Patent Description:
Aspects of the present invention relate to scanning mirror systems. More particularly, aspects of the present invention relate to creating electrical connections between the actuator frame of a piezoelectric MEMS scanning mirror system and the substrate separate from the structural adhesive creating the mechanical bond between the actuator frame and the substrate. To do so, a structural bond (with no conducive properties) is used to attach the actuator frame to the substrate. After the bond is fully formed, separate electric connections can be created in one of two ways. In one aspect, the actuator frame may be coated with a coating that enables a surface of the actuator frame to be wire bondable. A wire bond can then be created between the actuator frame and substrate. In another aspect, a trace of conductive material is deposited on the outside edge of the mechanical bond between the actuator frame and the substrate and a final protection layer may be applied over the conductive trace to protect the trace from mechanical or environmental damage. The result is a system with maximum mechanical performance and increased efficiency.

These and other aspects of the invention will become apparent to one of ordinary skill in the art upon a reading of the following description, drawings, and the claims.

The present invention is described in detail herein with reference to the attached drawing figures, wherein:.

The subject matter of the present disclosure is described with specificity herein to meet statutory requirements. However, the description itself is not intended to limit the scope of this patent. Rather, the inventors have contemplated that the claimed subject matter might also be embodied in other ways, to include different steps or combinations of steps similar to the ones described in this document, in conjunction with other present or future technologies. Moreover, although the terms "step" and/or "block" may be used herein to connote different elements of methods employed, the terms should not be interpreted as implying any particular order among or between various steps herein disclosed unless and except when the order of individual steps is explicitly described.

As noted in the Background, in traditional piezoelectric MEMS scanning mirror systems, a metal actuator frame (not compatible with wire bonding) acts as the common electrical connection for all of the piezoelectric elements (i.e., the actuators). Since the substrate serves as the electrical and mechanical interconnect for the device, an electrical connection must also be made between the metal actuator frame and the substrate. In previous devices, a conductive adhesive was typically used to mechanically and electrically connect the actuator frame to the substrate. However, conductive adhesives are not as mechanically strong as adhesives that are dedicated for structural purposes. The decrease in mechanical strength introduced reliability issues into the device.

In an attempt to prevent these reliability issues, the conductive and structural adhesives were mixed (e.g., ten percent conductive and ninety percent structural). However, the adhesives did not mix uniformly throughout the bond and variations in the mechanical strength and conductive properties resulted. For example, the conductive adhesive may be covered by the structural adhesive and conductive issues occur. Similarly, the structural adhesive may be covered or diluted at a place where the structural bond occurs, and structural issues may occur.

Ultimately, each iteration of the device suffered efficiency issues. As the efficiency decreases, the device ceases to function properly. In particular, additional modes of motion are created because the resonant frequency shifts due to the structural weakening of the bond. The wire bonds attached to the mirror provide a feedback element so the angle the central mirror is moving can be determined. As the bond fails, the required voltage must increase to move the anchor portions of the mirror at a greater angle to achieve the desired effect in the mirror. Eventually, the system is no longer able to supply enough voltage to move the mirror to the required angle. Even if the voltage supply is able to be increased, the actuator will eventually fail as well.

Aspects of the present invention relate to creating electrical connections between the actuator frame of a piezoelectric MEMS scanning mirror system and the substrate separate from the structural adhesive creating the mechanical bond between the actuator frame and the substrate. Initially, a structural bond (with no conducive properties) is used to attach the actuator frame to the substrate. After the bond is fully formed, separate electric connections can be created in one of two ways. In one aspect, the actuator frame may be coated with a coating that enables a surface of the actuator frame to be wire bondable. A wire bond can then be created between the actuator frame and substrate. In another aspect, a trace of conductive material is deposited on the outside edge of the mechanical bond between the actuator frame and the substrate and a final protection layer may be applied over the conductive trace to protect the trace from mechanical or environmental damage. Both the wire bond and the trace of conductive material can be utilized in one device for redundancy. Similarly, more than one wire bond or more than one trace of conductive material can be utilized in one device for redundancy. The result is a system with maximum mechanical performance and increased efficiency over previous devices.

Accordingly, one aspect of the present disclosure is directed to a wire bonded common electrical connection in a scanning mirror system. The system comprises an actuator frame consisting of a frame material coated with a coating that enables a surface of the actuator frame to be wire bondable. The system also comprises at least one actuator having a top electrode on a top surface of the actuator and a bottom electrode on a bottom surface of the actuator. The at least one actuator may be attached to a top surface of the actuator frame with a partially conductive adhesive. The system further comprises a mirror extending across a gap in a central mounting member of the actuator frame. Anchor portions of the mirror are attached to the top surface of the actuator frame with a structural adhesive. The system also comprises a substrate connected to a bottom surface of the actuator frame with a structural adhesive. An electrical pad on the substrate enables an electrical connection between the top electrode on the top surface of the at least one actuator and the substrate, the mirror and the substrate, and the top surface of the actuator frame to the substrate.

In another aspect, the present disclosure is directed to a wire bonded common electrical connection in a scanning mirror system. The system comprises an actuator frame coated with a coating that enables a surface of the actuator frame to be wire bondable. The system also comprises at least one actuator attached to a top surface of the actuator frame with a partially conductive adhesive. The system further comprises a mirror extending across a gap in central mounting member of the actuator frame. Anchor portions of the mirror are attached to the top surface of the actuator frame with a structural adhesive. The system also comprises a substrate connected to a bottom surface of the actuator frame with a structural adhesive having no conductive properties, an electrical pad on the substrate enabling an electrical connection between a top surface of the actuator frame and the substrate.

In yet another aspect, the present disclosure is directed to a conductive bridge in a piezoelectric MEMS scanning mirror system. The system comprises an actuator frame consisting of a frame material. The system also comprises at least one actuator having a top electrode on a top surface of the actuator and a bottom electrode on a bottom surface of the actuator. The at least one actuator may be attached to a top surface of the actuator frame with a partially conductive adhesive. The system further comprises a mirror extending across a gap in a central mounting member of the actuator frame. Anchor portions of the mirror are attached to the top surface of the actuator frame with a structural adhesive. The system also comprises a substrate connected to a bottom surface of the actuator frame with a structural adhesive having no conductive properties. The system further comprises a trace of conductive adhesive enabling an electrical connection between the top surface of the actuator frame and the substrate.

<FIG> schematically shows an example display device <NUM> in communication with a video source <NUM>. Display device <NUM> includes a controller <NUM> operatively coupled to a scanning mirror system <NUM> and to a light source <NUM>. Controller <NUM> is configured to control light source <NUM> to emit light based on video image data received from video source <NUM>. Light source <NUM> may include any suitable light-emitting element(s), such as one or more lasers, and may output light in any suitable wavelength ranges, such as red, green, and blue. In other examples, light source <NUM> may output substantially monochromatic light, or other wavelength bands than red/green/blue.

Scanning mirror system <NUM> comprises one or more scanning mirrors <NUM> controllable to vary an angle at which light from the light source is reflected to thereby scan an image. As mentioned above, the scanning mirror system <NUM> may include a single mirror driven in both horizontal and vertical directions, or two mirrors separately driven in horizontal and vertical directions. Light reflected by scanning mirror system <NUM> is directed toward an output <NUM> for display of a scanned image. Output <NUM> may take any suitable form, such as projection optics, waveguide optics, etc. As examples, display device <NUM> may be configured as a virtual reality head-mounted display (HMD) device with output <NUM> configured as an opaque surface, or as an augmented reality HMD device with the output configured as a see-through structure that allows virtual imagery to be combined with a view of the surrounding real-world environment. Display device <NUM> also may assume other suitable forms, such as that of a head-up display, mobile device screen, monitor, or television, as examples.

Scanning mirror system <NUM> further includes an electromechanical actuator system <NUM> comprising actuator(s) <NUM> to effect movement of the scanning mirror(s) <NUM>. Various type of actuators may be used to control a MEMS mirror system.

As illustrated in <FIG>, one or more of the scanning mirror(s) <NUM> and the electromechanical actuator system <NUM> are bonded to an actuator frame <NUM> by a structural adhesive interface <NUM>. In one example, the structural adhesive interface <NUM> includes both a non-conductive structural adhesive portion <NUM> and a conductive structural adhesive portion <NUM> arranged such that the non-conductive structural adhesive portion <NUM> at least partially surrounds and encompasses the conductive structural adhesive portion <NUM>. The controller <NUM> may be configured to drive the actuator(s) <NUM> of the electromechanical actuator system <NUM> via electricity conducted through the actuator frame <NUM> and the conductive structural adhesive portion <NUM> to the actuator(s) <NUM>.

<FIG> show a specific example of a scanning mirror system <NUM> that includes a scanning mirror assembly <NUM> comprising an example of an actuator frame <NUM>. Scanning mirror assembly <NUM> comprises a MEMS mirror <NUM> attached to the actuator frame <NUM> via a first flexure <NUM> and a second flexure <NUM>. First and second flexures <NUM> and <NUM> may provide respective pivots via which mirror <NUM> can rotate and thereby change its angular orientation to vary the angle at which light from a light source is reflected. Mirror <NUM> may scan in a horizontal or vertical direction, depending upon an orientation in which scanning mirror system <NUM> is incorporated into a display device.

The first flexure <NUM> of scanning mirror assembly <NUM> is connected to a first anchor portion <NUM>. This first anchor portion is affixed to a first moveable member <NUM> of the actuator frame <NUM> by a structural adhesive interface. In a similar manner, the second flexure <NUM> of scanning mirror assembly <NUM> is connected to a second anchor portion <NUM> that is affixed to a second moveable member <NUM> of the actuator frame <NUM> by a structural adhesive interface. As described in more detail below, actuators affixed to the moveable members are controlled to cause corresponding movement in the mirror <NUM>.

In this example, the scanning mirror system <NUM> includes an electromechanical actuator system comprising a first actuator pair affixed to the first moveable member <NUM> adjacent to the first flexure <NUM>, and a second actuator pair affixed to the second moveable member <NUM> adjacent to the second flexure <NUM>. The first actuator pair comprises first actuator <NUM> and second actuator <NUM>, and the second actuator pair comprises third actuator <NUM> and fourth actuator <NUM>.

The actuators may be controlled to cause a desired oscillation in the mirror <NUM>. For example, the actuators may comprise a lead zirconate titanate (PZT) material or piezoelectric ceramic material that changes dimension based upon an applied voltage. For example, upon receiving an electrical signal having a first polarity (e.g., positive), actuators <NUM> and <NUM> may apply a contractive force to portions of moveable members <NUM> and <NUM>, respectively, underlying these actuators. On the other hand, upon receiving the electric signal having the first polarity, actuators <NUM> and <NUM> may apply a dilative force to portions of moveable members <NUM> and <NUM>, respectively, underlying these actuators. An electrical signal having a second, different polarity (e.g., negative) may cause actuators <NUM> and <NUM> to apply a dilative force to the respective underlaying portions of the moveable members, and may cause actuators <NUM> and <NUM> to apply a contractive force to the respective underlaying portions of the moveable members <NUM> and <NUM>. The magnitude of force applied by actuators <NUM>, <NUM>, <NUM> and <NUM> may be controlled by controlling the magnitude of an electrical signal applied to the actuators. As discussed above, the electrical signal applied to the actuators may be conducted through the conductive structural adhesive portion <NUM> of the structural adhesive interface <NUM> bonding each actuator to respective underlaying portions of the moveable members <NUM> and <NUM>. In this manner, the electrical signal may be applied to the conductive material of the actuator frame <NUM> and conducted to each of the actuators <NUM>, <NUM>, <NUM> and <NUM> via the conductive structural adhesive portion <NUM>.

In other examples the electromechanical actuator system of scanning mirror system <NUM> may utilize any suitable type of actuators. For example, each actuator may comprise a magnetic actuator, wherein a magnetic force between magnetic elements can be varied via electrical signal. In other examples, each actuator may comprise an electrostatic actuator, where an electric field between electrodes can be varied to adjust contractive or dilative forces. As a further example, each electromechanical actuator may utilize one or more bimetallic strips, where differing coefficients of thermal expansion of different materials can be leveraged to vary the applied forces. It will also be appreciated that actuator(s) of an electromechanical actuator system may be arranged at other suitable locations in a scanning mirror system.

In this example, a central mounting member <NUM> of the actuator frame <NUM> is affixed to an underlying substrate <NUM> via a spacer <NUM>. In some examples the actuator frame <NUM> may comprise a metallic material, such as steel, and the substrate <NUM> may comprise a PCB, ceramic material, or any other suitable material. The spacer <NUM> may comprise any suitable metallic material, such as steel. The central mounting member <NUM> may be bonded to the spacer <NUM>, and the spacer bonded to the substrate <NUM> via the structural adhesive interface <NUM>, such that an electric signal may be conducted from the substrate <NUM> to the actuators <NUM>, <NUM>, <NUM> and <NUM>.

In the example of <FIG>, spacer <NUM> elevates the actuator frame <NUM> above the substrate <NUM> to thereby enable movement of the moveable members <NUM> and <NUM>. More particularly and as shown in <FIG>, spacer <NUM> creates gaps <NUM> and <NUM> between moveable members <NUM> and <NUM>, respectively, and the underlying substrate <NUM>. In this manner, the first moveable member <NUM> and the second moveable member <NUM> float above the substrate <NUM>, and thereby may cause movement of the mirror <NUM> via flexures <NUM> and <NUM>. In one example, each of the gaps <NUM> and <NUM> may be approximately <NUM> to <NUM>, or more specifically <NUM>, to enable y-axis movement of the first moveable member <NUM> and second moveable member <NUM> relative to the substrate <NUM>. In other examples, any other suitable gap distances may be utilized to accommodate different scanning mirror system configurations and desired mirror movements. In the present example, the spacer <NUM> has substantially the same shape as the mounting member <NUM> of the actuator frame <NUM>. In other examples, the spacer <NUM> may have a shape different from the mounting member <NUM>. As shown in <FIG>, the actuators <NUM>, <NUM>, <NUM> and <NUM> are bonded to respective underlaying portions of the moveable members <NUM> and <NUM> of the actuator frame <NUM> by partially conductive adhesive <NUM>.

As illustrated in <FIG>, the actuator frame <NUM> comprises a first hinge <NUM> that connects a central portion <NUM> of the mounting member <NUM> with a central portion <NUM> of the first moveable member <NUM>. In this example, the first hinge <NUM> is located substantially equidistant from the opposing ends <NUM> and <NUM> of the first moveable member <NUM>. Similarly, the central portion <NUM> of the first moveable member <NUM> is located substantially midway between the opposing ends <NUM> and <NUM> of the first moveable member. In this example, both central portion <NUM> and central portion <NUM> comprise an aperture. It will be appreciated that in other examples, the mounting member <NUM> and first moveable member <NUM> may have different configurations that include one or more apertures of different shapes, sizes, and/or locations, or configurations that include no apertures.

In a similar manner, actuator frame <NUM> comprises a second hinge <NUM> that connects central portion <NUM> of the mounting member <NUM> with a central portion <NUM> of the second moveable member <NUM>. As with the first hinge <NUM>, the second hinge <NUM> is located substantially equidistant from the opposing ends <NUM> and <NUM> of the second moveable member <NUM>. The central portion <NUM> of the second moveable member <NUM> is also located substantially midway between the opposing ends <NUM> and <NUM> of the second moveable member. In this example, both central portion <NUM> and central portion <NUM> comprise an aperture. As with the first moveable member <NUM>, in other examples the mounting member <NUM> and second moveable member <NUM> may have different configurations that include apertures of different shapes, sizes, and/or locations, or configurations that include no apertures. In some examples, actuator frame <NUM> may be formed from micromachined silicon dies.

As illustrated in <FIG>, each of the actuators <NUM>, <NUM>, <NUM>, and <NUM> may be bonded to respective underlaying portions of the moveable members <NUM> and <NUM> of the actuator frame <NUM> by partially conductive adhesive <NUM>. In one example, the anchor portion <NUM> and <NUM> connected to the mirror <NUM> may also be bonded to underlaying portions of the moveable members <NUM> and <NUM> by structural adhesive.

Referring now to <FIG>, a side elevation of a scanning mirror system <NUM> is illustrated, in accordance with aspects hereof. Some components referenced in <FIG> are not depicted in <FIG> and <FIG> to more clearly emphasize particular aspects of the present disclosure. Although each of <FIG> and <FIG> depict certain components, it will be appreciated that in various aspects of the present disclosure, the scanning mirror system may have different configurations that include one or more components described herein in different shapes, sizes, and/or locations (e.g., a different shaped actuator frame), or different configurations that include or exclude some of these components. As illustrated, the bottom surface of an actuator frame <NUM> is attached to a substrate <NUM> with a structural adhesive. Importantly, the structural adhesive has no conductive properties which enables maximum mechanical performance of the bond between the actuator frame <NUM> and the substrate <NUM> to be obtained. In aspects, the actuator frame <NUM> is made of a frame material that has a thermal expansion matched to a mirror. For example, the frame material may be alloy <NUM>. The actuator frame <NUM> is also coated with a coating (e.g., electroless nickel immersion gold coating or electroless nickel electroless palladium immersion gold coating). The coating enables a surface of the actuator frame <NUM> to be compatible with wire bonding that would not otherwise be wire bondable.

The scanning mirror system <NUM> also includes at least one actuator <NUM>, <NUM>. The actuator(s) <NUM>, <NUM> has a top electrode on the top surface and a bottom electrode on the bottom surface and is attached to a top surface of the actuator frame <NUM> with a partially conductive adhesive <NUM>. In this way, the bottom electrode of the actuator <NUM>, <NUM> is shorted to the top surface of the actuator frame <NUM>.

In the scanning mirror system <NUM>, the electrical connections and routing occur in the substrate <NUM>. The top electrode of the actuator is wire bonded (not shown) to an electrical pad (not shown) on the substrate <NUM>. In aspects, four wire bonds enable the electrical connection between the top surface of each of four actuators and the substrate <NUM>.

A mirror extends across a gap (not shown in <FIG>) in a central mounting member of the actuator frame <NUM>. Anchor portions <NUM>, <NUM> of the mirror are attached to the top surface of the actuator frame <NUM> with a structural adhesive <NUM>. The mirror is wire bonded (not shown) to an electrical pad (not shown) on the substrate <NUM>. In some aspects, four wire bonds enable the electrical connection between the mirror and the substrate <NUM>.

<FIG> is a side elevation of a scanning mirror system <NUM>, in accordance with aspects hereof. As illustrated, the scanning mirror system <NUM> includes four actuators <NUM>, <NUM>, <NUM>, <NUM>. As described above, each of the actuators <NUM>, <NUM>, <NUM>, <NUM> has a top electrode on the top surface and a bottom electrode on the bottom surface and is attached to a top surface of the actuator frame <NUM> with a partially conductive adhesive (not shown in <FIG>). The top electrode of each of the actuators <NUM>, <NUM>, <NUM>, <NUM> is wire bonded (not shown) to an electrical pad (not shown) on the substrate <NUM>. The wire bonds enable the electrical connection between the top surface of each of the actuators <NUM>, <NUM>, <NUM>, <NUM> and the substrate <NUM>.

As described above, a mirror <NUM> extends across an aperture <NUM> in a middle of the actuator frame <NUM>. Anchor portions <NUM>, <NUM> of the mirror <NUM> are attached to the top surface of the actuator frame <NUM> with a structural adhesive (not shown in <FIG>) and are connected to the mirror <NUM> by first flexure and second flexure <NUM>. The mirror is also wire bonded (not shown) to an electrical pad (not shown) on the substrate <NUM>. In some aspects, four wire bonds enable the electrical connection between the mirror and the substrate <NUM>.

<FIG> depicts a side elevation illustrating movement of a scanning mirror system <NUM>, in accordance with aspects hereof. The movement of the scanning mirror system <NUM> in <FIG> is exaggerated for illustrative purposes. For clarity, the piezoelectric effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress. Conversely, when an electric field is applied to these materials, the materials become stressed and can shrink or expand.

In the context of the scanning mirror system <NUM> described herein, when an electric field is applied across an actuator <NUM>, <NUM> in the Z direction, the actuators <NUM>, <NUM> attempt to shrink or expand in the X and Y direction. Since the actuators <NUM>, <NUM> are constrained by the actuator frame <NUM> (i.e., the actuator frame attempts to keep the actuator <NUM>, <NUM> the same size), the actuators <NUM>, <NUM> curve. In the case where an actuator on one side of the actuator frame <NUM> attempts to shrink (e.g., the actuator <NUM>) and an actuator on the other side of the actuator frame <NUM> attempts to expand (e.g., the actuator <NUM>), the actuators <NUM>, <NUM> curve in opposite directions, causing second moveable member <NUM> of the actuator frame <NUM> to tilt slightly. Since the anchor portion <NUM> of the mirror <NUM> is attached to the second moveable member <NUM>, the tilting of the anchor portion <NUM> causes movement of the mirror <NUM> via the flexure(s) (not shown in <FIG>) at a much higher degree.

Referring now to <FIG>, a side elevation of an exemplary wire bonded common electrical connection in a scanning mirror system <NUM> is illustrated, in accordance with aspects hereof. As illustrated, the scanning mirror system <NUM> includes a wire bond <NUM> between the common trace <NUM> on the substrate <NUM> to the surface of the actuator frame <NUM>.

As illustrated, the bottom surface of an actuator frame <NUM> is attached to a substrate <NUM> with a purely structural adhesive <NUM>. As emphasized above, the structural adhesive <NUM> has no conductive properties which enables maximum mechanical performance of the bond between the actuator frame <NUM> and the substrate <NUM> to be obtained. The actuator frame <NUM> is coated with a coating (e.g., electroless nickel immersion gold coating or electroless nickel electroless palladium immersion gold coating). The coating enables a surface of the actuator frame <NUM> to be compatible with wire bonding that would not otherwise be wire bondable. The wire bond <NUM> applied at the surface of the actuator frame <NUM> completes an electrical connection between the actuator frame <NUM> and the substrate <NUM> (by way of an electrical pad <NUM> on the substrate <NUM>). In some aspects the wire bond <NUM> is a gold wire and the coating on the surface of the actuator frame <NUM> and the trace on the electric pad <NUM> on the substrate <NUM> comprise a gold surface finish (e.g., electroless nickel immersion gold or electroless nickel electroless palladium immersion gold). In some aspects, multiple wire bonds can be applied for in different locations for redundancy. In some aspects, the wire bonded common electrical connection can be combined with the conductive bridge described with respect to <FIG> for redundancy.

<FIG> depicts a flow chart illustrating a method <NUM> of providing a wire bonded common electrical connection in a scanning mirror system. Although the method is presented in a particular order, it should be appreciated that the method can be performed in a variety of orders. As illustrated, at step <NUM>, a structural adhesive is dispensed on the substrate and the actuator frame (that has been coated with a coating compatible with wire bonds) is placed on the substrate. At step <NUM>, the system is placed in an oven and cured. A partially conductive adhesive is dispensed on the actuator frame, at step <NUM>, and the actuators are placed on the actuator frame. At step <NUM>, the system is placed in an oven and cured. A structural adhesive is dispensed on the actuator frame, at step <NUM>, and the mirror is placed on the actuator frame via the anchor portions of the mirror. At step <NUM>, the system is placed in an oven and cured. A wire bond is created, at step <NUM>, between the surface of the actuator frame and an electrical pad on the substrate.

Turning now to <FIG>, a side elevation of an exemplary conductive bridge in a scanning mirror system <NUM> is illustrated, in accordance with aspects hereof. As illustrated, the bottom surface of an actuator frame <NUM> is attached to a substrate <NUM> with a purely structural adhesive <NUM>. As mentioned above, the structural adhesive <NUM> has no conductive properties which enables maximum mechanical performance of the bond between the actuator frame <NUM> and the substrate <NUM> to be obtained. To create the electrical connection between the actuator frame and the substrate, a conductive adhesive <NUM> is dispensed at the edge of the actuator frame, down the side of the structural bond, and to an electrical pad on the substrate <NUM>. In some aspects, a protection layer is applied over the conductive adhesive <NUM> to protect the conductive bridge from mechanical or environmental damage. The conductive bridge can be applied in multiple locations between the actuator frame and the substrate for redundancy. In some aspects, the conductive bridge can be combined with the wire bonded electrical connection described with respect to <FIG> for redundancy.

<FIG> depicts a flow chart illustrating a method <NUM> of providing conductive bridge in a piezoelectric MEMS scanning mirror system. Although the method is presented in a particular order, it should be appreciated that the method can be performed in a variety of orders. As illustrated, at step <NUM>, a structural adhesive is dispensed on the substrate and the actuator frame is placed on the substrate. The system is placed in an oven and cured, at step <NUM>. A partially conductive adhesive is dispensed on the actuator frame, at step <NUM>, and the actuators are placed on the actuator frame. At step <NUM>, a conductive adhesive is dispensed at the edge of the actuator frame, down the side of the structural bond, and to an electrical pad on the substrate, forming the conductive bridge. The system is placed in an oven and cured, at step <NUM>. A structural adhesive is dispensed on the actuator frame, at step <NUM>, and the mirror is placed on the actuator frame via the anchor portions of the mirror. At step <NUM>, the system is placed in an oven and cured. A protection layer is applied over the conductive adhesive, at step <NUM>, to protect the conductive bridge from mechanical or environmental damage.

<FIG> shows an example head mounted display (HMD) device <NUM> that may include the example display device <NUM> illustrated in <FIG> and the example scanning mirror system <NUM> illustrated in <FIG>. The HMD device <NUM> may be worn by a user according to an example of the present disclosure. In other examples, an HMD device may take other suitable forms in which an at least partially see-through display is supported in front of a viewer's eye or eyes in an augmented reality HMD device configuration.

In the example of <FIG>, the HMD device <NUM> includes a frame <NUM> that wraps around the head of the user to position a display device <NUM> close to the user's eyes. The display device <NUM>, may, for example, take the form of the example display device <NUM> illustrated in <FIG> and described above. The frame supports additional components of the HMD device <NUM>, such as, for example, a processor <NUM> and input devices <NUM>. The processor <NUM> includes logic and associated computer memory configured to provide image signals to the display device <NUM>, to receive sensory signals from input devices <NUM>, and to enact various control processes described herein. The processor <NUM> may take the form of the controller <NUM> illustrated in <FIG>.

The input devices <NUM> may include various sensors and related systems to provide information to the processor <NUM>. Such sensors may include, but are not limited to, an inertial measurement unit (IMU) 1208A, one or more outward facing image sensors 1208B , and one or more inward facing image sensors 1208C. The one or more inward facing image sensors 1208B may be configured to acquire image data in the form of gaze tracking data from a wearer's eyes.

The one or more outward facing image sensors 1208B may be configured to capture and/or measure physical environment attributes of the physical environment in which the HMD device <NUM> is located. In one example, outward facing image sensors 1208b may include a visible-light camera configured to collect a visible-light image of a physical space. Further, the one or more outward facing image sensors 1208B may include a depth camera configured to collect a depth image of a physical space. More particularly, in one example the depth camera is an infrared time-of-flight depth camera. In another example, the depth camera is an infrared structured light depth camera.

Data from the outward facing image sensors 1208B may be used by the processor <NUM> to generate and/or update a three-dimensional (3D) model of the physical space. Data from the outward facing image sensors 1208B may be used by the processor <NUM> to identify surfaces of the physical space and/or measure one or more surface parameters of the physical space. The processor <NUM> may execute instructions to generate/update virtual scenes displayed on display device <NUM> and identify surfaces of the physical space in any suitable manner.

In augmented reality configurations of HMD device <NUM>, the position and/or orientation of the HMD device <NUM> relative to the physical environment may be assessed so that augmented-reality images may be accurately displayed in desired real-world locations with desired orientations. As noted above, the processor <NUM> may execute instructions to generate a 3D model of the physical environment including surface reconstruction information that may be used to identify surfaces in the physical space. In both augmented reality and non-augmented reality configurations of HMD device <NUM>, the IMU 1208A of HMD device <NUM> may be configured to provide position and/or orientation data of the HMD device <NUM> to the processor <NUM>.

With reference to <FIG>, computing device <NUM> includes a bus <NUM> that directly or indirectly couples the following devices: memory <NUM>, one or more processors <NUM>, one or more presentation components <NUM>, one or more input/output (I/O) ports <NUM>, one or more I/O components <NUM>, and an illustrative power supply <NUM>. Bus <NUM> represents what may be one or more busses (such as an address bus, data bus, or combination thereof). Although the various blocks of <FIG> are shown with lines for the sake of clarity, in reality, these blocks represent logical, not necessarily actual, components. For example, one may consider a presentation component such as a display device to be an I/O component. Also, processors have memory. The inventors hereof recognize that such is the nature of the art and reiterate that the diagram of <FIG> is merely illustrative of an exemplary computing device that can be used in connection with one or more aspects of the present technology. Distinction is not made between such categories as "workstation," "server," "laptop," "handheld device," etc., as all are contemplated within the scope of <FIG> and with reference to "computing device.

Computing device <NUM> typically includes a variety of computer-readable media. Computer-readable media can be any available media that can be accessed by computing device <NUM> and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer-readable media may comprise computer-storage media and communication media.

Computer-storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVDs) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computing device <NUM>. Computer storage media does not comprise signals per se.

Communication media typically embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. By way of example, and not limitation, communication media includes wired media, such as a wired network or direct-wired connection, and wireless media, such as acoustic, RF, infrared, and other wireless media. Combinations of any of the above should also be included within the scope of computer-readable media.

Memory <NUM> includes computer storage media in the form of volatile and/or nonvolatile memory. The memory may be removable, non-removable, or a combination thereof. Exemplary hardware devices include solid-state memory, hard drives, optical-disc drives, etc. Computing device <NUM> includes one or more processors <NUM> that read data from various entities such as memory <NUM> or I/O components <NUM>. Presentation component(s) <NUM> presents data indications to a user or other device. Exemplary presentation components include a display device, speaker, printing component, vibrating component, and the like.

The I/O ports <NUM> allow computing device <NUM> to be logically coupled to other devices, including I/O components <NUM>, some of which may be built in. Illustrative components include a microphone, joystick, game pad, satellite dish, scanner, printer, wireless device, etc..

The I/O components <NUM> may provide a natural user interface (NUI) that processes air gestures, voice, or other physiological inputs generated by a user. In some instances, inputs may be transmitted to an appropriate network element for further processing. An NUI may implement any combination of speech recognition, touch and stylus recognition, facial recognition, biometric recognition, gesture recognition both on screen and adjacent to the screen, air gestures, head and eye tracking, and touch recognition associated with displays on the computing device <NUM>. The computing device <NUM> may be equipped with depth cameras, such as stereoscopic camera systems, infrared camera systems, RGB camera systems, and combinations of these, for gesture detection and recognition. Additionally, the computing device <NUM> may be equipped with accelerometers or gyroscopes that enable detection of motion. The output of the accelerometers or gyroscopes may be provided to the display of the computing device <NUM> to render immersive augmented reality or virtual reality.

Some aspects of computing device <NUM> may include one or more radio(s) <NUM> (or similar wireless communication components). The radio <NUM> transmits and receives radio or wireless communications. The computing device <NUM> may be a wireless terminal adapted to receive communications and media over various wireless networks. Computing device <NUM> may communicate via wireless protocols, such as code division multiple access ("CDMA"), global system for mobiles ("GSM"), or time division multiple access ("TDMA"), as well as others, to communicate with other devices. The radio communications may be a short-range connection, a long-range connection, or a combination of both a short-range and a long-range wireless telecommunications connection. When we refer to "short" and "long" types of connections, we do not mean to refer to the spatial relation between two devices. Instead, we are generally referring to short range and long range as different categories, or types, of connections (i.e., a primary connection and a secondary connection). A short-range connection may include, by way of example and not limitation, a Wi-Fi® connection to a device (e.g., mobile hotspot) that provides access to a wireless communications network, such as a WLAN connection using the <NUM> protocol; a Bluetooth connection to another computing device is a second example of a short-range connection, or a near-field communication connection. A long-range connection may include a connection using, by way of example and not limitation, one or more of CDMA, GPRS, GSM, TDMA, and <NUM> protocols.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

Claim 1:
A piezoelectric micro-electro-mechanical system (MEMS) scanning mirror system, the system comprising:
a conductive bridge,
an actuator frame (<NUM>) consisting of a frame material;
at least one actuator (<NUM>, <NUM>, <NUM>, <NUM>) having a top electrode on a top surface of the at least one actuator and a bottom electrode on a bottom surface of the at least actuator, the at least one actuator attached to a top surface of the actuator frame with a partially conductive adhesive (<NUM>);
the mirror (<NUM>) extending across a gap in a central mounting member of the actuator frame and attached with a structural adhesive (<NUM>) via anchor portions (<NUM>, <NUM>) of the mirror to the top surface of the actuator frame;
a substrate (<NUM>) connected to a bottom surface of the actuator frame with the structural adhesive (<NUM>), the structural adhesive having no conductive properties; and
the conductive bridge comprising a trace of conductive adhesive (<NUM>) enabling an electrical connection between the top surface of the actuator frame and the substrate.