Optical system, intraoral digital impression scanner provided with optical system, and image acquisition method

Abstract

The present invention relates to an optical system, comprising an optical path emission subsystem, a scanning mirror (6), and an image receiving and processing subsystem. The optical path emission subsystem comprises an illumination module (1), a light modulation module (4), and a curved prism (21). The curved prism comprises a light incident surface (21A), a reflective-transmissive composite interface (21B), and a curved surface (21C) coated with a reflective film. The curved prism is configured to change the direction of an optical path and focus the optical path, such that the optical path enters from the light incident surface, is reflected by the reflective-transmissive composite interface, is reflected and focused by the curved surface, and then exits from the reflective-transmissive composite interface and enters the light modulation module at a specific angle. The present invention further relates to an intraoral digital impression scanner provided with the optical system. The optical system significantly reduces the spatial size of the intraoral digital impression scanner and meets the requirements of miniaturization and portability by means of replacing a traditional combination of a lens and a reflector with the curved prism.

Description

Optical system, digital dental impression instrument equipped with the optical system, and image acquisition method Technical Field

[0001] This invention relates to the field of medical devices, specifically to an optical system and a digital dental impression device equipped with the optical system. Optionally, this invention also relates to an image acquisition method utilizing the aforementioned optical system. Background Technology

[0002] A digital dental impression device is a device that uses computer technology and 3D imaging technology to acquire and reconstruct dental impressions. With technological advancements and increasing market demand, the requirements for digital dental impression devices are gradually becoming more stringent. As a handheld medical device, traditional digital dental impression devices are large and complex in structure, lacking sufficient flexibility in use. Therefore, the demand for miniaturized digital dental impression devices is becoming increasingly apparent in the dental healthcare industry.

[0003] On September 17, 2015, applicants Suzhou Qisda Optoelectronics Co., Ltd. and Qisda Technology Co., Ltd. filed Chinese invention patent application with publication number CN105266815A, which discloses an electronic device. The electronic device includes a light source system, a second optical system, and an imaging system. The second optical system includes a first prism and a first reflective element. The first prism includes a first face, a second face, and a third face that are adjacent to each other. The light source system provides light along a first optical path. The light penetrates the first prism and the fourth face of the first reflective element and then enters the fifth face of the first reflective element. After being reflected by the fifth face, the light penetrates the fourth face and the first prism in sequence and enters the target object along a second optical path. After being reflected by the target object, the light penetrates the third face and enters the second face. After being reflected by the second face, the light enters the first face along a fourth optical path. The light penetrates the first face and propagates to the imaging system. The first optical path and the fifth optical path have a fourth included angle, which is greater than 0 degrees and less than 45 degrees.

[0004] The aforementioned optical system is large in size, especially in the radial direction, which makes the equipment equipped with the optical system bulky and not conducive to handheld operation, thus adversely affecting the portability and applicability of the equipment.

[0005] Therefore, there is an urgent need for a more compact, efficient, and easy-to-hold optical system design to meet the miniaturization and portability requirements of modern medical devices and other precision instruments. Summary of the Invention

[0006] The present invention was made in view of the above-mentioned needs, and its purpose is to provide a digital dental impression instrument with a miniaturized optical system.

[0007] According to a first aspect of the present invention, an optical system is provided, comprising:

[0008] The optical path emission subsystem generates an optical path with patterned information and emits the optical path into the target object, such as the area to be collected inside the oral cavity.

[0009] A scanning mirror, used to reflect patterned light into a target and extract an image of the target; and

[0010] An image receiving and processing subsystem receives and processes images exported by the scanning mirror.

[0011] The optical transmission subsystem includes:

[0012] An illumination module that generates a light path, such as a monochromatic or multicolor light path;

[0013] An optical modulation module that imbues the optical path with patterned information; and

[0014] A curved prism is disposed between the illumination module and the light modulation module. The curved prism includes an incident surface, a reflection-transmission composite interface, and a curved surface coated with a reflective film. The curved prism is used to change the direction of the light path and focus the light path. The light path enters from the incident surface, is reflected by the reflection-transmission composite interface, is reflected and focused by the curved surface, and then exits from the reflection-transmission composite interface and enters the light modulation module at a specific angle.

[0015] In the above technical solutions, the term "pattern information" refers to various patterns such as stripes, codes, and array graphics, which can be compiled by computer programs into information such as audio, video, images, and text.

[0016] The term "optical modulation module" encompasses not only digital micromirror devices (DMDs) but also optical modulation elements such as gratings or LCD+HTPS (high-temperature polysilicon displays). The term "reflection-transmission composite interface" refers to an arrangement where a reflective film is coated at the first reflection position of the reflection-transmission composite interface, wherein the light-emitting surface is the light-transmitting surface, and the remaining surfaces are coated with reflective films to form reflective surfaces. This arrangement is limited to cases where the angle of incidence is less than the critical angle for total internal reflection. This arrangement is well known to those skilled in the art and will not be described further here.

[0017] By using curved prisms to replace traditional discrete optical components, such as lenses and mirrors, the spatial dimensions of the optical system can be significantly reduced, resulting in a miniaturized optical system that is more suitable for handheld instruments such as digital dental impression machines. Because curved prisms integrate the incident surface, the reflection-transmission interface, and the curved surface, and utilize a partially transparent surface with a partially reflective surface coated with a reflective film or possessing total internal reflection capabilities to change the direction of the light path, the entire optical path can be completed in a more compact space. Due to the multifaceted design of the curved prism, it can effectively fold the light path without sacrificing performance, which not only reduces the overall space occupied but also allows for a more compact arrangement of other components. In the optimized optical system, the illumination module, curved prism, light modulation module, and projection lens are arranged sequentially along the emission direction of the light path. The light path emitted from the illumination module to the curved prism and the light path emitted from the light modulation module through the projection lens to the scanning mirror roughly coincide in the radial direction, thereby reducing the spatial dimensions of the optical system in the radial direction and shrinking the radial dimensions of the enclosure of the optical system, contributing to the miniaturization of the device and facilitating handheld operation by staff.

[0018] Although the optical system described above is referred to as a digital dental impression device in the various embodiments of the specification, those skilled in the art should understand that the optical system can also be used in other three-dimensional imaging devices, such as dental implant surgery navigation and positioning devices, CBCT, facial scanning devices, etc.

[0019] Preferably, the reflection-transmission composite interface can have both a transparent surface and a reflective surface, i.e., part of the interface is a transparent surface and part of the interface is a reflective surface. Under this condition, the incident angle of the light path transmitted from the incident surface to the reflection-transmission composite interface is greater than the critical angle of total internal reflection of the curved prism, and the incident angle of the light path reflected from the curved surface and focused to the reflection-transmission composite interface is less than the critical angle of total internal reflection of the curved prism.

[0020] In this field, the aforementioned reflection-transmission composite interface can be achieved through various means. For example, a reflective film can be coated at or near the first reflection position of the reflection-transmission composite interface to serve as a reflective surface, while the uncoated portion of the interface serves as a transmitting surface. When the angle of incidence of the light path transmitted from the incident surface to the reflection-transmission composite interface is greater than the critical angle of total internal reflection of the curved prism, the light path is totally internally reflected onto the curved surface; when the angle of incidence of the light path reflected from the curved surface and focused onto the interface is less than the critical angle of total internal reflection of the prism, the light path is transmitted through the interface. Alternatively, the curved surface of the prism can be designed as a converging surface, so that the light path reflected from the interface to the surface is focused and reflected back to the interface.

[0021] In another embodiment of the invention, the optical path emitting subsystem further includes a projection lens for projecting the optical path of the pattern information onto the scanning mirror. The term "projection lens" refers not only to a single projection lens but also to a group of two or more projection lenses; all such variations should fall within the scope of protection of this invention.

[0022] In yet another embodiment of the present invention, the image receiving and processing subsystem may include:

[0023] A camera lens that focuses and shapes the optical path containing the image derived from the scanning mirror;

[0024] An image sensor module is used to process the image exported by the scanning mirror; and

[0025] A multifaceted reflecting prism is disposed between the camera lens and the image sensor module. The multifaceted reflecting prism is used to receive and reflect focused and shaped light. The multifaceted reflecting prism includes an incident surface, an exit surface, a first reflecting surface, and a second reflecting surface. The first and second reflecting surfaces are coated with reflective films. The light path enters the first reflecting surface through the incident surface, is reflected by the first reflecting surface to the second reflecting surface, is reflected by the second reflecting surface to the exit surface, and then exits from the exit surface.

[0026] Similarly, the term "camera lens" refers not only to a single camera lens, but also to a camera lens group consisting of two or more camera lenses, and these variations should all fall within the protection scope of this invention.

[0027] Preferably, the incident surface and the first reflecting surface can form a first included angle, the first reflecting surface and the second reflecting surface can form a second included angle, and the second reflecting surface and the emitting surface can form a third included angle. More specifically, the first included angle can be selected in the range of 15° to 75°, preferably 45°; the second included angle can be selected in the range of 15° to 150°, preferably 60°; and the third included angle can be selected in the range of 15° to 90°, preferably 45°.

[0028] By using a multi-faceted reflecting prism instead of a traditional mirror to reflect the image multiple times, the direction of light travel can be effectively adjusted, allowing the image to be reflected to the desired position. Furthermore, the sensor can be positioned between the projection lens and the camera lens. Based on the existing optical system of dental impression instruments, the radial arrangement of the optical system is further optimized, resulting in a smaller radial space occupied by the optical system. This helps to reduce the radial dimensions of the enclosure of the optical system, facilitating the handling and operation of the device.

[0029] In a preferred embodiment, the curved prism is implemented as a composite lens consisting of a triangular prism and a curved lens, wherein the curved lens constitutes the curved surface of the curved prism.

[0030] Preferably, the curved lens can be a spherical lens. However, the scope of protection of this invention is not limited to spherical lenses; other curved lenses that can achieve the same function are also included.

[0031] By breaking down complex curved prisms into standard triangular prisms and curved lenses, each component can be manufactured independently using mature processes. Triangular prisms and curved lenses are common components in optics, with mature and stable manufacturing processes that facilitate large-scale production and quality control. Replacing the more complex manufacturing process of curved prisms further reduces production difficulty.

[0032] In the optical path emission subsystem, the illumination module, curved prism, optical modulation module, and projection lens are arranged sequentially along the emission direction of the optical path. In this case, the incident surface faces the illumination module, the light emitted from the illumination module enters the curved prism through the incident surface, and the light path reaches the optical modulation module from the reflection-transmission composite interface.

[0033] In the image receiving and processing subsystem, the camera lens, the multifaceted prism, and the image sensor module are arranged sequentially along the reflection direction of the light path. In this case, the light path enters the multifaceted prism through the incident surface from the camera lens, and then exits through the exit surface to the image sensor module.

[0034] The second aspect of the invention relates to a dental digital impression apparatus equipped with an optical system as described in the first aspect of the invention.

[0035] When optical systems are used in digital dental impression systems, the target object is the oral cavity. Of course, when optical systems are used in other medical devices, the target object can also be other organs or tissues that require imaging examination.

[0036] Furthermore, a third aspect of the present invention provides an image acquisition method, comprising the following steps:

[0037] Using the optical system according to the first aspect of the present invention, the illumination module generates an optical path, which enters the light modulation module at a specific angle via a curved prism;

[0038] The optical modulation module receives the optical path and imbues it with pattern information.

[0039] The projection lens receives the light path containing the pattern information and projects it to the scanning mirror;

[0040] The scanning mirror reflects the light path carrying the pattern information to the target object and exports the image within the target object to the camera lens;

[0041] The camera lens focuses and shapes the light path containing the image exported by the scanning mirror, and then projects the light onto the image sensor module via a multi-faceted reflecting prism.

[0042] The image sensor module processes images.

[0043] By using curved prisms or compound lenses instead of the combination of mirrors and lenses in existing technologies, it can effectively fold the optical path without sacrificing performance. This not only reduces the overall space occupied but also allows other components to be arranged more compactly. In this way, the illumination module, curved prism, light modulation module, and projection lens will be roughly arranged in a straight line, reducing the radial space occupied by the optical path emission subsystem.

[0044] Furthermore, since a multi-faceted reflecting prism according to an embodiment of the present invention is used instead of a reflecting mirror in the prior art, the reflected light can be reflected along the inner side of the radial dental impression instrument, thereby allowing the image sensor module to be arranged between the camera lens and the projection lens, further reducing the radial space occupied by the optical system, which in turn helps to reduce the spatial size of the enclosure of the optical system and facilitates handheld operation. Attached Figure Description

[0045] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0046] Figure 1 is a schematic diagram of an optical system for a digital dental impression instrument according to the prior art;

[0047] Figure 2 is a schematic diagram of an optical system according to an embodiment of the present invention;

[0048] Figures 3A and 3B are respectively a side view and a perspective view of a first embodiment of a curved prism in an optical system according to an embodiment of the present invention.

[0049] Figures 4A and 4B are respectively a side view and a perspective view of a second embodiment of a curved prism in an optical system according to an embodiment of the present invention.

[0050] Figure 5A is a perspective view of a multifaceted reflecting prism in an optical system according to an embodiment of the present invention;

[0051] Figure 5B shows the reflective film coated on the multifaceted reflective prism in Figure 5A;

[0052] Figure 6 is a schematic diagram comparing an optical system according to an embodiment of the present invention with an optical system of the prior art;

[0053] Figure 7 is a schematic diagram comparing the radial length of an optical system according to an embodiment of the present invention with that of a prior art optical system;

[0054] Figure 8 is a schematic diagram of an image acquisition method of an optical system according to an embodiment of the present invention.

[0055] List of reference numerals: 1. Illumination module; 2. First reflector; 3. First lens; 4. Light modulation module; 41. Digital micromirror element; 42. DMD controller; 5. Projection lens; 6. Scanning reflector; 7. Camera lens; 8. Second reflector; 9. Image sensor module; 21. Curved prism; 21A. Light-incident surface; 21B. Reflection-transmission composite interface; 21C. Curved surface; 22. Triangular prism; 23. Curved lens; 81. Multifaceted reflection prism; 81A. Light-incident surface; 81B. Light-out surface; 81C. First reflecting surface; 81D. Second reflecting surface; 100. Orifice. H1, H2. Radial distances. Detailed Implementation

[0056] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present application.

[0057] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate to understand the embodiments described in this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0058] In this application, the terms "upper," "lower," "front," "rear," etc., indicate directions or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0059] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain circumstances to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances.

[0060] Furthermore, the terms "installation," "setting up," and "arrangement" should be interpreted broadly. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0061] Furthermore, the term "gluing" as used in this application should be understood as any method capable of providing sufficient strength and durability, such as the process of permanently or semi-permanently joining two or more elements together using adhesives, bonding materials, or other similar means. The term "radial" as used in this application refers to a direction generally perpendicular to the longer side of the device.

[0062] It should be noted that, where there is no conflict, the embodiments and features described in this application can be combined with each other. To make the solution of the present invention clearer, the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0063] Figure 1 is a schematic diagram of an optical system for a digital dental impression apparatus in the prior art. This optical system typically includes a light-emitting subsystem, a scanning mirror, and an image receiving and processing subsystem. As shown in Figure 1, the light-emitting subsystem includes an illumination module 1, a first emitting mirror 2, a first lens 3, a light modulation module 4, and a projection lens 5. The image receiving and processing subsystem includes a camera lens 7, a second mirror 8, and an image sensor module 9. The illumination module 1, the first mirror 2, the first lens 3, the light modulation module 4, the projection lens 5, and the scanning mirror 6 are arranged sequentially along the light-emitting direction, which is the direction in which the light path travels through the aforementioned optical elements, indicated by solid arrows in Figure 1. The scanning mirror 6, the camera lens 7, the second mirror 8, and the image sensor module 9 are arranged sequentially along the light-reflection direction, which is the direction in which the light path containing the image derived from the scanning mirror 6 travels through the aforementioned optical elements, indicated by dashed arrows in Figure 1. The image sensor module 9 is positioned above the second reflector 8, and the light path emitted from the illumination module 1 to the first reflector 2 and the light path emitted from the light modulation module 4 to the scanning reflector 6 via the projection lens 5 have a large spatial distance in the radial direction. As a result, the illumination module 1, the first reflector 2, the light modulation module 4, and the projection lens 5 occupy a large space in the radial direction.

[0064] Figure 2 is a schematic diagram of an optical system for a digital impression apparatus for the oral cavity according to an embodiment of the present invention. This optical system also includes a light path emitting subsystem, a scanning mirror 6, and an image receiving and processing subsystem. As shown in Figure 2, the light path emitting subsystem generates a light path with pattern information and emits this light path to the scanning mirror 6. The scanning mirror 6 is used to reflect the light path with pattern information onto the target object, i.e., the oral cavity 100 or the area to be acquired within the oral cavity, and to export an image of the target object. The image receiving and processing subsystem receives and processes the image exported by the scanning mirror 6, i.e., the image of the target object. The light path emitting subsystem includes: an illumination module 1, a curved prism 21, a light modulation module 4, and a projection lens 5. The illumination module 1 generates the light path. The light modulation module 4 preferably employs a DMD module, including: a digital micromirror element 41, which integrates a large number of independently controllable mirror arrays for receiving the incident light path and reflecting the light path with pattern information at a certain angle; and a DMD controller 42, which controls the movement of the mirror array within the digital micromirror element 41. The projection lens 5 is used to project the light path with pattern information onto the scanning mirror 6.

[0065] Figures 3A and 3B illustrate a curved prism 21 in an optical system according to an embodiment of the present invention. As shown in Figure 3B, the curved prism 21 includes an incident light surface 21A, a reflection-transmission composite interface 21B, and a curved surface 21C coated with a reflective film. The curved prism 21 is disposed between the light modulation module 4 and the illumination module 1.

[0066] The light emitted from the illumination module 1 enters the curved prism 21 through its incident surface 21A. Inside the curved prism 21, the light undergoes two reflections, exits through the reflection-transmission composite interface 21B, and then enters the light modulation module 4. Specifically, the curved prism 21 is used to change the direction of the light path and focus it. After entering from the incident surface 21A, the light is reflected by the reflection-transmission composite interface 21B, then reflected again by the curved surface 21C and focused, before exiting from the reflection-transmission composite interface 21B and entering the light modulation module 4 at a specific angle.

[0067] It should be noted that the reflection-transmission composite interface 21B has a light-transmitting surface and a reflective surface. The incident angle of the light path transmitted from the incident surface 21A to the reflection-transmission composite interface 21B needs to be greater than the critical angle of total internal reflection of the curved prism 21, so that total internal reflection occurs at the reflection-transmission composite interface 21B. The incident angle of the light path reflected from the curved surface 21C and focused to the reflection-transmission composite interface 21B needs to be less than the critical angle of total internal reflection of the curved prism 21, so that the light path that reaches the reflection-transmission composite interface 21B again can completely exit the reflection-transmission composite interface 21B.

[0068] The curved surface 21C of the curved prism 21 is preferably a light path converging surface, so that the light path reflected from the reflection-transmission composite interface 21B to the curved surface 21C is focused and reflected back to the reflection-transmission composite interface 21B.

[0069] Returning to Figure 2, in the optical path emission subsystem, the illumination module 1, curved prism 21, light modulation module 4, projection lens 5, and scanning mirror 6 are arranged sequentially along the emission direction of the optical path. In the image receiving and processing subsystem, the camera lens 7, multifaceted reflection prism 81, and image sensor module 9 are arranged sequentially along the reflection direction of the optical path. The image sensor module 9 is positioned between the camera lens 7 and the projection lens 5, and the optical path emitted from the illumination module 1 to the curved prism 21 and from the light modulation module 4 to the scanning mirror 6 via the projection lens 5 are approximately coincident in the radial direction. That is, the illumination module 1, curved prism 21, light modulation module 4, and projection lens 5 occupy a relatively small space in the radial direction. Therefore, this invention utilizes the curved prism 21 instead of the combination of the first reflection mirror 2 and the first lens 3 in the prior art, which further facilitates the integration of various components of the optical system and promotes the miniaturization of the dental digital impression instrument.

[0070] Alternatively, as shown in Figures 4A and 4B, the curved prism 21 can also be implemented as a compound lens composed of a triangular prism 22 and a curved lens 23. Since the curved surface of the curved prism 21 is difficult and costly to manufacture in actual production, the embodiments shown in Figures 4A and 4B provide another solution that achieves the same technical effect and replaces the curved prism 21. It can be seen that the curved lens 23 of the compound lens is bonded to the lower surface of the triangular prism 22, for example, by cementing or other means, and the light path can pass through the cemented surface of both the curved lens 23 and the triangular prism 22. Moreover, the curved lens 23 of this compound lens has the same curvature as the curved surface 21C of the curved prism 21 shown in Figure 3, thereby achieving the same optical effect as the curved prism 21. Therefore, the curved lens 23 of the compound lens can replace the curved surface 21C of the curved prism 21.

[0071] In addition, the light-incident surface 21A and the reflection-transmission composite interface 21B of the compound lens are identical to those of the curved prism 21. Since the triangular prism 22 and the curved lens 23 are more common in practical applications and are easier to manufacture, manufacturing costs can be saved while achieving the same optical effect.

[0072] In both of the above embodiments, whether it is the curved prism 21 or the composite lens composed of the triangular prism 22 and the curved lens 23, their light-incident surfaces 21A face the illumination module 1. The light path emitted from the illumination module 1 enters the curved prism 21 through the light-incident surface 21A, is reflected by the reflection-transmission composite interface 21B of the curved prism 21 to the curved surface 21C, and then is reflected back to the reflection-transmission composite interface 21B through the curved surface 21C. Finally, the light path enters the light modulation module 4 through the reflection-transmission composite interface 21B.

[0073] Figures 5A and 5B illustrate a multifaceted reflection prism 81 in an optical system according to an embodiment of the present invention. The multifaceted reflection prism 81 receives and reflects light that has been focused and shaped by a camera lens 7. As shown in Figure 5A, the multifaceted reflection prism 81 includes an incident surface 81A, an exit surface 81B, a first reflecting surface 81C, and a second reflecting surface 81D. As shown in Figure 5B, the first reflecting surface 81C and the second reflecting surface 81D are coated with reflective films for reflecting the light path, thereby changing the direction of the light path within the multifaceted reflection prism 81.

[0074] An incident light surface 81A and a first reflecting surface 81C form a first included angle, the first reflecting surface 81C and a second reflecting surface 81D form a second included angle, and the second reflecting surface 81D and an emitting light surface 81B form a third included angle. In a preferred embodiment, the first included angle is 15° to 75°, the second included angle is 15° to 150°, and the third included angle is 15° to 90°. In a most preferred embodiment, the first included angle is 45°, the second included angle is 60°, and the third included angle is 45°. The above numerical ranges were obtained by the inventors of this application through numerous experiments, and the technical effects are progressively enhanced.

[0075] Returning to Figure 2, since the scanning mirror 6, camera lens 7, and multifaceted reflecting prism 81 are arranged sequentially along the light path reflection direction, the light path focused and shaped by the camera lens 7 enters the multifaceted reflecting prism 81 through the light-incident surface 81A, is reflected by the first reflecting surface 81C to the second reflecting surface 81D, is reflected by the second reflecting surface 81D to the light-exiting surface 81B, and finally leaves the multifaceted reflecting prism 81 from the light-exiting surface 81B and enters the image sensor module 9.

[0076] By using a multifaceted reflecting prism 81 instead of the second reflecting mirror 8 in the prior art, the direction of light propagation in the prior art can be changed, making the light emitted from the multifaceted reflecting prism 81 more focused towards the center of the digital dental impression instrument. As shown in Figure 6, the optical system according to the present invention is located above Figure 6, while the optical system in the prior art is located below Figure 6. By comparison, it can be seen that the image sensor module in the optical system according to the present invention can be arranged radially inwards, allowing the image sensor module to be arranged between the projection lens and the camera lens. This further facilitates the integrated arrangement of various modules in the optical system, reduces the radial dimension of the optical system, facilitates holding and operation, and contributes to the miniaturization of the digital dental impression instrument.

[0077] To illustrate the miniaturization of the optical system for a digital dental impression apparatus according to the present invention, Figure 7 shows a comparative schematic diagram of the optical system according to an embodiment of the present invention and a prior art optical system, wherein the optical system according to the embodiment of the present invention is located above Figure 7, and the prior art optical system is located below Figure 7. In practical use, the optical system needs to be enclosed in a housing for handheld operation by staff.

[0078] As shown in Figure 7, the radial dimension of the optical system in the prior art is H2, occupying a large space in the radial direction. Compared with the prior art, the optical system according to the present invention uses a curved prism instead of the combination of a mirror and a lens in the prior art, making the illumination module, curved prism, light modulation module, and projection lens roughly linearly distributed, reducing the radial space occupied by the light path emission subsystem. Furthermore, because a multi-faceted reflecting prism is used in the optical system according to the present invention instead of the second reflecting mirror in the prior art, the reflected light path can be reflected radially towards the inner side of the optical system, allowing the image sensor module to be arranged radially towards the inner side of the optical system, and thus allowing the image sensor module to be arranged between the camera lens and the projection lens. This further reduces the radial space occupied by the optical system, which in turn helps to reduce the radial size of the enclosure of the optical system, facilitating gripping and operation. As shown in Figure 7, the radial distance H1 of the optical system according to the embodiment of the present invention is significantly smaller than the radial distance H2 of the optical system in the prior art.

[0079] The present invention also provides an image acquisition method using an optical system according to the present invention. As shown in FIG8, the method includes the following steps:

[0080] The lighting module 1 generates a monochromatic or multicolor light path, which enters the curved prism 21 through the light incident surface 21A;

[0081] After entering the curved prism 21, the light path is incident on the light-emitting surface 21B of the curved prism 21, and is reflected by the light-emitting surface 21B to the curved surface 21C. Since the curved surface 21C is coated with a reflective film, the light path is reflected again by the curved surface 21C to the light-emitting surface 21B, and exits to the light modulation module 4 at the incident angle required by the light modulation module 4.

[0082] After receiving the optical path, the optical modulation module 4 controls the mirror array in the digital micromirror element 41 via a controller such as the DMD controller 42, so that the optical path carries specific pattern information and finally emits it to the projection lens 5.

[0083] The light path carrying the pattern information is received by the projection lens 5 and projected onto the scanning mirror 6 via the projection lens 5;

[0084] The scanning mirror 6 reflects the light path carrying the pattern information to the target object, namely the oral cavity or the area to be collected 100 inside the oral cavity;

[0085] The image of the target object is exported to the camera lens 7. The camera lens 7 focuses and shapes the light path containing the image exported by the scanning mirror 6, and finally projects it onto the multifaceted reflection prism (81) via the multifaceted reflection prism (81).

[0086] The image of the target object enters the multi-faceted reflection prism 81 through the light-incident surface 91A, is reflected by the first reflection surface 81C to the second reflection surface 81D, and is reflected by the second reflection surface 81D to the light-out surface 81B, and finally enters the image sensor module 9.

[0087] The image sensor module 9 receives and processes images of the area 100 to be acquired within the oral cavity.

[0088] The implementation of this invention is not limited to the embodiments described above, and can be adjusted and optimized according to different design requirements and usage environments. The scope of protection of this invention should be determined by the content of the claims, and not limited to the embodiments described above. Although this invention has been described through specific embodiments, any modifications, changes, and combinations made by those skilled in the art to the various embodiments and implementation methods of this invention without departing from the spirit of this invention should be within the scope of protection of this invention.

Claims

1. An optical system, comprising: An optical path emission subsystem generates an optical path with patterned information and emits the optical path into the target object; A scanning mirror (6) is used to reflect the light path with pattern information into the target object and export an image of the target object; as well as An image receiving and processing subsystem receives and processes the image exported by the scanning mirror (6). The optical path transmission subsystem includes: Lighting module (1), which generates an optical path; An optical modulation module (4) that enables the optical path to carry the pattern information; and A curved prism (21) is disposed between the lighting module (1) and the light modulation module (4). The curved prism (21) includes an incident surface (21A), a reflection-transmission composite interface (21B), and a curved surface (21C) coated with a reflective film. The curved prism (21) is used to change the direction of the light path and focus the light path. The light path enters from the incident surface (21A), is reflected by the reflection-transmission composite interface (21B), is reflected and focused by the curved surface (21C), and then exits from the reflection-transmission composite interface (21B) and enters the light modulation module (4) at a specific angle.

2. The optical system as described in claim 1, characterized in that, The reflection-transmission composite interface (21B) has a light-transmitting surface and a reflective surface. The incident angle of the light path transmitted from the incident surface (21A) to the reflection-transmission composite interface (21B) is greater than the critical angle of total internal reflection of the curved prism (21). The incident angle of the light path reflected from the curved surface (21C) and focused onto the reflection-transmission composite interface (21B) is less than the critical angle of total internal reflection of the curved prism (21).

3. The optical system as described in claim 1, characterized in that, The curved surface (21C) of the curved prism (21) is a light path converging surface. The light path reflected from the reflection-transmission composite interface (21B) to the curved surface (21C) is focused and then reflected back to the reflection-transmission composite interface (21B).

4. The optical system as claimed in claim 1, characterized in that, The curved prism (21) is implemented as a composite lens composed of a triangular prism (22) and a curved lens (23), wherein the curved lens (23) constitutes the curved surface (21C) of the curved prism (21).

5. The optical system as claimed in claim 1, characterized in that, The optical path emission subsystem also includes a projection lens (5), which is used to project the optical path with pattern information onto the scanning mirror (6).

6. The optical system as claimed in claim 5, characterized in that, In the optical path emission subsystem, the illumination module (1), the curved prism (21), the light modulation module (4), and the projection lens (5) are arranged sequentially along the emission direction of the optical path.

7. The optical system as claimed in claim 1, characterized in that, The image receiving and processing subsystem includes: Camera lens (7) focuses and shapes the optical path containing the image derived from the scanning mirror (6); Image sensor module (9), the image sensor module (9) being used to process the image exported by the scanning mirror (6); and A multifaceted reflection prism (81) is disposed between the camera lens (7) and the image sensor module (9). The multifaceted reflection prism (81) is used to receive and reflect focused and shaped light. The multifaceted reflection prism (81) includes an incident surface (81A), an exit surface (81B), a first reflecting surface (81C), and a second reflecting surface (81D). The first reflecting surface (81C) and the second reflecting surface (81D) are coated with reflective films. The light path enters the first reflecting surface (81C) through the incident surface (81A), is reflected by the first reflecting surface (81C) to the second reflecting surface (81D), and is then reflected by the second reflecting surface (81D) to the exit surface (81B) before exiting from the exit surface (81B).

8. The optical system as claimed in claim 7, characterized in that, The light-incident surface (81A) and the first reflective surface (81C) form a first included angle, the first reflective surface (81C) and the second reflective surface (81D) form a second included angle, and the second reflective surface (81D) and the light-emitting surface (81B) form a third included angle.

9. The optical system as claimed in claim 8, characterized in that, The first included angle is 15° to 75°, the second included angle is 15° to 150°, and the third included angle is 15° to 90°.

10. The optical system as claimed in claim 9, characterized in that, The first included angle is 45°, the second included angle is 60°, and the third included angle is 45°.

11. The optical system as claimed in claim 7, characterized in that, In the image receiving and processing subsystem, the camera lens (7), the multifaceted reflection prism (81), and the image sensor module (9) are arranged sequentially along the reflection direction of the optical path.

12. A dental digital impression apparatus equipped with an optical system as described in any one of claims 1 to 11.

13. The digital dental impression instrument as described in claim 12, characterized in that, The target object is the oral cavity (100).

14. An image acquisition method, comprising the following steps: Using the optical system as described in any one of claims 1 to 11, the illumination module (1) generates an optical path that enters the light modulation module (4) at a specific angle via the curved prism (21); The optical modulation module (4) receives the optical path and enables the optical path to carry pattern information; The projection lens (5) receives the light path with pattern information and emits it to the scanning mirror (6); The scanning mirror (6) reflects the light path with pattern information into the target object and exports the image inside the target object to the camera lens (7); The camera lens (7) focuses and shapes the light path containing the image exported by the scanning mirror (6), and emits it to the image sensor module (9) via the multifaceted reflection prism (81); The image sensor module (9) processes the image.

Images