JPH0886745A - Spatial-coherence type light wave reflection measuring device and light-wave echo tomographic device using same - Google Patents

Abstract

PURPOSE: To enable stably detecting the in-depth reflecting positions of an object for measurement, while removing the movable part of a reflector, by detecting the positions of the output pulses of spatial interference fringes which are formed by the splitting into two beams of light reflected from within the object for measurement and by the interference of the beams. CONSTITUTION: An object 4 to be measured which is placed on a movable stage 5 is illuminated with a light beam from a light source 1 comprising a semiconductor laser or the like, and a high-directivity light receiving system 12 is used to eliminate random scattering from the light beam reflected from the boundary layers of the object 4 which differ in in-depth refractive index, so that only reflected signal light is reflected by a beam splitter 3. An interferometer 13 splits the reflected signal light into two beams, causes interference between the beams, creates interference fringes on a one-dimensional detector (photodetector array, etc.) 7 as a space-dependent correlation function due to the spatial coherence of the two beams, and detects, as the difference in distance between spatial output pulses which arises on the detector 7, the position at which the optical path difference between the two beams is zero and the position of an optical path difference caused by the difference in space between in-depth reflecting planes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates an object to be measured with various types of coherent light such as incoherent light, low coherent light and coherent light as light sources, and the reflection distance of a reflected light wave from the object to be measured. A device for detecting a reflection intensity, in particular, a light wave reflection measuring device and a light wave reflection measuring device for measuring a reflection distance as a time-delayed pulse resulting from multiple interference corresponding to a reflection surface as a difference in position of a spatial output pulse due to multiple interference. The present invention relates to a light wave echography apparatus (light wave reflection image measuring apparatus) for examining a tissue structure or the like of a living body using the apparatus.

[0002]

2. Description of the Related Art A light wave reflection measuring apparatus (reflectometry) for measuring a phase delay of light reflected from a refractive index boundary of a light reflecting object utilizes an OTDR method by an ultrashort pulse modulation method and a wide band property by continuous light. An interferometric measurement method using an incoherent light source, a Modified-FWCW method, a step frequency sweep method, a coherence control method, and the like have been studied. The interferometric method generally has a movable part to traverse the reflecting mirror part of a Michelson interferometer, and is subject to a processing speed limitation. The frequency sweep method requires a complicated device for the light source, and the coherence control method has a problem that it is restricted by the resonator mode.

On the other hand, studies have been conducted to obtain a tomographic image from a reflected signal by using light instead of ultrasonic waves in an ultrasonic echography apparatus. Japanese Unexamined Patent Publication No. 4-174345 discloses a method of obtaining a tomographic image from the surface to a certain depth by using super luminescence light as a light source and detecting back-reflected light from a sample. By adopting the heterodyne detection in this method, it has been possible to obtain tomographic imaging in the vicinity of the tomography near the surface of the human retina and the blood vessel wall. (Science. 254, pp. 11
78-1181, 1991). However, in these methods, the light source used is limited to partially coherent light (low coherent light, short coherent light), and the processing speed is limited by the speed at which the reflection mirror section of the Michelson interferometer is swept. It has problems such as receiving.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation, and an object of the present invention is to provide a reflecting mirror used in the reflectometry by the conventional Michelson interferometer. Refraction in the object to be measured can be achieved by eliminating the moving part, stabilizing the operation, eliminating the processing speed limitation due to the moving speed of the moving part, and using various incoherent and coherent light sources. An object of the present invention is to provide a light wave reflection measuring device capable of detecting the positions of boundary surfaces having different rates. It is another object of the present invention to provide an optical wave echography apparatus that removes the influence of the scattering component peculiar to a biological sample and obtains the distribution of positions of different refractive indexes in the measured object as depth information.

[0005]

In order to solve the above-mentioned problems, the present invention provides an irradiation means for irradiating an object to be measured with irradiation light, a means for guiding the light reflected from the inside of the object to be measured to an interferometer, and a guide. Means for splitting the reflected light into two optical paths, interference means for interfering the split two light beams to form spatial interference fringes, one-dimensional photoelectric detection means for detecting the spatial interference fringes, and one-dimensional photoelectric detection And a means for obtaining a reflection point in the depth direction of the object to be measured from the position of the output pulse of the spatial interference fringes formed on the means.

Further, according to the present invention, the means for irradiating the multiple measurement object with the irradiation light, and the two light fluxes of the reference light obtained from a part of the irradiation light and the reflected light from the inside of the object to be measured are caused to interfere with each other to produce a spatial interference pattern. And a one-dimensional photoelectric detection means for detecting spatial interference fringes, and a reflection point in the depth direction of the measured object from the position of the output pulse of the spatial interference fringes formed on the one-dimensional photoelectric detection means. It is characterized by being configured by means for ascertaining.

Further, according to the present invention, the irradiation means for irradiating the object to be measured with the irradiation light, the means for moving one of the objects to change the positions of the object to be measured and the irradiation light, and the light reflected from the sample. Is divided into a plurality of regions, and the opening diameter of the divided space is increased as the degree of attenuating and removing the scattered light by the object to be measured is increased to prevent interference between different divided spaces. And a means for shifting the frequency of either the reference light obtained from a part of the irradiation light or the reflected light from the sample, and the reflected light of the two light fluxes whose frequency is shifted. , Or either one of the reference light and the reflected light whose frequency has been shifted, is formed on the one-dimensional photoelectric detection means for each space divided into a plurality of heterodyne interfering means for forming spatial interference fringes. The output pulse position of the interference fringes modulated by the generated beat component is used to obtain the reflection point in the depth direction of the object to be measured, and to calculate, process, and display the signal at the detected reflection point. The feature is that a light wave reflection distribution image of the object is obtained.

[0008]

In the Michelson interferometer which uses a short coherent light as a light source to obtain a reflection point, a reference light beam obtained by scanning a reference light reflecting mirror and a light beam reflected from an object to be measured are conventionally used. The correlation function of the two light fluxes was detected as the output of the delay time difference due to the optical path difference. Therefore, the reflecting surface was observed as an output pulse at the Kuninobu time difference. The present invention uses a time-dependent correlation function due to interference of two light fluxes as a space-dependent correlation function due to spatial interference of two light fluxes to form interference fringes on a one-dimensional detector, Characterized by observing the reflecting surface as a difference in distance between the point where the optical path difference is zero and the spatial output pulse formed on the detector corresponding to the optical path difference of the two light beams caused by the reflecting surface. Therefore, the interferometer, which does not have a moving part such as the reference reflecting mirror in the conventional Michelson interferometer and forms a spatial interference fringe, is stable in operation. Moreover, since there is no movable part, the traveling speed of the reflecting mirror in the Michelson interferometer has limited the detection processing speed of the reflecting surface, but in the present invention, the optical path difference between the two light fluxes is set on the one-dimensional detector. Since the luminous flux arrives at the speed of light, it can be almost ignored, and only the output reading speed of the one-dimensional detector limits the processing speed. That is, the processing speed is dramatically improved as compared with the conventional one. Furthermore, since the output pulse to be observed is formed as light beam interference at a position corresponding to the optical path difference, the light source is a light emitting diode, a super luminescence, a multimode laser, or the like, which has a wide spectral distribution and has various incoherent to coherent characteristics. It is possible to use up to a light source.

Further, the present invention is an interference method for spatially interfering two light fluxes to form an interference fringe on a one-dimensional detector, wherein reflected light from an object to be measured is divided into two light fluxes to form an interference fringe, As an autocorrelation function, it can be observed as an output pulse on the detector corresponding to the optical path difference between the two light beams.

Further, according to the present invention, a light source is irradiated from one direction of an object to be measured, and reflected light reflected from each point in the depth direction of the object to be measured or reference light obtained by dividing a part of the irradiation light. , The reflected light and the reference light are combined from an interferometer that forms spatial interference fringes, and the interference fringes are formed on the one-dimensional detector as a space-dependent cross-correlation function due to the spatial interference of two light beams. Boundary layers with different refractive indices in the depth direction of the object to be measured are detected by detecting the position of the beat component generated at the delayed position extended corresponding to the reflection point obtained by converting the synthesized light into the light source. The reflection position from each point can be detected with even higher sensitivity by removing the DC component which is the non-interference component.

Further, when the present invention is used as a light wave echography to obtain a distribution of points having different refractive indices in the depth direction of the measured object as an image, various coherent light beams are emitted from one direction of the measured object which is a scattering object. By doing so, the reflection position can be obtained by arranging on the one-dimensional detector from each point where the refractive index in the depth direction of the scattering object is different, so that the refraction inside the scattering object does not occur without irradiating light from all directions of the scattering object. It is possible to specify the position of each point having a different rate. That is, as a result of reflection from each point with a different refractive index inside the scattering object by itself or as a result of being superposed with the reference light, a spatial pulsed light-like bright line corresponding to each point with a different refractive index is obtained. Is reproduced as an electric signal, and the reflected light from each point in the depth direction of the scattering object can be measured with a spatial resolution of several tens of microns or less. Therefore, the number of times of light irradiation can be reduced as compared with the transmission type optical tomography apparatus.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a light source, which is composed of, for example, a super luminescence diode or a semiconductor laser. A condenser lens 2, a beam splitter 3, and an object to be measured 4 are sequentially arranged on the optical axis of the light beam generated from the light source 1. The object 4 to be measured is placed on a movable table 5 which is movable in the X, Y, and Z axis directions when the distribution of boundary surfaces having different refractive indexes is obtained. The light beam reflected from the measured object 4 is
Random scattering is removed by the highly directional light receiving system 12 (inserted as necessary), and only the reflected signal light is reflected by the beam splitter 3. On the optical axis, the reflected signal light is split into two light fluxes, an interferometer 13 for interfering the split two light fluxes to form spatial interference fringes, and a photodiode array having a one-dimensional function for detecting the spatial interference fringes. A photodetector 7 is provided as a photoelectric converter which is a two-dimensional image sensor such as a linear image sensor or a CCD camera. A signal processor 8 is connected to the output terminal of the detector 7. The signal processor 8 differs depending on the detector used, but for example, an output reading function unit 8a for spatial interference fringes formed on the array sensor and an A / D converter for converting the size thereof into a digital signal. 8b. The digital signal output from the A / D converter 8b is supplied to the computer 9. The computer 9 is connected to a memory 10 for storing the pulse signals of the time series output from the signal processor 8 and a display device 11 for displaying various information.

Interferometer 13 used in Embodiment 1 of the present invention
Can use a known interferometer that splits the reflected light from the measured object 4 into two light fluxes and forms spatial interference of the two light fluxes (Reference; Spectroscopic Study, Vol. 38, No. 6,).
p. 415-p. 424, 1989). FIG. 2 shows a triangular optical path common interferometer which is an interferometer having a doubling light source. This is the same as the known technique except that the slit 26 is provided in order to improve the contrast of the interference fringes. Three
2 is a beam splitter, 23, 24 and 25 are mirrors, 1 S ₀ is a light source, DUT is 27, L is a lens, 7
D is a multi-channel detector. This interferometer is equivalent to arranging two pinhole light sources on the focal plane of the lens 27 and observing interference fringes on the rear focal plane in order to observe Young's interference.

FIG. 3 shows a Savart plate birefringent polarization interferometer. The linearly polarized light incident parallel to the crystal plane of the Savart plate in which two birefringent crystals are combined is split into two components and emitted as parallel light. This constitutes a source doubling system like the triangular optical path common path interferometer, and the principle of forming interference fringes is also the same. Since they can be arranged in a line, they are more compact than the triangular optical path interferometer. Reference numeral 1 is a light source, and the measured object is 4. 311 shows two equivalent light sources. Three
Reference numerals 2 and 34 denote a polarizer and an analyzer, and 33 denotes a Savart plate. A lens 35 has a light source arranged on the front focal plane and a detector 7 arranged on the rear focal plane.

FIG. 4 shows a second embodiment in which an interferometer is constructed by using an optical fiber. The light from the light source 1 propagates through the optical fiber 41, and the light from the emission end of the optical fiber 41 is converted into a parallel light flux by the traversing and moving platform 5 in which a lens is arranged.
Is irradiated. Random scattered light from the measured object is removed by the highly directional light receiving system 12, and reflected light is reflected by the lens 44.
Then, the light is incident on the optical fiber 41. Coupler 3 that splits light in the same way as a beam splitter
Thus, the reflected light is propagated to the optical fiber 42. A part of the reflected light is split and propagated to the optical fiber 43 by the photocoupler, and the emission ends of the optical fibers 42 and 43 serve as the light source of the light source doubling interferometer 13. A zooming fiber fine adjustment driver 46 that can finely adjust the position of the emission end of the optical fiber 43 is arranged as necessary. The spatial interferometer 13 is
The lens 46 is disposed, the emission ends of the optical fibers 42 and 43 are disposed on the front focal plane thereof, and the multi-channel detector 7 is disposed at the rear focal point. The output of the detector 7 is processed as in Example 1.

FIG. 5 shows another embodiment. Examples 1,
Reference numeral 2 divides the reflected signal light to form interference fringes, whereas this embodiment forms interference fringes due to the reference light and the reflected signal light. The beam splitter 3 splits the light source into two light beams, and the obliquely reflecting mirror 51 forms reference light. When using heterodyne detection together, AOM 52
And a light attenuator 52 for controlling the intensity of the reference light is also arranged as necessary. Others are the same as those in the first embodiment.

FIG. 6 shows another embodiment of the reflection distance measuring method by the interference between the reference light and the reflected signal light. In FIG. 5, an optical fiber is used in which the propagation of a light wave is in free space, and a coupler is used in place of the beam splitter. By the coupler 62, the reflected signal light is transferred to one emission end of the optical fiber 67, and the reference light of the light source is transferred to the other emission end, thereby forming a double light source of the interferometer 13. A zooming fine adjustment driver 68 that can finely adjust one of the output ends of the optical fiber 67 back and forth is arranged, and a lens 69 of the spatial interferometer 13 is provided.
By changing the distance up to, the interference fringe area formed on the array detector can be zoomed. On the other side of the optical fiber, a cylindrical electrostrictive oscillator (P
A modulator represented by a ZT) 73 unit is arranged, the reference light undergoes phase modulation, and the interference fringes are processed by detecting a modulation component by the detector 7.

In the embodiment as shown in FIGS. 1 and 2, in which spatial interference fringes of signal lights are formed to detect reflection points,
The magnitude of the interference component is automatically determined by the reflectance of the surface of the measured object and the reflectance of the internal reflection surface. On the other hand, in the embodiment as shown in FIGS. 5 and 6, in which the reflection point is detected by the spatial interference fringes of the reference light and the signal light, the reference light is dimmed or the frequency is shifted to change the light intensity. There is an advantage that sensitivity can be improved by changing the size of the term of the interference component and enabling heterodyne detection. Furthermore, by changing the optical path length of the reference light, it is possible to shift the area where the interference fringes are formed, which is advantageous in that the reflection point can be zoomed.

As the light source of the present invention, a light emitting diode, a super luminescence diode, a multimode laser, etc. can be used, but the contrast of interference fringes is different. The contrast of the interference fringe is the temporal coherence coefficient,
It is determined by the phase coherence coefficient (spatial coherence coefficient) and the amplitude ratio of the two-beam interference light. Of these, the temporal coherence coefficient is determined by the spectral distribution of the light source used, and is generally given by the Fourier transform of the spectral distribution. When the spectral distribution of light is wide, the temporal coherence coefficient determined by the optical path difference of the two-beam interference light has a correlation only when there is no optical path difference of the two beams that interfere with each other. Further, the phase coherence coefficient (spatial coherence coefficient) is 1 in the case of coherence light such as a laser, but in the case of a low coherence light source or an incoherence light source, it becomes smaller as the spatial spread of the light source increases. The super luminescence diode and the light emitting diode are generally smaller than 1 unless the light emitting place is approximated to a point light source. Next, the amplitude ratio of the two-beam interference light represents an interference term, and improving the contrast increases the S / N ratio. The intensity of the reflected light from the measured object depends on the object. There are two ways to improve the contrast. First, the reflected signal light is much smaller than the reference light. In this case, the shot noise component can be approximated to only the reference light component, and like the heterodyne detection of coherence optical communication, the S / N ratio depends on only the shot noise component of the reflected signal. have.
In this case, nothing special is done to increase the S / N ratio. Second, the reflected signal light is weaker than the reference light, but the difference is not extreme. In this case, the shot noise component is composed of both the reference light component and the signal light component. At this time, the interference light component has a maximum value of 1 when the amplitudes of the two light fluxes are equal, and the S / N ratio also becomes the “shot noise limit” S / N ratio. Therefore, the intensity of the reference light can be adjusted to be about the same as the intensity of the reflected signal light and the intensity of the reference light by adjusting the reflectance of the reflecting mirror and the dimming rate of the dimmer inserted in the optical path. The S / N ratio can be increased.

Next, the case where the heterodyne detection is used in the present invention will be described. When the method of the present invention is applied to a biological sample, the reflected light from the sample is composed of random scattered light from the inside of the medium and reflected light reflected from the boundary of each layer having a different refractive index. Of these, random scattered light can be removed by performing heterodyne detection or by receiving light with a highly directional light receiving system. This principle and configuration are described in Japanese Patent Application No. 1-62898 and Japanese Patent Application No. 1-25.
No. 0034, Japanese Patent Application No. 1-250036, Japanese Patent Application No. 2-7
7690. In order to detect with high sensitivity even when there are few scattered components, it is desirable to use heterodyne detection together. When processing time-sequential signals like a conventional Michelson interferometer, the signal component generated at the time when the reflecting mirror of the Michelson interferometer and the reflecting surface of the object to be measured are interference components, and the beat frequency is pulse-shaped. The output is modulated to. The present invention forms a signal component on the detector corresponding to the distance at which the reflected light from the object to be measured and the reference light coincide with each other, and the beat frequency becomes a pulse-modulated output, so the maximum response of the detector is obtained. The frequency is set higher than the beat frequency of heterodyne detection. In this way, the beat signal from the detector is obtained by the band pass filter, the square detection and the low pass filter, and the divergence value of the magnitude is calculated by the logarithmic amplifier. Others, the processing of the signal is the same as the description of FIG.

Since the heterodyne detection is performed on the reference light and the signal light reflected from the sample, various known frequency shift methods can be used as means for shifting the frequency of either one of the light. The first embodiment of the present invention shows an example in which an ultrasonic shifter is inserted in the reference optical path.
In the second embodiment in which the Michelson interferometer is formed by using the optical fiber, a case of shifting the frequency by changing the length of the optical fiber by using the phase love adjuster of the cylindrical electrostrictive oscillator (PZT) is described. Shows.

FIG. 7 shows an embodiment of a lightwave echography apparatus in which a plurality of interferometers are arranged. In this example,
An example is shown in which the reference light from the light source 1 and the interference of the reflected signal light from the measured object 4 are used. The light from the light source 1 is split into two light beams by the coupler 72a, and one of them is subjected to phase modulation as a reference light by a cylindrical electrostrictive oscillator (PZT) 73 and becomes a light source of the interferometer 713. The other passes through the coupler 72b and is irradiated by the optical scanner 75 onto the measured object 4 such as a living body. The random scattered light is removed by the highly directional light receiving system 12, and only the reflected signal light is received by the optical fiber arranged in the optical scanner, and a part of it becomes the light source of the interferometer 13 via the coupler 72b. . The interference fringes are detected by the detector 7. Detector 7
The output of is modulated with the frequency of PZT, so that the modulated component is detected and processed. The above processing is arranged in parallel and displayed as an image.

Next, the image creation and process for obtaining tomography will be described. First, the spatial resolution and depth resolution of the light wave echo image are determined as follows. That is,
The spatial resolution (ΔZ) in the depth direction, that is, the Z-axis direction is determined by the total spectral width of the multimode. The spatial resolution (ΔY × ΔX) of the incident cross section is substantially determined by the diameter of the incident light and the optical heterodyne detection aperture angle.

The signal waveform of the array detector including the data in the depth direction of the object to be measured for obtaining the position of the array detector where the beat signal is generated as a function of the reflection signal is stored in the memory 10 via the computer 9 line by line. Memorized in. After that, the movable table 5 is moved along the Y-axis by the cross-sectional diameter of the incident light and the same measurement is performed.
Sequential measurement is performed over the entire range in the Y-axis direction.

As described above, the digital data stored in the memory 10 is read out by the computer 9, and by the well-known image processing technique, for each section of the spatial resolution (ΔY × ΔZ) of the measured object 4, It is processed into a grayscale image or a color-based image according to the digital amount. The processed grayscale image or color-based image is supplied to the display device 11 and displayed. In this way, by displaying the data of the entire ZY plane of the measured object 4 on the display device 11, it is possible to obtain a high-resolution tomographic image including the data in the depth direction in spite of the unidirectional measurement from the uniaxial direction. You can

If the above measurement is also performed in the X-axis direction, it is possible to obtain a multi-layered tomographic image of the object 4 to be measured. Therefore, when the measurement is also performed in the X-axis direction as described above, the data in the three-dimensional depth direction of the measured object 4 is stored in the memory 10. Therefore, by changing the reading direction of the memory 10, It is possible to generate a tomographic image of the measurement object 4 that is cut from any direction.

The present invention is directed to the measurement of coatings such as semiconductors and optical ICs.
It can be used for diagnostic measurement by reflected waves such as, and for biological echography. Moreover, in the microwave region as well as in the light region, if it is an electromagnetic wave reflecting object,
It is possible to quickly and non-invasively observe a multilayer tomographic image of a living body, a crystal, a semiconductor, a composite material, and the like, and it is possible to apply to medical diagnostics and structural measurement of an engineering department.

Although the spatial interference type light wave reflection measuring apparatus of the present invention has been described based on the embodiments, the present invention is not limited to the following embodiments and various modifications can be made. In particular, interferometers are of various types that form interference fringes spatially,
For example, various types such as a wavefront splitting interferometer using a double prism and an interferometer that is equivalently a Young's interferometer can be used. Further, by using a plurality of interferometers, the parallel spatial light interference reflection measuring device of the parallel type that simultaneously detects a plurality of reflecting surfaces can be implemented by arranging these various interferometers in parallel. Of course.

[0029]

INDUSTRIAL APPLICABILITY The present invention irradiates an object to be measured with various coherent light such as incoherent light, low coherent light, and coherent light as a light source, respectively, and results of multiple interference corresponding to a reflecting surface in the object to be measured. Since the generated time-delayed pulse is detected by the multi-channel detector as the difference in the position of the spatial output pulse by using the interferometer, the signal processing can be performed at high speed. In particular, when heterodyne detection is used in combination, it can be applied to the detection of biological samples with a large amount of scattering, etc., or to the equatmography device using light, because high-speed detection can be performed more easily than with conventional methods, and parallel processing becomes easier and a practical device can be provided. Becomes

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a spatial interference type optical wave reflection measuring apparatus by interference of signal lights using a multimode laser according to the present invention and an optical wave echography using the same.

FIG. 2 is a diagram showing a Savart plate birefringent polarization interferometer used as the interferometer in the embodiment of FIG.

3 is a diagram showing a triangular optical path common path interferometer used as an interferometer in the embodiment of FIG.

FIG. 4 shows a second embodiment of a spatial interference type light wave reflection measuring apparatus by interference between signal lights using an optical fiber and a photocoupler.

FIG. 5 is a basic configuration diagram showing a third embodiment of a spatial interference type light wave reflection measuring apparatus by interference between signal light and reference light.

FIG. 6 is a configuration diagram showing a fourth embodiment of a spatial interference type light wave reflection measuring device by interference between signal light and reference light using an optical fiber and a photocoupler.

FIG. 7 is a configuration diagram showing a fifth embodiment of a parallel spatial interference type light wave reflection measurement apparatus using interference between signal light and reference light using an optical fiber and a photocoupler.

[Explanation of symbols]

 1. ... Light source 2. ... Condensing lens 3. ... Beam splitter 4. ... Object to be measured 5. ... Movable platform 7. ... One-dimensional photodetector 8. ... Signal processing unit 8a. ..Bandpass filters 8b. ..Detectors 9. ... Computer 10. ..Memory 11. ..Display device 12. ..Highly directional light receiving system 13. ..Interferometers 23. ..Mirror 24. ..Mirror 25. ..Mirror 26. ..Slits 27. ..Lens 32. ..Polarizer 33. ..Savart plates 34. ..Analyzer 41. ..Optical fiber 42. ..Optical fiber 44. ..Trailing platform 45. ..Lens 51. ..Mirror 52. ..AOM 53. ..Dimmer 63. ..PZT 68. ..Fine adjustment driver for zooming 72a. -Photocoupler group 72b.・ Photocoupler group 73. ..PZT group 713.・ Spatial interferometer group 75. ..Optical scanner 712.・ High directivity group

Claims (8)

[Claims] 1. An irradiation unit that irradiates an object to be measured with irradiation light, a unit that guides reflected light from the inside of the object to be measured to an interferometer, and a unit that divides the guided reflected light into two light beams. From the position of the output pulse of the spatial interference fringes formed on the interfering means for interfering the two light beams to form the spatial interference fringes, the one-dimensional photoelectric detection means for detecting the spatial interference fringes A spatial interference light wave reflection measuring apparatus comprising: a means for obtaining a reflection point in the depth direction of an object to be measured; 2. A means for irradiating a multiple measurement object with irradiation light,
Interference means for forming spatial interference fringes by interfering two light beams of the reference light obtained from a part of the irradiation light and the reflected light from the inside of the measured object, and a one-dimensional photoelectric detection means for detecting the spatial interference fringes, A spatial interference type optical wave reflection measuring apparatus comprising: a means for obtaining a reflection point in the depth direction of the object to be measured from the position of the output pulse of the spatial interference fringes formed on the one-dimensional photoelectric detecting means. . 3. A means for shifting the frequency of one of the reference light and the reflected light, and a reflected light of two light fluxes in which the frequency of the one is shifted, or a frequency of either one of them. The reference light and the reflected light
Heterodyne interference means for interfering to form spatial interference fringes, one-dimensional photoelectric detection means for detecting a heterodyne interference signal of the spatial interference fringes, and interference fringes modulated by beat components formed on the one-dimensional photoelectric detection means 3. The spatial interference light wave reflection measuring apparatus according to claim 1 or 2, further comprising means for obtaining a reflection point in the depth direction of the object to be measured from the output pulse position. 4. The interference means for forming spatial interference fringes is a light source doubling interferometer using a triangular common path interferometer, or a reflected light is propagated through two optical fibers by a photocoupler to emit light from each end face of the optical fibers. The spatial interference type light wave reflection measuring apparatus according to claim 1, wherein the light source doubling interferometer is configured to form interference fringes by means of. 5. A birefringent polarization interferometer using a birefringent substance, as an interfering means for forming spatial interference fringes, a square common path interferometer, a reflector tilted Michelson interferometer, a reflector tilted Fabry-Perot interferometer, or a birefringent substance. The interferometers are used to form equal-thickness interference fringes.
The spatial interference type light wave reflection measuring device described. 6. An interfering unit for interfering a reference light beam obtained from a part of the irradiation light beam and a reflected light beam from the inside of the object to be measured to form a spatial interference fringe, the reference light beam and the reflected light beam are photocoupler. 3. The spatial interference type light wave reflection measuring apparatus according to claim 2, which is a light source doubling interferometer that propagates the optical fiber by means of the light and forms an interference fringe by the light emitted from the end face of the optical fiber. 7. A phase difference between two light fluxes forming a spatial interference fringe is controlled by changing an optical path length difference between one light flux of the two interfering light fluxes and the other light flux to a surface where interference fringes are formed. The spatial interference type light wave reflection according to claim 1 or 2, wherein the output pulse position of the interference fringes formed on the one-dimensional photoelectric detection means is spatially moved, and the reflection position can be selectively zoomed. measuring device. 8. An irradiation unit that irradiates an object to be measured with irradiation light, a unit that moves either one of the objects to change the positions of the object to be measured and the irradiation light, and propagation of light reflected from the sample. The area is divided in a complicated manner, and the opening diameter of the divided space is increased as the degree of attenuating and removing the scattered light by the object to be measured is increased, so that interference between different divided spatial areas does not occur. Means, means for shifting the frequency of any one of the reference light or the reflected light from the sample obtained from a part of the irradiation light, and the reflected light of the two light fluxes whose frequency is shifted, or The reference light and the reflected light whose frequency has been shifted by one of them interferes with each other to form spatial interference fringes, and a beat formed on the one-dimensional photoelectric detection means for each of the plurality of divided spaces. Success The optical wave of the measured object, which is composed of means for obtaining the reflection point in the depth direction of the measured object from the output pulse position of the interference fringes modulated by minute and means for calculating, processing and displaying the signal of the detected reflection point. An optical wave echography apparatus characterized by obtaining a reflection distribution image.