KR20160038923A - Scanner for oral cavity having No-moving variable focus optics and Oral cavity scanning method thereof - Google Patents

Abstract

An oral cavity scanner having an idle optical system according to an embodiment of the present invention comprises: an oral cavity scanner body; an optical source which is installed inside the oral cavity scanner body and has a color of at least one wavelength; an optical pipe which is configured to homogenize incident light using internal total reflection while the light passes through the optical pipe, wherein the light enters at a surface of the optical pipe facing the optical source and exits from an opposite surface; a microlens array which focuses the light which is homogenized in the optical pipe; a beam splitter which transmits the light, which is focused and delivered by the microlens array, and reflects the rest light to a predetermined angle; an idle optical system which varies a refractive index of the light, which passes through the beam splitter, in association with a control signal from a control unit and focuses the light, which passes through the beam splitter, on a surface of a tooth; a relay optical system which delivers the light, which passes through the idle optical system, in a predetermined size; a reflection member which reflects the light, which is delivered from the relay optical system, to the surface of a tooth through a window formed at a position facing the oral cavity scanner body; and an imaging unit on which the light, which is reflected on the surface of a tooth and delivered through the reflection member, the relay optical system, and the beam splitter, is focused to form a digital image. A focusing set value of the idle optical system can be varied according to the kind of the tooth whose image is formed on the imaging unit.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an oral cavity scanning optical system and an oral cavity scanning method using the same,

The present invention relates to an oral scanner, and more particularly, to an oral scanner capable of focusing using a non-driving optical system that can optimize the configuration of an optical system according to the type and wavelength of a light source.

Generally, in a dental hospital or the like, impression taking is performed to produce a gypsum model for a patient's teeth, thereby treating and treating the damaged tooth of the patient. As an adjunctive method, radiation such as x - rays was projected onto the affected part of the mouth to acquire a two - dimensional image or use computerized tomography (CT) pictures.

However, this method causes a lot of inconvenience to the patient. In order to make a gypsum model, it is necessary to wait for a period of more than a certain period of time with the frame containing the gypsum in the mouth, and if the patient does not hold it correctly or the frame moves while it is biting, I can not. In addition, an error may occur according to the skill of the operator, and even if the frame is made correctly, errors may occur during the model making process according to the framework of the technician. In particular, because of the use of gypsum molds by several patients, hygiene problems may arise if disinfection is not done sufficiently.

Recently, techniques for accurately measuring the shape and state of a patient's teeth by scanning / photographing the tooth state inside the oral cavity of a patient in three dimensions without physical contact using an optical instrument have been actively studied.

The present embodiment provides an oral scanner equipped with a non-driving optical system that is suitable for a small optical system and can provide quick response in various light sources and wavelength ranges and can provide noise, vibration, life, and weight.

The mouth scanner having the non-driving optical system according to the present embodiment includes a mouth scanner body; A light source installed inside the mouth scanner body and having a color of at least one wavelength; A light pipe through which light is incident on a surface facing the light source, light incident on the opposite surface passes through the light pipe, and uniformly configures incident light using total internal reflection during the passage of light; A microlens array for condensing the homogenized light in the light pipe; A beam splitter through which light transmitted through the microlens array is transmitted, and the other light is reflected at a predetermined angle; A non-driving optical system for varying a refractive index of light passing through the beam splitter in cooperation with a control signal of a control unit and focusing the light passing through the beam splitter on a tooth surface; A relay optical system for transmitting light having passed through the non-driving optical system at a predetermined size; A reflecting member for reflecting the light transmitted from the relay optical system to a tooth surface through a window formed at an opposite position of the mouth scanner body; And an imaging unit which is reflected from the tooth surface and is transmitted to a reflecting member, a relay optical system, a driving non-driving optical system, and a beam splitter to form a digital image by reflecting the reflected light, The focusing setting value can be varied depending on the type of teeth to be formed.

A polarizing member may be further provided between the light source and the light pipe.

The light pipe may be formed of a light transmitting material and may be a hexagonal homogenizing rod having a predetermined length.

The relay optical system may include at least one objective telecentric lens whose path of principal ray is parallel to the optical axis.

Wherein the imaging unit comprises: an imaging polarizing member on which light transmitted through the beam splitter is incident; An imaging optical system having at least one lens through which the light of the polarizing member passes; A pinhole array selectively transmitting light passing through the imaging optical system; An imaging element in which light transmitted through the pinhole array forms an image; And a circuit board on which the imaging device is mounted.

Wherein the lenses constituting the microlens array, the drivingless optical system, and the relay optical system are fixedly arranged so as not to move along the optical axis, and the lens constituting the no-driving optical system has a focusing position of the light source through a change in refractive index Can be varied.

The light source may be an optical element that emits light of red, green, and blue wavelengths.

A method of scanning an oral cavity using an oral scanner having a non-driving optical system according to an embodiment of the present invention includes: obtaining a tooth image by imaging light emitted from a light source on a tooth surface; Comparing the acquired tooth image with a database; Determining a tooth type; Selecting an optimal focusing setting value according to the determined tooth type; Applying a focusing setting value to the driveless optical system; And if the tooth type identification is not possible, detailing the scanning fault section.

According to the present embodiment as described above, unlike the conventional confocal scanning type oral scanners, since the motor driving parts for image acquisition are eliminated and the drivingless optical system is provided, noise, vibration and limited lifetime And the like can be prevented.

In addition, since the shape image of the tooth scanned in real time is compared with the shape stored in the database, and the optimal setting value of the non-driving optical system is given according to the tooth type, quick and accurate scanning of the tooth image in the oral cavity is possible.

1 is a schematic view of an oral scanner according to the present embodiment,
Figure 2 is a block diagram of the oral scanner of Figure 1;
FIGS. 3 and 4 are views showing an exemplary operation of the driveless optical system according to the present embodiment,
5 is a view of an oral-type scanner system according to the present embodiment,
FIG. 6 is a flowchart illustrating a spherical scanning method using an oral scanner according to the present embodiment.

Hereinafter, an oral scanner having a non-driving optical system according to the present embodiment and an oral scanning method using the same will be described with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

In addition, the same or corresponding components are denoted by the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. For convenience of explanation, the size and shape of each constituent member shown may be exaggerated or reduced have.

On the other hand, terms including an ordinal number such as a first or a second may be used to describe various elements, but the constituent elements are not limited by the terms, and the terms may refer to a constituent element from another constituent element It is used only for the purpose of discrimination.

Fig. 1 is a schematic diagram of an oral scanner according to the present embodiment, Fig. 2 is a block diagram of the oral scanner of Fig. 1, and Figs. 3 and 4 are diagrams exemplarily showing the operation of the undriven optical system according to the present embodiment FIG. 5 is a view of the oral-type scanner system according to the present embodiment, and FIG. 6 is a flowchart illustrating a spherical-scanning method using the oral-type scanner according to the present embodiment.

1 and 2, the oral scanner 1000 according to the present embodiment includes a light source 10, an optical system, a non-driving optical system 100, a relay optical system 60 and a reflecting member 70, Unit 200 as shown in FIG. Here, the optical system may include a polarizing member 20, a light pipe 30, a microlens array 40, and a beam splitter 50. However, it is not limited thereto, and the optical system can be configured in various ways according to the design. For example, the polarization member 20 and the like may be omitted, and the light pipe 30 and the microlens array 40 may be replaced by a single optical system, or all of them may be constituted by one optical system.

The light source 10 irradiates light using a semiconductor device such as an LED, and may be formed to have at least one light source element inside the oral-type scanner body 1001 as shown in FIG. For example, according to the present embodiment, it may be composed of red, green and blue light source elements 11, 12, and 13. However, the present invention is not limited to this, and it may be configured to irradiate light of a single wavelength, or to irradiate linear laser light.

The polarizing member 20 is for filtering the direction in which the light emitted from the light source 10 vibrates uniformly, and may be filtered in either the x-axis direction or the y-axis direction. On the other hand, the polarizing member 20 may be disposed on the optical path in the form of a separate filter, or may be formed with a coating or a filter on the light irradiation surface of the light source elements forming the light source.

The light pipe 30 may be provided as a homogenizing rod, and the heterogeneous light source may be uniformly formed by using total internal reflection regardless of the spectral characteristics of the light source 10. The light pipe 30 may be formed in a hexagonal columnar shape and may be formed of a light transmitting material so that light can be transmitted.

The microlens array 40 can condense the light homogenized in the light pipe 30 and transmit it to the beam splitter 50 side. The microlens array 40 may be provided as a liquid crystal microlens array capable of improving the light condensing efficiency. In this case, it is also possible to electrically adjust the focal distance and the condensing efficiency. In the case of a liquid crystal microlens, the light converging characteristic can be controlled by controlling the refractive index distribution in the liquid crystal layer by using a patterned electrode structure and a bending structure formed on the substrate surface.

The beam splitter 50 can form the optical path of the optical system by using the characteristic that the light satisfying the specific condition is transmitted and the light not satisfying the condition is reflected. According to the present embodiment, the beam splitter 50 may be provided with a polarization beam splitter (PBS). The polarized beam splitter can transmit the P polarized light and reflect the S polarized light perpendicular to the P polarized light, so that the polarization state of the incident light can be divided into orthogonal components. At this time, the reflective surface reflecting S-polarized light can be coated using a dielectric multi-layered film, thereby minimizing optical loss. However, the present invention is not limited to this, and a variable beam beam splitter (VBS) can be used that uses a light source such as a laser beam or the like, and adjusts incident and reflection angles when external light amount adjustment is required. In this case, any polarization direction can be used, and the transmittance characteristic can be determined according to the polarization characteristic state. The beam splitter 50 may be formed of a light transmitting material or a synthetic quartz material.

The drivingless optical system 100 can be fixedly arranged with respect to the optical axis C and can vary the refractive index of light passing therethrough in conjunction with the control signal of the control unit 300. [ The drivingless optical system 100 may include at least one lens that can adjust the focal length of the light of the light source 10 by changing the refractive index of the light passing through the lens in a fixed state with respect to the optical axis C. have.

The non-driving optical system 100 may be configured in various manners, for example, in the form of a variable bending plate. The drivingless optical system 100 composed of a variable refractive sheet can include a plurality of liquid crystal cells (not shown) that are optically changed in response to a driving voltage. For example, it is also possible to adjust the refractive index and / or the viewing angle if a plurality of liquid crystal cells can be dispersed in the matrix substrate. Therefore, when the driving voltage is applied, the refractive index of the variable refractive sheet changes. As shown in FIG. 3, in the 0 V (zero voltage) state where no voltage is applied, light passes through without change in the refractive index. However, when a constant voltage is applied, as shown in FIG. 4, the refractive index of the variable refractive sheet changes, and a spatial gradient (gradient) from the optical center to the edge is generated, The focal distance can be changed.

Therefore, as shown in FIG. 3, in the off state of the driving voltage, the light transmitted to the tooth surface before and after the non-driving optical system constituted by the variable refractive sheet can be transmitted while maintaining the parallel light form. However, when the driving voltage is turned on, the subject light changes from a parallel light form to a convergent light form while passing through the variable refractive sheet, and focuses at a predetermined focal distance along the optical axis (C) direction. At this time, the focal length is changed while varying the refractive power according to the high and low levels of the driving voltage, and the autofocusing function of adjusting the focal distance by controlling the driving voltage can be implemented. At least one pair of conductive legs for power supply may be provided on the variable bending section.

In the above-described embodiment, the configuration of the driveless optical system 100 using the variable bending plate is exemplarily described, but the present invention is not limited thereto. The non-driving optical system 100 can be replaced with a configuration using a piezoelectric element, a configuration using a MEMS actuator, a liquid lens, or the like other than the above-described variable bending section, and in a state where the lens is fixed so as not to move in the direction of advancing or retracting with respect to the optical axis Any structure can be used as long as it can change the refractive index.

The relay optical system 60 can transfer the path of the principal ray of light focused by the non-driving optical system 100 in parallel with the optical axis. In the case of a general lens, the relay optical system 60 according to the present embodiment is composed of a telecentric lens, and has a distribution of principal rays diverged by issuing toward an object. However, Can be formed so as to be parallel to the optical axis. In general, the light from the light source 10, which is provided by coaxial illumination, must be transmitted so as to have the same directionality, so that the brightness of the tooth surface to be imaged can be uniformly formed. Therefore, when the relay optical system 60 is composed of a telecentric lens, the divergent illumination and the light of the light receiving component are optimized for the reflection condition of the sample, thereby ensuring uniform brightness and optical efficiency. According to the present embodiment, the relay optical system 60 composed of the telecentric lens described above may be provided as an objective telecentric lens so that the principal ray may have a parallel distribution in the object side direction .

The reflective member 70 reflects the pattern light having passed through the beam splitter 50 and forms an image on the tooth surface T through a window 1002 disposed at a corresponding position of the oral scanner body 1001, The reflected light reflected from the tooth surface T can be transmitted to the reflecting surface of the beam splitter 50. [ The provision of the reflecting member 70 not only makes it easy to take an image of the upper surface of the tooth surface T, but also solves a problem caused by a limitation of space in which a tooth is to be photographed in a narrow internal cavity.

The imaging unit 200 receives the image of the tooth surface T reflected through the reflection member 70 from the reflecting surface of the beam splitter 50 to form a three-dimensional image. The imaging unit 200 may be configured in various ways according to the type of the light source 10 to be used. For example, as shown in FIG. 2, the imaging unit 200 includes an imaging polarizing member 210, an imaging optical system 220, 230, an image pickup device 240, and a printed circuit board 250.

The image polarizing member 210 can filter the light that has been formed through the reflection surface of the beam splitter 50 again to uniformly configure the components of the light to be formed. A three-dimensional integrated image can be formed through the imaging optical system 220 and the pinhole array 230 with the filtered light. That is, the integral imaging technique is a technique capable of forming a three-dimensional image having a continuous viewpoint within a cine angle. That is, the point light source array is formed from the parallel light through the pinhole array 230 using the lens array, and the three-dimensional image and the two-dimensional image are both obtained by using the Polymer-Dispersed Liquid Crystal (PDLC) (240). ≪ / RTI > In this case, since only one imaging element 240 is used, the structure is simple and power consumption can be reduced. However, the present invention is not limited thereto, and the configuration of the imaging unit 200 may be replaced with the configuration of a general image capturing apparatus in addition to the above configuration.

The image pickup device 240 can be mounted on the printed circuit board 250 and the two-dimensional and three-dimensional image information acquired by the imaging unit 200 can be transmitted to the control unit 300 side .

The control unit 300 is for controlling the operation of the oral scanner including the driving-less optical system 100, and may include a database of tooth shape information in an unillustrated storage unit. The control unit 300 compares the image information of the tooth surface T acquired by the imaging unit 200 with the image of the previously stored tooth shape database to determine the type of the taken tooth, It is possible to give the optimum set value of the power supply 100.

The user uses the oral scanner according to the present embodiment in a state of being spaced apart from the tooth surface T by a certain distance. However, since the internal space of the oral cavity is narrow and the maximum separation distance is limited, . Accordingly, when the type of tooth is determined using the image of the scanned tooth surface T, the predetermined optimal focusing setting value is transmitted to the no-driving optical system 100, and the focusing operation can be completed with the minimum refractive index change So that the response speed of the apparatus can be improved.

5, the oral scanner 1000 according to the present embodiment includes a system body 1100 including a controller 300, a wiring member (not shown) for connecting the oral scanner 1000 and the system body 1100 1200 and a display unit 1300. The display unit 1300 includes a display unit 1300,

A power supply unit (not shown) and a control unit 300 may be installed inside the system body 1100 and an operation unit 1110 may be provided at an exposed portion of the system body 1100 to control the operation of the oral scanner 1000.

The wiring member 1200 is connected to the system body 1100 at one end and connected to the oral scanner 1000 to supply power to the oral scanner 1000, To the control unit 300 side.

The display unit 1300 provides the user with the image information obtained from the oral scanner 1000 in real time so that the user can visually confirm whether or not the image of the tooth surface T actually being scanned is being normally scanned .

The control unit 300 may connect the three-dimensional printer 400 using the connection unit 1400 to directly form a three-dimensional model corresponding to the image of the obtained tooth surface T. As described above, when the image of the tooth surface T is acquired using the three-dimensional scanning, it is possible to manufacture the same model as the actual patient's teeth.

FIG. 6 is a flowchart schematically illustrating a method of scanning an oral cavity using an oral scanner equipped with a non-driving optical system according to the present embodiment.

The image of the tooth surface T can be obtained using the oral scanner 1000 according to the present embodiment. At this time, when the oral scanner 1000 is moved along the tooth surface T, it can proceed in order of tooth number. The tooth number can be FDI World Dental Federation Notation. In other words, the permanent teeth start from the upper right side of the upper main needle 11, the upper right wisdom teeth 18, the upper left teeth from 21 to 28, the mandibular teeth from 31 to 38, and the lower right teeth from 41 to 48 Can be called. Accordingly, in proceeding in order of the tooth number, the user may manually input the tooth number first, and then scan the tooth in the order. However, the present invention is not limited thereto, and it is also possible to automatically confirm the type of the tooth through image processing through the continuously acquired scanning image after the user randomly scans the tooth (S10).

When the tooth image is acquired in step S10, the control unit 300 compares the three-dimensional image information acquired by the imaging unit 200 of the oral scanner 1000 with the image stored in the database. At this time, when the scanning is performed according to the tooth number as in the step S10, it is possible to compare with the image of the existing tooth mapped to the tooth number, so that the comparison operation can be performed more quickly and accurately. However, since the user may not perform scanning according to the tooth number, it is possible to select whether to scan according to the tooth number or random scanning through the setting mode (S20).

At step S20, the tooth image stored in the database and the scanned tooth image are compared to determine what kind of tooth is currently scanned. When the overall contour scanning of the teeth is terminated, the determination of the tooth type can be performed by comparing the information with the image of the database directly, or it is also possible to perform the comparison determination using only the partial images acquired before the whole tooth shape is scanned . Oral scanning is usually performed by continuous shooting without stopping, rather than by tooth, so if too much time is spent to compare tooth types during imaging, the next tooth may be scanned (S30).

When the tooth type is determined in step S30, the optimum focusing setting value for the tooth can be selected. For example, in the case of teeth 11, 21, 31, and 41 corresponding to the front teeth, since the tip of the tooth is narrow and sharp, the tooth area is narrow, so that the focusing position may be abruptly changed to the focusing position. On the other hand, in the case of teeth 16, 17, 26, 27, 36, 37, 46, 47 corresponding to the molar teeth, since the upper surface is wide and flat, the tooth area is wide and the focusing position may be gradually changed. Therefore, it is possible to perform a quick and accurate oral scanning in the case of performing the scanning by setting the setting value in advance. In particular, since the focusing area and the range are set in advance, the influence of the scanning disturbance factor due to bleeding or foreign matter can be minimized (S40).

If the focusing setting value for each tooth is selected in S40, the controller 300 may apply the set value to the non-driving optical system 100 side to perform the scanning driving. At this time, the user normally moves the oral scanner 1000 according to the present embodiment along the tooth surface T at a constant speed. The display unit 1300 outputs a three-dimensional image of the obtained tooth in real time, It is possible to confirm whether or not the mouth scanning is performed correctly. On the other hand, the set value in step S40 is output to the display unit 1300, and whether or not the set value is selected according to the tooth number such as the front teeth, canines, etc., together with the type, condition, (S50).

On the other hand, if it is determined in step S30 that accurate scanning can not be performed due to a user's mistake, bleeding, foreign matter, or the like, or if images of adjacent single image information are suddenly changed, 1300) can be displayed. At the same time, the control unit may subdivide the scanning fault section so as to adjust the setting value so that the erroneously scanned portion can be normally scanned. If the image is not erroneously scanned, since the area between the respective images is formed to be excessively wide, the tomographic image section can be further subdivided so as to correct it. Then, the procedure proceeds to S10 in a segmented single layer section to acquire the tooth image again (S60).

According to this embodiment, since the lens constituting the optical system does not move forward or backward along the optical axis but changes only the refractive index of the light passing through the voltage adjustment, the operating noise of the driving motor constituting the conventional auto focusing apparatus It is not affected by vibration. In addition, since the drive motor is not used, even if the motor is used for a long period of time, there is no problem of a life-time degradation due to a drive motor failure or reliability deterioration.

The embodiments of the present invention described above and shown in the drawings should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art will be able to modify the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the scope of the present invention as long as they are obvious to those skilled in the art.

10; Light source 20; The polarizing member
30; Light pipe 40; Micro lens array
50; Beam splitter 60; Relay optical system
70; Reflective member 100; Non-driving optical system
200; An imaging unit 210; The imaging polarizing member
220; Imaging optics 230; Pinhole array
240; An imaging device 250; Printed circuit board
300; A control unit 400; 3D printer

Claims (10)

Mouth scanner body;
A light source installed inside the mouth scanner body and having a color of at least one wavelength;
An optical system that transmits light of the light source and reflects light reflected from the tooth surface;
A non-driving optical system for varying a refractive index of light passing through the beam splitter in cooperation with a control signal of a control unit and focusing the light passing through the beam splitter on a tooth surface;
A relay optical system for transmitting light having passed through the non-driving optical system at a predetermined size;
A reflecting member for reflecting the light transmitted from the relay optical system to a tooth surface through a window formed at an opposite position of the mouth scanner body; And
And an imaging unit, wherein light reflected from the tooth surface is imaged through the optical system to form a digital image,
The non-driving optical system includes:
And a non-driving optical system in which a focusing setting value is varied according to the type of tooth image formed on the imaging unit.
The optical system according to claim 1,
A light pipe through which light is incident on a surface facing the light source, light incident on the opposite surface passes through the light pipe, and uniformly configures incident light using total internal reflection during the passage of light;
A microlens array for condensing the homogenized light in the light pipe; And
And a beam splitter that transmits light that is condensed and transmitted in the microlens array and reflects the other light at a predetermined angle.
3. The method of claim 2,
Driving optical system in which a polarizing member is additionally provided between the light source and the light pipe.
The light pipe according to claim 2,
An oral scanner having a non-driving optical system formed of a light-transmitting material and being a hexagonal homogenizing rod having a predetermined length.
The relay optical system according to claim 1,
Driving optical system comprising at least one objective telecentric lens whose path of principal ray is parallel to the optical axis.
The imaging apparatus according to claim 2,
An imaging polarizing member through which light transmitted through the beam splitter is incident;
An imaging optical system having at least one lens through which the light of the polarizing member passes;
A pinhole array selectively transmitting light passing through the imaging optical system;
An imaging element in which light transmitted through the pinhole array forms an image; And
And a circuit board on which the imaging device is mounted.
3. The method of claim 2,
Lenses constituting the microlens array, the drivingless optical system and the relay optical system are fixedly arranged so as not to move along the optical axis,
Driving optical system in which a focusing position of the light source is varied through a refractive index change in a fixed position.
The light source according to claim 1,
Driving optical system which is an optical element for irradiating light of wavelengths of red, green and blue.
Acquiring a tooth image by imaging light irradiated from a light source on a tooth surface;
Comparing the acquired tooth image with a database;
Determining a tooth type;
Selecting an optimal focusing setting value according to the determined tooth type;
Applying a focusing setting value to the driveless optical system; And
And if the tooth type can not be confirmed, detailing the scanning fault section.
10. The method of claim 9,
Further comprising the step of manually inputting a tooth type before the step of acquiring the tooth image.

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