JP7039902B2 - Multifocal lens, measuring device and measuring method - Google Patents

Description

The present invention relates to a multifocal lens, a measuring device and a measuring method.

Patent Document 1 includes a projection optical system having an outward optical axis for projecting measurement light and a light receiving optical system having a return optical axis for receiving reflected light. A light receiving lens for the light receiving optical system to receive and collect the reflected light, a light receiving surface on which the reflected light is incident, and a ring-shaped perforated multifocal optical member arranged between the light receiving surface and the light receiving lens. A light wave distance measuring device characterized by having the above is disclosed. In the light wave distance measuring device disclosed in Patent Document 1, the measured light passes through the hole of the light receiving lens, and the reflected light passes through the hole of the light receiving lens and the lens.

Patent Document 2 includes a solid-state image sensor, at least two lenses, and a diaphragm that limits light rays, and one of the lenses has a plurality of focal lengths on the light incident side of the solid-state image sensor. There is disclosed an image pickup device that is a multifocal lens and the diaphragm is on the light incident side of the multifocal lens. In the image pickup apparatus disclosed in Patent Document 2, a diaphragm is arranged between two lenses, and one of the lenses is a bifocal lens, but the distance between the lens and the diaphragm is the focal length of the lens. Is different.

Japanese Unexamined Patent Publication No. 2004-069611 Japanese Unexamined Patent Publication No. 2007-108600

An object of the present invention is to improve the measurement accuracy in a measuring device using an optical system including two lenses and a diaphragm provided between them as compared with the case of using a single focus lens alone.

In order to achieve the above object, the measuring device according to claim 1 has a first light emitting unit that emits irradiation light to irradiate an object and a first light emitting unit that changes the degree of emission of the irradiation light emitted from the light emitting unit. The lens, the aperture portion that narrows down the irradiation light emitted from the first lens, and the irradiation light that has passed through the aperture portion are applied onto the object so as to irradiate the object from a predetermined direction. A first optical element that collects light, a light receiving unit that is arranged between the throttle unit and the first optical element, and receives the reflected light that is reflected by the irradiation light irradiating the object, and the above. It includes a second optical element that irradiates and reflects the irradiation light on the object and collects the reflected light received by the light receiving portion on the light receiving surface of the light receiving portion.

The invention according to claim 2 is the invention according to claim 1, wherein the second optical element is a second lens having a first focal length, and the first optical element is a second lens. One of the correction element and the second optical element, which is composed of a correction element that transmits the irradiation light and corrects the first focal length and a part of the second optical element that transmits the irradiation light. The focal length of the portion is the center of the aperture portion.

Further, in the invention according to claim 3, in the invention according to claim 2, the light emitting unit includes a plurality of light emitting elements arranged in a predetermined direction, and the first optical element is defined in advance. It is stretched in the direction in which it is formed and has a length that allows irradiation light from each of the plurality of light emitting elements to be transmitted.

Further, in the invention of claim 1, the first optical element and the second optical element are integrally configured as a multifocal lens in the invention of claim 1, and the first optical element is described. Is the first region of the multifocal lens whose focal position is the center of the aperture portion, and the second optical element has a focal distance for condensing the reflected light on the light receiving surface. This is the second area of the multifocal lens.

Further, in the invention according to claim 5, the first region and the second region have different refractive indexes from each other in the invention according to claim 4.

Further, in the invention according to claim 6, in the invention according to claim 4, the first region and the second region have different surface curvatures from each other.

The invention according to claim 7 is the invention according to any one of claims 4 to 6, wherein the light emitting unit includes a plurality of light emitting elements arranged in a predetermined direction. The first region is stretched in the predetermined direction and has a length for transmitting the irradiation light from each of the plurality of light emitting elements.

Further, the invention according to claim 8 is the invention according to any one of claims 4 to 7, wherein a light-shielding member is provided between the first region and the second region. be.

In order to achieve the above object, the measurement method according to claim 9 includes a light emitting unit that emits irradiation light to irradiate an object, a lens that changes the degree of emission of the irradiation light emitted from the light emitting unit, and the like. A measurement method using a measuring device including a throttle portion that narrows down the irradiation light emitted from the lens and a light receiving portion that receives the reflected light that is reflected by the irradiation light that has passed through the throttle portion and is applied to the object. Therefore, the irradiation light is focused on the object so that the irradiation light passing through the throttle portion by the first optical element is irradiated to the object from a predetermined direction, and the second The irradiation light is irradiated to the object and reflected by the optical element of the above, and the reflected light received by the light receiving unit is condensed on the light receiving surface of the light receiving unit.

In order to achieve the above object, the multifocal length lens according to claim 10 has a first focal length having a first focal length and the first focal length having a flat shape extended in a predetermined direction. A second region having a second focal length different from that of the first region is included, and in a plan view, the second region is formed by being included in the first region, or is formed in the predetermined direction. Both ends are formed so as to overlap a part of the peripheral edge of the first region.

The invention according to claim 11 is the invention according to claim 10, wherein the interface between the first region and the second region is in advance with respect to the optical axis of the multifocal lens in a cross-sectional view. It is tilted at a fixed angle.

Further, the invention according to claim 12 transmits the multifocal lens bidirectionally between the first region and the second region in the invention according to claim 10 or 11. It further includes a light-shielding portion that shields light from each other.

According to the inventions of claims 1, 9 and 10, a case where a single focal length lens is used in a measuring device using an optical system including two lenses and a diaphragm provided between them is used. The effect of improving the measurement accuracy can be obtained in comparison.

According to the second aspect of the present invention, there is an effect that the cost is further reduced as compared with the case where the first optical element and the second optical element are integrally configured as a multifocal lens. ..

According to the third aspect of the present invention, the size of the first optical element is larger than that of the case where the first optical element is not considered in consideration of the stretching direction and the length for transmitting the irradiation light from the light emitting element. Is suppressed.

According to the invention of claim 4, the first optical element is composed of a part of a correction element that transmits irradiation light and corrects a first focal length, and a second optical element that transmits irradiation light. The effect of reducing the number of parts can be obtained as compared with the case of doing so.

According to the fifth aspect of the present invention, the multifocal lens is a lens having a general shape as compared with the case where the first region and the second region are configured so that the curvatures of the surfaces are different from each other. The effect of

According to the sixth aspect of the present invention, there is an effect that the material of the lens is homogenized as compared with the case where the first region and the second region are configured to have different refractive indexes from each other. Be done.

According to the invention of claim 7, the size of the first region is larger than that of the case where the first region is formed without considering the stretching direction and the length for transmitting the irradiation light from the light emitting element. The effect of being suppressed is obtained.

According to the eighth aspect of the present invention, there is an effect that the interference between the irradiation light and the reflected light is suppressed as compared with the case where the light shielding member is not provided between the first region and the second region. can get.

According to the invention of claim 11, the interface between the first region and the second region is attached to the multifocal lens as compared with the case where the interface between the first region and the second region is parallel to the optical axis of the multifocal lens in the cross-sectional view. The effect of improving the efficiency of light transmission according to the incident direction of light can be obtained.

According to the twelfth aspect of the present invention, as compared with the case where the light shielding portion for blocking the light transmitted in both directions of the multifocal lens is not included between the first region and the second region. The effect of suppressing interference between light transmitted in both directions through the multifocal lens can be obtained.

It is sectional drawing which shows an example of the structure of the measuring apparatus which concerns on 1st Embodiment. (A) is a plan view showing an example of the configuration of the light receiver according to the embodiment, and (b) is a graph showing the light quantity output characteristics of the light receiver. The operation of the measuring device according to the first embodiment will be described, (a) is a view seen from a direction orthogonal to the arrangement direction of the light emitting elements, and (b) is a view showing the details of the lens on the object side, ( c) and (d) are views viewed from a direction parallel to the arrangement direction of the light emitting elements. (A) is a view of the multifocal lens according to the first embodiment seen from above of the measuring device, and (b) is a view of the multifocal lens according to the modified example seen from above of the measuring device. It is sectional drawing which shows an example of the structure of the measuring apparatus which concerns on 2nd Embodiment. It is sectional drawing which shows an example of the structure of the measuring apparatus which concerns on 3rd Embodiment. (A) to (c) are diagrams for explaining the operation of the measuring device according to the comparative example, and (d) is a diagram showing a modified example of the diaphragm.

[First Embodiment]
The multifocal lens, the measuring device, and the measuring method according to the present embodiment will be described in detail with reference to FIGS. 1 to 4. First, an example of the configuration of the measuring device 10 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 shows a configuration when the measuring device 10 measures an object.

As shown in FIG. 1, the measuring device 10 includes a light emitter 14, an optical system 30, and a light receiver 18. The measuring device 10 sequentially irradiates the fine region of the object OB moving in the −X direction with light from the Z-axis direction, and acquires the reflection angle distribution (reflection angle dependence of the light amount distribution) of the reflected light for each irradiation light. .. Using the acquired reflection angle distribution, changes in the shape of the object OB and changes in the surface condition (texture, embossing, surface roughness, surface defects, foreign matter adhesion, etc.) with respect to the object OB and the angle of the object OB. Measurement is done without being affected by.

More specifically, as shown in FIG. 1, the light emitter 14 is arranged above the device vertical direction (Z-axis direction) with respect to the measurement region T through which the object OB moving in the −X direction passes. There is. Further, the light emitters 14 are mounted side by side on the substrate 14A in the Y-axis direction, and include a plurality of light emitting elements 12 having the −Z direction as the light emitting direction. In other words, the plurality of light emitting elements 12 are arranged in a direction orthogonal to (intersecting) the moving direction (−X direction) of the object OB. In FIG. 1, the light emitting element 12 arranged at one end of the substrate 14A in the Y-axis direction (right end in the figure) is referred to as a light emitting element 12A, and is designated as the other end of the substrate 14A in the Y-axis direction (left end in the figure). The arranged light emitting element 12 is referred to as a light emitting element 12B, and the light emitting element 12 arranged in the center of the substrate 14A is referred to as a light emitting element 12C.

The plurality of light emitting elements 12 according to the present embodiment are configured to sequentially emit light from the light emitting element 12A to the light emitting element 12B with a time difference, and the light from each light emitting element 12 is located at a different position on the object OB. It is individually irradiated. Then, while the object OB moves in the −X direction in the measurement region T, one cycle of light emission from the light emitting element 12A to the light emitting element 12B is repeated a plurality of times.

The light emitting element 12 is not particularly limited, but as an example, a surface emitting laser (Vertical Cavity Surface Emitting Laser: VCSEL), a light emitting diode (Light Emitting Diode: LED), or the like is used.

The optical system 30 includes a lens 32, a lens 34, and a diaphragm 40 arranged between the lens 32 and the lens 34, and is configured as a so-called bilateral telecentric lens. The optical system 30 is arranged between the light emitter 14 and the object OB, guides the irradiation light emitted from the light emitting element 12 to the object OB, and transfers the reflected light reflected by the object OB to the light receiver 18. Guide.
That is, the light receiver 18 is configured so that the irradiation light emitted from the light emitting element 12 emitted from the lens 34 is reflected by the object OB and receives at least a part of the light flux transmitted through the lens 34 again. Further, in the present embodiment, the optical axis of the lens 32 and the optical axis of the lens 34 are a common optical axis M, and this optical axis M is the center of the light emitting element 12C of the light emitter 14 and the aperture 40 described later. It passes through the center of the opening 42 of.

The lens 32 is, for example, a circular plano-convex lens in a plan view, and the diameter of the lens 32 is longer than the dimension in the Y-axis direction from the light emitting element 12A to the light emitting element 12B. Therefore, almost all of the light emitted from each light emitting element 12 passes through the lens 32, and the light transmitted through the lens 32 has a different degree of divergence and is regarded as parallel light toward the lens 34.

The lens 34 is, for example, a circular plano-convex lens in a plan view, and in the present embodiment, the diameter of the lens 34 is longer than the diameter of the lens 32. Then, the lens 34 collects the light beam (irradiation light) emitted from the lens 32 and transmitted through the lens 34 toward the surface 200 of the object OB, and the irradiation light reflects the reflected light on the object OB. Focuses on the light receiving element 16. The lens 34 is a multifocal lens, and in the present embodiment, it is a bifocal lens as an example. That is, it has a first lens unit 34a having a focal length of f1 and a second lens unit 34b having a focal length of f2. In the present embodiment, the focal length f1 is equal to the distance between the lens 34 and the center of the aperture 40 described later, and the focal length f2 is equal to the distance between the lens 34 and the light receiving surface of the light receiving element 16 described later. .. The first lens portion 34a and the second lens portion 34b are configured, for example, by forming regions having different refractive indexes in the lens 34 or by forming regions having different curvatures on the surface of the lens 34. When the difference in the refractive index is used, the shape of the lens 34 is a general shape, and when the difference in the curvature is used, the material of the lens is homogenized. You can choose either one in consideration of it. The details of the lens 34 will be described later.

A substantially circular opening 42 is formed in the aperture 40, and the opening 42 narrows the light beam emitted from the light emitting element 12 and transmitted through the lens 32 to be incident on the lens 34. More specifically, the diaphragm 40 has a plate shape whose plate surface is parallel to the XY plane, and the circular shape formed by the opening 42 has the optical axis M as the central axis. Then, in the Z-axis direction, the distance between the center of the opening 42 and the lens 32 is substantially equal to the focal length of the lens 32, and the distance between the center of the opening 42 and the lens 34 is the focal length of the lens 34. It is almost equal.

The light receiver 18 includes a plurality of light receiving elements 16 and receives reflected light RF (see FIG. 3D) that is reflected by the object OB and transmitted through the lens 34 of the optical system 30. The light receiver 18 according to the present embodiment is arranged on the lower side in the Z-axis direction of the diaphragm 40 arranged between the lens 32 and the lens 34. The light receiving element 16 is not particularly limited, but for example, a photodiode (Photodiode: PD), a charge coupling element (Charge-Coupled Device: CCD), or the like is used.

FIG. 2A shows an example of the configuration of the receiver 18. FIG. 2A is a plan view of the receiver 18 as viewed from the Z-axis direction. The receiver 18 shown in FIG. 1 represents a cross-sectional view taken along the line XX'of FIG. 2 (a). As shown in FIG. 2A, as an example, the photoreceiver 18 has a plurality of light receiving elements 16 (in FIG. 2A) on a substantially circular substrate 18A having a substantially circular opening 18B in the center. 60 examples are shown) are arranged in a plane (array). In the measuring device 10, the entire light receiving element 16 is used as the light receiving region RA to receive the reflected light RF.

As an example, the range of the reflected light RF received in the light receiving region RA is the reflected light RF in the range of an angle of 0 ° to 40 ° about the axis parallel to the optical axis M. When this reflected light RF is received in the light receiving region RA, a three-dimensional distribution is formed by the amount of light received by each light receiving element 16. When the reflected light RF is isotropic as in the case of being reflected on the perfect diffusion surface, the shape of the cross section of this three-dimensional distribution cut by the plane including the Z axis is shown in FIG. 2 (b). As shown, it becomes a substantially Gaussian curve.
The light receiving element numbers 1 to 6 on the horizontal axis of FIG. 2B correspond to the light receiving element numbers 1 to 6 shown in FIG. 2A. Further, since the reflected light RF is not received between the light receiving element 16 and the light receiving element 16 in the light receiving region RA, the actual output distribution is discrete, but this is omitted in FIG. 2 (b). There is.

Next, the operation of the measuring device 10 will be described with reference to FIG. 3A is a view of the measuring device 10 from the same direction as that of FIG. 1, and FIGS. 3C and 3D are views of the measuring device 10 viewed from a direction different from that of FIG. 1 by 90 °. On the other hand, FIG. 3 (b) shows the details of the lens 34 when viewed from the same direction as in FIGS. 3 (c) and 3 (d).

As shown in FIG. 3A, the light emitting element 12 mounted on the light emitter 14 sequentially emits light in the −Y direction (denoted as direction D1 in FIG. 2) as an example. In the optical system 30, the luminous flux from each light emitting element 12 that is sequentially emitted is narrowed down regardless of the position of the light emitting element 12 and is used as an irradiation light IF parallel to the optical axis M in the + Y direction (direction D2 in FIG. 2). (Notation) sequentially irradiates the object OB. At this time, the irradiation light IF passes through the first lens portion 34a of the lens 34. That is, the irradiation light IF is focused on the object OB by the first lens unit 34a.

In other words, by causing each light emitting element 12 to emit light and scanning, a substantially circular light flux (spot) narrowed down and parallel to each other is individually irradiated to the object OB. Further, in the measuring device 10 according to the present embodiment, by arranging the object OB near the condensing point of the light flux of the irradiation light IF by the lens 34, the irradiation region of each irradiation light IF in the object OB is substantially the same. It is considered to be a region with a fine diameter. As a result, in the measuring device 10, even if the position of the object OB fluctuates up and down in the Z-axis direction, each irradiation light is irradiated with almost the same irradiation diameter, so that the blur of the image of the object OB is extremely reduced. To. In addition, in this embodiment, in order to avoid the complexity of the illustration, the actual ratio such as the focal length is not always expressed.

Since the light emitting elements 12 are arranged in the Y-axis direction on the light emitter 14, the irradiation light IF is constant when viewed from the Y-axis direction even if the light emitting elements 12 emit light sequentially as shown in FIG. 3 (c). appear. That is, since the irradiation light IF has a relatively thin luminous flux, the proportion of the first lens unit 34a in the lens 34 is also small. Further, as shown in FIG. 3B, the interface between the first lens portion 34a and the second lens portion 34b according to the present embodiment (hereinafter referred to as “interface”; “side surface” of the first lens portion 34a. It can be said that) is tilted by a predetermined angle θ with respect to the optical axis M (see also FIG. 1) according to the tilt angle of the luminous flux of the irradiation light IF. The inclination of the angle θ may be provided over the entire circumference of the interface, or may be provided only at the interface in the longitudinal direction of the first lens portion 34a, for example. By tilting the side surface of the first lens portion 34a, the region of the second lens portion 34b is increased, and the transmission of the reflected light RF is made more efficient. The side surface of the first lens portion 34a does not necessarily have to be tilted with respect to the optical axis M, and may be parallel to the optical axis M.

FIG. 3D shows a state in which the reflected light RF reflected by the object OB is focused on the light receiving element 16 of the light receiver 18 (not shown in FIG. 3D). As shown in FIG. 3D, most of the reflected light RF passes through the second lens portion 34b having a focal length f2 and is focused on the light receiving surface of the light receiving element 16. In the present embodiment, the focal length f2 is f2 <focal length f1.

In the measuring device 10 configured as described above, the position of the object OB fluctuates up and down in the Z-axis direction or fluctuates left and right in the Y-axis direction, and irradiation light IFs from different light emitting elements are irradiated. Even if this is done, the output distribution in the light receiving region RA is always constant as long as the irradiation position on the object OB is the same. In other words, assuming a small region as large as the irradiation diameter as the object OB, if the object OB moves up and down in the Z-axis direction or left and right in the Y-axis direction, different light emitting elements 12 In the measuring device 10 according to the present embodiment, the output distribution by the entire light receiving element 16 included in the light receiving region RA is the reflected light RF. The output distribution is always the same regardless of the position where the light is generated.

Here, assuming that the position of the lower surface of the diaphragm 40 in the Z-axis direction is S1 and the position of the light-receiving surface of the light-receiving element 16 in the Z-axis direction is S2, the positions S1 and S2 are different in the measuring device 10. The reason for this is that, as shown in FIG. 1, in the present embodiment, the light receiver 18 is arranged on the lower surface of the diaphragm 40. In a measuring device as in the present embodiment, it is preferable that the distance between the aperture 40 and the lens 34 and the distance between the light receiving surface of the light receiving element 16 and the lens 34 are both the focal lengths of the lens 34. However, in the present embodiment, it is difficult to set the focal length of the lens 34 in this way due to the above mounting reasons.

The above points will be described in more detail with reference to FIG. 7. FIG. 7A shows a measuring device 100 according to a comparative example. Since the measuring device 100 is the same as the measuring device 10 shown in FIG. 1 except that the lens 34 is changed to the single focus lens 50, the same reference numerals are given to the same configurations, and detailed description thereof will be omitted. FIG. 7B shows a state in which the reflected light RF advances to the light receiving element 16 via the lens 50, and FIG. 7C shows the arrangement relationship between the aperture 40 of the measuring device 100 and the light receiving element 16. ..

As shown in FIGS. 7A and 7B, in the measuring device 100, the position S1 in the Z-axis direction of the bottom surface of the diaphragm 40 and the position S2 in the Z-axis direction of the light receiving surface of the light receiving element 16 are different. FIG. 7 (c) shows an enlarged view of this difference, and as shown in FIG. 7 (c), the position S1 and the position S2 differ by the height difference Δh. Therefore, the focal length of the lens 50 must be set according to either the distance from the aperture 40 to the lens 50 or the distance from the light receiving surface of the light receiving element 16 to the lens 50. For example, if the focal length of the lens 50 is adjusted to the distance from the aperture 40 to the lens 50, the measurement accuracy of the measuring device 100 is lowered. That is, as described above, in the light receiver 18 shown in FIG. 2A, light originally reflected at different positions is received by the same light receiving element 16 at the same angle, but this accuracy is inadequate. Since it is sufficient, the angular resolution at this time is reduced.

As a configuration for avoiding the above phenomenon, a configuration using a diaphragm 44 as shown in FIG. 7D is also conceivable. As shown in FIG. 7D, the diaphragm 44 is provided with a bent portion 46, and the tip of the bent portion 46 is configured to be an opening 48 flush with the light receiving surface of the light receiving element 16. With such a configuration, the distance between the aperture 44 and the lens 50 is equal to the distance between the light receiving surface of the light receiving element 16 and the lens 50. However, in the case of the main aperture 44, there is a demerit that the light receiving element 16 cannot be arranged at the bent portion 46 having the length Δd.

In order to avoid the above phenomenon, the lens 34 is a multifocal lens in the measuring device 10 according to the present embodiment. Then, as described above, the focal length f1 of the first lens unit 34a is equal to the distance between the lens 34 and the center of the aperture 40, and the focal length f2 of the second lens unit 34b is the lens 34 and the light receiving element 16. Is equal to the distance from the light receiving surface. As a result, in the measuring device 10, the optical system 30 is used as a telecentric optical system, and the reflected light RF reflected by the object OB is focused on the light receiving surface of the light receiving element 16. Therefore, since the reflected light RF reflected by the object OB is always incident on the light receiving surface of the light receiving element 16 in a state of being in focus, the measuring device 10 is compared with the case where the lens 34 is a single focus lens. Measurement accuracy is improved.

Next, with reference to FIG. 4, the transmission region of the irradiation light IF and the reflected light RF in the lens 34 will be described in more detail. FIG. 4A is a plan view of a part of the measuring device 10 as viewed from above in the Z-axis direction. In FIG. 4A, <1> is the transmission of the irradiation light IF, and <2> is the reflected light RF. Shows transparency. As shown in FIG. 4A <1>, in the present embodiment, a substantially rectangular region extended in the diameter direction of the substantially circular lens 34 is designated as the first lens portion 34a, and the remaining region thereof. Is the second lens portion 34b. The light emitting element 12 arranged in the light emitting device 14 is arranged at a position where the irradiation light IF passes through the first lens portion 34a.

On the other hand, as shown in <2> of FIG. 4A, the reflected light RF is isotropically reflected from the reflection point on the object OB as described above, so that the distribution has a substantially circular shape in a plan view. Mainly transmits through the second lens portion 34b of the lens 34. At this time, a part of the reflected light RF passes through the first lens portion 34a, but most of the reflected light RF at this angle is directed toward the opening 42 of the aperture 40, so that the light received by the receiver 18 is large. It has no effect.

FIG. 4 (b) shows a lens 34A which is a modification of the lens 34. Similar to FIG. 4 (a), FIG. 4 (b) <1> is transmission of irradiation light IF, and <2> is reflected light. It shows the transmission of RF. The shape of the first lens portion 34Aa is different between the lens 34A and the lens 34. That is, the first lens portion 34a of the lens 34 is stretched to the peripheral edge portion of the lens 34, and both ends in the stretching direction overlap the peripheral edge portion of the lens 34. On the other hand, the first lens portion 34Aa of the lens 34A includes the lens 34A, and both ends in the stretching direction do not reach the peripheral edge of the lens 34A. As described above, the first lens portion 34a or 34Aa has a size occupied by the first lens portion 34a or 34Aa with respect to the lens 34 or 34A, except that the irradiation light IF from the light emitting element 12 is transmitted. There are no particular restrictions on this. Further, since the first lens portion 34a or 34Aa may have a shape that allows the irradiation light IF from the light emitting element 12 to be transmitted, the first lens portion 34a or 34Aa is not limited to a rectangular shape, but may be a flat ellipse, a rhombus, or the like, depending on the lens design or the like. You may choose the appropriate shape.

[Second Embodiment]
The measuring device 10A according to the present embodiment will be described with reference to FIG. The measuring device 10A is a form in which the lens 34 of the measuring device 10 is replaced with the lens 34B. Therefore, the same reference numerals are given to the same configurations, and detailed description thereof will be omitted.

As shown in FIG. 5A, the lens 34B according to the present embodiment includes a first lens portion 34Ba having a focal length of f1 and a second lens portion 34Bb having a focal length of f2. A light-shielding portion 34Bc is provided at the interface between the lens portion 34Ba and the second lens portion 34Bb. The light-shielding portion 34Bc is, for example, a separate body of the first lens portion 34Ba and the second lens portion 34Bb, and reflects a metal film or the like on one or both sides of the first lens portion 34Ba and the second lens portion 34Bb. It is formed by depositing members. The measuring device 10A according to the present embodiment is a suitable embodiment when there is a concern about interference between the irradiation light IF and the reflected light RF in the lens 34 or 34A according to the above embodiment.

[Third Embodiment]
The measuring device 10B according to the present embodiment will be described with reference to FIG. In this embodiment, a single focus lens and a correction element are used instead of the multifocal lenses 34 (lenses 34A and 34B) according to each of the above embodiments. Therefore, the same reference numerals are given to the same configurations as those of the measuring devices according to the above embodiments, and detailed description thereof will be omitted.

As shown in FIGS. 6A and 6B, the measuring device 10B includes a lens 60 and a correction element 62. The lens 60 is a single focus lens, and the focal length f2 of the lens 60 is the distance between the lens 60 and the light receiving surface of the light receiving element 16. In this case, the distance between the aperture 40 and the lens 60 is longer than the focal length f2 by the height difference Δh. Therefore, the correction element 62 is provided. That is, the correction element 62 sets the focal length of the region of the lens 60 through which the irradiation light IF from the light emitting element 12 is transmitted from the focal length f2 of the lens 60 to the focal length f1 which is the distance between the lens 60 and the center of the aperture 40. It has a function to change to.

Also in the measuring device 10B according to the present embodiment, the optical system 30 is a telecentric optical system, and the reflected light RF receives light at a reflection angle that should be originally received by the light receiving surface of the light receiving element 16. The measurement accuracy is further improved as compared with the case of using a single focus lens alone. According to the measuring device 10B according to the present embodiment, since a single focus lens and a simple correction element are sufficient, the cost is reduced as compared with the case where a multifocal lens is used. Further, since the correction element may be changed, it is easier to change the focal length.

In this embodiment, the embodiment of correcting the focal length of the region through which the irradiation light IF of the lens 60 is transmitted has been described as an example, but the present invention is not limited to this, and the focal length of the region through which the reflected light RF is transmitted is corrected. It may be in the form. In this case, the focal length of the lens 60 is equal to the distance between the center of the aperture 40 and the lens 60.

10, 10A, 10B Measuring device 12, 12A, 12B, 12C Light emitting element 14 Light emitting device 14A Substrate 16 Light receiving element 18 Light receiving element 18A Board 18B Opening 30 Optical system 32 Lens 34, 34A, 34B Lens 34a, 34Aa, 34Ba 1st Lens part 34b, 34Ab, 34Bb Second lens part 34Bc Light-shielding part 40 Aperture 42 Opening 44 Aperture 46 Bending part 48 Opening 50 Lens 60 Lens 62 Correcting element 100 Measuring device 200 Surface D1, D2 direction f1, f2 Focus distance IF Irradiation light M Optical axis RF Reflected light OB Object RA Light receiving area S1, S2 Position T Measurement area Δh Height difference

Claims (11)

A light emitting part that emits irradiation light that irradiates an object,
A first lens that changes the degree of divergence of the irradiation light emitted from the light emitting portion, and
A diaphragm portion that narrows down the irradiation light emitted from the first lens, and a diaphragm portion.
A first optical element that collects the irradiation light that has passed through the diaphragm portion onto the object so as to irradiate the object from a predetermined direction.
A light receiving portion arranged between the diaphragm portion and the first optical element and receiving the reflected light reflected by the irradiation light irradiating the object.
A measuring device including a second optical element that irradiates and reflects the irradiation light on the object and collects the reflected light received by the light receiving portion on the light receiving surface of the light receiving portion. The second optical element is a second lens having a first focal length.
The first optical element is composed of a correction element that transmits the irradiation light and corrects the first focal length, and a part of the second optical element that transmits the irradiation light. The measuring device according to claim 1, wherein the focal length of a part of the second optical element is the center of the diaphragm portion. The light emitting unit includes a plurality of light emitting elements arranged in a predetermined direction.
The measuring device according to claim 2, wherein the first optical element is stretched in a predetermined direction and has a length for transmitting irradiation light from each of the plurality of light emitting elements. The first optical element and the second optical element are integrally configured as a multifocal lens.
The first optical element is a first region of the multifocal lens whose focal position is the center of the aperture portion.
The measuring device according to claim 1, wherein the second optical element is a second region of the multifocal lens having a focal length for condensing the reflected light on the light receiving surface. The measuring device according to claim 4, wherein the first region and the second region have different refractive indexes from each other. The measuring device according to claim 4, wherein the first region and the second region have different surface curvatures from each other. The light emitting unit includes a plurality of light emitting elements arranged in a predetermined direction.
The first aspect according to any one of claims 4 to 6, wherein the first region is stretched in the predetermined direction and has a length for transmitting irradiation light from each of the plurality of light emitting elements. Measuring device. The measuring device according to any one of claims 4 to 7, further comprising a light-shielding member between the first region and the second region. A light emitting part that emits irradiation light that irradiates an object,
A lens that changes the degree of divergence of the irradiation light emitted from the light emitting portion,
A diaphragm portion that narrows down the irradiation light emitted from the lens, and
It is a measurement method by a measuring device including a light receiving portion in which the irradiation light passing through the diaphragm portion irradiates the object and receives the reflected light.
The irradiation light is focused on the object so that the irradiation light passing through the diaphragm portion is irradiated to the object from a predetermined direction by the first optical element.
A measuring method in which the irradiation light is irradiated to the object by the second optical element, reflected, and the reflected light received by the light receiving unit is focused on the light receiving surface of the light receiving unit. The first region with the first focal length and
Includes a second region extending in a predetermined direction and having a second focal length different from the first focal length.
In a plan view, the second region is formed by being included in the first region, or both ends in a predetermined direction overlap with a part of the peripheral edge of the first region. It ’s a multifocal lens .
The interface between the first region and the second region is tilted at a predetermined angle with respect to the optical axis of the multifocal lens in a cross-sectional view.
Multifocal lens. The first region with the first focal length and
Includes a second region extending in a predetermined direction and having a second focal length different from the first focal length.
In a plan view, the second region is formed by being included in the first region, or both ends in a predetermined direction overlap with a part of the peripheral edge of the first region. It ’s a multifocal lens .
Between the first region and the second region, a light-shielding portion that shields light passing through the multifocal lens in both directions is further included.
Multifocal lens.

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