JP4884764B2 - Laser microscope - Google Patents

Description

  The present invention relates to a laser microscope that has a measurement optical system and an observation optical system, takes a two-dimensional image and a confocal image of a sample, and measures the cross-sectional shape of the sample.

  A laser microscope is known in which the surface of a sample to be observed is two-dimensionally scanned with a laser beam and reflected light from the sample is received by a linear image sensor (see, for example, Patent Document 1). In this laser microscope, the laser beam is deflected in the main scanning direction by an acousto-optic device, deflected in the sub-scanning direction using a galvanometer mirror, focused in a spot shape by an objective lens, and projected onto the sample surface. . The reflected beam from the sample surface is collected by an objective lens, received by a linear image sensor having a plurality of light receiving elements arranged in the main scanning direction, and signal processing is performed on video output from the linear image sensor. The video signal is output.

  The above-mentioned laser microscope can capture a high-resolution image, displays the captured two-dimensional image on a monitor, and is also used as a measurement device that measures the size of the actual image of the sample from the image on the monitor. ing. For example, in a semiconductor device manufacturing process, in order to inspect whether or not the width of an electrode formed on a substrate is formed to a predetermined width, a two-dimensional image captured by a laser microscope is displayed on a monitor, and the monitor The electrode width dimension is measured above.

  In addition, while moving the objective lens in the optical axis direction, the sample surface is scanned one-dimensionally with a laser beam, and the cross-sectional shape of the sample is measured by detecting the position in the optical axis direction where the luminance value of each pixel is maximum. It is also used as a cross-sectional shape measuring device (for example, see Patent Document 2). As described above, the laser microscope is widely used for measuring a dimension of a predetermined portion of the sample as well as capturing a two-dimensional image of the sample.

Japanese Patent Laid-Open No. 62-18179 JP-A-8-160306

  The laser microscope described above has a high resolution and can be used for measuring the appearance of a sample. However, since the main scanning is performed using an expensive acoustooptic device, there is a drawback that the manufacturing cost is high. In addition, when the beam is deflected using an acousto-optic device, it has been pointed out that the adjustment work of the incident angle of the laser beam is complicated. On the other hand, a laser microscope has also been proposed in which a line-shaped light beam is generated using a mercury lamp and an aperture having a slit opening, and a sample is scanned with the line-shaped light beam. However, since the mercury lamp is expensive, the manufacturing cost of the laser microscope is significantly increased. Further, since the mercury lamp is large, there is a drawback that the laser microscope itself is enlarged.

  In addition, since the depth of focus of the laser microscope is shallow, when observing an uneven sample surface, there is a drawback that only an image of a part in focus is captured, and an image of an unfocused part is not displayed. . For this reason, when setting the visual field which should be observed, there exists a fault which becomes difficult to set visual field. In this case, move the objective lens in the direction of the optical axis to capture a large number of images, find the maximum brightness value for each pixel, form a 2D image with the maximum brightness value, and set the field of view from the obtained 2D image. The method to do is known. However, in this method, a large number of two-dimensional images must be captured, and there is a drawback that it takes a long time to capture a two-dimensional image.

  Further, as described in Patent Document 2, in the method of measuring the cross-sectional shape by scanning the laser beam one-dimensionally in the main scanning direction with a galvano mirror while changing the distance between the objective lens and the sample, Z Since both the scanning in the axial direction and the scanning in the main scanning direction need to be performed, there is a drawback that it takes time to measure the cross-sectional shape.

  Further, as described in Patent Document 2, there has been proposed a laser microscope using a confocal optical system as a measurement optical system and having a measurement optical system and an observation optical system. In this laser microscope, the confocal optical system and the observation optical system are coupled by a half mirror. However, when a half mirror is used as an optical system for coupling the two optical systems, the observation light enters the linear image sensor, causing crosstalk, and an image with a high noise level is formed. For this reason, there is a drawback that the quality of the one-dimensional image output from the measurement optical system is lowered and the measurement accuracy is lowered.

  Furthermore, for example, when observing a sample surface with an uneven surface, such as an LSI, if an image is taken using a normal two-dimensional CCD camera, a sharp image is captured at the in-focus area, but from the in-focus position. An unclear image is picked up at the removed part. The request to observe the focused image for the entire field of view is not met. Furthermore, there is a strong demand for measuring the cross-sectional shape or cross-sectional profile of a sample with a rough surface. For such a sample, if a two-dimensional image and a confocal image can be taken using a single measuring apparatus and the cross-sectional shape can be measured, a laser microscope having high versatility can be realized.

An object of the present invention is to realize a laser microscope that can two-dimensionally scan a sample surface without using an acousto-optic element or a mercury lamp.
Another object of the present invention is to provide a laser microscope that can two-dimensionally scan the surface of a sample without using an acoustooptic device and can easily set the field of view to be observed.
Furthermore, another object of the present invention is to provide a laser microscope that can further reduce the measurement time required for measuring the cross-sectional shape of a sample.
Another object of the present invention is to provide a laser microscope capable of accurately measuring a cross-sectional profile or cross-sectional shape of a sample in a laser microscope having a measurement optical system and an observation optical system.
Furthermore, another object of the present invention is to provide a laser microscope capable of capturing a two-dimensional image and a confocal image of a sample and a cross-sectional shape.

A laser microscope according to the present invention includes a confocal optical system that captures a confocal image of a sample to be observed, an observation optical system that illuminates the sample with observation light and captures a two-dimensional image of the sample, and the confocal optical system. In a laser microscope having a signal processing device that performs signal processing on the image signal output from the image signal output from the observation optical system and outputs a video signal,
The confocal optical system includes a line-shaped light beam generating unit that converts a laser beam into a non-coherent line-shaped light beam extending in a first direction, and the line-shaped light beam orthogonal to the first direction. Beam deflecting means for periodically deflecting in the second direction, an objective lens for projecting the line-shaped light beam toward the specimen to be observed, means for changing the relative distance between the objective lens and the specimen, A position detection unit that detects a relative distance between the objective lens and the sample as position information in the optical axis direction and a plurality of light receiving elements arranged in a direction corresponding to the first direction, and emits from the sample. A linear image sensor that receives line-like reflected light and outputs an image signal ;
The observation optical system includes an illumination light source that generates observation light, a coupling optical system that couples observation light emitted from the illumination light source to the optical path of the objective lens, and reflected light from the sample to the objective lens and the cup. A two-dimensional imaging device that receives light via a ring optical system,
The signal processing circuit includes means for detecting a maximum luminance value of each pixel for a plurality of two-dimensional images captured while changing a relative distance between the objective lens and the sample, and a maximum luminance value of each pixel of the two-dimensional image. A first image memory for storing the image, a Z-axis memory for storing a position in the optical axis direction at which the maximum luminance value of each pixel is generated, and a second image information for storing the two-dimensional image information output from the two-dimensional imaging device. Two image memories,
The line-shaped light beam is composed of light in the ultraviolet or near ultraviolet wavelength region, and the observation light is composed of white light in the visible region,
The coupling optical system is configured by a sharp cut filter that transmits light constituting the line-shaped light beam and reflects the observation light,
The laser microscope outputs a two-dimensional image of a sample, a two-dimensional confocal image, a three-dimensional image, a cross-sectional shape image, or a composite image in which the cross-sectional shape image is superimposed on the two-dimensional image .

  In the present invention, since a coherent laser beam is converted into a non-coherent line-shaped light beam by a micromirror device, a one-dimensional image of a sample can be taken without using an acousto-optic element or a mercury lamp. Cost is significantly reduced. Furthermore, when taking multiple one-dimensional images of the sample while changing the relative distance between the sample and the objective lens, the line-shaped light beam only needs to be displaced in the direction of the optical axis. Can be greatly shortened. On the other hand, in the laser microscope described in Patent Document 2, while moving the objective lens to the optical axis, a laser beam is periodically deflected by a vibrating mirror to capture a plurality of one-dimensional images of the sample. . However, this scanning method has a limitation in measurement time because the laser beam must be scanned.

  In a preferred embodiment of the laser microscope according to the present invention, the line-shaped light beam generator includes a laser light source, a micromirror device having a plurality of micromirror elements arranged in a two-dimensional matrix on the light incident surface, and a micromirror element. A drive pulse generator for driving uniformly as a whole, and a beam splitter disposed between the laser light source and the micromirror device, and the laser beam emitted from the laser light source is perpendicular to the light incident surface of the micromirror device It is characterized by being incident. When the laser beam is incident obliquely on the light incident surface of the micromirror device, the optical path design becomes extremely complicated. On the other hand, when the laser beam is incident vertically through the deflecting beam splitter, the beam emitted from the laser light source and incident on the micromirror device and the beam emitted from the micromirror device are orthogonal to each other. There is an advantage that the optical path design is greatly relaxed.

  Another preferred embodiment of the laser microscope according to the present invention is characterized in that the laser light source is composed of a semiconductor laser that generates measurement light in the ultraviolet or near ultraviolet wavelength region.

  The preferred embodiment of the laser microscope according to the present invention is further characterized by further comprising means for displaying the cross-sectional shape of the sample and the two-dimensional image in a superimposed manner. By displaying the two-dimensional image captured by the observation optical system and the cross-sectional shape superimposed on the monitor via the superimposer, it is possible to clearly grasp which part of the sample the cross-sectional shape was measured.

  In another preferred embodiment of the laser microscope according to the present invention, an incident line-shaped light beam is periodically inserted in a second direction perpendicular to the first direction between the line-shaped light beam generating means and the objective lens. A deflecting oscillating mirror is disposed, and the measurement optical system captures a one-dimensional image of the sample and a two-dimensional confocal image of the sample. In the present invention, since the laser beam is not deflected in the main scanning direction and the sub-scanning direction by using two beam deflecting means, but a line-shaped light beam extending in the main scanning direction is used, vibrations are generated in the optical path. It is possible to scan a sample two-dimensionally only by arranging a mirror. As a result, the laser microscope can not only measure the cross-sectional shape of the sample, but can also capture a two-dimensional confocal image of the sample. Since the confocal image is an image having a higher resolution than the two-dimensional image captured by the observation optical system, the confocal image is suitable for imaging a sample that requires resolution, and can be used for various applications.

In a preferred embodiment of the laser microscope according to the present invention, a drive device that moves the objective lens in the direction of its optical axis is used as means for changing the relative distance between the objective lens and the sample, and the objective is used as the position detection means. A means for detecting the position of the lens in the optical axis direction is used.

Another laser microscope according to the present invention includes a confocal optical system that captures a confocal image of a sample to be observed, an observation optical system that illuminates the sample with observation light and captures a two-dimensional image of the sample, and the confocal lens. In a laser microscope having a signal processing device that performs signal processing on an image signal output from an optical system and an image signal output from an observation optical system and outputs a video signal,
The confocal optical system includes a line-shaped light beam generating unit that converts a laser beam into a non-coherent line-shaped light beam extending in a first direction, and a beam that periodically deflects the incident line-shaped light beam. It is selectively switched between two modes, a deflection mode and a stationary mode that operates as a stationary mirror. In the beam deflection mode, the incident line light beam is periodically shifted in a second direction orthogonal to the first direction. An oscillating mirror that operates as a stationary mirror in a stationary mode, an objective lens that projects the linear light beam toward the sample to be observed, and a means for changing the relative distance between the objective lens and the sample; A position detection means for detecting a relative distance between the objective lens and the sample as position information in the optical axis direction, and a plurality of the detectors arranged in a direction corresponding to the first direction. Has a light receiving element, and a linear § image sensor for outputting an image signal by receiving the linear reflected light emitted from the sample,
The observation optical system includes an illumination light source that generates observation light, a coupling optical system that couples observation light emitted from the illumination light source to the optical path of the objective lens, and reflected light from the sample to the objective lens and the cup. A two-dimensional imaging device that receives light via a ring optical system,
The signal processing circuit includes means for detecting a maximum luminance value of each pixel for a plurality of two-dimensional images captured while changing a relative distance between the objective lens and the sample, and a maximum luminance value of each pixel of the two-dimensional image. And a Z-axis memory for storing a position in the optical axis direction for generating the maximum luminance value of each pixel,
Furthermore, the signal processing circuit detects a maximum luminance value of each pixel for a plurality of one-dimensional images captured while changing the relative distance between the objective lens and the sample, and for each pixel of the one-dimensional image Means for detecting a position in the optical axis direction that generates the maximum luminance value, a memory for storing the detected position, and a means for creating a cross-sectional shape image from the position information stored in the memory;
The oscillating mirror is selectively switched between a beam deflection mode and a stationary mode, and the signal processing circuit is configured such that a two-dimensional confocal image of the sample or a three-dimensional image of the sample when the oscillating mirror is set to the beam deflection mode. When the stationary mode is set, the cross-sectional image of the sample is output.
The laser microscope selectively switches the oscillating mirror so that a two-dimensional image of the sample, a two-dimensional confocal image, a three-dimensional image, a cross-sectional shape image, or a composite in which the cross-sectional shape image is superimposed on the two-dimensional image. An image is selectively output .

  In the present invention, the coupling optical system is constituted by a sharp cut filter that transmits the wavelength light of the laser beam and reflects the observation light. Since the sharp cut filter has excellent characteristics that do not adversely affect the polarization plane characteristics of the laser light, the laser beam emitted from the coupling optical system can be incident on the sample as circularly polarized light. As a result, the confocal image can be captured as a high-quality image.

In the laser microscope according to the present invention , the oscillating mirror is switched between two modes of a beam deflection mode and a stationary mode, and the line-shaped light beam is periodically deflected in the second direction in the beam deflection mode, and in the stationary mode. Acts as a stationary mirror,
Furthermore, the signal processing circuit detects a maximum luminance value of each pixel for a plurality of one-dimensional images captured while changing the relative distance between the objective lens and the sample, and for each pixel of the one-dimensional image It has means for detecting the position in the optical axis direction that generates the maximum luminance value, memory for storing the detected position, and means for creating a cross-sectional shape image from the position information stored in the memory. And
In the present invention, since the surface of the sample is scanned with the line-shaped light beam, the cross-sectional shape of the sample can be imaged only by keeping the vibrating mirror stationary and moving the objective lens in the optical axis direction. Thus, since the cross-sectional shape can be measured in a short time, the cross-sectional shape of the selected part of the sample can be displayed on the monitor after setting the visual field. This cross-sectional shape is limited to the cross-sectional shape in the first direction (main scanning direction), but it can be measured without two-dimensional scanning of the sample surface, which is useful when setting the visual field.

  In the present invention, since the line light beam for converting the laser beam into a non-coherent line light beam is used, the manufacturing cost is further reduced and the time required for measuring the cross-sectional shape is greatly reduced. Is realized. In addition, the measurement optical system and the observation optical system are coupled using a sharp cut filter that transmits laser light and reflects observation light, so that the cost is low and crosstalk does not occur. Can be formed.

  FIG. 1 is a diagram showing an example of a laser microscope according to the present invention. In this example, the measurement optical system 1 and the observation optical system 2 are provided, the cross-sectional shape of the sample is measured by the measurement optical system, and a two-dimensional image of the sample is captured by the observation optical system. The measurement optical system 1 has a laser light source 10. As the laser light source 10, a semiconductor laser that emits measurement light having a wavelength of 408 nm is used. The laser light emitted from the laser light source 10 is converted into an expanded light beam by the expander optical system 11 and converted into a flat beam focused in the second direction by the cylindrical lens 12. The beam passes through the polarization beam splitter 13, passes through the quarter-wave plate 14, and enters the light incident surface of the micromirror device (DMD) 15 perpendicularly.

  In the present invention, each micromirror element of the micromirror device is not individually driven and used as an image display device, but the same drive pulse is supplied to all the micromirror elements from a drive pulse generator (not shown). Then, the incident laser beam is converted into a divergent non-coherent light beam by the high-speed rotation of each mirror surface as a whole. The micromirror device 15 has a plurality of micromirror elements arranged in a two-dimensional matrix on the light incident surface, and each micromirror element has a rectangular aluminum mirror surface of, for example, 14 μm × 14 μm. When the same drive pulse is input to each micromirror element, each mirror surface rotates or reciprocates at high speed as a whole, and deflects the incident laser beam at high speed. That is, each mirror surface is periodically rotated at high speed from one side to the other side with a neutral point between the mirror pillars according to the drive pulse supplied, so that each mirror surface has a center. Each incident beam portion is deflected at high speed. As a result, a divergent line light beam is emitted from the micromirror device 15. The deflection direction by the micromirror device is a first direction orthogonal to the second direction, and the first direction is an extension direction of a line-shaped light beam to be described later.

  On the other hand, each micromirror element of the micromirror device rotates in a random state due to the difference in mass, etc., when viewed microscopically, even if the same drive pulse is input as a whole Or tilt. For this reason, the beam portion incident on each micromirror surface of the incident laser beam is reflected in a random state. As a result, the line-shaped light beam emitted from the micromirror device is converted into a divergent, non-coherent light beam because the phase relationship becomes random when viewed as a whole beam, the coherency is no longer maintained. The As a result, it is possible to capture a clear image in which no glare or the like occurs. It has been proved by experiments that the laser beam is converted into a non-coherent light beam by the micromirror device.

  The non-coherent line light beam emitted from the micromirror device 15 passes through the quarter-wave plate 14 and is reflected by the polarization plane of the polarization beam splitter 13. The light beam emitted from the polarization beam splitter 13 enters the converging spherical lens 16 and is converted into a parallel light beam expanded in the first direction. The line-shaped parallel light beam is converged in the second direction by the second cylindrical lens 17, and enters the second polarization beam splitter 19 through the relay lens 18. The light beam emitted from the second polarization beam splitter passes through the quarter wavelength plate 20 and enters the coupling optical system 21.

  The coupling optical system 21 is an optical system that optically couples the measurement optical system 1 and the observation optical system 2, and includes, for example, a sharp cut filter in which a dielectric multilayer film is formed on an optically transparent substrate. To do. The sharp cut filter functions as a beam splitter that transmits measurement light having a wavelength of 408 nm and reflects visible light having a wavelength of 450 nm or more. The reflection characteristics of the sharp cut filter are shown in FIG. Since the sharp cut filter has good polarization plane characteristics, it can be incident on the objective lens without harming the polarization plane characteristics of the light beam incident as circularly polarized light.

  The light beam that has passed through the coupling optical system 21 enters the objective lens 23 through the imaging lens 22. A servo motor 24 is connected to the objective lens 23, and can be moved along the optical axis direction by this servo motor. Further, an encoder 25 for detecting the position of the objective lens 23 in the optical axis direction is provided, and the encoder 25 detects the position of the objective lens in the optical axis direction. It is also possible to change the relative distance between the objective lens and the sample by fixing the objective lens and moving the stage supporting the sample in the optical axis direction of the objective lens.

  The measurement beam is focused by the objective lens 23 and is incident on the sample 27 to be observed placed on the stage 26 as a convergent line-shaped light beam. During scanning of the sample surface, the Z-axis scan is performed by moving the objective lens 23 along the optical axis direction. In this case, since the converging line of the line-shaped light beam moves in the optical axis direction, when the surface of the sample 23 is uneven, each part of the sample surface is sequentially scanned by the converging line. During scanning, the position of the objective lens 23 in the optical axis direction is detected by the encoder 25. As described later, the position information in the Z-axis direction on the surface of the sample is detected using the position information in the Z-axis direction detected by the encoder 25.

  Line-shaped reflected light is generated from the sample 27, and the line-shaped reflected light is collected by the objective lens 23, passes through the imaging lens 22, the coupling optical system 21, and the ¼ wavelength plate 20, and is then a polarizing beam splitter. 19 enters. Since the reflected light from the sample passes through the quarter-wave plate 20 twice, it passes through the polarizing beam splitter 19 and enters the linear image sensor 29 through a filter 28 that cuts light having a wavelength of 420 nm or more. . The filter 28 is not necessarily a necessary component, and is disposed as necessary.

  The linear image sensor 29 has a plurality of light receiving elements arranged in a direction corresponding to the first direction which is the extending direction of the linear light beam, and the linear reflected light from the sample is the linear image sensor 29. The light receiving elements receive the light. The charges accumulated in each light receiving element are sequentially read out at a predetermined frequency under the control of a controller (not shown), amplified by the amplifier 30, and input to the signal processing device 31 as a one-dimensional image signal. In this example, a sharp cut filter that acts as a beam splitter that transmits measurement light and reflects observation light is used as the coupling optical system 21, so that almost no observation light is incident on the linear image sensor 29. As a result, an image signal with significantly reduced noise is output.

  The signal processing circuit 31 performs signal processing on the image signals sequentially read from the linear image sensor 29 to generate a video output. The position information of the objective lens detected by the encoder 25 is also supplied to the signal processing circuit 31. The drive control of the servo motor 24 is also performed under the control of the controller.

  Next, the observation optical system 2 will be described. Observation light generated from a white light source (not shown) such as a halogen lamp is introduced into the optical path of the observation optical system by the optical fiber 32. The observation light enters the coupling optical system 21 through the beam splitter 33, the imaging lens 34, and the filter 35 that cuts light having a wavelength of 430 nm or less. Note that the filter 35 is not always necessary, and is disposed as necessary. Since the coupling optical system 21 functions as a beam splitter that transmits measurement light having a wavelength of 408 nm and reflects visible light having a wavelength of 450 nm or more, the observation light is reflected by the coupling optical system 21 and propagates through the optical path of the measurement optical system. Then, the surface of the sample 27 is illuminated through the imaging lens 22 and the objective lens 23. Since the measurement optical system 1 and the observation optical system 2 use the objective lens in common, the observation light from the observation optical system illuminates the visual field including the visual field of the measurement optical system 1 of the sample 27. The observation light reflected from the sample surface is collected by the objective lens 23 and enters the beam splitter 33 through the imaging lens 22, the coupling optical system 21, the filter 35, and the imaging lens 34. Then, the light is reflected by the beam splitter 33 and imaged on the two-dimensional CCD 36. A two-dimensional image signal output from the two-dimensional CCD 36 is supplied to the signal processing circuit 31.

  FIG. 3 is a diagram showing an example of a signal processing circuit. The one-dimensional image signal output from the linear image sensor 29 is amplified by the amplifier 30 and converted into a digital one-dimensional image signal by the A / D converter 40. The one-dimensional image signal is supplied to the comparator 41. The one-dimensional image signal is also supplied to the selector 42 and is stored in the memory 43 via the selector. The image signal stored in the memory 43 is supplied to the second input of the comparator 41 and the selector 42. The comparator 41 compares the image signal sequentially input from the linear image sensor 29 and the image signal input from the memory 43 for each pixel. If the luminance value of the image signal input from the linear image sensor is large, the comparator 41 A control signal is generated and supplied to the selector 42 as a control signal. The selector 42 supplies a new luminance value to the memory 43. Thus, when the Z-axis scan is completed, a one-dimensional image signal that maximizes the luminance value of each pixel is accumulated in the memory 43.

  The objective lens position information output from the encoder 25 is counted by the counter 44 and supplied to the Z-axis memory 45. A write control signal output from the comparator 41 is also input to the Z-axis memory 45, and an output signal from the encoder is written to the Z-axis memory 45 for each pixel using this write control signal as a trigger. Therefore, when the scanning of the objective lens in the Z-axis direction is completed, the position information of the objective lens 23 that generates the maximum luminance value is written in the Z-axis memory 45. Since the position information in the Z-axis direction where the luminance value is maximized is the position when the focal point of the line-shaped light beam incident on the sample is positioned on the sample surface, the Z-axis memory 45 stores the position information from the reference position. Information on the height of the sample, that is, information indicating the cross-sectional shape or cross-sectional profile of the sample is stored.

  The position information stored in the Z-axis memory 45 is supplied to the calculation unit 46, the cross-sectional shape of the sample is calculated by the calculation process, and the cross-sectional shape information is stored in the cross-sectional shape memory 47. The cross-sectional shape information is supplied to the mode changeover switch 49 for switching the image displayed on the monitor 48 and also to the super impose 50.

  The two-dimensional image signal output from the two-dimensional CCD 36 is converted into a digital signal by the A / D converter 51 and stored in the image memory 52. The two-dimensional image signal is supplied to the mode changeover switch 49 and also to the superimposer 50. The superimposer 50 synthesizes the two-dimensional image of the sample and the cross-sectional shape, and outputs a synthesized image signal to the mode switch 49. As a result, the mode changeover switch 49 outputs to the monitor 48 one of the two-dimensional image of the sample, the cross-sectional shape, and the composite image in which the cross-sectional shape is superimposed on the two-dimensional image in response to a switching signal input by the user. To do.

  Next, the operation of the laser microscope will be described. The user sets a sample to be observed, captures a two-dimensional image of the sample captured by the two-dimensional CCD, and outputs it on the monitor. Next, while looking at the monitor, a field of view for capturing the cross-sectional shape is set. Next, the imaging mode is switched and the cross-sectional shape is measured. The obtained cross-sectional shape is superimposed on the two-dimensional image and output to the monitor. Alternatively, only the cross-sectional shape can be displayed on the monitor.

  Next, a laser microscope that captures a two-dimensional image, a two-dimensional confocal image, a three-dimensional image, and a cross-sectional shape of a sample will be described. FIG. 4 is a diagram showing a second embodiment of the laser microscope according to the present invention. In the laser microscope shown in FIG. 4, the same members as those shown in FIG. The optical system for converting the laser beam into a non-coherent line-shaped light beam is the same as the laser microscope shown in FIG. 1, and in this example, a total reflection mirror 60 is provided in the optical path between the cylindrical lens 12 and the polarization beam splitter 13. Place and fold the optical path. In this example, in the optical path between the second beam splitter 19 and the coupling optical system 21, the quarter-wave plate 20, the imaging lens 61, the vibration mirror 62, the relay lens 63, and the total reflection mirror 64 are sequentially provided. Place. The oscillating mirror 62 periodically deflects the incident line-shaped light beam at a predetermined frequency in a direction orthogonal to the extending direction. Therefore, the sample 27 is periodically two-dimensionally scanned by the line-shaped light beam. Note that a relay lens 65 is disposed downstream of the observation optical system 21.

The line-shaped reflected light from the sample 27 propagates in the reverse direction along the optical path and enters the vibrating mirror 62. The incident reflected beam is descanned by the vibrating mirror and enters the polarizing beam splitter 19 through the imaging lens 61 and the quarter-wave plate 20.
Further, the light passes through the polarizing beam splitter 19, enters the linear image sensor 29 through the filter 28. Since the incident line-shaped reflected beam is descanned by the vibrating mirror 62, the line-shaped reflected light from the sample is stationary on the linear image sensor. The charges accumulated in each light receiving element of the linear image sensor are sequentially read out at a predetermined frequency under the control of the controller 66, amplified by the amplifier 30, and supplied to the signal processing circuit 67. The drive control of the vibrating mirror 62 and the servo motor 24 is also performed under the control of the controller 66. In this example as well, a sharp cut filter that transmits laser light and reflects observation light is used as the coupling optical system, so almost no observation light is incident on the linear image sensor and noise is greatly reduced. A signal is output.

  The observation optical system has the same configuration as the observation optical system shown in FIG.

  FIG. 5 is a diagram showing an example of a signal processing circuit of the laser microscope of the second embodiment. The same members as those used in the signal processing circuit shown in FIG. The output signal from the linear image sensor 29 is amplified by the amplifier 30, converted into a digital signal by the A / D converter 40, input to the comparator 70, and also supplied to the selector 71, and the first signal passes through the selector 71. Are stored in the image memory 72. Each pixel value of the two-dimensional image of the sample is stored in the first image memory 72, and each pixel value is supplied to the comparator 70. The comparator 70 sequentially compares the pixel value stored in the first image memory 72 and the pixel value output from the linear image sensor for each pixel of the two-dimensional image, and calculates the newly input pixel value. If it is greater, a write control signal is generated and supplied to the selector 72. The selector 71 is supplied with the pixel value stored in the first image memory 72 together with the output signal from the linear image sensor, and when the output from the linear image sensor is large, the writing output from the comparator is performed. The output value from the linear image sensor is selected by the control signal and written to the first image memory 72. In this way, the two-dimensional confocal image information of the sample is stored in the first image memory 72. The two-dimensional confocal image stored in the first image memory 72 is supplied to the mode changeover switch 73.

  An output signal from the encoder 25 is counted by the counter 44 and supplied to the Z-axis memory 45. An output signal from the comparator 70 is input to the Z-axis memory 45 as a write control signal. Then, position information in the Z-axis direction that generates the maximum luminance value is written in the Z-axis memory 45 for each pixel. When calculating the cross-sectional shape in the direction specified by the user, the position information in the specified direction is supplied from the position information stored in the Z-axis memory to the cross-sectional shape calculation unit 46, and the cross-sectional shape image in the specified direction Is calculated, and the calculated cross-sectional shape image is stored in the cross-sectional shape memory 47.

  The two-dimensional confocal image stored in the first image memory 72 and the position information stored in the Z-axis memory 45 are supplied to the three-dimensional image creation unit 74 to create a three-dimensional image of the sample. That is, since the position information stored in the Z-axis memory is depth information or height information of the sample surface, a three-dimensional image of the sample surface is created using this height information and a two-dimensional confocal image. Can do. The created three-dimensional image is output to the mode switch 73.

  The image signal from the two-dimensional CCD 36 is A / D converted by the A / D modulator 51 and stored in the second image memory 52. The two-dimensional image information stored in the second image memory 52 is supplied to the switch 75 and also to the mode changeover switch 73. The switch 75 is also supplied with two-dimensional confocal image information stored in the first image memory 72. This switch 75 selects whether to use a two-dimensional confocal image or a normal two-dimensional image as a two-dimensional image superimposed on the cross-sectional shape of the sample. When it is desired to superimpose the cross-sectional shape images, the image in the second image memory is selected, and when the two-dimensional confocal image is desired, the image stored in the first image memory is selected. The selected two-dimensional image is supplied to the superimposer 76. The superimposer also receives a cross-sectional shape image stored in the cross-sectional shape memory 47, outputs an image in which the cross-sectional shape image is superimposed on the two-dimensional image, and supplies the image to the mode switch 73.

Next, the operation of the laser microscope will be described. The laser microscope of this example can observe the sample in the following six modes by switching the mode changeover switch.
Mode 1: Two-dimensional image display mode Mode 2: Two-dimensional confocal image display mode Mode 3: Three-dimensional image display mode Mode 4: Cross-sectional shape display mode Mode 5: Superimposed image display mode 1 (2D image + cross-sectional shape)
Mode 6: Superimposed image display mode 2 (2D confocal image + sectional shape)
The above six modes are displayed by switching the mode switch 73.

  When observing the sample, the user sets the sample to be observed, sets the changeover switch to mode 1, and captures a normal two-dimensional image of the sample. By setting the display mode selector switch to mode 1, only the observation optical system is driven, and a two-dimensional image of the sample is taken and stored in the second image memory. At the same time, the mode switch 73 is switched to supply the image information in the second image memory 52 to the monitor, and a normal two-dimensional image is displayed on the monitor 48.

  If the user wishes to observe the confocal image after setting the field of view, the user sets the changeover switch to mode 2. When the mode 2 is set, the confocal optical system is driven, a confocal image of the designated visual field is captured, and the two-dimensional confocal image is stored in the first image memory 72. Further, the mode changeover switch 73 is switched and a two-dimensional confocal image is displayed on the monitor. In this confocal image capturing mode, an omnifocal image in which all parts are in focus is captured even with a sample having uneven surfaces.

  Further, when the user wishes to observe the cross-sectional shape of a specific part by observing the confocal image, the user sets the changeover switch to mode 6. When the mode 6 is set, the cross-sectional shape calculation unit 46 is driven, calculates the cross-sectional shape from pixel position information in the designated direction, and supplies the obtained cross-sectional shape image to the cross-sectional shape memory 47. Further, the switch 75 is set to supply a two-dimensional confocal image to the superimposer 75, and the superimposer is supplied with the two-dimensional confocal image and the cross-sectional shape image stored in the cross-sectional shape memory. An image in which the cross-sectional shape image in the designated direction is superimposed on the confocal image is supplied to the mode switch and displayed on the monitor. Of course, by setting to mode 5, it is also possible to display an image in which a cross-sectional image is superimposed on a normal two-dimensional image stored in the second image memory.

Next, a modification of the laser microscope shown in FIGS . 4 and 5 will be described. As the oscillating mirror 62, an oscillating mirror that is switched between a beam deflection mode that periodically deflects a linear light beam in the second direction and a stationary mode that is used as a stationary mirror is used. A two-dimensional confocal image is captured in the beam deflection mode, and a cross-sectional shape in the first direction (main scanning direction) is captured in the still mode. In the present invention, the surface of the sample is two-dimensionally scanned with a line-shaped light beam, so that the cross-sectional shape of the sample can be imaged simply by moving the objective lens in the optical axis direction using a vibrating mirror as a stationary mirror. Is achieved. In this case, since the cross-sectional shape is imaged without scanning the sample surface two-dimensionally, the cross-sectional shape image can be easily displayed on the monitor in a short time. In this case, it is possible to display on the monitor simply by adding a circuit including the comparator 41, the selector 42, the memory 43, and the Z-axis memory 45 shown in FIG. 3, and supply the cross-sectional shape image to the superimposer. By doing so, the cross-sectional shape can be superimposed on the two-dimensional image.

  The present invention is not limited to the above-described embodiments, and various modifications and changes can be made. In the embodiment described above, the objective lens is driven to change the relative distance between the objective lens and the sample. However, a three-dimensional drive type stage is used as the sample stage, and the stage is driven in the Z-axis direction. It is also possible to change the relative distance between the lens and the sample.

1 is a diagram showing an optical system of a first embodiment of a laser microscope according to the present invention. It is a diagram which shows the light transmission reflection characteristic of a sharp cut filter. It is a line which shows an example of the signal processing circuit of a 1st Example. It is a diagram which shows the optical system of 2nd Example of the laser microscope by this invention. It is a diagram which shows the signal processing circuit of a 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measurement optical system 2 Observation optical system 10 Laser light source 11 Expander optical system 12, 17 Cylindrical lens 13, 19 Polarizing beam splitter 14, 20 1/4 wavelength plate 15 Micromirror device 16 Lens 18 Relay lens 21 Coupling optical system 22 , 34 Imaging lens 23 Objective lens 24 Servo motor
25 Encoder 26 Stage 27 Sample 28, 35 Filter 29 Linear image sensor 30 Amplifier 31 Signal processing circuit 32 Optical fiber 33 Beam splitter 36 Two-dimensional CCD
40, 51 A / D converter 41 Comparator 42 Selector 43 Memory 44 Counter 45 Z-axis memory 46 Cross-sectional shape calculation unit 47 Cross-sectional shape memory 48 Monitor 49 Mode changeover switch 50 Superimposer 52 Image memory

Claims (6)

A confocal optical system that captures a confocal image of a sample to be observed, an observation optical system that illuminates the sample with observation light and captures a two-dimensional image of the sample, an image signal output from the confocal optical system, and In a laser microscope having a signal processing device that performs signal processing on an image signal output from an observation optical system and outputs a video signal,
The confocal optical system includes a line-shaped light beam generating unit that converts a laser beam into a non-coherent line-shaped light beam extending in a first direction, and the line-shaped light beam orthogonal to the first direction. Beam deflecting means for periodically deflecting in the second direction, an objective lens for projecting the line-shaped light beam toward the specimen to be observed, means for changing the relative distance between the objective lens and the specimen, A position detection unit that detects a relative distance between the objective lens and the sample as position information in the optical axis direction and a plurality of light receiving elements arranged in a direction corresponding to the first direction, and emits from the sample. A linear image sensor that receives line-like reflected light and outputs an image signal ;
The observation optical system includes an illumination light source that generates observation light, a coupling optical system that couples observation light emitted from the illumination light source to the optical path of the objective lens, and reflected light from the sample to the objective lens and the cup. A two-dimensional imaging device that receives light via a ring optical system,
The signal processing circuit includes means for detecting a maximum luminance value of each pixel for a plurality of two-dimensional images captured while changing a relative distance between the objective lens and the sample, and a maximum luminance value of each pixel of the two-dimensional image. A first image memory for storing the image, a Z-axis memory for storing a position in the optical axis direction at which the maximum luminance value of each pixel is generated, and a second image information for storing the two-dimensional image information output from the two-dimensional imaging device. Two image memories,
The line-shaped light beam is composed of light in the ultraviolet or near ultraviolet wavelength region, and the observation light is composed of white light in the visible region,
The coupling optical system is configured by a sharp cut filter that transmits light constituting the line-shaped light beam and reflects the observation light,
The laser microscope outputs a two-dimensional image of a sample, a two-dimensional confocal image, a three-dimensional image, a cross-sectional shape image, or a composite image in which the cross-sectional shape image is superimposed on the two-dimensional image. . 2. The laser microscope according to claim 1, wherein the means for converting the laser beam into a non-coherent line-shaped light beam includes a laser light source and a plurality of micromirror elements arranged in a two-dimensional matrix on the light incident surface. A laser microscope comprising: a mirror device; and a drive pulse generator for driving the micromirror element uniformly as a whole . A confocal optical system that captures a confocal image of a sample to be observed, an observation optical system that illuminates the sample with observation light and captures a two-dimensional image of the sample, an image signal output from the confocal optical system, and In a laser microscope having a signal processing device that performs signal processing on an image signal output from an observation optical system and outputs a video signal,
The confocal optical system includes a line-shaped light beam generating unit that converts a laser beam into a non-coherent line-shaped light beam extending in a first direction, and a beam that periodically deflects the incident line-shaped light beam. It is selectively switched between two modes, a deflection mode and a stationary mode that operates as a stationary mirror. In the beam deflection mode, the incident line light beam is periodically shifted in a second direction orthogonal to the first direction. An oscillating mirror that operates as a stationary mirror in a stationary mode, an objective lens that projects the linear light beam toward the sample to be observed, and a means for changing the relative distance between the objective lens and the sample; A position detection means for detecting a relative distance between the objective lens and the sample as position information in the optical axis direction, and a plurality of the detectors arranged in a direction corresponding to the first direction. Has a light receiving element, and a linear § image sensor for outputting an image signal by receiving the linear reflected light emitted from the sample,
The observation optical system includes an illumination light source that generates observation light, a coupling optical system that couples observation light emitted from the illumination light source to the optical path of the objective lens, and reflected light from the sample to the objective lens and the cup. A two-dimensional imaging device that receives light via a ring optical system,
The signal processing circuit includes means for detecting a maximum luminance value of each pixel for a plurality of two-dimensional images captured while changing a relative distance between the objective lens and the sample, and a maximum luminance value of each pixel of the two-dimensional image. And a Z-axis memory for storing a position in the optical axis direction for generating the maximum luminance value of each pixel,
Furthermore, the signal processing circuit detects a maximum luminance value of each pixel for a plurality of one-dimensional images captured while changing the relative distance between the objective lens and the sample, and for each pixel of the one-dimensional image Means for detecting a position in the optical axis direction that generates the maximum luminance value, a memory for storing the detected position, and a means for creating a cross-sectional shape image from the position information stored in the memory;
The signal processing circuit outputs a two-dimensional confocal image of the sample or a three-dimensional image of the sample when the vibrating mirror is set in the beam deflection mode, and outputs a cross-sectional shape image of the sample when set in the stationary mode,
The laser microscope selectively switches the oscillating mirror so that a two-dimensional image of the sample, a two-dimensional confocal image, a three-dimensional image, a cross-sectional shape image, or a composite in which the cross-sectional shape image is superimposed on the two-dimensional image. A laser microscope characterized by selectively outputting an image . 4. The laser microscope according to claim 3, wherein the signal processing circuit includes means for superimposing a cross-sectional shape image of the sample imaged by the confocal optical system and a two-dimensional image of the sample imaged by the observation optical system. ,
The laser microscope selectively switches the oscillating mirror so that a two-dimensional image captured by the observation optical system in addition to a two-dimensional image, a two-dimensional confocal image, a three-dimensional image, and a cross-sectional image of the sample. A laser microscope characterized by outputting a composite image in which a cross-sectional image captured in a state where the vibration mirror is set to a stationary mode is superimposed . 5. The laser microscope according to claim 3, wherein the coupling optical system includes a sharp cut filter that transmits the wavelength light constituting the linear light beam and reflects the observation light. Laser microscope. 6. The laser microscope according to claim 5, wherein the line-shaped light beam generating means generates a line-shaped light beam composed of wavelength light in a wavelength region of ultraviolet or near ultraviolet, and the illumination light source for generating the observation light is Generates visible white light,
The laser microscope characterized in that the coupling optical system includes a sharp cut filter that transmits light in the ultraviolet or near-ultraviolet wavelength region and reflects light in the visible region .