Spectroscopic measurement device

Abstract

This spectroscopic measurement device is provided with: a first light source that emits first irradiation light at a first half-value angle with a first optical axis as a center line; a second light source that emits second irradiation light at a second half-value angle with a second optical axis as a center line; and a detection unit that has a field of view with the third optical axis as the center line, and that disperses and detects the measurement light emitted from the object. The first light source and the second light source are disposed on a plane perpendicular to the third optical axis with respect to the detection unit such that the distance between the first optical axis and the third optical axis and the distance between the second optical axis and the third optical axis are equal to each other. The absolute value of the difference between the first half-value angle and the second half-value angle is 4 degrees or less.

Description

Technical Field

[0001] This invention relates to a spectrophotometer. Background Technology

[0002] A spectrophotometer is known to include: a first light source emitting illumination light having a first center wavelength; a second light source emitting illumination light having a second center wavelength different from the first center wavelength; and a detection unit for detecting the measurement light emitted from the object based on the illumination of the illumination light (see, for example, Patent Document 1). This spectrophotometer utilizes the property that the object being measured (e.g., fat contained in the human body) readily absorbs light of a specific wavelength to obtain a predetermined quantitative value (e.g., the amount of fat in the human body) in the object.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-070550 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In the aforementioned spectrophotometer, ideally, the profile (proportional shape) of the spectrophotometer's spectrum should remain unchanged in order to accurately obtain the specified quantitative value of the object. However, when the distance between the object and the spectrophotometer changes, the profile of the spectrophotometer's spectrum may change significantly in some cases, leading to a deterioration in measurement accuracy.

[0008] The purpose of this invention is to provide a spectrophotometer that can suppress the degradation of measurement accuracy even when the distance between the object and the spectrophotometer changes.

[0009] means for solving problems

[0010] One aspect of the spectrophotometer of the present invention is: [1] "A spectrophotometer comprising: a first light source that emits a first illumination light having a first center wavelength with a first optical axis as the center line and a first half-value angle; a second light source that emits a second illumination light having a second center wavelength different from the first center wavelength with a second optical axis as the center line and a second half-value angle; and a detection unit having a field of view with a third optical axis as the center line, for spectrophotometers emitted from an object in response to illumination by the first illumination light and the second illumination light, wherein the first light source and the second light source are arranged relative to the detection unit in such a way that the distance between the first optical axis and the third optical axis and the distance between the second optical axis and the third optical axis are equal to each other, and the absolute value of the difference between the first half-value angle and the second half-value angle is 4 degrees or less.

[0011] In the spectrophotometer described above [1], the first light source and the second light source are arranged relative to the detection unit on a plane perpendicular to the third optical axis, such that the distance between the first optical axis of the first light source and the third optical axis of the detection unit is equal to the distance between the second optical axis of the second light source and the third optical axis of the detection unit. The absolute value of the difference between the first half-value angle of the first irradiation light and the second half-value angle of the second irradiation light is 4 degrees or less. Therefore, even if the distance between the object and the spectrophotometer changes, the significant change in the ratio of the light intensity of the first irradiation light to the light intensity of the second irradiation light in the field of view of the detection unit with the third optical axis as the center line is suppressed. Therefore, even if the distance between the object and the spectrophotometer changes, the significant change in the profile of the spectrophotometer spectrum of the measurement light, for which it is ideally desired that its profile does not change, is suppressed. Therefore, according to the spectrophotometer described above [1], even if the distance between the object and the spectrophotometer changes, the degradation of measurement accuracy can be suppressed.

[0012] One aspect of the spectrophotometer of the present invention may also be: [2] "In the spectrophotometer described in [1] above, the detection unit includes: a lens that defines the field of view such that the angle of the field of view is -5 degrees or more and 5 degrees or less; a light guide that guides the measurement light that passes through the lens; and a spectrometer that splits and detects the measurement light guided by the light guide." According to the spectrophotometer described in [2], the measurement range can be kept approximately constant regardless of the distance between the object and the spectrophotometer.

[0013] One aspect of the spectrophotometer of the present invention may also be: [3] "In the spectrophotometer described in [1] or [2] above, the first light source is each of a plurality of first light sources, the second light source is each of a plurality of second light sources, and the plurality of first light sources and the plurality of second light sources are alternately arranged on a circumference centered on the intersection of the third optical axis and the plane." According to the spectrophotometer described in [3], the first irradiation light and the second irradiation light can be uniformly irradiated onto an object located on the third optical axis. As a result, the ratio of the intensity of the first irradiation light to the intensity of the second irradiation light in the object can remain constant even at positions deviating from the third optical axis. As a result, the degradation of the measurement accuracy of the specified quantitative value of the object can be further suppressed.

[0014] One aspect of the spectrophotometer of the present invention may also be: [4] "In any of the spectrophotometers described in [1] to [3] above, the first light source includes: a first light-emitting element that emits the first illumination light; a first reflector that reflects the first illumination light emitted from the first light-emitting element; and a first sealing member that seals the first light-emitting element and the first reflector; the second light source includes: a second light-emitting element that emits the second illumination light; a second reflector that reflects the second illumination light emitted from the second light-emitting element; and a second sealing member that seals the second light-emitting element and the second reflector." According to the spectrophotometer described in [4], the first light source and the second light source can be respectively arranged at desired positions relative to the detection unit.

[0015] One aspect of the spectrophotometer of the present invention may also be: [5] "In the spectrophotometer described in [4] above, the first light source further includes a first lens detachably mounted to the first sealing member, and the second light source further includes a second lens detachably mounted to the second sealing member. The first lens transmits the first irradiation light with the first optical axis as the center line and at the first half-value angle by transmitting the first irradiation light reflected by the first reflector and transmitted through the first sealing member. The second lens transmits the second irradiation light reflected by the second reflector and transmitted through the second sealing member by transmitting the second irradiation light with the second optical axis as the center line and at the second half-value angle." According to the spectrophotometer described in [5], by performing at least one of replacing the first lens relative to the first sealing member and replacing the second lens relative to the second sealing member, the first half-value angle and the second half-value angle can be easily adjusted to the desired half-value angles, respectively.

[0016] One aspect of the spectrophotometer of the present invention may also be: [6] "In any of the spectrophotometers described in [1] to [3] above, the first light source includes a first light-emitting element that emits the first illumination light, the second light source includes a second light-emitting element that emits the second illumination light, and the first light source and the second light source share: a reflector that reflects the first illumination light emitted from the first light-emitting element and the second illumination light emitted from the second light-emitting element; and a sealing member that seals the first light-emitting element, the second light-emitting element and the reflector." According to the spectrophotometer described in [6], it is easy to realize a structure in which the absolute value of the difference between the first half-value angle and the second half-value angle is less than 4 degrees.

[0017] The spectrophotometer of one aspect of the present invention may also be: [7] "In any of the spectrophotometers described in [1] to [6] above, the first center wavelength and the second center wavelength are contained in the range of 360 nm or more and 2500 nm or less." According to the spectrophotometer described in [7], the spectrophotometer spectrum required to obtain the specified quantitative value of the object to be measured can be appropriately obtained.

[0018] One aspect of the spectrophotometer of the present invention may also be: [8] "In any of the spectrophotometers described in [1] to [7] above, a calculation unit is further provided, which calculates a predetermined quantitative value of the object based on a detection signal output from the detection unit." According to the spectrophotometer described in [8], a predetermined quantitative value of the object can be appropriately obtained.

[0019] The spectrophotometer of one aspect of the present invention may also be: [9] "In the spectrophotometer described in any of [1] to [8] above, at least one of the first half-value angle and the second half-value angle is 20 degrees or more." According to the spectrophotometer described in [9], the absolute value of the difference between the first half-value angle and the second half-value angle becomes relatively small relative to each of the first half-value angle of the first irradiated light and the second half-value angle of the second irradiated light, and thus the influence of the difference between the first half-value angle and the second half-value angle on the measurement accuracy can be reduced more reliably.

[0020] Invention Effects

[0021] According to the present invention, a spectrophotometer can be provided that can suppress the degradation of measurement accuracy even when the distance between the object and the spectrophotometer changes. Attached Figure Description

[0022] Figure 1 This is a diagram illustrating an example of the use of a spectrophotometer according to one embodiment.

[0023] Figure 2 yes Figure 1 The cross-sectional view of the spectrophotometer shown.

[0024] Figure 3 It is along Figure 2 The cross-sectional view of the spectrophotometer for line III-III is shown.

[0025] Figure 4 yes Figure 2 The first and second light sources are shown in side views.

[0026] Figure 5 It is a diagram used to illustrate the half-value angle.

[0027] Figure 6 It is shown Figure 1 The diagram shows the positional relationship between the illumination range of the first illumination light, the illumination range of the second illumination light, and the field of view of the detection unit in the spectrophotometer.

[0028] Figure 7 This is a diagram showing the positional relationship between the illumination range of the first illumination light, the illumination range of the second illumination light, and the field of view of the detection unit in the spectrophotometer of the comparative example.

[0029] Figure 8 It is shown Figure 1 The diagram shows the spectroscopic spectrum of the measurement light in the spectroscopic measuring apparatus shown and the spectroscopic spectrum of the measurement light in the comparative example spectroscopic measuring apparatus.

[0030] Figure 9 This is a side view of the first and second light sources in the modified example.

[0031] Figure 10 This is a side view of the first and second light sources in the modified example.

[0032] Figure 11 This is a diagram showing an example of the use of a modified spectrophotometer. Detailed Implementation

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same or equivalent elements, and repeated descriptions are omitted.

[0034] [Structure of the Spectrophotometer]

[0035] like Figure 1 As shown, the spectrophotometer 1 irradiates an object S with two types of illumination light, L11 and L12. By dispersing and detecting the measurement light L2 emitted from the object S based on the illumination of the two types of illumination light L11 and L12, a predetermined quantitative value in the object S is calculated. The spectrophotometer 1 utilizes the property that the object readily absorbs light of a specific wavelength to obtain the predetermined quantitative value in the object S. Figure 1 In the example shown, the spectrophotometer 1 is positioned above the conveyor belt C to obtain a specified quantitative value (e.g., the sugar content, water content, etc. of the fruit) for the object S (e.g., fruit) transported by the conveyor belt C.

[0036] like Figure 2 and Figure 3 As shown, the spectrophotometer 1 includes a frame 2, a support 3, multiple first light sources 4, multiple second light sources 5, a detection unit 6, and a calculation unit 7.

[0037] The frame 2 houses the support portion 3, multiple first light sources 4, multiple second light sources 5, the detection portion 6, and the calculation portion 7. The frame 2 includes a cylindrical main body portion 21 and a plate-shaped light-transmitting portion 22. The main body portion 21 has a center line parallel to direction A. With the thickness direction of the light-transmitting portion 22 aligned with direction A, the light-transmitting portion 22 closes one end of the main body portion 21.

[0038] The support portion 3 includes a support structure 31, a circuit board 32, and a retaining member 33. The support structure 31 is fixed to the main body 21 within the main body 21. With the thickness direction of the circuit board 32 aligned with direction A, the circuit board 32 is positioned relative to the support structure 31 on one side of direction A. The circuit board 32 has an opening 32a that opens on one side and the other side of direction A. The retaining member 33 is positioned relative to the circuit board 32 on one side of direction A. The retaining member 33 is fixed to the circuit board 32 by bolts 34. The retaining member 33 has multiple through holes 33a and one through hole 33b. Each through hole 33a and 33b passes through the retaining member 33 along direction A.

[0039] Multiple first light sources 4 and multiple second light sources 5 are mounted on the mounting surface 32b of the circuit board 32, located within multiple through holes 33a of the holding member 33. The mounting surface 32b is one of a pair of main surfaces of the circuit board 32 located on the side of direction A. Each first light source 4 has a first optical axis A1 parallel to direction A and emits a first illumination light L11 on one side of direction A. Each second light source 5 has a second optical axis A2 parallel to direction A and emits a second illumination light L12 on one side of direction A. The first illumination light L11 is light having a first center wavelength. The second illumination light L12 is light having a second center wavelength different from the first center wavelength.

[0040] The detection unit 6 is fixed to the support unit 3 in a state where it is located within the opening 32a of the circuit board 32 and the through hole 33b of the holding member 33. The detection unit 6 has a field of view V centered on a third optical axis A3 parallel to direction A, and disperses and detects the measurement light L2. The measurement light L2 is light emitted from the object S in response to the illumination of the first illumination light L11 and the second illumination light L12.

[0041] The detection unit 6 includes a lens 61, a light guide 62, and a beam splitter 63. The lens 61 is disposed on one side of the third optical axis A3 relative to the light guide 62 in direction A. The beam splitter 63 is disposed on the other side of the third optical axis A3 relative to the light guide 62 in direction A.

[0042] Lens 61 is fixed to the inner surface 22a of light-transmitting portion 22 while located within the through hole 33b of retaining member 33. Lens 61 defines a field of view V such that the angle of the field of view V is between -5 degrees and 5 degrees. In this embodiment, the angle of the field of view V is 0 degrees. In this case, the range of the field of view V is, for example, a cylindrical range centered on the third optical axis A3.

[0043] A field of view V with an angle of N degrees (N being a positive value) is a frustum-shaped field of view that increases in range with distance from lens 61, meaning that the taper angle of this frustum is N degrees. A field of view V with an angle of 0 degrees means that the range of this field of view remains constant even with distance from lens 61. A field of view V with an angle of -N degrees is a frustum-shaped field of view that narrows in range with distance from lens 61, meaning that the taper angle of this frustum is N degrees.

[0044] The light guide section 62 guides the measurement light L2, which passes through the lens 61, from one side of direction A to the other. The light guide section 62 is a cylindrical component centered on the third optical axis A3. The light guide section 62 is formed of metal (e.g., aluminum). The light guide section 62 extends to both sides of the circuit board 32 via the opening 32a. The light guide section 62 is fixed to the holding member 33 with one side of its portion disposed inside the through hole 33b. The light incident opening 62a of the light guide section 62 is located on one side relative to the circuit board 32, and the light exit opening 62b of the light guide section 62 is located on the other side relative to the circuit board 32. The inner surface 62c of the light guide section 62 is a light reflecting surface.

[0045] Beam splitter 63 splits and detects the measurement light L2 guided by light guide section 62. Beam splitter 63 includes: a frame having a light incident section 63a into which the measurement light L2 is incident; a diffraction grating that splits the incident measurement light L2 within the frame; and a light detection element that detects the split measurement light L2 within the frame. The frame of beam splitter 63 is fixed to support structure 31.

[0046] The arithmetic unit 7 is fixed to the support structure 31. Each first light source 4 and each second light source 5 are electrically connected to the arithmetic unit 7 via a circuit board 32. The light detection element of the beam splitter 63 is electrically connected to the arithmetic unit 7 via wiring 8. The arithmetic unit 7 is composed, for example, of electronic components including integrated circuits such as FPGAs (field-programmable gate arrays) and non-volatile memories such as EEPROMs (electrically erasable programmable read-only memory).

[0047] The calculation unit 7 calculates a predetermined quantitative value in the object S based on the detection signal output from the detection unit 6. Specifically, the calculation unit 7 performs spectroscopic measurement on the object S conveyed by the conveyor belt C to the bottom of the spectroscopic measurement device 1. Based on the detection signal output from the detection unit 6, the calculation unit 7 generates first data representing the spectroscopic spectrum of the measurement light L2. Based on the first data, the calculation unit 7 generates second data representing the second differential spectrum after second differentiation of the spectroscopic spectrum of the measurement light L2. Based on the second data, the calculation unit 7 calculates the predetermined quantitative value in the object S. In this embodiment, the calculation unit 7 also functions as a control unit for controlling the plurality of first light sources 4, the plurality of second light sources 5, and the detection unit 6. As the control unit, the calculation unit 7 simultaneously emits the first illumination light L11 and the second illumination light L12 from the plurality of first light sources 4 and the plurality of second light sources 5, while the detection unit 6 (specifically, the light detection element of the spectrometer 63) detects the measurement light L2.

[0048] [The positions of the first and second light sources relative to the detection unit]

[0049] Multiple first light sources 4 and multiple second light sources 5 are arranged relative to the detection unit 6 on a plane H perpendicular to the third optical axis A3, such that the distances between each first optical axis A1 and the third optical axis A3, and the distances between each second optical axis A2 and the third optical axis A3, are equal. In this embodiment, plane H is the surface including the mounting surface 32b of the circuit board 32. The multiple first light sources 4 and multiple second light sources 5 are alternately arranged on a circumference R centered on the intersection point C1 of the third optical axis A3 and plane H. In this embodiment, the multiple first light sources 4 and multiple second light sources 5 are arranged at equal angular intervals centered on the intersection point C1. That is, the multiple first light sources 4 and multiple second light sources 5 are arranged in a rotationally symmetrical manner centered on the intersection point C1. As an example, the multiple first light sources 4 and multiple second light sources 5 are arranged in a point-symmetrical (double-symmetric) manner centered on the intersection point C1.

[0050] [Structure of the first and second light sources]

[0051] like Figure 4As shown in (a), the first light source 4 is a first LED 40. In this embodiment, the first LED 40 is a projectile-type LED (light emitting diode). The first LED 40 includes a first light-emitting element 41, a first reflector 42, and a first sealing member 43. The first light-emitting element 41 emits a first illumination light L11. The first reflector 42 has a portion on the other side of direction A ( Figure 4 (a) shows the lower side of the reflective surface 42a, which is opposite to the first light-emitting element 41. The reflective surface 42a reflects the first illumination light L11 emitted from the first light-emitting element 41 to one side in direction A. Figure 4 (a) is the upper side). The first sealing member 43 seals the first light-emitting element 41 and the first reflector 42. The first illumination light L11 is reflected by the first reflector 42 and passes through the first sealing member 43, and is emitted from the first light source 4 with the first optical axis A1 as the center line and with the first half-value angle θ1.

[0052] like Figure 4 As shown in (b), the second light source 5 is a second LED 50. In this embodiment, the second LED 50 is a projectile-type LED. The second LED 50 includes a second light-emitting element 51, a second reflector 52, and a second sealing member 53. The second light-emitting element 51 emits a second illumination light L12. The second reflector 52 has a reflective surface 52a opposite to the second light-emitting element 51 on the other side of direction A. The reflective surface 52a reflects the second illumination light L12 emitted from the second light-emitting element 51 to one side of direction A. The second sealing member 53 seals the second light-emitting element 51 and the second reflector 52. The second illumination light L12, reflected by the second reflector 52 and transmitted through the second sealing member 53, is emitted from the second light source 5 with the second optical axis A2 as its centerline and with a second half-value angle θ2.

[0053] At least one of the first half-value angle θ1 and the second half-value angle θ2 is 20 degrees or more. The absolute value of the difference between the first half-value angle θ1 and the second half-value angle θ2 is less than 4 degrees. Here, "half-value angle θ" refers to... Figure 5 As shown, when the angle α is centered on the optical axis (0 degrees) and the intensity of the irradiated light is half of the intensity of the irradiated light on the optical axis, the value is represented by 2α.

[0054] The first and second center wavelengths are contained within the range of 360 nm to 2500 nm. The first and second center wavelengths are determined based on the absorption wavelength of the object being measured. Specifically, the first and second center wavelengths are determined to be values ​​near the absorption wavelength of the object being measured. As an example, the absorption wavelength of fat is 930 nm, that of water is 956 nm, and that of chlorophyll is 670 nm. Furthermore, the first and second center wavelengths can be contained within the visible light region of 360 nm to 830 nm, or within the near-infrared region of 780 nm to 2500 nm.

[0055] [Changes in the spectroscopic spectrum of the measuring light caused by the distance between the object and the spectrometer]

[0056] Reference Figure 6 , Figure 7 and Figure 8 This explains the change in the profile of the spectroscopic spectrum of the measuring light L2 caused by the distance between the object S and the spectroscopic measuring device 1. Figure 6 It is shown Figure 1 The diagram shows the positional relationship between the illumination range of the first illumination light L11, the illumination range of the second illumination light L12, and the field of view V of the detection unit 6 in the spectrophotometer 1. Figure 7 This is a diagram showing the positional relationship between the illumination range of the first illumination light L11, the illumination range of the third illumination light L13, and the field of view V of the detection unit 6 in the spectrophotometer 101 of the comparative example. Figure 8 (a) shows in Figure 6 The spectroscopic spectra G21, G22, and G23 of the measuring light L21, L22, and L23 emitted from the object S at positions P1, P2, and P3. Figure 8 (b) shows in Figure 7 The spectroscopic spectra G121, G122, and G123 of the measuring light L121, L122, and L123 emitted from the object S at positions P1, P2, and P3. Additionally, in Figure 6 In this design, the configuration of the first light source 4, the second light source 5, and the detection unit 6 is simplified, with the detection unit 6 positioned at the midpoint between the first light source 4 and the second light source 5. Similarly, in Figure 7 In the middle, the detection unit 6 is positioned at the midpoint between a first light source 4 and a third light source 500.

[0057] like Figure 6 As shown, in the spectrophotometer 1 of the embodiment, regardless of which of the three positions P1, P2, and P3 the object S is positioned, the ratio of the light intensity of the first illumination light L11 to the light intensity of the second illumination light L12 in the field of view V remains approximately constant. Therefore, as Figure 8As shown in (a), in each of the spectroscopic spectra G21, G22, and G23 of the measurement light L2, the ratio of the intensity at the second central wavelength λ2 to the intensity at the first central wavelength λ1 is approximately constant. That is, the profile of the spectroscopic spectrum of the measurement light L2 does not change significantly. As a result, the waveforms of the second differential spectra of the three spectroscopic spectra G21, G22, and G23 are approximately constant. Consequently, the quantitative value calculated in the calculation unit 7 remains constant regardless of which of the three positions P1, P2, and P3 the object S is positioned at.

[0058] like Figure 7 As shown, the comparative example spectrophotometer 101 includes a third light source 500 instead of the second light source 5. The third light source 500 has the same structure as the second light source 5, except that it has a third half-value angle θ3 that is different from the second half-value angle θ2 of the second light source 5. The third half-value angle θ3 is greater than the first half-value angle θ1. The absolute value of the difference between the first half-value angle θ1 and the third half-value angle θ3 exceeds 4 degrees, for example, 30 degrees. In the comparative example, as... Figure 7 As shown, the further the object S moves from position P1 to positions P2 and P3 and away from the detection unit 6, the more significantly the ratio of the light intensity of the first illumination light L11 to the light intensity of the third illumination light L13 changes in the field of view V. Therefore, as Figure 8 As shown in (b), in each spectroscopic spectrum G121, G122, and G123 of the measuring light L2, the ratio of the intensity at the second central wavelength λ2 to the intensity at the first central wavelength λ1 changes significantly. That is, the profile of the spectroscopic spectrum of the measuring light L2 changes significantly. As a result, the waveforms of the second differential spectra of the three spectroscopic spectra G121, G122, and G123 will be different from each other. Consequently, the quantitative value calculated in the calculation unit 7 will change depending on which of the three positions P1, P2, and P3 the object S is positioned at.

[0059] [Functions and Effects]

[0060] In the spectrophotometer 1, the first light source 4 and the second light source 5 are arranged relative to the detection unit 6 on a plane H perpendicular to the third optical axis A3, such that the distance between the first optical axis A1 of the first light source 4 and the third optical axis A3 of the detection unit 6 is equal to the distance between the second optical axis A2 of the second light source 5 and the third optical axis A3 of the detection unit 6. The absolute value of the difference between the first half-value angle θ1 of the first illumination light L11 and the second half-value angle θ2 of the second illumination light L12 is 4 degrees or less. Therefore, even if the distance between the object S and the spectrophotometer 1 changes, a significant change in the ratio of the light intensity of the first illumination light L11 to the light intensity of the second illumination light L12 in the field of view V of the detection unit 6 centered on the third optical axis A3 is suppressed. Therefore, even if the distance between the object S and the spectrophotometer 1 changes, a significant change in the profile of the spectrophotometer spectrum of the measurement light L2, whose profile is ideally expected to remain unchanged, is suppressed. Thus, even if the distance between the object S and the spectrophotometer 1 changes, degradation of measurement accuracy can be suppressed.

[0061] In the spectrophotometer 1, the lens 61 defines the field of view V of the detection unit 6 such that the angle of the field of view V is greater than -5 degrees and less than 5 degrees. As a result, the measurement range can be kept approximately constant regardless of the distance between the object S and the spectrophotometer 1.

[0062] In the spectrophotometer 1, multiple first light sources 4 and multiple second light sources 5 are alternately arranged on a circle R centered at the intersection C1 of the third optical axis A3 and the plane H. Therefore, the first illumination light L11 and the second illumination light L12 can be uniformly irradiated onto the object S located on the third optical axis A3. Consequently, the ratio of the intensity of the first illumination light L11 to the intensity of the second illumination light L12 in the object S remains constant even at positions deviating from the third optical axis A3. As a result, the measurement accuracy of the predetermined quantitative value of the object S can be further suppressed.

[0063] In the spectrophotometer 1, a plurality of first light sources 4 and a plurality of second light sources 5 are arranged in a rotationally symmetrical manner with respect to the intersection point C1 of the third optical axis A3 and the plane H. For example, the plurality of first light sources 4 and a plurality of second light sources 5 are arranged in a point-symmetrical manner with respect to the intersection point C1 of the third optical axis A3 and the plane H. Thus, even when the spectrophotometer 1 rotates around the third optical axis A3, the object S located on the third optical axis A3 can be uniformly irradiated with the first irradiation light L11 and the second irradiation light L12.

[0064] In the spectrophotometer 1, a first sealing member 43 seals the first light-emitting element 41 and the first reflector 42, and a second sealing member 53 seals the second light-emitting element 51 and the second reflector 52. This allows the first light source 4 and the second light source 5 to be positioned at desired locations relative to the detection unit 6.

[0065] In the spectrophotometer 1, the first center wavelength and the second center wavelength are contained in the range of 360 nm or more and 2500 nm or less. Therefore, the spectrophotometer spectrum required to appropriately obtain the specified quantitative value of the measured object S can be obtained.

[0066] In the spectrophotometer 1, the arithmetic unit 7 calculates a predetermined quantitative value of the object S based on the detection signal output from the detection unit 6. Thus, the predetermined quantitative value of the object S can be appropriately obtained.

[0067] In the spectrophotometer 1, at least one of the first half-value angle θ1 and the second half-value angle θ2 is 20 degrees or more. Therefore, relative to the first half-value angle θ1 of the first illumination light L11 and the second half-value angle θ2 of the second illumination light L12, the absolute value of the difference between the first half-value angle θ1 and the second half-value angle θ2 becomes relatively small, thus more reliably mitigating the impact of the difference between the first half-value angle θ1 and the second half-value angle θ2 on measurement accuracy.

[0068] [Variation Example]

[0069] The present invention is not limited to the embodiments described above. In the spectrophotometer 1 of the first modified example, as... Figure 9 As shown in (a) and (b), the first light source 4 may further include a first lens 46 detachably mounted relative to the first sealing member 43. The second light source 5 may further include a second lens 56 detachably mounted relative to the second sealing member 53. The first lens 46 transmits the first illumination light L11, which is reflected by the first reflector 42 and passes through the first sealing member 43, and emits the first illumination light L11 with the first optical axis A1 as the center line and at a first half-value angle θ1. The second lens 56 transmits the second illumination light L12, which is reflected by the second reflector 52 and passes through the second sealing member 53, and emits the second illumination light L12 with the second optical axis A2 as the center line and at a second half-value angle θ2. In the spectrophotometer 1 of the first modified example, by performing at least one of replacing the first lens 46 relative to the first sealing member 43 and replacing the second lens 56 relative to the second sealing member 53, the first half-value angle θ1 and the second half-value angle θ2 can be easily adjusted to the desired half-value angles, respectively.

[0070] In the second modified example of the spectrophotometer 1, the first light source 4 includes a first reflector 42 and a first sealing member 43, and the second light source 5 includes a second reflector 52 and a second sealing member 53, but is not limited thereto. For example, as... Figure 10 As shown, the first light source 4 and the second light source 5 can also share the reflector 142 and the sealing member 143. The sealing member 143 seals the first light-emitting element 41, the second light-emitting element 51, and the reflector 142. The reflector 142 has a side facing away from the first light-emitting element 41 in direction A. Figure 10The reflective surface 142a (lower side) is opposite to the first light-emitting element 41 and the second light-emitting element 51. The reflective plate 142 faces direction A. Figure 10 The first illumination light L11 emitted from the first light-emitting element 41 and the second illumination light L12 emitted from the second light-emitting element 51 are reflected from the upper side. In the spectrophotometer 1 of the second modified example, it is possible to easily achieve a structure in which the absolute value of the difference between the first half-value angle θ1 and the second half-value angle θ2 is less than 4 degrees.

[0071] In the above embodiments and variations, plane H is a plane that includes the mounting surface 32b of the circuit board 32, but it is not limited to this. This plane can be any plane that is perpendicular to the third optical axis A3. For example, this plane can also be a plane that includes a surface other than the mounting surface 32b of the circuit board 32, or it can be a plane that does not include any surface.

[0072] In the above embodiments and variations, the detection unit 6 only needs to be able to split and detect the measurement light L2. For example, the detection unit 6 only needs to have at least a beam splitter 63. As an example, the detection unit 6 may also not have a lens 61. In this case, the field of view V may also be defined as an angle greater than -5 degrees or less than 5 degrees. Furthermore, the detection unit 6 may also be other optical sensors capable of splitting and detecting the measurement light L2.

[0073] In the above embodiments and variations, although it is described that multiple first light sources 4 and multiple second light sources 5 are alternately arranged on a circumference R centered at the intersection C1 of the plane H perpendicular to the third optical axis A3 and the third optical axis A3, this is not a limitation. The multiple first light sources 4 and multiple second light sources 5 can be arranged relative to the detection unit 6 on the plane H perpendicular to the third optical axis A3, such that the distance between the first optical axis A1 of the first light source 4 and the third optical axis A3 of the detection unit 6, and the distance between the second optical axis A2 of the second light source 5 and the third optical axis A3 of the detection unit 6, are equal. For example, the multiple first light sources 4 can be arranged adjacent to each other on the circumference R, and the multiple second light sources 5 can also be arranged adjacent to each other on the circumference R.

[0074] In the above embodiments and variations, the first light source 4 has a first LED 40 and the second light source 5 has a second LED 50, but it is not limited thereto. The first light source 4 and the second light source 5 may also have light-emitting elements other than LEDs.

[0075] In the above embodiments and various modifications, although it is described that multiple first light sources 4 and multiple second light sources 5 are provided, it is sufficient to provide at least one first light source 4 and at least one second light source 5.

[0076] In the above embodiments and variations, the first center wavelength and the second center wavelength are included in the range of 360 nm or more and 2500 nm or less, but are not limited thereto. At least one of the first center wavelength and the second center wavelength may also be less than 360 nm or greater than 2500 nm.

[0077] In the above embodiments and variations, the spectrophotometer 1 may not include the arithmetic unit 7. For example, a predetermined quantitative value in the object S may be calculated based on a detection signal output from an arithmetic device located outside the spectrophotometer 1 to the detection unit 6. An example of an arithmetic device is a computer device such as a personal computer, smartphone, or tablet computer.

[0078] In the above embodiments and variations, at least one of the first half-value angle θ1 and the second half-value angle θ2 is 20 degrees or more, but is not limited thereto. For example, both the first half-value angle θ1 and the second half-value angle θ2 may be less than 20 degrees.

[0079] In the above embodiments and variations, the spectrophotometer 1 is positioned above the conveyor belt C, and measurement is performed when the object S is transported by the conveyor belt C to a position below the spectrophotometer 1, but this is not a limitation. For example, the user U can manually move the spectrophotometer 1 above the object S, and the measurement can be performed when the user U presses a switch. Furthermore, for example... Figure 11 As shown, the spectrophotometer 1 can also be located at the lower part of the drone D. In this case, when the drone D is brought above the object S by the user U's operation, the spectrophotometer 1 automatically performs the measurement.

[0080] Explanation of reference numerals in the attached figures

[0081] 1…Spectrophotometer, 4…First light source, 5…Second light source, 6…Detection unit, 7…Calculation unit, 41…First light-emitting element, 42…First reflector, 43…First sealing member, 46…First lens, 51…Second light-emitting element, 52…Second reflector, 53…Second sealing member, 56…Second lens, 61…Lens, 62…Light guide, 63…Spectrometer, 142…Reflector, 143…Sealing member, A1…First optical axis, A2…Second optical axis, A3…Third optical axis, C1…Intersection point, L11…First illumination light, L12…Second illumination light, L2, L21, L22, L23…Measuring light, H…Plane, R…Circumference, S…Object, V…Field of view, θ1…First half-value angle, θ2…Second half-value angle, λ1…First center wavelength, λ2…Second center wavelength.

Claims

1. A spectrophotometer, wherein, have: The first light source emits first illumination light with a first center wavelength about a first optical axis and at a first half-value angle. The second light source emits second illumination light with a second center wavelength that is different from the first center wavelength, with the second optical axis as the center line and at a second half-value angle; and The detection unit has a field of view centered on a third optical axis, and it disperses and detects the measurement light emitted from the object in response to the illumination of the first and second illumination lights. The first light source and the second light source are arranged relative to the detection unit on a plane perpendicular to the third optical axis, such that the distances between the first optical axis and the third optical axis and the distances between the second optical axis and the third optical axis are equal. The absolute value of the difference between the first half-value angle and the second half-value angle is less than 4 degrees.

2. The spectrophotometer as described in claim 1, wherein, The detection unit includes: a lens that defines the field of view such that the angle of the field of view is greater than or equal to -5 degrees and less than 5 degrees; a light guide that guides the measurement light transmitted through the lens; and a beam splitter that splits and detects the measurement light guided by the light guide.

3. The spectrophotometer as described in claim 1 or 2, wherein, The first light source is each of a plurality of first light sources. The second light source is each of a plurality of second light sources. The plurality of first light sources and the plurality of second light sources are alternately arranged on a circumference centered on the intersection of the third optical axis and the plane.

4. The spectrophotometer according to any one of claims 1 to 3, wherein, The first light source includes: a first light-emitting element that emits the first illumination light; a first reflector that reflects the first illumination light emitted from the first light-emitting element; and a first sealing member that seals the first light-emitting element and the first reflector. The second light source includes: a second light-emitting element that emits the second illumination light; a second reflector that reflects the second illumination light emitted from the second light-emitting element; and a second sealing member that seals the second light-emitting element and the second reflector.

5. The spectrophotometer as described in claim 4, wherein, The first light source also includes a first lens that is detachable from the first sealing member. The second light source also includes a second lens that is detachable from the second sealing member. The first lens transmits the first illumination light, which is reflected by the first reflector and passes through the first sealing member, with the first optical axis as the center line and at the first half-value angle. The second lens transmits the second illumination light, which is reflected by the second reflector and passes through the second sealing member, with the second optical axis as the center line and at the second half-value angle.

6. The spectrophotometer as described in any one of claims 1 to 3, wherein, The first light source includes a first light-emitting element that emits the first illumination light. The second light source includes a second light-emitting element that emits the second illumination light. The first light source and the second light source share: a reflector that reflects the first illumination light emitted from the first light-emitting element and the second illumination light emitted from the second light-emitting element; and a sealing member that seals the first light-emitting element, the second light-emitting element and the reflector.

7. The spectrophotometer according to any one of claims 1 to 6, wherein, The first center wavelength and the second center wavelength are contained in the range of 360 nm or more and 2500 nm or less.

8. The spectrophotometer according to any one of claims 1 to 7, wherein, It also includes a calculation unit that calculates a predetermined quantitative value of the object based on the detection signal output from the detection unit.

9. The spectrophotometer according to any one of claims 1 to 8, wherein, At least one of the first half-value angle and the second half-value angle is 20 degrees or more.

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