JPH09145476A - Spectrometric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an accurate measured value while shortening measuring time when an average measured value of the whole measuring object sample or a partial wide area is obtained. SOLUTION: At measuring time of two-dimensional spectral diffraction, a motor driving circuit 5 drives a pulse motor 4 in synchronism with time necessary to obtain an image of a single frame, and a photometric unit 10 is continuously moved in the X axis direction thereby. Since the photometric unit 10 scans a wide area when a CCD image sensor 17 accumulates electric charge equivalent to a single frame, average spectrometry of this area can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectroscopic measurement device for measuring a spectral intensity distribution in a two-dimensional area on a sample.

[0002]

2. Description of the Related Art FIG. 6 is a configuration diagram of a main part centering on an optical system of a spectroscopic measurement device for performing spectroscopic measurement of a one-dimensional region of a sample. The light emitted from the light source 11 is the sample table 1
The light is reflected by a one-dimensional region extending in the Y-axis direction of the sample 2 placed on and is guided to the slit 12. The light that has passed through the slit 12 is collimated by the lens 13 and
The secondary light removal filter 15 and the lens 16 after being separated by
Is projected onto the photodetector 17 via. The photodetector 17 has a large number of minute light receiving elements arranged two-dimensionally,
Position information in the one-dimensional area of the sample 2 in the y-axis direction is
Information on the wavelength spread at each position in the one-dimensional region of the sample 2 is obtained in the λ-axis direction orthogonal to the y-axis direction. That is, a spectral image showing the spectral intensity distribution corresponding to the one-dimensional area on the sample 2 is obtained on the photodetector 17.

When the spectroscopic measurement of the two-dimensional area on the sample 2 is performed, the entire photometric unit 10 including the light source 11 and the like can be moved in the X-axis direction by a motor or the like, and the movement is stopped to move the one-dimensional area. After measuring the spectral image, the photometric unit 10 is moved to a position adjacent to the preceding one-dimensional region, and the spectral image of the next one-dimensional region is measured. As described above, the spectroscopic intensity distribution in the two-dimensional region is obtained by repeating the spectroscopic measurement in the one-dimensional region while moving the photometric unit 10 relative to the sample 2 intermittently. Of course, the same spectroscopic measurement can be performed even if the photometric unit 10 is fixed and the sample stage 1 is movable in the X-axis direction.

[0004]

In such a two-dimensional spectroscopic measuring apparatus, the main purpose is to accurately obtain the spectral characteristics of each local region, and therefore a high resolution is usually required. Therefore, the mechanism for the movement is designed so that the movement amount of the photometric unit 10 per movement becomes small. For this reason, for example, when it is desired to measure the average value (average reflectance, average transmittance, etc.) of the entire surface of the sample to be measured, the measurement value for each local region on the sample 2 is obtained, and then the averaging calculation process is performed. Will be done. Therefore, even when the purpose is to obtain an average measurement value of the entire sample surface to be measured or a wide area from the beginning (that is, when the resolution of the position on the sample 2 may be low), the entire sample 2 is first measured. Since it is necessary to perform precise spectroscopic measurement, there is a problem that the measurement time is long.

In order to solve this problem, a method of partially measuring the sample and replacing it with the average measured value of the entire sample is conceivable. Has the drawback that it cannot be obtained.

The present invention has been made to solve the above-mentioned problems, and its purpose is to reduce the measurement time when it is desired to obtain an average measured value of a wide area of the entire sample or a part of the sample to be measured. An object of the present invention is to provide a spectroscopic measurement device that can obtain an accurate measurement value while shortening it.

[0007]

Means for Solving the Problems The present invention, which has been made to solve the above-mentioned problems, provides a spectroscopic measurement device for spectroscopically measuring a two-dimensional region on a sample. Light source means for irradiating, b) a plurality of minute light receiving elements are arranged two-dimensionally, and the light detecting means for obtaining a light receiving signal by accumulating charges according to the light receiving energy, c) A spectroscopic means for projecting a one-dimensional region image of the sample in one dimension of the photodetection means and dispersing light in the other dimension, and d) the light source means, the photodetection means and the spectroscopic means. And a moving means for continuously moving either the photometric unit or the sample table on which the sample is placed in order to relatively move the photometric unit and the sample in a direction orthogonal to the one-dimensional region of the sample. , E) The moving hand according to the desired resolution To vary the speed of movement of, is characterized in that it comprises a driving means for generating a driving signal synchronized with a cycle for obtaining an image signal for one frame in said light detecting means.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The photo-detecting means in the spectroscopic measurement device according to the present invention uses, for example, a CCD image sensor as a sensor for accumulating electric charge according to received light energy. The CCD image sensor accumulates the received light energy as an electric charge within one frame period required for photometry of one frame of a two-dimensional image, and then transfers the accumulated electric charge signal. Since this signal transfer is performed within an extremely short time, most of one frame period is devoted to the charge storage time. Therefore, when the photometric unit and the sample stage are continuously moved relative to each other by the moving means, an average spectroscopic measurement of the entire region on the sample surface moved during one frame period is performed.

In order to associate the spectral image of one frame with the region on the sample from which the spectral image is obtained, in other words, in order to accurately reflect the measurement of the desired region in the spectral image of one frame, The driving means generates a driving signal for driving the moving means in synchronization with one frame period. That is, for example, when a pulse motor whose rotation angle is determined according to the number of drive pulse signals is used as the moving means, a predetermined number of drive pulse signals corresponding to the moving speed corresponding to the resolution are generated within one frame period. Generated to complete.

[0010]

Therefore, according to the present invention, the measurement time can be shortened according to the roughness of the resolution. For this reason,
For example, when measuring the average measurement value of each of a large number of samples to be measured, it is possible to measure each sample in a short time and measure a plurality of samples one after another.

[0011]

Embodiments of the spectroscopic measurement apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a main part of a spectroscopic measurement device according to the present invention. The linear drive guide rail 3 is attached to the photometric unit 10, and the photometric unit 10 is moved in the X-axis direction by the rotation of the pulse motor 4. The clock generation circuit 6 is the CCD image sensor 1
7, a necessary signal such as a frame synchronization signal (hereinafter referred to as “FSY signal”) indicating one frame period is supplied, and a necessary signal is also supplied to the motor drive circuit 5 that drives the pulse motor 4.

FIG. 2 shows an example of the circuit configuration of the motor drive circuit 5. A high-speed master clock signal (hereinafter referred to as “MCK signal”) and an FSY signal indicating the beginning of one frame period are input from the clock generation circuit 6. In addition, a resolution designation signal for designating the resolution is input from the outside (for example, a microcomputer that controls the system of the entire apparatus).

The MCK signal is frequency-divided by a frequency divider 51 having an appropriate fixed frequency division ratio and input to a variable frequency divider 52. The variable frequency divider 52 is composed of a counter circuit or the like that counts the clock signal input from the frequency divider 51. The value input from the frequency division ratio setting circuit 53 is used as a load value and the FSY signal is used as a load signal. By inputting a load signal each time a carry signal is output from the counter circuit, the load signal is circulated at a predetermined frequency division ratio, and one pulse signal is generated as a motor drive pulse for each circulation. Also, the division ratio setting circuit 5
Reference numeral 3 is composed of a ROM or the like in which a value obtained in advance based on the moving speed of the photometric unit 10 with respect to the resolution is stored.

That is, in the motor drive circuit 5 having the above structure, it is possible to generate a number of motor drive pulses according to the resolution within one frame period in synchronization with the FSY signal.

Next, the movement control timing of the photometric unit 10 will be specifically described with reference to FIG. In FIG. 3, the vertical axis (t-axis direction) indicates the passage of time, and one scale (hereinafter referred to as “one unit time”) corresponds to one frame period. The horizontal axis (L-axis direction) indicates the photometric unit 10
2 shows a position in the X-axis direction on the surface of the sample 2 corresponding to a certain light receiving element of the CCD image sensor 17 when is moved. Therefore, one scale on the horizontal axis (hereinafter referred to as “one unit size”) corresponds to the minimum resolution in the X-axis direction that is determined by the spatial resolution of the photometric optical system. That is, the locus shown by the solid line in FIG. 3 (and FIG. 4) is accompanied by the movement of the photometric unit 10 at the center position of the area on the surface of the sample 2 corresponding to the projection image received by the light receiving element of interest. Showing movement. Further, the hatched area in the drawing indicates the area on the surface of the sample 2 which is reflected in the spectroscopic image due to the accumulation of charges in the light receiving element.

FIG. 3A shows a moving state of the photometric unit 10 by a general moving method in the conventional spectroscopic measuring device. That is, the photometric unit 10 is stopped during one frame period in which charge is accumulated in the CCD image sensor 17, and the photometric unit 10 is turned on during the next one frame period.
The unit size is moved in the X-axis direction. This allows
Although the resolution is good, the movement time of the photometric unit 10 is all lost in measurement time.

On the other hand, FIG. 3B shows the moving state of the photometric unit 10 when the resolution is reduced to half. In this case, a pulse signal is generated by the motor drive circuit 5 and applied to the pulse motor 4 so that the photometric unit 10 continuously moves at a speed of moving by one unit size per one unit time. The photometric unit 10 is moved even while the CCD image sensor 17 is accumulating electric charges, and the region on the sample 2 reflected in the spectral image of one frame extends over two adjacent unit sizes. That is, the average value of the range of the area having the size of 2 units is obtained from the spectral image of one frame.

As described above, by changing the moving speed of the photometric unit 10 according to the resolution, the average value of the range of the unit size on the sample 2 passing within one unit time can be obtained. Since the photometric unit 10 continues to move during the charge signal transfer time during which no charge is accumulated in one frame period, the position on the X-axis corresponding to the received light energy during that time should not be measured. However, since this charge signal transfer time is extremely short compared with the charge storage time, it can be practically neglected.

[Other Embodiments] In the above embodiment, the photometric unit 10 is continuously moved. However, the motor drive circuit as shown in FIG. 4 is used to perform the intermittent movement as shown in FIG. It is also possible to shorten the measurement time. In this case, the electronic shutter function of the CCD image sensor 17 is used. 4 is different from FIG. 2 in that
That is, the electronic shutter control signal (hereinafter referred to as “ESR signal”) is input to the AND gate 54 and the frequency division ratio setting circuit 53. The ESR signal is a control signal for closing the electronic shutter of the CCD image sensor 17 when it is at “H” level. Therefore, the clock signal to the variable frequency divider 52 is stopped while the electronic shutter is controlled to open. Further, the frequency division ratio setting circuit 53 detects the ratio of the period in which the electronic shutter is closed within one frame period by counting the “L” level period or the “H” level period of the ESR signal with the MCK signal. The division ratio to be set changes depending on the value.

In FIG. 5, the electronic shutter is opened for charge accumulation in the first half of one frame period, and the electric charge is accumulated in the latter half.
The two periods are examples when the electronic shutter is controlled to be closed. The photometric unit 10 is stopped while the electronic shutter is open and charges are accumulated, and is moved by one unit size while the electronic shutter is closed. In this case, it is necessary to realize the movement amount of the photometric unit 10 in one frame period in FIG. 3B within the latter half period.

Therefore, the clock signal is supplied to the variable frequency divider 52 only while the ESR signal is at the "H" level. Further, since the frequency division ratio setting circuit 53 detects that the electronic shutter is closed for half the time of one frame period, the one frame period in FIG. In order to generate the same number of pulse signals as that generated in (1), the value is set so that the frequency division ratio is 1/2 of that in the case of FIG. Accordingly, the motor drive pulse is not generated while the electronic shutter is open, and the number of drive pulses for obtaining the required movement amount can be generated while the electronic shutter is closed. As a result, the signal-to-noise ratio is degraded because the time for charge storage is shortened, but the measurement time is shortened.

The above circuit configuration is an example, and can be changed as appropriate. Further, although the photometric unit 10 is moved in the description of the above-mentioned embodiment, it goes without saying that the photometric unit 10 may be fixed and the sample stage 1 may be moved.

[Brief description of the drawings]

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

FIG. 2 is a configuration diagram of a motor drive circuit in FIG.

FIG. 3 is a schematic diagram for explaining movement control timing of a photometric unit.

FIG. 4 is a configuration diagram of a motor drive circuit according to another embodiment.

FIG. 5 is a schematic diagram showing another example of the movement control timing of the photometric unit.

FIG. 6 is a configuration diagram of a conventional spectroscopic measurement device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sample stand 2 ... Sample 3 ... Linear drive guide rail 4 ... Pulse motor (moving means) 5 ... Motor drive circuit 6 ... Clock generation circuit 10 ... Photometric unit 11 ... Light source 12 ... Slit 14 ... Diffraction grating (spectral means) 17 ... CCD image sensor (light detection means)

Claims (1)

[Claims] 1. A spectroscopic measurement device for spectroscopically measuring a two-dimensional area on a sample, wherein: a) a light source means for irradiating a one-dimensional area of the sample with light; and b) a plurality of minute light receiving elements are two-dimensional. And a photodetector that obtains a photodetection signal by accumulating an electric charge according to the received light energy by the photodetector, and c) projecting a one-dimensional region image of the sample in one dimension of the photodetector. And a diffusing means for dispersing light in the other dimension, and d) the light source means, the light detecting means and the spectroscopic means and the sample in a direction orthogonal to the one-dimensional area of the sample. Moving means for continuously moving either the photometric unit or the sample table on which the sample is placed for relative movement; and e) changing the moving speed of the moving means according to the desired resolution. , One frame in the light detecting means A spectroscopic measurement device comprising: a drive unit that generates a drive signal in synchronization with a cycle for obtaining a minute image signal.