JP7484749B2 - Intraoral measurement device - Google Patents

Description

The present invention relates to an intraoral measurement device.

In recent years, the use of devices that measure the oral cavity in three dimensions has been increasing as an alternative to dental impressions. This reduces the pain experienced by patients and enables highly accurate digitalization compared to conventional silicone impressions.
However, when inserting a device into the patient's mouth for measurement, if the device is large, the patient must open their mouth wide, which is particularly burdensome for patients with symptoms such as a gag reflex. Therefore, making the device more compact is an important issue.

One measurement technique for constructing a compact device is to propagate the measurement light inside a prism and guide it to the part being measured (see, for example, Patent Documents 1 and 2).

US Patent Publication No. 2008/0024768 US Patent Publication No. 2008/0028065

When the measurement light is guided using a prism, it is desirable to totally reflect the measurement light on the prism surface (optical surface) in order to suppress loss of the amount of measurement light.
In addition, when attaching or detaching the prism from the housing, it is necessary to take care not to damage the optical surface of the prism, as a damaged optical surface may result in the desired optical performance not being achieved.

The present invention was made in consideration of the above circumstances, and aims to achieve suitable optical performance.

In order to achieve the above object, the present invention provides an intra-oral measurement device,
A prism having an optical surface;
A housing that houses the prism,
At least one of the prism and the housing has a guide portion that guides the relative movement during attachment and detachment,
the guide portion provides a gap between an optical surface of the prism and an inner surface of the housing when the prism is accommodated in the housing ,
The housing has a light-transmitting window through which measurement light passes,
The prism is
The housing is formed long along a direction in which the housing is attached to and detached from the housing.
The optical element further comprises a rib extending in a direction intersecting the attachment/detachment direction and extending upright on the optical surface .

The present invention allows for good optical performance.

1 is a perspective view of an intra-oral measurement device according to an embodiment. 1 is a cross-sectional view taken along the longitudinal direction of an intra-oral measurement device according to an embodiment. FIG. 2 is a perspective view of a prism according to the embodiment. FIG. 4A is a diagram for explaining a guide portion provided on a prism and a prism case, and FIG. 4B is a cross-sectional view showing a gap between an optical surface of the prism and the prism case. 13A and 13B are diagrams for explaining modified examples of the guide portion according to the embodiment. FIG. 13 is a perspective view of a modified example of the prism according to the embodiment. 13 is a cross-sectional view of a modified example of the intra-oral measurement device according to the embodiment. FIG.

The following describes an embodiment of the present invention with reference to the drawings.

[Overall configuration of intraoral measurement device]
FIG. 1 is a perspective view of an intra-oral measurement device 1 according to this embodiment, and FIG. 2 is a cross-sectional view taken along the longitudinal direction of the intra-oral measurement device 1. As shown in FIG.
In the following embodiments, the terms front, back, left, right, and up and down refer to the directions shown in the drawings. In addition, in Fig. 2, hatching of the prism 4 is omitted in order to make the light beams easier to see.

The intra-oral measurement device 1 is used mainly to measure the three-dimensional shape inside the oral cavity of a person (human body), and as shown in FIGS. 1 and 2, includes a prism case 2 and a device case 3.
The prism case 2 is open at the rear, and the device case 3 is open at the front. The prism case 2 and the device case 3 are fixed to each other so as to close each other's openings. The prism case 2 and the device case 3 house therein a measurement optical system 10 for three-dimensionally measuring the oral cavity.

The measurement optical system 10 includes a prism 4 housed in a prism case 2, and a projection device 31, a first lens 32, a second lens 33, and an image sensor 34 housed in an apparatus case 3. The projection device 31 includes, for example, an LED and a liquid crystal display element. The image sensor 34 is, for example, a CMOS sensor.
The measurement optical system 10 performs three-dimensional measurement using a phase shift method. Specifically, in the measurement optical system 10, light (measurement light) emitted from the projection device 31 enters the prism 4 from the rear surface through the first lens 32. This light is internally reflected by the optical surface of the prism 4 while being guided forward inside the prism 4, and is emitted downward from the lower surface of the front end of the prism 4, and is irradiated to a measurement object (e.g., a tooth) in the oral cavity through the light-transmitting window 20a at the front end of the prism case 2. At least a part of this irradiated light is reflected by the measurement object and enters the prism case 2 from the light-transmitting window 20a, and is internally reflected by the optical surface of the prism 4 while being guided backward inside the prism 4, and is emitted backward from the rear surface of the prism 4, and is then received by the image sensor 34 through the second lens 33. Then, based on the optical information of the received light, the shape of the measurement object is measured by an external control device (not shown).
The "optical surface" of the prism 4 refers to a surface that internally reflects (total reflects) the measurement light in the main optical path during the above measurement, and in this embodiment refers to an upper surface 41, a lower surface 42, and an inclined surface 44 described below. In addition, the specific configuration of the measurement optical system 10 is not particularly limited as long as it can optically three-dimensionally measure the intraoral cavity using the prism 4.

[Prism housing structure]
FIG. 3 is an oblique view of the prism 4, FIG. 4(a) is a diagram for explaining the guide portion provided on the prism 4 and the prism case 2, and FIG. 4(b) is a cross-sectional view showing the gap S between the optical surface of the prism 4 and the prism case 2.
As described above, the prism 4 is housed in the prism case 2 .
Specifically, the prism case 2 is made of a resin such as general-purpose engineering plastics or a metal, has a generally rectangular tubular shape that is long in the front-to-rear direction, and is formed with a generally uniform cross-sectional shape having an upper plate 21, a lower plate 22, and left and right side plates 23. At the front end of the prism case 2, an inclined plate 24 is formed whose upper surface is inclined downward toward the front, and whose front end is connected to the lower plate 22. At the rear end of the prism case 2, left and right side portions 25 protrude to the left and right, and the lower surface is inclined downward toward the rear.
On the other hand, as shown in Fig. 3, the prism 4 has a shape corresponding to the prism case 2, and is formed in a size slightly smaller so that it can be accommodated in the prism case 2. Specifically, the prism 4 is generally rod-shaped and long in the front-rear direction, and is formed in a generally uniform rectangular cross-sectional shape having an upper surface 41, a lower surface 42, and left and right side surfaces 43. At the front end of the prism 4, the upper surface forms an inclined surface 44 that is inclined downward toward the front, and is connected to the lower surface 42 at the front end. At the rear end of the prism 4, both left and right side portions 45 protrude to the left and right, and the lower surface is inclined downward toward the rear. Note that both side portions 45 at the rear end of the prism 4 do not have to protrude.

The prism 4 and the prism case 2 have guide portions (a guide protrusion 26 and a guide recess 46) that guide their relative movements when they are attached or detached.
4(a), the prism 4 is provided with guide recesses 46. The guide recesses 46 are provided at both corners between the upper surface 41 and both left and right side surfaces 43, and at both corners between the lower surface 42 and both left and right side surfaces 43. Each guide recess 46 is formed in a notch shape with an L-shaped cross section, and extends along the longitudinal direction (front-rear direction) of the prism 4.
Meanwhile, the prism case 2 is provided with guide protrusions 26 corresponding to the guide recesses 46 of the prism 4. The guide protrusions 26 are provided at each of the four inner corners of the prism case 2 corresponding to the positions of the four guide recesses 46 of the prism 4. Each guide protrusion 26 protrudes in an L-shape that fits into the corresponding guide recess 46, and extends along the longitudinal direction (front-rear direction) of the prism case 2.

These guide sections 46, 26 guide the relative movement of the prism 4 and prism case 2 in the attachment/detachment direction (front-to-back direction) when the prism 4 and prism case 2 are attached or detached. In other words, when attaching or detaching, the four corresponding guide recesses 46 and four guide protrusions 26 fit together, allowing the prism 4 to be appropriately inserted or removed from the prism case 2 along these guide sections 46, 26.

4B, when the prism 4 is accommodated in the prism case 2, the guide portions 46, 26 interpose a gap S between the optical surface of the prism 4 and the inner surface of the prism case 2. That is, when the prism 4 is accommodated in the prism case 2, the guide protrusions 26 and the guide recesses 46 come into contact with each other, so that the optical surfaces (upper surface 41, lower surface 42, and inclined surface 44) of the prism 4 do not come into contact with the prism case 2. Therefore, a gap S is formed between the optical surface of the prism 4 and the inner surface of the prism case 2. The size of the gap S may be equal to or larger than the wavelength of the measurement light of the measurement optical system 10. The gap S between the inclined surface 44 of the prism 4 and the inner surface of the prism case 2 facing the inclined surface 44 is formed by the guide protrusions 26 of the prism case 2 hitting the rear end surface of the guide recesses 46 of the prism 4. However, the gap S here may also be formed by providing guide protrusions 26 at both corners of the inclined plate 24 and both side plates 23 on the inner surface of the prism case 2, and bringing the guide protrusions 26 into contact with the side ends of the inclined surface 44 of the prism 4.
By forming such a gap S, the light propagating inside the prism 4 is internally reflected (total reflected) by the optical surface of the prism 4 itself. More specifically, since there is a gap S of an air layer with a smaller refractive index than the prism 4 between the optical surface of the prism 4 and the prism case 2, the light propagating inside the prism 4 is internally reflected (total reflected) by the surface (optical surface) of the prism 4 if the incident angle is equal to or greater than the critical angle. This makes it possible to suppress loss of the amount of light and to favorably propagate the measurement light, compared to when the optical surface of the prism 4 contacts the prism case 2.

The guide portions (guide structures) of the prism 4 and the prism case 2 are not limited to those described above. The guide portions guide the relative movements of the prism 4 and the prism case 2 when they are attached and detached, and may be configured to provide a gap between the optical surface of the prism 4 and the inner surface of the prism case 2 when the prism 4 is housed in the prism case 2.
As long as it is configured in this way, the positions and number of the guide parts are not particularly limited. For example, as shown in Fig. 5, guide protrusions 26 may be provided on both inner sides of prism 4, and corresponding guide recesses 46 may be provided on both side surfaces of prism case 2. However, when guide parts are provided on prism 4, it is preferable to provide them on a part of prism 4 that does not function as an optical surface, like guide recesses 46 in this embodiment. Also, when guide parts are provided on prism case 2, it is preferable to provide them on a part other than the part facing the optical surface of prism 4.
The shape of the guide portion is not particularly limited. However, when the guide portion is provided on the prism 4, it is preferable that the guide portion is formed in a convex shape with respect to the optical surface. This makes it possible to more reliably prevent the inner surface of the prism case 2 from contacting the optical surface of the prism 4.
Furthermore, the guide portion does not have to be provided on both the prism 4 and the prism case 2, but may be provided on at least one of the prism 4 and the prism case 2.

In addition, it is preferable that the guide portion provides a gap between the optical surface of the prism 4 and the inner surface of the prism case 2 when the prism 4 is attached to or detached from the prism case 2 (inserted or removed). This prevents the optical surface of the prism 4 from coming into contact with the prism case 2 and being damaged when the prism 4 is attached or detached. Note that this gap when the prism 4 is attached or detached may be different from the gap S when the prism 4 is stored. For example, to make it easier to insert the prism 4, the play (gap) between the guide portions may be large when the tip of the prism 4 is fitted into the opening of the prism case 2, and the play may be gradually reduced as the prism 4 is inserted.

As shown in FIG. 6, the prism 4 is preferably provided with a rib 47 extending in a direction perpendicular to the front-rear direction (i.e., the direction in which the prism 4 is attached and detached) on the optical surface. The extending direction of the rib 47 may be any direction intersecting with the front-rear direction. In the example of FIG. 6, the ribs 47 are provided at three locations on the upper surface 41, at the boundary between the upper surface 41 and the inclined surface 44, and at the boundary between the inclined surface 44 and the lower surface 42. Of these, the three locations on the upper surface 41, which is an optical surface, are preferably located as far away as possible from the total reflection position of the main optical path (see FIG. 2) on the upper surface 41. In the example of FIG. 6, the prism 4 is provided with a convex guide portion 46, which is connected to the rib 47.
By providing such ribs 47, even if the prism case 2 is bent, for example, by being grabbed by a user, the inner surface of the prism case 2 can be prevented from coming into contact with the optical surface of the prism 4.

[Technical Effects of the Embodiments]
As described above, according to this embodiment, at least one of the prism 4 and the prism case 2 has a guide portion (guide convex portion 26, guide concave portion 46) that guides their relative movement when attaching and detaching, and this guide portion creates a gap S between the optical surface of the prism 4 and the inner surface of the prism case 2 when the prism 4 is housed in the prism case 2.
This allows the measurement light to be suitably totally reflected on the surface of the prism 4. Therefore, loss of the amount of measurement light can be suppressed, and suitable optical performance can be obtained.
In addition, since the gap S during storage is secured by utilizing the guide portion during attachment and detachment, the prism 4 and the prism case 2 can be made compact compared with the case where a special portion is provided just for securing the gap S.

Furthermore, according to this embodiment, the guide portion provides a gap between the optical surface of the prism 4 and the inner surface of the prism case 2 when the prism 4 is attached to or detached from the prism case 2 .
This makes it possible to prevent the optical surface of the prism 4 from coming into contact with the prism case 2 and being damaged when the prism is attached or detached, and therefore makes it possible to more reliably obtain suitable optical performance.

Furthermore, according to this embodiment, the guide portion 46 is provided in a portion of the prism 4 that does not function as an optical surface.
Therefore, the guide portion 46 does not impede the optical function of the optical surface.

Furthermore, according to this embodiment, the guide portion 46 provided on the prism 4 may be formed in a convex shape with respect to the optical surface.
This makes it possible to more reliably prevent the inner surface of the prism case 2 from coming into contact with the optical surface of the prism 4 .

Furthermore, according to this embodiment, the optical surface of the prism 4 may be provided with a rib 47 extending in a direction intersecting the attachment/detachment direction.
This makes it possible to prevent the inner surface of the prism case 2 from coming into contact with the optical surface of the prism 4 even if the prism case 2 is bent, for example, by being grabbed by a user.

[others]
Although one embodiment of the present invention has been described above, embodiments to which the present invention can be applied are not limited to the above-described embodiment and its variations, and can be modified as appropriate without departing from the spirit of the present invention.

For example, as shown in FIG. 7, the prism 4 and the prism case 2 may be configured so that they are detachable into a prism 4A and a prism case 2A on the tip side and a prism 4B and a prism case 2B on the base side.
The tip of the intra-oral measurement device 1 is inserted into the patient's mouth, and is therefore sterilized after use. Sterilization usually requires exposure to an autoclave sterilization environment (134°C, 10 minutes). Therefore, by configuring the tip-side prism 4A and prism case 2A that are inserted into the oral cavity to be removable from the base-end side, only this part can be easily sterilized. Note that only the prism case 2 may be configured to be detachable between the tip-side prism case 2A and the base-side prism case 2B.

1 Intraoral measurement device 2 Prism case (housing)
26 Guide protrusion (guide portion)
4 Prism 41 Upper surface (optical surface)
42 Lower surface (optical surface)
43 Side surface 44 Inclined surface (optical surface)
46 Guide recess (guide portion)
47 Rib 10 Measurement optical system S Gap

Claims (8)

A prism having an optical surface;
A housing that houses the prism,
At least one of the prism and the housing has a guide portion that guides the relative movement during attachment and detachment,
the guide portion provides a gap between an optical surface of the prism and an inner surface of the housing when the prism is accommodated in the housing ,
The housing has a light-transmitting window through which measurement light passes,
The prism is
The housing is formed long along a direction in which the housing is attached to and detached from the housing.
a rib provided on the optical surface and extending in a direction intersecting the attachment/detachment direction;
An intraoral measurement device characterized by: the guide portion provides a gap between an optical surface of the prism and an inner surface of the housing when the prism is attached to or detached from the housing.
2. The intraoral measurement device according to claim 1 . The guide portion is provided on a portion of the prism that does not function as the optical surface.
3. The intraoral measurement device according to claim 1 or 2. The guide portion is provided on the prism and is formed in a convex shape with respect to the optical surface.
The intraoral measurement device according to any one of claims 1 to 3. an air layer is formed in a gap between the optical surface of the prism and the inner surface of the housing,
The optical surface of the prism internally reflects the measurement light.
The intraoral measurement device according to any one of claims 1 to 4. The intraoral measurement device measures the three-dimensional shape of the oral cavity.
The intraoral measurement device according to any one of claims 1 to 5. A prism having an optical surface;
A housing that houses the prism,
At least one of the prism and the housing has a guide portion that guides the relative movement during attachment and detachment,
the guide portion provides a gap between an optical surface of the prism and an inner surface of the housing when the prism is accommodated in the housing,
The housing has a light-transmitting window through which measurement light passes,
The guide portion is provided on a portion of the prism that does not function as the optical surface.
An intraoral measurement device characterized by: A prism having an optical surface;
A housing that houses the prism,
At least one of the prism and the housing has a guide portion that guides the relative movement during attachment and detachment,
the guide portion provides a gap between an optical surface of the prism and an inner surface of the housing when the prism is accommodated in the housing,
The housing has a light-transmitting window through which measurement light passes,
The guide portion is provided on the prism and is formed in a convex shape with respect to the optical surface.
An intraoral measurement device characterized by:

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