JPH04152246A - Microscopic infrared spectro-photometer of fourier transform type - Google Patents

Abstract

PURPOSE:To shorten the measuring time and provide precise measurability by diverging a light flux from a specimen into two fragments by a beam splitter, synthesizing an image from focused images on their image points, and thereby performing checking of the part to be measured without requiring movement of a shield mask. CONSTITUTION:A beam splitter 15 is furnished behind an objective mirror 3 to form two divergent light paths, and specify shield masks 10, 11 are provided only on one of the light paths at its image point. The beams of light on the two divergent light paths are monitored by respective cameras 20, 21 in positions behind their image points. Signals given by these TV cameras 20, 21 are fed to an image processing device 22, and the focused images at the image points are synthesized in a screen to serve monitoring. According to this constitution. the position relationship between parts to be measured over the whole specimen 2 can be made clear without requiring movement of the shield masks 10, 11, and change of the part measured be made easily, which should shorten the measuring time greatly and also enhance the measuring accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a microscopic Fourier transform infrared spectrophotometer equipped with an infrared microscope.

[Conventional technology]

FIG. 3 shows a conventional general microscopic spectrometer, in which light f! Irradiate sample 2 with visible light from 1',
The transmitted light is collected by an objective mirror 3 to form an enlarged image on an image plane 4. Furthermore, the light from this image plane 4 is enlarged and imaged through a relay lens 5, and then focused on the image plane 4 by an eyepiece lens 6.
Observe.

On the other hand, when performing spectroscopic measurements, visible light is switched to infrared light, and an optical path switching mirror 7 is interposed between the image plane 4 and the relay lens 5 to transmit the infrared light to the relay optical system 8. After that, a spectroscopic spectrum is obtained by the detector 9 and analyzed.

For example, if you want to measure the spectrum of only the measurement target site A in the sample 2 as shown in FIG. 4(a),
As shown in FIG. 3, a mask 10.11 is installed on the image plane 4 to block light beams from areas other than the area to be measured, and only the light beams from the area to be measured are separated to obtain their spectra.

In other words, as shown in FIG. 4(b), a 1-shield mask 10.11 is formed on the image plane 4 by a rectangular slit in which each side is formed into a knife shape and the slit length can be changed arbitrarily.
is installed, the slit length is kept variable so as to block the light flux from σ parts B and C other than the measurement target part A, and to obtain the maximum light flux from the measurement target part A, and the measurement is performed.

[Problem to be solved by the invention]

However, if the measurement target is limited using the above method, the fourth
As shown in Figure (c), only part A is observed through the shielding mask 10.11, and the other parts B and C are shielded, so the positional relationship of part A in the entire image of sample 2 cannot be reconfirmed by visual observation. Furthermore, as the measurement object becomes smaller, or as the overall image becomes more complex such as a semiconductor chip or a biological cell tissue, it is extremely important to understand the positional relationship of the measurement object. 11 is very difficult.

Therefore, in order to reconfirm the positional relationship of the parts to be measured, it is necessary to temporarily remove the shielding masks 10 and II or move the slits.

Then, to remeasure, the positions of the shielding masks 1o and 11,
It is extremely difficult to reproduce the slit length with high precision.
This in turn leads to a decrease in measurement accuracy.

The present invention has been made with the above-mentioned considerations in mind, and its purpose is to be able to confirm the position of the measurement site without moving the shielding mask, to significantly shorten the time required for measurement, and to achieve high An object of the present invention is to provide a microscopic Fourier transform infrared spectrophotometer that enables accurate measurements.

[Means to solve the problem]

In order to achieve the above object, the microscopic Fourier transform infrared spectrophotometer according to the present invention is provided with a beam splitter behind the objective mirror to form two branched optical paths, and only one branched optical path has an image point. In addition to providing a predetermined mask, each light is monitored by an individual television camera behind each image point in both the branched optical paths, and the signals from each television camera are input to an image processing device, and each The feature is that the combined image at the image point can be observed as a composite image on the same screen.

[Effect]

According to the characteristic configuration described above, the light flux from the sample is split into two by a beam splitter, one is passed through the optical path side with a mask, and the other is passed through the optical path without a mask, and each beam is monitored by a separate television camera. Since the image processing device synthesizes the combined images at each image point, the positional relationship of the measurement target area in the entire sample becomes clear without moving the shielding mask, and the measurement target area can be easily changed. It is possible to dramatically shorten the measurement time and improve measurement accuracy compared to the conventional method.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

1 and 2 show an example of the configuration of a microscopic Fourier transform infrared spectrophotometer according to the present invention, and in these figures, the same reference numerals as shown in FIGS. 3 and 4 indicate the same thing or Show equivalent.

First, the visible light from the light lff11' is transferred to the mirror 12.13.
The sample 112 placed on the sample stage 2' is irradiated via the condenser mirror 14. Light such as fluorescence or phosphorescence excited by the light transmitted through the sample 2 or by the irradiation light is split by the beam splitter J5 via the objective mirror 3 into light that passes through two branched optical paths a and b. The light passing through the optical path a is reflected by the mirror 1G and forms an image at the image point 4a of the objective mirror 3. At this image point 4a, a shielding mask 10.11 consisting of, for example, a rectangular slit, each side of which is formed into a knife edge and whose slit length can be arbitrarily changed, is installed to shield light from areas other than the part to be measured. The shielding mask 10.11 is set so that only the light from the measurement target region inside passes through the shielding mask 10.11 (see FIGS. 4(b) and 4(c)). Note that a circular pinball may be used as the shielding means.

On the other hand, the light passing through the other optical path branched by the beam splitter 5 passes through the mirror 17 and forms an image at the image point 4b of the objective mirror 3, similar to the optical path a. Note that the above-mentioned shielding mask 0.11 etc. is not placed at this image point 4b at all.

After that, the shielding mass 10 installed at the image point 4a of the optical path a
．． The light passing through the optical path 11 is reflected by the mirrors 18 and 19, and then the image of the measurement target site at the image point 4a is monitored by the television camera 20, and the light passing through the image point 4b of the optical path is reflected by the television camera 20. 21 monitors the sample image at the image point 4b. And TV camera 20.
The signals from 21 are input to the image processing device 22, the respective signals are combined, and the resultant image is displayed on the screen of the television monitor 23 as a composite image of the image at the image point 4a and the image at the image point 4b.

Therefore, when observing this composite image, the shielding mask 10.
The part to be measured that is not shielded by the shielding mask 10.11 has higher brightness than the part that is shielded by the shielding mask 10.11 because the images of the image points 4a and 4b are combined.
You can confirm the setting position of the shielding mask 10.11 in . Moreover, since images of areas other than the measurement target parts can be confirmed on the same screen, the positional relationship of the measurement target parts in the sample 2 becomes clear.

After confirming the position of the measurement target site using the above method, in order to measure the spectral characteristics and intensity of the measurement target site using infrared light, as shown in FIG. 2, move the mirror 12 and,
A total reflection mirror 24 is installed in place of the beam splitter 15.

That is, the infrared light emitted from the light source 1 is passed through an interferometer 25 consisting of, for example, a two-beam interferometer, and energy intensity modulation is applied to each wavelength.
The sample 2 is irradiated through the condenser mirror 14, and the transmitted light is reflected by the total reflection mirror 24 through the objective mirror 3 onto the optical path a, and is imaged at the image point 4a of the objective mirror 3.

Since a shielding mask 10.11 is set in advance at the image point 4a using visible light so as to transmit only the light beam from the measurement target site, infrared light from other than the measurement target site is blocked. Next, the mirror 18 is moved, and the infrared light from the measurement target site is introduced into the relay optical system 8 by the mirror 28 . Since the infrared light is subjected to energy key modulation with a different frequency for each wavelength by the interferometer 25, the infrared light from the measurement target site is directly detected by the detector 9, and a spectroscopic spectrum is obtained by frequency analysis. .

In the above embodiment, a transmission-type microscopic Fourier transform infrared spectrophotometer was explained, but when measuring with a reflection-type, as shown in FIG. 29. The sample 2 may be irradiated with light through 29.30, and the measurement may be performed in the same manner using the reflected light.

[Effects of the Invention] As explained above, according to the present invention, the beam splitter splits the light beam from the sample into two, and passes one into the optical path provided with the mask and the other into the optical path without the mask. After the light is monitored by individual TV cameras, the combined images at each image point are synthesized by an image processing device, so the positional relationship of the measurement target part in the entire sample is clear without moving the shielding mask, making measurement easy. Since the target area can be changed, it has become possible to dramatically shorten measurement time and improve measurement accuracy compared to conventional methods.

[Brief explanation of drawings]

FIGS. 1 and 2 show an embodiment of the present invention, in which FIG. 1 is an optical layout diagram for confirming the position of a region to be measured, and FIG. 2 is an optical layout diagram for infrared spectrometry. 3 and 4 show conventional examples, FIG. 3 is a configuration diagram of a conventional microspectroscopic measurement device, and FIG. 4 is a plan view for explaining a method of shielding a non-measurement target region with a shielding mask. . 1.1'-light source, 2-sample, 31 objective mirror, 4a4b-image point, 10.11-shielding mask, 15-beam splinter, 20.21-television camera, 22-[i image processing device. Applicant: Horiba Ltd. Agent: Patent Attorney: Hideo Fujimoto

Claims (1)

[Claims] In a micro-Fourier transform infrared spectrophotometer that irradiates a sample with light from a light source and spectrally measures the reflected or transmitted light from the sample through an objective mirror, a beam splitter is provided behind the objective mirror, and two forming two branch optical paths,
A predetermined mask is provided at the image point on only one of the branched optical paths, and each light is monitored by an individual television camera behind each image point in both branched optical paths, and the signals from each television camera are converted into images. input into the processing device,
A microscopic Fourier transform infrared spectrophotometer characterized in that it is configured so that a combined image at each image point can be observed as a composite image on the same screen.