Optical path system and oral digital impression instrument using the same

Abstract

An optical path system applied to a digital dental impression instrument, comprising an optical path emitting subsystem, a scanning head mirror and at least one image receiving and processing subsystem, the optical path emitting subsystem comprising a projection lens for projecting the optical path of a light source to the scanning head mirror, the image receiving and processing subsystem comprising: a camera lens for receiving the image of a target object reflected by the scanning head mirror; and an image sensor module for receiving and processing the image of the target object, the optical axis of the projection lens is OA1 and the field of view center line is L1, the optical axis of the camera lens is OA2 and the field of view center line is L2, the field of view center line of the camera lens of the at least one image receiving and processing subsystem is offset from the optical axis, the field of view center line of the projection lens and the field of view center line of the camera lens form a parallax angle, and the angle between the optical axis of the projection lens and the optical axis of the camera lens is 0° to the parallax angle. The volume of the digital dental impression instrument can be effectively reduced, and the optical and mechanical structure features are more regular.

Description

TECHNICAL FIELD

[0001] The present application relates to an optical path system and an oral digital impression instrument using the same. BACKGROUND

[0002] The oral digital impression instrument (oral scanner) is a portable 3D scanning device used in the field of dentistry, which can quickly obtain a high-precision three-dimensional digital model of the structure of teeth, gums and other structures in the patient's mouth. The core technology of the oral scanner three-dimensional image acquisition includes structured light technology and stereo vision technology.

[0003] The structured light technology or stereo vision technology generally needs parallax to obtain the phase information of the feature, and the three-dimensional image is reconstructed through the phase information. The optical path of the structured light is generally one camera optical path and one projection optical path, and the stereo vision is two camera optical paths. The formation of parallax needs to form a certain angle between the two optical paths. The traditional parallax scheme is to form a specific angle between the optical axes of the two optical paths. When using the optical axis to form parallax, the image is in the center of the optical path. However, since the two optical paths are relatively inclined, the overall structure size will be larger if a sensor or other device is added to the rear section of the optical path, which is not suitable for application in the miniaturization of the oral scanner. Therefore, a new optical path system is expected to obtain a high-precision three-dimensional digital model and realize the miniaturization of the oral digital impression instrument. SUMMARY

[0004] The present application is made to solve the above technical problems, and the purpose is to provide an optical path system and an oral digital impression instrument using the same, which is different from the prior art using the optical axis to form the parallax angle, using the field of view offset of the optical path to form the parallax angle, which can effectively reduce the volume of the oral digital impression instrument, and the optical and mechanical structure features are more regular.

[0005] The first mode of the present application relates to an optical path system applied to a digital dental impression instrument, the optical path system comprising an optical path emitting subsystem, a scanning head mirror and at least one image receiving and processing subsystem, the optical path emitting subsystem comprising a projection lens for projecting an optical path of a light source to the scanning head mirror, the scanning head mirror being arranged opposite to a window of a scanning head housing of the digital dental impression instrument, the optical path projected by the projection lens being reflected to a target object, the image receiving and processing subsystem comprising a camera lens receiving an image of the target object reflected via the scanning head mirror and an image sensor module receiving and processing the image of the target object, an optical axis of the projection lens being OA1 and a field of view center line of the projection lens being L1, an optical axis of the camera lens being OA2 and a field of view center line of the camera lens being L2, the field of view center line of the camera lens of the at least one image receiving and processing subsystem being offset from the optical axis of the camera lens, the field of view center line of the projection lens and the field of view center line of the camera lens forming a parallax included angle, and an included angle between the optical axis of the projection lens and the optical axis of the camera lens being set as 0°≤ the included angle between the optical axis of the projection lens and the optical axis of the camera lens ≤ the parallax included angle.

[0006] According to the optical path system of the structure, the field of view center line of the camera lens of the at least one image receiving and processing subsystem is offset from the optical axis of the camera lens, the field of view center line of the projection lens and the field of view center line of the camera lens form a parallax included angle, and the included angle between the optical axis of the projection lens and the optical axis of the camera lens is set as 0°≤ the included angle between the optical axis of the projection lens and the optical axis of the camera lens ≤ the parallax included angle, i.e. parallel or forming an included angle. Different from the prior art using the optical axis to form a parallax included angle, but using the field of view offset of the optical path to form a parallax included angle, the volume of the digital dental impression instrument can be effectively reduced, and the optical and mechanical structure features are more regular.

[0007] As a preferred mode, the field of view center line of the projection lens is offset from the optical axis of the projection lens, and the field of view center line of the projection lens and the field of view center line of the camera lens form a parallax included angle.

[0008] According to the structure, the projection lens is also arranged with the field of view center line offset from the optical axis of the projection lens, the field of view offset of the optical path can be further effectively utilized to form a parallax included angle, so that the volume of the digital dental impression instrument can be further effectively reduced.

[0009] As another preferred mode, the field of view center line of the projection lens coincides with the optical axis of the projection lens, and the field of view center line of the projection lens and the field of view center line of the camera lens form a parallax included angle.

[0010] According to the structure, the projection lens adopts the structure that the field center line is coincident with the optical axis in the prior art, so that the difficulty of optical path design can be reduced and the design time can be saved.

[0011] In addition, as the image receiving processing subsystem, the optical path system comprises a first image receiving processing subsystem and a second image receiving processing subsystem, the first image receiving processing subsystem comprises a first camera lens and a first image sensor module, the second image receiving processing subsystem comprises a second camera lens and a second image sensor module, an optical axis of the first camera lens is OA21, a field center line of the first camera lens is L21, an optical axis of the second camera lens is OA22, a field center line of the second camera lens is L22, the field center line of the first camera lens is offset from the optical axis of the first camera lens, the field center line of the second camera lens is offset from the optical axis of the second camera lens, a parallax angle is formed between the field center line of the projection lens and the field center line of the first camera lens, and a parallax angle is formed between the field center line of the projection lens and the field center line of the second camera lens.

[0012] According to the structure, as the image receiving processing subsystem, two systems, i.e. the first image receiving processing subsystem and the second image receiving processing subsystem, are provided, the field center lines of the camera lenses of the two image receiving processing subsystems are offset from the optical axes of the camera lenses, and the volume of the digital dental impression instrument can be effectively reduced while the multi-optical path structure is realized.

[0013] Preferably, the parallax angle is set to be in the range of 6° to 10°.

[0014] According to the structure, by setting the parallax angle to be in the range of 6° to 10°, the accurate construction of the three-dimensional image can be realized.

[0015] Preferably, as the light source, the optical path emitting subsystem comprises an illumination module, the illumination module generates an optical path, the optical path emitting subsystem further comprises an optical path adjusting element and a light modulation module, the optical path adjusting element emits the optical path generated by the illumination module to the light modulation module at a required incident angle, the light modulation module is used for receiving the incident optical path and reflecting the incident optical path at a certain angle, and the projection lens is used for projecting the optical path reflected by the light modulation module to the scanning head mirror.

[0016] According to the structure, the effect of the present application can be realized in the DMD projection structure, i.e. the parallax angle is formed by using the field offset of the optical path, and the volume of the digital dental impression instrument can be effectively reduced.

[0017] Further, the light path adjusting element includes a first mirror and a first lens, the first mirror emits the light path generated by the illumination module to the light modulation module at a required incident angle via the first lens, and the first lens reflects the light path modulated by the light modulation module to the projection lens at a certain angle.

[0018] According to the structure, a specific way of the light path adjusting element is provided, the first mirror and the first lens cooperate to emit the light path generated by the illumination module to the light modulation module at a required incident angle.

[0019] Preferably, the scanning head mirror is arranged to rotate within a specified angle range by an angle adjusting device.

[0020] By arranging the scanning head mirror to rotate within a specified angle range by an angle adjusting device, the adjacent surface that is difficult to scan due to space limitation can be easily scanned. Further, the scanning head does not need to be moved greatly during scanning, and the scanning distance can be ensured to have no large deviation, so that high-quality image data of the adjacent surface can be obtained.

[0021] The second mode of the present application relates to a digital dental impression device, including a light path system.

[0022] According to the structure of the digital dental impression device, instead of using the optical axis to form a parallax angle as in the prior art, the field of view of the light path is used to form a parallax angle, which can effectively reduce the size of the digital dental impression device, and the optical and mechanical structure is more regular.

[0023] The third mode of the present application relates to a digital dental impression device, including: a light path system; and a light path system forming a parallax angle between the optical axis of the projection lens and the optical axis of the camera lens.

[0024] According to the structure of the digital dental impression device, the light path system forming a parallax angle by field of view offset and the light path system forming a parallax angle by optical axis can be used comprehensively, and the difficulty of light path design and the size of the digital dental impression device are balanced. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a diagram showing the structure of the light path system of the first embodiment of the present application.

[0026] Figure 2 is a schematic diagram showing the light ray propagation path of the light path system of the first embodiment of the present application.

[0027] Figure 3 is a simplified schematic diagram showing the light ray propagation path of the light path system of the first embodiment of the present application.

[0028] Figure 4 is a schematic diagram showing the light ray propagation path of the optical path system of the second embodiment of the present application.

[0029] Figure 5 is a schematic diagram showing the light ray propagation path of the optical path system of the prior art.

[0030] Figure 6 is a simplified schematic diagram showing the light ray propagation path of the optical path system of the prior art.

[0031] (Symbol explanation)

[0032] 1 illumination module;

[0033] 2 first mirror;

[0034] 3 first lens;

[0035] 4 light modulation module;

[0036] 5 projection lens;

[0037] 6 scan head housing;

[0038] 7 scan head mirror;

[0039] 8 target object;

[0040] 9 camera lens;

[0041] 10 image sensor module;

[0042] 91 first camera lens;

[0043] 92 second camera lens;

[0044] 101 first image sensor module;

[0045] 102 second image sensor module;

[0046] ES optical path emission subsystem;

[0047] RS image reception processing subsystem;

[0048] RS1 first image reception processing subsystem;

[0049] RS2 second image reception processing subsystem. DETAILED DESCRIPTION

[0050] In order to more clearly illustrate the technical solutions of the present application, the specific embodiments of the present application will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and other embodiments can also be obtained.

[0051] For the sake of simplicity of the drawings, only the parts related to the present application are shown in each drawing, which do not represent the actual structure of the product. In addition, in order to make the drawings simple and easy to understand, in some drawings, only one of the components with the same structure or function is shown schematically, or only one of them is marked. In this document, "one" not only means "only one", but also means "more than one" situation.

[0052] In addition, in this application, the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear" and the like are based on the positions or relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to indicating the orientation or positional relationship, the above-mentioned terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain attachment relationship or connection relationship in some cases. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances.

[0053] (First embodiment)

[0054] First, with reference to Figures 1 to 3 The general structure of the optical path system of the oral digital impression instrument of the first embodiment of the present application will be described. In order to facilitate description, the front-rear direction of the axial direction of the oral digital impression instrument is set as the X direction, the radial direction of the oral digital impression instrument is set as the Y direction, and the direction perpendicular to X and Y is set as the Z direction. In addition, in the present application, the DMD projection structure is taken as an example for description.

[0055] As shown in Figure 1 and Figure 2 The optical path system of the oral digital impression instrument generally includes an optical path emission subsystem ES, a scanning head mirror 7, and an image receiving and processing subsystem RS.

[0056] The light path emitting subsystem includes an illumination module 1 as a light source, a first 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 9 and an image sensor module 10. The illumination module 1, the first mirror 2, the first lens 3, the light modulation module 4, the projection lens 5, and the scanning head mirror 7 are sequentially arranged along a light path emitting direction, which is a direction in which a light path passes through the above-mentioned optical elements, and is indicated by a solid arrow in Figure 1 . The scanning head mirror 7, the camera lens 9, and the image sensor module 10 are sequentially arranged along a light path reflecting direction, which is a direction in which a light path containing an image derived by the scanning head mirror 7 passes through the above-mentioned optical elements, and is indicated by a dashed arrow in Figure 1 .

[0057] The scanning head mirror 7 is installed inside the scanning head housing 6 opposite the window M, and as a preferred mode, the scanning head mirror 7 is arranged to be rotatable within a prescribed angle range by an angle adjustment device (not shown).

[0058] Figure 2 is a schematic diagram showing a light ray propagation path of the light path system of the first embodiment of the present application, and the scanning head housing 6 and the like are omitted in order to clearly show the light ray propagation path.

[0059] As described above, the light path emitting subsystem includes the illumination module 1, the first mirror 2, the first lens 3, the light modulation module 4, and the projection lens 5. The illumination module 1 generates a light path with pattern information. The first mirror 2 and the first lens 3 constitute a light path adjustment element, and emit the light path generated by the illumination module 1 to the light modulation module 4 at an incident angle required by the light modulation module 4. The light modulation module 4 preferably employs a DMD module, which includes a digital micromirror element, in which a large number of independently controllable mirror arrays are integrated, for receiving an incident light path and reflecting a light path with pattern information at a certain angle, and a DMD controller for controlling the movement of the mirror arrays in the digital micromirror element. The projection lens 5 is used to project the light path with pattern information to the scanning head mirror 7. The scanning head mirror 7 is used to reflect the light path with pattern information to the target object 8, such as the oral cavity or a region to be captured in the oral cavity, and derive an image in the target object.

[0060] The image receiving and processing subsystem includes the camera lens 9 and the image sensor module 10. The camera lens 9 receives an image of the target object 8 reflected via the scanning head mirror 7, focuses and shapes the light path of the image, and then emits the light path to the image sensor module 10. The image sensor module 10 receives and processes the image of the target object 8.

[0061] As Figure 2As shown, the optical axis of the projection lens 5 is OA1, the field center line is L1, the optical axis of the camera lens 9 is OA2, the field center line is L2, and the angle between the field center line L1 of the projection lens 5 and the field center line L2 of the camera lens 9 is the parallax angle θ. The field center line L1 of the projection lens 5 is offset from the optical axis OA1, and the field center line L2 of the camera lens 9 is also offset from the optical axis OA2.

[0062] In the present application, the parallax angle θ is set to a range of 6° to 10°. By thus setting, as shown in FIG. 6, the width of the optical path system in the radial direction of the dental digital impression device can be reduced to about 21 mm. Figure 3

[0063] Figure 5 is a schematic diagram showing the light ray propagation path of the optical path system of the prior art. In the prior art, the optical axis of the projection lens and the field center line coincide, and the optical axis of the camera lens and the field center line also coincide. In the case of forming a parallax angle equivalent to the present application, as shown in FIG. 5, the width of the optical path system in the radial direction of the dental digital impression device is about 23 mm. Figure 6

[0064] Unlike the prior art which uses the optical axis to form a parallax angle, the present application uses the field offset of the optical path to form a parallax angle. In the present application, the field center line and the optical axis do not coincide, and the optical axes of the two optical paths are parallel, but by the offset of the field center line, a suitable parallax angle can be equipped. According to the optical path system of the dental digital impression device of the above structure, the volume of the dental digital impression device can be effectively reduced, and the optical mechanical structure feature is more regular.

[0065] (Second Embodiment)

[0066] Next, the general structure of the optical path system of the dental digital impression device of the second embodiment of the present application will be described with reference to Figure 4 The general structure of the optical path system of the dental digital impression device of the second embodiment of the present application will be described. In the second embodiment, the same symbols are used for the same parts as in the first embodiment and detailed description is omitted, and mainly the parts different from the first embodiment will be described in detail, and the other parts are referred to the description of the first embodiment.

[0067] Figure 4 is a schematic diagram showing the light ray propagation path of the optical path system of the second embodiment of the present application. As shown in FIG. 8, in this second embodiment, two sets of image receiving and processing subsystems, i.e., the first image receiving and processing subsystem RS1 and the second image receiving and processing subsystem RS2, are provided, and a plurality of optical paths are formed by the two sets of image receiving and processing subsystems and one set of optical path emitting subsystem. Figure 4

[0068] ​​​The first image receiving and processing subsystem RS1 includes a first camera lens 91 and a first image sensor module 101. The first camera lens 91 receives the image of the target object 8 reflected by the scan head mirror 7, focuses and shapes the light path of the image, and then enters the first image sensor module 101. The first image sensor module 101 receives and processes the image of the target object 8.

[0069] The second image receiving and processing subsystem RS2 includes a second camera lens 92 and a second image sensor module 102. The second camera lens 92 receives the image of the target object 8 reflected by the scan head mirror 7, focuses and shapes the light path of the image, and then enters the second image sensor module 102. The second image sensor module 102 receives and processes the image of the target object 8.

[0070] As shown in Figure 4 , the optical axis of the projection lens is OA1, and the field of view center line is L1. The field of view center line L1 of the projection lens 5 coincides with the optical axis OA1. The optical axis of the first camera lens 91 is OA21, and the field of view center line is L21. The angle between the field of view center line L1 of the projection lens 5 and the field of view center line L21 of the first camera lens 91 is the parallax angle θ. The optical axis of the second camera lens 92 is OA22, and the field of view center line is L22. The angle between the field of view center line L1 of the projection lens 5 and the field of view center line L22 of the second camera lens 92 is the parallax angle θ.

[0071] In the present application, the parallax angle θ is set to a range of 6° to 10°. By setting it in this way, the width of the light path system in the radial direction of the dental digital impression device can be reduced as shown in Figure 3

[0072] The above describes embodiments of the present application, but it should be understood that the present disclosure is not limited to the above-described embodiments, structures. The present disclosure also includes various modifications, modifications within the scope of equivalents. In addition, various combinations, modes, and further combinations, modes containing only one element, more than or less than them, are within the scope and range of the present disclosure.

[0073] For example, in the above-described embodiments, the present application is described by taking the DMD projection structure as an example, but the present application is not limited thereto. In the field of view structure, ambient light is used as the light source, and the target object directly reflects the ambient light to the scan head mirror.

[0074] ​Further, in the first embodiment, the angle of the field center line Ll of the projection lens 5 and the field center line L2 of the camera lens 9 is the parallax angle θ, and the field center line Ll of the projection lens 5 is offset from the optical axis OA1. However, the present application is not limited thereto, and the projection lens 5 of the first embodiment can be replaced with the projection lens 5 of the second embodiment, and the field center line Ll of the projection lens 5 can be set to coincide with the optical axis OA1, and the angle of the field center line Ll of the projection lens 5 and the field center line L2 of the camera lens 9 can be set to the parallax angle θ.

[0075] Further, in the second embodiment, the field center line Ll of the projection lens 5 coincides with the optical axis OA1, the angle of the field center line Ll of the projection lens 5 and the field center line L21 of the first camera lens 91 is the parallax angle θ, and the angle of the field center line Ll of the projection lens 5 and the field center line L22 of the second camera lens 92 is the parallax angle θ. However, the present application is not limited thereto, and the projection lens 5 of the second embodiment can be replaced with the projection lens 5 of the first embodiment, and the field center line Ll of the projection lens 5 can be set to be offset from the optical axis OA1, the angle of the field center line Ll of the projection lens 5 and the field center line L21 of the first camera lens 91 can be set to the parallax angle θ, and the angle of the field center line Ll of the projection lens 5 and the field center line L22 of the second camera lens 92 can be set to the parallax angle θ.

Claims

1. An optical path system applied to an oral digital impression apparatus, the optical path system comprising an optical path emitting subsystem (ES), a scanning head mirror (7) and at least one image receiving and processing subsystem (RS), the optical path emitting subsystem comprising a projection lens (5) for projecting an optical path of a light source to the scanning head mirror, the scanning head mirror being arranged opposite to a window (M) of a scanning head housing (6) of the oral digital impression apparatus, reflecting the optical path projected by the projection lens to a target object (8), the image receiving and processing subsystem comprising: a camera lens (9) receiving an image of the target object reflected via the scanning head mirror; and an image sensor module (10) receiving and processing the image of the target object, characterized in that: an optical axis of the projection lens is OA1, a field of view center line of the projection lens is L1, an optical axis of the camera lens is OA2, a field of view center line of the camera lens is L2, the field of view center line of the camera lens of at least one of the image receiving and processing subsystems is offset from the optical axis of the camera lens, the field of view center line of the projection lens and the field of view center line of the camera lens form a parallax included angle, an included angle of the optical axis of the projection lens and the optical axis of the camera lens is set to 0°≤ the included angle of the optical axis of the projection lens and the optical axis of the camera lens ≤ the parallax included angle, the field of view center line of the projection lens is offset from the optical axis of the projection lens, the field of view center line of the projection lens and the field of view center line of the camera lens form a parallax included angle; wherein: as the light source, the optical path emitting subsystem comprises an illumination module (1) generating an optical path, the optical path emitting subsystem further comprises: an optical path adjusting element emitting the optical path generated by the illumination module to the light modulation module at a required incident angle; and a light modulation module (4) for receiving the incident optical path and reflecting it at a certain angle, the projection lens is used for projecting the optical path reflected by the light modulation module to the scanning head mirror.

2. An optical path system applied to an oral digital impression apparatus, the optical path system comprising an optical path emitting subsystem (ES), a scanning head mirror (7) and at least one image receiving and processing subsystem (RS), the optical path emitting subsystem comprising a projection lens (5) for projecting an optical path of a light source to the scanning head mirror, the scanning head mirror being arranged opposite to a window (M) of a scanning head housing (6) of the oral digital impression apparatus, reflecting the optical path projected by the projection lens to a target object (8), the image receiving and processing subsystem comprising: a camera lens (9) receiving an image of the target object reflected via the scanning head mirror; and an image sensor module (10) receiving and processing the image of the target object, characterized in that: an optical axis of the projection lens is OA1, a field of view center line of the projection lens is L1, an optical axis of the camera lens is OA2, a field of view center line of the camera lens is L2, ​ ​ a field of view center line of the camera lens of at least one of the image receiving and processing subsystems is offset from an optical axis of the camera lens, a field of view center line of the projection lens forms a parallax included angle with a field of view center line of the camera lens, an included angle between an optical axis of the projection lens and an optical axis of the camera lens is set to 0°≤ the included angle between the optical axis of the projection lens and the optical axis of the camera lens ≤ the parallax included angle, a field of view center line of the projection lens coincides with an optical axis of the projection lens, a field of view center line of the projection lens forms a parallax included angle with a field of view center line of the camera lens; wherein, as the light source, the light path emitting subsystem includes an illumination module (1) that generates a light path, the light path emitting subsystem further includes: a light path adjusting element that emits the light path generated by the illumination module to the light modulation module at an incident angle required by the light modulation module; and a light modulation module (4) that is used to receive the incident light path and reflect it out at a certain angle, the projection lens is used to project the light path reflected by the light modulation module to the scanning head mirror.

3. The light path system according to claim 1 or 2, characterized in that, as the image receiving and processing subsystem, the light path system includes a first image receiving and processing subsystem (RS1) and a second image receiving and processing subsystem (RS2), the first image receiving and processing subsystem includes a first camera lens (91) and a first image sensor module (101), the second image receiving and processing subsystem includes a second camera lens (92) and a second image sensor module (102), an optical axis of the first camera lens is OA21, and a field of view center line is L21, an optical axis of the second camera lens is OA22, and a field of view center line is L22, the field of view center line of the first camera lens is offset from the optical axis of the first camera lens, the field of view center line of the second camera lens is offset from the optical axis of the second camera lens, an included angle between the field of view center line of the projection lens and the field of view center line of the first camera lens forms a parallax included angle, an included angle between the field of view center line of the projection lens and the field of view center line of the second camera lens forms a parallax included angle.

4. The light path system according to claim 1 or 2, characterized in that, the parallax included angle is set to a range of 6° to 10°.

5. The light path system according to claim 1 or 2, characterized in that, the light path adjusting element includes a first mirror (2) and a first lens (3), the first mirror emits the light path generated by the illumination module to the light modulation module via the first lens at an incident angle required by the light modulation module, the first lens reflects the light path modulated via the light modulation module to the projection lens at a certain angle.

6. The light path system according to claim 1 or 2, characterized in that, the scanning head mirror is arranged to be able to rotate within a specified angle range through an angle adjusting device.

7. An oral digital impression device, characterized in that, it includes the light path system according to any one of claims 1 to 6.

8. An intraoral digital impression device, comprising: it includes: The optical path system according to any one of claims 1 to 6; and An optical path system in which an optical axis of a projection lens and an optical axis of a camera lens form a parallax angle.

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