3D scanner

Abstract

To provide a technique capable of easily adjusting a position around an optical axis of a wavelength plate, with it mounted on a body.SOLUTION: A three-dimensional scanner 1 includes: a light source 31 for irradiating an object with light; an optical sensor 32 for detecting light from the light source 31 reflected by the object; a lens 34 located between the object and the optical sensor 32 and changing a focal position with respect to the object; a wave plate 21 located between the object and the lens 34, through which light to the object and light reflected by the object pass; a body 30 for storing the light source 31, the optical sensor 32 and the lens 34; and a mounting part for storing the wave plate 21, where the wave plate 21 is mounted on the body 30 so as to rotate around an optical axis.SELECTED DRAWING: Figure 12

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.

Background Art

[0002] Conventionally, there has been known a three-dimensional scanner that scans the surface shape of an object such as teeth and soft tissues in the oral cavity to acquire three-dimensional data of the surface shape. For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2023-86340) discloses a three-dimensional scanner including a handpiece in which a wavelength plate is attached to a main body that houses a light source, an optical sensor, and a lens.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a three-dimensional scanner, in order for light from a light source to pass through a wavelength plate and reach an object, it is necessary to rotate the wavelength plate around the optical axis to adjust the position of the wavelength plate. The three-dimensional scanner disclosed in Patent Document 1 is configured such that the wavelength plate is attached to the main body. However, once the wavelength plate is attached to the main body, it is difficult to rotate the wavelength plate around the optical axis to adjust the position of the wavelength plate.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a technique capable of easily adjusting the position of a wavelength plate around the optical axis in a state where the wavelength plate is attached to a main body.

Means for Solving the Problems

[0006] The three-dimensional scanner described herein acquires three-dimensional data of the surface shape of an object. The three-dimensional scanner comprises a light source that irradiates light onto the object, an optical sensor that detects light from the light source reflected by the object, a lens positioned between the object and the optical sensor that changes the focal position relative to the object, a waveplate positioned between the object and the lens through which light directed at the object and light reflected by the object pass, a main body that houses the light source, the optical sensor, and the lens, and a mounting part that houses the waveplate and is mounted on the main body so that the waveplate can rotate around the optical axis. [Effects of the Invention]

[0007] According to this disclosure, the mounting section for housing the waveplate is attached to the main body so that the waveplate can rotate around the optical axis, allowing the user to easily adjust the position of the waveplate around the optical axis while it is attached to the main body. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram shows the configuration of a three-dimensional scanner according to an embodiment. [Figure 2] This diagram shows the internal configuration of the handpiece according to the embodiment. [Figure 3] This figure shows a cross-section of a handpiece according to an embodiment. [Figure 4] This is a diagram illustrating the reflection of light in a waveplate. [Figure 5] This is a diagram illustrating the reflection of light in a waveplate. [Figure 6] This is a diagram illustrating the reflection of light on a reflector. [Figure 7] This diagram shows the mechanism of a probe according to an embodiment. [Figure 8] This is a diagram illustrating the adjustment of the mounting position of the waveplate using a probe according to the embodiment. [Figure 9] This figure shows the mechanism of a probe related to a comparative example. [Figure 10] This figure shows the mechanism of a probe related to a comparative example. [Figure 11] This figure shows the mechanism of a probe related to a comparative example. [Figure 12] This figure shows the detailed parts of the probe mechanism according to the embodiment. [Figure 13] This figure shows the detailed parts of the probe mechanism according to the embodiment. [Figure 14] This diagram shows the attachment of the front part to the rear part of the probe according to the embodiment. [Figure 15] This diagram shows the attachment of the front part to the rear part of the probe according to the embodiment. [Figure 16] This diagram shows the attachment of the front part to the rear part of the probe according to the embodiment. [Modes for carrying out the invention]

[0009] <Embodiment> Embodiments of this disclosure will be described with reference to the drawings.

[0010] [Configuration of a 3D scanner] The three-dimensional scanner 1 according to the embodiment will be described with reference to Figure 1. Figure 1 is a diagram showing the configuration of the three-dimensional scanner 1 according to the embodiment. The three-dimensional scanner 1 is an intraoral scanner (IOS) that scans the surface shape of objects such as teeth and soft tissues in the oral cavity and acquires three-dimensional data of the surface shape. The three-dimensional data includes the positional information (coordinates of each axis in the vertical, horizontal, and height directions) of each point cloud (multiple points) that represents the surface shape of the object. In addition to the three-dimensional data, the three-dimensional scanner 1 can also acquire color data indicating the color of each point cloud (multiple points) that represents the surface shape of the object.

[0011] The three-dimensional scanner 1 according to the embodiment is applicable not only to dentistry but also to the diagnosis and treatment of all medical fields such as ophthalmology, otolaryngology, radiology, internal medicine, surgery, and veterinary medicine. For example, the three-dimensional scanner 1 according to the embodiment is not limited to an intraoral scanner, but can also be applied to other three-dimensional scanners having a similar configuration. For example, it can also be applied to a scanner that obtains three-dimensional data of the surface shape inside the outer ear by imaging the inside of a person's ear other than the oral cavity.

[0012] The user of the three-dimensional scanner 1 may be anyone who uses the three-dimensional scanner 1 to obtain three-dimensional data of objects such as teeth and soft tissues, such as a dentist or other operator, a dental assistant, a teacher or student at a dental university, a dental technician, a manufacturer's technician, or a worker at a manufacturing factory. The subject to be scanned by the three-dimensional scanner 1 may be anyone who can be the subject of scanning by the three-dimensional scanner 1, such as a patient at a dental clinic or a subject at a dental university.

[0013] As shown in FIG. 1, the three-dimensional scanner 1 includes a handpiece 2, a control device 3, a power source 4, and a display 5. The handpiece 2 is a handheld member and includes an elongated main body 30, a probe 20 provided at the tip of the main body 30, and a scanner chip 10 detachably attached to the probe 20.

[0014] The probe 20 is an example of a "mounting portion". The probe 20 is attached to the main body 30 and has a shape that can be fitted to the base of the scanner chip 10. The probe 20 is inserted into the oral cavity with the scanner chip 10 attached, and projects light having a pattern (hereinafter also simply referred to as "pattern") onto an object such as teeth and soft tissues. The probe 20 receives the reflected light from the object onto which the pattern is projected and guides it to the main body 30. The scanner chip 10 covers the outer periphery of the probe 20 and is detachably attached to the probe 20.

[0015] The handpiece 2 projects a pattern onto the object via the probe 20 to which the scanner tip 10 is attached, and images the projected pattern. Although the handpiece 2 is configured to acquire the three-dimensional shape using the principle of the focusing method, as described below, it may also be configured to acquire the three-dimensional shape using other principles such as the confocal method or the trigonometric method. In other words, the handpiece 2 may have a configuration that uses any principle as long as it is configured to acquire the three-dimensional shape using an optical method.

[0016] The control device 3 controls the operation of the handpiece 2 and processes the images captured by the handpiece 2 to acquire a three-dimensional shape. The control device 3 can output three-dimensional data corresponding to the acquired three-dimensional shape to the display 5, and it is also possible to input information such as the settings of the handpiece 2 using an input device that is not shown.

[0017] In the three-dimensional scanner 1 according to this embodiment, the control device 3 is configured separately from the handpiece 2. However, if the control device 3 is small and lightweight enough to be lifted with one hand, some or all of the functions of the control device 3 may be incorporated into the handpiece 2.

[0018] Display 5 displays the three-dimensional shape of the object, as indicated by the three-dimensional data obtained by the control device 3. Display 5 can also display other information, such as the settings information of the handpiece 2, patient information, the startup status of the three-dimensional scanner 1, the instruction manual, and a help screen. Display 5 may be, for example, a stationary LCD display, a head-mounted display, or a glasses-type wearable display. The three-dimensional scanner 1 may be equipped with multiple displays 5, and the three-dimensional shape of the object and other information may be displayed simultaneously or in a split manner on multiple displays 5.

[0019] Power supply 4 supplies power to the handpiece 2 and the control device 3. Power supply 4 may be located outside the control device 3, or it may be located inside the control device 3 or inside the handpiece 2. The 3D scanner 1 may also be equipped with multiple power supplies 4 capable of supplying power to the handpiece 2, the control device 3, and the display 5, respectively.

[0020] In the example shown in Figure 1, the handpiece 2, control unit 3, power supply 4, and display 5 of the 3D scanner 1 are depicted as being wired together by cables (thick lines in the figure), but some or all of these connections may be made wirelessly.

[0021] [Handpiece Configuration] The handpiece 2 according to the embodiment will be described with reference to Figures 2 and 3. Figure 2 is a diagram showing the internal configuration of the handpiece 2 according to the embodiment. Figure 3 is a diagram showing a cross-section of the handpiece 2 according to the embodiment. In the following description, the axis along the width direction of the handpiece 2 body 30 will be referred to as the X-axis, the axis along the depth direction of the body 30 will be referred to as the Y-axis, and the axis along the height direction of the body 30 will be referred to as the Z-axis. Figure 3 shows the XZ cross-section of the handpiece 2.

[0022] As shown in Figures 2 and 3, the handpiece 2 comprises a long body 30, a probe 20 attached to the body 30, and a scanner tip 10 that is detachably attached to the probe 20.

[0023] The handpiece 2 comprises a light source 31, an optical sensor 32, a prism 33, a lens 34, and a counterweight 35 inside a handheld body 30. Furthermore, the handpiece 2 comprises a waveplate 21 and at least one lens 22, 23 inside a probe 20 attached to the tip of the body 30. In the examples in Figures 2 and 3, the handpiece 2 has two lenses 22, 23 inside the probe 20, but it may have one lens or three or more lenses. The scanner tip 10 attached to the probe 20 has a reflector 11 with a predetermined inclination at its tip.

[0024] The light source 31 consists of a laser element or LED (Light Emitting Diode) and a polarizer, and irradiates the object with light having a specific polarization component. In the example in Figure 2, the light emitted from the light source 31 passes through the handpiece 2 along the optical axis parallel to the X-axis.

[0025] The optical sensor 32 consists of an imager and detects light from the light source 31 that has been reflected off the object.

[0026] The prism 33 is, for example, a polarizing beam splitter, positioned between the light source 31 and the lens 34, allowing light from the light source 31 and light reflected by the object to pass through. The prism 33 is an element that guides the two incident polarized components of light in different directions.

[0027] The lens 34 is positioned between the object and the optical sensor 32, and changes the focal position relative to the object.

[0028] The waveplate 21 is, for example, a quarter-wave plate, positioned between the object and the lens 34, and allows light directed towards the object and light reflected by the object to pass through. The waveplate 21 is an element that transforms the state of the polarization components of incident light by adding a phase difference (optical path difference) to the two polarization components of the incident light.

[0029] In the handpiece 2 configured in this way, light from the light source 31 passes through the prism 33 and lens 34, then through the probe 20, and is irradiated onto the object via the reflector 11 of the scanner tip 10. The light from the light source 31 reflected by the object passes through the reflector 11 again, through the probe 20 and lens 34, and enters the prism 33. Within the probe 20, the waveplate 21 transforms the state of the polarization component of the light from the light source 31 by adding a phase difference to the polarization component of the light from the light source 31. For example, when linearly polarized Ez light (for example, a wave that oscillates in the Z-axis direction) is incident on the waveplate 21, which is a quarter-wave plate, it adds a phase difference of 1 / 4 wavelength to the incident light, converting it into circularly polarized light, and guides the converted circularly polarized light to the object via the reflector 11. On the other hand, when light reflected from the object is incident on the waveplate 21 again, it adds a phase difference of another quarter wavelength to the incident light, converting the circularly polarized light into linearly polarized light Ey (for example, a wave that oscillates in the Y-axis direction), and guides the converted linearly polarized light Ey to the prism 33 via at least one lens 22, 23, or 34. In this way, the linearly polarized light Ez from the light source 31 passes back and forth through the waveplate 21, is converted into linearly polarized light Ey, and is guided to the prism 33.

[0030] When linearly polarized Ez light is incident on the prism 33 from the light source 31, it guides the incident linearly polarized Ez light through in a straight line along the X-axis to the lens 34. On the other hand, when linearly polarized Ey light, which has been reflected by the object and converted by the waveplate 21, is incident on the prism 33, it redirects the incident linearly polarized Ey light in the Z-axis direction and guides it to the optical sensor 32. The light redirected by the prism 33 is detected by the optical sensor 32. In the example shown in Figure 3, the light from the light source 31 and the light reflected by the object and guided to the prism 33 are shown separately, but this is for illustrative purposes only; in reality, the handpiece 2 is configured so that both types of light are guided coaxially.

[0031] When acquiring a three-dimensional shape using the focusing technique, light passing through a pattern generation element (not shown) placed between the lens 34 and the object is projected onto the object. When the lens 34 moves back and forth along the same straight line (for example, the optical axis L shown in Figure 2), the focal position of the projected pattern changes. The optical sensor 32, in accordance with the control device 3, detects light from the object at a predetermined frame rate each time the focal position of the projected pattern changes, thereby imaging the object located at the focal position of the projected pattern. The control device 3 calculates the shape information of the object based on the position of the lens 34 and the detection result by the optical sensor 32 at that time, thereby acquiring three-dimensional data of the surface shape of the object.

[0032] Furthermore, when the lens 34 reciprocates linearly in the direction of the optical axis L (X-axis direction), the center of gravity of the handpiece 2 shifts by the mass of the lens 34, and this is transmitted as vibration to the user's hand holding the handpiece 2. The counterweight 35 cancels out the vibration caused by the reciprocating linear motion of the lens 34 by reciprocating linearly in a direction opposite to that of the lens 34.

[0033] [Reflection of light in a wave plate or reflector] The reflection of light in the waveplate 21 or the reflector 11 will be explained in detail with reference to Figures 4 to 6. Figures 4 and 5 are diagrams illustrating the reflection of light in the waveplate 21. Figure 6 is a diagram illustrating the reflection of light in the reflector 11.

[0034] In the example shown in Figure 4, we assume that the waveplate 21 is positioned so that its surface is perpendicular to the optical axis L (Z-axis direction) without tilting it from the optical axis L (X-axis). In this case, linearly polarized Ez light from the light source 31 enters the waveplate 21, is reflected on the back surface of the waveplate 21, and is converted into linearly polarized Ey light by traveling back and forth within the waveplate 21. The linearly polarized Ey light reflected from the back surface of the waveplate 21 is then emitted from the waveplate 21 again along the optical axis L. The linearly polarized Ey light reflected from the back surface of the waveplate 21 and emitted from the waveplate 21 is guided along the optical axis L to the prism 33, where it is redirected in the Z-axis direction and guided to the optical sensor 32. As a result, the optical sensor 32 detects the light reflected from the back surface of the waveplate 21, rather than the object itself.

[0035] To avoid false detections like those shown in Figure 4, the waveplate 21 needs to be positioned at a predetermined angle D from the optical axis L (X-axis), as shown in Figure 5. Specifically, the waveplate 21 needs to be tilted from the optical axis L such that the angle between a line perpendicular to the surface of the waveplate 21 and the optical axis L is a predetermined angle D. In this case, the linearly polarized Ez light from the light source 31 enters the waveplate 21, is reflected on the back surface of the waveplate 21, and is converted into linearly polarized Ey light by traveling back and forth within the waveplate 21. The linearly polarized Ey light reflected from the back surface of the waveplate 21 and emitted from the waveplate 21 is guided in a direction tilted by a predetermined angle D from the optical axis L, according to the predetermined angle D at which the waveplate 21 is tilted. In this way, the linearly polarized Ey light reflected from the back surface of the waveplate 21 and emitted from the waveplate 21 is guided in the direction where the prism 33 is not located, and is therefore neither redirected by the prism 33 nor detected by the optical sensor 32. Thus, the waveplate 21 needs to be tilted from the optical axis L to a predetermined angle D such that the light from the light source 31 reflected off the back surface of the waveplate 21 is not detected by the optical sensor 32. The predetermined angle D to which the waveplate 21 is tilted can be any value as long as the light from the light source 31 reflected off the back surface of the waveplate 21 is not detected by the optical sensor 32.

[0036] Furthermore, similar to the waveplate 21, the reflector 11, which is positioned in front of the waveplate 21, also needs to be positioned at a specific angle d from the optical axis L (X-axis). Specifically, the reflector 11 needs to be tilted from the optical axis L such that the angle between a line perpendicular to the surface of the reflector 11 and the optical axis L is a specific angle d. For example, as shown in Figure 6, when the reflector 11 is positioned at a specific angle d from the optical axis L, the linearly polarized Ez light from the light source 31 passes through the waveplate 21, is reflected by the reflector 11, and passes through the waveplate 21 again to be converted into linearly polarized Ey light. The linearly polarized Ey light reflected by the reflector 11 and emitted from the waveplate 21 is guided in a direction tilted by a specific angle d from the optical axis L, depending on the specific angle d of the reflector 11's tilt. In this way, the linearly polarized Ey light reflected by the reflector 11 and emitted from the waveplate 21 is guided in a direction where the prism 33 is not located, and therefore is not redirected by the prism 33 or detected by the optical sensor 32. Thus, the reflector 11 needs to be tilted from the optical axis L to a specific angle d such that the light from the light source 31 reflected by the reflector 11 is not detected by the optical sensor 32. The specific angle d to which the reflector 11 is tilted can be any value as long as the light from the light source 31 reflected by the reflector 11 is not detected by the optical sensor 32. Furthermore, the specific angle d to which the reflector 11 is tilted may be the same as or different from the predetermined angle D to which the wave plate 21 is tilted.

[0037] [Probe Configuration] In the handpiece 2 of the three-dimensional scanner 1 configured as described above, it is necessary to rotate the waveplate 21 around the optical axis L to adjust its position so that light from the light source 31 passes through the waveplate 21 and reaches the object. In other words, the waveplate 21 must be rotatable around the optical axis L independently of the main body 30 in which the light source 31 is housed. Therefore, in the handpiece 2 according to this embodiment, the probe 20 is configured in such a way that the waveplate 21 can rotate around the optical axis L independently of the main body 30.

[0038] The mechanical configuration of the probe 20 according to the embodiment will be described with reference to Figures 7 to 16. Figure 7 is a diagram showing the mechanism of the probe 20 according to the embodiment. As shown in Figure 7, the probe 20 includes a front section 20A that houses the waveplate 21 and a rear section 20B located behind the front section 20A that houses the lenses 22 and 23. The rear section 20B is fixedly mounted on the main body 30. The front section 20A is mounted on the rear section 20B so as to be rotatable around the optical axis L, with the optical axis L as the central axis. As a result, the waveplate 21 housed in the front section 20A is mounted on the main body 30 so as to be rotatable around the optical axis L.

[0039] Figure 8 is a diagram illustrating the adjustment of the mounting position of the waveplate 21 using the probe 20 according to the embodiment. The manufacturer of the handpiece 2 first attaches and fixes the rear part 20B of the probe 20 to the main body 30, and then attaches the front part 20A of the probe 20 to the rear part 20B. As shown in Figure 8, with the front part 20A attached to the rear part 20B, the manufacturer can easily adjust the position of the waveplate 21 around the optical axis L by rotating the front part 20A around the optical axis L.

[0040] As described above, when the probe 20 is divided into a front part 20A in which the waveplate 21 is housed and a rear part 20B attached to the main body 30, the waveplate 21 can rotate independently of the main body 30 around the optical axis L, but there is a risk that the front part 20A may detach from the rear part 20B and fall into the oral cavity. For example, the mechanism of the probe according to the comparative example will be explained with reference to Figures 9 to 11. Figures 9 to 11 are diagrams showing the mechanism of the probe according to the comparative example.

[0041] In the comparative example shown in Figure 9, the front part 20A is attached to the rear part 20B by bonding the inner surface of the front part 20A and the outer surface of the rear part 20B with adhesive 250A. In this case, once the front part 20A is attached to the rear part 20B, it is not possible to adjust the position of the waveplate 21 by rotating the waveplate 21 around the optical axis L. Also, if the adhesive 250A peels off, there is a risk that the front part 20A will detach from the rear part 20B and fall into the oral cavity.

[0042] In the comparative example shown in Figure 10, the front part 20A is attached to the rear part 20B by fitting together at the fitting part 250B, where the inner circumferential surface of the front part 20A and the outer circumferential surface of the rear part 20B are fitted together by their respective shapes. In this case, there is little risk of the front part 20A coming off the rear part 20B, but it is not possible to fix the waveplate 21 in the position after adjusting its position around the optical axis L.

[0043] In the comparative example shown in Figure 11, the front part 20A is attached to the rear part 20B by a screw 250C that passes through both the front part 20A and the rear part 20B. In this case, once the front part 20A is attached to the rear part 20B, it is not possible to adjust the position of the waveplate 21 by rotating the waveplate 21 around the optical axis L. Also, if the screw 250C comes loose, the front part 20A may detach from the rear part 20B and fall into the oral cavity along with the screw.

[0044] Therefore, as will be explained below, the handpiece 2 according to the embodiment is designed so that the waveplate 21 can rotate independently of the main body 30 around the optical axis L when attached to the main body 30, with modifications made to the configuration of the probe 20.

[0045] Figures 12 and 13 show detailed parts of the mechanism of the probe 20 according to the embodiment. As shown in Figures 12 and 13, a V-shaped first threaded portion 210A protruding in the circumferential direction is formed on the outer surface of the front portion 20A. In this case, the outer surface of the front portion 20A corresponds to the "first surface". A V-shaped second threaded portion 210B protruding in the circumferential direction is formed on the inner surface of the rear portion 20B. In this case, the inner surface of the rear portion 20B corresponds to the "second surface". The first threaded portion 210A formed on the outer surface of the front portion 20A fits into the second threaded portion 210B formed on the inner surface of the rear portion 20B.

[0046] Furthermore, a first space 220A is formed on the outer surface of the front portion 20A, adjacent to the first threaded portion 210A, along the circumferential direction. A second space 220B is formed on the inner surface of the rear portion 20B, adjacent to the second threaded portion 210B, along the circumferential direction. When the front portion 20A is attached to the rear portion 20B, the first threaded portion 210A formed on the outer surface of the front portion 20A is fitted into and housed in the second space 220B formed on the inner surface of the rear portion 20B. Also, when the front portion 20A is attached to the rear portion 20B, the second threaded portion 210B formed on the inner surface of the rear portion 20B is fitted into and housed in the first space 220A formed on the outer surface of the front portion 20A.

[0047] An interlocking joint 230A is formed on the outer surface of the front portion 20A for mounting the front portion 20A to the rear portion 20B. Similarly, an interlocking joint 230B is formed on the inner surface of the rear portion 20B for mounting the front portion 20A to the rear portion 20B. For example, the interlocking joints 230A and 230B are formed by shaping the outer surface of the front portion 20A and the inner surface of the rear portion 20B so that the outer surface of the front portion 20A can smoothly contact the inner surface of the rear portion 20B and the front portion 20A can easily move toward the rear portion 20B. The interlocking joint 230A may be provided on a part of the outer surface of the front portion 20A or on the entire outer surface of the front portion 20A. The interlocking joint 230B may be provided on a part of the inner surface of the rear portion 20B or on the entire inner surface of the rear portion 20B.

[0048] In the probe 20 configured as described above, the front portion 20A is attached to the rear portion 20B in the manner shown in Figures 14 to 16. Figures 14 to 16 show the attachment of the front portion 20A to the rear portion 20B in the probe 20 according to the embodiment.

[0049] Figure 14 shows the state of the probe 20 before the front section 20A is attached to the rear section 20B. Before the front section 20A is attached to the rear section 20B, adhesive is applied to the surface of the front section 20A corresponding to the first space 220A and the surface of the rear section 20B corresponding to the second space 220B. The adhesive does not instantly bond the front section 20A and the rear section 20B, but rather bonds them after a predetermined amount of time has elapsed. As shown in Figure 14, the manufacturer attaches the front section 20A toward the rear section 20B while bringing the outer surface of the front section 20A into contact with the inner surface of the rear section 20B which is attached to the main body 30. Before the front section 20A is attached to the rear section 20B, the first threaded portion 210A of the front section 20A and the second threaded portion 210B of the rear section 20B are not yet engaged.

[0050] Figure 15 shows the state of the probe 20 while the front section 20A is attached to the rear section 20B. As shown in Figure 15, when the manufacturer rotates the front section 20A around the optical axis L while engaging the first threaded portion 210A of the front section 20A with the second threaded portion 210B of the rear section 20B, the front section 20A advances toward the rear section 20B and gradually attaches to the rear section 20B. At this time, the front section 20A advances toward the rear section 20B while the outer surface of the front section 20A smoothly contacts the inner surface of the rear section 20B due to the spigot 230A formed on the outer surface of the front section 20A and the spigot 230B formed on the inner surface of the rear section 20B.

[0051] Figure 16 shows the state of the probe 20 after the front section 20A has been attached to the rear section 20B. As shown in Figure 16, the front section 20A moves toward the rear section 20B, and when the first threaded portion 210A of the front section 20A exceeds the position of the second threaded portion 210B of the rear section 20B, the first threaded portion 210A of the front section 20A reaches the second space 220B of the rear section 20B and is fitted into and stored in the second space 220B. In this state, the first threaded portion 210A of the front section 20A rotates freely around the optical axis L in the second space 220B of the rear section 20B. Also, the second threaded portion 210B of the rear section 20B reaches the first space 220A of the front section 20A and is fitted into and stored in the first space 220A. In this state, the second screw portion 210B of the rear portion 20B rotates freely around the optical axis L in the first space 220A of the front portion 20A.

[0052] The manufacturer uses free rotation around the optical axis L to adjust the position of the waveplate 21 around the optical axis L by rotating the front part 20A around the optical axis L while the front part 20A is attached to the rear part 20B. At this time, even if the manufacturer tries to simply remove the front part 20A in the opposite direction to the rear part 20B, the first threaded portion 210A of the front part 20A catches on the second threaded portion 210B of the rear part 20B, so the front part 20A does not come off the rear part 20B.

[0053] Once the front section 20A has been rotated and adjusted around the optical axis L and is in a predetermined position, a predetermined amount of time has elapsed. At this point, the adhesive applied to the surface corresponding to the first space 220A and the surface of the rear section 20B corresponding to the second space 220B hardens, and the front section 20A is fixed to the rear section 20B.

[0054] As described above, the manufacturer can easily adjust the position of the waveplate 21 around the optical axis L because the front part 20A can be rotated around the optical axis L while it is attached to the rear part 20B. Furthermore, since the first threaded portion 210A of the front part 20A catches on the second threaded portion 210B of the rear part 20B, the front part 20A does not easily detach from the rear part 20B, thus eliminating the risk of the front part 20A detaching from the rear part 20B and falling into the oral cavity. Also, even if the adhesive peels off, there is no risk of the front part 20A detaching from the rear part 20B and falling into the oral cavity.

[0055] <Variation> The handpiece 2 of the three-dimensional scanner 1 according to this disclosure is not limited to the above embodiment, and can be further modified and applied in various ways.

[0056] The handpiece 2 was configured such that the front part 20A was inserted inside the rear part 20B, and the front part 20A was mounted on the rear part 20B while the outer surface of the front part 20A was in contact with the inner surface of the rear part 20B. However, the handpiece 2 may also be configured such that the rear part 20B is inserted inside the front part 20A, and the front part 20A is mounted on the rear part 20B while the outer surface of the rear part 20B is in contact with the inner surface of the front part 20A. Furthermore, a first threaded portion 210A may be formed on the inner surface of the front part 20A, and a second threaded portion 210B may be formed on the outer surface of the rear part 20B. In this case, the inner surface of the front part 20A corresponds to the "first surface," and the outer surface of the rear part 20B corresponds to the "second surface."

[0057] Adhesive was applied to the portion of the front section 20A corresponding to the first space 220A and the portion of the rear section 20B corresponding to the second space 220B of the handpiece 2. However, adhesive may be applied to only one of the portions of the front section 20A corresponding to the first space 220A and the rear section 20B corresponding to the second space 220B of the handpiece 2. That is, adhesive may be applied to at least one of the portions of the front section 20A corresponding to the first space 220A and the rear section 20B corresponding to the second space 220B of the handpiece 2.

[0058] The handpiece 2 had a spigot formed on the outer surface of the front portion 20A and the inner surface of the rear portion 20B. However, the handpiece 2 may have a spigot formed on either the outer surface of the front portion 20A or the inner surface of the rear portion 20B. In other words, the handpiece 2 may have a spigot formed on at least one of the outer surface of the front portion 20A or the inner surface of the rear portion 20B.

[0059] In handpiece 2, the rear section 20B was separate from the main body 30, and the rear section 20B was configured to be fixedly attached to the main body 30. However, the rear section 20B may be formed integrally with the main body 30, for example, so as to be part of the main body 30. In this case, the front section 20A may be mounted on the rear section 20B, which is part of the main body 30, so as to be rotatable around the optical axis L.

[0060] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope of equivalence to the claims are intended to be included. The configurations illustrated in the embodiments and the configurations illustrated in the variations may be combined as appropriate. [Explanation of Symbols]

[0061] 1 3D scanner, 2 handpiece, 3 control unit, 4 power supply, 5 display, 10 scanner tip, 11 reflector, 20 probe, 20A front section, 20B rear section, 21 waveplate, 22, 23, 34 lenses, 30 main unit, 31 light source, 32 optical sensor, 33 prism, 35 counterweight, 210A first screw section, 210B second screw section, 220A first space, 220B second space, 230A, 230B spigot, 250A adhesive, 250B mating section, 250C screw.

Claims

1. A three-dimensional scanner that acquires three-dimensional data of the surface shape of an object, A light source that irradiates the aforementioned object with light, An optical sensor that detects light from the light source reflected by the object, A lens positioned between the object and the optical sensor, which changes the focal position relative to the object, A waveplate is positioned between the object and the lens, through which light directed to the object and light reflected by the object pass; The main body houses the light source, the optical sensor, and the lens, A three-dimensional scanner comprising a mounting section for housing the waveplate and for mounting the waveplate on the main body so as to be rotatable around the optical axis.

2. The three-dimensional scanner according to claim 1, wherein the waveplate is housed in the mounting portion such that a line perpendicular to the surface of the waveplate is inclined at a predetermined angle from the optical axis.

3. The aforementioned mounting portion is The front section housing the aforementioned waveplate, It includes a rear portion located behind the aforementioned front portion and attached to the main body, The three-dimensional scanner according to claim 1 or claim 2, wherein the front portion is mounted on the rear portion so as to be rotatable around the optical axis.

4. A first threaded portion is formed on the first surface of the inner or outer surface of the front portion. The three-dimensional scanner according to claim 3, wherein a second screw portion is formed on the inner or outer surface of the rear portion that contacts the first surface, and which engages with the first screw portion.

5. On the first surface, a first space is formed for the second screw portion to be housed and for the front portion to be mounted on the rear portion after the first screw portion and the second screw portion are fitted together, allowing the front portion and the rear portion to rotate freely. The three-dimensional scanner according to claim 4, wherein the second surface has a second space formed therein where the first screw portion is housed and the front portion is mounted on the rear portion after the first screw portion and the second screw portion are fitted together, allowing the front portion and the rear portion to rotate freely.

6. The three-dimensional scanner according to claim 5, wherein the front portion is fixed to the rear portion by an adhesive applied to at least one of the portion of the first surface corresponding to the first space and the portion of the second surface corresponding to the second space, while the front portion is rotated and adjusted around the optical axis to be set in a predetermined position.

7. The three-dimensional scanner according to claim 4, wherein at least one of the first surface and the second surface has a spigot formed thereon for mounting the front portion to the rear portion.

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