Code reader and image processor

Abstract

To improve the degree of freedom in installation by reducing a protruding amount of a code reader from a frame to a conveyance device side when the code reader is attached to an exterior frame for usage.SOLUTION: A stationary code reader 1A includes: a housing 60 which is long along a first direction, and has a light reception window 622 transmitting light to a lateral side; an illumination unit 2a which is stored in the housing 60, and has an illumination surface formed in parallel with the light reception surface 622 along a first direction; an imaging unit which has an image sensor installed in the first direction; a mirror 33 which folds back an optical path corresponding to the field of vision of the imaging unit to a direction of the light reception window 622 in the housing 60; and an attachment unit which is provided on the lateral side of the housing 60, and attaches the housing 60 to an exterior frame.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a code reader that reads a code attached to a workpiece transported by a transport device, and an image processing device that processes an image of the workpiece. [Background technology]

[0002] This type of code reader is used, for example, in logistics sites to read codes attached to workpieces transported by a transport device. The code reader disclosed in Patent Document 1 includes an illumination unit that illuminates the workpiece and an imaging unit that receives light reflected from the workpiece and generates a code image. The illumination unit is made up of multiple illumination blocks, and a light-receiving window that transmits light reflected from the workpiece is provided in the area surrounded by the illumination blocks on the front side of the code reader. The light that passes through the light-receiving window is received by the imaging unit, which is located behind the illumination blocks. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-149656 Summary of the Invention [Problem to be solved by the invention]

[0004] However, a code reader may be used while attached to an external frame. When a code reader is attached to a frame and used, if the code reader protrudes from the frame toward the conveying device, interference with the workpiece being conveyed by the conveying device is likely to occur, so there is a demand to minimize the amount by which the code reader protrudes from the frame toward the conveying device.

[0005] In this regard, in the code reader of Patent Document 1, multiple illumination blocks are arranged to surround a light receiving window, and the imaging unit is located behind these illumination blocks, which makes the depth dimension long. Therefore, if the code reader of Patent Document 1 is to be mounted on a frame for use, it is conceivable that the code reader would protrude significantly toward the conveying device. This can be a factor that reduces the degree of freedom in installing the code reader.

[0006] The present disclosure has been made in consideration of such points, and its purpose is to improve installation flexibility by reducing the amount of protrusion of the code reader from the frame toward the conveying device when the code reader is attached to an external frame for use. [Means for solving the problem]

[0007] To achieve the above object, this aspect can be premised on a stationary code reader that is configured to be usable while attached to an external frame and that reads a code attached to a workpiece transported by a transport device. The code reader includes: a housing that is elongated along a first direction and has a light-receiving window that transmits light laterally; an illumination unit that is housed in the housing and forms an irradiation surface for irradiating the workpiece with illumination light aligned with the light-receiving window along the first direction; an imaging unit that includes an image sensor that has a two-dimensional light-receiving surface and is installed within the housing facing the first direction, and a lens that projects an image corresponding to the code attached to the workpiece onto the light-receiving surface of the image sensor within the housing; a mirror that, within the housing, folds an optical path corresponding to the field of view of the imaging unit toward the light-receiving window; a decoder that decodes the code attached to the workpiece based on the image generated by the imaging unit; and an attachment unit that is provided on the side of the housing different from the light-receiving window and for attaching the housing to the external frame.

[0008] With this configuration, the housing is long along the first direction, so for example, a housing arranged so that the longitudinal direction of the external frame coincides with the first direction of the housing can be attached to the external frame using the attachment part. In this housing, the irradiation surface of the illumination light formed by the illumination part is aligned with the light-receiving window along the first direction, so when the optical axis direction of the illumination light irradiating the code is taken as the reference, the dimension of the housing in that direction is short. Therefore, the amount of protrusion of the code reader from the external frame toward the transport device is reduced.

[0009] A communication interface for transmitting information relating to the result of the decoding process by the decoder can be provided at the end of the housing in the first direction. In this case, the direction when connecting a communication line to the communication interface is along the first direction, so the amount of protrusion of the code reader including the communication line toward the conveying device is reduced. [Effects of the Invention]

[0010] As described above, when the code reader is attached to an external frame for use, the amount of protrusion of the code reader from the frame toward the transport device is reduced, thereby improving the degree of freedom in installation. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view illustrating a code reader according to an embodiment of the present invention in operation. [Figure 2] FIG. 2 is a front view showing the installed state of the code reader. [Figure 3] FIG. 3 is a block diagram of the code reader. [Figure 4] FIG. 4 is a schematic diagram showing the relationship between the Scheimpflug optical system and the focal plane. [Figure 5] FIG. 5 is a perspective view of the code reader. [Figure 6] FIG. 6 is a front view of the code reader. [Figure 7] FIG. 7 is a bottom view of the code reader. [Figure 8] FIG. 8 is a perspective view of the code reader with the box-shaped case removed. [Figure 9] FIG. 9 is an enlarged cross-sectional view of the joint between the box-shaped case and the lid-shaped case. [Figure 10] FIG. 10 is an enlarged cross-sectional view of the joint between the box-shaped case and the window frame. [Figure 11] FIG. 11 is a cross-sectional view of the first illumination unit. [Figure 12] FIG. 12 is a vertical cross-sectional view of the lid-like case in the left-right direction. [Figure 13] FIG. 13 is a vertical cross-sectional view of the lid-like case in the depth direction. [Figure 14] FIG. 14 is a perspective view of the lens holder. [Figure 15] FIG. 15 is a view equivalent to FIG. 14, showing a state in which the sensor substrate has been removed. [Figure 16] FIG. 16 is a view equivalent to FIG. 14, showing a state in which the sensor holder is removed. [Figure 17] FIG. 17 is a diagram for explaining how the bottom surface of a workpiece is imaged during transportation. [Figure 18] FIG. 18 is a flowchart showing an example of a series of processes from imaging to output of the read result. [Figure 19] FIG. 19 is a side view showing an example of attaching a code reader to a frame. [Figure 20] FIG. 20 is a view equivalent to FIG. 19, but with a different angle. [Figure 21] FIG. 21 is a front view of the device attached to the frame. [Figure 22] FIG. 22 is a bottom view of the housing with the bracket. [Figure 23] FIG. 23 is a side view showing an example of installation in which the optical axis is perpendicular to the reference plane. [Figure 24] FIG. 24 is a side view showing an example of installation using a mirror. [Figure 25] FIG. 25 is a side view showing a comparison of installation examples in which brackets are attached to different sides. [Figure 26]FIG. 26 is a diagram showing a schematic structure of a code reader according to a first example of another embodiment. [Figure 27] FIG. 27 is a diagram showing the field of view and depth of the code reader according to the first example. [Figure 28] FIG. 28 is a diagram showing the field of view and depth of the code reader according to the second example. [Figure 29] FIG. 29 is a diagram showing a schematic structure of a code reader according to the third example. [Figure 30] FIG. 30 is a diagram showing a schematic structure of a code reader according to the fourth example. [Figure 31] FIG. 31 is a diagram showing the field of view and depth of a code reader according to a fifth example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0013] FIG. 1 is a diagram schematically illustrating code readers 1A, 1B, 1C, and 1D according to an embodiment of the present invention during operation. FIG. 2 is a front view illustrating the installed state of code readers 1A, 1B, 1C, and 1D. This example illustrates a case in which multiple code readers 1A, 1B, 1C, and 1D are used at a logistics site that handles multiple workpieces W. A conveying device B is installed at the logistics site to sequentially convey multiple workpieces W in a predetermined conveying direction. The conveying direction of the workpieces W is indicated by arrow A in FIG. 1; therefore, the right side of FIG. 1 is the upstream side of the conveying direction, and the left side of FIG. 1 is the downstream side of the conveying direction.

[0014] The conveying device B has multiple conveying mechanisms B1 and B2. Each conveying mechanism B1 and B2 is, for example, a belt conveyor or a roller conveyor, and includes an upstream conveying mechanism B1 and a downstream conveying mechanism B2. The upper surfaces of the upstream conveying mechanism B1 and the downstream conveying mechanism B2 form a conveying surface. In this embodiment, the conveying direction of the workpiece W is defined as the Y direction, the direction perpendicular to the Y direction on the conveying surface is defined as the X direction, and the direction perpendicular to both the X and Y directions is defined as the Z direction. In logistics sites, the X and Y directions are often approximately horizontal, but the Y direction may be inclined relative to the horizontal plane. The X direction can also be called the width direction of the conveying mechanisms B1 and B2, or the longitudinal direction of the gap between the conveying device B. The Z direction can also be called the height direction (up and down). Note that these direction definitions are for convenience of explanation and do not limit the directions during use.

[0015] The upstream transport mechanism B1 and the downstream transport mechanism B2 are spaced apart in the transport direction. The size (dimension) of the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2 is not particularly limited, but is set so that the smallest workpiece W to be transported does not fall through the gap and is smoothly transferred from the upstream transport mechanism B1 to the downstream transport mechanism B2. The longitudinal dimension of the gap (dimension in the X direction) is approximately the same as the width (dimension in the X direction) of the transport mechanisms B1 and B2, but this is also not particularly limited.

[0016] The upstream transport mechanism B1 and the downstream transport mechanism B2 are supported on a floor C (shown in FIG. 2) by members such as legs B3. Because the transport surfaces of the upstream transport mechanism B1 and the downstream transport mechanism B2 are positioned a predetermined distance above the floor C, a space may be formed below the upstream transport mechanism B1 and the downstream transport mechanism B2.

[0017] 1 and 2 show an example in which four code readers 1A, 1B, 1C, and 1D are used during operation, but the number of code readers used during operation is not limited to four and can be any number of three or less, or five or more. Code reader 1A is the first code reader 1A, code reader 1B is the second code reader 1B, code reader 1C is the third code reader 1C, and code reader 1D is the fourth code reader 1D.

[0018] The first to fourth code readers 1A, 1B, 1C, and 1D are stationary code readers that are configured to be usable when attached to an external frame (hereinafter simply referred to as the frame) 830, and that read codes attached to workpieces W transported by the transport device B. When these stationary code readers 1A, 1B, 1C, and 1D are in operation, they are performing the operation of sequentially reading the codes on the workpieces W transported by the transport device B.

[0019] The frame 830 is a frame-shaped frame formed to surround the transport device B, and includes a lower member 831 disposed below the transport device B and extending in the width direction (X direction) of the transport device B, a pair of side members 832 extending upward (Z direction) from both longitudinal sides of the lower member 831, and an upper member 833 extending in the width direction of the transport device B so as to connect the upper ends of the pair of side members 832. The frame 830 is fixed to, for example, a floor C (shown in FIG. 2) or the like.

[0020] The housing 60 of the first code reader 1A for reading the code attached to the bottom surface of the workpiece W is attached to the lower member 831 via a bracket 810. Because the lower member 831 is located below the conveying surface of the conveying device B, the installation position of the first code reader 1A attached to the lower member 831 is below the conveying surface of the conveying device B. The optical axis of the first code reader 1A attached to the lower member 831 faces upward, and the field of view of the first code reader 1A includes the gap between the upstream conveying mechanism B1 and the downstream conveying mechanism B2.

[0021] Since the field of view of the first code reader 1A includes the gap between the upstream conveying mechanism B1 and the downstream conveying mechanism B2, when the bottom surface of the workpiece W being conveyed passes through the gap between the upstream conveying mechanism B1 and the downstream conveying mechanism B2, the bottom surface can be imaged by the imaging unit 3 (shown in FIG. 3) of the first code reader 1A. A code may be attached to the bottom surface of the workpiece W. If a code is attached to the bottom surface of the workpiece W, the first code reader 1A is installed at an installation position below the conveying surface of the conveying device B, so that the code attached to the bottom surface of the workpiece W can be read from below the conveying surface of the conveying device B through the gap between the upstream conveying mechanism B1 and the downstream conveying mechanism B2.

[0022] A second code reader 1B for reading a code attached to one side surface of the workpiece W is attached to one side member 832 via a bracket (not shown) similar to that of the first code reader 1A. The optical axis of the second code reader 1B attached to one side member 832 is set to face one side surface of the workpiece W.

[0023] A housing 60 of a third code reader 1C for reading a code attached to the other side surface of the workpiece W is attached to the other side member 832 via a bracket 810 similar to that of the first code reader 1A. The optical axis of the third code reader 1C attached to the other side member 832 is set to face the other side surface of the workpiece W.

[0024] A housing 60 of a fourth code reader 1D for reading a code attached to the upper surface of a workpiece W is attached to the upper member 833 via a bracket 810 similar to that of the first code reader 1A. The optical axis of the fourth code reader 1D attached to the upper member 833 faces downward.

[0025] The structure of the frame 830 described above is an example, and it need not be a frame-shaped frame. For example, it may be a frame consisting of only the lower member 831, a frame consisting of only the side member 832, or a frame consisting of only the upper member 833. It may also be a frame including any two of the lower member 831, the side member 832, and the upper member 833. Code readers do not need to be attached to all of the lower member 831, the side member 832, and the upper member 833; it is sufficient that code readers are attached to any one or any two or more of the lower member 831, the side member 832, and the upper member 833. The frame may be fixed to, for example, the conveying device B, another member, equipment, or the like. The frame may have a linear shape, or may be curved or bent.

[0026] The code attached to the workpiece W includes both barcodes and two-dimensional codes. Examples of two-dimensional codes include QR Code (registered trademark), Micro QR Code, Data Matrix (Data code), Veri Code, Aztec Code, PDF417, and Maxi Code. Two-dimensional codes come in stack and matrix types, and the present invention can be applied to either type of two-dimensional code. The code may be attached by printing or engraving directly onto the workpiece W, or by printing on a label and then attaching it to the workpiece W; the means and method are not important.

[0027] As shown in FIG. 1, the first to fourth code readers 1A, 1B, 1C, and 1D are connected to a computer 200 and a programmable logic controller (PLC) 201 by signal lines 200a and 201a, respectively. However, this is not limiting. The first to fourth code readers 1A, 1B, 1C, and 1D, the computer 200, and the PLC 201 may each have a built-in wireless communication module, and the first to fourth code readers 1A, 1B, 1C, and 1D may be wirelessly connected to the computer 200 and the PLC 201. The PLC 201 is a control device for sequentially controlling the conveyance device B and the first to fourth code readers 1A, 1B, 1C, and 1D, and a general-purpose PLC may be used. The computer 200 may be a general-purpose or dedicated electronic computer, a portable terminal, or the like.

[0028] Furthermore, during operation, the first to fourth code readers 1A, 1B, 1C, and 1D receive a read start trigger signal, which specifies the timing to start code reading, from the PLC 201 via the signal line 201a. Then, the first to fourth code readers 1A, 1B, 1C, and 1D capture an image of the code and perform decoding processing based on this read start trigger signal. Thereafter, the decoded results are transmitted to the PLC 201 via the signal line 201a. In this way, during operation of the first to fourth code readers 1A, 1B, 1C, and 1D, input of the read start trigger signal and output of the decoded results are repeatedly performed via the signal line 201a between the first to fourth code readers 1A, 1B, 1C, and 1D and an external control device such as the PLC 201. As described above, the input of the read start trigger signal and the output of the decoded result may be performed via the signal line 201a between the first to fourth code readers 1A, 1B, 1C, and 1D and the PLC 201, or via other signal lines (not shown). For example, a sensor for detecting the arrival of the work W may be directly connected to the first to fourth code readers 1A, 1B, 1C, and 1D, and the read start trigger signal may be input from the sensor to the first to fourth code readers 1A, 1B, 1C, and 1D.

[0029] The first to fourth code readers 1A, 1B, 1C, and 1D are the same. The first code reader 1A will be described in detail below with reference to Fig. 3. The first code reader 1A includes an illumination unit 2, an imaging unit 3, a control unit 4, a storage unit 5, a communication unit 6, a flat mirror 33, and a housing 60. The illumination unit 2, the imaging unit 3, the control unit 4, the storage unit 5, the communication unit 6, and the flat mirror 33 are stored in the housing 60.

[0030] The control unit 4 includes an imaging control unit 41 that controls the imaging unit 3, an illumination control unit 42 that controls the illumination unit 2, a code detection unit 43, and a decoding unit 44. The storage unit 5 can be configured with a readable and writable storage device such as an SSD (Solid State Drive). The storage unit 5 can store, for example, various programs, decoding results, image data, setting information, etc., and includes a decoding result storage unit 51, an image data storage unit 52, and a setting storage unit 53. Although not shown, the decoding result storage unit 51, the image data storage unit 52, and the setting storage unit 53 may be provided in separate storage devices.

[0031] The communication unit 6 is a part that executes communication with the computer 200 and the PLC 201. Setting information from the computer 200 is received by the control unit 4 via the communication unit 6. Furthermore, a reading start trigger signal from the PLC 201 is received by the control unit 4 via the communication unit 6. Information regarding the decoded result by the first code reader 1A is transmitted to the computer 200 and the PLC 201 via the communication unit 6. Furthermore, the communication unit 6 receives, for example, the dimensions of the gaps formed between the multiple conveying mechanisms B1 and B2 of the conveying device B, the conveying speed of the conveying device B, etc. The gap dimensions and conveying speed can be input in advance by the user into the computer 200, etc. The input gap dimensions and conveying speed are stored in the computer 200, and after being transmitted from the computer 200, the gap dimensions and conveying speed are received and acquired by the communication unit 6.

[0032] The illumination unit 2 is a part that irradiates illumination light onto the workpiece W. When the first code reader 1A is attached to the lower member 831 of the frame 830, the illumination range of the illumination light from the illumination unit 2 includes the gap between the upstream conveying mechanism B1 and the downstream conveying mechanism B2. In this case, since the first code reader 1A is installed below the conveying surface of the conveying device B, the illumination unit 2 irradiates illumination light from below the conveying surface toward the gap. As a result, when the bottom surface of the workpiece W being conveyed passes through the gap between the upstream conveying mechanism B1 and the downstream conveying mechanism B2, the bottom surface can be illuminated by the illumination unit 2. When a code is attached to the bottom surface of the workpiece W, the code attached to the bottom surface of the workpiece W can be illuminated by the illumination unit 2.

[0033] Although not essential, the illumination unit 2 includes a first illumination unit 2a and a second illumination unit 2b. The first illumination unit 2a and the second illumination unit 2b are components that irradiate illumination light onto a focal plane 5 (shown in FIG. 4) of a Scheimpflug optical system 31, which will be described later. The first illumination unit 2a and the second illumination unit 2b include light-emitting elements such as light-emitting diodes (LEDs). The illumination unit 2 may be configured as a single illumination unit without including the first illumination unit 2a and the second illumination unit 2b. Note that the Scheimpflug optical system 31 is not essential, and the present invention can be applied even when the Scheimpflug optical system 31 is not included.

[0034] The illumination unit 2 and the imaging unit 3 may be integrated, or may be separate units. The illumination unit 2 is controlled by an illumination control unit 42, which switches the illumination unit 2 on and off and changes the brightness when it is on. When a reading start trigger signal is input from the PLC 201, the illumination control unit 42 turns on the illumination unit 2 for a predetermined time and turns it off after the predetermined time has elapsed.

[0035] The imaging unit 3 is a part that images the workpiece W through the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2, generates a code image including the code, and outputs the image to the control unit 4. The imaging units 3 of the second to fourth code readers 1B to 1D are parts that image the workpiece W from above the transport surface of the transport mechanism B, generate a code image including the code, and output the image to the control unit 4. The imaging unit 3 has a Scheimpflug optical system 31 and a pre-processing circuit 32. As shown in FIG. 4, the Scheimpflug optical system 31 has a lens 31a and an image sensor 31b having a two-dimensional light-receiving surface inclined with respect to the optical axis 10 of the lens 31a. The lens 31a is an imaging lens that collects light reflected from the bottom surface of the workpiece W. Light incident on the lens 31a is emitted toward the light-receiving surface of the image sensor 31b and forms an image on the light-receiving surface, thereby projecting an image corresponding to the code attached to the workpiece W onto the light-receiving surface of the image sensor 31b.

[0036] In this example, since the Scheimpflug optical system 31 is included, the focal plane 7 is formed to extend in the V direction of the image sensor 31b, and the focal plane 7 is inclined in the V direction of the image sensor 31b.

[0037] The image sensor 31b includes a light-receiving element such as a CCD (charge-coupled device) or a CMOS (complementary metal oxide semiconductor) that converts the code image obtained through the lens 31a into an electrical signal. An image including the code is generated based on the amount of light received on the light-receiving surface of the image sensor 31b. The image sensor 31b has multiple imaging elements arranged in rows and columns, with the row direction substantially coinciding with the direction from the near side to the far side of the focal plane of the Scheimpflug optical system 31. The aspect ratio of the image sensor 31b is set smaller than the aspect ratio of a light-receiving window 622, which will be described later. The image sensor 31b is configured to be able to partially output signals from the imaging element corresponding to the light-receiving window 622 among the multiple imaging elements.

[0038] That is, if a line sensor were used as the image sensor, high-speed readout would be possible, but the frame rate would need to be extremely high to read the code, which could increase the amount of heat generated by the illumination unit 2. In this regard, in this embodiment, an area sensor in which multiple image pickup elements are arranged in row and column directions is used as the image sensor 31b, and only the portion (some of the rows) corresponding to the light receiving window 622 is partially read out, thereby making it possible to achieve both heat suppression and high-speed readout.

[0039] The image generated by the image sensor 31b is input to a pre-processing circuit 32. The pre-processing circuit 32 may be provided as needed and is not essential.

[0040] The preprocessing circuit 32 is configured with an integrated circuit such as an FPGA (Field Programmable Gate Array), and is a part that performs various preprocessing operations on the image output from the image sensor 31b. The preprocessing operations include, for example, various filter processes. The imaging unit 3 outputs the image that has been preprocessed by the preprocessing circuit 32 to the control unit 4. The preprocessing by the preprocessing circuit 32 may be performed as needed, and an image that has not been preprocessed may be output to the control unit 4. The image output to the control unit 4 is stored in the image data storage unit 52 of the storage unit 5.

[0041] The imaging unit 3 is controlled by the imaging control unit 41. When a read start trigger signal is input from the PLC 201, the imaging control unit 41 generates an image by exposing the image sensor 31b for a predetermined exposure time. The imaging control unit 41 controls the imaging unit 3 to apply a predetermined gain to the image generated by the image sensor 31b and, if necessary, amplify the image brightness through digital image processing. The imaging control unit 41 also determines the frame rate (number of images taken per second) of the imaging unit 3 based on the gap size (gap width) between the transport mechanisms B1 and B2 and the transport speed received via the communication unit 6. The imaging control unit 41 increases the frame rate of the imaging unit 3, for example, the faster the transport speed. The frame rate can be set within a range of 500 fps to 5000 fps, for example. A higher frame rate requires more intense light to obtain sufficient brightness with a short exposure time, which proportionally increases the heat generated by the illumination unit 2. It should be noted that the second to fourth code readers 1B to 1D do not capture images through the gap between the transport mechanisms B1 and B2, and therefore it is not necessary to determine the frame rate based on the size of the gap between the transport mechanisms B1 and B2.

[0042] As shown in FIGS. 5 to 7, the first code reader 1A includes a housing 60 that houses the illumination unit 2, the imaging unit 3, and the control unit 4. The housing 60 may house the imaging unit 3 and the control unit 4, but not the illumination unit 2. In this case, the illumination unit 2 is configured separately from the housing 60 that houses the imaging unit 3 and the control unit 4, but is controlled in synchronization with the control unit 4 when capturing an image of the workpiece W. An illumination unit configured separately from the housing 60 is also referred to as an external illumination unit.

[0043] The housing 60 has an elongated shape extending along a predetermined direction (first direction). As shown in FIG. 2, the first code reader 1A and the fourth code reader 1D are installed so that the first direction is the horizontal direction (X direction). On the other hand, the second code reader 1B and the third code reader 1C are installed so that the first direction is the vertical direction (Z direction). In this way, the installation orientation of the code readers 1A, 1B, 1C, and 1D can be set depending on the structure of the conveyance device B and which side of the workpiece W the code is to be read from, and is not limited to the orientation shown in the figure. For example, the installation orientation may be inclined with respect to the X direction or the Z direction.

[0044] The housing 60 has a first side surface 61, a second side surface 62, a third side surface 63, and a fourth side surface 64, as well as a first end surface 65 and a second end surface 66. In this embodiment, the depth direction (front-rear direction), left-right direction, and up-down direction of the housing 60 are defined as shown in FIGS. 5 to 7. However, these definitions are for the convenience of explanation and do not limit the actual usage posture of the first code reader 1A. In reality, the first code reader 1A may be installed with the up-down direction reversed or with the up-down direction horizontal. Therefore, the directions in the following explanation can be changed taking into account the actual installation posture. In the cases shown in FIGS. 5 to 7, the first direction is the left-right direction. Therefore, the left-right dimension of the housing 60 is longer than the up-down and depth dimensions of the housing 60. Furthermore, the number of side surfaces of the housing 60 is not limited to six, and the housing 60 may have a shape with six or more side surfaces.

[0045] According to the above definition, the first side surface 61 is a surface (front surface) located on the front side of the housing 60 and has a shape elongated in the left-right direction. The second side surface 62 is a side surface adjacent to the first side surface 61, extending from an upper edge (one edge) of the first side surface 61 toward the rear side and also extending in the left-right direction, and is a surface (top surface) located on the upper side of the housing 60. The third side surface 63 is a side surface adjacent to the first side surface 61, extending from a lower edge (other edge) of the first side surface 61 toward the rear side and also extending in the left-right direction, and is a surface (bottom surface) located on the lower side of the housing 60. The fourth side surface 64 is a side surface located opposite the first side surface 61, extending in the up-down direction from the rear edge of the second side surface 62 to the rear edge of the third side surface and also extending in the left-right direction, and is a surface (rear surface) located on the rear side of the housing 60. The first side surface 61 and the fourth side surface 64 are approximately parallel to each other. The second side surface 62 and the third side surface 63 are substantially parallel to each other.

[0046] The first end surface 65 is the left end surface of the housing 60 and extends in the depth direction and the vertical direction. The second end surface 66 is the right end surface of the housing 60 and extends in the depth direction and the vertical direction. The first end surface 65 and the second end surface 66 are approximately parallel to each other.

[0047] The housing 60 has a box-shaped case 600 that forms a part of the housing 60 and a lid-shaped case 610 that forms the other part of the housing 60, and the box-shaped case 600 and the lid-shaped case 610 are integrated to form the housing 60. The lid-shaped case 610 is a first housing component, and the box-shaped case 600 is a second housing component.

[0048] The box-shaped case 600 is a component that constitutes the first side surface 61, the second side surface 62, the fourth side surface 64, the first end surface 65, and the second end surface 66, and is made of resin obtained by molding a resin material. The box-shaped case 600 is a component that constitutes the portions other than the third side surface 63, and therefore has a shape that is open on the third side surface 63 side. The lid-shaped case 610 is a component that constitutes the third side surface 63, and is made of metal. Examples of the metal material that constitutes the lid-shaped case 610 include metal materials with high heat conductivity, such as aluminum alloys. Therefore, the lid-shaped case 610 has better heat dissipation properties than the box-shaped case 600. On the other hand, the resin material that constitutes the box-shaped case 600 has inferior heat dissipation properties compared to the metal material that constitutes the lid-shaped case 610, but is set to have a low specific gravity. This allows the box-shaped case 600 to be made lighter.

[0049] The lid-like case 610 is attached to the box-like case 600 so as to cover the open portion of the box-like case 600. FIG. 8 shows the state with the box-like case 600 removed. As shown in this figure, a main packing 611 made of an elastic material such as rubber or a thermoplastic elastomer is disposed on a joint surface 610a of the lid-like case 610 where the lid-like case 610 joins with the box-like case 600. The main packing 611 is formed in an annular shape along the periphery of the lid-like case 610 and is held in a recessed state in a groove 600a formed in the box-like case 600, as shown in FIG. 9. The groove 600a of the box-like case 600 is a portion for storing the annular main packing 611, and therefore has an annular shape like the main packing 611 and is open toward the lid-like case 610. Although not shown, the groove for storing the main packing 611 may be formed in the lid-like case 610.

[0050] The main packing 611 stored in the groove 600a is in close contact with the joint surface 610a of the lid case 610 when the lid case 610 is integrated with the box case 600. This creates a seal between the box case 600 and the lid case 610 by the main packing 611, preventing external water and the like from penetrating into the housing 60.

[0051] 5 and 6, a light-transmitting member 620 that transmits light such as reflected light from the workpiece W and illumination light emitted from the illumination unit 2 is provided on the first side surface 61 of the box-shaped case 600. The light-transmitting member 620 is a member that constitutes a light-projecting window 621 that transmits illumination light emitted from the illumination unit 2 to the outside of the housing 60, and a light-receiving window 622 that transmits light reflected from the workpiece W to the inside of the housing 60. Because the light-projecting window 621 and the light-receiving window 622 are formed from the same light-transmitting member 620, the number of parts can be reduced. Furthermore, because the first side surface 61 is one side surface of the housing 60, the housing 60 is a member that has the light-projecting window 621 and the light-receiving window 622 on its side.

[0052] The light transmitting member 620 forms a plane extending along the left-right and up-down directions of the housing 60. The plane formed by the light transmitting member 620 can also be defined as an imaginary plane that includes the front surface (or back surface) of the light transmitting member 620. Note that the light transmitting member 620 does not have to be a perfect plane, and may be a surface that is gently curved to the extent that it can be optically regarded as a plane.

[0053] Light transmitting member 620 has an elongated shape that extends along the longitudinal direction of housing 60. Light transmitting member 620 is not particularly limited, but may be made of, for example, acrylic, glass, polycarbonate, etc. Note that light projecting window 621 and light receiving window 622 may be made of separate members.

[0054] 5, a window frame member 630 for fixing the light transmitting member 620 to the first side surface 61 of the box-shaped case 600 is provided on the first side surface 61 of the box-shaped case 600. The window frame member 630 has a rectangular shape that is long in the left-right direction so as to correspond to the external shape of the light transmitting member 620.

[0055] A window frame packing 631 (shown in FIG. 8) made of the same material as the main packing 611 is arranged on the joint surface (not shown) of the window frame member 630 with the box-shaped case 600. The window frame packing 631 is formed in an annular shape along the periphery of the window frame member 630, and is held in a stored state in a groove 630a formed in the window frame member 630 as shown in FIG. 10. The groove 630a of the window frame member 630 is the portion that stores the annular window frame packing 631, and therefore has an annular shape like the window frame packing 631 and is open to the box-shaped case 600 side. Although not shown, the groove that stores the window frame packing 631 may be formed in the box-shaped case 600.

[0056] Window frame packing 631 stored in groove 630a comes into close contact with the outer surface of light transmitting member 620 when window frame member 630 is integrated into box-shaped case 600. This creates a seal between light transmitting member 620 and window frame member 630 by window frame packing 631, preventing external water and the like from penetrating into housing 60 through window frame member 630.

[0057] The first illumination unit 2a is stored to the right of the center in the left-right direction of the housing 60. The second illumination unit 2b is stored to the left of the center in the left-right direction of the housing 60. In other words, the illumination unit 2 includes the first illumination unit 2a and the second illumination unit 2b that are arranged at an interval from each other in the longitudinal direction of the housing 60.

[0058] As shown in Fig. 11, the first illumination unit 2a has a light-emitting substrate 2i on which multiple LEDs are mounted, a wide-angle illumination lens 2j, and a narrow-angle illumination lens 2k. The light-emitting substrate 2i extends in the left-right and up-down directions. The multiple LEDs are mounted in a matrix on the front surface of the light-emitting substrate 2i, spaced apart from one another in the left-right and up-down directions. The wide-angle illumination lens 2j and the narrow-angle illumination lens 2k are attached to a common light-emitting substrate 2i. The multiple wide-angle illumination lenses 2j and the multiple narrow-angle illumination lenses 2k are integrally molded to protrude in the optical axis direction, and are configured as a single member.

[0059] The wide-angle illumination lens 2j is disposed to correspond to the plurality of LEDs mounted on the right side of the light-emitting substrate 2i, and is formed with a wide angle so that light from the LEDs can be irradiated over a wide range. The wide-angle illumination lens 2j and the LEDs corresponding to the wide-angle illumination lens 2j constitute a first illumination angle illumination unit in which the spread of the irradiated light is set to a first illumination angle.

[0060] The narrow-angle illumination lens 2k is disposed to correspond to the multiple LEDs mounted on the left side of the light-emitting substrate 2i, and is formed with a narrow angle so that it can irradiate illumination light over a narrower range than the wide-angle illumination lens 2j. The narrow-angle illumination lens 2k and the LED corresponding to the narrow-angle illumination lens 2k form a second illumination-angle illumination unit in which the spread of the irradiated light is set to a second illumination angle that is wider than the first illumination angle. The wide-angle illumination lens 2j and the LED corresponding to the wide-angle illumination lens 2j, and the narrow-angle illumination lens 2k and the LED corresponding to the narrow-angle illumination lens 2k are aligned in the longitudinal direction of the housing 60.

[0061] The dimension in the optical axis direction of the narrow-angle illumination lens 2k is set to be longer than the dimension in the optical axis direction of the wide-angle illumination lens 2j. Furthermore, the radial dimension at the base of the narrow-angle illumination lens 2k is set to be shorter than the radial dimension at the base of the wide-angle illumination lens 2j. The second illumination unit 2b is configured symmetrically with the first illumination unit 2a. In other words, in the longitudinal direction of the housing 60, the narrow-angle illumination lens 2k is located on the outside (farther from the imaging unit 3 located in the center), and the wide-angle illumination lens 2j is located on the inside. This makes the illumination distribution in the longitudinal direction of the housing 60 more uniform.

[0062] Since the first illumination unit 2a is stored on the right side of the housing 60, the first illumination unit 2a forms an irradiation surface (the surface of the light projection window 621) for irradiating the workpiece W with illumination light aligned along the first direction with the light receiving window 622. Furthermore, since the second illumination unit 2b is stored on the left side of the housing 60, the second illumination unit 2b also forms an irradiation surface (the surface of the light projection window 621) for irradiating the workpiece W with illumination light aligned along the first direction with the light receiving window 622.

[0063] 8, a first light-shielding member 67 that forms a first light-projection chamber R1 in which the first illumination unit 2a is stored, and a second light-shielding member 68 that forms a second light-projection chamber R2 in which the second illumination unit 2b is stored are provided within the housing 60. The first light-shielding member 67 is made of, for example, a resin material having light-shielding properties, and is stored on the right side of the housing 60 so as to surround the first illumination unit 2a. The second light-shielding member 68 is made of a material similar to the material that forms the first light-shielding member 67, and is stored on the left side of the housing 60 so as to surround the second illumination unit 2b.

[0064] The illumination light emitted from the first illumination unit 2a is blocked by the first light-shielding member 67, and therefore can be prevented from entering the lens 31a of the imaging unit 3. In addition, the illumination light emitted from the second illumination unit 2b is blocked by the second light-shielding member 68, and therefore can be prevented from entering the lens 31a of the imaging unit 3.

[0065] The housing 60 has a light-receiving room R3 that is configured from the portion of the housing 60 other than the first light-projecting room R1 and the second light-projecting room R2. That is, the light-receiving room R3 is configured by the space outside the first light-shielding member 67 and the second light-shielding member 68 in the housing 60, and therefore the light-receiving room R3 is a room that is optically isolated from the illumination units 2a and 2b.

[0066] The light-receiving chamber R3 houses the imaging unit 3 and the flat mirror 33. The imaging unit 3 is arranged on the rear side of the second illumination unit 2b inside the housing 60. The image sensor 31b is installed inside the housing 60 facing the longitudinal direction of the housing 60, which is the first direction. In this embodiment, the image sensor 31b is stored on the left side of the housing 60, so the light-receiving surface of the image sensor 31b faces right. Note that the imaging unit 3 may also be arranged on the rear side of the first illumination unit 2a inside the housing 60. In this case, the image sensor 31b should be arranged so that the light-receiving surface faces left.

[0067] Because the light receiving surface of image sensor 31b faces to the right, the optical axis of lens 31a faces in the left-right direction, with the side from which light enters lens 31a being the right side and the side from which light exits lens 31a being the left side. This lens 31a is also disposed at the back of second illumination unit 2b, and is positioned to the right of image sensor 31b.

[0068] The plane mirror 33 is a component within the housing 60 that folds the optical path corresponding to the field of view of the imaging unit 3 toward the light receiving window 622. Specifically, the plane mirror 33 is disposed between the first illumination unit 2a and the second illumination unit 2b. The plane mirror 33 extends in the vertical direction and is tilted with respect to the longitudinal direction of the housing 60 so that the closer it is to the front, the more to the right it is positioned. The tilted positioning of the plane mirror 33 makes it possible to fold the optical path corresponding to the field of view of the imaging unit 3 toward the light receiving window 622. In this embodiment, light reflected from the workpiece W passes through the light receiving window 622 and then enters the plane mirror 33. The light that enters the plane mirror 33 is configured to be emitted toward the lens 31a of the imaging unit 3.

[0069] 6 and 7, a polarizing filter attachment 652 is provided on the housing 60 so as to cover the light transmitting member 620. The polarizing filter attachment 652 is detachable from the housing 60 and can be used as needed. Figure 5 shows the state in which the polarizing filter attachment 652 has been removed.

[0070] The polarizing filter attachment 652 has a polarizing filter 652a having a polarizing film or the like provided to face the light transmitting member 620. A light blocking material 652b is provided between the polarizing filter 652a and the light transmitting member 620 to prevent the illumination light emitted from the first illumination unit 2a and the second illumination unit 2b from entering the optical system 31 of the imaging unit 3.

[0071] As shown in FIGS. 5 and 8 , the housing 60 is disposed facing the exterior of the housing 60, forms part of the light-receiving chamber R3, and has an indicator 69 that emits light based on the processing result of the decoding unit 44. The indicator 69 is controlled by the control unit 4 to emit light in a first color when the decoding result by the decoding unit 44 is normal, and emits light in a second color different from the first color when an error occurs. Because the indicator 69 forms part of the light-receiving chamber R3, there is a risk that some of the light from the indicator 69 may enter the light-receiving chamber R3. To address this issue, in this embodiment, the control unit 4 executes a light-off control to turn off the indicator 69 at least during exposure by the image capture unit 3. For example, by turning off the indicator 69 from the start to the end of exposure by the image capture unit 3, it is possible to prevent the light from the indicator 69 from affecting the image generated by the image capture unit 3.

[0072] A plurality of heat dissipation fins 640 extending in the left-right direction are provided on the third side surface 63 side of the lid-shaped case 610. Because the longitudinal direction of the light transmitting member 620 is the left-right direction, the longitudinal direction of the heat dissipation fins 640 coincides with the longitudinal direction of the light transmitting member 620. The plurality of heat dissipation fins 640 are formed at intervals from one another in the depth direction (width direction) of the housing 60. The heat dissipation fins 640 are made of the same material as the portion that constitutes the second side surface 62, and therefore have a high thermal conductivity.

[0073] 7, the housing 60 is provided with a cover 650 that covers the tips of the heat dissipation fins 640. By covering the tips of the heat dissipation fins 640 with the cover 650, an air passage extending along the longitudinal direction of the light-transmitting member 620 is formed between the third side surface 63 of the housing 60, the heat dissipation fins 640, and the cover 650.

[0074] The first code reader 1A is provided with a fan for blowing air in the longitudinal direction of the heat dissipation fins 640. The heat dissipation fins 640 are located in a portion where air is forcibly blown by the fan .

[0075] The heat dissipation fins 640 are discontinuous in the longitudinal direction of the heat dissipation fins 640. Specifically, cutout portions 640a are formed by cutting out portions of the heat dissipation fins 640 in the middle of the longitudinal direction. As a result, the heat dissipation fins 640 are provided discontinuously in the left-right direction, and therefore even if, for example, the left-right ends of the heat dissipation fins 640 come into close contact with some member and the air passage is blocked, the air blown into the air passage can escape to the outside through the cutout portions 640a, and a decrease in cooling efficiency can be suppressed.

[0076] 12 and 13, a through-hole 612 penetrating the lid-shaped case 610 in an inward and outward direction is provided in a portion of the lid-shaped case 610 where the fan 70 is disposed. A portion of the fan 70 attached to the lid-shaped case 610 protrudes into the housing 60 while being stored in the through-hole 612. This makes it possible to employ a large-diameter fan 70 while reducing the amount of downward protrusion of the fan 70, and as a result, the vertical dimension of the first code reader 1A can be shortened.

[0077] 12, the control board 90 on which the control unit 4 is mounted is attached to the lid-shaped case 610 via an attachment member 91. The attachment member 91 is, for example, a member that has the same thermal conductivity as the lid-shaped case 610. The control unit 4 is the part that decodes the code attached to the workpiece W based on the image generated by the image sensor 31b, and therefore its temperature rises during operation. The presence of the attachment member 91 allows the heat from the control board 90 to escape to the lid-shaped case 610 and be released by the heat dissipation fins 640.

[0078] 14 to 16 show a lens holder 300 that holds the lens 31a of the imaging unit 3. The lens holder 300 has a fixing portion 300a that is fixed to the lid-like case 610, and also has a tilt adjustment mechanism for the image sensor 31b. Specifically, a sensor board 301 as shown in FIG. 14 and a sensor holder 302 as shown in FIG. 15 are attached to the lens holder 300. The sensor board 301 is a member to which the image sensor 31b is fixed. The sensor board 301 is fixed to the sensor holder 302.

[0079] As shown in FIG. 16, with the sensor holder 302 removed, three springs 303 provided inside the lens holder 300 can be seen. The three springs (coil springs) 303 are arranged to surround an extension of the optical axis of the lens 31a. The plate-shaped sensor holder 302 is arranged to overlap the springs 303. Adjustment screws 304 are inserted into the portions of the sensor holder 302 that correspond to the springs 303. Each adjustment screw 304 is inserted into the spring 303 and screwed into the lens holder 300. The angle of the sensor holder 302 can be changed by tightening or loosening each adjustment screw 304. The image sensor 31b is fixed to the sensor holder 302 via the sensor board 301, so that the relative angle between the image sensor 31b and the lens 31a, i.e., the tilt, can be adjusted by changing the angle of the sensor holder 302. After adjustment, the components are attached to the lens holder 300 with adhesive so that they do not move relative to each other.

[0080] When the first code reader 1A is installed as shown in Figures 1 and 2, the bottom surface of the workpiece W being transported by the transport device B is exposed to the first code reader 1A side through the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2. The depth of field of the imaging unit 3 of the first code reader 1A is configured to include the bottom surface of the workpiece W exposed through the gap in the transport device B. This allows the imaging unit 3 to directly image the bottom surface of the workpiece W through the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2. "Directly" means that the imaging unit 3 images the bottom surface of the workpiece W without using a reflective member such as a mirror.

[0081] When installed as shown in Figures 1 and 2, the light receiving window 622 and the gap of the conveying device B are aligned, and in this state, the row direction of the image sensor 31b corresponds to the direction in which the gap of the conveying device B extends, and the column direction of the image sensor 31b corresponds to the conveying direction of the conveying device B (the direction indicated by arrow A in Figure 1).

[0082] Therefore, as shown in FIG. 17, the imaging unit 3 continuously captures images of the bottom surface of the workpiece W, which is exposed through the gap in the conveying device B and is included in the depth of field of the imaging unit 3, thereby outputting multiple images that capture a portion of the code attached to the bottom surface of the workpiece W. The upper side of FIG. 17 shows the upstream conveying mechanism B1 and downstream conveying mechanism B2 conveying the workpiece W as viewed from below, with the workpiece W being conveyed as shown from left to right. Because the dimension of the code in the conveying direction is longer than the gap between the upstream conveying mechanism B1 and downstream conveying mechanism B2, only a portion of the code in the conveying direction is exposed downward from the gap between the upstream conveying mechanism B1 and downstream conveying mechanism B2. As shown in the lower side of FIG. 17, multiple images capturing a portion of the code in the conveying direction are sequentially output from the imaging unit 3. The multiple images output from the imaging unit 3 are input to the control unit 4.

[0083] The control unit 4 is a part that generates a composite image based on the multiple images output from the imaging unit 3, and performs a decoding process on the code attached to the bottom surface of the workpiece W based on the composite image. As shown in Fig. 2, a specific configuration example of the control unit 4 can include, for example, a configuration example including a microcomputer having a processor (including a central processing unit), ROM, RAM, etc. An imaging control unit 41, an illumination control unit 42, a code detection unit 43, and a decoding unit (decoder) 44 are configured by the hardware included in the control unit 4 and the software executed by the control unit 4.

[0084] The code detection unit 43 of the control unit 4 identifies a code area based on the code image output from the imaging unit 3 and detects the code from the identified code area. The decoding unit 44 of the control unit 4 decodes the code detected by the code detection unit 43. Specifically, since the code is represented as black and white binary data, the decoding unit 44 decodes the black and white binary data. A table showing the correspondence between encoded data can be used for decoding. Furthermore, the decoding unit 44 checks whether the decoded result is correct using a predetermined check method. If an error is found in the data, the decoding unit 44 calculates the correct data using an error correction function. The error correction function differs depending on the type of code. The code detection unit 43 and decoding unit 44 of the first code reader 1A will be described in detail below, but the same applies to the second to fourth code readers 1B, 1C, and 1D.

[0085] The details of the processing by the control unit 4 will be described below based on the flowchart shown in Fig. 18. This flowchart starts when the operation of the first code reader 1A for the bottom surface is started. After the start, in step SA1, a read start trigger signal is input from the PLC 201 to the first code reader 1A. When the read start trigger signal is input, the illumination control unit 42 turns on the illumination unit 2, and the imaging control unit 41 causes the imaging unit 3 to capture an image and generate it.

[0086] In step SA2, the code detection unit 43 performs geometric correction as needed. For example, in an installation state in which a geometric change occurs according to the installation angle of the first code reader 1A, such as when the first code reader 1A is installed to the side of the conveying device B, each image will have a trapezoidal shape. In this case, in step SA2, keystone correction is performed on the trapezoidal shape of each image. As a result, an image similar to that obtained when the image is captured from directly below the workpiece W is obtained.

[0087] In step SA3, the code detection unit 43 combines the multiple processed images that have been geometrically corrected in step SA2 to generate a combined image that includes the code. In step SA4, it is determined whether the imaging unit 3 has taken a designated number of images. This number is set to the number of times that allows the entire code to be captured. If the determination in step SA4 is NO, the process proceeds to step SA1, where imaging, geometric correction, and image combination are repeated until the entire code is captured. If the determination in step SA4 is YES, the process proceeds to step SA5.

[0088] In step SA5, the code detection unit 43 generates multiple edge images by applying multiple edge extraction filters to the image synthesized in step SA3 to extract edges of different frequencies, and then integrates the multiple edge images.The code detection unit 43 determines code candidate positions based on the results of the edge integration process.That is, in the edge-processed image, it can estimate that an area where many pixels with high brightness values are concentrated is a code area.

[0089] For example, the code detection unit 43 can generate a heat map image that indicates the likelihood of a code in order to search for the position of a code within a code image. That is, the code detection unit 43 quantifies the feature values of the code, generates a heat map in which the magnitude of the feature values is assigned to each pixel value, and extracts code candidate areas on the heat map where there is a high probability that a code exists. As a specific example, there is a method of acquiring the feature portions of the code from areas that appear relatively hot (large feature values) in the heat map. When multiple feature portions are acquired, they can be prioritized and extracted, and stored in RAM, etc. Using the heat map image enables high-speed detection of code areas. The decoding unit 44 decodes the code searched for by the code detection unit 43.

[0090] 3, 6, and 8, the first code reader 1A includes a communication interface 80 for transmitting information relating to the result of the decoding process by the decoding unit 44. The communication interface 80 is a portion to which, for example, signal lines 200a, 201a, etc. are connected, and is provided at an end in the longitudinal direction of the housing 60. In this embodiment, the communication interface 80 is provided on the side where the imaging unit 3 is arranged, i.e., on the first end surface 65.

[0091] The signal lines 200a and 201a are connected to the communication interface 80 in the longitudinal direction of the housing 60. This prevents the signal lines 200a and 201a from protruding from the side surfaces 61 to 64 of the housing 60.

[0092] The first code reader 1A includes a bracket 810 as an attachment part for attaching the housing 60 to a frame 830. The bracket 810 is provided on a side of the housing 60 different from the light receiving window 622, i.e., on the third side surface 63. The side surface on which the light receiving window 622 is provided is the first side surface 61, and the first side surface 61 and the third side surface 63 are adjacent to each other. In other words, of the first to fourth side surfaces 61 to 64 that constitute the outer surface of the housing 60, the first side surface 61 (first side surface) including the light receiving window 622 and the irradiation surface 621 and the third side surface 63 (second side surface) on which the bracket 810 is provided are adjacent to each other.

[0093] The bracket 810 has a housing side member 811 fixed to the housing 60, a frame side member 812 fixed to the frame 830, and a connecting shaft 813 that rotatably connects the housing side member 811 and the frame side member 812. By rotating the housing side member 811 relative to the frame side member 812, the installation angle of the housing 60 can be freely adjusted, and it is also possible to change from the angle shown in Fig. 19 to the angle shown in Fig. 20, or vice versa. The housing side member 811 and the frame side member 812 can be fixed by a fastening member or the like so that they do not rotate relative to each other.

[0094] The housing 60 is formed with a guide surface 60a that serves as a guide during installation. The guide surface 60a is formed by chamfering a portion of the housing 60, and the angle of the guide surface 60a is set so that the reading surface and the reading surface are parallel to each other when the angle between the reading surface and the optical axis of the imaging unit 3 is 60°. Furthermore, when the angle between the reading surface and the optical axis of the imaging unit 3 is 60°, the surface (reference surface) on the reading surface side of the housing side member 811 is formed so as to be parallel to the reading surface, and the distance between the reading surface and the reference surface may be considered as the installation distance of the code reader 1A (particularly the imaging unit 3).

[0095] Here, it is assumed that multiple types of code readers with different reading distances (i.e., optical systems) will be developed to meet various user needs and applications. If the bracket 810 (housing side member 811) is designed so that when it is attached to the code reader 1, the positional relationship between the reference surface of the bracket 810 and the imaging unit 3 of the code reader 1 is substantially the same regardless of the type of code reader 1, the user can measure the installation distance based on the reference surface of the common bracket 810 regardless of the type of code reader 1, which simplifies installation by the user and eliminates the need for an individual bracket 810 for each type of code reader 1.

[0096] 21 shows the housing 60 as seen from the front. As shown in this figure, the bracket 810 is provided with a retaining portion 814 for retaining the signal line 201a. By providing the retaining portion 814, it becomes possible to position the signal line 201a at a predetermined position. The retaining portion 814 is formed, for example, by a protrusion or the like.

[0097] 22 is a bottom view of the housing side member 811 fixed to the housing 60. The housing side member 811 has an attachment hole 815 for attachment to the housing 60, and by using this attachment hole 815, the housing side member 811 can be fixed to the housing 60 with a screw (not shown). The housing side member 811 also has a field of view center marker 816 for indicating the center of the field of view. When installing the housing side member 811, the center of the field of view can be easily determined by looking at the field of view center marker 816 and aligning it with the frame side member 812.

[0098] FIG. 23 is a side view showing an example of installation in which the optical axis of the imaging unit 3 is perpendicular to the reference plane. As shown in this figure, the installation angle of the housing 60 can be adjusted to make the optical axis of the imaging unit 3 perpendicular to the reference plane. FIG. 24 shows an example of installation in which a mirror is used, and the housing 60 can also be installed so that a mirror 880 is interposed between the imaging unit 3 and the workpiece W. When the mirror 880 is interposed, light reflected from the cord is reflected by the mirror 880 and enters the imaging unit 3. Furthermore, illumination light emitted from the illumination unit 2 is reflected by the mirror 880 and reaches the workpiece W to which the cord is attached. By interposing the mirror 880, the flexibility of installation of the housing 650 is improved.

[0099] FIG. 25 shows an example of installation in which the mounting surface of the bracket 810 is changed. The left side of FIG. 25 shows the case where the bracket 810 is mounted on the third side surface 63 of the housing 60, and the right side of FIG. 25 shows the case where the bracket 810 is mounted on the fourth side surface 64 of the housing 60. As shown in FIG. 25, by mounting the bracket 810 on the third side surface 63 of the housing 60, the height of the frame 830 from the reference plane becomes a first height H1, which can be lower than the case where the bracket 810 is mounted on the fourth side surface 64 (second height H2). Therefore, for example, by applying this mounting structure to the code readers 1A to 1D shown in FIGS. 1 and 2, the amount of protrusion of the code readers 1A to 1D from the members 831 to 833 of the frame 830 toward the conveyance device B is reduced, thereby improving the degree of freedom in installation.

[0100] (Another embodiment) The embodiments of the present invention are not limited to the above-described embodiment, and may be, for example, other embodiments as described below. In the following description of the other embodiments, the same components as those in the above-described embodiment are denoted by the same reference numerals and description thereof will be omitted, and differences will be described in detail. Furthermore, by combining the above-described embodiment with the following other embodiments, it is possible to obtain yet another embodiment. When combining the above-described embodiment with the following other embodiments, it is also possible to combine a position of the above-described embodiment with a part of the following other embodiments.

[0101] In the first example shown in FIG. 26, the imaging unit 30 of the fourth code reader 1D has a first imaging unit 30a and a second imaging unit 30b. The first to third code readers 1A, 1B, and 1C can be configured similarly. The first imaging unit 30a and the second imaging unit 30b are stored separately on the left and right sides. The first imaging unit 30a is stored on the left side of the housing 650, and the second imaging unit 30b is stored on the right side of the housing 650. A first mirror 881 and a second mirror 882 are stored in the center of the housing 650 in the horizontal direction. The first mirror 881 is a component for allowing reflected light from the code to enter the first imaging unit 30a. The second mirror 882 is a component for allowing reflected light from the code to enter the second imaging unit 30b.

[0102] The first imaging unit 30a includes a first image sensor 30c and a first optical system 30d. The first image sensor 30c has a two-dimensional light-receiving surface for forming a predetermined field of view and is a component that generates an image corresponding to an image projected onto the light-receiving surface through a light-receiving window 622. The first optical system 30d is interposed between the light-receiving window 622 and the light-receiving surface of the first image sensor 30c and is a component that projects an image corresponding to a code attached to the workpiece W inside the housing 60 onto the light-receiving surface of the first image sensor 30c. The first optical system 30d forms an optical path that is long along the longitudinal direction of the light-receiving window 622 and whose optical axis passing through the center of the field of view is inclined with respect to the longitudinal direction. The field of view and depth of the first imaging unit 30a can be set by various parameters of the first optical system 30d.

[0103] The second imaging unit 30b includes a second image sensor 30e and a second optical system 30f. The second image sensor 30e has a two-dimensional light-receiving surface for forming a predetermined field of view and generates an image corresponding to an image projected onto the light-receiving surface through the light-receiving window 622. The second optical system 30f is interposed between the light-receiving window 622 and the light-receiving surface of the second image sensor 30e and projects an image corresponding to a code attached to the workpiece W inside the housing 60 onto the light-receiving surface of the second image sensor 30e. The second optical system 30f forms an optical path that is long along the longitudinal direction of the light-receiving window 622 and whose optical axis passing through the center of the field of view is inclined relative to the longitudinal direction. The field of view and depth of the second imaging unit 30b can be set by various parameters of the second optical system 30f. The optical axis of the first imaging unit 30a and the optical axis of the second imaging unit 30b are closely related.

[0104] The field of view and depth of the first imaging unit 30a are different from the field of view and depth of the second imaging unit 30b. Specifically, the field of view and depth of the first imaging unit 30a are within the range enclosed by the dashed frame indicated by reference symbol 8A in FIG. 27 (referred to as the first range). Various parameters of the first optical system 30d are set so as to fall within the first range 8A. On the other hand, the field of view and depth of the second imaging unit 30b are within the range enclosed by the solid frame indicated by reference symbol 8B in FIG. 27 (referred to as the second range). Various parameters of the second optical system 30f are set so as to fall within the second range 8B.

[0105] The first range 8A is set to include an area farther away than the second range 8B, and the farthest field of view A1 of the first range 8A is wider than the farthest field of view A2 of the second range 8B. The second range 8B is set to include an area closer than the first range 8A. The provision of the first image sensor 30c and the second image sensor 30e expands the field of view and depth of the imaging unit 30. In other words, the imaging unit 30 includes the first image sensor 30c and the second image sensor 30e for expanding the field of view and depth in the depth direction perpendicular to the plane forming the light receiving window 622 in the imaging field of view. A third imaging unit may be provided in addition to the first imaging unit 30a and the second imaging unit 30b. In this case, the first imaging unit 30a, the second imaging unit 30b, and the third imaging unit may be configured to have different fields of view and depths.

[0106] The first imaging unit 30a can be referred to as a far-distance imaging unit because it is an imaging unit capable of imaging a farther side than the second imaging unit 30b. Conversely, the second imaging unit 30b can be referred to as a near-distance imaging unit because it is an imaging unit capable of imaging a nearer side than the first imaging unit 30a. In this way, the imaging unit 30 includes a near-distance imaging unit that images the near side and a far-distance imaging unit that images the far side. When a third imaging unit is provided, the third imaging unit can be, for example, a near-distance imaging unit.

[0107] The first code reader 1A further includes a light-amount reducing member 30g (shown in FIG. 26) that reduces the amount of light incident on the second image sensor 30e of the second imaging unit 30b, which is a near-distance imaging unit, thereby reducing the difference in light amount between the second image sensor 30e and the first image sensor 30c of the first imaging unit 30a, which is a far-distance imaging unit. This reduces the difference in brightness between the images obtained by each imaging unit, eliminating the need for parameter switching due to differences in brightness values in subsequent image processing, thereby reducing the processing load. The light-amount reducing member 30g is composed of a neutral density filter (e.g., an ND filter) provided in the second optical system 30f of the second imaging unit 30b. The amount of light attenuation by the neutral density filter can be set as desired. The light-amount reducing member 30g may be provided as needed or may be omitted.

[0108] FIG. 28 shows a second example. This example is the same as the first example in that the imaging unit 30 includes a first imaging unit 30a and a second imaging unit 30b. However, the field of view and depth of the first image sensor 30c and the second image sensor 30e are different from those of the first example. Furthermore, the optical axis of the first imaging unit 30a and the optical axis of the second imaging unit 30b are positioned farther apart than in the first example. That is, in the second example, the first range 8A is positioned below the second range 8B and is configured to include an area farther than the second range 8B. The field of view and depth of the imaging unit 30 are expanded by the farthest field of view A1 of the first range 8A and the farthest field of view A2 of the second range 8B. In the second example, the optical paths of the first imaging unit 30a and the second imaging unit 30b do not coincide. Therefore, a portion of the light receiving window 622 corresponds to the optical path of the first imaging unit 30a, and another portion corresponds to the optical path of the second imaging unit 30b. In this case, the light amount reducing member 30g can be configured as a neutral density filter provided in a portion of the light receiving window 622 corresponding to the optical path of the second imaging unit 30b. This makes it possible to reduce the difference in light amount between the amount of light incident on the second image sensor 30e of the second imaging unit 30b and the amount of light incident on the first image sensor 30c of the first imaging unit 30a. In the second example, a neutral density filter may also be provided in the second optical system 30f, as in the first example.

[0109] FIG. 29 is a diagram showing a third example in which the first imaging unit 30a and the second imaging unit 30b are stored on the left side of the housing 60. In this third example, a mirror 883 is stored in the center of the housing 60 in the left-right direction. The mirror 883 is a member for directing reflected light from the cord into the first imaging unit 30a and the second imaging unit 30b. In this example as well, by providing the first imaging unit 30a and the second imaging unit 30b, the field of view and depth can be expanded as described above. Note that the first imaging unit 30a and the second imaging unit 30b may also be stored on the right side of the housing 650.

[0110] 30 is a diagram showing a fourth example in which the first imaging unit 30a and the second imaging unit 30b are stored in the center in the left-right direction of the housing 60. In this fourth example, reflected light from the cord passes through the light receiving window 622 and then enters the first imaging unit 30a and the second imaging unit 30b.

[0111] FIG. 31 is a diagram illustrating a case where a variable-focus lens capable of adjusting focus is used as the lens 31a of the imaging unit 3. By using a variable-focus lens, the depth of the imaging unit 3 can be changed in multiple stages. In this example, the depth of the imaging unit 3 is changed in three stages: a first range 8A focused on a distant object, a second range 8B focused on a near object, and a third range 8C focused on a medium distance. This allows the field of view and depth to be expanded without increasing the number of imaging units 3. The depth of the imaging unit 3 may be changed in two stages, or in multiple stages of four or more stages. Variable-focus lenses include, for example, mechanically movable lenses and liquid lenses.

[0112] The above-described multiple alternative embodiments may each be an independent form, but it is also possible to combine any multiple alternative embodiments together to form an embodiment.

[0113] Furthermore, the present invention is not limited to code readers. For example, part of the present invention can be applied to a system equipped with a control unit that does not perform code decoding. In this case, the system functions as an image processing device that processes images acquired by capturing images of the workpiece W being transported by the transport device B, and the control unit performs various types of image processing. Examples of various types of image processing include OCR processing and image inspection processing.

[0114] The above-described embodiments are merely examples in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0115] As described above, the code reader according to the present disclosure can be used, for example, to read a code attached to a workpiece. [Explanation of symbols]

[0116] 1A, 1B, 1C, 1D Code Reader 2. Lighting section 3. Imaging unit 4. Control section 31 Scheimpflug optics 31a lens 31b Image sensor 33 Plane mirror 44 Decoder 60 cabinets 80 Communication Interface 620 Light-transmitting material 621 Floodlight 622 Light receiving window 810 Bracket (mounting part) 830 frames B. Conveyor device double work

Claims

1. A stationary code reader configured to be usable in a state attached to an external frame and to read a code attached to a workpiece transported by a transport device, a housing having a light receiving window that is long along a first direction and transmits light laterally; an illumination unit that is housed in the housing and forms an illumination surface for irradiating illumination light onto a workpiece, the illumination surface being aligned with the light receiving window along the first direction; an imaging unit including an image sensor having a two-dimensional light receiving surface and installed in the housing facing the first direction, and a lens in the housing that projects an image corresponding to the code attached to the workpiece onto the light receiving surface of the image sensor; a mirror disposed within the housing, the mirror bending an optical path corresponding to a field of view of the imaging unit toward the light receiving window; a decoder that performs a decoding process of the code attached to the work based on the image generated by the imaging unit; a mounting portion provided on a side of the housing different from the light receiving window, for mounting the housing to the external frame.

2. 2. The code reader according to claim 1, The code reader further comprises a communication interface provided at an end of the housing in the first direction, for transmitting information relating to a result of the decoding process by the decoder.

3. 2. The code reader according to claim 1, A code reader, wherein, among a plurality of side surfaces constituting the outer surface of the housing, a first side surface including the light receiving window and the irradiation surface and a second side surface on which the mounting portion is provided are adjacent to each other.

4. 2. The code reader according to claim 1, the light receiving surface is inclined with respect to the optical axis of the lens, The lens and the image sensor constitute a Scheimpflug optical system.

5. 2. The code reader according to claim 1, A code reader, wherein the imaging unit has the lens or a plurality of the image sensors for expanding the field of view or depth in a depth direction perpendicular to a plane that forms the light receiving window in the field of view.

6. 2. The code reader according to claim 1, the imaging unit includes a near imaging unit that images a near side and a far imaging unit that images a far side, a light amount reduction member that reduces the amount of light incident on the image sensor of the near-distance imaging unit, thereby reducing the difference in light amount between the amount of light incident on the image sensor of the far-distance imaging unit and the amount of light incident on the image sensor of the near-distance imaging unit.

7. 7. The code reader according to claim 6, The light amount reducing member is configured as a light-reducing filter provided in the optical system of the near-distance imaging unit.

8. 7. The code reader according to claim 6, The light amount reducing member is configured as a light-reducing filter provided in a portion of the light receiving window corresponding to the optical path of the near-distance imaging section.

9. 2. The code reader according to claim 1, The code reader, wherein the illumination section includes a first illumination section and a second illumination section spaced apart from each other in the first direction.

10. 10. The code reader according to claim 9, The code reader, wherein the mirror is disposed between the first illumination unit and the second illumination unit.

11. The code reader according to claim 10, The code reader, wherein the imaging unit is disposed on the rear side of the first illumination unit or the rear side of the second illumination unit within the housing.

12. 2. The code reader according to claim 1, the illumination unit includes a first illumination angle illumination unit whose illumination light spreads at a first illumination angle, and a second illumination angle illumination unit whose illumination light spreads at a second illumination angle that is wider than the first illumination angle, and the first illumination angle illumination unit and the second illumination angle illumination unit are aligned in the first direction.

13. 2. The code reader according to claim 1, a light-projecting window that transmits illumination light emitted from the illumination unit to the outside of the housing, and the light-receiving window are formed from a common light-transmitting member.

14. The code reader according to claim 13, the light transmitting member is formed to be long in the first direction, a window frame member for fixing the light transmitting member to the housing; The code reader further comprises a packing interposed between the window frame member and the light transmitting member.

15. 2. The code reader according to claim 1, A code reader, wherein a light blocking member is provided inside the housing to prevent illumination light emitted from the illumination unit from entering the lens of the imaging unit.

16. 2. The code reader according to claim 1, At least a portion of the housing is formed by a first housing component made of metal having heat dissipation fins extending in a predetermined direction, A code reader, wherein a control board on which the decoder is provided is attached to the first housing component via a member having thermal conductivity.

17. 17. The code reader according to claim 16, the heat dissipation fins extend along the first direction, The cord reader further includes a fan that blows air in the longitudinal direction of the heat dissipation fins.

18. 17. The code reader according to claim 16, a part of the housing is formed by the first housing component, the other part of the housing is made of a second housing component made of resin, The code reader, wherein the first housing component and the second housing component are integrated.

19. 2. The code reader according to claim 1, The housing includes: a light receiving room that houses the imaging unit and the mirror and is isolated from the lighting unit; an indicator that forms part of the receiving chamber and emits light based on the processing result of the decoder; the code reader further includes a control unit that controls the imaging unit, the decoder, and the indicator; The control unit executes a turn-off control to turn off the indicator at least during exposure by the imaging unit.

20. A stationary image processing device configured to be usable in a state attached to an external frame, which processes an image obtained by capturing an image of a workpiece transported by a transport device, a housing having a light receiving window that is long along a first direction and transmits light laterally; an illumination unit that is housed in the housing and has an illumination surface for irradiating illumination light onto a workpiece that is arranged side by side with the light-receiving window along the first direction; an imaging unit having an image sensor having a two-dimensional light receiving surface and installed in the housing facing the first direction, and a lens that projects an image corresponding to a workpiece onto the light receiving surface of the image sensor in the housing; a mirror disposed within the housing, the mirror bending an optical path corresponding to a field of view of the imaging unit toward the light receiving window; a control unit that executes image processing based on the image generated by the imaging unit; an attachment portion provided on a side of the housing for attaching the housing to the external frame.

Images