JPS6154428A - Densitometer - Google Patents

Abstract

PURPOSE:To obtain a measurement signal having locality corrected by dividing the current photometric output at every position of a luminous flux scanning mechanism during measurement by locality correction data in a storage means which corresponds to the position. CONSTITUTION:A motor 4 is driven forward to check whether or not there is the detection signal of one hole of a hole array (b) generated by a detector 6; when B=1 is detected, the turning direction of the motor 4 is inverted and the motor is driven in the direction continuously. Consequently, luminous flux begins to scan from one end of a scanning range and it is checked whether the detection signal of the hole of a hole array (a) is present or not; when A=0, i.e. the falling of the detection signal is detected, a switch 16 is turned on and the output of a photoelectron multiplier tube 14 is inputted to a computer 18 and stored in the memory of the computer. Then, it is checked whether B=1 or not, and said operation is repeated until B=1. Thus, holes in the hole array (a) are detected, one by one, from one end and data on a photometric output are sampled at the falling of the detection signal and stored in the memory. Then, the largest value is retrieved in the memory and values obtained by dividing it by respective data are stored in the memory to obtain locality correction data.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a beam scanning densitometer, and particularly to its scanning mechanism. There are two types of densitometers: one type that scans by moving the sample in a zigzag pattern and the other type that scans by moving the light beam. However, in the type that moves the sample, the inertia of the moving part is large, making high-speed scanning difficult. A beam scanning type is suitable for high-speed scanning.

- Conventional technology In a densitometer, a method in which a sample spot to be measured is divided into minute parts for measurement enables background correction, scattering correction, etc., and improves quantitative performance. For this reason, the sample is irradiated with a thin beam of light and the sample is scanned by moving the sample and the beam relative to each other.However, the scanning method that moves the beam of light has a small mechanical part that performs high-speed reciprocating motion, making it difficult to perform high-speed scanning. It is possible. However, with this method, the energy of the spectrometer's output beam is non-uniform when viewed locally, and the direction of the sample irradiation beam and the direction of the sample spot's beam irradiation point as seen from the photodetector change with scanning. Because I do,
Because of the existence of so-called locality, in which the apparent sensitivity varies, the beam scanning densitometer remains a theoretical proposal, and no device that can be put to practical use as a quantitative measurement device is known yet.

C. Problems to be Solved by the Invention The present invention attempts to solve the above-mentioned locality in a beam scanning densitometer.

D1 Means for solving the problem: means for storing the correspondence between the position of the mechanism that moves the light beam for scanning and the photometric output of the sample photodetector, and storing the photometric output of the sample photodetector in the storage means. means for performing a locality correction calculation using the stored data, and the locality correction data is stored in the storage means by performing light beam scanning using a uniform sample plate.

E. Effect: Perform light flux scanning using a uniform sample plate. If data for each position of the optical scanning mechanism at that time and the photometric output of the photodetector corresponding to that position are stored in the storage means, these data can be stored. Since the data is collected using a uniform plate, if there was no locality, the same photometric value would correspond to all positions, but since locality exists, the photometric value is a function of the position of the optical scanning mechanism. By dividing this function by the photometric data corresponding to the position in the storage means and the locality correction data, a measurement signal with locality corrected is obtained.

Embodiment FIG. 1 shows an embodiment of the present invention. The light diffracted by the chain and the IM is focused on the exit slit surface of the spectrometer to form a spectral image. The exit slit extends in the vertical direction in the figure, and a scanning slit 3 is disposed in the exit loss lint. The scanning slit 3 is movable in the vertical direction in the figure, and is driven reciprocally up and down by a motor 4. With this structure, the light exit aperture of the scanning slit 3 scans the wavelength position where the spectral image is formed in the vertical direction. The monochromatic light emitted from the opening is reflected by the mirrors 7 to 8 and illuminates the stage surface of the sample stage S. The mirror 7 is a concave mirror that forms an image of the aperture on the stage surface, and while the image of the aperture is reciprocated in the vertical direction, the image of the stage surface is reciprocated in the X-axis direction. On the other hand, the stage S is driven in the y direction by the y direction feed motor Y, so the light beam irradiation point does not reciprocate in the X direction but moves in the y direction to scan the sample plate 9 set on the sample stage S in a zigzag manner. I will do it.

FIG. 2 shows the scanning slit 3 on an enlarged scale. A hole row a for position detection is provided on one side of the opening, and a scanning end detection hole is provided on the other side! A female is provided. Returning to FIG. 1, on both sides of the scanning slit 3, a photoelectric detector 5 is arranged across the hole array a, and a photoelectric detector 6 is arranged across the hole array. FIG. 3A shows the output signal of the photoelectric detector 5, in which one pulse is output each time one hole in the hole array a passes the photoelectric detector 5. B in the figure shows the output signal of the photodetector 6. When the opening of the scanning slit 3 reaches the end of the scanning range, one of the hole arrays comes to the position of the photoelectric detector 6, so the pulse in the signal B causes scanning. It is detected that the opening of the slit has reached the end of the scanning range.

Using these signals, when pulses A are counted after pulses B are detected, the counted value becomes data on the position of the opening of the scanning slit.

In Figure 1, l:L, 14 is a photomultiplier tube 0
A crystal plate 10 is obliquely inserted into the optical path of the light flux that enters the sample 9 from the mirror 8, and a part of the sample irradiation light is reflected and made to enter a photomultiplier tube 11 for use in monitoring the light source. The photomultiplier tube 14 is configured to receive the reflected light from the sample plate 9. The output of the photomultiplier tube 11, which receives the zero light source monitor light, is applied to the high voltage generation circuit 13 via the preamplifier 12, and the high voltage The output of the generating circuit 13 is fed to the dynodes of both photomultiplier tubes 11 and 14 so that the output of the photomultiplier tube 11 is constant, thereby compensating for fluctuations in the sample irradiation light.

A photomultiplier tube 1 that receives reflected light from a sample plate 9
The output of 4" is input to the computer 1 through the preamplifier 15, switch controller, and A/D converter 17. 019 is a motor drive circuit that drives motor 4 and motor Y. Motor Y is a pulse The drive pulses of the motor are sent to the computer 1, giving information on the position of the sample plate in the y-axis direction.20 is the data bus of the computer 1, and the output pulses of the photoelectric detectors 5 and 6 are also passed through this data path. FIG. 4 is a flowchart of the operation of the apparatus described above.

FIG. 4A shows the flow of the operation for obtaining locality correction data. At the start, the motor 4 is first driven in the forward direction, and the signal B in FIG. Check the presence or absence of (B=1) (b) L,,B
The motor 4 is driven until 1- is detected, and when step (b) becomes YES, the rotational direction of the motor 4 is reversed and the drive continues in that direction (2). As a result of this operation, the scanning of the light beam starts from one end of the scanning range, and in step (e), the signal A in FIG. The presence is checked, and if A-0 is detected in step (to), that is, hole row a
When the fall of the hole detection signal is detected, the switch 16
(Figure 1) is turned ON+))L, the output of the photomultiplier tube 14 is taken into the computer and stored (chip) in the memory within the computer.Next, in step (S), it is checked whether B=1 or not. , if B=O, the operation returns to step (d)° and the above-mentioned operation is repeated until B=1.In this way, the holes in hole row a are detected one by one from one end. Photometric output data is collected at the falling edge of the detection signal and stored in the memory. Figure 5 shows the inside of this memory, and the collected data is sequentially collected from the first photometric value to Ml, M2, . It will be stored in the location of (So)
When the step reaches YEf9, one scan ends.

Next, read the data M1, M2 from the memory, search for the maximum value Mx among them, and set Mx to each data M1, M2 . The value divided by ... is Ml, M2 in memory.
．． Reli to be replaced in the place of... Thus, the data (M x / M 1 ) r (M
X/M2), . . . become locality correction data.

FIG. 4B is a flowchart of the sample measurement operation. When the operation starts, the motor 4 is rotated in the forward direction (as in the case of Fig. 4A).
b) When the scanning slit 3 is driven until B=1 and the scanning start end is reached, the initial step is No (described later).
The motor 4 is reversed, and when A=1 is detected and then A=0 is detected (B), the switch 16 is turned ON, and the photometric output of the photomultiplier tube 14 is taken into the computer 18, and the data M x is transferred from the memory. /Ml is read out and multiplied by the photometric output data just taken in, stored in the sample measurement data storage area of the memory (c), and the above operation is performed in step (d).
Repeat until B=1 is detected, and each time the operation is repeated, the correction data is sequentially added to M X7M 1. Mx/M2
．． I'm going to change it to... Thus step (d) is YES
When S is reached, motor Y is rotated a certain amount to move the sample to the sample stage.
The motor 4 is moved in the y direction by a certain amount (e), and the motor 4 is rotated forward (
), and this time, photometric data is taken in at the rising edge of the signal A=1, that is, the detection signal of the holes in hole row a, and the correction data is taken out in reverse order from M x / M n and multiplied by the data just taken in. and stores it in the sample measurement data area of memory. This operation is repeated until E=1 (detection curse). In this case, the measurement value is acquired at the rising edge of signal A.In the previous process, the data was acquired at the falling edge of signal A, so in scanning in the reverse direction, the rising edge of A is positioned in the previous process. This is because it matches. When B = 1 is detected in step (g), the - round trip of scanning has been completed, so the stage S is
The stage S is driven by a certain amount in the direction and the operation returns to point X. When the movement of the stage S in the y direction reaches a certain distance, the step (S) becomes YES, and the measurement operation of - times is completed.

In the embodiments described above, the scanning slit 3 moves back and forth, but it is also possible to make the scanning slit endless so that it only scans in one direction.

G. Effect The densitometer of the present invention has the above-mentioned configuration and is a beam scanning type, so high-speed scanning is possible, and locality due to changes in the light receiving efficiency of the sample photodetector due to movement of the sample irradiation beam is corrected. Quantitativeness can be improved, and therefore pack-ground correction etc. can be performed, and quantitativeness can be further improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an apparatus according to an embodiment of the present invention, FIG. 2 is an enlarged front view of a scanning slit, FIG. 3 is a signal waveform diagram, and FIGS. The flowchart of the operation, FIG. 5, is a memory map showing the internal structure of a part of the memory in the above embodiment. M...Spectroscope, 1...Diffraction grating, 3...Scanning slit, 4...Motor for driving the scanning slit, 5, 6...
・・Photoelectric detector, 9...sample plate), 11.14・
. . . Photomultiplier tube, S . . . Sample stage, h . . . Opening of scanning slit, a . Agent Hiroshi Patent Attorney Figure 5 Figure 5

Claims (1)

[Claims] a mechanism for moving a light beam for sample scanning; a means for detecting each position of the mechanism during scanning; a means for storing the output of the sample photodetector in relation to the position of the mechanism; A densitometer comprising means for performing locality correction calculation on photometric output using data stored in the storage means.