Optical detection unit, measurement device, and sorter

Abstract

An optical detection unit of an optical measurement device comprises: an optical sensor configured to optically detect an object; a mirror configured to bend an optical path in order to guide light to the optical sensor; and a frame body that has a bottomless cylinder shape having two opposing openings, the frame body accommodating at least the mirror.

Description

Optical detection units, measuring devices and sorting machines

[0001] The present disclosure relates to an optical detection unit used in optical measurement devices, optical sorting machines, and the like.

[0002] Optical sorting machines (hereinafter simply referred to as sorters) that identify and remove foreign objects and defective products contained in sorting objects (hereinafter simply referred to as objects) transported along a transport path using optical information obtained by an optical sensor when a light source irradiates the objects (hereinafter simply referred to as objects) have been known for some time (see, for example, Japanese Patent Application Laid-Open Nos. 10-174938 and 11-621). This type of sorting machine sometimes uses an optical detection unit in which an optical sensor and a mirror positioned to bend the optical path from the object detection position to the optical sensor are arranged within the same frame. With such an optical detection unit, bending the optical path with the mirror ensures a long optical path while minimizing the size of the frame. Furthermore, during the manufacture of the sorting machine, attaching a prefabricated optical detection unit to the sorter eliminates the need to individually position the optical sensor and mirror relative to the sorter, making manufacturing easier.

[0003] However, conventional sorters leave room for improvement in terms of their optical detection units. For example, conventional sorters leave room for improvement in the versatility of their optical detection units in manufacturing. Specifically, the frame of the optical detection unit of a conventional sorter is manufactured by die-casting or injection molding. Therefore, in order for sorter manufacturers to manufacture and sell sorters with various processing capacities, they must individually manufacture frame sizes corresponding to the processing capacities. This is because the processing capacity depends on the width of the object in a direction perpendicular to the transport direction, and multiple die-cast molds with different widths must be individually manufactured to accommodate different processing capacities. Furthermore, the manufacturing costs of die-casting or injection-molding molds are high, leaving room for improvement in manufacturing costs. For these reasons, improvements to conventional optical detection units are desirable. This is true not only for the optical detection units of sorters, but also for the optical detection units of optical measurement devices for optically measuring the condition of objects.

[0004] The present disclosure has been made to solve at least part of the above-mentioned problems, and can be realized, for example, in the following forms.

[0005] According to a first aspect of the present disclosure, there is provided an optical detection unit for an optical measurement device, the optical detection unit including: an optical sensor configured to optically detect an object; a mirror configured to bend an optical path to guide light to the optical sensor; and a frame having an open-bottom cylindrical shape with two opposing openings and accommodating at least the mirror.

[0006] In this specification, "for optical measuring devices" includes applications to optical measuring devices that do not have a sorting function and applications to optical sorters that include optical measuring devices. Also, in this specification, "light" refers to various electromagnetic waves. "Light" includes, for example, visible light, near-infrared light, and X-rays.

[0007] According to this optical detection unit, the frame has a bottomless cylindrical shape, i.e., a hollow shape, making it lighter than conventional frames manufactured by die casting or injection molding. Furthermore, because the frame has a bottomless cylindrical shape, during the manufacturing stage of the optical detection unit, the frame can be cut at a desired position in its longitudinal direction (i.e., in a direction perpendicular to the two opposing openings) to obtain a shorter frame. Alternatively, multiple frames can be joined in the longitudinal direction to obtain a longer frame. In this way, a frame whose longitudinal length has been adjusted to a desired length can be used for multiple optical measuring devices or optical sorting machines with various processing capacities. In other words, the frame can be commonly used for multiple optical detection units used in multiple optical measuring devices or optical sorting machines with different processing capacities. Therefore, the manufacturing costs of multiple optical measuring devices or optical sorting machines with various processing capacities can be reduced. Furthermore, a bottomless cylindrical frame can also be manufactured by extrusion molding. In this case, the manufacturing costs of the frame can be significantly reduced compared to manufacturing by die casting or injection molding.

[0008] According to a second aspect of the present disclosure, there is provided an optical detection unit for an optical measurement device. The optical measurement device includes a first unit and a second unit. Each of the first unit and the second unit includes a frame body having a bottomless cylindrical shape with two openings facing each other in a first direction, an optical sensor housed in or attached to the frame body and configured to optically detect an object, and a mirror housed in the frame body and configured to bend an optical path to guide light to the optical sensor. The optical detection unit further includes a connecting member that fixedly connects the first frame body, which is the frame body of the first unit, and the second frame body, which is the frame body of the second unit, in a state where they are aligned in a second direction perpendicular to the first direction.

[0009] According to this optical detection unit, the first frame and the second frame each have a bottomless cylindrical shape, so that the same effect as in the first embodiment can be obtained. Furthermore, because the first frame and the second frame are fixedly connected by a connecting member, the relative positions of the first frame and the second frame can be determined in advance. Therefore, there is no need to adjust the relative positions of the first frame and the second frame when assembling the optical detection unit to an optical measuring device or an optical sorting machine during the manufacturing stage, and manufacturing can be facilitated.

[0010] According to a third aspect of the present disclosure, in the second aspect, each of the first unit and the second unit includes a transition member spanning two opposing inner surfaces of the frame. The mirror is attached directly or indirectly to the transition member. This aspect makes it easy to install the mirror at a desired position and orientation (i.e., installation angle).

[0011] According to a fourth aspect of the present disclosure, in the third aspect, the transition member has a cylindrical shape at least at a portion where the mirror is attached. With this aspect, the rigidity of the transition member at the portion where the mirror is attached is increased, allowing the mirror to be accurately positioned in a desired position and orientation.

[0012] According to a fifth aspect of the present disclosure, in any of the second to fourth aspects, the connecting member includes a first-side connecting member that connects the first frame body and the second frame body while closing a first opening of the two opposing openings of the first frame body and a first opening of the two opposing openings of the second frame body, and a second-side connecting member that connects the first frame body and the second frame body while closing a second opening of the two opposing openings of the first frame body opposite the first opening and a second opening of the two opposing openings of the second frame body. According to this aspect, the first frame body and the second frame body can be connected using members for closing the openings of the first and second frame bodies. Therefore, the number of parts can be reduced.

[0013] According to a sixth aspect of the present disclosure, in any of the third, fourth, and fifth aspects including the third aspect, the transition member includes a positioning portion extending toward the connecting member. The connecting member includes a positioning hole into which the positioning portion is inserted. According to this aspect, by inserting the positioning portions into the positioning holes, the relative positions of the connecting member (and therefore the first and second frame bodies) and the transition member on a plane perpendicular to the first direction are fixed. This suppresses distortion of the transition member, improving the accuracy of the position and orientation of the mirror.

[0014] According to a seventh aspect of the present disclosure, in the third aspect, the fourth aspect, the fifth aspect including the third aspect, or the sixth aspect, the transition member has a finished surface for mounting the mirror. According to this aspect, the dimensional accuracy of the surface for mounting the mirror can be improved, and the accuracy of the position and orientation of the mirror can be ensured satisfactorily.

[0015] According to an eighth aspect of the present disclosure, in the third, fourth, fifth, sixth, or seventh aspects, the transition member includes at least one of an inclined portion angled with respect to a direction perpendicular to the two opposing faces of the frame and a raised portion raised above a base of the transition member. The mirror is disposed on at least one of the inclined portion and the raised portion. This aspect makes it easy to position the mirror in a desired position and orientation.

[0016] According to a ninth aspect of the present disclosure, in the third aspect, the fourth aspect, the fifth aspect including the third aspect, and any of the sixth to eighth aspects, the optical detection unit includes a pair of holding members attached to the transition member and spaced apart in the first direction, and holding the mirror. Each of the pair of holding members includes a positioning surface and a biasing member that biases the mirror toward the positioning surface so that the mirror abuts against the positioning surface. According to this aspect, the mirror is pressed against the positioning surfaces of the pair of holding members, thereby ensuring good accuracy in the position and orientation of the mirror relative to the positioning surfaces. Moreover, while a structure that holds the mirror over its entire extension distance in the first direction requires high manufacturing precision, this aspect does not require such a structure, making it easy to manufacture.

[0017] According to a tenth aspect of the present disclosure, in any of the second to ninth aspects, the first frame body and the second frame body are each an extrusion molded product. This aspect allows for reduced manufacturing costs compared to when these components are formed by die casting or injection molding.

[0018] According to an eleventh aspect of the present disclosure, in the tenth aspect, each of the first frame body and the second frame body is formed by assembling a plurality of members. According to this aspect, the frame body can be manufactured using a smaller-scale extrusion molding device than when the first frame body and the second frame body are integrally molded. Furthermore, by replacing the transition member, the position and orientation of the mirror can be changed, thereby changing the optical path length. In other words, even when the optical path length needs to be changed, the first frame body and the second frame body can be reused as they are.

[0019] According to a twelfth aspect of the present disclosure, in any of the second to eleventh aspects, the optical detection unit includes: a first light source configured to irradiate light toward a detection position of an object by the optical sensor and housed in a first frame; a second light source configured to irradiate light toward a detection position of an object by the optical sensor and housed in a second frame; a first background disposed within or on the first frame to form a background of a field of view of a second optical sensor that is an optical sensor of the second unit but outside the field of view of the first optical sensor that is an optical sensor of the first unit; and a second background disposed within or on the second frame to form a background of a field of view of the first optical sensor but outside the field of view of the second optical sensor. The first background is located closer to the second frame than the first light source, and the second background is located closer to the first frame than the second light source. According to this embodiment, the sizes of the first frame body and the second frame body in the second direction can be made more compact than in conventional optical detection units in which the first background is located farther from the second frame body (in other words, the detection position of the object) than the first light source, and the second background is located farther from the first frame body (in other words, the detection position of the object) than the second light source.

[0020] Furthermore, the optical path of the light detected by the first optical sensor extends in a diverging manner in the first direction as viewed from the first optical sensor, not only between the first optical sensor and the object detection position, but also between the object detection position and the second background beyond the object detection position. Therefore, the greater the distance between the second background and the first optical sensor (in other words, the first frame), the greater the width of the second background, and therefore the second frame, in the first direction. However, according to this embodiment, since the second background is positioned closer to the first optical sensor than in conventional optical detection units, the distance over which the optical path extends in a diverging manner to the second background can be shortened (i.e., the width in the first direction can be reduced). As a result, the size of the second frame in the first direction can be made more compact. For the same reason, the size of the first frame in the first direction can also be made more compact.

[0021] According to a thirteenth aspect of the present disclosure, in the twelfth aspect, each of the first unit and the second unit is attached to the frame body so that light detected by the optical sensor can pass through, and includes a transparent member that separates the inside and outside of the frame body. The first background and the second background are located on the transparent members of the first unit and the second unit, respectively. According to this aspect, the distance between the second background and the first optical sensor can be made smaller, thereby making the size of the second frame body in the first direction more compact. Also, for the same reason, the size of the first frame body in the first direction can be made more compact.

[0022] According to a fourteenth aspect of the present disclosure, in the thirteenth aspect, the first background is located within the first frame body, and the second background is located within the second frame body. According to this aspect, even if the first background and the second background are unintentionally separated from the transparent member, the first background and the second background will not be mixed into the object as foreign matter.

[0023] According to a fifteenth aspect of the present disclosure, in any of the twelfth to fourteenth aspects, each of the first light source and the second light source includes an LED as a light-emitting element. Since LEDs have relatively high directivity, this aspect makes it easy to set a layout in which light irradiated from the first light source and the second light source toward the detection position of the object is not blocked by the first background and the second background.

[0024] According to a sixteenth aspect of the present disclosure, there is provided an optical detection unit for an optical measurement device. This optical detection unit comprises a first frame body and a second frame body arranged opposite each other, a first optical sensor housed in the first frame body or attached to the first frame body and configured to optically detect an object, a second optical sensor housed in the second frame body or attached to the second frame body and configured to optically detect an object, a first light source housed in the first frame body and configured to irradiate light toward a position at which the object is detected by the first optical sensor, a second light source housed in the second frame body and configured to irradiate light toward a position at which the object is detected by the second optical sensor, a first background located in the first frame body or on the first frame body and in a position that forms the background of the field of view of the second optical sensor but is outside the field of view of the first optical sensor, and a second background located in the second frame body or on the second frame body and in a position that forms the background of the field of view of the first optical sensor but is outside the field of view of the second optical sensor. The first background is located closer to the second frame body than the first light source, and the second background is located closer to the first frame body than the second light source. This embodiment provides the same effect as the twelfth embodiment. The sixteenth embodiment may be combined with any of the thirteenth to fifteenth embodiments.

[0025] FIG. 1 is a schematic diagram showing a general configuration of a sorting machine according to an embodiment; FIG. 2 is a perspective view of an optical detection unit; FIG. 3 is a cross-sectional view of the optical detection unit; FIG. 4 is a perspective view of the rear side of the optical detection unit, with the connecting member removed; FIG. 5 is an exploded view of a frame and a transition member; FIG. 6 is a perspective view of the optical detection unit, with the connecting member shown in perspective; FIG. 7 is a perspective view showing the internal structure of the optical detection unit; and FIG. 8 is a partial cross-sectional view showing a configuration in which a mirror is held by a holding member.

[0026] First, referring to FIG. 1 , a schematic configuration of an optical sorting machine (hereinafter simply referred to as a sorting machine) 10 according to one embodiment will be described. FIG. 1 is a schematic diagram showing the schematic configuration of the sorting machine 10. In this embodiment, the sorting machine 10 is used to sort foreign matter and defective products (immature grains, discolored grains, foreign matter (e.g., pebbles, mud, glass fragments, etc.)) from rice grains, which are an example of a sorting target object (hereinafter simply referred to as a target object) 11. However, the target object 11 is not limited to rice grains and may be any solid object. For example, the target object 11 may be unhulled rice, wheat grains, sesame seeds, beans (soybeans, chickpeas, edamame beans, coffee beans, etc.), resin material, crushed plastic, rubber fragments, etc.

[0027] The sorting machine 10 includes a storage tank 21, a feeder 22, a chute 23, a non-defective product discharge gutter 24, a defective product discharge gutter 25, a sorting section 26, an optical detection unit 20, and a controller 15. The controller 15 controls the overall operation of the sorting machine 10. In this embodiment, the controller 15 includes a CPU (processor) and memory, and realizes various functions by executing predetermined programs stored in the memory. However, the functions of the controller 15 may be realized by a dedicated circuit, or by a combination of a CPU and a dedicated circuit.

[0028] The storage tank 21 temporarily stores the objects 11. The feeder 22 supplies the objects 11 stored in the storage tank 21 onto a chute 23, which serves as an example of an object transfer means. The objects 11 supplied onto the chute 23 slide downward on the chute 23 and fall from the bottom end of the chute 23. The objects 11 released into the air from the bottom end of the chute 23 fall generally in the inclined direction of the chute 23 (are transported through the air). The direction in which the objects 11 fall at this time is also referred to as a transfer direction D3 of the objects 11. The chute 23 has a predetermined width in a first direction D1 (see FIG. 2 ) that allows multiple objects 11 to fall simultaneously. The first direction D1 is parallel to the sliding surface of the chute 23 and perpendicular to the transfer direction D3.

[0029] The optical detection unit 20 irradiates light onto the object 11 that has slid down the chute 23 (i.e., the object 11 falling from the chute 23) and detects light associated with the object 11 (specifically, transmitted light that has passed through the object 11 and / or reflected light that has been reflected by the object 11). The optical detection unit 20 includes a first unit 20a and a second unit 20b. The first unit 20a is disposed on one side (also referred to as the front side) of the transfer path (in other words, the falling trajectory) of the object 11. On the other hand, the second unit 20b is disposed on the other side (also referred to as the rear side) of the transfer path of the object 11.

[0030] The first unit 20a and the second unit 20b are disposed symmetrically with respect to the transfer path of the object 11 and have the same configuration. Specifically, the first unit 20a includes a first light source 30a and a first optical sensor 60a, and the second unit 20b includes a second light source 30b and a second optical sensor 60b.

[0031] In this embodiment, the first light source 30a and the second light source 30b are each a light source unit for irradiating the object 11 being transported on the transport path with visible light. The first light source 30a and the second light source 30b emit a first light 31a and a second light 31b, respectively. The light 31a and 31b each have a wavelength corresponding to red, a wavelength corresponding to green, and a wavelength corresponding to blue. In this embodiment, each of the light sources 30a and 30b includes a so-called color LED.

[0032] The first optical sensor 60a and the second optical sensor 60b detect light emitted from the first light source 30a and the second light source 30b and associated with the object 11 located at a detection position 14. The detection position 14 is a position on the transfer path of the object 11 where the optical sensors 60a and 60b optically detect the object 11. Specifically, the front-side first optical sensor 60a can detect a first light 31a emitted from the front-side first light source 30a and reflected by the object 11, and a second light 31b emitted from the rear-side second light source 30b and transmitted through the object 11. The rear-side second optical sensor 60b can detect a second light 31b emitted from the rear-side second light source 30b and reflected by the object 11, and a first light 31a emitted from the front-side first light source 30a and transmitted through the object 11.

[0033] In this embodiment, each of the first optical sensor 60a and the second optical sensor 60b is a line sensor having a plurality of light-receiving elements linearly arranged in the first direction D1 (the width direction of the chute 23). However, each of the optical sensors 60a and 60b may also be an area sensor. Also, in this embodiment, each of the optical sensors 60a and 60b is a color CCD sensor capable of individually detecting red light, green light, and blue light. However, the optical sensors 60a and 60b may also be other types of sensors, such as a color CMOS sensor.

[0034] The first unit 20a further includes a first frame 40a, a first transparent member 48a, and a first background 75a. Similarly, the second unit 20b further includes a second frame 40b, a second transparent member 48b, and a second background 75b. The first frame 40a houses or has attached thereto a first light source 30a and a first optical sensor 60a. The second frame 40b houses or has attached thereto a second light source 30b and a second optical sensor 60b.

[0035] The first transparent member 48a is attached to the front-side first frame body 40a so as to be able to transmit light detected by the first optical sensor 60a. The second transparent member 48b is attached to the rear-side second frame body 40b so as to be able to transmit light detected by the second optical sensor 60b. The first transparent member 48a separates the inside and outside of the first frame body 40a (i.e., the transfer path of the object 11). The second transparent member 48b separates the inside and outside of the second frame body 40b (i.e., the transfer path of the object 11). The frame bodies 40a, 40b and the transparent members 48a, 48b prevent dust generated along the transfer path of the object 11, or the object 11 itself, from entering the space where the light sources 30a, 30b and the optical sensors 60a, 60b are arranged.

[0036] The first background 75a is disposed within or on the first frame 40a and serves as a background for the field of view of the second optical sensor 60b. The first background 75a is disposed outside the field of view of the first optical sensor 60a. The second background 75b is disposed within or on the second frame 40b and serves as a background for the field of view of the first optical sensor 60a. The second background 75b is disposed outside the field of view of the second optical sensor 60b.

[0037] The outputs from the first optical sensor 60a and the second optical sensor 60b, i.e., analog signals representing the detected light intensities, are amplified by an AC / DC converter (not shown) at a predetermined gain and then converted into digital signals. These digital signals are input to the controller 15 as image data. The controller 15 identifies the state of the object 11 based on the input images. Such identification is performed for each of the objects 11.

[0038] In this embodiment, the state determined by the controller 15 includes at least one of a color state (in other words, an optical state) and a shape and / or a size state. The state also includes at least one of a feature expressed by a physical quantity and a quality determined based on the feature.

[0039] The feature amount of the color state includes the color gradation value of each pixel of the image representing the object 11. The feature amount of the shape and / or size state may include, for example, at least one of the area, height, width, perimeter, and circularity of the whole and / or part of the object 11.

[0040] In this embodiment, "quality" includes, for example, a distinction between good products (i.e., rice grains of relatively high quality) and defective products (i.e., rice grains of relatively low quality and / or foreign objects). However, "quality" may also include the type of defect (e.g., whether it corresponds to broken rice, immature rice, discolored rice, damaged rice, dead rice, or foreign objects). Alternatively, "quality" may include a distinction between objects that should be removed by the sorting unit 26 and objects that should not be removed. Furthermore, "quality" includes quality determined based on the color state and quality determined based on the shape and / or dimensional state. Defective products determined based on the color state may include, for example, immature rice, discolored rice, damaged rice, dead rice, and foreign objects. Defective products determined based on the shape and / or dimensional state may include, for example, broken rice, insect-damaged rice, and foreign objects.

[0041] In this embodiment, the controller 15 determines whether the object 11 is a good or defective product by comparing the color feature (i.e., the gradation value of the image data) with a predetermined threshold (i.e., based on whether the color feature is within a predetermined normal range). Such a determination may be made based on a representative value (e.g., average, median, maximum, minimum, etc.) of the gradation values ​​of multiple pixels constituting the image of the object 11. Alternatively, the defective product may include an object 11 having a partial defect of a predetermined size or larger. Such a partial defect may be determined based on the criterion that the number of pixels constituting the image of the object 11 whose gradation values ​​are outside the normal range is a predetermined number or larger (i.e., the area of ​​the defective portion is a predetermined value or larger).

[0042] Furthermore, in this embodiment, the controller 15 determines whether the object 11 is a good or bad product by comparing the geometric and / or dimensional feature values ​​with predetermined threshold values ​​(in other words, based on whether the geometric and / or dimensional feature values ​​are within a predetermined normal range).

[0043] The sorting unit 26 sorts the objects 11 based on the state determined by the controller 15. This sorting is performed by a trajectory changing operation for changing the trajectory of a specific object 11. Specifically, the sorting unit 26 includes a plurality of jet nozzles 27 arranged in a first direction D1 and a plurality of valves 28. In FIG. 1 , for the sake of simplicity, the number of jet nozzles 27 is shown as being the same as the number of valves 28, but the correspondence between the number of jet nozzles 27 and the number of valves 28 actually depends on the number of openings that the jet nozzles 27 have.

[0044] More specifically, the controller 15 determines the specific object 11 to be subjected to the trajectory change operation based on the determined state, and outputs a control signal to the valve 28 located at the position corresponding to the specific object 11. In this embodiment, the specific object 11 is an object 11 identified as a foreign object or a defective product. In response to the control signal, the valve 28 is opened, and air 29 is sprayed from the corresponding opening of the corresponding spray nozzle 27. The specific object 11 is blown away by the air 29, deviating from its falling trajectory along the transfer direction D3 and being guided to the defective product discharge gutter 25 (shown as object 12 in FIG. 1). On the other hand, the air 29 is not sprayed on objects 11 determined to be non-defective. Therefore, objects 11 determined to be non-defective are guided to the non-defective product discharge gutter 24 without changing their falling trajectory (shown as object 13 in FIG. 1). In this manner, the objects 11 are sorted into non-defective products, foreign objects, and defective products. The specific objects 11 described above may be arbitrarily set. For example, air 29 may be sprayed onto the object 11 that has been identified as a non-defective product (so-called reverse spraying).

[0045] The optical detection unit 20 will be described in detail below with reference to FIGS. 2 to 8. The first unit 20a and the second unit 20b are arranged symmetrically with respect to a plane that passes through the detection position 14 and is perpendicular to the second direction D2, and have the same shape and configuration. Therefore, the following description of the common configuration, functions, and effects will be limited to the first unit 20a and the second unit 20b, and overlapping descriptions of both units will be omitted. In the drawings, corresponding components of the first unit 20a and the second unit 20b are assigned the same numbers, with the suffixes "a" and "b" added, respectively, to distinguish between the two components. Furthermore, the components of the first unit 20a and the second unit 20b are assigned names that include "first" and "second," respectively.

[0046] As shown in Figures 6 and 7, the first frame 40a has a bottomless cylindrical shape with two first openings 41a facing each other in the first direction D1 (only one of the first openings 41a is visible in the figure). Therefore, the cross section of the first frame 40a perpendicular to the first direction D1 is the same at any position in the first direction D1. The term "cylindrical" includes a shape in which the outer diameter of the first frame 40a is completely closed and a shape in which the outer diameter is partially open in the cross section perpendicular to the first direction D1. The term "cylindrical" also includes a shape in which no partition is formed inside and a shape in which a partition is formed inside.

[0047] 3, 6, and 7, the first frame 40a and the second frame 40b are opposed to each other (side by side) in the second direction D2, which is perpendicular to the first direction D1 (the width direction of the chute 23) and the transport direction D3.

[0048] In this embodiment, the first frame 40a is formed by assembling multiple members. Specifically, the first frame 40a is formed by assembling a first member 42a, a second member 43a, a third member 44a, a fourth member 45a, and a fifth member 46a shown in FIG. 5 . For example, as shown in FIG. 3 , the first member 42a forms the outer side (the side farther from the detection position 14) of the first frame 40a. The fourth member 45a forms the inner top surface and inner upper side surface of the first frame 40a. The third member 44a has a substantially C-shaped cross section and forms the inner lower portion of the first frame 40a. The fifth member 46a forms the lower surface and outer lower side surface of the first frame 40a. The second member 43a functions as a partition inside the first frame 40a.

[0049] The internal configuration of the first frame 40a will be described below. As shown in Fig. 3, the first light source 30a and the first background light source 34a are housed in the space inside and below the first frame 40a (the space inside the third member 44a). A first transparent member 48a is attached to the open portion of the third member 44a. As shown in Fig. 6, the side (opening) of the space inside and below the first frame 40a is closed by a first side plate 35a.

[0050] The first light source 30a includes a first upper light source 32a and a first lower light source 33a. The first upper light source 32a and the first lower light source 33a irradiate the detection position 14 with first light 31a from above and below, respectively, through the first transparent member 48a. The first background light source 34a irradiates light toward the first background 75a. The first background 75a and the first background light source 34a are positioned between the first upper light source 32a and the first lower light source 33a in the up-down direction. The first background 75a is positioned closer to the detection position 14 (in other words, closer to the second frame 40b) than the first upper light source 32a and the first lower light source 33a.

[0051] In this embodiment, the first background 75a is disposed within the first frame 40a. The first background 75a is attached to the inner surface of the first transparent member 48a. The first background 75a is formed from a material having light diffusibility. In this embodiment, the first background 75a is in the form of a sticker and is attached to the first transparent member 48a. This makes it possible to easily attach the first background 75a to the first transparent member 48a. Because the first background 75a is disposed within the first frame 40a, the first background 75a will not peel off and become mixed into the object 11 being transported on the transport path.

[0052] The first background 75a may have any form, for example, a resin plate. Alternatively, the first background 75a may be a printed matter printed on the first transparent member 48a or any other member. Furthermore, the first background 75a may be attached to the outer surface of the first transparent member 48a. Alternatively, the first background 75a may be disposed at any position closer to the detection position 14 (in other words, the second frame body 40b) than the first upper light source 32a and the first lower light source 33a.

[0053] As shown in Figures 3 and 6, a first upper transition member 50a and a first lower transition member 51a are respectively bridged between the inner surfaces of the opposing first member 42a and second member 43a. As shown in Figure 5, in this embodiment, the first upper transition member 50a and the first lower transition member 51a have an overall cylindrical shape. The upper surface of the first upper transition member 50a is exposed from the first frame body 40a and also functions as part of the first frame body 40a.

[0054] As shown in FIG. 3 , a first optical sensor 60a is attached to the upper surface of the first upper transition member 50a. Specifically, a first cylindrical portion 62a is attached coaxially around a through hole in the upper surface of the first upper transition member 50a, and a rectangular box-shaped first sensor housing portion 61a is attached above the first cylindrical portion 62a. The first optical sensor 60a is housed within the first sensor housing portion 61a. By exposing the operating member of the focus adjustment mechanism of the first optical sensor 60a from the first cylindrical portion 62a, the user can adjust the focus of the first optical sensor 60a without disassembling the first frame body 40a. However, the first optical sensor 60a may be attached to the first frame body 40a without the first cylindrical portion 62a, or may be housed within the first frame body 40a.

[0055] 3, within the first frame 40a, first mirrors 71a, 72a, and 73a are attached to the first upper transition member 50a and the first lower transition member 51a via first holding members 81a, 82a, and 83a. The first mirrors 71a, 72a, and 73a are installed to bend the optical path of a first optical axis 63a extending from the detection position 14 to the first optical sensor 60a. As viewed from the detection position 14, the first optical axis 63a passes through the through holes of the first transparent member 48a, the third member 44a, and the fourth member 45a, is bent three times by the first mirrors 71a, 72a, and 73a, and then passes through the through hole of the first upper transition member 50a, the interior of the first cylindrical portion 62a, and the through hole of the first sensor accommodating portion 61a to reach the first optical sensor 60a. The first mirrors 71 a, 72 a, and 73 a can ensure a long optical path length of the first optical axis 63 a while preventing the first frame 40 a from becoming large. The number of first mirrors may be any number equal to or greater than one.

[0056] As shown in Fig. 3, the first mirror 71a is attached to the underside of the first upper transition member 50a via a pair of first holding members 81a (only one of the first holding members 81a is visible in Fig. 3). The underside of the first upper transition member 50a is angled with respect to a direction perpendicular to the inner surfaces of the opposing first member 42a and second member 43a (i.e., the second direction D2).

[0057] As shown in FIG. 3 , the first mirrors 72a and 73a are attached to the first lower transition member 51a via a pair of first holding members 82a and a pair of first holding members 83a (only one of the first holding members 82a and 83a is visible in FIG. 3 ). Specifically, the first lower transition member 51a includes a first inclined portion 52a and a first raised portion 53a. The first inclined portion 52a is angled relative to a direction perpendicular to the inner surfaces of the opposing first and second members 42a and 43a (i.e., the second direction D2). The first raised portion 53a is a portion raised higher than the base of the first lower transition member 51a (i.e., the connecting portion with the first and second members 42a and 43a). A first mirror 72a is attached to the first inclined portion 52a via a pair of first holding members 82a. A first mirror 73a is attached to the first raised portion 53a via a pair of first holding members 83a.

[0058] The configuration in which the first mirrors 71 a, 72 a, 73 a are attached to the first upper transition member 50 a or the first lower transition member 51 a makes it easier to install the first mirrors 71 a, 72 a, 73 a in the desired positions and orientations than the configuration in which the first mirrors 71 a, 72 a, 73 a are attached to the first frame 40 a. Furthermore, the configuration in which the first mirrors 71 a, 72 a, 73 a are attached to the underside of the first upper transition member 50 a, the first inclined portion 52 a, and the first raised portion 53 a, which are angled with respect to the second direction D2, makes it easier to position the first mirrors 71 a, 72 a, 73 a in the desired positions and orientations. Furthermore, since the first upper transfer member 50a and the first lower transfer member 51a to which the first mirrors 71a, 72a, 73a are attached have a cylindrical shape, the rigidity of the first upper transfer member 50a and the first lower transfer member 51a is high and the first mirrors 71a, 72a, 73a can be accurately positioned in the desired positions and orientations. The first upper transfer member 50a and the first lower transfer member 51a may have a cylindrical shape only at the locations where the first mirrors 71a, 72a, 73a are attached.

[0059] 7, the first mirror 72a extends in the first direction D1 across the entire field of view of the first optical sensor 60a. The pair of first holding members 82a are spaced apart in the first direction D1 and arranged on the first lower transition member 51a (more specifically, the first raising portion 53a), and hold both ends of the first mirror 72a in the longitudinal direction.

[0060] As shown in FIG. 8 , the first holding member 82a includes a first member 181a and a second member 182a. The first member 181a and the second member 182a include recesses facing each other. These recesses are closed on the outside in the first direction D1 and open on the inside. Both ends of the first mirror 72a in the first direction D1 are accommodated in the recesses of the pair of second members 182a, and the pair of first members 181a are screwed to the pair of second members 182a, respectively, so that both ends of the first mirror 72a are held by the first holding member 82a.

[0061] As shown in FIG. 8 , the first member 181a has a flat first positioning surface 183a on its inner surface. The first positioning surface 183a is an inner surface facing the second member 182a. A first biasing member 90a is disposed between the inner surface of the second member 182a and the first mirror 72a. In this embodiment, the first biasing member 90a is in the form of a mountain-shaped leaf spring. The first biasing member 90a biases the first mirror 72a toward the first positioning surface 183a so that the first mirror 72a abuts against the first positioning surface 183a.

[0062] According to this holding configuration for the first mirror 72a, the pair of first holding members 82a holds only both ends of the first mirror 72a, eliminating the need for a structure that precisely holds the first mirror 72a over the entire extension distance in the first direction D1. This allows the first unit 20a to be easily manufactured while ensuring accurate position and orientation of the first mirror 72a. Furthermore, because the first mirror 72a is pressed against the pair of first positioning surfaces 183a, accurate position and orientation of the first mirror 72a can be ensured using the first positioning surfaces 183a as references. Although not shown, the first mirrors 71a and 73a are also held in a similar manner by the pair of first holding members 81a and the pair of first holding members 83a, respectively.

[0063] In this embodiment, the surfaces of the transition members 50a, 51a on which the first mirrors 71a, 72a, 73a are attached (more specifically, the lower surface of the first upper transition member 50a and the upper surfaces of the first inclined portion 52a and the first raised portion 53a) are finished. This improves the dimensional accuracy of the surfaces on which the first mirrors 71a, 72a, 73a are attached, thereby ensuring better accuracy in the position and orientation of the first mirrors 71a, 72a, 73a.

[0064] As shown in FIGS. 2 and 6 , the optical detection unit 20 further includes a first-side connecting member 100 and a second-side connecting member 110. Each of the connecting members 100 and 110 has the form of a substantially rectangular plate. Each of the connecting members 100 and 110 fixedly connects the first frame body 40a and the second frame body 40b while the first frame body 40a and the second frame body 40b are aligned in the second direction D2. This configuration allows the relative positions of the first frame body 40a and the second frame body 40b to be determined in advance. Therefore, there is no need to adjust the relative positions of the first frame body 40a and the second frame body 40b when assembling the optical detection unit 20 to the sorting machine 10 during manufacturing, facilitating manufacturing.

[0065] Specifically, the first-side connecting member 100 connects the first frame body 40a and the second frame body 40b while closing one of the two opposing first openings 41a (hereinafter also referred to as the first side) of the first frame body 40a and the second opening 41b on the first side of the two opposing second openings 41b of the second frame body 40b. The second-side connecting member 110 connects the first frame body 40a and the second frame body 40b while closing the first opening 41a on the second side opposite to the first side of the two opposing first openings 41a of the first frame body 40a and the second opening 41b on the second side of the two opposing second openings 41b of the second frame body 40b.

[0066] More specifically, as shown in FIG. 5 , a C-shaped connecting hole 47a is formed in each of the first member 42a, second member 43a, third member 44a, fourth member 45a, and fifth member 46a that constitute the first frame body 40a. Also, as shown in FIG. 2 , the first-side connecting member 100 is formed with a plurality of fastening through holes 102 at positions corresponding to the connecting holes 47a. The first frame body 40a and the first-side connecting member 100 are integrated by inserting and tightening bolts 103 (see FIG. 6 ) into the fastening through holes 102 and the connecting holes 47a. Note that FIG. 2 shows the bolts 103 inserted into only some of the fastening through holes 102. Although not shown, the first frame body 40a and the second-side connecting member 110 are integrated in the same manner as the first-side connecting member 100.

[0067] Similarly, as shown in Fig. 5, each of the first upper transition member 50a and the first lower transition member 51a has a C-shaped connecting hole 57a formed therein. Furthermore, as shown in Fig. 2, the first side connecting member 100 has a plurality of fixing through holes 102 formed at positions corresponding to the connecting holes 57a. By inserting and tightening bolts 103 (see Fig. 6) into the fixing through holes 102 and the connecting holes 57a, the positional relationship between the first upper transition member 50a, the first lower transition member 51a, and the first side connecting member 100 is also fixed. Although not shown, the positional relationship between the first upper transition member 50a, the first lower transition member 51a, and the second side connecting member 110 is fixed in the same manner as the first side connecting member 100.

[0068] According to the configuration in which the first frame body 40a and the second frame body 40b (and thus the first unit 20a and the second unit 20b) are connected by the connecting members 100 and 110, the first frame body 40a and the second frame body 40b can be connected by using members for closing the openings 41a and 41b of the frame bodies 40a and 40b, thereby reducing the number of parts.

[0069] As shown in FIGS. 5 to 7 , the first upper transition member 50a has two first positioning portions 54a on each of its two edges in the first direction D1. Similarly, the first lower transition member 51a has two first positioning portions 55a on each of its two edges in the first direction D1. The two first positioning portions 54a on one side in the first direction D1 and the two first positioning portions 55a on that side protrude toward the first side connecting member 100. In this embodiment, the first positioning portions 54a, 55a are in the form of pins that are inserted into holes drilled in the first upper transition member 50a or the first lower transition member 51a and attached by being pressed in or secured with an adhesive.

[0070] As shown in FIG. 2 , the first side connecting member 100 has a plurality of positioning through holes 101 formed at positions corresponding to the first positioning portions 54 a, 55 a. By inserting the first positioning portions 54 a, 55 a into these positioning through holes 101, the first transition members 50 a, 51 a are accurately positioned relative to the first side connecting member 100. Although not shown, the first transition members 50 a, 51 a are accurately positioned relative to the second side connecting member 110 in a manner similar to that of the first side connecting member 100. With this configuration, by inserting the first positioning portions 54 a, 55 a into the positioning through holes 101, the relative positions of the first side connecting member 100 and the second side connecting member 110 (and thus the first unit 20 a and second unit 20 b) and the first upper transition member 50 a and the first lower transition member 51 a are fixed on a plane perpendicular to the first direction D1. This suppresses distortion of the first upper transfer member 50a and the first lower transfer member 51a, improving the accuracy of the positions and orientations of the first mirrors 71a, 72a, 73a attached to the first upper transfer member 50a and the first lower transfer member 51a.

[0071] In this embodiment, the first frame body 40a has an open-bottom cylindrical shape and can be manufactured by extrusion molding. This reduces manufacturing costs compared to manufacturing the first frame body 40a by die casting or injection molding. In this embodiment, the first upper transfer member 50a, the first lower transfer member 51a, the first sensor accommodating portion 61a, and the first tubular portion 62a are also manufactured by extrusion molding. This further reduces manufacturing costs. However, at least a portion of the first frame body 40a, the first upper transfer member 50a, the first lower transfer member 51a, the first sensor accommodating portion 61a, and the first tubular portion 62a may be manufactured by other molding methods.

[0072] The first frame 40a is constructed by assembling multiple components, namely, the first component 42a, the second component 43a, the third component 44a, the fourth component 45a, and the fifth component 46a. Therefore, compared to molding the entire first frame 40a as a single unit, the first frame 40a can be manufactured using a smaller-scale extrusion molding device. Furthermore, by replacing the first upper transition member 50a and the first lower transition member 51a, the position and orientation of the first mirrors 71a, 72a, and 73a can be changed to change the optical path length. In other words, even if the optical path length needs to be changed, the first frame 40a can be reused as is without remaking it. However, the first frame 40a may be an integrally molded product that does not require assembly. In this case, the first upper transition member 50a and the first lower transition member 51a may also be integrally formed with the first frame 40a.

[0073] According to the optical detection unit 20 described above, the first frame 40a has a bottomless cylindrical shape, i.e., a hollow shape, making it lighter than conventional frames manufactured by die casting or injection molding. Furthermore, because the first frame 40a has a bottomless cylindrical shape, during the manufacturing stage of the optical detection unit 20, the frame intermediate product (in this embodiment, an extrusion molded product) can be cut at a desired position in its longitudinal direction (i.e., the first direction D1) to obtain a shorter first frame 40a. Alternatively, multiple frame intermediate products can be joined in the longitudinal direction to obtain a longer first frame 40a. In this way, the first frame 40a whose longitudinal length has been adjusted to a desired length can be used for multiple sorters 10 with various processing capacities (in other words, multiple sorters 10 with different chute 23 widths). In other words, the frame intermediate product can be used in common for multiple optical detection units 20 used in multiple sorters 10 with different processing capacities. Therefore, the manufacturing cost of the sorting machine 10 with various processing capacities can be reduced.

[0074] Furthermore, according to the optical detection unit 20, the first background 75a is located closer to the second frame 40b (i.e., the detection position 14) than the first light source 30a, which allows the size of the first frame 40a in the second direction D2 to be more compact than the conventional optical detection unit 20. In the conventional optical detection unit 20, the background is located farther from the detection position than the light source to prevent blocking of light from the light source. Moreover, as shown in FIG. 7 , the first optical path 64a of the light detected by the first optical sensor 60a extends in a fan-shaped manner in the first direction D1 as viewed from the first optical sensor 60a not only between the first optical sensor 60a and the detection position 14 but also beyond the detection position 14 between the detection position 14 and the second background 75b. Therefore, the greater the distance between the second background 75b and the first optical sensor 60a (in other words, the first frame 40a), the greater the width of the second background 75b, and therefore the second frame 40b, in the first direction D1. However, according to this embodiment, the second background 75b is positioned closer to the first optical sensor 60a than in the conventional optical detection unit, which shortens the distance over which the optical path 64a extends to the second background 75b (i.e., reduces the width of the optical path 64a in the first direction D1). Therefore, the size of the second frame 40b in the first direction D1 can be made more compact.

[0075] In particular, in this embodiment, since the second background 75b is located on the second transparent member 48b, the distance between the second background 75b and the first optical sensor 60a can be made smaller, and as a result, the size of the second frame body 40b in the first direction D1 can be made even more compact.

[0076] Furthermore, in this embodiment, an LED having a relatively high directivity is used as the first light source 30a. Therefore, it is easy to set a layout in which the light 31a emitted from the first light source 30a toward the detection position 14 is not blocked by the first background 75a. However, the first light source 30a is not limited to an LED, and may be any type of light source (for example, a laser light source).

[0077] Although the embodiments have been described above, the above-described embodiments are intended to facilitate understanding of the present teachings and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof. Furthermore, any combination or omission of each component described in the claims and specification is possible within the scope of solving at least part of the above-described problems or achieving at least part of the effects.

[0078] For example, any electromagnetic wave source may be provided instead of or in addition to the first light source 30a and / or the second light source 30b that emit visible light. Such electromagnetic wave sources may include, for example, a near-infrared source and / or an X-ray source.

[0079] Alternatively, one of the first light source 30a and the second light source 30b may be omitted, or one of the first optical sensor 60a and the second optical sensor 60b may be omitted. In this case, one of the first frame body 40a and the second frame body 40b may be omitted. For example, if the second frame body 40b is omitted, the first opening 41a of the first frame body 40a may be closed with a closure plate. In this case, the first upper transition member 50a, the first lower transition member 51a, and the closure plate may be positioned in a manner similar to that of the first side connecting member 100.

[0080] Alternatively, the first frame body 40a and the second frame body 40b may not be connected. In this case, the first opening 41a of the first frame body 40a and the second opening 41b of the second frame body 40b may be closed with a closing plate. Furthermore, the first upper transition member 50a, the first lower transition member 51a, and the closing plate may be positioned in the same manner as the first side connecting member 100.

[0081] Alternatively, the first mirrors 71a, 72a, 73a may be attached directly to the first upper transition member 50a and the first lower transition member 51a without using the first holding members 81a, 82a, 83a.

[0082] Furthermore, instead of the configuration in which light is irradiated onto the object 11 after it has fallen from the chute 23 and the light associated with the object 11 is detected by the optical sensors 60a and 60b, a configuration in which light is irradiated onto the object 11 while it is sliding down the chute 23 and the light associated with the object 11 is detected may be employed. Alternatively, a belt conveyor may be used as the transport means instead of the chute 23. In this case, a configuration in which light is irradiated onto the object 11 falling from one end of the belt conveyor and the light associated with the object 11 is detected may be employed, or a configuration in which light is irradiated onto the object 11 being transported on the belt conveyor and the light associated with the object 11 is detected may be employed.

[0083] Furthermore, the present invention is not limited to optical sorting machines and can be realized in various forms. For example, the present invention may be realized as an optical measurement device for optically measuring the state of an object. Such a measurement device may have a configuration in which the sorting unit 26 and the defective product discharge trough 25 are removed from the above-mentioned sorting machine 10. Alternatively, the present invention may be realized as an optical detection unit.

[0084] 10...optical sorting machine, 11, 12, 13...object, 14...detection position, 15...controller, 20...optical detection unit, 20a...first unit, 20b...second unit, 21...storage tank, 22...feeder, 23...chute, 24...good product discharge trough, 25...defective product discharge trough, 26...sorting section, 27...spray nozzle, 28...valve, 29...air, 30a...first light source, 30b...second light source, 31a...first light, 31b...second light, 32a...first upper light source, 32b...second 2 upper light source, 33a...first lower light source, 33b...second lower light source, 34a...first background light source, 34b...second background light source, 35a...first side plate, 35b...second side plate, 40a...first frame body, 40b...second frame body, 41a...first opening, 41b...second opening, 42a, 42b...first member, 43a, 43b...second member, 44a, 44b...third member, 45a, 45b...fourth member, 46a, 46b...fifth member, 47a...connecting hole, 48a...first transparent member, 48 b...second transparent member, 50a...first upper transition member, 50b...second upper transition member, 51a...first lower transition member, 51b...second lower transition member, 52a...first inclined portion, 52b...second inclined portion, 53a...first raised portion, 53b...second raised portion, 54a, 55a...first positioning portion, 54b, 55b...second positioning portion, 57a...connecting hole, 60a...first optical sensor, 60b...second optical sensor, 61a...first sensor accommodating portion, 61b...second sensor accommodating portion, 62a...first cylindrical portion, 62b...second cylindrical portion, 63a...first optical axis, 63b...second optical axis, 64a...first optical path, 71a, 72a, 73a...first mirror, 75a...first background, 75b...second background, 81a, 82a, 83a...first holding member, 81b, 82b, 83b...second holding member, 90a...first biasing member, 100...first side connecting member, 101...positioning through hole, 102...fixing through hole, 103...bolt, 110...second side connecting member, 181a...first member, 182a...Second member, 183a...first positioning surface, D1...first direction, D2...second direction, D3...transport direction.

Claims

1. An optical detection unit for an optical measurement device, comprising: an optical sensor configured to optically detect an object; a mirror configured to bend the optical path to guide light to the optical sensor; and a frame having an open-bottom cylindrical shape with two opposing openings, and housing at least the mirror.

2. An optical detection unit for an optical measuring device, comprising a first unit and a second unit, each of the first unit and the second unit comprising: a frame body having a bottomless cylindrical shape with two openings facing each other in a first direction; an optical sensor housed within the frame body or attached to the frame body and configured to optically detect an object; and a mirror housed within the frame body and configured to bend the optical path to guide light to the optical sensor, the optical detection unit further comprising a connecting member that fixedly connects the first frame body, which is the frame body of the first unit, and the second frame body, which is the frame body of the second unit, in a state where they are lined up in a second direction perpendicular to the first direction.

3. An optical detection unit according to claim 2, wherein each of the first unit and the second unit comprises a transition member spanning two opposing inner surfaces of the frame, and the mirror is attached directly or indirectly to the transition member.

4. An optical detection unit as defined in claim 2 or claim 3, wherein the connecting member includes: a first-side connecting member that connects the first frame body and the second frame body while blocking the opening on a first side of the two opposing openings of the first frame body and the opening on the first side of the two opposing openings of the second frame body; and a second-side connecting member that connects the first frame body and the second frame body while blocking the opening on a second side opposite to the first side of the two opposing openings of the first frame body and the opening on the second side of the two opposing openings of the second frame body.

5. An optical detection unit according to claim 3 or claim 4 which depends on claim 3, wherein the transition member has a positioning portion extending toward the connecting member, and the connecting member has a positioning hole into which the positioning portion is inserted.

6. An optical detection unit according to claim 3, claim 4 which includes claim 3 as a dependent element, and claim 5, wherein the transition member has a finished surface for mounting the mirror.

7. An optical detection unit according to any one of claims 2 to 6, wherein each of the first frame body and the second frame body is an extrusion molded product.

8. An optical detection unit as claimed in any one of claims 2 to 7, comprising: a first light source configured to irradiate light towards the position at which the optical sensor detects the object and housed within the first frame; a second light source configured to irradiate light towards the position at which the optical sensor detects the object and housed within the second frame; a first background located within or on the first frame, which forms a background to the field of view of the second optical sensor that is the optical sensor of the second unit, but is outside the field of view of the first optical sensor that is the optical sensor of the first unit; and a second background located within or on the second frame, which forms a background to the field of view of the first optical sensor, but is outside the field of view of the second optical sensor, wherein the first background is located closer to the second frame than the first light source, and the second background is located closer to the first frame than the second light source.

9. A measuring device or sorting machine comprising an optical detection unit according to any one of claims 1 to 8.

Images