JP2005291719A - Sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor device capable of controlling the sensing operation at high speed with high accuracy. <P>SOLUTION: This sensor device has a sensor head, a sensor controller and a communication cable for connecting them, and the sensor head includes a transmitting means for transmitting the data transmitted from a going-way line of the communication cable, a transmitting means for transmitting the data to a returning-way line of the communication cable, a sensing means capable of controlling sensing mode, and a control means for controlling the sensing mode of the sensing means and providing the sensing data created from the sensing means to the transmitting means. The sensor controller includes a transmitting means for transmitting the data to the going-way line of the communication cable, a receiving means for receiving the data transmitted from the returning-way line of the communication cable, and a control means for transmitting the control data for controlling the sensing mode to the transmitting means and processing the sensing data transmitted by the transmitting means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sensor device suitable for high-speed and high-precision sensing.

  As a displacement sensor using a two-dimensional image sensor, a sensor in which a signal processing unit and a sensor head unit are separated and independent is known (see, for example, Patent Document 1). The sensor head includes a laser diode (LD) for light projection and a CCD for light reception. A video signal generated based on a signal obtained from the CCD is sent to a signal processing unit via an electric cord. The signal processing unit includes a CPU mainly composed of a microprocessor and an FPGA (Field Programmable Gate Array) which is a programmable logic circuit. The CPU mainly performs measurement processing and display control processing. The FPGA is mainly responsible for image processing.

  When a video signal is sent from the sensor head to the upstream signal processing unit, a communication system such as LVDS (Low Voltage Differential Signaling) is employed. On the other hand, when sending a light projection control signal such as ON / OFF or a CCD control signal from the signal processing unit to the downstream sensor head, a dedicated signal line is employed instead of communication. In addition, there is a sensor in which the image sensor included in the sensor head is changed from CCD to CMOS.

  The configuration of the electric circuit of this type of conventional sensor head is shown in FIG. As shown in the figure, the sensor head circuit 500 includes an LD 520, an LED 530, a two-dimensional image sensor (CMOS) 540, an image sensor drive circuit 550, a sensor head oscillator 560, and a parallel / serial conversion circuit 570. , EEPROM 580.

  The signal processing unit (sensor controller) sends the generated DATA_OUT (sensor setting signal), LED (sensor LED control signal), LD_ON (laser control signal), and EEPROM (EEPROM control signal) via a dedicated signal line via a cable. Send to sensor head.

  The LD 520 is driven in response to LD_ON (laser control signal). In response to the LED (sensor LED control signal), the LED 530 is driven. The EEPROM 580 is read / written by EEPROM (EEPROM control signal). DATA_OUT (sensor setting signal) is sent to the image sensor drive circuit 550. The sensor setting signal is a signal for designating a pixel area to be read by the CMOS two-dimensional image sensor.

  An imaging operation in the two-dimensional imaging device 540 is performed based on a control signal supplied from the imaging device driving circuit 550, and an output obtained as a result of imaging is sent to the imaging device driving circuit 550. The image sensor drive circuit 550 generates DATA_IN (digital video signal), HD (horizontal sync signal), and VD (vertical sync signal) based on the output obtained from the two-dimensional image sensor 540. These three signals are parallel / serial converted by the LVDS serializer via the parallel / serial conversion circuit 570 and then sent to the sensor controller 1 as video signals.

The operations of the two-dimensional image sensor 540, the image sensor drive circuit 550, and the parallel / serial conversion circuit 570 described above are performed in synchronization with the clock supplied from the sensor head oscillator 560.
JP 2002-357408, especially FIG.

  By the way, in recent years, for example, the measurement objects of the displacement sensor are diversified, and it is required to cope with even one measurement object so that the accuracy is not affected by changing the measurement position. In addition, high-speed and high-precision sensing is required. Specifically, a resist coating nozzle applied to a coater that coats a resist solution on a glass substrate. A glass substrate having a metal wiring pattern is coated with a film in displacement measurement of the glass substrate surface for glass substrate spacing control. Therefore, it is required to measure the displacement of the glass surface with high accuracy. Depending on its thickness, the film may act as a low reflectance coating or as a high reflectance coating. Further, the metal wiring has a higher reflectance than the other parts. The surface reflectance of such a glass substrate varies depending on the location. On the other hand, the resist is applied at a high speed in order to increase the throughput. Therefore, the displacement sensor integrated with the nozzle moves on the glass substrate at a high speed. Therefore, the amount of reflected light received by the displacement sensor obtained from the substrate with the movement varies rapidly and greatly. Conventionally, the amount of light emitted and the amount of light such as the shutter time and gain of the image sensor are controlled according to the maximum value of the amount of received light, so the signal at low reflectivity is low and the measurement accuracy decreases. Existed. Also, in the thickness measurement of sheet-like workpieces, the measurement area moves over a wide range due to the meandering of the sheet, but in order to measure the thickness with high accuracy, displacement measurement processing is executed over a wide range with high resolution. In addition, since the amount of processing is large, high-speed measurement is difficult.

  In a conventional displacement sensor, a light projection control signal such as ON / OFF and a CCD control signal are sent from the signal processing unit to the downstream sensor head via a dedicated signal line, so that the control is not as complicated as the video signal sent upstream. However, if the communication speed is increased, noise is more likely to ride and there is a disadvantage that the control signal cannot be accurately transmitted.

  The present invention has been made paying attention to such conventional problems, and an object of the present invention is to provide a sensor device capable of controlling a sensing operation at high speed and with high accuracy.

  The sensor device of the present invention includes a sensor head, a sensor controller, and a communication cable connecting the sensor head and the sensor controller. In the sensor head, receiving means for receiving data sent by the high-speed differential transmission method through the outgoing line of the communication cable, transmitting means for sending data by the high-speed differential transmission method to the return route of the communication cable, Sensing means capable of controlling the sensing mode, and controlling the sensing mode of the sensing unit based on the control data received by the receiving unit, and transmitting sensing data generated from the sensing unit by the operation of the controlled sensing mode Head-side control means for feeding to the means. In the sensor controller, a transmission means for sending data by the high-speed differential transmission method to the outgoing line of the communication cable, a receiving means for receiving data sent by the high-speed differential transmission method through the return line of the communication cable, Controller-side control means for transmitting the control data for sensing mode control to the transmission means and processing the sensing data received by the reception means is included.

  According to such a configuration, control data from the sensor controller to the sensor head and sensing data from the sensor head to the sensor controller are exchanged at high speed and accurately by communication. Therefore, since the sensing operation can be controlled at high speed and with high accuracy, it is suitable for measuring various measurement objects. For example, with an optical displacement sensor, high-speed and high-precision sensing is possible for measuring the displacement of the glass substrate surface, measuring the thickness of the sheet-like workpiece, and the like. The high-speed differential transmission method is, for example, the LVDS method. According to such a configuration, low power consumption and low noise are realized, and highly accurate measurement is possible.

  In the sensor device of the present invention, the sensing means may include an optical displacement sensor sensing means, a visual sensor sensing means, a proximity sensor sensing means, a length measuring sensor sensing means, and an angle sensor sensing means. According to such a configuration, the sensing operation corresponding to various detection principles of the sensor can be controlled at high speed and with high accuracy.

  The sensor device of the present invention may be configured such that the sensing means includes a light projecting element and an image sensor, and the sensing mode is light emission control of the light projecting element. According to such a configuration, the sensitivity of the light projecting element can be switched and controlled with high speed and high accuracy. The control data can be a light emission control pulse signal of the light projecting element.

  The sensor device of the present invention may be configured such that the sensing means includes a light projecting element and an image sensor, and the sensing mode is setting switching control of the measurement region of the image sensor. According to such a configuration, even when the measurement position of the measurement object changes, the measurement area can be tracked at high speed. In the sensor device of the present invention, the imaging element may be a CMOS image sensor, and the light projecting element may be a laser diode.

  In the sensor device of the present invention, the sensing means is constituted by a laser diode or LED and a CMOS image sensor, and the sensing mode is the light emission control of the laser diode or LED and the setting switching control of the measurement area of the CMOS image sensor. Data can be the light emission control signal and the measurement region setting switching signal synchronized with each other. In this way, the emission control signal of the laser diode or LED and the setting switching control signal of the measurement area of the CMOS image sensor can be transmitted to the sensor head as common high-speed differential transmission method data. The signals can be transmitted in synchronization, and the light emission control of the laser diode or LED and the setting switching control of the measurement region of the CMOS image sensor can be controlled in synchronization.

  According to the present invention, since the sensing operation can be controlled at high speed and with high precision, for example, in the case of an optical displacement sensor, high speed and high precision can be used for measuring the displacement of the glass substrate surface, measuring the thickness of the sheet-like workpiece, and the like. A sensor device suitable for accurate sensing can be provided.

  In the following, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In addition, it cannot be overemphasized that the range which this invention covers is not limited to description of the following embodiment, but the range which this invention covers is specified by description of a claim.

  The sensor device of this embodiment includes a sensor head and a sensor controller connected to the sensor head via a cable. An external perspective view of the sensor controller is shown in FIG. As shown in the figure, the sensor controller 1 is configured as one unit having a case 10. The front surface 10a of the case 10 is substantially divided into two vertically, and a display unit 11 is provided in the upper region. In this example, the display unit 11 includes a segment display 11a and a liquid crystal character display 11b.

  A lower region of the front surface 10a of the case 10 is an operation unit arrangement region. In the operation portion arrangement area, an operation portion cover 12 that opens to the front with the lower edge as a fulcrum is provided. When the operation unit lid 12 is opened, various operators such as numeric keys, function keys, slide switches, and the like are arranged therein.

  Inter-unit connectors are provided on the left and right side surfaces of the case 10 (only the right side surface 10d is shown in the figure). Each of the left and right inter-unit connectors is provided with an inter-unit connector lid (only the right lid 15 is shown in the figure). In the figure, the inter-unit connector lid (right) 15 is in a closed state, and when it is slidably opened, a first port and a second port exist inside. As will be described later, these first and second ports correspond to the first port 7 a and the second port 7 b of the relay connector piece 7.

  A USB connector 13 and an RS-232C connector 14 are provided on the lower surface 10 c of the case 10. These connectors 13 and 14 are used for communication between the sensor controller 1 and a personal computer (PC). The external connection cord 3 is drawn out from the lower surface 10 c of the case 10. The external connection cord 3 includes a power line, an external input line, an external output line, and the like. These external input / output lines are connected to a programmable controller (PLC), for example. As will be described later, the case 10 can be mounted on the DIN rail 5, and the DIN rail clamper 16 is used at that time.

  FIG. 2 shows an external perspective view of the sensor controller connected state. As shown in the figure, in this example, the three sensor controllers 1a, 1b, and 1c are arranged in a horizontal row and the mounting plate in the control panel etc. via the DIN rail 5 It is attached to. A sensor head connector 8 is provided on the upper surface 10b of each case in the mounted state. As will be described later, the sensor head connector 8 is attached with a sensor head connector 4a attached to the tip of the communication cable 4 drawn from the sensor head 2.

  An external perspective view of the sensor head during sensing is shown in FIG. As shown in the figure, a communication cable 4 having a forward route and a return route is drawn out from the case 20 of the sensor head 2, and a sensor head connector 4a is attached to the tip thereof. This sensor head connector 4 a is coupled to the sensor head connector 16 of the case 10 of the sensor controller 1. Both the forward line and the return line of the communication cable 4 are twisted pair lines.

  A light emitting semiconductor laser diode (LD) and a light receiving two-dimensional imaging device (for example, a CCD image sensor, a CMOS image sensor, etc.) are provided in the case 20 of the sensor head 2. The sensor head 2 irradiates the target object 6 with laser light emitted from a semiconductor laser diode (LD) in the form of slit light. In the figure, L1 is the irradiation light of the slit light. The irradiation light image IM on the target object 6 is formed on the light receiving surface of the two-dimensional image sensor by a lens provided in the sensor head 2. In the figure, L2 is the reflected light of the slit light. Here, the light projecting optical axis and the light receiving optical axis form a predetermined angle. The longitudinal direction of the cross section of the slit light with respect to the surface perpendicular to the traveling direction of the slit light is perpendicular to the surface formed by the light projecting optical axis and the light receiving optical axis. When the distance from the sensor head 2 to the target object 6 changes, the image of the slit light on the light receiving surface of the two-dimensional image sensor moves in a direction orthogonal to the longitudinal direction of the slit light. The horizontal scanning direction of the two-dimensional image sensor is aligned with the moving direction of the slit light image. The peak position of the light intensity on the horizontal scanning line of the two-dimensional image sensor represents the distance to the target object. Since slit light is used, the distribution of distances in the longitudinal direction of the slit light can be measured all at once.

  A block diagram showing an internal configuration of the sensor controller circuit is shown in FIG. As shown in the figure, the sensor controller circuit 100 includes four systems comprising a sensor head connector 16, an inter-unit connector (right) 18a, an inter-unit connector (left) 18b, and an external I / F connector 19. Has a connector. As described above with reference to FIG. 3, the sensor head connector 16 is connected to the sensor head connector 4 a attached to the tip of the communication cable 4 drawn from the sensor head 2. Other units adjacent to the right side or left side are respectively connected to the inter-unit connector (right) 18a and the inter-unit connector (left) 18b via the relay connector piece 7 shown in FIG. The external I / F connector 19 is a general term for the USB connector 13, the RS-232C connector 14, and the external connection cord 3 shown in FIG. 1, and a personal computer (PC) or the like is connected via the external I / F connector 19. Connection to a programmable controller (PLC) or the like is made.

  The sensor controller 100 includes a sensor head I / F circuit 110, a control unit 120, an input / output I / F circuit block 150, an FPGA oscillator 160, and an FPGA-RAM 170.

  A transmission path between the FPGA 130 and the inter-unit connector (right) 18a, and the FPGA 130 between the control unit 120 and the inter-unit connector (right) 18a, and between the control unit 120 and the inter-unit connector (left) 18b. And a first data transmission path P1 including a data transmission path between the connector and the inter-unit connector (left) 18b. Further, a data transmission path is provided between the sensor head connector 16 and the sensor head I / F circuit 110, and the sensor head I / F circuit 110 and the FPGA 130 are connected between the control unit 120 and the sensor head 16. Is provided with a second data transmission path P2.

  The control unit 120 includes an FPGA 130 that is a programmable logic circuit and a CPU block 140 that controls the operation of the sensor controller. The CPU block 140 includes a microprocessor and its peripheral circuits. The FPGA 130 is an LSI capable of programming a circuit configuration by downloading (configuring) circuit data.

  The FPGA 130 pseudo-realizes an arbitrary logic circuit by a combination of a logic block, a switch matrix, and a cross point switch. The logic block implements various logics by a LUT (Look Up Table) combining a memory and a multiplexer. The switch matrix and the cross point switch make connections between the respective logical blocks, and this connection itself is also controlled by the memory. The FPGA 130 uses an I / O block for exchanging data with the outside.

  The FPGA includes an antifuse type, an EEPROM type, a flash ROM type, and an SRAM type. The antifuse type is a type in which the connection point of the circuit in the inside is made of a fuse, and an unnecessary portion is burned out to constitute a circuit, and the other is a type in which on / off data of a semiconductor switch is determined by memory data.

  The FPGA 130 of this embodiment is an SRAM type, and it is necessary to download circuit data to the FPGA chip every time the power is turned on. If an EEPROM type or flash ROM type FPGA is used instead of the SRAM type, the programmed circuit configuration can be maintained even if the power is turned off until the circuit data is erased or another circuit data is downloaded.

  In the present embodiment, an SRAM is used for the FPGA-RAM 170 with an emphasis on high speed as a working memory of an arithmetic processing circuit in the FPGA 130. As the storage means, when importance is placed on the capacity rather than the high speed, a rewritable semiconductor memory such as a flash memory, a hard disk device, or the like can be used.

  In this example, the inter-unit connectors (18a, 18b) and the first data transmission path (P1) are provided on both the left and right sides, but only one of them may be used. In particular, in a design where the data transmission direction is fixed, in the case of a model that is planned to be functionally installed at the uppermost stream or the lowermost stream of data transmission, an inter-unit connector and It is conceivable to provide a first data transmission path.

  Hereinafter, the sensor head circuit 200 and the sensor controller circuit 100 will be described in detail, and these descriptions are based on the following matters. The illustrated signal or data transmission path may represent a plurality of lines even though it is represented by a single line. The term “control signal” has a broad meaning of a signal used for controlling the operation of the circuit, and includes an enable signal, a read / write signal, an address signal, an interrupt signal, a switching signal, a timing instruction signal, and the like.

  A block diagram showing details of the sensor head circuit is shown in FIG. The sensor head circuit 200 is an electric circuit in the sensor head 2 shown in FIG. As shown in the figure, the sensor head circuit 200 includes a serial / parallel conversion circuit 210, a semiconductor laser diode (LD) 220, a light emitting diode (LED) 230, a two-dimensional image sensor 240 as a sensing means, The imaging device driving circuit 250, the sensor head oscillator 260, a parallel / serial conversion circuit 270, and an EEPROM 280 are included. The sensor head circuit 200 operates by receiving power (+ 12V, 0V) supplied from the sensor controller 1 via the communication cable 4.

  The serial / parallel conversion circuit 210 is a receiving unit, and performs LD / ON (laser control signal) by serial / parallel conversion of a setting signal and a light projection control signal sent from the sensor controller through the forward line 4b of the communication cable 4. , LED (sensor LED control signal), DATA_OUT (sensor setting signal), and EEPROM (EEPROM control signal) are generated and output.

  In response to the LD_ON (laser control signal), the LD 220 that is a light source used for sensing light projection is driven. In response to the LED (sensor LED control signal), the LED 230 which is a display (not shown) provided in the sensor head 2 is driven. The EEPROM 280 is read / written by EEPROM (EEPROM control signal). DATA_OUT (sensor setting signal) is sent to the image sensor drive circuit 250.

  The sensor setting signal includes a pixel area to be read by the CMOS two-dimensional image sensor, a shutter speed (charge accumulation time) designation, and an imaging mode in which images are taken continuously at a constant cycle or triggered by a sensor controller. It is a signal for specifying.

  In this example, a CMOS type is used for the two-dimensional image sensor 240. Note that a CCD type may be used as the two-dimensional image sensor 240. As described above with reference to FIG. 3, the light from the LD 220 is converted into slit light and then irradiated onto the target object 6. The irradiation light image IM on the target object 6 is formed on the two-dimensional image sensor 240 by a lens (not shown) provided in the sensor head. The light projecting optical axis and the light receiving optical axis form a predetermined angle.

  The longitudinal direction of the cross section of the slit light with respect to the surface perpendicular to the traveling direction of the slit light is perpendicular to the surface formed by the light projecting optical axis and the light receiving optical axis. When the distance from the sensor head to the target object changes, the image of the slit light on the two-dimensional image sensor 240 moves in a direction perpendicular to the longitudinal direction of the slit light. The horizontal scanning direction of the two-dimensional image sensor 240 is aligned with the moving direction of the slit light image. The peak position of the light intensity on the horizontal scanning line of the two-dimensional image sensor 240 represents the distance to the target object. Since slit light is used, the distribution of distances in the longitudinal direction of the slit light can be measured all at once.

  An imaging operation in the two-dimensional imaging device 240 is performed based on a control signal supplied from the imaging device driving circuit 250, and an output obtained as a result of imaging is sent to the imaging device driving circuit 250.

  The image sensor drive circuit 250 generates DATA_IN (digital video signal), HD (horizontal synchronization signal), and VD (vertical synchronization signal) based on the output obtained from the two-dimensional image sensor 240. These three signals are subjected to parallel / serial conversion via a parallel / serial conversion circuit 270 serving as a transmission means, and then sent to the sensor controller 1 via a return line 4c of the communication cable 4 as a video signal.

  The operations of the serial / parallel conversion circuit 210, the two-dimensional image pickup device 240, the image pickup device drive circuit 250, and the parallel / serial conversion circuit 270 described above are performed in synchronization with the clock supplied from the sensor head oscillator 260 as the control means. Is called. The EEPROM 280 stores model data of the sensor head.

  Next, details of the sensor controller circuit 100 side will be described. A block diagram showing details of the sensor head I / F circuit is shown in FIG. As shown in the figure, the sensor head I / F circuit 110 includes a serial / parallel conversion circuit 111, a parallel / serial conversion circuit 112, and a sensor head I / F oscillator 113.

  The serial / parallel conversion circuit 111 performs a serial / parallel conversion on a video signal sent from the sensor head 2 via the return line 4c of the communication cable 4 as a receiving means, thereby performing DATA_IN (sensing data), HD ( Horizontal sync signal) and VD (vertical sync signal) are generated and output.

  The parallel / serial conversion circuit 112 transmits DATA_OUT (sensor setting signal), LED (sensor LED control signal), LD_ON (laser control signal), and EEPROM (EEPROM control signal) sent from the control unit 120 as transmission means. By performing parallel / serial conversion, a setting signal, a light projection control signal, and the like are generated. The setting signal, the light projection control signal, and the like generated in this way are sent to the sensor head 2 via the forward line 4b of the communication cable 4.

  The power supply (+ 12V, 0V) is sent to the sensor head circuit 200 via the sensor head I / F circuit 110. The model data read from the EEPROM 280 of the sensor head circuit 200 is sent to the control unit 120 via the sensor head I / F circuit 110.

  FIG. 7 shows a signal system diagram showing a connection relationship between the FPGA and CPU and the inter-unit connector. The transmission path for inter-unit data is eight parallel data lines. Thereby, high-speed data transmission is realized.

  The inter-unit control signal includes a signal representing a unit number for specifying a unit of a communication destination (for example, a partner who requests data output). By providing a plurality of sets of transmission paths for inter-unit data and transmission paths for inter-unit control signals, it may be possible to further increase the speed of data transmission or to transmit different data in parallel.

  In this embodiment, transmission of data between units is bidirectional, but the transmission direction may be fixed, for example, the right side is dedicated to input and the left side is dedicated to output (or vice versa). If the transmission direction is determined in this way, transmission setting is facilitated when a plurality of sensor controllers are connected. The circuit in the sensor controller can be simplified.

  The inter-CPU communication is serial communication. Since the communication speed is slower than the transmission of data between units, such as the transmission of sensing data with a small amount of data, such as the value of the calculation result obtained by processing image data, and the unit number setting of the sensor controller It is suitable for communication for initial setting and various setting changes during operation. Since the communication content can be freely determined by software instead of the communication speed being slow, the communication content is highly flexible. Such communication can be performed without interfering with high-speed transmission of data between units. The transmission path for inter-CPU communication may be routed through the FPGA 130.

  A block diagram showing details of the FPGA internal circuit is shown in FIG. As shown in the figure, the FPGA 130 includes a timing conversion circuit 131, a data path switching circuit 132, an arithmetic processing circuit 133, a register 134, a clock switching circuit 135, a timing generation circuit 136, a buffer 137, and the like. It is included.

  The timing conversion circuit 131 allows the sensor controller to read data at an optimum timing while allowing a difference between the clock speed on the sensor head 2 side and the clock speed on the sensor controller 1 side. .

  The data path switching circuit 132 receives one of the data input from the timing conversion circuit 131, that is, the sensor head 2, among the inter-unit data (right), the inter-unit data (left), and the arithmetic processing circuit 133. Can output to all three. It can also be output to nowhere.

  Data input from the inter-unit data (right) can be output to both or one of the inter-unit data (left) and the arithmetic processing circuit 133, or can be output to neither. Data input from the inter-unit data (left) can be output to both or one of the inter-unit data (right) and the arithmetic processing circuit 133. Neither can be output. The data input from the arithmetic processing circuit 133 can be output to both or one of the inter-unit data (right) and the inter-unit data (left). Neither can be output.

  The register 134 is a memory used for data transmission between a circuit in the FPGA 130 or an input / output line of the FPGA 130 and the CPU bus.

  The clock switching circuit 135 selects either the clock signal output from the FPGA oscillator 160 or the inter-unit clock signal input from another sensor controller in accordance with the instruction from the CPU block 140 according to the instruction by the clock switching signal. Provided as an internal clock signal.

  The timing generation circuit 136 outputs a control signal to each of the timing conversion circuit 131, the data path switching circuit 132, and the arithmetic processing circuit 133 so that these circuits can operate at a coordinated timing. Adjust the operation.

  The content of the arithmetic processing circuit 133 is designed according to the sensing purpose. When the sensing data is image data, it is configured by combining arithmetic circuit blocks that perform noise removal, edge enhancement, gradation conversion, binarization, average value calculation, peak position extraction, area extraction, centroid position extraction, etc. . Sensing data to be calculated is not limited to image data, but may be multi-value data acquired in time series. For example, the output of a displacement sensor using PSD (Position Sensitive Device) is obtained as an analog signal that changes in time series, but noise removal is performed on data obtained by digitally converting (sampled) this signal at a constant period. You may comprise the arithmetic processing circuit which combined the arithmetic circuit block which performs feature-value extraction.

  Also in this case, since the FPGA 130 performs calculation processing by hardware wired according to the calculation contents, the calculation can be performed at a higher speed than the calculation performed by the CPU and the program. Thus, a phenomenon that occurs in a short time can be targeted for sensing.

  The calculation in the arithmetic processing circuit may be performed while using the FPGA-RAM 170 connected to the FPGA 130 as a working memory. The calculation in the arithmetic processing circuit 133 may be performed in units of a certain amount of data such as an image of one frame, for example, or may be performed continuously by using a line buffer for several scanning lines. It is also possible to perform a pipeline-type operation that sequentially processes the acquired data and outputs the results continuously.

  A block diagram showing details of the CPU block is shown in FIG. As shown in the figure, the CPU block 140 includes a CPU 141 mainly composed of a microprocessor, a serial communication I / F circuit 142, a CPU-ROM 143, and a CPU-RAM 144.

  The CPU-ROM 143 stores a program for causing the CPU to control the operation of the sensor controller and circuit data for loading into the FPGA 130 immediately after the power is turned on.

  The CPU 141, serial communication I / F circuit 142, CPU-ROM 143, and CPU-RAM 144 are connected via a CPU bus. The CPU bus is connected to both the FPGA and the input / output I / F circuit block. The serial communication I / F circuit 142 is connected to the CPU block of the sensor controller adjacent to the right side and the CPU block of the sensor controller adjacent to the left side via inter-unit connectors.

  A block diagram showing details of the input / output I / F circuit block is shown in FIG. As shown in the figure, the input / output I / F circuit block 150 includes an operation unit input circuit 151, a display unit output circuit 152, a D / A converter 153, a parallel I / F circuit 154, an RS- A 232C interface circuit 155 and a USB interface circuit 156 are included.

  The operation unit input circuit 151 functions as an interface for inputting outputs from numeric keys, function keys, and slide switches that constitute the operation unit 17. The display unit output circuit 152 functions as an interface for display data output to the display unit 11. The D / A converter 153 functions as an interface for outputting an analog signal on an output line included in the external connection cord 3. The parallel interface circuit 154 functions as an interface for exchanging parallel data with a signal line included in the external connection cord 3. The RS-232C interface circuit 155 functions as an interface for exchanging data with the RS-232C connector 14. The USB interface circuit 156 functions as an interface for exchanging data with the USB connector 13.

  The operation unit input circuit 151, display unit output circuit 152, D / A converter 153, parallel interface circuit 154, RS-232C interface circuit 155, and USB interface circuit 156 are connected to a CPU bus connected to the CPU block 140. ing. The input / output interface circuit block 150 may be provided with an interface for connecting a memory card.

  A general flowchart of the CPU 141 (during single operation) is shown in FIG. As shown in the figure, the entire process shown in the general flowchart is composed of a routine process and an interrupt process. The routine processing includes processing for loading circuit data into the FPGA 130 (step 1101), operation input processing (step 1102), external input processing (step 1103), external output processing (step 1104), and display processing (step 1105). It is out. The interrupt process includes a sensing process (step 1111).

  Routine processing starts when the power is turned on. When processing is started, circuit data is first loaded into the FPGA 130 (step 1101), operation input processing (step 1102), external input processing (step 1103), external output processing (step 1104), and display processing (step 1105). ) Is repeatedly executed, an infinite loop state is obtained.

  When processing is started by turning on the power, after loading circuit data into the FPGA 130 (step 1101), the CPU repeats an infinite loop until the power is turned off (steps 1102 to 1105). If there is an interrupt from the FPGA 130 or an external input, the CPU acquires a calculation processing result for sensing data from the FPGA 130 and executes a predetermined sensing process (step 1111).

  The circuit data is loaded into the FPGA 130 by decompressing and decompressing the circuit data compressed and stored in the CPU-ROM 143 to the CPU-RAM 144 and transferring the circuit data from the CPU-RAM 144 to the FPGA 130.

  Next, LD control will be described as an example of a sensing aspect of the sensor device of the present embodiment. FIG. 12 shows a time chart of input signals (reference symbols a and b) to the sensor head 2 and output signals (reference symbols d, e and f) from the sensor head 2.

  The sensor head oscillator 260 sends a clock CLK as indicated by reference symbol c to the two-dimensional image sensor 240, the image sensor drive circuit 250, the parallel / serial conversion circuit 270, and the serial / parallel conversion circuit 210 (see FIG. 5). . The clock frequency is 14 MHz, for example.

  The serial / parallel conversion circuit 210 performs serial / parallel conversion on a setting signal, a light projection control signal, and the like sent from the sensor controller 1, as shown by reference characters a and b in FIG. Sensor LED control signal) and LD_ON (laser control signal) are generated and output (control data).

  The image sensor drive circuit 250 generates VD (vertical synchronization signal), HD (horizontal synchronization signal), and DATA_IN (digital video signal) as indicated by reference characters d, e, and f in FIG. The two signals are subjected to parallel / serial conversion via the parallel / serial conversion circuit 270 and then sent to the sensor controller 1 as video signals (sensing data). The period of VD (vertical synchronizing signal) is 540 μs, for example, and the period of HD (horizontal synchronizing signal) is 60 μs, for example.

  In the present embodiment, the setting signal, the light projection control signal, and the like are sent from the sensor controller 1 to the sensor head 2 by serial communication via the forward line 4 b of the communication cable 4. This serial communication is a differential transmission method, and for example, LVDS is used.

  The maximum value of the ON time of LD_ON (laser control signal) is 540 × 0.8 μs (measurement cycle), and the minimum value is several tens of ns. In this way, the pulse width (ON time) of the laser diode can be switched in multiple stages according to the variation of the measurement range of the measurement target object. That is, it is possible to adjust the lighting time of the laser diode over a wide range with high accuracy, and it is possible to cope with the reflected light of various workpieces.

  Conventional LD control will be described for comparison with the LD control of the present embodiment. In the conventional sensor head shown in FIG. 23, LD_ON (laser control signal), LED (sensor LED control signal), DATA_OUT (sensor setting signal), and EEPROM (EEPROM control signal) are sent from the sensor controller via a cable to the dedicated signal line. Is sent to the sensor head. This parallel transmission is less susceptible to noise and slower in transmission speed than serial communication such as LVDS.

  FIG. 13 shows a time chart of input signals (reference symbols a, b) to the conventional sensor head and output signals (reference symbols d, e, f) from the sensor head. As indicated by reference symbol b in FIG. 13, the maximum value of the ON time of LD_ON (laser control signal) is several ms (measurement cycle), and the minimum value is several tens of μs. For this reason, the dynamic range (maximum value / minimum value) is 100 to 1000. On the other hand, the dynamic range (maximum value / minimum value) in laser control of this embodiment is tens of thousands or more.

  Sensor devices are required to have a wide dynamic range. An example of a work requiring a wide dynamic range is shown in FIG. In the coater indicated by reference symbol a in FIG. 14, a displacement sensor 1401 connected to a nozzle (not shown) moves on the glass substrate 1403 placed on a marble stage 1402, so that the glass substrate 1403 and the nozzle are connected. The gap is measured. And it is requested | required that the thickness of the coating liquid inject | emitted from a nozzle should be uniform. On the surface of the glass substrate 1403, as shown by a reference symbol b in FIG. 14, there may be a portion of the raw glass 1404, a portion 1405 that has been subjected to chrome plating, a portion 1406 with a film, and the like. The chrome-plated portion 1405 has a surface close to a mirror surface and the amount of reflected light increases, while the portion 1406 with a film has a very small amount of reflected light.

  Further, in the PWB (printed wiring board) indicated by reference numeral c in FIG. 14, the displacement sensor 1401 moves on the glass epoxy board 1408 placed on the SUS (stainless steel) stage 1407, thereby causing the glass epoxy board to move. Measurement of the thickness of the surface 1408 is required. On the surface of the glass epoxy substrate 1408, there are a copper wire 1409, a silk-printed portion 1410, a resist (transparent film) portion 1411, and the like, as indicated by reference numeral d in FIG.

  In the mold shape measurement indicated by reference symbol e in FIG. 14, the displacement sensor 1401 moves on the surface of the mold 1412, so that the thickness measurement of the recess of the mold is required. The concave portion of the mold 1412 includes a vertical surface portion 1413, an inclined surface portion 1414, and the like.

  Therefore, in order to measure various surface states in a coater, PWB, mold, etc., the dynamic range must be wide.

  As described above, the dynamic range (maximum value / minimum value) in the laser control of the present embodiment is significantly larger (tens of thousands or more) than the conventional one (100 to 1000).

  By the way, in the conventional sensor head shown in FIG. 23, by setting the laser control signal to, for example, 5 bits in parallel, it is possible to set 32 lighting times set to 1.4 times for LD lighting. It is. In this case, the ON time of LD_ON (laser control signal) has a maximum value of several ms (measurement cycle) and a minimum value of several tens ns. For this reason, the dynamic range (maximum value / minimum value) can be tens of thousands or more as in the present embodiment.

  However, in such a method, when the ON time of the LD is adjusted, the lighting time is set in increments of 1.4. Therefore, the switching range when adjusting the lighting time is also in increments of 1.4. . LD_ON (laser control signal) is darkened when the amount of received light is saturated, as indicated by reference symbol b in FIG. Or, if it is too dark, the ON time of the LD becomes 1.4 times to make it brighter. When the sensitivity is adjusted in this way, as indicated by the reference symbol f in FIG. 15, the density peak of the received light waveform changes greatly each time the adjustment is made (the shape of the mountain changes). Therefore, a measurement error occurs. In the conventional LD control method, since the adjustment switching range of the lighting time is in increments of 1.4, it is impossible to prevent the concentration peak of the received light waveform from changing greatly. In order to make a fine adjustment to change the lighting time by about 1%, it is necessary to significantly increase the number of parallel signal lines for LD control from five.

  On the other hand, in the sensor device of the present embodiment, the setting signal, the light projection control signal, etc. are sent from the sensor controller 1 to the sensor head 2 by serial communication such as LVDS via the forward line 4b of the communication cable 4. Fine adjustment of the ON time of LD_ON (laser control signal) can be performed with high accuracy. As a result, as indicated by reference symbol b in FIG. 16, fine adjustment such as setting the LD ON time to 99% or 101% of the original lighting time can be performed. At this time, as indicated by the reference symbol f in FIG. 16, the concentration peak of the received light waveform hardly changes, so that the measurement error can be reduced.

  Therefore, in the LD control of this embodiment, it is possible to achieve an effect of increasing the dynamic range and a measurement error reduction effect by fine adjustment of the LD lighting time as compared with the conventional one.

  Next, as an example of the sensing aspect of the sensor device of this embodiment, CMOS control will be described in comparison with conventional CMOS control.

  In the conventional sensor head shown in FIG. 23, LD_ON (laser control signal), LED (sensor LED control signal), DATA_OUT (sensor setting signal), and EEPROM (EEPROM control signal) are communicated from the sensor controller via a cable. The wire is sent to the sensor head.

  A timing chart of input signals to the conventional sensor head is shown in FIG. The EEPROM (EEPROM control signal) indicated by the reference symbol a and the DATA_OUT (sensor setting signal) indicated by the reference symbol b have the same timing, and it takes a time of several hundreds μs as the maximum value to send one data. . SD represents a data signal, SCL represents a clock signal, and SE represents an enable signal.

  DATA_OUT (sensor setting signal) indicated by reference sign b is a setting signal for the image sensor (CMOS). The CMOS setting data includes, for example, the X and Y coordinates of the reading start point of the rectangular field (light receiving surface) of the image sensor, the X and Y coordinates of the reading end point, the thinning intervals in the X and Y directions, the shutter speed, and the mode setting. Etc. are required, and when these are added up, a data amount of about 80 bits is obtained. Since it takes several hundreds of μs to send 1-bit data, conventionally, several tens of ms were required to send all CMOS setting data.

  A timing chart of an input signal to the sensor head of this embodiment is shown in FIG. DATA_OUT (sensor setting signal) indicated by reference symbol b requires several hundreds of ns to send one data (one bit). Accordingly, in order to send all the CMOS setting data (80 bits), it takes a time of several tens of μs. As a result, a speed approximately 1000 times that of the conventional CMOS control can be realized.

  Hereinafter, an example of a measurement method (coater, thickness measurement) realized by performing CMOS control at high speed will be described.

  First, it is assumed that a coating liquid (resist liquid) is applied to a glass substrate with a table coater. In this case, in order to uniformly apply the resist solution to the glass substrate while measuring the thickness of the glass substrate placed on the marble stage, the operation is roughly divided into four steps.

  First, in the first step, as shown in FIG. 19A, a glass substrate 1904 is placed on a marble stage 1903, and a distance to the stage 1903 is measured by a displacement sensor 1902 connected to a nozzle 1901. And reset the zero point position. In this case, since the stage 1903 is marble, the stage surface has a spotted pattern. Therefore, the spot pattern is measured on an average by a wide line beam (irradiation light image IM of slit light). A captured image by the CMOS at this time is shown in FIG. 2001 shown in the figure represents a rectangular field (light-receiving surface) of the two-dimensional image sensor. At this time, the measurement region 2002 is the same as the visual field. Reference numeral 2003 represents an irradiation light image.

  In the second step, as shown in FIG. 19B, the displacement sensor 1902 connected to the nozzle 1901 is moved to the end of the glass substrate 1904 to measure the glass surface. In this case, since the surface of the glass substrate 1904 is uniform, measurement is performed with a narrow line beam. In the third step, the height of the nozzle 1901 is initialized based on the measurement result of the second step. A captured image corresponding to the second step and the third step is shown in FIG. The measurement region 2002 is the same as the field of view in the displacement direction, and is set only at the center of the field of view in the line direction (extending direction of the irradiation light image) perpendicular to the field of view.

  In the fourth step, as shown in FIG. 19C, feedback control is performed on the glass surface displacement measurement result, and the resist solution is applied while adjusting the height of the nozzle 1901. In this case, since high-speed sampling is required, measurement is performed in a minute region. That is, as shown in FIG. 20C, the measurement region 2002 is set only in the center portion of the field of view in both the displacement direction and the line direction (extending direction of the irradiation light image).

  As described above, the line beam width and the measurement region differ depending on the operation step. Conventionally, each of (1) measuring both marble and glass with high accuracy, (2) having a range capable of measuring the thickness of glass, (3) reducing measurement time (particularly the fourth step) A point is desired. According to the sensor device of the present embodiment, different settings can be switched at high speed depending on the operation step, and the above-described demand can be satisfied.

  Next, CMOS high-speed control in measuring the thickness of a sheet-like workpiece will be described. Here, the sheet-like workpiece is assumed to be a multilayer ceramic capacitor, a building material, a sandpaper, or the like. As shown in FIG. 21, the displacement sensors 2101 and 2102 with the laser emission surfaces of the sensor heads facing each other are arranged up and down, and the thickness of the sheet-like workpiece 2105 sent out between the rollers 2103 and 2104 is determined by the displacement sensor 2101. , 2102. At this time, the distance X between the displacement sensors 2101 and 2102 is measured in advance, and the distance Y1 from the displacement sensor 2101 to the sheet-like workpiece 2105 and the distance Y2 from the displacement sensor 2102 to the sheet-like workpiece 2105 are measured. The thickness D of the sheet-like workpiece is obtained by the following equation (1).

  D = X− (Y1 + Y2) (1)

  In this case, for example, the sheet-like work 2105 is cut and then laminated, and after each layer is attached, it is coated to become a product. Therefore, an error in the thickness of each sheet-like workpiece 2105 is reflected in the product. Therefore, high accuracy is required for thickness measurement of one sheet-like workpiece. On the other hand, the sheet-like workpiece 2105 fed between the rollers 2103 and 2104 slowly meanders up and down between the rollers 2103 and 2104 and the displacement sensors 2101 and 2102. In the conventional sensor head, DATA_OUT (sensor setting signal) is sent to the sensor head by parallel transmission from the sensor controller via a cable together with LD_ON (laser control signal) and the like. Is vulnerable to noise and has a low transmission rate. Therefore, the setting of the measurement area on the CMOS cannot follow the upper and lower meanders of the sheet-like work 2105, and the measurement error cannot be reduced.

  On the other hand, in the present embodiment, the setting signal, the light projection control signal, and the like are sent from the sensor controller to the sensor head 2 through serial communication such as LVDS via the forward line 4b of the communication cable 4. Therefore, even when the sheet-like workpiece 2105 meanders up and down between the rollers 2103 and 2104 and the displacement sensors 2101 and 2102, as shown in FIG. 22, the variation in the measured displacement of the sheet-like workpiece (measurement target object). The measurement area can be moved by following it.

  That is, when the sheet-like workpiece 2105 meanders upward, as shown in FIG. 22A, the irradiation light image 2202 is positioned on the left side (displacement direction near) of the visual field 2201 in the visual field 2201 of the upper displacement sensor 2101. To do. At this time, the measurement region 2203 is set as a partial region of the visual field 2201 including the irradiation light image 2202. On the other hand, in the visual field 2204 of the lower displacement sensor 2102, the irradiation light image 2205 is located on the right side (displacement direction far) of the visual field 2204. At this time, the measurement region 2206 is set as a partial region of the visual field 2201 including the irradiation light image 2205.

  When the sheet-like workpiece 2105 does not meander up and down, as shown in FIG. 22B, in the field 2201 of the upper displacement sensor 2101, the irradiation light image 2202 is the center (center in the displacement direction) of the field 2201. Located in. At this time, the measurement region 2203 is set as a partial region of the visual field 2201 including the irradiation light image 2202. Similarly, in the visual field 2204 of the lower displacement sensor 2102, the irradiation light image 2205 is located at the center (center in the displacement direction) of the visual field 2204. At this time, the measurement region 2206 is set as a partial region of the visual field 2201 including the irradiation light image 2205.

  Further, when the sheet-like workpiece 2105 meanders downward, as shown in FIG. 22C, the irradiation light image 2202 is positioned on the right side (displacement direction far) of the visual field 2201 in the visual field 2201 of the upper displacement sensor 2101. To do. At this time, the measurement region 2203 is set as a partial region of the visual field 2201 including the irradiation light image 2202. On the other hand, in the visual field 2204 of the lower displacement sensor 2102, the irradiation light image 2205 is located on the left side (displacement direction near) of the visual field 2204. At this time, the measurement region 2206 is set as a partial region of the visual field 2201 including the irradiation light image 2205.

  The sensor device according to the present embodiment can change the measurement area of the CMOS at high speed according to the amount of meandering of the sheet-like workpiece 2105, and therefore can cope with meandering of the sheet-like workpiece 2105. Therefore, the thickness error of one sheet-like workpiece can be reduced, and the thickness error of a product in which the sheet-like workpiece is laminated can be greatly reduced.

  The sensor device of the above embodiment has been described as a displacement sensor as an example. However, the present invention is not limited to this, and may be, for example, a visual sensor, a proximity sensor, a length sensor, an angle sensor, or the like. Good.

  As described above, according to the sensor device of the present embodiment, data transmission from the sensor head to the sensor controller and from the sensor controller to the sensor head is bidirectional serial communication. Therefore, for example, in the case of an optical displacement sensor, there is an advantage that the light projecting element and the image sensor provided in the sensor head can be controlled with high speed and high accuracy.

It is an external appearance perspective view of a sensor controller. It is an external appearance perspective view of a sensor controller continuous state. It is an external appearance perspective view of the sensor head during sensing. It is a block diagram which shows the internal structure of a sensor controller circuit. It is a block diagram which shows the detail of a sensor head circuit. It is a block diagram which shows the detail of a sensor head interface circuit. It is a signal system diagram which shows the connection relation of FPGA and CPU, and an inter-unit connector. It is a block diagram which shows the detail of an FPGA internal circuit. It is a block diagram which shows the detail of CPU block. It is a block diagram which shows the detail of an input / output interface circuit block. It is a general flowchart of CPU (at the time of a single operation). It is a time chart of the input-output signal of the sensor head of this embodiment. It is a time chart of the input / output signal of the conventional sensor head. It is explanatory drawing of the usage pattern which requires a dynamic range. It is explanatory drawing of the conventional LD control. It is explanatory drawing of LD control of this embodiment. It is a time chart of the input signal to the conventional sensor head. It is a time chart of the input signal to the sensor head of this embodiment. It is explanatory drawing of the measurement of a glass substrate. It is explanatory drawing of the captured image by CMOS. It is explanatory drawing of thickness measurement of a sheet-like workpiece. It is explanatory drawing of the captured image in thickness measurement. It is a block diagram which shows the detail of the conventional sensor head circuit.

Explanation of symbols

1, 1a, 1b, 1c Sensor controller 2 Sensor head 3 External connection cord 4 Communication cable 4a Sensor head connector 5 DIN rail 6 Target object 7 Relay connector piece 7a First port (right)
7b Second port (right)
DESCRIPTION OF SYMBOLS 8 Sensor head connector 10 Case 10a Front 10b Upper surface 10c Lower surface 11 Display part 11a Segment display 11b Liquid crystal type character display 12 Operation part cover 13 USB connector 14 RS-232C connector 15 Inter-unit connector cover (right)
16 DIN rail clamper 17 Operation unit 18a Inter-unit connector (right)
18b Connector between units (left)
20 Case 100 Sensor controller circuit 110 Sensor head interface circuit 111 Serial / parallel conversion circuit 112 Parallel / serial conversion circuit 113 Sensor head interface oscillator 120 Control unit 130 FPGA
131 Timing conversion circuit 132 Data path switching circuit 133 Arithmetic processing circuit 134 Register 135 Clock switching circuit 136 Timing generation circuit 137 Buffer 140 CPU block 141 CPU
142 Serial Communication Interface Circuit 143 CPU-ROM
144 CPU-RAM
150 I / O Interface Circuit Block 151 Operation Unit Input Circuit 152 Display Unit Output Circuit 153 D / A Converter 154 Parallel Interface Circuit 155 RS-232C Interface Circuit 156 USB Interface Circuit 160 FPGA Oscillator 170 FPGA-RAM
200 Sensor Head Circuit 210 Serial / Parallel Conversion Circuit 220 Semiconductor Laser Diode (LD)
230 Light Emitting Diode (LED)
240 Two-dimensional image sensor 250 Image sensor driving circuit 260 Sensor head oscillator 270 Parallel / serial conversion circuit 280 EEPROM
L1 Irradiation light of slit light L2 Reflected light of slit light IM Irradiation light image of slit light P1 First data transmission path P2 Second data transmission path

Claims (8)

Having a sensor head, a sensor controller, and a communication cable connecting the sensor head and the sensor controller;
The sensor head
Receiving means for receiving data sent by the high-speed differential transmission method through the outgoing line of the communication cable;
A transmission means for sending data to the return line of the communication cable by a high-speed differential transmission method;
Sensing means capable of controlling the sensing mode;
A head-side control unit that controls the sensing mode of the sensing unit based on the control data received by the receiving unit, and that provides the transmission unit with sensing data generated from the sensing unit in the controlled sensing mode operation; Is included,
The sensor controller
A transmission means for sending data to the outgoing line of the communication cable by a high-speed differential transmission method;
Receiving means for receiving data sent by the high-speed differential transmission method through the return line of the communication cable;
Controller-side control means for transmitting control data for sensing mode control to the transmission means and processing the sensing data received by the reception means,
A sensor device.   The sensing means includes sensing means for an optical displacement sensor, sensing means for a visual sensor, sensing means for a proximity sensor, sensing means for a length measuring sensor, and sensing means for an angle sensor. Sensor device.   The sensor device according to claim 1, wherein the sensing means includes a light projecting element and an image sensor, and the sensing mode is light emission control of the light projecting element.   The sensor device according to claim 1, wherein the sensing means includes a light projecting element and an image sensor, and the sensing mode is setting switching control of a measurement region of the image sensor.   The sensor device according to claim 3 or 4, wherein the image sensor is a CMOS image sensor.   5. The sensor device according to claim 3, wherein the light projecting element is a laser diode.   The sensor device according to claim 3, wherein the control data is a light emission control pulse signal of the light projecting element.   The sensing means is constituted by a laser diode or LED and a CMOS image sensor, and the sensing mode is light emission control of the laser diode or LED and setting switching control of the measurement region of the CMOS image sensor, and the control data are synchronized with each other. The sensor device according to claim 1, wherein the sensor device is a light emission control signal and the measurement region setting switching signal.

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