JPH10281871A - Light absorption characteristic measurement unit and light absorption characteristic measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify an optical system and to handle it easily. SOLUTION: A control part 4 selects one of light-emitting diodes 5-1 to 5-n successively based on an instruction from a computer 2 for control and outputs driving control data DDRV for driving, each of the light-emitting diodes 5-1 to 5-n injects measurement beams L1-Ln with different emission wavelengths based on the driving control data DDRV, and a photo diode 6 receives the measurement beams L1-Ln through a sample to be measured and outputs an original detection signal SO, thus simplifying an optical system, facilitating handling, enabling a signal to be exchanged at a low amplification rate in a rear-stage amplification system, and reducing the influence of a noise or a temperature drift. In addition, a plurality of light-emitting diodes 5-1 to 5-n with different emission wavelengths are driven successively, thus grasping a spectrum constituent quantitatively. The light-emitting diodes 5-1 to 5-n emit almost no infrared rays, can prevent a sample to be measured from being dried, and can measure a sample that should not be dried accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring light absorption characteristics and a method for measuring light absorption characteristics, and more particularly to measuring the light absorption characteristics inherent to a substance to quantify the components of the substance or to grasp the progress of a chemical reaction. TECHNICAL FIELD The present invention relates to a light absorption characteristic measurement unit and a light absorption characteristic measurement method used for the purpose.

[0002]

2. Description of the Related Art Absorbance or reflection absorbance of a substance at a specific wavelength, including the visible part, the near ultraviolet part and the near infrared part, is measured photoelectrically to indicate that the absorption of light by a solution or a solid matrix depends on the concentration. As a method for measuring the solution concentration according to Beer's law, absorption spectroscopy such as absorption spectroscopy is known.

[0003] The use of absorption spectroscopy is diverse, and for example, the following uses are used. (1) Compare the differences in leaf color at different locations where plants are collected. More specifically, it is a test of rice growth status. (2) When the concentration in the aqueous solution of a chemical substance is subjected to neutralization titration, it is confirmed by a unique color reaction using a coloring agent. More specifically, it is a neutralization assay.

(3) A substance that produces a dye that exhibits an absorption phenomenon in a specific wavelength range with respect to a specific chemical component, or
The concentration of the specific substance in the sample is assayed from the absorbance value when the sample is penetrated into a film coated with a substance whose absorption wavelength characteristic changes. More specifically, it is a dry multi-layer film for blood analysis, river water quality inspection, and the like.

(4) Colorimetric Inspection by Transmission or Reflection First Conventional Example FIG. 8 shows a schematic configuration diagram of an absorbance measuring device according to a first conventional example. The absorbance measuring device 100 includes a light source 101 that emits the original measurement light L ′, and an original measurement light L ′ that is emitted from the light source 101.
And a mirror 102 for reflecting and guiding the original measurement light L ′
Half mirror 10 that reflects a part of the light and transmits another part
3 and the original measurement light L ′ incident from the half mirror 103 side
Lens 104 for condensing light, a slit 105 for passing a part of the original measurement light L ′, a collimator mirror 106 for converting the original measurement light L ′ passing through the slit 105 into parallel light,
The original measurement light L ′ is incident, and a diffraction grating (grating) 107 that generates the measurement light LS as a spectrum due to mutual interference of the diffracted light of the original measurement light L ′ is generated by the diffraction grating 107. Reflected, slit 105, lens 104 and half mirror 1
A lens 108 for condensing the measurement light LS transmitted through
A beam splitter 109 that divides the measurement light LS into two equivalent measurement lights LS1 and LS2, a mirror 110 that reflects the measurement light LS1 and enters the measurement target sample SMPMEAS, and a measurement light LS2 that reflects the measurement light LS2 to the measurement reference sample SMPREF. The mirror 111 to be incident, and the measurement light LS1 transmitted through the sample to be measured SMPMEAS are received, photoelectrically converted, and the measurement signal SMEA is measured.
A photodiode 112 that outputs S and a photodiode 11 that receives the measurement light LS2 that has passed through the measurement reference sample SMPREF, performs photoelectric conversion, and outputs a reference signal SREF.
3 and a logarithmic differential amplifier 114 that performs logarithmic differential amplification of the measurement signal SMEAS and the reference signal SREF and outputs the measurement voltage signal VOUT.

In this case, a lens 104, a slit 105, a collimator mirror 106, and a diffraction grating 107
Constitutes a monochromator. Next, the outline operation will be described. The measurement light L ′ emitted from the light source 101 of the absorbance measurement device 100 is
The light is reflected by 3 and enters the monochromator.

The original measurement light L 'incident on the monochromator
Is condensed by the lens 104, passes through the slit 105, is converted into parallel light by the collimator mirror 106, and enters the diffraction grating 107. Diffraction grating 107
The original measurement light L ′ that has entered the measurement light LS that is a spectrum is generated by the mutual interference of the diffracted light of the original measurement light L ′,
The measurement light LS is reflected by the collimator mirror 106.

As a result, the measurement light LS is reflected again by the collimator mirror 106, passes through the slit 105, the lens 104 and the half mirror 103, and passes through the lens 1
08. The lens 108 condenses the measurement light LS and guides the measurement light LS to the beam splitter 109. The beam splitter 109 converts the measurement light LS into two equivalent measurement lights LS.
1 and LS2, the measurement light LS1 is made incident on the sample to be measured SMPMEAS via the mirror 110, and the measurement light LS2
Is incident on the measurement reference sample SMPREF via the mirror 111.

The photodiode 112 receives the measurement light LS1 that has passed through the sample SMPMEAS to be measured, performs photoelectric conversion, and outputs a measurement signal SMEAS to a logarithmic differential amplifier.
The measurement light LS2 that has passed through PREF is received, photoelectrically converted, and a reference signal SREF is output to a logarithmic differential amplifier.

As a result, the logarithmic differential amplifier 114
Performs logarithmic differential amplification of the measurement signal SMEAS and the reference signal SREF, and outputs the result as a measurement voltage signal VOUT. At this time, the absorbance A is represented by A = -VOUT. Second Conventional Example FIG. 9 shows a second conventional example in which measurement light from a plurality of light sources is irradiated on a sample to be measured.

The light absorption characteristic measuring unit 200 has an R (Re
d) R light source 201 for emitting R measurement light LR of a single wavelength component
G that emits G (Green) single wavelength component G measurement light LG
A light source 202, a B light source 203 that emits B (Blue) single wavelength component B measurement light LB, and a 45 [゜] position with respect to the optical axis of the R measurement light LR emitted by the R light source 201. A first half mirror 204, a second half mirror 205 arranged at a position of 45 ° with respect to the optical axis of the G measurement light LG emitted from the G light source 202, and a B measurement light emitted from the B light source 203 The sample SMP ′ to be measured is reflected by the third half mirror 206 and the first half mirror 204 arranged at a position of 45 ° relative to the optical axis of LB.
And the first to third half mirrors 204 to 20
And a photodiode 207 arranged on the optical axis of the R measurement light LR that has passed through 6.

Next, the operation will be described. R measurement light LR emitted from the R light source 201 of the light absorption characteristic measurement unit 200
Is reflected by the first half mirror 204, reflected by the sample to be measured SMP ', transmitted through the first to third half mirrors 204 to 206, and incident on the photodiode 207.

The G measurement light LG emitted from the G light source 202 is reflected by the second half mirror 205, passes through the first half mirror 204, and passes through the sample SM to be measured.
Reflected by P ', and furthermore, the first to third half mirrors 2
The light passes through Nos. 04 to 206 and enters the photodiode 207.

Further, the B measurement light LB emitted from the B light source 203 is reflected by the third half mirror 206, passes through the second half mirror 205 and the first half mirror 204, and is reflected by the sample SMP 'to be measured. First
The light is transmitted through the third half mirrors 204 to 206 and enters the photodiode 207. Third Conventional Example FIG. 10 shows a schematic configuration diagram of an optical system of a color temperature identification device used in a white balance circuit of a video camera or the like.

The color temperature discriminating apparatus 300 includes a light source 301 for emitting a measuring light L "which is white light, and a sample SM to be measured.
Of the measurement light L "transmitted through P", the B photodiode 302 responsible for receiving light in a frequency band centered on the B (Blue) component, and the measurement light L "transmitted through the measurement target sample SMP" G ( Green) The G photodiode 303 responsible for light reception in a frequency band centered on the component, and R out of the measurement light L "transmitted through the measurement sample SMP"
An R photodiode 304 for receiving light in a frequency band centered on the (Red) component.

Next, the operation will be described. The measurement light L ″ emitted from the light source 301 passes through the sample to be measured SMP ″, the B component is received by the B photodiode 302, and G
The component is received by the G photodiode 303, and the R component is received by the R photodiode 304.

Each of the photodiodes 302 to 304
Is amplified by a logarithmic amplifier (not shown), and the color temperature is determined based on the ratio of the B component to the G component, B / G, the ratio of the G component to the R component, and G / R.

[0018]

The first conventional example of the absorbance measuring apparatus requires a complicated optical mechanism such as a slit, a beam splitter, and a mirror group in order to obtain a measuring light having a desired wavelength. There was a problem.

Furthermore, these complex optical systems require delicate mechanism adjustments to fully exhibit their performance, and are periodically performed to correct the deviation of the optical system due to temperature change or aging. There was a problem that calibration was required. Furthermore, a mechanism for maintaining these precise optical systems in an earthquake-proof state is also indispensable, which further complicates the configuration of the light absorption characteristic measuring device.

Since a differential signal is used in principle of measurement, the obtained signal is weak, and there is a problem that the amplification is easily affected by noise and temperature drift. In the optical path before the measurement light emitted from the measurement light source irradiates the sample, slits and a large number of mirrors are interposed, so that the measurement light is largely attenuated along the optical path.

If the output of the light source is increased to compensate for this, heat dissipation from the light source causes an increase in the temperature in the measurement cell holding the sample, resulting in a problem that the measurement accuracy is deteriorated. Conversely, if the light source output is reduced to improve the measurement accuracy, the amount of light irradiated on the sample will be reduced, and the resulting measurement signal (differential signal) will be weak, requiring a signal processing circuit with low noise and high amplification factor. A problem arises.

Further, in the second conventional example, as described above, since the optical axes of the plurality of light sources 201 to 203 are combined by the half mirrors 204 to 206, the irradiation efficiency deteriorates. There was a problem that it would. More specifically, the B measurement light LB emitted from the B light source 203 reduces the reflectance of each half mirror by １ ／ (= 50).
[%]), The overall irradiation efficiency up to the photodiode 207 was 1/64 (= (1/2) ⁶ ), and the irradiation efficiency was extremely poor.

It is ideal to receive only the light components that are absorbed and scattered inside the measurement target sample out of the measurement light applied to the measurement target sample. However, as shown in FIG. In addition, since the emission direction is perpendicular to the surface of the sample to be measured, there is a problem that the measurement light is directly reflected on the surface of the sample to be measured, and a desired signal is masked.

In particular, there is a problem that the measurement becomes difficult when the surface of the sample to be measured is glossy. Furthermore, in the third conventional example, there is a problem that the spectral components contained in the measurement light transmitted through the sample to be measured cannot be quantitatively grasped.

More specifically, even if the color looks green to the naked eye, the spectrum obtained by coloring with a dye that reflects green and the color obtained with a mixture of a dye that absorbs blue and a dye that absorbs yellow are different. Nevertheless, they cannot be identified because the color temperatures are similar.

In a conventional light absorption characteristic measuring apparatus, a light source which emits a light having a large heat effect including infrared rays, far infrared rays, etc. may be used as a light source for measurement, and the sample is heated and dried. There was a problem.
In particular, in the case of performing measurement while exposing a sample, which does not like to be dried by irradiation of measurement light, to the atmosphere as in the reflection measurement of a multilayer analysis film, a measurement light source having a small thermal effect has been desired.

It is an object of the present invention to simplify the optical system, to handle easily, to obtain a large measurement signal, to quantitatively grasp the spectral components, and to prevent the sample from drying. It is an object of the present invention to provide a light absorption characteristic measurement unit and a light absorption characteristic measurement method that can perform the measurement.

[0028]

In order to solve the above-mentioned problems, the invention according to claim 1 has an emission section, and measurement lights having mutually different emission wavelengths are emitted from the emission section based on a drive signal. A plurality of light emitting elements to be emitted, a selection driving means for sequentially selecting one of the light emitting elements based on an instruction from the outside, and outputting the drive signal to drive the light emitting elements, and a light emitting element emitted by the light emitting element and a measuring object And a light-receiving means for receiving the measurement light transmitted through the sample and outputting a light-receiving signal.

According to the first aspect of the present invention, the selection driving means sequentially selects one light emitting element based on an external instruction and outputs a driving signal to drive the light emitting element. Each light emitting element is
Measuring lights having mutually different emission wavelengths are emitted from the emission units based on the drive signals.

Thus, the light receiving means receives the measuring light transmitted through the sample to be measured and outputs a light receiving signal. Claim 2
The described invention has a plurality of light-emitting elements each having an emission unit and emitting measurement lights having mutually different emission wavelengths from the emission unit based on a drive signal, and one of the light-emitting elements based on an external instruction. Selection driving means for sequentially selecting and driving the elements and outputting the driving signal to drive the light receiving means for receiving the measuring light emitted by the light emitting element and reflected by the sample to be measured and outputting a light receiving signal And comprising.

According to the second aspect of the present invention, the selection driving means sequentially selects one light emitting element based on an external instruction and outputs a driving signal to drive it. Each light emitting element is
Measuring lights having mutually different emission wavelengths are emitted from the emission units based on the drive signals.

Thus, the light receiving means receives the measuring light reflected by the sample to be measured and outputs a light receiving signal.
According to a third aspect of the present invention, in the first or the second aspect of the present invention, the light emitting element is disposed in an optical path between the light emitting element and the sample to be measured, and the main light axes of the plurality of light emitting elements substantially coincide with each other. It is provided with a light condensing means.

According to the third aspect of the present invention, in addition to the function of the first or second aspect, the light collecting means is
The main optical axes of the plurality of light emitting elements are made substantially coincident. According to a fourth aspect of the present invention, in the third aspect of the invention, the light condensing means has a prism, and the plurality of light emitting elements are
The angle of incidence of the measurement light on the prism is set and arranged such that the main optical axis of the measurement light emitted from the prism substantially coincides.

According to the fourth aspect of the present invention, in addition to the function of the third aspect of the present invention, the plurality of light emitting elements are arranged so that the main light axis of the measuring light emitted from the prism of the light collecting means is based on the arrangement thereof. Almost match. According to a fifth aspect of the present invention, in the third aspect of the present invention, the light-collecting unit receives the measuring light reflected by the reflecting unit that reflects the measuring light of the corresponding light emitting element. It has a prism, the reflection means and the plurality of light emitting elements, the incident angle of the measurement light to the reflection means and the main light axis of the measurement light emitted from the prism substantially coincide with each other and The angle of incidence of the reflected light of the measurement light by the reflecting means on the prism is set and arranged.

According to the fifth aspect of the present invention, in addition to the function of the third aspect, the reflecting means and the plurality of light emitting elements are arranged so that the measuring means emitted from the prism of the condensing means based on their arrangement. The main optical axes of light are made substantially coincident. The invention according to claim 6 is the invention according to claim 2, wherein a straight line substantially perpendicular to the center of the measurement target of the measurement target sample is assumed, and the straight line is located at a position facing the measurement target sample. The light receiving surface of the light receiving means is disposed, and a hemisphere obtained by dividing a sphere centered on the center of the measurement object on a plane passing through the center of the measurement object and perpendicular to the straight line is assumed, and a main optical axis of the measurement light is defined by the hemisphere. The position including a part of a half line passing through the spherical surface of the hemisphere in the same direction as the light receiving surface with respect to the measurement object center and having the measurement object center as an end point, and where the measurement light is incident on the light reception surface. The above-mentioned injection part is arranged.

According to the invention of claim 6, in addition to the effect of the invention of claim 2, it is possible to suppress the measurement light directly reflected by the surface of the sample to be measured from being incident on the light receiving surface of the light receiving means. In addition, the measurement light can be incident on the light receiving surface of the light receiving means. The invention according to claim 7 is the invention according to claim 2, wherein a straight line substantially perpendicular to the center of the measurement target of the measurement target sample is assumed, and the straight line is located at a position facing the measurement target sample. Arrange the light receiving surface of the light receiving means,
A reflection that reflects the measurement light in the optical path of the measurement light such that the main optical axis of the measurement light emitted from the emission unit passes through the center of the measurement target and the measurement light is incident on the light receiving surface. Means are provided.

According to the seventh aspect of the present invention, in addition to the function of the second aspect of the present invention, the reflecting means includes a main optical axis of the measurement light emitted from the emission section passing through the center of the measurement object, and The measuring light is made incident on the light receiving surface of the light receiving means. The invention according to claim 8 is the invention according to claim 7, wherein one or more planes perpendicular to the straight line are assumed, and the emission unit is arranged on one or more planes among the planes. I do.

According to the eighth aspect of the invention, in addition to the operation of the seventh aspect of the present invention, the emission portion is arranged on one or a plurality of planes, so that the emission characteristics of the vehicle type portion are reduced. The arrangement can be made in consideration of the difference. According to a ninth aspect of the present invention, there is provided an absorption characteristic measuring apparatus including an emission unit, and a plurality of light-emitting elements each configured to emit measurement lights having different emission wavelengths from the emission unit based on a drive signal. A measurement method, sequentially selecting one of the light emitting elements based on an instruction from the outside, a selection driving step of driving the selected light emitting element, and emitted by the light emitting element,
And a light receiving step of receiving the measurement light transmitted through the sample to be measured.

According to the ninth aspect of the present invention, in the selective driving step, one light emitting element is sequentially selected based on an external instruction, and the selected light emitting element is driven. The light receiving step receives the measurement light emitted by the light emitting element and transmitted through the sample to be measured.

According to a tenth aspect of the present invention, there is provided an injection unit,
In an absorption characteristic measuring device including a plurality of light emitting elements each of which emits measurement light having a different emission wavelength from each other based on a drive signal, one of the light emitting elements is sequentially selected based on an external instruction. And a selection driving step of driving the selected light emitting element, and a light receiving step of receiving the measurement light emitted by the light emitting element and reflected by the sample to be measured.

According to the tenth aspect of the present invention, in the selection driving step, one light emitting element is sequentially selected based on an external instruction, and the selected light emitting element is driven. The light receiving step receives the measurement light emitted by the light emitting element and reflected by the sample to be measured.

According to a twelfth aspect of the present invention, in the ninth or tenth aspect of the present invention, at least at the time when the measurement light is incident on the sample to be measured, the main optical axes of the plurality of light emitting elements substantially coincide with each other. And a condensing step. According to the eleventh aspect of the present invention, in addition to the operation of the ninth or tenth aspect, in the light condensing step, at least at the time when the measurement light is incident on the sample to be measured, the light-collecting step is performed. The optical axes are almost aligned.

[0043]

Embodiments of the present invention will now be described with reference to the drawings. First Embodiment FIG. 1 shows a schematic block diagram of a light absorption characteristic measuring device.

The light absorption characteristic measuring apparatus 1 includes a Centronics-compliant printer port (8-bit parallel data line PDL, 1-bit control line CMDL, 1-bit busy (BUSY) line serving as a status information line) of an external control computer 2. And a parallel interface unit 3 for performing an interface operation with BSYL and a 1-bit standby (STB) line STBL which is a status information line.
And a drive control data DDR output from the control unit 4 for controlling the entire light absorption characteristic measuring device 1 based on the control digital data CD inputted through the control unit 4.
Under V control, measurement light L1 having different emission wavelengths from each other
To Ln from the emission sections E1 to En, respectively, where n (n is an integer of 2 or more) light emitting diodes (LEDs) 5-1
A measurement light emitting section 5 having a measurement light beam L1 to Ln which is reflected by or transmitted through a measurement target sample (not shown) and outputs an original detection signal S0. A preamplifier circuit 7 for preamplifying the original detection signal S0 and outputting a preamplification detection signal S1, an amplification circuit 8 for amplifying the preamplification detection signal S1 and outputting it as an amplification detection signal S2, A comparison circuit 9 that outputs the detection signal S by comparing the detection signal S2 with a preset reference detection signal, and an A / D conversion circuit 1 that performs analog / digital conversion of the detection signal S and outputs detection data D.
0 and a plurality of detection data corresponding to the same measurement sample,
That is, one or a plurality of detection data D corresponding to one or a plurality of light emitting diodes specified by the control digital data CD are selected and subjected to parallel / serial conversion, and as serial detection data DS via a busy (BUSY) signal line BSYL. It comprises a serial data signal selection circuit 11 for sequentially outputting, and a diode driving power supply 12 for supplying a driving power supply to the light emitting diodes 5-1 to 5-n.

By the way, since the allowable current of the light emitting diodes 5-1 to 5-n is regulated, if continuous light is to be emitted by the DC power supply, the peak luminance is proportional to the continuous allowable current. Diode drive power supply 12 of embodiment
Is a pulse drive (for example, 1 [ms] every 1 [msec].
ec] is turned on), and the peak luminance is increased. It should be noted that even when another element such as a semiconductor laser is used as the light emitting element, the allowable current is regulated.
Similar handling is possible.

Next, specific examples of the light emitting diodes 5-1 to 5-n will be described. As the light emitting diodes 5-1 to 5-n,
For example, as shown in FIG. 2, the emission wavelength (peak wavelength) is 450 [nm], 470 [nm], 555 [n].
m], 562 [nm], 565 [nm], 590 [n
m], 610 [nm], 623 [nm], 635 [n
m], 644 [nm], 660 [nm], wavelength 700
A plurality of light emitting diodes corresponding to the sample to be measured may be arbitrarily selected and used from among light emitting diodes having different emission wavelengths such as [nm].

The light emission wavelength of the light emitting diode varies in various ways depending on the components and proportions of the semiconductor used as the material. For example, the junction material of the light emitting diode having a light emission wavelength of 590 [nm] is InGaAlP / GaP.

Next, prior to the description of the specific measuring operation, the arrangement of the light emitting diode and the photodiode will be described with reference to FIG.
This will be specifically described with reference to FIGS. 1) In the case of the transmission method First, the arrangement of the light emitting diodes and the photodiodes when measuring the light absorption characteristics of the sample to be measured by the transmission method will be described. In the following description, a case where the number of light emitting diodes is n = 6 will be described for simplification of the description.

As shown in FIG. 3, the light emitting diodes 5-1 to 5-6 are arranged such that their emission portions E1 to E6 are arranged on a virtual straight line VL included in the drawing. A plurality of mirrors M1 to M6 functioning as condensing means and a triangular prism PL are arranged in an optical path between the light source and the photodiode 6.

In this case, the mirrors M1 to M6 reflect the measuring beams L1 to L6 of the corresponding light emitting diodes 5-1 to 5-6 and enter the prism PL. 5-6 and the mirrors M1 to M6 are incident on the mirrors M1 to M6 and the mirrors M1 to M6 so that the main optical axes of the measurement lights L1 to L6 emitted from the prism PL are substantially coincident with each other. The angles of incidence of the reflected lights of the measurement lights L1 to L6 for M6 on the prism PL are set and arranged.

It should be noted that the main optical axes do not need to be strictly coincident as long as the measurement light beams L1 to L6 are incident on a region where the sample SMP to be measured can be considered to be sufficiently uniform. As a result, since the reflection loss in the mirrors M1 to M6 and the prism PL is extremely small, the irradiation efficiency of the measurement light can be kept very high, and highly accurate measurement can be performed.

In the above configuration, the light emitting diodes 5-1 to 5-6
Of the light emitting diodes 5-1 to 5-6 based on the light emitting characteristics of the light emitting diodes 5-1 to 5-6. Section E1 ~
The distance from E6 to the photodiode 6 can be set as appropriate.

In the above configuration, the measuring light beams L1 to L6 are incident on the prism PL via the mirrors M1 to M6. However, the arrangement of the light emitting diodes, restrictions on assembly, and restrictions on the dimensions of the device are taken into consideration. Otherwise, the light-emitting diodes 5-1 to 5-6 can be arranged so that the measuring lights L1 to L6 are directly incident on the prism PL from the light-emitting diodes 5-1 to 5-6.

For example, the light emitting diodes 5-1 to 5-6 may be arranged at the positions of the mirrors M1 to M6. 2) In the case of the reflection method Next, the arrangement of the light emitting diodes and the photodiodes when measuring the light absorption characteristics of the sample to be measured by the reflection method will be described.

2-1) Configuration using a mirror and a prism
As shown in FIG. 4, the light emitting diodes 5-1 to 5-6 are arranged such that their emission portions E1 to E6 are arranged on a virtual straight line VL included in the drawing. 1-5
A plurality of mirrors M1 to M6 functioning as light collecting means and a triangular prism-shaped prism PL are arranged in an optical path between the photodiode -6 and the photodiode 6.

Also in this case, the mirrors M1 to M6 are
The measuring light beams L1 to L6 of the corresponding light emitting diodes 5-1 to 5-6 are reflected and incident on the prism PL.
The light emitting diodes 5-1 to 5-6 and the mirrors M1 to M6 are incident on the mirrors M1 to M6 of the measuring lights L1 to L6 such that the main optical axes of the measuring lights L1 to L6 emitted from the prism PL are substantially coincident. The angles and the angles of incidence of the reflected lights of the measuring lights L1 to L6 on the mirrors M1 to M6 to the prism PL are set and arranged.

However, the incident angle θIN of the measurement light L1 to L6 emitted from the prism PL with respect to the measurement target sample is set so that the direction angle θOUT of the photodiode 6 with respect to the normal LX of the measurement target sample SMP is different from the incident angle θIN as appropriate. That is, θIN ≠ θOUT must be satisfied. This is because if θIN = θOUT, the measurement lights L1 to L6 directly reflected on the surface of the measurement target sample SMP enter the photodiode 6, but the measurement lights L1 to L6 directly reflected on the surface of the measurement target sample SMP. Does not reflect the light absorption characteristics of the sample to be measured, so that measurement including an error is performed.

Therefore, the direction angle θ OUT needs to be set to an appropriate angle in consideration of the decrease in the amount of incident light on the photodiode 6 and the amount of incident measuring light reflected on the surface of the sample SMP to be measured. More specifically, the measurement target sample S
The measurement light (directly reflected light) directly reflected on the MP surface is less incident on the photodiode 6, and the measurement light (measurement target reflected light) partially absorbed and reflected inside the measurement target sample SMP is incident on the photodiode 6. The direction angle θOUT is set so that the amount of incident light is sufficient for the measurement. For example, with respect to the output angle of the direct reflection angle, the direction angle θOUT is set to 10 [゜] to 60.
[゜] Shift and set.

As in the case of the transmission method, the measurement light L1 is set in a region where the sample SMP to be measured is considered to be sufficiently uniform.
If ~ L6 is incident, it is not necessary to make the main optical axes exactly coincide. In the above description, the emission portions E1 to E6 of the light-emitting diodes 5-1 to 5-6 are arranged so as to be arranged on a virtual straight line VL included in the paper for ease of assembly. The arrangement is arbitrary as long as the emission sections E1 to E6 are opposed to the mirrors M1 to M6 and the amount of incident light on the photodiode 6 is secured. Conversely, in order to adjust the light amount in consideration of the difference in the light emission characteristics of the respective light emitting diodes 5-1 to 5-6, it is also possible to arrange the optical path length up to the photodiode 6 as appropriate. is there.

2-2) Directly irradiate the measurement light to the sample to be measured
In the case of a configuration in which light is emitted, the light emitting diodes 5-1 to 5-6 are connected to the respective emission portions E1 to E6 as shown in FIGS. 5 (a) and 5 (b).
Assuming a sphere CC centered at the center P0 of the MP to be measured,
The main optical axes of the measurement lights L1 to L6 are placed on a circle CL which is a spherical curve obtained by intersecting a plane PP perpendicular to a virtual straight line LL1 passing through the center (= P0) of the sphere CC and the sphere of the sphere CC. It is arranged to pass through the center (= P0) of the sphere CC.

Further, the light receiving surface of the photodiode 6 is arranged on the virtual straight line LL1. Therefore, the above (2-
As in the case of 1), it is possible to suppress the measurement light L1 to L6 directly reflected on the surface of the measurement target sample SMP from being incident on the photodiode 6.

The arrangement of the light emitting diodes 5-1 to 5-6 is as follows.
As an example, a straight line substantially perpendicular to the center P0 of the measurement target sample SMP is assumed, and the photodiode 6 is located on this virtual straight line at a position facing the measurement target sample SMP.
Assuming a hemisphere obtained by dividing a sphere centered on the measurement target center P0 on a plane passing through the measurement target center P0 and perpendicular to the virtual straight line, the main optical axis of the measurement light L1 to L6 is a hemisphere. Of these, a part of a half line passing through a hemispherical spherical surface in the same direction as the light receiving surface of the photodiode 6 with respect to the measurement target center and having the measurement target center P0 as an end point is included, and the measurement lights L1 to L6 are included.
The same effect can be obtained by arranging the emission portions E1 to E6 at positions where the light enters the light receiving surface of the photodiode 6.

2-3) The measurement light is transmitted to the measurement tube via the reflection tube.
In the case of a configuration for irradiating an elephant sample, the light receiving surface of the photodiode 6 is on a virtual straight line LL1 passing through the center P0 of the measurement target sample SMP as shown in FIGS. It is arranged at a position facing the target sample SMP.

The light emitting diodes 5-1 to 5-6 assume a plane PP1 perpendicular to the virtual straight line LL1, and
The emission portions E1 to E6 are arranged on the circumference of the circle CL1 on the plane PP1 centered on the intersection X0 of the plane PP1 and the plane PP1. Further, the measurement light L1 is placed in the optical path of the measurement light L1 to L6 such that the main optical axis of the measurement light L1 to L6 passes through the center P0 of the sample SMP to be measured.
A reflection tube 20 for reflecting .about.L6 is arranged.

As a result, as in the case of the above (2-1), the measurement light L directly reflected on the surface of the sample SMP to be measured is obtained.
1 to L6 can be suppressed from being incident on the photodiode 6. The arrangement of the light emitting diodes 5-1 to 5-6 is as follows.
As an example, a straight line substantially perpendicular to the center P0 of the measurement target sample SMP is assumed, and the photodiode 6 is located on this virtual straight line at a position facing the measurement target sample SMP.
Are arranged, the main optical axes of the measuring lights L1 to L6 emitted from the emitting portions E1 to E6 pass through the center P0 of the measurement object, and
The same effect can be obtained by providing a similar reflection means (mirror or the like) for reflecting the measurement lights L1 to L6 in the optical path of the measurement lights L1 to L6 so that the measurement lights L1 to L6 enter the light receiving surface of the photodiode 6. can get. The measuring operation then concrete measurement operation of the embodiment will be described.

First, the external control computer 2 operates in accordance with a procedure programmed in advance by the operation of the operator.
The measurement control data group is output to the parallel interface unit 3 of the light absorption characteristic measuring device 1 via a Centronics-compliant printer port. Thereby, the parallel interface unit 3 performs an interface operation, and transmits the control digital data CD to the control unit 4 and the serial data transfer signal selection circuit 1 via the parallel data line PDL.
1 and outputs a control signal to the control unit 4 via the control line CMDL.

The control section 4 latches the control digital data CD and the control signal in the signal holding circuit (data latch) 4A, and outputs the drive control data DDRV to the measurement light emitting section 5 by the light emitting element selection circuit 4B. Based on the drive control data DDRV, the measurement light emitting unit 5 transmits one or a plurality of light emitting diodes corresponding to the drive control data DDRV to a predetermined time interval (measurement time interval) using a drive power supply supplied from the diode drive power supply 12. ). In this case, the pulse voltage applied to each light emitting diode is corrected according to the light emitting characteristics of each light emitting diode.

Thus, the photodiode 6 receives the measurement lights L1 to Ln reflected by or transmitted through the sample to be measured SMP (see FIGS. 3 to 6), and pre-amplifies the original detection signal S0. Output to the circuit 7. The preamplifier circuit 7 preamplifies the original detection signal S0 and outputs a preamplification detection signal S1 to the amplifier circuit 8.

The amplification circuit 8 amplifies the pre-amplification detection signal S1 and outputs it to the comparison circuit 9 as an amplification detection signal S2.
The comparison circuit 9 outputs the detection signal S to the A / D conversion circuit 10 by comparing the amplified detection signal S2 with a preset reference detection signal. The A / D conversion circuit 10 performs analog / digital conversion of the detection signal S, and converts the detection data D into a serial data transfer signal selection circuit 11, which outputs a plurality of pieces of detection data corresponding to the same sample to be measured, that is, control digital data CD. , Select one or a plurality of detection data D corresponding to one or a plurality of light emitting diodes, convert the data into parallel / serial, and output the detected data D as serial detection data DS via a busy (BUSY) signal line BSYL to an external control computer 2. Are output sequentially.

As a result, the external control computer 2
Represents one or a plurality of input serial detection data DS
The qualitative analysis process or the quantitative analysis process is performed based on the absorption characteristics of a single wavelength or the absorption characteristics of a plurality of wavelengths based on the above, and the result of the absorption characteristic measurement is displayed on a display (not shown).

According to the present embodiment as described above,
Despite having a simple optical system, it is possible to compare the absorbance values of a sample to be measured based on a plurality of detection data D obtained by a plurality of light emitting diodes (light emitting elements) having different emission wavelengths. Measurement (calibration) with higher accuracy than measurement can be performed. As a result, the measurement of the reference system can be omitted. Further, as a result of the simplification of the optical system, the attenuation of the measurement light is reduced, so that it is not necessary to use a high-amplification amplifier in the subsequent stage, and the effects of noise and temperature drift can be reduced.

In the above description, a light emitting diode is used as a light emitting element. However, a light source that generates less heat, such as a semiconductor laser, can be used. Furthermore, since the heat generation of the light source and the heat energy contained in the measurement light can be reduced, it is possible to suppress the drying of the sample to be measured.

Further, the apparatus configuration is simplified, and there is no need to provide a complicated optical system, so that a stable and economical light absorption characteristic measuring apparatus can be realized. In addition, with the simplification of the device configuration, the operation can be easily performed via the control computer, so that it can be used for science education at elementary and junior high schools, home clinical examinations, outdoor environmental examinations by ordinary citizens, etc. In addition, an operator who is not proficient in the operation of the device can easily measure the light absorption characteristics (colorimetric measurement). Modification of First Embodiment The wavelength range that can be measured by the light absorption characteristic measuring device 1 is determined by a combination of light emitting elements (light emitting diodes).

Accordingly, as the number of light-emitting elements having different emission wavelengths is increased and the overall emission wavelength range is broadened, measurement with higher bandwidth and higher resolution is possible. However, in a measurement device having a limited use, such as comparison of leaf color of agricultural crops or analysis of blood, urine, etc., since a reagent and an absorption wavelength are determined, broadband measurement is unnecessary.

For example, a slide for measuring glucose will be described as an example. The glucose measurement slide film is obtained by dispersing a well-known grinder reagent (such as glucose oxidase, peroxidase, aminoantipyrine and dihydronaphthalene) as a detection reagent in gelatin.

When blood is dropped on the glucose measuring slide film, glucose in the blood diffuses into the reagent layer impregnated with the grinder reagent, and is degraded by glucose oxidase to progress the reaction with the grinder reagent. Progress quantitatively.

The absorption wavelength of the dye produced by the glucose decomposition reaction is around 505 [nm]. However, as shown in FIG. 2, since there is no light emitting diode having an emission wavelength of 505 [nm], absorption measurement at a single wavelength using a light emitting diode having an emission wavelength near the absorption wavelength of this dye is fundamental. It is possible.

However, in reality, the following factors are complicatedly involved and quantification is difficult. 1) Amplification rate adjustment error of the preamplifier circuit 7 or the amplification circuit 8 for amplifying the original detection signal 2) Drift of the preamplification circuit 7 or the amplification circuit 8 3) Luminance adjustment error of the light emitting diode 4) Measurement target sample SMP Fluctuation of light emitting and receiving angles due to errors in holding posture 5) Difference in characteristics of reagent layer of slide film for glucose measurement 6) Reaction speed and coloration error due to temperature difference Therefore, in order to eliminate measurement errors due to these factors Then, measurement light from a light-emitting diode having an emission wavelength that is not absorbed by a glucose measurement slide film, which is a measurement target sample, is irradiated as reference light to obtain detection data D as reference data.

Then, while holding the measurement object, measurement light is emitted from a light-emitting diode having a wavelength closest to the absorption wavelength of the glucose measurement slide film as the measurement object sample, and the detection data D as measurement data is obtained. obtain. Thus, the external control computer performs the quantification by obtaining the difference or ratio between the obtained detection data D as the reference data and the detection data as the measurement data, and displays the difference on a display (not shown).

According to this method, compared to the conventional method of measuring two different samples, that is, a test sample and a reference sample, using two measurement systems, it is possible to perform a simpler measurement with less error. It becomes possible. Second Embodiment Next, a description will be given of a second embodiment in which an absorption characteristic measuring device is configured as a color temperature identification device.

In the case of the second embodiment, the structure of the light absorption characteristic measuring apparatus is the same as that of the first embodiment. Therefore, only the arrangement of the photodiode corresponding to the light emitting diode and the sample to be measured are shown in FIG. It will be described with reference to FIG.
In the following description, a case where the number of light emitting diodes is n = 3 will be described.

The light emitting diode 5-1 having an emission wavelength corresponding to red is arranged at a position facing the corresponding photodiode 6-1 via the sample SMP to be measured.
Similarly, the light emitting diode 5-2 having an emission wavelength corresponding to green is disposed at a position facing the corresponding photodiode 6-2 via the sample to be measured SMP, and the light emitting diode 5 having an emission wavelength corresponding to blue is provided. -3 is disposed at a position facing the corresponding photodiode 6-3 via the measurement target sample SMP.

As a result, even if the color appears green to the naked eye, the coloring by the dye that does not absorb green and the coloring by the mixture of the dye that does not absorb blue and the dye that does not absorb yellow can be easily distinguished because the spectra are completely different. Can be. In this case, each of the light emitting diodes 5-1 to 5-1-5
The lighting of -3 may be performed sequentially, but since separate photodiodes 6-1 to 6-3 are provided, it is also possible to configure so that the lighting is performed at the same time and the measurement is completed instantaneously. Modification of Second Embodiment In the second embodiment, a light receiving element (photodiode) corresponding to each light emitting element (light emitting diode) is used.
Is provided, a plurality of corresponding signal processing circuits must be provided, and the device configuration becomes complicated.

Further, when each light emitting element is turned on at the same time, a measurement error due to light ray leakage is likely to occur. Therefore, as shown in FIG. 7B, only a plurality of light emitting diodes as light emitting elements (three in the figure; light emitting diodes 5-1 to 5-3) are provided.
The light-emitting diodes 5-1 to 5-3 are sequentially turned on to scan the light-emitting diodes 5-1 to 5-3 so that the light is incident on one photodiode 6-4, so that the configuration of the light-receiving system can be simplified.

In each of the above embodiments, the external control computer and the light absorption characteristic measuring device are connected via the Centronics-compliant printer port, but the data input / output control is performed by a known method. , Serial I / O port (for example, RS232C) universal I
It is also possible to use another known interface circuit such as an / O bus.

Further, the present embodiment can be applied to a sample to be measured, whether it is a gas, a liquid, or a solid, by performing a container shape or a reflection measurement or a transmission measurement. As described above, according to each embodiment, the optical system can be simplified, the operation can be simplified, and the apparatus cost can be reduced. It is easy to handle even for a user who is not very skilled, and can be used as an absorption characteristic measuring device for learning or an absorption characteristic measuring device for home care.

[0087]

According to the first aspect of the present invention, the selection driving means sequentially selects one light emitting element based on an external instruction and outputs a driving signal to drive the light emitting element.
Based on the drive signal, measurement light beams having different emission wavelengths are emitted from the emission units, and the light receiving unit receives the measurement light transmitted through the sample to be measured and outputs a light reception signal, thereby simplifying the optical system. Can be handled easily.

As a result of the simplification of the optical system, the signal intensity in the light receiving means is increased, the signal can be handled at a low amplification rate, and the influence of noise and temperature drift is reduced. Further, since a plurality of light emitting elements having different emission wavelengths are sequentially driven, the spectral components can be grasped quantitatively.

Further, when a light emitting diode, a laser diode, or the like is used as the light emitting element, since there is almost no emission of infrared light, it is possible to prevent the sample to be measured from being dried. A measurement can be made. According to the second aspect of the invention, the selection driving means sequentially selects one light emitting element based on an external instruction and outputs a driving signal to drive the light emitting element.
Based on the drive signal, the measuring unit emits measurement lights having mutually different emission wavelengths from the emission unit, and the light receiving unit receives the measurement light reflected by the measurement target sample and outputs a light reception signal. Also, the optical system can be simplified, and handling becomes easy.

As a result of the simplification of the optical system, the signal intensity in the light receiving means is increased, the signal can be handled with a low amplification factor, and the influence of noise and temperature drift is reduced. Further, since a plurality of light emitting elements having different emission wavelengths are sequentially driven, the spectral components can be grasped quantitatively.

Furthermore, when a light emitting diode, a laser diode, or the like is used as the light emitting element, infrared rays are hardly emitted, so that the sample to be measured can be prevented from drying. A measurement can be made. According to the invention set forth in claim 3, claim 1 is provided.
Alternatively, in addition to the effect of the invention described in claim 2, since the condensing means makes the main optical axes of the plurality of light emitting elements substantially coincide with each other, measurement conditions can be shared between the plurality of light emitting elements, and the measurement result can be obtained. Reliability can be improved.

According to the fourth aspect of the invention, in addition to the effect of the third aspect, the plurality of light-emitting elements are arranged on the main optical axis of the measurement light emitted from the prism of the condensing means based on the arrangement thereof. Are substantially the same, so that the measurement conditions can be shared among a plurality of light emitting elements, and the reliability of the measurement results can be improved, although the optical system can be simplified.

According to the fifth aspect of the present invention, in addition to the effect of the third aspect, the reflecting means and the plurality of light-emitting elements are measured based on their arrangement and emitted from the prism of the condensing means. Since the main optical axes of light are substantially coincident with each other, the arrangement of the light emitting elements can be facilitated, and the measurement conditions can be shared among a plurality of light emitting elements despite the fact that the optical system can be simplified. The reliability of the measurement result can be improved.

According to the sixth aspect of the invention, in addition to the effect of the second aspect, it is possible to suppress the measurement light directly reflected by the surface of the sample to be measured from being incident on the light receiving surface of the light receiving means. In addition, since the measurement light can be made incident on the light receiving surface of the light receiving means, an accurate measurement result can be obtained without masking the measurement light even if the measurement target sample has a glossy surface.

According to the seventh aspect of the present invention, in addition to the effect of the second aspect, the reflecting means allows the main optical axis of the measuring light emitted from the emitting portion to pass through the center of the measuring object, and Since the measurement light is incident on the light-receiving surface of the light-receiving means, the optical system can be simplified, and the measurement light can be accurately measured without masking even if the measurement target sample has a glossy surface. The result can be obtained.

According to the eighth aspect of the present invention, in addition to the effect of the seventh aspect of the present invention, the emission portion is arranged on one or a plurality of planes in the vehicle type portion, so that the light emission characteristic is reduced. The arrangement can be made in consideration of the difference, the degree of freedom in design can be improved, and the measurement conditions can be shared among a plurality of light emitting elements, so that the reliability of the measurement results can be improved.

According to the ninth aspect of the invention, in the selection driving step, one light emitting element is sequentially selected based on an external instruction, and the selected light emitting element is driven. In the light receiving step, the light emitting element emits light. In addition, since the measurement light transmitted through the sample to be measured is received, the optical system can be simplified and the handling becomes easy. Further, since a plurality of light emitting elements having different emission wavelengths are sequentially driven, the spectral components can be grasped quantitatively.

According to the tenth aspect, in the selection driving step, one light emitting element is sequentially selected based on an external instruction, and the selected light emitting element is driven. In the light receiving step, the light emitting element emits light. In addition, since the measurement light reflected by the sample to be measured is received, the optical system can be simplified even in the reflection optical system, and the handling becomes easy.

Further, since a plurality of light emitting elements having different emission wavelengths are sequentially driven, the spectral components can be grasped quantitatively. According to the eleventh aspect, in addition to the effect of the ninth or tenth aspect, the light condensing step is performed at least when the measurement light is incident on the sample to be measured. Since the optical axes almost coincide,
Despite the simplification of the optical system, measurement conditions can be shared among a plurality of light emitting elements, and the reliability of measurement results can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration block diagram of a light absorption characteristic measuring device.

FIG. 2 is a diagram illustrating a material of a light emitting diode.

FIG. 3 is an explanatory diagram of a transmission optical system according to the first embodiment.

FIG. 4 is an explanatory diagram of a reflective optical system according to the first embodiment.

FIG. 5 is an explanatory diagram in a case where measurement light is directly applied to a sample to be measured in the first embodiment.

FIG. 6 is an explanatory diagram in a case where the measurement light is indirectly applied to the measurement target sample in the first embodiment.

FIG. 7 is an explanatory diagram of the second embodiment.

FIG. 8 is a schematic configuration diagram of a conventional absorbance measuring device.

FIG. 9 is an explanatory diagram of a conventional optical system using a plurality of light sources.

FIG. 10 is an explanatory diagram of an optical system of a conventional color temperature identification device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Absorption characteristic measuring device 2 Control computer 3 Parallel interface unit 4 Control unit 5 Measurement light emitting unit 5-1 to 5-n Light emitting diode (LED) 6 Photodiode 7 Preamplifier circuit 8 Amplifier circuit 9 Comparison circuit 10 A / D conversion circuit 11 Serial data signal selection circuit 12 Diode drive power supply CD control digital data DDRV drive control data D detection data DS serial detection data E1 to En emission unit L1 to Ln measurement light S detection signal S0 original detection signal S1 preamplification detection Signal S2 amplification detection signal

Claims (11)

[Claims] 1. A plurality of light-emitting elements each having an emission unit for emitting measurement lights having mutually different emission wavelengths based on a drive signal from the emission unit, and one of the light-emitting devices based on an external instruction. Selecting drive means for sequentially selecting elements and outputting the drive signal for driving; light receiving means for receiving the measurement light emitted by the light emitting element and passing through the sample to be measured and outputting a light reception signal; A light absorption characteristic measurement unit comprising: 2. A plurality of light-emitting elements each having an emission unit for emitting measurement lights having mutually different emission wavelengths based on a drive signal from the emission unit, and one of the light-emitting devices based on an external instruction. Selection drive means for sequentially selecting and driving the elements and outputting the drive signal for driving; light receiving means for receiving the measurement light emitted by the light emitting element and reflected by the sample to be measured and outputting a light reception signal And a light absorption characteristic measurement unit comprising: 3. The light-absorbing characteristic measuring unit according to claim 1, wherein the light-emitting element is disposed in an optical path between the light-emitting element and the sample to be measured, and the main light axes of the plurality of light-emitting elements are substantially coincident with each other. A light absorption characteristic measuring unit comprising a light condensing means for causing the light to be absorbed. 4. The light absorption characteristic measuring unit according to claim 3, wherein the light condensing means has a prism, and the plurality of light emitting elements have a main optical axis of the measurement light emitted from the prism. An absorption characteristic measuring unit, wherein an incident angle of the measuring light to the prism is set and arranged so as to substantially coincide with each other. 5. The light-absorbing characteristic measuring unit according to claim 3, wherein the light-collecting unit receives the measurement light reflected by the reflection unit and the measurement light reflected by the corresponding light-emitting element. A prism, and the reflecting unit and the plurality of light emitting elements are configured such that an angle of incidence of the measuring light on the reflecting unit and the angle of incidence of the measuring light so that a main optical axis of the measuring light emitted from the prism substantially coincides. An absorption characteristic measuring unit, wherein an incident angle of the reflected light of the measurement light by the reflection means to the prism is set and arranged. 6. The absorption characteristic measuring unit according to claim 2, wherein a straight line substantially perpendicular to the center of the measurement target of the measurement target sample is assumed, and the straight line is located at a position facing the measurement target sample on the straight line. Arranging the light receiving surface of the light receiving means, assuming a hemisphere obtained by dividing a sphere centered on the center of the measuring object on a plane passing through the center of the measuring object and perpendicular to the straight line, the main optical axis of the measuring light is defined by the hemisphere. The position including a part of a half line passing through the spherical surface of the hemisphere in the same direction as the light receiving surface with respect to the measurement object center and having the measurement object center as an end point, and where the measurement light is incident on the light reception surface. A light-absorbing characteristic measuring unit, wherein the light-emitting section is disposed in the light-emitting section. 7. The light absorption characteristic measurement unit according to claim 2, wherein a straight line substantially perpendicular to a center of the measurement target of the measurement target sample is assumed, and the straight line is located on a position facing the measurement target sample on the straight line. A light receiving surface of a light receiving unit is arranged, and an optical path of the measurement light so that a main optical axis of the measurement light emitted from the emission unit passes through the center of the measurement target and the measurement light is incident on the light reception surface. A light absorption characteristic measurement unit, wherein a reflection means for reflecting the measurement light is provided therein. 8. The light absorption characteristic measurement unit according to claim 7, wherein one or more planes perpendicular to the straight line are assumed, and the emission unit is arranged on one or more planes among the planes. Characteristic absorption measurement unit. 9. An absorption characteristic measuring method in an absorption characteristic measuring apparatus having an emission unit and having a plurality of light emitting elements each emitting measurement light having a different emission wavelength from each other based on a drive signal from the emission unit. A selection driving step of sequentially selecting one of the light emitting elements based on an instruction from the outside, and driving the selected light emitting element; and the light emitting element being emitted by the light emitting element and transmitting the sample to be measured. A method for measuring light absorption characteristics, comprising: a light receiving step of receiving measurement light. 10. An absorption characteristic measuring method in an absorption characteristic measuring apparatus, comprising: an emission unit; and a plurality of light-emitting elements that emit measurement lights having mutually different emission wavelengths from the emission unit based on a drive signal. A selection driving step of sequentially selecting one of the light-emitting elements based on an external instruction and driving the selected light-emitting element; emitted by the light-emitting element, and reflected by the sample to be measured. A light-receiving step of receiving the measurement light. 11. The light-absorbing characteristic measuring method according to claim 9, wherein at least at the time when the measuring light is incident on the sample to be measured, the main light axes of the plurality of light-emitting elements are substantially coincident. A method for measuring light absorption characteristics, comprising a step.