JPS63215923A - Auxiliary apparatus for spectrophotometer - Google Patents

Abstract

PURPOSE:To enable measurement at a desired angle of incidence without effect of a reflection mirror, by adjusting a measuring light so that after reflected with first and second reflection mirrors, it travels with the optical axis thereof passing through the center point of the surface of a sample on a sample base and further reflected with third and fourth reflection mirrors to move along the original optical axis. CONSTITUTION:When first and fourth reflection mirrors M1 and M4 inserted into a measuring optical path are positioned on an optical axis O1, a measuring light is changed in the optical path with the reflection mirror M1 and reflected with the second fourth reflection mirrors M2-M4 to return to the original optical axis O1 again. With such an arrangement, spectral reflection characteristic by reflection with all the reflection mirrors is determined. Then, a sample S is so arranged that the surface thereof reaches a position O of intersection between the optical axes O3 and O1 and the reflection mirrors M3 and M4 are replaced with reflection mirrors M3' and M4'. Consequently, the measuring light is made incident into the sample S at an angle theta of incidence to be reflected and further reflected with the reflection mirrors M3' and M4' to return to the original optical axis O1. Thus, comprehensive spectral reflection characteristic is measured from spectral reflection characteristic when light is incident into the sample S at an angle theta of incidence and that obtained by reflection from all the reflection mirrors.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an auxiliary device for spectroscopic measurements at oblique incidence in a spectrophotometric device.

[Conventional technology]

With the recent development of optoelectronics, various optical components have been produced, one of which is an interference filter made by depositing a multilayer film. The spectral characteristics of this interference filter can be measured using a spectrophotometer or the like. Furthermore, although it is possible to measure the spectral reflectance when the angle of incidence is not 0°, accurate measurement is difficult because the measurement optical path changes.

The reason for this is that if the optical path is returned to its original state using a reflector or the like, the reflectance of the reflector is affected, and the reflectance of the material is not purely measured.

As shown in FIG. 7, a reflector M+ is placed on the optical axis OI of the measurement light of the spectrophotometer to bend the optical path, and further reflectors Mz,
When measuring the spectral reflectance of a material by arranging Ml and reflecting the light back onto the optical axis of the measurement light, as shown in Figure 8, the light is reflected by the reflecting mirror MI. By placing the material S in the optical path, the measurement light is made incident on it at a constant angle of incidence, and the reflector island is moved to the position of the cover. The reflected light from S is returned onto the optical axis of the measurement light.

This causes the reflecting mirrors Ml, M2. Photometry can be performed while removing the influence of reflectance of Ml.

Assuming that the reflectance of each reflecting mirror is R1-&-R4, and the amount of incident light is 0, each reflecting mirror Mt, M21 in Fig. 7
The amount of light ID that enters the light receiver after being reflected by M4 is given by the following equation.

ID = Io・Rs ” &・R2 Also, since the spectrophotometer is generally a double bus type, in addition to the amount of received light mentioned above, it monitors the amount of light proportional to ■. Therefore, if the monitored light amount IM = R・E. The line-corrected values are as follows.

On the other hand, in the case of FIG. 7, if the reflectance of the material is Rs, the following formula is obtained.

I'D = Io・R1・R8'R2" R4I I
By taking the ratio of dM and 1'-, the reflectance of the material can be determined purely by I=Rs.

However, the angle of incidence on the material S is fixed depending on the positions of the reflecting mirrors Ms and Ml, making it impossible to measure at any arbitrary angle of incidence.

[Problem that the invention seeks to solve]

The problem to be solved by the present invention is that it is possible to measure the spectral reflection characteristics of a material using a spectrophotometer, and it is also possible to measure at any angle of incidence without the influence of the reflectance of a reflecting mirror. This provides an auxiliary device that can

[Means for solving problems]

In order to solve the above-mentioned problems, the auxiliary device in the spectrophotometric device of the present invention includes a first reflecting mirror arranged on the optical axis of the measurement light and for bending the optical path, and a light beam reflected by the first reflecting mirror. a second reflecting mirror disposed on the optical axis of the measurement light and movable along the optical axis and rotatable; a third reflecting mirror that reflects the reflected light from the second reflecting mirror; a fourth reflecting mirror disposed on the optical axis of the measuring light and reflecting the light from the third reflecting mirror in a direction returning to the original optical axis of the measuring light; By arranging the material on the optical axis, the measurement light is made incident on the material, and by changing the third reflecting mirror to another position and changing the fourth reflecting mirror, the measurement light reflected by the material can be reflected. The measurement light is sequentially reflected by a third reflecting mirror and a fourth reflecting mirror to return it to the original optical axis of the measurement light. In addition, by moving and rotating the second reflecting mirror along the optical axis of the light reflected by the first reflecting mirror, the light reflected by the second reflecting mirror can be moved to a different location with respect to the material. The third reflecting mirror is moved along the optical axis of the light reflected by this reflected light and rotated at the same time, so that the reflected light is reflected at a fourth reflected angle. The light is reflected by a mirror and directed toward the optical axis of the measurement light of the spectrophotometer. Therefore, the influence of the reflectance of each reflector was removed by spectrophotometry of the light reflected by each reflector and by spectrophotometry of the light reflected by each reflector using the reflected light obliquely incident on the material. Capable of spectrophotometry of materials. Moreover, the above-mentioned movement of the second reflecting mirror and the third reflecting mirror.

Rotation allows photometry at any angle of incidence.

FIG. 1 is a diagram showing the principle of the auxiliary device in the spectrophotometer of the present invention, where Ml is the optical axis 01 of the measurement light of the spectrophotometer.
The first reflecting mirror M2, which is arranged to be tilted upward, is arranged on the optical axis 0□ of the light that is reflected by the first reflecting mirror Ml and goes in a direction of, for example, 120° with respect to the optical axis OI. The second reflecting mirror, which is movable and further rotatable along 0□, is a third reflecting mirror located on the optical axis 03 of the light reflected by the second reflecting mirror M2, It is movable and rotatable along the optical axis 04 of the light reflected by this reflecting mirror. Further N
'L4 directs the light reflected by the third reflecting mirror group to the original optical axis 0.
! This is the fourth reflecting mirror for directing the direction.

Also, for S, align the reflective surface with the optical axis O7 in the document and further align the optical axis OI.
The center is located at the intersection of the optical axis 03 and the optical axis 03. When the material S is placed at this position, the third reflecting mirror M3 is changed to the position M3' and the fourth reflecting mirror M3 is moved to the position M3'.

Shooting Mirror Fox is switched to the W position. The third reflecting mirror and the fourth reflecting mirror are M3, Ms', M4 with respect to the optical axis O1.
Transform so that and le are symmetrical. Therefore, the measurement light is reflected by the first reflecting mirror Ml and directed toward the optical axis 02, reflected by the second reflecting mirror group, directed toward the optical axis 03, and incident on the material S at an incident angle θ and reflected. Ru. Thereafter, it is reflected by the reflecting mirror group' of the tube 3 and the fourth reflecting mirror group', and is directed toward the optical axis 0+ direction.

In this way, the first reflecting mirror M1. Second reflecting mirror M2゜3rd
An auxiliary device consisting of a fourth reflecting mirror M4 is inserted into the optical path of the measurement light of the spectrophotometer, and the first reflecting mirror M+ and the fourth reflecting mirror group are positioned on the optical axis 01. If so, the measurement light will be transmitted to the first reflecting mirror M.

The optical path is changed at the second reflecting mirror M2. Third reflective bell M
s, it is reflected by the fourth reflecting mirror group and returns to the original optical path 01 of the measurement light. As a result, the spectral reflection characteristics resulting from reflections from all the reflecting mirrors are determined.

Next, place the material S so that the material surface is on the optical axis O7 at the intersection of the optical axis 03 of this auxiliary device and the optical axis OI of the measurement light, and place the third reflecting mirror group and the fourth reflecting mirror group. M3', M respectively
, ', the measurement light is incident on the material surface S at an incident angle θ, is reflected, and is further reflected by the third reflecting mirror M3' and the fourth reflecting mirror group', and is returned to its original state. Optical axis O9
Return to As a result, the total spectral reflection characteristics of the spectral reflection characteristics when the light is incident on the material S at the incident angle θ and the spectral reflection characteristics due to reflections from all the reflecting mirrors are measured.

Here, the first to fourth reflecting mirrors MH, M2, M3',
M4' is the first to fourth reflecting mirrors M when the material S is not placed
Since it is exactly the same as M21MY2M4 and the reflection conditions are the same, it is possible to determine the spectral reflectance characteristics of the material with the influence of the reflecting mirror removed from the constant values on both sides.

That is, as in the conventional example described above, the reflecting mirror Mt = M2
, M, l, and At are R+, R2, Rs, respectively.
R4, the light intensity of the measurement light is 0, and the reflectance of the material is Rs, then the measurement light amount IB when the material is large and the measurement light amount IR when the material is placed are as follows.

IB = I. −R2・R2・R5・R4IR= Io
"R+"R2"R3@R3' R4■ Therefore, the pure reflectance of the material is determined by "/H8= Rs.

Similarly, with the material placed there, move the third and fourth reflecting mirrors to M3. The measured value IT at the position M4 is as follows, where Ts is the transmittance of the material.

IT=Io"R+ΦR2"rs"R3#R4
Therefore, the transmittance of the material can also be determined from Iq,=Ts.

Next, move the second reflecting mirror group along the optical axis 02 to
The optical axis 03' of the light reflected by the second reflecting mirror M2 placed at the A2 point is the sample by moving from the point to the A2 point and rotating around the point on the optical axis 0□. S
so that it passes through the center point 0 of the arrangement position. Furthermore, the third reflecting mirror group also has an optical axis of 0. along the optical axis 04 by moving it from point B1 to point B2 and simultaneously rotating it around the point on optical axis 04.
The light traveling along ' is reflected and directed to the fourth reflecting mirror ■. Furthermore, the light reflected by the fourth reflecting mirror group has an optical axis of 0.
Returned to 1.

On the other hand, by inserting the material S, moving the third reflecting mirror group to the position of point B3, and converting the fourth reflecting mirror to 'L', the second reflecting mirror M2 placed at point A2 The reflected light is incident on the material S at an incident angle θ2, and the reflected light is further transmitted to the third reflecting mirror M,', and the fourth mirror placed at the point B3.
The light is reflected by the reflective mirror layer of 2 and directed along the original measurement optical path 0+.

In this way, the angle of incidence θ on the material S is different.
The spectral reflectance of material S in 2 can be measured.

In this case as well, since the reflection is in the same state from the same reflector before inserting material S and when material S is inserted, the correct spectral reflectance of the material can be determined by completely removing the influence of the reflecting mirror. It will be done. In addition, the spectral transmittance can also be determined in the same manner.

As described above, the second reflecting mirror M2 is moved along the optical axis 02, and this second reflecting mirror M2 is also rotated so that the reflected light is directed toward the center point O of the material S, and the By moving and rotating the third reflecting mirror M3 along the optical axis 04, the measurement light is reflected by the fourth reflecting mirror and then proceeds in the direction of the optical axis O8. It is possible to measure the spectral reflectance of the material at the incident angle.

FIG. 2 shows an example of a commonly used spectrophotometer, in which broadband wavelength distribution light from a light source W is transmitted through a concave reflecting mirror M.
R, and enters the prism P through the chopper CM, slit St, l'roidal mirror MR2, and concave mirror MR3, and enters the spectrometer G or G2 with low resolution. The light diffracted by the diffraction grating G+ or G2 and separated into high-resolution spectra is reflected again by the concave mirror MR6, and is reflected by the slit S3. Cylindrical mirror MR7 through rotating mirror M Rg
The beam is time-divided into reference light and measurement light. Reference light is plane mirror M
RQ 9MR+o, MR+□.

It passes through the toroidal mirror MR+4 and is detected by the detector PMT. On the other hand, the measurement light is a plane mirror MR++, MR13,
) It passes through the loidal mirror MR+5 and is detected by the detector PMT. The reference light and measurement light are processed in a time-sharing manner, and furthermore, by sampling processing synchronized with the cycle of the chopper CH, processing is performed with a high S/N ratio, and without being affected by changes in the light intensity of the light source W by comparison with the reference light. Ru.

The auxiliary device 41 of the present invention based on the principle shown in FIG.
, is placed on the optical axis 01 of the measurement light.

Next, the rotation of the second reflecting mirror island when the second reflecting mirror M is moved along the optical axis 02 in order to change the angle of incidence on the specimen in the apparatus of the present invention will be described.

In FIG. 3, when the light along the optical axis OI is reflected by the first reflecting mirror M and travels to the optical axis 02, the angle formed by the optical axis o1 and the optical axis 02 is γ. Also, when the light reflected by the second reflecting mirror M2 passes through the center point 0 of the material S, the second
The inclination of the reflecting mirror M2 from the direction parallel to the optical axis 01 is φ,
When the angle of incidence on the material is θ, the following equation (1) holds true.

φ=7(γ10−90°) (1) In FIG. 1, γ=60°, so in that case, equation (2) is obtained.

φ=7(θ-30°) (2) Therefore, the second reflecting mirror ■ is changed by 7 of the amount of change in the incident angle θ by moving the second reflecting mirror M2 along the optical axis O7. Just rotate it. At this time, the third reflecting mirror M3 is
The second reflecting mirror M2 may be displaced symmetrically with respect to the center point O of the material S as a point of symmetry.

〔Example〕

Next, as an example of the present invention, a specific structure of the auxiliary device of the present invention will be explained. FIG. 4 is a plan view of an embodiment of the present invention;
FIG. 5 is a sectional view of the same embodiment.

In these figures, 1 is a pace for arranging each part of the device, and 2 is a plate fixed on a base 1, which directs the first reflecting mirror MI in a direction tilted by 120° (γ = 60°).
a first holding frame held so as to face the direction of
1 is a first guide rail arranged to match the optical axis 02 of the light reflected by the first reflecting mirror M+, 4 is a second holding frame that holds the second reflecting mirror, and 5 is a holding frame. A rotating table having a rotating shaft 5a fixed to the lower surface of the frame 4; 6 a symmetrical lever mounted on the base 1 so as to be rotatable about the rotating shaft 6a located at the center point O of the material S; 7 a symmetrical lever on one side; A sliding groove 6b is formed in the symmetrical lever 6 by having an end rotatably attached around the rotating shaft 5a of the rotary table 5 and a pin 7aK at the other end.
8 is a gear fixed to the rotating shaft 5a of the rotary table 50; 9 is another gear that meshes with the gear 8; 10 is configured to rotate together with the gear 9; The attached gear meshes with teeth formed at the tip of the angle holding lever 7. Further, 11 is a document holding table, 12 is a gear fixed to the rotating shaft 6a of the symmetrical lever 60, 13 is a gear that meshes with the gear 12, 1
4 is a gear that meshes with gear 13, 15 is a symmetrical lever 6
Another symmetrical lever 16, which is rotatably held around the rotation axis 6a of the symmetrical lever 15, is a gear that rotates together with the symmetrical lever 15 and meshes with the gear 14.

17 is a second guide rail arranged in a position symmetrical to the first guide rail with respect to the center point O of the material S; 18 is a holding table for holding the third reflective island; 19 is a rotating table; 20
is an angle holding lever, and 21, 22, and 23 are gears, which have substantially the same configuration as that for the second reflecting mirror M2.

24 is a third guide rail that is placed in plane symmetry with respect to both the first guide rail 3 and the second guide rail 17, and 25 is a third reflecting mirror M3 (M3' in FIG. 1).
), 26 is a rotary table, 27 is an angle holding lever, and 28, 29, 30 are gears, which are moved by the symmetrical lever 15.
The configuration is substantially the same as that in .

Note that 31 is a holding stand for holding t to the fourth reflecting mirror,
The structure allows the fourth reflecting mirror to be switched between the shield position and the M4' position.

In the embodiment with the above structure, for example, if the second reflecting mirror M2 and the third reflecting mirror hh are both set parallel to the optical axis 01 as shown in the figure, the incident angle θ(
It is possible to measure the spectral reflectance of the material at θ=30°).

If the symmetrical lever 6 is rotated around the rotating shaft 6a, the first holding table 4 holding the second reflecting mirror M2 moves along the guide rail 3. At this time, the angle holding lever 7 also moves, thereby rotating the gear 10, rotating the rotary table 5 via the gears 8 and 9, and rotating the second reflecting mirror together with the holding frame 4.

At this time, the amount of change in the angle of incidence T by gear 8.9.10
If the rotary table 5 is rotated by the amount, the second reflecting mirror M2
The measurement light reflected by the object always passes through the center point 0 of the material S.

Since the third reflector island also has substantially the same configuration, the rotation of the symmetry lever 6 causes the first third reflector island to become symmetrical to the second reflector M2 with respect to the center point of the material S by the same action. move and rotate.

This rotation of the symmetrical lever 6 causes the gear 12 to rotate, which causes the symmetrical lever 15 to move in the opposite direction via the gears 13 and 14 so that it always moves in plane symmetry with respect to the symmetrical lever 6 with respect to the optical axis O1. do.

By the movement of this symmetry lever 15, the third holding frame 25 that holds the third reflecting mirror M3 is moved to be plane symmetrical with the second reflecting mirror M2 by the same action as the first holding frame 4, etc. do.

As described above, even if the angle of incidence on the material S is changed from θ to θ' by rotating the symmetrical lever 6, each reflector moves exactly the same as the principle based on Fig. Measurement becomes possible.

Since this embodiment has the structure described above, the measurement light is first reflected by the first reflecting mirror M+ r second reflecting mirror section by the mounting position adjustment mechanism provided on each reflecting mirror holding frame. After that, the optical axis passes through the center point of the material surface when the material is placed on the material stand, and is further reflected by the third reflecting mirror hole and the fourth reflecting mirror M4, and then returns to the original optical axis 02. If the beam is adjusted so as to move along the same direction, the spectral transmittance and spectral reflectance of the specimen at the incident angle θ to the specimen at that time can be measured as described in the above-mentioned principle.

Furthermore, by rotating the symmetrical lever 6, the angle of incidence on the material can be changed, and in that case, the angle of incidence on the material can be changed by rotating the first reflecting mirror M+r, the second reflecting mirror Mt, the third reflecting mirror M3, or the fourth reflecting mirror M+r, respectively. First reflecting mirror M+ + second reflecting mirror M2, material S,
The light is sequentially reflected by the third reflecting mirror M3' and the fourth reflecting mirror M3' and can always be returned to the original optical axis 0+, making it possible to perform the measurement described in the principle.

FIG. 6 shows another example of the arrangement of the reflecting mirrors, etc. of the auxiliary device of the present invention. A non-symmetrical arrangement as in the example shown in this figure is also possible, and completely similar measurements can be made by moving and rotating the second and third reflecting mirrors, respectively.

〔Effect of the invention〕

Since the present invention has the above-described configuration, it is possible to perform spectroscopic measurements by oblique incidence without being influenced by a reflecting mirror, and also to perform measurements at any angle of incidence.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the auxiliary device of the present invention, and FIG. 2 is a diagram showing an example of a spectrophotometer using the auxiliary device of the present invention.
Fig. 3 is a diagram showing the relationship between movement and rotation of the second reflecting mirror used in the auxiliary device of the present invention, Fig. 4 is a plan view of an embodiment of the invention, and Fig. 5 is a cross section of the embodiment. 6 are cross-sectional views of other embodiments, and FIGS. 7 and 8 are diagrams showing an auxiliary optical system in the case of conventional spectral reflection characteristic measurement using oblique incidence. Ml...first reflector, M2...second reflector, intestine.

Claims (1)

[Claims] An auxiliary device that is inserted into the measurement optical path of a spectrophotometer to perform measurements at an oblique angle of incidence on a material, and when the auxiliary device is inserted, it is located on the measurement optical path and emits a different measurement light. a first reflecting mirror that directs the measuring light toward the direction; a second reflecting mirror and a third reflecting mirror that sequentially reflect the measurement light reflected by the first reflecting mirror; a fourth reflecting mirror that reflects the measured measurement light and returns it to the measurement optical path of the spectrophotometric device; and a document table that is placed between the second reflecting mirror and the third reflecting mirror and enables the installation of materials. The second reflecting mirror is movable on the optical axis of the measurement light reflected by the first reflecting mirror, and simultaneously moves the center of the material surface to be placed on the material table to the second reflecting mirror. The second reflecting mirror is rotated so that the optical axis of the measurement light reflected by the reflecting mirror passes through, and the third reflecting mirror always directs the light from the second reflecting mirror to the fourth reflecting mirror. When the material is placed on the material table and the reflection characteristics are measured, the material is moved on the optical axis of the measurement light reflected by the third reflecting mirror and rotated. A third reflecting mirror is placed at another position in order to reflect the reflected light and direct it to a fourth reflecting mirror, and at the same time, the third reflecting mirror is moved on the optical axis of the light reflected by the third reflecting mirror and rotated. An auxiliary device in a spectrophotometer that can be moved.