JPS63300941A - Zero correcting device for optical measuring instrument - Google Patents

Abstract

PURPOSE:To speedily and accurately perform zero correction by connecting the control circuit of an optical correcting mechanism to a light receiving body electrically and connecting an electric zero correcting circuit to the output side of a light receiving body output amplifying circuit. CONSTITUTION:Light P from a light source lamp 1 passes through a sample cell 2 and is reflected by a reflecting mirror 3 to make it incident on the light receiving body 5 through a glass plate 4. When light P1 is not incident on a sample-side photodetector and a reference-side photodetector element equally, the light receiving body 5 outputs a corresponding signal to the control circuit 6. Then the glass plate 4 is moved by a control motor 8 with said signal so that the light is incident on both photodetectors equally, and thus the optical axis to the light receiving body 5 is moved in parallel to make an optical zero correction. Then the electric zero correcting circuit 7 is connected to the output side of the control circuit 6 to make an electric zero correction. Consequently, the optical correcting mechanism and electric zero correcting circuit operates associatively to make the electric zero correction while maintaining optical balance.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a one-port correction device for various optical measuring instruments such as a differential refractometer and a spectrophotometer 51.

That is, most of the detection mechanisms in optical measuring instruments are of a type that converts the difference between the energy level of light before starting measurement and the energy level of light during measurement into an electrical signal. Therefore, in this case, it is of course necessary to set the output to display ze[1 before starting the measurement, and the mechanism for setting this output to zero is called a zero correction mechanism (device).

<Prior art> The mechanism for automatically performing this type of edge correction includes an optical auto-zero method in which the light incident on the photoreceptor is controlled by an optical compensation iF and B11 structure, and an optical auto-zero method that controls the light incident on the photoreceptor by adjusting the error voltage before starting the measurement. There is an electrical auto-zero method in which a corresponding voltage is applied externally to cancel it out. Since the optical auto-zero method can always keep the light energy the same before starting measurement, it is possible to improve the linearity of the check line that shows the relationship between sample concentration and output during measurement due to fluctuations in energy level. It has the advantage that the range is always constant, but optical correction B for adjusting the optical axis and optical axis incident on the photoreceptor! Since the side must be driven by a control motor, it takes time to perform the zero correction, and if the drive is made faster, there is a problem in that the M range of the gap correction decreases. Further, although the electrical auto-zero method has a fast zero-baldness correction time, it does not perform balance correction of the optical energy level, so there is a problem in that the measurement value is required to be corrected due to fluctuations in the margin line.

<Problems to be Solved by the Invention> The present invention has been made in view of these conventional problems, and can significantly reduce the time required for zero correction compared to the conventional optical auto-zero method. At the same time, the accuracy of zero correction can be made to be on the same level as the conventional optical auto-zero method, and the optical energy level balance is always the same before starting measurement, and the linearity and linearity range of the calibration curve are always maintained. It is an object of the present invention to provide a zero correction device for an optical measuring instrument that can be maintained constant.

Means for Solving the Problems〉 The zero correction device in the optical measuring instrument of the present invention that achieves the above object has a control circuit for an optical correction mechanism that controls the light incident on the photoreceptor, which is electrically connected to the photoreceptor. In addition, an electrical zero correction circuit is connected to the output side of the photoreceptor output amplification circuit.

<Example> Hereinafter, Example 3 of the present invention will be explained based on the drawings.
The figure shows an example of a differential refractometer, and Fig. 3 shows an example of spectroscopic light revision. It will be easily understood from the following description that the device of the present invention can be applied to any optical measuring instrument equipped with a detection mechanism that converts

In FIG. 1, 1 is a light source lamp, and light P from this light source lamp 1 passes through a sample cell 2, is reflected by a reflecting mirror 3 installed behind the sample hill 2, passes through a glass plate 4, and then passes through a C.
The light enters the photoreceptor 5. The light energy incident on the photoreceptor 5 is converted into electrical energy by the photoreceptor 5, amplified by the control circuit 6, and output to the electrical zero correction circuit 7. In the optical system from the reflector 3 to the photoreceptor 5, the control motor 8 is driven by a signal from the control circuit 6 to move the angle of the glass plate 4, thereby moving the optical axis incident on the photoreceptor 5 in parallel. , performs optical zero correction before starting measurement. That is, the optical correction mechanism that controls the light P+ incident on the photoreceptor 5 is composed of a glass plate 4, a control motor 8 for moving the glass plate 4, and a control circuit 6 for driving the control motor 8. The circuit 7 is electrically connected to the photoreceptor 5, and the light P+ incident on the photoreceptor 5 consisting of the sample-side photoreceptor and the control-side photoreceptor in the state before the start of measurement is received by the sample-side photoreceptor and the control-side photoreceptor. If the light is not evenly incident on the photoreceptor 5,
A corresponding signal is outputted from the control circuit 6 and applied to the control circuit 6, and the glass plate 4 is moved by the control motor 8 so that the light is evenly incident on the sample-side light-receiving element and the control-side light-receiving element. , optical zero correction is performed by moving the optical axis incident on the photoreceptor 5 in parallel.

Next, an electrical zero correction circuit 7 is connected to the output side of the control circuit 6 to perform electrical zero correction.

This electrical zero correction circuit 7 is a circuit that applies a voltage corresponding to the error voltage before the start of measurement from the outside to cancel it out. Basically, as shown in FIG.
A comparator 20 for determining the magnitude (plus/minus) of the voltage manually applied from the
an up/down counter 21 that adds or subtracts voltage according to the determination of
It consists of

However, if the light P1 incident on the photoreceptor 5 is not equally incident on the sample-side light-receiving element and the control-side photoreceptor in the state before the start of measurement, the photoreceptor 5 outputs a corresponding signal. Therefore, the signal is not inputted from one input terminal 23 of the differential amplifier 22, and its output is inputted to the comparator 20. The comparator 20 compares and determines whether the voltage difference of the input signal is on the IIIGII side or the [○- side with respect to the L port V, and according to the result of the determination, the up/down counter 21 is used to determine whether it is on the old Gll side. performs addition, and when it is ○-, it performs subtraction, +IN and -IN
When the inputs of are balanced, up/down counter 2
1 is balanced, maintains an equilibrium state, and outputs it to the differential amplifier 22.

If this up/down counter 21 is latched when it is in a balanced state, its output voltage will continue to hold the voltage of IL1 even if the input voltage changes until the latch is released. Electrical zero correction is now performed.

Further, FIG. 3 shows an example of a spectrophotometer, in which 9 is a half mirror for distributing the incident light P into a sample-side photoreceptor 5a and a control-side photoreceptor 5b, 10a, 10.
b is a diaphragm (slit) for adjusting the light incident on the photoreceptors 5a and 5b, and the same reference numerals as in FIG. 1 indicate the same components. In this example, the optical correction mechanism that controls the light P incident on the photoreceptors 5a and 5b is composed of a half mirror 9, a control motor 8 for moving the half mirror 9, and a control circuit 6 for driving the control motor 8. Ru. That is, if the amount of light incident on the sample-side photoreceptor 5a and the control-side photoreceptor 5b is not equal in the state before the start of measurement, a corresponding signal is output to the 1.11111 circuit 6 to the sample-side photoreceptor 5b. Optical zero correction is performed by changing the reflection angle of the half mirror 9 via the control motor 8 so that the energy (light amount) of the light incident on the photoreceptor 5a and the contrast side photoreceptor 5b becomes equal.

Note that even when using a single photoreceptor that does not require the contrasting photoreceptor 51), optical zero correction can be performed by similarly changing the light I11 that reaches the sample cell 2. The output of the control circuit 6 is then outputted through the electrical mouth correction circuit 7 described above.

<Effects of the Invention> Since the pyro correction ￥7 device in the optical measuring instrument of the present invention is configured in this manner, when performing the zero supplement low operation before starting measurement,
The optical correction mechanism (optical auto-zero mechanism) and the electrical zero correction circuit (electrical auto-zero [1 mechanism) work together, so it is possible to perform electrical zero correction while maintaining optical balance. The gap can be corrected quickly and accurately without causing large deviations in output caused by optical imbalance. In other words, since the optical correction mechanism works only to return the optical balance to a range where no change in the inspection line occurs, the speed limit for increasing accuracy is greatly relaxed, and as a result, the time required for zero correction is reduced. This can be significantly shortened compared to the conventional optical auto-zero method.18 Also, since the electrical zero correction range can be limited to the optical zero correction range, the zero correction accuracy can be improved compared to the conventional optical auto-zero method. It is possible to maintain the same level as the auto-zero method.

Moreover, since the basic zero correction is performed by an optical correction mechanism (optical auto-zero mechanism), the optical energy level balance is always the same before starting measurement, and the linearity and linearity range of the detection line are always maintained. It can be held constant, and there is no possibility that the calibration curve will change due to poor optical balance due to accumulation of repeated corrections. Figure 4 is a graph showing this effect. The tIX axis shows the magnitude of the output, the horizontal axis shows the magnitude of the deviation in optical balance, and the output obtained by the sample concentration caused by poor optical balance. It can be seen that there is no change in the signal magnitude.

J: Is it possible to achieve the intended purpose?

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the first embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of implementation of the electrical gap correction circuit according to the present invention, and FIG. 3 is a schematic diagram showing the embodiment of the present invention shown in FIG. The schematic diagram shown in FIG. 4 is a graph explaining the effect of the device of the present invention. In the figure, 5.5a and 5b are photoreceptors, 6 is a control circuit, and 7 is an electrical zero correction circuit. Patent applicant Elma Co., Ltd./゛′ Agent Hayakawa
Government ＼ Name 7pa' and-・

Claims (1)

[Claims] A control circuit for an optical correction mechanism that controls light incident on the photoreceptor is electrically connected to the photoreceptor, and an electrical zero correction circuit is connected to the output side of the photoreceptor output amplification circuit. Zero correction device for optical measuring instruments.