JPH0710266Y2 - Automatic optical fine adjustment device for multiple spectrometers - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a device for automatically performing optical fine adjustment of a multi-spectrometer in which a plurality of spectroscopes are connected in series.

[Prior art]

In the measurement of Raman scattered light, the Raman scattered light intensity is much weaker than the Rayleigh scattered light intensity, and in order to remove stray light, a multiple spectroscope with two or more spectroscopes connected in series is used. There is. However, if the spectroscopes are displaced due to mechanical shock during movement, the Raman spectrum cannot be obtained. In particular, in high-resolution measurement, the slit width is narrowed to about 10 μm, and therefore, there is a case where the spectroscopes are displaced due to thermal expansion due to a change in ambient temperature and desired performance cannot be obtained. Therefore, conventionally, the position of the optical element of the spectroscope has been finely adjusted before the measurement.

[Problems to be solved by the device]

However, the adjustment is not easy and requires skill, and the adjustment takes about one hour. In view of such problems, an object of the present invention is to provide an automatic optical fine adjustment device capable of automatically performing optical fine adjustment of a multiple spectrometer in a short time.

[Means for solving problems and their effects]

In order to achieve this object, in the automatic optical fine adjustment device for a multiple spectrometer according to the present invention, a plurality of spectrometers (12, 14, 15) are provided.
Diffraction grating (122, 1
42, 152) wave number scanning device (126) that drives the rotation
A minute rotation driving device (136, 146, 156) for minutely rotating the imaging mirror (134, 144, 154) of the multiple spectrometer, and slits (121, 128, 141, 151) of the multiple spectrometer. , 158) opening width switching drive device (126, 129, 14).
5, 155, 159) and a control device (19). This control device comprises a photodetector (16) for detecting the intensity of light emitted from the spectroscope (15) at the final stage in the first step, and the slit of the spectroscope (12) at the first stage in the first step. Narrowing the opening width of (121, 128), all other slits (141, 151, 158)
The output of the photodetector is maximized by slightly rotating the diffraction grating in a state where the opening width of the slit is widened, and in the second step, the opening of the slit of the next stage is narrowed and focused on the slit side. The imaging mirror is slightly rotated to maximize the output of the photodetector, and the second step is repeated to the final stage. According to this device, it is possible to automatically perform optical fine adjustment of the multiple spectrometer in a short time. If the photodetector (16) is dedicated to the optical fine adjustment and the drive device (17) for moving the photodetector into and out of the optical path at the time of the optical fine adjustment is provided, the optical detector is erroneously adjusted during the optical fine adjustment. It is possible to prevent the detector from being damaged by the strong light entering the high sensitivity detector for measurement. The minute rotation is, for example, as shown in FIG. 3, rotated by an angle θ _m in one direction (A) and rotated by an angle 2θ _{m in the} other direction while maximizing the output of the photodetector (16). Find _o (B), rotate the angle 2θ _{m in the} one direction (C),
Further, the angle θ _{o is} rotated in the other direction (D). With such a slight rotation, the rotation direction (B) when finding the rotation angle θ _o that maximizes the output of the photodetector (16)
Since the final rotation direction (D) is the same, the adjustment becomes accurate.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 shows multiple units equipped with automatic optical fine adjustment device (triple)
3 shows a spectroscope. The light source 10 has a line spectrum such as a laser or a mercury lamp, and the emitted light transmits / scatters through the sample 11, and approximately 90 ° scattered light is collected by an optical system (not shown) to form a first spectroscope. The light is incident on twelve variable slits 121. This incident light is transmitted through the first spectroscope 12, the dispersion image inverting optical system 13, and the second spectroscope 14.
Then, the light passes through the third spectroscope 15 and is detected by a photodetector 16 having an imaging optical element. The photodetector 16 is used only at the time of fine adjustment of the optical, and the photodetector advancing / retreating drive device 17 allows the photodetector 16 to advance / retreat in the optical path. During normal measurement, a high-sensitivity multichannel photodetector or a photomultiplier tube (not shown) equipped with an imaging optical element is used instead of the photodetector 16. The purpose of using the dedicated photodetector 16 at the time of adjustment is to prevent damage to the high-sensitivity detector due to accidental strong light incident on the detector. The output of the photodetector 16 is digitized by the A / D converter 18,
It is supplied to the control device 19. The first spectroscope 12 collimates the light incident on the variable slit 121 by the collimator mirror 123, projects the collimated light on the diffraction grating 122, collects the dispersed light diffracted by the diffraction grating 122 on the imaging mirror 124, and changes the light. An image is formed at the position of the slit 128. The dispersed image inverting optical system 13 is configured to bend the emitted light from the first spectroscope 12 by the plane mirrors 132 and 133 to enter the image forming mirror 134, and further bend it by the plane mirrors 137 and 138 to invert the dispersed image. It has become. The second spectroscope 14 is one of the emitted lights of the dispersed image inverting optical system 13.
Only those that have passed through the variable slit 141 arranged at the image forming position are collimated by the collimator mirror 143 and projected by the diffraction grating 142,
The configuration is such that dispersed light diffracted by the diffraction grating 142 is condensed by an image forming mirror 144 and is bent by a plane mirror 147 to form an image. Similarly, the third spectroscope 15 is
Only the light passing through the variable slit 151 arranged at the image forming position is bent by the plane mirror 157A, collimated by the collimating mirror 153 and projected on the diffraction grating 152, and the dispersed light diffracted by the diffraction grating 152 is formed by the image forming mirror 154. The light is condensed, an image is formed at the position of the variable slit 158, the image is bent by the plane mirror 157B, and an image is formed on the light receiving surface of the photodetector 16 or the measurement detector (not shown). Each of the variable slits 121, 128, 141, 151 and 158 is provided with an opening width switching driving device 125, 129, 145, 155 and 159 so that the opening has a wide width, for example, a narrow width of about 5 mm, for example, 1 mm.
It can be switched to about 0 μm. Further, the diffraction gratings 122, 142 and 152 are configured to be mechanically interlocked with each other, and are rotationally driven by the wave number scanning device 126 so that the wave numbers can be scanned. Further, the image forming mirrors 134, 144 and 154 can be slightly rotated right and left by fine rotation drive devices 136, 146 and 156, respectively. The minute rotation drive device 136 includes, for example, a worm wheel that rotationally drives the imaging mirror 134, a worm that meshes with the worm wheel, and a pulse motor whose output shaft is connected to the worm. As for the structure of the minute rotation drive devices 146 and 156, the minute rotation drive device 13
Similar to 6. Wave number scanning device 126, aperture width switching drive device 125, 129, 145,
The control device 19 controls the 155, the minute rotation drive devices 136, 146, 156 and the photodetector advance / retreat drive device 17. Next, the automatic optical fine adjustment procedure by the controller 19 will be described with reference to FIG. The diffraction grating 122 and the imaging mirrors 134 and 14
The rotation angles of 4 and 154 are preliminarily roughly adjusted. (50) The opening widths of the variable slits 121 and 128 are switched to the narrower ones, and the opening widths of the variable slits 141 and 151 are switched to the wider one. Then, the diffraction grating 122 is slightly rotated left and right to maximize the output of the photodetector 16. That is, finding as shown in Figure 3, in one direction at an angle theta _m Rotate (A), the rotation angle theta _o the output becomes maximum light detector 16 while the angle 2 [Theta] _m rotating in the other direction (opposite direction) (B), rotate by an angle 2θ _{m in the} one direction (C), further rotate by an angle θ _{o in the} other direction, and stop (D). Angle θ _m
Is an aperture width of the variable slit 141 with respect to the optical path length from the imaging mirror 124 to the variable slit 128, for example, a minute angle of about 10/5 × 10 ⁵ = 2 × 10 ⁻⁵ radian. (51) In the same manner as above, the imaging mirror is switched so that the opening width of the variable slit 141 is switched to a narrower one so that the output of the photodetector 16 becomes maximum.
Rotate 134 slightly left and right. (52) Switch the aperture width of the variable slit 151 to the narrower one so that the output of the photodetector 16 becomes maximum, and the image forming mirror is formed in the same manner as above.
Slightly rotate left and right to 144. (53) In order to maximize the output of the photodetector 16 by switching the aperture width of the variable slit 158 to the narrower one, the same image forming mirror as above.
Slightly rotate 154 left and right. Such an automatic optical fine adjustment device brings the multiple spectroscope into the optimum state. The conventional manual adjustment takes about 1 hour, but the apparatus of this embodiment enables automatic adjustment in about 4 to 5 minutes.

[Brief description of drawings]

1 to 3 relate to an embodiment of an automatic optical fine adjustment device for a multiple spectrometer according to the present invention, and FIG. 1 is a configuration diagram of a multiple spectrometer equipped with the automatic optical fine adjustment device, FIG. 2 is a flowchart showing an automatic optical fine adjustment procedure by the control device, and FIG. 3 is a diagram showing the output of the photodetector and the minute rotation order of the diffraction grating or the imaging mirror during the optical fine adjustment. In the figure, 10 is a light source 11 is a sample 12 is a first spectroscope 13, 13 is a dispersion image inverting optical system, 14 is a second spectroscope, 15 is a third spectroscope, 16 is a photodetector, 17 is a photodetector, and 18 is a forward / backward drive device. The / D converter 19 is a control device 121, 128, 141, 151, 158 is a variable slit 122, 142, 152 is a diffraction grating 123, 143, 153 is a collimating mirror 124, 134, 144, 154 is an imaging mirror 125, 129. , 145, 155, 159 are aperture width switching drive devices 126 are wave number scanning devices 136, 146, 156 are minute rotation drive devices 132, 133, 137, 138, 147, 157A, 157B are plane mirrors.

Claims (3)

[Scope of utility model registration request] 1. A wave number scanning device (126) for rotationally driving a dispersion diffraction grating (122, 142, 152) of a multiple spectrometer in which a plurality of spectrometers (12, 14, 15) are connected in series. A minute rotation driving device (136, 146, 156) for minutely rotating the imaging mirror (134, 144, 154) of the multiple spectrometer, and slits (121, 128, 141, 151) of the multiple spectrometer. , 158)
Aperture width switching drive (125, 12
9, 145, 155, 159), a photodetector (16) for detecting the intensity of light emitted from the spectroscope (15) at the final stage, and the slit of the spectroscope (12) at the first stage in the first step. The output of the photodetector is maximized by slightly rotating the diffraction grating with the aperture widths of (121, 128) narrowed and the aperture widths of all other slits (141, 151, 158) widened. Let
In the second step, the aperture of the slit in the next stage is narrowed and the focusing mirror for focusing on the slit side is slightly rotated to maximize the output of the photodetector, and the second step is repeated to the final stage. A control device (19), and an automatic optical fine adjustment device for a multiple spectroscope, comprising: 2. The photodetector (16) is dedicated to optical fine adjustment, and is provided with a drive device (17) for moving the photodetector into and out of an optical path during the optical fine adjustment. The device according to claim 1. Wherein the micro rotary finds the rotational theta _o the output of the one direction angle theta _m Rotate (A), the photodetector while the angle 2 [Theta] _m rotating in the other direction (16) is maximized ( The device according to claim 1 or 2, wherein B) is rotated in the one direction by an angle 2θ _m (C), and further rotated in the other direction by an angle θ _o (D).