Patent Description:
For the today's digitized dental treatment, the digital impression is an important beginning stage. As the importance of digital impressions increases in the dental treatment, technical development of intraoral scanners is also actively achieved.

The intraoral scanner is a device or system that is inserted into the oral cavity of a patient and scans the 3D structure of teeth in a non-contact manner. The recently developed intraoral scanner can capture 2D image data of the oral cavity, and perform 3D modeling of the oral structure based on the 2D image data. The applications of the intraoral scanners having these functions have expanded to the clinical practices, and the intraoral scanner can be used not only for dental restoration treatment, but also for manufacturing of implants and orthodontic devices.

Meanwhile, the accuracy of the impression is important for successful dental treatment. The digital impressions captured through the intraoral scanner do have deformation due to contraction or expansion of impression materials, and thus have higher impression accuracy than the traditional impressions using the existing impression materials. Meanwhile, it is necessary to further improve the accuracy of scanning to use the intraoral scanner as a sophisticated dental treatment tool. In addition, since the intraoral scanner is used while being inserted in the oral cavity of the patient in a non-contact manner, it is desirable that the intraoral scanner preferably has a structure that allows the patient to feel comfortable while the intraoral scanner is in use.

<CIT> discloses an intraoral scanning device having an optical sub-system that generates light and have a return path that receives reflected light, and a tip portion having a mirror for projecting light towards the target area to be scanned and that receives imaging light reflected from the target area.

<CIT> discloses a three-dimensional oral scanner having a case which can be drawn in and out of an oral cavity and has an opening; a pair of lenses disposed inside the case and spaced apart from each other in the width direction of the case so as to pass light incident from one end of the case in different paths; a pair of imaging boards having an imaging sensor for imaging the respective lights transmitted through the pair of lenses and disposed in close contact with a widthwise side wall and the other widthwise side wall of the case; and a pair of light path changing units arranged to change the respective paths of the lights transmitted through the pair of lenses toward the imaging board.

<CIT> discloses an intra-oral measurement device provided with a light projecting unit for irradiating lights in at least two different wavelengths along an identical light axis toward an object to be measured that includes at least a tooth in an oral cavity, and an image pickup unit for receiving lights reflected on the object to be measured and picking up an image, so that an intra-oral shape can be accurately measured without spraying the metal powder within the oral cavity.

However, the above-mentioned issues are not overcome.

In order to solve one or more problems (e.g., the problems described above and/or other problems not explicitly described herein), the present disclosure provides an intraoral scanner including a plurality of optical systems disposed therein so as to achieve a structure suitable for insertion into and use in the oral cavity of a patient in a non-contact manner.

The intraoral scanner may include a case including an opening, a light source unit disposed in the case and configured to emit light, a first optical system reflecting the light emitted from the light source unit toward a subject and reflecting light reflected from the subject toward the light source unit, a second optical system disposed between the light source unit and the first optical system and reflecting light reflected from the first optical system, and an image sensor unit that detects the light reflected from the second optical system.

A gap may be formed in a center of the second optical system such that the light emitted from the light source unit may pass through the gap to reach the first optical system.

The second optical system may include a first reflector configured to reflect the light reflected from the first optical system, and a second reflector configured to reflect the light reflected by the first reflector toward the image sensor unit.

The first reflector may include two reflective surfaces configured such that a dihedral angle between each infinite plane forms a minor angle, and the second reflector may include two reflective surfaces configured such that a dihedral angle between each infinite plane forms a major angle.

Positions and directions of each of the two reflective surfaces of the second reflector may be set such that two images of the subject reflected by the two reflective surfaces of the second reflector and detected by the image sensor unit do not overlap with each other.

The second optical system may include a first prism and a second prism, the light emitted from the light source unit may pass through a gap formed between the first prism and the second prism to reach the first optical system, and the light reflected by the first optical system may be reflected by a pair of opposing reflective surfaces of the first prism and a pair of opposing reflective surfaces of the second prism to reach the image sensor unit.

A dihedral angle between an infinite plane of one reflective surface of the first prism and an infinite plane of one reflective surface of the second prism may form a minor angle, and a dihedral angle between an infinite plane of the other reflective surface of the first prism and an infinite plane of the other reflective surface of the second prism may form a major angle.

Positions and directions of the other reflective surface of the first prism and the other reflective surface of the second prism may be set such that two images of the subject reflected by the two other reflective surfaces and detected by the image sensor unit do not overlap with each other.

The light source unit may be configured to emit patterned light or structured light.

The image sensor unit may be configured to acquire two stereo images from the image of the light reflected from the second optical system.

According to various examples of the present disclosure, it is not necessary to provide a driving unit for adjusting the angle of each of the plurality of optical systems arranged inside the case of the intraoral scanner, and accordingly, the optical systems can be densely arranged in optimal positions inside the case.

In addition, according to various examples of the present disclosure, since it is possible to arrange a plurality of optical systems inside the case in a dense structure, an intraoral scanner with a small volume can be implemented, so that the intraoral scanner can be easily inserted into the oral cavity of a patient and easily moved or changed in direction in the oral cavity during use and perform precise tooth scanning.

In addition, according to various examples of the present disclosure, since it requires only one image sensor unit to acquire two stereo images from the images of light reflected from a plurality of optical systems, the manufacturing cost of the intraoral scanner can be reduced and internal configuration can be further optimized.

The effects of the present disclosure are not limited to the effects described above, and other effects that are not mentioned above can be clearly understood to those skilled in the art based on the description provided below.

The above and other objects, features and advantages of the present disclosure will be described with reference to the accompanying drawings described below, where similar reference numerals indicate similar elements, but not limited thereto, in which:.

Hereinafter, example details for the practice of the present disclosure will be described in detail with reference to the accompanying drawings. However, in the following description, detailed descriptions of well-known functions or configurations will be omitted if it may make the subject matter of the present disclosure rather unclear.

In the accompanying drawings, the same or corresponding components are assigned the same reference numerals. In addition, in the following description of various examples, duplicate descriptions of the same or corresponding components may be omitted. However, even if descriptions of components are omitted, it is not intended that such components are not included in any example.

The terms used in the present disclosure will be briefly described prior to describing the disclosed example(s) in detail. The terms used herein have been selected as general terms which are widely used at present in consideration of the functions of the present disclosure, and this may be altered according to the intent of an operator skilled in the art, related practice, or introduction of new technology. In addition, in specific cases, certain terms may be arbitrarily selected by the applicant, in which case the meaning of the terms will be described in detail in a corresponding description of the example(s). Therefore, the terms used in the present disclosure should be defined based on the meaning of the terms and the overall content of the present disclosure rather than a simple name of each of the terms.

In the present disclosure, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates the singular forms. Further, the plural forms are intended to include the singular forms as well, unless the context clearly indicates the plural forms.

In the present disclosure, when a portion is stated as "comprising (including)" a component, unless specified to the contrary, it intends to mean that the portion may additionally comprise (or include or have) another component, rather than excluding the same.

In the present disclosure, it is to be noted that the upper direction of the drawing may be referred to as "upper portion" or "upper side" of the configuration shown in the drawing, and the lower direction may be referred to as "lower portion" or "lower side". In addition, in the drawings, a portion between the upper and lower portions of the configuration shown in the drawings, or a portion other than the upper and lower portions may be referred to as "side portion" or "side". Relative terms such as "upper portion" and "upper side" may be used to describe the relationship between components shown in the drawings, and the present disclosure is not limited by these terms.

In the present disclosure, a direction toward the inner space of a structure may be referred to as "inside", and a direction projecting into the open outer space may be referred to as "outside". Relative terms such as "inside" and "outside" may be used to describe the relationship between components shown in the drawings, and the present disclosure is not limited by these terms.

In the present disclosure, the statement "A and/or B" means "A", or "B", or "A and B".

In the present disclosure, when a portion is stated as being connected to another portion, it intends to include not only an example in which the portions are directly connected, but also an example in which the portions are connected while having another component disposed therebetween.

Further, the term "module" or "unit" used in the present disclosure refers to a software or hardware component, and "module" or "unit" performs certain roles. However, the meaning of the "module" or "unit" is not limited to software or hardware. The "module" or "unit" may be configured to be in an addressable storage medium or configured to play one or more processors. Accordingly, as an example, the "module" or "unit" may include components such as software components, object-oriented software components, class components, and task components, and at least one of processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, micro-codes, circuits, data, database, data structures, tables, arrays, or variables. Furthermore, functions provided in the components and the "modules" or "units" may be combined into a smaller number of components and "modules" or "units", or further divided into additional components and "modules" or "units.

Advantages and features of the disclosed examples and methods of accomplishing the same will be apparent by referring to examples described below in connection with the accompanying drawings. However, the present disclosure is not limited to the examples disclosed below, and may be implemented in various forms different from each other, and the examples are merely provided to make the present disclosure complete.

<FIG> is a schematic diagram <NUM> showing a configuration in which an intraoral scanner <NUM> is connected to an oral 3D modeling and visualization system <NUM>.

For example, the intraoral scanner <NUM> may be inserted into the oral cavity of a patient by a practitioner to scan the teeth in a non-contact manner to capture a plurality of 2D image data. In addition, the intraoral scanner <NUM> may transmit a plurality of captured 2D image data to the system <NUM> or perform 3D oral structure modeling on its own based on the 2D image data.

The intraoral scanner <NUM> may be connected to the system through a network that is communicatively connected by wired or wireless manner. The network may be configured as a wired network such as an electrical connection line such as a copper cable, Ethernet, a wired home network (Power Line Communication), a telephone line communication device and RS-serial communication, a wireless network such as a mobile communication network, a wireless LAN (WLAN), Wi-Fi, Bluetooth, and ZigBee, or a combination thereof, depending on the installation environment.

The intraoral scanner <NUM> may exchange information, data such as 2D image data and 3D oral structure model data, etc. with the system <NUM>. The intraoral scanner <NUM> and the system <NUM> may be physically separately configured from each other as shown, but aspects are not limited thereto. For example, the intraoral scanner <NUM> and the system <NUM> may be integrated into a single computing device.

The system <NUM> may analyze at least two 2D image data or stereo images acquired from the intraoral scanner <NUM> to perform 3D oral structure modeling. In order to perform the above functions, the system <NUM> may include a computing device including a processor (e.g., CPU, GPU, etc.) capable of performing image processing and 3D modeling and a memory capable of storing 2D image data or 3D oral structure model data. As shown, the system <NUM> may include a communication unit <NUM>, a control unit <NUM>, and a display unit <NUM>. The communication unit <NUM> may be configured to transmit and receive information, data, etc. with the intraoral scanner <NUM>. Specifically, the communication unit <NUM> may transmit a command signal of the control unit <NUM> to the intraoral scanner <NUM> and receive image information of a target oral structure from the intraoral scanner <NUM>.

The control unit <NUM> may control the intraoral scanner <NUM> to capture an image of the target oral structure. Specifically, the control unit <NUM> may control a light source unit installed in the intraoral scanner <NUM> (e.g., <NUM> in <FIG>) to emit light toward at least one of a plurality of optical systems. In addition, the control unit <NUM> may control an image sensor unit (e.g., <NUM> in <FIG>) installed in the intraoral scanner <NUM> to detect the light reflected by at least one of a plurality of optical systems. The control unit <NUM> may control the image sensor unit to acquire two stereo images from the detected light image. The control unit <NUM> may control the display unit <NUM> to display two stereo images acquired from the image sensor unit. In addition, the control unit <NUM> may control so that 3D oral structure model data calculated from the two stereo images is visualized and displayed on the display unit <NUM>.

The display unit <NUM> may display the information, data, etc. transmitted from the intraoral scanner <NUM> or the control unit <NUM> in the form of images. The image displayed on the display unit <NUM> may include two stereo images or an image of the 3D oral structure model. The display unit <NUM> may include a display panel device such as an LED display, an OLED display, an LCD display, a touch display, etc..

<FIG> is a transparent perspective view of an intraoral scanner <NUM>. As shown in <FIG>, the intraoral scanner <NUM> may include a case <NUM>, the light source unit <NUM>, a first optical system <NUM>, second optical systems <NUM> and <NUM>, and the image sensor unit <NUM>.

The case <NUM> forms the exterior of the intraoral scanner <NUM> and may be configured to accommodate therein the light source unit <NUM>, the first optical system <NUM>, the second optical systems <NUM> and <NUM>, and the image sensor unit <NUM>. As shown in <FIG>, the case <NUM> may have a shape of a trapezoidal box extending in approximately one longitudinal direction, but is not limited thereto. For example, the case <NUM> may be formed in a rectangular parallelepiped shape, a cylindrical shape, a streamlined shape, or any shape suitable for insertion into the oral cavity.

An opening <NUM> may be formed at one end of the case <NUM>, for example, at the front portion. Specifically, the opening <NUM> may include an open portion formed in a specific direction at one end of the case <NUM>. In this case, the open portion of the opening <NUM> may be configured to allow the light generated or reflected inside the case <NUM> to be emitted to the outside and allow external light to be introduced into the case <NUM>. The opening <NUM> may be configured such that, when the intraoral scanner <NUM> is inserted into the oral cavity, the opening <NUM> is positioned at the innermost part of the oral cavity.

The light source unit <NUM> may be configured to emit light toward the front portion of the case <NUM>. In this case, the light emitted from the light source unit <NUM> may include patterned or structured light. The pattern of the light may be a straight line pattern, a dot pattern, or a pattern of any shape. If the patterned light is emitted to a subject <NUM> such as teeth in the oral cavity, a deformation of corresponding pattern may occur according to the 3D structure of the surface of the subject <NUM>. Accordingly, the deformation or location information of the pattern formed on the surface of the subject <NUM> may be used to identify and model the 3D structure of the subject <NUM>.

The light source unit <NUM> may be disposed at the other end of the case <NUM>. Specifically, the light source unit <NUM> may be accommodated at the other inner end of the case <NUM> opposite the one end of the case <NUM> where the opening <NUM> is formed. For example, the light source unit <NUM> may be fixedly disposed above the other inner end of the case <NUM>.

The light source unit <NUM> may be disposed within the case <NUM>, for example at the rear portion of the case <NUM>, but is not limited thereto. For example, the light source unit <NUM> may be disposed at any intermediate point between the one and other ends of the case <NUM>. That is, the light source unit <NUM> may be disposed at any position within the case <NUM> where it is easy to emit light toward the front portion of the case <NUM>. The light source unit <NUM> may be spaced apart from a first reflector <NUM> at an appropriate distance for easy scanning. For example, the light source unit <NUM> may be disposed as close to the first reflector <NUM> as possible.

The first optical system <NUM> may be configured to reflect the light emitted from the light source unit <NUM> toward the subject <NUM> and reflect the light reflected from the subject <NUM> toward the light source unit <NUM> or the second optical systems <NUM> and <NUM>. The first optical system <NUM> may include at least one reflector. For example, the first optical system <NUM> may include at least one mirror. The first optical system <NUM> may be disposed around the opening <NUM>. For example, the first optical system may be fixedly disposed on an inner surface of the case <NUM> adjacent to the opening <NUM>.

The second optical systems <NUM> and <NUM> may be configured to reflect the light reflected from the first optical system <NUM>. Specifically, the second optical systems <NUM> and <NUM> may reflect the light reflected from the first optical system <NUM> toward the image sensor unit <NUM>. In this case, the second optical systems <NUM> and <NUM> may reflect the light one or more times.

The second optical systems <NUM> and <NUM> may be disposed between the light source unit <NUM> and the first optical system <NUM>. Specifically, the light source unit <NUM> and the first optical system <NUM> may be fixedly disposed at both ends of the internal space of the case <NUM>, and the second optical systems <NUM> and <NUM> may be fixedly disposed at any position in the middle.

A gap (or optical path) may be formed in the center between the second optical systems <NUM> and <NUM>, so that the light emitted from the light source unit <NUM> may pass through the gap to reach the first optical system <NUM>. In another example, when the gap is not formed in the center between the second optical systems <NUM> and <NUM>, the light emitted from the light source unit <NUM> may bypass the second optical systems <NUM> and <NUM> and reach the first optical system <NUM>.

As shown in <FIG>, the second optical systems <NUM> and <NUM> may include the first reflector <NUM> and a second reflector <NUM>. The first reflector <NUM> may be configured to reflect light reflected from the first optical system <NUM>. The first reflector <NUM> may be fixedly disposed on an inner upper portion of the case <NUM>. The first reflector <NUM> may include two reflective surfaces <NUM> and <NUM>. The two reflective surfaces <NUM> and <NUM> may reflect the light reflected from the first optical system <NUM> toward the second reflector <NUM>. In addition, a gap may be formed between the two reflective surfaces <NUM> and <NUM>, so that the light emitted from the light source unit <NUM> may pass through the gap and reach the first optical system <NUM>.

The second reflector <NUM> may be configured to reflect the light reflected by the first reflector <NUM> toward the image sensor unit <NUM>. The second reflector <NUM> may be fixedly disposed on an inner lower portion of the case <NUM>. The second reflector <NUM> may include two reflective surfaces <NUM> and <NUM>. The two reflective surfaces <NUM> and <NUM> may reflect the light reflected from the first reflector <NUM> toward the image sensor unit <NUM>.

The position, direction, etc. of each of the two reflective surfaces <NUM> and <NUM> of the second reflector <NUM> may be appropriately set such that two images of the subject <NUM> that are each reflected by the two reflective surfaces <NUM> and <NUM> of the second reflector <NUM> and detected by the image sensor unit <NUM> do not overlap with each other. For example, two images detected by the image sensor unit <NUM> from the light reflected by the two reflective surfaces <NUM> and <NUM> of the second reflector <NUM> may each include one image of the subject <NUM>. In this case, the positions, directions, etc. of the two reflective surfaces <NUM> and <NUM> may be set such that the two images of the subject <NUM> detected by the image sensor unit <NUM> do not overlap with each other.

A driving unit for adjusting an angle of the first optical system <NUM> or the second optical systems <NUM> and <NUM> may not be installed in the case <NUM>. In this case, it is not necessary to dispose other electronic or mechanical components in the area inside the case where the first optical system <NUM> and the second optical systems <NUM> and <NUM> are disposed, and accordingly, it is possible to densely arrange the components inside the case. Therefore, since the optimal structure of the case <NUM> can be designed with the dense structure of the first optical system <NUM> and the second optical systems <NUM> and <NUM>, it is possible to implement the intraoral scanner <NUM> having a free scanning motion in the oral cavity and having a small volume.

The orientation of each normal vector of the reflective surfaces <NUM> and <NUM> of the first reflector <NUM> and the orientation of each normal vector of the reflective surfaces <NUM> and <NUM> of the second reflector <NUM> may be appropriately adjusted such that light reflected from the subject <NUM> may be guided to the image sensor unit <NUM>. A dihedral angle between infinite planes of each of the reflective surfaces <NUM> and <NUM> of the first reflector <NUM> may correspond to a minor angle, that is, an angle smaller than <NUM> degrees, and a dihedral angle between the infinite planes of the reflective surfaces <NUM> and <NUM> of the second reflector <NUM> may correspond to a major angle, that is, an angle greater than <NUM> degrees. Alternatively, the dihedral angle between the infinite planes of each of the reflective surfaces <NUM> and <NUM> of the first reflector <NUM> may correspond to a major angle, and the dihedral angle between the infinite planes of the reflective surfaces <NUM> and <NUM> of the second reflector <NUM> may correspond to a minor angle.

The image sensor unit <NUM> may be configured to detect the light reflected from the second optical systems <NUM> and <NUM>. The image sensor unit <NUM> may be configured to acquire two stereo images from the light reflected from the second optical systems <NUM> and <NUM>. Specifically, the image sensor unit <NUM> may acquire together the images of the two lights respectively reflected by the two reflective surfaces <NUM> and <NUM> of the second reflector <NUM>. As described above, the intraoral scanner <NUM> includes the second optical systems <NUM> and <NUM> having a plurality of reflective surfaces <NUM>, <NUM>, <NUM>, and <NUM> and thus can acquire two stereo images with only one image sensor unit <NUM>. The two stereo images acquired from the image sensor unit <NUM> may be used for 3D oral structure modeling that is executed by a processor.

The image sensor unit <NUM> may be disposed within the case <NUM>, for example at the rear portion of the case <NUM>. Specifically, the image sensor unit <NUM> may be accommodated at the other inner end of the case <NUM> to face the one end of the case <NUM> where the opening <NUM> is formed. For example, the image sensor unit <NUM> may be fixedly disposed on the inner lower portion of the case <NUM> adjacent to the light source unit <NUM>.

Although it has been described above that the first reflector <NUM> is fixedly disposed on the inner upper portion of the case <NUM> and the second reflector <NUM> is fixedly disposed on the inner lower portion of the case <NUM>, aspects are not limited thereto. For example, the first reflector <NUM> may be fixedly disposed on the inner lower portion of the case <NUM> and the second reflector <NUM> may be fixedly disposed on the inner upper portion of the case <NUM>. In this case, the light source unit <NUM> may be fixedly disposed on an inner lower portion of the other end of the case <NUM>, and the image sensor unit <NUM> may be fixedly disposed on an inner upper portion of the case <NUM> adjacent to the light source unit <NUM>.

<FIG> is a transparent side view of the intraoral scanner <NUM>. The descriptions of the components shown in <FIG> that correspond to the components shown in <FIG> will be omitted.

Light may be emitted from the light source unit <NUM> and pass through the gap of the first reflector <NUM>. The light passed through the gap of the first reflector <NUM> may be reflected toward the subject by the first optical system <NUM>. In this case, the light may pass through the open portion formed on one side of the opening <NUM>. The light reflected from the subject may be reflected toward the first reflector <NUM> by the first optical system <NUM>. The light reflected by the first reflector <NUM> may be reflected toward the image sensor unit <NUM> by the second reflector <NUM>.

Additionally, the intraoral scanner <NUM> may acquire an image of the subject using light emitted from an additional light source other than the light source unit <NUM>. For example, the light emitted from an additional light source installed in the intraoral scanner <NUM> or from an external additional light source may be reflected on the subject and reach the first optical system <NUM>. The light reflected from the first optical system <NUM> may be sequentially reflected by the first reflector <NUM> and the second reflector <NUM> and reach the image sensor unit <NUM>.

<FIG> is a transparent perspective view of an intraoral scanner <NUM>. The descriptions of the components shown in <FIG> that correspond to the components shown in <FIG> will be omitted. As shown in <FIG>, the intraoral scanner <NUM> may include a case <NUM>, a light source unit <NUM>, a first optical system <NUM>, a second optical system <NUM>, and an image sensor unit <NUM>.

The second optical system <NUM> may reflect light reflected from the first optical system <NUM> toward the image sensor unit <NUM>. In this case, the second optical system <NUM> may reflect the light one or more times.

The second optical system <NUM> may be disposed between the light source unit <NUM> and the first optical system <NUM>. Specifically, the light source unit <NUM> and the first optical system <NUM> may be fixedly disposed at both ends of the internal space of the case <NUM>, and the second optical system <NUM> may be fixedly disposed at any position in the middle.

Unlike the second optical systems <NUM> and <NUM> of <FIG>, the second optical system <NUM> may include a pair of prisms. As shown in <FIG>, the second optical system <NUM> may include a first prism <NUM> and a second prism <NUM>.

A gap (or optical path) is formed between the first prism <NUM> and the second prism <NUM>, so that the light emitted from the light source unit <NUM> may pass through the gap described above and reach the first optical system <NUM>. If a gap is not formed between the first prism <NUM> and the second prism <NUM>, the light emitted from the light source unit <NUM> may pass through the second optical system <NUM> and reach the first optical system <NUM>.

As shown in <FIG>, the first prism <NUM> may include a pair of opposing reflective surfaces <NUM> and <NUM>, and the second prism <NUM> may include a pair of opposing reflective surfaces <NUM> and <NUM>. The upper reflective surface <NUM> of the first prism <NUM> and the upper reflective surface <NUM> of the second prism <NUM> may reflect the light reflected from the first optical system <NUM> toward the lower reflective surface <NUM> of the first prism <NUM> and the lower reflective surface <NUM> of the second prism <NUM>, respectively. In addition, the lower reflective surface <NUM> of the first prism <NUM> and the lower reflective surface <NUM> of the second prism <NUM> may reflect the light reflected from the upper reflective surface <NUM> of the first prism <NUM> and the upper reflective surface <NUM> of the second prism <NUM> toward the image sensor unit <NUM>, respectively. Accordingly, the light reflected by the first optical system <NUM> may be reflected by the pair of opposing reflective surfaces <NUM> and <NUM> of the first prism <NUM> and the pair of opposing reflective surfaces <NUM> and <NUM> of the second prism <NUM> and reach the image sensor unit <NUM>.

The position, orientation, etc. of each of the lower reflective surface <NUM> of the first prism <NUM> and the lower reflective surface <NUM> of the second prism <NUM> may be appropriately set such that two images of the subject respectively reflected by the two lower reflective surfaces <NUM> and <NUM> and detected by the image sensor unit <NUM> do not overlap with each other. For example, each of the two images detected by the image sensor unit <NUM> from light reflected by the two lower reflective surfaces <NUM> and <NUM> may include one image of the subject. In this case, the positions, directions, etc. of the two lower reflective surfaces <NUM> and <NUM> may be set such that the two images of the subject detected by the image sensor unit <NUM> do not overlap with each other.

The orientation of each normal vector of the reflective surfaces <NUM> and <NUM> of the first prism <NUM> and the orientation of each normal vector of the reflective surfaces <NUM> and <NUM> of the second prism <NUM> may be appropriately adjusted such that light reflected from the subject may be guided to the image sensor unit <NUM>. A dihedral angle between an infinite plane of one reflective surface <NUM> of the first prism <NUM> and an infinite plane of one reflective surface <NUM> of the second prism <NUM> may correspond to a minor angle, and a dihedral angle between an infinite plane of the other reflective surface <NUM> of the first prism <NUM> and an infinite plane of the other reflective surface <NUM> of the second prism <NUM> may correspond to a major angle. Alternatively, the dihedral angle between the infinite plane of one reflective surface <NUM> of the first prism <NUM> and the infinite plane of one reflective surface <NUM> of the second prism <NUM> may correspond to a major angle, and the dihedral angle between the infinite plane of the other reflective surface <NUM> of the first prism <NUM> and the infinite plane of the other reflective surface <NUM> of the second prism <NUM> may correspond to a minor angle.

As described above, by implementing the second optical system <NUM> using a pair of prisms <NUM> and <NUM>, the arrangement structure and design of the second optical system inside the case <NUM> can be further optimized. That is, compared to implementing the second optical system using a plurality of reflectors or mirrors inside the case <NUM>, the implementation using a pair of prisms can allow the structure for disposing or fixing the second optical system inside the case <NUM> to be simpler, and can subsequently allow the internal structure of the case <NUM> to be denser.

<FIG> is a transparent side view of the intraoral scanner <NUM>. The descriptions of the components shown in <FIG> that correspond to the components shown in <FIG> and <FIG> will be omitted.

Light may be emitted from the light source unit <NUM> and pass through a gap between the first prism <NUM> and the second prism <NUM>. The light passed through the gap may be reflected toward the subject by the first optical system <NUM>. In this case, the light may pass through the open portion formed on one side of the opening <NUM>. The light reflected from the subject may be reflected toward the second optical system <NUM> by the first optical system <NUM>. The light reflected by the upper reflective surfaces of the first prism <NUM> and the second prism <NUM> may be reflected toward the image sensor unit <NUM> by the lower reflective surfaces of the first prism <NUM> and the second prism <NUM>.

Additionally, the intraoral scanner <NUM> may acquire an image of the subject using light emitted from an additional light source other than the light source unit <NUM>. For example, the light emitted from an additional light source installed in the intraoral scanner <NUM> or from an external light source may be reflected on the subject and reach the first optical system <NUM>. The light reflected from the first optical system <NUM> may be sequentially reflected by the upper and lower reflective surfaces of the second optical system <NUM> and reach the image sensor unit <NUM>.

Certain examples of the present invention have been described above for purposes of illustration only, and those skilled in the art with ordinary knowledge of the present disclosure will be able to make various modifications, changes and additions within the scope of the invention, as defined in the appended claims.

Claim 1:
An intraoral scanner (<NUM>, <NUM>) comprising:
a case (<NUM>) including an opening (<NUM>);
a light source unit (<NUM>) disposed within the case (<NUM>) and configured to emit light toward the opening;
a first optical system (<NUM>) reflecting the light emitted from the light source unit (<NUM>) toward a subject (<NUM>) and reflecting light reflected from the subject (<NUM>) toward the light source unit (<NUM>);
a second optical system (<NUM>, <NUM>) disposed between the light source unit (<NUM>) and the first optical system (<NUM>) and reflecting light reflected from the first optical system (<NUM>); and
an image sensor unit (<NUM>) that detects the light reflected from the second optical system (<NUM>, <NUM>),
wherein the second optical system (<NUM>, <NUM>) includes:
a first reflector (<NUM>) configured to reflect the light reflected from the first optical system (<NUM>); and
a second reflector (<NUM>) configured to reflect the light reflected by the first reflector (<NUM>) toward the image sensor unit (<NUM>),
characterised in that the first reflector (<NUM>) includes two reflective surfaces (<NUM>, <NUM>) configured such that a dihedral angle between each infinite plane forms a minor angle, and the second reflector (<NUM>) includes two reflective surfaces (<NUM>, <NUM>) configured such that a dihedral angle between each infinite plane forms a major angle, or
the first reflector (<NUM>) includes two reflective surfaces (<NUM>, <NUM>) configured such that a dihedral angle between each infinite plane forms a major angle, and the second reflector (<NUM>) includes two reflective surfaces (<NUM>, <NUM>) configured such that a dihedral angle between each infinite plane forms a minor angle.