Electromechanical design of MEMS scanner mirrors

Abstract

Device (100, 200, 300, 400, 500, 600, 700, 2000) that includes the following: a reflective section (102, 502, 602); a frame arranged at least partially around the reflective section (104, 504, 604); a drive coil (112, 512, 612) for receiving a first electric current to induce a movement of the reflecting section about a first axis in response to the received electric current; and a sensing coil (114, 514, 614) which is at least partially arranged around the drive coil and is physically separated from the reflecting section, wherein the induced motion serves to induce a second electric current in the sensing coil, wherein the second electric current serves to indicate a position of the reflecting section around the first axis (220, 720), wherein the drive coil is located on the reflective section and the sensing coil is arranged on the frame.

Description

AREA OF INVENTION

[0001] The embodiments described herein generally relate to microelectromechanical (MEMS) scanner mirrors and MEMS scanner mirror projection systems. The proposed solution is defined by claims 1 and 13. BACKGROUND

[0002] MEMS scanner mirrors based on laser projection systems show great promise for use in ultra-small and portable applications. The use of a drive coil and a sensing coil in a MEMS scanner mirror is known in principle from WO 2011 / 095231 A1, EP 1 338 912 A1, and US 6,464,363 B1. In one example of a MEMS scanner mirror projection system, a mirror can be arranged to rotate about two axes at right angles to each other in order to display pixels of a projected image onto a projection surface. In particular, the exemplary MEMS scanner mirror can reflect light emitted from one or more light sources to project the image. In some MEMS scanner mirror projection systems, two mirrors can be used, each of which can be arranged to rotate about one of two axes at right angles to each other.Laser light sources can be modulated while the MEMS mirror rotates to effectively pulse and sequentially display pixels to create a projected image. Specifically, the MEMS mirror can rotate to sweep across the entire area of ​​the projected image with reflected light quickly enough to produce an image that appears stable to the human eye. Advantageously, pixels can be projected only when needed using this method, allowing the laser light source(s) to be switched off for black areas of the projected image, thus conserving power.

[0003] One factor that can affect the displayed image quality of a MEMS-based projection system is the precision of the synchronization of the modulated laser pulses with the rotation of the mirror. If the synchronization between the modulated laser pulses and the mirror's rotation is insufficient, the same pixel may be pulsed at a slightly different timing from one frame to the next, resulting in a blurred image. Precise synchronization of the modulated laser pulses with respect to the mirror's rotation may require accurate sensing of the mirror's rotational angular position. A second factor that can influence image quality is the degree to which the MEMS mirror remains optically flat during operation. During operation, a MEMS mirror may be subjected to forces that can induce its bending; this phenomenon is sometimes referred to as dynamic deformation.Bending or other curvature of the mirror can induce a corresponding distortion of the generated image pixels, which can also be a cause of perceived blurriness of the image. List of characters Fig. Figure 1 shows a first example of a MEMS mirror. Fig. Figure 2 shows a first example of a MEMS scanner mirror projection system. Fig. Figure 3 shows a second example of a MEMS mirror. Fig. Figure 4 shows a third example of a MEMS mirror. Fig. Figure 5 shows a fourth example of a MEMS mirror. Fig. Figure 6 shows a fifth example of a MEMS mirror. Fig. Figure 7 shows a second example of a MEMS scanner mirror projection system. Fig. Figure 8 shows a first logic flow example. Fig. Figure 9 shows a second logic flow example. Fig. Figure 10 shows an example of a computer-readable medium. Fig. Figure 11 shows a first example system. Fig. Figure 12 shows a second example system. DETAILED DESCRIPTION

[0004] Several examples generally relate to electromechanical designs for MEMS scanner mirrors. In some examples, a drive coil may be arranged on a reflective portion of a MEMS scanner mirror. In some examples, a sensing coil may be arranged partially or completely on an outer frame portion of the MEMS scanner mirror. In other words, the drive coil may be located inside the sensing coil. In some examples, a multi-axis MEMS scanner mirror may be provided with a sensing coil arranged between two drive coils, each drive coil being configured to induce rotation of the MEMS scanner mirror in one direction along one of the axes. Further examples are described and claimed.

[0005] Fig. Figure 1 shows a block diagram of a MEMS scanner mirror 100 or “MEMS mirror” arranged according to various examples in the present disclosure. The MEMS mirror 100 can represent a MEMS mirror that may be implemented in a MEMS scanner mirror projection system. In particular, the MEMS mirror could be configured to sweep light beams across a projection surface while the light beams are modulated and / or pulsed to form pixels to display an image on the projection surface.

[0006] As shown, the MEMS mirror 100 can comprise a reflective section 102 and a frame 104. In general, the reflective section 102 and the frame 104 can be freestanding, movable parts, with the frame 104 generally connected to a fixed, non-movable section. The reflective section 102 can generally comprise a section of the MEMS mirror 100 on which a reflective surface has been applied, deposited, or otherwise created. The frame 104 can generally comprise a section of the MEMS mirror 100 that surrounds the reflective section 102.

[0007] The MEMS mirror 100 can comprise a drive coil 112 and a sensing coil 114. Generally, the drive coil 112 can be arranged inside the sensing coil 114. In some examples, the drive coil 112 can be located on the reflective section 102. More precisely, the drive coil can be arranged in a substrate, while the reflective section is formed above the drive coil (see, for example, Figure 1). Fig. 4) In some examples, the sensing coil 114 can be arranged on the frame 104 of the MEMS mirror 100. During operation, an electric current can be applied to the drive coil 112 to cause the reflecting section 102 to rotate about a number of axes (see, for example, Figure 1). Fig. 2 and Fig. 7) rotates. In some examples, the MEMS mirror 100 is magnetically actuated. For example, the MEMS mirror 100 can be arranged in a magnetic field and an electric current can be passed through the drive coil 112 to cause the MEMS mirror 100 to rotate and / or oscillate.

[0008] In some examples, arranging the drive coil 112 on the reflective section 102 may not significantly increase and / or affect the dynamic deformation of the reflective section 102 compared to designs where the drive coil 112 is located on the frame 104 and / or wound around an edge of the reflective section 102. In some embodiments, arranging the drive coil 112 on the reflective section 102 may allow for an increase in the number of individual coils comprising the drive coil 112 without introducing additional damping. Increasing the number of coils may result in lower power consumption (since less drive current is required) and a better signal-to-noise ratio (SNR) of the signal from the sensing coil 114 compared to designs where the drive coil 112 is located on the frame 104.The embodiments are not restricted in this context.

[0009] In some examples, the sensing coil 114 is arranged on the frame 104. More precisely, the sensing coil 114 can be arranged on and / or in a substrate around which the reflective section is formed (see e.g. Fig. 4) During operation, the sensing coil 114 can generate a current that indicates the position of the reflective section 102 while the reflective section 102 deforms and / or rotates about an axis (e.g., due to the application of an electric current to the 112 or the like). In some examples, rotation and / or vibration of the reflective section 102 can induce an electric current in the sensing coil 114. The induced electric current can be measured as an induced voltage signal, which can vary depending on the orientation of the sensing coil 114 relative to the drive coil 112 and thus of the reflective section 102. The induced current in the sensing coil can be used to determine an angular rotation and thus a position of the reflective section 102.

[0010] In some examples, arranging the sensing coil 114 on the frame 104 (e.g., as opposed to on the reflecting section 102 or the like) can reduce the sensitivity of the position sensing of the reflecting section 102 to temperature variation. For example, the temperature of the reflecting section 102 can rise when light (see, e.g., Fig. 2 and Fig. 7) strikes the reflective section 102. The position of the sensing coil 114 on the frame 104 can reduce the sensitivity to this temperature variation. More precisely, in some examples, the reflective section 102 may reflect only a portion of the light striking it, while the remainder is absorbed by the reflective section 102. For example, the reflective section 102 of the MEMS mirror 100 may reflect between 85 and 95% of the incident light, while absorbing 15 to 5%. The energy of the absorbed light can be converted into heat, which propagates from the center of the mirror toward the edges, potentially changing the resistance of the sensing coil and inducing thermal noise, which reduces the signal-to-noise ratio (SNR) of the induced voltage signal.Introducing a physical separation between the sensing coil 114 and the reflective section 102 can reduce the extent of heat exchange from the reflective section 102 to the sensing coil 114, thereby reducing thermal noise, increasing the signal-to-noise ratio (SNR) of the induced voltage signal, and enabling more precise position sensing. The embodiments are not limited in this respect.

[0011] It should be noted that in some examples, the sensing coil 114 could be partially or completely located on the reflective section 102, instead of being completely located on the frame 104 around the edges of the MEMS mirror 100. In various examples, arranging the drive coil 112 and the sensing coil 114 on the reflective section 102 can allow an increase in the number of individual coils that make up the drive coil 112 and / or the sensing coil 114 without introducing additional attenuation, which can lead to lower power consumption and / or a better signal-to-noise ratio (SNR).

[0012] In some examples, arranging the drive coil 112 and / or sensing coil 114 on the movable reflective section 102 can significantly limit the mechanical stress induced in the metal coils. Such stresses can lead to mechanical failure if they exceed the yield strength of the metal material used to form the coils. Furthermore, arranging the sensing coil 114 on a movable area with limited deformation, such as the reflective section 102, can reduce the distortion of the induced voltage and thus improve the signal-to-noise ratio (SNR) of the induced voltage signal.

[0013] Fig. Figure 2 shows a block diagram of a MEMS scanner mirror projection system 200 arranged according to various examples in the present disclosure. In general, the MEMS scanner mirror projection system 200 comprises a MEMS mirror, such as the MEMS mirror 100 from Fig. 1, and a light source 210. In some examples, the light source 210 can include various light sources, such as laser light sources, LED (light-emitting diode) light sources, or the like. During operation, the light source 210 can emit a light beam 212. In addition, the light source 210 can modulate and / or pulse the light beam 212 so that it corresponds to a specific pixel of an image.

[0014] In general, the light source 210 and the MEMS mirror 100 are arranged in optical communication with each other. Specifically, the light source 210 can emit the light beam 212, and the MEMS mirror 100 can receive the light beam 212. The MEMS mirror 100 can receive the light beam 212 from the reflecting section 102. During operation, the MEMS mirror 100 can be rotated about a number of axes, such as the axis 220. In particular, the MEMS mirror 100 can be rotated about the axis 220 to sweep a projection surface (not shown) with the received light beam 212. In other words, the MEMS mirror 100 can be rotated about the axis 220 to modify the direction in which the laser light beam 212, which strikes the reflecting section 102, is reflected.

[0015] It should be noted that the MEMS scanner mirror projection system 200 can be configured to sweep across multiple axes (e.g., 2D projection systems or the like) with the light beam 212. For example, the MEMS scanner mirror projection system 200 could be used with a 2D MEMS mirror (see, e.g., Fig. 5- Fig. 7) be carried out. Examples are not limited in this context.

[0016] Fig. Figure 3 shows a block diagram of a MEMS mirror 300 arranged according to various examples in the present disclosure. The MEMS mirror 300 can represent a MEMS mirror that could be implemented in a MEMS scanner mirror projection system (e.g., the system 200 or the like). In particular, the MEMS mirror could be configured to sweep light beams across a projection surface while the light beams are modulated and / or pulsed to form pixels in order to display an image on the projection surface.

[0017] As shown, the MEMS mirror 300 can comprise the reflective section 102 and the frame 104. Additionally, like the MEMS mirror 100, the MEMS mirror 300 can include a drive coil arranged inside a sensing coil, although this is not shown. For example, the drive coil 112 arranged in the sensing coil 114.

[0018] In some examples, the MEMS mirror 300 can include etched silicon sections 332 that can be created around the reflecting section 102 to minimize the dynamic deformation of the reflecting section 102. In particular, the etched sections 332 can minimize and / or reduce dynamic deformation that occurs during rotation (e.g., about the axis 220 or the like) of the reflecting surface 102. In some examples, such dynamic deformation can be largely due to a restoring force resulting from the application of a torsional beam during mirror rotation. Examples are not limited in this context.

[0019] Fig. Figure 4 shows a cutaway view of a MEMS mirror 400 arranged according to various examples in the present disclosure. The MEMS mirror 400 can represent a MEMS mirror that could be implemented in a MEMS scanner mirror projection system (e.g., the system 200 or the like). In particular, the MEMS mirror could be configured to sweep light beams across a projection surface while the light beams are modulated and / or pulsed to form pixels to display an image on the projection surface.

[0020] As shown, the MEMS mirror 400 can comprise a substrate 401, which includes a reflective section 102 and a frame section 104. In some examples, the substrate 401 can be a silicon-based substrate. The MEMS mirror 400 can be fabricated by embedding and / or depositing conductive traces 411 onto the substrate. For example, conductive traces 411 can be formed by an optical lithography process. In some examples, conductive traces 411 can be formed from a metallic material, such as gold, silver, copper, or the like. The conductive traces 411 can extend to and from the drive coil 112 and the sensing coil 114.

[0021] More precisely, the conductive tracks 411 can be formed in areas of the substrate corresponding to the frame 104 and the reflective surface 102 to arrange the sensing coils 114 and the drive coils 102 as described herein. Additionally, as shown, the drive coil 112 and the sensing coil 114 can be embedded in the substrate 401 in some examples. Subsequently, a reflective coating 403 can be arranged and / or deposited on the surface 405 of the substrate 401 to form the reflective surface 102.

[0022] Fig. Figure 5 shows a block diagram of a MEMS scanner mirror 500 or “MEMS mirror” arranged according to various examples in the present disclosure. The MEMS mirror 500 can represent a MEMS mirror that is part of a MEMS scanner mirror projection system (e.g., the system 200 from Fig. 2 or the like). In particular, the MEMS mirror 500 could be designed to sweep light beams across a projection surface while the light beams are modulated and / or pulsed to form pixels to display an image on the projection surface.

[0023] As shown, the MEMS mirror 500 can comprise the reflective section 502, an inner frame 504, and an outer frame 506. Generally, the reflective section 502 can comprise a freestanding, movable MEMS mirror. In some examples, the reflective section 502 can be configured similarly to the reflective section 102, which is used in conjunction with Fig. 1- Fig. 4 is described. The reflective section 502 can, for example, comprise a section of the MEMS mirror 500 on which a reflective surface is attached, deposited, or otherwise fabricated. The inner frame 504 can generally comprise a section of the MEMS mirror 500 that surrounds the reflective section 502. In some examples, the reflective section 502 can be mechanically coupled to the inner frame 504 via the torsion bars 542. In some examples, the MEMS mirror 500 can include etched silicon sections 532 created around the reflective section 502 to minimize the dynamic deformation of the reflective section 502. The outer frame 506 of the MEMS mirror 500 can surround the inner frame 504 and be mechanically coupled to the inner frame 504 via torsion bars 542.The outer frame 506 of the MEMS mirror 500 can be mechanically coupled to the static section 546 via torsion bars 544.

[0024] The MEMS mirror 500 can comprise an inner drive coil 512, an outer drive coil 516, and a sensing coil 514. Generally, the sensing coil 514 can be arranged between the drive coils 512 and 516. In particular, the sensing coil 514 can be arranged on the inner frame 504. The inner drive coil 512 can be arranged on the reflective section 502, while the outer drive coil 516 is arranged on the outer frame 506.

[0025] During operation, an electric current can be applied to the drive coils 512 and 516 to cause the reflective section 502 to rotate about multiple axes. In some examples, an electric current can be selectively applied to one of the drive coils 512 and / or 516 to adjust the rotation speed for one of the axes. In some examples, the MEMS mirror 500 can be magnetically actuated. For example, the MEMS mirror 500 can be positioned in a magnetic field, and an electric current can be passed through the drive coils 512 and / or 516 to cause the MEMS mirror 500 to rotate and / or vibrate.

[0026] Fig. Figure 6 shows a block diagram of a MEMS scanner mirror 600 or “MEMS mirror” arranged according to various examples in the present disclosure. The MEMS mirror 600 can represent a MEMS mirror that is part of a MEMS scanner mirror projection system (e.g., the system 200 from [reference]). Fig. 2 or the like). In particular, the MEMS mirror could be designed to sweep light beams across a projection surface while the light beams are modulated and / or pulsed to form pixels to display an image on the projection surface. It should be noted that the MEMS mirror 600 is similar to the MEMS mirror 500, except that the shape of the MEMS mirror 600 is oval, as opposed to the square or rectangular shape of the MEMS mirror 500. However, it should be noted that exemplary MEMS mirrors of the present disclosure may have any geometric shape, such as square, rectangular, circular, oval, polygonal, or the like.

[0027] As shown, the MEMS mirror 600 can comprise the reflective section 602, an inner frame 604, and an outer frame 606. Generally, the reflective section 602 can comprise a portion of the MEMS mirror 600 onto which a reflective surface has been attached, deposited, or otherwise fabricated. The inner frame 604 can generally comprise a portion of the MEMS mirror 600 that surrounds the reflective section 602. In some examples, the reflective section 602 can be mechanically coupled to the inner frame 604 via torsion bars 652. In some examples, the MEMS mirror 600 can include etched silicon sections 632 created around the reflective section 602 to minimize the dynamic deformation of the reflective section 602.The outer frame 606 of the MEMS mirror 600 can surround the inner frame 604 and be mechanically coupled to the inner frame via torsion bars 642. The outer frame 606 of the MEMS mirror 600 can be mechanically coupled to the static section 646 via torsion bars 644.

[0028] The MEMS mirror 600 can comprise the inner drive coil 612, the outer drive coil 616, and the sensing coil 614. Generally, the sensing coil 614 can be arranged between the drive coils 612 and 616. In particular, the sensing coil 614 can be arranged on the inner frame 604. The inner drive coil 612 can be arranged on the reflective section 602, while the outer drive coil is arranged on the outer frame 606.

[0029] During operation, an electric current can be applied to the drive coils 612 and 616 to cause the reflective section 602 to rotate about multiple axes. In some examples, the electric current can be selectively applied to one of the drive coils 612 and / or 616 to adjust the rotation speed for one of the axes. In some examples, the MEMS mirror 600 can be magnetically actuated. For example, the MEMS mirror 600 can be positioned in a magnetic field, and an electric current can be passed through the drive coils 612 and / or 616 to cause the MEMS mirror 600 to rotate and / or vibrate.

[0030] In some examples, the inner drive coil 612 can comprise between 5 and 120 coils, with the coils spaced 2 to 15 µm apart. In some examples, the sensing coil 614 can comprise between 5 and 15 coils, with the coils spaced 2 to 15 µm apart. In some examples, the outer drive coil can comprise between 5 and 60 coils, with the coils spaced 2 to 15 µm apart.

[0031] Fig. Figure 7 shows a block diagram of a MEMS scanner mirror projection system 700, arranged according to various examples in the present disclosure. In general, the MEMS scanner mirror projection system 700 comprises a MEMS mirror, such as the MEMS mirror 600 from Fig. 6 and a light source 710. In some examples, the light source 710 can include various light sources, such as laser light sources, LED (light-emitting diode) light sources, or the like. During operation, the light source 710 can emit a light beam 712. In addition, the light source 710 can modulate and / or pulse the light beam 712 so that it corresponds to a specific pixel of an image.

[0032] In general, the light source 710 and the MEMS mirror 600 are arranged in optical communication with each other. Specifically, the light source 710 can emit the light beam 712, and the MEMS mirror 600 can receive the light beam 712. The MEMS mirror 600 can reflect the light beam 712 from the reflective section 602. During operation, the MEMS mirror 600 can be rotated about a number of axes, such as the axis 720 and the axis 730. In particular, the MEMS mirror 600 can be rotated about the axis 720 to sweep a projection surface (not shown) in a first direction with the received light beam 712. Additionally, the MEMS mirror 600 can be rotated about the axis 730 to sweep the projection surface in a second direction with the received light beam 712.In other words, the MEMS mirror 600 can be rotated about the axes 720 and / or 730 to modify the direction in which the laser light beam 712, which hits the reflecting section 602, is reflected.

[0033] Fig. Figure 8 shows a logic flow diagram 800 arranged according to various examples in the present disclosure. The logic flow diagram 800 can begin at block 810. At block 810, light is received at a MEMS scanner mirror, which is to be reflected onto a projection surface, the MEMS scanner mirror comprising a reflective section and a drive coil arranged at least partially on the reflective section. The MEMS scanner mirror (e.g., MEMS mirror 100, MEMS mirror 300, MEMS mirror 400, MEMS mirror 500, MEMS mirror 600, or the like) can receive light (e.g., light 212, light 712, or the like) which is to be reflected by a reflective section of the MEMS scanner mirror. As a specific example, MEMS mirror 600 can receive light 712 at the reflective section 602. As shown, for example, in Fig. Figure 6 shows that the MEMS scanner mirror 600 includes a drive coil 612 arranged near the reflecting section 602.

[0034] Block 820 then follows, in which a voltage control signal is received at the drive coil for the MEMS scanner mirror, the voltage control signal causing the MEMS scanner mirror to rotate about at least one axis. The drive coil (e.g., drive coil 112, drive coil 512, drive coil 612, or the like) can receive a voltage control signal to cause the MEMS scanner mirror, and in particular the reflective section, to rotate about at least one axis. For example, a voltage or current applied to the drive coil 612 of the MEMS mirror 600 can cause the reflective section 602 to rotate about the axis 720. According to another example, a voltage or current applied to the outer drive coil 616 of the MEMS mirror 600 can cause the reflective section 602 to rotate about the axis 730.

[0035] Fig. Figure 9 shows a logic flow 900 arranged according to various examples in the present disclosure. The logic flow 900 can begin at block 910. At block 910, an initial electrical current is received at a drive coil of a MEMS mirror. The MEMS mirror (e.g., MEMS mirror 100, MEMS mirror 300, MEMS mirror 400, MEMS mirror 500, MEMS mirror 600, or the like) can receive an initial electrical current at a drive coil (e.g., drive coil 112, drive coil 512, drive coil 612, or the like). In particular, during operation, an applied current can activate the drive coil to induce a rotation of the reflecting surface (e.g., 102, 502, 602, or the like) of the MEMS mirror about an axis. In some examples, Block 910 can receive multiple electrical currents through multiple drive coils.For example, a first applied electric current can activate the drive coil 612 to cause the reflective surface to rotate around the axis 730, while a second applied electric current can activate the drive coil 616 to cause the reflective surface to also rotate around the axis 720.

[0036] Block 920 then follows, in which a second electric current is induced in a sensing coil, partly based on the induced motion, the sensing coil being arranged around the drive coil. The motion of the reflecting section can induce a second electric current in the sensing coil (e.g., sensing coil 114, 514, 614, or the like), the induced second electric current being based, at least partly, on a position of the reflecting section around the axis (e.g., axis 220, axis 720, axis 730, or the like).

[0037] Fig. Figure 10 shows an embodiment of a storage medium 1000. The storage medium 1000 can be of a make. In some examples, the storage medium 1000 can be any non-volatile computer-readable or machine-readable medium, such as optical, magnetic, or semiconductor memory. The storage medium 1000 can store different types of computer-executable instructions (e.g., 1002). For example, the storage medium 1000 can store different types of computer-executable instructions for carrying out procedure 800. In some examples, the storage medium 1000 can store different types of computer-executable instructions for carrying out procedure 900.

[0038] Examples of computer- or machine-readable storage media include any tangible media capable of storing electronic data, including volatile or non-volatile memory, removable or non-removable memory, erasable or non-erasable memory, writable or overwritable memory, etc. Examples of computer-executable instructions include any type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, object-oriented code, visual code, and the like. The examples are not limited in this context.

[0039] Fig. Figure 11 shows a block diagram illustrating an example of an Optical System 2000. In general, the Optical System 2000 can be implemented in various projection systems. In some examples, the System 2000 can be implemented in a head-up display (HUD) system. Such a HUD system can be found, for example, in vehicles, aircraft, trains, ships, eyeglasses, head-mounted devices, or the like. It should be noted that the Optical System 2000 can be described as a light projection system. However, examples are not limited in this context.

[0040] The system 2000 can include a light source 2003. In some examples, the light source 2003 can be a laser light source emitting a light beam 2005. In some examples, the light beam 2005 can have linear polarization. In some examples, the light source 2003 can emit multiple light beams that are combined into a single light beam (e.g., by a beam combiner or the like).

[0041] The system 2000 additionally includes a scanner mirror system 2006. The light source 803 and the scanner mirror system 806 are arranged such that the scanner mirror system 2006 can receive light emitted by the light source 2003. In some examples, the scanner mirror system 2006 can be a microelectromechanical (MEMS) scanner mirror. Such a MEMS system can, for example, include a movable plate that incorporates a mirror 2007 arranged to rotate about two axes at right angles to each other. For example, this figure shows the system 2007, which includes the mirror 2007 arranged to rotate about axes 2009a and 2009b. In some examples, the mirror 2007 can rotate about only a single axis. In another example, the system 2000 can include multiple mirrors, for example, two mirrors arranged to rotate about axes at right angles to each other.Examples are not limited in this context.

[0042] In some examples, the MEMS scanner mirror can be magnetically actuated. In some examples, the MEMS scanner mirror can be electrically actuated, such as via a piezoelectric actuator or the like. In some examples, the MEMS scanner mirror 2007 can be implemented as the MEMS scanner mirror systems described herein (e.g., 100, 300, 400, 500 and / or 600).

[0043] In general, the scanner mirror system 2006 can sweep the light beam 2005 across a projection surface 2010 to project an image onto the surface. In some examples, the image is projected onto the surface and / or displayed on it. In other examples, the light striking the surface is reflected and refracted by the surface. For example, the light can be reflected to one or more exit pupils to project an image perceived by a user's eye.

[0044] Fig.Figure 12 shows a diagram of an embodiment of a system and in particular shows a platform 3000, which may comprise various elements. For example, this figure shows that the platform (the system) 3000 may include a processor / graphics core 3002, a chipset / platform control hub (PCH) 3004, an input / output (I / O) device 3006, random access memory (RAM) (such as dynamic RAM (DRAM)) 3008 and a ROM 3010, display electronics 3020, a projector 3022 (e.g., including MEMS mirrors 100, 200, 300, 400, 500, 800, or the like), and various other platform components 3014 (e.g., a fan, a cross-flow cooler, a heat sink, a DTM system, a cooling system, a housing, vents, etc.). The system 3000 can also include a wireless communication chip 3016 and a graphics device 3018. However, the embodiments are not limited to these elements.

[0045] As shown, the I / O device 3006, RAM 3008, and ROM 3010 are connected to the processor 3002 via the chipset 3004. The chipset 3004 can be connected to the processor 3002 via a bus 3012. Accordingly, the bus 3012 can comprise multiple lines.

[0046] The 3002 processor can be a central processing unit comprising one or more processor cores and can include any number of processors with any number of processor cores. The 3002 processor can include any type of processing unit, such as a CPU, multiprocessing unit, reduced instruction set computer (RISC), pipelined processor, complex instruction set computer (CISC), digital signal processor (DSP), etc. In some embodiments, the 3002 processor can be in the form of multiple separate processors located on separate integrated circuit chips. In some embodiments, the 3002 processor can be a processor with integrated graphics, while in other embodiments, the 3002 processor can be a graphics core or graphics cores.

[0047] Some embodiments may be referred to using the term "an embodiment" and related terms. These terms indicate that a particular feature, structure, or property described in connection with the embodiment is part of at least one embodiment. Where the term "in an embodiment" is used in different places in this description, it need not refer exclusively to the same embodiment. Furthermore, some embodiments may also be described using the terms "coupled" and / or "connected" and related terms. These terms are not necessarily synonymous.For example, some embodiments may be described as "connected" and / or "coupled" to indicate that two or more elements are in direct physical or electrical contact with each other. However, the term "coupled" can also mean that two or more elements are not in direct contact with each other but nevertheless cooperate or interact. Furthermore, aspects or elements of different embodiments may be combined.

Claims

[1] Device (100, 200, 300, 400, 500, 600, 700, 2000) comprising the following: a reflective section (102, 502, 602); a frame arranged at least partially around the reflective section (104, 504, 604); a drive coil (112, 512, 612) for receiving a first electric current to induce a movement of the reflecting section about a first axis in response to the received electric current; and a sensing coil (114, 514, 614) which is at least partially arranged around the drive coil and is physically separated from the reflecting section, wherein the induced motion serves to induce a second electric current in the sensing coil, wherein the second electric current serves to indicate a position of the reflecting section around the first axis (220, 720), wherein the drive coil is located on the reflective section and the sensing coil is arranged on the frame. [2] Device according to claim 1, wherein the device forms a microelectromechanical (MEMS) mirror, wherein the reflecting section serves to receive a light beam (212, 712, 2005) from a light source (210, 710, 2003), wherein the induced movement serves to sweep over a projection surface (2010) with the light beam in order to project an image. [3] Device according to claim 1, wherein the drive coil is arranged near the reflecting section. [4] Device according to claim 3, comprising a substrate (401), wherein the reflective section is arranged on the substrate and the drive coil is embedded in the substrate below the reflective section. [5] Device according to claim 4, comprising the following: an outer frame (506, 606) that is arranged at least partially around the frame; and an outer drive coil (516, 616) which is arranged at least partially around the sensing coil, wherein the outer drive coil serves to receive a third electric current in order to induce a second movement of the reflecting section about a second axis in response to the received electric current. [6] Device according to claim 5, comprising torsion bars (542, 642) to mechanically couple the frame to the outer frame, the torsion bars serving to provide the induced movement about the first axis. [7] Device according to claim 6, wherein the second electric current serves to indicate at least one of the positions of the reflecting section about the first axis or the second axis. [8] Device according to claim 7, comprising the following: a static section (546, 646) and outer torsion bars (544, 644) to mechanically couple the outer frame to the static section, the outer torsion bars serving to provide the induced second movement about the second axis. [9] Device according to any one of claims 6 to 8, wherein the outer drive coil comprises 5 to 120 individual coils, the individual coils being spaced 2 to 15 µm apart. [10] Device according to any one of claims 1 to 8, wherein the drive coil comprises 5 to 60 individual coils, the individual coils being spaced 2 to 15 µm apart. [11] Device according to any one of claims 1 to 8, wherein the sensing coil comprises 5 to 15 individual coils, the individual coils being spaced 2 to 15 µm apart. [12] Device according to any one of claims 1 to 8, wherein a perimeter of at least one of the reflecting section or the frame comprises a square, a rectangle, an oval, a circle or a polygon. [13] System (200, 700, 2000) comprising the following: a light source (210, 710, 2003) for emitting a light beam (212, 712, 2005); and a microelectromechanical (MEMS) mirror (100, 300, 400, 500, 600, 2006), wherein the MEMS mirror comprises the following: a reflective section (102, 502, 602) for receiving the light beam; a frame arranged at least partially around the reflective section (104, 504, 604); a drive coil (112, 512, 612) for receiving a first electric current to induce a movement of the reflecting section about a first axis in response to the received electric current in order to project the light beam onto a projection surface (2010); and a sensing coil (114, 514, 614) which is at least partially arranged around the drive coil and is physically separated from the reflecting section, wherein the induced motion serves to induce a second electric current in the sensing coil, wherein the second electric current serves to indicate a position of the reflecting section about the first axis (220, 720), wherein the drive coil is located on the reflective section and the sensing coil is arranged on the frame. [14] System according to claim 13, wherein the drive coil is arranged near the reflecting section. [15] System according to claim 14, wherein the MEMS mirror comprises a substrate (401), wherein the reflecting section is arranged on the substrate and the drive coil is embedded in the substrate below the reflecting section. [16] System according to claim 15, wherein the MEMS mirror comprises: an outer frame (506, 606) that is arranged at least partially around the frame; and an outer drive coil (516, 616) which is arranged at least partially around the sensing coil, wherein the outer drive coil serves to receive a third electric current in order to induce a second movement of the reflecting section about a second axis in response to the received electric current. [17] System according to claim 16, wherein the MEMS mirror comprises torsion bars (542, 642) to mechanically couple the frame to the outer frame, the torsion bars serving to provide the induced movement about the first axis. [18] System according to claim 17, wherein the second electric current serves to indicate at least one of the positions of the reflecting section about the first axis or the second axis. [19] System according to claim 18, wherein the MEMS mirror comprises: a static section (546, 646) and outer torsion bars (544, 644) to mechanically couple the outer frame to the static section, the outer torsion bars serving to provide the induced second movement about the second axis.

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