JPH0426812A - Polarization observing device - Google Patents

Abstract

PURPOSE:To obtain the polarization observing device which is superior in detection sensitivity in the observation of sharp colors to the conventional polarization observing device by using a polarizer and analyzer which are parallel Nicols and a phase element which generates the retardation of a half wavelength. CONSTITUTION:This device consists of a white light source 1, the polarizer 2 which polarizes the light from the white light source to linearly polarized light and irradiates a specimen 3 with this light, the phase element 7 which generates the prescribed wavelength retardation in the light from the specimen 3, and the analyzer 5 which observes the polarization state of the light past the phase element 7. The polarizer 2 and the analyzer 5 are approximately the parallel Nicols and the phase element is, for example, the halfwave plate which generates the retardation of the half wavelength. The sharp color observation having the detection sensitivity twice higher than heretofore is executed in this way.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a polarized light observation device.

[Conventional technology]

The general configuration of an optical system for performing sensitive color observation in this type of conventional polarized light observation device includes a white light source 1 and a linearly polarized light from the white light source 1, as shown in FIG. a polarizer 2 for irradiating the sample 3 with light from the sample 3; a single-wavelength plate 4 for producing one-wavelength retardation in the light from the sample 3; and a single-wavelength plate 4 for observing the polarization state of the light that has passed through the wavelength plate 4. , the polarizer 2 and a crossed nicol analyzer 5.

Then, the retardation generated by the sample 3 is R1, and the retardation generated by the wavelength plate 4 is λ. Then, the spectral intensity I of the light passing through the analyzer 5 is
(λ) is approximately ■ (λ)=sin” (λ.

+ R) -- (1) λ However, λ can be expressed in terms of wavelength. Normally - the wavelength plate 4 is λ. z530nm, and if it is RzO, λ;53 as shown by the dotted line in Figure 7.
The minimum value is 0 at 0 nm, and the color appears bright pink to the observer's eyes 6. Also, I (λ) has a minimum value of 0 in the visible region.
The wavelength λ, which takes λ, is λ,=λ. 10R...(2), and λ□ changes depending on the value of R, but λ□2530
In the vicinity of nm, the human eye 6 is most sensitive to color differences with respect to changes in λ, and therefore colors in the vicinity of 53 Onm relative to λ are generally called sensitive colors.

Therefore, using the above conventional example, the retardation generated by the specimen 3 can be detected based on the difference in color.

[Problem to be solved by the invention]

However, if R is very small, the change in color may be too small to be detected.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a polarized light observation device that has better detection sensitivity for R in sensitive color observation than conventional polarized light observation devices.

[Means and effects for solving the problem] As shown in FIG. 1, the optical system of the polarization observation device according to the present invention includes a white light source 1 and a linearly polarized light from the white light source that is irradiated onto a specimen 3. A phase element 7 that causes retardation of a predetermined wavelength in the light from the sample 3, and an analyzer 5 that observes the polarization state of the light that has passed through the phase element 7. The polarized light observation device is characterized in that the polarizer 2 and the analyzer 5 are substantially rose Nicols, and the phase element 7 is a device that produces half-wavelength retardation, for example, a half-wave plate.

That is, according to the polarized light observation apparatus according to the present invention, the spectral intensity I (λ) of the light that has passed through the analyzer 5 is equal to the retardation generated by the phase element 7 (half-wave plate, etc.). /2, it can be expressed approximately. A half-wave plate is usually λ. In the case of Rho, I (λ) takes a minimum value of 0 at λz530 nm, as shown by the solid line in FIG. 7, and the spectral characteristics are very similar to the conventional spectral characteristics.

However, the wavelength λ where I (λ) takes the minimum value 0 in the visible region
, is λ,=λ. +2R...(4), and the change in λ2 due to the value of R is equal to 2 of the conventional spectral characteristics.
It will be doubled. Therefore, according to the present invention, it is possible to perform sensitive color observation in which the R detection sensitivity is twice that of the conventional method.

〔Example〕

Hereinafter, the present invention will be described in detail based on the illustrated embodiments.

FIG. 2 shows an optical system of a polarizing microscope which is a first embodiment of a polarizing observation device according to the present invention, in which a white light source 1
A polarizing plate 2 is arranged between the condenser lens 8 and the condenser lens 8.
A rotatable analyzer is arranged between the objective lens 9 and the eyepiece 10, and a half-wave plate 11 that can be inserted and removed is further arranged between the objective lens 9 and the analyzer 5.

Since this embodiment is configured as described above, normal polarized light observation can be performed by removing the half-wave plate 11 from the optical path and making the analyzer 5 and the polarizer 2 cross nicols.
The bisection wave plate 11 is placed in the optical path, and the analyzer 5 is placed in the polarizer 2.
By setting it to paraNicol, sensitive color observation according to the present invention can be performed.

In this embodiment, a half-wave plate 11, that is, a phase element that generates half-wavelength retardation, is used for sensitive color observation. Twice as sensitive color observation can be performed.

In the above embodiment, instead of the half-wave plate 11, as shown in FIG. If the analyzer 5 is fixed to the polarizer 2 in a crossed nicol state by using a balanicol sensitive color plate 14 which is a combination of a balanicol sensitive color plate 14 and a balanicol sensitive color plate 14, the crossed nicol polarized light can be obtained by inserting and removing the balanicol sensitive color plate 14. It is possible to easily switch between observation and sensitive color observation according to the present invention. Note that the depolarization plate 13 may be a half wavelength plate. Further, the rose nicol sensitive color plate 14 may be switched with the analyzer 5.

FIG. 4 shows the optical system of a differential interference microscope which is a second embodiment of the polarized light observation apparatus according to the present invention, in which a rotatable polarizer 2 is placed between a white light source l and a condenser lens 7, and a condenser side Nomarski prisms 15 are arranged in order, and an objective lens-side Nomarski prism 1 is movable in a direction perpendicular to the optical axis between the objective lens 9 and the eyepiece lO.
6 and an analyzer 5 are arranged in this order.

Since this embodiment is configured as described above, normal differential interference observation can be performed by making the analyzer 5 and polarizer 2 cross nicol, and by making the polarizer 2 and the analyzer 5 para nicol. By moving the Nomarski prism 16 on the objective lens side to a position where the retardation on the optical axis becomes one-half wavelength, sensitive color observation according to the present invention can be performed. Also, conventionally 0
In order to enable both dark-field observation (differential interference observation) and sensitive color observation, the moving range of the Nomarski prism 15 on the objective lens side is a single wavelength plate 11 due to the difference in retardation. According to this embodiment, since the movement range is only one-half wavelength due to the retardation difference, the size of the Nomarski prism 16 on the objective lens side can be reduced, which is advantageous in terms of cost. be.

FIG. 5 shows the optical system of an epi-polarized polarizing microscope which is a third embodiment of the polarized light observation apparatus according to the present invention, in which a quarter-wave plate 17 is disposed between the objective lens 9 and the eyepiece lO.
, half mirror 18 and analyzer 5 are arranged in order, and light source 1
．． Illumination light from an illumination system consisting of a condenser lens 8 and a polarizer 2 is directed toward the sample 3 via a half mirror 18.

Since this embodiment is configured as described above, the illumination light passes through the quarter-wave plate 17 twice after passing through the polarizer 2 and before passing through the analyzer 5. The one-wave plate 17 plays substantially the same role as the half-wave plate 11 in the first embodiment.

Incidentally, when a Nomarski prism is used as the quarter-wave plate 17, an epi-illuminated differential interference microscope can be obtained which provides the same effects as in the second embodiment.

〔Effect of the invention〕

As described above, the polarized light observation apparatus according to the present invention has the practically important advantage of being able to perform sensitive color observation with twice the detection sensitivity of the conventional apparatus.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of the optical system of the polarization observation device according to the present invention,
FIG. 2 is a diagram showing the optical system of the first embodiment, FIG. 3 is a diagram showing the configuration of a paranicol sensitive color plate used in place of the half-wave plate in the first embodiment, and FIGS. The figures show the optical systems of the second and third embodiments, FIG. 6 shows the optical system of the conventional example, and FIG. 7 shows the spectral intensity of sensitive colors according to the observation device according to the present invention and the conventional example. It is a curve diagram. 1... White light source, 2... Polarizer, 3... Specimen, 5... Analyzer, 6... Eye, 7, 11...
・Half wavelength plate, 8... Condenser lens, 9
...Objective lens, 10...Eyepiece lens, 12.
... Auxiliary analyzer, 13... Depolarization plate, 14...
... Paranicol sensitive color plate, 15 ... Nomarski prism on the condenser side, 16 ... Nomarski prism on the objective lens side, 17 ... Quarter-wave plate, 18 ...
・Half mirror diagram Figure 1-3 Figure P4 Figure

Claims (1)

[Claims] A white light source, a polarizer for converting light from the white light source into linearly polarized light and irradiating it to a specimen, a phase element for causing retardation of a predetermined wavelength in the light from the specimen; In a polarization observation device comprising an analyzer for observing the polarization state of light that has passed through a phase element, the polarizer and the analyzer are substantially paranicol, and the phase element produces retardation of a half wavelength. A polarized light observation device characterized in that it allows