JP6486767B2 - Fixed optical information reader and optical information reading method using the same - Google Patents

Description

  The present invention relates to a fixed optical information reading device among optical information reading devices that optically read information.

  The optical information reading device includes a handy type optical information reading device in which an operator reads a code by hand, and a fixed optical information reading device that fixes the device and moves an object to which the code is attached. . The fixed optical information reader is mainly installed in a factory line and reads a code stamped or affixed on a work (product to be inspected) conveyed by a conveyor belt. In particular, two-dimensional code readers (hereinafter referred to as readers) that read two-dimensional codes such as barcodes and QR codes (registered trademark) are widely used. An example of such a reader is described in Patent Document 1.

JP 2011-76519 A

  By the way, if the reader is downsized, the optical axis of the image sensor and the optical axis of the illumination system must be parallel. This is because the distance between the optical axis of the image sensor and the optical axis of the illumination system must be shortened. In such a reader, illumination light is reflected on the surface of the workpiece, and regular reflection light (specular reflection light) is incident on the image sensor, making it difficult to read the two-dimensional code. In particular, in a mirror-finished metal workpiece or the like, specular reflection occurs on the surface of the workpiece, and the specular reflection light enters the image sensor, making it impossible to read the code. Therefore, the reader must be installed with the optical axis tilted with respect to the normal so that the normal of the workpiece surface does not coincide with the optical axis of the reader. This is called diagonal mounting. Note that attaching the reader so that the normal of the surface of the workpiece and the optical axis of the reader are parallel will be referred to as front attachment.

  By performing oblique mounting, the specular reflected light travels in the direction in which the image sensor does not exist, but is reflected by an object existing around the reader, returns to the surface of the work, and is reflected again by the surface of the work, and the image sensor May enter. In order to avoid this, it is difficult for the user to further adjust the attachment angle (skew angle) of the reader. SUMMARY OF THE INVENTION An object of the present invention is to provide an optical information reader capable of accurately reading a code attached to a workpiece that causes specular reflection.

According to the present invention, for example,
A housing,
An illuminating means including a first illuminating unit and a second illuminating unit that emit light from the light emitting region on the first surface side of the housing;
Light incident on the first surface side of the housing having an optical axis parallel to the light emission direction of the first illumination unit and the light emission direction of the second illumination unit, which is different from the light emission region Imaging means for imaging a code provided on the workpiece by receiving light reflected from the workpiece, which is light incident from a region;
Decoding means for decoding the code imaged by the imaging means;
An attachment hood that is detachable from the housing and surrounds the light emitting region and the light incident region;
Have
The attachment hood is
An imaging lens disposed on the optical axis of the imaging means and forming an image of the code on the imaging means;
Provided on the emission axis of light emitted from the first illumination unit and on the emission axis of light emitted from the second illumination unit, and emitted from the first illumination unit and the second illumination unit have a diffusion means for diffusing light,
The first illumination unit is provided near an end in a longitudinal direction of the first surface of the housing,
The second illuminating unit is provided apart from the longitudinal end of the first surface of the casing, and a fixed optical information reader is provided. .

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the optical information reader which can read the code provided to the workpiece | work which raise | generates a specular reflection accurately.

The figure which shows an optical information reader The figure which shows the structure of an optical information reader The figure which shows the support structure of an image display apparatus The figure which shows the display and operation panel of an optical information reader The figure which shows the electrical structure of an optical information reader. The figure which shows the computer connected to an optical information reader The figure which shows an example of the shape of a polarizing filter The figure which shows an example of the shape of a polarizing filter The figure explaining the reading image according to the difference in the skew angle of a reader Illustration explaining attachment hood Exploded view for explaining the members constituting the attachment hood The figure explaining the reading image according to the difference in the skew angle of a reader The figure explaining the guide member which guides the recommended angle of a skew angle Diagram explaining bright field illumination mode and dark field illumination mode Flow chart showing lighting mode tuning processing The figure explaining the relationship between a skew angle and the presence or absence of a diffusing member The figure explaining the change of the read image of the code according to the difference in the diffusion degree of a diffusion member

  An embodiment of the present invention is shown below. The individual embodiments described below will help to understand various concepts, such as the superordinate concept, intermediate concept and subordinate concept of the present invention. Further, the technical scope of the present invention is determined by the scope of the claims, and is not limited by the following individual embodiments.

  FIG. 1 is a diagram showing an example of a reader system (optical information reader). A line 1 is a conveyance belt that conveys a workpiece 2 that is an inspection object. The reader 3 is a two-dimensional code reader that reads and decodes a two-dimensional code. Note that the reader 3 itself is an optical information reading device in a narrow sense. The programmable logic controller (PLC 5) is a control device that controls the line 1 and the reader 3. The computer 4 is an information processing apparatus that sets operating conditions and the like for the reader 3 and acquires and displays a decoding result from the reader 3.

<Structure of reader 3>
2A is a perspective view of the reader 3, and FIG. 2B is a development view of main components. Since the shape of the reader 3 is a substantially rectangular parallelepiped, the outer surface of the housing has approximately six surfaces. That is, the housing 9 has a top surface 94, a bottom surface 95, a front surface 96, a rear surface 97, a left side surface 98, and a right side surface 99. As shown in FIG. 2B, the housing 9 is mainly composed of a front case 10 and a rear case 19.

  As shown in FIG. 2B, the front case 10 is provided with four openings. The opening on the top surface side is provided with a holder 13, an image display device 14 supported by the holder 13, a display panel 15 arranged so as to cover the image display device 14, and a main sheet 16. An opening on the front side of the front case 10 is provided with a light-transmitting window 11 and a front cover 12. A polarizing filter may be provided in a part of the window portion 11. A portion of the front surface 96 below the front cover 12 is referred to as an abdomen. In this example, the center of the abdomen has a substantially rectangular flat surface portion and curved surface portions located on the left and right sides thereof. The reflector 17 and the illumination board 18 are inserted from the opening on the rear surface side of the front case 10 and are covered by the rear case 19. The rear case 19 is provided with a main board 21, an optical system 50 fixed to the main board 21, and an AF mechanism 51. The reflector 17 is a structural component for efficiently irradiating the light from the light emitting element provided on the illumination substrate 18 forward. The reflector 17 has cone-shaped condensing units 176 to 179 for condensing and irradiating the light from the light emitting element for illumination forward, and the light from the light emitting element for the pointer forward. A cone-shaped condensing part 175 for condensing and irradiating is provided. These are plated with gold or the like to increase the light collection efficiency. A connector holder 20 is attached to the opening on the bottom side of the front case 10. Two communication cables are connected to the connector holder 20, and are connected to the computer 4 and the PLC 5, respectively. A connector substrate is attached to the connector holder 20.

  The left side surface 98 and the right side surface 99 may be provided with screw holes 45 for fixing optional attachment parts detachable from the reader 3. A diffusion member or the like to be described later may be screwed using this screw hole 45.

  FIGS. 3A to 3C are views for explaining the structure around the holder 13. As shown in FIGS. 2A, 3A, and 3B, the holder 13 is a support member that supports the image display device. The illumination board 18 extends in a direction perpendicular to the holder 13 and engages the holder 13 to support the holder 13. That is, the holder 13 is provided in parallel with the top surface 94 of the front case 10, and the illumination board 18 is provided in parallel with the front surface 96 of the front case 10, and both are orthogonal to each other. A groove 131 is provided on the bottom side of the holder 13, and the holder 13 may be firmly fixed to the illumination substrate 18 by fitting the end of the illumination substrate 18 into the groove 131. By adopting such a holder 13, a circuit board to which the image display device 14 is attached can be eliminated.

  As shown in FIGS. 3A and 3C, the illumination board 18 is provided with push button type switches 24 and 25 having a pressing surface on the same side as the display surface of the image display device 14. May be. The switches 24 and 25 may be pressed by the pressing members 22 and 23 formed integrally with the holder 13 so that the respective contacts are closed. Since the pressing direction of the switches 24 and 25 coincides with the length direction of the illumination board 18 indicating the holder 13, the holder 13 is not easily bent even when the switches 24 and 25 are pressed. The pressing member 22 is supported by an elastic arm portion 39 a extending from the main body of the holder 13. Similarly, the pressing member 23 is supported by an elastic arm portion 39 b extending from the main body of the holder 13. The pressed pressing members 22 and 23 are returned to their original positions by the elasticity of the arm portions 39a and 39b. Since the arm portions 39a and 39b are integrally formed with the holder 13, there is an advantage that an additional member for return such as a spring can be omitted.

  As shown in FIGS. 3A and 3B, the illumination substrate 18 has a circular shape for mounting an optical system module (such as the optical system 50 and the AF mechanism 51) provided corresponding to the imaging element 31. The opening 33 is provided. Around the opening 33, four light emitting elements 26 to 29 for illumination are provided. As shown in FIG. 3A, one or a plurality of light emitting elements 32 functioning as indicators are provided in the vicinity of the engaging portion between the illumination board 18 and the holder 13. A light guide opening 34 is provided in the holder 13 so that light from the light emitting element 32 is output from the top surface 94 of the front case 10 to the outside. That is, an indicator is disposed between the two switches 24 and 25. As shown in FIG. 3C, since the four sides of the opening 34 are surrounded by the light shielding walls 36a to 36d, the light from the indicator is less likely to leak toward the image display device 14. The holder 13 is provided with an accommodation groove 37 for accommodating the image display device 14. Further, a hole 38 for passing a signal cable of the image display device 14 is provided at the bottom of the accommodation groove 37.

  As shown in FIG. 3B, an image sensor 31 is arranged on the main board 21. As shown in FIG. 3B, the illumination board 18 is provided with a light emitting element 35 that outputs pointer light. As described above, the reflector 17 is provided with the light collecting portions 176 to 179 for the light emitting elements 26 to 29 in addition to the light collecting portion 175 for the light emitting element 35. The condensing parts 175 to 179 have a cone shape, and light enters from the opening on the top side of the cone and exits from the bottom side.

  FIG. 4 is a view showing the main seat 16. A display surface 40 of the image display device 14 is provided at the center of the main sheet 16. A select key 42, an indicator 44, and an enter key 43 are provided below the main sheet 16. The select key 42 includes the switch 24 and the pressing member 22 described above. The enter key 43 includes the switch 25 and the pressing member 23 described above. The indicator 44 is composed of two light emitting elements 32. For example, when the two-dimensional code is successfully read, the green light-emitting element is turned on, and when the two-dimensional code reading is unsuccessful, the red light-emitting element is turned on. In addition to the image (still image or moving image) acquired by the image pickup device 31, the image display device 14 displays an image (SEL and MENU in FIG. May be displayed))).

<Control unit>
FIG. 5 is a block diagram showing an electronic configuration of the reader 3. The camera unit (imaging unit) of the reader 3 includes an imaging element 31, an optical system 50, an AF mechanism 51, an illumination unit 52, and the like. The image sensor 31 is an image sensor such as a CCD or CMOS that converts an image of a two-dimensional code formed through the optical system 50 into an electrical signal. The AF mechanism 51 is a mechanism that adjusts the position and refractive index of the focusing lens in the optical system 50. The AF mechanism 51 and the optical system 50 are disposed between the image sensor 31 and the opening 33 in FIG. The AF mechanism 51 and the optical system 50 may be integrated to form an optical system module.

  The illumination unit 52 has one or more light emitting elements and is a unit that illuminates a two-dimensional code. The illumination part 52 has the light emitting elements 26-29 for illumination and the light emitting element 35 for pointers, for example. The light from the pointer serves as a guide for the optical axis of the optical system 50, and the user may refer to the position of the pointer and place the workpiece 2 at the correct position.

  The decoding unit 53 is a unit that decodes the image data 72 of the two-dimensional code acquired by the image sensor 31 and writes the decoding result 71 in the storage unit 70. The communication unit 54 is a unit that communicates with the PLC 5 and the computer 4. The communication unit 54 may include, for example, an I / O unit that communicates with the PLC 5, a serial communication unit such as RS232C, a network communication unit such as a wireless LAN or a wired LAN, and the like.

  The display unit 55 includes the image display device 14 and the indicator light emitting element 32. The display unit 55 includes, for example, a character string that is the decoding result 71 of the two-dimensional code, a reading success rate (average reading success rate when the reading process is executed a plurality of times), and a matching level (reading margin indicating ease of reading). Degree), PPC (a value indicating how many pixels a single cell constituting the two-dimensional code corresponds to: pixel per cell), and the like may be displayed. The input unit 56 is a unit that accepts an input operation such as a switch, and includes a select key 42 and an enter key 43.

  The control unit 60 is a unit that comprehensively controls each unit of the reader 3. The control unit 60 has various functions, but these may be realized by a logic circuit or may be realized by executing sohood air. An autofocus control unit (AF control unit) 61 is a unit that controls the AF mechanism 51. The imaging control unit 62 is a unit that controls the amount of illumination light of the illumination unit 52 and controls the exposure time (shutter speed) of the imaging device 31. In particular, the imaging control unit 62 functions as a lighting control unit that controls which of the plurality of light emitting elements of the lighting unit 52 is turned on in response to an instruction from the tuning unit 65 or the calculation unit 63.

  The calculation unit 63 executes various calculation processes. For example, the calculation unit 63 calculates a reading success rate, a matching level, and a PPC by using a decoding result and image data. Of course, these calculations may be executed by units other than the calculation unit 63 such as the decoding unit 53 and the tuning unit 65.

  The tuning unit 65 functions as a reading condition control unit that controls reading conditions or a condition determination unit that determines illumination conditions. The reading conditions are, for example, imaging conditions such as exposure time, illumination light quantity, gain, and image processing conditions (such as filter coefficients) in the decoding unit 53. Appropriate imaging conditions and image processing conditions change due to the influence of external light on the workpiece 2 conveyed on the line 1. Therefore, the tuning unit 65 searches for a more appropriate reading condition and sets the AF control unit 61, the imaging control unit 62, and the decoding unit 53. The tuning unit 65 may determine which one of the dark field illumination mode and the bright field illumination mode is suitable for reading the code.

  The UI management unit 66 is a unit that displays image data on the image display device 14, receives a user instruction from the input unit 56, and controls lighting of the indicator.

  The storage unit 70 is a storage device such as a memory. The decoding result 71 acquired by the decoding unit 53, the image data 72 acquired by the image sensor 31, the data set in the reader 3 by the setting device such as the computer 4, The setting data 73 that is data set by the input unit 56 is stored.

  FIG. 6 is a block diagram showing functions of the computer 4. If the size of the reader 3 is reduced, it becomes difficult to set all the functions of the reader 3 with only the display unit 55 and the input unit 56 of the reader 3. Therefore, some setting data 73 may be created by the computer 4 and transferred to the reader 3. The CPU 80 is a unit that controls each unit included in the computer 4 based on a program stored in the storage unit 90. The UI control unit 83, which is one function of the calculation unit 81, generates a user interface for setting the imaging conditions of the reader 3, and a user interface for displaying the decoding result 71, the image data 72, and the like output from the reader 3. Are displayed on the display unit 84. The calculation unit 81 is a unit that executes various calculations. The communication unit 86 is wired or wirelessly connected to the communication unit 54 of the reader 3 and receives the decoding result 71 and the image data 72 and transmits the setting data 73 generated by the setting unit 82. The storage unit 90 is a memory, a hard disk drive (HDD), a solid state drive (SSD), or the like.

<Polarizing filter>
In the present embodiment, a first illuminating unit provided with a polarizing filter and a second illuminating unit not provided with a polarizing filter are provided, and one of them is selected according to the work 2 and lit. It is optional to provide a polarizing filter.

  FIG. 7A is a perspective view of the reader 3, and FIG. 7B is an enlarged view of the window portion 11. In the window portion 11, a polarizing filter 91 is provided in a portion where the light from the light emitting element 26 is emitted (light emitting region) and a portion where the light from the light emitting element 27 is emitted. In addition, a polarizing filter 92 is provided in a portion (light incident region) where light enters the optical system of the image sensor 31 in the window portion 11. In the window portion 11, a light emission area where light from the light emitting elements 26 to 29 is emitted is referred to as a first area, and a light incident area where light is incident on the optical system of the imaging element 31 is referred to as a second area. Note that the polarization direction of the polarization filter 91 and the deflection direction of the polarization filter 92 are different, for example, 90 degrees. On the other hand, the polarizing filter is not provided in the part from which the light of the light emitting element 28 radiates | emits, and the part from which the light of the light emitting element 29 radiates | emits among the window parts 11. FIG. As described above, the light emitting element 26 and the light emitting element 27 may form the first illumination unit, and the light emitting element 28 and the light emitting element 29 may form the second illumination unit. That is, instead of the user performing installation or removal of the polarization filter, it is only necessary to electrically switch which illumination means the reader 3 turns on. For example, for a work (for example, casting) which is more advantageous without a polarizing filter, the second illumination unit is turned on and the first illumination unit is turned off. On the other hand, for a work that is more advantageous with a polarizing filter (for example, a work having a two-dimensional code on a printed circuit board, a milled surface, a black resin, etc.), the first illumination means is turned on and the second illumination means is Turn off the light. As a result, the burden on the user can be greatly reduced, and two-dimensional codes provided on various workpieces can be accurately read with one reader 3.

  FIG. 8A shows an example of the shape of the polarizing filter 91 and the polarizing filter 92. In particular, the polarizing filter 92 for the image sensor has a substantially circular shape, and alignment members 93 a and 93 b are provided on the left end and the right end of the polarizing filter 92, respectively. The left end and the right end of the bottom of the polarizing filter 91 are aligned with the shapes of the alignment members 93a and 93b, and in this example, are linear. The center of the bottom of the polarizing filter 91 is substantially semicircular and matches the shape of the upper part of the polarizing filter 92. As described above, by using the alignment members 93a and 93b, the polarizing filter 91 and the polarizing filter 92 are easily attached to the window portion 11 accurately. Moreover, since the shape of the top part of the polarizing filter 91 is matched with the shape of the top part of the window part 11, it is easy to attach the polarizing filter 91 with respect to the window part 11 accurately.

<Advantages of diagonal mounting>
The advantage of attaching the diffuse reflection member to the reader 3 will be described with reference to FIGS. 9 (A) to 9 (F). FIG. 9A is a side view when the reader 3 is attached to the work 2 in front. The workpiece 2 has a metal surface, and a cord 6 is provided on the metal surface by DPM. DPM is an abbreviation for direct parts marking. DPM is a method of marking a code on a metal surface or the like by irradiating laser light, for example. As shown in FIG. 9A, the light emitted from the light emitting elements 26 and 27 is specularly reflected (regularly reflected) by the metal surface or the cord 6 and enters the imaging element 31. FIG. 9B shows an example of an image captured by the image sensor 31 during front mounting. As shown in FIG. 9B, the surface of the workpiece 2 works as a mirror surface. As a result, the image includes a part of the reader 3 reflected on the workpiece 2 and a whiteout portion caused by mirror reflection. In particular, if the code 6 overlaps with the whiteout portion, the code 6 cannot be correctly decoded. Therefore, there may be cases where it is not preferable to attach the reader 3 to the work 2 having a mirror surface such as a metal surface.

  FIG. 9C is a side view when the reader 3 is obliquely attached to the workpiece 2. As shown in FIG. 9C, some components of the light emitted from the light emitting elements 26 and 27 are specularly reflected by the work 2, but the specularly reflected light of the imaging element 31 is reflected by the skew angle given to the reader 3. Heading in a direction different from the optical axis direction (solid line). On the other hand, the other components of the light emitted from the light emitting elements 26 and 27 are diffusely reflected by the work 2 and enter the imaging element 31 (broken line). FIG. 9D shows an example of an image captured by the image sensor 31 during oblique mounting. As shown in FIG. 9D, the specular reflection light no longer enters the image sensor 31, and the code 6 can be imaged to the extent that it can be decoded.

  FIG. 9E is a side view when the leader 3 is obliquely attached to the workpiece 2. As shown in FIG. 9E, the light specularly reflected by the work 2 does not travel in the direction in which the housing of the reader 3 exists. If there is some object 7 (for example, a human hand) ahead of the specular reflection light, the component of the light reflected by the object 7 out of the specular reflection light is directed toward the surface of the work 2 and is reflected again there. The light may enter the image sensor 31. FIG. 9F shows an example of an image picked up by the image pickup device 31 during oblique mounting. As shown in FIG. 9F, the object 7 appears in the image, which may cause a decoding error. When the skew angle is set such that the top surface side of the reader 3 is raised and the bottom surface side is lowered in this way, the image of the code 6 is affected by the object 7.

<Configuration of diffusion member>
An attachment hood having a diffusing member that can be attached to and detached from the housing of the reader 3 will be described with reference to FIGS. 10 (A) to 10 (C). FIG. 10A is a perspective view showing the reader 3 to which the attachment hood 8 is attached. FIG. 10B is a side view showing the left side surface 98 of the reader 3 to which the attachment hood 8 is attached. FIG. 10C is a diagram showing an image of the code 6 acquired by the reader 3 to which the attachment hood 8 is attached. A diffusion member is provided inside the attachment hood 8 to increase the directivity angle of the illumination light.

  As shown in FIG. 10A and the like, the attachment hood 8 is attached so as to cover the window portion 11 of the reader 3. The attachment hood 8 can be attached to and detached from the reader 3 because there is a workpiece 2 that has a higher matching level when the attachment hood 8 is attached, or a workpiece 2 that has a higher matching level when the attachment hood 8 is not attached. Because it exists. The user can easily improve the matching level by attaching or removing the attachment hood 8 according to the type of the work 2. Further, by providing the attachment hood 8 as an optional part, it will be possible to increase the number of combinations of the workpiece 2 and the code 6 that can be read by the reader 3. The user can increase the number of combinations of readable workpieces 2 and codes 6 simply by purchasing a new attachment hood 8 with respect to the reader 3 that has already been purchased. .

  As shown in FIG. 10B, the attachment angle (skew angle) of the leader 3 is inclined by several degrees (eg, 8 degrees or more and 14 degrees or less) from the angle parallel to the surface of the workpiece 2. As a result, the normal direction of the workpiece 2 and the optical axis of the illumination light (and the normal direction of the imaging surface of the imaging device 31) are not parallel, so that strong specular reflected light does not enter the imaging device 31. As shown in FIG. 10C, since the code 6 becomes an image having sufficient contrast, the matching level is improved.

<Structure of attachment hood>
FIG. 11 is an exploded view showing the structure of the attachment hood 8. The attachment hood 8 is composed of a plurality of parts. The first attachment case 100 is a structural member that forms the exterior of the attachment hood 8. The front surface and the rear surface of the first attachment case 100 are opened to allow illumination light to pass through. Through holes 102 corresponding to the screw holes 45 provided in the housing 9 are provided on the right side surface and the left side surface of the first attachment case 100. The attachment hood 8 is positioned with respect to the reader 3, the screw 101 is inserted into the through hole 102, and the screw 101 is screwed into the screw hole 45. Thereby, the attachment hood 8 is fixed to the reader 3. By adopting such a fastening structure with screws, the attachment hood 8 can be easily attached and detached. Fixing means other than a fastening structure such as a fitting structure may be employed. Two through holes 104 are also provided on the bottom surface of the attachment hood 8, and screws 103 are inserted therein. The screw 103 is a fixing member for fixing the second attachment case 110 to the first attachment case 100. A cylindrical light shielding wall 105 through which the optical axis of the image sensor 31 passes is provided in the approximate center of the first attachment case 100. In the present embodiment, the optical axis of the image sensor 31 and the optical axis of the illumination light from the light emitting elements 26 to 29 are parallel. That is, the illumination light and the reflected light from the work 2 pass through the first attachment case 100. If the illumination light is internally reflected in the first attachment case 100 and enters the image sensor 31, the matching level of the code 6 may be significantly reduced. Therefore, in the present embodiment, the cylindrical light shielding wall 105 is provided so that the illumination light reflected inside the first attachment case 100 does not enter the image sensor 31. As described above, the first attachment case 100 is configured to prevent the light from the first illumination unit and the light from the second illumination unit from leaking onto the optical axis of the image sensor 31 inside the attachment hood 8. A cylindrical light shielding wall may be provided.

  The first diffusing member 120 is provided on the emission axis of light emitted from the light emitting elements 26 and 27 that are the first illumination part and on the emission axis of light emitted from the light emitting elements 28 and 29 that are the second illumination part, The light emitted from the first illumination unit and the light emitted from the second illumination unit are diffused. Here, the first illuminating unit and the second illuminating unit share one diffusing member, but individual diffusing members may be provided. The latter will be advantageous when the diffusivity of the first illuminating unit and the diffusivity of the second illuminating unit are changed depending on the thickness and material of the diffusing member. The former will be advantageous in that the number of parts can be reduced. The imaging lens 122 is an optical component that is disposed on the optical axis of the image sensor 31 and forms an image of the code 6 on the image sensor 31. The first diffusion member 120 is, for example, a diffusion plate having a certain thickness. A U-shaped notch 121 is provided substantially at the center of the first diffusing member 120, and the optical axis of the image sensor 31 passes therethrough. That is, the imaging lens 122 is disposed on the optical axis of the image sensor 31. The size of the U-shaped notch 121 is slightly larger than the cylindrical light shielding wall 105 provided in the first attachment case 100. This is because the first diffusion member 120 can be inserted up to the front surface of the first attachment case 100. The imaging lens 122 is disposed at the rear end of the cylindrical light shielding wall 105 and is fixed thereto. By providing the imaging lens 122, even a very small code 6 can be enlarged and imaged.

  The second attachment case 110 is smaller in size than the inner wall of the first attachment case 100 and can be inserted into the first attachment case 100. The first diffusion member 120 is sandwiched between the edge portion on the front surface side of the first attachment case 100 and the front surface side of the second attachment case 110. The inside of the second attachment case 110 is divided into a plurality of spaces by a plurality of light shielding walls (shielding walls). The first space 111 is a space through which illumination light from the light emitting element 26 passes. The second space 112 is a space through which illumination light from the light emitting element 27 passes. The third space 113 is a space through which illumination light from the light emitting elements 28 and 29 passes. The fourth space 115 is a space through which the optical axis of the image sensor 31 passes and the reflected light from the work 2 passes. A cylindrical light shielding wall 105 is disposed inside the fourth space 115. A cylindrical light shielding wall 105 may be provided on the second attachment case 110. The cylindrical light shielding wall 105 may be provided on both the first attachment case 100 and the second attachment case 110, or may be provided on only one of them.

  The double-sided tape 130 is a fixing member for fixing the second diffusion member 140 to the second attachment case 110. In this example, the second diffusion member 140 is fixed to the lower side of the rear surface of the second attachment case 110 (a position corresponding to the fourth space 115). The double-sided tape 130 has a notch 132 through which illumination light from the light emitting elements 28 and 29 passes and a semicircular notch 131 through which the optical axis of the image sensor 31 passes.

  The second diffusing member 140 has a semicircular cutout 141 through which the optical axis of the image sensor 31 passes. In this example, the second diffusing member 140 is provided at a position where the illumination light from the light emitting elements 28 and 29 passes, but may be provided at a position where the illumination light from the light emitting elements 26 and 27 passes. Light from either the first illumination unit or the second illumination unit passes through both the first diffusion member 120 and the second diffusion member 140. Therefore, this is more diffused than the illumination light that passes only through the first diffusion member 120. The thickness of the first diffusing member 120 and the thickness of the second diffusing member 140 can be appropriately selected according to the target degree of diffusion, but if both are made the same thickness, the same material Therefore, the manufacturing efficiency of the first diffusion member 120 and the second diffusion member 140 can be improved.

  An annular lens support member 150 is a member that holds and supports the imaging lens 122 in cooperation with the rear end of the cylindrical light shielding wall 105, and the upper edge of the lens support member 150 is a first attachment by a screw 151. It is fixed to the case 100. In the first attachment case 100, the cylindrical light shielding wall 105 is suspended from the top surface of the first attachment case 100. A screw hole is provided in the rear surface of the suspension member for suspending the cylindrical light shielding wall 105, and the screw 151 is screwed there.

  The skew angle (attachment angle) θ of the reader 3 will be described with reference to FIGS. 12 (A) to 12 (D). FIG. 12A is a side view when the optical axis of the image sensor 31 of the reader 3 is parallel to the normal of the surface of the workpiece 2 (when front mounted). As shown in FIG. 12A, the length of the top surface of the attachment hood 8 is shorter than the length of the bottom surface so that the front surface of the attachment hood 8 and the surface of the work 2 are not parallel. Note that the length here is the direction along which the optical axis (one-dot broken line) of the image sensor 31 passes. FIG. 12B is a diagram illustrating an example of an image acquired when the optical axis of the image sensor 31 of the reader 3 and the normal line of the surface of the workpiece 2 are parallel (when mounted in front). As shown in FIG. 12B, when the reader 3 is mounted on the front surface, the front surface of the attachment hood 8 is reflected in the image and overlaps with the cord 6, and the matching level of the cord 6 is lowered.

  FIG. 12C is a side view when the optical axis of the image sensor 31 of the reader 3 and the normal of the surface of the work 2 are not parallel (when obliquely attached). FIG. 12D is a diagram illustrating an example of an image acquired when the optical axis of the image sensor 31 of the reader 3 and the normal of the surface of the workpiece 2 are not parallel (when obliquely attached). The matching level of the code 6 is increased by fixing the reader 3 so that the skew angle θ is not less than 0 degrees, and in particular, the skew angle θ is not less than 8 degrees and not more than 14 degrees. This is because, as shown in FIG. 12D, the entrance to the image sensor 31 in the front surface of the attachment hood 8 is less likely to appear in the image. In FIGS. 12B and 12D, the image of the entrance is a semicircular black shadow. According to FIG.12 (C), the front surface of the attachment hood 8 and the surface of the workpiece | work 2 are parallel. Thus, by fixing the reader 3 so that the front surface of the attachment hood 8 is substantially parallel to the surface of the workpiece 2, the skew angle θ of the reader 3 is set to an appropriate angle. That is, the normal direction of the front surface of the attachment hood 8 is inclined by θ with respect to the optical axis direction of the image sensor 31. As a result, the user can easily set the skew angle θ of the reader 3 to the recommended angle. The recommended angle is set according to the reading distance of the reader 3, the reading visual field, and the like.

  FIG. 13A is a view showing the left side surface of the attachment hood to which the attachment guide 160 is attached. FIG. 13B shows an example of the attachment guide 160. The attachment guide 160 is a guide member that guides the attachment angle of the reader 3 recommended by the user or the like. An arrow indicating the optical axis direction is drawn on the attachment guide 160. The attachment guide 160 includes a picture that replicates the reader 3 to which the attachment hood 8 is attached. Further, it is also shown that the skew angle θ is set to a recommended angle (eg, 8 degrees to 14 degrees) by making the front surface of the attachment hood 8 parallel to the workpiece 2. The user can easily grasp the recommended angle of the skew angle θ by looking at the attachment guide 160. In other words, the user can easily adjust the skew angle θ to the recommended angle.

  If the skew angle θ is set such that the bottom surface side of the reader 3 is raised and the top surface side is lowered, the light that is specularly reflected by the work 2 goes to the abdomen of the front surface side of the reader 3. By painting the abdomen with a matte black paint or the like, most of the light toward the abdomen is absorbed there, so that the light toward the cord 6 is reduced. Therefore, the influence of the object 7 as shown in FIG. In addition, in the case where the object 7 does not exist on the top surface side of the reader 3, an attachment hood 8 having a dimension such that the top surface is long and the bottom surface is short may be provided.

<Switching between dark field illumination mode and bright field illumination mode>
The illumination mode in which the code 6 can be easily read may differ depending on the material of the surface of the workpiece 2 and the type of surface processing. As described above, the present embodiment includes the first illumination unit including the light emitting elements 26 and 27 and the second illumination unit including the light emitting elements 28 and 29. Therefore, the imaging control unit 62 switches between the illumination mode in which the first illumination unit is turned on and the second illumination unit is turned off, and the illumination mode in which the second illumination unit is turned on and the first illumination unit is turned off, thereby dark field illumination mode. And bright-field illumination mode.

  FIG. 14A is a side view for explaining the bright field illumination mode. The reader 3 is fixed at a skew angle θ1 that falls within a range of 8 degrees to 14 degrees. The incident angle of the illumination light from the first illumination unit is α1. In this case, the illumination angle with respect to the cord 6 is a so-called low angle illumination as compared with the case shown in FIG. FIG. 14B is a diagram illustrating an example of an image of the code 6 acquired in the bright field illumination mode. A portion of the cord 6 that is not engraved and a surface portion of the work 2 around the cord 6 appear black, and a portion that is engraved appears white. This is because specular reflection is dominant on the surface portion of the workpiece 2 and most of the light does not enter the image sensor 31. On the other hand, diffuse reflection is dominant in the engraved portion, and the amount of light incident on the image sensor 31 is increased as compared with the surface portion of the workpiece 2, so that the engraved portion appears white. In this way, a so-called bright field image is obtained in which the engraved portion of the code 6 appears white and the surface portion of the workpiece 2 appears black.

  FIG. 14C is a side view for explaining the dark field illumination mode. The reader 3 is fixed at a skew angle θ1 that falls within a range of 8 degrees to 14 degrees. The incident angle of the illumination light from the second illumination unit is α2. Here, α2 <α1 holds. That is, the illumination angle with respect to the code 6 in the dark field illumination mode is a high angle compared to the angle in the bright field illumination mode. FIG. 14D is a diagram illustrating an example of an image of the code 6 acquired in the dark field illumination mode. A portion of the cord 6 that is not engraved and a surface portion of the work 2 around the cord 6 appear white, and a portion that is engraved appears black. This is because specular reflection is dominant on the surface portion of the workpiece 2 and most of the light is incident on the image sensor 31. On the other hand, diffuse reflection is dominant in the engraved portion, and the amount of light incident on the image sensor 31 is reduced as compared with the surface portion of the workpiece 2, so that the engraved portion appears black. Thus, a so-called dark field image is obtained in which the engraved portion of the code 6 appears black and the surface portion of the work 2 appears white.

  As described above, in the present embodiment, the first illumination unit disposed on the top surface side with respect to the optical axis of the image sensor 31 is turned on, and the second illumination disposed on the bottom surface side with respect to the optical axis of the image sensor 31. The bright field illumination mode is realized by turning off the light. On the other hand, the dark field illumination mode is realized by turning off the first illumination unit and turning on the second illumination unit. Depending on the work 2, which illumination mode is suitable can be changed. Therefore, a more appropriate illumination mode may be selected by performing tuning in advance.

  FIG. 15 is a flowchart illustrating an example of tuning processing. Here, the tuning unit 65 of the reader 3 is described as executing the tuning process, but the calculation unit 81 of the computer 4 may execute a part of the tuning process. Note that a reading success rate may be obtained instead of the matching level.

  In S <b> 1, the tuning unit 65 selects the bright field illumination mode, and instructs the illumination unit 52 to emit light in the bright field illumination mode through the imaging control unit 62. In the bright field illumination mode, the light emitting elements 26 and 27 are turned on. The light emitting elements 28 and 29 are turned off.

  In S <b> 2, the tuning unit 65 reads the code while changing the light amount stepwise to obtain a matching level. For example, the tuning unit 65 sets the first level among the n light quantity levels for the illumination unit 52 to light the light emitting elements 26 and 27. Further, the tuning unit 65 causes the AF control unit 61 to start AF control, and when the AF control unit 61 reports that it is in focus, causes the imaging control unit 62 to execute the code 6 imaging. The tuning unit 65 sends the image of the code 6 to the decoding unit 53 to execute decoding, and causes the calculation unit 63 to calculate the matching level using the decoding result. The matching level is obtained for each of the n light quantity levels.

  In S3, the tuning unit 65 selects the dark field illumination mode, and instructs the illumination unit 52 to emit light in the dark field illumination mode through the imaging control unit 62. In the dark field illumination mode, the light emitting elements 28 and 29 are turned on. The light emitting elements 26 and 27 are turned off.

  In S4, the tuning unit 65 reads the code while gradually changing the light amount, and obtains a matching level. For example, the tuning unit 65 sets the first level among the n light quantity levels for the illumination unit 52 through the imaging control unit 62 and turns on the light emitting elements 28 and 29. Further, the tuning unit 65 causes the AF control unit 61 to start AF control, and when the AF control unit 61 reports that it is in focus, causes the imaging control unit 62 to execute the code 6 imaging. The tuning unit 65 sends the image of the code 6 to the decoding unit 53 to execute decoding, and causes the calculation unit 63 to calculate the matching level using the decoding result. The matching level is obtained for each of the n light quantity levels.

  In S5, the tuning unit 65 selects a combination of the illumination mode and the light amount level that is the highest matching level among the n matching levels for the bright field illumination mode and the n matching levels for the dark field illumination mode. decide. As a result, an illumination mode and a light amount level suitable for the combination of the workpiece 2 and the code 6 are selected and stored in the setting data 73. The setting data 73 is read by the control unit 60 and set in the imaging control unit 62 when reading of the code 6 for the workpiece 2 conveyed on the line 1 is started. The imaging control unit 62 turns on the light emitting element in the illumination mode and the light amount level according to the setting data 73.

  The decoding result 71 such as the matching level for each combination of the illumination mode and the light amount level may be transmitted from the tuning unit 65 to the computer 4 and displayed on the display unit 84. The image data 72 acquired for each combination may also be transmitted from the tuning unit 65 to the computer 4 and displayed on the display unit 84.

<Relationship between skew angle and presence / absence of diffusion member>
Here, the relationship between the skew angle θ and the presence or absence of the diffusing member will be described. Here, the light emitting elements 26 and 27 are both turned on, and the light emitting elements 28 and 29 are turned off.

  FIG. 16A shows an image of the code 6 obtained when the skew angle θ is set to 12 degrees without providing the diffusing member. FIG. 16B shows an image of the code 6 obtained when the skew angle θ is set to 8 degrees without providing the diffusing member. As can be seen by comparing FIG. 16A and FIG. 16B, when the skew angle θ decreases, the contrast of the read image of the code 6 decreases. This will reduce the matching level.

  FIG. 16C shows an image of the code 6 obtained when the diffusion member is provided and the skew angle θ is set to 12 degrees. FIG. 16D shows an image of the code 6 obtained when the diffusion member is provided and the skew angle θ is set to 8 degrees. As can be seen by comparing FIG. 16C and FIG. 16D, the influence of the difference in the skew angle θ on the contrast of the read image of the code 6 is reduced. Further, as can be seen from a comparison between FIG. 16B and FIG. 16D, even when the skew angle θ is 8 degrees, the contrast of the read image of the code 6 is improved sufficiently. Therefore, the matching level is also a sufficient value. Thus, by attaching the attachment hood 8 provided with the diffusing member to the reader 3, the degree of freedom of the skew angle θ can be increased. That is, since the degree of freedom of attachment increases for the user, the reader 3 can be introduced into various production lines.

<Number of diffusion members>
In the present embodiment, the number of diffusion members is changed between the first illumination unit and the second illumination unit. The number of both diffusion members may be the same, but the advantage of making them different will be described. Here, the light emitting elements 26 and 27 are both turned off, and the light emitting elements 28 and 29 are turned on.

  FIG. 17A shows an image of the code 6 obtained when the skew angle θ is set to 12 degrees without providing the diffusing member. FIG. 17B shows an image of the code 6 obtained when one diffusion member is provided and the skew angle θ is set to 12 degrees. FIG. 17C shows an image of the code 6 obtained when two diffusion members are provided and the skew angle θ is set to 12 degrees. In particular, comparing FIG. 17A to FIG. 17C, it can be seen that there is an appropriate value for the diffusion degree of the diffusion member. For example, as can be seen from a comparison between FIG. 17B and FIG. 17C, the light-emitting elements 28 and 29 have insufficient diffusivity with only one diffusing member, and whiteout occurs in part of the image. Resulting in. Therefore, two diffusing members should be adopted for the light emitting elements 28 and 29 arranged on the bottom side of the optical axis of the image pickup element 31. In addition, as for the light emitting elements 26 and 27 arranged on the top surface side with respect to the optical axis of the imaging element 31, a single diffusing member should be adopted as shown in FIG. This is because if the number of the diffusing members is increased, the amount of light returning from the cord 6 is reduced, and the matching level is lowered.

<Summary>
According to the present embodiment, the illumination unit 52 emits light from a first region (light emission region that is a part of the window 11) on the first surface side (front surface 96) of the housing 9. It is an example of the illumination means containing (the light emitting elements 26 and 27) and the 2nd illumination part (light emitting elements 28 and 29). The imaging element 31 has an optical axis parallel to the light emission direction of the first illumination unit and the light emission direction of the second illumination unit. The image sensor 31 is light incident from a second region (light incident region that is a part of the window portion 11) on the first surface side of the housing 9, which is different from the first region. The cord 6 provided on the work 2 is imaged by receiving the reflected light. The decoding unit 53 functions as a decoding unit that decodes the code 6 imaged by the imaging device 31. The attachment hood 8 is detachable from the housing 9 and is an example of an attachment hood that surrounds the first region and the second region. As described with reference to FIG. 11, the attachment hood 8 includes the imaging lens 122 that is disposed on the optical axis of the image sensor 31 and forms an image of the code 6 on the image sensor 31. Since the imaging lens 122 functions as a close-up lens, it is possible to magnify and capture even a small size code 6. Note that when a small-sized code 6 is imaged, the reading distance (the distance from the code 6 to the window 11 of the reader 3) is shortened. However, in this case, much of the amount of reflected light is incident on the image sensor 31 and the contrast of the cord 6 is lowered. Therefore, the attachment hood 8 is provided on the emission axis of the light emitted from the first illumination unit and on the emission axis of the light emitted from the second illumination unit, and the light emitted from the first illumination unit and the second illumination unit The first diffusing member 120 is provided as a diffusing means for diffusing the light emitted from the light. By providing the first diffusing member 120, the illumination light is diffused, so that the specular reflected light incident on the image sensor 31 is reduced. This will improve the contrast of the code 6 and improve the matching level. Thus, the reader 3 capable of accurately reading the code 6 attached to the workpiece 2 that causes specular reflection is provided. In addition, it is possible to switch the presence or absence of the imaging lens by attaching or detaching the attachment hood 8. Thereby, it becomes possible to easily improve the matching level for a plurality of workpieces 2 and codes 6 having different appropriate reading distances.

  As described above, since the attachment hood 8 can be detached from the reader 3, the attachment hood 8 can be attached or detached according to the workpiece 2 or the cord 6. This is because, depending on the workpiece 2 and the cord 6, the matching level may be improved when the diffusing member is provided, or the matching level may be improved when the diffusing member is not provided. The user can improve the matching level by attaching or removing the attachment hood 8 according to the workpiece 2 or the cord 6.

  As described with reference to FIGS. 14 and 15, the illumination unit 52 lights the first illumination unit and does not light the second illumination unit, and the first illumination mode (bright field illumination mode) and the first illumination. The second illumination mode (dark field illumination mode) for turning off the light source and turning on the second illumination part may be provided. As a result, an illumination mode suitable for the workpiece 2 can be selected.

  As described with reference to FIG. 11, the first diffusing member 120 includes a first diffusing portion (upper side of the first diffusing member 120) provided on the emission axis of the light emitted from the first illuminating portion, and the second diffusing member 120. You may have the 2nd diffuser (the lower side of the 1st diffuser 120, and the 2nd diffuser 140) provided on the outgoing axis of the light radiate | emitted from an illumination part. In this case, the diffusivity of the first diffusion part is different from the diffusivity of the second diffusion part. As a result, it is possible to irradiate the cord 6 with the illumination light through two types of diffusion portions having different diffusion rates. Depending on the surface material of the workpiece 2, the reading distance, and the like, the appropriate diffusion rate may vary. Therefore, it becomes possible to select illumination light suitable for the code 6 by switching and illuminating a plurality of diffusion units having different diffusion rates.

  As described with reference to FIGS. 11 and 14A to 14D, the diffusivity of the first diffusing portion is smaller than the diffusivity of the second diffusing portion. As a result, the attenuation of the illumination light through the first diffusion unit can be reduced, and the illumination light through the second diffusion unit can be further diffused. In this way, it becomes easy to switch the light quantity and the directivity of the illumination light.

  The first diffusion portion has one diffusion plate (first diffusion member 120), and the second diffusion portion has two diffusion plates (first diffusion member 120 and second diffusion member 140). Good. As shown in FIG. 11, one diffusion plate (first diffusion member 120) constituting the first diffusion portion and one diffusion plate (first diffusion member 120) constituting the second diffusion portion are common. A diffusion plate may be used. As a result, the number of parts can be reduced, and the manufacturing cost can be reduced. The thickness of one diffusion plate (first diffusion member 120) that the first diffusion portion has, and the thickness of each of the two diffusion plates (first diffusion member 120 and second diffusion member 140) that the second diffusion portion has May be the same. That is, a plurality of diffusion plates can be produced by cutting the same material, and the manufacturing cost can be reduced. The two diffusion plates included in the second diffusion unit may be arranged in parallel.

  The first diffusion member 120 may be divided into a portion (first diffusion plate) that forms the first diffusion portion and a portion (third diffusion plate) that forms a part of the second diffusion portion. In this case, the second diffusion part will be constituted by the second diffusion plate and the third diffusion plate formed by the second diffusion member 140. By adopting the first diffusion plate and the third diffusion plate, the diffusion degree of the first diffusion plate and the diffusion degree of the third diffusion plate can be individually set. The degree of freedom in adjusting the diffusivity of the illumination section will be further increased.

  The directivity of light emitted from the first illumination unit and diffused by the first diffusion unit may be different from the directivity of light emitted from the second illumination unit and diffused by the second diffusion unit. Depending on the type of the work 2 or the code 6, the appropriate directivity may be different. According to this embodiment, since the diffusivity is different between the first illumination unit and the second illumination unit, it is easy to select which one of the first illumination unit and the second illumination unit is lit. The directivity of illumination light can be changed.

  As described with reference to FIGS. 14A to 14D and FIG. 15, the image sensor 31 acquires a bright field image of the code in the first illumination mode and the dark field of the code in the second illumination mode. Get an image. As a result, it is possible to easily switch between the dark field and the bright field.

  As described with reference to FIG. 15, the tuning unit 65 or the like acquires the decoding result obtained by experimentally illuminating the work 2 in the first illumination mode and the work illuminating the work in the second illumination mode. You may function as a determination means which determines the illumination mode used in order to acquire a better decoding result among decoding results. The illumination unit 52 illuminates the workpiece 2 in the illumination mode determined by the tuning unit 65 or the like. As a result, the workpiece 2 and the cord 6 are illuminated in a more suitable illumination mode, and the matching level will be improved.

  As described with reference to FIG. 11 and the like, the normal direction of the light exit surface from the first illumination unit in the first diffusion member 120 and the normal direction of the first region (window portion 11), The normal direction of the light emission surface from the second illuminating unit in one diffusing member 120 is different. In particular, the light emission axis from the first illumination part and the light emission surface of the first diffusion member 120 are not perpendicular to each other, but the light emission axis from the second illumination part and the light emission from the first diffusion member 120 It may not be perpendicular to the exit surface. That is, the front surface of the attachment hood 8 is not parallel to the window portion 11. This would be suitable for preventing the specular reflected light from the work 2 from entering the image sensor 31. The angle formed by the normal direction of the window portion 11 and the normal direction of the front surface of the attachment hood 8 is the same as the angle formed by the window portion 11 and the front surface of the attachment hood 8. As described above, there is a recommended angle for the skew angle θ of the reader 3. Therefore, by designing these angles to be the recommended angles, the skew angle θ of the reader 3 can be easily installed to be the recommended angle. This is because, as described with reference to FIG. 12C, if the front surface of the attachment hood 8 is installed in parallel to the surface of the workpiece 2, the skew angle θ of the reader 3 naturally matches the recommended angle.

  The first illuminating unit is provided near the longitudinal end of the first surface of the housing 9 (that is, the top surface 94), and the second illuminating unit is the longitudinal direction of the first surface of the housing 9. It may be provided away from the end of the. By switching between the first illumination unit and the second illumination unit, the incident angle of the illumination light with respect to the workpiece 2 can be switched.

  The light emission surface from the first illumination unit and the light emission surface from the second illumination unit in the first region (window portion 11) may be on the same surface. As shown in FIG. 7A and FIG. 7B, when the window portion 11 forms the light emission surface from the first illumination portion and the light emission surface from the second illumination portion, both emission surfaces are formed. Are on the same plane. Similarly, the light emission surface from the first illumination unit and the light emission surface from the second illumination unit in the first diffusion member 120 may be on the same surface.

  As shown in FIG. 9, FIG. 10 (B), FIG. 12 (A), FIG. 12 (B), etc., the fixed reader 3 is in the normal direction of the surface of the workpiece 2 on which the cord 6 is provided. On the other hand, it may be installed so that the normal direction of the imaging surface of the image sensor 31 is different. By setting the skew angle θ to a certain value in this way, the incidence of specular reflection light is reduced, and the code 6 can be read with an appropriate amount of light.

  The housing 9 may be fixed so that the skew angle θ with respect to the conveying member (line 1) that conveys the workpiece 2 is not less than 8 degrees and not more than 14 degrees. Thus, by adjusting the skew angle θ to the recommended angle, the incidence of specular reflection light is reduced, and the matching level of the cord 6 will be improved.

  As described with reference to FIG. 11, the attachment hood 8 may include the first attachment case 100 and the second attachment case 110 that supports the first diffusion member 120. Thereby, the first diffusion member 120 can be fixed. The second attachment case 110 may have a shielding wall that shields a space through which light from the first illumination unit passes and a space through which light from the second illumination unit passes inside the attachment hood 8. Thereby, it becomes possible to make the light from a 1st illumination part and the light from a 2nd illumination part independent. It becomes possible to clarify the switching effect between the first illumination unit and the second illumination unit. In order to increase the diffusivity of the second illumination unit, a light shielding wall may be omitted between the space through which the illumination light of the light emitting element 28 passes and the space through which the illumination light of the light emitting element 29 passes. .

  In at least one of the first attachment case 100 and the second attachment case 110, the light from the first illumination unit and the light from the second illumination unit are on the optical axis of the image sensor 31 inside the attachment hood 8. A cylindrical light shielding wall (such as a cylindrical light shielding wall 105) for preventing leakage may be provided. When the light reflected inside the attachment hood 8 is incident on the image sensor 31, the contrast of the image of the cord 6 can be lowered. Therefore, by reducing or preventing this by the light shielding wall, it will be possible to improve the contrast and improve the matching level.

  As described with reference to FIG. 13, the installation angle of the housing 9 with respect to the workpiece 2 may be illustrated on the side surface of the attachment hood 8. As a result, the user can easily adjust the skew angle of the reader 3 without referring to the instruction manual.

  According to the present embodiment, an optical reading method using a fixed optical information reading device is also provided. A user (which may be a person in charge of installation or not necessarily a user of the reader 3) attaches the attachment hood 8 to the housing 9. Further, the user fixes the housing 9 so that the light diffused by the first diffusing member 120 is reflected by the surface of the workpiece and received by the image sensor 31. The user causes the image sensor 31 to image the code 6. The user causes the decoding unit 53 to decode the code imaged by the image sensor 31. As a result, the code 6 can be read with high accuracy.

  The light emitting elements 26 to 29 may be LEDs that emit red light. Since the red LED is cheaper than the blue LED and the white LED, the manufacturing cost of the reader 3 will be reduced.

  As shown in FIG. 11 and the like, the position of the center of gravity of the reader 3 exists at a position biased to the top surface side rather than the bottom surface side. In particular, when the attachment hood 8 is attached, the position of the center of gravity of the reader 3 further moves to the top surface side due to the weight of the attachment hood 8. Such a center of gravity arrangement makes it easy to fix the reader 3 by lowering the top surface side of the reader 3 from the bottom surface side.

  DESCRIPTION OF SYMBOLS 1 ... Line, 2 ... Work, 3 ... Reader, 4 ... Computer, 5 ... PLC, 6 ... Code, 8 ... Diffuse reflection member

Claims (22)

A housing,
An illuminating means including a first illuminating unit and a second illuminating unit that emit light from the light emitting region on the first surface side of the housing;
Light incident on the first surface side of the housing having an optical axis parallel to the light emission direction of the first illumination unit and the light emission direction of the second illumination unit, which is different from the light emission region Imaging means for imaging a code provided on the workpiece by receiving light reflected from the workpiece, which is light incident from a region;
Decoding means for decoding the code imaged by the imaging means;
An attachment hood that is detachable from the housing and surrounds the light emitting region and the light incident region;
Have
The attachment hood is
An imaging lens disposed on the optical axis of the imaging means and forming an image of the code on the imaging means;
Provided on the emission axis of light emitted from the first illumination unit and on the emission axis of light emitted from the second illumination unit, and emitted from the first illumination unit and the second illumination unit have a diffusion means for diffusing light,
The first illumination unit is provided near an end in a longitudinal direction of the first surface of the housing,
The fixed optical information reader according to claim 1, wherein the second illumination unit is provided apart from an end of the first surface of the housing in the longitudinal direction . A housing,
An illuminating means including a first illuminating unit and a second illuminating unit that emit light from the light emitting region on the first surface side of the housing;
Light incident on the first surface side of the housing having an optical axis parallel to the light emission direction of the first illumination unit and the light emission direction of the second illumination unit, which is different from the light emission region Imaging means for imaging a code provided on the workpiece by receiving light reflected from the workpiece, which is light incident from a region;
Decoding means for decoding the code imaged by the imaging means;
An attachment hood that is detachable from the housing and surrounds the light emitting region and the light incident region;
Have
The attachment hood is
An imaging lens disposed on the optical axis of the imaging means and forming an image of the code on the imaging means;
Provided on the emission axis of light emitted from the first illumination unit and on the emission axis of light emitted from the second illumination unit, and emitted from the first illumination unit and the second illumination unit Diffusing means for diffusing light ,
The diffusion means is
A first diffusion part provided on an emission axis of light emitted from the first illumination part;
A second diffusing unit provided on an emission axis of light emitted from the second illumination unit;
Have
A fixed optical information reading apparatus, wherein a diffusion rate of the first diffusion unit is different from a diffusion rate of the second diffusion unit. A housing,
An illuminating means including a first illuminating unit and a second illuminating unit that emit light from the light emitting region on the first surface side of the housing;
Light incident on the first surface side of the housing having an optical axis parallel to the light emission direction of the first illumination unit and the light emission direction of the second illumination unit, which is different from the light emission region Imaging means for imaging a code provided on the workpiece by receiving light reflected from the workpiece, which is light incident from a region;
Decoding means for decoding the code imaged by the imaging means;
An attachment hood that is detachable from the housing and surrounds the light emitting region and the light incident region;
Have
The attachment hood is
An imaging lens disposed on the optical axis of the imaging means and forming an image of the code on the imaging means;
Provided on the emission axis of light emitted from the first illumination unit and on the emission axis of light emitted from the second illumination unit, and emitted from the first illumination unit and the second illumination unit Diffusing means for diffusing light ,
An emission axis of light from the first illumination unit and an emission surface of light in the diffusing means, or
At least one of the light emission axis from the second illuminating unit and the light emission surface of the diffusing means is not vertical, and is a fixed optical information reader. A housing,
An illuminating means including a first illuminating unit and a second illuminating unit that emit light from the light emitting region on the first surface side of the housing;
Light incident on the first surface side of the housing having an optical axis parallel to the light emission direction of the first illumination unit and the light emission direction of the second illumination unit, which is different from the light emission region Imaging means for imaging a code provided on the workpiece by receiving light reflected from the workpiece, which is light incident from a region;
Decoding means for decoding the code imaged by the imaging means;
An attachment hood that is detachable from the housing and surrounds the light emitting region and the light incident region;
Have
The attachment hood is
An imaging lens disposed on the optical axis of the imaging means and forming an image of the code on the imaging means;
Provided on the emission axis of light emitted from the first illumination unit and on the emission axis of light emitted from the second illumination unit, and emitted from the first illumination unit and the second illumination unit Diffusing means for diffusing light ,
The attachment hood has a first attachment case and a second attachment case that supports the diffusion means,
The second attachment case has a shielding wall that shields a space through which light from the first illumination unit passes and a space through which light from the second illumination unit passes inside the attachment hood. A fixed optical information reader characterized by the above. The illumination means includes
A first illumination mode in which the first illumination unit is lit and the second illumination unit is not lit;
A second illumination mode for turning off the first illumination unit and turning on the second illumination unit;
Claims 1, characterized in that it has a to 4 stationary optical information reading apparatus according to any one of. The diffusion means is
A first diffusion part provided on an emission axis of light emitted from the first illumination part;
A second diffusing portion provided on an emission axis of light emitted from the second illumination portion,
And spreading factor of the first spreading section, reading fixed optical information according to any one of claims 1, 3 and 4, characterized in that different diffusion rate of the second diffusion part apparatus. The fixed optical information reader according to claim 2 or 6, wherein a diffusion rate of the first diffusion unit is smaller than a diffusion rate of the second diffusion unit. The first diffusion part has one diffusion plate,
It said second diffusion portion is fixed an optical information reading apparatus according to any one of claims 2, 6, 7, characterized in that it has two diffusion plates. 9. The fixed optical system according to claim 8 , wherein one diffusion plate constituting the first diffusion portion and one diffusion plate constituting the second diffusion portion are a common diffusion plate. Information reader. The thickness of one of the diffusion plate, wherein said first diffusion portion has, the second is a two diffusion plates each having a thickness of the diffusion section has to, wherein the at least claim 8 or 9, wherein the fixed Optical information reader. Fixed optical information reading apparatus according to any one of claims 8 to 10 two of the diffusion plate where the second diffusion part has is characterized by being arranged in parallel. The directivity of light emitted from the first illumination unit and diffused by the first diffusion unit is different from the directivity of light emitted from the second illumination unit and diffused by the second diffusion unit. fixed optical information reading apparatus according to any one of claims 2, 6 to 11, characterized in that there. 6. The fixed type according to claim 5 , wherein the imaging unit acquires a bright field image of the code in the first illumination mode and acquires a dark field image of the code in the second illumination mode. Optical information reader. A better decoding result is obtained from a decoding result obtained by illuminating the workpiece in a test in the first illumination mode and a decoding result obtained by illuminating the workpiece in a test in the second illumination mode. Further comprising a determining means for determining the illumination mode used for
The fixed optical information reading apparatus according to claim 5 , wherein the illuminating unit illuminates the workpiece in an illumination mode determined by the determining unit. The normal direction of the light exit surface from the first illuminating unit in the diffusing unit and the method of the light exit surface from the second illuminating unit in the diffusing unit with respect to the normal direction of the light emitting region The fixed optical information reading device according to any one of claims 1 to 14, wherein a linear direction is different. The light emission axis from the first illumination unit and the light emission surface of the diffusion means are not perpendicular,
Wherein the emission axis of the light from the second illumination unit, a fixed optical information according to any one of claims 1 to 15, characterized in that it is not perpendicular to the exit surface of the light in the diffuser Reader. The light emission surface from the first illumination unit in the light emission region and the light emission surface from the second illumination unit are on the same surface,
An exit surface of the light from the first illuminating portion of the diffusion means, any one of claims 1 to 16, characterized in that on the same plane and the exit surface of the light from the second illumination unit The fixed optical information reading device according to Item. Further comprising a window portion that forms a light emission surface from the first illumination portion and a light emission surface from the second illumination portion, and the front surface of the attachment hood is from the first illumination portion in the diffusing means. A light emitting surface of the second illumination unit and a light emitting surface of the second illuminating unit, and an angle formed by the window unit and the front surface of the attachment hood is a recommended skew angle of the optical information reading device. The fixed optical information reading device according to claim 17 , wherein the optical information reading device matches the angle. The fixed optical information reading device is installed such that a normal direction of an imaging surface of the imaging unit is different from a normal direction of a surface of the workpiece on which the code is provided. A fixed optical information reading device according to any one of claims 1 to 18 . At least one of the first attachment case and the second attachment case is configured such that the light from the first illumination unit and the light from the second illumination unit are optical axes of the imaging unit inside the attachment hood. 5. The fixed optical information reader according to claim 4 , further comprising a cylindrical light shielding wall for preventing leakage from above. The fixed optical information reading device according to any one of claims 1 to 20 , wherein an installation angle of the housing with respect to the workpiece is illustrated on a side surface of the attachment hood. A housing,
An illuminating means including a first illuminating unit and a second illuminating unit that emit light from the light emitting region on the first surface side of the housing;
Light incident on the first surface side of the housing having an optical axis parallel to the light emission direction of the first illumination unit and the light emission direction of the second illumination unit, which is different from the light emission region Imaging means for imaging a code provided on the workpiece by receiving light reflected from the workpiece, which is light incident from a region;
Decoding means for decoding the code imaged by the imaging means;
An optical reading method using a fixed optical information reading device having:
An attachment hood that is detachable from the housing and surrounds the light emitting area and the light incident area, is disposed on the optical axis of the imaging means, and forms an image of the code on the imaging means The imaging lens is provided on an emission axis of light emitted from the first illumination unit and on an emission axis of light emitted from the second illumination unit, and the light emitted from the first illumination unit and the second have a diffusion means for diffusing the light emitted from the illumination unit, the light emission axis from the exit surface, or the second illumination portion of the light at the diffusing means and the exit axis of the light from the first illumination unit Attaching the attachment hood to the housing, wherein at least one of the light exit surfaces of the diffusing means is not vertical ;
The casing is arranged so that the light diffused by the diffusing means is reflected by the surface of the workpiece and received by the imaging means , and the optical axis of the imaging means and the normal of the workpiece surface are not parallel. Fixing, and
Imaging the code by the imaging means;
And a step of decoding by the decoding means the code imaged by the imaging means.