Illumination optics for 3D scanners and 3D scanners
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- J MORITA MANUFACTURING CORP
- Filing Date
- 2023-12-11
- Publication Date
- 2026-07-16
Smart Images
Figure 0007891458000003 
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Abstract
Description
Technical Field
[0001] The present disclosure relates to an illumination optical system for a three-dimensional scanner that acquires data on the three-dimensional surface shape of an object, and a three-dimensional scanner.
Background Art
[0002] In recent years, in the dental field, in order to digitally design prostheses and the like on a computer, it is necessary to acquire three-dimensional data on the surface shape of teeth, and three-dimensional scanners (intraoral scanners) have been put into practical use. For example, Patent Document 1 (Japanese Patent No. 5654583) discloses a three-dimensional scanner including a light source, a pattern generation means, a lens system including a lens that moves along the optical axis, and a camera. In this three-dimensional scanner, the lens is reciprocated along the optical axis to scan the light having the pattern that has passed through the pattern generation means and the lens, and the light having the pattern is irradiated onto the surface of the object, and the object is imaged by the camera. The image of the object captured by the camera is processed to obtain data on the three-dimensional surface shape of the object.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] When the object is a tooth, the material of the tooth surface is enamel. Since enamel is translucent, when a tooth is imaged with a three-dimensional scanner, the intensity of the light reflected or scattered by the tooth is weak. Therefore, it is necessary to increase the light amount of the light source. However, when the light amount of the light source increases, the power consumption and heat generation amount of the light source increase. The same problem exists not only when the object is a tooth but also when the reflected light or scattered light from the object is weak.
[0005] This disclosure is made to solve the above-mentioned problems, and its purpose is to provide an illumination optical system for a three-dimensional scanner and a three-dimensional scanner that can reduce the power consumption and heat generation of the light source, as well as be miniaturized. [Means for solving the problem]
[0006] The illumination optical system for a three-dimensional scanner described herein is for illuminating an object with light emitted from a light source, and comprises an illumination lens system and a reticle positioned on the object side relative to the illumination lens system. The illumination lens system consists of a first lens having positive power and a second lens having positive power, arranged in order from the light source side to the object side. The first lens is a biconvex lens. The light source side of the second lens is aspherical. The reticle includes a light-shielding pattern layer. The illumination optical system for a three-dimensional scanner satisfies the following conditions (1) and (2): 3.0 < |b / a| < 5.0 …(1) 0.03 < |c / d| < 0.09 …(2) however, a: Focal length of the first lens, b: Focal length of the second lens, c: Height of the light source's luminescent surface from the optical axis, d: Distance along the optical axis from the side of the light-shielding pattern layer to the light-emitting surface of the light source. That is the case.
[0007] The three-dimensional scanner of this disclosure comprises an illumination optical system for the three-dimensional scanner of this disclosure. [Effects of the Invention]
[0008] The illumination optical system for a three-dimensional scanner and the three-dimensional scanner of this disclosure can improve the utilization efficiency of light emitted from a light source. As a result, the power consumption and heat generation of the light source can be reduced. Furthermore, the illumination lens system in the illumination optical system for a three-dimensional scanner and the three-dimensional scanner of this disclosure consists of two lenses. As a result, the illumination optical system for a three-dimensional scanner and the three-dimensional scanner can be miniaturized. [Brief explanation of the drawing]
[0009] [Figure 1] This is a diagram showing a schematic view of a three-dimensional scanner according to an embodiment. [Figure 2] This is a developed view of an optical system according to an embodiment. [Figure 3] This is a diagram showing the optical configuration of an illumination optical system for a three-dimensional scanner according to Example 1. [Figure 4] This is a diagram showing the optical configuration of an illumination optical system for a three-dimensional scanner according to Example 2. [Figure 5] This is a diagram showing the optical configuration of an illumination optical system for a three-dimensional scanner according to a comparative example. [Figure 6] This is a diagram showing the aberrations (spherical aberration, astigmatism, and distortion) of Numerical Example 1. [Figure 7] This is a diagram showing the aberrations (spherical aberration, astigmatism, and distortion) of Numerical Example 2. [Figure 8] This is a diagram showing the aberrations (spherical aberration, astigmatism, and distortion) of a numerical comparative example. [Figure 9] This is a diagram showing the illuminance profile on the light source side surface of the light-shielding pattern layer of the reticle in Numerical Example 1. [Figure 10] This is a diagram showing the illuminance profile on the light source side surface of the light-shielding pattern layer of the reticle in Numerical Example 2. [Figure 11] This is a diagram showing the illuminance profile on the light source side surface of the light-shielding pattern layer of the reticle in a numerical comparative example. [Figure 12] This is a diagram showing the illuminance profile on the light-receiving surface of the optical sensor in Numerical Example 1. [Figure 13] This is a diagram showing the illuminance profile on the light-receiving surface of the optical sensor in Numerical Example 2. [Figure 14] This is a diagram showing the illuminance profile on the light-receiving surface of the optical sensor in a numerical comparative example.
Mode for Carrying Out the Invention
[0010] [Overview of Embodiment]
[0011] The overview of the embodiment of the present disclosure will be described by enumeration.
[0012] The illumination optical system for a three-dimensional scanner according to this embodiment is for irradiating an object with light emitted from a light source, and includes an illumination lens system and a reticle disposed on the object side with respect to the illumination lens system. The illumination lens system is composed of a first lens having a positive power and a second lens having a positive power in order from the light source side to the object side. The first lens is a biconvex lens. The light source side surface of the second lens is an aspherical surface. The reticle includes a light shielding pattern layer. The illumination optical system for a three-dimensional scanner according to this embodiment satisfies the following conditional expressions (1) and (2), 3.0 < |b / a| < 5.0 …(1) 0.03 < |c / d| < 0.09 …(2) However, a: Focal length of the first lens, b: Focal length of the second lens, c: Height of the light emitting surface of the light source from the optical axis, d: Distance on the optical axis from the light source side surface of the light shielding pattern layer to the light emitting surface of the light source, is.
[0013] Therefore, the utilization efficiency of the light emitted from the light source can be improved. As a result, the power consumption and the heat generation amount of the light source can be reduced. In addition, the illumination lens system is composed of two lenses. Therefore, the illumination optical system for a three-dimensional scanner can be miniaturized.
[0014] The illumination optical system for a three-dimensional scanner according to this embodiment satisfies the following conditional expression (3), 0.030 < |c / d| < 0.040 …(3) is.
[0015] Therefore, the efficiency of utilizing the light emitted from the light source can be improved. As a result, the power consumption and heat generation of the light source can be reduced. In addition, the illumination lens system consists of two lenses. Therefore, the illumination optical system for the 3D scanner can be miniaturized.
[0016] In the illumination optical system for the three-dimensional scanner of this embodiment, the first lens is made of glass.
[0017] The heat from the light source can prevent thermal deformation of the first lens. Since the object can be stably and brightly illuminated with light emitted from the light source, the measurement accuracy of the object's three-dimensional surface shape can be improved.
[0018] In the illumination optical system for the three-dimensional scanner of this embodiment, the first diameter of the first lens and the second diameter of the second lens are each 20 mm or less.
[0019] Therefore, the illumination optical system for the 3D scanner and the 3D scanner itself can be miniaturized.
[0020] The illumination optical system for the three-dimensional scanner of this embodiment satisfies the following condition (4): e ≤ 3.0 …(4) however, e: Distance along the optical axis between the light source side of the first lens and the light-emitting surface of the light source. (mm) That is the case.
[0021] Therefore, the efficiency of utilizing the light emitted from the light source can be improved. As a result, the power consumption and heat generation of the light source can be reduced. In addition, because the first lens is positioned close to the light source, the illumination optical system for the three-dimensional scanner can be miniaturized.
[0022] The three-dimensional scanner of this embodiment includes an illumination optical system for the three-dimensional scanner of this embodiment.
[0023] Therefore, the efficiency of utilizing the light emitted from the light source can be improved. As a result, the power consumption and heat generation of the light source can be reduced. In addition, the illumination lens system consists of two lenses. Therefore, the 3D scanner can be miniaturized.
[0024] [Details of the embodiment]
[0025] Based on the drawings, the details of the embodiments of this disclosure will be described below. In the drawings, identical or corresponding parts will be given the same reference numerals, and their descriptions will not be repeated. At least some of the configurations of the embodiments described below may be combined in any way.
[0026] Referring to Figure 1, the three-dimensional scanner 1 is a device that obtains data on the three-dimensional surface shape of an object 50. The three-dimensional scanner 1 is, for example, an intraoral scanner for obtaining data on the three-dimensional surface shape of oral tissue (e.g., teeth). However, even though it is an intraoral scanner, it may acquire data on the three-dimensional surface shape of not only teeth in the oral cavity, but also gums, mucous membranes, fabricated dental prostheses, implant scan bodies, orthodontic appliances, or various dental prosthetics. Furthermore, the three-dimensional scanner 1 of this embodiment is not limited to an intraoral scanner, but can be applied to other three-dimensional scanners, such as a three-dimensional scanner that images the inside of a person's ear to obtain data on the three-dimensional surface shape of the outer ear.
[0027] [Configuration of 3D scanner 1]
[0028] Referring to Figures 1 and 2, the three-dimensional scanner 1 comprises a handpiece 2 and a computer 45.
[0029] The handpiece 2 illuminates an object 50 (e.g., a tooth) with light having a pattern such as a line pattern or a checker pattern, and detects reflected or scattered light from the object 50. The handpiece 2 includes a housing 10, a light source 13, an illumination optical system 14 for the three-dimensional scanner, an objective optical system 3 for the three-dimensional scanner, and an optical sensor 39. The handpiece 2 may further include a moving mechanism 34, a lens position detector 35, and a controller 40.
[0030] The housing 10 houses a light source 13, an illumination optical system 14 for the three-dimensional scanner, an objective optical system 3 for the three-dimensional scanner, a moving mechanism 34, a lens position detector 35, an optical sensor 39, and a controller 40.
[0031] Referring to Figure 1, the light source 13 includes a light-emitting surface 13a. The light source 13 emits light (e.g., white light) from the light-emitting surface 13a to illuminate the object 50. The light source 13 is, for example, a light-emitting diode (LED). The output of the light source 13 is preferably 3W or more, and may be 4W or more. Therefore, even if the intensity of light reflected or scattered by the object 50 is weak, such as when the object 50 is a tooth, the object can be brightly illuminated with light emitted from the light source 13, thereby improving the measurement accuracy of the three-dimensional surface shape of the object 50.
[0032] Referring to Figure 1, the illumination optical system 14 for the three-dimensional scanner includes an illumination lens system 15 and a reticle 16. The illumination optical system 14 for the three-dimensional scanner may further include a polarizer 19.
[0033] The illumination lens system 15 makes the intensity distribution of light from the light source 13 more uniform. The illumination lens system 15 consists of lens L11 and lens L12, in order from the light source 13 side to the object side. Lens L11 and lens L12 correspond to the first lens and second lens of this disclosure, respectively. The configuration of the illumination lens system 15 will be described in detail later.
[0034] The reticle 16 is a pattern generating unit that generates patterned light (hereinafter also referred to as "pattern") by imparting an intensity pattern, such as a line pattern or a checkerboard pattern, to the light emitted from the light source 13. The reticle 16 generates patterned light that is irradiated onto the surface of the object 50. The reticle 16 includes a transparent plate 17 and a light-shielding pattern layer 18 disposed on the transparent plate 17. For example, the transparent plate 17 is a glass plate, and the light-shielding pattern layer 18 is a chromium layer. The light-shielding pattern layer 18 has a pattern such as a line pattern or a checkerboard pattern. The light-shielding pattern layer 18 is disposed, for example, on a first surface of the transparent plate 17 distal to the light source 13.
[0035] The polarizer 19 converts the light emitted from the light source 13 into linearly polarized light. The polarizer 19 is, for example, a polarizing film placed on the second surface of a transparent plate 17 that is close to the light source 13.
[0036] Referring to Figure 1, the objective optical system 3 for the three-dimensional scanner includes an objective lens system 30. The objective optical system 3 for the three-dimensional scanner may further include a beam splitter 20, a phase plate 37, and a mirror 38.
[0037] Referring to Figure 1, the beam splitter 20 is an optical component that separates the optical path from the light source 13 to the object 50 and the optical path from the object 50 to the optical sensor 39. The beam splitter 20 is positioned on the image plane side of the objective lens system 30. The beam splitter 20 is positioned between the objective lens system 30 and the illumination optical system 14 for the three-dimensional scanner, and also between the objective lens system 30 and the optical sensor 39. The beam splitter 20 directs the illumination light from the light source 13 to the object 50 and directs the reflected or scattered light from the object 50 to the optical sensor 39. The beam splitter 20 may also be a polarizing beam splitter 21.
[0038] Referring to Figure 1, the objective lens system 30 sends light with a pattern that has been emitted from the light source 13 and passed through the reticle 16 to the object 50, and also sends light reflected or scattered from the object 50 to the optical sensor 39. The objective lens system 30 consists of a first lens group G1 with positive power, a second lens group G2 with positive power, and a third lens group G3 with negative power, in order from the object side to the image plane side. When each lens is viewed with a paraxial plane shape, the first lens group G1 to the third lens group G3 are configured in order from the object side as follows.
[0039] The first lens group G1 consists of a negative meniscus lens L1 with its convex surface facing the object, a biconvex positive lens L2, a biconcave negative lens L3, and a biconvex positive lens L4. The positive lens L2 is an aspherical single lens. The negative lens L3 and the positive lens L4 are joined together to form a cemented lens with positive power. The aperture diaphragm ST is positioned on the image plane side of the positive lens L4.
[0040] The second lens group G2 consists of a biconvex positive lens L5. The positive lens L5 is an aspherical single lens.
[0041] The third lens group G3 consists of a negative meniscus lens L6 with its convex surface facing the image plane. The negative meniscus lens L6 is an aspherical single lens.
[0042] The lens L5 may be a movable lens that can move along the optical axis AX by a moving mechanism 34 described later. The objective lens system 30 may be a variable focal length lens system in which the focal length changes as the lens L5 moves along the optical axis. By changing the position of the lens L5 along the optical axis AX, the focal plane position of the light from the light source 13 (for example, light with a pattern) changes from the shortest focal position F1 closest to the output end face of the handpiece 2 (housing 10), through the intermediate focal position F2, to the longest focal position F3 furthest from the output end face of the handpiece 2 (housing 10). When the objective optical system 3 for the three-dimensional scanner changes from the shortest focal length state to the longest focal length state, the first lens group G1 and the third lens group G3 are fixed, and the second lens group G2 moves along the optical axis AX toward the image plane side (the light-receiving surface side of the optical sensor 39). Generally, there are object-side focal points and image-side focal points, but in this specification, the focal position described refers to the object-side focal point unless otherwise specified.
[0043] Referring to Figure 1, the phase plate 37 is positioned on the object side of the objective lens system 30. The phase plate 37 is, for example, a quarter-wave plate. The phase plate 37 converts the first linearly polarized light passing through the objective lens system 30 into circularly polarized light. The phase plate 37 converts the circularly polarized light reflected or scattered by the object 50 into second linearly polarized light having polarization perpendicular to the first linearly polarized light.
[0044] Referring to Figure 1, the mirror 38 is positioned on the object side of the objective lens system 30. More specifically, the mirror 38 is positioned on the object side of the phase plate 37. The mirror 38 reflects the light emitted from the light source 13 and passing through the objective lens system 30 toward the object 50. The mirror 38 also reflects the light reflected or scattered from the object 50 toward the objective lens system 30. The objective optical system 3 for the three-dimensional scanner is a projection optical system that projects light from the light source 13 onto the object 50, and an imaging optical system that transmits reflected or scattered light from the object 50 to the optical sensor 39.
[0045] Referring to Figures 1 and 2, the moving mechanism 34 moves the lens L5 along the optical axis AX. The moving mechanism 34 is a linear guide including, for example, a slider (not shown), a ball screw (not shown), and a motor (not shown). The lens L5 is fixed to the slider. The slider is guided by the ball screw and is movable relative to the ball screw. The motor rotates the ball screw. As the ball screw rotates, the slider moves relative to the ball screw, and the lens L5 moves along the optical axis AX.
[0046] Referring to Figures 1 and 2, the lens position detector 35 detects the position of lens L5 corresponding to the focal plane position of light (e.g., patterned light) from light source 13. The lens position detector 35 is, for example, an optical encoder that detects the position of lens L5.
[0047] Referring to Figures 1 and 2, the optical sensor 39 detects light that has been reflected or scattered by the object 50 and passed through the objective optical system 3 for the three-dimensional scanner. The optical sensor 39 is an image sensor, such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor, which images the object 50 and acquires an image of the object 50.
[0048] Referring to Figure 2, the controller 40 transmits a drive signal to the light source 13 to control the light emission state of the light source 13. The controller 40 transmits a drive signal to the moving mechanism 34 to move the lens L5. The controller 40 receives a signal from the lens position detector 35 regarding the position of the lens L5 corresponding to the focal plane position of the light from the light source 13 (e.g., light with a pattern).
[0049] The controller 40 processes the image of the object 50 acquired by the optical sensor 39 to calculate the three-dimensional surface shape data of the object 50. Specifically, the controller 40 calculates the three-dimensional surface shape data of the object 50 from the position of the lens L5 corresponding to the focal plane position of the light from the light source 13 (for example, light with a pattern) and the image acquired by the optical sensor 39 at each focal plane position.
[0050] Light with a pattern, emitted from the light source 13 and passed through the reticle 16, is irradiated onto the object 50 through the objective optical system 3 for the three-dimensional scanner. As the lens L5 moves along the optical axis AX, the focal plane position of the patterned light changes. The optical sensor 39 detects the light reflected or scattered from the object 50 at each focal plane position. The optical sensor 39 acquires a two-dimensional image of the object 50 at each focal plane position. The controller 40 associates the two-dimensional image of the object 50 with the position of the lens L5 corresponding to the focal plane position of the patterned light, and stores the combination of the two-dimensional image of the object 50 and the position of the lens L5 in memory (not shown). The controller 40 reads the combination from memory and stacks the two-dimensional images of the object 50 according to the focal plane position corresponding to each of the two-dimensional images. The X and Y coordinate positions of the object 50 are calculated from the two-dimensional image at the focal plane position. The Z coordinate position of the object 50 is calculated from the position of the lens L5. In this way, the controller 40 calculates data on the three-dimensional surface shape of the object 50.
[0051] The controller 40 can output data of the three-dimensional surface shape of the object 50 to the computer 45. The controller 40 can receive information such as settings and commands from the computer 45. The controller 40 includes a processor (e.g., a CPU (Central Processing Unit) or MPU (Micro Processing Unit)), a ROM (Read Only Memory) that stores programs and data for the processor to operate, a RAM (Random Access Memory) that functions as the processor's work area, and an input / output interface that handles the input and output of signals to and from peripheral devices. The program executed by the controller 40 may be provided by being permanently recorded on a tangible recording medium such as a CD-ROM, DVD-ROM, or semiconductor memory, or it may be provided via a communication network as a data signal superimposed on a carrier wave.
[0052] At least part of the calculation process for processing the image of the object 50 captured by the optical sensor 39 to obtain data of the three-dimensional surface shape of the object 50 may be performed by software or implemented by dedicated hardware separate from the processor. Furthermore, the processor or at least part of the hardware may be incorporated inside the handpiece 2. Although Figure 2 shows a cable for connecting the handpiece 2 to the computer 45 for communication, the handpiece 2 may also be connected to the computer 45 for communication via wireless communication without a cable.
[0053] The data of the three-dimensional surface shape of the object 50 obtained by the controller 40 is transmitted to the computer 45. The computer 45 performs rendering processing on the data of the three-dimensional surface shape of the object 50 to the display unit to generate a two-dimensional image of the object 50 as seen from an arbitrary viewpoint and displays it. The display unit may be a display built into the computer 45, a stationary display connected to the computer 45, or a wearable display (for example, a head-mounted display or glasses-type display) that is communicatively connected to the computer 45.
[0054] In this embodiment, the controller 40 processes the image captured by the optical sensor 39 to obtain data on the three-dimensional surface shape of the object 50. However, the computer 45 may also process the image captured by the optical sensor 39 to obtain data on the three-dimensional surface shape of the object 50.
[0055] The three-dimensional scanner 1 may further include a power supply unit (not shown) that supplies power to drive the light source 13, the moving mechanism 34, the lens position detector 35, the optical sensor 39, and the controller 40.
[0056] The operation of the three-dimensional scanner 1 will be explained using the example of using the three-dimensional scanner 1 of this embodiment as an intraoral scanner.
[0057] The tip of the handpiece 2 is inserted into the oral cavity. The controller 40 transmits a drive signal to the light source 13, causing the light source 13 to emit light. The light emitted from the light source 13 passes through the illumination lens system 15 to make the light intensity distribution more uniform. The light is converted into linearly polarized light by passing through the polarizer 19. The light is converted into patterned light by passing through the reticle 16. The patterned light passes through the polarizing beam splitter 21, the objective optical system 3 for the three-dimensional scanner, and the phase plate 37, is reflected by the mirror 38, and irradiates the object 50 (e.g., teeth). The controller 40 transmits a drive signal to the movement mechanism 34, causing the lens L5 to move back and forth along the optical axis AX. The movement of the lens L5 changes the focal plane position of the patterned light. The controller 40 receives a signal from the lens position detector 35 regarding the position of the lens L5 corresponding to the focal plane position of the light from the light source 13 (e.g., patterned light).
[0058] Light reflected or scattered from the object 50 is reflected by the mirror 38, passes through the phase plate 37 and the objective optical system 3 for the three-dimensional scanner, is reflected by the polarizing beam splitter 21, and enters the optical sensor 39. The optical sensor 39 detects the light reflected or scattered from the object 50 at each focal plane position. The optical sensor 39 acquires a two-dimensional image of the object 50 at each focal plane position. The controller 40 associates the two-dimensional image of the object 50 with the position of the lens L5 corresponding to the focal plane position of the patterned light, and stores the combination of the two-dimensional image of the object 50 and the position of the lens L5 in memory (not shown). The controller 40 reads the combination from memory and stacks the two-dimensional images of the object 50 according to the focal plane position corresponding to each of the two-dimensional images. In this way, the controller 40 calculates the data of the three-dimensional surface shape of the object 50.
[0059] [Configuration of illumination optical system 14 for 3D scanner]
[0060] Figures 3 and 4 show the configurations of the illumination optical system 14 for a three-dimensional scanner according to Example 1 and Example 2, respectively. Figure 5 shows the configuration of the illumination optical system 14b for a three-dimensional scanner according to the comparative example. As shown in Figure 1, the illumination optical system 14 for a three-dimensional scanner according to Example 1 and Example 2, and the illumination optical system 14b for a three-dimensional scanner according to the comparative example, each include an illumination lens system 15 and a reticle 16. The illumination optical system 14 for a three-dimensional scanner according to Example 1 and Example 2, and the illumination optical system 14b for a three-dimensional scanner according to the comparative example, may further include a polarizer 19.
[0061] (Example 1)
[0062] Referring to Figure 3, the illumination lens system 15 of the illumination optical system 14 for a three-dimensional scanner according to Embodiment 1 consists of a positive power lens L11 and a positive power lens L12, in order from the light source side to the object side. When viewing each lens in terms of its paraxial plane shape, the lenses L11 and L12 of Embodiment 1 are configured as follows, in order from the object side.
[0063] Lens L11 is a biconvex lens. Lens L11 is made of glass. The diameter of lens L11 is 20 mm or less.
[0064] Lens L12 is an aspherical lens. The light source side of lens L12 is aspherical. The object side of lens L12 may also be aspherical. Lens L12 is a biconvex lens overall, but in the paraxial region, it is a negative meniscus lens with the convex side facing the object. Lens L12 may be made of plastic or glass. The diameter of lens L12 is 20 mm or less.
[0065] (Example 2)
[0066] Referring to Figure 4, the illumination lens system 15 of the illumination optical system 14 for a three-dimensional scanner according to Embodiment 2 consists of a positive power lens L11 and a positive power lens L12, in order from the light source side to the object side. When viewing each lens in terms of its paraxial plane shape, the lenses L11 and L12 of Embodiment 2 are configured as follows, in order from the object side.
[0067] Lens L11 is a biconvex lens. Lens L11 is made of glass. The diameter of lens L11 is 20 mm or less.
[0068] Lens L12 is an aspherical lens. The light source side of lens L12 is aspherical. The object side of lens L12 may also be aspherical. Lens L12 is a biconvex lens overall, but in the paraxial region, it is a negative meniscus lens with the convex side facing the object. Lens L12 may be made of plastic or glass. The diameter of lens L12 is 20 mm or less.
[0069] (Comparative example)
[0070] Referring to Figure 5, the illumination lens system 15 of the illumination optical system 14b for a three-dimensional scanner in the comparative example consists of a positive power lens L11 and a positive power lens L12, in order from the light source side to the object side. When viewing each lens in terms of its paraxial plane shape, the lenses L11 and L12 of the comparative example are configured as follows, in order from the object side.
[0071] Lens L11 is a biconvex lens. Lens L11 is an aspherical lens. Specifically, the object side of lens L11 (the side opposite the light source side) is aspherical. The light source side of lens L11 is spherical. Lens L11 is made of glass. The diameter of lens L11 is 20 mm or less.
[0072] Lens L12 is a biconvex lens. Specifically, lens L12 is a biconvex lens both overall and in the paraxial region. Lens L12 is an aspherical lens. Specifically, the object side of lens L12 (the side opposite the light source side) is aspherical. The light source side of lens L12 is spherical. Lens L12 may be made of plastic or glass. The diameter of lens L12 is 20 mm or less.
[0073] (Examples of numerical examples, comparative examples of numerical examples)
[0074] The optical configuration of the illumination optical system 14 for a three-dimensional scanner according to the embodiment will be described in detail below, with reference to construction data, etc., while comparing it with the optical configuration of the illumination optical system 14b for a three-dimensional scanner according to the comparative example. Numerical embodiment 1 and numerical embodiment 2 are numerical embodiments corresponding to the above-mentioned embodiment 1 and embodiment 2, respectively. Numerical comparative example is a numerical embodiment corresponding to the above-mentioned comparative example.
[0075] In Numerical Example 1, Numerical Example 2, and Numerical Comparative Example, the surface data, from left to right, shows the surface number, radius of curvature r (mm), on-axis surface spacing d (mm), refractive index nd with respect to the d line (wavelength 587.56 nm), and Abbe number νd with respect to the d line. Surface number 1 represents the light source side of the light-shielding pattern layer 18 of the reticle 16, that is, the object side of the transparent plate 17 on which the light-shielding pattern layer 18 of the reticle 16 is formed (the side of the transparent plate 17 opposite to the light source side). Surface number 2 represents the object side of the polarizer 19 (that is, the light source side of the transparent plate 17). Surface number 3 represents the light source side of the polarizer 19. Surface number 8 represents the light-emitting surface 13a of the light source 13. Surfaces marked with an asterisk (*) in surface number i are aspherical surfaces, and their surface shape is defined by the following equation (AS) using a local Cartesian coordinate system (x,y,z) with the surface vertex as the origin. Aspherical data such as aspherical coefficients are shown. Note that in the aspherical data of Numerical Examples 1 to 3 and the Numerical Comparative Example, the coefficients of terms that are not expressed are 0, and for all data, en = ×10 -n That is the case. z=(c·h 2 ) / [1+√{1-(1+K)·c 2 ·h2}]+Σ(Aj·hj) …(AS) however, h: Height in the direction perpendicular to the z axis (optical axis AX) (h 2 =x 2 +y 2 ), z: Sag amount in the optical axis AX direction at height h (relative to the surface vertex), c: Curvature at the face vertex (reciprocal of the radius of curvature r), K: cone constant, Aj: j-th order aspherical coefficient, That is the case.
[0076] The following data points are shown for the entire system: focal length (Fl, mm), F-number (Fno.), half-angle of view (ω, °), image height (y'max, mm), total lens length (TL, mm), and back focus (BF, mm). The F-number is defined as the angle at which lens L11 captures the light rays emitted from light source 13. The half-angle of view is defined as the angle of the light rays illuminating the side of the light source on the light-shielding pattern layer 18. The total lens length TL is the distance from the side of the light source on the light-shielding pattern layer 18 to the light-emitting surface 13a of light source 13. The back focus BF is expressed as the air-equivalent length of the distance from the side of lens L11 on the light source to the light-emitting surface 13a of light source 13.
[0077] The spherical aberration diagrams in Figures 6 to 8 show the amount of spherical aberration for the d line (wavelength 587.56 nm) (shown as a solid line), the amount of spherical aberration for the C line (wavelength 656.28 nm) (shown as a dashed line), and the amount of spherical aberration for the g line (wavelength 435.84 nm) (shown as a dashed line), each expressed as the amount of focal position deviation (unit: mm) in the optical axis AX direction from the paraxial image plane. The vertical axis represents the value normalized by the maximum height of incidence to the pupil (i.e., relative pupil height).
[0078] In the astigmatism diagrams from Figures 6 to 8, the dashed line T represents the tangential image plane relative to the d line, expressed as the amount of deviation (in mm) of the focal position in the optical axis AX direction from the paraxial image plane, and the solid line S represents the sagittal image plane relative to the d line, expressed as the amount of deviation (in mm) of the focal position in the optical axis AX direction from the paraxial image plane. The vertical axis represents the value of the ray height at the image plane normalized by its maximum image height (i.e., relative image height).
[0079] In the distortion diagrams from Figures 6 to 8, the horizontal axis represents the distortion with respect to the d line as a ratio (in %) of the actual image height to the ideal image height, and the vertical axis represents the value of the ray height at the image plane normalized by its maximum image height (i.e., relative image height).
[0080] Numerical Example 1 Unit: mm Surface data Face number rd nd vd 1 infinity 2.300 1.4585 67.82 2 infinity 0.210 1.4918 57.44 3 infinity 0.790 4* 12.55 4.500 1.535 55.71 5* 702.38 5.800 6 7.29 7.000 1.8707 40.73 7 -18.67 1.000 8 infinity Aspherical data Surface number K A4 A6 A8 4 1 4.7412618E-05 -1.1451091E-06 -4.0969509E-08 5 0 -2.8087710E-04 7.2040151E-07 4.0313578E-08 Various data Fl 7.88 Fno. 0.59 ω 7.50 y'max 0.70 TL 21.600 BF 1.00
[0081] Numerical Example 2 Unit: mm Surface data Face number rd nd vd 1 infinity 2.300 1.4585 67.82 2 infinity 0.210 1.4918 57.44 3 infinity 0.790 4* 12.28 4.500 1.5350 55.71 5* 144.00 4.801 6 7.10 8.000 1.8830 40.81 7 -12.00 0.500 8 infinity Aspherical data Surface number K A4 A6 A8 4 1 6.7224990E-05 -1.0794507E-06 -3.4379434E-08 5 0 -3.1347788E-04 7.2013248E-07 2.6173953E-08 Various data Fl 7.34 Fno. 0.59 ω 7.50 y'max 0.70 TL 21.101 BF 0.50
[0082] Numerical Comparison Example Unit: mm Surface data Face number rd nd vd 1 infinity 2.300 1.4585 67.82 2 infinity 0.210 1.4918 57.44 3 infinity 0.707 4* 14.45 3.440 1.535 55.71 5 -60.21 6.220 6* 6.95 8.340 1.535 55.71 7 -7.04 1.005 8 infinity Aspherical data Surface number K A4 A6 A8 4 1.0520651E-02 -1.0710467E-04 3.9841502E-07 1.0233607E-12 6 2.9765896E-01 2.0050235E-05 -1.8744481E-07 -7.4330378E-09 Various data Fl 9.66 Fno. 0.67 ω 7.50 y'max 1.00 TL 22.222 BF 1.00
[0083] Table 1 shows the numerical values for Numerical Example 1, Numerical Example 3, and Numerical Comparative Example. Table 2 shows the corresponding values for the conditional expressions for Numerical Example 1, Numerical Example 3, and Numerical Comparative Example. [Table 1] [Table 2]
[0084] Figures 9 to 11 show the illuminance profiles of the light-shielding pattern layer 18 of the reticle 16 on the light source side for Numerical Example 1, Numerical Example, and Numerical Comparison Example. In Figures 9 to 11, the horizontal axis represents the position (real image height) of the light-shielding pattern layer 18 on the light source side from the optical axis, and the vertical axis represents the light intensity at that position. Figures 12 to 14 show the illuminance profiles on the light-receiving surface of the optical sensor for Numerical Example 1, Numerical Example, and Numerical Comparison Example. In the illuminance profiles of Figures 12 to 14, the horizontal axis represents the position (real image height) of the optical sensor 39 on the light-receiving surface from the optical axis, and the vertical axis represents the light intensity at that position.
[0085] From Figures 9 to 11, it can be seen that in numerical example 1 and numerical example 2, the area between the illuminance profile and the horizontal axis is larger than in the numerical comparison example, the peak value of the illuminance profile is larger, and the illuminance profile rises more steeply. Similarly, from Figures 12 to 14, it can be seen that in numerical example 1 and numerical example 2, the area between the illuminance profile and the horizontal axis is larger than in the numerical comparison example, the peak value of the illuminance profile is larger, and the illuminance profile rises more steeply. Therefore, in numerical example 1 and numerical example 2, the amount of light on the light-shielding pattern layer 18 of the reticle 16 is increased compared to the numerical comparison example, and as a result, the amount of light on the light-receiving surface of the optical sensor is increased in numerical example 1 and numerical example 2 compared to the numerical comparison example. In numerical example 1 and numerical example 2, the utilization efficiency of the light emitted from the light source is improved compared to the numerical comparison example.
[0086] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended. [Explanation of Symbols]
[0087] 1 3D scanner, 2 handpiece, 3,3b objective optical system for 3D scanner, 10 housing, 13 light source, 13a light-emitting surface, 14 illumination optical system for 3D scanner, 15 illumination lens system, 16 reticle, 17 transparent plate, 18 light-shielding pattern layer, 19 polarizer, 20 beam splitter, 21 polarizing beam splitter, 30 objective lens system, 34 movement mechanism, 35 lens position detector, 37 phase plate, 38 mirror, 39 optical sensor, 40 controller, 45 computer, 50 object, AX optical axis, G1 first lens group, G2 second lens group, G3 third lens group, L1, L2, L3, L4, L5, L6, L11, L12 lenses.
Claims
1. An illumination optical system for a three-dimensional scanner, for irradiating an object with light emitted from a light source, Illumination lens system, The system comprises a reticle positioned on the object side relative to the illumination lens system, The aforementioned illumination lens system Starting from the light source and moving towards the object, A first lens with positive power, It consists of a second lens with positive power, The first lens is a biconvex lens, The light source side of the second lens is aspherical, The reticle includes a light-shielding pattern layer, An illumination optical system for a three-dimensional scanner that satisfies the following conditions (1) and (2): 3.0<|b / a|<5.0...(1) 0.03<|c / d|<0.09...(2) however, a: Focal length of the first lens, b: Focal length of the second lens, c: Height of the light-emitting surface of the light source from the optical axis, d: Distance along the optical axis from the light-shielding pattern layer to the light-emitting surface of the light source, That is the case.
2. An illumination optical system for a three-dimensional scanner according to claim 1, satisfying the following condition (3). 0.030<|c / d|<0.040...(3)
3. The illumination optical system for a three-dimensional scanner according to claim 1, wherein the first lens is made of glass.
4. The illumination optical system for a three-dimensional scanner according to claim 1, wherein the first diameter of the first lens and the second diameter of the second lens are each 20 mm or less.
5. An illumination optical system for a three-dimensional scanner according to claim 1, satisfying the following condition (4): e ≤ 3.0 …(4) however, e: Distance (mm) along the optical axis between the side surface of the light source of the first lens and the light-emitting surface of the light source. That is the case.
6. A three-dimensional scanner comprising the illumination optical system for a three-dimensional scanner according to any one of claims 1 to 5.