Three-dimensional scanner and control method

Abstract

To provide a technique of appropriately acquiring three-dimensional data of a surface shape of an object.SOLUTION: A three-dimensional scanner 100 includes: an imaging unit that images an object 99 at a focal position of a lens 81; a lens drive unit 80 that drives the lens 81 such that the lens 81 reciprocates in a linear direction; an angle detection unit that detects a change in an inclination angle with respect to a predetermined direction of the lens 81; and a lens control unit that controls operation of the lens 81 according to the change in the inclination angle detected by the angle detection unit.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a three-dimensional scanner that acquires three-dimensional data of the surface shape of an object by a focusing method, and a control method for controlling the three-dimensional scanner. [Background technology]

[0002] Conventionally, three-dimensional scanners are known that scan the surface shape of an object, such as teeth and soft tissues in the oral cavity, to obtain three-dimensional data of the surface shape. For example, Patent Document 1 (JP 2019-180881 A) discloses a three-dimensional scanner that obtains three-dimensional data of the surface shape of an object by projecting light that passes through the lens onto the object while moving the lens back and forth in a linear direction and detecting the light reflected by the object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-180881 Summary of the Invention [Problem to be solved by the invention]

[0004] The three-dimensional scanner disclosed in Patent Document 1 includes a handpiece that can be handheld by a user, such as a surgeon. During use, the handpiece is tilted at various angles. Therefore, as the tilt angle of the handpiece changes, the component of the direction of reciprocating motion of gravity acting on the lens in the handpiece changes, which can also change the center position of the lens's reciprocating motion. As a result, during use, the focal position of light passing through the lens may move away from or toward the tip of the handpiece, resulting in an unstable depth of field (the range of focal positions). Therefore, in order to align the focal position of the lens with the portion of the object being imaged, the user must move the handpiece closer or farther from the object depending on the tilt angle of the handpiece. Depending on the user's skill, this may prevent proper acquisition of three-dimensional data of the object's surface shape.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a technology that can appropriately acquire three-dimensional data of the surface shape of an object. [Means for solving the problem]

[0006] A three-dimensional scanner according to the present disclosure acquires three-dimensional data of the surface shape of an object using a focusing method, and includes a lens, an imaging unit that images an object at the focal position of the lens, a lens driving unit that drives the lens so that the lens moves back and forth in a linear direction, an angle detection unit that detects changes in the tilt angle of the lens relative to a predetermined direction, and a lens control unit that controls the operation of the lens in response to changes in the tilt angle detected by the angle detection unit.

[0007] A control method according to the present disclosure is a method for controlling a three-dimensional scanner that acquires three-dimensional data of the surface shape of an object using a focusing method. The control method includes, as processing executed by a computer, the steps of capturing an image of an object at a focal position of a lens provided in the three-dimensional scanner, driving the lens so that the lens moves back and forth in a linear direction, detecting a change in the tilt angle of the lens with respect to a predetermined direction, and controlling the operation of the lens in accordance with the change in the tilt angle detected in the detecting step. [Effects of the Invention]

[0008] According to the present disclosure, by detecting changes in the tilt angle of the lens relative to a predetermined direction and controlling the operation of the lens in accordance with the detected change in tilt angle, the focal position of the lens can be aligned with the object regardless of the tilt angle of the lens, thereby making it possible to properly obtain three-dimensional data of the surface shape of the object. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a three-dimensional scanner according to an embodiment. [Figure 2] 1A and 1B are diagrams illustrating a configuration of a handpiece according to an embodiment. [Figure 3] FIG. 2 is a diagram showing an XZ cross section of the handpiece according to the embodiment. [Figure 4] 10A and 10B are diagrams for explaining the positional relationship between a lens and a counterweight in the three-dimensional scanner according to the embodiment. [Figure 5] 2 is a view showing a YZ cross section of the linear motor according to the embodiment. FIG. [Figure 6] 2 is a diagram showing an XZ cross section of the linear motor according to the embodiment. FIG. [Figure 7] FIG. 10 is a diagram showing the depth of field according to the tilt angle of a handpiece according to a comparative example. [Figure 8] FIG. 2 is a diagram showing an encoder provided in the three-dimensional scanner according to the embodiment. [Figure 9]FIG. 2 is a diagram showing an encoder provided in the three-dimensional scanner according to the embodiment. [Figure 10] 10A and 10B are diagrams for explaining the reciprocating motion of the lens when the handpiece according to the embodiment is in a reference state. [Figure 11] 10A and 10B are diagrams for explaining the reciprocating motion of the lens when the handpiece according to the embodiment is in a reference state. [Figure 12] 10A and 10B are diagrams for explaining the reciprocating motion of the lens when the handpiece according to the embodiment is tilted vertically from a reference state. [Figure 13] 10A and 10B are diagrams for explaining the reciprocating motion of the lens when the handpiece according to the embodiment is tilted vertically from a reference state. [Figure 14] 10A and 10B are diagrams for explaining amplitude control executed when the handpiece according to the embodiment is tilted vertically from a reference state. [Figure 15] 10A and 10B are diagrams for explaining amplitude control executed when the handpiece according to the embodiment is tilted vertically from a reference state. [Figure 16] 10A and 10B are diagrams showing the position of the depth of field according to the tilt angle of the lens when amplitude control is performed in the three-dimensional scanner according to the embodiment. [Figure 17] 10A and 10B are diagrams for explaining control of a frame rate according to a tilt angle in a three-dimensional scanner according to an embodiment. [Figure 18] 10 is a flowchart of amplitude control executed by a control device in the three-dimensional scanner according to the embodiment. [Figure 19] FIG. 10 is a diagram for explaining a three-dimensional scanner according to a modified example. [Figure 20] FIG. 10 is a diagram for explaining a three-dimensional scanner according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Embodiment> Embodiments of the present disclosure will be described with reference to the drawings.

[0011] [Configuration of 3D scanner] FIG. 1 is a diagram showing the configuration of a three-dimensional scanner 100 according to an embodiment. The three-dimensional scanner 100 is an intraoral scanner (IOS) that scans the surface shape of an object 99, such as teeth and soft tissues in the oral cavity, and acquires three-dimensional data of the surface shape. The three-dimensional data includes position information (coordinates of each axis in the vertical, horizontal, and height directions) of each of a point cloud (multiple points) that indicates the surface shape of the object 99. The three-dimensional scanner 100 can also acquire color data that indicates the color of each of the point cloud (multiple points) that indicates the surface shape of the object 99, along with the three-dimensional data.

[0012] The three-dimensional scanner 100 according to the embodiment is applicable not only to dentistry but also to all medical fields such as ophthalmology, otolaryngology, radiology, internal medicine, surgery, and veterinary medicine. For example, the three-dimensional scanner 100 according to the embodiment is not limited to intraoral scanners, but can also be applied to other three-dimensional scanners having a similar configuration, such as a scanner that acquires three-dimensional data of the surface shape of the outer ear by imaging the inside of a human ear in addition to the inside of the oral cavity.

[0013] The user of the three-dimensional scanner 100 may be any person who acquires three-dimensional data of an object 99 such as teeth and soft tissue using the three-dimensional scanner 100, such as a dentist or other practitioner, a dental assistant, a professor or student at a dental school, a dental technician, a manufacturer's engineer, or a worker at a manufacturing plant. The person to be scanned by the three-dimensional scanner 100 may be anyone who can be scanned by the three-dimensional scanner 100, such as a patient at a dental clinic or a subject at a dental school.

[0014] 1, the three-dimensional scanner 100 includes a handpiece 70, a control device 40, a display 50, and a power supply 45. The handpiece 70 is a handheld member and includes a probe 10, a connection portion 20, and an optical measurement portion 30.

[0015] The probe 10 is inserted into the oral cavity and projects light having a pattern (hereinafter also simply referred to as "pattern") onto an object 99 such as teeth and soft tissue. The probe 10 guides the light reflected from the object 99 onto which the pattern is projected to the optical measurement unit 30. The probe 10 covers the outer periphery of the tip of the connection part 20 and is detachably attached to the connection part 20.

[0016] The connection part 20 is a part of the optical measurement part 30, protruding from the optical measurement part 30, and has a shape that can fit into the base of the probe 10. The connection part 20 includes optical components such as a lens system for guiding light collected by the probe 10 to the optical measurement part 30, a cover glass, an optical filter, and a retardation plate (for example, a quarter-wave plate).

[0017] The optical measurement unit 30 projects a pattern onto the object 99 via the probe 10 and captures an image of the projected pattern. Note that the optical measurement unit 30 according to the embodiment is configured to acquire a three-dimensional shape using the principle of the focusing method, as will be described below.

[0018] The control device 40 controls the operation of the optical measurement unit 30, and also acquires the three-dimensional shape by processing the images captured by the optical measurement unit 30. The control device 40 includes a calculation unit 41 and a storage unit .

[0019] The calculation unit 41 is a calculation entity (computer) that executes various programs to perform various processes. The calculation unit 41 is configured with a processor such as a CPU (central processing unit) or an MPU (micro-processing unit). A processor, which is an example of the calculation unit 41, has the function of executing various processes by executing programs. However, some or all of these functions may be implemented using dedicated hardware circuits such as an ASIC (application-specific integrated circuit) or an FPGA (field-programmable gate array). The term "processor" is not limited to a processor in the narrow sense that executes processes using stored programs, such as a CPU or an MPU, but may also include hardwired circuits such as an ASIC or an FPGA. Therefore, the "processor" as an example of the calculation unit 41 can also be interpreted as a processing circuitry whose processes are predefined by computer-readable code and / or hardwired circuits. The calculation unit 41 may be configured with one chip or multiple chips. Furthermore, the processor and related processing circuits may be configured with multiple computers interconnected by wire or wirelessly via a local area network or a wireless network. The processor and associated processing circuitry may be configured as a cloud computer that performs computations remotely based on input data and outputs the results of the computations to other devices at remote locations.

[0020] The storage unit 42 includes a memory and a storage device (not shown). The memory includes a volatile storage area (e.g., a working area) that temporarily stores program code or work memory when the calculation unit 41 executes various programs. Examples of the memory include volatile memories such as dynamic random access memory (DRAM) and static random access memory (SRAM), and non-volatile memories such as read-only memory (ROM) and flash memory. The storage device stores various programs and various data executed by the calculation unit 41. The storage device may be one or more non-transitory computer-readable media, or one or more computer-readable storage media. Examples of the storage device include hard disk drives (HDDs) and solid-state drives (SSDs).

[0021] In the three-dimensional scanner 100 according to the embodiment, the storage unit 42 stores a control program 43 executed by the calculation unit 41. By executing the control program 43, the calculation unit 41 performs processing related to amplitude control for controlling the reciprocating linear motion of the lens 81. Details of the amplitude control will be described later.

[0022] The control device 40 can also output the acquired three-dimensional data to the display 50, and can also input information such as settings for the optical measurement unit 30 using an input device (not shown).

[0023] In the three-dimensional scanner 100 according to the embodiment, the control device 40 is configured as a separate entity from the handpiece 70, but if the control device 40 is small and light enough to be lifted with one hand, some or all of the functions of the calculation unit 41 and memory unit 42 of the control device 40 may be incorporated into the handpiece 70.

[0024] In the example of Figure 1, each component (30, 40, 45, 50) of the three-dimensional scanner 100 is depicted as being wired by cables (thick lines in the figure), but some or all of these wires may be connected by wireless communication.

[0025] The display 50 displays the three-dimensional shape of the object 99 represented by the three-dimensional data obtained by the control device 40. The display 50 can also display other information, such as setting information for the optical measurement unit 30, patient information, the startup status of the scanner, an instruction manual, and a help screen. The display 50 may be, for example, a stationary liquid crystal display, a head-mounted or glasses-type wearable display, or the like. The three-dimensional scanner 100 may be equipped with multiple displays 50, and the three-dimensional shape of the object 99 and other information may be displayed simultaneously or in separate displays on the multiple displays 50.

[0026] The power supply 45 supplies power to the optical measurement unit 30 and the control device 40. The power supply 45 may be provided outside the control device 40 as shown in Fig. 1, or may be provided inside the control device 40 or inside the handpiece 70. Furthermore, a plurality of power supplies 45 may be provided so that power can be supplied individually to the control device 40, the optical measurement unit 30, and the display 50.

[0027] [Handpiece configuration] Fig. 2 is a diagram showing the configuration of a handpiece 70 according to an embodiment. Fig. 3 is a diagram showing an XZ cross section of the handpiece 70 according to an embodiment. Note that each member in the handpiece 70 shown in Figs. 2 and 3 is housed in the optical measurement unit 30 shown in Fig. 1.

[0028] 2 and 3, handpiece 70 includes a projection light generating unit 75, lens 81, optical sensor 71, and prism 72 inside a handheld housing 77. Optical sensor 71 is an example of an "imaging unit." Handpiece 70 may also include a reflector that reflects light toward object 99. For ease of explanation, in this embodiment, an imaginary line representing the direction in which lens 81 moves back and forth linearly is indicated by L, an axis parallel to line L is referred to as the X-axis, an axis perpendicular to line L and pointing upward on the paper surface in FIG. 2 is referred to as the Z-axis, and an axis perpendicular to both the X-axis and the Z-axis is referred to as the Y-axis.

[0029] The projection light generating unit 75 is a laser element or an LED (Light Emitting Diode) that serves as a light source. The light from the projection light generating unit 75 passes through a projection pattern screen (not shown) that generates a projection pattern and is disposed in front of the projection light generating unit 75, passes through the prism 72 and the lens 81, and is then irradiated onto the object 99 via a reflecting unit 66 provided on the probe 10 and reflected by the object 99. The light reflected by the object 99 passes through the lens 81 again via the reflecting unit 66 and enters the prism 72. The prism 72 changes the traveling direction of the light from the object 99 to the direction where the optical sensor 71 is located (in this example, the Z-axis direction). The light whose traveling direction has been changed by the prism 72 is detected by the optical sensor 71. In the example shown in FIG. 3, the light from the projection light generating unit 75 and the light reflected by the object 99 and directed to the prism 72 are shown separately, but this is for ease of explanation; in reality, the handpiece 70 is configured so that both beams of light are directed coaxially.

[0030] When acquiring a three-dimensional shape using the focusing technique, light passing through a pattern generating element (not shown) provided between the lens 81 and the object 99 is projected onto the object 99. When the lens 81 moves back and forth along the same straight line (e.g., line L in the figure), the focal position of the projection pattern changes. Under the control of the control device 40, the optical sensor 71 detects light from the object 99 at a predetermined frame rate each time the focal position of the projection pattern changes, thereby capturing an image of the object 99 located at the focal position of the projection pattern. The control device 40 can change the frame rate by changing the shutter speed of the optical sensor 71, and therefore functions as a "frame rate control unit." The control device 40 calculates shape information of the object 99 based on the position of the lens 81 and the detection result by the optical sensor 71 at that time, thereby acquiring three-dimensional data of the surface shape of the object 99.

[0031] Lens 81 is driven by lens driver 80 and moves linearly back and forth. When lens 81 moves linearly back and forth in the direction of line L (X-axis direction), the center of gravity of handpiece 70 moves by an amount equal to the mass of lens 81, and this is transmitted as vibration to the hand of the user holding handpiece 70. To cancel out this vibration, handpiece 70 further includes a counterweight 91 inside housing 77. Counterweight 91 is driven by counterweight driver 90 and moves linearly back and forth in a direction relative to lens 81.

[0032] The counterweight 91 is provided on the rear side of the projection light generating unit 75 in the X-axis direction so as not to block the optical path between the object 99 and the lens 81 and the optical path between the lens 81 and the optical sensor 71.

[0033] 3, handpiece 70 is provided with a first housing portion 501 located in front of handpiece 70 and a second housing portion 502 located in rear of handpiece 70 within housing 77. Lens 81 is accommodated in first housing portion 501, and counterweight 91 is accommodated in second housing portion 502. Handpiece 70 is further provided with a connecting housing portion 500 between first housing portion 501 and second housing portion 502, which connects lens 81 held by first housing portion 501 to counterweight 91 held by second housing portion 502. Connecting housing portion 500 accommodates optical sensor 71, prism 72, and projection light generator 75 described above.

[0034] Figure 4 is a diagram illustrating the positional relationship between lens 81 and counterweight 91 in three-dimensional scanner 100 according to an embodiment. Note that housing 77 is omitted in the example shown in Figure 4. As shown in Figure 4, lens 81 is supported by linear guide 60 parallel to line L so as to perform reciprocating linear motion in the direction of line L.

[0035] Furthermore, the lens driving unit 80 causes the lens 81 held by the mover to perform a linear reciprocating motion in the direction of the line L by means of a magnetic circuit configuration 85. In other words, the lens driving unit 80 is composed of a linear motor.

[0036] Counterweight 91 is a weight that is provided on line L in the linear motion direction of lens 81 and has the same mass as lens 81. Counterweight 91 is supported by linear guide 65 that is parallel to line L so as to move back and forth linearly in the direction of line L. In the embodiment, linear guide 60 and linear guide 65 are different members, but linear guide 60 and linear guide 65 may also be configured as a single continuous member.

[0037] Furthermore, the counterweight driving unit 90 causes the counterweight 91 held by the mover to perform a linear reciprocating motion in the direction of the line L by means of a magnetic circuit configuration 95. In other words, the counterweight driving unit 90 is composed of a linear motor.

[0038] The specific configurations of the lens driver 80 and counterweight driver 90, which are linear motors, will be described later. Hereinafter, the lens driver 80 and counterweight driver 90 will be collectively referred to simply as "linear motors." The lens driver 80 and counterweight driver 90 are each controlled by a control device 40. The control device 40 is an example of a "lens control unit" and a "counterweight control unit." In the embodiment, the lens driver 80 and the counterweight driver 90 are controlled by a common control device 40, but the lens driver 80 and the counterweight driver 90 may each be controlled by different control devices.

[0039] When the lens driving unit 80 causes the lens 81 to move back and forth in the direction of the straight line L that serves as the optical axis, the counterweight driving unit 90 causes the counterweight 91 to move back and forth in the direction opposite to the lens 81 by the same distance as the lens 81. For example, when the lens 81 moves 10 mm on the straight line L in a direction approaching the object 99, the counterweight 91 moves 10 mm on the straight line L in a direction away from the object 99. Furthermore, when the lens 81 moves 15 mm on the straight line L in a direction away from the object 99, the counterweight 91 moves 15 mm on the straight line L in a direction approaching the object 99.

[0040] In this way, the counterweight 91 moves linearly back and forth in the direction opposite to the lens 81 by the same distance as the lens 81, thereby offsetting the deviation of the center of gravity of the handpiece 70 caused by the linear reciprocating motion of the lens 81. As a result, the counterweight 91 can cancel out vibrations caused by the linear reciprocating motion of the lens 81.

[0041] [Linear motor configuration] Fig. 5 is a diagram showing a YZ cross section of a linear motor according to an embodiment. Fig. 6 is a diagram showing an XZ cross section of a linear motor according to an embodiment. In the example shown in Figs. 5 and 6, the configuration of the lens driving unit 80 of the linear motor will be described, but the configuration of the counterweight driving unit 90 is the same as that of the lens driving unit 80. That is, in the case of the counterweight driving unit 90, the lens 81 in the example shown in Figs. 5 and 6 is replaced with a counterweight 91, but the other configurations are the same as those of the lens driving unit 80.

[0042] 5 and 6, lens driving unit 80 has an elongated hollow shape along line L, which is the direction of linear motion, and each member for causing lens 81 to move back and forth linearly is arranged around lens 81 so that a substantially circular lens 81 can be provided in the center. In this way, since lens driving unit 80 is configured to have a substantially circular lens 81 in the center, light can pass through the center of lens driving unit 80.

[0043] 5, in lens driving unit 80, linear guide 60a composed of rail 57a and block 56a and linear guide 60b composed of rail 57b and block 56b are provided on the outer periphery of lens 81. In this way, the plurality of linear guides 60a, 60b are arranged at different positions on the outer periphery of lens 81.

[0044] More specifically, the multiple linear guides 60a, 60b are arranged parallel to each other at positions where they are rotationally symmetrical around the optical axis (straight line L) that is parallel to the linear motion direction of the lens 81 and passes through the center of the lens 81. For example, in FIG. 5, when the multiple linear guides 60a, 60b are each rotated 180 degrees around the line L as the rotation axis, the linear guide 60a is positioned at the position of the linear guide 60b, and the linear guide 60b is positioned at the position of the linear guide 60a. Although not shown in the figure, the multiple linear guides 65 are also arranged at similar positions. In other words, the multiple linear guides 65 are arranged parallel to each other at positions where they are rotationally symmetrical around the axis (straight line L) that is parallel to the linear motion direction of the counterweight 91 and passes through the center of the counterweight 91 as the rotation axis.

[0045] Block 56a of linear guide 60a supports lens 81 and is fitted into rail 57a, and moves linearly along rail 57a, causing reciprocating linear motion of lens 81. Block 56b of linear guide 60b supports lens 81 at a position different from block 56a and is fitted into rail 57b, and moves linearly along rail 57b, causing reciprocating linear motion of lens 81. Linear guides 60a and 60b correspond to linear guide 60 described with reference to FIG. 3.

[0046] 6, springs 55a and 55b serving as elastic members are provided along the outer periphery of lens 81 so as to surround the outer periphery of lens 81 and not to block the optical path at the center of lens 81. Coil springs or the like are used as springs 55a and 55b. Note that the elastic members are not limited to springs, and any member such as rubber that deforms when a force is applied and returns to its original shape when the force is released may be used.

[0047] One end of each of springs 55a and 55b abuts against lens 81, and the other end is fixed within housing 77. Furthermore, springs 55a and 55b are held within housing 77 so as to allow deformation in the X direction and to make deformation in the Y and Z directions difficult. Springs 55a and 55b arranged in this manner apply an elastic force to lens 81 in the linear motion direction. The diameters of springs 55a and 55b may be approximately the same as the diameter of lens 81 so that lens 81 can be sandwiched and fixed between the two springs.

[0048] A magnetic circuit configuration 85a is provided outside springs 55a and 55b (on the side away from the center of lens 81 in the Z direction) to cause lens 81 to move back and forth linearly in the direction of line L. Magnetic circuit configuration 85a includes magnet 53a consisting of an N pole and an S pole, and coil 52a arranged outside magnet 53a (on the side away from the center of lens 81 in the Z direction).

[0049] Magnet 53a is a mover that can move in the direction of straight line L, and when magnet 53a moves back and forth in the X direction along straight line L, lens 81 can also move back and forth in the X direction along straight line L. Coil 52a is a stator.

[0050] A yoke 51a is provided further outside the coil 52a (on the side farther away from the center of the lens 81 in the Z direction). The yoke 51a is a stator, similar to the coil 52a.

[0051] On the opposite side of the lens 81 from the magnetic circuit configuration 85a, there is provided a magnetic circuit configuration 85b for causing the lens 81 to move back and forth linearly in the direction of the line L. The magnetic circuit configuration 85b includes a magnet 53b having a north pole and a south pole, and a coil 52b arranged outside the magnet 53b (on the side away from the center of the lens 81 in the Z direction).

[0052] Magnet 53b is a mover that can move in the direction of straight line L, and when magnet 53b moves back and forth in the X direction along straight line L, lens 81 can also move back and forth in the X direction along straight line L. Coil 52b is a stator.

[0053] A yoke 51b is provided further outside the coil 52b. The yoke 51b is a stator, just like the coil 52b. Furthermore, the yokes 51a and 51b, which are stators, are appropriately fixed to the housing 77 of the handpiece 70.

[0054] In the lens driving section 80 having such a configuration, the magnetic circuit configuration 85a and the magnetic circuit configuration 85b apply a force to the lens 81 in the direction of the straight line L, causing the lens 81 to perform a linear reciprocating motion.

[0055] For example, in magnetic circuit configurations 85a and 85b, if magnets 53a and 53b, each consisting of a north pole and a south pole, are positioned as shown in Fig. 6, a magnetic field is generated in the direction of the dotted arrows. In this case, if a drive current (a current flowing from the front of the page to the back of the page along the Y axis is indicated by "x" and a current flowing from the back of the page to the front of the page along the Y axis is indicated by "·") is passed through coils 52a and 52b, respectively, an electromagnetic force (F) is generated in the X-axis direction as indicated by the solid arrow, in accordance with Fleming's left-hand rule. When the electromagnetic force (F) thus generated acts on magnets 53a and 53b, which are movers, magnets 53a and 53b, the magnets move in the direction opposite to the electromagnetic force (F). Hereinafter, the components involved in the movement of objects within the device, such as springs 55a, 55b, magnets 53a, 53b, lens 81, coils 52a, 52b, and dampers containing viscous lubricants such as grease, will also be referred to as the "movement system."

[0056] The lens 81 vibrates in the direction of line L due to the response of the motion system, including the inertial force of the lens 81, the electromagnetic force (F), the elastic force of the springs 55a and 55b, and the viscous force of the damper. The control device 40 utilizes this vibration to cause the lens 81 to perform linear reciprocating motion in the direction of line L. That is, the control device 40 controls the lens driver 80 at a constant cycle in accordance with the natural frequency of the motion system to pass drive currents to the magnetic circuit configurations 85a and 85b, thereby utilizing the resonance phenomenon of the motion system to cause the lens 81 to perform linear reciprocating motion in the direction of line L. Because the drive current is proportional to the amount of displacement in the reciprocating linear motion of the lens 81, the control device 40 can change the amount of displacement in the reciprocating linear motion of the lens 81 by changing the drive current. For example, the control device 40 can increase the amount of displacement in the reciprocating linear motion of the lens 81 by increasing the drive current, and decrease the drive current to decrease the amount of displacement in the reciprocating linear motion of the lens 81.

[0057] In this way, by passing a drive current through coils 52a and 52b in accordance with the natural frequency of the motor system, lens driver 80 can function as a resonant drive motor that reciprocates lens 81 in the direction of line L. Here, if the lens 81 is reciprocated linearly using a mechanical configuration in which a cam or other mechanical component is connected to a motor, the motor must be continuously driven while the lens 81 is moving. On the other hand, by utilizing the resonance phenomenon of the motor system as in the present embodiment, the lens 81 can be reciprocated linearly by simply passing a drive current through magnetic circuit configurations 85a and 85b at regular intervals. Therefore, using magnetic circuit configuration 85 as in the present embodiment reduces power consumption and is highly efficient. Furthermore, while a cam mechanism can generate contact noise and produce contact powder on the cam surface due to deterioration of the cam mechanism, these issues can be resolved by utilizing the resonance phenomenon of the motor system as in the present embodiment.

[0058] As described above, when the lens driver 80 causes the lens 81 to move back and forth along the line L, the counterweight driver 90 causes the counterweight 91 to move back and forth along the line L in a direction opposite to the lens 81 by the same distance as the lens 81. While the lens 81 moves back and forth along the line L, the counterweight 91 moves back and forth along the line L in a direction opposite to the direction of the linear movement of the lens 81 to offset the imbalance in the center of gravity. This allows the user to use the handpiece 70 without feeling any vibrations when holding it in their hand.

[0059] [Comparative Example] As described above, the three-dimensional scanner 100 is configured to change the focal position of light passing through the lens 81 by linearly reciprocating the lens 81 built into the handpiece 70, and to capture an image of the object 99 that is present at the focal position of the light. The focal position of the light that has passed through the lens 81 depends on the range of movement of the lens 81 that moves linearly back and forth.

[0060] Here, while the three-dimensional scanner 100 is in use, the handpiece 70 is tilted in various directions and angles. Therefore, the component of gravity acting on the lens 81 in the reciprocating direction (the direction of line L) changes depending on the tilt angle of the handpiece 70, i.e., the tilt angle of the lens 81 in the handpiece 70. For example, when the handpiece 70 is horizontal, the component of gravity acting on the lens 81 in the reciprocating direction is zero, but the more the tip of the handpiece 70 (tip of the probe 10) is tilted toward the vertical direction, the greater the component of gravity acting on the lens 81 in the reciprocating direction. When the tip of the handpiece 70 (tip of the probe 10) is pointing vertically, all of the gravity acting on the lens 81 is a component in the reciprocating direction.

[0061] In this way, when the component of gravity acting on lens 81 in the reciprocating motion direction changes in accordance with a change in the tilt angle of lens 81, the center position of the reciprocating motion of lens 81 may also change accordingly. For example, the more the tip of handpiece 70 is tilted vertically, the more the center position of the reciprocating motion of lens 81 moves toward the tip of handpiece 70. As a result, during use of the three-dimensional scanner 100, the focal position of light passing through lens 81 may move away from or towards the tip of handpiece 70, and the depth of field, which is the range of focal positions, may not be stable.

[0062] For example, Fig. 7 is a diagram showing the depth of field according to the tilt angle of handpiece 70 according to a comparative example. As shown in Fig. 7, it is assumed that the depth of field is designed with the reference state being a state in which handpiece 70 is tilted 45 degrees from the horizontal direction to the vertical direction.

[0063] When the handpiece 70 is in a horizontal position, the focal position of the lens 81 is farther from the tip of the handpiece 70 than when the handpiece 70 is tilted at 45 degrees. That is, the depth of field when the handpiece 70 is in a horizontal position is farther from the tip of the handpiece 70 than when the handpiece 70 is tilted at 45 degrees, which may result in a gap between the tip of the handpiece 70 and the depth of field. Therefore, when the handpiece 70 is in a horizontal position, the user needs to move the tip of the handpiece 70 farther from the object 99 than when the handpiece 70 is tilted at 45 degrees (the reference state) to scan the surface shape of the object 99 in order to align the focal position of the lens 81 with the portion of the object to be imaged. For example, when the handpiece 70 is in a horizontal position, the user needs to lift the tip of the handpiece 70 slightly above the object 99 to scan the surface shape of the object 99, which makes it difficult to move the handpiece 70 appropriately along the object 99.

[0064] When the handpiece 70 is tilted vertically, the focal position of the lens 81 is closer to the tip of the handpiece 70 than when the handpiece 70 is tilted 45 degrees. That is, the depth of field when the handpiece 70 is tilted vertically is closer to the tip of the handpiece 70 than when the handpiece 70 is tilted 45 degrees, so there is a risk that a part of the object 99 that the user is attempting to image (for example, the lower part of the object 99) will not be included in the depth of field. Therefore, when the handpiece 70 is tilted vertically, the user needs to scan the surface shape of the object 99 by moving the tip of the handpiece 70 closer to the object 99 than when the handpiece 70 is tilted 45 degrees (the reference state) in order to align the focal position of the lens 81 with the part of the object that the user is attempting to image. If the handpiece 70 is tilted at 45 degrees (standard state) and the user is scanning the object 99 while the tip of the handpiece 70 is in contact with the object 99, if the handpiece 70 is tilted vertically, the tip of the handpiece 70 cannot be brought any closer to the object 99, and therefore the surface shape of part of the object 99 (for example, the lower part of the object 99) cannot be imaged.

[0065] Thus, in order to align the focal position of lens 81 with the portion of object 99 to be imaged, the user needs to move handpiece 70 closer to or farther away from object 99 depending on the tilt angle of handpiece 70, and depending on the user's skill, there is a risk that 3D data of the surface shape of object 99 will not be properly acquired. Therefore, as will be described below, the 3D scanner 100 according to the embodiment is configured to align the focal position of lens 81 with object 99 regardless of the tilt angle of lens 81 by controlling the operation of lens 81 in accordance with changes in the tilt angle of handpiece 70, i.e., the tilt angle of lens 81.

[0066] [Detection of changes in tilt angle] Detection of a change in the tilt angle of the lens 81 by the control device 40 will be described with reference to Figures 8 to 13. Figures 8 and 9 are diagrams showing an encoder 82 provided in the three-dimensional scanner 100 according to this embodiment. The encoder 82 is a "position detection unit" for detecting the position of the lens 81, i.e., the focal position of the lens 81, and can also be used as an "angle detection unit" for the control device 40 to detect a change in the tilt angle of the handpiece 70 with respect to a predetermined direction by a method described below. In the three-dimensional scanner 100 according to this embodiment, a direction tilted 45 degrees from the horizontal to the vertical direction is applied as the predetermined direction, but the predetermined direction may also be determined in advance by the designer of the three-dimensional scanner 100, such as the horizontal direction.

[0067] 8 and 9 show an incremental encoder as an example of the encoder 82. The encoder 82 includes a detection unit 82A shown in Fig. 8 and a movement unit 82B shown in Fig. 9. The movement unit 82B includes a scale unit 82a and an index unit 82b.

[0068] Moving section 82B is supported at both ends by springs 55a and 55b together with lens 81. When lens 81 is in a horizontal position, index section 82b of moving section 82B reciprocates together with lens 81, centered on a predetermined encoder reference position. When lens 81 tilts from the horizontal position, the component of gravity acting on lens 81 in the direction of reciprocation changes, causing the center position of the reciprocation of index section 82b to move away from the encoder reference position.

[0069] The detector 82A detects the distance (the displacement of the lens 81) that the center position of the reciprocating motion of the index part 82b has moved away from the encoder reference position, using the scale part 82a as a clue. The controller 40 obtains the detection value of the scale part 82a and converts the obtained detection value into the tilt angle of the lens 81 with respect to a predetermined direction, thereby detecting a change in the tilt angle of the lens 81 with respect to the predetermined direction.

[0070] The "angle detection unit" is not limited to an incremental encoder, but may be an absolute encoder, a geomagnetic sensor, a gyro sensor, or a motion sensor such as an acceleration sensor.

[0071] 10 and 11, the reciprocating motion of lens 81 when handpiece 70 is in the reference state will be described. As shown in FIG. 7, the "reference state" is a state in which handpiece 70 (i.e., lens 81) is tilted 45 degrees from the horizontal to the vertical, but it may be in another state, such as a horizontal state. FIGS. 10 and 11 are diagrams for explaining the reciprocating motion of lens 81 when handpiece 70 according to the embodiment is in the reference state.

[0072] Fig. 10 shows a graph with time on the horizontal axis and the displacement amount of lens 81 on the vertical axis. Specifically, in the graph of Fig. 10, for each timing (t11 to t17) that arrives over time, the displacement amount of lens 81 when moved in a first direction (for example, to the right on the paper) is plotted on the positive side, and the displacement amount of lens 81 when moved in a second direction opposite to the first direction (for example, to the left on the paper) is plotted on the negative side.

[0073] For example, as shown in FIGS. 10 and 11, assume that the handpiece 70 is in the reference state and the lens 81 moves in a linear reciprocating motion. At t11, the lens 81 starts from the center of its reciprocating motion and moves in the first direction (to the right in the drawing). At t12, the lens 81 moves to its maximum in the first direction (to the right in the drawing). Thereafter, the elastic force of the spring 55a causes the lens 81 to return to the second direction (to the left in the drawing). At t13, the lens 81 passes the center of its reciprocating motion, and at t14, the lens 81 moves to its maximum in the second direction (to the left in the drawing). Thereafter, the elastic force of the spring 55b causes the lens 81 to return to the first direction (to the right in the drawing). At t15, the lens 81 passes the center of its reciprocating motion, and at t16, the lens 81 moves to its maximum in the first direction (to the right in the drawing). Thereafter, at t17, the elastic force of the spring 55a causes the lens 81 to return to the center of its reciprocating motion.

[0074] During the reciprocating motion of the lens 81 as described above, the encoder 82 detects that the index portion 82b is located at the encoder reference position and detects a change in the tilt angle of the lens 81 with respect to the predetermined direction. In the example of FIGS. 10 and 11, the encoder 82 detects that the index portion 82b is located at the encoder reference position at the timings (t11, t13, t15, t17) when the displacement amount of the lens 81 becomes zero, that is, when the lens 81 is located at the center position of the reciprocating motion. Therefore, the control device 40 can detect that the tilt angle of the lens 81 with respect to the predetermined direction is zero, that is, that the lens 81 is tilted 45 degrees from the horizontal to the vertical.

[0075] The reciprocating motion of lens 81 when handpiece 70 is tilted vertically from the reference state will be described with reference to Figures 12 and 13. Figures 12 and 13 are diagrams for explaining the reciprocating motion of lens 81 when handpiece 70 according to the embodiment is tilted vertically from the reference state.

[0076] Fig. 12 shows a graph with time on the horizontal axis and displacement of lens 81 on the vertical axis. Specifically, in the graph of Fig. 12, for each timing (t21 to t27) that arrives over time, the amount of displacement of lens 81 when moved in a first direction (right side of the paper) is plotted on the positive side, and the amount of displacement of lens 81 when moved in a second direction (left side of the paper) opposite to the first direction is plotted on the negative side.

[0077] For example, as shown in FIGS. 12 and 13, assume that the lens 81 moves and performs linear reciprocating motion while the handpiece 70 is tilted vertically from the reference state. At t21, the lens 81 starts from the center position of the reciprocating motion and moves in the first direction (to the right on the paper). At t22, the lens 81 passes the encoder reference position, and at t23, the lens 81 moves to its maximum in the first direction (to the right on the paper). Thereafter, the lens 81 returns to the second direction (to the left on the paper) due to the elastic force of the spring 55a. At t24, the lens 81 passes the encoder reference position, and at t25, the lens 81 passes the center position of the reciprocating motion. At t26, the lens 81 moves to its maximum in the second direction (to the left on the paper). Thereafter, the lens 81 returns to the first direction (to the right on the paper) due to the elastic force of the spring 55b. At t27, lens 81 passes the center position of its reciprocating motion, and further at t28, lens 81 passes the encoder reference position, and at t29, lens 81 moves to its maximum in the first direction (to the right on the paper). Thereafter, lens 81 returns in the second direction (to the left on the paper) due to the elastic force of spring 55a. At t30, lens 81 passes the encoder reference position, and at t31, lens 81 returns to the center position of its reciprocating motion.

[0078] During the reciprocating motion of the lens 81 as described above, the encoder 82 detects that the index portion 82b is located at the encoder reference position, and detects a change in the tilt angle of the lens 81 with respect to a predetermined direction. In the examples of FIGS. 12 and 13, the encoder 82 detects that the index portion 82b is located at the encoder reference position at the timings (t22, t24, t28, t30) when the displacement amount of the lens 81 reaches a predetermined amount. The control device 40 can detect a change in the tilt angle of the lens 81 with respect to the predetermined direction by converting the displacement amount of the lens 81 obtained from the encoder 82 into the tilt angle of the lens 81 with respect to the predetermined direction.

[0079] [Controlling lens movement according to tilt angle] 14 to 16, the control of lens 81 according to the tilt angle of lens 81 with respect to a predetermined direction will be described. Figures 14 and 15 are diagrams for explaining amplitude control that is executed when handpiece 70 according to the embodiment tilts vertically from the reference state.

[0080] 12 and 13, when the control device 40 detects a change in the tilt angle of the lens 81 with respect to a predetermined direction, the control device 40 changes the amplitude of the reciprocating motion of the lens 81 in accordance with the detected change in tilt angle. Specifically, as shown in FIGS. 14 and 15, the control device 40 increases the amplitude of the reciprocating motion of the lens 81 in accordance with the change in the tilt angle of the lens 81. The control device 40 can increase the amplitude of the reciprocating linear motion of the lens 81 by changing the drive current in accordance with the change in the tilt angle of the lens 81.

[0081] 14 shows a graph of the displacement amount of lens 81 versus time before amplitude control is performed, as well as a graph of the displacement amount of lens 81 versus time after amplitude control is performed. As shown in FIGS. 14 and 15, after amplitude control is performed, the displacement amount of lens 81 changes as follows:

[0082] At t41, the lens 81 starts from the center position of its reciprocating motion and moves in the first direction (to the right on the paper). At t42, the lens 81 passes the encoder reference position, and at t43, the lens 81 moves to its maximum in the first direction (to the right on the paper). At this time, the displacement amount of the lens 81 after amplitude control is greater than the displacement amount of the lens 81 before amplitude control. Thereafter, the elastic force of the spring 55a causes the lens 81 to return to the second direction (to the left on the paper). At t44, the lens 81 passes the encoder reference position, and at t45, the lens 81 passes the center position of its reciprocating motion, and at t46, the lens 81 moves to its maximum in the second direction (to the left on the paper). At this time, the displacement amount of the lens 81 after amplitude control is greater than the displacement amount of the lens 81 before amplitude control. Thereafter, the elastic force of the spring 55b causes the lens 81 to return to the first direction (to the right on the paper). At t47, lens 81 passes the center position of its reciprocating motion, and further at t48, lens 81 passes the encoder reference position, and at t49, lens 81 moves to its maximum in the first direction (to the right on the paper). At this time, the displacement amount of lens 81 after amplitude control is greater than the displacement amount of lens 81 before amplitude control. Thereafter, lens 81 returns in the second direction (to the left on the paper) due to the elastic force of spring 55a. At t50, lens 81 passes the encoder reference position, and at t51, lens 81 returns to the center position of its reciprocating motion.

[0083] 16 is a diagram showing the position of the depth of field according to the tilt angle of lens 81 when amplitude control is performed in three-dimensional scanner 100 according to the embodiment. As shown in FIG. 7, in the comparative example before amplitude control was performed, when handpiece 70 was in a horizontal position, the focal position of lens 81 was farther from the tip of handpiece 70 than when handpiece 70 was tilted at 45 degrees, resulting in a gap between the tip of handpiece 70 and the depth of field. In contrast, as shown in FIG. 16, after amplitude control was performed, the displacement of lens 81 was larger than before amplitude control, resulting in a larger depth of field than before amplitude control, and no gap was generated between the tip of handpiece 70 and the depth of field.

[0084] 7, in the comparative example before amplitude control was performed, when handpiece 70 was tilted vertically, the focal position of lens 81 was closer to the tip of handpiece 70 than when handpiece 70 was tilted 45 degrees, and a part of object 99 that the user was attempting to image (for example, the lower part of object 99) was not included in the depth of field. In contrast, as shown in FIG. 16, after amplitude control was performed, the displacement of lens 81 was larger than before amplitude control, and the depth of field was larger than before amplitude control, and the lower part of object 99 that the user was attempting to image can be included in the depth of field.

[0085] [Frame rate control according to tilt angle] Control of the frame rate according to the tilt angle of the lens 81 will be described with reference to Fig. 17. Fig. 17 is a diagram for explaining control of the frame rate according to the tilt angle in the three-dimensional scanner 100 according to the embodiment.

[0086] As described above, the control device 40 increases the amount of displacement in the reciprocating linear motion of the lens 81 by performing amplitude control in accordance with the tilt angle of the lens 81. Here, as the amount of displacement of the lens 81 increases, the imaging range of the optical sensor 71 increases. Therefore, in order to ensure the same level of measurement accuracy after the amplitude control as before the amplitude control, the control device 40 preferably controls the optical sensor 71 so that the frame rate is higher than before the amplitude control.

[0087] For example, as shown in FIG. 17, when the handpiece 70 is horizontal or tilted vertically, the amplitude of the lens 81 is larger than when the handpiece 70 is in the reference state in which it is tilted 45 degrees from horizontal to vertical, and therefore the control device 40 controls the optical sensor 71 to increase the frame rate accordingly.

[0088] As a result, even if the depth of field is increased by increasing the amplitude of the lens 81 through amplitude control, the three-dimensional scanner 100 can image the object 99 with the same resolution as before the amplitude control, thereby ensuring the same level of measurement accuracy as before the amplitude control.

[0089] [Control device processing flow] Fig. 18 is a flowchart of amplitude control executed by the control device 40 in the three-dimensional scanner 100 according to the embodiment. Each step (hereinafter, indicated by "S") shown in Fig. 18 is realized by the calculation unit 41 of the control device 40 executing the control program 43.

[0090] 18, the control device 40 drives the lens 81 so that the lens 81 moves linearly back and forth by supplying a drive current to the magnetic circuit configuration 85 (S1). The control device 40 determines whether the tilt angle of the handpiece 70, i.e., the tilt angle of the lens 81, has changed based on the detected value of the encoder 82 (S2).

[0091] If the tilt angle of the lens 81 has not changed (NO in S2), the control device 40 ends this processing flow. On the other hand, if the tilt angle of the lens 81 has changed (YES in S2), the control device 40 changes the amplitude of the reciprocating linear motion of the lens 81 by changing the drive current supplied to the magnetic circuit configuration 85 in accordance with the tilt angle of the lens 81 (S3). For example, as shown in FIGS. 14 to 16, the control device 40 increases the drive current supplied to the magnetic circuit configuration 85 in accordance with the tilt angle of the lens 81, thereby increasing the amplitude of the reciprocating linear motion of the lens 81.

[0092] When the control device 40 changes the amplitude of the reciprocating linear motion of the lens 81, it controls the optical sensor 71 to change the frame rate (S4). For example, as shown in Fig. 17, when the control device 40 increases the amplitude of the reciprocating linear motion of the lens 81, it controls the optical sensor 71 to increase the frame rate. Thereafter, this processing flow ends.

[0093] As described above, the three-dimensional scanner 100 according to the embodiment detects changes in the tilt angle of the lens 81 and controls the operation of the lens 81 in accordance with the detected change in tilt angle, thereby being able to align the focal position of the lens 81 with the object 99 regardless of the tilt angle of the lens 81, thereby making it possible to properly acquire three-dimensional data of the surface shape of the object 99.

[0094] Furthermore, regardless of the tilt angle of the lens 81, if the depth of field is increased, even when the depth of field is appropriate, such as in the reference state, the drive current increases, resulting in unnecessary consumption of drive current and increased heat generation. Furthermore, because the depth of field is increased even in the reference state, there is a possibility that unnecessary parts that are not the target of imaging will be captured, and the computational load required to remove the unnecessary parts increases, resulting in a corresponding slower computation speed and increased heat generation. However, in the three-dimensional scanner 100 according to the embodiment, the depth of field is changed in accordance with changes in the tilt angle of the lens 81, so that in the reference state, drive current is not wasted and unnecessary parts that are not the target of imaging are not captured.

[0095] <Modification> The present disclosure is not limited to the above-described examples, and various modifications and applications are possible. Modifications applicable to the present disclosure will be described below. Note that, in the three-dimensional scanner 100 according to the modification, only the parts that differ from the three-dimensional scanner 100 according to the embodiment will be described, and the same parts as those in the three-dimensional scanner 100 according to the embodiment will be assigned the same reference numerals and their description will not be repeated.

[0096] In the three-dimensional scanner 100 according to the embodiment, the control device 40 changes the amplitude of the reciprocating motion of the lens 81 by controlling the drive current in accordance with changes in the tilt angle of the lens 81, but the three-dimensional scanner 100 according to the modified example may be provided with a mechanism that changes the center position of the reciprocating motion of the lens 81 in accordance with changes in the tilt angle of the lens 81. More specifically, the three-dimensional scanner 100 according to the modified example may be provided with a mechanism that returns the center position of the reciprocating motion of the lens 81 to the position before the tilt angle of the lens 81 was changed in accordance with changes in the tilt angle of the lens 81.

[0097] 19 and 20 are diagrams illustrating a three-dimensional scanner 100 according to a modified example. As shown in FIG. 19, the weight of lens 81 is "m," the sum of the spring constants of springs 55a and 55b is "k," the tilt angle of lens 81 relative to a predetermined direction is "θ," and the amount of movement of lens 81 in the downward tilt direction is "X." Since the gravity of lens 81 is "F = mg," the downward component of gravity acting on lens 81 in the tilt direction is "F = mg sin θ." The force of springs 55a and 55b acting on lens 81 is "F = kX." Therefore, the amount of movement of lens 81 in the downward tilt direction is "X = mg sin θ / k."

[0098] In this way, the lens 81 moves downward in the tilt direction by an amount of "X = mg sin θ / k" according to the tilt angle of the lens 81. Therefore, as shown in Figure 20, in the three-dimensional scanner 100 according to the modified example, the handpiece 70 is provided with a movement mechanism 200, as an example of a "lens control unit", that moves the lens 81 upward in the tilt direction by an amount of "X = mg sin θ / k".

[0099] The movement mechanism 200 includes linear sliders 201 and 202, a disk 230, links 211 and 212, a spring 220, a support portion 240, and a balance weight 250. The linear slider 201 movably supports the lens driver 80. The linear slider 202 movably supports the counterweight driver 90. The link 211 connects the lens driver 80 and the disk 230. In this example, the disk 230 rotates counterclockwise as the link 211 moves downward in the tilt direction. The link 212 connects the counterweight driver 90 and the disk 230. In this example, the disk 230 rotates clockwise as the link 212 moves downward in the tilt direction. The balance weight 250 is connected to the disk 230 via the support portion 240.

[0100] According to the movement mechanism 200 configured as described above, the lens driver 80 and the counterweight driver 90 are balanced by the links 211, 212 and the disk 230, regardless of the tilt angle of the handpiece 70. Furthermore, since the lens driver 80 and the counterweight driver 90 are each provided with equal forces in opposing directions by the spring 220, the positional relationship between the lens driver 80 and the counterweight driver 90 is stable even when the handpiece 70 is in a horizontal position.

[0101] However, inside the lens driving unit 80, the lens 81 moves downward in the tilt direction by "X=mg sin θ / k", and therefore it is necessary to move the lens 81 upward in the tilt direction. In this regard, the weight of the balance weight 250 connected to the disk 230 via the support unit 240 causes the disk 230 to rotate clockwise, and the lens driving unit 80 moves upward in the tilt direction by "X=mg sin θ / k" together with the lens 81.

[0102] In this way, the three-dimensional scanner 100 according to the modified example can move the lens 81 upward in the tilt direction by "X = mg sin θ / k" in accordance with the change in the tilt angle of the lens 81, and therefore can return the center position of the reciprocating motion of the lens 81 to the position before the tilt angle of the lens 81 changed.

[0103] The medical diagnostic device to which the three-dimensional scanner 100 is applied may be a medical camera for taking images of the inside of the oral cavity, the inside of the outer ear, or digestive organs such as the stomach and intestines. In this case, the lens of the camera may be used as the object held by the mover of the linear motor, and a counterweight may be used as another mover.

[0104] Furthermore, a microscope may be used as a medical diagnostic device to which the three-dimensional scanner 100 is applied. In this case, a lens in the microscope may be used as an object held by a mover of a linear motor, and a counterweight may be used as another mover.

[0105] Furthermore, the medical diagnostic device to which the three-dimensional scanner 100 is applied may be a laser pointer that uses a laser beam to point to an object such as a diagram, or a laser device that cuts teeth. In this case, a lens may be applied as an object held by a mover of a linear motor, and a counterweight may be applied to another mover.

[0106] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. Note that the configurations exemplified in the embodiments and the configurations exemplified in the modified examples can be combined as appropriate. [Explanation of symbols]

[0107] 10 probe, 20 connection part, 30 optical measurement part, 40 control device, 41 calculation part, 42 memory part, 43 control program, 45 power supply, 50 display, 51a, 51b yoke, 52a, 52b coil, 53a, 53b magnet, 55a, 55b, 220 spring, 56a, 56b block, 57a, 57b rail, 60, 60a, 60b, 65 linear guide, 66 reflecting part, 70 handpiece, 71 optical sensor, 72 prism, 75 projection light generating part, 77 housing, 80 lens driving part, 81 lens, 82 encoder, 82A detection part, 82B moving part, 82a scale part, 82b index part, 85, 85a, 85b, 95 magnetic circuit configuration, 90 counterweight driving part, 91 Counterweight, 99 Object, 100 Three-dimensional scanner, 200 Moving mechanism, 201, 202 Linear slider, 211, 212 Link, 230 Disk, 240 Support part, 250 Balance weight, 500 Connecting storage part, 501 First storage part, 502 Second storage part.

Claims

1. A three-dimensional scanner that acquires three-dimensional data of the surface shape of an object by a focusing method, Lenses and an imaging unit that images the object at a focal position of the lens; a lens driving unit that drives the lens so that the lens moves back and forth in a linear direction; an angle detection unit that detects a change in the tilt angle of the lens with respect to a predetermined direction; a lens control unit that increases the amplitude of the reciprocating motion of the lens in response to a change in the tilt angle detected by the angle detection unit.

2. A three-dimensional scanner that acquires three-dimensional data of the surface shape of an object by a focusing method, Lenses and an imaging unit that images the object at a focal position of the lens; a lens driving unit that drives the lens so that the lens moves back and forth in a linear direction; an angle detection unit that detects a change in the tilt angle of the lens with respect to a predetermined direction; a lens control unit that returns the center position of the reciprocating motion of the lens to a position before the tilt angle changed in response to a change in the tilt angle detected by the angle detection unit.

3. The three-dimensional scanner according to claim 1 , wherein the imaging unit increases a frame rate at which the object is imaged in response to a change in the tilt angle.

4. The three-dimensional scanner according to any one of claims 1 to 3, wherein the angle detection unit is an incremental encoder or an absolute encoder.

5. a counterweight having a mass equal to or substantially equal to the mass of the lens; a counterweight driving unit that drives the counterweight so that the counterweight reciprocates in a direction relative to the lens; The three-dimensional scanner according to any one of claims 1 to 3, further comprising a counterweight control unit that controls the operation of the counterweight in accordance with the operation of the lens.

6. The three-dimensional scanner according to any one of claims 1 to 3, further comprising a handheld housing that houses the lens.

7. A control method for controlling a three-dimensional scanner that acquires three-dimensional data of a surface shape of an object by a focusing method, comprising: The process performed by the computer is capturing an image of the object at a focal position of a lens provided in the three-dimensional scanner; driving the lens so that the lens moves back and forth in a linear direction; detecting a change in the tilt angle of the lens relative to a predetermined direction; and increasing the amplitude of the reciprocating motion of the lens in response to a change in the tilt angle detected by the detecting step.

8. A control method for controlling a three-dimensional scanner that acquires three-dimensional data of a surface shape of an object by a focusing method, comprising: The process performed by the computer is capturing an image of the object at a focal position of a lens provided in the three-dimensional scanner; driving the lens so that the lens moves back and forth in a linear direction; detecting a change in the tilt angle of the lens relative to a predetermined direction; and returning a center position of the reciprocating movement of the lens to a position before the tilt angle changed in response to the change in the tilt angle detected in the detecting step.

Images