Cutting blade detection mechanism

Abstract

To provide a cutting blade detecting mechanism that can suppress accuracy in detecting a condition of a cutting blade from deteriorating.SOLUTION: A cutting blade detecting mechanism 1 comprises: a plurality of light emitting bodies 10; a plurality of light receiving bodies 20; photoelectricity converters 30 that convert light 13 received by the light receiving bodies 20 to signals 31; selectors 60, arranged on circuits 50 through which signals 31 and 41 are transmitted, which select the circuits 50 through which output of the inputted signals 41 is stopped; and a control unit 170. The control unit 170 comprises: a circuit identifying part 172 that identifies a plurality of routes 50-1 through which the signals 31 and 41 are transmitted in a predetermined period of time out of the circuits 50; and a selector control part 173 that makes the selectors 60 stop output of the signals 41 through the circuits 50-1 other than at least one circuit 50-2 close to a cutting edge 124 of a cutting blade 121, of the plurality of circuits 50-1 identified by the circuit identifying part 172.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a cutting blade detection mechanism for detecting the state of a cutting blade equipped in a cutting device that cuts wafers such as semiconductor wafers. [Background Art]

[0002] To singulate a semiconductor wafer into individual chips, a cutting device generally called a dicer is normally used. This cutting device is provided with a cutting blade detection mechanism for detecting the replacement timing of the annular cutting edge of a cutting blade whose diameter has decreased due to wear and for detecting chipping of the annular cutting edge (see, for example, Patent Document 1 and Patent Document 2).

[0003] The aforementioned cutting blade detection mechanism comprises a blade insertion portion into which the annular cutting edge of the cutting blade is inserted, and a plurality of light emitters and light receivers (both of which are optical fibers) arranged opposite each other across the blade insertion portion. This cutting blade detection mechanism detects the state of the annular cutting edge of the cutting blade positioned in the blade insertion portion between the light emitter and the light receiver, by having the light receiver receive the light emitted from the light emitter, and converting the received light into a voltage corresponding to the amount of the light received by the light receiver. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2010-141009 [Patent Document 2] Japanese Patent No. 5236918 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] However, the cutting blade detection mechanisms described in Patent Document 1, Patent Document 2 and the like mentioned above perform detection of the cutting edge during cutting, which poses a problem that cutting water generated during cutting scatters between the light emitter and the light receiver, thereby reducing detection accuracy.

[0006] The objective of the present invention is to provide a cutting blade detection mechanism that can suppress a decrease in the accuracy of detecting the state of the cutting blade. [Means for solving the problem]

[0007] To solve the above-mentioned problems and achieve the objective, the cutting blade detection mechanism of the present invention comprises: a plurality of light-emitting elements arranged adjacent to each other in series in the radial direction of the cutting blade on one side in the rotation axis direction of the cutting blade, which has an annular cutting edge for cutting a workpiece held on a chuck table that holds a workpiece; a plurality of photodetectors disposed on the other side in the rotation axis direction of the cutting blade, facing the plurality of light-emitting elements, and receiving light irradiated by the light-emitting elements; and a photoelectric converter that converts the light received by the plurality of photodetectors into a signal of a voltage value corresponding to the amount of light. Control means and A cutting blade detection mechanism for a cutting device comprising the signal output from the photoelectric converter The control means A selector is located on the transmission circuit and selects a circuit that stops the output of the input signal. Ta Yes, The photoelectric converters and circuits are provided in the same number as the light emitters and light receivers, and each circuit corresponds to each photoelectric converter. The control means includes a circuit identification unit that identifies a circuit that transmits the signal from the photoelectric converter for a predetermined period of time, When the circuit identification unit identifies multiple circuits that transmit the signal from the photoelectric converter, The device comprises a selector control unit that controls the selector to stop the output of the signal from all circuits except at least one circuit among a plurality of circuits identified by the circuit identification unit that is closer to the cutting edge of the cutting blade, thereby reducing the influence of variations due to the amount of light received by each of the plurality of photodetectors and enabling high-precision detection of the cutting blade.

[0008] In the cutting blade detection mechanism, the control means may further include a light emission stop unit that stops the light emission from the light emitter connected to at least one circuit other than the circuit closest to the cutting edge of the cutting blade among the circuits identified by the circuit identification unit. [Effects of the Invention]

[0009] This invention has the effect of suppressing a decrease in the accuracy of detecting the state of the cutting blade. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a perspective view showing an example of the configuration of a cutting device equipped with a cutting blade detection mechanism according to Embodiment 1. [Figure 2] Figure 2 is a perspective view of the cutting unit of the cutting apparatus shown in Figure 1. [Figure 3] Figure 3 is a partial cross-sectional front view showing the configuration of the cutting blade detection mechanism of the cutting device shown in Figure 1. [Figure 4] Figure 4 shows the light-emitting element and light-receiving element of the cutting blade detection mechanism shown in Figure 3. [Figure 5] Figure 5 is a block diagram showing the configuration of the cutting blade detection mechanism shown in Figure 3. [Figure 6] Figure 6 is a block diagram showing the state in which the selector control unit of the cutting blade detection mechanism shown in Figure 5 has stopped the output of all circuits except the one closest to the tip of the cutting edge, based on the circuit identification unit's identification of the circuits. [Figure 7] Figure 7 is a block diagram showing the state in which the selector control unit of the circuit identification unit of the cutting blade detection mechanism according to Embodiment 2 has stopped the output of all circuits except the one closest to the tip of the cutting blade. [Modes for carrying out the invention]

[0011] Embodiments for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by those skilled in the art, and those that are substantially the same. In addition, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configurations can be made without departing from the spirit of the present invention.

[0012] [Embodiment 1] A cutting blade detection mechanism for a cutting device according to Embodiment 1 of the present invention will be described based on the drawings. Figure 1 is a perspective view showing an example of the configuration of a cutting device equipped with the cutting blade detection mechanism according to Embodiment 1. Figure 2 is a perspective view of the cutting unit of the cutting device shown in Figure 1. Figure 3 is a front view showing a partial cross-section of the configuration of the cutting blade detection mechanism of the cutting device shown in Figure 1. Figure 4 is a diagram showing the light emitter and light receiver of the cutting blade detection mechanism shown in Figure 3. Figure 5 is a block diagram showing the configuration of the cutting blade detection mechanism shown in Figure 3. Figure 6 is a block diagram showing the state in which the selector control unit of the circuit identification unit of the cutting blade detection mechanism shown in Figure 5 has stopped the output of all circuits except the one closest to the tip of the cutting blade.

[0013] (workpiece) The cutting blade detection mechanism 1 of the cutting apparatus according to Embodiment 1 constitutes the cutting apparatus 100 shown in Figure 1. The cutting apparatus 100 shown in Figure 1 is a processing apparatus that cuts a workpiece 200. In Embodiment 1, the workpiece 200 to be processed by the cutting apparatus 100 is a wafer such as a disc-shaped semiconductor wafer or optical device wafer with a substrate of silicon, sapphire, gallium arsenide, or SiC (silicon carbide), etc. The workpiece 200 has a device 203 formed in a grid-like region partitioned by a plurality of division lines 202 formed in a grid pattern on the surface 201.

[0014] Device 203 is, for example, an integrated circuit such as an IC (Integrated Circuit) or LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor), a MEMS (Micro Electro Mechanical Systems), or a memory (semiconductor memory device).

[0015] In Embodiment 1, the workpiece 200 is supported by the annular frame 206, wherein a disc-shaped adhesive tape 205 having a larger diameter than the workpiece 200 is adhered to a back surface 204 on the reverse side of a front surface 201 of the workpiece 200, and an annular frame 206 is adhered to an outer edge of the adhesive tape 205.

[0016] In Embodiment 1, the workpiece 200 is a wafer such as a semiconductor wafer or an optical device wafer. However, the present invention is not limited to workpieces being wafers, and may be various workpieces such as package substrates like ceramic capacitor substrates and CSP (Chip Size Package) substrates, for example.

[0017] (Cutting Apparatus) The cutting apparatus 100 shown in FIG. 1 is a processing apparatus that holds a workpiece 200 on a chuck table 110 and cuts the workpiece along planned dividing lines 202 with a cutting blade 121. As shown in FIG. 1, the cutting apparatus 100 includes: a chuck table 110 that suction-holds the workpiece 200 on a holding surface 111 thereof; a cutting unit 120 that cuts the workpiece 200 held by the chuck table 110 with the cutting blade 121; an imaging unit 130 that images the workpiece 200 held by the chuck table 110; and a control unit 170 serving as a control means.

[0018] The cutting apparatus 100 further includes a moving unit 140 that moves the chuck table 110 relatively to the cutting unit 120. The moving unit 140 includes: an X-axis moving unit 141 that processes and feeds the chuck table 110 in an X-axis direction parallel to the horizontal direction; a Y-axis moving unit 142 that indexes and feeds the cutting unit 120 in a Y-axis direction parallel to the horizontal direction and perpendicular to the X-axis direction; a Z-axis moving unit 143 that cuts and feeds the cutting unit 120 in a Z-axis direction parallel to the vertical direction perpendicular to both the X-axis direction and the Y-axis direction; and a rotary moving unit 144 that rotates the chuck table 110 around an axis center parallel to the Z-axis direction.

[0019] The X-axis movement unit 141 is installed on the main body 101 of the cutting device 100. The X-axis movement unit 141 moves the chuck table 110 in the X-axis direction, which is the machining feed direction, thereby feeding the chuck table 110 and the cutting unit 120 relatively along the X-axis direction. The Y-axis movement unit 142 and the Z-axis movement unit 143 are installed on a support frame 102 that is erected from the main body 101. The Y-axis movement unit 142 moves the cutting unit 120 in the Y-axis direction, which is the indexing feed direction, thereby feeding the chuck table 110 and the cutting unit 120 relatively along the Y-axis direction. The Z-axis movement unit 143 moves the cutting unit 120 in the Z-axis direction, which is the in-cut feed direction, thereby feeding the chuck table 110 and the cutting unit 120 relatively along the Z-axis direction. The rotational movement unit 144 is moved in the X-axis direction together with the chuck table 110 by the X-axis movement unit 141.

[0020] The X-axis movement unit 141, Y-axis movement unit 142, and Z-axis movement unit 143 each include a well-known ball screw rotatably mounted around its axis, a well-known motor that rotates the ball screw around its axis to move the chuck table 110 or cutting unit 120 in the X-axis, Y-axis, or Z-axis direction, and a well-known guide rail that supports the chuck table 110 or cutting unit 120 so that it can move in the X-axis, Y-axis, or Z-axis direction. The rotary movement unit 144 includes a well-known motor, etc., that rotates the chuck table 110 around its axis.

[0021] The chuck table 110 is disc-shaped, and its holding surface 111 for holding the workpiece 200 is made of porous ceramic or the like. The chuck table 110 is also provided to move freely in the X-axis direction by an X-axis movement unit 141 across the machining area below the cutting unit 120 and the loading / unloading area where the workpiece 200 is loaded and unloaded, separated from below the cutting unit 120, and is also provided to rotate freely around an axis parallel to the Z-axis direction by a rotational movement unit 144.

[0022] The chuck table 110 has a holding surface 111 connected to a vacuum suction source (not shown), and the workpiece 200 placed on the holding surface 111 is held in place by suction from the vacuum suction source. In Embodiment 1, the chuck table 110 holds the workpiece 200 by suction from the back surface 204 via adhesive tape 205. In addition, as shown in Figure 1, multiple clamping parts 112 for clamping the annular frame 206 are provided around the chuck table 110.

[0023] The cutting unit 120 is a machining unit to which an annular cutting blade 121 can be attached to the tip of a spindle 123. The cutting unit 120 is provided to move freely in the Y-axis direction by a Y-axis movement unit 142 and also moves freely in the Z-axis direction by a Z-axis movement unit 143 relative to the workpiece 200 held in the chuck table 110. The cutting unit 120 allows the cutting blade 121 to be positioned at any position on the holding surface 111 of the chuck table 110 by the X-axis movement unit 141, the Y-axis movement unit 142 and the Z-axis movement unit 143.

[0024] As shown in Figure 1, the cutting unit 120 includes a cutting blade 121, a spindle housing 122 that is movable in the Y-axis direction and the Z-axis direction by a Y-axis movement unit 142 and a Z-axis movement unit 143, a spindle 123 that is rotatably mounted in the spindle housing 122 around its axis, and a spindle motor (not shown) that rotates the spindle 123 around its axis.

[0025] The cutting blade 121 is an extremely thin cutting wheel having a substantially ring shape. In Embodiment 1, as shown in Figures 2 and 3, the cutting blade 121 comprises an annular cutting edge 124 for cutting the workpiece 200 held on the chuck table 110, and an annular base 125 that supports the cutting edge 124 on its outer edge and is detachably mounted on the spindle 123. The cutting edge 124 is made of abrasive grains such as diamond or CBN (Cubic Boron Nitride) and a bonding material (binder) such as metal or resin, and is formed to a predetermined thickness. In this invention, the cutting blade 121 may also be a so-called washer blade consisting only of the cutting edge 124. During cutting of the workpiece 200, a part of the cutting edge 124 may chip off.

[0026] The spindle housing 122 is supported so as to be movable in the Z-axis direction by the Z-axis movement unit 143, and is also supported so as to be movable in the Y-axis direction by the Y-axis movement unit 142 via the Z-axis movement unit 143. The spindle housing 122 houses the portion of the spindle 123 excluding the tip and a spindle motor (not shown), and supports the spindle 123 so as to be rotatable around its axis.

[0027] The spindle 123 has a cutting blade 121 mounted at its tip. The spindle 123 is rotated around its axis by a spindle motor (not shown), and its tip protrudes from the tip surface of the spindle housing 122. The tip of the spindle 123 is gradually tapered towards the tip, and the cutting blade 121 is mounted thereon. The axes of the spindle 123 and the cutting blade 121 of the cutting unit 120 are parallel to the Y-axis direction. That is, the cutting blade 121 of the cutting unit 120 is rotated around its axis by the spindle motor.

[0028] Furthermore, as shown in Figure 2, the cutting unit 120 includes a blade cover 126 mounted on the tip surface of the spindle 123 and a cutting fluid nozzle 127 that supplies cutting fluid to the cutting blade 121.

[0029] The blade cover 126 covers at least the upper part of the cutting blade 121. The blade cover 126 is fixed to the front end of the spindle housing 122.

[0030] The cutting fluid nozzle 127 supplies cutting fluid to the cutting blade 121 when the cutting blade 121 cuts the workpiece 200 held on the holding surface 111 of the chuck table 110. As shown in Figure 2, the cutting fluid nozzle 127 comprises a shower nozzle 128 and a pair of blade nozzles 129.

[0031] Nozzles 128 and 129 are attached to the blade cover 126 and are supplied with cutting fluid from a cutting fluid source (not shown). The shower nozzle 128 has a nozzle facing the tip of the cutting edge 124 of the cutting blade 121 in the X-axis direction and supplies cutting fluid from the nozzle to the tip of the cutting edge 124 of the cutting blade 121 during cutting.

[0032] The blade nozzles 129 extend parallel to the X-axis direction and are spaced apart from each other in the Y-axis direction. The blade nozzles 129 position the lower end of the cutting edge 124 of the cutting blade 121 between them and have nozzles (not shown) facing the lower end of the cutting edge 124 of the cutting blade 121. The blade nozzles 129 supply cutting fluid from the nozzles to the lower end of the cutting edge 124 of the cutting blade 121 during cutting.

[0033] The imaging unit 130 is fixed to the cutting unit 120 so as to move integrally with the cutting unit 120. The imaging unit 130 includes an image sensor that captures the area to be divided of the workpiece 200 held on the chuck table 110 before cutting. The image sensor is, for example, a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary MOS) image sensor having multiple pixels. The imaging unit 130 captures the surface 201 of the workpiece 200 held on the chuck table 110 with the image sensor through the objective lens.

[0034] The imaging unit 130 photographs the workpiece 200 held on the chuck table 110 to acquire an image for performing alignment, which involves positioning the workpiece 200 and the cutting blade 121, and outputs the acquired image to the control unit 170.

[0035] Furthermore, the cutting device 100 includes an X-axis position detection unit (not shown) for detecting the X-axis position of the chuck table 110, a Y-axis position detection unit (not shown) for detecting the Y-axis position of the cutting unit 120, a Z-axis position detection unit for detecting the Z-axis position of the cutting unit 120, and an angle detection unit for detecting an angle around the axis of the chuck table 110. The X-axis position detection unit and the Y-axis position detection unit can be configured with a linear scale parallel to the X-axis or Y-axis and a reading head. The Z-axis position detection unit detects the Z-axis position of the cutting unit 120 using motor pulses. The angle detection unit is configured with a well-known rotary encoder or the like.

[0036] The X-axis position detection unit, the Y-axis position detection unit, and the Z-axis position detection unit output the position of the chuck table 110 in the X-axis direction and the position of the cutting unit 120 in the Y-axis direction or Z-axis direction to the control unit 170. The angle detection unit outputs the angle of the chuck table 110 around its axis from a reference position to the control unit 170. In Embodiment 1, the positions of each component of the cutting device 100 in the X-axis, Y-axis, and Z-axis directions are determined based on a predetermined reference position (not shown).

[0037] The cutting device 100 also includes a cassette elevator 150 on which a cassette 151 containing workpieces 200 before and after cutting is placed and which moves the cassette 151 in the Z-axis direction, a cleaning unit 160, and a transport unit (not shown). The cassette 151 is a storage container capable of accommodating multiple workpieces 200 at intervals in the Z-axis direction and is equipped with an loading / unloading port 152 for loading and unloading the workpieces 200. The cassette elevator 150 is positioned next to one side in the Y-axis direction of the chuck table 110 located in the loading / unloading area, and the loading / unloading port 152 is positioned on the side of the chuck table 110 located in the loading / unloading area, on which the cassette 151 is placed.

[0038] The cleaning unit 160 is used to clean the workpiece 200 after cutting. The cleaning unit is positioned next to the chuck table 110 located in the loading / unloading area, on the other side in the Y-axis direction, and is positioned in line with the cassette 151 and the chuck table 110 located in the loading / unloading area in the Y-axis direction. The cleaning unit 160 includes a spinner table 161 for suction holding the workpiece and a cleaning fluid supply nozzle 162 for supplying cleaning fluid to the surface 201 of the workpiece 200 held by the spinner table 161.

[0039] The transport unit transports the workpiece 200 across the cassette 151, the chuck table 110, and the spinner table 161 of the washing unit 160.

[0040] The control unit 170 controls each component of the cutting device 100 to cause the cutting device 100 to perform machining operations on the workpiece 200. The control unit 170 is a computer having a arithmetic processing unit with a microprocessor such as a CPU (central processing unit), a storage device with memory such as ROM (read-only memory) or RAM (random access memory), and an input / output interface device. The arithmetic processing unit of the control unit 170 performs calculations according to the computer program stored in the storage device and outputs control signals for controlling the cutting device 100 to each component of the cutting device 100 via the input / output interface device.

[0041] The control unit 170 is connected to a display unit (not shown) which consists of a liquid crystal display device that displays the status of machining operations and images, an input unit used by the operator to register machining conditions, and a notification unit. The input unit consists of at least one of a touch panel provided on the display unit and an external input device such as a keyboard. The notification unit notifies the operator by emitting at least one of sound and light.

[0042] Furthermore, the control unit 170 includes a machining control unit 171. The machining control unit 171 controls each of the above-mentioned components of the cutting device 100 to cause each component of the cutting device 100 to perform machining operations on the workpiece 200. The function of the machining control unit 171 is realized by the arithmetic processing unit performing calculations according to a computer program stored in the memory device.

[0043] Furthermore, the cutting device 100 includes a cutting blade detection mechanism 1, which is partially shown in Figure 3. The cutting blade detection mechanism 1 detects the state of the cutting edge 124 of the cutting blade 121. In this invention, the cutting blade detection mechanism 1 detects the state of the cutting edge 124 of the cutting blade 121, including whether or not the cutting edge 124 is chipped, the position of the tip of the cutting edge 124 indicating the wear state of the cutting edge 124, and whether or not the cutting edge 124 is chipped all the way around.

[0044] (Cutting blade detection mechanism) As shown in Figure 3, the cutting blade detection mechanism 1 comprises a mechanism body 2, multiple light-emitting means, namely light-emitting bodies 10, and multiple light-receiving means, namely light-receiving bodies 20. The mechanism body 2 is attached to the blade cover 126 and positioned above the cutting blade 121. The mechanism body 2 has a pair of vertical parts 3 spaced apart along the Y-axis and each extending in the Z-axis direction, between which the cutting edge 124 of the cutting blade 121 is positioned, and a connecting part 4 connecting the upper ends of the vertical parts 3. The mechanism body 2 forms a blade entry part 5 between the pair of vertical parts 3, into which the cutting edge 124 of the cutting blade 121 is inserted. That is, the cutting blade detection mechanism 1 is equipped with a blade entry part 5.

[0045] The main body of the mechanism 2 has an adjustment screw 6 that is screwed into a threaded hole in the blade cover 126 and attached to the connecting part 4. When the adjustment screw 6 is rotated around the axis by an operator or the like, the main body of the mechanism 2 moves along the Z-axis direction relative to the blade cover 126, and the radial position of the cutting edge 124 of the cutting blade 121 relative to the blade cover 126 is adjusted.

[0046] Multiple light-emitting elements 10 are arranged on one side of the vertical section 3 (hereinafter referred to as reference numeral 3-1) in the Y-axis direction, which is the rotation axis of the cutting blade 121. As shown in Figures 3 and 4, the multiple light-emitting elements 10 are arranged adjacent to each other in series in the radial direction of the cutting edge 124 of the cutting blade 121. The multiple light-emitting elements 10 face the other side of the vertical section 3 (hereinafter referred to as reference numeral 3-2) and are arranged on a straight line along the Z-axis direction, that is, along the radial direction of the cutting edge 124 of the cutting blade 121. The light-emitting elements 10 are the ends of optical fibers 12 connected to the light-emitting element 11 shown in Figure 5, and they irradiate the light 13 emitted by the light-emitting element 11 toward the other side of the vertical section 3-2. The light-emitting element 11 is, for example, an LED (Light-Emitting Diode) or an LD (Laser Diode).

[0047] Multiple photodetectors 20 are arranged on the vertical section 3-2 on the other side in the Y-axis direction, which is the rotation axis of the cutting blade 121. As shown in Figures 3 and 4, the multiple photodetectors 20 are arranged adjacent to each other in series in the radial direction of the cutting edge 124 of the cutting blade 121 on the other side of the vertical section 3-2. The multiple photodetectors 20 face the vertical section 3-1 on one side and are arranged on a straight line along the Z-axis direction, that is, along the radial direction of the cutting edge 124 of the cutting blade 121, and face the multiple light-emitting elements 10.

[0048] Each photodetector 20 corresponds one-to-one with a light emitter 10 and faces the corresponding light emitter 10 along the Y-axis direction, which is the rotation axis of the cutting blade 121. The photodetectors 20 are at the ends of the optical fiber 22 and each receives the light 13 emitted by the corresponding light emitter 10.

[0049] In Embodiment 1, 16 light-emitting elements 10 and 16 light-receiving elements 20 are arranged in each of the vertical sections 3-1 and 3-2. Also, in Embodiment 1, since the light-emitting elements 10 and 20 are arranged in the vertical sections 3-1 and 3-2, the blade entry section 5 is formed between the multiple light-emitting elements 10 and the multiple light-receiving elements 20.

[0050] Furthermore, as shown in Figure 5, the cutting blade detection mechanism 1 includes a photoelectric converter 30, an amplifier 40, and a control unit 170 which is a control means. Thus, in Embodiment 1, the control unit 170 controls the machining operation of the entire cutting device 100 and also constitutes the cutting blade detection mechanism 1. However, in the present invention, the control means that constitute the cutting blade detection mechanism 1 may be provided separately from the control unit 170 which controls the machining operation of the entire cutting device 100.

[0051] The photoelectric converter 30 converts the light 13 received by each of the multiple photodetectors 20 into a signal 31 with a voltage value corresponding to the amount of light 13. In Embodiment 1, multiple photoelectric converters 30 are provided, with one-to-one correspondence to each photodetector 20. The photoelectric converter 30 is connected to the other end of an optical fiber 22, the end of which is a photodetector 20, and the corresponding photodetectors 20 are connected to the corresponding light-emitting elements 10 via the photodetectors 20. In Embodiment 1, each photoelectric converter 30 is connected to the transmittance calculation unit 174 of the control unit 170 by a circuit 50. That is, in Embodiment 1, the same number of photoelectric converters 30 and circuits 50 are provided as the number of light-emitting elements 10 and photodetectors 20, and the circuits 50 are connected to the photodetectors 20 and light-emitting elements 10 via the photoelectric converters 30.

[0052] The photoelectric converter 30 receives light 13 received by the corresponding photodetector 20 via the optical fiber 22, converts the light 13 received by the corresponding photodetector 20 into a signal 31 with a voltage value corresponding to the amount of light, and outputs the converted signal 31 to the amplifier 40 arranged on the circuit 50. The photoelectric converter 30 is, for example, a PD (photodiode).

[0053] The amplifier 40 adjusts the voltage value of the signal 31 output from the photoelectric converter 30. Multiple amplifiers 40 are provided, corresponding one-to-one with the photodetector 20 and the photoelectric converter 30, and are arranged on the circuit 50. That is, in Embodiment 1, the same number of amplifiers 40 are provided as the number of light emitters 10, photodetectors 20, photoelectric converters 30 and circuits 50. The amplifier 40 adjusts the voltage value of the signal 31 output from the corresponding photoelectric converter 30 and outputs the adjusted signal 41 to the transmittance calculation unit 174 of the control unit 170. Figure 5 shows an example where the voltage values ​​of signals 31 and 41 are 13mV.

[0054] Furthermore, in Embodiment 1, the cutting blade detection mechanism 1 includes a selector 60. The selector 60 is located on a circuit 50 that transmits the signal 31 output from the photoelectric converter 30 and the signal 41 whose voltage value has been adjusted by the amplifier 40. In Embodiment 1, the selector 60 is located between the amplifier 40 on all circuits 50 and the transmittance calculation unit 174, and is connected to all photoelectric converters 30 and all amplifiers 40 via the circuit 50, and is connected to the transmittance calculation unit 174 via all circuits 50.

[0055] The selector 60 receives a signal 41, which is output from the photoelectric converter 30 and whose voltage value is adjusted by the amplifier 40, through all the circuits 50. As shown in Figure 5, the selector 60 can output the signal 41 input via the circuits 50 to the transmittance calculation unit 174 via the circuits 50. The selector 60 can also select one of the multiple circuits 50 to stop the output of the input signal 41 to the transmittance calculation unit 174, and can stop the output of the signal 41 via the selected circuit 50. Furthermore, if the output of the signal 41 via the selected circuit 50 is stopped, the selector 60 can also output the signal 41 input from another circuit 50 via the selected circuit 50, as shown in Figure 6.

[0056] In Embodiment 1, the functions of the photoelectric converter 30, amplifier 40, and selector 60 are realized by dedicated processing circuits (hardware) such as a single circuit, a composite circuit, a programmed processor, or a parallel programmed processor.

[0057] Furthermore, in Embodiment 1, the control unit 170 constituting the cutting blade detection mechanism 1 includes a circuit identification unit 172, a selector control unit 173, and a transmittance calculation unit 174, as shown in Figure 5.

[0058] The circuit identification unit 172 identifies a circuit 50 (hereinafter referred to as reference numeral 50-1, shown in Figures 5 and 6) from among a plurality of circuits 50 that transmits a signal 41 output from the photoelectric converter 30 and whose voltage value has been adjusted by the amplifier 40 for a predetermined period of time while the spindle 123 is rotating the cutting blade 121 located inside the blade entry section 5 while supplying cutting fluid. For example, as shown in Figure 5, if the light 13 emitted by the three light emitters 10 (hereinafter referred to as reference numeral 10-1) furthest from the axis of the cutting blade 121 is received by the photodetector 20 (hereinafter referred to as reference numeral 20-1) without being blocked by the cutting blade 121, and the light 13 emitted by the other light emitters 10 is blocked by the cutting blade 121 and not received by the photodetector 20, the circuit identification unit 172 identifies a circuit 50-1 connected to the three light emitters 10-1 furthest from the axis of the cutting blade 121.

[0059] The selector control unit 173 controls the selector 60 to stop the output of the signal 41 of all circuits 50-1 except for at least one circuit 50-1 on the side closest to the cutting edge 124 of the cutting blade 121, out of the multiple circuits 50-1 identified by the circuit identification unit 172, while the spindle 123 is rotating the cutting blade 121 located at the blade entry point 5, while supplying cutting fluid. In Embodiment 1, the selector control unit 173 identifies the circuit 50-1 (hereinafter referred to as reference numeral 50-2) connected to the photodetector 20-1 and light emitter 10-1 that are closest to the axis of the cutting blade 121, out of the multiple circuits 50-1 identified by the circuit identification unit 172.

[0060] The selector control unit 173 controls the selector 60 to stop the output of the signal 41 to the transmittance calculation unit 174 for all circuits 50-1 identified by the circuit identification unit 172, except for circuit 50-2 identified by the selector control unit 173. In Embodiment 1, the selector control unit 173 also controls the selector 60 to transmit the signal 41 (hereinafter referred to as reference numeral 41-1) input from circuit 50-2, which is connected to the photodetector 20-1 and light emitter 10-1 that are closest to the axis of the cutting blade 121, to the circuit 50-1 from which the selector 60 has stopped outputting the signal 41 to the transmittance calculation unit 174, and to output the signal 41-1 to the transmittance calculation unit 174 via the aforementioned circuit 50-1, as shown in Figure 6.

[0061] The transmittance calculation unit 174 sums the voltage values ​​of signals 41 and 41-1 input from all circuits 50, 50-1, and 50-2, and calculates the transmittance of the light 13 received by the photodetectors 20 and 20-1 based on the summed voltage values, thereby detecting the state of the cutting edge 124 of the cutting blade 121. Transmittance is defined as a value where 100 percent is the case when all photodetectors 20 and 20-1 receive the light 13, and 0 percent is the case when none of the photodetectors 20 receive the light 13. In other words, it is a value that indicates the ratio of the light 13 emitted by light emitters 10 and 10-1 that passes through the blade entry part 5, compared to the case when all the light 13 emitted by multiple light emitters 10 and 10-1 passes through the blade entry part 5. In short, the transmittance is a value that increases as the cutting edge 124 of the cutting blade 121 that has entered the blade entry portion 5 wears down, and increases periodically when a part of the cutting edge 124 of the cutting blade 121 that has entered the blade entry portion 5 is chipped.

[0062] The functions of the circuit identification unit 172, the selector control unit 173, and the transmittance calculation unit 174 are realized by the arithmetic processing unit performing calculations according to a computer program stored in the memory device.

[0063] In the cutting device 100, the machining control unit 171 controls each of the above-mentioned components of the cutting device 100, and during the machining operation in which the workpiece 200 held in the chuck table 110 is cut with the cutting blade 121 while supplying cutting fluid, as shown in Figure 5, multiple light emitters 10 of the cutting blade detection mechanism 1 irradiate light 13 toward multiple light receivers 20, and the transmittance calculation unit 174 detects the state of the cutting edge 124 of the cutting blade 121.

[0064] At this time, the photodetector 20-1 whose light 13 emitted by the corresponding light emitter 10-1 is not blocked by the cutting blade 121 receives the light 13, while the photodetector 20 whose light 13 emitted by the corresponding light emitter 10 is blocked by the cutting blade 121 does not receive the light 13. The photoelectric converter 30 connected to the photodetector 20-1 that receives the light 13 outputs a signal 31, and the amplifier 40, which receives the signal 31 from the photoelectric converter 30, adjusts the voltage value and outputs signals 41 and 41-1 to the transmittance calculation unit 174 via the selector 60. The photoelectric converter 30 connected to the photodetector 20 that does not receive the light 13 does not output a signal 31.

[0065] For example, when the cutting edge 124 of the cutting blade 121 wears down from the position shown by the dashed line in Figure 5 to the position shown by the solid line in Figure 5, the light 13 emitted by the light emitter 10-1 is received by the light receiver 20-1 without being blocked by the cutting blade 121, while the light 13 emitted by the other light emitter 10 is blocked by the cutting blade 121 and not received by the light receiver 20. The signal 31 output by the photoelectric converter 30 connected to the light receiver 20-1 is input to the amplifier 40 via circuit 50-1, and the signals 41 and 41-1 output by the amplifier 40 are input to the transmittance calculation unit 174 via selector 60, while other circuits 50 do not transmit signals 31 and 41.

[0066] Then, the cutting blade detection mechanism 1, specifically the circuit identification unit 172, identifies the circuit 50-1 that transmits signals 41 and 41-1 from among the multiple circuits 50. The cutting blade detection mechanism 1, specifically the selector control unit 173, identifies the circuit 50-2 that is connected to the photodetector 20-1 and light-emitting element 10-1 that are closest to the axis of the cutting blade 121 from among the multiple circuits 50-1 identified by the circuit identification unit 172.

[0067] In the cutting blade detection mechanism 1, the selector control unit 173 instructs the selector 60 to stop the output of signals 41 to the transmittance calculation unit 174 for circuits 50-1 other than circuit 50-2 identified by the selector control unit 173, out of the multiple circuits 50-1 identified by the circuit identification unit 172. As shown in Figure 6, the cutting blade detection mechanism 1 causes the selector control unit 173 to output signals 41-1 input from circuit 50-2 identified by the selector control unit 173 to the transmittance calculation unit 174 via the circuit 50-1 from which the selector 60 has stopped the output of signals 41 to the transmittance calculation unit 174.

[0068] The cutting blade detection mechanism 1 uses a transmittance calculation unit 174 to detect the state of the cutting edge 124 of the cutting blade 121 based on the voltage value of the signal 41-1 input from the selector 60. For example, if the cutting blade detection mechanism 1 detects that part or all of the cutting edge 124 of the cutting blade 121 has been chipped, the machining control unit 171 of the control unit 170 stops the machining operation and activates the notification unit to notify the operator.

[0069] As described above, in the cutting blade detection mechanism 1 according to Embodiment 1, the circuit identification unit 172 identifies a circuit 50-1 that transmits a signal 41 from the photoelectric converter 30 for a predetermined period of time from among a plurality of circuits 50, and the selector control unit 173 identifies a circuit 50-2 connected to the photodetector 20-1 and light emitter 10-1 that are closest to the axis of the cutting blade 121 from among the plurality of circuits 50-1 identified by the circuit identification unit 172, and causes the selector 60 to stop the output of the signal 41 from circuits 50-1 other than circuit 50-2. Furthermore, in the cutting blade detection mechanism 1 according to Embodiment 1, the selector control unit 173 causes the selector 60 to output the signal 41-1 input from circuit 50-2 to the transmittance calculation unit 174 via circuit 50-1 from which the selector 60 has stopped the output of the signal 41 to the transmittance calculation unit 174, and the transmittance calculation unit 174 detects the state of the cutting edge 124 of the cutting blade 121 based on the voltage value of the signal 41-1 input from the selector 60.

[0070] Thus, the cutting blade detection mechanism 1 according to Embodiment 1 identifies the circuit 50-2 connected to the photodetector 20-1 and light-emitting body 10-1 that are closest to the axis of the cutting blade 121 from among the multiple circuits 50-1 identified by the circuit identification unit 172, and has the selector 60 stop the output of the signals 41 of the circuits 50-1 other than circuit 50-2. As a result, noise caused by the influence of cutting water included in the signal 41-1 input to the transmittance calculation unit 174 can be reduced, and the influence of variations due to the amount of light received by each of the multiple photodetectors 20, 20-1 can be reduced.

[0071] As a result, the cutting blade detection mechanism 1 according to Embodiment 1 has the effect of reducing the influence of cutting fluid and improving the accuracy of detecting the cutting blade 121 during cutting, that is, it has the effect of suppressing a decrease in the detection accuracy of the state of the cutting edge 124 of the cutting blade 121.

[0072] Furthermore, in the cutting blade detection mechanism 1 according to Embodiment 1, the selector control unit 173 causes the selector 60 to output the signal 41-1, which is input from at least one circuit 50-2 on the side closest to the cutting edge 124 of the cutting blade 121 identified by the selector control unit 173, to the transmittance calculation unit 174 via a circuit 50-1 in which the selector 60 stops outputting the signal 41 to the transmittance calculation unit 174. This reduces noise caused by the influence of cutting fluid included in the signal 41-1 input to the transmittance calculation unit 174.

[0073] [Embodiment 2] The cutting blade detection mechanism of the cutting device according to Embodiment 2 will be described based on the drawings. Figure 7 is a block diagram showing the state in which the selector control unit of the circuit identification unit of the cutting blade detection mechanism according to Embodiment 2 has stopped the output of all circuits except the one closest to the tip of the cutting blade. Note that in Figure 7, the same reference numerals are used for the same parts as in Embodiment 1, and their description is omitted.

[0074] The cutting blade detection mechanism 1 according to Embodiment 2 is the same as Embodiment 1, except that the control unit 170 further comprises a light emission stop unit 175, as shown in Figure 7. The light emission stop unit 175 stops the emission of light from the light emitter 10-1 (hereinafter referred to as reference numeral 10-2) connected to at least one circuit 50-1 other than the circuit 50-1 closest to the cutting edge 124 of the cutting blade 121, among the circuits 50-1 identified by the circuit identification unit 172.

[0075] In the cutting blade detection mechanism 1 according to Embodiment 2, the circuit identification unit 172 identifies circuit 50-1 that transmits signal 41 from among the multiple circuits 50, and the selector control unit 173 identifies circuit 50-2 connected to the photodetector 20-1 and light emitter 10-1 that are closest to the axis of the cutting blade 121 from among the multiple circuits 50-1 identified by the circuit identification unit 172, and causes the selector 60 to stop the output of signal 41 from circuits 50-1 other than circuit 50-2. In the cutting blade detection mechanism 1 according to Embodiment 2, the selector control unit 173 causes the selector 60 to output the signal 41-1 input from circuit 50-2 to the transmittance calculation unit 174 via circuit 50-1, which the selector 60 has stopped outputting the signal 41-1 to the transmittance calculation unit 174. Then, as shown in Figure 7, the light emission stop unit 175 stops the irradiation of light 13 from the light emitter 10-2 connected to the circuit 50-1 other than the circuit 50-2 identified by the selector control unit 173, among the circuits 50-1 identified by the circuit identification unit 172. The function of the light emission stop unit 175 is realized by the arithmetic processing unit performing calculation processing according to a computer program stored in the memory device.

[0076] The cutting blade detection mechanism 1 according to Embodiment 2 identifies the circuit 50-2 connected to the light receiver 20-1 and light emitter 10-1 closest to the axis of the cutting blade 121 from among the multiple circuits 50-1 identified by the circuit identification unit 172, and has the selector 60 stop the output of the signals 41 of the circuits 50-1 other than circuit 50-2. Therefore, similar to Embodiment 1, it has the effect of suppressing a decrease in the detection accuracy of the state of the cutting edge 124 of the cutting blade 121.

[0077] Furthermore, the cutting blade detection mechanism 1 according to Embodiment 2 has the effect of suppressing power consumption because the light emission stop unit 175 stops the irradiation of light 13 from the light emitter 10-1 connected to circuits 50-1 other than circuit 50-2 identified by the selector control unit 173 among the circuits 50-1 identified by the circuit identification unit 172.

[0078] It should be noted that the present invention is not limited to the embodiments described above. That is, it can be implemented with various modifications without departing from the core of the present invention. In the present invention, for example, the selector control unit 173 may identify a plurality of circuits 50-2 connected to the photodetector 20-1 and light emitter 10-1 closest to the axis of the cutting blade 121 from among the plurality of circuits 50-1 identified by the circuit identification unit 172, and may cause the selector 60 to stop the output of the signal 41 of the circuits 50-1 outside of circuit 50-2. In this case, the light emission stop unit 175 may stop the light emission from the light emitter 10-2 connected to the circuits 50-1 other than the plurality of circuits 50-2 closer to the cutting edge 124 of the cutting blade 121 from among the circuits 50-1 identified by the circuit identification unit 172. [Explanation of symbols]

[0079] 1. Cutting blade detection mechanism 5. Blade entry point 10,10-1 Luminescent body 13 light 20,20-1 Photodetector 30 Photoelectric Converters 31,41 signal 50 circuits 50-1 Circuit 50-2 Circuit 60 Selector 100 Cutting equipment 110 Chuck Table 121 Cutting Blades 124 cutting edge 170 Control unit (control means) 172 Circuit identification part 173 Selector Control Unit 175 Light emission stop section 200 Workpiece

Claims

1. A cutting blade detection mechanism for a cutting device comprising: a plurality of light-emitting elements arranged adjacent to each other in series in the radial direction of a cutting blade having an annular cutting edge for cutting a workpiece held on a chuck table that holds a workpiece; a plurality of photodetectors disposed on the other side of the cutting blade in the rotational direction of the cutting blade, facing the plurality of light-emitting elements, and receiving light irradiated by the light-emitting elements; a photoelectric converter that converts the light received by the plurality of photodetectors into a signal of a voltage value corresponding to the amount of light; and a control means, The circuit that transmits the signal output from the photoelectric converter to the control means is arranged on a circuit and has a selector that selects a circuit to stop the output of the input signal, The photoelectric converters and circuits are provided in the same number as the light emitters and light receivers, and each circuit corresponds to each photoelectric converter. The control means is, A circuit identification unit identifies the circuit that transmits the signal from the photoelectric converter for a predetermined period of time from among the circuits, When the circuit identification unit identifies multiple circuits that transmit the signal from the photoelectric converter, the selector control unit controls the selector to stop the output of the signal from all circuits except at least one circuit among the multiple circuits identified by the circuit identification unit that is closer to the cutting edge of the cutting blade. A cutting blade detection mechanism that includes the above, reduces the influence of variations due to the amount of light received by each of the multiple photodetectors, and enables high-precision detection of the cutting blade.

2. The control means is, The cutting blade detection mechanism according to claim 1, further comprising a light emission stopping unit that stops the emission of light from the light emitter connected to at least one circuit other than the circuit closest to the cutting edge of the cutting blade among the circuits identified by the circuit identification unit.

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