JP4367261B2 - Microscope observation method, microscope apparatus, and image processing apparatus - Google Patents

Description

  The present invention relates to a microscope observation method for observing a test object such as an industrial part such as a semiconductor or a living body such as a biological cell with an optical microscope, a microscope apparatus applied to the microscope observation method, and an image applied to the microscope apparatus. The present invention relates to a processing apparatus.

In order to improve the resolving power of an optical microscope (hereinafter simply referred to as “microscope”), it is generally necessary to increase the numerical aperture of the objective lens or shorten the wavelength of the light source (see Non-Patent Document 1, etc.). .
Kei Komatsu, “Basics and Applications of Optical Microscope (1)”, Applied Physics, 1991, Vol. 60, No. 8, 1991, p816-p817

However, the type of light source used is limited depending on the type of the test object and the observation purpose, and the optical system material is often limited by the light source used. Therefore, the resolution of each microscope in each field has its limits. .
SUMMARY OF THE INVENTION An object of the present invention is to provide a microscope observation method capable of obtaining a high resolving power exceeding the capability of an imaging optical system of a microscope apparatus.

Another object of the present invention is to provide a microscope apparatus suitable for carrying out the microscope observation method.
Another object of the present invention is to provide an image processing apparatus capable of obtaining a high resolving power exceeding the capability of the imaging optical system of the microscope apparatus.

  The microscope observation method according to claim 1, further comprising: an imaging optical system that forms an image of a light beam emitted from an illuminated test object, and a complex amplitude distribution of a light wave generated on an imaging surface of the imaging optical system A microscope observation method using a microscope apparatus capable of measuring the above, wherein the illumination angle of the test object is changed, and each light beam emitted from the test object when the illumination angle is at each value Based on the measurement procedure for measuring the complex amplitude distribution of each light wave generated individually on the surface and the data of the complex amplitude distribution of each light wave, the imaging optical system is changed to a virtual imaging optical system having a larger numerical aperture. Based on the calculation procedure for calculating the complex amplitude distribution of the virtual light wave that occurs on the imaging plane when replaced, and the object to be formed on the imaging plane by the virtual imaging optical system based on the complex amplitude distribution of the virtual light wave. Image creation procedure to create image data of virtual image of inspection Characterized in that it contains.

  The microscope observation method according to claim 2 is the microscope observation method according to claim 1, wherein the calculation procedure includes Fourier transforming a complex amplitude distribution of each light wave with respect to a space, and each light beam is converted into the imaging optical system. The procedure for calculating the complex amplitude distribution of each light wave to be individually generated on the pupil of the image, and the composite amplitude distribution of each light wave are synthesized by laterally shifting, and the virtual light wave generated on the pupil of the virtual imaging optical system is synthesized. A procedure for calculating a complex amplitude distribution; and a procedure for performing an inverse Fourier transform on the complex amplitude distribution of the virtual light wave with respect to space and calculating a complex amplitude distribution of the virtual light wave generated on the imaging plane of the virtual imaging optical system. It is characterized by that.

The microscope observation method according to claim 3 is the microscope observation method according to claim 2, wherein, in the calculation procedure, in the synthesis, a phase offset caused by a variation between the light waves is obtained from a complex amplitude distribution of the light waves. And / or correcting an amplitude offset.
The microscope observation method according to claim 4 is the microscope observation method according to any one of claims 1 to 3, wherein in the calculation procedure, the imaging is performed as data of a complex amplitude distribution of each light wave. A single optical system uses data in which a phase component that is superposed in common with each of the light waves is corrected.

  The microscope observation method according to claim 5 is the microscope observation method according to any one of claims 1 to 4, wherein the microscope apparatus includes an illumination unit that illuminates the test object with pulsed light; The imaging optical system that forms an image of a light beam emitted from the test object, a detection unit that detects an electric field intensity distribution of a light wave generated on an imaging surface of the imaging optical system, and an emission timing of the pulsed light; Control means for controlling the detection timing to detect a temporal change of the intensity distribution within one light emission period and calculating a complex amplitude distribution of a light wave generated on the imaging plane based on the data of the temporal change; It is characterized by having.

The microscope observation method according to a sixth aspect is the microscope observation method according to the fifth aspect, wherein the pulsed light is terahertz pulsed light.
The microscope apparatus according to claim 7, an illuminating unit that illuminates a test object with pulsed light, the imaging optical system that forms an image of a light beam emitted from the test object, and an imaging of the imaging optical system Detecting means for detecting the electric field intensity distribution of the light wave generated on the surface, and detecting the time change of the intensity distribution within one light emission period by controlling the light emission timing and the detection timing of the pulsed light, and the time Control means for calculating a complex amplitude distribution of a light wave generated on the imaging plane based on change data; and change means for changing the illumination angle of the object to be examined. It is characterized in that a complex amplitude distribution of each light wave caused by each light beam emitted from the test object to be individually generated on the imaging plane when the value is in a value is measured.

The microscope apparatus according to an eighth aspect is the microscope apparatus according to the seventh aspect, wherein the pulsed light is terahertz pulsed light.
The microscope apparatus according to claim 9 is the microscope apparatus according to claim 7 or claim 8, wherein the control means is configured to make the imaging optical system more than that based on data of a complex amplitude distribution of each light wave. Based on the calculation procedure for calculating the complex amplitude distribution of the virtual light wave generated on the imaging plane when the virtual imaging optical system is replaced with a virtual imaging optical system having a large numerical aperture, and the virtual imaging optical system based on the complex amplitude distribution of the virtual light wave And an image creation procedure for creating image data of a virtual image of the test object formed on the imaging plane.

  In the microscope apparatus according to claim 10, in the microscope apparatus according to claim 9, in the calculation procedure, the control unit Fourier-transforms a complex amplitude distribution of each light wave with respect to a space, and the light beams are combined with each other. A virtual light wave generated on the pupil of the virtual imaging optical system is calculated by calculating a complex amplitude distribution of each light wave individually generated on the pupil of the image optical system, and by synthesizing the complex amplitude distribution of each light wave laterally shifted. The complex amplitude distribution of the virtual light wave is calculated, the complex amplitude distribution of the virtual light wave is inverse Fourier transformed with respect to space, and the complex amplitude distribution of the virtual light wave generated on the imaging plane of the virtual imaging optical system is calculated. .

The microscope apparatus according to claim 11 is the microscope apparatus according to claim 10, wherein the control means is caused by a variation between light waves based on a complex amplitude distribution of the light waves in the calculation procedure. The phase offset and / or the amplitude offset is corrected.
The microscope apparatus according to claim 12 is the microscope apparatus according to any one of claims 9 to 11, wherein the control unit is configured to calculate complex amplitude distribution data of each light wave in the calculation procedure. A single image forming optical system uses data in which a phase component that is superposed in common with each of the light waves is corrected.

  An image processing apparatus according to a thirteenth aspect is an image processing apparatus applied to the microscope apparatus according to the seventh or eighth aspect, wherein the imaging optics is based on data of a complex amplitude distribution of each light wave. Based on the complex amplitude distribution of the virtual light wave, the calculation means for calculating the complex amplitude distribution of the virtual light wave generated on the imaging plane when the system is replaced with a virtual imaging optical system having a larger numerical aperture than the system, The virtual imaging optical system includes image creating means for creating image data of a virtual image of the test object formed on the imaging surface.

  The image processing device according to claim 14 is the image processing device according to claim 13, wherein the calculation unit Fourier-transforms a complex amplitude distribution of each light wave with respect to space, and the light beams are converted into the imaging optical system. The complex amplitude distribution of each light wave to be individually generated on the pupil of the virtual wave, the complex amplitude distribution of each light wave is synthesized by shifting laterally, and the complex amplitude of the virtual light wave to be generated on the pupil of the virtual imaging optical system The distribution is calculated, the complex amplitude distribution of the virtual light wave is subjected to inverse Fourier transform with respect to space, and the complex amplitude distribution of the virtual light wave generated on the imaging plane of the virtual imaging optical system is calculated.

The image processing device according to claim 15 is the image processing device according to claim 14, wherein, in the synthesis, the calculation unit calculates, from the complex amplitude distribution of the light waves, a phase offset caused by variation between the light waves. And / or correcting an amplitude offset.
The image processing device according to claim 16 is the image processing device according to any one of claims 13 to 15, wherein the calculation means uses the imaging as data of a complex amplitude distribution of each light wave. A single optical system uses data in which a phase component that is superposed in common with each of the light waves is corrected.

According to the present invention, a microscope observation method capable of obtaining a high resolving power exceeding the capability of the imaging optical system of the microscope apparatus is realized.
Further, according to the present invention, a microscope apparatus suitable for carrying out the microscope observation method is realized.
In addition, according to the present invention, an image processing apparatus capable of obtaining a high resolving power exceeding the capability of the imaging optical system of the microscope apparatus is realized.

Embodiments of the present invention will be described below.
The present embodiment is an embodiment of a super-resolution microscope system and a microscope observation method using the same.
First, the configuration of this system will be described.
As shown in FIG. 1, the system includes a terahertz spectroscopic imaging apparatus (reference numerals 11 to 21), a computer 30, a display 40, and the like. The terahertz spectroscopic imaging apparatus corresponds to the microscope apparatus according to the claims, and the computer corresponds to the image processing apparatus according to the claims.

  The terahertz spectroscopic imaging apparatus includes a femtosecond pulse laser 11, a beam expander 12, a semiconductor substrate 13 serving as a terahertz light source, an imaging optical system 14 made of special plastic, an electro-optic crystal 15, a polarizing plate 16, a CCD camera 17, A delay device 18, a high voltage power source 19, a control circuit 20, a stage 21, and the like are provided. This stage corresponds to the changing means in the claims. Reference numerals HM and M indicate half mirrors and mirrors, and reference numeral 1 indicates a test object. Details of the terahertz spectroscopic imaging apparatus are disclosed in, for example, Japanese Patent Laid-Open Nos. 2003-295104 and 2002-5828. In FIG. 1, the delay device 18 is represented as if constituted by an optical system, but another configuration of the delay device 18 having the same function may be used.

The computer 30 is preinstalled with a program necessary for realizing the present observation method (described later). Note that part or all of the processing of the control circuit 20 described below may be executed by the computer 30, and part or all of the processing of the computer 30 described below is executed by the control circuit 20. May be.
Next, the basic operation of this system will be described.

The femtosecond pulse laser 11 emits femtosecond pulse laser light at a timing instructed by the control circuit 20. This laser light becomes a light beam with a large diameter by the beam expander 12 and is branched into two by the half mirror HM.
One of the two branched laser beams passes through the mirror M and enters the semiconductor substrate 13 on which the electrodes are formed. A voltage is constantly applied to the electrodes by the power source 19, and discharge occurs between the electrodes at the moment when the laser beam is incident. This becomes a dipole and emits terahertz pulse light (terahertz pulse light). The terahertz pulse light illuminates the test object 1.

Light emitted from the test object 1 illuminated by the terahertz pulse light (which is terahertz pulse light) is imaged by the imaging optical system 14. An electro-optic crystal 15 is disposed on the image plane I. In the electro-optic crystal 15, the birefringence is modulated according to the electric field intensity distribution of the light wave generated on the imaging plane I.
On the other hand, the other bifurcated laser beam enters the electro-optic crystal 15 through the delay device 18, the mirror M, and the half mirror HM. The delay device 18 delays the timing at which the laser light enters the electro-optic crystal 15 by a time (delay time) instructed by the control circuit 20.

The polarization state of the laser light incident on the electro-optic crystal 15 is modulated by the birefringence distribution in the electro-optic crystal 15. The distribution of the polarization state of the laser light can be recognized as an image by the CCD camera 17 through the polarizing plate 16.
The CCD camera 17 takes an image at a timing instructed by the control circuit 20 and acquires image data. The image data indicates the electric field intensity distribution of the light wave of the terahertz light incident on the imaging plane I at the moment when the laser light is incident on the electro-optic crystal 15.

The control circuit 20 controls the emission timing of the femtosecond pulse laser 11, the delay time of the delay device 18, and the imaging timing of the CCD camera 17. The control circuit 20 performs light emission and imaging while shifting the delay time by a minute amount, and acquires image data (image data group) of the electric field intensity distribution of the light wave generated on the imaging plane I at each moment in the pulse emission period.
The image data group is taken into the computer 30 via the control circuit 20. The computer 30 performs a Fourier transform (temporal Fourier transform) on the time change of the electric field intensity distribution indicated by the image data group to obtain a complex amplitude distribution of each wavelength component of the light wave generated on the imaging plane I.

Next, the characteristic operation of the terahertz spectroscopic imaging apparatus when the present observation method is performed will be described.
The feature is in the operation of the stage 21. The stage 21 supports the semiconductor substrate 13 and changes the posture of the semiconductor substrate 13 in accordance with an instruction from the control circuit 20 (see FIGS. 3A, 4A, 4B, which will be described later). ).

Here, it is assumed that the posture of the semiconductor substrate 13 adopts an XYZ orthogonal coordinate system with the optical axis as the Z axis and can be changed to the following postures (0) to (8).
(0) Posture in which the substrate normal coincides with the Z-axis (inclination angle θ = θ _{0 of the} semiconductor substrate 13),
(1) A posture in which the substrate normal is inclined by a predetermined amount in the −X direction from the Z axis (inclination angle θ = θ _{1 of the} semiconductor substrate 13),
(2) A posture in which the substrate normal is inclined by a predetermined amount in the + X direction from the Z axis (inclination angle θ = θ _{2 of the} semiconductor substrate 13),
(3) A posture in which the substrate normal is inclined by a predetermined amount in the −Y direction from the Z axis (inclination angle θ = θ _{3 of the} semiconductor substrate 13),
(4) A posture in which the substrate normal is inclined by a predetermined amount in the + Y direction from the Z-axis (inclination angle θ = θ _{4 of the} semiconductor substrate 13),
(5) A posture in which the substrate normal is inclined by a predetermined amount in the −X and −Y directions from the Z axis (inclination angle θ = θ _{5 of the} semiconductor substrate 13),
(6) A posture in which the substrate normal is inclined by a predetermined amount in the + X and −Y directions from the Z axis (inclination angle θ = θ _{6 of the} semiconductor substrate 13),
(7) A posture in which the substrate normal is inclined by a predetermined amount in the + X and + Y directions from the Z axis (inclination angle θ = θ _{7 of the} semiconductor substrate 13),
(8) The posture in which the substrate normal is inclined by a predetermined amount in the −X and + Y directions from the Z axis (inclination angle θ = θ _{8 of the} semiconductor substrate 13).

Thus, when the inclination angle θ of the semiconductor substrate 13 changes between θ ₁ ,..., Θ ₈ , the illumination angle of the test object 1 also changes in the same manner. Hereinafter, the illumination angle of the test object 1 is represented by θ.
Next, this observation method will be described.
As shown in FIG. 2, the present observation method includes steps S1 to S5. Hereinafter, these steps will be described in order.
(Step S1)
The control circuit 20 sets the illumination angle θ to an initial value (for example, θ ₀ ) (FIG. 3A), and acquires the image data group d ₀ described above in that state (FIG. 3B). The computer 30 Fourier-transforms (temporal Fourier transform) the time variation of the electric field intensity distribution indicated by the image data group d ₀ (FIG. 3C), and forms the image plane I when the illumination angle θ = θ _0. The complex amplitude distributions Aω ₀ (i, j), Aω ₁ (i, j),... Of the generated light waves of the respective wavelengths are obtained (FIG. 3C). Among these, the complex amplitude distribution Aω ₀ (i, j) of the light wave of a specific wavelength (for example, the center wavelength of the terahertz region) is stored. Hereinafter, a light wave having a specific wavelength is simply referred to as a “light wave”, and the complex amplitude distribution Aω ₀ (i, j) of this light wave is attached with the same subscript as the set value “θ ₀ ” of the illumination angle θ. ₀ (i, j) ”(the same applies to the following).

Next, the control circuit 20 sets the illumination angle θ to the next value (for example, θ ₁ ) (FIG. 4A) to acquire the image data group d ₁ , and the computer 30 acquires the image data group d. Based on ₁ , the complex amplitude distribution A ₁ (i, j) of the light wave generated on the imaging plane I when the illumination angle θ = θ ₁ is obtained and stored.
Similarly, the control circuit 20, FIG. 4 (b), ₂ an illumination angle theta theta as shown in ..., ..., the image data group d ₂ are sequentially set into theta _8, ..., d ₈ sequentially acquires, computer 30, image data group d _2, · · ·, based on the d _8, the illumination angle θ = θ _2, ···, occurring on the image plane I at each theta ₈ A complex amplitude distribution A ₂ (i, j),..., A ₈ (i, j) of each light wave is obtained and stored.

Here, these complex amplitude distributions A ₀ (i, j), A ₁ (i, j), A ₂ (i, j),..., A ₈ (i, j) include imaging optics. A phase component Δφ (i, j) that is superimposed on each light wave in a state where the single system 14 is not present is superposed (see the dotted line in FIG. 3A).
In this step, the computer 30 calculates the phase component from each complex amplitude distribution A ₀ (i, j), A ₁ (i, j), A ₂ (i, j),..., A ₈ (i, j). Δφ (i, j) is corrected.

  Note that the phase component Δφ (i, j) to be corrected is unique to the terahertz spectroscopic imaging apparatus and is measured in advance (for example, the image data group d is acquired in a state where the test object 1 is not disposed). Based on the image data group d, the complex amplitude distribution of the light wave generated on the imaging plane I in that state is obtained, and the obtained phase component may be used as the phase component Δφ (i, j) to be corrected.) .

Next, as shown on the left side of FIGS. 5A, 5B, 5C,..., The illumination angles θ = θ ₀ , θ = θ ₁ , θ = θ ₂ ,. For each θ ₈ , the exit angle of each diffracted light generated in the test object 1 is shifted.
Therefore, at each of the illumination angles θ = θ ₀ , θ = θ ₁ , θ = θ ₂ ,..., Θ = θ _8, a light beam contributing to imaging (that is, a light beam that can pass through the imaging optical system 14). Is different.

Therefore, at each of the illumination angles θ = θ ₀ , θ = θ ₁ , θ = θ ₂ ,..., Θ = θ ₈ , the light wave generated on the pupil P of the imaging optical system 14 is also different.
Hereinafter, light waves generated on the pupil P of the imaging optical system 14 at each of the illumination angles θ = θ ₀ , θ = θ ₁ , θ = θ ₂ ,..., Θ = θ ₈ are represented by L ₀ , L ₁ , L _2, and ..., and L _8, which light waves L _0, L _1, L _2, ..., the differences of L ₈ will be described.

For the explanation, consider the following virtual system. This virtual system is a system in which the imaging optical system 14 is replaced with a virtual imaging optical system 14 'having a larger numerical aperture and the illumination angle θ is fixed at θ ₀ in the system shown in FIG. It is.
FIG. 6 shows the light waves L ₀ , L ₁ , L ₂ ,..., L ₈ generated on the pupil P of the imaging optical system 14 of the present system and the virtual imaging optical system 14 ′. The correspondence relationship with the virtual light wave L ′ generated on the pupil P ′ is shown.

As shown in FIG. 6, the light wave L ₀ corresponds to the light wave in the central region of the virtual light wave L ′.
The light wave L ₁ corresponds to a light wave in a region shifted in the + X direction from the center of the virtual light wave L ′.
The light wave L ₂ corresponds to a light wave in a region shifted in the −X direction from the center of the virtual light wave L ′.
The light wave L ₃ corresponds to a light wave in a region shifted in the + Y direction from the center of the virtual light wave L ′.
The light wave L ₄ corresponds to a light wave in a region shifted in the −Y direction from the center of the virtual light wave L ′.

The light wave L ₅ corresponds to a light wave in a region shifted from the center of the virtual light wave L ′ in the + X and + Y directions.
The light wave L ₆ corresponds to a light wave in a region shifted from the center of the virtual light wave L ′ in the −X and + Y directions.
The light wave L ₇ corresponds to a light wave in a region shifted from the center of the virtual light wave L ′ in the −X and −Y directions.

The light wave L ₈ corresponds to a light wave in a region shifted from the center of the virtual light wave L ′ in the + X and −Y directions.
Therefore, each diffraction pattern formed on the pupil P of the imaging optical system 14 by each of the light waves L ₀ , L ₁ , L ₂ ,..., L ₈ has the virtual light wave L ′ of the virtual imaging optical system 14 ′. This corresponds to a large diffraction pattern formed on the pupil P ′, which is obtained by cutting out diffraction patterns in regions shifted from each other.

5A, 5B, and 5C, the concept of each diffraction pattern formed on the pupil P by the light waves L ₀ , L ₁ , L ₂ is shown.
Incidentally, in FIG. 6, the position offset from the center of the virtual light wave L 'to a certain light waves L _i is determined by the set value theta _i of the illumination angle theta (proportional to sin [theta.).
Each set value _{θ 1, θ 2, ···,} θ 8 , each light wave L _0, L ₁ shown in FIG. 6, ..., overlap L ₈ is as small as possible, and each light wave L _0, L ₁ ,... Are optimized so that L ₈ can cover as wide a range as possible of the virtual light wave L ′ without any gaps.
(Step S2)
The computer 30 performs Fourier transform on the complex amplitude distributions A ₀ (i, j), A ₁ (i, j), A ₂ (i, j),..., A ₈ (i, j) acquired in step S1. conversion (spatial Fourier transform), and the complex amplitude distribution B ₀ (i, j) of each light wave _{L 0, L 1, L 2} , ···, L 8 shown in FIG. 6, B ₁ (i, j), B ₂ (i, j),..., B ₈ (i, j) is calculated.

7, 8 (a), and 9 (a), the concepts of the calculated complex amplitude distributions B ₀ (i, j), B ₁ (i, j), and B ₂ (i, j) are combined. The coordinates on the pupil P of the image optical system 14 are represented.
In FIGS. 7, 8A, and 9A, the data range in the X direction corresponds to the diameter of the pupil P of the imaging optical system 14 (the diameter of the exit pupil).
(Step S3)
As shown in FIGS. 8 (b) and 9 (b), the computer 30 has complex amplitude distributions B ₁ (i, j), B ₂ (i, j),..., B ₈ (i, j). data were shifted horizontal by sinθ each coordinate on the pupil P of the complex amplitude distribution after lateral shift _{B 1 (i, j),} B 2 (i, j), ···, B 8 (i, j) And the complex amplitude distribution C (i, j) of the virtual light wave L ′ generated on the pupil P ′ of the virtual imaging optical system 14 ′ is restored. FIG. 10A shows the concept of the restored complex amplitude distribution C (i, j).

Here, in principle, between the complex amplitude distributions B ₁ (i, j), B ₂ (i, j),..., B ₈ (i, j) Etc.) are equal to each other.
In practice, however, the complex amplitude distributions B ₁ (i, j), B ₂ are caused by changes in the environment of the system (such as uncertainty in the light source power during the period of changing the illumination angle θ, fluctuations in the refractive index of the optical path). There is a possibility that offsets (phase offset and amplitude offset) are superimposed on the data of (i, j),..., B ₈ (i, j).

Therefore, the computer 30 restores the complex amplitude distributions B ₀ (i, j), B ₁ (i, j), B ₂ (i, j),..., B ₈ (i, j). The data of the overlapping areas are compared (for example, the data of the area E1 of FIG. 7 and the data of the area E1 of FIG. 8, the data of the area E2 of FIG. 7 and the data of the area E2 of FIG. 9, etc.) From the data of the complex amplitude distributions B ₀ (i, j), B ₁ (i, j), B ₂ (i, j),..., B ₈ (i, j) The respective phase offset and amplitude offset are corrected. Thereby, the “step” of the data between the complex amplitude distributions B ₀ (i, j), B ₁ (i, j), B ₂ (i, j),..., B ₈ (i, j). Is resolved.
(Step S4)
The computer 30 performs an inverse Fourier transform on the complex amplitude distribution C (i, j) of the virtual light wave L ′, and the complex of the virtual light wave L ″ generated on the image plane I ′ of the virtual image forming optical system 14 ′. The amplitude distribution D (i, j) is obtained, and the concept of the complex amplitude distribution D (i, j) is shown in FIG.
(Step S5)
Based on the complex amplitude distribution D (i, j), the computer 30 calculates the virtual image of the test object 1 formed on the imaging plane I ′ by the virtual imaging optical system 14 ′ of the virtual system according to the following equation (1). Image data E (i, j) is created.

E (i, j) = D ^* (i, j) × D (i, j) (1)
FIG. 10C shows the concept of the image data E (i, j).
The computer 30 sends the image data E (i, j) to the display 40 and displays the image of the test object 1 (see FIG. 1).
Next, the effect of this system and this observation method will be described.

In this system, since the stage 21 for changing the posture of the semiconductor substrate 13 is provided, the illumination angle θ of the test object 1 is variable. For this reason, it became possible to implement the following observation method.
In this observation method, the illumination angle _{θ = θ 0, θ 1,} θ 2, ···, complex amplitudes occurring individually imaging plane I at theta ₈ Distribution _{A 0 (i, j),} A 1 ( i, j),..., A ₈ (i, j) are measured. Based on the measured complex amplitude distributions A ₀ (i, j), A ₁ (i, j),..., A ₈ (i, j), the object formed by the virtual imaging optical system 14 ′ is formed. Image data E (i, j) of the virtual image of the inspection object 1 can be created.

The numerical aperture of the virtual imaging optical system 14 ′ corresponds to the cover range of the light waves L ₀ , L ₁ , L ₂ ,..., L ₈ in FIG. Is about three times larger. Therefore, the image data E (i, j) represents the test object 1 with a high resolving power that exceeds the capability of the imaging optical system 14.
Also, to do so reliably, in this measurement method, the complex amplitude distribution _{A 0 (i, j),} A 1 (i, j), ···, A 8 a (i, j) once, the imaging optical Converted to complex amplitude distributions B ₀ (i, j), B ₁ (i, j), B ₂ (i, j),..., B ₈ (i, j) on the pupil P of the system 14 The complex amplitude distributions B ₀ (i, j), B ₁ (i, j), B ₂ (i, j),..., B ₈ (i, j) are combined while being shifted horizontally. The complex amplitude distribution C (i, j) on the pupil P ′ of the image optical system 14 ′ is restored.

In this measurement method, the phase component Δφ (i, j) is converted into each of the complex amplitude distributions A ₀ (i, j), A ₁ (i, j), A ₂ (A ₂ ( i, j),..., A ₈ (i, j) are corrected in advance, so that necessary data (complex amplitude distributions C (i, j), D (i, j)) are obtained in subsequent steps. , Image data E (i, j), etc.) can be obtained easily and with high accuracy.

In this measurement method, the complex amplitude distributions B ₀ (i, j), B ₁ (i, j), B ₂ (i, j),..., B ₈ ( Since the data of the overlapping area between i, j) is used and the “step” of the data is eliminated, the necessary data can be obtained with high accuracy regardless of the environmental change of the system being measured.
In this observation method, the set values of the illumination angle θ are nine types of θ ₀ , θ ₁ , θ ₂ ,..., Θ ₈ , and the numerical aperture of the virtual imaging optical system 14 ′ is the imaging optical system. However, the combination of the set values of the illumination angle θ is appropriately selected according to the required resolving power (it can be larger than 3 times).

In this observation method, a terahertz spectroscopic imaging apparatus using terahertz region light as illumination light is used as a microscope apparatus. Also good.
In addition, a non-scanning microscope apparatus that collects image data of the electric field intensity distribution on the imaging plane I is applied to this system, but scanning that acquires image data of the electric field intensity distribution point by point. A type of microscope device can also be applied.

It is a block diagram of this system. It is a flowchart of this observation method. It is a figure which shows a mode when the illumination angle (theta) is set to (theta) ₀ , and the data acquired in the state. It is a figure which shows each state when the illumination angle (theta) is set to (theta) ₁ , (theta) ₂ , and the data acquired in the state. It is a figure explaining the difference of the light beam which contributes to image formation, and the difference of the diffraction pattern on the pupil P when the illumination angle (theta) is set to (theta) ₀ , (theta) ₁ , (theta) ₂ . A virtual light wave L ′ generated on the pupil P ′ of the virtual imaging optical system 14 ′ and each light wave L ₀ , L ₁ , L ₂ ,..., L ₈ generated on the pupil P of the imaging optical system 14. FIG. It is a figure which shows the concept (by the coordinate on the pupil P) of complex amplitude distribution _B0 (i, j). Complex amplitude distribution B ₁ (i, j) and the concept of (by coordinates on the pupil P), is a diagram showing a state of lateral shift. Complex amplitude distribution B ₂ (i, j) and the concept of (by coordinates on the pupil P), is a diagram showing a state of lateral shift. Image formation by the virtual imaging optical system 14 ′, the concept of the restored complex amplitude distribution C (i, j), and the concept of the complex amplitude distribution D (i, j) that occurs on the imaging plane I ′ FIG. 4 is a diagram illustrating the concept of image data E.

Explanation of symbols

1 Test object 11 Femtosecond pulse laser,
12 beam expander,
13 Semiconductor substrate,
14 imaging optical system,
15 electro-optic crystal,
16 Polarizing plate,
17 CCD camera,
18 delay device,
19 High voltage power supply,
20 control circuit,
21 stage HM half mirror M mirror,
P, P 'pupil 14' virtual imaging optical system I, I 'imaging plane L light wave

Claims (16)

Microscopic observation using a microscope device that has an imaging optical system that forms an image of the light beam emitted from the illuminated specimen and that can measure the complex amplitude distribution of the light wave generated on the imaging surface of the imaging optical system A method,
Measurement that changes the illumination angle of the object to be measured and measures the complex amplitude distribution of each light wave that is generated individually on the imaging plane by each light beam emitted from the object when the illumination angle is at each value. Procedure and
Based on the complex amplitude distribution data of each light wave, calculate the complex amplitude distribution of the virtual light wave that occurs on the image plane when the imaging optical system is replaced with a virtual imaging optical system with a larger numerical aperture. The calculation procedure to
An image creation procedure for creating image data of a virtual image of the test object formed on the imaging plane by the virtual imaging optical system based on a complex amplitude distribution of the virtual light wave. Method. In the microscope observation method according to claim 1,
The calculation procedure is as follows:
A step of Fourier transforming the complex amplitude distribution of each light wave with respect to space, and calculating a complex amplitude distribution of each light wave that each light beam individually causes on the pupil of the imaging optical system;
A procedure for calculating the complex amplitude distribution of the virtual light wave generated on the pupil of the virtual imaging optical system by horizontally shifting and synthesizing the complex amplitude distribution of each light wave;
A microscope observation method comprising: a step of performing inverse Fourier transform on the complex amplitude distribution of the virtual light wave with respect to space and calculating the complex amplitude distribution of the virtual light wave generated on the imaging plane of the virtual imaging optical system. The microscope observation method according to claim 2,
In the calculation procedure,
In the synthesis, the phase offset and / or the amplitude offset caused by the variation between the light waves is corrected from the complex amplitude distribution of the light waves. In the microscope observation method according to any one of claims 1 to 3,
In the calculation procedure,
A microscope observation method characterized by using, as the data of the complex amplitude distribution of each light wave, data in which a phase component that the single unit of the imaging optical system superimposes in common on each light wave is corrected. In the microscope observation method according to any one of claims 1 to 4,
The microscope apparatus is
Illuminating means for illuminating the test object with pulsed light;
The imaging optical system for imaging a light beam emitted from the test object;
Detecting means for detecting an electric field intensity distribution of a light wave generated on an imaging surface of the imaging optical system;
The time variation of the intensity distribution within one light emission period is detected by controlling the light emission timing of the pulsed light and the detection timing, and the complex amplitude of the light wave generated on the imaging plane based on the data of the time variation. And a control means for calculating the distribution. In the microscope observation method according to claim 5,
The pulsed light is
A microscope observation method characterized by being terahertz pulse light. Illuminating means for illuminating the test object with pulsed light;
The imaging optical system for imaging a light beam emitted from the test object;
Detecting means for detecting an electric field intensity distribution of a light wave generated on an imaging surface of the imaging optical system;
The time variation of the intensity distribution within one light emission period is detected by controlling the light emission timing of the pulsed light and the detection timing, and the complex amplitude of the light wave generated on the imaging plane based on the data of the time variation. Control means for calculating the distribution;
Change means for changing the illumination angle of the test object,
The control means includes
A microscope apparatus characterized by measuring a complex amplitude distribution of each light wave that is generated individually on each imaging plane by each light beam emitted from the test object when the illumination angle is at each value. The microscope apparatus according to claim 7, wherein
The pulsed light is
A microscope apparatus characterized by being terahertz pulsed light. The microscope apparatus according to claim 7 or 8,
The control means includes
Based on the complex amplitude distribution data of each light wave, calculate the complex amplitude distribution of the virtual light wave that occurs on the image plane when the imaging optical system is replaced with a virtual imaging optical system with a larger numerical aperture. The calculation procedure to
An image creating procedure for creating image data of a virtual image of the test object formed on the imaging plane by the virtual imaging optical system based on the complex amplitude distribution of the virtual light wave; apparatus. The microscope apparatus according to claim 9,
In the calculation procedure, the control means includes:
Fourier transform the complex amplitude distribution of each light wave with respect to space, and calculate the complex amplitude distribution of each light wave that each light beam causes individually on the pupil of the imaging optical system,
A complex amplitude distribution of each light wave is synthesized by shifting laterally, and a complex amplitude distribution of a virtual light wave generated on the pupil of the virtual imaging optical system is calculated,
A microscope apparatus, wherein the complex amplitude distribution of the virtual light wave is subjected to inverse Fourier transform with respect to space, and the complex amplitude distribution of the virtual light wave generated on the imaging plane of the virtual imaging optical system is calculated. The microscope apparatus according to claim 10, wherein
In the calculation procedure, the control means includes:
In the synthesis, a phase offset and / or an amplitude offset due to variations between light waves is corrected from the complex amplitude distribution of the light waves. The microscope apparatus according to any one of claims 9 to 11,
In the calculation procedure, the control means includes:
The microscope apparatus characterized in that as the data of the complex amplitude distribution of each light wave, data in which a phase component that the single unit of the imaging optical system superimposes on each of the light waves is corrected is used. An image processing apparatus applied to the microscope apparatus according to claim 7 or 8,
Based on the complex amplitude distribution data of each light wave, calculate the complex amplitude distribution of the virtual light wave that occurs on the image plane when the imaging optical system is replaced with a virtual imaging optical system with a larger numerical aperture. Calculating means for
Image processing means comprising: image creating means for creating image data of a virtual image of the test object formed on the imaging plane of the virtual imaging optical system based on the complex amplitude distribution of the virtual light wave apparatus. The image processing apparatus according to claim 13.
The calculating means includes
Fourier transform the complex amplitude distribution of each light wave with respect to space, and calculate the complex amplitude distribution of each light wave that each light beam causes individually on the pupil of the imaging optical system,
A complex amplitude distribution of each light wave is synthesized by shifting laterally, and a complex amplitude distribution of a virtual light wave generated on the pupil of the virtual imaging optical system is calculated,
An image processing apparatus, wherein the complex amplitude distribution of the virtual light wave is inverse Fourier transformed with respect to space to calculate a complex amplitude distribution of the virtual light wave generated on the imaging plane of the virtual imaging optical system. The image processing apparatus according to claim 14.
The calculating means includes
In the synthesis, an image processing apparatus that corrects a phase offset and / or an amplitude offset caused by a variation between light waves from a complex amplitude distribution of the light waves. In the image processing device according to any one of claims 13 to 15,
The calculating means includes
An image processing apparatus characterized by using, as the data of the complex amplitude distribution of each light wave, data in which a phase component that is superimposed on the light wave in common by a single unit of the imaging optical system is corrected.

Images