the beam portion when the beam portion is flat (unactuated) can be configured to be any height. In some embodiments, the load point extensions can be configured to be above at least other portions of the bimorph arm when the bimorph arm is actuated.

[0079] FIG. 100 shows a bimorph arm including a load point extension according to one embodiment in an actuated position. SMA material attached to both ends of beam portion 2 is actuated using techniques including those described herein. The load point extension 10 allows the bimorph arm 1 to increase the stroke force on the bimorph arm without stretching. Thus, the bimorph arm 1 including the load point extension 10 allows for a greater force to be applied by the bimorph arm 1. The bimorph arm 1 including the load point extension 10 can be included in SMA actuators and systems such as those described herein.

[0080] FIG. 101 illustrates an SMA optical image stabilization mechanism according to one embodiment. SMA optical image stabilization mechanism 20 includes a moving plate 22 and a stationary plate 24. Moving plate 22 includes a spring arm 26 integrally formed therewith. In some embodiments, moving plate 22 and stationary plate 24 are each formed to be a single, integral plate. Moving plate 22 includes a first SMA material mounting portion 28a and a second SMA material mounting portion 28b. Stationary plate 24 includes a first SMA material mounting portion 30a and a second SMA material mounting portion 30b. Each SMA material mounting portion 28, 30 is configured to secure SMA material, such as SMA wire, to the plate using a resistance weld joint. The first SMA material attachment portion 28a of the movable plate 22 includes a first SMA wire 32a disposed between it and the first SMA material attachment portion 30a of the stationary plate, and a second SMA wire 32b disposed between it and the second SMA attachment portion 30b of the stationary plate 24. The second SMA material attachment portion 28b of the movable plate 22 includes a third SMA wire 32c disposed between it and the second SMA material attachment portion 30b of the stationary plate, and a fourth SMA wire 32d disposed between it and the first SMA attachment portion 30a of the stationary plate 24. Actuating each SMA wire using techniques including those described herein moves the movable plate 22 away from the stationary plate 24. FIG. 102 illustrates an SMA material attachment portion 40 of the movable portion, according to one embodiment. The SMA material attachment portion is configured to have SMA material, such as SMA wire 41, resistance welded to the SMA material attachment portion 40. FIG. 103 shows the SMA mounting portion 42 of the stationary plate to which the resistance welded SMA wire 43 is attached, according to one embodiment.

[0081] FIG. 104 illustrates an SMA actuator 45 including a buckle actuator according to one embodiment. Buckle actuator 46 includes buckle arms 47 such as those described herein. Buckle arms 47 are configured to move in the z-axis when SMA wires 48 are actuated and deactuated using techniques including those described herein. Each SMA wire 48 is attached to a respective resistance weld wire crimp 49 using resistance welding. Each resistance weld wire crimp 49 includes an isolated island 50 from the metal forming the buckle arm 47 on at least one side of the SMA wire 48. The island structure can be used to connect at least one side of the SMA wire to an isolated island structure formed in a base metal layer in other actuators, optical image stabilization, and autofocus systems, such as the OIS application shown in FIG.

[0082] 105a and 105b show a resistance weld crimp including islands for an SMA actuator according to one embodiment used to attach the SMA wire 48 to the buckle actuator 46 using techniques including those described herein. FIG. 105a shows the bottom of the SMA actuator 45. The SMA actuator 45 according to some embodiments is formed from a stainless steel base layer 51. A dielectric layer 52, such as a polyimide layer, is disposed on the bottom of the stainless steel base layer 51. A conductor layer 53 according to some embodiments is electrically connected to the stainless steel 50 through vias in the dielectric layer 52, which allows for electrical connection between the wire welded to the stainless steel island 50 and the conductor circuit attached to the stainless steel island. The island 50 according to some embodiments is etched from the stainless steel base layer. The dielectric layer 52 maintains the position of the island 50 within the stainless steel base layer 51. The island 50 is configured to attach the SMA wire to the island 50 using techniques including those described herein such as resistance welding. FIG. 105b shows the top of the SMA actuator 45 including the island 50. In some embodiments, a glue or adhesive may also be placed on top of the weld to aid in mechanical strength and act as a fatigue strain relief during operation and shock loading.

[0083] FIG. 108 includes a lens system including an SMA actuator including a buckle actuator according to one embodiment. The lens system includes a liquid lens assembly 61 disposed on a base 62. The lens system also includes a molding ring / coupler 64 that is mechanically coupled to the buckle actuator 60. An SMA actuator including a buckle actuator 60, such as those described herein, is disposed on a sliding base 65 that is disposed on the base 62. The SMA actuator is configured to move the molding ring / coupler 64 along the optical axis of the liquid lens assembly 61 by actuating the buckle actuator 60 using techniques including those described herein. This moves the molding ring / coupler 64 to change the focus of the liquid lens in the liquid lens assembly.

[0084] 109 illustrates a free load point end of a bimorph arm according to one embodiment. The free load point end 70 of the bimorph arm includes a flat surface 71 for attachment of SMA material such as SMA wire 72. The SMA wire 72 is attached to the flat surface 71 by a resistance weld 73. The resistance weld 73 is formed using techniques including those known in the art.

[0085] FIG. 110 illustrates a free load point end of a bimorph arm according to one embodiment. The free load point end 76 of the bimorph arm includes a flat surface 77 for attachment of an SMA material, such as an SMA wire 78. The SMA wire 78 is attached to the flat surface 77 by a resistance weld similar to that shown in FIG. 109. An adhesive 79 is placed on top of the resistance weld. This allows for a more reliable bond between the SMA wire 78 and the free load point end 76. The adhesive 79 can include, but is not limited to, a conductive adhesive, a non-conductive adhesive, and other adhesives known in the art.

[0086] 111 illustrates a bimorph arm free load point end according to one embodiment. The bimorph arm free load point end 80 includes a flat surface 81 for attachment of an SMA material, such as an SMA wire 82. A metal interlayer 84 is disposed on the flat surface 81. The metal interlayer 84 may include, but is not limited to, a gold layer, a nickel layer, or an alloy layer. The SMA wire 82 is attached to the metal interlayer 84 disposed on the flat surface 81 by a resistance weld 83. The resistance weld 83 may be formed using techniques including those known in the art. The metal interlayer 84 allows for better adhesion to the free load point end 80.

[0087] FIG. 112 illustrates a bimorph arm free load point end according to one embodiment. The bimorph arm free load point end 88 includes a flat surface 89 for attachment of an SMA material, such as an SMA wire 90. A metal interlayer 92 is disposed on the flat surface 89, including but not limited to a gold layer, a nickel layer, or an alloy layer. The SMA wire 90 is attached to the flat surface 89 by a resistance weld similar to that shown in FIG. 111. An adhesive 91 is disposed on the resistance weld, which allows for a more reliable bond between the SMA wire 90 and the free load point end 88. The adhesive 91 includes but is not limited to a conductive adhesive, a non-conductive adhesive, and other adhesives known in the art.

[0088] 113 illustrates a fixed end of a bimorph arm according to one embodiment. The fixed end 95 of the bimorph arm includes a flat surface 96 for attachment of an SMA material, such as an SMA wire 97. The SMA wire 97 is attached to the flat surface 96 by a resistance weld 98. The resistance weld 98 is formed using techniques including those known in the art.

[0089] FIG. 114 illustrates a fixed end of a bimorph arm according to one embodiment. The fixed end 120 of the bimorph arm includes a flat surface 121 for attaching an SMA material, such as an SMA wire 122. The SMA wire 122 is attached to the flat surface 121 by a resistance weld similar to that shown in FIG. 113. An adhesive 123 is placed on top of the resistance weld. This allows for a more reliable bond between the SMA wire 122 and the fixed end 120. The adhesive 123 can include, but is not limited to, a conductive adhesive, a non-conductive adhesive, and other adhesives known in the art.

[0090] FIG. 115 illustrates a fixed end of a bimorph arm according to one embodiment. The fixed end 126 of the bimorph arm includes a flat surface 127 for attaching an SMA material, such as an SMA wire 128. A metal interlayer 130 is disposed on the flat surface 127. The metal interlayer 130 may include, but is not limited to, a gold layer, a nickel layer, or an alloy layer. The SMA wire 128 is attached to the metal interlayer 130 disposed on the flat surface 127 by a resistance weld 129. The resistance weld 129 is formed using techniques including those known in the art. The metal interlayer 130 allows for better adhesion to the fixed end 126.

[0091] FIG. 116 illustrates a fixed end of a bimorph arm according to one embodiment. The fixed end 135 of the bimorph arm includes a flat surface 136 for attaching an SMA material, such as an SMA wire 137. A metal interlayer 138 is disposed on the flat surface 136, including but not limited to a gold layer, a nickel layer, or an alloy layer. The SMA wire 137 is attached to the flat surface by a resistance weld similar to that shown in FIG. 115. An adhesive 139 is disposed on the resistance weld, which allows for a more reliable bond between the SMA wire 137 and the fixed end 135. The adhesive 139 includes but is not limited to a conductive adhesive, a non-conductive adhesive, and other adhesives known in the art.

[0092] FIG. 117 illustrates a rear view of a fixed end of a bimorph arm according to one embodiment. The bimorph arm is constructed according to embodiments described herein. The fixed end 143 of the bimorph arm includes an island 144 isolated from an outer portion 145 of the fixed end 143. This allows the island 144 to be electrically and / or thermally isolated from the outer portion 145. In some embodiments, the SMA material attached to the opposite side of the fixed end 143 of the bimorph arm is electrically coupled to an SMA material, such as an SMA wire, through a via. The island 144 is disposed on an insulator 146, such as those described herein. The island 144 can be formed using etching techniques, including those known in the art.

[0093] 118 illustrates a bimorph arm free load point end 870 according to one embodiment. The bimorph arm free load point end 870 includes a flat surface 871 configured to include a radial surface area 874 extending from a resistance weld region 873. The radial surface area 874 includes a distal portion 876 and a proximal portion 875. The flat surface 871 is configured to have an SMA material, such as an SMA wire 872, attached to the flat surface 871. According to some embodiments, the SMA wire 872 is attached to the flat surface 871 by a resistance weld at the resistance weld region 873. The resistance weld is formed using techniques including those known in the art. In other embodiments, the SMA wire 872 is attached to the flat surface 871 using other attachment techniques including those described herein.

[0094] The temperature drop of the unfixed load point end 870 is relative to the phase transition temperature of the SMA wire 872. The radiating surface area 874 significantly increases the surface area of ​​the unfixed load point end 870.

[0095] The increased surface area improves temperature reduction at the unanchored load point end 870. The increased surface area allows for cooling that prevents phase transitions in the shape memory alloy during operation. 119 illustrates a free load point end 170 of a bimorph arm according to one embodiment. The free load point end 170 of the bimorph arm includes a flat surface 171 configured to include a radial surface area 174 extending from a resistance weld region 173.

[0096] Radiating surface area 174 includes a distal portion 176 and a proximal portion 175. Flat surface 171 is configured with an SMA material, such as an SMA wire 172, attached to flat surface 171. According to some embodiments, SMA wire 172 is attached to flat surface 171 by a resistance weld to resistance weld region 173. In other embodiments, SMA wire 172 is attached to flat surface 171 using other attachment techniques, including those described herein.

[0097] The free load point end 170 also includes a proximal opening 178 and a distal opening 179 separated by a resistance weld region 173. The proximal opening 178 and the distal opening 179 are formed using techniques including those known in the art. Although the openings 178 and 179 are shown as fully through features, in some instances they may be partially etched.

[0098] Proximal opening 178 and distal opening 179 physically interrupt planar surface 171 and define the location of resistance weld region 173. Openings 178 and 179 are configured to mitigate interference between wire 172 and planar surface 171 near resistance weld region 173, according to some embodiments.

[0099] 120 illustrates a bimorph arm free load point end 270 according to one embodiment. The bimorph arm free load point end 270 includes a flat surface 271 configured to include a radial surface area 274 extending from a resistance weld region 273. The flat surface 271 is configured to have an SMA material, such as an SMA wire 272, attached to the flat surface 271. According to some embodiments, the SMA wire 272 is attached to the flat surface 271 by a resistance weld to the resistance weld region 273. In other embodiments, the SMA wire 272 is attached to the flat surface 271 using other attachment techniques, including those described herein.

[0100] The free load point end 270 also includes a proximal opening 278 and a distal opening 279 separated by a resistance weld region 273. The free load point end 270 also includes an elongate opening 280 that corresponds to a section of the SMA wire 272. The elongate opening 280 can be removed to provide wire clearance for the SMA wire 272. In some embodiments, the elongate opening 280 extends from the proximal opening 278. Although the openings 278, 279, and 280 are shown as fully through features, in some examples they may be partially etched away.

[0101] Proximal opening 278 and distal opening 279 physically interrupt planar surface 271 and define the location of resistance weld region 273. Similarly, elongated opening 280 physically interrupts planar surface 271 and defines the location of SMA wire 272. Openings 278, 279, and 280 are configured to mitigate interference between wire 272 and planar surface 271 near resistance weld region 273, according to some embodiments.

[0102] FIG. 121 illustrates a free load point end 370 of a bimorph arm according to one embodiment. Flat surface 371 is configured with an SMA material, such as SMA wire 372, attached to flat surface 371. According to some embodiments, SMA wire 372 is attached to flat surface 371 by a resistance weld to resistance weld area 373, which is at least partially isolated by non-linear opening 378. In some configurations, non-linear opening 378 is U-shaped to physically isolate up to 90% of resistance weld area 373. Resistance weld area 373 can be attached on a weld tongue defined by non-linear opening 378. In other embodiments, SMA wire 372 is attached to flat surface 371 using other attachment techniques, including those described herein. Although non-linear opening 378 is shown as a fully through feature, in some examples it may be partially etched.

[0103] The increased surface area from the radiating surface area 374 allows for cooling that prevents phase transformation of the shape memory alloy during actuation. In some alternative embodiments, the resistance weld region 373 may be completely etched away from the free load point end 370. Alternatively, the resistance weld region 373 may include a partial etch slot to increase compliance of the tongue.

[0104] 122 illustrates a free load point end 470 of a bimorph arm according to one embodiment. An adjacent flat surface 471 is provided for attachment of SMA material such as SMA wire 472. SMA wire 472 is attached to flat surface 471 by resistance weld regions 473 that are separated, at least in part, by non-linear openings 478.

[0105] Resistance weld area 473 may be attached using a partially etched slot 479 in a non-linear opening 478. In some configurations, non-linear opening 478 physically interrupts flat surface 471 and defines the location of resistance weld area 473. Openings 178 and 179 are configured to mitigate interference between wire 172 and flat surface 171 near resistance weld area 173, according to some embodiments. Openings 178 and 179 are shown as fully through features, but in some examples may be partially etched.

[0106] The increased surface area from the radiating surface area 474 allows for cooling that prevents phase transformation of the shape memory alloy during operation. The disclosed embodiments can be applied to the fixed end of a bimorph arm, and Figures 123 to 125 are provided herein as example embodiments of the fixed end incorporating the disclosed embodiments.

[0107] 123 illustrates a fixed end of a bimorph arm according to one embodiment. Fixed end 895 of the bimorph arm includes a flat surface 896 for attachment of an SMA material, such as an SMA wire 897. SMA wire 897 is attached to flat surface 896 by a resistance weld region 898. Resistance weld region 898 is formed using techniques including those known in the art.

[0108] Fixed end 895 includes a proximal opening 893 and a distal opening 894 separated by a resistance weld region 898. Proximal opening 893 and distal opening 894 are formed using techniques including those known in the art.

[0109] Proximal opening 893 and distal opening 894 physically interrupt flat surface 896 and define the location of resistance weld region 898. Openings 893 and 894 are configured, according to some embodiments, to mitigate interference between SMA wire 897 and flat surface 896 near resistance weld region 898. Although openings 893 and 894 are shown as fully through features, in some examples they may be partially etched.

[0110] 124 illustrates a fixed end of a bimorph arm according to one embodiment. Fixed end 195 of the bimorph arm includes a flat surface 196 for attachment of an SMA material, such as an SMA wire 197. SMA wire 197 is attached to flat surface 196 by a resistance weld at resistance weld region 198. Resistance weld region 198 may be formed using techniques including those known in the art.

[0111] Fixed end 195 includes a proximal opening 193 and a distal opening 194 separated by a resistance weld region 198. Proximal opening 193 and distal opening 194 are formed using techniques including those known in the art.

[0112] Fixed end 195 also includes an elongated opening 160 that accommodates a section of SMA wire 197. Elongated opening 160 can be removed to provide wire clearance for SMA wire 197. In some embodiments, elongated opening 160 extends from distal opening 194.

[0113] Proximal opening 193 and distal opening 194 at least partially physically isolate resistance weld region 198. Elongated opening 160 physically interrupts flat surface 196 and defines the location of SMA wire 197. Openings 193 and 194 are configured to mitigate interference between SMA wire 197 and flat surface 196 near resistance weld region 198, according to some embodiments. Although openings 193 and 194 are shown as fully through features, in some examples they may be partially etched.

[0114] 125 illustrates a fixed end 295 of a bimorph arm according to one embodiment. The fixed end 295 of the bimorph arm includes a flat surface 296 for securing an SMA material such as an SMA wire 297. The SMA wire 297 is attached to the flat surface 296 by a resistance weld at a resistance weld region 298.

[0115] The resistance weld areas 298 are at least partially separated by the non-linear openings 294. In some configurations, the non-linear openings 294 are U-shaped to physically separate up to 90% of the resistance weld areas 298. The resistance welds 298 can be attached onto weld tongues defined by the non-linear openings 294.

[0116] The non-linear opening 294 physically interrupts the flat surface 296 and defines the location of the resistance weld region 298. The linear opening 294 is configured, according to some embodiments, to mitigate interference between the SMA wire 297 and the flat surface 296 near the resistance weld region 298. In some alternative embodiments, the resistance weld region 298 may be etched completely from the fixed end 295. Alternatively, the resistance weld region 298 may include a partial etch slot to reduce the contact area.

[0117] FIG. 126 illustrates a balanced bimorph actuator according to one embodiment. The balanced bimorph actuator 440 includes two bimorph arms 442, 443 formed and configured using techniques including those described herein. In some embodiments, the bimorph actuator 440 is secured to a base 441, such as a carriage for mounting to an outer housing. The bimorph actuator 440 is secured to the base using techniques including those known in the art such as adhesives and solders. The balanced bimorph actuator 440 includes two bimorph arms 442, 443 arranged in opposite directions, and is therefore configured to reduce the net frictional force of the bimorph actuator 440 by minimizing or canceling their own frictional components 444a, 444b. The frictional force components 444a, 444b of each bimorph arm 442, 443 act in a different direction than the desired force stroke 445a, 445b of each bimorph arm 442, 443. According to some embodiments, the balanced bimorph actuator 440 includes at least a first bimorph arm 442 and at least another bimorph arm 443 configured to have a friction force component 444a, 444b acting in the opposite direction to the first bimorph arm 442. In this way, the balanced bimorph actuator 440 is configured to balance the sliding friction caused by one or more bimorph arms due to the friction force component. This allows for more precise control with less or no need to actively counteract unwanted friction forces. Balanced bimorph actuators, including those described herein, overcome the problem of other bimorph actuators that create friction force components at their tips. These other bimorph actuators cause a push in the Y direction and also cause unwanted forces in the X direction by sliding in the X direction along the surface of the actuator's pushed member. This causes a small amount of unwanted motion in the X direction that the control system must compensate for. However, these compensated bimorph actuators also induce their own unwanted friction forces.This requires complex control algorithms to achieve good motion performance, for example for use in optical image stabilization systems.

[0118] FIG. 127 illustrates optical image stabilization including balanced bimorph actuators according to one embodiment. The balanced bimorph actuators 448a-d on all sides are positioned in opposite directions using techniques including those described herein, so they act to cancel their own frictional components. With near zero net friction, open loop position errors are minimal. Slight errors are due in some instances to typical assembly and component size tolerances and can be easily corrected by using a closed loop control system.

[0119] FIG. 128 illustrates a balanced bimorph actuator according to one embodiment. The balanced bimorph actuator 450 includes two bimorph arms 452a, 452b, such as those described herein, arranged in a mirror-symmetric orientation in alignment. In some embodiments, the bimorph actuator 450 is secured to a base 453, such as a carriage for mounting to an outer housing. The bimorph actuator 450 is secured to the base using techniques including those known in the art such as adhesives and solder. According to some embodiments, the first bimorph arm 452a is configured to have a friction force component 454a primarily in the direction of the fixed end 456a of the first bimorph arm parallel to the longitudinal axis of the balanced bimorph actuator. The second bimorph arm 452b is configured in alignment with the first bimorph arm 452a such that the fixed end 456b of the second bimorph arm is adjacent to the fixed end 456a of the first bimorph arm. The second bimorph arm 452b is configured to have a friction force component 454b in the opposite direction to the first bimorph arm 452a. This results in a bimorph actuator configured to reduce the net friction force of the bimorph actuator by minimizing or canceling the net friction force of the bimorph actuator. In some embodiments, the net friction force is approximately zero net total friction force of the balanced bimorph actuator. In some embodiments, each bimorph arm 452a, 452b of the balanced bimorph actuator includes an SMA wire 458a, 458b. The SMA wires 458a, 458b are connected in series and configured to receive equal currents in both wires. In some embodiments, the first SMA wire 458a is coupled to an actuation control via the first bimorph arm 452a coupled to the control input pad 451a, e.g., via a one-channel input for controlling the actuation of the actuator. A second SMA wire 458b is coupled to ground via a second bimorph arm 452b that is coupled to ground pad 451b.

[0120] FIG. 129 illustrates a balanced bimorph actuator according to an embodiment that includes a polyimide layer 459 configured to retain and isolate the metal components. Other embodiments of the balanced bimorph actuator do not include a polyimide layer. In some embodiments of the balanced bimorph actuator that do not include a polyimide layer, the control input pads, ground pads, and common base island are secured to the base layer between the fixed ends of the first bimorph arm and the fixed ends of the second bimorph arm. In some embodiments, the control input pads, ground pads, and common base island are secured to the base layer using an adhesive such as those known in the art. FIG. 130 illustrates a balanced bimorph actuator according to an embodiment that includes a common base island 460. The common base island 460 is configured to attach one end of a first SMA wire and one end of a second SMA wire. In some embodiments, the common base island 460 is electrically isolated from the control input pads 461a and ground pads 461b before any SMA wires are attached to the common base island 460. A common base island 460 is formed at the fixed ends of a first bimorph arm 462a and a second bimorph arm 462b.

[0121] FIG. 131 illustrates a balanced bimorph actuator according to one embodiment. The balanced bimorph actuator includes two bimorph arms 464a, 464b, such as those described herein, arranged in an opposite, aligned orientation. In some embodiments, the bimorph actuator is secured to a base 463, such as a carriage for mounting to an outer housing. The bimorph actuator is secured to the base using techniques including those known in the art such as adhesives and solders. According to some embodiments, the first bimorph arm 464a is configured to have a friction force component 466a primarily in the direction of the fixed end 468a of the first bimorph arm 464a parallel to the longitudinal axis of the balanced bimorph actuator. The second bimorph arm 464b is configured in line with the first bimorph arm 464a such that the fixed ends 468a, 468b of the bimorph arms 464a, 464b are at opposite ends of the bimorph actuator. Thus, the free end of the first bimorph arm 469a and the free end of the second bimorph arm 469b are disposed near each other. The second bimorph arm 464b is configured to have a friction force component 466b in the opposite direction to the first bimorph arm 464a. This results in a bimorph actuator configured to reduce the net friction force of the bimorph actuator by minimizing or canceling the net friction force of the bimorph actuator. In some embodiments, the net friction force is approximately zero net total friction force of the balanced bimorph actuator. In some embodiments, each bimorph arm 464a, 464b of the balanced bimorph actuator includes an SMA wire 467a, 467b. The SMA wires 467a, 467b are connected in series and configured to receive equal currents in both wires, for example, via a one-channel input to control the actuation of the actuator. In some embodiments, the first SMA wire 467a is coupled to an actuation control via a first bimorph arm 452a coupled to a control input pad 451a, e.g., via a one-channel input for controlling the actuation of an actuator.A second SMA wire 458b is coupled to ground via a second bimorph arm 452b that is coupled to ground pad 451b.

[0122] FIG. 132 shows a balanced bimorph actuator using techniques described herein according to one embodiment, including a polyimide layer 570 configured to retain and isolate the metal components. Other embodiments of the balanced bimorph actuator do not include a polyimide layer. In some embodiments of the balanced bimorph actuator that do not include a polyimide layer, a control input pad and a ground pad are secured adjacent to the first and second bimorph arms. In some embodiments, the control input pad and the ground pad are secured to the base layer using an adhesive such as those known in the art. FIG. 133 shows a balanced bimorph actuator using techniques described herein according to one embodiment, including a control input pad 572 and a ground pad 573.

[0123] FIG. 134 illustrates a balanced bimorph actuator according to one embodiment. The balanced bimorph actuator includes two bimorph arms 574a, 574b, such as those described herein, arranged in a mirror-symmetric orientation in alignment. In some embodiments, the bimorph actuator is secured to a base 571, such as a carriage for mounting to an outer housing. The bimorph actuator is secured to the base using techniques including those known in the art such as adhesives and solders. According to some embodiments, the first bimorph arm 574a is configured to have a friction force component 575a primarily in the direction of the fixed end of the first bimorph arm 576a parallel to the longitudinal axis of the balanced bimorph actuator. The second bimorph arm 574b is configured in alignment with the first bimorph arm 574a such that the fixed end of the second bimorph arm 576b is adjacent to the fixed end of the first bimorph arm 576a. The second bimorph arm 574b is configured to have a friction force component 575b in an opposite direction to the friction force component of the first bimorph arm 575a. This results in a bimorph actuator configured to reduce the net friction force of the bimorph actuator by minimizing or canceling the net friction force of the bimorph actuator. In some embodiments, the net friction force is approximately zero net total friction force of the balanced bimorph actuator. In some embodiments, a single SMA wire 578 is used, with each end of the SMA wire 578 being coupled to a respective non-fixed end of each bimorph arm 577a, 577b. The single SMA wire 578 allows for more stroke for the balanced bimorph actuator.

[0124] FIG. 135 illustrates a balanced bimorph actuator according to an embodiment using the techniques described herein including a single SMA wire 579. FIG. 136 illustrates a balanced bimorph actuator according to an embodiment using the techniques described herein configured for a single SMA wire and including a control input pad 480 and a ground pad 481. In some embodiments, the balanced bimorph actuator is configured to include a polyimide layer configured to retain and isolate the metal components. Other embodiments of the balanced bimorph actuator do not include a polyimide layer. In some embodiments of the balanced bimorph actuator that do not include a polyimide layer, the control input pad and the ground pad are secured to a base layer between the fixed ends of the first bimorph arm and the fixed ends of the second bimorph arm. In some embodiments, the control input pad and the ground pad are secured to the base layer using an adhesive such as those known in the art.

[0125] FIG. 137 illustrates a balanced bimorph actuator according to one embodiment. The balanced bimorph actuator includes two bimorph arms 482a, 482b, such as those described herein, arranged in a staggered orientation. In some embodiments, the bimorph actuator is fixed to a base 489, such as a carriage for mounting to an outer housing. The bimorph actuator is fixed to the base using techniques including those known in the art such as adhesives and solders. According to some embodiments, the first bimorph arm 482a is configured to have a friction force component 483a primarily in the direction of the fixed end of the first bimorph arm 484a parallel to the longitudinal axis of the first bimorph arm. The second bimorph arm 482b is configured to be staggered with the first bimorph arm 482a such that the longitudinal axis of the second bimorph arm is approximately parallel to the longitudinal axis of the first bimorph arm. Additionally, the fixed ends of the bimorph arms 484a, 484b are at opposite ends of the bimorph actuator. Thus, the free ends of the first bimorph arm 484a and the second bimorph arm 484b are staggered with respect to each other. The second bimorph arm 482a is configured to have a friction force component 483a in an opposite direction to the first bimorph arm 482a. This results in a bimorph actuator configured to reduce the net friction force of the bimorph actuator by minimizing or canceling the net friction force of the bimorph actuator. In some embodiments, the net friction force is approximately zero net total friction force of the balanced bimorph actuator. In some embodiments, each bimorph arm 482a, 482b of the balanced bimorph actuator includes an SMA wire 485a, 485b. SMA wires 485a, 485b are connected in series and configured to receive equal current in both wires via a single channel input for controlling actuation of an actuator, such as those described herein.

[0126] FIG. 138 illustrates a balanced bimorph actuator with alternating orientations according to one embodiment, including a polyimide layer 486 configured to retain and isolate the metal components. Other embodiments of the balanced bimorph actuator do not include a polyimide layer. In some embodiments of the balanced bimorph actuator that do not include a polyimide layer, a control input pad and a ground pad are secured adjacent to the first and second bimorph arms. In some embodiments, the control input pad and the ground pad are secured to the base layer using an adhesive, such as those known in the art. FIG. 139 illustrates a balanced bimorph actuator according to one embodiment, including a control input pad 487 and a ground pad 488.

[0127] FIG. 140 illustrates an optical image stabilization system including a balanced bimorph actuator according to one embodiment. The balanced bimorph actuators on all sides are arranged in opposite directions so that they act to cancel their own frictional components. Since there is nearly zero net friction, open loop position error is minimal. Slight errors are due in some instances to typical assembly and component size tolerances and can be easily corrected by using a closed loop control system.

[0128] FIG. 141 shows an exploded view of an optical image stabilization system including a balanced bimorph actuator according to one embodiment. The optical image stabilization is configured to receive bimorph actuators such as those described herein, which automatically sit flush within pockets 510a-510d on the periphery of the outer housing 511. This arrangement allows the X / Y footprint of the bimorph modules 512a-512d to be small by allowing the bimorph actuators 514a-514d, such as the balanced bimorph actuators described herein, to share the same X / Y space as the outer housing 511. This also simplifies assembly of the bimorph modules 512a-512d by allowing the bimorph actuators 510a-510d to be inserted from the outside in a final step. The outer housing 511 can be made of molded plastic, metal, or other materials.

[0129] FIG. 142 illustrates an optical image stabilization system including a balanced bimorph actuator according to one embodiment. An optical image stabilization outer housing 516 is configured to receive bimorph actuators 518a-d, such as those described herein, which automatically sit flush within pockets in the outer housing 516. This arrangement allows the X / Y footprint of the bimorph modules 520a-d to be small by having the bimorph actuators 518a-d, such as the balanced bimorph actuators described herein, share the same X / Y space as the outer housing. This also simplifies assembly of the bimorph modules 520a-d by allowing the bimorph actuators 518a-d to be inserted from the outside in a final step. The outer housing 516 can be made of molded plastic, metal, or other materials.

[0130] FIG. 143 illustrates a sensor-shifting optical image stabilization system including a bimorph actuator according to one embodiment. The optical image stabilization system is configured to receive a balanced bimorph actuator, such as those described herein, configured as balanced carriages / modules 522a-522d. The bimorph carriages / modules 522a-522d are configured to insert from outside the sensor-shifting OIS module. In some embodiments, the sensor-shifting OIS also induces rotation of the image sensor 524 using an off-center bimorph actuator design, which is mounted on a movable image sensor carriage 528 that can be controlled to suppress roll excitation as well as X / Y excitation. This arrangement allows the X / Y footprint of the bimorph modules 522a-522d to be small by allowing the bimorph actuator, such as the balanced bimorph actuators described herein, to share the same X / Y space as the outer housing 526. This also simplifies assembly of the bimorph modules 522a-522d by allowing the bimorph actuators to be inserted from the outside in a final step. The outer housing 526 can be made from molded plastic, metal or other materials.

[0131] FIG. 144 illustrates an optical image stabilization system including a balanced bimorph actuator according to one embodiment. The optical image stabilization is configured to receive bimorph actuators, such as those described herein, that automatically sit flush in pockets 530 in the outer housing 532 of the optical image stabilization. This arrangement allows the X / Y footprint of the bimorph modules 534a-d to be small by having the bimorph actuators, such as the balanced bimorph actuators described herein, share the same X / Y space as the outer housing 532. This also simplifies assembly of the bimorph modules 534a-d by allowing the bimorph actuators to be inserted from the outside in a final step. The outer housing 532 can be made of molded plastic, metal, or other materials.

[0132] Fig. 145 shows a metal outer housing 536 for an optical image stabilization system according to an embodiment described herein that is fabricated as a molded metal attached with molded plastic 538a-538d in an insert molding process. Fig. 146 shows an embodiment of the metal outer can / housing 536 that includes pockets 542a-542d formed in four sides of the metal outer can / housing 536 that are configured to allow for flush mounting of bimorph actuators 544a-544d such as those described herein.

[0133] FIG. 147 illustrates an exploded view of an optical image stabilization (OIS) system including a balanced bimorph actuator and a plurality of centering springs, according to one embodiment. The optical image stabilization system includes an autofocus (AF) actuator 400 having four AF solder connections 402 or other electrical connections that carry current between the AF actuator 400 and focus control circuitry. In some embodiments, the autofocus actuator 400 includes one or more SMA actuators, such as those disclosed herein. The AF actuator 400 is disposed on a base 404 that is coupled to the AF actuator 400, according to some embodiments. The base 404 includes four isolated sections, each of which is attached to a spring 406a-d, according to some embodiments. Base 404 and springs 406a-406d, in some embodiments, are each formed from a single planar component that is divided into four isolated sections to create four electrical leaf spring circuits for controlling object movement, e.g., X / Y axis movement for optical image stabilization and / or Z axis movement for autofocus.

[0134] In some embodiments, the isolated sections of the base 404 and / or the springs 406a-406d are formed using an etching process or other manufacturing techniques such as known in the art. To form the four leaf spring circuits, the springs 406a-406d are welded to the base 404 such that each one of the four springs 406a-406d is welded to one of the four isolated sections of the base 404. The welds, in some embodiments, are at weld points 408a-408d included in each of the four leaf spring circuits, securing the springs 406a-406d to the isolated sections of the base 404 to create four isolated electrical paths. In some embodiments, the four isolated electrical paths are configured to be used for closed loop AF. The four OIS solder connections 410a-410d are configured to connect the leaf spring circuits to an OIS control circuit included in the bimorph OIS actuator 412. The OIS control circuitry is configured to connect to a printed circuit board (PCB) such that the camera control circuitry can operate the AF actuator 400 and the OIS actuator 412, such as the embodiments disclosed herein.

[0135] FIG. 148 shows a top view of an OIS system including four leaf spring circuits. The leaf spring circuits 414a-414d are configured as stainless steel (SST) circuits to enable a low-cost solution to control the movement of the image sensor, according to some embodiments. In some embodiments, the leaf spring circuits 414a-414d are formed of gold-plated 100 micrometer stainless steel. The stiffness of the springs that comprise the leaf spring circuits 414a-414d allows for a reliable and consistent spring force that can be used to center the AF actuator relative to the image sensor or otherwise control the movement of the AF actuator. The springs 416a-416d included in the leaf spring circuits 414a-414d are configured to produce low stress during large changes in motion, e.g., positive or negative motion in the x-axis and / or y-axis. For example, in some embodiments, the maximum stress on the springs during a stroke movement of 330 microns is 425 Megapascals (Mpa). Minimizing stress on the springs increases their service life (e.g., having fatigue below an infinite fatigue limit of less than 638 MPa), thereby improving the reliability of the OIS system over other motion control solutions. The springs are also configured to provide a downward force to the bearings (e.g., bearings) of the support assembly, providing near-zero dynamic tilt shock to the AF module and / or OIS.

[0136] FIG. 149 shows a base including four springs. Springs 418a-418d, according to an embodiment, are free-formed to create a preload (e.g., the springs may be free-formed such that their free ends extend 6.4 millimeters (mm) from the base in the positive or negative z-axis direction). In some embodiments, the springs are free-formed to have a preload in the range including 15-35 millinewtons. The spring preload in the OIS system is configured to ensure that a moving mass, such as an AF actuator, is held against one or more bearings.

[0137] By free forming the springs 418a-418d, the deflection of the springs 418a-418d can be reduced (e.g., the deflection of the springs can be reduced to ±0.1 mm) and the overall height requirement of the leaf spring circuit can be reduced, e.g., the amount of space in the z-axis required for proper operation. FIG. 150 shows the spring 429 after it has been welded to a base to create the leaf spring circuit. Prior to free forming the spring, one or more flattened bends may be formed in the spring. In some embodiments, the spring 429 includes a flattened bend near each end of the spring 429. For example, the spring includes a first flattened bend 430 configured to have a bend in the negative direction, e.g., a negative 3.5 degree bend in the z-axis direction, and / or a second flattened bend 431 configured to have a bend in the positive direction, e.g., a positive 3.5 degree bend in the z-axis direction. In some embodiments, the flattened bend is in a range including 0 degrees ±7 degrees. Other embodiments of the spring include flattened bends configured to have a desired range of bends to meet design constraints. The flattened bends of the spring allow the spring to achieve a downward force (e.g., ±25 microNewtons (mN)) while minimizing the amount of spring deflection (e.g., less than 0.1 mm arm deflection at normal conditions, less than 0.2 mm arm deflection at full spring height). The flattened bends of the spring are also configured to allow the spring to move in one direction (e.g., in the positive z-axis direction) to minimize the clearance space required below the leaf spring circuit. By minimizing the amount of spring deflection and minimizing the spring deflection in the positive z-axis direction, the amount of space occupied by the leaf spring circuit is reduced (e.g., ±0.2 mm in the z-axis direction). Therefore, by flattening one or more bends in the spring in the leaf spring circuit, the impact of the OIS actuator on the overall camera height is minimized, allowing for the assembly of a smaller, more compact electronic camera system.

[0138] FIG. 151 illustrates a bimorph actuator including a crimp according to one embodiment. According to various embodiments, the bimorph actuator 1512 includes a beam 1514, such as those described herein, and one or more SMA materials 1516, such as SMA ribbons or wires 1516. In some embodiments, the SMA material, such as the SMA wire 1516, is attached to a fixed end 1518 of the bimorph actuator, such as a fixed end of a bimorph actuator described herein, and a load point end 1520 of the bimorph actuator, such as those described herein, such that the beam 1514 is between the ends to which the SMA material is attached. The fixed end 1518 includes a crimp portion 1522 configured to clamp a portion of the SMA wire 1516 to attach the wire to the fixed end 1518. The load point end 1520 includes a crimp portion 1524 configured to clamp a portion of the SMA wire 1516 to attach the SMA wire 1516 to the load point end 1520. In various embodiments, the ends of the SMA material are electrically and mechanically coupled to contacts configured to supply electrical current to the SMA material, using techniques including those known in the art.

[0139] It will be understood that terms such as "top," "bottom," "upper," "lower," and x-, y-, and z-directions used herein are convenient terms to indicate the spatial relationship of parts to one another rather than to any given spatial or gravitational orientation, and are therefore intended to encompass an assembly of components, whether the assembly is oriented in the particular orientation shown in the drawings and described in the specification, or upside-down, or in any other rotational variation thereof.

[0140] It is understood that the term "the present invention" as used herein should not be interpreted to mean that only a single invention having a single essential element or group of elements is presented. Similarly, it is understood that the term "the present invention" encompasses a plurality of separate innovations, each of which can be considered as a separate invention. Although the present invention has been described in detail with reference to preferred embodiments and drawings thereof, it should be apparent to those skilled in the art that various adaptations and modifications of the embodiments of the present invention can be achieved without departing from the spirit and scope of the present invention. Furthermore, the techniques described herein can be used to create devices having 2, 3, 4, 5, 6, or more generally n bimorph and buckle actuators. It is therefore to be understood that the detailed description as set forth above and the accompanying drawings are not intended to limit the scope of the present invention, which should be inferred only from the following claims and their appropriately interpreted legal equivalents.

Claims

1. An actuator, a plurality of bimorph arms configured to reduce a net frictional force of the plurality of bimorph arms; The plurality of bimorph arms are arranged in a line in a mirror-symmetric orientation; An actuator, wherein the aligned mirror-symmetric orientation includes a first bimorph arm of the plurality of bimorph arms and a second bimorph arm of the plurality of bimorph arms, the second bimorph arm being positioned in line with the first bimorph arm such that a fixed end of the second bimorph arm is adjacent to a fixed end of the first bimorph arm, and a free end of the first bimorph arm is positioned opposite the free end of the second bimorph arm.

2. each of the plurality of bimorph arms includes a shape memory alloy (SMA) wire; The actuator of claim 1 , wherein the shape memory alloy wires attached to the multiple bimorph arms are connected in series and configured to receive an electric current to each shape memory alloy wire to control actuation of the actuator.

3. the first bimorph arm is configured to have a friction force component in a direction of a fixed end of the first bimorph arm parallel to a longitudinal axis of the actuator; The actuator of claim 1 , wherein the second bimorph arm is configured to have a friction force component in an opposite direction from the first bimorph arm to reduce a net total friction force to zero.

4. 2. The actuator of claim 1, comprising a single shape memory alloy wire having a first end and a second end, the first end of the shape memory alloy being coupled to the first bimorph arm of the plurality of bimorph arms and the second end of the shape memory alloy being coupled to the second bimorph arm of the plurality of bimorph arms.

5. The actuator of claim 1 , wherein the plurality of bimorph arms are arranged in a staggered orientation.

6. 6. The actuator of claim 5, wherein the alternating orientation includes a first bimorph arm of the plurality of bimorph arms and a second bimorph arm of the plurality of bimorph arms, the second bimorph arm being staggered with the first bimorph arm such that a longitudinal axis of the second bimorph arm is parallel to a longitudinal axis of the first bimorph arm and a fixed end of the first bimorph arm is at an end of the actuator opposite an end of the actuator adjacent to the fixed end of the second bimorph arm.

7. the first bimorph arm is configured to have a friction force component in a direction of the fixed end of the first bimorph arm parallel to the longitudinal axis of the first bimorph arm; The actuator of claim 6 , wherein the second bimorph arm is configured to have a friction force component in an opposite direction to the first bimorph arm to reduce a net total friction force to zero.

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