Optical measurement device

Abstract

To provide an optical measurement device that can prevent laser beams from directly entering a light receiving device during measurement.SOLUTION: An optical measurement device 1 includes: a light source device 35 that emits wavelength-swept light; a conveyance device 10 that conveys a measurement object M; an irradiation device 40 which guides the wavelength-swept light from the light source device 35 to a measurement position P on a conveyance path of the conveyance device 10 and includes an optical path switching unit 42 that switches the optical path; a measurement light receiving device 51 that receives the wavelength-swept light applied to the measurement position P; an object detection sensor 55 that detects the conveyed measurement object M; a conveyance detection sensor that detects the conveyance speed or displacement in the conveyance direction of the measurement object M; and a control device 65. The control device 65 estimates the timing at which the measurement object M reaches the measurement position P on the basis of the detection by the object detection sensor 55 and the conveyance speed or displacement in the conveyance direction detected by the conveyance detection sensor, and controls the optical path switching unit 42 at this timing so as to be the optical path that allows the wavelength-swept light to be received by the light receiving device while the measurement object M exists at the measurement position P.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an optical measurement device. [Background technology]

[0002] As one of the measurement techniques that utilize optical characteristics, spectroscopy using a wavelength-swept spectrometer has been known. This spectrometer generates wavelength-swept light whose wavelength changes over time, and irradiates the object to be measured with the generated wavelength-swept light. The wavelength-swept light is a pulse or pulse train in which the time and wavelength have a one-to-one relationship. The time waveform of the light obtained by irradiating the object to be inspected with this wavelength-swept light is detected by a photoreceiver, and the signal waveform output from the photoreceiver represents a spectrum in which the time axis corresponds to the wavelength.

[0003] Spectroscopic analysis is classified into a transmission type, in which the light transmitted through the object is used as the object light, and a reflection type, in which the reflected light is used as the object light. The reflection type is suitable for measuring objects with high reflectance, but the optical information obtained is limited to that near the surface of the object. Therefore, it cannot be said that it has sufficient accuracy for measuring objects such as precision industrial products, specimens taken from animals and plants, objects ingested by humans, and liquids and gases produced in production plants.

[0004] On the other hand, the transmission type can obtain optical characteristics including not only the surface but also the deeper parts of the object, and is therefore suitable for measuring foods and beverages (hereinafter collectively referred to as food and beverages). Patent Document 1 below discloses a transmission type product inspection device. This product inspection device comprises an irradiation optical system that irradiates the surface of the product (inspection target) with pulsed light, and a light receiver (photodetector) that is provided on the back side of the product and receives the light that has passed through the product.

[0005] 10 shows an example of a wavelength sweep type spectroscopic device 100. The spectroscopic device 100 includes a light source device 110, a spectroscopic head 120, and a processor .

[0006] The light source device 110 generates wavelength swept light L1, and the generated wavelength swept light L1 is guided to the spectroscopic head 120. The irradiation optical system 121 of the spectroscopic head 120 irradiates the wavelength swept light L1 onto a sample T, and transmitted light (object light) L2 transmitted through the sample T is received (detected) by a first photoreceiver 122. In addition, in the irradiation optical system 121, a part of the wavelength swept light L1 is branched off as reference light L3, and the branched reference light L3 is received (detected) by a second photoreceiver 123.

[0007] The first detection signal S1 output from the first photoreceiver 122 and the second detection signal S2 output from the second photoreceiver 123 are each transmitted to the arithmetic processing device 130. The object light L2 and the reference light L3 each inherit the one-to-one time-wavelength correspondence of the wavelength swept light L1. Therefore, the time waveform of the first detection signal S1 can be converted into the spectrum of the object light L2 by converting the time axis into wavelength. Similarly, the time waveform of the second detection signal S2 can be converted into the spectrum of the reference light L3 by converting the time axis into wavelength. The arithmetic processing device 130 measures (calculates) the spectral characteristics (reflectance) of the sample T by calculating the ratio of each corresponding wavelength of the object light L2 to the reference light L3. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2020-159973 A Summary of the Invention [Problem to be solved by the invention]

[0009] In the above-mentioned conventional transmission type spectroscopic device, when the product to be measured (hereinafter also referred to as the product) has low light transmittance and high diffusion properties, the light receiver is designed and selected assuming low power incident light, while the light source device uses a pulse laser with high peak power to increase the power of the transmitted light.

[0010] Furthermore, when inspecting industrially mass-produced products, the products are generally transported at high speed by a transport device. Therefore, if the stability of the product during transportation deteriorates, the product may fall off the transport device or may shift out of position, resulting in a situation where the product is not present at the measurement position where it should be. If such a situation occurs, the wavelength swept light L1, which is a pulsed laser beam irradiated at the measurement position, will be directly incident on the photodetector without passing through the product.

[0011] In addition, depending on the manner in which the products are transported, there may be gaps between continuously transported products, and in such cases, there is also a risk that the laser beam will be directly incident on the receiver through the gaps.

[0012] Thus, as described above, when a photoreceiver is designed and selected assuming low-power incident light, if a high-peak power laser beam is directly incident on the photoreceiver, and the power of the laser beam exceeds the allowable power of the photoreceiver, the power of the incident laser beam may damage (reduce) the reliability of the photoreceiver.

[0013] In particular, elements that have an amplification mechanism within them, such as avalanche photodiodes, are known to have a low damage threshold. For example, the damage threshold of the InGaAs avalanche photodetector APD430C from THORLABS, USA, is 1 mW. Since the power of the laser beam used in this spectroscopic method is much greater than this, if the laser beam is incident directly on the element, it will be damaged.

[0014] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical measurement device capable of preventing a laser beam from being directly incident on a photoreceiver during measurement. [Means for solving the problem]

[0015] To solve the above problems, the present invention provides: a light source device that generates wavelength swept light; a conveying device including two endless annular conveying belts arranged opposite each other to form a linear conveying path, and a driving unit for rotating the conveying belts, and conveying a measurement object along the conveying path while the measurement object is straddled between the two conveying belts; an irradiation device having an optical path for guiding and irradiating the wavelength swept light generated by the light source device to a measurement position set on the transport path, the irradiation device having an optical path switching unit provided on the optical path for switching the optical path of the wavelength swept light; a light receiving device that receives the wavelength swept light irradiated onto the measurement position by the irradiating device; an object detection sensor provided upstream of the measurement position in a conveying direction of the conveying device, the object detection sensor detecting a measurement object conveyed by the conveying device; a conveyance detection sensor for detecting a conveyance speed or a conveyance direction displacement of the conveyor belt; A control device that controls a drive unit of the transport device and an optical path switching unit of the irradiation device, The control device estimates the timing when the object to be measured will reach the measurement position based on detection by the object detection sensor and the displacement in the conveying direction or the conveying speed detected by the conveying detection sensor, and controls the optical path switching unit in synchronization with the estimated timing to set an optical path in which the wavelength swept light is received by the light receiving device while the object to be measured is present at the measurement position, and sets an optical path in which the wavelength swept light is not received by the light receiving device only while the object to be measured is not present at the measurement position.

[0016] According to the optical measurement device of this aspect (first aspect), the measurement object is conveyed along the conveying path while straddling two conveying belts of the conveying device. Meanwhile, the light source device generates wavelength swept light, and the generated wavelength swept light is guided by the irradiation device to a measurement position set on the conveying path, and the wavelength swept light irradiated to the measurement position is received by the light receiving device.

[0017] The measurement object conveyed by the conveying device is detected by an object detection sensor provided upstream of the measurement position, and the control device estimates the timing at which the measurement object reaches the measurement position based on the detection of the measurement object by the object detection sensor and the displacement of the conveying speed or conveying direction of the conveying belt detected by the conveying detection sensor, and controls the optical path switching unit of the irradiation device in synchronization with the estimated timing, so that the optical path is switched so that the wavelength swept light is received by the light receiving device while the measurement object is present at the measurement position, and the wavelength swept light is not received by the light receiving device while the measurement object is not present at the measurement position. Then, while the measurement object is present at the measurement position, the wavelength swept light passes through the measurement object and is received by the light receiving device, and a detection signal according to the optical characteristics of the measurement object is output by the light receiving device.

[0018] Thus, according to this optical measurement device, while the object to be measured is not present at the measurement position, the optical path switching unit switches the optical path of the wavelength swept light to an optical path that is not received by the light receiving device, thereby preventing the wavelength swept light from being received directly by the light receiving device and avoiding damage to the light receiving device that would occur if the wavelength swept light were received directly by the light receiving device.

[0019] In the first aspect, the optical path switching section may include any one of a galvanometer mirror, a MEMS (Micro Electro Mechanical Systems) mirror, a piezoelectric driven mirror, and a polygon mirror.

[0020] In the first aspect, the irradiation device may further include an aperture on the exit side of the optical path switching section.

[0021] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: a light source device that generates wavelength swept light; a conveying device including two endless annular conveying belts arranged opposite each other to form a linear conveying path, and a driving unit for rotating the conveying belts, and conveying a measurement object along the conveying path while the measurement object is straddled between the two conveying belts; an irradiation device having an optical path for guiding and irradiating the wavelength swept light generated by the light source device to a measurement position set on the transport path, and having a light blocking portion provided on the optical path for switching between transmitting and blocking the wavelength swept light; a light receiving device that receives the wavelength swept light irradiated onto the measurement position by the irradiating device; an object detection sensor provided upstream of the measurement position in a conveying direction of the conveying device, the object detection sensor detecting a measurement object conveyed by the conveying device; a conveyance detection sensor for detecting a conveyance speed or a conveyance direction displacement of the conveyor belt; A control device that controls a drive unit of the transport device and a light blocking unit of the irradiation device, The control device relates to an optical measurement device configured to estimate the timing when the object to be measured will reach the measurement position based on detection by the object detection sensor and the displacement in the conveying speed or conveying direction detected by the conveying detection sensor, and to control the shading part in synchronization with the estimated timing to make the shading part transparent while the object to be measured is present at the measurement position, and to make the shading part opaque while the object to be measured is not present at the measurement position.

[0022] According to the optical measurement device of this aspect (second aspect), the measurement object is conveyed along the conveying path while straddling two conveying belts of the conveying device. Meanwhile, the light source device generates wavelength swept light, and the generated wavelength swept light is guided by the irradiation device to a measurement position set on the conveying path, and the wavelength swept light irradiated to the measurement position is received by the light receiving device.

[0023] The measurement object conveyed by the conveying device is detected by an object detection sensor provided upstream of the measurement position, and the control device estimates the timing when the measurement object reaches the measurement position based on the detection of the measurement object by the object detection sensor and the displacement of the conveying speed or conveying direction of the conveying belt detected by the conveying detection sensor, and controls the light-shielding part of the irradiation device in synchronization with the estimated timing, so that the wavelength swept light is transmitted while the measurement object is present at the measurement position, and the wavelength swept light is blocked while the measurement object is not present at the measurement position. Then, only while the measurement object is present at the measurement position, the wavelength swept light is transmitted through the measurement object and received by the light-receiving device, and a detection signal according to the optical characteristics of the measurement object is output by the light-receiving device. The non-transmitting state includes not only the case where the transmission of light is completely blocked, but also the mode where the transmitted light is dimmed.

[0024] Thus, according to this optical measurement device, while the object to be measured is not present at the measurement position, the optical path of the wavelength swept light is blocked by the light shielding portion, thereby preventing the wavelength swept light from being received directly by the light receiving device, and thus avoiding damage to the light receiving device that would occur if the wavelength swept light were received directly by the light receiving device.

[0025] In the second aspect, the light-shielding portion may include either a movable shutter or a variable attenuator, and the variable attenuator may include either a liquid crystal shutter, an acousto-optical modulator, or an electro-optical modulator.

[0026] In each of the above aspects, the wavelength swept light may be configured to pass between the two conveyor belts and be irradiated onto the measurement object. Effect of the Invention

[0027] According to the optical measurement device of the present invention, while the object to be measured is not present at the measurement position, the optical path can be controlled so that the wavelength swept light is not received by the light receiving device, thereby preventing the wavelength swept light from being received directly by the light receiving device and avoiding damage to the light receiving device that would occur if the wavelength swept light were received directly by the light receiving device. [Brief description of the drawings]

[0028] [Figure 1] 1 is a front view showing a schematic configuration of a light measurement device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a plan view showing a conveying device and the like according to the present embodiment. [Diagram 3] 3 is a cross-sectional view taken along the line AA in FIG. 2. [Figure 4] 4 is a cross-sectional view taken along the line CC in FIG. 3. [Diagram 5] 3 is a cross-sectional view taken along the line BB in FIG. 2. [Figure 6] FIG. 2 is an explanatory diagram showing a schematic configuration of the light measurement device according to the present embodiment, and is an explanatory diagram for explaining the light paths in the light source device and the irradiation device. [Figure 7] FIG. 2 is an explanatory diagram for explaining wavelength swept light. [Figure 8] FIG. 2 is an explanatory diagram for explaining spectroscopic analysis by the light measurement device of the present embodiment. [Figure 9] FIG. 13 is an explanatory diagram showing a schematic configuration of a light measurement device according to another embodiment of the present invention. [Figure 10] FIG. 1 is a block diagram showing a conventional light measurement device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

[0030] As shown in Fig. 1 to Fig. 6, the light measurement device 1 of this example is composed of a supply unit 2, a conveying device 10, a light source device 35, an irradiation device 40, a reference light receiving device 50, a measurement light receiving device 51, an object detection sensor 55, a sorting device 60, a control device 65, and a calculation device 70. Details of each part will be described below. Note that the measurement object M in this example is a tablet having a circular planar shape and an elliptical vertical cross-sectional shape, but examples of the measurement object M include medicines (tablets, capsules, etc.) having other shapes, or foods, machine parts, electronic parts, etc. However, the measurement object M is not limited to these.

[0031] The supply unit 2 is a mechanism that aligns the measurement objects M in a line and supplies them to the conveying device 10, and is composed of a hopper 3, a vibrating feeder 4, a chute 5, an alignment table 6, etc. The hopper 3 stores a large number of measurement objects M input from an upper opening, and discharges an appropriate amount of the measurement objects M from its lower opening. The vibrating feeder 4 is provided below the hopper 3, receives the measurement objects M discharged from the lower opening of the hopper 3, and applies vibration to the measurement objects M, thereby moving the measurement objects M along a set path.

[0032] The chute 5 is provided so as to be connected to the conveying end of the vibrating feeder 4, and receives the measurement objects M discharged from the conveying end, slides them diagonally downward, and discharges them from its lower end. The alignment table 6 has a disk-shaped rotating table provided horizontally below the lower end of the chute 5, receives the measurement objects M supplied from the chute 5 on the rotating table, and aligns the measurement objects M in a row by the rotating action of the rotating table before supplying them to the conveying device 10.

[0033] As shown in Figures 2 and 3, the conveying device 10 is composed of a suction box 11 having a long and narrow housing shape, two endless circular conveying belts 15 and 16 arranged side by side facing each other with a predetermined gap between them, an exhaust pump 17 for creating negative pressure inside the suction box 11, and a cover body 24 arranged to surround the suction box 11.

[0034] As shown in FIG. 4, the suction box 11 has a slit 12 that opens on its upper surface and is formed along its longitudinal direction, and further has guide grooves 13 and 14 formed on both sides of the slit 12.

[0035] As shown in Fig. 3, the cover body 24 has a driving pulley 18 and driven pulleys 19, 20, and 21 arranged at four corners so as to surround the suction box 11, and the conveyor belts 15 and 16 are wound around the driving pulley 18 and driven pulleys 19, 20, and 21 while being fitted into guide grooves 13 and 14 formed on the upper surface of the suction box 11, respectively. A driving motor 22 is connected to the driving pulley 18, and the driving pulley 18 is driven by the driving motor 22. When the driving pulley 18 rotates in the direction of arrow D, the conveyor belts 15 and 16 rotate in the direction of arrow E. A rotary encoder 23 is attached to the driving motor 22, and the rotary encoder 23 detects the rotation speed of the driving motor 22, and the running speed (conveying speed) of the conveyor belts 15 and 16 can be calculated from the rotation speed of the driving motor 22.

[0036] This rotary encoder 23 detects the rotation angle per unit time of the drive motor 22, and in this sense, can detect the running speed (conveyance speed) of the conveyor belts 15, 16, but the running speed is equivalent to the movement amount (displacement amount) of the conveyor belts 15, 16, and therefore, this rotary encoder 23 can be considered as a means for detecting the movement amount (displacement amount) of the conveyor belts 15, 16. Also, this rotary encoder 23 functions as a conveyance detection sensor that detects the conveyance speed or displacement in the conveyance direction of the conveyor belt, but such a conveyance detection sensor is not limited to the rotary encoder 23.

[0037] In this embodiment, the conveyor belts 15 and 16 are formed from timing belts, and the drive pulley 18 and the driven pulleys 19, 20 and 21 are each formed from a timing pulley, but the present invention is not limited to such a configuration.

[0038] In this conveying device 10, when the inside of the suction box 11 is evacuated by the exhaust pump 17 to create a negative pressure in the suction box 11, this negative pressure acts between the conveying belts 15, 16 through the slit 12. Then, when the measurement object M is sequentially supplied from the upstream side of this conveying device 10 so as to straddle the conveying belts 15, 16, the supplied measurement object M is adsorbed onto the conveying belts 15, 16 by the action of the negative pressure, and the tablet adsorbed to the conveying belts 15, 16 is conveyed toward the conveying end by the conveying belts 15, 16 traveling in the direction of the arrow E. Thus, in this conveying device 10, the upper surface of the conveying belts 15, 16 is a conveying support surface, and the traveling path is an adsorption conveying path.

[0039] A housing-shaped cover body 30 is provided on one side of the conveying device 10 (in this example, the front side), and the light source device 35, the main parts of the irradiation device 40, and the reference light receiving device 50 are provided within this cover body 30.

[0040] A measurement position P is set at an appropriate position on the suction conveying path formed by the conveyor belts 15 and 16, and a measurement light receiving device 51 is provided above this measurement position P. An object detection sensor 55 is provided above an appropriate position set on the upstream side of the measurement position P on the suction conveying path, and a sorting device 60 is provided above the downstream side of the measurement position P near the end of conveying.

[0041] The light source device 35 includes a pulse light source that emits pulse light, and a stretcher that stretches and emits the pulse light emitted from the pulse light source. Specifically, the pulse light source emits broadband pulse light having a broadband continuous spectrum. The spectrum of the broadband pulse light is continuous over a wavelength range of at least 10 nm, preferably 50 nm, and more preferably 100 nm, for example, in the range of 900 nm to 1300 nm, and the width of the wavelength range of the broadband pulse light only needs to cover the wavelength range required for spectroscopy. In addition, the stretcher generates and emits wavelength swept light by stretching the broadband pulse light emitted from the pulse light source on the time axis.

[0042] FIG. 7 is a diagram showing wavelength swept light, and the upper part shows the intensity (time waveform) IWS(t) of the wavelength swept light, and the lower part shows the change in wavelength λ of the wavelength swept light over time. In this example, the wavelength swept light is a single pulse light, the dominant wavelength at its leading edge is λ1, and the dominant wavelength at its trailing edge is λn, and the wavelength changes over time between λ1 and λn within one pulse. In this example, the wavelength swept light is a positive chirp pulse (λ1>λn) whose frequency increases over time, in other words, whose wavelength shortens over time, but is not limited to this, and the wavelength swept light may be a negative chirp pulse whose wavelength lengthens over time (λ1<λn). Alternatively, the wavelength swept light may be a pulse train consisting of pulses (wave packets) isolated in time for each wavelength.

[0043] The irradiation device 40 is a mechanism that guides the wavelength swept light emitted from the light source device 35 and irradiates it onto a measurement position P set on the transport path of the transport device 10. In this example, the irradiation device 40 is composed of a beam splitter 41, a galvanometer mirror 42, a motor 43, a slit member 44 and a first mirror 45 provided in the cover body 30, as well as a second mirror 46 provided in the suction box 11 of the transport device 10, but may also include other mirrors, lenses, etc.

[0044] The beam splitter 41 is an optical member that is provided on the optical path of the wavelength swept light emitted from the light source device 35 and splits the wavelength swept light into two beams, one of which is transmitted in the emission direction as it is to become a measurement light, and the other beam is reflected at, for example, 45° to become a reference light. The reference light is incident on a reference light receiving device 50 provided on the side of the light source device 35.

[0045] The galvanometer mirror 42 is provided on the optical path of the measurement light transmitted through the beam splitter 41, and reflects the measurement light toward a first mirror 45 disposed above it. The galvanometer mirror 42 is configured to rotate around an axis horizontally perpendicular to the optical axis of the measurement light by a motor 43, and the reflection angle of the measurement light is adjusted by this rotation. The galvanometer mirror 42 and the motor 43 constitute an optical path switching unit. Note that, although the galvanometer mirror 42 is used as the optical path switching unit in this example, the present invention is not limited to this, and instead of the galvanometer mirror 42, a MEMS (Micro Electro Mechanical Systems) mirror, a polygon mirror, a piezo-driven mirror, or the like can be used.

[0046] The slit member 44 is a light-shielding member having a slit as an opening, and is provided between the galvanometer mirror 42 and the first mirror 45. When the measurement light reflected by the galvanometer mirror 42 takes an optical path passing through the slit (illumination optical path), the measurement light reaches the first mirror 45, and when the measurement light takes an optical path not passing through the slit (evacuation optical path), the measurement light is shielded by the slit member 44. Although the slit member 44 functions as an aperture, a member having a structure such as an iris, a pinhole, or a knife edge (a slit with one edge) having a similar function can be used instead.

[0047] The first mirror 45 is disposed so as to reflect the measurement light reflected by the galvanometer mirror 42 toward the second mirror 46 provided in the suction box 11 of the transport device 10. Through holes 24a and 11a are formed in the cover body 24 of the transport device 10 and the side plate of the suction box 11, through which the optical path of the measurement light toward the second mirror 46 passes. The through hole 11a provided in the suction box 11 is a two-stage hole with a large diameter portion 11b on the outside and a small diameter portion 11c on the inside, and the through hole 11a is airtightly sealed by fitting a glass plate 25 into the large diameter portion 11b. Thus, the measurement light reflected by the first mirror 45 reaches the second mirror 46 in the suction box 11 through the through hole 24a and the glass plate 25 provided in the through hole 11a.

[0048] As described above, the second mirror 46 is provided in the suction box 11 of the conveying device 10, and reflects the measurement light reflected by the first mirror 45 upward, passing through the slit 12 provided in the suction box 11 of the conveying device 10 and between the conveying belts 15, 16, and through the measurement position P set on the conveying path.

[0049] In the irradiation device 40 of this example, a collimator for collimating the wavelength swept light emitted from the light source device 35 may be further provided between the light source device 35 and the beam splitter 41 .

[0050] The reference light receiving device 50 detects the reference light dispersed by the beam splitter 41, and outputs an A / D converted digital signal as a reference signal.

[0051] The measurement light receiving device 51 is disposed above the measurement position P, detects the measurement light (object light) that passes through the measurement object M located at the measurement position P, and outputs an A / D converted digital signal as a measurement signal.

[0052] As described above, the object detection sensor 55 is provided at an appropriate position set upstream of the measurement position P, detects the measurement target M transported by the transport device 10, and outputs a detection signal to the control device 65. Note that, although an optical type can be exemplified as the object detection sensor 55, the object detection sensor is not limited to this, and any conventionally known object detection sensor can be used within an applicable range.

[0053] As described above, the sorting device 60 is provided at the end of the conveying path of the conveying device 10, and includes a sorting and recovery mechanism (not shown), a non-defective product recovery chamber, and a defective product recovery chamber, and drives the sorting and recovery mechanism in accordance with commands from the control device 65 to recover non-defective products and defective products in the defective product recovery chamber among the measurement objects M conveyed to the end of the conveying path of the conveying device 10. Note that the sorting and recovery mechanism can be exemplified by a mechanism configured to suck and recover the measurement objects M by negative pressure.

[0054] The control device 65 controls the operations of the vibration feeder 4, the alignment table 6, the exhaust pump 17 and the drive motor 22 of the transport device 10, the light source device 35, the motor 43 of the irradiation device 40, the sorting and recovery mechanism of the sorting device 60, etc. In particular, when the object detection sensor 55 detects the measurement target M, the control device 65 drives the motor 43 of the irradiation device 40 to switch the optical path of the measurement light reflected by the galvanometer mirror 42.

[0055] Specifically, when the control device 65 detects the object to be measured M by the object detection sensor 55 and receives a detection signal from the object detection sensor 55, it calculates the conveying speed of the object to be measured M being conveyed by the conveying belts 15, 16 based on the rotational speed of the drive motor 22 detected by the rotary encoder 23 at that time.

[0056] Next, based on the calculated conveying speed and the distance between the detection position of the object detection sensor 55 and the measurement position P, which has been obtained in advance, the control device 65 calculates the time (timing) from the time of detection of the measurement object M detected by the object detection sensor 55 to the measurement position P, and when the calculated time has elapsed, until the measurement object M passes the measurement position P, it drives the motor 43 to switch the optical path of the measurement light reflected by the galvanometer mirror 42 to an optical path (irradiation optical path) that passes through the slit hole of the slit member 44 (optical path shown by solid lines in Figures 5 and 6), and then, shortly before the measurement object M passes the measurement position P, it drives the motor 43 again to switch the optical path of the measurement light reflected by the galvanometer mirror 42 to an optical path (evacuation optical path) that does not pass through the slit hole of the slit member 44 (optical path shown by dashed double-dashed lines in Figures 5 and 6). As a result of the above, the measurement light is irradiated to the measurement position P only when the measurement object M is at the measurement position P; in other words, when the measurement object M is not at the measurement position P, the measurement light is not irradiated to the measurement position P.

[0057] The time during which the transported measurement object M is present at the measurement position P can be calculated based on the size of the measurement object M in the transport direction (diameter in this example) and the transport speed of the measurement object M.

[0058] The calculation device 70 receives an output signal from the measurement light receiving device 51 which detects the object light, and an output signal from the reference light receiving device 50 which detects the reference light, and processes these signals to detect (measure) the optical characteristics of the object to be measured M.

[0059] In wavelength-swept spectroscopy, there is a one-to-one correspondence between time and wavelength in the wavelength-swept light, and this correspondence is of course also possessed by the reference light and is also inherited by the object light. Using this correspondence between time and wavelength, the calculation device 70 detects (measures) the optical characteristics of the measurement object M.

[0060] The output signal of the measurement light receiving device 51 is D1, the time waveform of the object light indicated by this output signal D1 is IOBJ(t), the output signal of the reference light receiving device 50 is D2, and the time waveform of the reference light indicated by this output signal D2 is IREF(t).The calculation device 70, for example, converts the time waveform of the object light IOBJ(t) into a frequency domain spectrum IOBJ(λ), and similarly converts the time waveform IREF(t) of the reference light into a spectrum and appropriately scales it to calculate the reference spectrum IREF(λ).

[0061] The processing in the calculation device 70 is not particularly limited. As an example, the calculation device 70 calculates the transmittance T(λ) as an optical characteristic of the measurement object M based on the reference spectrum IREF(λ) and the spectrum IOBJ(λ) of the object light using the following formula, and judges whether it is good or bad. T(λ)=IOBJ(λ) / IREF(λ)

[0062] 8 is an explanatory diagram for explaining the spectroscopic analysis by the light measurement device 1 of this embodiment. As described above, since the wavelength swept light has a one-to-one correspondence between time t and wavelength λ, the time waveform IREF(t) can be converted into a frequency domain spectrum IREF(λ).

[0063] The time waveform IOBJ(t) of the object beam also has a one-to-one correspondence between time t and wavelength λ, so the waveform IOBJ(t) of the object beam can be converted into the spectrum IOBJ(λ) of the object beam.

[0064] The calculation device 70 calculates the transmission spectrum T(λ) of the measurement object M based on the ratio IOBJ(λ) / IREF(λ) of the two spectra IOBJ(λ) and IREF(λ). The optical characteristics of the measurement object M are expressed by this transmission spectrum T(λ).

[0065] If the relationship of wavelength λ to time t in wavelength swept light is expressed by a function λ=f(t), then most simply, the wavelength λ changes linearly with respect to time t according to a linear function. This means that when the time waveform IOBJ(t) of the object light drops at a certain time tx, the transmission spectrum T(λ) has an absorption spectrum at wavelength λx=f(tx).

[0066] Note that the processing in the calculation device 70 is not limited to this. After calculating the ratio T(t)=IOBJ(t) / IREF(t) of two time waveforms IOBJ(t) and IREF(t), the transmission spectrum T(λ) may be calculated by converting the variable t of this time waveform T(t) to λ.

[0067] The control device 65 and the arithmetic device 70 are configured from a computer including a CPU, RAM, ROM, etc., and may be configured from separate computers or may be configured from a single computer.

[0068] According to the light measurement device 1 of this embodiment having the above configuration, the optical characteristics of the measurement object M are measured as follows.

[0069] First, under the control of the control device 65, the vibrating feeder 4, the alignment table 6, and the exhaust pump 17 and the drive motor 22 of the conveying device 10 are driven, and the measurement objects M put into the hopper 3 are aligned in a line by passing through the vibrating feeder 4 and the alignment table 6 in sequence, and are supplied to the conveying device 10 in this aligned state. Then, the measurement objects M sequentially supplied to the conveying device 10 are adsorbed and conveyed in a state straddling the conveying belts 15, 16. Therefore, the measurement objects M are conveyed in a stable posture, and are conveyed on the adsorption conveying path without deviating from the adsorption conveying path.

[0070] The control device 65 also drives the light source device 35 to emit the wavelength swept light. The wavelength swept light emitted from the light source device 35 is split into two light beams by the beam splitter 41, one of which is transmitted in the emission direction as it is to become the measurement light, and the other is reflected and received by the reference light receiving device 50 as the reference light. At this time, the galvanometer mirror 42 is in a position where the reflected measurement light takes an optical path (avoidance optical path) (optical path shown by two-dot chain lines in FIGS. 5 and 6) that does not pass through the slit hole of the slit member 44 (position shown by two-dot chain lines in FIGS. 5 and 6). Therefore, at this time, the measurement light is not incident on the measurement light receiving device 51.

[0071] Then, when the control device 65 receives a detection signal from the object detection sensor 55 after the measurement object M detected by the object detection sensor 55 is detected by the conveying device 10, the control device 65 calculates the time (timing) from the time of detection of the measurement object M detected by the object detection sensor 55 to the measurement position P based on the rotational speed of the drive motor 22 detected by the rotary encoder 23, and when the calculated time has elapsed, drives the motor 43 to switch the optical path of the measurement light reflected by the galvanometer mirror 42 to an optical path (irradiation optical path) that passes through the slit hole in the slit member 44.

[0072] As a result, the measurement light is sequentially reflected by the first mirror 45 and the second mirror 46, and is incident on the measurement object M at the measurement position P. After passing through the measurement object M, the measurement light is received by the measurement light receiving device 51 as object light. Next, the control device 65 maintains the optical path of the measurement light as the irradiation optical path until the measurement object M passes the measurement position P, and then drives the motor 43 again to switch the optical path of the measurement light reflected by the galvanometer mirror 42 to an optical path (light-shielding optical path) that does not pass through the slit hole of the slit member 44 shortly before the measurement object M passes the measurement position P. As a result, the measurement light is irradiated to the measurement position P only when the measurement object M is at the measurement position P, and when the measurement object M is not at the measurement position P, the measurement light is not irradiated to the measurement position P.

[0073] Since the measurement object M is transported in a stable posture to the measurement position P by suction and transport, the measurement light can be reliably irradiated onto the measurement object M at the measurement position P. Since the measurement object M is transported by suction straddling the transport belts 15, 16, the measurement light passes between the transport belts 15, 16, transmits only the measurement object M, and is received by the measurement light receiving device 51.

[0074] When the object light is received by the measurement light receiving device 51, an output signal is transmitted from the measurement light receiving device 51 to the calculation device 70, and the calculation device 70 measures the optical characteristics of the measurement object M based on the output signal of the object light received from the measurement light receiving device 51 and the output signal of the reference light received from the reference light receiving device 50, determines whether the characteristics are good or bad, and transmits the determination result to the control device 65.

[0075] Then, the control device 65 drives the sorting and recovery mechanism of the sorting device 60 based on the judgment result received from the calculation device 70 to recover non-defective products in a non-defective product recovery room and recover defective products in a defective product recovery room. The control device 65 calculates the time (timing) from the time of detection of the measurement object M detected by the object detection sensor 55 until it reaches the sorting and recovery mechanism based on the conveying speed of the measurement object M and the previously acquired distance between the detection position of the object detection sensor 55 and the sorting and recovery mechanism, and drives the sorting and recovery mechanism when the corresponding measurement object M reaches the sorting and recovery mechanism.

[0076] By the above operation, the optical characteristics of the measurement objects M transported in a random order by the transport device 10 are measured in sequence, and the objects are sorted into non-defective and defective based on the measurement results.

[0077] In this way, according to the optical measurement device 1 of this example, only when the measurement object M is at the measurement position P, the measurement light is irradiated to the measurement position P and received by the measurement light receiving device 51, and when the measurement object M is not at the measurement position P, the measurement light is not irradiated to the measurement position P, in other words, it is possible to prevent the measurement light receiving device 51 from receiving the high-power wavelength swept light as it is, and it is possible to avoid damage to the measurement light receiving device 51 due to the wavelength swept light being received as it is by the measurement light receiving device 51.

[0078] The effect of the light measurement device 1 was verified as follows. The beam diameter of the wavelength swept light (measurement light) emitted from the light source device 35 was set to 0.8 mm (1 / e 2 The diameter of the slit member 44 was set to 1 mm, and the width of the slit hole of the slit member 44 was set to 2 mm. The distance (retraction distance) between the irradiation light path and the light blocking light path on the lower surface of the slit member 44 was set to 3 mm.

[0079] When the light intensity incident on the measurement light receiving device 51 was measured for each of the cases where the measurement light path was the irradiated light path and the blocked light path with no measurement target M present at the measurement position P, the incident intensity was 58 mW in the irradiated light path, whereas the incident intensity was 12 μW in the blocked light path, decreasing to 0.021%. This is a value sufficiently below the allowable input (damage threshold) of the measurement light receiving device 51.

[0080] The slit width and retraction distance of the slit member 44 can be determined experimentally taking into account the damage threshold of the measurement light receiving device 51, the beam diameter of the measurement light, and the performance (speed) of the optical path switching unit (galvanometer mirror 42 and motor 43).

[0081] Although one embodiment of the present invention has been described above, the specific aspects that the present invention can adopt are not limited to the above example.

[0082] For example, in the above example, the slit member 44 that functions as an aperture is provided, but the present invention is not limited to this configuration, and if the intensity of light incident on the measurement light receiving device 51 can be sufficiently reduced when the optical path of the measurement light is set as the evacuation optical path, such an aperture does not have to be provided. However, providing an aperture can prevent the measurement light from becoming stray light.

[0083] In the above example, the optical path of the measurement light is switched between the irradiation optical path and the retreat optical path by the optical path switching unit composed of the galvanometer mirror 42 and the motor 43, but the present invention is not limited to this configuration. For example, as shown in FIG. 9, an irradiation device 41' may be provided in which a third mirror 47 is provided instead of the galvanometer mirror 42 and a light blocking member 48 that switches between a transmission state and a non-transmission state is provided instead of the slit member 44. The optical measurement device 1' of this example differs from the optical measurement device 1 described above only in this configuration, and the other configurations are the same as those of the optical measurement device 1. For this reason, in FIG. 9, the same reference numerals are used for the same configurations as those of the optical measurement device 1 of the above example shown in FIG. 6. The non-transmission state includes not only the case where the transmission of light is completely blocked, but also the mode where the transmitted light is dimmed.

[0084] In this optical measurement device 1', when the control device 65 receives a detection signal from the object detection sensor 55 after the measurement object M sequentially transported by the transport device 10 is detected by the object detection sensor 55, it calculates the time (timing) from the time of detection of the measurement object M detected by the object detection sensor 55 to the measurement position P based on the rotational speed of the drive motor 22 detected by the rotary encoder 23, as in the above example, and switches the light-shielding member 48, which is in an opaque state, to a transparent state when the calculated time has elapsed.

[0085] As a result, the measurement light reflected by the third mirror 47 passes through the light-shielding member 48, is reflected successively by the first mirror 45 and the second mirror 46, and is incident on the measurement object M located at the measurement position P, and after passing through the measurement object M, is received as object light by the measurement light receiving device 51. On the other hand, when the light-shielding member 48 is in the non-transmitting state, the measurement light reflected by the third mirror 47 is blocked by the light-shielding member 48 and does not reach the measurement position P in its current state.

[0086] Then, the control device 65 maintains the light blocking member 48 in the transmitting state until the measurement object M passes the measurement position P, and then switches the light blocking member 48 to the non-transmitting state again shortly before the measurement object M passes the measurement position P. As described above, the measurement light is irradiated to the measurement position P only when the measurement object M is at the measurement position P, and when the measurement object M is not at the measurement position P, the measurement light is not irradiated to the measurement position P, or the measurement light irradiated to the measurement position P can be reduced.

[0087] Thus, even with the optical measuring device 1' having such a configuration, it is possible to prevent high-power wavelength swept light from being received directly by the measurement light receiving device 51, and it is possible to avoid damage to the measurement light receiving device 51 due to the wavelength swept light being received directly by the measurement light receiving device 51.

[0088] The light blocking member 48 may be, for example, a movable shutter or a variable attenuator, and the variable attenuator may be, for example, a liquid crystal shutter, an acousto-optical modulator (AOM), an electro-optical modulator (EOM), or the like.

[0089] In addition, in each of the above examples, the control device 65 calculates the conveying speed of the measurement object M conveyed by the conveying belts 15, 16 based on the rotational speed of the drive motor 22 detected by the rotary encoder 23, and calculates the time (timing) from the time point of detection of the measurement object M detected by the object detection sensor 55 to the measurement position P based on the calculated conveying speed and the distance between the detection position of the object detection sensor 55 and the measurement position P obtained in advance, but the estimation of the timing of the measurement object M reaching the measurement position P from the time point of detection is not limited to such a method.

[0090] For example, as described above, the rotary encoder 23 detects the rotation angle per unit time of the drive motor 22, and therefore can detect the amount of movement of the conveyor belts 15, 16, in other words, the amount of movement of the object to be measured M, and based on this amount of movement, the timing at which the object to be measured M reaches the measurement position P from the time of detection can be estimated. [Explanation of symbols]

[0091] 1. Light measuring device 2 Supply section 3. Hopper 4. Vibration feeder 5 Shoot 6 Alignment Table 10. Conveyor 11 Suction box 11a Through hole 12 Slit 13,14 Guide groove 15,16 Conveyor belt 17 Exhaust Pump 18 Drive pulley 19, 20, 21 Driven pulley 22 Drive motor 23 Rotary encoder (speed detection sensor) 24 Cover body 24a through hole 25 Glass Plate 30 Cover body 35 Light source device 40 Irradiation device 41 Beam splitter 42 Galvano Mirror 43 Motor 44 Slit member 45 1st Mirror 46 2nd Mirror 50 Reference light receiver 51 Light receiving device 55 Object detection sensor 60 Sorting Equipment 65 Control device 70 Arithmetic unit

Claims

1. a light source device that generates wavelength swept light; a conveying device including two endless annular conveying belts arranged opposite to each other to form a linear conveying path, and a driving unit for rotating the conveying belts, and conveying a measurement object along the conveying path while the measurement object is straddled between the two conveying belts; an irradiation device having an optical path for guiding and irradiating the wavelength swept light generated by the light source device to a measurement position set on the transport path, the irradiation device having an optical path switching unit provided on the optical path for switching the optical path of the wavelength swept light; a light receiving device that receives the wavelength swept light irradiated onto the measurement position by the irradiating device; an object detection sensor provided upstream of the measurement position in a conveying direction of the conveying device, the object detection sensor detecting a measurement object conveyed by the conveying device; a conveyance detection sensor for detecting a conveyance speed or a conveyance direction displacement of the conveyor belt; A control device that controls a drive unit of the transport device and an optical path switching unit of the irradiation device, The control device estimates the timing when the object to be measured will reach the measurement position based on detection by the object detection sensor and the displacement in the conveying direction or the conveying speed detected by the conveying detection sensor, and controls the optical path switching unit in synchronization with the estimated timing to set an optical path in which the wavelength swept light is received by a light receiving device while the object to be measured is present at the measurement position, and sets an optical path in which the wavelength swept light is not received by a light receiving device while the object to be measured is not present at the measurement position.

2. 2. The optical measurement device according to claim 1, wherein the optical path switching unit includes any one of a galvanometer mirror, a MEMS (Micro Electro Mechanical Systems) mirror, a piezoelectric driven mirror, and a polygon mirror.

3. 3. The light measurement device according to claim 2, wherein the irradiation device further comprises an aperture on the exit side of the light path switching portion.

4. a light source device that generates wavelength swept light; a conveying device including two endless annular conveying belts arranged opposite to each other to form a linear conveying path, and a driving unit for rotating the conveying belts, and conveying a measurement object along the conveying path while the measurement object is straddled between the two conveying belts; an irradiation device having an optical path for guiding and irradiating the wavelength swept light generated by the light source device to a measurement position set on the transport path, and having a light blocking portion provided on the optical path for switching between transmitting and blocking the wavelength swept light; a light receiving device that receives the wavelength swept light irradiated onto the measurement position by the irradiating device; an object detection sensor provided upstream of the measurement position in a conveying direction of the conveying device, the object detection sensor detecting a measurement object conveyed by the conveying device; a conveyance detection sensor for detecting a conveyance speed or a conveyance direction displacement of the conveyor belt; A control device that controls a drive unit of the transport device and a light blocking unit of the irradiation device, The control device is an optical measurement device configured to estimate the timing when the object to be measured will reach the measurement position based on detection by the object detection sensor and the displacement in the conveying speed or conveying direction detected by the conveying detection sensor, and to control the shading part in synchronization with the estimated timing to make the shading part transparent while the object to be measured is present at the measurement position, and to make the shading part opaque while the object to be measured is not present at the measurement position.

5. 5. The optical measurement device according to claim 4, wherein the light blocking portion includes one of a movable shutter and a variable attenuator.

6. 6. The optical measurement device according to claim 5, wherein the variable attenuator includes any one of a liquid crystal shutter, an acousto-optic modulator, and an electro-optic modulator.

7. 7. The optical measurement device according to claim 1, wherein the wavelength swept light passes between the two conveyor belts and is irradiated onto the measurement object.

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