Light measuring device

Abstract

To provide an optical measuring device capable of increasing the light intensity of the reference light used in reference measurements. [Solution] The optical measuring device 1 according to the present disclosure comprises an irradiation unit 10 that irradiates an object to be measured S with irradiation light L1, a light receiving unit 30 that receives the light to be measured L2 from the object to be measured S based on the irradiation light L1 on the same side as the irradiation unit 10, and a calibration unit 40 used for reference measurement, which has a standard member 41 that propagates at least a portion of the irradiation light L1 as reference light L3 toward the light receiving unit 30 and a first optical element 42 that focuses the irradiation light L1 onto the standard member 41, and the calibration unit 40 transitions between a first state for reference measurement, in which it is positioned in conjunction with the optical path of the irradiation light L1 between the irradiation unit 10 and the light receiving unit 30 and the object to be measured S, and a second state for measuring the object to be measured, in which it is positioned away from the optical path.

Description

Technical Field

[0001] The present disclosure relates to an optical measurement device.

Background Art

[0002] Conventionally, techniques for measuring the optical properties of a measurement target have been known. For example, in Patent Document 1, there is disclosed a spectroscopic measurement device that is small, excellent in portability and durability, capable of highly sensitive measurement, can obtain spectral information mainly composed of diffuse reflection components with the effects of specular reflection, diffuse reflection, and stray light removed, and can easily measure a target with a small measurement area.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology, in a state where the irradiation light from the light source is condensed on the measurement target, at the time of reference measurement, a standard white plate is inserted at a position largely separated in front of the measurement target. As a result, since the standard white plate diffusely reflects the irradiation light at a position largely deviated from the condensing position of the irradiation light, the amount of reference light for reference measurement incident on the light receiving system has been reduced.

[0005] An object of the present disclosure is to provide an optical measurement device capable of increasing the amount of reference light in reference measurement.

Means for Solving the Problems

[0006] Some embodiments of the optical measuring apparatus include an illumination unit that illuminates an object to be measured with illumination light, a light receiving unit that receives light to be measured from the object to be measured based on the illumination light on the same side as the illumination unit, and a calibration unit used for reference measurement, the calibration unit having a standard member that propagates at least a portion of the illumination light toward the light receiving unit as reference light, and a first optical element that focuses the illumination light onto the standard member, wherein the calibration unit transitions between a first state in the reference measurement, where it is positioned in conjunction with the optical path of the illumination light between the illumination unit and the light receiving unit and the object to be measured, and a second state in the measurement of the object to be measured, where it is positioned away from the optical path.

[0007] This allows the optical measuring device to increase the amount of reference light used in reference measurements. Unlike conventional technology, the optical measuring device can position the focal point of the illuminated light on the object being measured during measurement, while positioning the focal point of the illuminated light on the standard component during reference measurements. Therefore, the optical measuring device can receive light with sufficient intensity in both the measurement of the object being measured and the reference measurement. For example, even when the distance from the light source to the object being measured and the distance from the light source to the standard component differ significantly, such as by 10 mm or more, the optical measuring device can position the focal point of the illuminated light on the object being measured and the standard component, respectively.

[0008] In one embodiment of the optical measuring device, the first optical element may, in the first state, position the focal point of the irradiated light on the standard member on the optical axis of the light receiving unit. This allows the optical measuring device to position the focal point of the irradiated light on the optical axis of the light receiving unit not only when measuring the object under measurement, but also when performing reference measurements. For example, when measuring the object under measurement, the optical measuring device positions the focal point of the irradiated light in a region including the intersection of the optical axis of the light receiving unit and the object under measurement. On the other hand, when performing reference measurements, the optical measuring device positions the focal point of the irradiated light in a region including the intersection of the optical axis of the light receiving unit and the standard member. As a result, the optical measuring device can receive light with sufficient light intensity in any measurement.

[0009] In one embodiment of the optical measuring device, the optical axis of the first optical element may coincide with the optical axis of the light receiving unit in the first state. This allows the optical measuring device to arrange the first optical element symmetrically with respect to the optical axis. The optical measuring device can also arrange the calibration unit, which includes the first optical element, symmetrically with respect to the optical axis. Therefore, the optical measuring device can improve the symmetry of the optical system, and as a result, facilitate assembly work by workers on the optical system.

[0010] In one embodiment of the optical measuring device, the irradiation unit may have a plurality of light sources, each emitting the irradiation light. This allows the optical measuring device to increase the amount of light to be measured from the object to be measured during measurement, and to receive light with sufficient intensity. Similarly, in reference measurement, the optical measuring device can increase the amount of reference light from a standard component, and to receive light with sufficient intensity.

[0011] In one embodiment of the optical measuring device, the plurality of light sources may be arranged rotationally symmetrically with respect to the optical axis of the light receiving unit. This allows the optical measuring device to arrange the plurality of light sources symmetrically with respect to the optical axis. The optical measuring device allows the illumination unit, which includes the plurality of light sources, to be arranged symmetrically with respect to the optical axis. Therefore, the optical measuring device can improve the symmetry of the optical system, and as a result, facilitates assembly work by workers and others involved in the optical system.

[0012] In one embodiment of the optical measuring device, the calibration unit may have a plurality of first optical elements, each of which is positioned relative to the plurality of light sources in the first state. This allows the optical measuring device to propagate reference light from a standard member in the space between the plurality of first optical elements. Therefore, the optical measuring device can propagate reference light from a standard member to the light receiving unit while reducing the influence of optical effects from the first optical elements. Consequently, the optical measuring device can reduce the difference between the optical system during measurement of the object under measurement in the second state, when the calibration unit is not inserted into the optical system, and the optical system during reference measurement.

[0013] In one embodiment of the optical measuring device, the first optical element may have a through hole positioned to coincide with the optical axis of the light-receiving unit in the first state. This allows the optical measuring device to propagate the reference light from the standard member to the light-receiving unit while reducing the influence of the optical effect from the first optical element. Therefore, the optical measuring device can reduce the difference between the optical system during measurement of the object under measurement in the second state, when the calibration unit is not inserted into the optical system, and the optical system during reference measurement.

[0014] In one embodiment of the optical measuring device, the diameter of the through-hole may be greater than or equal to the diameter of the reference light when the reference light from the standard member, which is received by the light-receiving unit in the first state, passes through the first optical element. This allows the optical measuring device to propagate the reference light from the standard member to the light-receiving unit while further reducing the influence of the optical effect from the first optical element. Therefore, the optical measuring device can reduce the difference between the optical system during measurement of the object under measurement in the second state, when the calibration unit is not inserted into the optical system, and the optical system during reference measurement.

[0015] In one embodiment of the optical measuring device, the through-hole may have a shape that tapers in reverse from the standard member side toward the light-receiving part side. This allows the optical measuring device to propagate even reference light, whose diameter gradually widens from the standard member toward the light-receiving part, to the light-receiving part while reducing the influence of optical effects from the first optical element. Therefore, the optical measuring device can reduce the difference between the optical system during measurement of the object under measurement in the second state, when the calibration unit is not inserted into the optical system, and the optical system during reference measurement.

[0016] In one embodiment of the optical measuring device, the calibration unit may further include a second optical element positioned on top of the through-hole, which guides the reference light from the standard member to the light-receiving unit in the first state. This allows the optical measuring device to guide the reference light from the standard member to the light-receiving unit via the second optical element located in the through-hole. Therefore, by appropriately setting the numerical aperture of the second optical element, the optical measuring device can also focus a large amount of reference light onto the light-receiving unit during reference measurement.

[0017] In one embodiment of the optical measuring device, the calibration unit may further include a second optical element positioned between the first optical element and the standard member, which guides the reference light from the standard member to the light receiving unit in the first state. This allows the optical measuring device to guide the reference light from the standard member to the light receiving unit via the second optical element located between the first optical element and the standard member. Therefore, by appropriately setting the numerical aperture of the second optical element, the optical measuring device can also focus a large amount of reference light onto the light receiving unit during reference measurement.

[0018] In one embodiment of the light measuring device, the optical axis of the second optical element may coincide with the optical axis of the light receiving unit in the first state. This makes it possible for the light measuring device to focus a large amount of reference light onto the light receiving unit 30 during reference measurement.

[0019] The optical measurement device in one embodiment may further include a housing that integrally houses the irradiation unit and the calibration unit in the first state. As a result, inside the housing of the optical measurement device, the calibration unit can be positioned between the irradiation unit, the light-receiving unit, and the optical window, and the reference measurement can be completed inside the housing. Therefore, in the reference measurement, the optical measurement device as a measurement probe can be removed from the production line including piping and tanks, etc., without removing the optical measurement device as a measurement probe from the production line, and the light-receiving unit including the spectroscopic sensor can receive the reference light inside the housing. The optical measurement device can easily shift to the reference measurement while maintaining the setup in the measurement of the measurement target. As a result, the convenience of the optical measurement device is improved.

Effects of the Invention

[0020] According to the present disclosure, it is possible to provide an optical measurement device capable of increasing the amount of light of the reference light in the reference measurement.

Brief Description of the Drawings

Modes for Carrying Out the Invention

[0024] In this case, it is not easy to replace the object being measured with a reference measurement component, such as a standard diffuse reflector, at the location of the object being measured inside the pipe or container. Therefore, as an alternative, a reference measurement is performed by inserting a component such as a standard diffuse reflector into the optical system of a light sensor probe installed outside the optical window.

[0025] For example, in the prior art described in Patent Document 1, the spectroscopic measuring device irradiates a sample or other object to be measured with light through a window member and receives diffusely reflected light from the object to be measured. The spectroscopic measuring device guides the diffusely reflected light to a spectroscopic sensor or the like to measure the scattering characteristics and absorption characteristics of the object to be measured. In addition, when performing a reference measurement for calibration, the spectroscopic measuring device inserts a standard whiteboard into the optical system and irradiates the standard whiteboard with measurement light.

[0026] However, window components can crack and break due to aging, accidents during manufacturing, and disasters such as earthquakes. When window components crack, it can lead to increased human costs for collecting the fragments, the disposal of raw materials that may have been contaminated with the fragments, and loss of consumer trust if foreign matter contamination occurs. For example, in industries that manufacture products where foreign matter contamination is a serious problem, such as food and cosmetics, the use of window components itself is an undesirable factor.

[0027] Given the above background, the introduction of optical sensors into the manufacturing process requires the placement of window components with high impact resistance and durability. Therefore, tempered glass and sapphire with a thickness of approximately 10 mm or more are used as window components for optical probes facing the object being measured, or for window components used in containers such as pipes or tanks.

[0028] As a result, when a standard white plate and a standard diffuse reflector are inserted on the light source side of the window member during reference measurement, as in the prior art described in Patent Document 1, the distance from the point of focus of the irradiated light on the object under measurement to the said member differs significantly compared to when the object under measurement is being measured. For example, the distance between the member used during reference measurement and the object under measurement, where the irradiated light is focused, is expected to be about 10 mm or more.

[0029] For example, in the case of an optical system where the optical axis of the irradiating unit and the optical axis of the light receiving unit do not coincide but are offset from each other by a predetermined angle, even if the focusing position of the irradiated light is aligned with the optical axis of the light receiving unit during one of the measurements, such as the reference measurement or the measurement of the object under measurement, the irradiated light will not be focused with the optical axis of the light receiving unit during the other measurement, making it difficult to guide sufficient light to the light receiving unit.

[0030] This disclosure aims to provide an optical measuring device capable of increasing the amount of reference light in reference measurements in order to solve the above-mentioned problems. For example, this disclosure aims to provide an optical measuring device as an optical sensor probe that can position the focal point of the irradiated light on the optical axis of the light receiving unit and receive light with sufficient light intensity, not only when measuring the object to be measured, such as a sample, but also when performing reference measurements.

[0031] In the following, one embodiment of this disclosure will be mainly described with reference to the attached drawings.

[0032] (First Embodiment) Figure 1 is a schematic diagram showing a first example of the configuration of the optical measuring device 1 according to the first embodiment of this disclosure. Figure 1 shows the configuration of the optical measuring device 1 when measuring an object S under measurement. Figure 2 is a schematic diagram showing a second example of the configuration of the optical measuring device 1 according to the first embodiment of this disclosure. Figure 2 shows the configuration of the optical measuring device 1 during reference measurement, in contrast to the configuration of the optical measuring device 1 during measurement of an object S under measurement shown in Figure 1. In Figures 1 and 2, the refraction of light in the lens and window shown as an example of the configuration of the optical measuring device 1 is simplified for the purpose of simple illustration in the drawings. An example of the configuration and function of the optical measuring device 1 according to the first embodiment will be mainly described with reference to Figures 1 and 2.

[0033] The optical measuring device 1 according to the first embodiment measures the optical properties of an object to be measured, such as a sample, as an optical sensor probe. More specifically, the optical measuring device 1 irradiates the object to be measured, S, located in a predetermined area, with illumination light L1 through an optical window W. The optical measuring device 1 receives the light to be measured L2 from the object to be measured S based on the illumination light L1. The optical measuring device 1 measures the optical properties of the object to be measured S based on the received light to be measured L2.

[0034] In this disclosure, “predetermined area” includes, for example, any space having the function of storing or transporting the object to be measured S. The predetermined area includes, for example, the internal space of a container such as a tank and piping. “Optical window W” includes, for example, any window having the function of transmitting light at the wavelength of the irradiation light L1 used by the optical measuring device 1 in order for the optical measuring device 1 to measure the optical properties of the object to be measured S located in the predetermined area using light. The optical window W is made of a material such as glass, sapphire, acrylic resin, and diamond. The optical window W has a thickness of 10 mm or more, for example, to sufficiently increase impact resistance and pressure resistance. The optical window W is attached, for example, to the side, top, or bottom surface of a container such as a tank and piping that includes the predetermined area, and transmits the irradiation light L1 from the outside toward the predetermined area.

[0035] "Object to be measured S" includes any object such as a solid, liquid, or slurry. Object to be measured S includes, for example, an object that produces diffuse reflection when the optical measuring device 1 measures the optical properties of object to be measured S using the diffuse reflection method. "Optical properties" include the wavelength dependence of the reflectance of light. "Light to be measured L2" includes reflected light such as diffuse reflected light that propagates backward from object to be measured S onto which the irradiated light L1 was irradiated. "Towards backward" means, for example, the direction in which the irradiated light L1 is folded back from the direction in which it propagates, and toward the light receiving unit 30 located inside the housing 50, which will be described later. Light to be measured L2 represents the optical properties of object to be measured S. As an example, the optical measuring device 1 measures the optical properties of object to be measured S, such as the reflectance spectrum of light, by receiving light to be measured L2 and using the diffuse reflection method.

[0036] The light measuring device 1 includes an irradiation unit 10, a light guide unit 20, a light receiving unit 30, a calibration unit 40, a housing 50, a storage unit 60, an input unit 70, an output unit 80, and a control unit 90.

[0037] The irradiation unit 10 irradiates the object to be measured S with irradiation light L1. The irradiation unit 10 has a light source 11 such as a lamp, a light-emitting diode (LED), and a laser. The lamp includes halogen lamps, tungsten lamps, and xenon lamps. The irradiation light L1 has a wavelength that matches the optical characteristics of the object to be measured S to be measured using the optical measuring device 1. The wavelength of the irradiation light L1 irradiated by the irradiation unit 10 includes, for example, wavelengths that are reflected, scattered, or absorbed by the object to be measured S. The wavelength of the irradiation light L1 includes, for example, the ultraviolet region, the visible region, the near-infrared region, and other infrared regions.

[0038] The illumination unit 10 has an optical element 12 that guides the illumination light L1 emitted from the light source 11 toward the object to be measured S. The optical element 12 includes elements such as a single lens, a combination of multiple lenses, a prism, and a mirror. The optical element 12 receives the illumination light L1 emitted from the light source 11 and focuses it toward the object to be measured S.

[0039] The irradiation unit 10 has a plurality of light sources 11, each emitting irradiation light L1. The output characteristics of the plurality of light sources 11, such as light intensity and wavelength, may be the same or different. The irradiation unit 10 arranges optical elements 12 for each light source 11, corresponding to the number of light sources 11. In Figures 1 and 2, two sets of light sources 11 and optical elements 12 are shown as an example, but there may be only one set of light sources 11 and optical elements 12, or three or more sets. The number of light sources 11 and optical elements 12 is not limited to a configuration where they are the same, but may be different from each other.

[0040] The multiple light sources 11 are arranged, for example, rotationally symmetrically with respect to the optical axis A of the light receiving unit 30. Similarly, the multiple optical elements 12 are arranged rotationally symmetrically with respect to the optical axis A of the light receiving unit 30. For example, in Figures 1 and 2, as an example, two sets of light sources 11 and optical elements 12 are arranged rotationally symmetrically with respect to the optical axis A of the light receiving unit 30. The two sets of light sources 11 and optical elements 12 are arranged rotationally symmetrically on a circle centered on the optical axis A of the light receiving unit 30.

[0041] The light guide unit 20 includes an optional optical window that guides the irradiation light L1 emitted from the irradiation unit 10 to the outside of the housing 50. This optical window is attached to the housing 50 as a probe window and separates the inside from the outside of the housing 50. The light guide unit 20 transmits the irradiation light L1 emitted from the irradiation unit 10 and propagates it through the optical window W to the object under measurement S. The light guide unit 20 transmits the light to be measured L2 that has propagated from the object under measurement S through the optical window W and receives it inside the housing 50. The light guide unit 20 propagates the light to be measured L2 from the object under measurement S to the light receiving unit 30. The light guide unit 20 has the function of guiding the irradiation light L1 from the irradiation unit 10 to the object under measurement S and the function of guiding the light to be measured L2 from the object under measurement S to the light receiving unit 30.

[0042] The light-receiving unit 30 receives the light to be measured L2 from the object to be measured S, based on the irradiation light L1 irradiated onto the object to be measured S by the irradiation unit 10, on the same side as the irradiation unit 10. The light-receiving unit 30 receives the light to be measured L2 from the object to be measured S, which is incident via the light guide unit 20, converts it into an electrical signal, and outputs it to the control unit 90 or the like. The light-receiving unit 30 has, for example, a spectroscopic sensor 31. The wavelength range that can be received by the spectroscopic sensor 31 of the light-receiving unit 30 includes the wavelength range of the light to be measured L2. The spectroscopic sensor 31 of the light-receiving unit 30 has light-receiving sensitivity at the wavelength of the light to be measured L2. The light-receiving unit 30 has a spectroscopic function due to the spectroscopic sensor 31.

[0043] The light-receiving unit 30 has an optical element 32 that guides the light L2 to be measured from the object to be measured S toward the spectroscopic sensor 31. The optical element 32 includes elements such as a single lens, a combination of multiple lenses, a prism, and a mirror. The optical element 32 receives the light L2 to be measured from the object to be measured S and focuses it toward the light guide component 33.

[0044] The light receiving unit 30 has a light guide component 33 that guides the light L2 to be measured from the object to be measured S, which has been focused by the optical element 32, to the spectroscopic sensor 31. The light guide component 33 includes optical components such as optical fibers, optical couplers, optical conduits, and mirrors. For example, the light guide component 33 receives the light L2 to be measured that has passed through the optical element 32 inside the housing 50 and guides it to the spectroscopic sensor 31 located outside the housing 50.

[0045] The calibration unit 40 is used for reference measurement. The calibration unit 40 transitions between a first state in reference measurement, where it is positioned in the optical path of the irradiated light L1 between the irradiation unit 10 and the light receiving unit 30 and the object to be measured S, and a second state in measurement of the object to be measured S, where it is positioned away from the optical path.

[0046] In this disclosure, "first state" means a state in which, for example, the optical arrangement of the calibration unit 40 as shown in Figure 2, the standard member 41 of the calibration unit 40 is blocking the irradiated light L1 in front of the light guide unit 20 inside the housing 50. "Reference measurement" means a measurement performed using the calibration unit 40 to correct, for example, the output characteristics of the irradiated light L1 of the irradiation unit 10, such as the amount and wavelength of the irradiated light, and the light receiving characteristics of the spectroscopic sensor 31 of the light receiving unit 30, such as the light receiving sensitivity, when these change or fluctuate over time during the measurement of the object S under measurement.

[0047] In this disclosure, "second state" means a state in which the standard member 41 of the calibration unit 40 does not obstruct the irradiated light L1 in front of the light guide unit 20, allowing it to propagate to the object to be measured S, for example, corresponding to the optical arrangement of the calibration unit 40 as shown in Figure 1. "Measurement of the object to be measured S" means, for example, a measurement in which the optical measuring device 1, acting as an optical sensor probe, acquires information about the optical properties of the object to be measured S, such as a sample to be measured.

[0048] The calibration unit 40 may be inserted into the probe optical system of the optical measuring device 1 in any manner of movement, such as sliding and rotating. For example, the calibration unit 40 may be inserted into the probe optical system by any drive mechanism, such as an electrically driven sliding mechanism and a rotating mechanism, which connects the housing 50 and the calibration unit 40 to each other. This drive mechanism may be operated automatically by a control device, including a control unit 90, in conjunction with measurements using the spectroscopic sensor 31, including measurements of the object to be measured S and reference measurements. However, the calibration unit 40 may also be inserted into the probe optical system by manual operation by the user without relying on a drive mechanism.

[0049] The calibration unit 40 has a standard member 41 that propagates at least a portion of the irradiated light L1 as reference light L3 toward the light receiving unit 30 in the first state. In this disclosure, "reference light L3" includes reflected light such as diffuse reflected light propagating backward from the standard member 41 irradiated with the irradiated light L1. The standard member 41 includes, for example, any member whose light reflectivity is approximately 100%. The standard member 41 includes standard diffuse reflectors and standard white plates that have the function of reflecting light with high reflectivity. The material constituting the standard member 41 may include metals such as barium sulfate, Teflon®, gold, and aluminum. The standard member 41 may be flat as shown in Figures 1 and 2, or it may have a bowl shape with a recess on the optical element 32 side.

[0050] The calibration unit 40 has an optical element 42 that focuses the irradiated light L1 onto the standard member 41 in the first state. The optical element 42 corresponds to the "first optical element" in the claims. The optical element 42 includes elements such as a single lens, a combination of multiple lenses, a prism, and a mirror. The optical element 42 receives the irradiated light L1 from the irradiation unit 10 and focuses it onto the surface of the standard member 41. The optical element 42 is arranged, for example, parallel to the standard member 41.

[0051] In the first state shown in Figure 2, the optical element 42 positions, for example, the focal point of the irradiated light L1 on the standard member 41 on the optical axis A of the light receiving unit 30. In the first state shown in Figure 2, the optical axis of the optical element 42 coincides, for example, with the optical axis A of the light receiving unit 30. The calibration unit 40 is inserted into the probe optical system, for example, so that the center of the optical element 42 coincides with the optical axis A of the light receiving unit 30, which is the probe light receiving optical system.

[0052] The calibration unit 40 focuses the irradiated light L1 into a region including the intersection point of the standard member 41 and the optical axis A of the light receiving unit 30, for example, by refraction of light by the optical element 42. The calibration unit 40 guides the reference light L3, which is diffusely reflected light from the standard member 41, to the optical element 32 of the light receiving unit 30 via the optical element 42. The reference light L3 is focused by the optical element 32 to the light guide component 33 and guided to the spectral sensor 31 by the light guide component 33.

[0053] The housing 50 integrally houses the irradiation unit 10 and the calibration unit 40 in the first state. In the second state shown in Figure 1, the housing 50 positions the probe optical system, which includes at least a part of the irradiation unit 10 and the light receiving unit 30, as the probe housing. The housing 50 positions the light guide unit 20, which serves as the probe window, as the exit end of the irradiation light L1, on a part of its side surface.

[0054] The storage unit 60 includes storage devices such as an HDD (Hard Disk Drive), SSD (Solid State Drive), EEPROM (Electrically Erasable Programmable Read-Only Memory), ROM (Read-Only Memory), and RAM (Random Access Memory). The storage unit 60 stores information necessary to realize the operation of the optical measuring device 1. The storage unit 60 also stores information obtained through the operation of the optical measuring device 1. For example, the storage unit 60 stores system programs, application programs, and various data acquired by any means such as communication.

[0055] The storage unit 60 may function as a main memory, auxiliary memory, or cache memory. The storage unit 60 is not limited to one built into the optical measuring device 1, but may also include an external storage device connected by a digital input / output port such as USB (Universal Serial Bus).

[0056] The input unit 70 includes one or more input interfaces that detect user input and acquire input information based on user operations. These input interfaces include physical keys, capacitive keys, a touchscreen integrated with the display of the output unit 80, an imaging module such as a camera, and a microphone that accepts voice input.

[0057] The output unit 80 includes one or more output interfaces that output information to notify the user. These output interfaces include a display that outputs information as an image, a speaker that outputs information as sound, and a vibrator that outputs information as vibration. The display includes LCD (Liquid Crystal Display) and organic EL (Electro Luminescence) displays.

[0058] The control unit 90 includes one or more processors. In this disclosure, “processor” is a general-purpose processor or a dedicated processor specialized for a particular process, but is not limited to these. The control unit 90 includes, for example, a CPU (Central Processing Unit). The control unit 90 is communicatively connected to each component constituting the optical measuring device 1 and controls the operation of the entire optical measuring device 1. The control unit 90 measures the optical properties of the object to be measured S based on the light to be measured L2 received by the light receiving unit 30. The control unit 90 performs a calibration process using a standard member 41 based on the reference light L3 received by the light receiving unit 30. In addition to the measurement and calibration processes described above, the control unit 90 may perform various calculation processes, including other processes related to optical properties, and control processes that control the operation of each component constituting the optical measuring device 1.

[0059] According to the optical measuring device 1 of the above embodiment, it is possible to increase the amount of light of the reference light L3 in the reference measurement. The calibration unit 40 of the optical measuring device 1 transitions between a first state in the reference measurement and a second state in the measurement of the object S to be measured. The calibration unit 40 has a standard member 41 that propagates at least a portion of the irradiated light L1 as reference light L3 toward the light receiving unit 30 and an optical element 42 that focuses the irradiated light L1 onto the standard member 41.

[0060] As a result, the optical measuring device 1 can realize a probe structure that, when measuring the object S to be measured, irradiates the object S to be measured with irradiation light L1 through a thick optical window W, and collects and receives the light to be measured L2. In addition, in reference measurements, the optical measuring device 1 can insert the calibration unit 40 between the irradiation unit 10 and the light receiving unit 30 and the optical window W in conjunction with the measurement by the spectroscopic sensor 31, without removing the optical measuring device 1 as a measurement probe from the manufacturing line including piping and tanks, via a control device such as the control unit 90.

[0061] As described above, unlike conventional technology, the optical measuring device 1 can position the focal point of the irradiated light L1 on the object to be measured S during measurement, while positioning the focal point of the irradiated light L1 on the standard member 41 during reference measurement. Therefore, the optical measuring device 1 can receive light with sufficient light intensity in both measurement of the object to be measured S and reference measurement. The optical measuring device 1 can position the focal point of the irradiated light L1 on the object to be measured S and the standard member 41, respectively, even when the distance from the light source 11 to the object to be measured S and the distance from the light source 11 to the standard member 41 differ significantly, such as by 10 mm or more.

[0062] In the first state, the optical element 42 positions the focal point of the irradiated light L1 on the standard member 41 on the optical axis A of the light receiving unit 30. This allows the optical measuring device 1 to position the focal point of the irradiated light L1 on the optical axis A of the light receiving unit 30 not only when measuring the object under measurement S, but also when performing reference measurements. For example, when measuring the object under measurement S, the optical measuring device 1 positions the focal point of the irradiated light L1 in a region including the intersection of the optical axis A of the light receiving unit 30 and the object under measurement S. On the other hand, when performing reference measurements, the optical measuring device 1 positions the focal point of the irradiated light L1 in a region including the intersection of the optical axis A of the light receiving unit 30 and the standard member 41. As a result, the optical measuring device 1 can receive light with sufficient light intensity in either measurement.

[0063] In the first state, the optical axis of the optical element 42 coincides with the optical axis A of the light receiving unit 30. This allows the optical measuring device 1 to arrange the optical element 42 symmetrically with respect to the optical axis A. The optical measuring device 1 also allows the calibration unit 40, which includes the optical element 42, to be arranged symmetrically with respect to the optical axis A. Therefore, the optical measuring device 1 can improve the symmetry of the optical system, and as a result, it facilitates assembly work by workers and others involved in the optical system.

[0064] The irradiation unit 10 has a plurality of light sources 11, each emitting irradiation light L1. As a result, the light measuring device 1 can increase the amount of light L2 to be measured from the object to be measured S when measuring the object to be measured S, and can receive light with sufficient light intensity. Similarly, the light measuring device 1 can increase the amount of reference light L3 from the standard member 41 when performing a reference measurement, and can receive light with sufficient light intensity.

[0065] The multiple light sources 11 are arranged rotationally symmetrically with respect to the optical axis A of the light receiving unit 30. This allows the light measuring device 1 to arrange the multiple light sources 11 symmetrically with respect to the optical axis A. The light measuring device 1 allows the illumination unit 10, which includes the multiple light sources 11, to be arranged symmetrically with respect to the optical axis A. Therefore, the light measuring device 1 can improve the symmetry of the optical system, and as a result, the assembly work of the optical system by workers and others is facilitated.

[0066] The optical measuring device 1 further includes a housing 50 that integrally houses the irradiation unit 10 and the calibration unit 40 in a first state. This allows the optical measuring device 1 to position the calibration unit 40 between the irradiation unit 10 and the light receiving unit 30 and the optical window W inside the housing 50, and to complete the reference measurement inside the housing 50. Therefore, the optical measuring device 1 enables the reception of reference light L3 by the light receiving unit 30, including the spectroscopic sensor 31, within the housing 50 without removing the optical measuring device 1 as a measuring probe from the manufacturing line, including piping and tanks, during the reference measurement. The optical measuring device 1 can easily transition to the reference measurement while maintaining the setup used for measuring the object S under measurement. As a result, the convenience of the optical measuring device 1 is improved.

[0067] In the first embodiment described above, the optical element 42 is configured to position the focal point of the irradiated light L1 on the standard member 41 on the optical axis A of the light receiving unit 30 in the first state, but it is not limited to this. The optical element 42 does not have to position the focal point of the irradiated light L1 on the standard member 41 on the optical axis A of the light receiving unit 30 in the first state. That is, in the first state, the focal point of the irradiated light L1 on the standard member 41 and the region including the intersection of the optical axis A of the light receiving unit 30 and the standard member 41 may be offset from each other.

[0068] In the first embodiment described above, the optical axis of the optical element 42 is said to coincide with the optical axis A of the light-receiving unit 30 in the first state, but this is not limited to this. The optical axis of the optical element 42 does not have to coincide with the optical axis A of the light-receiving unit 30 in the first state.

[0069] In the first embodiment described above, the irradiation unit 10 was described as having a plurality of light sources 11, each emitting irradiation light L1, but it is not limited to this. For example, the irradiation unit 10 was described as having two light sources 11, but it is not limited to this. The irradiation unit 10 may have only one light source 11, or it may have three or more light sources 11.

[0070] In the first embodiment described above, the multiple light sources 11 were arranged rotationally symmetrically with respect to the optical axis A of the light receiving unit 30, but this is not limited to this configuration. The multiple light sources 11 may be arranged line-symmetrically or point-symmetrically with respect to the optical axis A of the light receiving unit 30. Conversely, the multiple light sources 11 may be arranged asymmetrically.

[0071] In the first embodiment described above, the optical measuring device 1 is further described as having a housing 50 that integrally houses the irradiation unit 10 and the calibration unit 40 in a first state, but it is not limited to this. The housing 50 of the optical measuring device 1 may also house the entire light receiving unit 30 in addition to the irradiation unit 10 and the calibration unit 40. Conversely, the optical measuring device 1 does not have to have a housing 50 that houses each component.

[0072] In the first embodiment described above, the optical measuring device 1 is said to have a light guide section 20 as a probe window attached to the housing 50, but it is not limited to this. The optical measuring device 1 does not have to have a light guide section 20. In this case, the housing 50 of the optical measuring device 1 may not be separated from the piping and tank etc. on which the optical window W is installed, but may be integrally configured with the piping and tank etc. with the optical window W as a probe window.

[0073] In the first embodiment described above, the optical measuring device 1 was described as measuring the optical properties of the object to be measured S using the diffuse reflectance method, but it is not limited to this. The optical measuring device 1 may also measure the optical properties of the object to be measured S using a method other than the diffuse reflectance method.

[0074] In the first embodiment described above, the optical properties included, but are not limited to, the wavelength dependence of the reflectance of light. The optical properties may include the reflectance of light at a specific wavelength, rather than including wavelength dependence, such as the reflectance spectrum. The optical properties may include any other properties relating to light absorption, transmission, and scattering, in place of, or in addition to, properties relating to light reflection. For example, the optical properties may include wavelength dependence of light absorptivity, transmittance, and scattering coefficients, or they may include light absorptivity, transmittance, and scattering coefficients at a specific wavelength.

[0075] In the first embodiment described above, the light under measurement L2 was explained to include reflected light such as diffuse reflected light propagating backward from the object under measurement S to which the irradiated light L1 was irradiated, but it is not limited to this. The light under measurement L2 may also include light absorbed by the object under measurement S, or it may include scattered light obtained by scattering the irradiated light L1 at the object under measurement S.

[0076] In the first embodiment described above, the reference light L3 was explained to include reflected light such as diffuse reflected light propagating backward from the standard member 41 irradiated with the irradiation light L1, but is not limited to this. The reference light L3 may also include light absorbed by the standard member 41, or it may include scattered light from the irradiation light L1 scattered by the standard member 41.

[0077] In the first embodiment described above, the irradiation unit 10 is said to have an optical element 12 that guides the irradiation light L1 emitted from the light source 11 toward the object to be measured S, but it is not limited to this. The irradiation unit 10 does not have to have an optical element 12.

[0078] In the first embodiment described above, the light-receiving unit 30 was described as having a spectral sensor 31, but it is not limited to this. The light-receiving unit 30 may have other photodetectors, including a photodetector such as a photodiode, instead of or in addition to the spectral sensor 31. The light-receiving unit 30 may also have a function to acquire information on the intensity of light, instead of or in addition to the spectral information of light.

[0079] In the first embodiment described above, the light-receiving unit 30 was described as having an optical element 32 that guides the light to be measured L2 from the object to be measured S or the reference light L3 from the standard member 41 toward the spectroscopic sensor 31, but it is not limited to this. The light-receiving unit 30 does not have to have an optical element 32.

[0080] In the first embodiment described above, the light-receiving unit 30 was described as having a light guide component 33 that guides the light to be measured L2 from the object to be measured S or the reference light L3 from the standard member 41, which has been focused by the optical element 32, to the spectroscopic sensor 31. However, it is not limited to this. The light-receiving unit 30 does not have to have a light guide component 33. The optical element 32 of the light-receiving unit 30 may directly focus the light to be measured L2 or the reference light L3 at the incident part of the spectroscopic sensor 31 instead of the light guide component 33.

[0081] (Second Embodiment) Figure 3 is a schematic diagram showing an example of the configuration of the optical measuring device 1 according to the second embodiment of this disclosure. Figure 3 is a schematic diagram corresponding to Figure 2, showing the configuration of the optical measuring device 1 during reference measurement. In Figure 3, the refraction of light in the lens and window shown as an example of the configuration of the optical measuring device 1 is simplified for the purpose of simple illustration in the drawing. In addition, in Figure 3, the storage unit 60, input unit 70, output unit 80, and control unit 90 shown in Figures 1 and 2 are omitted. An example of the configuration and function of the optical measuring device 1 according to the second embodiment will be mainly described with reference to Figure 3.

[0082] The optical measuring device 1 according to the second embodiment of this disclosure differs from the first embodiment in that the optical element 42 of the calibration unit 40 has a through hole 42a. Other configurations, functions, effects, and modifications are the same as in the first embodiment, and corresponding descriptions also apply to the optical measuring device 1 according to the second embodiment. In the following, components the same as in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. The differences from the first embodiment will be mainly described.

[0083] The optical element 42 of the calibration unit 40 may have a through hole 42a positioned to coincide with the optical axis A of the light receiving unit 30 in the first state. For example, the optical element 42 may have a through hole 42a in its central part. The diameter of the through hole 42a may be greater than or equal to the diameter of the reference light L3 when the reference light L3 from the standard member 41, which is received by the light receiving unit 30, passes through the optical element 42 in the first state. For example, the diameter of the through hole 42a may be greater than or equal to the diameter of the reference light L3 when the reference light L3 incident on the optical element 32 of the light receiving unit 30 passes through the optical element 42.

[0084] The through-hole 42a may have a shape that tapers in reverse from the standard member 41 side toward the light-receiving unit 30 side. The shape of the through-hole 42a may be a frustoconical shape, for example, as shown in Figure 3, where the diameter of the hole is smaller on the standard member 41 side and larger on the optical element 32 side of the light-receiving unit 30.

[0085] The optical measuring device 1 has a through hole 42a positioned to coincide with the optical axis A, which allows the reference light L3 from the standard member 41 to be propagated to the light receiving unit 30 while reducing the influence of optical effects from the optical element 42. Therefore, the optical measuring device 1 can reduce the difference between the optical system during measurement of the object S under measurement in the second state where the calibration unit 40 is not inserted into the optical system and the optical system during reference measurement, compared to the case of the first embodiment.

[0086] The optical measuring device 1 is able to propagate the reference light L3 from the standard member 41 to the light receiving unit 30 with further reduced influence from the optical effects of the optical element 42, because the diameter of the through-hole 42a is greater than or equal to the diameter of the reference light L3 when it passes through the optical element 42. Therefore, the optical measuring device 1 can further reduce the difference between the optical system during measurement of the object S under measurement in the second state where the calibration unit 40 is not inserted into the optical system, and the optical system during reference measurement.

[0087] The optical measuring device 1 has a through-hole 42a that tapers in reverse from the standard member 41 side towards the light-receiving unit 30 side. This allows the reference light L3, whose diameter gradually widens from the standard member 41 towards the light-receiving unit 30, to propagate to the light-receiving unit 30 while reducing the influence of optical effects from the optical element 42. Therefore, the optical measuring device 1 can reduce the difference between the optical system during measurement of the object S under measurement in the second state where the calibration unit 40 is not inserted into the optical system, and the optical system during reference measurement.

[0088] In the second embodiment described above, the diameter of the through-hole 42a was explained to be greater than or equal to the diameter of the reference light L3 when the reference light L3 from the standard member 41, which is received by the light-receiving unit 30 in the first state, passes through the optical element 42. However, it is not limited to this. The diameter of the through-hole 42a may be smaller than the diameter of the reference light L3 when the reference light L3 passes through the optical element 42.

[0089] In the second embodiment described above, the through-hole 42a was described as having a shape that tapers in reverse from the standard member 41 side toward the light-receiving part 30 side, but it is not limited to this. The through-hole 42a may have a shape other than a reverse taper. For example, the through-hole 42a may have a cylindrical shape with a uniform diameter.

[0090] (Third embodiment) Figure 4 is a schematic diagram showing an example of the configuration of the optical measuring device 1 according to the third embodiment of this disclosure. Figure 4 is a schematic diagram corresponding to Figure 3, showing the configuration of the optical measuring device 1 during reference measurement. In Figure 4, the refraction of light in the lens and window shown as an example of the configuration of the optical measuring device 1 is simplified for the purpose of simple illustration in the drawing. In addition, in Figure 4, the storage unit 60, input unit 70, output unit 80, and control unit 90 shown in Figures 1 and 2 are omitted. An example of the configuration and function of the optical measuring device 1 according to the third embodiment will be mainly described with reference to Figure 4.

[0091] The optical measuring device 1 according to the third embodiment of this disclosure differs from the second embodiment in that the calibration unit 40 further includes an optical element 43. Other configurations, functions, effects, and modifications are the same as in the second embodiment, and corresponding descriptions also apply to the optical measuring device 1 according to the third embodiment. In the following, components the same as in the second embodiment are denoted by the same reference numerals, and their descriptions are omitted. The differences from the second embodiment will be mainly described.

[0092] The calibration unit 40 may further include an optical element 43 that is positioned over the through-hole 42a of the optical element 42 and guides the reference light L3 from the standard member 41 to the light-receiving unit 30 in the first state. The optical element 43 corresponds to the "second optical element" in the claims. The optical element 43 may include elements such as a single lens, a combination of multiple lenses, a prism, and a mirror. The optical element 43 may be positioned at the end of the through-hole 42a closest to the standard member 41. In this case, the optical axis of the optical element 43 may coincide with the optical axis A of the light-receiving unit 30 in the first state.

[0093] The optical measuring device 1, by having an optical element 43 in the calibration unit 40, can guide the reference light L3 from the standard member 41 to the optical element 32 of the light receiving unit 30 via the optical element 43 located in the through hole 42a. Therefore, by appropriately setting the numerical aperture of the optical element 43, the optical measuring device 1 can also focus a larger amount of reference light L3 on the light guide component 33 of the light receiving unit 30 during reference measurement than in the first and second embodiments.

[0094] In the light measuring device 1, by aligning the optical axis of the optical element 43 with the optical axis A of the light receiving unit 30, it is possible to focus a reference light L3 with an even greater intensity of light than in the first and second embodiments onto the light guide component 33 of the light receiving unit 30 during reference measurement.

[0095] In the third embodiment described above, the optical element 43 of the calibration unit 40 is arranged in overlap with the through hole 42a, but this is not the only configuration. The optical element 43 of the calibration unit 40 may be arranged between the optical element 42 and the standard member 41, and in the first state, it may guide the reference light L3 from the standard member 41 to the light receiving unit 30.

[0096] As a result, the light measuring device 1 can guide the reference light L3 from the standard member 41 to the optical element 32 of the light receiving unit 30 via the optical element 43 located between the through hole 42a and the standard member 41. Therefore, by appropriately setting the numerical aperture of the optical element 43, the light measuring device 1 can also focus a larger amount of reference light L3 on the light guide component 33 of the light receiving unit 30 during reference measurement than in the first and second embodiments.

[0097] In the third embodiment described above, the optical axis of the optical element 43 is said to coincide with the optical axis A of the light-receiving unit 30 in the first state, but this is not limited to this. The optical axis of the optical element 43 does not have to coincide with the optical axis A of the light-receiving unit 30 in the first state.

[0098] (Fourth Embodiment) Figure 5 is a schematic diagram showing an example of the configuration of the optical measuring device 1 according to the fourth embodiment of this disclosure. Figure 5 is a schematic diagram corresponding to Figure 2, showing the configuration of the optical measuring device 1 during reference measurement. In Figure 5, the refraction of light in the lens and window shown as an example of the configuration of the optical measuring device 1 is simplified for the purpose of simple illustration in the drawing. In addition, in Figure 5, the storage unit 60, input unit 70, output unit 80, and control unit 90 shown in Figures 1 and 2 are omitted. An example of the configuration and function of the optical measuring device 1 according to the fourth embodiment will be mainly described with reference to Figure 5.

[0099] The optical measuring device 1 according to the fourth embodiment of this disclosure differs from the first embodiment in that the calibration unit 40 has a plurality of optical elements 42. Other configurations, functions, effects, and modifications are the same as in the first embodiment, and corresponding descriptions also apply to the optical measuring device 1 according to the fourth embodiment. In the following, components the same as in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. The differences from the first embodiment will be mainly described.

[0100] The calibration unit 40 may have a plurality of optical elements 42, each positioned for a plurality of light sources 11 in the first state. For example, the calibration unit 40 may have two optical elements 42, each positioned for two light sources 11. The calibration unit 40 may have a corresponding optical element 42 for each light source 11.

[0101] The optical measuring device 1 has a calibration unit 40 that has multiple optical elements 42, each positioned for a plurality of light sources 11, which makes it possible to propagate the reference light L3 from the standard member 41 in the space between the multiple optical elements 42. Therefore, the optical measuring device 1 can propagate the reference light L3 from the standard member 41 to the light receiving unit 30 while reducing the influence of optical effects from the optical elements 42, similar to the second embodiment. Thus, the optical measuring device 1 can make the difference between the optical system during measurement of the object S under measurement in the second state, when the calibration unit 40 is not inserted into the optical system, and the optical system during reference measurement smaller compared to the first embodiment.

[0102] It will be apparent to those skilled in the art that this disclosure can be implemented in other predetermined forms besides the embodiments described above without deviating from its spirit or essential features. Therefore, the prior description is illustrative and not limiting. The scope of the disclosure is defined not by the prior description but by the added claims. Any modifications within their equivalent scope are included therein.

[0103] For example, the shape, pattern, size, arrangement, orientation, type, and number of each component described above are not limited to those shown in the above description and drawings. The shape, pattern, size, arrangement, orientation, type, and number of each component may be configured arbitrarily as long as they can realize their function. Each component of the illustrated optical measuring device 1 is a functional concept. The specific form of each component is not limited to those shown.

[0104] For example, the optical element 43 of the calibration unit 40 described in the third embodiment may be similarly arranged in the light measuring device 1 according to the first and fourth embodiments. In this case, the optical element 43 of the calibration unit 40 may be arranged between the optical element 42 and the standard member 41, and in the first state, it may guide the reference light L3 from the standard member 41 to the light receiving unit 30.

[0105] Some embodiments of the present disclosure are described below. However, it should be noted that the embodiments of the present disclosure are not limited to these. [Note 1] An irradiation unit that irradiates the object to be measured with light, A light receiving unit that receives the light to be measured from the object to be measured based on the aforementioned irradiated light on the same side as the irradiating unit, A calibration unit used for reference measurement, comprising a standard member that propagates at least a portion of the irradiated light toward the light receiving unit as reference light, and a first optical element that focuses the irradiated light onto the standard member, Prepare, The calibration unit transitions between a first state in the reference measurement, where it is positioned in conjunction with the optical path of the irradiated light between the irradiation unit and the light receiving unit and the object to be measured, and a second state in the measurement of the object to be measured, where it is positioned away from the optical path. Light measuring device. [Note 2] The optical measuring device described in Appendix 1, The first optical element, in the first state, positions the point of collection of the irradiated light in the standard member on the optical axis of the light receiving section. Light measuring device. [Note 3] A light measuring device as described in Appendix 1 or 2, The optical axis of the first optical element coincides with the optical axis of the light receiving unit in the first state. Light measuring device. [Note 4] An optical measuring device described in any one of the appendices 1 to 3, The irradiation unit has a plurality of light sources, each of which emits the irradiation light. Light measuring device. [Note 5] The optical measuring device described in Appendix 4, The plurality of light sources are arranged rotationally symmetrically with respect to each other around the optical axis of the light receiving unit. Light measuring device. [Note 6] A light measuring device as described in Appendix 4 or 5, The calibration unit has a plurality of first optical elements, each of which is arranged for the plurality of light sources in the first state. Light measuring device. [Note 7] An optical measuring device described in any one of the appendices 1 to 6, The first optical element has a through hole positioned in the first state to coincide with the optical axis of the light receiving portion. Light measuring device. [Note 8] The optical measuring device described in Appendix 7, The diameter of the through-hole is greater than or equal to the diameter of the reference light when the reference light from the standard member, which is received by the light-receiving unit in the first state, passes through the first optical element. Light measuring device. [Note 9] The optical measuring device described in Appendix 7 or 8, The through-hole has a shape that tapers in reverse from the standard member side toward the light-receiving part side. Light measuring device. [Note 10] An optical measuring device as described in any one of the appendices 7 to 9, The calibration unit further includes a second optical element that is positioned in conjunction with the through-hole and guides the reference light from the standard member to the light-receiving unit in the first state. Light measuring device. [Note 11] An optical measuring device described in any one of the appendices 1 to 9, The calibration unit further comprises a second optical element positioned between the first optical element and the standard member, which in the first state guides the reference light from the standard member to the light receiving unit. Light measuring device. [Note 12] An optical measuring device as described in Appendix 10 or 11, The optical axis of the second optical element coincides with the optical axis of the light receiving unit in the first state. Light measuring device. [Note 13] A light measuring device described in any one of the appendices 1 to 12, The system further comprises a housing that integrally houses the irradiation unit and the calibration unit in the first state. Light measuring device. [Explanation of symbols]

[0106] 1. Optical measuring device 10 Irradiation area 11 Light source 12 Optical elements 20 Light guide section 30 Light receiving part 31 Spectroscopic Sensor 32 Optical Circumference 33 Light guide components 40. Calibration Department 41 Standard components 42 Optical elements (first optical element) 42a through hole 43 Optical element (second optical element) 50 cabinets 60 Storage section 70 Input section 80 Output section 90 Control Unit A optical axis L1 irradiation light L2 Measured light L3 reference light S The object to be measured W optical cell

Claims

1. An irradiation unit that irradiates the object to be measured with light, A light receiving unit that receives the light to be measured from the object to be measured based on the aforementioned irradiated light on the same side as the irradiating unit, A calibration unit used for reference measurement, comprising a standard member that propagates at least a portion of the irradiated light toward the light receiving unit as reference light, and a first optical element that focuses the irradiated light onto the standard member, Prepare, The calibration unit transitions between a first state in the reference measurement, where it is positioned in the optical path of the irradiated light between the irradiation unit and the light receiving unit and the object to be measured, and a second state in the measurement of the object to be measured, where it is positioned away from the optical path. Light measuring device.

2. The optical measuring device according to claim 1, The first optical element, in the first state, positions the light-collecting point of the irradiated light on the standard member on the optical axis of the light-receiving section. Light measuring device.

3. A light measuring device according to claim 1 or 2, In the first state, the optical axis of the first optical element coincides with the optical axis of the light receiving unit. Light measuring device.

4. A light measuring device according to claim 1 or 2, The irradiation unit has a plurality of light sources, each of which emits the irradiation light. Light measuring device.

5. The optical measuring device according to claim 4, The plurality of light sources are arranged rotationally symmetrically with respect to each other around the optical axis of the light receiving unit. Light measuring device.

6. The optical measuring device according to claim 4, The calibration unit has a plurality of first optical elements, each of which is arranged for the plurality of light sources in the first state. Light measuring device.

7. A light measuring device according to claim 1 or 2, The first optical element has a through hole positioned in the first state to coincide with the optical axis of the light receiving portion. Light measuring device.

8. The optical measuring device according to claim 7, The diameter of the through-hole is greater than or equal to the diameter of the reference light when the reference light from the standard member, which is received by the light-receiving unit in the first state, passes through the first optical element. Light measuring device.

9. The optical measuring device according to claim 7, The through-hole has a shape that tapers in reverse from the standard member side toward the light-receiving part side. Light measuring device.

10. The optical measuring device according to claim 7, The calibration unit further includes a second optical element that is positioned in conjunction with the through-hole and guides the reference light from the standard member to the light-receiving unit in the first state. Light measuring device.

11. A light measuring device according to claim 1 or 2, The calibration unit further includes a second optical element positioned between the first optical element and the standard member, which in the first state guides the reference light from the standard member to the light receiving unit. Light measuring device.

12. The optical measuring device according to claim 10, The optical axis of the second optical element coincides with the optical axis of the light receiving unit in the first state. Light measuring device.

13. A light measuring device according to claim 1 or 2, The system further comprises a housing that integrally houses the irradiation unit and the calibration unit in the first state. Light measuring device.

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