Light sensor

Abstract

The invention provides an optical sensor capable of reducing light intensity difference between a central part and a peripheral part of a light spot. A light sensor (1) is a distance setting type light sensor having a light source (5) that emits a Gaussian beam (A) and at least one distribution changing element (10). The at least one distribution changing element (10) is configured so as to change a Gaussian beam (A) emitted from the light source (5) to a beam (B) having a light intensity distribution other than the Gaussian pattern.

Description

Technical Field

[0001] The present invention relates to light sensors. Background Art

[0002] Optical sensors that use light reflection to detect missing parts in workpieces, for example, exist. When a workpiece has recesses or through-holes, the reflectivity of light varies locally. For example, when the workpiece is bottles arranged on a tray, deep valley-like gaps form between adjacent bottles. By increasing the size of the irradiating laser spot to be larger than the recess in the workpiece, even such workpieces can be stably detected. Patent Document 1 discloses a technique for changing the spot size by placing a flat plate between a laser diode and a light projection collimator to change the optical path length.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-78946 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Light emitted from a light source such as a laser diode has a Gaussian intensity distribution, with the center of the spot bright and the periphery dark. The technique described in Patent Document 1 simply enlarges the spot to maintain a Gaussian beam. Increasing the spot size results in a darker overall beam. Therefore, at the periphery, which is darker than the center, enlarging the spot size may not provide the required light intensity for workpiece detection. Insufficient light intensity may prevent accurate detection of the presence of a workpiece.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a photosensor capable of reducing the difference in light intensity between the central portion and the peripheral portion of a light spot.

[0009] Furthermore, as in the technology described in Patent Document 1, if multiple flat plates are arranged in a circular pattern on a converter holder serving as a rotating disk, the optical axis of the light beam becomes parallel to the rotation axis of the converter holder. Since the adjustment operation unit for rotating the converter holder is located on the back of the main body shell, it is difficult to visually confirm the optical axis while operating it. Furthermore, the light-emitting element serving as the light source is located in the space between the back of the main body shell and the converter holder. When the converter holder is a rotating disk, the shaft extending from the back of the main body shell to the adjustment operation unit of the converter holder becomes longer due to the space occupied by the light-emitting element. The longer the shaft becomes, the thicker it becomes in order to withstand the torque required to drive the converter holder. This makes it difficult to miniaturize the optical sensor.

[0010] Alternatively, as described in Japanese Patent Application Laid-Open No. 2001-264453, the shape of the light spot can be changed by moving the projection lens closer to or farther from the light source. However, in the technique described in Japanese Patent Application Laid-Open No. 2001-264453, the variable range of the light spot depends on the displacement of the projection lens along the optical axis. Increasing the variable range to the same degree as in Patent Document 1 requires more space for the mechanism that shifts the projection lens, making further miniaturization of the optical sensor difficult compared to the technique described in Patent Document 1.

[0011] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a compact optical sensor with excellent operability.

[0012] Means for solving problems

[0013] One embodiment of the optical sensor disclosed herein is a distance-setting optical sensor having a light source that emits a Gaussian beam and at least one distribution changing element, wherein the at least one distribution changing element is configured to change the Gaussian beam emitted from the light source into a beam having a light intensity distribution other than the Gaussian type.

[0014] According to this embodiment, a light beam with a Gaussian light intensity distribution (Gaussian beam) in which the center of the light spot is bright and the peripheral portion is dark can be changed to a light beam with a light intensity distribution other than Gaussian, thereby reducing the difference in light intensity between the center and peripheral portions of the light spot.

[0015] In the above-mentioned method, it may also be that at least one distribution change element is a plurality of distribution change elements including a first distribution change element and a second distribution change element, and the optical sensor is configured to be able to switch the shape of the light spot of the light beam with a light intensity distribution other than a Gaussian type by switching the first distribution change element and the second distribution change element.

[0016] In workpieces without recesses or through-holes, a smaller spot size is less likely to cause malfunction due to interference, enabling stable workpiece detection. On the other hand, in workpieces with recesses or through-holes, stable workpiece detection is possible even when the reflectivity of light in the recesses changes, increasing the spot size. There is a need to adjust the spot size to fit the workpiece. According to this method, by switching between the first and second distribution changing elements, the spot size can be adjusted to fit the workpiece.

[0017] In the above aspect, at least one distribution changing element may be configured to change a Gaussian beam emitted from a light source into a beam having a flat-top light intensity distribution.

[0018] In the above aspect, at least one distribution changing element may be configured to change a Gaussian beam emitted from the light source into a beam having a light intensity distribution in which the light intensity at the peripheral portion of the light spot is higher than that at the central portion.

[0019] Increasing the spot size results in a darker overall light intensity distribution. Therefore, in a Gaussian light intensity distribution where the center of the spot is bright and the periphery is dark, increasing the spot size at the periphery, which is darker than the center, may result in insufficient light intensity for workpiece detection. These methods make it easier to obtain the light intensity required for workpiece detection even at the periphery of the spot, enabling stable detection of workpieces.

[0020] The above aspect may further include a collimator that collimates the Gaussian beam emitted from the light source and causes the collimated beam to enter the at least one distribution changing element.

[0021] According to this embodiment, the intensity of the Gaussian beam incident on the distribution changing element or the beam emitted from the distribution changing element can be easily calculated, and thus the distribution changing element can be easily designed so as to have a desired spot shape.

[0022] In the above aspect, the optical sensor may be a TOF sensor, ie, a time-of-flight sensor, which measures distance based on the time it takes for a light beam projected at a fixed period to be reflected by a workpiece and returned.

[0023] When using a distance-setting optical sensor as a sensor for detecting the absence of a workpiece, the presence of the workpiece is detected by measuring the distance to the workpiece rather than the amount of light received. Therefore, it is not easily affected by the color or shape of the workpiece. Examples of distance-setting optical sensors include time-of-flight (TOF) sensors and triangulation distance sensors. Assuming that the axis along which the light-emitting and light-receiving components are arranged is the Y-axis and the axis along which the Gaussian light beam travels is the Z-axis, the triangulation distance sensor in a distance-setting optical sensor is well-matched with a line beam extending along the X-axis, allowing for stable detection of the presence of a workpiece even if the size of the line beam's light spot increases. A TOF sensor in a distance-setting optical sensor is well-matched not only with a line beam but also with light spots of various shapes, including circular and rectangular shapes, allowing for stable detection of the presence of a workpiece even if the size of the light spot increases. Because the shape of the light spot is not restricted, a TOF sensor is particularly preferred among distance-setting optical sensors. This method makes it easy to obtain the light intensity required for workpiece detection even at the periphery of the light spot, making TOF sensors particularly suitable.

[0024] In the above-mentioned method, the distribution changing element may also be a microlens array including a plurality of spherical lenses or a plurality of cylindrical lenses, which is configured to overlap with each other and change the Gaussian beams emitted from the light source and passing through each of the plurality of spherical lenses or each of the cylindrical lenses to a beam having a light intensity distribution other than the Gaussian type.

[0025] In the above aspect, the distribution changing element may be a diffractive optical element configured to diffuse a Gaussian beam emitted from a light source and change the beam into a beam having a light intensity distribution other than a Gaussian distribution.

[0026] In the above embodiment, the distribution changing element may be a multi-stage lens system comprising at least one concave lens and at least one convex lens, configured to cause a Gaussian beam emitted from the light source to diverge through the at least one concave lens and converge through the at least one convex lens, thereby changing the beam to a beam having a light intensity distribution other than a Gaussian distribution. In this case, some or all of the convex lenses may be formed from liquid lenses.

[0027] According to these aspects, it is possible to configure a distribution changing element that changes a Gaussian beam emitted from a light source into a beam having a light intensity distribution other than a Gaussian beam using readily available and inexpensive components.

[0028] Another aspect of the present disclosure includes a light source and a variable light spot mechanism configured to change the shape of the light beam's spot by switching optical elements arranged in the optical path of the light beam emitted from the light source. The variable light spot mechanism includes a plurality of optical elements arranged linearly along a first direction intersecting the direction of travel of the light beam, and a linear motion mechanism capable of linearly reciprocating the plurality of optical elements along the first direction.

[0029] This method uses a direct-acting mechanism to linearly move the multiple optical elements rather than rotating them using a rotary mechanism. This prevents the optical axis from being parallel to the rotation axis. This allows the adjuster to be operated while visually checking the optical axis. Furthermore, compared to existing technologies that require shifting the projection lens or rotating a rotating disk, this facilitates miniaturization of the optical sensor. This results in a compact and user-friendly optical sensor.

[0030] In the above aspect, the linear motion mechanism may be a rack-and-pinion mechanism including a rack extending linearly along the first direction and a pinion meshing with the rack.

[0031] According to this aspect, the linear motion mechanism can be configured with a relatively small number of components including only the rack and the pinion.

[0032] In the above aspect, a housing for accommodating the light source may be further provided, and the pinion gear may be operated from a first surface of the housing in a second direction intersecting both the traveling direction and the first direction.

[0033] The above aspect may further include a housing that houses the light source and a display that can display information related to settings of the optical sensor, and the pinion gear can be operated from a first surface of the housing on which the display is disposed.

[0034] According to these aspects, the pinion gear can be operated from the first surface side where the optical axis can be visually confirmed, or the pinion gear can be operated from the first surface side where the display can be visually confirmed, and thus the workability is excellent.

[0035] In the above-mentioned method, the plurality of optical elements may include a first optical element and a second optical element, and the variable light spot mechanism may further include: a convex portion; a first concave portion, which is opposite to the convex portion when the first optical element is arranged on the optical path of the light beam; a second concave portion, which is opposite to the convex portion when the second optical element is arranged on the optical path of the light beam; and a force-applying component, which applies force to the convex portion, and the variable light spot mechanism may be configured such that, when the optical element arranged on the optical path of the light beam is switched from the first optical element to the second optical element, the force of the force-applying component is overcome to release the engagement between the first concave portion and the convex portion, and the force of the force-applying component is used to engage the second concave portion with the convex portion.

[0036] According to the above aspect, when a plurality of optical elements are switched, the convex portions engage with the corresponding concave portions of the respective optical elements, so that the operator can easily recognize that the optical elements are arranged at predetermined positions on the optical path.

[0037] Effects of the Invention

[0038] According to the present invention, it is possible to provide a photosensor capable of reducing the difference in light intensity between the central portion and the peripheral portion of a light spot.

[0039] Furthermore, according to the present invention, a compact optical sensor with excellent operability can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a diagram showing an example of a photosensor according to one embodiment of the present invention.

[0041] Figure 2 This is a perspective view showing an example of a switching mechanism for switching a plurality of distribution changing elements.

[0042] Figure 3A This is a diagram showing an example of the light intensity distribution of a Gaussian beam.

[0043] Figure 3B 1 is a diagram showing an example of the light intensity distribution of a light beam changed from a Gaussian beam, that is, a top-hat type light intensity distribution.

[0044] Figure 3C1 is a diagram showing an example of the light intensity distribution of a beam changed from a Gaussian beam, that is, a light intensity distribution in which the light intensity at the peripheral portion of the light spot is higher than that at the central portion.

[0045] Figure 4 This is a diagram showing an example of a distribution changing element using a microlens array.

[0046] Figure 5 Yes Figure 4 FIG. 1 is a diagram showing a modified example of the microlens array shown.

[0047] Figure 6 This is a diagram showing an example of a distribution changing element using a diffractive optical element.

[0048] Figure 7 This is a diagram showing an example of a distribution changing element using a multi-stage lens.

[0049] Figure 8 It is a cross-sectional view showing an example of a photosensor according to a second embodiment of the present invention.

[0050] Figure 9 Observed from the front Figure 8 A perspective view of an example of a light spot variable mechanism shown.

[0051] Figure 10 Observed from behind Figure 8 A perspective view of an example of a light spot variable mechanism shown.

[0052] Figure 11A It is a plan view showing an example of a pictogram indicating that the shape of the light spot is a focused type and an example of a pictogram indicating that the shape of the light spot is a normal type.

[0053] Figure 11B It is a plan view showing an example of a pictogram indicating that the shape of the light spot is a diffusion type and an example of a pictogram indicating that the shape of the light spot is a normal type. DETAILED DESCRIPTION

[0054] The preferred embodiment of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the components marked with the same reference numerals have the same or identical structure. Hereinafter, each structure will be described in detail with reference to the accompanying drawings. Figures 1 to 7 , as an example of an optical sensor 1, a TOF (Time of Flight) sensor is disclosed. This sensor measures distance based on the time it takes for a light beam B projected at a fixed period to be reflected by a workpiece W and returned. The optical sensor 1 is not limited to the illustrated example and may also be a distance-setting optical sensor other than the TOF method. Examples of distance-setting optical sensors other than the TOF method include triangulation sensors.

[0055] like Figure 1 As shown, the optical sensor 1 includes a light projector 2, a light receiver 3, and a circuit board 4. The light projector 2 includes a light source 5 and projects a light beam B toward a workpiece W. The light receiver 3 includes a light receiving element such as a CMOS image sensor and receives the light beam B reflected by the workpiece W. The circuit board 4 is connected to the light projector 2 and the light receiver 3 and calculates the distance between the optical sensor 1 and the workpiece W by measuring the time it takes for the light beam B projected from the light projector 2 to be reflected by the workpiece W and return.

[0056] In addition to the light source 5, the light projection unit 2 also includes at least one distribution changing element 10. As an optional configuration, it may include a collimator 6 disposed between the light source 5 and the distribution changing element 10, a switching mechanism 9 for switching between multiple distribution changing elements 10, and the like. The light source 5 is a laser diode or the like, and emits a light beam A having a Gaussian light intensity distribution. The collimator 6 collimates the Gaussian light beam A emitted from the light source 5 and directs the collimated light beam into the distribution changing element 10. The distribution changing element 10 changes the Gaussian light beam A emitted from the light source 5 into a light beam B having a non-Gaussian light intensity distribution.

[0057] Reference Figures 4 to 7 As described in detail later, the distribution changing element 10 can be an optical element such as a microlens array 20 composed of multiple spherical lenses 21 or multiple cylindrical lenses 22. It can also be an optical element such as a diffraction grating 30. It can also be an optical element such as a multi-stage lens. The distribution changing element 10 can also be referred to as "an optical element that changes the Gaussian beam A emitted from the light source 5 into a beam B having a light intensity distribution other than Gaussian."

[0058] Figure 2 This is a perspective view showing an example of a switching mechanism 9 for switching between multiple distribution changing elements 10. The switching mechanism 9 includes, for example, a slider 91 having multiple distribution changing elements 10 arranged in series, a trimmer for operating the slider 91, rack and pinion mechanisms 93R and 93P for transmitting the rotation of the trimmer to the slider 91, and a frame 94 for slidably supporting the slider 91. In the illustrated example, the slider 91 is provided with the first to third distribution changing elements 10A to 10C. The structure of the switching mechanism 9 is not limited to the illustrated example; multiple distribution changing elements may also be arranged on a disk driven by a motor.

[0059] The first to third distribution changing elements 10A to 10C are each configured to change the Gaussian beam A emitted from the light source 5 into a beam B having a non-Gaussian light intensity distribution, and to cause the beam B to form a light spot S having a different shape. For example, by switching between the first distribution changing element 10A and the second distribution changing element 10B, the shape of the light spot S of the light beam B can be changed. The size of the light spot S can be increased or decreased depending on the workpiece W.

[0060] Figure 3A Graph showing an example of the light intensity distribution of Gaussian beam A. Figure 3B 1 is a diagram showing an example of the light intensity distribution of the light beam B changed from the Gaussian beam A, that is, a flat-top light intensity distribution. Figure 3C 1 is a diagram showing an example of the light intensity distribution of the light beam B after being changed from the Gaussian beam A, that is, a light intensity distribution in which the light intensity at the peripheral portion of the light spot S is higher than that at the central portion.

[0061] Figure 3A The light intensity distribution of the Gaussian beam A shown has a single peak. In contrast, Figure 3B and Figure 3C Light intensity distributions other than the Gaussian type shown have multiple peaks. For example, Figure 3B In the flat-top light intensity distribution shown, a plurality of peaks of substantially the same intensity continue. Figure 3B and Figure 3C Light intensity distributions other than the Gaussian type shown can reduce the difference in light intensity between the center and the peripheral portion of the light spot, compared to the Gaussian type light intensity distribution in which the center portion of the light spot is bright and the peripheral portion is dark.

[0062] Figure 4 1 is a diagram showing an example of the distribution changing element 10 using the microlens array 20 . Figure 5 Yes Figure 4 FIG. 2 is a diagram showing a modified example of the microlens array 20. Figure 4 In the example shown, the microlens array 20 is composed of a plurality of spherical lenses 21. Figure 5 As in the illustrated modification, the microlens array 20 is composed of a plurality of cylindrical lenses 22 .

[0063] The microlens array 20 is configured so that Gaussian beams A emitted from the light source 5 and passed through each of one or more cylindrical lenses 22 in the plurality of spherical lenses 21 overlap with each other and are changed into beams B having a light intensity distribution other than Gaussian.

[0064] When the microlens array 20 is composed of a plurality of spherical lenses 21, as shown in FIG. Figure 4 As shown, it can be changed into an elliptical (substantially circular) beam B with a small difference between the major diameter and the minor diameter, which is called a circular beam. When the microlens array 20 is composed of a plurality of cylindrical lenses 22, as shown in FIG. Figure 5 As shown, it can be changed to an elliptical (substantially linear) beam B with a large difference between the major axis and the minor axis, which is called a line beam. The shape of the spot S of the beam B is not particularly limited and may be rectangular or polygonal.

[0065] exist Figure 4In the example shown, a collimator 6 is disposed between the light source 5 and the microlens array 20, and the collimated Gaussian beam A is incident on each of the multiple spherical lenses 21 that constitute the microlens array 20. Since the intensity of the Gaussian beam A incident on each of the multiple spherical lenses 21 can be easily calculated, the microlens array 20 can be easily designed to achieve the desired shape of the light spot S.

[0066] Figure 6 1 is a diagram showing an example of a distribution changing element 10 using a diffractive optical element 30. Figure 6 As shown, a concavo-convex pattern of minute concave portions 31 and minute convex portions 32 is formed on the surface of the diffractive optical element 30 to diffuse the Gaussian beam A emitted from the light source 5. The diffractive optical element 30 is configured to diffuse the Gaussian beam A from the center toward the periphery, thereby converting the Gaussian beam A into a beam B having a light intensity distribution other than the Gaussian pattern, with a small difference in light intensity between the center and the periphery of the light spot S.

[0067] Figure 7 This figure shows an example of a distribution changing element 10 using a multistage lens 40. The multistage lens 40 is composed of at least one concave lens 41 and at least one convex lens 42. The multistage lens 40 is configured to diverge a Gaussian beam A emitted from the light source 5 by the at least one concave lens 41 and converge by the at least one convex lens 42, thereby changing the beam B to a beam having a non-Gaussian light intensity distribution. In the example shown, the convex lens 42 is formed of a liquid lens.

[0068] According to the optical sensor 1 of this embodiment configured as described above, the size of the light spot S can be changed, and the difference in light intensity between the center and the periphery of the light spot S can be reduced. Even at the periphery of the light spot S, the light intensity required for detecting the workpiece W can be easily obtained, enabling stable detection of the presence of the workpiece.

[0069] Next, refer to Figures 8 to 10 The second embodiment of the present invention will be described. The optical sensor 1 of the second embodiment has a light spot variable mechanism 9, which is configured to switch the shape of the light spot S of the light beam A emitted from the light source 5 by switching the optical elements 50A to 50C arranged on the optical path of the light beam A. The number of lenses is not limited to the example shown in the figure, and can be four or more, or two. In the second embodiment, each of the plurality of optical elements 50A to 50C is not limited to being configured as a distribution changing element 10 that changes the Gaussian light beam A emitted from the light source 5 into a light beam B having a light intensity distribution other than the Gaussian type, but may be an optical element that allows the Gaussian light beam A emitted from the light source 5 to pass through in the state of the Gaussian light beam A. In the example shown in the figure, the optical elements 50A to 50C are respectively composed of flat plate lenses of different plate thicknesses.

[0070] Figure 81 is a cross-sectional view showing an example of a light sensor according to a second embodiment of the present invention. Figure 8 As shown, the optical sensor 1 includes a housing 100 and a light projecting unit 2, a light receiving unit 3, a circuit board 4, etc. housed in the housing 100. The light projecting unit 2 is composed of a light source 5, a light spot variable mechanism 9, a light projecting lens 7, etc. In the example shown in the figure, the light projecting unit 2 does not have Figure 1 The collimator 6 is shown. The light spot variable mechanism 9 has substantially the same structure as the switching mechanism 9 described in the first embodiment.

[0071] The housing 100 is formed into a substantially rectangular parallelepiped having a front surface 101, a back surface 102, a top surface 105, a bottom surface 106, a left side surface, and a right side surface. Figure 1 shown) from the front side 101 toward the workpiece W ( Figure 1 A display 8 capable of displaying information related to the settings of the optical sensor 1 , an adjuster 92 for operating the light spot variable mechanism 9 , and the like are arranged on the top surface 105 .

[0072] Figure 9 Observed from the front Figure 8 The three-dimensional diagram of an example of the light spot variable mechanism 9 shown in FIG. Figure 9 As shown, the variable spot mechanism 9 includes a plurality of optical elements 50A to 50C linearly arranged along a first direction Y intersecting the direction X of travel of the light beam A, and a linear motion mechanism 93 capable of linearly reciprocating the plurality of optical elements 50A to 50C along the first direction Y. In the illustrated example, the linear motion mechanism 93 is a rack and pinion mechanism 93R and 93P, comprising a rack 93R extending linearly along the first direction Y and a pinion 93P meshing with the rack 93R.

[0073] Pinion gear 93P is configured to be operable from the top surface 105 of housing 100, which faces a second direction Z that intersects both the light traveling direction X and the first direction Y. The aforementioned display 8 is disposed on top surface 105. Top surface 105 is an example of a first surface. In the illustrated example, light traveling direction X is the front-to-back direction, first direction Y, which is the arrangement direction of optical elements 50A to 50C, is the left-to-right direction, and second direction Z, which intersects both the light traveling direction X and the first direction Y, is the up-down direction.

[0074] Furthermore, the structure of the direct-acting mechanism 93 is not limited to the rack-and-pinion mechanisms 93R and 93P. For example, a rod provided on the top surface 105 of the housing 100 can be moved in the first direction Y, thereby causing the optical elements 50A to 50C, driven by the movement of the rod, to reciprocate in the first direction Y. For example, a ball screw can be used. If a ball screw is used in which the nut reciprocates in the second direction Z, an operating unit such as an adjuster can be provided on the top surface 105 of the housing 100.

[0075] Figure 10 Observed from behind Figure 8 The three-dimensional diagram of an example of the light spot variable mechanism 9 shown in FIG. Figure 10 As shown, the slider 91 is provided with recessed portions 95A to 95C corresponding to the plurality of optical elements 50A to 50C, respectively. The frame 94 is provided with a protrusion 96. When the optical element 50A is positioned in the optical path of the light beam A, the recessed portion 95A and the protrusion 96 face each other. Similarly, when the optical element 50B is positioned in the optical path of the light beam A, the recessed portion 95B and the protrusion 96 face each other, and when the optical element 50C is positioned in the optical path of the light beam A, the recessed portion 95C and the protrusion 96 face each other.

[0076] Optical element 50A is an example of a first optical element, and recess 95A is an example of a first recess. Similarly, optical element 50B is an example of a second optical element, and recess 95B is an example of a second recess. Slider 91 and / or frame 94 are formed of a flexible resin material. When optical elements 50A to 50C positioned on the optical path of light beam A are switched, slider 91 and / or frame 94 deforms. The force exerted by the deformed slider 91 and / or frame 94 to restore itself causes any of recesses 95A to 95C that are opposed to projection 96 to engage with projection 96.

[0077] For example, when switching the optical element positioned on the optical path of light beam A from optical element 50A to optical element 50B, if slider 91 is moved leftward in first direction Y, slider 91 and / or frame 94 deform, overcoming the force exerted by the deformed slider 91 and / or frame 94 to restore itself, thereby releasing the engagement between recess 95A and protrusion 96. When slider 91 is further moved leftward, recess 95B faces protrusion 96, and the force exerted by the deformed slider 91 and / or frame 94 to restore itself causes recess 95B to engage with protrusion 96. Slider 91 and / or frame 94 are examples of a force-applying member that applies force to protrusion 96 toward the recess (in the illustrated example, recess 95B) that faces protrusion 96.

[0078] When the shape of the light spot S is set to a normal type in a state where the optical element 50B is arranged on the optical path of the light beam A, if the optical element arranged on the optical path of the light beam A is switched from the optical element 50B to the optical element 50A having a plate thickness larger than that of the optical element 50B, the light beam A can be converged to reduce the size of the light spot S. Figure 11A This is a plan view showing an example of a pictogram 97A indicating that the shape of light spot S is a focused type, and an example of a pictogram 97B indicating that the shape of light spot S is a normal type. By switching the optical element arranged in the optical path of light beam A from optical element 50B to optical element 50C, which has a smaller thickness than optical element 50B, light beam A can be diffused, thereby increasing the size of light spot S. Figure 11B 1 is a top view showing an example of a pictogram 97C indicating that the shape of the light spot S is a diffusion type and an example of a pictogram 97B indicating that the shape of the light spot S is a normal type. Figure 11A In the example shown, the current position of the adjuster 92 is indicated by a mountain-shaped mark, the selectable position of the adjuster 92 is indicated by a dot mark, and the moving path of the adjuster 92 is indicated by an arc mark. The operator can easily and intuitively understand that when the adjuster 92 is rotated clockwise, the shape of the light spot S becomes a focusing type, and when the adjuster 92 is rotated counterclockwise, the shape of the light spot S becomes a normal type. In the example shown in the figure, when the position of the adjuster 92 is in the middle position among the three possible positions, the type of the light spot S is not indicated by the pictogram, but it becomes a slightly focusing type that is different from both the focusing type and the normal type and is equivalent to an intermediate state between the two. In addition, the markings of the current position, selectable position, and moving path of the adjuster 92 are not limited to the example shown in the figure. In addition, Figure 11B The example shown is also related to Figure 11A The examples shown are the same, so duplicate descriptions are omitted.

[0079] According to the optical sensor 1 of the second embodiment, constructed as described above, the multiple optical elements 50A to 50C are linearly moved by the direct-acting mechanism 93 rather than by a rotation mechanism. Therefore, the optical axis of the light beam A is not parallel to the rotation axis of the adjuster 92. The adjuster 92, located on the top surface 105, can be operated while visually checking the optical axis. Furthermore, compared to conventional techniques that shift a projecting lens or rotate a rotating disk, the optical sensor 1 can be more easily miniaturized. Consequently, a compact optical sensor 1 with excellent operability can be provided.

[0080] The embodiments described above are merely for ease of understanding of the present invention and are not intended to limit the present invention. The various elements and their configurations, materials, conditions, shapes, and dimensions of the embodiments are not limited to those illustrated and may be modified as appropriate. In addition, the structures shown in different embodiments may be partially replaced or combined with each other.

[0081] [Note 1]

[0082] A light sensor (1) comprising:

[0083] a light source (5) emitting a Gaussian beam (A) and at least one distribution-changing element (10),

[0084] The at least one distribution changing element (10) is configured to change a Gaussian light beam (A) emitted from the light source (5) into a light beam (B) having a light intensity distribution other than a Gaussian distribution.

[0085] [Note 2]

[0086] A light sensor (1) comprising:

[0087] light source; and

[0088] A light spot variable mechanism (9) is configured to switch the shape of the light spot of the light beam (A) emitted from the light source (5) by switching optical elements (50A to 50C) arranged on the light path of the light beam (A).

[0089] The variable light spot mechanism (9) has:

[0090] a plurality of optical elements (50A to 50C) arranged in a straight line along a first direction (Y) intersecting the direction (X) of travel of the light beam (A); and

[0091] A linear motion mechanism (93) is provided for enabling the plurality of optical elements (50A to 50C) to reciprocate linearly along the first direction (Y).

[0092] Description of labels

[0093] 1: Light sensor; 2: Light projecting unit; 3: Light receiving unit; 4: Circuit board; 5: Light source; 6: Collimator; 7: Light projecting lens; 8: Display; 9: Switching mechanism (light spot variable mechanism); 10: Distribution changing element; 10A to 10C: 1st to 3rd distribution changing elements; 20: Microlens array; 21: Spherical lens; 22: Cylindrical lens; 30: Diffraction optical element; 31: Concave portion; 32: Convex portion; 40: Multi-stage lens; 41: Concave lens; 42: Convex lens; 50A to 50C: Optical element; 91: Slider (an example of a force-applying member); 92: adjuster; 93: direct-acting mechanism; 93P: pinion; 93R: rack; 94: frame (an example of a force-applying member); 95A to 95C: recessed portion; 96: convex portion; 97A to 97C: pictogram; 100: housing; 101: front surface; 102: back surface; 105: top surface; 106: bottom surface; A: Gaussian-type light beam (Gaussian beam); B: light beam other than Gaussian-type; S: light spot; W: workpiece; X: direction of travel of the light beam; Y: first direction; Z: second direction.

Claims

1. A light sensor, comprising a light source for emitting a Gaussian beam and at least one distribution changing element, wherein: Each of the at least one distribution changing elements is configured to change a Gaussian beam emitted from the light source into a beam having a light intensity distribution other than a Gaussian distribution.

2. The optical sensor according to claim 1, wherein The at least one distribution changing element is a plurality of distribution changing elements including a first distribution changing element and a second distribution changing element, This optical sensor is configured to be able to switch the first distribution changing element and the second distribution changing element to switch the shape of the spot of a light beam having a light intensity distribution other than a Gaussian one.

3. The light sensor according to claim 1, wherein Each of the at least one distribution changing elements is configured to change a Gaussian beam emitted from the light source into a beam having a flat-top light intensity distribution.

4. The light sensor according to claim 1, wherein Each of the at least one distribution changing elements is configured to change the Gaussian beam emitted from the light source into a beam with a light intensity distribution in which the light intensity at the peripheral portion of the light spot is higher than that at the central portion.

5. The light sensor according to claim 1, wherein The optical sensor further includes a collimator that collimates the Gaussian beam emitted from the light source and causes the collimated beam to enter the at least one distribution changing element. The light sensor according to claim 1 , wherein: The optical sensor is a TOF sensor, or time-of-flight sensor, which measures distance based on the time it takes for a light beam projected at a fixed period to be reflected by a workpiece and return.

7. The light sensor according to claim 1, wherein The distribution changing element is a microlens array including a plurality of spherical lenses or a plurality of cylindrical lenses, and is configured to change Gaussian beams emitted from the light source and passing through each of the plurality of spherical lenses or each of the plurality of cylindrical lenses into beams having a light intensity distribution other than a Gaussian type by overlapping with each other.

8. The light sensor according to claim 1, wherein The distribution changing element is a diffractive optical element configured to diffuse the Gaussian beam emitted from the light source and change the beam into a beam having a light intensity distribution other than a Gaussian beam.

9. The light sensor according to claim 1, wherein The distribution changing element is a multi-stage lens including at least one concave lens and at least one convex lens, configured to cause the Gaussian light beam emitted from the light source to diverge through the at least one concave lens and converge through the at least one convex lens to change into a light beam with a light intensity distribution other than the Gaussian type.

10. The light sensor according to claim 9, wherein A part or all of the convex lens is composed of a liquid lens.

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