Three-dimensional 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, 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 is known. 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, since light from a light source passes through a wavelength plate and reaches 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 according to the present disclosure acquires three-dimensional data of the surface shape of an object. The three-dimensional scanner includes a light source that irradiates light onto the object, an optical sensor that detects the light from the light source reflected by the object, a lens that is positioned between the object and the optical sensor and changes the focal position with respect to the object, a wavelength plate that is positioned between the object and the lens and through which the light directed at the object and the light reflected by the object pass, a main body that houses the light source, the optical sensor, and the lens, and a mounting portion that houses the wavelength plate and is mounted on the main body such that the wavelength plate is rotatable around the optical axis.

Effects of the Invention

[0007] According to the present disclosure, since the mounting portion that houses the wavelength plate is mounted on the main body such that the wavelength plate is rotatable around the optical axis, the user can easily adjust the position of the wavelength plate around the optical axis while it is mounted on the main body.

Brief Description of the Drawings

[0008]

Figure 1

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Figure 16

Embodiments for Carrying Out the Invention

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

[0010] [Configuration of the Three-Dimensional Scanner] With reference to FIG. 1, the three-dimensional scanner 1 according to the embodiment will be described. FIG. 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: Intra Oral Scanner) that scans the surface shape of an object 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 position information (coordinates of each axis in the vertical direction, horizontal direction, and height direction) of each point in a point cloud (a plurality of points) indicating the surface shape of the object. Note that the three-dimensional scanner 1 can also acquire color data indicating the color of each point in a point cloud (a plurality of points) indicating the surface shape of the object together with the three-dimensional data.

[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 is also applicable to other three-dimensional scanners having a similar configuration. For example, it is also applicable to a scanner that acquires three-dimensional data of the surface shape inside the outer ear by imaging the inside of a person's ear other than the inside of the mouth.

[0012] The user of the three-dimensional scanner 1 may be any person who acquires three-dimensional data of an object such as teeth and soft tissues using the three-dimensional scanner 1, such as a dental practitioner such as a dentist, a dental assistant, a teacher or student at a dental university, a dental technician, a manufacturer's technician, or an operator in a manufacturing factory. The subject to be scanned by the three-dimensional scanner 1 may be any person who can be the subject of scanning by the three-dimensional scanner 1, such as a patient in 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 a long 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 thereto 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 an object via the probe 20 on which the scanner chip 10 is mounted, and images the projected pattern. Note that the handpiece 2 is configured to acquire a three-dimensional shape using the principle of a focusing method as described below, but may also be configured to acquire a three-dimensional shape using other principles such as a confocal method or a triangulation method. That is, the handpiece 2 may be configured to use any principle as long as it is configured to acquire a three-dimensional shape using an optical method.

[0016] The control device 3 controls the operation of the handpiece 2 and processes the image 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 can also input information such as settings of the handpiece 2 using an input device (not shown).

[0017] Note that in the three-dimensional scanner 1 according to the embodiment, the control device 3 is configured separately from the handpiece 2, but if the control device 3 is small and lightweight enough to be lifted with one hand, part or all of the functions of the control device 3 may be mounted on the handpiece 2.

[0018] The display 5 displays the three-dimensional shape of the object indicated by the three-dimensional data obtained by the control device 3. The display 5 can also display other information such as setting information of the handpiece 2, patient information, startup status of the three-dimensional scanner 1, instruction manual, and help screen. For the display 5, for example, a stationary liquid crystal display, a head-mounted type, or a glasses-type wearable display can be applied. Note that the three-dimensional scanner 1 may include a plurality of displays 5, and the three-dimensional shape of the object and other information may be displayed on the plurality of displays 5 simultaneously or dividedly.

[0019] The power supply 4 supplies power to the handpiece 2 and the control device 3. The power supply 4 may be provided outside the control device 3, or may be provided inside the control device 3 or inside the handpiece 2. Note that the three-dimensional scanner 1 may include a plurality of power supplies 4 capable of supplying power to each of the handpiece 2, the control device 3, and the display 5.

[0020] In the example of FIG. 1, the handpiece 2, the control device 3, the power supply 4, and the display 5 of the three-dimensional scanner 1 are depicted as being wired by cables (thick lines in the figure), but a part or all of these wirings may be connected by wireless communication.

[0021] [Configuration of Handpiece] The handpiece 2 according to the embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram showing the internal configuration of the handpiece 2 according to the embodiment. FIG. 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 main body 30 of the handpiece 2 is defined as the X-axis, the axis along the depth direction of the main body 30 is defined as the Y-axis, and the axis along the height direction of the main body 30 is defined as the Z-axis. In FIG. 3, the X-Z cross-section of the handpiece 2 is shown.

[0022] As shown in FIGS. 2 and 3, the handpiece 2 includes an elongated main body 30, a probe 20 attached to the main body 30, and a scanner chip 10 detachably attached to the probe 20.

[0023] The handpiece 2 includes a light source 31, an optical sensor 32, a prism 33, a lens 34, and a counterweight 35 inside a handheld main body 30. Further, the handpiece 2 includes a wave plate 21 and at least one lens 22, 23 inside a probe 20 attached to the tip of the main body 30. In the examples of FIGS. 2 and 3, the handpiece 2 includes two lenses 22, 23 inside the probe 20, but it may include one lens or three or more lenses. The scanner chip 10 attached to the probe 20 includes a reflector 11 having a predetermined inclination at the tip.

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

[0025] The optical sensor 32 is composed of an imager and detects the light from the light source 31 reflected by the object.

[0026] The prism 33 is, for example, a polarizing beam splitter, is located between the light source 31 and the lens 34, and allows the light from the light source 31 to the object and the light reflected by the object to pass through. The prism 33 is an element for guiding the light of the two incident polarization components in different directions from each other.

[0027] The lens 34 is located between the object and the optical sensor 32 and changes the focal position with respect to the object.

[0028] The wave plate 21 is, for example, a quarter-wave plate, is located between the object and the lens 34, and allows the light to the object and the light reflected by the object to pass through. The wave plate 21 is an element that converts the state of the polarization components of the 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 as described above, the light from the light source 31 passes through the prism 33 and the lens 34, further passes through the probe 20, and is irradiated onto the object via the reflector 11 of the scanner chip 10. The light from the light source 31 reflected by the object passes through the probe 20 and the lens 34 again via the reflector 11 and enters the prism 33. Inside the probe 20, the wave plate 21 changes 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 the light of linearly polarized light Ez (for example, a wave that oscillates in the Z-axis direction) from the light source 31 is incident on the wave plate 21, which is a quarter-wave plate, a quarter-wave phase difference is added to the incident light to convert it into circularly polarized light, and the converted circularly polarized light is guided to the object via the reflector 11. On the other hand, when the light reflected by the object is incident again on the wave plate 21, the wave plate 21 adds a further quarter-wave phase difference to the incident light to convert the circularly polarized light into linearly polarized light Ey (for example, a wave that oscillates in the Y-axis direction), and the converted linearly polarized light Ey is guided to the prism 33 via at least one of the lenses 22, 23, 34. In this way, the light of linearly polarized light Ez from the light source 31 is converted into the light of linearly polarized light Ey by passing back and forth through the wave plate 21 and is guided to the prism 33.

[0030] When the light of linearly polarized light Ez from the light source 31 is incident on the prism 33, the prism 33 passes the incident linearly polarized light Ez along the X-axis direction and guides it to the lens 34. On the other hand, when the light of linearly polarized light Ey reflected by the object and converted by the wave plate 21 is incident on the prism 33, the prism 33 deflects the incident linearly polarized light Ey in the Z-axis direction and guides it to the optical sensor 32. The light deflected by the prism 33 is detected by the optical sensor 32. In the example shown in FIG. 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 easy understanding and explanation, and in reality, the handpiece 2 is configured such that the two lights are guided coaxially.

[0031] When acquiring a three-dimensional shape using the technology of the focusing method, light that has passed through a pattern generation element (not shown) provided between the lens 34 and the object is projected onto the object. When the lens 34 reciprocates linearly on the same straight line (for example, the optical axis L shown in FIG. 2), the focal position of the projection pattern changes. The optical sensor 32 detects light from the object at a predetermined frame rate for each change in the focal position of the projection pattern under the control of the control device 3, thereby imaging the object present at the focal position of the projection pattern. The control device 3 obtains three-dimensional data of the surface shape of the object by calculating 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.

[0032] Also, when the lens 34 reciprocates linearly in the direction of the optical axis L (X-axis direction), the center-of-gravity position of the handpiece 2 moves by the mass of the lens 34, and is transmitted as vibration to the hand of the user holding the handpiece 2. The counterweight 35 reciprocates linearly in the direction opposite to the lens 34, thereby canceling out the vibration generated by the reciprocating linear motion of the lens 34.

[0033] [Reflection of Light in a Waveplate or a Reflector] With reference to FIGS. 4 to 6, the reflection of light in the waveplate 21 or the reflector 11 will be described in detail. FIGS. 4 and 5 are diagrams for explaining the reflection of light in the waveplate 21. FIG. 6 is a diagram for explaining the reflection of light in the reflector 11.

[0034] In the example shown in FIG. 4, it is assumed that the wave plate 21 is arranged such that the surface of the wave plate 21 stands perpendicular (in the Z-axis direction) to the optical axis L without tilting the wave plate 21 from the optical axis L (X-axis). In this case, the linearly polarized light Ez from the light source 31 enters the wave plate 21, is reflected from the back surface of the wave plate 21, and is converted into linearly polarized light Ey by traveling back and forth within the wave plate 21. The linearly polarized light Ey reflected from the back surface of the wave plate 21 exits the wave plate 21 again along the optical axis L. The linearly polarized light Ey reflected from the back surface of the wave plate 21 and exiting the wave plate 21 is guided along the optical axis L to the prism 33, directionally changed by the prism 33 in the Z-axis direction, and then guided to the optical sensor 32. As a result, the optical sensor 32 detects the light reflected from the back surface of the wave plate 21 instead of the object.

[0035] To avoid false detection as shown in FIG. 4, as shown in FIG. 5, the wave plate 21 needs to be arranged to be inclined by a predetermined angle D from the optical axis L (X-axis). Specifically, the wave plate 21 needs to be inclined from the optical axis L such that the angle between the line perpendicular to the surface of the wave plate 21 and the optical axis L is the predetermined angle D. In this case, the linearly polarized light Ez from the light source 31 enters the wave plate 21, is reflected from the back surface of the wave plate 21, and is converted into linearly polarized light Ey by traveling back and forth within the wave plate 21. The linearly polarized light Ey reflected from the back surface of the wave plate 21 and exiting the wave plate 21 is guided in a direction inclined by a predetermined angle D from the optical axis L according to the predetermined angle D by which the wave plate 21 is inclined. Thus, since the linearly polarized light Ey reflected from the back surface of the wave plate 21 and exiting the wave plate 21 is guided in a direction where the prism 33 is not located, it is neither directionally changed by the prism 33 nor detected by the optical sensor 32. In this way, the wave plate 21 needs to be inclined from the optical axis L up to a predetermined angle D at which the light from the light source 31 reflected from the back surface of the wave plate 21 is not detected by the optical sensor 32. Note that the predetermined angle D by which the wave plate 21 is inclined may be any value as long as the light from the light source 31 reflected from the back surface of the wave plate 21 is not detected by the optical sensor 32.

[0036] Also, similar to the wave plate 21, the reflector 11 disposed in front of the wave plate 21 also needs to be inclined by a specific angle d from the optical axis L (X-axis). Specifically, the reflector 11 needs to be inclined from the optical axis L such that the angle between the line perpendicular to the surface of the reflector 11 and the optical axis L is the specific angle d. For example, as shown in FIG. 6, when the reflector 11 is inclined by a specific angle d from the optical axis L, the linearly polarized light Ez from the light source 31 passes through the wave plate 21, is reflected by the reflector 11, and passes through the wave plate 21 again, thereby being converted into linearly polarized light Ey. The linearly polarized light Ey reflected by the reflector 11 and emitted from the wave plate 21 is guided in a direction inclined by a specific angle d from the optical axis L according to the specific angle d at which the reflector 11 is inclined. In this way, since the linearly polarized light Ey reflected by the reflector 11 and emitted from the wave plate 21 is guided in a direction where the prism 33 is not located, it is neither deflected by the prism 33 nor detected by the optical sensor 32. In this way, the reflector 11 needs to be inclined from the optical axis L up to a specific angle d at which the light from the light source 31 reflected by the reflector 11 is not detected by the optical sensor 32. Note that the specific angle d at which the reflector 11 is inclined may 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. Also, the specific angle d at which the reflector 11 is inclined may be the same as or different from the predetermined angle D at which the wave plate 21 is inclined.

[0037] [Configuration of Probe] In the handpiece 2 of the three-dimensional scanner 1 configured as described above, in order for the light from the light source 31 to pass through the wave plate 21 and reach the object, it is necessary to rotate the wave plate 21 around the optical axis L to adjust the position of the wave plate 21. That is, the wave plate 21 needs to be rotatable around the optical axis L independently of the main body 30 in which the light source 31 is housed. Therefore, the handpiece 2 according to the embodiment is devised in the configuration of the probe 20 such that the wave plate 21 can be rotated around the optical axis L independently of the main body 30.

[0038] Referring to FIGS. 7 to 16, the mechanical configuration of the probe 20 according to the embodiment will be described. FIG. 7 is a diagram showing the mechanism of the probe 20 according to the embodiment. As shown in FIG. 7, the probe 20 includes a front portion 20A that houses the wave plate 21, and a rear portion 20B that is located behind the front portion 20A and houses the lenses 22 and 23. The rear portion 20B is fixedly attached to the main body 30. The front portion 20A is rotatably attached to the rear portion 20B around the optical axis L with the optical axis L as the central axis. As a result, the wave plate 21 housed in the front portion 20A is rotatably attached to the main body 30 around the optical axis L.

[0039] FIG. 8 is a diagram for explaining the adjustment of the mounting position of the wave plate 21 using the probe 20 according to the embodiment. The manufacturer of the handpiece 2 first attaches and fixes the rear portion 20B of the probe 20 to the main body 30, and then attaches the front portion 20A of the probe 20 to the rear portion 20B. As shown in FIG. 8, the manufacturer can easily adjust the position of the wave plate 21 around the optical axis L by rotating the front portion 20A around the optical axis L in a state where the front portion 20A is attached to the rear portion 20B.

[0040] As described above, when the probe 20 is divided into a front portion 20A in which the wave plate 21 is housed and a rear portion 20B attached to the main body 30, the wave plate 21 can rotate independently of the main body 30 around the optical axis L, but there is a risk that the front portion 20A may come off the rear portion 20B and fall into the oral cavity. For example, referring to FIGS. 9 to 11, the mechanism of the probe according to the comparative example will be described. FIGS. 9 to 11 are diagrams showing the mechanism of the probe according to the comparative example.

[0041] In the comparative example shown in FIG. 9, the front portion 20A is attached to the rear portion 20B by adhering the inner peripheral surface of the front portion 20A and the outer peripheral surface of the rear portion 20B with an adhesive 250A. In this case, once the front portion 20A is attached to the rear portion 20B, the wave plate 21 cannot be rotated around the optical axis L to adjust the position of the wave plate 21. Also, if the adhesive 250A peels off, there is a risk that the front portion 20A may come off the rear portion 20B and fall into the oral cavity.

[0042] In the comparative example shown in FIG. 10, the front portion 20A is attached to the rear portion 20B by fitting the inner peripheral surface of the front portion 20A and the outer peripheral surface of the rear portion 20B at the fitting portion 250B according to their shapes. In this case, although the possibility of the front portion 20A coming off from the rear portion 20B is small, the wavelength plate 21 cannot be fixed at that position in a state where the position of the wavelength plate 21 around the optical axis L is adjusted.

[0043] In the comparative example shown in FIG. 11, the front portion 20A is attached to the rear portion 20B by a screw 250C passing through the front portion 20A and the rear portion 20B. In this case, once the front portion 20A is attached to the rear portion 20B, the wavelength plate 21 cannot be rotated around the optical axis L to adjust the position of the wavelength plate 21. Further, when the screw 250C comes off, the front portion 20A may come off from the rear portion 20B and fall into the oral cavity together with the screw.

[0044] Therefore, as described below, in the handpiece 2 according to the embodiment, the configuration of the probe 20 is devised so that the wavelength plate 21 can rotate independently of the main body 30 around the optical axis L in a state of being attached to the main body 30.

[0045] FIGS. 12 and 13 are diagrams showing detailed portions of the mechanism of the probe 20 according to the embodiment. As shown in FIGS. 12 and 13, on the outer surface of the front portion 20A, a mountain-shaped first screw portion 210A protruding along the circumferential direction is formed. In this case, the outer surface of the front portion 20A corresponds to the "first surface". On the inner surface of the rear portion 20B, a mountain-shaped second screw portion 210B protruding along the circumferential direction is formed. In this case, the inner surface of the rear portion 20B corresponds to the "second surface". The first screw portion 210A formed on the outer surface of the front portion 20A fits into the second screw portion 210B formed on the inner surface of the rear portion 20B.

[0046] Furthermore, on the outer surface of the front portion 20A, a first space 220A is formed along the circumferential direction at a position adjacent to the first screw portion 210A. On the inner surface of the rear portion 20B, a second space 220B is formed along the circumferential direction at a position adjacent to the second screw portion 210B. In a state where the front portion 20A is attached to the rear portion 20B, the first screw portion 210A formed on the outer surface of the front portion 20A fits into and is housed in the second space 220B formed on the inner surface of the rear portion 20B. Also, in a state where the front portion 20A is attached to the rear portion 20B, the second screw portion 210B formed on the inner surface of the rear portion 20B fits into and is housed in the first space 220A formed on the outer surface of the front portion 20A.

[0047] On the outer surface of the front portion 20A, an inro 230A for attaching the front portion 20A to the rear portion 20B is formed. Similarly, on the inner surface of the rear portion 20B, an inro 230B for attaching the front portion 20A to the rear portion 20B is formed. For example, the inros 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 smoothly contacts the inner surface of the rear portion 20B and the front portion 20A can easily advance toward the rear portion 20B. Note that the inro 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. Also, the inro 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 FIGS. 14 to 16. FIGS. 14 to 16 are views showing the attachment of the front portion 20A to the rear portion 20B in the probe 20 according to the embodiment.

[0049] FIG. 14 shows the state of the probe 20 before the front part 20A is attached to the rear part 20B. Before the front part 20A is attached to the rear part 20B, an adhesive is applied to the surface portion of the front part 20A corresponding to the first space 220A and the surface portion of the rear part 20B corresponding to the second space 220B. The adhesive is not one that instantaneously adheres the front part 20A and the rear part 20B, but rather adheres the front part 20A and the rear part 20B after a predetermined time has elapsed. As shown in FIG. 14, the manufacturer attaches the front part 20A toward the rear part 20B while bringing the outer surface of the front part 20A into contact with the inner surface of the rear part 20B attached to the main body 30. Before the front part 20A is attached to the rear part 20B, the first screw portion 210A of the front part 20A and the second screw portion 210B of the rear part 20B are not yet engaged.

[0050] FIG. 15 shows the state of the probe 20 while the front part 20A is being attached to the rear part 20B. As shown in FIG. 15, when the manufacturer rotates the front part 20A around the optical axis L while engaging the first screw portion 210A of the front part 20A and the second screw portion 210B of the rear part 20B, the front part 20A advances toward the rear part 20B and gradually the front part 20A is attached to the rear part 20B. At this time, the outer surface of the front part 20A smoothly contacts the inner surface of the rear part 20B by the inro 230A formed on the outer surface of the front part 20A and the inro 230B formed on the inner surface of the rear part 20B, and the front part 20A advances toward the rear part 20B.

[0051] FIG. 16 shows the state of the probe 20 after the front part 20A is attached to the rear part 20B. As shown in FIG. 16, when the front part 20A advances toward the rear part 20B and the first threaded part 210A of the front part 20A exceeds the position of the second threaded part 210B of the rear part 20B, the first threaded part 210A of the front part 20A reaches the second space 220B of the rear part 20B and fits into and is stored in the second space 220B. In such a state, the first threaded part 210A of the front part 20A rotates freely around the optical axis L in the second space 220B of the rear part 20B. Also, the second threaded part 210B of the rear part 20B reaches the first space 220A of the front part 20A and fits into and is stored in the first space 220A. In such a state, the second threaded part 210B of the rear part 20B rotates freely around the optical axis L in the first space 220A of the front part 20A.

[0052] The manufacturer utilizes the free rotation around the optical axis L to rotate the front part 20A around the optical axis L in a state where the front part 20A is attached to the rear part 20B, thereby adjusting the position of the wave plate 21 around the optical axis L. At this time, even if an attempt is made to simply pull out the front part 20A in the direction opposite to the rear part 20B, the first threaded part 210A of the front part 20A is caught by the second threaded part 210B of the rear part 20B, so the front part 20A does not come off from the rear part 20B.

[0053] When a predetermined time elapses in a state where the front part 20A is rotationally adjusted around the optical axis L and set at a predetermined position, the adhesive applied to the portion of the surface corresponding to the first space 220A and the portion of the surface corresponding to the second space 220B of the rear part 20B hardens, and the front part 20A is fixed to the rear part 20B.

[0054] As described above, since the manufacturer can rotate the front portion 20A around the optical axis L with the front portion 20A attached to the rear portion 20B, the position of the wave plate 21 around the optical axis L can be easily adjusted. Further, since the first screw portion 210A of the front portion 20A is caught by the second screw portion 210B of the rear portion 20B, the front portion 20A is not easily detached from the rear portion 20B, so there is no risk that the front portion 20A detaches from the rear portion 20B and falls into the oral cavity. Also, even when the adhesive is peeled off, there is no risk that the front portion 20A detaches from the rear portion 20B and falls into the oral cavity.

[0055] <Modification Example> The handpiece 2 of the three-dimensional scanner 1 according to the present disclosure is not limited to the above-described embodiment, and various modifications and applications are further possible.

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

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

[0058] The handpiece 2 had an inlay 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 an inlay formed on either one of the outer surface of the front portion 20A and the inner surface of the rear portion 20B. That is, the handpiece 2 may have an inlay formed on at least one of the outer surface of the front portion 20A and the inner surface of the rear portion 20B.

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

[0060] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the above description, and it is intended that all modifications within the meaning and scope equivalent to the claims be included. Note that the configurations exemplified in the embodiments and the configurations exemplified in the modification examples can be combined as appropriate.

Explanation of Reference Numerals

[0061] 1 Three-dimensional scanner, 2 Handpiece, 3 Control device, 4 Power supply, 5 Display, 10 Scanner chip, 11 Reflector, 20 Probe, 20A Front portion, 20B Rear portion, 21 Wavelength plate, 22, 23, 34 Lens, 30 Main body, 31 Light source, 32 Optical sensor, 33 Prism, 35 Counterweight, 210A First screw portion, 210B Second screw portion, 220A First space, 220B Second space, 230A, 230B Inlay, 250A Adhesive, 250B Fitting portion, 250C Screw.

Claims

1. A three-dimensional scanner for acquiring three-dimensional data of the surface shape of an object, a light source that irradiates the object with light, an optical sensor that detects the light from the light source reflected by the object, a lens located between the object and the optical sensor, which changes the focal position with respect to the object, a wavelength plate located between the object and the lens, through which the light incident on the object and the light reflected by the object pass, a main body that houses the light source, the optical sensor, and the lens, and a mounting portion that houses the wavelength plate and is mounted on the main body such that the wavelength plate is rotatable around the optical axis. A three-dimensional scanner.

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

3. The mounting portion includes a front portion that houses the wavelength plate, and a rear portion that is located behind the front portion and is mounted on the main body, and the three-dimensional scanner according to claim 1 or claim 2, wherein the front portion is rotatably mounted on the rear portion around the optical axis.

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

5. On the first surface, after the first screw portion and the second screw portion are fitted and the front portion is mounted on the rear portion, a first space is formed for housing the second screw portion and allowing the front portion and the rear portion to rotate freely. On the second surface, after the first screw portion and the second screw portion are fitted and the front portion is attached to the rear portion, a second space is formed for accommodating the first screw portion so that the front portion and the rear portion rotate freely. The three-dimensional scanner according to claim 4.

6. With the front portion rotationally adjusted around the optical axis and set at a predetermined position, 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. The three-dimensional scanner according to claim 5.

7. On at least one of the first surface and the second surface, an inlay for attaching the front portion to the rear portion is formed. The three-dimensional scanner according to claim 4.

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