WO2008010316A1

WO2008010316A1 - Polarizer and microscope with polarizer

Info

Publication number: WO2008010316A1
Application number: PCT/JP2007/000767
Authority: WO
Inventors: Shojiro Kawakami; Yoshihiko Inoue
Original assignee: Photonic Lattice, Inc.
Priority date: 2006-07-17
Filing date: 2007-07-17
Publication date: 2008-01-24
Also published as: JP5021645B2; JPWO2008010316A1

Abstract

[PROBLEMS] To provide not a polarizer having a liner polarization axis but a novel polarizer not influenced by polarization state conversion attributed to a lens and so forth (removal) when used in a polarization microscope and a polarization microscope in which a novel polarizer is used and light is ideally blocked when a sample having no polarization conversion action is observed. [MEANS FOR SOLVING PROBLEMS] The above problem is unavoidable when a lens is constituted of a curved surface rotationally symmetric with respect to the optical axis and the polarizing axis is linear. Therefore, the problem can be fundamentally solved by using a polarizer having a transmission axis rotationally symmetric with respect to the optical axis similarly to the lens. That is, the problem can be solved by using a polarizer having a concentric transmission axis or a redial transmission axis in a polarization microscope.

Description

Specification

Polarizer, and microscope using polarizer

Technical field

[0001] The present invention relates to a polarizer, and a microscope using the polarizer. More specifically, the present invention uses a polarizer designed to have a concentric transmission axis, a polarizer designed to have a transmission axis radially, and a combination of such polarizers. This is related to a microscope that can effectively extract and observe only the components.

Background art

[0002] Polarizers are elements that have the effect of transmitting only the polarization component of the incident light along the transmission axis, and are widely used for measuring the polarization state, microscopes using polarized light, sunglasses, etc. (For example, see Japanese Patent No. 3 4 8 6 3 5 5). Ordinary polarizers have a unidirectional transmission axis indicated by a straight line and a unidirectional blocking axis.

[0003] Polarizing microscopes are used for the purpose of observing an observation target composed of a transparent substance, for example, a living cell under a microscope. This uses the change in the refractive index of the object to be observed and birefringence, and is used to observe living cells without staining. This polarizing microscope generally uses a polarizer for irradiating the observation object with polarized light and a polarizer (analyzer) for adjusting the brightness of the observation image according to the direction of the polarized light. For example, when the polarization axes of the irradiation-side polarizer and the observation-side polarizer are orthogonal, only the part of the observation target that has a polarization conversion effect is brightly observed. Based on this principle, a polarizing microscope may be able to observe the internal structure of transparent bodies that cannot be seen normally. For polarizing microscopes with these characteristics, polarizers with a transmission axis that is linearly unidirectional have been used.

[0004] For example, Japanese Patent No. 2 8 2 4 5 1 (Patent Document 1) states that “a cold mirror film that reflects infrared rays of incident light rays and transmits visible light is formed on a glass substrate. The other side of the glass substrate is coated with a polarizing beam splitter film that splits the incident unpolarized light beam into two linearly polarized light beams whose polarization planes intersect each other. A polarizer characterized by this is disclosed (claim 8), and a polarizing microscope using the polarizer is disclosed. Again, the polarizing microscope disclosed in the above document is intended to use one or more polarizers having a linear polarization axis.

[0005] However, when a polarizer having a linear polarization axis is used for the irradiation-side polarizer and the observation-side polarizer, the objective lens has a curved surface. As a result, there was a problem that even if there was no observation sample, it could not be completely darkened. In particular, a polarization microscope using a high-magnification objective lens has a problem that the above-described polarization conversion occurs remarkably. In other words, it was difficult to achieve a high extinction ratio with a polarization microscope using a polarizer having a linear polarization axis as in the past.

[0006] The polarization rotation phenomenon associated with the lens transmission described above is based on the fact that the transmittance on an inclined surface that is not perpendicular to the light traveling direction is a P wave whose incident surface and electric field vibration direction are parallel, and an s wave perpendicular to this. One of the causes is different. In addition, a shift in the phase of the P wave and s wave caused by a multilayer film such as an antireflection film provided on the lens surface also causes the polarization state to change. In this way, by generating different transmittance and phase difference between the P wave and s wave on the lens surface, the light containing both wave components changes from linearly polarized light to elliptically polarized light, and the principal axis direction rotates. Resulting in. For this reason, for example, when the irradiation-side polarizer and the observation-side polarizer are used with their transmission axes orthogonal to each other, even a portion where the observation sample does not exist cannot be made a complete dark portion. There is a problem that the detection of the weak polarization conversion effect is obstructed.

[0007] Furthermore, in the polarization observation using linearly polarized light as the irradiation light, the optical characteristics of the observation sample having an optical anisotropy axis in the direction parallel and perpendicular to the irradiated polarization axis could not be observed. For this reason, when performing polarization observation, the sample is evaluated by comparing multiple observation results in which the polarization direction of the irradiated light is set in at least two directions. A lot of things happened, which contributed to the increase in the observation process. Patent Document 1: Japanese Patent No. 2 8 2 8 4 5 1

Disclosure of the invention

Problems to be solved by the invention

[0008] The present invention uses a polarizer having a rotationally symmetric polarization axis instead of a linear polarization axis so that the polarization plane deviation caused by a lens or the like can be reduced when used in a polarization microscope. The purpose is to provide a new polarizer that is not easily affected.

[0009] An object of the present invention is to provide a polarizing microscope that uses a novel polarizer and blocks light at a high extinction ratio when there is no sample.

[0010] An object of the present invention is to provide a polarizing microscope capable of obtaining an observation image having no direction dependency by a single observation.

[001 1] An object of the present invention is to provide a polarization microscope capable of effectively observing minute defects, scratches, fiber structures, and the like.

Means for solving the problem

[0012] The first aspect of the present invention basically provides a polarizer having a transmission axis concentrically or radially that is not a polarizer having parallel polarization planes. These polarizers are basically polarized light that has a concentric transmission axis or a radial transmission axis (thus, the blocking axis is concentric) for the irradiation-side and observation-side polarizers. Useful for microscopes. In other words, in a polarization microscope, local disturbance of the polarization state (polarization conversion) occurs due to the lens of the objective lens. Of course, in a microscope other than the polarization microscope, local disturbance of the polarization state does not cause any problem, and even in the polarization microscope, the light due to the polarization state conversion by the lens is negligible. However, when observing a sample with a slight polarization conversion effect, such as when using a polarizing microscope to observe a biological sample, the polarization conversion effect of the slight lens itself affects the detection limit of weak signal light. . In the present invention, basically, an irradiation-side polarizer and an observation-side polarizer each having a concentric transmission axis or a radial transmission axis (thus, a blocking axis is concentric) are used. The The microscope is basically an axisymmetric optical system, except for possible causes such as assembly errors and the photoelastic effect due to the residual stress of the lens. In such a system, light with concentric polarization is not converted to light with radial polarization when passing through a lens or space, and vice versa, so with the polarizer of the present invention, A polarizing microscope that is not affected by a lens or the like can be obtained.

That is, the first aspect of the present invention relates to a polarizer in which transmission axes are provided concentrically. In a preferred embodiment of the first aspect of the present invention, the transmission axis is the polarizer described above, wherein a plurality of the transmission axes are provided concentrically from one center. For example, such a polarizer may be manufactured by a self-cloning method using a substrate that has a plurality of concavities and convexities on the surface. That is, for example, the layers constituting the polarizer have a plurality of concentric periodic structures, and such layers need only be formed in multiple layers. In addition, a polarizer having transmission axes concentrically arranged may be a polarizer having a layer in which a radial periodic structure is formed in multiple stages from the center to the outer edge. A preferred embodiment of the first aspect of the present invention relates to the polarizer described in any one of the above, which is composed of a self-cloning photonic crystal. A specific example of a polarizer with concentric transmission axes is a concentric periodic structure composed of self-cloning photonic crystals composed of multiple layers, each layer having a period of 2 3 2 nm. The thickness of the S i 0 ₂ layer is 5 8 nm, the thickness of the Ta ₂ O ₅ layer is 81 nm, and the Si 0 ₂ layer and the Ta ₂ 0 ₅ layer are alternately 4 One example is a polarizer that consists of zero layers and transmits polarized light having an electric field component parallel to the tangent of the circumference of each concentric circle for input light with a wavelength between 5220 nm and 540 nm. Another specific example of a polarizer having transmission axes concentrically arranged is a self-cloning photonic crystal composed of multiple layers, has a radial periodic structure, and a substrate pitch of 2 At 45 nm, S i 0 ₂ is 1 45 nm, Ta ₂ 0 ₅ is 1 25 nm, and there are 27 layers of polarizers.

[0014] Another aspect of the first aspect of the present invention, which is different from the above, relates to a polarizer in which a transmission axis is provided radially from one point (thus, a blocking axis is concentric). Of this aspect In a preferred embodiment, the present invention relates to the polarizer described above, which has a layer in which a radial periodic structure is formed in multiple stages from the center to the outer edge, and further comprises a self-cloning photonic crystal. More specifically, the layers constituting the polarizer have a periodic structure, and the radial structure is formed in multiple stages from the center to the outer edge in order to keep the interval between the radially formed periodic structures within a certain range. The thing in which the period structure is formed is mention | raise | lifted. More specifically, a polarizer with a transmission axis radiating from one point is used as a self-chromoscope composed of multiple layers.

—Consisting of a ning photonic crystal, each layer has a radial periodic structure of 2 3 2 nm, the Si 0 ₂ layer thickness is 5 8 nm, and the Ta ₂ 0 ₅ layer thickness is 8 1 nm, 40 and 40 layers of S i 0 ₂ layers and Ta ₂ 0 ₅ layers are stacked alternately. For input light with a wavelength of 5 20 nm or more and 5 40 nm or less, One example is a polarizer that transmits polarized light having an electric field component perpendicular to the tangent line of the circumference. A polarizer with a transmission axis radiating from one point is composed of a self-cloning photonic crystal composed of multiple layers, has a concentric periodic structure from the center, and a substrate pitch of 2 45 nm. Thus, S i 0 ₂ is 1 4 5 nm, and D 3 ₂ 0 ₅ is 1 2 5 。.

[0015] A second aspect of the present invention includes: a light source; and a first polarizer that transmits light from the light source, the transmission axis of which is provided concentrically around the optical axis; and the first polarization An observation sample stage on which a sample irradiated with light transmitted through a child is mounted; light transmitted through a sample mounted on the observation sample stage or light reflected from a sample mounted on the observation sample stage is transmitted; The present invention relates to a polarizing microscope comprising: an objective lens; and a second polarizer in which light transmitted through the objective lens is transmitted and a transmission axis is provided radially about the optical axis. The “second polarizer in which the transmission axis is provided radially from the optical axis” is preferably the polarizer described above in which the transmission axis is provided radially from the center of the polarizer. That is, as the first polarizer and the second polarizer, the above-described polarizers can be used as appropriate.

[001 6] In other words, a conventional polarizing microscope uses a polarizer having a linear polarization axis, and therefore it is affected by the lens and cannot obtain a high extinction ratio. won. In the polarizing microscope of the present invention, a polarizer having a transmission axis concentrically arranged and a polarizer having a transmission axis radially arranged around the optical axis are used in combination. The extinction ratio can be obtained.

[0017] Another aspect of the second aspect of the present invention, different from the above, is a light source; and a first polarizer that transmits light from the light source, and whose transmission axis is provided radially about the optical axis; An observation sample stage on which a sample irradiated with light transmitted through the first polarizer is mounted; light transmitted through the sample mounted on the observation sample stage or reflected from a sample mounted on the observation sample stage A polarizing microscope comprising: an objective lens that transmits light; and a second polarizer that transmits light that has passed through the objective lens and that has a transmission axis concentrically centered on the optical axis.

[0018] Another aspect of the second aspect of the present invention is different from the above in that a light source; the light from the light source is transmitted; a transmission axis is radial about the optical axis or concentric about the optical axis A first polarizer provided on the observation sample; an observation sample stage on which a sample irradiated with light transmitted through the first polarizer is mounted; a light transmitted through the sample mounted on the observation sample stage; or Light reflected from the sample mounted on the observation sample stage is transmitted; an object lens; light transmitted through the objective lens is transmitted; an optical rotator that makes the polarization main axis direction orthogonal; and light transmitted through the optical rotator is And a second polarizer having a transmission axis similar to that of the first polarizer, and a polarizing microscope.

That is, by providing the optical rotator, the polarization plane is shifted by 90 degrees, so that the function of the polarizing microscope described above can be achieved by one type (preferably one) polarizer. In other words, “a second polarizer having a transmission axis similar to that of the first polarizer” means, for example, that the first polarizer is a polarizer in which the transmission axis is provided concentrically around the optical axis. In this case, the polarizers may be the same polarizers, or the transmission axes may be provided concentrically around the optical axis, and the first polarizer may be provided radially around the optical axis. In the case of a polarizer, it may be the same polarizer or a polarizer whose transmission axis is provided radially around the optical axis. [0020] Another embodiment of the second aspect of the present invention is different from the above in that a light source; light from the light source is transmitted; a transmission axis is radial about the optical axis or concentric about the optical axis. A first polarizer provided in the optical axis; a light rotator that transmits light transmitted through the first polarizer; a polarization rotator that orthogonally crosses the principal axis direction of polarization; and a sample irradiated with light transmitted through the optical rotator An observation sample stage; light transmitted through the sample mounted on the observation sample stage or light reflected from the sample mounted on the observation sample stage is transmitted; an object lens; and light transmitted through the optical rotator And a second polarizer having a transmission axis similar to that of the first polarizer, and a polarizing microscope comprising:

[0021] A preferred embodiment of the polarization microscope according to the second aspect of the present invention includes a condensing lens that condenses light from the light source between the light source and the first polarizer; The first polarizer is disposed between the light source and the observation sample and is disposed at the pupil position of the condenser lens; the second polarizer is disposed at the pupil position of the objective lens; The present invention relates to any one of the polarizing microscopes.

[0022] In the polarization microscope of the present invention according to this aspect, by arranging a polarizer having a rotationally symmetric polarization axis at the pupil position of the condenser lens and the objective lens, or at a position conjugate to them, the omnidirectional straight line is obtained. Because the light with the same polarization mixed is incident on the sample, an observation image with no direction dependency can be obtained with a single observation. In addition, in this polarizing microscope, when the sample surface is a uniform transparent body, the light that has passed through a certain point of the concentric polarizer placed at the front stage of the observation sample is reflected by the radial polarizer placed at the rear stage of the observation sample. It is blocked by gathering at one corresponding point. On the other hand, if the observed sample has non-uniform components, more components are transmitted depending on the heterogeneity. Therefore, the smaller the inhomogeneity point in the observation sample is, the more the transmittance tends to increase, and an observation image that emphasizes high-frequency components as a whole can be obtained. Therefore, the polarization microscope according to this mode is suitable for observing minute defects, scratches, and fibrous structures.

[0023] The microscope according to the third aspect of the present invention includes a concentric polarizer with a transmission axis and a radial polarizer with a transmission axis at the pupil position of the condenser lens and the pupil position of the objective lens. A finer structure can obtain higher resolution images. It relates to the microscope. In other words, this microscope has a polarizer with a concentric transmission axis at the pupil position of the condenser lens, for example, and a polarizer with a radial transmission axis at the pupil position of the objective lens. Alternatively, for example, this microscope has a polarizer with a radial transmission axis at the position of the condensing lens and a polarizer with a concentric transmission axis at the pupil position of the objective lens. As demonstrated by the examples to be described later, by providing either a concentric polarizer with a transmission axis or a radial polarizer with a transmission axis at the vertical position of the condenser lens and the vertical position of the objective lens, The higher the resolution, the higher the resolution. In addition, as a microscope of this aspect, a configuration of a normal microscope can be appropriately adopted as a configuration other than the above polarizer.

The invention's effect

[0024] According to the present invention, there is provided a novel polarizer having a transmission axis that is concentric or a transmission axis that is radial (and thus the blocking axis is concentric) that is not obtained by a polarizer having parallel polarization planes. They can be used effectively in the polarizing microscopes mentioned above.

[0025] According to the present invention, the irradiation-side polarizer and the observation-side polarizer each have a concentric transmission axis or a radial transmission axis (thus, the blocking axis is concentric). Therefore, it is possible to provide a polarizing microscope that is not affected by the distortion of the polarization plane caused by a lens such as an objective lens, and that blocks light when there is no sample.

[0026] According to the present invention, it is possible to provide a polarization microscope capable of acquiring an observation image having no direction dependency by one observation.

[0027] According to the present invention, it is possible to provide a polarizing microscope capable of effectively observing minute defects, scratches, fibrous structures, and the like.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail with reference to the drawings. Figure 1 shows the direction of the transmission axis in a polarizer with transmission axes concentrically arranged. As shown in FIG. 1, the first aspect of the present invention relates to a polarizer in which transmission axes are provided concentrically. Such a polarizer, for example, has multiple concavities and convexities on the surface. What is necessary is just to manufacture by the self-cloning method using such a board | substrate. That is, for example, the layers constituting the polarizer have a plurality of concentric periodic structures, and such layers need only be formed in multiple layers. Figure 2 shows the direction of the transmission axis in a polarizer with a transmission axis radiating from one point. As shown in Fig. 2, in a polarizer with a transmission axis that radiates from one point, the transmission axis is radiated at a uniform rate from one point (preferably the center of gravity of the polarizer). Since the transmission axis and the blocking axis are orthogonal, the blocking axis of such a polarizer is concentric.

[0029] Fig. 3 shows a schematic diagram of a polarizer having a transmission axis in a concentric or radiant shape using a self-cloning photonic crystal. Figure 3 (a) shows an example of a polarizer with transmission axes concentrically arranged. Figure 3 (b) shows an example of a polarizer with a transmission axis radiating from one point. Figure 3 (c) shows an example of a polarizer having layers in which radial periodic structures are formed in multiple stages. Figure 4 shows an example of a self-cloning photonic crystal. As shown in Fig. 4, a self-cloning photonic crystal is generally formed by stacking a number of layers with a specific periodic structure in a direction parallel to and perpendicular to the grooves on the surface. Different transmission characteristics can be designed for each polarized light with electric field oscillation. For example, as shown in Fig. 4, polarized light having electric field vibration parallel to the groove can be reflected, and polarized light having electric field vibration perpendicular to the groove can be transmitted. Also, by adjusting the pitch of the unevenness and the film thickness of the multilayer film, it is possible to transmit only polarized light having electric field vibration parallel to the grooves, contrary to Fig. 4. Therefore, according to the self-cloning method, a polarizer having the shape shown in Fig. 3 (a) and Fig. 3 (b) can be manufactured.

[0030] The one shown in Fig. 3 (c) is designed to have three steps so that the radial periodic structure is divided into three equal parts from the center to the outer edge. It is not limited to the one, but it may be 2 steps or 4 steps or more. A preferred embodiment of such a polarizer is that the layers constituting the polarizer have a periodic structure, so that the interval between the radially formed periodic structures is within a certain range. Thus, a radial periodic structure is formed in multiple stages. The size of the polarizer is not particularly limited, but is preferably a size that can be used as a lens for a polarizing microscope.

[0031] The polarizer as described above is, for example, disclosed in JP-A-10-335758, JP-A-2000-258645, JP-A-2001-74954, JP-A-2 001-249235, JP-A-2004. _45779 can be appropriately created using a manufacturing technique disclosed in the publication. A desirable method for producing self-cloning photonic crystals is described below. Quartz is used as the substrate material, and periodic irregularities with a pitch of about half the operating wavelength are formed using a photolithography process. A photonic crystal can be obtained by forming a film using a sputtering apparatus. Materials for forming, for example _{_{S io 2, N b 2 O}} s, or the like T a ₂ 0 _5, it is possible to apply Yibin selected from materials that can be sputtered. For example S i 0 ₂ and N b ₂ O _{if s} self cloning deposited a multilayer film using a 4 in the film forming apparatus: while flowing the A r and oxygen gas in the first partial pressure of about 0. 5 P Apply voltage with a gas pressure of a and perform sputtering. By applying the substrate bias at the same time, film formation and etching can be performed at the same time, and self-cloning film formation can be realized. Note that the power applied to the substrate bias should be 10% or less of the deposition power.

[0032] As demonstrated by the examples described later, for example, using a quartz substrate, the substrate pitch (one period of irregularities) is 232 nm, the S i O ₂ layer thickness is 58 nm, Ta ₂ O _When 40 layers each with a thickness of 81 nm are stacked, only polarized light having an electric field component parallel to the unevenness is transmitted at a wavelength of 520 to 540 n (with an extinction ratio of 40 dB or more). did it. In other words, in this case, when the substrate groove is concentric, a transmission axis having a concentric shape can be obtained. Conversely, if the substrate groove is radial, the transmission axis can be made radial. For example, even if the polarizer has a layer in which a radial periodic structure is formed in multiple stages from the center to the outer edge, a transmission axis having a radial transmission axis can be obtained. Thus, the basis Based on this embodiment, the groove provided on the plate and the polarizer with parallel transmission axes should be adjusted appropriately according to the groove shape of the substrate, the substrate pitch, the material constituting each layer, and the film thickness of each layer. Can be manufactured. The substrate pitch is not particularly limited, but is appropriately adjusted within about half the wavelength of incident light, for example, in the range of 50 nm to 60 nm, preferably in the range of 100 nm to 500 nm. do it. The thickness of each layer composing a polarizer composed of self-cloning crystals may be adjusted as appropriate from 20 nm to 150 nm. In addition, it is preferable that each layer has two different types of layers as one pair, and multiple pairs are stacked. The number of such pairs (number of layers) is, for example, from 10 to 20 layers, and may be from 20 to 100 layers.

On the other hand, as demonstrated in the examples described later, even if the same material is used, the substrate pitch is 2 45 nm, S i 0 ₂ is 1 45 nm, and Ta ₂ 0 ₅ is 1 2 5 nm. In the case of 27 layers, a polarizer that transmits only polarized light having an electric field component perpendicular to the irregularities at a wavelength of 520 to 5500 nm is obtained. In this case, if the substrate groove is concentric, a polarizer with a radial transmission axis can be obtained, and if the substrate groove is radial, a transmission axis can be obtained with a concentric circle. For example, even a polarizer having a layer in which a radial periodic structure is formed in multiple stages from the center to the outer edge can be obtained with concentric transmission axes. As described above, the polarizer with the transmission axis orthogonal to the groove provided on the substrate is adjusted according to this example by adjusting the groove shape of the substrate, the substrate pitch, the material constituting each layer, the film thickness of each layer, etc. Can be manufactured. The substrate pitch is not particularly limited, but is appropriately adjusted within about half the wavelength of the incident light, for example, in the range of 50 nm to 60 nm, preferably in the range of 100 nm to 500 nm. That's fine. The thickness of each layer composing a polarizer composed of self-cloning crystals may be adjusted as appropriate from 20 nm to 150 nm. In addition, it is preferable that each layer has two different layers as one pair, and multiple pairs are stacked. The number of such pairs (number of layers) is, for example, 10 or more and 20 or less layers, and may be 20 or more and 100 or less layers. In addition to the self-cloning photonic crystal, a polarizer having a radial transmission axis can be realized by a wire grid polarizer having a shape as shown in FIG. 5, for example. Figure 5 is a schematic diagram of a wire-grid polarizer. However, self-cloning photonic crystals are preferred because they can be manufactured with high accuracy and can exhibit the polarization adjustment function.

Next, a polarizing microscope according to the second aspect of the present invention will be described. According to a second aspect of the present invention, there is provided a light source; a first polarizer that transmits light from the light source, a transmission axis that is provided concentrically with the optical axis as a center; and transmission through the first polarizer. An observation sample stage on which the sample irradiated with the irradiated light is mounted; an objective lens through which the light transmitted through the sample mounted on the observation sample stage or the light reflected from the sample mounted on the observation sample stage is transmitted; And a second polarizer that transmits light passing through the objective lens and whose transmission axis is provided radially around the optical axis. The optical axis is the axis through which light passes in a polarizing microscope. In the polarization microscope of the present invention, a polarizer having a transmission axis concentrically arranged and a polarizer having a transmission axis radially arranged around the optical axis are used in combination. A high extinction ratio can be obtained.

[0036] Another aspect of the second aspect of the present invention is the light source; a first polarizer that transmits light from the light source, the transmission axis is provided radially about the optical axis; An observation sample stage on which a sample irradiated with light transmitted through the first polarizer is mounted; light transmitted through the sample mounted on the observation sample stage or reflected from a sample mounted on the observation sample stage A polarizing microscope comprising: an objective lens that transmits light; and a second polarizer that transmits light that has passed through the objective lens and that has a transmission axis concentrically centered on the optical axis. When the light from the light source passes through the first polarizer, the plane of polarization is adjusted. The light transmitted through the first polarizer is irradiated onto the sample on the observation sample stage. Light transmitted through the observation sample or reflected from the observation sample passes through the objective lens. The light that has passed through the objective lens passes through the second polarizer. The light that has passed through the second polarizer will be observed through an objective lens. FIG. 6 shows an example of the configuration of a polarizing microscope. In the microscope (1 1) in Fig. 6, the light collected by the condenser lens (1 3) and output horizontally in the lamp house (1 2) is bent upward by the mirror (1 4) at the bottom of the microscope. Passes in the order of irradiation side polarizer (15), condenser lens (16), observation sample (17), objective lens (18), observation side polarizer (analyzer) (19). An image is obtained through the eyepiece [20]. This microscope has a transmissive configuration. One of the irradiation side polarizer (15) and the observation side polarizer (analyzer) (19) is a polarizer having a concentric transmission axis as shown in Fig. 1, and the rest are shown in Fig. 2. Such a polarizer has a radial transmission axis. As shown in Fig. 3 (a), Fig. 3 (b), and Fig. 3 (c), a polarizer with a concentric or radiative transmission axis is realized with a self-cloning photonic crystal polarizer. ). The light that has a predetermined transmission pattern in the irradiation-side polarizer (15) reaches the observation-side polarizer without adjusting the polarization plane, and the observation-side polarizer (analyzer) (1 9) means that everything will be shut off. However, only the component whose polarization plane is shifted by the observed sample (17) is observed. Of course, a microscope with a configuration other than that shown in Fig. 6, such as a reflection type, may be used. A high-sensitivity polarization microscope that is not affected by polarization conversion by the lens is configured by providing a concentric or radial polarizer with transmission axes at the position of the irradiation side polarizer and observation side polarizer in Fig. 6. can do.

FIG. 7 is a diagram showing an example of a polarization microscope in which an optical rotator composed of a crystal rotator or a liquid crystal is inserted between the irradiation side polarizer and the observation side polarizer. As shown in Fig. 7, by inserting an optical rotator composed of a crystal rotator or a liquid crystal between the irradiation side polarizer and the observation side polarizer, the extinction state between the two polarizers can be reduced to some extent. The amount of light transmitted through the viewing-side polarizer can be relaxed and contribute to preliminary positioning for observation.

FIG. 8 is a diagram showing an example of a polarization microscope in which a rotator (Faraday element) using the Faraday effect is provided between the irradiation side polarizer and the observation side polarizer. Shown in Figure 8 As shown, the irradiation-side polarizer and the observation-side polarizer can be shared by a single polarizer (2 2) through the Faraday element (2 1). As described above, for example, when a polarizer having a concentric transmission axis is used as the irradiation side polarizer, the light transmitted through the sample surface without the observation sample reaches the observation side polarizer without being converted in polarization state. Therefore, it can be blocked by a polarizer having a radial transmission axis. As the optical rotator of the present invention, a known optical rotator can be used as long as it has a function of orthogonally crossing the polarization main axis direction. As a specific optical rotator, a Faraday rotator using magnetism (for example, JP 2 0 0 5 _ 2 8 3 6 3 5 publication, Toshiaki Sugawara “Lightwave optics” (see Corona, 1 998, page 2 2 3)) and other functions , Those composed of crystal or liquid crystal. That is, the polarization microscope of the embodiment shown in FIG. 8 includes a light source; a first polarizer that transmits light from the light source, and whose transmission axis is provided radially or concentrically; and the first polarizer. An observation sample stage on which a sample irradiated with light that has passed through is irradiated; light transmitted through the sample mounted on the observation sample stage, or light reflected from the sample mounted on the observation sample stage is transmitted; A lens; a light rotator that transmits the light transmitted through the objective lens; a polarization rotator that orthogonally crosses the polarization main axis direction; and a second rotator that transmits the light transmitted through the optical rotator and has a transmission axis similar to that of the first polarizer. The present invention relates to a polarizing microscope comprising: a polarizer;

In other words, by providing an optical rotator, the plane of polarization is shifted by 90 degrees, so the function of the polarizing microscope described above can be achieved with one type (preferably one) of polarizers. In other words, “a second polarizer having a transmission axis similar to that of the first polarizer” means, for example, that the first polarizer is a polarizer in which the transmission axis is provided concentrically around the optical axis. In this case, the polarizers may be the same polarizers, or the transmission axes may be provided concentrically around the optical axis, and the first polarizer may be provided radially around the optical axis. In the case of a polarizer, it may be the same polarizer or a polarizer whose transmission axis is provided radially around the optical axis. However, the Faraday rotator using magnetism reflects the light that has been transmitted through the Faraday rotator, and then reflects it again from the opposite side. When transmitted, it has the property of rotating twice. On the other hand, in the case of an optical rotator made of crystal or liquid crystal, once the optical rotator is transmitted and the optical rotator is transmitted from the opposite side, the optical rotation is reversed in the opposite direction to that transmitted from the forward side. Disappear. Therefore, it is preferable to use a Faraday rotator that uses magnetism when the irradiation light from the sample and the observation light from the sample pass through the same path as in a reflection microscope. On the other hand, any type of optical rotator can be used in a transmission-type polarization microscope in which the path between the irradiation light and the observation light is completely separated. In other words, it is preferable to use a Faraday rotator in a reflective polarization microscope as shown in Fig. 8.

[0041] Such a polarization microscope also includes a light source; a first polarization that transmits light from the light source, the transmission axis is provided radially around the optical axis or concentrically around the optical axis. An optical sample that transmits light transmitted through the first polarizer, an optical rotator that orthogonally crosses the direction of the principal axis of polarization, an observation sample stage that mounts a sample irradiated with the light transmitted through the optical rotator, and the observation sample base An objective lens that transmits light that has passed through the sample mounted on the sample, or light that has been reflected from the sample mounted on the observation sample stage; and the first polarizer that transmits light that has passed through the optical rotator. A polarization microscope comprising: a second polarizer having a similar transmission axis;

[0042] Hereinafter, it will be described how the light passing through the concentric or radial polarizer arranged at the pupil position of the condenser lens in the front stage of the sample is affected by the light reaching the image plane. The light beam that has passed through the entire surface of the condensing lens 曈 in the same direction is collected at one point on the image plane. Therefore, the light that illuminates a point on the image plane is a collection of light that has passed through all the surfaces of concentric or radial polarizers, and is light of any polarization orientation. When no object is present on the image plane, these lights reach radial or concentric polarizers arranged at the pupil position of the objective lens, and these polarizers are orthogonal to the polarization directions of the respective rays. Since it has a transmission axis, all light is blocked.

[0043] On the other hand, when a scatterer is present on the sample surface, the light beam that has passed through one point of the condenser lens pupil position is incident on the pupil plane of the objective lens (ie, the Fourier plane) after entering the scatterer at one point. Forms a light beam with a broad spread. Below, the sample has birefringence In other words, in order to consider the case where the light beam that has passed through the sample has a polarization component that is orthogonal to that before the sample passage, two states are considered: when the polarization orientation does not change before and after passing through the sample and when it is orthogonal. All states can be expressed as a combination of these two states.

First, let us consider the case where the polarization orientation does not change before and after passing through the sample. The component light beam penetrating the sample in a straight line is a radial ray placed at the pupil position of the objective lens, and at the point where it reaches the concentric polarizer, the polarization direction and the transmission axis of the polarizer are orthogonal. Blocked. However, since the diffracted light is generated according to the fineness of the sample in addition to the light beam penetrating the sample linearly, the light reaching the objective lens pupil position irradiates a wide area. In the region other than the center, the polarization direction of the light beam and the transmission axis deviate from orthogonal, and a component that is not blocked is generated according to the amount of deviation. In addition, the amount of deviation between the polarization direction of the light beam and the orthogonal direction of the polarizer transmission axis increases as the spread of the light beam increases, that is, as the component away from the center of the light beam increases. Furthermore, the spread of the luminous flux increases as the spatial frequency component of the scatterer increases, that is, as the scatterer becomes finer. Therefore, it can be seen that the non-blocking component increases as the sample becomes finer. When the sample is sufficiently fine, that is, when the diffracted light from the sample spreads over the entire objective lens pupil position, the transmittance is 50%. This is shown in Fig. 9. Figure 9 is a graph showing the relationship between the transmittance and the spatial frequency component of the sample when there is no polarization conversion by the sample.

Next, let us consider the case where the polarization orientation changes 90 degrees before and after passing through the sample. In this case, the light beam penetrating the sample in a straight line passes through 100% because it is polarized parallel to the transmission axis of the polarizer at the objective lens pupil position. As the sample becomes smaller, diffracted light is present around the light beam, resulting in components that do not transmit. In other words, the finer the sample, the more the blocking component increases. If the sample is sufficiently fine, the diffracted light from the sample spreads to the entire objective lens pupil position, and the transmittance is 50%. This is shown in FIG. Figure 10 is a graph showing the relationship between the transmittance and the spatial frequency component of the sample when the polarization orientation is changed by 90 degrees depending on the sample. It is.

[0045] From the above considerations, when there is nothing on the sample surface, a complete dark area is obtained, and when the object on the sample surface is sufficiently fine, regardless of whether the object has birefringence or not, it is 0. On the other hand, if the object is perfectly uniform, the transmittance corresponding to the birefringence of the object can be obtained. Therefore, an observation image having sensitivity corresponding to the fineness of the sample can be obtained not only by the presence or absence of birefringence.

[0046] A preferred embodiment of the polarizing microscope of the present invention includes a condensing lens that collects light from the light source between the light source and the first polarizer; Between the light source and the observation sample, disposed at a pupil position of the condenser lens; and the second polarizer is disposed at a pupil position of the objective lens; This relates to a polarizing microscope. In this specification, “pupil position of condensing lens” means the focal position of the condensing lens. On the other hand, “the pupil position of the objective lens” means the focal position of the objective lens.

[0047] In the polarization microscope of the present invention according to this aspect, by arranging a polarizer having a rotationally symmetric polarization axis at the pupil position of the condenser lens and the objective lens, or at a position conjugate with them, a straight line in all directions. Because the light with the same polarization mixed is incident on the sample, an observation image with no direction dependency can be obtained with a single observation. In addition, in this polarizing microscope, when the sample surface is a uniform transparent body, the light that has passed through a certain point of the concentric polarizer placed at the front stage of the observation sample is reflected by the radial polarizer placed at the rear stage of the observation sample. It is blocked by gathering at one corresponding point. On the other hand, if the observed sample has non-uniform components, more components are transmitted depending on the heterogeneity. Therefore, the smaller the inhomogeneity point in the observation sample is, the more the transmittance tends to increase, and an observation image that emphasizes high-frequency components as a whole can be obtained. Therefore, the polarization microscope according to this mode is suitable for observing minute defects, scratches, and fibrous structures.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples. In addition, the present invention is a well-known technology. Therefore, modifications can be made as appropriate, and known techniques can be incorporated as appropriate.

Example 1

[0049] 1. Substrate creation

A substrate for making a polarizer was prepared. Specifically, the quartz substrate was subjected to ion beam exposure, and a plurality of rectangular irregularities were provided so as to be concentric. The obtained substrate is shown in Fig. 11. In other words, Fig. 11 is a conceptual diagram of the board obtained in Example 1. The uneven width should be about half the normal wavelength, and the depth should be about half the wavelength.

[0050] Specifically, a self-cloning photonic crystal of 3; 0 ₂ and ₃ ₂ 0 ₅ was prepared using a quartz substrate provided with a plurality of concentric grooves. 40 layers were stacked with a substrate pitch of 2 3 2 nm, 3 10 ₂ 5 8 mm, and Ta ₂ O ₅ 8 1 nm. In this way, it was possible to obtain a polarizer that transmits only polarized light having an electric field component parallel to the unevenness at a wavelength of 520 to 50 nm (with an extinction ratio of 40 dB or more). We also manufactured a polarizer using a quartz substrate with a plurality of grooves extending radially from the center. This polarizer also had a radial transmission axis.

[0051] —On the other hand, using the same material, manufacture 2 7 layers of polarizers with substrate pitch of 2 45 nm, S i 0 ₂ of 1 45 nm and Ta ₂ 0 ₅ of 1 2 5 nm did. It was possible to obtain a polarizer that transmitted only polarized light having an electric field component perpendicular to the unevenness at a wavelength of 520 to 5500 nm. A polarizer having an extinction ratio of 40 dB or more was obtained. When the substrate groove is concentric, a polarizer with a radial transmission axis can be obtained. When a substrate with a radial groove is used, a polarizer with a concentric transmission axis can be obtained.

[0052] 2. Film-forming process

Using the substrate shown in Fig. 11, film formation was performed by the autocloning method. Specifically, the substrate shown in Fig. 11 is installed in the sputtering equipment,

(a) Deposition of deposited particles, (b) Plasma etching with Ar ions, and (c) Re-adhesion of surface constituent particles popped out by etching are carried out in a balanced manner. Triangular wave shape outermost layer Continued to maintain. Figure 12 shows a schematic diagram of the equipment used for autocloning and a schematic diagram of the autocloning method. Incidentally, a film was formed and silicon oxide tantalum dioxide (T a ₂ O _s) alternately. Figure 13 shows a conceptual diagram of the obtained polarizer. Figure 14 shows a photograph replacing the drawing of the obtained polarizer. As shown in Fig. 14, a polarizer was actually obtained based on this method.

[0053] 3. Characterization

The characteristics of the obtained polarizer were measured. Figure 15 is a graph replacing the drawing showing the spectral characteristics evaluation results of the prototype self-cloning photonic crystal polarizer. For the measurement, a measurement sample with linear grooves was used, which was formed at the same time as a substrate having concentric grooves. The TE wave with the electric field vibration component parallel to the concavo-convex groove shows a transmittance of 0.1% or less in the band below 500 nm, and the TM wave with the electric field vibration component orthogonal to the concavo-convex groove It shows a high transmittance of 90% or more in the band above nm, indicating that it has a high polarization separation function. Note that the band operating as a polarizer can be adjusted in various ways by changing the pitch of the concavo-convex grooves and the lamination period of the multilayer film. From the above data, it is clear that the prototype polarizer with concentric grooves has realized a polarization function with concentric cut-off axes and radial transmission axes.

[0054] 4. Simulation

Figure 16 shows the results of simulating the images obtained when scatterers of various shapes are placed on the observation surface with the polarizing microscope of the present invention. Figure 16 (a) shows the images observed with a polarizing microscope for scatterers with the same edge sharpness but different sizes. Figure 16 (b) shows the images observed with a polarizing microscope for scatterers of the same size but different edge sharpness. From Fig. 16 (a), it can be seen that the brightness of the obtained image increases as the object becomes smaller if the polarizing microscope of the present invention is used. From Fig. 16 (b), it can be seen that the sharper the edge, the higher the brightness of the obtained image.

Industrial applicability

[0055] The polarizer of the present invention is widely used not only in a polarizing microscope but also in the optical element industry. Can be used. On the other hand, the polarizing microscope of the present invention is widely used as a microscope because it is effectively used for observation of biological samples.

Brief Description of Drawings

[Fig. 1] Fig. 1 is a diagram showing the direction of the transmission axis in a polarizer in which the transmission axes are concentrically arranged.

[Fig. 2] Fig. 2 is a diagram showing the direction of the transmission axis in a polarizer whose transmission axis is arranged radially from one point.

[Fig. 3] Fig. 3 shows a schematic diagram of a polarizer having transmission axes in concentric or radial fashion using self-cloning photonic crystals. Figure 3 (a) shows an example of a polarizer with transmission axes concentrically arranged. Figure 3 (b) shows an example of a polarizer with a transmission axis that radiates from one point. Figure 3 (c) shows an example of a polarizer whose transmission axis is arranged in multiple stages radially from the center of the polarizer.

[Figure 4] Figure 4 shows an example of a self-cloning photonic crystal.

[Fig. 5] Fig. 5 is a schematic diagram of a wire-and-grid polarizer.

FIG. 6 shows an example of the configuration of a polarizing microscope.

[FIG. 7] FIG. 7 is a diagram showing an example of a polarization microscope in which an optical rotator composed of a crystal rotator or liquid crystal is inserted between an irradiation side polarizer and an observation side polarizer.

[Fig. 8] Fig. 8 shows an example of a polarizing microscope in which a rotator (Faraday element) using the Faraday effect is provided between the irradiation side polarizer and the observation side polarizer.

[Fig. 9] Fig. 9 is a graph showing the relationship between the transmittance and the spatial frequency component of the sample when there is no polarization conversion by the sample.

[Fig. 10] Fig. 10 is a graph showing the relationship between the transmittance and the spatial frequency component of the sample when the polarization orientation is converted by 90 ° by the sample.

[Fig. 1 1] FIG. 11 is a conceptual diagram of the substrate obtained in Example 1. FIG.

[Fig. 12] Fig. 12 shows a schematic diagram of the equipment used for autocloning and a schematic diagram of the autocloning method. Silicon dioxide and tantalum oxide (T a ₂ 0 ₅

) Were alternately formed.

[Figure 13] Figure 13 shows a conceptual diagram of the obtained polarizer. [Fig.14] Fig.14 shows a photograph replacing the drawing of the obtained polarizer.

[Fig. 15] Fig. 15 is a graph instead of a drawing showing the spectral characteristics evaluation results of the prototype self-cloning photonic crystal polarizer.

[Fig. 16] Fig. 16 shows the results of simulating the images obtained when various shapes of scatterers were placed on the observation surface in the polarizing microscope of the present invention. Figure 16 (a) shows the images observed with a polarizing microscope for scatterers with the same edge sharpness but different sizes. Figure 16 (b) shows the images observed with a polarizing microscope for scatterers of the same size but different edge sharpness.

Explanation of symbols

1 1 Polarizing microscope

1 2 Lamphouse

1 3 Condensing lens

1 4 Mira

1 5 Irradiation side polarizer

1 6 Condenser lens

1 7 Observation sample

1 8 Objective lens

1 9 Observation side polarizer (analyzer)

2 0 Eyepiece

2 1 Faraday element

Claims

The scope of the claims

[1] A polarizer in which transmission axes are provided concentrically.

[2] The polarizer according to [1], comprising a self-cloning photonic crystal.

[3] A polarizer whose transmission axis is provided radially from one point.

[4] The polarizer according to [3], comprising a self-cloning photonic crystal.

[5] with light source;

A first polarizer through which light from the light source is transmitted, the transmission axis being provided concentrically around the optical axis;

An observation sample stage on which a sample irradiated with light transmitted through the first polarizer is mounted; light transmitted through the sample mounted on the observation sample stage, or reflected from a sample mounted on the observation sample stage Light is transmitted through the objective lens;

A second polarizer in which light transmitted through the objective lens is transmitted, the transmission axis being provided radially around the optical axis;

A polarizing microscope.

[6] A condensing lens for condensing light from the light source is provided between the light source and the first polarizer;

The first polarizer is:

Between the light source and the observation sample and disposed at a pupil position of the condenser lens;

The second polarizer is:

Arranged at the pupil position of the objective lens;

The polarizing microscope according to claim 5.

[7] with light source;

A first polarizer that transmits light from the light source, and whose transmission axis is provided radially about the optical axis;

An observation sample stage carrying a sample irradiated with light transmitted through the first polarizer; An objective lens that transmits light transmitted through a sample mounted on the observation sample stage or light reflected from a sample mounted on the observation sample stage;

Light transmitted through the objective lens is transmitted; and a second polarizer provided with a transmission axis concentrically centered on the optical axis;

A polarizing microscope.

[8] A condensing lens for condensing light from the light source is provided between the light source and the first polarizer;

The first polarizer is:

The second polarizer is:

Arranged at the pupil position of the objective lens;

The polarizing microscope according to claim 7.

[9] with light source;

A first polarizer that transmits light from the light source, the transmission axis is provided radially around the optical axis or concentrically around the optical axis;

An optical rotator that transmits the light transmitted through the objective lens and orthogonally crosses the direction of the polarization main axis;

A second polarizer having a transmission axis similar to that of the first polarizer, through which the light transmitted through the optical rotator is transmitted;

A polarizing microscope.

[10] A condensing lens for condensing light from the light source is provided between the light source and the first polarizer;

The first polarizer is:

Arranged between the light source and the observation sample and at the pupil position of the condenser lens Is;

The second polarizer is:

Arranged at the pupil position of the objective lens;

The polarizing microscope according to claim 9.

[1 1] The polarizing microscope according to claim 9, wherein the first polarizer and the second polarizer are the same polarizer.

[12] with a light source;

A light transmissive element through which the light transmitted through the first polarizer is transmitted;

An observation sample stage carrying a sample irradiated with light transmitted through the optical rotator;

An objective lens that transmits light transmitted through a sample mounted on the observation sample stage or light reflected from a sample mounted on the observation sample stage;

A polarizing microscope.

[13] A condensing lens for condensing light from the light source is provided between the light source and the first polarizer;

The first polarizer is:

The second polarizer is:

Arranged at the pupil position of the objective lens;

The polarizing microscope according to claim 12.

14. The polarizing microscope according to claim 12, wherein the first polarizer and the second polarizer are the same polarizer.

[15] Polarized light with concentric transmission axes at the pupil position of the condenser lens and the pupil position of the objective lens A microscope comprising a polarizer and a polarizer having a radial transmission axis, wherein a finer structure can obtain a higher resolution image.