JP2001188122A - Optical element with dielectric multi-layered film and microscope using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element with a dielectric multi-layered film which can obtain a visual field while suppressing lightness unevenness and color unevenness as much as possible even when the element is arranged in an optical path and a microscope which uses it. SOLUTION: This microscope is equipped with a 1st optical system having a 1st lighting unit and an observation unit and a 2nd optical system having a 2nd lighting unit and an observation unit and the 1st lighting unit and observation unit are equipped with a polarizer 2 and an analyzer 5 respectively; and the 1st observation unit and 2nd observation unit have an objective 4 and an imaging lens 6 which are common and also have between the objective 4 and imaging lens 6 a dichroic mirror 5 equipped with a dielectric multi-layered film having such characteristics that the phase difference between a P-polarized and an S-polarized component generated when light in a wavelength range of 400 to 650 nm is transmitted is <=30 deg. and an optical member which holds the dielectric multi-layered film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element having a dielectric multilayer film and a microscope using the same, and more particularly to an optical element having a dielectric multilayer film such as a dichroic mirror used for an optical device such as a microscope and the like. It relates to the microscope used.

[0002]

2. Description of the Related Art A conventional optical microscope or the like may be constructed by using a dichroic mirror in which a dielectric multilayer film is deposited and held on a glass member in an optical path, particularly in an optical path of a polarized light beam. The case where the microscope is configured in such a manner will be described below.

[0003] When an automatic focus detection device (hereinafter referred to as AF) is combined with an epi-polarization microscope or an epi-differential interference microscope. In an epi-illumination microscope, an active AF is often used as a focusing mechanism in a field such as a metal microscope in view of the operation speed. FIG. 38 is a schematic configuration diagram showing a basic configuration example of an epi-polarization microscope. The epi-polarization microscope generally includes an illumination light source 1, a polarizer (polarizer) 2 as a first polarizing unit, a half mirror 3, an objective lens 4 as an observation optical system, and an analyzer as a second polarizing unit. (Analyzer) 5 and an imaging lens 6. An illumination optical system 7 such as a collector lens or a relay lens is disposed between the illumination light source 1 and the polarizer 2. In the epi-illumination, the objective lens 4 also functions as a part of the illumination optical system 7 and plays a role of a condenser lens.

Then, illumination light is emitted from the illumination light source 1 in a state of random polarization having various polarization directions, passes through the illumination optical system 7, and enters the polarizer 2. The polarizer 2 is an optical element having a characteristic of transmitting light in a specific polarization direction only. Illumination light incident on the polarizer 2 is:
When passing through, only light having a specific polarization direction is extracted and emitted (here, the polarizer 2 is assumed to pass only light having a polarization component whose polarization direction is perpendicular to the paper). The illumination light passing through the polarizer 2 is reflected by the half mirror 3 and illuminates the sample 8 via the objective lens 4.

The light reflected by the sample 8 passes through the objective lens 4 and the half mirror 3, and enters the analyzer 5. Like the polarizer 2, the analyzer 5 is an optical element having a characteristic of transmitting light only in a specific polarization direction. The analyzer 5 has a polarization component in a vibration direction orthogonal to the polarization direction of the polarizer (here, the same as the horizontal direction to the paper surface). (Polarized light component of the direction).

If the direction of polarization does not change when the illumination light is reflected by the specimen 8, the reflected light will enter the analyzer 5 as a polarized component in a direction perpendicular to the paper surface, and therefore can pass through the analyzer 5. Therefore, the image of the specimen 8 is not formed. On the other hand, if the polarization direction changes when the illumination light is reflected by the sample 8, reflected light having a polarization direction different from the direction perpendicular to the paper surface will be incident on the analyzer 5, and the incident light will include Is included, the polarized light component parallel to the paper surface passes through the analyzer 5, and the image 9 of the sample 8 is formed through the imaging lens.

FIG. 39 is a schematic configuration diagram showing an example of the basic configuration of an epi-illumination differential interference microscope. The epi-illumination differential interference microscope generally includes a Nomarski prism (or Wollaston prism) 10 between the half mirror 3 and the objective lens 4 in addition to the configuration of the epi-polarization microscope shown in FIG.

The illumination light of a random polarization state emitted from the illumination light source 1 passes through the illumination optical system 7 and only light having a specific polarization direction is extracted through the polarizer 2 and reflected by the half mirror 3. Thereafter, the light enters the Nomarski prism 10 and is separated into two linearly polarized light beams whose vibration planes are perpendicular to each other via the Nomarski prism 10 (here, it is assumed that the light is separated into two polarized light components at 45 ° to the paper surface). ), And enters the sample 8 via the objective lens 4. 2
The two linearly polarized light components are reflected by the sample 8 and then re-enter the Nomarski prism 10 via the objective lens 4 again.
They are combined into one through the Nomarski prism 10.
Thereafter, the combined two polarized light components are caused to interfere with each other via the analyzer 5, and form an interference image 9 of the sample 8 via the imaging lens 6.

FIG. 40 is a schematic configuration diagram showing a conventional example of an active AF used for an optical microscope. The laser beam emitted from the laser light source 11 is converted into a light beam parallel to the optical axis via a collimator lens 12, and then a half of the parallel light beam is cut off by a shielding plate 13 arranged in the optical path, and the other half of the parallel light beam is cut off. The light beam is polarized beam splitter 14
Is reflected by the light and passes through the λ / 4 plate 15
As a result, the light is focused on the image-side focal position P of the imaging lens 18.

Further, only the light of a specific wavelength range among the light beams is reflected by the dichroic prism 17 and passes through the imaging lens 18 and the objective lens 19 in order, and the measurement object on which the specimen 8 is placed is measured. The light is focused on the surface. The reflected light reflected by the sample 8 placed on the surface to be measured enters the dichroic prism 17 via the objective lens 19 and the imaging lens 18. Of the incident light, the light transmitted through the dichroic prism 17 is
It is observed through the eyepiece 20. The light in the specific wavelength range reflected by the dichroic prism 17 is
6. The light passes through the polarization beam splitter 14 via the λ / 4 plate 15 and is condensed on the two-division light receiving element 23 disposed at the condensing position of the condensing lens 16 via the shielding plate 21 and the condensing lens 22. It is supposed to be.

The two-divided light receiving element 23 is a photoelectric conversion element, converts reflected light from the surface to be measured into two corresponding electric signals, and sends out each electric signal to the signal processing system 24. The signal processing system 24 performs a predetermined operation to obtain a displacement signal of the measured surface.

In such an AF, since a laser in the infrared region is usually used, the dichroic prism 1
Reference numeral 7 has a characteristic of transmitting visible light for observation and reflecting infrared light.

In the AF, the optical path division between the laser light source 11 and the focus detection system (two-division light receiving element 23, signal processing system 24, etc.) is divided by the polarization beam splitter 14 and the λ / 4 plate 1
5 is performed. Therefore, when such an AF is combined with an epi-polarization microscope or an epi-differential interference microscope, an optical element such as an analyzer that affects the polarization from the AF cannot be arranged on the sample 8 side of the dichroic prism 17. .

In AF, a half mirror or the like cannot be used in place of a dichroic prism because of a large loss of light amount. Further, although it is possible to dispose the AF in the illumination system of the microscope, it becomes impossible to use the AF during dark-field observation without using the illumination system. Therefore, conventionally, when an AF as shown in FIG. 40 is combined with an epi-polarization microscope or an epi-differential interference microscope, the dichroic prism 17 is used as shown in FIGS.
In each case, the optical element from the condenser lens 16 to the signal processing system 24 in FIG. 40 is arranged as an AF optical system on the reflection side of the dichroic prism 17 while being arranged between the half mirror 3 and the analyzer 5. .

When epi-illumination fluorescence observation is performed with a transmission polarization microscope or a transmission differential interference microscope. FIG. 41 is a schematic configuration diagram showing a basic configuration example of a transmission polarization microscope. The transmission polarization microscope generally includes an illumination light source 1, a polarizer 2 as a first polarization unit, an illumination optical system 7, an objective lens 4 as an observation optical system, and an analyzer 5 as a second polarization unit.
And an imaging lens 6. Then, from the illumination light of a random polarization state emitted from the illumination light source 1, only a linear polarization component in a specific direction is extracted through the polarizer 2,
Light incident on the sample 8 via the illumination optical system 7, light transmitted through the sample 8 is incident on the analyzer 5 via the objective lens 4, and a polarized component of the light transmitted through the sample 8 whose polarization direction has been changed is analyzed by the analyzer 5. Passes through the imaging lens 6 to form an image of the specimen 8.

FIG. 42 is a schematic configuration diagram showing an example of the basic configuration of a transmission differential interference microscope. The transmission differential interference microscope generally has a Nomarski prism (or Wollaston prism) between the polarizer 2 and the illumination optical system 7 and between the objective lens 4 and the analyzer 5 in addition to the configuration of the transmission polarization microscope of FIG. 10, 10 'are arranged.
Then, as for the illumination light of a random polarization state emitted from the illumination light source 1, only light having a specific polarization direction is extracted through the polarizer 2, then enters the Nomarski prism 10, and passes through the Nomarski prism 10 to each other. The vibrating surface is separated into two perpendicular linearly polarized lights, and enters the sample 8 via the illumination optical system 7. After passing through the sample 8, the two linearly polarized light components enter the Nomarski prism 10 'through the objective lens 4, and are combined into one through the Nomarski prism 10'. Thereafter, the two combined polarization components are caused to interfere with each other via the analyzer 5, and are formed as an interference image of the sample 8 via the imaging lens 6.

In the field of medicine, biology, and the like, an epi-fluorescence microscope is used for observing the contours of cells and tissues in three dimensions and at the same time observing the positions of fluorescently labeled proteins and genes. FIGS. 43 and 44 are schematic configuration diagrams of microscopes in which the epi-illumination fluorescence observation microscope is combined with a transmission polarization microscope and a transmission differential interference microscope, respectively. Light emitted from an epi-illumination light source 26 such as a mercury lamp is guided to an excitation filter 27, and light passing through the excitation filter 27 is
The light is reflected by the dichroic mirror 28 and travels toward the specimen 8.
Fluorescence emitted from the specimen 8 is collected by the objective lens 4 in the same manner as the image from the illumination light source 1 and collected by the dichroic mirror 28.
The light passes through the absorption filter 29 and passes through the imaging lens 6 to form an image.

As described above, in the case of epi-illumination fluorescent light, the specimen is illuminated with excitation light and the fluorescence from the specimen is observed. I do. Further, in fluorescence observation, transmission differential interference observation is often performed in order to outline the transparent sample. Further, if a polarizing means such as an analyzer is arranged between the sample and the dichroic mirror, the illumination intensity of the fluorescent light is reduced. Therefore, the polarizing means is arranged on the optical path after passing through the dichroic mirror (the illumination light source 1). When viewed from the optical path from, the polarized light from the illumination light source 1 enters the dichroic mirror).

Known examples of such a microscope in which a dichroic mirror or the like is arranged in the optical path of polarized light include, for example, an epi-illumination differential interference microscope described in JP-A-9-179034 and JP-A-8-334700. Microscope using the active AF.

[0020]

However, when a dichroic mirror or the like is arranged in the optical path of the microscope, as in the microscopes described in JP-A-8-334700 and JP-A-9-179034, the observation field of view is reduced. There is a problem that brightness unevenness and color unevenness occur on the left and right sides.

Accordingly, the present invention has been made in view of the above-mentioned problems, and has an optical system having a dielectric multilayer film capable of obtaining a field of view with minimized brightness unevenness and color unevenness even when arranged in an optical path. It is an object to provide an element and a microscope using the element.

[0022]

The optical element having the dielectric multilayer film according to the present invention has a phase difference between the P-polarized light component and the S-polarized light component, which is generated when light in the wavelength range of 400 to 650 nm is transmitted, is 30. ° or less, and an optical member holding the dielectric multilayer film.

Further, a microscope using an optical element having a dielectric multilayer film according to the present invention has a first optical system having a first illumination unit and an observation unit, and a second optical system having a second illumination unit and an observation unit. The first illumination unit and the observation unit each include a polarizing member, and the first observation unit and the second observation unit have a common objective lens and an imaging lens,
A dielectric multilayer film having a characteristic in which a phase difference between a P-polarized component and an S-polarized component generated when light in a wavelength range of 400 to 650 nm is 30 ° or less, and an optical member holding the dielectric multilayer film. Wherein an optical element having the following structure is disposed between the objective lens and the imaging lens.

Further, a microscope using an optical element having a dielectric multilayer film according to the present invention includes a first optical system having an illumination unit and an observation unit, and a focus detection optical system.
The illumination unit and the observation unit each include a polarizing member, the first optical system has an objective lens common to the focus detection optical system, and P-polarized light generated when light in a wavelength range of 400 nm to 650 nm is transmitted. An optical element including a dielectric multilayer film having a characteristic in which the phase difference between the component and the S-polarized component is 30 ° or less, and an optical member holding the dielectric multilayer film. It is characterized by being arranged between the imaging lenses of the system.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The inventor of the present invention has proposed the optical characteristics of a dichroic mirror arranged in each of the above-mentioned microscopes,
In particular, simulations were performed with a focus on polarization characteristics, and the causes of brightness unevenness and color unevenness were analyzed. As a result, when linearly polarized light enters the dichroic mirror and passes through, a phase difference occurs between the P-polarized light component and the S-polarized light component of the linearly polarized light, which causes brightness unevenness and color unevenness. It was found that the larger the size, the larger the brightness unevenness and color unevenness.

For example, in observation with a polarizing microscope, a light beam (on-axis light beam) from an on-axis object point incident on the dichroic mirror is a polarization component of only one of the P-polarized component and the S-polarized component. When transmitted through the dichroic mirror, the light becomes linearly polarized light, but the light flux from the off-axis object point (off-axis light flux) contains both the P-polarized light component and the S-polarized light component. It has been found that a phase difference occurs with the S-polarized light, and when the amount of the phase difference is large, the linearly polarized light becomes elliptically polarized light, which causes unevenness in brightness in the visual field or coloring of the visual field. Further, in the observation with the differential interference microscope, since the light beam incident on the dichroic mirror includes both the S-polarized light and the P-polarized light through the polarization separation / synthesizing means such as the Nomarski prism, both of the on-axis light beam and the off-axis light beam, As described above, P-polarized light and S-polarized light
It has been found that a phase difference occurs between the polarized light and the polarized light, causing unevenness in brightness in the visual field and coloring of the visual field.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Embodiment 1 FIG. 1 is a view showing a first embodiment of a microscope using an optical element having a dielectric multilayer film according to the present invention, and is a schematic configuration diagram of a microscope in which an epifluorescence microscope is combined with a transmission polarization microscope. FIGS. 2A and 2B are state explanatory diagrams when the polarization state on the optical axis is viewed along the traveling direction of light. FIG. 2A shows the polarization state at a position a immediately after emission from an illumination light source, and FIG. Polarization state at position b immediately after passing,
(c) shows the polarization state at the position c immediately after passing through the analyzer.

The microscope according to the present embodiment has an illumination light source 1 as an optical system constituting a transmission polarization microscope as a first optical system.
And a polarizer (polarizer) 2 as first polarizing means
And an objective lens 4 as an observation optical system, an analyzer (analyzer) 5 as a second polarizing means, and an imaging lens 6. Further, between the illumination light source 1 and the polarizer 2, lenses 7, 7 'constituting an illumination optical system and a mirror 30 are provided.
Is arranged, and a condenser lens 7 ″ is arranged between the specimen 8 and the polarizer 2. And the illumination light source 1
The optical elements from to the condenser lens 7 ″ constitute a first illumination unit, and the optical elements from the objective lens 4 to the imaging lens 6 constitute a first observation unit.

As an optical system constituting an epi-fluorescence microscope which is a second optical system, an epi-light source 26 such as a mercury lamp is used.
, An excitation filter 27, a dichroic mirror 28, and an absorption filter 29. The dichroic mirror 28 is arranged between the objective lens 4 and the analyzer 5. Further, a lens 7 ′ ″ constituting an illumination optical system is disposed between the incident light source 26 and the excitation filter 27. Then, the dichroic mirror 2 is
The optical elements from the objective lens 4 to the objective lens 4 constitute a second illumination unit, and the optical elements from the objective lens 4 to the absorption filter 29 and the imaging lens 6 constitute a second observation unit.

Then, in the second optical system, the light emitted from the epi-illumination light source 26 is guided to the excitation filter 27 through the lens 7 ′ ″, and the light passing through the excitation filter 27 is reflected by the dichroic mirror 28. Then, the fluorescent light emitted from the sample 8 is collected by the objective lens 4 like the image from the illumination light source 1, passes through the dichroic mirror 28 and the absorption filter 29, and is imaged by the imaging lens 6. It has become.

In the first optical system, the illumination light from the illumination light source 1 has various polarization directions (including elliptically polarized light and circularly polarized light in addition to the illustrated linearly polarized light) as shown in FIG. The light is emitted in the state of random polarized light,
0, and enters the polarizer 2 via the lens 7 '. The illumination light incident on the polarizer 2 is, as shown in FIG.
When passing through, only light having a specific polarization direction that matches the vibration direction of the polarizer 2 is extracted and emitted (for example, here, only light of a polarization component whose polarization direction is perpendicular to the plane of FIG. 1 is passed. Shall be allowed). The illumination light having passed through the polarizer 2 illuminates the specimen 8 via the condenser lens 7 ″.

The light transmitted through the sample 8 enters the analyzer 5 via the objective lens 4 and the dichroic mirror 28. Like the polarizer 2, the analyzer 5 is an optical element having a characteristic of transmitting light in a specific polarization direction only. The analyzer 5 has a polarization component in a vibration direction orthogonal to the polarization direction of the polarizer (here, a component parallel to the plane of FIG. 1). (Polarized light component of the direction).

When there is no element that changes the vibration plane of the light in the sample, the polarization direction does not change when the illumination light passes through the sample 8, and the transmitted light is transmitted to the analyzer 5 as a polarization component in a direction perpendicular to the paper surface. Since the light is incident, the transmitted light cannot pass through the analyzer 5 and the image of the sample 8 is not formed. On the other hand, if the polarization direction changes due to scattering or the like when the illumination light passes through the sample 8, the transmitted light including a polarization component having a polarization direction different from the direction perpendicular to the paper surface enters the analyzer 5, and 2C, the polarized light component parallel to the paper surface passes through the analyzer 5, and the image 9 of the sample 8 is formed through the imaging lens 6, as shown in FIG. Imaged.

FIG. 3 is a partial side view of a polarized light microscope as shown in FIG. 1 viewed from the direction of the arrow A, showing the on-axis and off-axis polarized light beams from the sample in the polarizing microscope having such a configuration. In FIG. 3, the vibration direction of the analyzer is perpendicular to the paper surface, and the vibration direction of the polarizer is parallel to the paper surface. The vibration direction of the off-axis light beam L ₁ before being incident on the dichroic mirror 28 is orthogonal to the vibration direction of the analyzer 5 as in the vibration direction of the on-axis light beam L ₀ , as shown in FIG. since the Jikugaikotaba L ₁ is inclined relative to the axial light beam L _0, which is what was inclined with respect to the vibration direction of the orientation of the axial beam L _0.

With respect to this point, the state at the time of incidence on the dichroic mirror will be described in more detail with reference to FIGS.
FIG. 4 is a state explanatory view showing a polarization plane formed when on-axis light and off-axis light entering the dichroic mirror pass through the dichroic mirror in the microscope of FIG. In FIG. 4, for convenience of explanation, the illustrated varied from 3 positions of Jikugaikotaba L _1, shows the on-axis light and off-axis light as rays. Incidentally, M _X denotes the plane parallel to the polarization direction of the polarization direction and the off-axis light beam L ₁ of the axial rays L ₀ before entering the dichroic mirror. That is, the polarization direction of the polarization direction and the off-axis light beam L ₁ of the axial rays L ₀ before entering the dichroic mirror are both oriented perpendicular to the vibration direction of the analyzer.

FIGS. 5A and 5B are diagrams showing the polarization states of the on-axis light and the off-axis light after passing through the dichroic mirror, respectively, as viewed in the traveling direction of the light beam. FIG. Indicates the polarization state of off-axis rays. 5 (a), 5 (b)
In, the traveling direction of each light beam is perpendicular to the paper surface.

In FIG. 4, the light incident on the dichroic mirror includes a light ray and forms a P-polarized plane on a plane perpendicular to the dichroic mirror surface. That is, dichroic P polarization plane of the axial ray L ₀ incident on the dichroic mirror 28, the axial ray incident surface perpendicular M ₀ becomes to dichroic mirror surface M _d comprises an axial ray L _0, the dichroic mirror 28 L It coincides with a plane M ' ₀ perpendicular to the vibration direction of the linearly polarized light component of ₀ (that is, coincides with the vibration direction of the analyzer). In contrast, dichroic P polarization plane of dichroic mirror 28 axis ray L ₁ incident on, as shown by oblique lines, vertical plane M ₁ next to the dichroic mirror surface M _d include off-axis rays L _1, dichroic mirror The plane M ′ ₁ does not coincide with the plane M ′ ₁ perpendicular to the vibration direction of the linearly polarized light component of the off-axis light ray L ₁ incident on 28 (that is, coincides with the vibration direction of the analyzer).

[0038] Although P-polarized light and S polarized produces a phase difference transmitted through the dichroic mirror surface, the axial ray L ₀
When transmitted through the dichroic mirror surface, either one of the P-polarized light and the S-polarized light (in this embodiment, the S-polarized light component) is not separated and does not cause a phase difference. For this reason, as shown in FIG. 5A, the on-axis light beam L ₀ transmitted through the dichroic mirror becomes linearly polarized light having only the same S-polarized component as the polarization state when entering the dichroic mirror. Since the linearly polarized light having only the S-polarized light component does not pass through the analyzer whose vibration direction is orthogonal to the S-polarized light component, the center of the visual field is in a dark state.

On the other hand, when the off-axis ray L ₁ passes through the dichroic mirror surface, as shown in FIG.
Since the plane of polarization M ₁ and the plane M ′ ₁ perpendicular to the vibration direction of the linearly polarized light component of the off-axis light beam L ₁ do not coincide with each other and contain both P-polarized light and S-polarized light, the P-polarized light component And an S-polarized light component produce a phase difference. Off-axis rays with a phase difference are
It becomes elliptically polarized light as shown by the solid line in FIG. When elliptically polarized light enters the analyzer, the P-polarized light component passes through the analyzer and the field of view becomes bright. Also, if the phase difference between the P-polarized light component and the S-polarized light component generated by the dichroic mirror differs for each wavelength, the color will be colored.

Here, the optical axis and off-axis ray L ₁ in FIG.
Is defined as α, a unit vector perpendicular to the P polarization plane can be expressed by the following equation (1). (± tan α / ( ² tan ² α + 1) ^1/2 ), − (± 1 / ( ² tan ² α + 1) ^1/2 ), ± tan α / ( ² tan ² α + 1) ^1/2 ) (1) Further, the light passes through the polarizer. The unit Bertle of polarized light incident on the later dichroic mirror can be expressed by the following equation (2). ^{(Tanα / (1 + tan 2} α) 1/2, -1 / (1 + tan 2 α) 1/2, 0) ...... (2) Then, the angle between (1) and (2), in other words, the analyzer When the angle between the vibration direction and the P polarized light and theta _1, the following equation (3) is derived. ^{_{COSθ 1 = ± (tan 2 α}} + 1) / {(1 + 2tan 2 α) 1/2 × (1 + tan 2 α) 1/2} ...... (3)

Therefore, a simulation was performed on the brightness of the visual field in the microscope of the present embodiment by changing the phase difference between the P-polarized light and the S-polarized light generated by the dichroic mirror by a predetermined amount. The angle between the optical axis and the off-axis light ray L ₁ alpha is dependent on the imaging lens. In this simulation,
The imaging lens has a focal length of 180 mm and a field of view of 26.5.
mm. At this time, the angle α formed between the optical axis and the off-axis ray L ₁ is given by α = 13.5 / 180.
4.2 °. When this is substituted into the equation (3), the angle θ ₁ between the vibration direction of the analyzer and the P-polarized light is equal to 4.18868.
6 ≒ 4.2 °.

In the microscope having such a configuration, the phase difference between the P-polarized light and the S-polarized light generated when the light passes through the dichroic mirror is 0 °, 10 °, 20 °, 30 °, 45 °,
The simulation result about the amplitude of the light which passes through both ends of the visual field and the center of the visual field when it is set to 90 ° is shown. 6 to 11 simulate how much difference in brightness occurs between the center and both ends of the visual field when a phase difference occurs between P-polarized light and S-polarized light when linearly polarized light passes through a dichroic mirror. It is a graph which shows a result. 6 to 9 show an embodiment of the present invention, and FIGS. 10 and 11 show comparative examples of the present embodiment. 6 to 11.
The waveforms at the left and right ends of the middle and visual fields are denoted by G and F, respectively.
And the symbol E is attached to the waveform at the center of the visual field.

Of the items described above each graph,
"The angle between the oscillation direction of AN and the P-polarized light (4.2 °)" refers to the number of rotations of the polarization direction of the P-polarized light with respect to the oscillation direction of the analyzer when the off-axis principal ray enters the analyzer. The numerical value in parentheses indicates the angle. AN is an abbreviation for analyzer. Also, "Phase difference of PS polarized light generated by dichroic mirror (0 °)"
When linearly polarized light passes through the dichroic mirror,
It indicates the degree of phase difference between the orthogonal P-polarized light component and the S-polarized light component, and the numerical value in parentheses indicates the value of the generated phase difference. Each graph shows a time change of the amplitude of the light after passing through the analyzer. Since the temporal change of the amplitude of the light is very fast, the change cannot be observed by human eyes. Further, the human eye actually observes the intensity (brightness) which is a value obtained by squaring the amplitude value. However, there is a correlation between the change in amplitude and the change in brightness,
Here, a change in brightness can be estimated by comparing the maximum value of the amplitude.

In the case of a polarizing microscope, the phase shift of the PS polarized light at the dichroic mirror is β ° (the phase of the P polarized light is + β ° compared to the phase of the S polarized light), and the amplitude of the incident light is 1, P
Assuming that the angle between the polarized light and the vibration direction of the analyzer is θ ₁ , the light ray on the left side of the visual field (indicated by reference numeral L ₁ in FIG. 3).
In this simulation, the light beam at the left end of the visual field is used. Waveform G after transmission through the analyzer
, The following equation (4), cos (90- θ 1) cosθ 1 × cos (ωt + β) -cosθ 1 cos (90-θ 1) × cosωt ...... (4) sign L ₂ in field right beam (FIG. 3 It is shown in. Note that in this simulation for that.) by using the right edge of the light field of view, waveform F after the analyzer transmission, the following equation (5), -cos (90- θ 1) cosθ 1 × cos ( ωt + β) −cos θ ₁ cos (90−θ ₁ ) × cos ωt (5) Here, ω is an angular frequency, and t is time. The waveform G of the light ray L _{0 at the} center of the visual field after passing through the analyzer is zero.

FIG. 6 shows a waveform when the phase difference between the P-polarized light component and the S-polarized light component is 0 °. In FIG. 6, the amplitudes (vertical axis) of the waveforms G and F at both ends of the visual field and the waveform E at the center of the visual field are both zero. Therefore, the brightness (= amplitude ² ) also becomes 0, indicating that both the center and the periphery of the visual field are in a dark state.

FIGS. 7, 8, and 9 show waveforms when the phase difference between the P-polarized light component and the S-polarized light component is 10 °, 20 °, and 30 °, respectively. 7, 8, and 9, unlike FIGS. 6A and 6B, the waveforms G and F at both ends of the visual field are not flat but slightly have an amplitude. This indicates that the periphery of the visual field is slightly brighter than the center of the visual field.

Although this simulation is performed for one wavelength, the amplitude differs for different wavelengths. Therefore, in the actual observation visual field, a color difference (color unevenness) occurs in addition to a brightness difference (brightness unevenness) between the center of the visual field and both ends of the visual field.

FIGS. 10 and 11 show waveforms when the phase difference between the P-polarized light component and the S-polarized light component is 45 ° and 90 °, respectively. 10 and 11, the amplitudes of the waveforms G and F at both ends of the visual field are large and prominent. Therefore, a difference in brightness (unevenness in brightness) and a difference in color (unevenness in color) are extremely large between the center of the observation visual field and both ends of the visual field.

In the above simulation, the central portion of the field of view does not pass through the analyzer because the axial ray incident on the analyzer is only a polarization component orthogonal to the vibration direction of the analyzer. Therefore, the central part of the field of view is in a dark state irrespective of the characteristic of the phase difference between the P-polarized light component and the S-polarized light component on the dichroic mirror surface.

According to the simulation results of FIGS. 6 to 11, the larger the phase difference between the P-polarized light component and the S-polarized light component, the more the brightness differs between the ends of the visual field and the central part of the visual field. However, if the phase difference between the P-polarized light component and the S-polarized light component is 30 ° or less, the difference in brightness between the both ends of the visual field and the center of the visual field is relatively small, and is not so noticeable in actual observation. Therefore, the dielectric multilayer film constituting the dichroic mirror surface transmits light in the visible light wavelength range of about 400 nm to 650 nm, reflects light on the longer wavelength side, and also transmits light in the wavelength range of about 400 nm to 650 nm. An optical element such as a dichroic mirror having such an optical characteristic that the phase difference between the P-polarized light component and the S-polarized light component generated when light is transmitted is 30 ° or less. When used in a microscope, brightness unevenness and color unevenness in the visual field can be suppressed.

Embodiment 2 FIG. 12 is a view showing a second embodiment of a microscope using an optical element having a dielectric multilayer film according to the present invention, and is a schematic configuration of a microscope in which a transmission differential interference microscope and an incident fluorescence microscope are combined. FIG. FIG. 13 is a state explanatory diagram when the polarization state on the optical axis is viewed along the traveling direction of light, (a) is a polarization state at a position a immediately after emission from the illumination light source,
(b) is the polarization state at position b immediately after passing through the polarizer, (c) and (d) are polarization states at position c immediately after passing through the first Nomarski prism, and (e) is the polarization state at the second Nomarski prism. (F) shows the polarization state at the position d immediately after passing through the analyzer, and (f) shows the polarization state at the position e immediately after passing through the analyzer.

The differential interference microscope used in this embodiment is shown in FIG.
In addition to the configuration of the polarizing microscope described above, between the polarizer 2 and the condenser lens 7 ″, and between the objective lens 4 and the analyzer 5
The first Nomarski prism 10 and the second Nomarski prism 10 'are arranged between the first and second Nomarski prisms 10'. Other configurations are almost the same as those of the polarization microscope of FIG. still,
A Wollaston prism can be used instead of the Nomarski prism.

Then, in the first optical system, the illumination light is emitted from the illumination light source 1 in a state of random polarization having various polarization directions as shown in FIG. , The illumination optical system 7 ′, and the polarizer 2
Incident on. Illumination light incident on the polarizer 2 is shown in FIG.
As shown in (b), only light having a specific polarization direction that matches the vibration direction of the polarizer 2 when passing therethrough is extracted and emitted (for example, here, the polarization direction is perpendicular to the plane of FIG. 12). Only light having a strong polarization component is allowed to pass).

The illumination light having passed through the polarizer 2 is separated into two linearly polarized lights (see FIGS. 13 (c) and 13 (d)) whose vibration planes are orthogonal to each other via a Nomarky prism 10. The two separated linearly polarized lights enter the sample 8 via the condenser lens 7. These two linearly polarized lights are
At the sample position, the light beams are parallel to each other at a slight interval.

After passing through the sample 8, the two linearly polarized lights enter the Nomarski prism 10 'through the objective lens 4 and are parallel to each other via the Nomarski prism 10', as shown in FIG. The two beams are combined into one while maintaining their mutually linearly polarized light in an orthogonal state.

The polarized light combined into one through the Nomarski prism 10 'enters the analyzer 5 via the objective lens 4 and the dichroic mirror 28. Like the polarizer 2, the analyzer 5 is an optical element having a characteristic of transmitting light only in a specific polarization direction. Here, the analyzer 5 is arranged to transmit only light of a polarization component in a direction parallel to the plane of FIG. Have been. The polarized light incident on the analyzer 5 interferes via the analyzer 5, and when passing through, only light having a specific polarization direction coinciding with the vibration direction of the analyzer 5 is extracted as shown in FIG. Then, an interference image 9 of the sample 8 is formed through the imaging lens 6.

FIG. 14 is a partial side view of the on-axis and off-axis polarized light beams from the specimen in the differential interference microscope having such a configuration, as viewed from the direction of arrow A of the microscope of FIG. In FIG. 14, the vibration direction of the analyzer 5 is perpendicular to the paper surface. As shown in FIG. 14, the off-axis light beam L ₁₁ and the off-axis light beam L ₁₂ are tilted with respect to the direction of vibration of the on-axis light beam L ₀ because they are tilted with respect to the on-axis light beam L ₀ . It has become something.

In the differential interference microscope of this embodiment, the linearly polarized light incident on the dichroic mirror includes a P-polarized light component and an S-polarized light component. Since a phase difference occurs, linearly polarized light becomes elliptically polarized light even for off-axis rays and on-axis rays. This will be described in more detail with reference to FIG.

FIG. 15 shows the polarization states of the on-axis light and the off-axis light incident on the dichroic mirror and the elliptically polarized light generated when the light passes through the dichroic mirror, as viewed in the light traveling direction (direction of arrow B) in FIG. FIG.

As described above, the light beam emitted from the second Nomarski prism 10 ', which is a polarization combining element, has two linearly polarized light beams that are orthogonal to each other, both in the on-axis light beam and the off-axis light beam. The two linearly polarized lights are shown in FIG.
As shown in FIG. 3E, they overlap on the same optical path. Therefore, the left and right off-axis rays and the on-axis rays entering the dichroic mirror 28 have two polarization directions orthogonal to each other.
Two linearly polarized lights are included.

FIGS. 15C and 15D show axial rays involved in image formation at the center of the visual field, and FIG. 15C shows one state of linearly polarized light whose polarization directions are orthogonal to each other. (d) shows the other one of the linearly polarized lights whose polarization directions are orthogonal to each other. FIG.
5 (c) and (d), the P-polarized light and S
The polarization corresponds to the vibration direction of the analyzer and the vibration direction of the polarizer, respectively. When a phase difference occurs between the P-polarized light and the S-polarized light when the incident polarized light passes through the dichroic mirror, the polarized light becomes elliptically polarized light or linearly polarized light having a different direction from the incident polarized light, as shown in the figure.

FIGS. 15 (a) and 15 (b) show off-axis rays related to image formation on the left side of the field of view. FIG. 15 (a) shows one of linearly polarized lights whose polarization directions are orthogonal to each other, and FIG. Shows the other one of the orthogonal linearly polarized lights. Both linearly polarized lights enter the dichroic mirror at the same incident angle, but have different polarization directions. Therefore, the state of occurrence of the phase difference between the P-polarized component and the S-polarized component is different, and as a result, the state of the generated elliptically polarized light is also different.

FIGS. 15 (e) and 15 (f) show off-axis rays related to image formation on the right side of the visual field, where (e) is one of linearly polarized lights whose polarization directions are orthogonal, and (f) is the polarization direction. Shows the other one of the orthogonal linearly polarized lights. As in FIGS. 15A and 15B, the state of the generated elliptically polarized light is different.

In the microscope having such a configuration, the phase difference between the P-polarized light and the S-polarized light generated when the light passes through the dichroic mirror is 0 °, 10 °, 20 °, 30 °, 45 °,
The simulation result about the amplitude of the light which passes through both ends of the visual field and the center of the visual field when it is set to 90 ° is shown. FIGS. 16 to 34 are graphs showing simulation results of brightness at the right end and the left end of the visual field when a phase difference occurs between P-polarized light and S-polarized light by the dichroic mirror. 17 to 28 show an embodiment of the present invention, and FIGS. 29 to 34 show comparative examples of the present embodiment.

The items described in the graphs are almost the same as those in the simulation of the polarizing microscope shown in FIGS. Also, as is well known, in the differential interference microscope, by adjusting the retardation amount of the polarization combining element,
The brightness (contrast) of the entire observation visual field can be adjusted. For example, “Phase (180 °) added for contrast adjustment” in FIG. 16 indicates this, and the numerical value in parentheses is the amount of retardation and is described in terms of an angle. The graph in FIG. 16 shows the brightest state, and the amplitude values of the waveforms in the graphs shown in FIGS. 17 to 34 are normalized with reference to the maximum amplitude value of the waveform in the brightest state in FIG. When the retardation amount is 0 °, the center of the visual field is in a dark state.

In the case of a differential interference microscope, the phase shift of the PS polarized light at the dichroic mirror is β ° (the phase of the P polarized light is + β ° compared to the phase of the S polarized light), the amplitude of the incident light is 1, and the P polarized light is 1. Assuming that the angle between the plane and the polarization plane of the analyzer is θ, and the phase added for contrast adjustment is + Γ °, the left side of the visual field (the left end in this simulation)
The waveform G of the light beam after passing through the analyzer is as follows: ｛cos (45−θ) cosθ × cos (ωt + β) −cos (45 + θ) cos (90−θ) × cosωt−cos (45 + θ) cosθ × cos (ωt + β + Γ) −cos (45−θ) cos (90−θ) × cos (ωt + Γ)｝ (6) The waveform F of the light ray on the right side of the field of view (the right end in this simulation) after passing through the analyzer is expressed as ｛cos ( 45 + θ) cosθ × cos (ωt + β) + cos (45 + θ) cos (90−θ) × cosωt−cos (45−θ) cosθ × cos (ωt + β + Γ) + cos (45 + θ) cos (90−θ) × cos (ωt + Γ)｝ ... (7) The waveform E of the light ray at the center of the visual field after transmission through the analyzer is given by: ｛{cos (ωt + β) −cos (ωt + β + Γ)} Succoth can. Here, ω is an angular frequency, and t is time.

FIGS. 17 to 19 show waveforms when no phase difference occurs between the P-polarized light component and the S-polarized light component when transmitted through the dichroic mirror. FIG. 17 shows a waveform when the phase to be added (the amount of retardation) is 0 ° and the phase difference between the P-polarized component and the S-polarized component is 0 °. In FIG. 17, the waveforms G and F at both ends of the visual field and the waveform E at the center of the visual field are both
The amplitude (vertical axis) is 0. Accordingly, the brightness (= amplitude ² ) is also 0, which indicates that the center and the periphery of the visual field are both in the same dark state.

FIGS. 18 and 19 show that the phase difference between the P-polarized light component and the S-polarized light component remains 0 °, the retardation amount is 20 °,
This is a waveform when the angle is set to 40 °. In this case, the field of view becomes brighter according to the amount of retardation, which can also be seen from the occurrence of amplitude in the waveform indicating the state of light. However, since the phase difference between the P-polarized light component and the S-polarized light component remains at 0 °, the amplitude has the same value at the center and the periphery of the visual field. Therefore, in this state, there is no difference in brightness between the center of the visual field and the peripheral portion.

FIGS. 20 to 22 and FIGS. 23 to 25 show the state of light at the center of the visual field and at the periphery of the visual field when the phase difference between the P-polarized light component and the S-polarized light component is 10 ° and 20 °, respectively. Is shown. 20 and 23, FIG. 21, and FIG.
4, FIGS. 22 and 25 show that the retardation amount is 0
The waveforms in the case of °, 20 °, and 40 ° are shown. FIG. 20, FIG.
3 has a retardation amount of 0 °, and therefore, originally, FIG.
Similarly, the periphery of the field of view should be in a dark state as in the center of the field of view. However, as shown in FIGS. 20 and 23, the waveform is not flat but has a slight amplitude. This indicates that the periphery of the visual field is slightly brighter than the center of the visual field.
However, since the amplitude of the waveform indicating the right end of the visual field and the amplitude of the waveform indicating the left end of the visual field are the same, there is no difference between the brightness of the right end of the visual field and the brightness of the left end of the visual field.

FIGS. 21 and 24 show that the retardation amount is 20.
It is a waveform in the case of °. 20 and 23, there is a difference between the amplitude of the waveform indicating the right end of the visual field and the amplitude of the waveform indicating the left end of the visual field. Therefore, the brightness at both ends of the visual field differs from the center of the visual field, and the brightness at the right end of the visual field differs from the brightness at the left end of the visual field. Note that this simulation is for one wavelength, and different wavelengths have different amplitudes. Therefore, in an actual observation visual field, a color difference (color unevenness) occurs in addition to a brightness difference (brightness color unevenness).

FIGS. 22 and 25 show that the retardation amount is 40.
It is a waveform in the case of °. It can be seen that the difference in brightness between the right end of the visual field and the left end of the visual field is further increased as compared with the waveform when the retardation amount is 20 °.

FIGS. 26 to 28, 29 to 31, and 32
34 to 34 show the state of light at the center of the field of view and the periphery of the field of view when the phase difference between the P-polarized component and the S-polarized component is 30 °, 45 °, and 90 °, respectively.

As can be seen from the above simulation results, the greater the phase difference between the P-polarized light component and the S-polarized light component, the more the brightness differs between the right end of the visual field and the left end of the visual field. However, if the phase difference between the P-polarized component and the S-polarized component is 30 ° or less, the brightness between the right end of the visual field and the left end of the visual field is not so noticeable. Therefore, the dielectric multi-layer film constituting the dichroic mirror surface has a thickness of 400 nm to 6 nm.
It transmits light in the visible light wavelength range of about 50 nm, reflects light on the longer wavelength side, and has a wavelength of 400 nm.
An optical element such as a dichroic mirror configured to have optical characteristics such that a phase difference between a P-polarized component and an S-polarized component generated when light in a wavelength region of about 650 nm is transmitted is 30 ° or less. Is preferably used for such a differential interference microscope. Also, P
It can be said that it is more preferable to have optical characteristics such that the phase difference between the polarized light component and the S-polarized light component is 20 ° or less.

Embodiment 3 FIG. 35 is a view showing a third embodiment of a microscope using a dielectric multilayer film according to the present invention, and is a schematic configuration diagram of a microscope in which an epi-polarization microscope is combined with an AF unit. In the microscope of this embodiment, a dichroic mirror 28 is arranged between the analyzer 5 and the half mirror 30 in addition to the configuration shown in FIG. On the optical path reflected by the dichroic mirror 28, for example, an AF optical system 31 composed of a member shown on the left side of the dichroic prism 17 in FIG. The focus detection optical system is constituted by the above optical elements. The basic configuration of the optical system of the epi-polarization microscope, which is the first optical system of the microscope of this embodiment, is the same as the configuration of FIG. When an AF optical system is combined with a polarizing microscope, a new light source for detecting a focus state is required. This light source is arranged inside the AF optical system 31 (not shown). 2 to 5 also correspond to the microscope of the present embodiment, similarly to the microscope of the first embodiment.

Then, in the first optical system, the illumination light from the illumination light source 1 is used as in the case of the microscope shown in FIG.
As shown in (a), the light is emitted in the state of random polarization having various polarization directions, and enters the polarizer 2 via the illumination optical system 7. Illumination light incident on the polarizer 2 is shown in FIG.
As shown in (b), only light having a specific polarization direction that matches the vibration direction of the polarizer 2 when passing therethrough is extracted and emitted (for example, in this case, the polarization direction is perpendicular to the plane of FIG. 35). Only light having a strong polarization component is allowed to pass). The illumination light passing through the polarizer 2 is reflected by the half mirror 30 and illuminates the sample 8 via the objective lens 4.

The light reflected by the sample 8 enters the analyzer 5 via the dichroic mirror 28. Like the polarizer 2, the analyzer 5 is an optical element having a characteristic of transmitting light only in a specific polarization direction. Here, the analyzer 5 is arranged so as to transmit only light of a polarization component in a direction parallel to the plane of FIG. Have been.

At this time, when there is no element that changes the vibration plane of the light in the sample, the polarization direction does not change when the illumination light is reflected by the sample 8, and the reflected light is converted into a polarization component in a direction perpendicular to the paper surface. Since the light enters the analyzer 5, the reflected light cannot pass through the analyzer 5, and the image of the specimen 8 is not formed. On the other hand, if the polarization direction changes when the illumination light is reflected by the sample 8, transmitted light including a polarization component having a polarization direction different from the direction perpendicular to the paper surface will be incident on the analyzer 5, and will be parallel to the paper surface. 2C, the polarized light component parallel to the paper surface passes through the analyzer 5, and the image 9 of the sample 8 is formed through the imaging lens 6, as shown in FIG. .

In the microscope of this embodiment, as in the microscope of the embodiment of FIG. 1, linearly polarized light having only one polarization direction is incident on the dichroic mirror. However, the polarization direction of the off-axis light beam reaching the right end of the visual field and the polarization direction of the off-axis light beam reaching the left end of the visual field are different with respect to the incident surface of the dichroic mirror.
The amount of phase difference between the polarized light component and the S-polarized light component is different between an off-axis ray reaching both ends of the field of view and an off-axis ray reaching the center of the field of view. As a result, a difference in brightness and color occurs between both ends of the visual field and the center of the visual field.
As in the embodiment, light in the visible light wavelength range of about 400 nm to 650 nm is transmitted, light on the longer wavelength side is reflected, and P generated when light in the wavelength range of about 400 nm to 650 nm is transmitted. Since it has a dielectric multilayer film having optical characteristics such that the phase difference between the polarization component and the S-polarization component is 30 ° or less, the first
Similar to the microscope of the embodiment, the simulation results of FIGS. 6 to 11 are obtained, and the problems of the brightness shift and the color shift as described above do not occur.

Embodiment 4 FIG. 36 is a view showing a fourth embodiment of a microscope using a dielectric multilayer film according to the present invention, and is a schematic configuration diagram of a microscope in which an AF unit is combined with an incident-light differential interference microscope. The microscope of the present embodiment has a Nomarski prism 10 between the half mirror 30 and the objective lens 4 in addition to the configuration of the microscope of FIG. In the configuration of the epi-illumination interference microscope as in this embodiment, the illumination light passes through one Nomarski prism twice, so that the two Nomarski prisms 10 and 10 'in the microscope of FIG.
Two Nomarski prisms are also used. Other configurations are almost the same as those of the polarization microscope of FIG. Note that the microscope of this embodiment is also similar to the microscope of the second embodiment.
13 to 15 correspond to this case.

Then, in the first optical system, the illumination light is emitted from the illumination light source 1 in a state of random polarization having various polarization directions as shown in FIG. , And is incident on the polarizer 2. Polarizer 2
As shown in FIG. 13B, only the light having a specific polarization direction that matches the vibration direction of the polarizer 2 when passing through is extracted and emitted as shown in FIG. It is assumed that only light having a polarization component whose polarization direction is perpendicular to the plane of FIG.

The illumination light having passed through the polarizer 2 is reflected by the half mirror 30 and passes through the Nomarski prism 10 into two linearly polarized light beams whose vibration planes are orthogonal to each other (FIG. 13).
(c) and (d)). The two separated linearly polarized lights enter the sample 8 via the objective lens 4. This 2
The two linearly polarized light beams are parallel to each other at a small interval at the sample position.

After the two linearly polarized lights are reflected by the sample 8, they enter the Nomarski prism 10 again through the objective lens 4 and are mutually parallel through the Nomarski prism 10 as shown in FIG. Are combined into one while maintaining the linearly polarized light.

The polarized light combined into one through the Nomarski prism 10 enters the analyzer 5 through the half mirror 30 and the dichroic mirror 28. The analyzer 5, like the polarizer 2, is an optical element having a characteristic of transmitting light only in a specific polarization direction. Here, the analyzer 5 is arranged so as to transmit only light of a polarization component in a direction parallel to the plane of FIG. Have been. The polarized light incident on the analyzer 5 interferes through the analyzer 5 and, when passing through,
As shown in FIG. 13 (f), only light having a specific polarization direction corresponding to the vibration direction of the analyzer 5 is extracted, and an interference image 9 of the sample 8 is formed via the imaging lens 6.

In the microscope of this embodiment, the simulation results of FIGS. 16 to 34 are obtained as in the differential interference microscope of the second embodiment.

In the present invention, the smaller the angle of incidence on the dichroic mirror, the smaller the phase difference between P-polarized light and S-polarized light is. Therefore, as shown in FIG. 37, instead of the arrangement configuration in which the light enters the dichroic mirror directly at an incident angle of 45 ° as indicated by the broken line, a mirror and a half mirror are arranged, and the incident angle with respect to the dichroic mirror is reduced. A configuration in which the size is reduced (two-mirror) is also conceivable, but is not preferable because the thickness of the unit is increased and the peripheral light quantity is likely to be insufficient, as indicated by an arrow in the figure. Therefore, it is preferable that the polarization characteristics be reduced when the angle of incidence on the dichroic mirror with respect to the normal to the plane of incidence is 45 °. For example,
40 ° to normal to the dichroic mirror's entrance surface
It is preferable to configure the dichroic mirror and the microscope so as to satisfy the conditions of the above embodiments when the light is incident at an angle of 50 °.

Note that the microscope using the optical element having the dielectric multilayer film of the present invention is not limited to the microscopes of the above embodiments, and the configuration in which the optical elements are arranged so that polarized light passes through the dichroic mirror. It is applicable to microscopes. For example, a microscope in which the optical system of an epi-illumination polarization microscope is used as a first optical system and the optical system of an epi-fluorescence microscope is used as a second optical system, or an epi-illumination differential interference microscope is used as a first optical system. A microscope combining an optical system as a second optical system, a transmission polarization microscope as a first optical system, and a microscope combining this with a focus detection optical system, and a transmission differential interference microscope as a first optical system. If an optical element having a dielectric multilayer film such as a dichroic mirror of the present invention is applied to a microscope or the like in which a focus detection optical system is combined, the same effects as those of the above embodiments can be obtained.

As described above, the optical element having the dielectric multilayer film according to the present invention and the microscope using the same have the following features in addition to the features described in the claims. .

(1) The optical element according to claim 1, wherein the phase difference is 20 ° or less.

(2) The phase difference is generated when the light is incident at an incident angle of 40 ° to 50 ° with respect to a normal to the incident surface of the optical element. 1 or an optical element having the dielectric multilayer film according to (1).

(3) The dielectric multilayer film has a thickness of 400 nm.
The light transmission device according to any one of claims 1, 2 and 3, wherein the light transmission device transmits light in a wavelength range of 650 nm to 650 nm and reflects light on a longer wavelength side than the wavelength range. An optical element having the dielectric multilayer film according to the above.

(4) The microscope according to claim 2, wherein the phase difference is 20 ° or less.

(5) The phase difference is generated when the light is incident at an incident angle of 40 ° to 50 ° with respect to a normal to the incident surface of the optical element. 2 or the microscope according to (4).

(6) The dielectric multilayer film has a thickness of 400 nm.
The light transmission device according to any one of claims 2, 4 and 5, wherein the light transmission device has a characteristic of transmitting light in a wavelength range of ６650 nm and reflecting light on a longer wavelength side than the wavelength range. Microscope as described.

(7) The first optical system is an epi-polarization optical system, and the second optical system is an epi-fluorescence optical system, according to any one of the above (4) to (6). Microscope.

(8) The first optical system is a transmission polarization optical system, and the second optical system is an epi-fluorescence optical system, according to any one of the above (4) to (6). Microscope.

(9) The first optical system is an epi-illumination differential interference optical system, and the second optical system is an epi-fluorescence optical system. Microscope as described.

(10) The first optical system is a transmission differential interference optical system, and the second optical system is an epi-illumination fluorescent optical system. Microscope as described.

(11) The microscope according to claim 3, wherein the phase difference is 20 ° or less.

(12) The phase difference occurs when the light is incident at an incident angle of 40 ° to 50 ° with respect to a normal to the incident surface of the optical element. 3 or the microscope according to (11).

(13) When the dielectric multilayer film has a thickness of 400n
4. A light transmission device having a characteristic of transmitting light in a wavelength range of m to 650 nm and reflecting light on a longer wavelength side than the wavelength range. The microscope according to 1.

(14) The microscope according to any one of the above (11) to (13), wherein the first optical system is an epi-polarization optical system.

(15) The microscope according to any one of (3) to (13), wherein the first optical system is a transmission polarization optical system.

(16) The microscope according to any one of the above (11) to (13), wherein the first optical system is an incident-light differential interference optical system.

(17) The microscope according to any one of (11) to (13), wherein the first optical system is a transmission differential interference optical system.

[0105]

As described above, according to the present invention, it is possible to obtain a field of view in which brightness unevenness and color unevenness are suppressed as much as possible, even if they are arranged in the optical path.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of a microscope using an optical element having a dielectric multilayer film according to the present invention, and is a schematic configuration diagram of a microscope in which an epifluorescence microscope is combined with a transmission polarization microscope.

FIGS. 2A and 2B are explanatory diagrams of the polarization state on the optical axis when viewed along the traveling direction of light. FIG. 2A is a polarization state at a position a immediately after emission from an illumination light source, and FIG. ) Is the polarization state at position b immediately after passing through the polarizer,
(c) is a schematic configuration diagram showing a polarization state at a position c immediately after passing through an analyzer and showing a first embodiment of a stereomicroscope according to the present invention.

FIG. 3 is a partial side view showing on-axis and off-axis polarized light beams from a sample in a polarizing microscope.

FIG. 4 is a state explanatory view showing a polarization plane formed when on-axis light and off-axis light entering the dichroic mirror pass through the dichroic mirror in the microscope of FIG.

FIGS. 5A and 5B are diagrams showing polarization states of on-axis light and off-axis light after passing through a dichroic mirror along the traveling direction of light rays, respectively. FIG. 5A is a polarization state of on-axis light rays, and FIG. The polarization state of off-axis rays is shown.

FIG. 6 is a diagram illustrating an example of the brightness of the center and both ends of a visual field when linearly polarized light passes through a dichroic mirror and a phase difference of 0 ° occurs between P-polarized light and S-polarized light. 9 is a graph showing a result of a simulation of whether a difference occurs.

FIG. 7 shows an example of the brightness of the center and both ends of the visual field when linearly polarized light passes through a dichroic mirror and a phase difference of 10 ° occurs between P-polarized light and S-polarized light. 9 is a graph showing a result of a simulation of whether a difference occurs.

FIG. 8 is a diagram illustrating an example of the brightness of the center and both ends of the visual field when linearly polarized light passes through a dichroic mirror and a phase difference of 20 ° occurs between P-polarized light and S-polarized light. 9 is a graph showing a result of a simulation of whether a difference occurs.

FIG. 9 is a diagram showing an example of the brightness of the center and both ends of the visual field when linearly polarized light passes through a dichroic mirror and a phase difference of 30 ° occurs between P-polarized light and S-polarized light. 9 is a graph showing a result of a simulation of whether a difference occurs.

FIG. 10 shows a comparative example of the present invention in which, when linearly polarized light passes through a dichroic mirror and a phase difference of 45 ° occurs between P-polarized light and S-polarized light, the brightness of the center and both ends of the visual field 9 is a graph showing a result of a simulation of whether a difference occurs.

FIG. 11 is a comparative example of the present invention, when linearly polarized light passes through a dichroic mirror and a phase difference of 90 ° occurs between P-polarized light and S-polarized light; 9 is a graph showing a result of a simulation of whether a difference occurs.

FIG. 12 is a view showing a second embodiment of a microscope using an optical element having a dielectric multilayer film according to the present invention, and is a schematic configuration diagram of a microscope combining a transmission differential interference microscope and an epifluorescence microscope.

FIGS. 13A and 13B are explanatory diagrams of the polarization state on the optical axis when viewed along the traveling direction of light. FIG. 13A is a polarization state at a position a immediately after emission from an illumination light source, and FIG. )
Is the polarization state at position b immediately after passing through the polarizer, (c) and (d) are polarization states at position c immediately after passing through the first Nomarski prism, and (e) is immediately after passing through the second Nomarski prism. (F) shows the polarization state at the position d immediately after passing through the analyzer.

FIG. 14 is a partial side view showing on-axis and off-axis polarized light beams from a specimen in a differential interference microscope.

15 is a traveling direction of light in FIG. 14 (direction of arrow B);
FIG. 5 is a diagram showing polarization states of on-axis light and off-axis light incident on a dichroic mirror and elliptically polarized light generated when the light passes through the dichroic mirror, as viewed along the line.

FIG. 16 shows a simulation performed on the brightness at the right end and the left end of the visual field when the phase difference between the P-polarized light and the S-polarized light generated by the dichroic mirror is 0 ° and the phase added for contrast adjustment is 180 °. It is a graph which shows a result.

FIG. 17 shows the brightness at the right and left ends of the visual field when the phase difference between the P-polarized light and the S-polarized light generated in the dichroic mirror according to the embodiment of the present invention is 0 ° and the phase added for contrast adjustment is 0 °. 6 is a graph showing a result of performing a simulation on the height.

FIG. 18 shows the brightness at the right and left ends of the visual field when the phase difference between the P-polarized light and the S-polarized light generated in the dichroic mirror according to the embodiment of the present invention is 0 ° and the phase added for contrast adjustment is 20 °. 6 is a graph showing a result of performing a simulation on the height.

FIG. 19 shows the brightness at the right and left ends of the visual field when the phase difference between the P-polarized light and the S-polarized light generated in the dichroic mirror according to the embodiment of the present invention is 0 ° and the phase added for contrast adjustment is 40 °. 6 is a graph showing a result of performing a simulation on the height.

FIG. 20 shows the right and left ends of the visual field when the phase difference between the P-polarized light and the S-polarized light generated in another dichroic mirror according to the embodiment of the present invention is 10 ° and the phase added for contrast adjustment is 0 °. 9 is a graph showing another result of performing a simulation on the brightness at.

FIG. 21 illustrates a case where the phase difference between P-polarized light and S-polarized light generated by another dichroic mirror according to the embodiment of the present invention is 10 ° and the phase added for contrast adjustment is 20 °.
11 is a graph showing another result of performing a simulation on the brightness at the right end and the left end of the visual field.

FIG. 22 shows a case where the phase difference between P-polarized light and S-polarized light generated by another dichroic mirror according to the embodiment of the present invention is 10 ° and the phase added for contrast adjustment is 40 °.
11 is a graph showing another result of performing a simulation on the brightness at the right end and the left end of the visual field.

FIG. 23 shows the right end of the field of view when the phase difference between P-polarized light and S-polarized light generated by still another dichroic mirror in the embodiment of the present invention is 20 ° and the phase added for contrast adjustment is 0 °. It is a graph which shows the result of having performed simulation about the brightness at the left end.

FIG. 24 shows the relationship between the right end of the field of view when the phase difference between P-polarized light and S-polarized light generated by still another dichroic mirror in the embodiment of the present invention is 20 ° and the phase added for contrast adjustment is 20 °. It is a graph which shows the result of having performed simulation about the brightness at the left end.

FIG. 25 shows the relationship between the right end of the field of view when the phase difference between the P-polarized light and the S-polarized light generated by another dichroic mirror according to the embodiment of the present invention is 20 ° and the phase added for contrast adjustment is 40 °. It is a graph which shows the result of having performed simulation about the brightness at the left end.

FIG. 26 shows the right end of the visual field when the phase difference between the P-polarized light and the S-polarized light generated in still another dichroic mirror of the embodiment of the present invention is 30 ° and the phase added for contrast adjustment is 0 °. It is a graph which shows the result of having performed simulation about the brightness at the left end.

FIG. 27 shows the right end of the visual field when the phase difference between the P-polarized light and the S-polarized light generated in still another dichroic mirror of the embodiment of the present invention is 30 ° and the phase added for contrast adjustment is 20 °. It is a graph which shows the result of having performed simulation about the brightness at the left end.

FIG. 28 shows the relationship between the right end of the field of view when the phase difference between P-polarized light and S-polarized light generated by still another dichroic mirror of the embodiment of the present invention is 30 ° and the phase added for contrast adjustment is 40 °. It is a graph which shows the result of having performed simulation about the brightness at the left end.

FIG. 29 shows the brightness at the right end and the left end of the visual field when the phase difference between the P-polarized light and the S-polarized light generated by the dichroic mirror of the comparative example of the present invention is 45 ° and the phase added for contrast adjustment is 0 °. 6 is a graph showing a result of performing a simulation on the height.

FIG. 30 shows the brightness at the right end and the left end of the visual field when the phase difference between P-polarized light and S-polarized light generated in the dichroic mirror of the comparative example of the present invention is 45 ° and the phase added for contrast adjustment is 20 °. 6 is a graph showing a result of performing a simulation on the height.

FIG. 31 shows the brightness at the right end and the left end of the visual field when the phase difference between P-polarized light and S-polarized light generated in the dichroic mirror of the comparative example of the present invention is 45 ° and the phase added for contrast adjustment is 40 °. 6 is a graph showing a result of performing a simulation on the height.

FIG. 32 shows the right and left ends of the visual field when the phase difference between the P-polarized light and the S-polarized light generated by another dichroic mirror of the comparative example of the present invention is 90 ° and the phase added for contrast adjustment is 0 °. 6 is a graph showing the result of a simulation performed on the brightness at the point.

FIG. 33 shows a case where the phase difference between P-polarized light and S-polarized light generated in another dichroic mirror of the comparative example of the present invention is 90 ° and the phase added for contrast adjustment is 20 °.
It is a graph which shows the result of having performed simulation about brightness at the right end and the left end of a visual field.

FIG. 34 shows a case where the phase difference between P-polarized light and S-polarized light generated in another dichroic mirror of the comparative example of the present invention is 90 ° and the phase added for contrast adjustment is 40 °.
It is a graph which shows the result of having performed simulation about brightness at the right end and the left end of a visual field.

FIG. 35 is a view showing a third embodiment of a microscope using a dielectric multilayer film according to the present invention, and is a schematic configuration diagram of a microscope combining an epi-polarization microscope and an AF unit.

FIG. 36 is a view showing a fourth embodiment of the microscope using the dielectric multilayer film according to the present invention, and is shown by an AF differential interference microscope;
It is a schematic structure figure of a microscope which combined a unit.

FIG. 37 is an explanatory diagram showing a configuration of a two-mirror as one means for reducing an incident angle on a dichroic mirror in the microscope of the present invention.

FIG. 38 is a schematic configuration diagram showing a basic configuration example of an epi-polarization microscope.

FIG. 39 is a schematic configuration diagram showing a basic configuration example of an epi-illumination differential interference microscope.

FIG. 40 is a schematic configuration diagram showing a conventional example of an active AF used for an optical microscope.

FIG. 41 is a schematic configuration diagram showing a basic configuration example of a transmission polarization microscope.

FIG. 42 is a schematic configuration diagram showing a basic configuration example of a transmission differential interference microscope.

FIG. 43 is a schematic configuration diagram of a microscope in which an epi-illumination fluorescence observation microscope is combined with a transmission polarization microscope.

FIG. 44 is a schematic configuration diagram of a microscope in which an epi-illumination fluorescence observation microscope is combined with a transmission differential interference microscope.

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Polarizer 3 Half mirror 4 Objective lens 5 Analyzer 6 Imaging lens 7, 7 ', 7' "Illumination optical system 7" Condenser lens 8 Sample 9 Primary image 10, 10 'Nomarski prism 11 Laser light source 12 Collimator Lens 13 Shielding plate 14 Polarizing beam splitter 15 λ / 4 plate 16 Condensing lens 17 Dichroic prism 18 Imaging lens 19 Objective lens 20 Eyepiece 21 Shielding plate 22 Condensing lens 23 Two-piece light receiving element 24 Signal processing system 26 Light source 27 Excitation filter 28 Dichroic mirror 29 Absorption filter 30 Mirror 31 AF (automatic focus detection) optical system

Claims (3)

[Claims] 1. A dielectric multilayer film having a characteristic in which a phase difference between a P-polarized light component and an S-polarized light component generated when light in a wavelength range of 400 to 650 nm is 30 ° or less, and holding the dielectric multilayer film An optical element comprising: an optical member. A first optical system having a first illumination unit and an observation unit; and a second optical system having a second illumination unit and an observation unit, wherein the first illumination unit and the observation unit are respectively provided. A polarizing member, the first observation unit and the second observation unit have a common objective lens and an imaging lens, and a P-polarized light component and a S-polarized light component generated when light in a wavelength range of 400 to 650 nm is transmitted. A phase difference between the polarization component and the optical element having a dielectric multilayer film having a characteristic of 30 ° or less and an optical member holding the dielectric multilayer film, between the objective lens and the imaging lens. A microscope characterized by being arranged. A first optical system having an illumination unit and an observation unit; and a focus detection optical system, wherein the illumination unit and the observation unit each include a polarizing member, and the first optical system includes the focus detection optical system. A dielectric multilayer film having a common objective lens with the system, wherein a phase difference between a P-polarized component and an S-polarized component generated when light in a wavelength range of 400 nm to 650 nm is transmitted is 30 ° or less; A microscope, wherein an optical element including an optical member holding a dielectric multilayer film is disposed between the objective lens and the imaging lens of the first optical system.