Illumination optical system for three-dimensional scanners and three-dimensional scanner

Abstract

To provide an illumination optical system for three-dimensional scanners with which it is possible to improve the utilization efficiency of light radiated from a light source, and which is built in a compact size.SOLUTION: An illumination optical system 14 for three-dimensional scanners comprises an illumination lens system 15 and a reticle 16. The illumination lens system 15 is composed of a lens L11 having positive power and a lens L12 having positive power, in order from the light source side to the object side. The lens L11 is a biconvex lens. The light source-side surface of the lens L12 is aspherical. The reticle 16 includes a shading pattern layer 18. The illumination optical system 14 for three-dimensional scanners satisfies the conditional expression 3.0<|b / a|<5.0 and the conditional expression 0.03<|c / d|<0.09.SELECTED DRAWING: Figure 1

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 an 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] The present disclosure has been made to solve the above problems, and an object thereof 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 amount of a light source and can be miniaturized.

Means for Solving the Problems

[0006] The illumination optical system for a three-dimensional scanner of the present disclosure is for irradiating an object with light radiated 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 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.

[0007] The three-dimensional scanner of the present disclosure includes the illumination optical system for a three-dimensional scanner of the present disclosure.

Effects of the Invention

[0008] According to the illumination optical system for a three-dimensional scanner of the present disclosure and the three-dimensional scanner of the present disclosure, the utilization efficiency of the light radiated from the light source can be improved. Therefore, the power consumption and heat generation amount of the light source can be reduced. Further, in the illumination optical system for a three-dimensional scanner and the three-dimensional scanner of the present disclosure, the illumination lens system is composed of two lenses. Therefore, the illumination optical system for a three-dimensional scanner and the three-dimensional scanner can be miniaturized.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0010] [Overview of Embodiment]

[0011] The overview of the embodiment of the present disclosure will be described by way of 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 amount of heat generation 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 utilization efficiency of the light emitted from the light source can be improved. As a result, the power consumption and the amount of heat generation of the light source can be reduced. Further, the illumination lens system is composed of two lenses. Therefore, the illumination optical system for the three-dimensional scanner can be miniaturized.

[0016] In the illumination optical system for the three-dimensional scanner according to the present embodiment, the first lens is made of glass.

[0017] Thermal deformation of the first lens can be prevented by the heat of the light source. Since the object can be stably and brightly illuminated with the light emitted from the light source, the measurement accuracy of the three-dimensional surface shape of the object can be improved.

[0018] In the illumination optical system for the three-dimensional scanner according to the present 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 three-dimensional scanner and the three-dimensional scanner can be miniaturized.

[0020] The illumination optical system for the three-dimensional scanner according to the present embodiment satisfies the following conditional expression (4), e ≦ 3.0 …(4) However, e: The distance on the optical axis between the side surface of the light source of the first lens and the light emitting surface of the light source is.

[0021] Therefore, the utilization efficiency of the light emitted from the light source can be improved. As a result, the power consumption and the amount of heat generation of the light source can be reduced. Further, since the first lens is arranged closer to the light source, the illumination optical system for the three-dimensional scanner can be miniaturized.

[0022] The three-dimensional scanner according to the present embodiment includes the illumination optical system for the three-dimensional scanner according to the present embodiment.

[0023] Therefore, the utilization efficiency of the light emitted from the light source can be improved. As a result, the power consumption and the amount of heat generation of the light source can be reduced. Further, the illumination lens system is composed of two lenses. Therefore, the three-dimensional scanner can be miniaturized.

[0024] [Details of Embodiment]

[0025] Based on the drawings, the details of the embodiments of the present disclosure will be described below. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated. At least some of the configurations of the embodiments described below may be arbitrarily combined.

[0026] Referring to FIG. 1, the three-dimensional scanner 1 is a device that obtains data on the three-dimensional surface shape of the object 50. The three-dimensional scanner 1 is, for example, an intraoral scanner for obtaining data on the three-dimensional surface shape of intraoral tissues (for example, teeth). Note that even in the case of an intraoral scanner, not only the teeth in the oral cavity but also the three-dimensional surface shape data of the gingiva, mucosa, fabricated dental prosthesis, scan body for implant, orthodontic device, or various dental laboratory products may be acquired. Further, the three-dimensional scanner 1 of the present embodiment is not limited to an intraoral scanner, and 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 inside the outer ear.

[0027] [Configuration of Three-Dimensional Scanner 1]

[0028] Referring to FIGS. 1 and 2, the three-dimensional scanner 1 includes a handpiece 2 and a computer 45.

[0029] The handpiece 2 irradiates an object 50 (e.g., a tooth) with light having a pattern such as a line pattern or a checker pattern, and detects reflected light or scattered light from the object 50. The handpiece 2 includes a housing 10, a light source 13, a three-dimensional scanner illumination optical system 14, a three-dimensional scanner objective optical system 3, and an optical sensor 39. The handpiece 2 may further include a movement mechanism 34, a lens position detector 35, and a controller 40.

[0030] The housing 10 houses the light source 13, the three-dimensional scanner illumination optical system 14, the three-dimensional scanner objective optical system 3, the movement mechanism 34, the lens position detector 35, the optical sensor 39, and the controller 40.

[0031] Referring to FIG. 1, the light source 13 includes a light emitting surface 13a. The light source 13 emits light (e.g., white light) for illuminating the object 50 from the light emitting surface 13a. The light source 13 is, for example, a light emitting diode (LED). The output of the light source 13 is preferably 3 W or more, and may be 4 W or more. Therefore, even when the intensity of the light reflected or scattered by the object 50 is weak as in the case where the object 50 is a tooth, the object can be brightly illuminated with the light emitted from the light source 13, so that the measurement accuracy of the three-dimensional surface shape of the object 50 can be improved.

[0032] Referring to FIG. 1, the three-dimensional scanner illumination optical system 14 includes an illumination lens system 15 and a reticle 16. The three-dimensional scanner illumination optical system 14 may further include a polarizer 19.

[0033] The illumination lens system 15 makes the intensity distribution of the light from the light source 13 more uniform. The illumination lens system 15 is composed of a lens L11 and a lens L12 in order from the light source 13 side to the object side. The lens L11 and the lens L12 respectively correspond to the first lens and the second lens of the present disclosure. The configuration of the illumination lens system 15 will be described in detail later.

[0034] The reticle 16 is a pattern generation unit that gives an intensity pattern such as a line pattern or a checker pattern to the light emitted from the light source 13 to generate light with a pattern (hereinafter also referred to as "pattern"). The reticle 16 generates light with a pattern 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 checker pattern. The light-shielding pattern layer 18 is disposed, for example, on the first surface of the transparent plate 17 distal from 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 disposed on the second surface of the transparent plate 17 proximal to the light source 13.

[0036] Referring to FIG. 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 FIG. 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 disposed on the image plane side of the objective lens system 30. The beam splitter 20 is disposed between the objective lens system 30 and the illumination optical system 14 for the three-dimensional scanner, and is also disposed between the objective lens system 30 and the optical sensor 39. The beam splitter 20 directs the illumination light from the light source 13 toward the object 50, and directs the reflected light or scattered light from the object 50 toward the optical sensor 39. The beam splitter 20 may be a polarizing beam splitter 21.

[0038] Referring to FIG. 1, the objective lens system 30 sends the light having the pattern radiated from the light source 13 and passing through the reticle 16 to the object 50, and sends the light reflected or scattered from the object 50 to the optical sensor 39. The objective lens system 30 is composed of a first lens group G1 having a positive power, a second lens group G2 having a positive power, and a third lens group G3 having a negative power, in order from the object side to the image plane side. The first lens group G1 to the third lens group G3 are each configured as follows when each lens is viewed with a paraxial surface shape, in order from the object side.

[0039] The first lens group G1 is composed of a negative meniscus lens L1 with a convex surface facing the object side, 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 to each other to form a joined lens having a positive power. The aperture stop ST is disposed on the image plane side of the positive lens L4.

[0040] The second lens group G2 is composed of a biconvex positive lens L5. The positive lens L5 is an aspherical single lens.

[0041] The third lens group G3 is composed of a negative meniscus lens L6 with a convex surface facing the image plane side. 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 whose 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 having a pattern) changes from the shortest focal position F1 closest to the exit end face of the handpiece 2 (housing 10), through the intermediate focal position F2, to the longest focal position F3 farthest from the exit 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 side (the light receiving surface side of the optical sensor 39). Note that generally there are an object-side focus and an image-side focus, but the focal position described in this specification means the object-side focus unless otherwise specified.

[0043] Referring to FIG. 1, the phase plate 37 is disposed 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 a polarization orthogonal to the first linearly polarized light.

[0044] Referring to FIG. 1, the mirror 38 is disposed on the object side of the objective lens system 30. More specifically, the mirror 38 is disposed 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 reflects the light reflected or scattered by 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 the light from the light source 13 onto the object 50 and an imaging optical system that transmits the reflected light or scattered light from the object 50 to the optical sensor 39.

[0045] Referring to FIGS. 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. When 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 FIGS. 1 and 2, the lens position detector 35 detects the position of the lens L5 corresponding to the focal plane position of the light (for example, light having a pattern) from the light source 13. The lens position detector 35 is, for example, an optical encoder that detects the position of the lens L5.

[0047] Referring to FIGS. 1 and 2, the optical sensor 39 detects the light that has been reflected or scattered by the object 50 and has passed through the objective optical system 3 for the three-dimensional scanner. The optical sensor 39 is an image sensor that images the object 50 and acquires an image of the object 50, such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor, for example.

[0048] Referring to FIG. 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 regarding the position of the lens L5 corresponding to the focal plane position of the light (for example, light having a pattern) from the light source 13 from the lens position detector 35.

[0049] The controller 40 processes the image of the object 50 acquired by the optical sensor 39 to calculate the data of the three-dimensional surface shape of the object 50. Specifically, the controller 40 calculates the data of the three-dimensional surface shape 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 having a pattern) and the image acquired by the optical sensor 39 at each focal plane position.

[0050] The light having a pattern emitted from the light source 13 and obtained through the reticle 16 is irradiated onto the object 50 through the objective optical system 3 for the three-dimensional scanner. When the lens L5 moves along the optical axis AX, the focal plane position of the light having a pattern changes. The optical sensor 39 detects the light reflected or scattered from the object 50 at each focal plane position. By the optical sensor 39, a two-dimensional image of the object 50 at each focal plane position is acquired. 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 light having a pattern, and stores the combination of the two-dimensional image of the object 50 and the position of the lens L5 in a memory (not shown). The controller 40 reads out the combination from the 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 coordinate position and the Y coordinate position 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 the data of the three-dimensional surface shape of the object 50.

[0051] The controller 40 can output data on 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 an MPU (Micro Processing Unit), etc.), a ROM (Read Only Memory) that stores a program and data for the operation of the processor, a RAM (Random Access Memory) that functions as a work area of the processor, and an input / output interface that is responsible for input / output of signals with peripheral devices, etc. The program executed by the controller 40 may be provided after being fixedly recorded on a tangible recording medium such as a CD-ROM, a DVD-ROM, or a semiconductor memory, or may be provided via a communication network as a data signal superimposed on a carrier wave.

[0052] At least a part of the arithmetic processing for processing the image of the object 50 captured by the optical sensor 39 to obtain data on the three-dimensional surface shape of the object 50 may be executed by software or may be realized by dedicated hardware separate from the processor. Also, at least a part of the processor or the hardware may be incorporated inside the handpiece 2. Although a cable for communicably connecting the handpiece 2 to the computer 45 is depicted in FIG. 2, the handpiece 2 may be communicably connected to the computer 45 by wireless communication without providing the 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 on the display unit, generates a two-dimensional image of the object 50 viewed from an arbitrary viewpoint, and displays it. The display unit may be a display built into the computer 45, or a stationary display connected to the computer 45, or a wearable display (for example, a head-mounted display or a glasses-type display) communicably connected to the computer 45, etc.

[0054] In this embodiment, the controller 40 processes the image captured by the optical sensor 39 to obtain the data of 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 the data of the three-dimensional surface shape of the object 50.

[0055] The three-dimensional scanner 1 may further include a power supply device (not shown) for supplying power to drive the light source 13, the moving mechanism 34, the lens position detector 35, the optical sensor 39, the controller 40, etc.

[0056] Taking the case where the three-dimensional scanner 1 of this embodiment is used as an intraoral scanner as an example, the operation of the three-dimensional scanner 1 will be described.

[0057] Insert the tip of the handpiece 2 into the oral cavity. The controller 40 transmits a drive signal to the light source 13 to cause 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 intensity distribution of the light more uniform. The light passes through the polarizer 19 and is converted into linearly polarized light. The light passes through the reticle 16 and is converted into light having a pattern. The light having a pattern 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 (for example, a tooth). The controller 40 transmits a drive signal to the moving mechanism 34 to reciprocate the lens L5 along the optical axis AX. Due to the movement of the lens L5, the focal plane position of the light having a pattern changes. The controller 40 receives a signal regarding the position of the lens L5 corresponding to the focal plane position of the light from the light source 13 (for example, the light having a pattern) from the lens position detector 35.

[0058] The 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. By the optical sensor 39, a two-dimensional image of the object 50 at each focal plane position is acquired. 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 light having a pattern, and stores the combination of the two-dimensional image of the object 50 and the position of the lens L5 in a memory (not shown). The controller 40 reads out the combination from the memory and stacks the two-dimensional images of the object 50 according to the focal plane positions corresponding to the respective two-dimensional images. Thus, the controller 40 calculates the data of the three-dimensional surface shape of the object 50.

[0059] [Configuration of the Illumination Optical System 14 for the Three-Dimensional Scanner]

[0060] Figures 3 and 4 respectively show the configurations of the illumination optical system 14 for the three-dimensional scanner according to Example 1 and Example 2. Figure 5 shows the configuration of the illumination optical system 14b for the three-dimensional scanner according to the comparative example. As shown in Figure 1, the illumination optical system 14 for the three-dimensional scanner according to Example 1 and Example 2 and the illumination optical system 14b for the 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 the three-dimensional scanner according to Example 1 and Example 2 and the illumination optical system 14b for the three-dimensional scanner according to the comparative example may each 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 the three-dimensional scanner according to Example 1 is composed of a lens L11 having a positive power and a lens L12 having a positive power in order from the light source side to the object side. The lens L11 and lens L12 of Example 1 are configured as follows when each lens is viewed with a paraxial surface shape, 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 surface of lens L12 is aspherical. The object side surface of lens L12 may be aspherical. Although lens L12 is a biconvex lens as a whole, in the paraxial region, it is a negative meniscus lens with the convex surface facing the object side. 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 FIG. 4, the illumination lens system 15 of the three-dimensional scanner illumination optical system 14 according to Embodiment 2 is composed of a lens L11 having a positive power and a lens L12 having a positive power in order from the light source side to the object side. The lens L11 and the lens L12 of Embodiment 2 are configured as follows in order from the object side when each lens is viewed with a paraxial surface shape.

[0067] The lens L11 is a biconvex lens. The lens L11 is made of glass. The diameter of the lens L11 is 20 mm or less.

[0068] The lens L12 is an aspherical lens. The light source side surface of the lens L12 is an aspherical surface. The object side surface of the lens L12 may be an aspherical surface. As a whole, the lens L12 is a biconvex lens, but in the paraxial region, it is a negative meniscus lens with the convex surface facing the object side. The lens L12 may be made of plastic or glass. The diameter of the lens L12 is 20 mm or less.

[0069] (Comparative Example)

[0070] Referring to FIG. 5, the illumination lens system 15 of the three-dimensional scanner illumination optical system 14b according to the comparative example is composed of a lens L11 having a positive power and a lens L12 having a positive power in order from the light source side to the object side. The lens L11 and the lens L12 of the comparative example are configured as follows in order from the object side when each lens is viewed with a paraxial surface shape.

[0071] The lens L11 is a biconvex lens. The lens L11 is an aspherical lens. Specifically, the object side surface (the surface opposite to the light source side surface) of the lens L11 is an aspherical surface. The light source side surface of the lens L11 is a spherical surface. The lens L11 is made of glass. The diameter of the lens L11 is 20 mm or less.

[0072] The lens L12 is a biconvex lens. Specifically, the lens L12 is a biconvex lens both as a whole and in the paraxial region. The lens L12 is an aspherical lens. Specifically, the object side surface (the surface opposite to the light source side surface) of the lens L12 is aspherical. The light source side surface of the lens L12 is spherical. The lens L12 may be made of plastic or glass. The diameter of the lens L12 is 20 mm or less.

[0073] (Numerical Examples, Numerical Comparative Examples)

[0074] Hereinafter, while contrasting with the optical configuration of the illumination optical system 14b for a three-dimensional scanner according to the comparative example, the optical configuration of the illumination optical system 14 for a three-dimensional scanner according to the example will be specifically described by citing construction data and the like. Numerical Example 1 and Numerical Example 2 are numerical examples corresponding to Example 1 and Example 2 described above, respectively. The numerical comparative example is a numerical example corresponding to the comparative example described above.

[0075] In Numerical Example 1, Numerical Example 2, and the numerical comparative example, as surface data, in order from the left column, the surface number, radius of curvature r (mm), axial surface interval 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 are shown. Surface number 1 represents the light source side surface of the light shielding pattern layer 18 of the reticle 16, that is, the object side surface (the surface opposite to the light source side surface of the transparent plate 17) of the transparent plate 17 on which the light shielding pattern layer 18 of the reticle 16 is formed. Surface number 2 represents the object side surface of the polarizer 19 (that is, the light source side surface of the transparent plate 17). Surface number 3 represents the light source side surface of the polarizer 19. Surface number 8 represents the light emitting surface 13a of the light source 13. The surface with an asterisk (*) attached to surface number i is aspherical, and its surface shape is defined by the following formula (AS) using a local orthogonal coordinate system (x, y, z) with the surface vertex as the origin. As aspherical data, aspherical coefficients and the like are shown. In addition, the coefficients of the terms not shown in the aspherical data of Numerical Example 1 to Numerical Example 3 and the numerical comparative example are 0, and for all data, e-n = ×10 -n is. z=(c·h 2 ) / [1+√{1-(1+K)·c 2 ·h2 [[ID=1}}]+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 direction of the optical axis AX at the position of height h (with respect to the surface vertex), c: curvature at the surface vertex (reciprocal of the radius of curvature r), K: conic constant, Aj: j-th aspheric coefficient, where.

[0076] As various data, the focal length (Fl, mm), F-number (Fno.), half field angle (ω, °), image height (y’max, mm), total lens length (TL, mm), and back focus (BF, mm) of the entire system are shown. The F-number is defined by the angle at which the lens L11 captures the light rays emitted from the light source 13. The half field angle is defined by the angle of the light rays illuminating the light source side surface of the light shielding pattern layer 18. The total lens length TL is the distance from the light source side surface of the light shielding pattern layer 18 to the light emitting surface 13a of the light source 13. The back focus BF represents the distance from the light source side surface of the lens L11 to the light emitting surface 13a of the light source 13 in terms of the air equivalent length.

[0077] The spherical aberration diagrams in FIGS. 6 to 8 show the spherical aberration amounts (indicated by solid lines) for the d-line (wavelength 587.56 nm), the spherical aberration amounts (indicated by dashed-dotted lines) for the C-line (wavelength 656.28 nm), and the spherical aberration amounts (indicated by dashed lines) for the g-line (wavelength 435.84 nm), respectively, as the deviation amounts (unit: mm) of the focal positions in the direction of the optical axis AX from the paraxial image plane. The vertical axis represents the value obtained by normalizing the incident height to the pupil by its maximum height (i.e., the relative pupil height).

[0078] In the aberration diagrams of FIGS. 6 to 8, the dashed line T represents the tangential image plane with respect to the d-line, expressed by the deviation amount (unit: 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 with respect to the d-line, expressed by the deviation amount (unit: mm) of the focal position in the optical axis AX direction from the paraxial image plane. The vertical axis represents the value obtained by normalizing the ray height at the image plane by its maximum image height (i.e., relative image height).

[0079] In the distortion aberration diagrams of FIGS. 6 to 8, the horizontal axis represents the distortion with respect to the d-line, expressed as the ratio of the actual image height to the ideal image height (unit: %), and the vertical axis represents the value obtained by normalizing the ray height at the image plane by its maximum image height (i.e., relative image height).

[0080] Numerical Example 1 Unit: mm Surface data Surface number r d 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 surface 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 Surface number r d 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 Comparative Example Unit: mm Surface data Surface number r d 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 of Numerical Example 1, Numerical Example 3, and the Numerical Comparative Example. Table 2 shows the conditional expression corresponding values of Numerical Example 1, Numerical Example 3, and the Numerical Comparative Example.

Table 1

Table 2

[0084] Figures 9 to 11 show the illuminance profiles on the light source side surface of the light shielding pattern layer 18 of the reticle 16 in Numerical Example 1, the Numerical Example, and the Numerical Comparative Example. In Figures 9 to 11, the horizontal axis represents the position (real image height) on the light source side surface of the light shielding pattern layer 18 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 in Numerical Example 1, the Numerical Example, and the Numerical Comparative Example. In the illuminance profiles of Figures 12 to 14, the horizontal axis represents the position (real image height) on the light receiving surface of the optical sensor 39 from the optical axis, and the vertical axis represents the light intensity at that position.

[0085] From FIGS. 9 to 11, in Numerical Example 1 and Numerical Example 2, it can be seen that the area between the illuminance profile and the horizontal axis is increased compared with the numerical comparative example, the peak value of the illuminance profile is larger, and the illuminance profile rises more steeply. Similarly, from FIGS. 12 to 14, in Numerical Example 1 and Numerical Example 2, it can be seen that the area between the illuminance profile and the horizontal axis is increased compared with the numerical comparative 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 source side surface of the light shielding pattern layer 18 of the reticle 16 is increased compared with the numerical comparative 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 with the numerical comparative example. In Numerical Example 1 and Numerical Example 2, the utilization efficiency of the light emitted from the light source is improved compared with the numerical comparative example.

[0086] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present disclosure is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0087] 1 Three-dimensional scanner, 2 Handpiece, 3, 3b Objective optical system for three-dimensional scanner, 10 Housing, 13 Light source, 13a Light emitting surface, 14 Illumination optical system for three-dimensional 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 Moving 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, comprising an illumination lens system, and a reticle disposed on the object side with respect to the illumination lens system, wherein the illumination lens system includes, in order from the light source side to the object side, a first lens having a positive power, and a second lens having a positive power, the first lens being a biconvex lens, the light source side surface of the second lens being an aspherical surface, the reticle including a light-shielding pattern layer, and satisfying the following conditional expressions (1) and (2); 3.0 < |b / a| < 5.0... (1) 0.03 < |c / d| < 0.09... (2) where a: the focal length of the first lens, b: the focal length of the second lens, c: the height of the light-emitting surface of the light source from the optical axis, d: the 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, and

2. The illumination optical system for a three-dimensional scanner according to claim 1, satisfying the following conditional expression (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. The illumination optical system for a three-dimensional scanner according to claim 1, satisfying the following conditional expression (4); e ≤ 3.0 …(4) However, e: The distance on the optical axis between the light source side surface of the first lens and the light emitting surface of the light source is.

6. A three-dimensional scanner comprising the illumination optical system for a three-dimensional scanner according to any one of Claims 1 to 5.

Images