JPS6147524A - Spectrophotometer - Google Patents

Abstract

PURPOSE:To measure the spectral characteristic of the light from a light emitting or light reflective object within a short time with high accuracy, by arranging a wedge shaped transparent plate between an object to be measured and the incident slit of a spectroscope in a contact state. CONSTITUTION:At first, an object 8 to be measured is not arranged and a standard light source, of which the spectral energy distribution is known, is arranged and the spectral energy of the transmitted light from a polarization eliminating plate 10, wherein two same wedge shaped crystal plates 17, 17 are arranged opposedly so as to mutually shift the crystal axes thereof by 45 deg. to each other to be capable of not polarizing the light emitted or reflected from the object 8 to be measured, is calculated. The detection value in a photomultiplier 23 is calculated and stored in a memory part 24 as a reference value through an amplifier 15. Next, the standard light source is removed and the object 8 to be measured is arranged to similarly perform measurement. In order to accurately calculate the detection values, the detection value in the photomultiplier 23 amplified by the amplifier 15 is divided by the reference value stored in the memory part 24 through an operation part 25 and the obtained value is multiplied by the spectral energy of the standard light source and the spectral energy of the light emitted from the object 8 to be measured is calculated by a formula.

Description

TECHNICAL FIELD The present invention relates to a spectrophotometer for measuring the spectral properties of light from a luminescent or reflective object.

Prior Art Conventionally, a spectrophotometer of the type described above has been constructed as shown in FIG. The configuration of the prior art and problems with the configuration will be described below with reference to FIG.

In Fig. 3, 1 indicates an object to be measured such as a light-emitting object or a reflective object, and light 2 emitted or reflected from the object 1 to be measured is
is condensed near the entrance slit of the spectrometer 4 via the condensing optical system 3. The incident light focused near the entrance slit of the spectrometer 4 is separated into spectra through the spectrometer 4 and then emitted. 5 is a light receiving element for detecting the amount of light emitted from the spectrometer 4, and the output of the amount of emitted light detected by this light receiving element 5 is sent to an amplifier 6.
The amplifier 6 is connected to a display section 7 so that the output value of the amplifier 6 can be displayed.

According to the above configuration, the spectral characteristics of light emitted or reflected from the object to be measured 1 can be measured by observing the values displayed on the display section 9.

However, the above conventional technology has the following problems. That is, in general, light emitted from a light-emitting object or a reflective object, which is the object to be measured 1, is not unpolarized light but exhibits various polarizations. Since the spectrometer 4 is usually configured with a mirror, the amount of output light will vary depending on the polarization state of the incident light.

Therefore, the spectral characteristics that are the measurement results change depending on the relative positional relationship between the spectrometer 4 and the rotational position of the object to be measured 1, resulting in poor reproducibility. That is, in the case of an object to be measured that does not emit unpolarized light, the measurement reproducibility is significantly deteriorated. Therefore, in order to solve this problem, a wavelength plate (not shown) is disposed between the object to be measured 1 and the spectrometer 4, and this wavelength plate is rotated via a motor or the like, so that the rotational position Measures have been taken to smooth out changes in spectral characteristics and obtain uniform measurement results of spectral characteristics.

However, the above-mentioned means requires a rotating drive mechanism for the wave plate as an essential component, which not only makes the apparatus complicated and bulky but also requires a long measurement time.

Purpose of the Invention The present invention has been made in view of the problems of the prior art described above, and is a spectroscopy method that enables the spectral characteristics of light from a light-emitting object or a reflecting object to be measured in a short time and with high precision. The purpose is to provide a photometer.

Summary of the Invention The present invention involves joining a plurality of wedge-shaped transparent plates made of a material with birefringence between an object to be measured such as a light-emitting object and an entrance slit of a spectroscope so that the crystal axes of each plate are shifted by 45 degrees. By arranging and configuring the apparatus, the above object of the present invention is achieved.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 and 2. Note that FIG. 1 shows the configuration of a specific embodiment of the present invention, and FIG. 2 shows the basic configuration of the present invention. First, the basic configuration of the present invention will be explained using FIG. 2.

In FIG. 1, 8 indicates an object to be measured such as a light-emitting object or a reflecting object. Light 9 emitted or reflected from the object to be measured 8 is incident on the condensing optical system 11 via the depolarization plate 10, and the light emitted from the condensing optical system 11 is condensed near the entrance slit of the spectrometer 12. It is supposed to be illuminated.

The depolarizing plate 10 is for depolarizing the emitted or reflected light from the object to be measured 8 and inputting it into the input slit of the spectrometer 12, and includes a plurality of transparent plates 13 in the form of a double refraction material. 13 are bonded and arranged so that each crystal axis is sequentially shifted by 45 degrees, and the two sides in the optical axis direction are parallel to each other after bonding.

The incident light focused near the entrance slit of the spectrometer 12 is
The light is separated by a spectroscope 12 and then emitted. Reference numeral 14 denotes a light receiving element for detecting the amount of light emitted from the spectroscope 12, and the output of the amount of emitted light detected by this light receiving element 14 is amplified via an amplifier 15. The amplifier 15 is connected to a display section 16 so that the output value from the amplifier 15 can be displayed.

The operation of the above configuration will be explained below.
In order to understand the function of 0, first consider a state in which the depolarizing plate 10 is not provided.

Let m:n be the component intensity ratio of the emitted light from the object to be measured 8 in the same direction as the P direction and the S direction of the spectrometer 12, and let the transmittance of the spectrometer 12 for the P component and the S component be sr, respectively.
, Ss, the measured value E of the spectral energy at this time can be expressed as E=(mSp + n S5)m+n. However, P is the total amount of light incident on the spectrometer 12. In the above formula, E
The condition for determining the value of is 5P=ss. However, since the spectrometer 12 is usually composed of mirrors, sr
and sB are not equal to each other, and the values of m and n change according to the rotation of the object to be measured 8. Therefore, the measured value E in the above formula differs depending on the rotational position of the object to be measured 8, resulting in significantly poor measurement reproducibility. That is, in the case of the object 8 to be measured that does not emit or reflect unpolarized light, the measurement reproducibility of C2 will be significantly worse if the depolarization plate 10 is not provided.

Therefore, next, consider a case where the depolarization plate 10 is disposed between the object to be measured 8 and the condensing optical system 11. Depolarizing plate 10
has the function of converting the light emitted or reflected from the object to be measured 8 into almost completely unpolarized transmitted light, regardless of the polarization state, without loss of light quantity. , the measured value E of the spectral energy when this depolarizing plate 10 is interposed is E = -! −(Sp + Ss). As can be seen from the Kono equation, the measured value E is constant regardless of m and n, that is, regardless of the orientation of the object to be measured 8, and is a measured value proportional to the total light @P incident on the spectrometer 12. Therefore, according to the configuration of the present invention, the spectral energy of light from a light-emitting object or a reflecting object can be measured in a short period of time and with high precision.

Fig. 1 shows an embodiment in which the basic configuration of Fig. 2 is implemented.Hereinafter, members having the same functions as those shown in Fig. 2 are given the same reference numerals. Its configuration will be explained.

The depolarizing plate 10 disposed between the object to be measured 8 and the condensing optical system 11 is made of two identical wedge-shaped plates so that the light emitted or reflected from the object to be measured 8 can be depolarized. crystal plate 1
7 and 17 are arranged facing each other so that their crystal axes are shifted by 45 degrees, and a transparent plate 18 having almost the same refractive index as the crystal is interposed between these two crystal plates 17 and 17. The two plate members 17 and 18 are bonded to each other so that both end surfaces in the optical axis direction after bonding are parallel to each other.

The condensing optical system 11 is for condensing the light from the object to be measured 8 near the entrance slit of the spectrometer 12. The diaphragm 20, the switching mirror 21, and the second imaging lens 22 form an S configuration.

The emitted light from the condensing optical system 11 enters the spectroscope 12, and the amount of the emitted light that is separated and emitted by the spectrometer 12 is detected via the photomulti 23, and the output of the photomulti 23 is increased. The signal is amplified via an 11-channel amplifier 15. The detected value at the photomultiply 23 is stored in the storage section 24, and the detected value at the photomultiply 23 amplified by the amplifier 15 is sent to the storage section 24 via the calculation section 25. The output value is divided by the value of and multiplied by a constant, and the output value is printed out via the printer 26.

The switching mirror 21 of the condensing optical system 11 is configured to be switchable so that it can be set at the position shown by the broken line in the figure during measurement operations and at the position shown by the solid line in the figure during observation. 27
28 is a third imaging lens for forming an observation image when the switching mirror 21 is switched to the observation position, and 28 is an eyepiece lens for observing the observation image.

The operation of the above configuration will be explained.

Initially, the object to be measured 8 is not placed, and instead a standard light source whose spectral energy distribution is known is placed.

Here, the wavelength of light is λ, and the spectral energy of the standard light source is E
(λ), and the energy components in the P direction and the S direction with respect to the spectrometer 12 are respectively set as EP(λL Es(λ)).
There is a relationship between them: E(λ)=EP(λ)+Es(λ). Then, the spectral energy of the transmitted light from the depolarizing plate 10 is Ep(λ)=”””, Es(λ
, = E (2).

Here, if the combined transmittance of the P-polarized light of the condensing optical system 11 and the spectroscope 12 is SP(λ), S, and (λ), the detected value AR(λ) at the photomultiplier 23 is AR(λ1
=Ep(λ)·Sr(λ)+Es(λ)·Ss(λ). Therefore, from each of the above formulas, A(λ) is the amplifier 15
The value is stored as a reference value in the storage unit 24 via.

Next, the standard light source is removed, a light-emitting object or a reflective object, which is the object to be measured 8, is placed and measurements are made in the same manner.

Here, the spectral energy of the light emitted from the object to be measured 8 is E'(λ), and the detected value at the photomultiplier 23 is As(λ).
-1 prisoner, As(λ)−(SP(λ)+Ss(λth).

SP(λ) and Ss(λ) in this formula are constants determined by the transmittance of the entire optical system in the spectrophotometer = 1, but it is difficult to measure accurately, and It is an unstable constant because it also changes. Therefore, it is very difficult to obtain it directly from the above formula in terms of accuracy, but according to the present invention, it can be obtained accurately as follows. That is, the detected value at the photomultiplier 23 amplified by the amplifier 15 is:
It is divided by the reference value stored in the storage unit 24 via the calculation unit 25, and the spectral energy E of the standard light source is added to this value.
(λ) is multiplied by the spectral energy E of the light emitted from 8.
'(λ) can be found. Then, this E' (phantom A) is printed and displayed accurately and in a short time by the printer 2B as the spectral energy of the light emitted or reflected from the object to be measured 8. , accurate measurement is possible by switching the switching mirror 21 to the position shown by the solid line and performing pure observation.The position of the depolarization plate 10 is determined by the position of the object to be measured 8 and the spectrometer 12. Any position between the two is acceptable.

Effects of the Invention As described above, according to the present invention, the spectral characteristics of light emitted from a light emitting object or a reflecting object can be measured in a short time and with high precision.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the basic configuration of the present invention, and FIG. 3 is an explanatory diagram showing the configuration of a conventional technique. 8...Object to be measured 10...Depolarizing plate 11...Condensing optical system 12...Spectroscope 15...Amplifier 26...・・・・・・Printer (display part) description ♀ Hosho writing spontaneously> March 27, 1985 Mr. Manabu Shiga, Commissioner of the Patent Office ■, Indication of the case 1982 Patent Application No. 169670 2, Name of the invention Spectrophotometer 3, Relationship with the case of the person making the amendment Patent applicant address: 2-43-2-4 Hatagaya, Shibuya-ku, Tokyo, Agent 6, Detailed explanation of the invention in 1 of the specification to be amended 7. Contents of amendment (1) Page 3, line 10 of the specification: ``The amplifier 6 is the display part 7.
Connect with. The statement "Display unit 7 is connected to amplifier 6" is corrected. (2) The description "display section 9" on page 3, line 13 of the specification is corrected to read "r display section 7J." (3) The statement “The amplifier 15 is connected to the display unit 16” on page 3, lines 15 and 16 of the specification has been changed to “The display unit 16 is connected to the amplifier 1.
5 and connect.'' (4) The statement ``difficult and dangerous'' on page 11, line 13 of the specification is amended to ``difficult, but''.

Claims (3)

[Claims] (1) An optical system for condensing light emitted from an object to be measured, which is a light-emitting object or a reflective object, near the entrance slit of a spectrometer, and an optical system for separating and emitting the incident light from the condensing optical system. A light receiving element for detecting the amount of light emitted from the spectrometer, an amplifier for amplifying the output of the light receiving element, and a display section for displaying the output from the amplifier. In the spectrophotometer, a material having birefringence is used between the object to be measured and the entrance slit of the spectrometer to make the light emitted from the object to be measured unpolarized and enter the entrance slit of the spectrometer. A spectrophotometer characterized in that a depolarizing plate is disposed in which a plurality of wedge-shaped transparent plates are joined such that their crystal axes are sequentially shifted by 45 degrees. (2) The above-mentioned elimination plate is made by arranging two identical wedge-shaped crystal plates facing each other with their crystal axes shifted by 45 degrees, and
2. The spectrophotometer according to claim 1, wherein a transparent plate having a refractive index substantially the same as that of the crystal is interposed between two crystal plates. (3) The spectrophotometer according to claim 1, wherein the condensing optical system is equipped with a switching mirror that can be freely switched at each corresponding position during measurement or observation.