JP4780483B2 - Sample table for laser microscope and laser microscope - Google Patents

Description

  The present invention relates to a laser microscope, and more particularly, to a laser microscope that facilitates observation of an object to be measured using light reflection.

  Laser microscopes are known in which laser light is incident on a sample and the sample is optically observed by laser light reflected or scattered by the sample. FIG. 10 is a diagram for explaining a schematic configuration of a conventionally known laser microscope. This configuration is a general configuration example.

  The laser microscope 101 reflects and scans the laser beam output from the laser oscillator 2 by the movable reflector 3 and irradiates the sample 200 with the incident laser beam 106. The reflected laser beam 107 reflected by the sample 200 is detected by the detector 5. The reflected laser beam 107 has unevenness information on the surface of the sample 200, and the sample 200 can be optically observed by a detection signal obtained by detecting the reflected laser beam 107.

  The optical axes of the incident laser beam 106 and the reflected laser beam 107 are on the same axis, and the reflected laser beam 107 from the sample 200 is branched to the beam splitter 4 after passing through the same axis as the incident light and reaches the detector 5. The sample 200 is placed on a planar sample stage 100.

  In the laser microscope having the above-described configuration, when the incident angle of the incident laser beam on the sample is increased, the laser beam is scattered, so that the amount of reflected laser beam reaching the detector is reduced, and a clear image cannot be obtained. is there.

  FIG. 11 is a diagram for explaining the reflection state of the reflected laser light on the sample. Here, the case of a sphere as a sample is shown.

  In FIG. 11A, the incident laser beam 6 a is shown in a state of being incident perpendicular to the surface of the sample 20. As described above, when the incident laser beam 6a is incident on the sample surface perpendicularly, the reflected laser beam 7a reflected on the sample surface is reflected in the opposite direction to the incident direction and returns on the same axis. Can be detected.

  On the other hand, the incident laser beams 6b and 6c are shown incident on the surface of the sample 20 at large incident angles θb and θc. As the incident angle θ to the sample 20 increases, the reflection angle increases as shown in the reflected laser beams 7b and 7c, and the degree of scattering also increases. Therefore, the reflected laser beam that returns coaxially with the incident laser beam decreases. Here, the incident angle θ is an angle formed by the incident direction and the vertical direction of the measurement surface.

  FIG. 11B shows an angle range in which the reflected laser beam returns coaxially with the incident laser beam. When the sample is a sphere, the laser beam incident on the narrow angle range 300 centered on the central axis in the vertical direction of the sphere returns in the coaxial direction, but the incident laser beam incident outside this angle range is in the coaxial direction. It does not return and does not contribute to optical observation of the sample.

  Even within the range of the angle range 300, the amount of light returning to the coaxial direction is greatly reduced at an angle portion far from the central axis of the sphere. Therefore, although the vicinity of the center of the sphere can be observed, a sufficient amount of light cannot be obtained as it becomes the outer periphery, so that the outer shape of the sample is observed only unclearly.

  When the sample is a sphere, the incident angle of the measurement surface increases steeply with distance from the central axis, and the reflection surface is parallel to the incident direction near the maximum diameter (the equator part of the sphere). The reflected laser light does not return and no image is formed.

  This means that the outer periphery of the sphere cannot be observed, and the function as a microscope cannot be achieved. FIG. 12 is an example of the observation image, and the image of the outer peripheral portion of the sphere is unclear.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems and obtain a clear image even at a portion where an incident angle of incident laser light with respect to a measurement surface of a sample is large. Another object of the present invention is to increase the amount of reflected laser light toward the detector even at a portion where the incident angle of the incident laser light with respect to the measurement surface of the sample is large.

  In the present invention, a laser beam scattered from the sample in a direction other than the optical axis direction is reflected again by the sample stage, and the amount of light returning to the detector direction is increased, thereby obtaining a clear image.

  The sample stage for a laser microscope according to the present invention is a sample stage provided in a laser microscope for optically observing a sample with reflected laser light from the sample. The sample is placed on the optical axis of incident laser light, and this sample is also provided. The mounting surface for mounting has a concave reflecting surface.

  Of the incident laser light, the laser light having a small incident angle with respect to the sample is reflected by the sample surface and returned to the optical axis direction to form an image with the detector. On the other hand, the laser beam having a large incident angle with respect to the sample has a large reflection angle on the sample surface and a large degree of scattering, so that the amount of light returning directly in the optical axis direction is reduced.

  Reflected laser light and scattered light reflected at a large reflection angle on the sample surface are reflected by the reflecting surface of the mounting surface. Since the reflecting surface of the mounting surface is concave, this reflected laser light or scattered laser light is returned to the optical axis direction to increase the amount of light detected by the detector. As a result, the sharpness of the image that is unclear due to the small amount of light increases.

  When the sample is placed on the placement surface of the sample stage, the incident angle at which the reflected laser light or scattered laser light reflected or scattered by the sample surface enters the placement surface changes. Although it is desirable to set the curvature of the concave surface of the mounting surface according to the size and shape of the sample to be measured, the present invention returns all reflected laser light or scattered reflected laser light in the optical axis direction, It is not intended to be incident on the detector, but is intended to increase the amount of light that is returned from the reflected laser light or scattered laser light that has been conventionally scattered in the optical axis direction.

  Therefore, by setting the assumed measurement object as a reference sample and setting the curvature of the concave surface of the mounting surface according to this reference sample, the degree of increase in the amount of light can be increased even when the size of the sample changes. Although it is different, the reflected laser light and scattered laser light that have been scattered can be returned to the optical axis direction to increase the amount of light.

  When the size of the sample is smaller than the assumed reference sample and the effect of increasing the amount of light cannot be greatly expected, the adjustment member can be used to align the sample with the position of the reference sample. The adjusting member adjusts the distance between the sample and the mounting surface, and adjusts the position of the incident point where the incident laser beam enters the sample and the position of the incident point where the reflected laser beam enters the mounting surface. As a result, even when the sample is small, reflected laser light and scattered laser light comparable to the reference sample can be returned in the optical axis direction.

  Further, the mounting surface can be symmetric in the entire circumferential direction with respect to the optical axis. Thereby, the laser light reflected or scattered on the outer periphery of the sample can be returned to the optical axis direction.

  Further, the mounting surface can be axisymmetric with respect to an axial direction orthogonal to the optical axis. According to this mounting surface, the sample shape can be applied to the shape of a columnar body such as a cylinder, and the sample is placed on the mounting surface by aligning the axial direction of the mounting surface with the axial direction of the sample. Thus, with respect to the curved portion of the columnar body, it is possible to return the reflected laser light and scattered laser light, which have been conventionally scattered, to the optical axis direction and increase the amount of light detected by the detector.

  Further, the present invention is not limited to the sample stage, but also includes a laser microscope. The laser microscope is a laser microscope that optically observes a sample by reflected laser light from the sample, and includes a sample stage on which the sample is placed on the optical axis of incident laser light, and the sample on the sample stage is placed on the laser microscope. The surface is a concave reflecting surface.

  Further, in the laser microscope aspect of the present invention, a sample stage on which the sample is placed on the optical axis of the incident laser beam is provided, and the surface on which the sample is placed is a concave reflecting surface, and this reflection surface The surface can be configured to reflect the incident laser light on the back surface of the sample and provide an angle that reflects the reflected light reflected on the back surface of the sample in the optical axis direction.

  Furthermore, in the aspect of the laser microscope of the present invention, the first extraction means for extracting the image data of the placement surface from the measurement image data of the sample, and the placement obtained in advance from the extracted image data of the placement surface It is good also as a structure provided with the 2nd extraction means which subtracts surface image data and acquires the image data of the back surface of the sample contained in the said mounting surface image data.

  According to this aspect of the laser microscope, it is possible to detect an image near the back surface that could not be detected in the past. In particular, it is possible to acquire an image on the back surface side in the vicinity where the front surface is parallel to the incident laser light. This vicinity usually corresponds to the boundary of the sample when viewed from the incident light side, and an image on the back side where this boundary cannot be normally obtained can be observed.

  According to the present invention, a clear image can be obtained even at a portion where the incident laser light has a large incident angle with respect to the measurement surface of the sample.

  Further, the amount of reflected laser light can be increased toward the detector even at a portion where the incident angle of the incident laser light with respect to the measurement surface of the sample is large.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram for explaining a schematic configuration of a laser microscope of the present invention. The configuration of the laser microscope shown in FIG. 1 is substantially the same as the configuration of the conventional laser microscope shown in FIG.

  The laser microscope 1 reflects and scans the laser beam output from the laser oscillator 2 by the movable reflector 3 and irradiates the sample 20 with the incident laser beam 6. The reflected laser beam 7 reflected by the sample 20 is detected by the detector 5. The reflected laser light 7 has unevenness information on the surface of the sample 20, and the sample 20 can be optically observed by a detection signal obtained by detecting the reflected laser light 7.

  The optical axes of the incident laser light 6 and the reflected laser light 7 are on the same axis, and the reflected laser light 7 from the sample 20 is branched to the beam splitter 4 after passing through the same axis as the incident light and reaches the detector 5. The sample 20 is placed on the concave sample stage 10.

  Hereafter, each form of the sample stand of this invention is demonstrated using FIGS. FIG. 2 is a diagram for explaining a first embodiment of the sample table of the present invention, FIG. 3 is a diagram for explaining a second embodiment of the sample table of the present invention, and FIG. 4 is a diagram of the present invention. It is a figure for demonstrating the 3rd form of a sample stand, and FIG. 5 is a figure for demonstrating the 4th form of the sample stand of this invention.

  First, the 1st form of the sample stand of this invention is demonstrated using FIG. In the sample stage 10 of the first form, the placement surface 11 on which the sample 20 is placed has a concave shape. FIG. 2A shows the reflection state of the reflected laser light on the sample. Here, the case where the sample 20 is a sphere is shown.

  In FIG. 2A, the incident laser beam 6a is shown perpendicularly incident on the surface of the sample 20. FIG. As described above, when the incident laser beam 6a is incident on the sample surface perpendicularly, the reflected laser beam 7a reflected on the sample surface is reflected in the opposite direction to the incident direction and returns on the same axis. Can be detected. This optical path is the same as in FIG.

  On the other hand, the incident laser beams 6b and 6c are shown incident on the surface of the sample 20 at large incident angles θb and θc. As the incident angle θ to the sample 20 increases, the reflection angle increases and the degree of scattering increases as shown by the reflected laser beams 7b and 7c, and the reflected laser beam returning coaxially with the incident laser beam decreases. Here, the incident angle θ is an angle formed by the incident direction and the vertical direction of the measurement surface.

  In the sample stage 10 of the present invention, since the mounting surface 11 has a concave shape, the reflected laser light 7b1 of the incident laser light 6b incident at the incident angle θb is reflected by the mounting surface 11 to become reflected laser light 7b2. It proceeds in the optical axis direction of the optical system of the microscope. Similarly, the reflected laser beam 7c1 of the incident laser beam 6c incident at a larger incident angle θc is also reflected by the mounting surface 11 to become the reflected laser beam 7c2, and proceeds in the optical axis direction of the optical system of the laser microscope. become.

  FIG. 2B shows an angle range in which the reflected laser light returns coaxially with the incident laser light. When the sample 20 is a sphere, the laser light incident on the angle range 30 centered on the central axis in the vertical direction of the sphere returns to the coaxial direction. This angle range 30 is approximately 180 degrees. The outside of the angle range 30 is outside the angle range where the incident laser light is incident on the sample 20 and does not directly enter the surface of the sample 20.

  According to the first embodiment, the incident laser light that has entered the part of the sphere far from the central axis of the sphere does not return directly in the optical axis direction of the optical system, but is reflected by the mounting surface 11 of the sample stage 10. As a result, the optical system returns to the optical axis direction.

  As a result, the amount of light reaching the detector side also increases in the outer peripheral portion of the sample 20, and the sharpness of the image of the outer shape of the sample can be increased.

  Next, the 2nd form of the sample stand of this invention is demonstrated using FIG. Similar to the first embodiment, the sample stage 10 of the second embodiment includes a concave placement surface 11 and an adjustment member 12.

  The adjustment member 12 is a member that adjusts the distance between the sample 21 and the placement surface 11. For example, the adjustment member 12 supports the sample 21 at a position above the placement surface 11 and adjusts the incident relation of incident laser light. The adjusting member 12 adjusts the position of the incident point where the incident laser beam 6 is incident on the sample 10 and the position of the incident point where the reflected laser beam reflected by the sample 10 is incident on the mounting surface 11, thereby making the incident Adjust the incident relationship of laser light.

  For example, when the sample 21 has a smaller diameter than the sample 20 shown in FIG. 2 and the sample 21 is placed on the placement surface 11, the incident relation of the incident laser light changes, so that the reflection reflected by the sample 21 is reflected. The position and angle at which the laser beam is incident on the mounting surface 11 are greatly changed, and the reflected laser beam may not return to the optical axis direction (not shown).

  In the second embodiment of the present invention, when observing the small-diameter sample 21 as described above, the adjustment member 12 is placed on the placement surface 11, and the sample 21 is placed on the adjustment member 12. . Thereby, the positional relationship between the incident laser beam and the sample 21 is made the same as that in the case of the standard sample, and the reflected laser beam is returned to the optical axis direction.

  In FIG. 3, since the mounting surface 11 of the sample stage 10 has a concave shape and the sample 21 is mounted on the adjusting member 12, the reflected laser beam 7b1 of the incident laser beam 6b incident at the incident angle θb is It is reflected by the mounting surface 11 to become reflected laser light 7b2, and proceeds in the optical axis direction of the optical system of the laser microscope. Similarly, the reflected laser beam 7c1 of the incident laser beam 6c incident at a larger incident angle θc is also reflected by the mounting surface 11 to become the reflected laser beam 7c2, and proceeds in the optical axis direction of the optical system of the laser microscope. become.

  Next, a third embodiment of the sample stage of the present invention will be described with reference to FIG. Similar to the first embodiment, the sample stage 10 of the third embodiment includes a concave mounting surface 11. The concave shape provided in the mounting surface 13 of the third form is constituted by a plurality of annular inclined surfaces arranged concentrically. This concave shape can be formed using the surface of the Fresnel lens. According to this shape, the height of the sample stage 10 can be reduced.

  Next, the 4th form of the sample stand of this invention is demonstrated using FIG. In the sample stage 10 of the fourth embodiment, the mounting surface 14 can be axisymmetric with respect to an axial direction 15 orthogonal to the optical axis. According to this mounting surface 14, the shape of the sample 22 can be applied to the shape of a columnar body such as a cylinder.

  The sample 22 is placed on the placement surface 14 so that the axial direction 15 of the placement surface 14 and the axial direction 16 of the sample 22 are parallel to each other. As a result, it is possible to return the reflected laser light and scattered laser light that have been scattered in the axial direction of the columnar sample 22 in the axial direction, and increase the amount of light detected by the detector. The mounting surface 14 extending in the axial direction 15 may be formed on a part of the flat mounting surface.

  FIG. 6 is an example of the observation image, and the sharpness of the image can be increased also in the outer peripheral portion of the sphere.

  Next, an example of acquiring an image of the back surface of a spherical sample using the configuration of the present invention will be described with reference to FIGS.

  In the sample table 10, the mounting surface 11 on which the sample 20 is mounted has a concave shape as in the above-described embodiments. FIG. 7A shows the reflection state of the reflected laser light on the sample. Here, the case where the sample 20 is a sphere is shown.

  In FIG. 7A, the incident laser beam 6 a is shown in a state of being incident perpendicular to the surface of the sample 20. Thus, when the incident laser beam 6a is incident on the sample surface perpendicularly, as described above, the reflected laser beam 7a reflected on the sample surface is reflected in the opposite direction to the incident direction, so that it returns on the same axis and is detected. The instrument can detect a sufficient amount of light. This optical path is the same as in FIG.

  On the other hand, the incident laser beams 6d, 6e, and 6f are not incident on the surface of the sample 20.

  The incident laser beam d shows a state in which the surface of the sample 20 is grazed and directly incident on the mounting surface 11 of the sample table 10. The incident laser beam 6 d incident on the mounting surface 11 is reflected by the mounting surface 11, and the reflected laser beam 7 d 1 enters the back side of the sample 20. The reflected laser light 7d1 is reflected on the back surface of the sample 20, and the reflected laser light 7d2 is incident again on the mounting surface 11 and reflected, and returns to the optical axis side as reflected laser light 7d3.

  Further, the incident laser beams 6e and 6f incident on the mounting surface 11 are also reflected by the mounting surface 11 similarly to the incident laser light 6d, and the reflected laser beams 7e1 and 7f1 are incident on the back surface side of the sample 20. The reflected laser beams 7e1 and 7f are reflected on the back surface of the sample 20, and the reflected laser beams 7e2 and 7f2 are incident again on the mounting surface 11 and reflected, and return to the optical axis side as reflected laser beams 7e3 and 7f3.

  These reflected laser beams 7d3, 7e3, and 7f3 include image information on the back side of the sample 20.

  FIG. 7B shows a reflection state of the reflected laser light reflected on the back surface of the sample. The reflected laser light incident on the mounting surface 11 of the sample table 20 and reflected toward the back surface side of the sample 20 is reflected by the back surface of the sample 20 and then reflected again by the mounting surface 11 and returned to the optical axis side. Is done. Thereby, image information can be acquired also about the back surface of the sample to which the incident laser beam does not reach.

  The configuration and procedure for acquiring the image data of the back surface of the sample will be described using the flowchart of FIG. 8 and the explanatory diagram of FIG.

  First, an image is acquired in a state where no sample is placed on the sample stage, and image data A of the surface shape of only the placement surface is obtained (S1).

  Next, an image is acquired with the sample placed on the sample stage, and measurement data B is acquired. Here, in the image obtained by the detector, a region where the sample exists is a measurement target region c, and a region other than the measurement target region c is a placement surface region d. The acquired measurement data B includes data C of the measurement target area c and data D of the placement surface area d (S2).

  The data C of the measurement target area c and the data D of the placement surface area d are separated from the measurement data B acquired in the step S2. This separation of data can be performed by extracting the boundary portion of the measurement target region c by performing image processing for extracting the edge of the measurement data B, for example. Here, the data D of the mounting surface area d includes the surface data E of the mounting surface and the back data F of the sample (S3).

  The data C separated in the step S3 is taken out (S4), and the placement surface data E is obtained by subtracting the data C of the measurement target area c from the image data A of the placement surface only obtained in advance (S5). ).

  Since the data D includes the surface data E of the mounting surface and the back surface data F of the sample, the back surface data F is acquired by subtracting the mounting surface data E acquired in step S5 from this data D (S7). ).

  In the image data acquired in the step S7, the coordinate position of the back surface image of the sample depends on the shape of the mounting surface. Therefore, a correspondence relationship between the image data and the back surface position of the sample is obtained in advance, and based on this correspondence relationship. The coordinates are converted to form image data at the back surface position of the sample (S8) and display (S9).

It is a figure for demonstrating schematic structure of the laser microscope of this invention. It is a figure for demonstrating the 1st form of the sample stand of this invention. It is a figure for demonstrating the 2nd form of the sample stand of this invention. It is a figure for demonstrating the 3rd form of the sample stand of this invention. It is a figure for demonstrating the 4th form of the sample stand of this invention. It is an example of the observation image by the laser microscope of this invention. It is a figure for demonstrating the image acquisition of the back surface of the spherical-shaped sample using the structure of this invention. It is a flowchart for demonstrating the image acquisition of the back surface of the spherical-shaped sample using the structure of this invention. It is a procedure figure for demonstrating the image acquisition of the back surface of the spherical-shaped sample using the structure of this invention. It is a figure for demonstrating schematic structure of the laser microscope conventionally known. It is a figure for demonstrating the reflective state of the reflected laser beam on a sample. It is an example of the observation image by the conventional laser microscope.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Laser microscope, 2 ... Laser oscillator, 3 ... Movable reflector, 4 ... Beam splitter, 5 ... Detector, 6 ... Incident laser beam, 7 ... Reflected laser beam, 10 ... Sample stand, 11 ... Mounting surface, 12 ... Adjusting member, 13 ... Placement surface, 14 ... Placement surface, 15,16 ... Axis, 20, 21,22 ... Sample, 30 ... Angular range, 100 ... Sample stage, 101 ... Laser microscope, 106 ... Incident laser beam 107: Reflected laser light, 200: Sample, 300: Angular range.

Claims (6)

In a laser microscope that optically observes a sample with reflected laser light from the sample, the sample stage provided in the laser microscope,
A sample stage for a laser microscope, wherein a sample is placed on an optical axis of incident laser light, and a placement surface on which the sample is placed has a concave reflecting surface.   The mounting surface adjusts the distance between the sample and the mounting surface, and adjusts the position of the incident point where the incident laser beam enters the sample and the position of the incident point where the reflected laser beam enters the mounting surface. The sample stage for a laser microscope according to claim 1, further comprising an adjusting member.   2. The laser microscope sample stage according to claim 1, wherein the mounting surface is symmetrical in the entire circumferential direction with respect to the optical axis.   The sample stage for a laser microscope according to claim 1, wherein the placement surface is axially symmetric with respect to an axial direction orthogonal to the optical axis. In a laser microscope that optically observes a sample with reflected laser light from the sample,
A sample stage for placing the sample on the optical axis of the incident laser beam;
The laser microscope characterized in that the surface of the sample stage on which the sample is placed is a concave reflecting surface. In a laser microscope that optically observes a sample with reflected laser light from the sample,
A sample stage for placing the sample on the optical axis of the incident laser beam;
The surface of the sample table on which the sample is placed is a concave reflecting surface,
The laser microscope characterized in that the reflection surface has an angle that reflects the incident laser light on the back surface of the sample and reflects the reflected light reflected on the back surface of the sample in the optical axis direction.