Mirror assemblies for imaging devices

Imaging devices and mirror assemblies for imaging devices are provided. The mirror assemblies include a first portion having a first cut face and formed of a transparent material, a second portion having a second cut face and formed of the transparent material, wherein the second cut face is assembled to the first cut face form a main body, and at least one reflective surface positioned between the first and second cut faces.

BACKGROUND

The subject matter disclosed herein relates to systems and methods for measuring three-dimensional (3D) coordinates of a scanned environment, and in particular, to mirror assemblies for use in 3D scanning systems.

A 3D imager is a portable device having a projector that projects light patterns on the surface of an object to be scanned. On such noncontact device may include time-of-flight techniques to be used to measure 3D coordinates (e.g. laser trackers, laser scanners, time-of-flight cameras, etc.). These devices emit a light beam and measure the amount of time it takes for light to travel to the surface and return to the device to determine the distance. Typically, the time-of-flight scanner is stationary and includes mechanisms to rotate about two orthogonal axis to direct the light beam in a direction. By knowing the distance and the two angles, 3D coordinates may be determined.

Some types of time-of-flight systems use rotating mirrors to reflect a projector or emitted electromagnetic radiation beam (e.g., a laser) and to reflect a returned electromagnetic radiation beam. The mirror is typically positioned relative to an electromagnetic radiation and a detector or sensor such that an emitted beam will be transmitted from the device, reflected off a surface within a scanned environment, and then return to the sensor/detector. The mirror may be angularly rotated by either a galvometer or a high speed motor. For systems that rotate the mirror 360 degree at high speed, the use of these high revolution per minute systems has constrained the packaging configurations thereof. For example, rotations of about 6,000 RPM may be used during scanning using time-of-flight systems. The forces applied to the components of the system (e.g., the mirror) can limit the manufacture and packaging arrangement thereof. Accordingly, improved systems may be beneficial and provide more packaging flexibility and reduced manufacturing costs.

BRIEF SUMMARY OF THE INVENTION

According to some embodiments, mirror assemblies are provided. The mirror assemblies include a first portion having a first cut face and formed of a transparent material, a second portion having a second cut face and formed of the transparent material, wherein the second cut face is assembled to the first cut face form a main body, and at least one reflective surface positioned between the first and second cut faces.

In addition to one or more of the features described above, or as an alternative, further embodiments of the mirror assemblies may include a first mounting assembly engaged with an end of the first portion opposite the first cut face, wherein the first mounting assembly is arranged to engage within an image scanner.

In addition to one or more of the features described above, or as an alternative, further embodiments of the mirror assemblies may include that the first mounting assembly includes a support element and a bearing element, wherein the support element engaged with the first portion.

In addition to one or more of the features described above, or as an alternative, further embodiments of the mirror assemblies may include that the first portion comprises an engagement surface that engaged the first portion to the first mounting assembly.

In addition to one or more of the features described above, or as an alternative, further embodiments of the mirror assemblies may include that the first mounting assembly is configured for engagement with a driving element to enable rotation of the at least one reflective surface.

In addition to one or more of the features described above, or as an alternative, further embodiments of the mirror assemblies may include a second mounting assembly engaged with an end of the second portion opposite the second cut face, wherein the second mounting assembly is arranged to engage within an image scanner.

In addition to one or more of the features described above, or as an alternative, further embodiments of the mirror assemblies may include that the first portion comprises a first window, wherein the mirror is arranged such that light can pass through an end of the first portion, reflect off the mirror, and pass through the first window.

In addition to one or more of the features described above, or as an alternative, further embodiments of the mirror assemblies may include that the second portion comprises a second window, wherein the at least one reflective surface is arranged such that light may pass through an end of the second portion, reflect off the at least one reflective surface, and pass through the second window.

In addition to one or more of the features described above, or as an alternative, further embodiments of the mirror assemblies may include that the at least one reflective surface is formed from at least one of a metallic coating and a di-electric coating.

In addition to one or more of the features described above, or as an alternative, further embodiments of the mirror assemblies may include that curved surfaces of the cylindrical body are at least one of treated, coated, and covered with absorbing material.

In addition to one or more of the features described above, or as an alternative, further embodiments of the mirror assemblies may include that the first portion is attached to the second portion using at least one of glue, adhesive, optical bonding, mechanical clamps, and mechanical fasteners.

According to some embodiments, imaging devices are provided. The imaging devices include a housing and a mirror assembly installed within the housing. The mirror assembly includes a first portion having a first cut face and formed of a transparent material, a second portion having a second cut face and formed of the transparent material, wherein the second cut face is assembled to the first cut face form a main body, and at least one reflective surface positioned between the first and second cut faces.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include a first mounting assembly engaged with an end of the first portion opposite the first cut face, wherein the first mounting assembly is arranged to engage within the housing.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include that the first mounting assembly includes a support element and a bearing element, wherein the support element engaged with the first portion.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include that the first portion comprises an engagement surface that engaged the first portion to the first mounting assembly.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include that the first mounting assembly is configured for engagement with a driving element to enable rotation of the at least one reflective surface.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include a second mounting assembly engaged with an end of the second portion opposite the second cut face, wherein the second mounting assembly is arranged to engage within an image scanner.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include at least one electromagnetic radiation device arranged to direct electromagnetic radiation at at least one of the first cut face and the second cut face.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include that the first portion comprises a first window, wherein the at least one reflective surface is arranged such that light can pass through an end of the first portion, reflect off the at least one reflective surface, and pass through the first window.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include that the second portion comprises a second window, wherein the at least one reflective surface is arranged such that light may pass through an end of the second portion, reflect off the at least one reflective surface, and pass through the second window.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include that the at least one reflective surface is formed from at least one of a metallic coating and a di-electric coating.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include that curved surfaces of the cylindrical body are at least one of treated, coated, and covered with absorbing material.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include that the first portion is attached to the second portion using at least one of glue, adhesive, optical bonding, mechanical clamps, and mechanical fasteners.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include at least one electromagnetic radiation device arranged to direct electromagnetic radiation at the at least one reflective surface.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include that the at least one electromagnetic radiation device comprises a first electromagnetic radiation device arranged to direct electromagnetic radiation at a first side of the at least one reflective surface and a second electromagnetic radiation device arranged to direct electromagnetic radiation at a second side of the at least one reflective surface.

In addition to one or more of the features described above, or as an alternative, further embodiments of the imaging devices may include that the first electromagnetic radiation device includes a coherent light generator and the second electromagnetic radiation device includes at least one of a color camera, a thermal camera, and a polarization camera.

DETAILED DESCRIPTION

Embodiments of the present disclosure provide for a mirror assembly, mirror rotors, and imaging devices/system with improved mirror arrangements. Embodiments provided herein are directed to cylindrical bodies formed from two portions with a mirror arranged between the two portions. Accordingly, advantageously, embodiments provided herein enable secure installation of the mirror within an imaging device and further allow for reduced costs and increased safety of such mirrors.

Referring now toFIGS. 1A-1C, schematic illustrations of a 3D scanner100(e.g., a laser scanner) that can incorporate embodiments of the present disclosure re shown. The 3D scanner100may be used for optically scanning and measuring a scanned environment using time-of-flight methods. The 3D scanner100includes, as shown, a measuring head102and a base104. The measuring head102is mounted to the base104such that the measuring head102can rotate with respect to the base104about a first axis106. In some embodiments, the rotation of the measuring head102may be driven by a first rotary drive (e.g., a motor), as will be appreciated by those of skill in the art. The rotation about the first axis106may be about the center of the base104.

The measuring head102includes a mirror108, which is arranged within the measuring head102to rotate about a second axis110. The rotation of the mirror108can be driven by a second rotary drive (e.g., a motor). Referring to a normal upright position of the 3D scanner100, the first axis106may be called the vertical axis or azimuth axis, while the second axis110may be called the horizontal axis or zenith axis. The 3D scanner100may comprise a gimbal point or center C10that is the intersection point of the first axis106and the second axis110.

The measuring head102is provided with an electromagnetic radiation emitter112, such as light emitter, that emits an emission light beam114. In an embodiment, the emission light beam114may be a coherent light such as a laser beam. As will be appreciated by those of skill in the art, the laser beam may have a wavelength range of approximately 300 to 11320 nanometers, for example, 790 nanometers, 905 nanometers, 1550 nanometers, or less than 400 nanometers. It should be appreciated that other electromagnetic radiation beams having greater or smaller wavelengths may also be used. The emission light beam114may be amplitude or intensity modulated, for example, with a sinusoidal waveform or with a rectangular waveform. Alternatively, the emission light beam114may be otherwise modulated, for example, with a chirp signal, or coherent receiver methods may be used. In the present embodiment, the emission light beam114is a continuous wave laser beam. However, it may also be a pulsed laser. The emission light beam114is emitted by the electromagnetic radiation emitter112onto the mirror108, where it is deflected to the environment of the 3D scanner100.

A reflected light beam, hereinafter called a reception light beam116, is reflected from the scanned environment by an object O that is within the scanned environment. The reflected or scattered light is intercepted by the rotary mirror108and directed onto a light receiver118with reception optics. The directions of the emission light beam114and the reception light beam116result from the angular positions of the measuring head102and the mirror108about the respective axes106,110. The angular positions in turn depend on the corresponding rotary drives. The angle of rotation about the first axis106is measured by a first angular encoder. The angle of rotation about the second axis110is measured by a second angular encoder.

A controller120is coupled to communicate with the electromagnetic radiation emitter112and the light receiver118inside the measuring head102. It should be appreciated that while the controller120is illustrated as being a single device or circuit, this is for exemplary purposes and the claims should not be so limited. In other embodiments, the controller120may be comprised of a plurality of devices or circuits. In some embodiments, a portion of the controller120may be arranged outside the measuring head102, for example, as a computer connected to the base104or other components of the 3D scanner100.

The operation of the 3D scanner100is controlled by controller120. The controller120is a suitable electronic device capable of accepting data and instructions, executing the instructions to process the data, and, in some configurations, presenting the results. The controller120may accept instructions through user interface, or through other means such as but not limited to electronic data card, voice activation means, manually-operable selection and control means, radiated wavelength and electronic or electrical transfer. The controller120may be a microprocessor, microcomputer, a minicomputer, an optical computer, a board computer, a complex instruction set computer, an ASIC (application specific integrated circuit), a reduced instruction set computer, a computer network, a desktop computer, a laptop computer, a scientific computer, a scientific calculator, or a hybrid of any of the foregoing.

The controller120is capable of converting an analog voltage or current level provided by sensors (e.g., encoders) into digital signal(s). Alternatively, sensors may be configured to provide a digital signal to the controller120, or an analog-to-digital (A/D) converter (not shown) maybe coupled between sensors and the controller120to convert the analog signal provided by sensors into a digital signal for processing by the controller120. The controller120uses the digital signals act as input to various processes for controlling the 3D scanner100. The digital signals represent one or more system data including but not limited to angular position about the first axis106, angular position about the second axis110, time-of-flight of the light beams114,116, and the like.

In general, the controller120accepts data from sensors, light emitter116and light receiver118, and is given certain instructions for the purpose of determining three-dimensional coordinates of points in the scanned environment. Further, the controller120may compare operational parameters to predetermined variances and if a predetermined variance is exceeded, the controller120can generate a signal that may be used to indicate an alarm to an operator. Additionally, the signal may initiate other control methods that adapt the operation of the 3D scanner100such as changing or stopping the rotation about the axis106once a predetermined angular position is achieved.

In some embodiments, the 3D scanner100may optionally include a secondary camera124that acquires additional images of a scanned environment. For example, the secondary camera124may be a color camera, a thermal camera, a polarization camera, or any other type of camera as desired. In one non-limiting example of using the secondary camera124, a color camera can generate two dimensional (2D) color images of the scanned environment as a scan is performed by the 3D scanner100. The 2D images may be synchronized with the acquired 3D coordinate points obtained by the 3D scanner100. This allows for the association of a color and/or a texture with the 3D coordinate point by the controller120. In some embodiments, the secondary camera124is disposed internally to the 3D scanner100and acquires images via the mirror108, and in other embodiments may be external thereto and connected by means as will be appreciated by those of skill in the art.

In addition to being coupled to one or more components within the 3D scanner100, controller120may also be coupled to external computer networks such as a local area network (LAN) and/or the Internet. A LAN interconnects one or more remote computers, which are configured to communicate with the controller120using a well-known computer communications protocol such as TCP/IP (Transmission Control Protocol/Internet Protocol), RS-232, ModBus, and the like. Additional systems may be connected to a LAN with respective controllers. Each of the systems may be configured to send and receive data to and from remote computers and other systems. In some embodiments, the LAN may be connected to the Internet. An Internet connection can allow the controller120to communicate with one or more remote computers or other systems connected to the Internet.

In an embodiment, the controller120can include various electronic and/or electrical components and elements, as shown inFIG. 1C. The controller120may include a processor126coupled to a random access memory device128, a non-volatile memory device130, a read-only memory device132, one or more input/output controllers and/or elements as known in the art, and an optional LAN interface device134via a data communications bus. In embodiments having a LAN interface device134, the LAN interface device134provides for communication between the controller120and a network in a data communications protocol supported by the network. The ROM device132can be configured to store an application code, e.g., main functionality firmware, including initializing parameters, and boot code, for the processor126. Application code also includes program instructions for causing the processor126to execute any operation control methods of the 3D scanner100, including starting and stopping operation, changing operational states of 3D scanner100, monitoring predetermined operating parameters, generation of alarms, etc. In an embodiment, the application code can create an onboard telemetry system that may be used to transmit operating information between the 3D scanner100and one or more remote computers or receiving locations. The information to be exchanged with remote computers and the controller120can include but are not limited to 3D coordinate data and images associated with a scanned environment. The controller120(or part of the 3D scanner100) can include a user interface136, illustratively shown as a display on the side of the measuring head102(e.g., shown inFIG. 1B).

The non-volatile memory device130may be any form of non-volatile memory such as an EPROM (Erasable Programmable Read Only Memory) chip, a disk drive, or the like. Stored in the non-volatile memory device130are various operational parameters for the application code. The various operational parameters can be input to non-volatile memory device130either locally, using a user interface136or through use of a remote computer, or remotely via the Internet using a remote computer. It will be recognized that application code can be stored in non-volatile memory device130or the read-only memory device132.

The controller120includes operation control methods embodied in application code. The methods are embodied in computer instructions written to be executed by the processor126, typically in the form of software. The software can be encoded in any language, including, but not limited to, assembly language, VHDL (Verilog Hardware Description Language), VHSIC HDL (Very High Speed IC Hardware Description Language), Fortran (formula translation), C, C++, Visual C++, C #, Objective-C, Java, Javascript ALGOL (algorithmic language), BASIC (beginners all-purpose symbolic instruction code), visual BASIC, ActiveX, HTML (HyperText Markup Language), Python, Ruby, and/or, for example, any combination or derivative of at least one of the foregoing. Additionally, an operator can use an existing software application such as a spreadsheet or database and correlate various cells with the variables enumerated in the algorithms. Furthermore, the software can be independent of other software or dependent upon other software, such as in the form of integrated software.

In an embodiment, the controller120may be configured to process data furnished to generate the 3D scans from data obtained at the light receiver118and the controller120. The 3D scans in turn are joined or registered in a common coordinate frame of reference. For registering, known methods can be used, such as by identifying natural or artificial targets (i.e., recognizable structures within a scanned environment) in overlapping areas of two or more frames. In an embodiment, the multiple frames are dynamically registered using a local bundle adjustment method. Through identification of these targets, the assignment of two 3D scans may be determined by means of corresponding pairs. A whole scene (a plurality of data or frames) is thus gradually registered by the 3D scanner100. In some embodiments, the data (e.g., individual frames) may be registered to a point cloud generated by a laser scanner.

In an embodiment, the controller120further includes an energy source, such as battery138. The battery138may be an electrochemical device that provides electrical power for the controller120. In an embodiment, the battery138may also provide electrical power to the 3D scanner100(e.g., electromagnetic radiation emitter112, light receiver118, and/or secondary camera124). In some embodiments, the battery138may be separate from the controller120(e.g. a battery pack). In an embodiment, a second battery (not shown) may be disposed in the measuring head102to provide electrical power to the imaging elements (e.g., electromagnetic radiation emitter112, light receiver118, and/or secondary camera124).

The controller120includes operation control methods embodied in application code. The controller120is configured to perform operational control methods that determine, for a multitude of measuring points X, a corresponding number of distances d between the 3D scanner100and the measuring points X on object O in the scanned environment, as shown inFIG. 1A. The distance to a particular measuring point X is determined based at least in part on the speed of light in air through which electromagnetic radiation propagates from the 3D scanner100to the measuring point X In an embodiment, the phase shift in the modulated light beam114sent to the measuring point X and received from it (light beam116), is determined and evaluated to obtain a measured distance d.

The speed of light in air depends on the properties of the air such as the air temperature, barometric pressure, relative humidity, and concentration of carbon dioxide. Such air properties influence the index of refraction of the air. The speed of light in air is equal to the speed of light in vacuum divided by the index of refraction. A laser scanner of the type discussed herein is based on the time-of-flight of the light in the air (i.e., the round-trip time for the light to travel from the device to the object and back to the device). A method of measuring distance based on the time-of-flight of light (or the time-of-flight of any type of electromagnetic radiation) depends on the speed of light in air and is therefore distinguishable from methods of measuring distance based on triangulation.

As noted above, in some embodiments, the measuring head102may include a user interface136(e.g., display device) integrated into the 3D scanner100. The user interface136can include a graphical touch screen. For example, the user interface136may allow an operator to provide measurement instructions to the 3D scanner100, in particular to set the parameters or initiate the operation of the 3D scanner100, and the user interface136may also display measurement results.

In an embodiment, the scanning of a scanned environment by the 3D scanner100may take place by rotating the mirror108relatively quickly about the second axis110while rotating the measuring head102relatively slowly about the first axis106, thereby moving the 3D scanner100in a spiral pattern. In a non-limiting example, the rotary mirror108may be driven to rotate at a maximum speed of about 6000 revolutions per minute. A scan is defined to be the entity of measuring points X in such a measuring. For such a scan, the center C10defines the origin of the local stationary reference system. The base104rests in this local stationary coordinate frame of reference.

In addition to measuring a distance d from the center C10to a measuring point X on the object O (as shown inFIG. 1A), the 3D scanner100may also collect gray-scale values related to a received optical power. The gray-scale value may be determined, for example, by integration of a bandpass-filtered and amplified signal in the light receiver118over a measuring period attributed to the measuring point X In some embodiments, color images can be generated by the secondary camera124. Through use of these color images, colors (R, G, B) or texture can be assigned to the measuring points X as additional values.

A rotor system (e.g., electromagnetic motor system) is used to spin or rotate the mirror within the measuring head, as will be appreciated by those of skill in the art (e.g., at about 6000 RPM). To enable such fast rotation, the rotor may be a certain length to enable balancing of the weight of the mirror during such rotation. A bearing system may support a mirror support upon which the mirror is attached. The mirror support is rotated within the bearing system by the rotor system.

As shown inFIG. 2, a mirror assembly200for use in a 3D scanner is schematically shown. The mirror assembly includes a mirror202that is angled to enable imaging as described above. An electric motor204is arranged to drive rotation of the mirror202. The motor204has a drive housing206which is fixedly connected to or part of a measuring head, such as shown above. The drive housing206has approximately the shape of a horizontal hollow cylinder and is arranged for engagement within a measuring head of a 3D scanner. A motor housing208is arranged within the drive housing206. The motor housing208may be configured to be rotationally symmetrical to a mirror axis210(e.g., the second axis110shown inFIGS. 1A-1B) and arranged around said mirror axis210. The motor housing208is attached at one end to the drive housing206and is otherwise spaced from an inner wall of drive housing206, producing an annular receiving space in drive housing206.

At least two bearings212,214are positioned within the motor housing208and support a shaft216. The shaft216is rotatable about the mirror axis210(and defines said mirror axis210). In some embodiments, various bearings arrangements may be employed, as will be appreciated by those of skill in the art. For example, in some non-limiting embodiments, the bearings212,214may be axially fixed against one another with one being a spring preloaded bearing so that the stiffness of the bearing arrangement is not position-dependent. A rotary support structure218may be arranged on the shaft216and project out of drive housing206. The rotary support structure218is at least co-rotatably connected to the shaft216, and mounted thereon.

The rotary support structure218has an interior region220configured to receive the electric motor204therein. The rotary support structure218includes a slanted section having an angled surface222. The slanted section of the rotary support structure218can be inscribed within a cylinder that has been truncated at an angle of 45° (relative to second axis210) and defining the angled surface222. The mirror202is supported on the angled surface222. The mirror202may be attached, for example, by glue, adhesive, optical bonding, mechanical clamps, mechanical fasteners (e.g., screws), or otherwise affixed to the angled surface222. As shown, a faceplate224is attached to rotary support structure218, overlapping an edge of the mirror202and defining a recess226.

An angular position sensor228is arranged on an end of the shaft216to enable monitoring angular position of the shaft216. Between the bearings212,214is the electric motor204, which may include stator and rotor elements. For example, a stator element may be arranged to drive rotation of rotor elements that are connected to or part of the shaft216to rotate the shaft216and/or the support structure218, and thus rotate the mirror202. Despite the asymmetrical shape, the rotary support structure218together with other components including the mirror202, is at least approximately (perpetually) balanced.

As shown inFIG. 2, the mirror assembly200is physically supported on one side, allowing for the mirror202to be mounted and positioned relative to a light source and thus enable scanning. To obtain accurate scans, the balancing of the mirror assembly is important. For example, during rotation of the mirror assembly200, the forces of the system may result in instability and/or loss of the mirror202. Accordingly, improved mirror assemblies for 3D scanners may be desirable.

Embodiments of the present disclosure are directed to mirrors and mirror assemblies for 3D scanners, and in some embodiments may be mirrors arranged within a cylindrical main body. The mirrors within a main body enable a robust and balanced mirror assembly for use with 3D scanners.

For example, turning now toFIGS. 3A-3B, schematic illustrations of an imaging device300in accordance with an embodiment of the present disclosure are shown.FIG. 3Ais an isometric illustration of the imaging device300having a mirror assembly302installed in a housing304.FIG. 3Bis an isometric illustration of the mirror assembly302as removed from the housing304and illustrating features thereof.FIG. 3Cis another isometric illustration of the mirror assembly302.

The housing304may be similar to that shown and described above with respect to the measuring head ofFIGS. 1A-1B. The housing304may include various components therein including, but not limited to, electronics, processors, control elements, power sources, bearings, light source(s), light receptors, etc. such as described above.

The mirror assembly302includes a main body306(e.g., a mirror rotor) and a mounting assembly308. Although shown inFIG. 3Awith a single mounting assembly308, a second mounting assembly310is positioned at an opposing end of the main body306, as shown inFIG. 3B). The main body306is mounted within the mounting assembly308,310and secured such that rotation of the mounting assembly308,310, or a portion thereof, enables rotation of the main body306.

The main body306is formed from a first portion306aand a second portion306bwhich define a main body when assembled, and in this example embodiment form a cylindrical main body. The first and second portions306a,306bare separate elements that, when joined, form the complete main body306. A mirror312is located between the first portion306aand the second portion306b. Although the term “mirror” is used herein, those of skill in the art will appreciate that the term, and elements referred to as a “mirror” may include any reflective surface, and is not limited to mirrors in the traditional sense.

At least one of the first portion306aand the second portion306bis optically transparent to allow for electromagnetic radiation (e.g., light) to pass therethrough. In some embodiments, both the first portion306aand the second portion306bare optically transparent, as described herein. The main body306, as shown inFIG. 3C, includes engagement surfaces314for engagement with the mounting assemblies308,310. The engagement surfaces314may be surfaces or edges of the material of the first and second portions306a,306bor may be a material or component applied or attached to the first and second portions306a,306b.

In one non-limiting embodiment, the main body306is a glass cylinder that is cut in half, at a 45° angle, as described below. The 45° cut separates the main body306into the first and second portions306a,306b. When separated, at least one of the first and second portions306a,306bis treated to form a mirror surface on the 45° surface thereof. Once applied, the first and second portions306a,306bare rejoined together to form the main body306having the mirror312therein. Thus, the arrangement inFIG. 3Cis assembled.

Once joined, the first and second mounting assemblies308,310can then be installed or attached such that the main body306is engaged between the first and second mounting assemblies308,310, as shown inFIG. 3B. The first and second mounting assemblies308,310include structure for engagement within the housing304. For example, a slotted engagement can be provided to insert the assembly mirror assembly302(shown inFIG. 3B) into the housing304. The mounting assemblies308,310, in some embodiments, may also provide a clamping force to ensure the first portion306aand the second portion306bare held together.

Further, as shown inFIGS. 3B-3C, at least one of the first portion306aand the second portion306binclude a window316. The window316is a flat surface of the respective first or second portion306a,306band arranged to allow electromagnetic radiation beams to pass therethrough without interfering therewith. The window316is an exterior surface cut face that is planar and parallel to the axis of rotation.

Thus, the window316is an exterior surface of the respective first or second portion306a,306bthat is arranged at a 45° angle relative to the mirror312. Accordingly, electromagnetic radiation beams can be transmitted from a source within the housing304, through an end surface318of the main body306, reflect off the mirror312, and exit through the window316. Any reflected light from an external object or surface may be reflected back through the window316, reflect off the mirror312, and through the end surface318of the main body306to a sensor or detector located within the housing304. Accordingly, the mirror assembly306can operate substantially similarly to the mirror assembly shown inFIG. 2, but may be more robust due to the construction and assembly within the housing304. For example, the main body306is a solid body and thus may be balanced easily without the need for complex balancing features within the housing, at a mounting assembly or support assembly, or associated with the mirror itself. Further, the main body306is engaged at both ends with the respective mounting assemblies308,310. Thus, physical support and engagement of the main body306is achieved at both ends providing additional support, stability, rigidity, and balance to the system.

In one non-limiting example, the main body (e.g., mirror rotor) is a cylindrical rotor made of glass. In some embodiments, the glass cylinder is cut into two pieces such that each piece has a cut face, e.g., forming angled cut faces. In some embodiments, the cut faces may be at of 45° although other angles may be employed without departing from the scope of the present disclosure. One or both of the pieces may be coated on the cut face to form or generate a mirrored or reflective surface. The two pieces may then be reassembled (e.g., glued) together to again form the cylinder. The formed cylinder is an axially symmetric body that may be nearly perfectly balanced.

In one embodiment, the two cut faces (e.g., the cut face of each portion) may be coated to achieve a specific function. For example, one of the two cut faces may be treated with a coating to reflect a laser beam and the other of the two cut faces may be treated with a coating to reflect visible light. The application of the coatings may be such that when the two portions are assembled to form the cylinder the reflective surfaces are facing in opposing directions. In such embodiment, two windows (e.g., window316shown inFIGS. 3B-3C) may be formed to allow for the passage of the respective electromagnetic radiation therethrough. Accordingly, the visible and laser light may be reflected in opposite directions as the main body rotates. To accommodate such arrangement, the housing or measuring head may be arranged with electromagnetic radiation sources on opposing sides thereof and arranged to project respective radiation toward the mirror rotated in between the sources. Respective electromagnetic radiation sensors would be arranged to receive the same reflected or returned electromagnetic radiation (or opposing electromagnetic radiation depending on the specific configuration). In alternative embodiments, a single cut face may be treated with a material or coating to reflect multiple different electromagnetic radiation beams (e.g., laser and visible).

In some embodiments, the coating may be a metallic coating applied to the cut faces. It is noted that current arrangements (e.g., as shown inFIG. 2) cannot employ metallic mirrors due to the mechanical resistance of such mirrors (as compared to current mirrors). However, such mirrors may be formed from silicon carbide materials, which may increase costs of such systems. In contrast, relatively low cost metallic mirrors may be used with the mirror assemblies of the present disclosure, thus reducing costs. In other embodiments, alternative coatings may be employed, including, but not limited to di-electric coatings.

In some embodiments, the faces or surfaces of the main body that have electromagnetic radiation beams pass therethrough may be treated to reduce, minimize or eliminate reflection, refraction, etc. Further, in embodiments where the main body forms a cylinder, the curved surfaces of the main body may be treated, coated, or covered with absorbing material to reduce or eliminate the effects of a cylindrical lens.

Turning now toFIG. 4, a cross-sectional illustration of a mirror assembly400in accordance with an embodiment of the present disclosure is shown. The mirror assembly400is similar to that shown and described above with respect toFIGS. 3A-3C, with a main body402engaged between a first mounting assembly404and a second mounting assembly406. The mirror assembly400is arranged to be mounted within a housing or measuring head and to be rotatably driven or spun, as described above.

The main body402includes a first portion408and a second portion410with a mirror412located therebetween. The first portion408is arranged to engage with the first mounting assembly404and the second portion410is arranged to engage with the second mounting assembly406. As shown, the first mounting assembly404includes a first support element414and a first bearing element416. Similarly, the second mounting assembly406includes a second support element418and a second bearing element420.

The support elements414,418are arranged to securely engaged with and hold the first and second portions408,410therebetween, and thus support the main body. The bearing elements416,420allow for rotation of the support elements414,418(and thus rotation of the main body402). One or both of the support elements414,418can be engaged by a motor assembly to drive rotation of the main body402.

Turning toFIG. 5, a schematic illustration of portion of an imaging device500in accordance with an embodiment of the present disclosure is shown. The imaging device500includes a housing502with a mirror assembly504installed therein. The mirror assembly504may be similar to the embodiments shown and described above. As such, the mirror assembly504includes a main body506having a first portion508and a second portion510with a mirror512located therebetween. The main body506is a cylindrical structure, such as shown and described above. The main body506is supported within the housing502by a first mounting assembly514at a first end and by a second mounting assembly516at a second end. The mirror512is angled at 45° and positioned on or between cut faces of the first and second portions508,510.

The first portion508includes a first engagement surface518that engages with a first support element520of the first mounting assembly514. A first bearing element522of the first mounting assembly514is arranged to provide movable engagement between the first mounting assembly514and the housing502. The second portion510includes a second engagement surface524that engages with a second support element526of the second mounting assembly516. A second bearing element528of the second mounting assembly516is arranged to provide movable engagement between the second mounting assembly516and the housing502.

A driving element530is arranged within the housing502and is configured to drive rotation of the main body506. As shown, the driving element530is engaged with the first support element520of the first mounting assembly514. The driving element530may be a motor, drive shaft, stator/rotor configuration, or have other arrangement as provided by those of skill in the art. In one non-limiting embodiment, the driving element530may be a frameless motor. Such a frameless motor may be mounted to the outer diameter521aof the first support element520. It should be appreciated that such an arrangement would allow the placement of a device, such as a camera or a light emitting device within the space defined by the inner diameter521bof the first support element520(or directly adjacent the opening). For example, in one non-limiting example, the secondary camera124, shown inFIG. 1A, may be positioned internally to receive light reflected off of the backside of mirror512.

Further, as shown, in the housing502and on the opposite side of the main body506from the driving element530is an electromagnetic radiation device532. The electromagnetic radiation device532is arranged to emit an emission beam534and also detect a returned reception beam536.

Although shown inFIG. 5with the driving element530and the electromagnetic radiation device532positioned on opposing sides, various other arrangements are possible without departing from the scope of the present disclosure. For example, each of the elements530,532shown inFIG. 5can include both a driving element and an electromagnetic radiation device, or one may comprise both a driving element and an electromagnetic radiation device and the other may comprise only an electromagnetic radiation device. In some such embodiments, two or more different electromagnetic radiation beams may be emitted and received to enable different types of scanning (e.g., distance by laser, and visible spectrum scan). Further, the mirror512shown inFIG. 5can include a dual-faced mirror with one mirror or reflective surface facing element532and the other mirror or reflective surface facing element530, thus enabling two or more different types of imaging. Accordingly, in some embodiments, one or more mirrors or reflective surfaces may be arranged between the first portion508and the second portion510.

Technical effects include scanning devices having a mirror that is securely installed within the device, with mounting on two sides thereof. For example, embodiments provided herein enable the placement of bearings on both ends of a main body or mirror rotor. Such arrangement enables low cost mirrors, installed between two portions of a main body (e.g., mirror rotor, cut cylinder, etc.). Further, such arrangement enables the use of multiple different scanning types (e.g., different wavelengths) by enabling customized mirrors and/or multiple mirrors (two-sided). The cut of the two portions is angled to prevent back reflection while optimizing reflection out of the device to interact with an external environment.

Surfaces of the main body may be arranged to be flat surfaces that are normal to the direction of incident radiation. Further, surfaces that are curved may be treated to minimize interference with the radiation that passes through the main body. The cylindrical shape of the main body of the present disclosure improves air resistance interactions as the mirror rotates.

In some embodiments, the mirror of the main body may be a thin film high dielectric coating, allowing for beam splitting.