JPH076763B2 - Swelling film thickness meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention measures and displays a film thickness that changes with time.
It relates to a film thickness meter for recording. In particular, the present invention relates to a swelling film thickness meter in which a coating film applied on a support absorbs and swells a liquid, and the state in which the thickness of the film changes is observed and recorded moment by moment.

For example, a photographic light-sensitive material such as a photographic film or photographic paper forms an image by treatment with a developing solution or the like, and the behavior of swelling of a photosensitive coating film in the treatment solution depends on the chemical reaction rate or the film formation during the treatment. It is known that the physical strength, the physical properties of the film after the treatment, and the finish quality such as surface appearance are closely related.Therefore, the swelling behavior can be measured in the design, process control, and quality control of photographic light-sensitive materials. It is indispensable.

(Prior Art and Problems) As a simple measuring method of the swelling behavior, there is a method of manually measuring a plurality of times by using a precision film thickness meter and plotting it manually. The precision film thickness meter used at this time includes a mechanical micrometer type and an electronic micrometer type, but in order to accurately measure while keeping the deformation of the measured object to a minimum by lowering the measurement pressure, An electronic micrometer using a differential transformer is suitable. In this method, a measuring terminal connected to a core in a cylindrical coil is brought into contact with the film surface, and a slight displacement thereof is measured as a change in impedance.

However, in the case of a photosensitive material in a processing solution, in order to measure the swelling behavior correctly, it is necessary to continuously measure the change occurring in a few seconds to a few tens of seconds. It was impossible to manually measure with the.

In addition, a method of continuously recording by connecting a recorder to an electronic micrometer type film thickness meter is also used. For example, a device for recording the displacement in the length direction of the film while continuously feeding the film is commercially available. Yes (Anritsu Denki film thickness measuring instrument).

However, in the case of measuring the swelling behavior, if the measurement terminal is fixed and the measurement terminal is kept in contact with the film that swells with time, the measurement terminal itself impedes the absorption of the liquid, and accordingly Swelling is hindered and accurate measurement is not possible.

In order to eliminate the influence of the measuring terminals, it is necessary to constantly move the measuring rod up and down while contacting the sample intermittently and for a short time. Curve was observed, and data was read from the curve only at the moment of contact, making accurate measurement extremely difficult.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a measuring method in which a measuring rod is constantly moved up and down and intermittently and briefly contacted with a sample. The purpose of the present invention is to realize a device that accurately extracts only the data at the moment of contact, that is, a swelling film thickness meter that momentarily observes and records the state in which the film thickness changes with time.

(Means for Solving Problems) The purpose is to reduce the measurement pressure applied to the swelling sample surface by 2 to
A cam drive unit that moves the measuring rod up and down with a low load of 15 g, a film thickness detecting unit equipped with a differential transformer that detects the displacement of the measuring rod, and a minimum peak value is detected from the output of the differential transformer. Then, using this as a trigger, the comparator for holding the output of the differential transformer after a certain period of time in the minimum peak hold circuit and the measuring rod are moved up and down in a certain cycle, and the output of the differential transformer is predetermined. Detecting that the trigger level has been passed,
This is achieved by a swelling film thickness meter characterized by comprising an intermittent sampling control section provided with a measurement trigger circuit for updating the hold value of the minimum peak hold circuit and the output value to the outside by using this as a trigger.

FIG. 1 is a system diagram showing the overall configuration of the present invention.

The entire system is roughly divided into a film thickness detection unit 1 and an intermittent sampling control unit 2.

The intermittent sampling control unit 2 includes an amplifier / low-pass filter 3, a track hold circuit 4, a differential amplifier 5, a minimum peak hold circuit 6, a sample hold circuit 7, a measurement trigger circuit 8, a controller 9, a comparator 10, and operation switches. 11, a digital display section 12, and an external output terminal 13.

FIG. 2 shows a schematic structural diagram of the film thickness detection unit 1.

The film thickness detection unit 1 includes a measurement rod 17, a differential transformer 14 that detects displacement of the measurement rod 17, and a cam drive unit 20 that moves up and down.

The measuring rod 17 is a cylindrical coil 15 of the differential transformer 14 at the top.
A contact jig 18 which is connected to a core 16 which is loosely fitted in the inside and which is in contact with the sample 22 is attached at the lower part.

The contact jig 18 attached to the tip of the measuring rod 17 is arranged close to the apex of the drum 21 around which the sample 22 to be measured is wound, and is arranged so as to be movable up and down.
The cam 17 and the contact jig 18 are periodically moved up and down by a cam drive unit 20 via a drive rod 19.

The intermittent sampling unit 2 operates by using the output of the differential transformer 14 as a trigger.

(Operation) In FIG. 2, a sample 22 is, for example, a water drop on an emulsion coating of a photographic photosensitive film, and a contact jig 18 attached to the tip of the measuring rod 17 from above.
Lightly touch. As a method for ensuring the fixation of the sample 22, a flat table provided with suction means may be used instead of the drum 21 in FIG.

In order to prevent the influence of the measurement pressure, the measurement rod 17 and the contact jig 18 are moved up and down by the cam drive unit 20 via the drive rod 19 at regular time intervals, for example, 0.5 second intervals. The measuring pressure is the core 16 of the differential transformer 14, the measuring rod 17,
Although it is determined by the total weight of the contact jig 18, it is desirable to be as light as possible in order to obtain an accurate swelling thickness, and a counter weight (not shown) is provided in the cam drive unit 20 to set the weight within a range of 2 to 15 g. Make it adjustable.

Further, it is important that the shape of the cam of the cam drive unit 20 has a shape that lowers the descending speed below the stroke so as not to give a strong impact at the moment when the contact jig 18 contacts the sample 22. .

Further, at the moment when the contact jig 18 of the measuring rod 17 comes into contact with the sample 22, a slight vibration is generated on the surface of the swollen sample 22. It is effective to sample and use the value after this, for example, the value after 0.1 second.

First, the flow of signals in the measurement mode will be described with reference to FIGS. 1 and 2.

As the measurement is started and the sample 22 swells, the film thickness becomes thicker, and the position when the measuring rod 17 and the contact jig 18 descend is increased with time.

Therefore, the output of the differential transformer 14 is the cam drive unit 20.
It is expressed by adding the component that the local minimum value rises with time to the periodic vertical movement that is moved by.

The output of the differential transformer 14 is input to the intermittent sampling control unit 2, first amplified by the amplifier / low-pass filter 3, and high-frequency noise, for example, high-frequency component of 20 Hz or higher is cut.

The next track-hold circuit 4 is a hold circuit for directly outputting the output of the differential transformer 14 to the digital display section 12, and does not function during continuous measurement.

The signal is further sent to the minimum peak hold circuit 6 and the comparator 10 after the zero point and the gain are adjusted by the differential amplifier 5. In the comparator 10, the signal is compared with a preset value, and the contact jig 18
Detects the minimum value at which the sample 22 comes into contact with the sample 22 and starts rising again, that is, the point where the rate of change in the output of the differential transformer 14 becomes zero, and instructs the controller 9 to hold the peak value. In response to this instruction, the minimum peak hold circuit 6 holds a value after a fixed time, for example, 0.1 seconds, and sends it to the next sample hold circuit 7.

On the other hand, the output of the differential transformer 14 is sent to the circuit of the measurement trigger 8 at the same time, and the trigger signal is issued to the controller 9 at the moment when the signal passes the preset voltage upward. Upon receiving this trigger, the controller 9 instructs the comparator 10 to detect a new minimum peak value, updates the hold value of the minimum peak hold circuit 6, and displays the value held in the sample hold circuit 7 on the digital display unit. 12 and output to the external output terminal 13.

Therefore, the waveform output to the digital display unit 12 and the external output terminal 13 is a stepwise waveform having one step of the length of one cycle of the vertical movement.

The processing of these signals can be handled in analog form up to the output, or can be processed and output in digital form after A / D conversion after the first stage amplification.

A feature of the present invention is that the output itself of the differential transformer 14 is used as a trigger. That is, in the measurement trigger circuit 8, the hold timing is updated and output timing is output, and in the comparator 10, the minimum peak sampling timing is instructed to the controller 9. That is, only the minimum peak value is output.

The time series relationship of the above operation will be described with reference to FIG.

In FIG. 3, the output of the differential transformer 14 is shown as a waveform that moves up and down.

This signal shows a signal waveform input to the minimum peak hold circuit 6, the measurement trigger circuit 8 and the comparator 10 in FIG.

In the figure, the output zero point level is the minimum value of the output of the differential transformer 14 before the start of swelling.

Now, immediately after the start of swelling, if the output of the differential transformer 14 passes upward at a predetermined measurement trigger level at point C ₀ , a trigger signal is sent to the comparator 10, which causes the differential transformer 14 to The output of 14 is compared with a preset comparator comparison reference level, the change in the difference is monitored, and the minimum peak value B ₀ is detected at the minimum point A ₀ .
The minimum peak hold circuit 6 holds this value.

When the next trigger signal is issued at the point C ₁ , the B ₀ value held in the minimum peak hold circuit 6 is transferred to the sample hold circuit 7 and held in the sample hold circuit 7, and at the same time, the digital display unit 12 And output to the external output terminal 13. Trigger signal generated by C ₁ point is also sent to the comparator 10 at the same time, the comparator
10 starts a new monitoring minimum values B _1, B ₁ with the following minimum point A ₁
When the value is detected, the minimum peak hold circuit 6 updates the minimum peak value B ₀ held so far to B ₁ .

Further, the minimum peak value B ₁ is transferred to the sample hold circuit 7 by the trigger signal generated at the next C ₂ point, and the output from the sample hold circuit 7 to the outside is updated from B ₀ to B ₁ . At the same time, the comparator 10 starts monitoring the next minimum peak value B ₂ .

In this way, the minimum peak values of the minimum peak hold circuit 6 and the sample hold circuit 7 are updated according to the trigger signal issued at each time of the periodic vertical movement, and the digital display section 12 and the external output terminal 13 are updated. The output to is updated.

Next, the operation of the other circuit units shown in FIG. 1 will be described.

The operation switch 11 is a "mechanical set mode" that directly reads the position of the core of the differential transformer 14, a "zero set mode" that sets the core position at that time to the zero point, a "measurement mode" that is selected during measurement, and a zero point. Also, four modes of "test mode" when adjusting the gain are selected.

The track hold circuit 4 holds and directly outputs the output of the differential transformer 14 after amplification when the "mechanical set mode" and the "zero set mode" are selected, and has a 12-bit A / D converter with a hold ing.

Further, in addition to the above-described minimum peak value detection function, the comparator 10 gives an instruction to cancel the hold instruction of the minimum peak hold value and remove it from the measured value when an abnormal value lower than the set comparison reference level appears. Is also provided to the controller 9, and the sample hold circuit 7 receives the instruction and outputs only the normal value. The abnormal value detection level is set lower than and close to the output zero point as shown in FIG.

The digital display unit 12 displays the signals corresponding to the above four modes as digital values. In the "mechanical set mode", the output of the amplifier / low-pass filter 3 bypasses the subsequent circuit and is directly displayed.

The external output terminal 13 is for a continuous recorder, and any recorder can be used.

(Example) An example is given in order to clarify the embodiment of the present invention.

In FIG. 2, the differential transformer 14 selected from commercially available products has an operating range of ± 2.5 mm and a measurement sensitivity of about 0.52 V / mm (when driven by DC).

In order to use the range with good linearity of the differential transformer 14, the range of zero set is 200 to 600 μm and the measuring range is 200 μm.

The measurement cycle is 0.5 sec, and the cam drive unit 20 makes it approximately 6 m.
Giving up and down strokes of m.

The output of the differential transformer 14 is the amplifier / low-pass filter 3
High frequency component of 20Hz or more is cut by 10mV / μ
Amplification was performed so that the sensitivity was m (2 V / 200 μm at the full scale of the measurement range), and thereafter this voltage range was maintained until the output.

The trigger level of the measurement trigger circuit 8 is 2.0 V, and the negative side abnormal value detection level of the comparator 10 is-.
It was set to 0.2V.

The linearity of the differential transformer 14 is 0.2% (±
Was equivalent to 5 μm), but the zero set level was 200-600
By setting the measurement range to be in the range of 0 μm to 0 μm to 200 μm, the measurement accuracy of ± 0.5 μm was obtained.

(Effects of the Invention) With the device of the present invention, since the measurement rod is moved up and down to bring it into contact with the sample intermittently, there is no error due to measurement pressure, etc., and the film thickness changes with time. Can be continuously and accurately measured.

Moreover, since the output itself of the differential transformer is used as a trigger, it is easy to perform measurement by arbitrarily changing the vertical movement cycle of the measuring rod, that is, the sampling and output periods, and it is possible to deal with various measurement targets. In particular, it is effective for observing and recording the state in which the coating film applied on the support absorbs and swells liquid and changes the film thickness, for example, the design, process control and quality of photographic light-sensitive materials. It has a great effect when used for management.

[Brief description of drawings]

FIG. 1 is a system diagram showing the overall configuration of the present invention, FIG. 2 is a schematic structural diagram of a film thickness detection unit, and FIG. 3 is a signal waveform of each step. 1 ... Film thickness detection unit 2 ... Intermittent sampling control unit 3 ... Amplifier / low pass filter 4 ... Track hold circuit 5 ... Differential amplifier 6 ... Minimum peak hold circuit 7 ... Sample hold circuit 8 ... Measurement Trigger circuit 9 …… Controller 10 …… Comparator 11 …… Operation switch 12 …… Digital display 13 …… External output terminal 14 …… Differential transformer 15 …… Cylindrical coil 16 …… Core 17 …… Measuring rod 18… … Contact jig 19 …… Drive rod 20 …… Cam drive unit 21 …… Drum 22 …… Sample

Claims (1)

[Claims] 1. The measurement pressure applied to the swelling sample surface is 2 to 15
A cam drive unit that moves the measuring rod up and down with a low load of g, and a film thickness detection unit equipped with a differential transformer that detects the displacement of the measuring rod, and a minimum peak value is detected from the output of the differential transformer. Then, using this as a trigger, the comparator for holding the output of the differential transformer after a certain period of time in the minimum peak hold circuit and the measuring rod are moved up and down in a certain cycle, and the output of the differential transformer is predetermined. Swelling characterized by comprising an intermittent sampling control section equipped with a measurement trigger circuit for detecting that a trigger level has been passed and updating the hold value of the minimum peak hold circuit and the output value to the outside by using this as a trigger. Film thickness meter.