JPH10267830A - Optical measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical measuring device by which a necessary data can be measured in a short time. SOLUTION: An optical demultiplexer/multiplexer for dividing a reference light and a modulation mechanism for reference light for modulating the divided lights differently are provided in an optical measuring device using a short coherent long light, so that a demultiplexed light of reference light and measuring light which enter a photoelectric converter 40 is made to include informations converning a plurality of measuring points (four points in the right diagram) with different depths. Then a computer 51 calculates the optical characteristic data concerning the multiple measuring points according to the output of the photoelectric converter 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical measuring device for measuring an optical characteristic of a sample, for example, an optical measuring device used for inspecting an internal structure of a biological sample.

[0002]

2. Description of the Related Art In recent years, various techniques capable of nondestructively inspecting the internal structure of a sample have been developed and have been used in various fields. As one of such techniques, optical coherence tomography (OCT) for obtaining a tomographic image or the like of a sample using light having a short coherent length is known.

[0003] The outline of OCT will be described below. The OCT uses an optical measurement device including a light source that generates light having a short coherent length (about ten and several μm), an interferometer including an optical multiplexer / demultiplexer, a movable reflection mirror, and a scanning system, and an analysis system.

[0004] Short coherent long light generated by a light source in the optical measuring apparatus is introduced into an optical multiplexer / demultiplexer constituting an interferometer, and is separated into measurement light and reference light. The measurement light passes through a scanning system for changing the position where the measurement light is introduced into the sample.
The measurement light introduced into the sample (for example, the eye) and reflected in the sample is returned to the optical multiplexer / demultiplexer via the scanning system. On the other hand, the reference light returns to the optical multiplexer / demultiplexer after being reflected by the reflecting mirror that is moving back and forth in the optical axis direction of the reference light in a distance range corresponding to the measurement range of the sample, and is reflected by the optical multiplexer / demultiplexer. Multiplexed with the reflected light from the sample. In addition, as the movement pattern of the reflection mirror, usually, in order to facilitate the processing in the analysis system, after moving at a constant speed from the start point to the end point of the distance range, return to a high speed to the start point. A pattern in which there is a time zone in which the reflecting mirror moves at a constant speed is used.

[0005] The analysis system is a process for determining the correspondence between the degree of modulation applied to the light multiplexed by the optical multiplexer / demultiplexer and the position of the reflection mirror (the depth of the portion where the measurement light is introduced, For obtaining optical characteristic data at several different locations) and storing the results. When obtaining a cross-sectional image perpendicular to the optical axis of the measurement light, the measurement light is introduced to each position where measurement is required by the scanning system, and the optical characteristics data at each position is calculated and stored by the analysis system. Will be Then, after acquiring a plurality of optical property data, the analysis system creates and displays a cross-sectional image based on the optical property data.

That is, in the OCT optical measuring apparatus, a specific portion is reflected from a plurality of lights which are simultaneously incident on the optical multiplexer / demultiplexer and which are reflected at a plurality of places having different depths in the sample. Short coherent long light is used to identify the reflected light. More specifically, as a result of being reflected at different depths, the light arriving at the optical multiplexer / demultiplexer at the same time is a short coherent long light having a different separation time at the optical multiplexer / demultiplexer from the original measurement light. Therefore, of those lights that interfere with the reference light from the reflection mirror side,
Only the reflected light resulting from the measurement light separated by the optical multiplexer / demultiplexer at the same time as the reference light, that is, the light reflected at a position where the optical path length of the measurement light becomes equal to the optical path length of the reference light is included.
Since the wavelength of the reference light is shifted due to the movement of the reference mirror, the light multiplexed by the optical multiplexer / demultiplexer includes the optical path length of the reference light at that time in the sample (at the position of the reference mirror). This is light that has been modulated according to the magnitude of the measurement light component that represents the optical characteristics at the depth determined by the correlation. For this reason, the analysis system analyzes the degree of intensity modulation of the light multiplexed by the optical multiplexer / demultiplexer in relation to the position of the reflection mirror, and thereby analyzes the optical characteristics at each depth of the portion where the measurement light is introduced. Can be requested. In OCT, a measurement based on such a principle is repeated at various points on a sample, and a two-dimensional image or a three-dimensional image of the sample is obtained.

[0007] References relating to the OCT technique include:
D. Huang et al., "Optical Coherence Tomography", Sci
1991, 254, pp. 1178-1181 and so on.

[0008]

As is clear from the above description, the spatial resolution of an OCT optical measuring device (hereinafter simply referred to as an optical measuring device) basically depends on the light used for measurement. Is determined by the coherent length of For this reason, the ultrasonic measurement technology (10 MH, which is a general measurement condition)
Spatial resolution at the time of z measurement: about 150 μm, laser scanning microscope technology (spatial resolution at the time of fundus part measurement: about 200 μm)
As compared with other measurement techniques such as m), measurement with high spatial resolution is possible.

However, the conventional optical measuring apparatus is a single-channel apparatus that can measure only one point existing on the optical axis of the measuring light at a certain time, so that a plurality of points having different depths can be measured. It was a device that took a long time to measure. The fact that measurement takes a long time is a problem from the viewpoint of cost performance,
Further, when the measurement target sample is difficult to maintain the same position for a long time like a biological sample, a problem in measurement accuracy is also induced. For example,
When the eyeball is the measurement target, the relative positional relationship between the optical measurement device and the sample to be measured may fluctuate due to movement of the head of the subject or slight movement of the eyeball. In the conventional optical measurement device, a relatively long time is required to finish the measurement in the target range, and during that time, the positional relationship fluctuates, and optical characteristic data other than the target position is measured. It happened frequently.

[0010] Therefore, an object of the present invention is to provide an optical measuring device capable of measuring necessary data in a shorter time.

[0011]

According to the present invention, there is provided an optical measuring apparatus capable of simultaneously measuring a plurality of points on an optical axis of a measuring beam.

According to a first aspect of the present invention, there is provided a light multiplexing means for multiplexing incident light, a light generating means for generating light having a short coherent length, and a light generating means for generating light having a short coherent length. A light separating means for separating the measuring light and the first to N-th reference lights, and modulating the first to N-th reference lights separated by the light separating means with patterns different from each other. A reference light introducing means for introducing the applied first to N-th reference lights into the optical multiplexing means, and a measuring light reflected and scattered by the measuring sample while introducing the measuring light separated by the light separating means into the measuring sample. Measuring light introducing means for introducing the light into the optical multiplexing means, photoelectric conversion means for outputting an electric signal of a level corresponding to the intensity of the light multiplexed by the optical multiplexing means, and the first to Nth reference light introducing means Using the amount of modulation applied to light, From the electric signal output from the electric conversion means, the first to N-th reference light existing at a position corresponding to the optical path length from the light separation means to the optical multiplexing means of the first to Nth reference lights at that time in the sample to be measured. An optical measurement device is configured by using a calculation unit that calculates optical characteristic data regarding the N-th measurement point.

In the optical measuring device according to the first aspect having such a configuration, the I-th (I = 1 to I)
N) the reflected light from a portion existing at a position corresponding to the optical path length from the light separation means to the optical multiplexing means of the reference light, the multiplexed light of the I-th reference light, and the multiplexed light of another reference light Will be modulated in a different pattern. That is, the light output from the optical multiplexing / demultiplexing means includes information indicating the optical characteristics of N measurement points having different depths in a discriminable form.
Therefore, the calculating means can simultaneously calculate the optical characteristic data of the N measurement points based on the time change pattern of the electric signal output by the photoelectric conversion means.

As described above, according to the present optical measurement device, the optical characteristic data of a plurality of measurement points can be measured at the same time.
The measurement can be completed in a shorter time as compared with a conventional optical measurement device. In addition, since the optical characteristic data for a plurality of measurement points are measured at the same time, the relative positional accuracy of the measurement points in the depth direction is extremely high.

In realizing the first optical measuring device, various configurations of reference light introducing means can be adopted. For example, the first to N-th reflectors provided at positions where the first to N-th reference lights separated by the light separating means are incident, and the first to N-th reflectors reflected by the first to N-th reflectors, respectively.
Or introducing means for introducing the N-th reference light into the optical multiplexing means;
By controlling the positions of the first to Nth reflectors,
Reference light introducing means including reflector position control means for performing different patterns of modulation on the first to Nth reference lights can be used.

In the case where the reference light introducing means having such a configuration is used, each of the first to N-th reflectors is a reflector having a rotation axis on which the reference light is incident on a side surface, and Using a reflector having a shape in which the distance from the center of the rotation axis of the side surface on which the reference light is incident changes according to the rotation angle of the rotation axis, and as a reflector position control means, the rotation angle of the rotation axis of each reflector Can be used.

Further, the first to N-th reflectors are fixed to the same rotation axis, and the reference light is incident on the side surface, and the center of the rotation axis of the side surface on which the reference light is incident, respectively. It is also possible to use a reflector having a shape in which the distance from the reflector changes in accordance with the rotation angle of the rotating shaft and at a rate different from the rate of change in the distance of the other reflectors.

Further, when forming the optical measuring device of the first aspect, a first to N-th reflectors attached to a fixed member having a rotation axis so that the distances from the rotation axis are different from each other; The first to Nth reference lights reflected by the first to Nth reflectors are introduced into the optical multiplexing means, and different patterns are formed on the first to Nth reference lights by controlling the rotation angle of the rotation axis. Reference light modulation means including reflector position control means for performing the above-mentioned modulation can also be used.

When the reference light modulation introducing means having such a configuration is used, the first to N-th reflectors are respectively
A cylindrical mirror is used, or the first to N-th reflectors are rotatably attached to a fixed member, and the position of the fixed member is controlled as reflector position control means, and the first to N-th reflectors are controlled. It is desirable to use means for controlling the angles of the first to N-th reflectors with respect to the fixing member so that the reflecting surface faces in a direction corresponding to the inclination of the fixing member.

Each of the first to Nth electrostrictive elements partially wound around the first to Nth electrostrictive elements for introducing the first to Nth reference lights separated by the light separating means into the optical multiplexing means.
A reference light introducing unit including an N th optical fiber and electrostrictive element control means for controlling the first to N th electrostrictive elements such that different modulations are performed on the first to N th reference light. Means may be used, and reference light introducing means including an acousto-optic element for modulating the reference light may be used.

Further, by changing an optical medium having a refractive index distribution provided on the optical path of the first to N-th reference lights and changing the relative position of the optical medium with respect to the optical path of the first to N-th reference lights. Reference light introducing means including optical medium position control means for performing modulation of patterns different from each other on the first to N-th reference lights can also be used.

According to a second aspect of the present invention, there is provided an optical multiplexing means for multiplexing incident light, and a light generating means for generating first to N-th lights having short coherent lengths and different wavelengths from each other. And the first to Nth light generated by the light generating means.
A light separating unit that separates the light into a reference light and a measurement light to generate first to N-th reference light and the first to N-th measurement light, respectively; The reference light introducing means for modulating the N reference light and then introducing the modulated light into the optical multiplexing means, and the first to Nth measurement lights separated by the light separating means are introduced into one point of the sample to be measured, and the sample to be measured is Measuring light introducing means for introducing the first to Nth measuring lights reflected and scattered by the optical multiplexing means, and photoelectric conversion means for outputting an electric signal of a level corresponding to the intensity of the light multiplexed by the optical multiplexing means And a modulation pattern to be applied to the first to N-th reference lights by the reference light introducing means, and information on the wavelengths of the first to N-th reference lights. ,
Calculating means for calculating optical characteristic data relating to the first to N-th measurement points located at positions corresponding to the optical path lengths from the light separating means of the first to N-th reference lights to the optical multiplexing means at that time. The optical measuring device is configured using the optical measuring device.

That is, in the second aspect of the present invention, the means for generating the first to N-th lights having different wavelengths from each other is adopted as the light generating means, so that the means having a complicated configuration as the reference light introducing means is provided. Even if not used, modulation of different patterns is performed on the multiplexed light related to each reference light.

With the optical measuring device of the second aspect, the optical characteristic data of a plurality of measuring points can be measured at the same time. Therefore, similar to the optical measuring device of the first aspect,
Data with extremely high relative position accuracy in the depth direction can be obtained.

In configuring the optical measuring apparatus according to the first and second aspects, when an electrical signal for calculating optical characteristic data is acquired by the calculating means as the reference light introducing means, the first to Nth optical signals are obtained. It is assumed that the variation widths of the first to Nth reference optical path lengths, which are the optical path lengths of the reference light from the light separation means to the optical multiplexing means, are each about the coherent length of the light generated by the light generation means or less. Means for maintaining may be used.

In order to limit the variation width of the reference light path length, reference light path length changing means for changing the first to Nth reference light path lengths may be added. Further, in the case of limiting the variation width, a sinusoidal frequency modulation whose amplitude is set so that the DC component included in the electric signal output by the photoelectric conversion unit becomes “0” is performed.
It is desirable to employ reference light introducing means for applying to the first to N-th reference lights.

Further, when configuring the optical measuring device of the first and second aspects, detecting means for detecting a modulation pattern given to each reference light by the reference light introducing means is added, and photoelectric conversion is performed as calculating means. Means may be used for calculating optical characteristic data relating to the first to Nth measurement points using the electric signal output by the means and the detection result of the detection means.

Further, a measuring light introducing position changing means for changing the introducing position of the measuring light by the measuring light introducing means to the sample to be measured, and a form in which the order of use can be obtained from the introducing position information which is information indicating the introducing position. In addition to adding a storage unit for storing the measurement light introduction position changing unit based on the position information stored in the storage unit as a calculation unit, the measurement unit stores the introduction position information in the storage unit. The optical measurement device according to the first or second aspect may be configured by using means for calculating optical characteristic data relating to a point.

Further, as the storage means, means for storing the introduction position information and the measurement time information in a form in which the order of use can be used is adopted, and as the calculation means, for each measurement point in which the introduction position information is stored in the storage means. The optical measuring device is configured to employ means for calculating optical characteristic data using the electric signal output by the photoelectric conversion means during a time corresponding to the measurement time information associated with the measurement point. May be.

[0030]

Embodiments of the present invention will be specifically described below with reference to the drawings. <First Embodiment> FIG. 1 shows a configuration of an optical measuring apparatus according to a first embodiment. First, the function of each element constituting the optical measurement device according to the first embodiment will be described with reference to FIG.

The optical measuring apparatus according to the first embodiment is an apparatus for measuring an eye, and includes a light source 10 and a light source 16 as illustrated. The light source 10 is a light source that generates light used for measurement, and has a wavelength of approximately 830 nm and a coherent length of approximately 10 μm (hereinafter, referred to as short coherent long light). -It is configured using a luminescence diode (SLD). The light having a wavelength of 830 nm is used for the measurement because such light in the near infrared region does not damage the tissue of the eye to be measured, and
This is because the degree of penetration into the tissue is good. Further, the light source 10
The light source is a light source that can be turned on / off by a digital signal, and is connected to the computer 51 by a signal line (not shown).

The light source 16 is a light source that emits visible light, and is constituted by a semiconductor laser that emits light having a wavelength of 633 nm. An optical multiplexer 18 is provided on an optical path 20 from which the light source 10 outputs short coherent long light. A total reflection mirror 17 is provided on an optical path 26 from which the light source 16 outputs visible light. Optical multiplexer 18
Represents the light incident from the optical path 20 side as it is (optical path 2
The light source 16 and the total reflection mirror 17 are a light circuit using a half mirror, which travels straight (in one direction) and guides light incident from below in the figure toward the optical path 21.
From the optical multiplexer / demultiplexer 18 so that light from the
Is placed against.

That is, the light source 16, the total reflection mirror 17,
The optical multiplexer 18 is on the same optical path as the short coherent long light,
The light source 16 is an element for placing visible light (so-called aiming beam), and is driven when confirming that short coherent long light is irradiated to a target position of the measurement sample. Therefore, when light in the visible light region is used as the short coherent long light (when the object to be measured can irradiate such light), the optical measurement apparatus is configured without these elements. You can do it. Also, when using a CCD camera or the like for visualizing and observing the short coherent long light reflected and scattered in the sample to be measured, the optical measuring device can be configured without providing these elements. I can do it.

An optical multiplexer / demultiplexer 11 is provided on the optical path 21. The optical multiplexer / demultiplexer 11 is also an optical circuit using a half mirror. The optical multiplexer / demultiplexer 11 separates the short coherent long light incident from the optical path 21 side and emits it onto the optical paths 22 and 23. , Optical path 22 and optical path 2
Light incident from the three sides is combined (combined) and emitted onto the optical path 24. Hereinafter, of the short coherent long light split by the optical multiplexer / demultiplexer 11, light emitted on the optical path 22 is referred to as measurement light, light emitted on the optical path 23 is referred to as reference light, and emitted on the optical path 24. The light to be emitted is referred to as interference light.

The scanning optical system 12 is provided on the optical path 22. The scanning optical system 12 is an optical system provided with a mechanism for changing a measurement light introduction position (measurement site). The operation of the scanning optical system 12 can be controlled by an external device, and is controlled by a signal from a computer 51.

On the optical path 23, an optical multiplexer / demultiplexer 15, lens systems 13a to 13d, and a reference light modulator 30 are provided. The reference light modulator 30 includes reflectors 14a to 14d,
Reflector drive mechanisms 31a-31d and position sensors 50a-
50d.

The optical multiplexer / demultiplexer 15 separates the reference light incident via the optical path 23 into four reference lights, and separates the reference light into four reference lights.
The optical circuit emits the light from the optical paths 25a to 25d and emits the combined light from the optical paths 25a to 25d to the optical path 23. On each of the optical paths 25a to 25d, a lens system 13a to
13d and reflectors 14a to 14d form an optical path 25x (x = a
-D), the separated reference light emitted above passes through the lens system 13x and is reflected by the reflector 14x.
And the optical path length of the reference light to which the reflectors 14a to 14d relate when the reflector driving mechanisms 31a to 31d described later do not function in a form in which the light enters the optical multiplexer / demultiplexer 15 through Different from each other, they are arranged in the optical measuring device.

The reflector driving mechanisms 31a to 31d are mechanisms for controlling the positions of the reflectors 14a to 14d, which are total reflection mirrors, in accordance with the driving profile instruction data, and include piezo elements and their driving circuits. Reflector drive mechanism 31a
Prior to the actual operation, the computer 5
From 1 is provided drive profile indication data that causes the reflectors 14a-14d to move at different speeds. And the drive circuit in each reflector drive mechanism 31 is:
When the start of operation is instructed from the computer 51, the control of the piezo element is started in accordance with the drive profile instruction data already given.

The position sensors 50a to 50d are respectively
Reference positions of the reflectors 14a to 14d (reflector driving mechanism 31
Is a sensor that outputs digital data (position information) indicating a displacement from the position when the position sensor is not operating). As shown in the figure, the position information output from each position sensor 50 is supplied to a computer 51. ing.

On the optical path 24 side, a photoelectric converter 40 for outputting a current signal of a level corresponding to the intensity of the incident light is provided. An amplifier 42,
BPF (Band-Pass Filter) 43, A
A signal processing circuit 41 including an / D converter 44 is provided, and the A / D converter 44 is connected to the computer 51.

The photoelectric converter 40 is a circuit composed of an avalanche photodiode and a driving circuit thereof. The current signal of a level corresponding to the intensity of the interference light output from the photoelectric converter 40 is converted into a voltage signal and amplified by an amplifier 42 in a signal processing circuit 41. The BPF 43 passes only an AC component whose frequency is in a predetermined region, which is included in the voltage signal output from the amplifier 42. The pass band of the BPF 43 is set in accordance with the drive profile instruction data that may be given to the drive control mechanism 31 (the reflector control mechanism 3 depends on the pass band of the BPF 43).
1 is limited in the content of the drive profile instruction data that can be given to one). The A / D converter 44
In response to an instruction from the computer 51, a process of converting an analog voltage signal output from the BPF 43 into a digital signal is performed.

The computer 51 stores a measurement sequence file creation program, a measurement program, a data processing program, data relating to the optical path length when each reflector 14 is at the reference position, and the like. The measurement sequence file creation program interactively creates a measurement sequence file consisting of four types of drive profile designation data, three-dimensional coordinate data for several points to be measured, and measurement time designation data for each measurement point. It is a program to do.

The measurement program is a program that is started when the measurement is actually performed. When the measurement program is started, the computer 51 determines the measurement conditions based on the data in the measurement sequence file specified by the operator. In addition, the procedure is recognized, and optical characteristic data for each measurement point is measured. Then, a measurement data file storing the measurement results is created, and the measurement program ends. The data processing program is a program for outputting data stored in the measurement data file to the monitor 52 or the printer 49 in the form of a two-dimensional image, a three-dimensional image, or raw data. .

Hereinafter, the overall operation of the optical measuring apparatus according to the first embodiment will be described. A person (operator) who performs measurement using the optical measurement apparatus executes the measurement sequence file creation program prior to the actual measurement, thereby obtaining the 4
The computer 51 creates several (at least one) measurement sequence files including various kinds of drive profile designation data and a plurality (at least one) of measurement condition data.
Store it internally.

In principle, the drive profile designation data includes type designation data indicating the type of the drive profile,
It consists of cycle data defining the cycle and data defining the amplitude. In the optical measuring device of the present embodiment, as the type designation data, there are prepared data in which the position of the reflector 14 changes in a sine wave shape with respect to time, data in which the position changes in a triangular wave shape or a sawtooth shape, and the like. Have been. Also, the period,
Standard values are also prepared as the amplitude data, and the operator determines four types of drive profile designation data to be used for measurement by combining the data (stored in the measurement sequence file). Keep). At this time, the operator determines the drive profile instruction data so that the moving speed of each reflector 14 at each time is always different (so that the time change patterns of the moving speeds of at least two reflectors 14 are not the same). I do. In addition,
In the computer, there are several standards that can be used as drive profile designation data and whose contents are set so that the fluctuation width of the reference light path length due to the movement of the reflector 14 is equal to or less than the coherent length of the short coherent long light. Data is prepared, and the operator usually creates a measurement sequence file by selecting data to be used from among those standard data.

Further, the operator sets a measurement condition comprising X and Y coordinates x and y of the measurement point, four Z coordinates z _a , z _b , z _c and z _d and measurement time designation data t. Data is set in the measurement sequence file as needed.
Here, the Z coordinate is a coordinate set in the depth direction of the measurement point, and the X and Y coordinates are orthogonal coordinates set on a plane perpendicular to the depth direction.

Then, when actually starting the measurement, the operator runs the measurement program. The computer 51 that has started the operation according to the measurement program first issues an initialization command to the scanning optical system 12 to set the state of the scanning optical system 12 to the reference state. That is, the computer 51 sets the position (X, Y) where the measurement light is introduced to be the reference position (x ₀ , y ₀ ).

Next, the computer 51 shifts to a state of waiting for an operator to input a measurement sequence file name. Then, when the measurement sequence file name is input, the four types of drive profile designation data stored in the designated measurement sequence file and the subsequent element data x _i , y _i , z in each measurement condition data _ai , z _bi ,
Read z _ci , z _di , and t _i (i = 1 to Nmax). Next, the computer 51 notifies the drive circuits in the reflector drive mechanisms 31a to 31d of the four types of drive profile designation data, respectively, and waits for an operation to instruct the start of measurement.

On the other hand, after running the measurement program, the operator inputs the name of the measurement sequence file to be used, and turns on the light source 16 to check the position to be irradiated with the measurement light. In the device, the subject)
By adjusting the position of the optical measuring device, the relative positional relationship between the sample 1 to be measured and the optical measuring device is
A predetermined positional relationship is taken. When the adjustment of the positional relationship is completed, the light source 16 is turned off, and the computer 51 is instructed to start measurement.

Computer 51 instructed to start measurement
Operates according to the flowchart shown in FIG. That is,
First, the computer 51 sets “1” to a variable i (step S101), and sets the light source 10 (light source for measurement) to
An operation start (start of generation of short coherent long light) is instructed (step S102). Further, the computer 51 displays a graph frame on the monitor 52 for illustrating the measurement result.

Next, the computer 51 instructs the scanning optical system 12 to change the measurement light introduction position to the position (x _i , y _i ) (step S103). further,
The computer 51 determines the center position of the reflectors 14a to 14d with respect to the reflector driving mechanisms 31a to 31d by the position z _ai.
To _di (step S10)
4).

As described above, in the present optical measuring apparatus, the reference light path length when each reflector is located at the reference position is different. Each reflector driving mechanism 31 is instructed to move from the position z _ai to z _di in a form taking into account the difference in the optical path length. More specifically, control information including data obtained by converting z _{ai to} z _di into data corresponding to the length from the reference position is supplied to each reflector driving mechanism. Although not shown in the flowchart, it is not necessary to change the position (x _i , y _i ), that is, x _i = x _i-1 and y _i
If = y _i−1 , the computer 51 ends step S103 without issuing an instruction to the scanning optical system 12 (proceeds to step S104). Similarly, position z
_xi (x = a to d) does not need to be changed (z _xi
= Z _xi-1 ), the computer 51 proceeds to step S104 without issuing an instruction to the reflector driving mechanism 31x.
To end.

After the end of step S104, the computer 51 waits for input of information indicating that the position change has been completed from the instructed device (step S10).
5) Do (if there is no device that has issued the instruction, end step S105 without waiting for information input).
When the notification is received from all the devices that have issued the instruction (step S105; Y), the computer 51
Represents the position data from the position sensors 50a to 50d as i
The data is acquired and stored as data relating to the third measurement (step S106). This process is performed to accurately recognize the position of each reflector 14, and the reflector driving mechanism 31 can move the reflector 14 to the position indicated by the computer 51. If
Step S106 can be omitted.

Next, the computer 51 instructs the drive circuits in the reflector drive mechanisms 31a to 31d to start a minute drive operation (drive control operation in accordance with drive profile instruction data) (step S107). And
The process of periodically acquiring data from the A / D converter 44 is started, and the acquired data is stored as the i-th measurement data (step S108). In this step, the computer 51 plots the measured data in the above-described graph frame on the monitor 52.

After performing such processing for the time t _i , the computer 51 instructs the reflector driving mechanisms 31a to 31d to stop the minute driving operation, and ends step S108. I do.

After the end of step S108, the computer 51 increments the content of the variable i by "1" (step S109), and if i≤Nmax (step S110; Y), the next measurement is performed. In order to perform the processing, the processing from step S103 is executed again. On the other hand, i>
If it is Nmax (step S110; N), the computer 51 instructs the measurement light source 10 and the like to stop the operation (step S111). And step S
A frequency analysis is performed on each of the measurement data acquired in step 108 in consideration of the contents of the drive profile designation data.
The optical characteristic data relating to × Nmax measurement points is calculated and stored (step S112), and the processing shown in the figure is terminated.
For example, if drive profile designating data in which the relationship between position and time is represented by a triangular wave is given to each of the reference device driving mechanisms 31a to 31d, the interference light incident on the photoelectric converter 40 will be described. Time change component S of intensity
(t) can be expressed by the following equation (1), assuming that there is no attenuation of the measuring light, fluctuation of the intensity of the light source, etc. in the sample to be measured.

[0057]

(Equation 1)

In the equation (1), R _i (t) is i
Th from the measurement point position (depth) is determined by the reference light optical path length, a reflected light intensity at time t, omega _i
Is the modulation angular frequency of the ith modulated interference light, φ
_i is the phase.

As described above, the photoelectric converter 40 adds the reflected light intensity R _i (t) at each measurement point to the sum of signals modulated at the angular frequency ω _i (i = 1 to n; in the embodiment, n = 4) Light having a considerable time-varying component is incident. Reflected light R
_i (t) can be regarded as a time-independent value R _i during a certain short measurement time, so that the power spectrum S
If the magnitudes of the modulation angular frequencies ω _{1 to} ω _n appearing in (ω) can be obtained separately (if ω ₁ to ω _n have different values), each reflected light intensity R Information correlated with _i can be obtained.

In the present optical measuring device, since the drive profile instruction data is determined so that the moving speed of each reflector 14 at each time is different, ω ₁ to ω _n (n = 4 in the embodiment) Have different values from each other. For this reason, the output of the A / D converter 44 includes the optical characteristic data relating to the four measurement points in a form that can be discriminated.
Optical characteristic data of four measurement points can be calculated from the i-th measurement data collected in 108.

When drive profile instruction data for changing the position of the reflector in a sinusoidal manner is given to each reflector drive mechanism, the output of the A / D converter includes an individual reflector (measurement). Point), a signal whose power spectrum is represented by the following equation (2) is included. For this reason, in step S112, the computer is programmed so that a routine for obtaining the magnitudes of the components such as the angular frequencies ω _r and 2ω _r for each measurement point by FFT or the like is executed. Incidentally, in the formula, J _n is n Bessel function, k is 2 [pi / lambda, L _a is the amplitude of the oscillating movement of a reflector (minute vibration), omega _r is the angular frequency of the minute vibration,
t _M is the measurement time.

[0062]

(Equation 2)

By the way, if 2 kL _{a is set} to an arbitrary value, a component having _a coefficient J ₀ (2 kL _a ), that is, a DC component which cannot be distinguished from noise increases, so that the reflector is vibrated in a sine wave shape. the time, to assume a J ₀ (2kL _a) is "0", by selecting 2kL _a, it is desirable to increase the relative strength of the other of the angular frequency of the signal. For example, as in the optical measuring device of the first embodiment, the wavelength λ is 830n as short coherent long light.
In the case of using light of m, the value of J ₀ (2kL _a) is 2kL _a becomes "0", since it is approximately 2.405, L _a is approximately 158.9nm (= 2.405 × λ / 4π), it is desirable to oscillate each reflector at a different cycle.

As described in detail above, by using the optical measuring device of the first embodiment, it is possible to simultaneously obtain optical characteristic data of four measuring points having different depths. For this reason,
The use of the optical measuring device according to the first embodiment makes it possible to complete the measurement in a shorter time than in a conventional optical measuring device.

The optical measuring apparatus of the first embodiment is configured using a reflector driving mechanism that receives various driving profile instruction data, but uses a reflector driving mechanism that can execute only a specific driving control. The optical measurement device may be configured by using the above. Further, the optical measuring device of the first embodiment is a device that uses the position sensor only for detecting the center position of the reflector. However, in step S108, the output of the position sensor is also periodically taken in. In step S112, the computer may be programmed so that a process using the data (so-called synchronous tuning detection process) is performed.

Naturally, a circuit for performing synchronous tuning detection using the output of the position sensor with respect to the output of the photoelectric converter is provided in all stages of the computer, and the optical output is input to the computer so that the output of the circuit is input to the computer. A measuring device may be configured.

Although the optical measuring apparatus of the first embodiment does not use a special medium as an optical path, all or a part of the optical path may be replaced with a single mode optical fiber, a polarization maintaining optical fiber, or the like. Naturally, it may be constituted by an optical fiber capable of preserving the polarization plane.

<Second Embodiment> An optical measurement device according to a second embodiment is a modification of the optical measurement device according to the first embodiment. The configuration of the signal processing circuit and the contents of the measurement program executed by the computer Are different devices. Also, the type of drive profile designation data that can be set in the measurement sequence file is smaller than the optical measurement device of the first embodiment.

The configuration and operation of each part of the optical measuring apparatus according to the second embodiment, except for the signal processing circuit and the computer, are exactly the same as those of the optical measuring apparatus according to the first embodiment. The description will be omitted, and the optical measurement device of the second embodiment will be described with reference to the configuration diagram of the signal processing circuit (FIG. 3).

As shown in FIG. 3, the signal processing circuit 41-2 provided in the optical measuring device of the second embodiment includes an amplifier 42
BPF43, rectifier 45, LPF
(Low-Pass Filter) 46, a logarithmic amplifier 47, and a circuit including an A / D converter 44 are provided.
The outputs of the / D converters 44a to 44d are supplied to a computer 51 (not shown). BPF43a-43
d is the angular frequency ω from the output of the amplifier 42, respectively.
The filter passes a signal of a narrow frequency component centered on a, ωb, ωc, ωd.

In the optical measuring apparatus according to the second embodiment, the contents of the drive profile designation data that can be set in the measurement sequence file are limited to those that generate the interference light component of the angular frequency. More specifically, the type of the drive profile designation data is limited to the one in which the reflector 14 is driven in a triangular wave or sawtooth shape, and the parameter that can be designated is limited to only the amplitude (for the period, refer to The movement speed of the mirror is automatically calculated from the amplitude so as to correspond to the angular frequency).

Therefore, the BP in the signal processing circuit 41-2 is
From F43a-43d, the reflectors 14a-1
An interference light component signal resulting from the reference light associated with 4d is output. The rectifiers 45a to 45d are respectively BPF4
3 a to 43 d rectify the AC signal output from the LPF 46.
a to 46d remove high frequency components (noise components) from the rectified signal. That is, the LPFs 46a to 46d
Output a DC signal at a level correlated with the reflected light intensity at the measurement points having different depths.

The logarithmic amplifiers 47a to 47d are respectively
The signals from the LPFs 46a to 46d are logarithmically amplified. That is, the logarithmic amplifiers 49a to 49d are connected to the LPFs 46a to
Adjust the dynamic range of the signal from 46d. A
/ D converters 44a to 44d are logarithmic amplifiers 49a to 49d.
The analog signal from d is converted into a digital signal and supplied to a computer.

As described above, the optical measuring apparatus according to the second embodiment includes, as a signal processing circuit, a circuit that outputs data directly correlated with the reflected light intensity at each measurement point. For this reason, a computer in the optical measurement apparatus stores a measurement program for collecting optical characteristic data without executing frequency analysis (processing equivalent to step S112).

With the optical measuring device of the second embodiment, the optical characteristic data of four measuring points having different depths can be obtained at the same time, so that the measurement can be completed in a shorter time than the conventional optical measuring device. Can be done. Further, the optical measurement device of the second embodiment has a computer with an arithmetic processing amount of:
Since the number of devices is smaller than that of the optical measuring device of the first embodiment, the device is operated at a high speed correspondingly.

<Third Embodiment> An optical measuring device according to a third embodiment is a modification of the optical measuring device according to the first embodiment. The optical measuring device according to the third embodiment is different from the optical measuring device according to the first embodiment in the configuration of the reference light modulator and the operation procedure of the computer. Has become. For this reason, only those descriptions will be given here.

FIG. 4 shows a configuration of a reference light modulator provided in the optical measuring device according to the third embodiment. As shown, the third
The basic configuration of the reference light modulation unit 30-3 of the embodiment is such that a member 32 and a moving mechanism 33 are added to the reference light modulation unit 30 of the first embodiment. On one surface of the member 32, a moving mechanism 33 is fixed, and on the other surface,
The reflector drive mechanisms 31a ^{* to} 31d ^* are fixed. The position sensors 50a to 50d are fixed to the housing of the optical measurement device (to the moving mechanism 30).

The moving mechanism 33 is a mechanism for moving the member 32 in the vertical direction in the figure, and operates by receiving control information from a computer. Reflector drive mechanism 31a ^* -3
1d ^* has almost the same configuration as the reflector driving mechanism 31 in the optical measuring device of the first embodiment. However, the reflector driving mechanisms 31a ^{* to} 31d ^* are responsible for only the minute driving operation of the reflectors 14a to 14d, and the change of the depth of the measurement point is as follows.
This is performed by the moving mechanism 33. That is, the reference light modulation mechanism 30-3 is configured to operate the reflector 14x (x = a to x) when the reflector driving mechanisms 31a ^{* to} 31d ^* do not function.
The configuration is such that the Z coordinate z _x of the measurement point corresponding to the optical path length of the reference light related to d) can be calculated from the Z coordinate of the other reflector 14y (y ≠ x).

For this reason, the measurement used in the present optical measurement device
The fixed sequence file specifies four drive profiles
Data, X and Y coordinates x and y of the measurement point, and one Z coordinate
Measurement condition composed of mark z and measurement time designation data t
It is a file in which case data is set. Soshi
Then, the computer in the present optical measurement device executes step S1.
In the step corresponding to 04, the moving mechanism 33
Position z_iTo move to. As a result, each reflector 14
a to 14d respectively indicate that the Z coordinate of the measurement point is z _i+ △
z_a, Z_i+ △ z_b, Z_i+ △ z_c, Z_i+ △ z_d(△ z_a, △
z_b, △ z_c, △ z_dIs a constant corresponding to the optical path difference between the reference beams.
Number, and the structure of the reference light modulation mechanism 30-3).
Is moved to a new position. After that, the computer
Exactly the same as the computer 51 in the optical measuring device of the embodiment
Perform processing.

The optical measuring device of the third embodiment having such a configuration is different from the optical measuring device of the first embodiment.
Although the degree of freedom in selecting measurement points to be measured at the same time is reduced, data on a plurality of measurement points can be measured simultaneously. Therefore, the use of the optical measuring device according to the third embodiment makes it possible to complete the required data measurement in a short time. Also, the reflector driving mechanisms 31a ^{* to} 31
As d ^* , it is possible to use a mechanism in which the movable range of the reflector is narrow. Therefore, the optical measurement device according to the third embodiment includes:
It is also a device that can be manufactured at low cost.

<Fourth Embodiment> An optical measuring device according to a fourth embodiment is a modification of the optical measuring device according to the first embodiment, and differs from the optical measuring device according to the first embodiment in the configuration of the reference light modulation mechanism and the operation procedure of the computer. Has become.

FIG. 5 shows the configuration of a reference light modulation mechanism provided in the optical measuring device according to the fourth embodiment. As illustrated, the reference light modulation mechanism 30-4 of the fourth embodiment includes a reflector 14a
^# 14 d ^# , the fixed member 34 having the rotating shaft 54, the reflector driving mechanism 31 ^# , and the position sensor 50 ^# . Reflector 1
4a ^# ~14d ^# is called a cylindrical mirror, respectively, when the fixing member 34 is at the reference position, the separation reference light from the corresponding lens system 13a~13d is, to be incident on the center, stationary member 34. Each of the reflectors 14a ^{# to} 14d ^# has a radius of curvature corresponding to a distance from (the center of) the rotation axis 54. That is, each reflector has a mode in which the incident light can be returned in the same direction as the incident direction even when the rotation of the fixed member 34 about the rotation axis 54 occurs.

The reflector drive mechanism 31 ^# is connected to the rotation shaft 54 of the fixed member 34, and swings the fixed member 34 according to the given drive profile instruction data. That is, in the optical measuring device of the fourth embodiment, the rotation shaft 54
With the rotation of, the optical path length of each reference light changes at a speed corresponding to the ratio of the distance between the rotation axis 54 and each reflector 14 ^# . Position sensor 50 ^# is also connected to the rotary shaft 54, the position sensor 50 ^# outputs data indicating a rotation angle from a reference position of the rotary shaft 54 (the posture of the fixing member 34).

On the other hand, a computer (not shown)
Data related to the distance of the reflectors 14a ^{# to} 14d ^# from the rotation axis 54, data indicating the correspondence between the output of the position sensor 50 ^# and the actual position (posture) of the fixed member 34, and the like are stored (set). I have. When the computer executes the measurement sequence file creation program, the computer specifies one drive profile designation data (consisting of a rotation angle range Δθ and time change pattern data defining a time change pattern of angular velocity) and the X and Y coordinates x of the measurement point. , Y, one Z coordinate z, and measurement condition data including measurement time designation data t, are created.

Then, the computer in the optical measuring apparatus
Is executed when the control according to the measurement program is executed.
In a step corresponding to 104, the reflector driving mechanism 31^#
For the reflector 14d^#The measurement point related to_iTo
Give instructions to move. As a result, the other reflector 1
4a^#~ 14c^#Means that the Z coordinate of the measurement point is z _i
+ Δz_a(θ), z_i+ Δz_b(θ), z_i+ Δz_c(θ)
Moved to the position (in the optical measuring device of the fourth embodiment,
Unlike the optical measuring device of the third embodiment, the difference in the optical path length
Is a function of the angle θ of the rotating shaft 54). After that,
The computer is a computer in the optical measuring device of the first embodiment.
The operation is similar to that of the data 51. Ie computer
Is a reflector driving mechanism 31^#To start
Instruct the beginning. Reflector instructed to start small fluctuation operation
Drive mechanism 31^#Is the drive profile finger
According to the constant data, centered on the angle θ at that time
The computer rotates within the angle range of ± Δθ / 2,
Signal from the signal processing circuit
Get more data.

[0086] Even if the optical measuring device of the fourth embodiment is used, data on a plurality of measurement points can be measured at the same time. Therefore, similar to the optical measuring devices of the first to third embodiments,
The required data measurement can be completed in a short time. Further, when forming the optical measuring device of the fourth embodiment, only one reflector driving mechanism needs to be prepared, so that the optical measuring device of the fourth embodiment has the first to third optical measuring devices.
It is also an apparatus that can be manufactured at lower cost than the optical measurement apparatus of the embodiment.

<Fifth Embodiment> Similarly to the optical measurement device according to the fourth embodiment, the optical measurement device according to the fifth embodiment is different from the optical measurement device according to the first embodiment in the configuration of the reference light modulation mechanism,
The operation procedure of the computer is different.

FIG. 6 shows a schematic configuration of a reference light modulation mechanism provided in the optical measuring device of the fifth embodiment. As shown, the optical measuring device of the fifth embodiment has two reflector driving mechanisms 31L and 31R and four reflectors 14a ^+.
To 14d ⁺ , the position sensors 50a to 50d, and the member 35
_{L, 36R, 36 1, 36} 2 reference light modulating mechanism 30-5 constituted by is provided.

The reflector driving mechanisms 31L and 31R have the same function as the reflector driving mechanism 31 provided in the optical measuring device of the first embodiment. That is, the reflector drive mechanisms 31L and 31R move the members 35L and 35R to the positions specified by the computer, respectively.
When the start of the change is instructed, the members 35L, 35L are driven in accordance with the drive profile designation data given thereto.
The positions of the members 35L and 35R are controlled so that R slightly fluctuates around the current position.

[0090] In portions where the circle is shown in the figure, members 35L, 35R or the reflectors 14a ⁺ ~14d ⁺ (is attached member) mounted rotatably relative to the member 36 _1, 36 ₂ Have been. Therefore, the reflector 14a
^{+ ~14d +} posture, members 35L, 35R whatever be moved to position (member 36 _1, 36 be varied _second angle), always be controlled to be constant. That is, the reference light modulating mechanism 30-5, the member 36 _1, 36 ₂ What attitude take the light from the lens system 13a~13d is reflected by the reflector 14a ⁺ ~14d ^+, the lens system 13a ~ 13
d.

A computer (not shown) stores (sets) data and the like relating to the mounting positions of the reflectors 14a ^{+ to} 14d ⁺ . When the computer performs an operation in accordance with the measurement sequence file creation program, the computer sets two drive profile designation data and the X of the measurement point.
Then, a measurement sequence file is created that stores measurement condition data including Y coordinates x and y, two Z coordinates z ₁ and z ₂ , and measurement time designation data t.

When the computer in the optical measuring apparatus executes control according to the measurement program, the computer executes step S
In a step corresponding to 104 (FIG. 2), an instruction is issued to the reflector driving mechanism 31R to move the measurement point related to the reflector 14a ⁺ to the position z _1i, and to the reflector driving mechanism 31L, An instruction is issued to move the measurement point related to the reflector 14d ⁺ to the position _z2i . After that, the computer performs the same processing as the computer 51 in the optical measurement device of the first embodiment, and acquires measurement data for four measurement points.

Even when the optical measuring device of the fifth embodiment is used, data on a plurality of measuring points can be measured simultaneously, so that the optical measuring device of the fifth to fifth embodiments requires a short time. The measurement of the data to be completed can be completed.

<Sixth Embodiment> An optical measuring device according to a sixth embodiment is a modification of the optical measuring device according to the fourth embodiment. The configuration and the operation procedure of the computer are different from each other.

FIG. 7 shows a configuration of a reference light modulator provided in the optical measuring device according to the sixth embodiment. As shown,
The reference light modulation unit 30-6 of the sixth embodiment includes a reflector 14
a ″ to 14d ″, reflector drive mechanism 31 ″, position sensor 5
0 ". The reflectors 14a" to 14d "include:
A plate-shaped member having a rotation center and a mirror surface on the side surface, and having a shape in which the distance from the rotation center to the side surface changes according to the rotation angle, is used. Specifically, as illustrated in the figure, the reflector 14d ″ has a rotation angle θ.
The distance Ld (θ) to the side surface at the position (unit: radian; 0 ≦ θ ≦ 2π) is constituted by a member represented by Ld ₀ + ΔLd · θ / 2π (so-called Archimedes curve). The reflectors 14a ″ to 14c ″ are Ld
₀ , ΔLd, corresponding lengths La ₀ , ΔLa, Lb ₀ , ΔL
b, Lc ₀ , and ΔLb are made of members different from other reflector constituent members.

The rotation shaft of the reflector driving mechanism 31 "is connected to the center of rotation of the reflectors 14b" to 14d ".
The position sensor 50 ″ is also connected to the rotation axis of the fixed member 53, and outputs data indicating the rotation angle of the rotation axis from the reference position.

The reflector drive mechanism 31 ″ is controlled by a computer in the same manner as the reflector drive circuit 31 ^{# of} the fourth embodiment. That is, the reflector drive mechanism 31 ″ has a rotation angle as drive profile designation data. The range Δθ and the time change pattern data of the angular velocity are given. And
The reflector driving mechanism 31 ″ rotates the group of reflectors when the movement to the z position is instructed, so that the lens system 13
Aside, the side surface represented by θ ₀ corresponding to the z is turned.
Thereafter, when the start of the minute fluctuation operation is instructed, the rotation angle changes at the angular velocity specified by the time change pattern data, and the side of the range represented by θ ₀ −Δθ / 2 to θ ₀ + Δθ / 2. The rotation axis is controlled so that is directed to the lens system 13 side.

A computer (not shown) stores (sets) the shape data (L ₀ , ΔL, etc.) of the reflectors 14 a ″ to 14 d ″, and the computer stores the data and the position sensor 50 ″. Using the data output from the A / D converter and the data output from the A / D converter, Lx ₀ + ΔLx · θ ₀ /
Optical characteristic data at four measurement points whose depth is determined by the value of 2π (x = a to d) is calculated.

Even if the optical measuring device of the sixth embodiment is used, data on a plurality of measuring points can be measured simultaneously, and therefore, like the optical measuring devices of the other embodiments,
The required data measurement can be completed in a short time.

In this embodiment, the reflector driving mechanism 3
Although a mechanism for repetitively moving the reflector group within a fixed angle range is used as 1 ", a mechanism for rotating the reflector group may be used. From the data output from the position sensor 50 ″,
Since the information for discriminating the optical path length of each reference light and the signal related to each reference light can be obtained,
Optical characteristic data for four measurement points having different depths can be calculated in parallel. Further, the shape of each reflector is not limited to the shape shown in FIG. 7, and the computer uses the data (data equivalent to θ) provided from the position sensor 50 ″ to form each reflector formed at that time. Any shape can be used as long as the optical path length of the reference light can be recognized and the signal related to each reference light can be discriminated from the data output by the A / D converter.

<Seventh Embodiment> FIG. 8 shows a configuration of an optical measuring apparatus according to a seventh embodiment. The components of the optical measuring device according to the seventh embodiment except for the reference light modulating unit 30-7 employ a polarization maintaining optical fiber in each optical path of the optical measuring device according to the first embodiment. For this reason, in the optical measurement device of the seventh embodiment, a half mirror is used (intensity split type).
Instead of the optical multiplexer 18 and the optical multiplexer / demultiplexer 11, a distributed coupling type optical multiplexer 17 'and an optical multiplexer / demultiplexer 11' are used.

As shown in the figure, the reference light modulation mechanism 30-7 in the present optical measuring apparatus includes an optical demultiplexer 18, modulation mechanisms 38a to 38d, and optical fibers 25 having different lengths.
a ′ to 25d ′, and an optical multiplexer 19. Optical splitter 1
8 separates the reference light input through the optical fiber optical path 23 ₁ ′ into four lights, and
d '. Each of the modulation mechanisms 38a to 38d is composed of a columnar piezo element (PZT) and its driving circuit, and each of the modulation mechanisms 38a to 38d (piezo element) has a part of the optical fiber 25a 'to 25d'. It is wound. The other ends of the optical fibers 25a 'to 25d'
The optical multiplexer 19 is connected to the optical multiplexer 19, and multiplexes the light from the optical fibers 25a 'to 25d' and supplies the multiplexed light to the optical multiplexer / demultiplexer 11 'via the optical fiber optical path 23'. That is, in this optical measuring device, the optical fibers 25a 'to
A reference light modulation mechanism 30-7 that modulates reference light propagating inside by applying an external force to 25d 'is used. Modulation mechanism 38 by computer 51
The control procedure of a to 38d is as follows. The computer 51 in the optical measuring device of the first embodiment is operated by the reflector driving mechanisms 31a to 31d
Is basically the same as the one performed for, so the description is omitted.

Even if the optical measuring device according to the seventh embodiment is used, data on a plurality of measuring points can be measured simultaneously. Therefore, similar to the optical measuring devices according to the other embodiments,
The required data measurement can be completed in a short time. Further, the optical measuring device of the seventh embodiment uses an optical fiber, so that the device can be easily miniaturized.

Although the present optical measuring device is configured using the polarization maintaining optical fiber, it is obvious that a single mode optical fiber may be used. However, single-mode optical fibers are inferior in polarization stability to polarization-maintaining optical fibers.Therefore, when single-mode optical fibers are used, devices that are susceptible to disturbances and temperature changes are formed. Would. Therefore, it is desirable to use a polarization-maintaining optical fiber when configuring an optical measurement device using an optical fiber.

<Eighth Embodiment> FIG. 9 shows a configuration of an optical measuring apparatus according to an eighth embodiment. As illustrated, the optical measurement device according to the eighth embodiment includes four light sources 10a to 10d. The light sources 10a to 10d have different wavelengths λa to
It is a light source that generates short coherent long light of λd.

The first light source 10x (x = a to d) emits the short coherent long light on the optical path 21x, and the first light
An optical multiplexer / demultiplexer 11x, which is the same optical circuit as the optical multiplexer / demultiplexer 11 used in the embodiment, is provided. Then, on the measurement light output side (on the optical path 22x) of the optical multiplexer / demultiplexer 11x,
A wavelength division multiplexer / demultiplexer 55 is provided.

The wavelength multiplexing / demultiplexing device 55 is an optical multiplexer / demultiplexer.
The light obtained by combining the short coherent lengths of the wavelengths λa to λd from 1a to 11d is emitted toward the scanning optical system 12, and the light incident from the scanning optical system 12 is emitted to the optical path 22 corresponding to the wavelength. Optical circuit. That is, the wavelength division multiplexing / demultiplexing device 55 emits the light of the wavelength λa out of the light incident from the sample to be measured on the optical path 22a and the light of the wavelength λb on the optical path 22b. Then, the light having the wavelength λc is emitted onto the optical path 22c, and the light having the wavelength λd is emitted onto the optical path 22d.

The optical paths 24a to 24d of the optical multiplexer / demultiplexers 11a to 11d
Lens systems 13a to 13d are provided on the 24d side, and reflectors 14a to 14d fixed to the member 32 are provided at positions where reference light is incident through the lens systems 13a to 13d.
And a reference light modulation mechanism 30-8 including a reflector drive mechanism 31 for driving the reflectors 14a to 14d (the member 32) and a position sensor 50. Also, the optical multiplexer / demultiplexer 11
Optical multiplexers 56 are provided on the optical paths 23a to 23d side of
Is provided, and the optical multiplexer 56 is an optical multiplexer / demultiplexer 11a.
The light obtained by multiplexing the interference lights from １１11d is supplied to the photoelectric converter 40.

As described above, in the optical measuring device according to the eighth embodiment, the reflectors 14a to 14d
1 are driven at the same speed, but the reference light incident on each reflector has different wavelengths. That is, the moving speed of the reflector is the same, but the modulation pattern applied to the reference light is different. Therefore, the output of the photoelectric converter 40 includes
Similar to the optical measuring device of each embodiment, the signal includes a signal in a form that can distinguish the magnitude of the reflected light component from four measurement points having different depths.
4 is processed by the same procedure as the computer 51 in the optical measuring device of the first embodiment,
The optical characteristic data on the measurement point is acquired at the same time.

Note that, without providing the optical multiplexer 56, four photoelectric converters are provided for the light output from each of the optical multiplexers / demultiplexers 11a to 11d, and an amplifier, a BPF, a rectifier , An LPF, a logarithmic amplifier or an amplifier, and a circuit including an A / D converter (a circuit used in the signal processing circuit of the second embodiment), and the output of each A / D converter is supplied to a computer. Of course, the optical measuring device may be configured to be supplied.

<Modifications> Various modifications can be made to the optical measuring device of each embodiment. For example, the optical measurement devices according to the third to eighth embodiments may be configured using the signal processing circuit used in the optical measurement device according to the second embodiment.

A reflector 1 composed of a total reflection mirror
Instead of 4, a corner cube, a cat's eye, or the like can be used. Further, in the optical measurement device of each embodiment, the SLD is used as the light source 10, but any light source can be used as long as it can generate light having a short coherent length as a result. For example, light emitting diodes (LEDs), pulsed laser light sources, incandescent light sources, continuous wave lasers with poor coherence, lasers oscillated with currents that do not exceed a threshold current, light sources combining multiple multimode lasers, lasers An excitation fluorescent light source or the like can be used. In addition, a light source that generates short coherent long light can be used, which is configured by adding a device that randomly modulates the output light of the coherent light source such as a laser and generates an irregular jump in phase. .

In the optical measuring apparatus and the like according to the fourth embodiment, the reference light path length is changed (movement of the measuring point) and the reference light is modulated using the same mechanism. An optical measurement device may be configured by separately providing a mechanism for moving the optical measurement device. That is, the moving mechanism used in the optical measuring device according to the third embodiment may be added to the optical measuring device according to the fourth embodiment. Also, in a part of the optical path of each reference light,
A device may be provided such that a reference light optical fiber pair whose end faces are opposed to each other is provided, and the optical path length of the reference light is changed by adjusting the interval between the end faces of the reference light fiber pair. By slightly changing the frequency, the reference light may be frequency-modulated. Further, a mechanism for changing the optical path length may be provided on the measurement light side instead of the reference light side.

Further, a mechanism for modulating the reference light is as follows.
The present invention is not limited to those described in the respective embodiments. For example, a mechanism using an acousto-optic element may be employed. Further, an optical medium having a refractive index distribution is separately arranged on the optical path of each reference light (or one optical medium is arranged so as to cross all the optical paths), and these (or the same) are arranged. By changing the relative position of the optical medium with respect to the optical path of the reference light, the reference light can be modulated in different patterns.

The optical measuring device may be configured so that not only frequency modulation but also amplitude modulation is performed on the reference light, and the optical measuring device may be configured so that only amplitude modulation is performed. Is also good. Further, by providing a polarization plane rotator by a magnetic field such as a Faraday element in each reference optical path, the apparatus may be configured such that each reference light is modulated in the form of rotation (modulation) of the polarization plane.

The apparatus may be configured so that not only the modulation of the reference light but also the modulation of the measurement light is performed. For example, an amplitude modulation element or the like is further provided on the measurement optical path side so that amplitude modulation is performed on the measurement light, and information on a plurality of measurement points is obtained as a result of frequency modulation on each reference light and amplitude modulation on the measurement light. The device can also be configured such that the light contained in the optical multiplexer / demultiplexer can be emitted from the optical multiplexer / demultiplexer.

Although the optical measuring apparatus of each embodiment is an apparatus capable of performing simultaneous measurement of four measuring points, the apparatus may be configured such that simultaneous measuring of a plurality of measuring points other than four measuring points can be performed. That is natural.

The optical measuring device of each embodiment is a device that is controlled so that the amount of change in the optical path length of the reference light at the time of measurement is equal to or less than the coherent length of the short coherent long light output from the light source. However, similarly to the conventional optical measurement device, the device may be configured such that the wavelength of the reference light is shifted with the movement of the measurement point by changing the optical path length of the reference light in a predetermined pattern. Is natural. However, when the device is configured in this manner, a device having a lower degree of freedom in measurement (a restriction is imposed on the measurement order and the like) as compared with the optical measurement device of each embodiment is formed.

[0119]

According to the optical measuring apparatus of the present invention, a plurality of measuring points having different depths can be measured at the same time, so that the desired information can be collected in a shorter time than the conventional optical measuring apparatus. I can do it. As a result, by using the present optical measurement device, it is possible to accurately measure a sample such as a biological sample, which is difficult to maintain a fixed posture.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical measurement device according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation procedure of a computer included in the optical measurement device according to the first embodiment.

FIG. 3 is a configuration diagram of a signal processing circuit provided in an optical measurement device according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a reference light modulation mechanism included in an optical measurement device according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of a reference light modulation mechanism included in an optical measurement device according to a fourth embodiment of the present invention.

FIG. 6 is a configuration diagram of a reference light modulation mechanism included in an optical measurement device according to a fifth embodiment of the present invention.

FIG. 7 is a configuration diagram of a reference light modulation mechanism included in an optical measurement device according to a sixth embodiment of the present invention.

FIG. 8 is a configuration diagram of an optical measurement device according to a seventh embodiment of the present invention.

FIG. 9 is a configuration diagram of an optical measurement device according to an eighth embodiment of the present invention.

[Explanation of symbols]

 10, 16 light source 11, 15 optical multiplexer / demultiplexer 12 scanning optical system 13 lens system 14 reflector 17 total reflection mirror 18, 56 optical multiplexer 30 reference light modulation mechanism 31 reflector driving mechanism 32 member 33 moving mechanism 40 photoelectric converter 41 signal processing circuit 42 amplifier 43 BPF 44 A / D converter 45 rectifier 46 LPF 47 logarithmic amplifier 49 printer 50 position sensor 51 computer 52 monitor 55 wavelength multiplexing / demultiplexing device

Claims (17)

[Claims] An optical multiplexing means for multiplexing incident light; a light generating means for generating light having a short coherent length; a light generated by the light generating means; A light separating unit that separates the first to Nth reference lights from the first to Nth reference lights. The first to Nth reference lights separated by the light separating unit are modulated. A reference light introducing means for introducing the N reference light into the optical multiplexing means, and introducing the measurement light separated by the light separating means into the measurement sample, and combining the measurement light reflected and scattered by the measurement sample with the optical multiplexing. Measuring light introducing means for introducing the light into the means; photoelectric conversion means for outputting an electric signal at a level corresponding to the intensity of the light multiplexed by the optical multiplexing means; Modulation pattern applied to light From the electric signal output by the photoelectric conversion means, the optical path length from the light separation means to the optical multiplexing means of the first to N-th reference lights in the sample to be measured at that time. Calculating means for calculating optical characteristic data relating to the first to N-th measurement points located at positions corresponding to the above. 2. The first to N-th reflectors provided at positions where the first to N-th reference lights separated by the light separating means are incident, wherein the first to N-th reflectors are provided, respectively. The first to N-th light reflected by the N-th reflector
Introducing means for introducing a reference light into the optical multiplexing means, and reflector position control for controlling the positions of the first to Nth reflectors to perform modulation of different patterns on the first to Nth reference lights. 2. The optical measuring device according to claim 1, further comprising means. 3. The first to N-th reflectors each have a rotation axis on which a reference light is incident on a side surface, and each of the first to N-th reflectors is arranged from a center of the rotation axis on the side surface on which the reference light is incident. A reflector whose shape changes in accordance with the rotation angle of the rotation axis, and wherein the reflector position control means controls the rotation angle of the rotation axis of each reflector. The optical measuring device as described in the above. 4. The first to N-th reflectors are fixed to the same rotation axis and receive the reference light on the side surface, and each of the first to N-th reflectors rotates the side surface on which the reference light is incident. A reflector having a shape in which the distance from the center of the axis changes in accordance with the rotation angle of the rotation axis and at a rate different from the rate of change in the distance of the other reflector; The optical measuring device according to claim 2, wherein the means controls a rotation angle of the rotation shaft. 5. The first to N-th reflectors are mounted on a fixed member having a rotation axis so that the distances from the rotation axis are different from each other. 1st to Nth reflected by the vessel
Introducing means for introducing reference light into the optical multiplexing means, and reflector position control means for controlling the rotation angle of the rotation axis to perform modulation of patterns different from each other on the first to Nth reference lights. The optical measurement device according to claim 1, wherein: 6. The optical measuring device according to claim 5, wherein each of the first to N-th reflectors is a cylindrical mirror. 7. The first to N-th reflectors are rotatably attached to the fixed member, and the reflector position control means controls the position of the fixed member and the first to N-th reflectors. The reflecting surface of the N-th reflector is
The first member is oriented in a direction corresponding to the inclination of the fixing member.
6. The optical measuring device according to claim 5, wherein an angle of the N-th reflector with respect to the fixed member is controlled. 8. The first to N-th electrostrictive elements for introducing the first to N-th reference lights separated by the light splitting means to the optical multiplexing means, respectively. First to N-th parts around which
An optical fiber; and electrostrictive element control means for controlling the first to N-th electrostrictive elements such that different modulations are performed on the first to N-th reference lights. The optical measurement device according to claim 1. 9. The optical measuring apparatus according to claim 1, wherein said reference light introducing means includes an acousto-optic element for modulating the reference light. 10. The reference light introducing means includes: an optical medium having a refractive index distribution provided on an optical path of the first to N-th reference lights; and an optical medium of the first to N-th reference lights of the optical medium. 2. The optical measuring apparatus according to claim 1, further comprising: an optical medium position control unit that modulates the first to Nth reference lights in different patterns by changing a relative position with respect to an optical path. 11. An optical multiplexing device for multiplexing incident light, a light generating device having a short coherent length and generating first to N-th lights having different wavelengths, and a light generating device comprising: Light separating means for generating the first to N-th reference light and the first to N-th measuring light by separating the generated first to N-th light into reference light and measuring light, respectively; The first to N-th reference lights generated by the method are modulated and then introduced into the optical multiplexing means. The first to N-th measurement lights separated by the light separating means are used as the measurement target specimen. A measuring light introducing means for introducing the first to Nth measuring lights reflected and scattered by the sample to be measured to the optical multiplexing means, and an intensity of the light multiplexed by the optical multiplexing means. An electric signal of a corresponding level Photoelectric conversion means, and the reference light introducing means uses a modulation pattern applied to the first to Nth reference lights, and information on the wavelength of the first to Nth reference lights. From the electric signal to be output, the first to N-th reference lights in the sample to be measured are present at positions corresponding to the optical path lengths from the light separation unit to the optical multiplexing unit of the first to N-th reference lights at that time. Calculating means for calculating optical characteristic data relating to the N-th measurement point. 12. The reference light introducing means, when an electric signal for calculating optical characteristic data is acquired by the calculating means, from the light separating means for the first to Nth reference lights to the optical multiplexing means. Wherein the variation widths of the first to N-th reference optical path lengths, which are the optical path lengths up to, respectively, are maintained at about the coherent length of the light generated by the light generating means or less. The optical measuring device according to claim 1. 13. The optical measuring apparatus according to claim 12, further comprising a reference light path length changing unit for changing the first to Nth reference light path lengths. 14. The reference light introducing means performs a sinusoidal frequency modulation whose amplitude is set such that a DC component included in an electric signal output by the photoelectric conversion means is “0”, 14. The optical measuring apparatus according to claim 12, wherein the optical measuring apparatus is applied to the Nth reference light. 15. A detecting means for detecting a modulation pattern given to each reference light by the reference light introducing means, wherein the calculating means detects an electric signal output by the photoelectric conversion means and a detection of the detecting means. 15. The optical measurement apparatus according to claim 1, wherein the optical characteristic data relating to the first to Nth measurement points is calculated using the result. 16. A measuring light introducing position changing unit for changing an introducing position of the measuring light by the measuring light introducing unit into the measurement target sample, and introducing position information which is information indicating the introducing position is used. Storage means for storing in a form in which the measurement light introduction position changing means is controlled based on the position information stored in the storage means. 16. The optical measuring device according to claim 1, wherein optical characteristic data is calculated for each measurement point in which the position information is stored. 17. The storage means stores the introduction position information and the measurement time information in a form in which the order of use is understood. The calculation means calculates the introduction position information and the measurement time information for each measurement point in which the introduction position information is stored in the storage means. 17. The optical device according to claim 16, wherein the optical characteristic data is calculated using the electric signal output by the photoelectric conversion unit during a time corresponding to the measurement time information associated with the measurement point. measuring device.