Optical displacement sensor

Abstract

Provided is an optical displacement sensor using a head as a housing miniaturization. A relay cable extending from the head is integrated with the body. The head is mainly responsible for projecting light to an object to be detected and receiving light from the object to be detected, while the body is composed of a power supply circuit, a display portion, and an operation portion. The head includes a green laser light source and emits green laser light to form a light spot on the surface of the object to be detected.

Description

TECHNICAL FIELD

[0001] The present application relates to an optical displacement sensor. BACKGROUND

[0002] JP 2008-145158A and JP 2008-145160A disclose an optical displacement sensor. The optical displacement sensor is used to detect an object to be detected on which light is projected onto a detection region, a light receiving element receives reflected light, and then the object to be detected is detected based on the output of the light receiving element.

[0003] As is well known, such a displacement sensor is either integrated or separated. In an integrated displacement sensor, a display portion and an operation portion are provided together with a light projection and reception portion in a single housing.

[0004] A separated displacement sensor includes a head portion including a power supply circuit and projecting and receiving light, and a control portion (separated amplifier) that controls the head portion, and the separated amplifier is provided with the display portion and the operation portion and is fixed to a DIN rail.

[0005] Since the integrated displacement sensor is provided with the display portion and the operation portion, the size of the integrated displacement sensor is large, which imposes a limitation on the installation site, for example, when the integrated displacement sensor is installed in a narrow space, the display portion cannot be seen or the operation portion cannot be operated.

[0006] The separated displacement sensor requires a miswiring protection circuit to protect the sensor from a pairing failure between the head portion and the separated amplifier, which complicates the circuit structure of the head portion. SUMMARY

[0007] Therefore, an object of the present application is to provide an optical displacement sensor that allows further downsizing of a housing used as a head portion.

[0008] According to one embodiment of the present application, there is provided an optical displacement sensor including: a first housing including a transmission window that transmits light; a light projection portion provided in the first housing and projecting measurement light toward a detection region through the transmission window; a light reception portion provided in the first housing and photoelectrically converting measurement light from the detection region through the transmission window to generate a light reception signal; a measurement portion provided in the first housing and measuring a displacement of an object to be detected based on the light reception signal generated by the light reception portion; a cable transmitting electric power to the first housing; and a second housing connected to the first housing through the cable, including at least a first power supply circuit that supplies electric power of a first voltage to the first housing through the cable and being integrated with the cable.

[0009] According to one embodiment of the present application, miniaturization can be achieved by accommodating a first power supply circuit for inclusion in a first housing in a second housing, and by integrating a cable extending from the first housing with the second housing to eliminate the I / O port of the first housing.

[0010] The effects and advantages of the present application will become apparent from the detailed description of the preferred embodiments given below. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a diagram for describing the overall structure of an optical triangulation sensor according to a first embodiment;

[0012] Figure 2 is a diagram for describing that a body serving as a part of the optical triangulation sensor according to the first embodiment can be fixed at a desired site, which shows an example of fixing the body at a desired site with a bundle tie;

[0013] Figure 3 is a diagram showing an example of fixing the body to a cable bundle with a bundle tie;

[0014] Figure 4 is a diagram for describing components built in a head serving as a part of the optical triangulation sensor according to the first embodiment;

[0015] Figure 5 is a sectional view for describing the structure of an operation indicator lamp mounted at a tilt corner of the head;

[0016] Figure 6A is a block diagram for describing a control system of the head, which shows a part of the head;

[0017] Figure 6B is a block diagram for describing a control system of the head, which shows another part of the head;

[0018] Figure 7 is a block diagram for describing a control system of the body;

[0019] Figure 8 is a diagram for describing an example of display on an OELD serving as a display part of the body when optical axis displacement occurs;

[0020] Figure 9 is a diagram for describing that a current value and a threshold value are displayed in numerical form on the OELD during operation;

[0021] Figure 10 is a diagram for describing a specific example of bar display when displayed in a distance mode for a threshold setting;

[0022] Figure 11is a diagram for describing a specific example of bar display when displayed in a high mode for a threshold setting;

[0023] Figure 12 is a diagram for describing a power supply circuit included in the head and the body;

[0024] Figure 13 is a flowchart for describing control of the restriction of the intensity and power of the green laser light;

[0025] Figures 14A to 14C is a diagram for describing an explanation when the intensity of the received light is too high and an explanation when the intensity of the received light is too low;

[0026] Figure 14A shows a case where the intensity of the received light is too high;

[0027] Figure 14B shows a case where the intensity of the received light is too low;

[0028] Figure 14C shows the intensity of the received light after adjusting the intensity of the projected light;

[0029] Figure 15 is a flowchart showing an example of a process of controlling the intensity of the laser light by changing the settings of the exposure time of the imaging element and the pulse width of the projected light;

[0030] Figure 16 is a flowchart showing an example of a light intensity control process;

[0031] Figure 17 is a flowchart showing an example of an overcurrent detection process;

[0032] Figure 18A is a diagram for describing that the position of the image of the light spot in the imaging element changes in a manner depending on the distance from the workpiece position;

[0033] Figure 18B is a diagram for describing an image of image pixels arranged at unequal intervals;

[0034] Figures 19A to 19D is a diagram for describing an explanation of an imaging element in which pixels are arranged at equal intervals;

[0035] Figures 20A to 20D is a diagram for describing the setting of the pixel width of an imaging element in which pixels are arranged at unequal intervals;

[0036] Figure 21 is an exploded perspective view of a light projection receiving portion of the head;

[0037] Figure 22is a view for describing that both the trunk cable and the output cable connected to the body are integrally connected to the body by welding;

[0038] Figure 23 is a side view for describing the water-blocking structure of the body, in which the cover on the left side is in a loosened state and the cover on the right side is in a tightened state when viewed from the front;

[0039] Figure 24 is Figure 23 a cross-sectional view of the body shown in FIG. 1;

[0040] Figure 25 is Figure 24 an enlarged cross-sectional view of the portion indicated by an arrow XXV shown in FIG. 1;

[0041] Figure 26 is an enlarged cross-sectional view corresponding to Figure 25 , which shows a state in which the cover is closed;

[0042] Figure 27 is a view for describing the overall structure of the optical triangulation sensor according to the second embodiment;

[0043] Figure 28A is a block diagram for describing the control system of the head body included in the second embodiment, which shows a portion of the head;

[0044] Figure 28B is a block diagram for describing the control system of the head body included in the second embodiment, which shows another portion of the head;

[0045] Figure 29 is a view for describing the power supply circuit of the head body, the trunk, and the body included in the second embodiment;

[0046] Figure 30 is a conceptual view for describing the water-proof structure of the trunk included in the optical triangulation sensor according to the second embodiment; and

[0047] Figure 31 is a block diagram of the trunk included in the second embodiment, in which the power supply circuit drawn out from the head body is provided in the trunk. DETAILED DESCRIPTION

[0048] <First Embodiment( Figures 1 to 26 )

[0049] Figure 1A displacement sensor according to the first embodiment is shown. Specifically, the displacement sensor according to the first embodiment is an optical triangulation sensor 100. The triangulation sensor 100 is composed of a head 2 serving as a first housing and a body 4 serving as a second housing, and a relay cable 6 extending from the head 2 is integrated with the body 4. The head 2 is mainly responsible for projecting light to an object to be detected and receiving light from the object to be detected, while the body 4 is composed of a power supply circuit, a display section, and an operation section. The head 2 includes a green laser light source, and emits green laser light to form a light spot on a surface of the object to be detected.

[0050] In the triangulation sensor 100 according to the first embodiment, the head 2 having no display function is only responsible for projecting light to the object to be detected and receiving light from the object to be detected, thereby allowing the head 2 to be miniaturized. This in turn increases the degree of freedom in determining a place where the head 2 is installed. Further, the body 4 integrated with the head 2 through the relay cable 6 also has the degree of freedom in determining a place where the body 4 is installed. Therefore, placing the head 2 at a position suitable for measurement of the object to be detected and placing the body 4 at any desired position near the head 2 allows setting work such as setting of a judgment threshold and the like to be performed while visually recognizing a light spot of the green laser light appearing on the surface of the object to be detected to determine whether the position of the light spot is appropriate and watching the display section of the body 4.

[0051] Power is supplied from the body 4 to the head 2, and signals are exchanged between the body 4 and the head 2. The relay cable 6 can be connected to the head 2 and / or the body 4 with a connection portion inserted between the relay cable 6 and the head 2 and / or the body 4, but connection without the connection portion eliminates the need for an I / O port. When the connection portion is inserted, by preparing a plurality of relay cables 6 having different lengths, the separation distance between the head 2 and the body 4 can be freely set, but the connection portion including the I / O port is required. Connection without the connection portion not only allows the connection portion of the head and the body 4 for the relay cable 6 to be miniaturized, but also eliminates the need for measures such as a protection circuit for miswiring between a pair of the head and the body 4 and the like. Further, this prevents the mismatch problem of accidental connection to different models.

[0052] Among components included in a typical triangulation sensor, one group of components such as optical components necessary for triangulation and the like and elements and a power board for such optical components are housed in the head 2, and another group of components such as a dot matrix display section such as an organic EL display section (OELD) and the like and an operation button and the like are provided in the body 4. This allows the head 2 to be miniaturized.

[0053] Figure 2The body 4 is shown. The body 4 has a long and narrow outer shape that has a slightly flat and approximately rectangular cross section, and includes a head side end 4a at one end in the long direction and an output side end 4b at the other end in the long direction. Further, the four sides of the body 4 include a relatively wide first side 4c and a narrow second side 4d that is adjacent to the first side 4c. The body 4 has a waterproof structure that includes a connection portion of the relay cable 6 and a connection portion of the output cable 8. The relay cable 6 and the output cable 8 can be cables each having a metal sheath or cables each not having a metal sheath. The relay cable 6 and the output cable 8 are preferably formed as cables each having a metal sheath to improve robustness.

[0054] The output cable 8 is connected to the body 4, and a judgment signal, i.e., an ON / OFF signal is output from the body 4 to an external environment device 10 (such as a PLC, a control portion of a separate sensor, or a control device) through the output cable 8. Figure 1 Both the relay cable 6 and the output cable 8 have flexibility that enables the relay cable 6 and the output cable 8 to be bent, and as shown in Figure 1 , the distance between the head 2 and the body 4 can be adjusted as needed by folding and bundling the relay cable 6 and holding the relay cable 6 with a cable tie B. Referring to Figure 2 , the body 4 has a groove-shaped neck N that extends in the long direction from both the head side end 4a and the output side end 4b, the groove-shaped neck N has a groove that extends in the circumferential direction, and the peripheral surface of the neck N preferably forms a circular shape. Bundling the neck N with the cable tie B allows the body 4 to be fixed to a desired installation site IL (such as a pipe in the vicinity of the head 2, etc.), for example, a site that is about 30 cm from the head 2. Further, as shown in Figure 3 , for example, the body 4 can be fixed to the cable bundle Cb with the cable tie B. In Figure 3 the example shown, the cable tie B is wrapped around the relay cable 6 and the output cable 8 to fix the body 4 to the cable bundle Cb, but the cable tie B can also be wrapped around the neck N.

[0055] As a variation of the position at which the neck N is disposed, instead of the neck N, a groove for accommodating the cable tie B can be provided near the head side end 4a and the output side end 4b of the body 4. The OELD 12 is disposed on the wide first side 4c. Further, a body operation indicator lamp 14 and a SET button 16 are arranged at one end of the first side 4c and the other end of the first side 4c, respectively, so that the OELD 12 is interposed between the body operation indicator lamp 14 and the SET button 16. The body operation indicator lamp 14 is lit or flashed in synchronization with and in the same color as the front operation indicator lamp 70 of the head 2 and the output portion operation indicator lamp 76 described later.

[0056] The body operation indicator 14 includes a green LED, which is consistent with the laser in that their respective colors are green, and green is excellent in terms of relative luminosity. A setting button 16 is provided for selecting an operation mode such as automatic threshold setting (teaching mode) or the like. An UP (up) button 18 and a DOWN (down) button 20 are arranged adjacent to each other on the narrow second side 4d, and a mode button 22 is also disposed on the narrow second side 4d. The UP button 18 and the DOWN button 20 are used, for example, for adjusting a threshold value or selecting a menu. The mode button 22 is used for switching an operation mode of the triangulation sensor 100. The setting button 16 described above can be disposed on the narrow second side 4d instead of the first side 4c.

[0057] The second side 4d on which the UP button 18, the DOWN button 20, and the mode button 22 are arranged has both ends in the long side direction protected by the raised portions Sm Figure 2 That is, the second side 4d has a basin shape surrounded by the two raised portions Sm. The upper surfaces of the UP button 18, the DOWN button 20, and the mode button 22 are located at a lower position than the raised portions Sm, so that even when any object collides with the body 4, the raised portions Sm serve as an obstacle for the object to prevent the UP button 18, the DOWN button 20, and the mode button 22 from being accidentally pressed.

[0058] As for the body operation indicator 14 described above, either one of the two raised portions Sm can be replaced with an operation indicator. Further, the two raised portions Sm can be omitted, and an operation indicator can be provided at a portion where one of the raised portions Sm is located. As described above, the raised portions Sm have a function of preventing a misoperation of accidentally pressing the UP button 18, the DOWN button 20, or the mode button 22. Instead of the raised portions Sm, a key lock function can be provided to prevent a misoperation of the operation buttons including the UP button 18, the DOWN button 20, and the mode button 22. The key lock mechanism is not limited to a physical mechanism, and can be implemented by software. For example, by refusing an operation of the operation buttons when the sensor 100 is in a predetermined operation, a misoperation can be prevented.

[0059] Figure 4This is a diagram illustrating the components arranged inside the head 2. As described above, the head 2 consists only of optical components required for triangulation, elements for these optical components, and a bare-bones power board for driving these optical components and elements. In other words, the head 2 is designed to be miniaturized to the maximum extent. This miniaturization allows for greater freedom in choosing the installation location of the head 2. Furthermore, since the body 4, which is integrally connected to the head 2 using cable 6, can be fixed to the desired location using a cable tie B, the body 4 can be installed in a location that is convenient for the user and relatively close to the head 2. This allows for the operation of the OELD 12's UP button 18 and DOWN button 20, etc., for setting judgment thresholds, etc., while viewing the OELD 12 on the body 4.

[0060] The measuring light emitted by head 2 is a green laser, described later. Compared to red laser, green laser, with its shorter wavelength, forms a smaller, more defined spot image, thus improving the accuracy of the triangulation sensor 100. As mentioned above, green is known to be superior in terms of relative luminosity. Even when power limitations are imposed on the green laser to meet safety standards (e.g., IEC, ANSI) Level 1 and Level 2 for safe use of lasers, the visibility of the green laser spot can be maintained. As mentioned above, body 4 can be placed at a desired location near head 2. As mentioned above, miniaturizing head 2 allows for increased freedom in selecting the installation location. Therefore, placing head 2 at a location suitable for measuring the object to be inspected and placing body 4 at any desired location near head 2 allows for setting tasks such as setting a judgment threshold while visually identifying the green laser spot appearing on the surface of the object to be inspected to determine if the spot position is appropriate and while observing OELD 12.

[0061] Compared to red laser sources, green laser sources typically require higher voltage. The main body 4 includes a power supply circuit 30A for generating a voltage suitable for a green laser source. Figure 12 Furthermore, a power supply circuit 78 for generating voltages suitable for other electronic components (such as the camera element 60 and the light receiving circuit 62) is provided in the head 2. The power supply circuit 30A used for the green laser light source is removed from the head 2 and provided in the body 4, thereby allowing the head 2 to be miniaturized. In addition, to further increase the freedom of mounting the head 2, in the case of miniaturization of the head 2, a housing structure that can be used for mounting using the side or back 2d of the head 2 is adopted, and the surfaces of the head 2, except for the light projection receiving surface 2a and the corner 2e where the cable 6 is located, are flat. In other words, by adopting a structure in which the head 2 does not have surfaces that serve as user interfaces other than the light projection receiving surface 2a and the corner 2e, the freedom of mounting the head 2 can be increased.

[0062] The head 2 includes a motion sensor 50 for detecting a change in the mounting position of the head 2. A typical example of the motion sensor 50 is a gyro sensor, and other examples include an acceleration sensor and a geomagnetic sensor. The motion sensor 50 is integrally mounted with the head 2. Specifically, the motion sensor 50 is assembled to the head 2 so as not to displace with respect to the head 2. This allows the motion sensor 50 to sensitively detect a shift in the optical axis caused by a change in the mounting position of the head 2 to which an external force is applied, and in turn makes it possible to issue an optical axis shift occurrence alarm.

[0063] The head 2 includes a light projecting section 52, a light projecting lens 54, a light receiving lens 56, a mirror 58, and an image pickup element 60, and these components form an optical path for triangulation. The light projecting lens 54 is composed of a collimator lens. As a modification, the light projecting lens 54 can be composed of a combination of a collimator lens and a cylindrical lens. The use of the combination of the collimator lens and the cylindrical lens has an advantage of allowing measurement accuracy to increase. The image pickup element 60 is composed of a CMOS linear image sensor, and the image pickup element 60 includes a charge storage element. The light receiving section 64 is composed of the image pickup element 60 and a light receiving circuit 62.

[0064] The light projecting section 52 is composed of a semiconductor laser light source (InGaN / GaN laser light source) that emits green laser light. The head 2 projects green laser light toward a detection region to be detected. The state of a light spot on the workpiece surface affects detection accuracy. The smaller the condensed light spot, the higher the detection accuracy. The light spot state of green laser light is superior compared to that of red laser light. It is well known that green is superior in terms of relative luminosity. The use of this characteristic makes it possible to ensure visibility of the light spot even when restrictions are imposed on the intensity and power of green laser light. A user desires to be able to confirm with the naked eye that a desired position on a workpiece is irradiated with a projected light beam, to properly perform optical axis adjustment and threshold setting, and in turn detection.

[0065] Green laser light emitted by the light projecting section 52 reaches a workpiece through the light projecting lens 54 and a light projecting window 66. Reflected light reflected from the surface of the workpiece passes through a light receiving window 67 and the light receiving lens 56, is refracted by the mirror 58, and is received by the light receiving section 64. That is, the light receiving section 64 receives green laser light reflected from a detection region on the workpiece and photoelectrically converts the green laser light into a light receiving signal. The light projecting section 52 and the light receiving section 64 are controlled by a processor 68 built in the head 2.

[0066] From Figure 4As can be seen, the head 2 has a relatively thin, approximately cuboid shape, and the light projection window 66 and the light reception window 67 are arranged on the narrow light projection reception surface 2a, and a front operation indicator lamp 70 composed of 2-color LEDs including red and green LEDs is provided between the light projection window 66 and the light reception window 67, for example. The front operation indicator lamp 70 can be illuminated or flashed in red, green, or yellow, which is a mixture of red and green.

[0067] As can be seen from Figure 1 and Figure 4 the head 2 has an approximately cuboid shape, and only the light projection reception surface 2a serves as a user interface. This structure allows the head 2 to be miniaturized. Then, a structure in which the front operation indicator lamp 70 is provided on the light projection reception surface 2a that exclusively serves as a user interface is adopted. Each surface other than the light projection reception surface 2a and the inclined corner portion 2e where the relay cable 6 is located is a flat surface, and the head 2 can be installed by using any surface other than the light projection reception surface 2a and the corner portion 2e. An operation portion or a display portion can be provided on the light projection reception surface 2a that serves as a user interface together with the front operation indicator lamp 70, or can be provided on the front operation indicator lamp 70.

[0068] In the first end 2b and the second end 2c of the head 2 in the long direction, the corner portion 2e between the second end 2c away from the light projection window 66 and the back surface 2d opposite to the light projection reception surface 2a has a chamfered shape, and the corner portion 2e is preferably an inclined surface of 45°. A hole for the relay cable 6 to pass through is formed at the corner portion 2e, and a waterproof gasket 72 prevents water from entering the hole. Inside the head 2, a 2-color LED 74 of the same color as the front operation indicator lamp 70 is provided directly adjacent to the waterproof gasket 72. The waterproof gasket 72 is composed of a light-transmitting light guide member, and a second operation indicator lamp 76 is composed of the LED 74 and the light-guiding waterproof gasket 72. The front operation indicator lamp 70 and the output portion operation indicator lamp 76 are illuminated in yellow or green in synchronization with an ON / OFF determination signal, or are flashed in red, for example, to indicate an error. The illumination color of the front operation indicator lamp 70, the output portion operation indicator lamp 76, and the operation indicator lamp 14 of the main body 2, that is, green, is the same as the green of the laser light, and green is excellent in terms of relative luminosity.

[0069] Figure 5 is a cross-sectional view of the head 2. An LED board 92 on which red and green LEDs 74 are mounted is provided at the corner portion 2e. The light-guiding material of the waterproof gasket 72 having a water-blocking ability for the relay cable 6 is preferably milky white fluorine rubber, vinyl acetate rubber, or silicone rubber. The light emitted by the red and green LEDs 74 is diffused by the light-guiding waterproof gasket 72 and brightens the light-guiding waterproof gasket 72.

[0070] During the operation of the triangulation sensor 100, the head 2 is installed in a state where the light projection receiving surface 2a and the corner 2e where the relay cable 6 is located are exposed. This not only prevents the lighting or blinking of the front operation indicator lamp 70 located on the light projection receiving surface 2a, but also prevents the output portion operation indicator lamp 76 located at the corner 2e where the relay cable 6 is located from being blocked.

[0071] In the head 2, the relay cable 6 extends from the corner 2e that is the inclined surface. Therefore, for the installation of the head 2, the head 2 can be installed by using any one of the five surfaces of the head 2 including the wide two surfaces, the back surface 2d, and the first end 2b and the second end 2c.

[0072] The distance between the head 2 and the body 4 can be adjusted as desired by folding and bundling the relay cable 6 Figure 1 ) and the place where the body 4 is installed and fixed is also determined as desired Figure 2 and Figure 3 For the installation of the body 4, a place near the head 2 is selected, and the body 4 is positioned to allow the user to easily view the OELD 12. Since the body operation indicator lamp 14 is configured on the surface on which the OELD 12 is configured, the user easily visually confirms the body operation indicator lamp 14.

[0073] During the operation of the triangulation sensor 100, a total of three operation indicator lamps (the front operation indicator lamp 70 and the output portion operation indicator lamp 76 of the head 2, and the operation indicator lamp 14 of the body 4) are placed at a place where the user can easily confirm the operation indicator lamps without moving to the case. Therefore, any one of the front operation indicator lamp 70, the output portion operation indicator lamp 76 of the head 2, or the operation indicator lamp 14 of the body 4 allows the user to confirm the operation of the triangulation sensor 100.

[0074] As described above with reference to Figure 2 , bundling the slot-like neck N of the body 4 with the bundle knot B allows the body 4 to be fixed to a desired place IL near the head 2. The body 4 has a rectangular cross section. The first side surface on which the OELD 12 is installed and the narrow second side surface on which the UP (upward) / DOWN (downward) buttons 18, 20, etc. are installed intersect at a right angle. The third side surface opposite to the first side surface and the fourth side surface opposite to the second side surface are flat surfaces and serve as installation surfaces. In the case where the third side surface and / or the fourth side surface are in contact with the installation place, the body 4 can be fixed to a relatively flat and desired place (for example, a column) near the head 2 with the bundle knot B.

[0075] Figure 6A and Figure 6B is a block diagram for describing the control system of the head 2. With reference to Figure 6AThe green laser (having a wavelength of 500 nm to 555 nm, preferably 500 nm to 532 nm) emitted by the green laser diode (LD) 520 serving as the light projection section 52 is monitored by a photodiode (monitor PD) 522, and the output current from the monitor PD 522 is fed back to the light projection control section 680 via an I / V conversion circuit 524 and an A / D conversion circuit 526 Figure 6B The green LD 520 is controlled by an LD drive circuit 530 Figure 6A , and the LD drive circuit 530 is controlled by the light projection control section 680 Figure 6B . Referring to Figure 6A , the LD drive circuit 530 includes a current control circuit 532 and a light projection switch circuit 534. A control signal is input from the light projection control section 680 Figure 6B to the current control circuit 532 Figure 6A via a D / A conversion circuit 536, and a control signal is input from the light projection control section 680 Figure 6B to the light projection switch circuit 534. This causes the green LD 520 to project laser light at predetermined intervals and with a predetermined intensity.

[0076] Referring to Figure 6A , the current flowing through the LD drive circuit 530 is monitored by an overcurrent detection circuit 538. The overcurrent detection circuit 538 includes a current detection circuit 1002 and a comparison section 1004, and when the current flowing through the LD drive circuit 530 is greater than a predetermined value, an overcurrent detection signal is supplied from the comparison section 1004 to the light projection control section 680 Figure 6B . Specifically, the comparison section 1004 converts the current flowing through the green LD 520 into a voltage, and compares this voltage with a reference voltage for overcurrent detection to determine whether the voltage based on the current flowing through the green LD 520 is equal to or less than the reference voltage for overcurrent detection. When overcurrent is detected, the light projection control section 680 Figure 6B controls to interrupt light projection or suppress overcurrent.

[0077] The position of the image of the projected light spot on the imaging element 60 is identified based on the light reception signal from the imaging element 60 Figure 6A , and the displacement of the work is measured based on the position of the projected light spot thus identified. The light reception circuit 62 Figure 6A serving as the light reception section 64 includes a CMOS control circuit 1010, an amplification circuit 1012, and a low-pass filter 1014, and the light reception signal output from the imaging element 60 is amplified by the amplification circuit 1012. Information about the received light output by the light reception section 64 is input to the processor 68 Figure 6B). The processor 68 includes a peak received light intensity detection section 682, a peak position detection section 684, a distance calculation section 686, a distance judgment section 688, and an output section 690. The peak received light intensity detection section 682 detects a peak value of the received light intensity, and inputs the peak value to the light projection control section 680 to be reflected in the light projection control. The peak position of the received light intensity is measured by the peak position detection section 684 Figure 6B ) based on the information about the received light generated by the light receiving section 64 Figure 6A ) based on the information about the received light. That is, the peak position detection section 684 measures the peak position of the received light intensity based on the information about the received light, and provides the peak position information to the distance calculation section 686. The distance calculation section 686 calculates the distance to the work based on the table 692 showing the correspondence between the peak position and the distance. The distance to the work calculated by the distance calculation section 686 is provided to the distance judgment section 688, and the distance judgment section 688 makes a judgment by comparing the distance with the judgment threshold value 694 stored in the memory. The judgment signal as a binary signal indicating ON / OFF is provided to the body 4 through the output section 690 and the communication section 80. As described later, in the body 4, a logic ON / OFF judgment signal is generated based on the output logic set by the user, and the logic ON / OFF judgment signal is output from the body 4 to the outside. As a modification, the judgment signal generated by the head 2 can be generated by the body 4. Further, the distance to the work calculated by the distance calculation section 686 is provided to the body 4 through the output section 690 and the communication section 80.

[0078] The information about the received light output from the light receiving section 64 is used to control the exposure time period of the imaging element 60 and the projection light pulse width, and thereby control is performed to project light having a laser power of level 1 or 2 that conforms to the safety standards set by the user. With reference to Figure 6B , the information about the received light output from the light receiving section 64 is input to the peak received light intensity detection section 682, and the peak received light intensity detection section 682 detects the peak received light intensity. The actual peak received light intensity is input to the comparison section 1020. In the comparison section 1020, the actual peak received light intensity is compared with a predetermined target range 1032 in the height direction of the peak received light intensity stored in the memory, and the exposure time period adjustment section 1024 adjusts the exposure time period based on the comparison. Then, the information is provided to the exposure signal generation section 1026, and the exposure signal generation section 1026 generates the exposure time period information and provides the exposure time period information to the CMOS control circuit 1010 Figure 6A ). The CMOS control circuit 1010 drives the imaging element 60 based on the exposure time period determined by the exposure time period adjustment section 1024.

[0079] With reference to Figure 6BThe comparison information generated by the comparison unit 1020 is provided to the projection light pulse width adjustment unit 1030. The projection light pulse width adjustment unit 1030 adjusts the projection light pulse width based on the comparison information and provides this information to the projection light pulse generation unit 1040. The projection light pulse generation unit 1040 determines the projection light pulse width and controls the light projection switching circuit 534 based on the projection light pulse width and a predetermined light projection interval. Figure 6A The projected light pulse width adjustment unit 1030 and the exposure time period adjustment unit 1024 serve as a feedback control unit 1032 for the peak received light intensity. The feedback control unit 1032 performs feedback control on the exposure time period, projected light pulse width, and projected photoelectric flux based on information related to the received light output by the light receiving unit 64. Two operating modes can be prepared for the green LD 520, and a first mode operating the green LD 520 at level 1 and a second mode operating the green LD 520 at level 2 can be selectively used. Preferably, the first mode can be selected for, for example, optical axis adjustment and / or inspection, and the second mode can be selected for tuning or operation. Furthermore, the projected light pulse width can be set by the user under specific constraints.

[0080] In other words, when monitoring PD 522 ( Figure 6A The target value of the received light intensity is 1042 ( Figure 6B The projection light pulse width, adjusted by the projection light pulse width adjustment unit 1030, is reflected in the signal, such that the projection light pulse width is used for feedback control, which is applied to control the amount of current supplied to the green LD 520. In other words, the monitoring received light intensity feedback control unit 1050 includes a function for monitoring the PD 522 (…). Figure 6A The comparison unit 1052 compares the actual monitored received light intensity with the target value 1042 of the monitored PD received light intensity, and provides the comparison information generated by the comparison unit 1052 to the projection photoelectric flow control unit 1054. The projection photoelectric flow control unit 1054 generates a current control signal and provides the current control signal to the current control circuit 532. Figure 6A The current control signal reduces the projected photoelectric flow rate when the actual monitored received light intensity is greater than the target value 1042, and increases the projected photoelectric flow rate when the actual monitored received light intensity is less than the target value 1042. The aforementioned overcurrent signal is provided to the fault detection unit (limiting unit) 1056, and upon receiving the overcurrent signal, the fault detection unit 1056 interrupts the projected photocurrent or controls the projected light pulse generation unit 1040 and the projected photoelectric flow rate control unit 1054 to suppress the overcurrent.

[0081] exist Figure 6BIn the present embodiment, the light projection control section 680 is shown together with the peak position distance correspondence table 692 and the distance determination threshold 694, but this is to avoid the lines becoming complicated, and it should be understood that the peak position distance correspondence table 692 and the distance determination threshold 694 are registered in the memory.

[0082] Reference Figure 6B The output of the gyro sensor serving as the above-described motion sensor 50 is input to the optical axis displacement detection section 696. The optical axis displacement detection section 696 reads the threshold value from the memory reference section 698, and when the output of the gyro sensor (motion sensor 50) is equal to or greater than the threshold value, optical axis displacement detection information is provided to the output section 690. This optical axis displacement detection information is provided to the body 4 through the communication section 80.

[0083] The head 2 includes a failure detection section 1080, and in the case where an abnormality occurs in the operation of the head 2, the front operation indicator lamp 70 and the output section operation indicator lamp 76 are driven to blink red by the indicator lamp control section 1082. Further, the indicator lamp control section 1082 provides an abnormality occurrence signal to the body 4 through the communication section 80 to cause the body operation indicator lamp 14 to blink red.

[0084] Figure 7 is a block diagram for describing the control system of the body 4. The body 4 includes the processor 24, the input circuit 26, the output circuit 28, the power supply circuit 30, and the communication section 34. Figure 8 The operation section 402 shown corresponds to the setting button 16, the UP button 18, the DOWN button 20, and the mode button 22. The user can perform tuning setting, mask setting, threshold value setting of the gyro sensor (motion sensor 50), output logic setting of the body 4, and clear input, etc. by operating the operation section 402. When optical axis displacement is detected based on the signal from the motion sensor 50, an alarm signal is generated, and this alarm signal is held until a clear instruction is given. When the user operates the operation section 402, the operation is received by the operation reception section 240, and when the user performs an operation for changing, for example, the optical axis displacement threshold value or the distance determination threshold value, the optical axis displacement threshold value or the distance determination threshold value stored in the memory 32 is updated.

[0085] The measurement information containing information on the received light received from the head 2 through the communication section 34 and the transceiver section 340 is provided to the output generation section 246 through the transceiver section 340. The output generation section 246 generates a determination ON / OFF signal based on the determination data received from the head 2 and the output logic 248 set by the user. The determination ON / OFF signal is provided to the external device through the output circuit 28 and the output cable 8.

[0086] Upon receiving the failure detection signal or the optical axis displacement detection signal, the output generation section 246 immediately provides an alarm signal to the outside through the output circuit 28. Further, the output generation section 246 provides the optical axis displacement detection information to the display control section 250, and the display control section 250 controls the drawing on the OELD 12 based on the optical axis displacement detection information. The OELD 12 displays a notification that the optical axis displacement has occurred.

[0087] The measurement information received from the head 2, which contains information on the received light with a judgment threshold, is provided to the display control section 250, and the display control section 250 controls the drawing on the OELD 12 based on the measurement information containing information on the received light. The OELD 12 displays the measurement information.

[0088] Figure 8 Examples of display on the OELD 12 when an abnormality such as optical axis displacement occurs are shown. The alarm display includes a first alarm display mode in which "misalignment detection" is displayed in characters, and a second alarm display mode in which the elapsed time from the time when the displacement amount based on the angular velocity detected by the gyro sensor is detected to be greater than or equal to the threshold value is displayed. The first alarm display mode and the second alarm display mode are preferably displayed alternately.

[0089] Figures 9 to 11 Examples of display on the OELD 12 during operation or threshold value setting are shown. During operation, a numerical value display mode ( Figure 9 ) or a bar display mode ( Figure 10 and Figure 11 ) can be selected. In the numerical value display mode, the current value (199.9 mm in the illustrated example) and the threshold value (67.8 in the illustrated example) are displayed in numerical values ( Figure 9 ). In the bar display mode, a distance mode ( Figure 10 ) or a height mode ( Figure 11 ) can be selected. In the bar display mode, a character C1 representing the head 2 is displayed. In the distance mode, the current value of the distance from the head to the workpiece is displayed in the form of a horizontal bar C3 ( Figure 10 ). In the height mode, the current value of the displacement of the workpiece with respect to the reference surface is displayed in the form of a horizontal bar C2 ( Figure 11 ). In Figure 10 and Figure 11In this case, the reference code C4 is a character including a vertical line of the letter "P" indicating the maximum value among the detection values acquired so far. Further, the reference code C5 is a character indicating a vertical line of the threshold value. When the user operates the UP / DOWN buttons 18, 20 to change the threshold setting, the threshold character (vertical line) C5 moves in response to the user's operation, and the value of the displayed threshold value changes accordingly. The user can adjust the threshold value while viewing the bar display of the current value and the display of the maximum value on the OELD 12 and confirming the position of the threshold character C5. Note that, Figure 10 and Figure 11 the numerical value "12.3" shown in

[0090] Figure 12 is a diagram for describing the power supply circuit included in the head 2 and the main body 4. The main body 4 is built-in with a power supply circuit 30. The power supply circuit 30 includes two power supply circuits 30A, 30B. One power supply circuit 30A adjusts the voltage of the power supply received from the outside and supplies the voltage thus adjusted to the other power supply circuit 30B and the head 2. The other power supply circuit 30B adjusts the voltage and supplies the voltage to the processor 24 and the head 2. In the head 2, the motion sensor (gyro sensor) 50 and the processor 68 are driven by the electric power received from the main body 4, and the green LD 520 is driven. The second power supply circuit 78 of the head 2 adjusts the voltage, and stabilizes the voltage thus adjusted by a linear adjustment section 82, and then supplies the voltage to the imaging element 60 and the light reception circuit 62.

[0091] Figure 13 is a flowchart for describing the control of the processor 68 that limits the intensity and power of the green laser-emitting LD 520 (Fig. 6). Referring to Figure 13 , in step S1, the projection light pulse generation section 1040( Figure 6B ) generates a light projection signal at a predetermined light projection interval. In the next step S2, the green LD 520 is driven at a predetermined current amount. In the next step S3, the monitoring received light intensity feedback control section 1050 in the light projection control section 680 of the processor 68 judges whether or not the monitoring PD 522( Figure 6A) whether the intensity of the received light is within a specified range. In the case where it is judged as "No", i.e., the intensity of the received light falls outside the specified range, the processing proceeds to Step S4 to judge whether the deviation has occurred continuously for at least a predetermined number of times. In the case where it is judged as "Yes" in this Step S4, i.e., the deviation has occurred continuously for at least the predetermined number of times, it is considered that some failure has occurred, and the light projection by the green LD 520 is interrupted (S5). When it is judged as "No" in Step S4, the processing proceeds to Step S6 to adjust the amount of current for controlling the green LD 520, and the processing returns to Step S2. As described in Step S3 or the like, by monitoring the intensity of the monitoring emission light at a plurality of sites, even in the case where one of them fails, it is possible to ensure the operation based on the laser level that can ensure the predetermined safety.

[0092] The above Steps S3 to S6 basically serve as a limiting section that imposes a limit on the intensity and power of the green laser light. The intensity and power of the green laser light emitted by the light projection section 52 are limited to a level that does not affect the user even when the user checks the position of the spot of the green laser light incident on the workpiece with the naked eye. This limit can be set in accordance with the safety standards "Class 1" or "Class 2". Green has a wavelength of 500 nm to 555 nm, and is excellent in the relative luminosity (bright relative luminosity and dark relative luminosity) compared to other colors. Therefore, even when the intensity and power of the green laser light are limited to the above level, it is possible to ensure the visibility of the spot.

[0093] Two kinds of operation modes can be prepared for the green LD 520, and the first mode in which the green LD 520 is operated at Class 1 and the second mode in which the green LD 520 is operated at Class 2 can be selectively used in accordance with the user's setting. Preferably, the first mode can be selected, for example, for optical axis adjustment and / or inspection, and the second mode can be selected for teaching or operation. Further, the projection light pulse width can be set by the user under certain limitations.

[0094] In the triangulation sensor 100, control is performed to keep the light reception signal within an appropriate signal strength to correctly calculate the distance from the light reception signal. Figures 14A to 14C is a graph for describing an explanation when the intensity of the received light is too high and an explanation when the intensity of the received light is too low. Figure 14A The case where the intensity of the received light is too high is shown. When the intensity of the received light exceeds the saturation point, the peak portion of the received light waveform disappears so that the position of the peak cannot be accurately grasped. Figure 14B The case where the intensity of the received light is too low is shown. When the intensity of the received light is low, the peak of the received light waveform as a whole becomes low so that the peak position cannot be accurately grasped. Reference Figure 14C, the exposure time of the image pickup element 60 is controlled by an electronic shutter (not shown). According to the present embodiment, control is performed so as to change the exposure time based on the peak light intensity of the light reception signal, to make the exposure time shorter to lower the intensity of the received light when the intensity of the received light is too high, so as to make the peak of the received light waveform lower, and to make the exposure time longer to increase the intensity of the received light when the intensity of the received light is too low, so as to make the peak of the received light waveform higher. Changing the exposure time of the image pickup element 60 changes the intensity of the light received by the image pickup element 60.

[0095] With regard to controlling the intensity of the received light to optimize the peak of the received light waveform, in addition to the exposure time described above, the received light gain of the circuit for amplifying the light reception signal and the light emission power of the green LD 520 are changed to control the intensity of the light emission signal. Preferably, the light emission power of the green LD 520 is increased to distinguish the light emission signal from the signal generated by the ambient light. Under this assumption, preferably, the peak of the received light waveform is controlled to be appropriate based on the exposure time of the image pickup element 60 and the received light gain. The advantage of the control based on the exposure time of the image pickup element 60 is that it is relatively easy to introduce the control, but in order to expand the adjustable dynamic range, it is preferable to employ a combination of the received light gain or the light emission power and the exposure time.

[0096] As described above, for a workpiece having a low reflectance, the green laser has an advantage in high relative luminance and high visibility. However, for example, for a white workpiece or a metal workpiece having a high reflectance, the user can feel that the light spot is too dazzling. Such a dazzling light spot interferes with the optical axis adjustment. From this point of view, preferably, control is performed to change the light emission power in accordance with the surface texture of the workpiece. As a specific example, Figure 15 The flowchart shown represents an example of control that changes the projection light pulse width in addition to changing the exposure time. Instead of the projection light pulse width, the current value can be changed. When the projection light pulse width is equal to or greater than the exposure time of the image pickup element 60, the detection performance of the sensor does not deteriorate.

[0097] Reference Figure 15 In step S11, the light intensity control processing is performed. Figure 16 is a flowchart for describing an example of the light intensity control processing. In Figure 16In step S111, the light projection signal is generated at a predetermined light projection interval by the projection light pulse generation section 1040. In the next step S112, the light projection section 52 is controlled in accordance with the set amount of current and the projection light pulse width. In step S113, it is determined whether the intensity of the light received by the monitoring PD 522 for feedback control of the intensity of the projection light is within a specified range, and in the case of a determination of "No", the processing proceeds to step S114 to determine whether the number of deviations from the specified range is equal to or less than a predetermined number. The predetermined number depends on the laser class regulation set by the user, and when the laser class regulation cannot be ensured, a signal to interrupt the projection light pulse is generated (S115). In the case where there is no problem in terms of the light power of the controlled green LD 520 being based on the laser class for ensuring safety, the signal to interrupt the light projection pulse can be generated only in the case where the response time cannot be ensured. In step S114, when the number of deviations from the specified range is equal to or less than the predetermined number, the determination is "Yes", and the processing proceeds to step S116 to set the amount of current for controlling the light emission.

[0098] Returning to Figure 15 the flowchart of FIG. 10, in step S12, the projection light pulse generation section 1040 Figure 6B determines whether there is a signal to interrupt the projection light pulse. In the case where there is the signal to interrupt, the processing proceeds to step S13 to interrupt the light projection. When there is no signal to interrupt the projection light pulse in step S12, the processing proceeds to step S14 to perform the overcurrent detection processing.

[0099] Figure 17 is a flowchart for describing an example of the overcurrent detection processing. In Figure 17 step S141, the current flowing through the green LD 520 is converted into a voltage, and a comparison is made between the voltage and a reference voltage for overcurrent detection to determine whether the voltage based on the current flowing through the green LD 520 is equal to or less than the reference voltage for overcurrent detection (S142). When the voltage based on the current flowing through the green LD 520 is higher than the reference voltage for overcurrent detection, the determination is "No", and the processing proceeds to step S143 to generate an overcurrent detection signal and generate a signal to interrupt the projection light pulse (S144).

[0100] Returning to Figure 15In step S15, it is judged whether there is a projection light pulse interruption signal. When there is a projection light pulse interruption signal, the processing proceeds to step S13 to interrupt the light projection. When there is no projection light pulse interruption signal, the processing proceeds to step S16 to drive the image pickup element 60 during the set timing and exposure time period, and to acquire a light reception signal from the intensity of the light received during the exposure time period (S17). Then, in the next step S18, it is judged whether the maximum value of the light reception signal falls within the target range, and when the maximum value of the light reception signal falls within the target range, it is judged "Yes", and the processing proceeds to step S19 to add the intensities of the light received by the respective light reception pixels to form a received light waveform. In the next step S20, the position of the peak of the received light waveform is calculated, the displacement (position) of the workpiece is calculated from the peak position (S21), information based on the thus calculated displacement of the workpiece is output (S22), and then the processing returns to step S11. The output in step S22 can be a case where the displacement of the workpiece is output or a case where a judgment ON / OFF signal is generated based on a comparison with a threshold value.

[0101] In step S20, the peak position of the received light waveform is calculated as follows.

[0102] (1) When the peak position can be acquired from the received light waveform, the peak position is judged to be the thus acquired peak position.

[0103] (2) When the intensity of the received light is too high and causes saturation, the peak position is estimated from the acquired received light waveform.

[0104] (3) When the peak position can be acquired in a case where the intensity of the received light is too low to fall outside the target range, the peak position is determined to be the thus acquired peak position.

[0105] (4) When the intensity of the received light is too low to prevent the peak position from being detected, it is considered that the workpiece exists at the farthest or nearest position set in advance.

[0106] When the maximum value of the light reception signal falls outside the target range in step S18, the processing proceeds to step S24 to change the exposure time and projection light pulse width settings to optimize the intensity of the received light, and then the processing returns to step S11.

[0107] Figure 18A is a diagram for describing, for example, a portion for receiving reflected light in the image pickup element 60 constituted by CMOS to be different in dependence on the distance to the workpiece. In the illustrated example, when the workpiece is located at a close distance, an image of a light spot is formed in the lower portion of the image pickup element 60 (a portion for receiving reflected light in the image pickup element 60 is different in dependence on the distance to the workpiece) (a case where the workpiece is located at a close distance) (a case where the workpiece is located at a far distance) (a case where the workpiece is located at a close distance) (a case where the workpiece is located at a far distance). Figure 18B). Furthermore, as will be described next, the image of the light spot is relatively large. On the other hand, when the work is located at the far distance, the image of the light spot is formed at the upper portion of the imaging element 60. Furthermore, as will be described next, the image of the light spot is relatively small Figure 18B As will be described later, the imaging element 60 is designed such that the groups of the pixels 60a of the imaging element 60 preferably have a width that becomes larger from the portion that receives light when the work is located at the far distance toward the portion that receives light when the work is located at the near distance. Here, the width of the pixel 60a substantially indicates the interval between two adjacent pixels 60a, i.e., the interval between the center of the first pixel and the center of the second pixel.

[0108] Figures 19A to 19D is a diagram for describing that the portion for receiving the light spot image SP in the imaging element 60 composed of a plurality of pixels 60a differs depending on the distance to the work and the size of the light spot image SP changes depending on the distance to the work. Figure 19B A case where the light spot is formed at one end of the group of the pixels 60a of the imaging element 60 when the work is located at the near distance is shown. Figure 19C A case where the light spot is formed at the middle portion of the group of the pixels 60a of the imaging element 60 when the work is located at the middle position is shown. Figure 19D A case where the light spot is formed at the other end of the group of the pixels 60a of the imaging element 60 when the work is located at the far distance is shown.

[0109] As is apparent from Figure 19B As is apparent from Figure 19D ) the light spot image SP becomes large when the work is located at the near distance and the light spot image SP becomes small when the work is located at the far distance. In the case where the pixels 60a of the imaging element 60 are arranged at equal intervals, in the illustrated example, the light is received by seven pixels 60a when the work is located at the near distance. On the other hand, the light is received by one pixel 60a when the work is located at the far distance.

[0110] In the case where the work is located at the near distance and the light representing the light spot image SP is received by a plurality of pixels 60a Figure 19B ), the number of the pixels 60a that receive the light is large and, based on the data of the light received by the plurality of pixels 60a, the received light waveform can be approximated to a curve, thereby improving the accuracy of estimating the peak position of the received light intensity. On the other hand, in the case where the work is located at the far distance and the light representing the light spot image SP is received by, for example, one pixel 60a Figure 19D), the peak position of the received light intensity cannot be estimated because the received light waveform cannot be approximated as a curve. It is desirable that the width of each light-receiving pixel 60a be smaller to cause the received light waveform to be approximated as a curve even when the work is located at a far distance. On the other hand, when the width of each light-receiving pixel 60a is made smaller, the number of pixels of the entire imaging element increases, and thus the processing load increases.

[0111] To solve this problem, preferably, the imaging element 60 mounted on the head 2 is designed so that the width of the pixel 60a varies in a manner depending on the distance to the work. Figures 20A to 20D is a conceptual diagram for describing an example in which the imaging element 60 is designed so that the width of the pixel 60a gradually decreases from the near distance side toward the far distance side. Figure 20A is an image map of the imaging element 60 having the pixels 60a arranged at unequal intervals. The size of the spot image SP formed by the imaging element 60 is determined in accordance with the detection range of the head 2. Figure 20B The spot image formation position and the spot image SP when the work is located at a near distance are shown. Figure 20C The spot image formation position and the spot image SP when the work is located at an intermediate distance are shown. Figure 20D The spot image formation position and the spot image SP when the work is located at a far distance are shown. In the illustrated example, the width of the pixel 60a is defined so that the spot image SP is received by three pixels 60a regardless of the distance to the work. This causes the peak position to be estimated by causing the received light intensity of the three pixels 60a that receive the spot image SP to be approximated as a curve regardless of the distance to the work. In addition, since many pixels 60a do not receive light, the number of pixels of the entire imaging element can be reduced, and the processing load can be reduced. This makes it possible to achieve both the peak position detection accuracy and the reduction in the processing load. In the illustrated example, the spot image SP is received by three pixels 60a. This is based on the reason that the spot image SP is better received with at least three pixels 60a to cause the received light waveform to be approximated as a curve.

[0112] Although in Figures 20B to 20D , the spot image SP is represented with a circle or an ellipse, the shape of the spot image SP is not limited to a circle or an ellipse, and can be a rectangle.

[0113] Figure 21is a block diagram for describing the structure of the light projection receiving surface 2a of the head 2. One side of the head 2 having a relatively narrow width is used as the light projection receiving surface 2a, and the light projection receiving surface includes a light guide member holding portion 79 having a light projection window 66 and a light receiving window 67, and a light diffusion member 70c that guides and diffuses outward the light of the first operation indicator lamp unit 72 located on the light projection receiving surface 2a (i.e., the front surface) of the head 2. The light diffusion member 70c is attached between the light projection window 66 and the light receiving window 67 of the light guide member holding portion 79. In Figure 21 , reference numerals 70a, 70b represent light sources of the front operation indicator lamp 70 formed as a unit, 70a represents a red LED, and 70b represents a green LED.

[0114] A waterproof gasket 84 is disposed outside the light guide member holding portion 79, and a light-transmissive cover member 86 is disposed outside the waterproof gasket 84. The light-transmissive cover member 86 is fixed by a metal cover holding member 88. The waterproof gasket 84 is compressed by engaging the metal cover holding member 88 to the first housing 2, thereby waterproofing the light projection receiving surface 2a.

[0115] The waterproof structure is substantially the same as that of the head 2, that is, the waterproof gasket 72 Figure 5 ) for the relay cable 6 and the waterproof gasket 84 for the light projection receiving surface 2a are applied to the body 4, and the waterproof structure is applied to the body 4 including the portion around the OELD 12, the operation portion 402, the connection portion of the relay cable 6 and the output cable 8.

[0116] Figure 1 , Figure 5 and Figure 21 Reference numeral Th represents a mounting through-hole. The mounting through-hole Th is a through-hole extending in a direction perpendicular to the optical axis direction of the green laser, and the head 2 is fixed at any desired place by a bolt inserted into two mounting through-holes Th extending in a direction passing through the head 2.

[0117] Figure 22is a view for describing that the relay cable 6 and the output cable 8 are connected to the body plate 36 built in the body 4 without a connection portion by soldering. Note that the reference sign C indicates a contact of the body plate 36. Specifically, the relay cable 6 is connected to a flexible substrate 38, and the flexible substrate 38 is soldered to the body plate 36. Note that the other end of the relay cable 6 is soldered to the head 2. That is, the head 2 and the body 4 are connected to each other by soldering both ends of the relay cable 6. This allows the body 4 and the head 2 to be substantially integrated with each other in terms of a circuit structure. According to the description of the output cable 8, the output cable 8 has a contact of a vertical relay member 40 soldered to the contact C of the body plate 36. This allows the total length of the body 4 to be shortened. As a modification, a connection portion can be provided at the end of the body 4 adjacent to the head 2, and the body 4 and the relay cable 6 can be connected to each other by the connection portion. Further, a connection portion can also be provided at the output side end of the body 4, and the output cable 8 can be connected to the connection portion.

[0118] Figures 23 to 26 is a view for describing a water-blocking structure of both ends of the body 4. The body 4 has caps 102 at both ends, and Figure 23 and Figure 24 shows a state in which the cap 102 adjacent to the head 2 is loosened. Figure 23 is a side view, and Figure 24 is a sectional view. Figure 25 is an enlarged view of a portion shown along Figure 24 the arrow XXV. The reference sign 104 indicates a water-blocking member, i.e., a gasket. The cap 102 is fastened, which causes the gasket 104 to be in a compressed state. Figure 26 is a sectional view corresponding to Figure 25 , which shows a state after the cap 102 is fastened. As is apparent from Figure 26 , fastening the cap 102 eliminates a gap between the cap and the body 4 and causes the gasket 104 to be in a compressed state.

[0119] In Figure 26 , the reference sign 108 indicates a wire portion. In Figure 23 and Figure 24 , a neck portion N is formed inside the cap 102 on the right side of each view in a fastened state.

[0120] <Second Embodiment Figures 27 to 31 )

[0121] The displacement sensor according to the second embodiment is an optical triangulation sensor provided with a green laser light source as in the first embodiment. The triangulation sensor 200 according to the second embodiment is composed of a head body 202 serving as a first housing and a relay portion 204 serving as a second housing, and a relay cable 210 extending from the head body 202 is integrated with the relay portion 204. Further, an external connection cable 212 extending from the relay portion 204 is also integrated with the relay portion 204. That is, both the relay cable 210 and the external connection cable 212 extend from the relay portion 204 without a connection portion.

[0122] In the triangulation sensor 200 according to the second embodiment, the relay portion 204 includes a power supply circuit and does not have a display function. Therefore, it can be said that the displacement sensor according to the second embodiment is a displacement sensor that does not have a display function. Therefore, as shown in FIG. 8, the use aspect of the triangulation sensor 200 according to the second embodiment includes an aspect in which the triangulation sensor 200 is connected to a PLC or a control device, and an aspect in which the triangulation sensor 200 is connected to a separate amplifier having a conventional display function in a case where the user needs display. Figure 27

[0123] Figure 28A Figure 28B are block diagrams for describing the structure of the head body 202 included in the second embodiment. As seen in comparison with the above-described Figure 6A Figure 6B , the structure of the head body 202 is the same as that of the head 2 included in the first embodiment, and the head body 202 is composed of the barebone assembly required for measurement using a green laser light source, like the head 2 included in the first embodiment.

[0124] As described with reference to Figure 6B in the first embodiment, the distance judging portion 688 Figure 28B generates a judgment signal that is a binary signal representing ON / OFF based on comparison with the judgment threshold value 694 stored in the memory, and provides the ON / OFF judgment signal to an external device through the output portion 690, the communication portion 80, the relay portion 204, and the external connection cable 212.

[0125] Figure 29 is a diagram for describing the power supply circuit included in the triangulation sensor 200 according to the second embodiment. The triangulation sensor 200 is driven by power supplied from an external device to which the triangulation sensor 200 is connectable, that is, a PLC, a separate amplifier, or a control device. Figure 29 ​​​An example in which the triangulation sensor 200 is connected to the separate amplifier 300 is shown. The separate amplifier 300 includes a first power supply circuit 302 and a second power supply circuit 304 that steps down the voltage generated by the first power supply circuit 302, and a processor 306 of the separate amplifier 300 is driven by the second power supply circuit 304.

[0126] The relay portion 204 included in the triangulation sensor 200 is connected to an external device such as the separate amplifier 300 by an external connection cable 212. The voltage adjusted by the first power supply circuit 302 of the separate amplifier 300 is supplied to the triangulation sensor 200 through the external connection cable 212 to drive the green LD 520. A third power supply circuit included in the relay portion 204 steps down the voltage generated by the first power supply circuit 302 to generate power for driving the processor 68 of the head body 202. The head body 202 includes a fourth power supply circuit 78, and this fourth power supply circuit 78 steps down the voltage supplied from the first power supply circuit 302. The fourth power supply circuit 78 adjusts this voltage to a voltage that drives the image pickup element 60 and the light reception circuit 62.

[0127] The relay portion 204 has an elongated cylindrical shape, and the diameter is several times larger than the relay cable 210 and the external connection cable 212. This makes the relay portion 204 substantially morphologically integrated with the relay cable 210 and the external connection cable 212. Further, the outer shape of the relay portion 204 is designed to allow morphological integration.

[0128] The relay portion 204 is connected to the relay cable 210 and the external connection cable 212 without a connection portion. The housing 220 of the relay portion 204 is made of resin. The relay portion 204 is also provided with a water-blocking structure substantially the same as that of the body 4. That is, one end of the resin housing 220 has a grommet 222 that makes the periphery of the first relay cable 210 water-tight, and the grommet 222 is compressed by a cap 224 that surrounds the grommet 222 Figure 30 ).

[0129] Reference Figure 31 According to the second embodiment, the triangulation sensor 200 can supply the distance data, the ON / OFF determination result, and the optical axis displacement information generated by the head body 202 to the separate amplifier 300, the PLC, and the control device through the external connection cable 212. That is, the triangulation sensor 200 can be used as a displacement sensor without a display function.

[0130] Although the preferred embodiment of the present application is described above, the present application is not limited to a laser displacement sensor that projects laser light. The present application is not limited by the type of light source, and is applicable to a triangulation type and a time-of-flight (TOF) type. The present application is also applicable to a light-receiving photoelectric sensor.

Claims

1. An optical displacement sensor comprising: a first housing including a transmissive window that transmits light; a light projecting section provided in the first housing and projecting measurement light toward a detection region through the transmissive window; a light receiving section provided in the first housing and photoelectrically converting the measurement light from the detection region through the transmissive window to generate a light receiving signal; a measurement section provided in the first housing and measuring a displacement of an object to be detected based on the light receiving signal generated by the light receiving section; a cable transmitting electric power to the inside of the first housing; and a second housing accommodating at least a first power supply circuit that provides electric power of a first voltage to the first housing through the cable, the second housing further including: a reception circuit that receives measurement information generated by the measurement section in the first housing; an operation section provided on one of a plurality of sides of the second housing for setting a judgment threshold; and a display section provided on a side different in a circumferential direction from the one of the plurality of sides, the display section displaying the measurement information based on the displacement measured by the measurement section and the judgment threshold indicated based on an operation of the operation section.

2. The optical displacement sensor according to claim 1, wherein the second housing has a waterproof structure, and the waterproof structure includes a grommet arranged around an end portion of the cable and a cap that deforms the grommet by compression. A protrusion is provided on the one of the plurality of sides of the second housing to prevent a misoperation on the operation section.

3. The optical displacement sensor of claim 1, wherein, 4. The optical displacement sensor according to claim 1, wherein the second housing is integrally connected to the first housing through the cable, and the second housing includes a power supply circuit.

5. The optical displacement sensor according to claim 1, wherein the light projecting section in the first housing includes a green semiconductor laser that emits green laser light as the measurement light, and the first power supply circuit in the second housing provides electric power for driving the green semiconductor laser.

6. The optical displacement sensor according to claim 5, wherein the green semiconductor laser includes gallium nitride, and the green laser light has a wavelength of 500 nm to 555 nm. the first housing includes a second power supply circuit that steps down a voltage received from the first power supply circuit.

7. The optical displacement sensor of claim 1, wherein, 8. The optical displacement sensor according to claim 7, wherein the light projecting section in the first housing includes a green semiconductor laser that emits green laser light as the measurement light, and the first power supply circuit in the second housing provides electric power for driving the green semiconductor laser.

9. The optical displacement sensor according to claim 8, wherein the green semiconductor laser includes InGaN / GaN, and the measurement light has a wavelength of 500 nm to 555 nm. ​ 10. The optical displacement sensor according to claim 6 or 8, further comprising a restriction portion in the first housing that restricts the intensity and power of the green laser in accordance with a safety standard "Class 1" or "Class 2".

11. The optical displacement sensor according to claim 1, wherein the first housing is provided with a first operation indicator that shows a comparison result generated by comparing the displacement of the object to be detected measured by the measurement portion with a judgment threshold, and the second housing is provided with a second operation indicator that is lit or blinked in synchronization with the first operation indicator and in the same color. ​ ​

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