JPH08247728A - Dimension measuring device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a relatively small size measuring device at a low price. [Structure] Light from a light projecting element 1 is converted into parallel light 3 by a lens 2 and irradiated onto a measurement object 4, and the projection is received by a CCD image sensor 5. The output of the CCD image sensor 5 is binarized by the comparator 8, the gate corresponding to the shaded portion of the binarized signal is created by the gate generator, and the integrator 1
In 4, the reference voltage is integrated over the gate period, and the integrated value is output in analog.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dimension measuring device which uses a one-dimensional light receiving sensor such as a CCD image sensor to output measured values in analog form.

[0002]

2. Description of the Related Art Conventionally, there is a dimension measuring apparatus shown in FIG. 6 which measures the dimension of an object to be measured by using a CCD image sensor and outputs the measured value as an analog value. This size measuring device includes a light projecting element 1 and a lens 2 for irradiating a light beam from the light projecting element 1 as a parallel light beam 3 onto an object to be measured 4.
Then, the parallel light beam 3 that has passed through the region including the measurement object 4 is received, and by the clock from the clock source 6,
CCD image sensor 5 that serially outputs light receiving signals
A filter 7 for removing unnecessary components such as noise in the output of the CCD image sensor 5; a comparator 8 for binarizing the output of the CCD image sensor 5 with a predetermined threshold; and a comparator for measuring mode setting. 8, a gate generator 9 for generating a gate signal in accordance with the output of the counter 8, a counter 11 for counting the clock signal from the high-speed clock source 10 between the gates of the gate signal, and a latch circuit 12 for latching the count value of the counter 11. And the latch circuit 1
A D / A converter 13 for converting the count value latched at 1 into an analog signal and outputting the analog signal is provided, and an analog signal corresponding to the measured value is output.

[0003]

In the above-described conventional dimension measuring apparatus, the width of the dark portion corresponding to the projected portion of the measuring object and the width of the surrounding bright portion are measured by counting the clock signal. In order to increase the resolution, it is necessary to use a high-speed clock, use a large number of bits in the counter, and use a large number of bits in the A / D converter. However, there was a problem that the external dimensions of the product also increased.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a low-priced and relatively small size measuring apparatus.

[0005]

The dimension measuring apparatus of the present invention irradiates a measuring object with a parallel light beam, receives the parallel light beam from the measuring object with a one-dimensional light receiving sensor, and measures the measuring object. In a device for measuring a dimension of an object and outputting a measured value in an analog manner, the comparator for binarizing the output of the one-dimensional light receiving sensor, a gate generator for generating a gate signal for integration by the output of the comparator, and a gate An integrating circuit for integrating the reference voltage is provided between the gates of the signals.

In this dimension measuring device, the serial output signal of the one-dimensional light receiving sensor is binarized by the comparator, and the binarized signal is input to the gate generator to generate the gate signal. The reference voltage is integrated by the integrating circuit over the gate period, and the measured value is output as an analog signal.

[0007]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a block diagram showing the configuration of a dimension measuring apparatus according to an embodiment of the present invention. The dimension measuring apparatus according to this embodiment includes a light projecting element 1, a lens 2, a CCD image sensor 5, a clock source 6, a filter 7, a comparator 8, and a gate generator 9. The above configuration is
This is the same as the conventional dimension measuring device shown in FIG. The dimension measuring apparatus of this embodiment further includes an integrator (integrating circuit) 14 that integrates and outputs the reference voltage over the gate period of the gate signal output from the gate generator 9. This integrated output becomes an analog signal according to the measured value.

In the dimension measuring apparatus of this embodiment, the light emitted from the light projecting element 1 at the time of measurement is converted into a parallel light beam 3 by the lens 2 and applied to the object 4 to be measured. The parallel light beam 3 passes through the region of the measurement object 4 and enters the CCD image sensor 5. Of the parallel light beam 3, the portion of the measuring object 4 is blocked and becomes a shadow, which is not input to the CCD image sensor 5. That is, the shadow of the measuring object 4 is projected on the CCD image sensor 5, and the light entering the CCD image sensor 5 has a bright portion and a dark portion. The output signal serially output has the waveform shown in FIG.

The output signal of the CCD image sensor 5 is input to a comparator 8 through a filter 7 and compared with a preset threshold value to be binarized. The gate generation unit 9 receives the binarized signal and outputs the gate signal of any one of section 1, section 2, and section 3 set in the measurement mode setting. The gate signal is, as shown in FIG. 2B, a section 1 corresponding to the width of the first bright portion, a section 2 corresponding to the width of the dark portion, and a section 3 corresponding to the last bright portion. Select one of them to output according to the setting. The integrator 14 integrates the reference voltage V during the gate period of the input gate signal and outputs it as an analog signal. In the case of the gate in the section 1, its integrated waveform is (a) in FIG.
In the case of the gate in the section 2, the integrated waveform is shown in FIG. 3B, and in the case of the gate in the section 3, the integrated waveform is shown in FIG.
(C). In both cases, the final value of the section is sampled and held (S / H) and output. Section 1 here
Is specifically applied for positioning, for example, the section 2 is used for the outer diameter of the measuring object, and the section 3 is used for positioning.

FIG. 4 is a circuit diagram showing a concrete example of the integrator 14. In this integrator, the reference voltage V is passed through a gate circuit 21 and a resistor R ₂₁ which are opened and closed by a gate signal,
A gate circuit 23 connected to be added to the inverting input terminal (−) of the OP amplifier 22 and opened / closed by a reset signal between the inverting input terminal (−) and the output terminal of the OP amplifier 22 and a capacitor C ₂₁ for integration. Are connected in parallel, and the non-inverting input terminal (+) of the OP amplifier 22 is grounded. The output terminal of the OP amplifier 22 has a gate circuit 2 which is opened / closed by a sample hold signal S / H.
4. A holding capacitor C ₂₂ is connected between the inverting input terminal (−) of the OP amplifier 25 via the resistor R ₂₂ and between the output side of the gate circuit 24 and the ground.
The non-inverting input terminal of the OP amplifier 25 (+) is connected to ground, inverting input terminal (-) and a resistor R ₂₃ is connected between the output terminal and is configured. However, this integrator itself is usually used frequently, and is not a circuit with special characteristics.

In the integrator 14, the gate circuit 21
5 is input, the gate circuit 21 is opened during that time, the reference voltage V is applied to the OP amplifier 22, and the reference voltage V is integrated as shown in FIG. When the falling light of the gate signal is reached, the sample hold signal S / H shown in FIG. 5 is applied to the gate circuit 24 and the gate circuit 24 is opened. As a result, the OP amplifier 22
The integrated output of is led to the output side through the gate circuit 24 and held in the capacitor C ₂₂ . After the hold, the reset signal shown in FIG. 5 is applied to the gate circuit 23, the gate circuit 23 is opened, and the integrated voltage of the capacitor C ₂₁ is reset. The analog output of the OP amplifier 25 is shown in FIG.
As shown in, the hold value is output every sample hold time.

[0012]

According to the present invention, since a high speed clock is not used and an analog signal is output by integration,
Low radiation noise and high noise resistance. Further, since the clock is not used for the dimension calculation, no quantization error occurs. Since no space-consuming parts such as a counter, a latch circuit, and a clock source are used, the size can be reduced. Since an expensive D / A converter is not used and the number of parts is reduced, it is possible to achieve an effect such as cost reduction.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a dimension measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an output waveform and an integration section of a CCD image sensor of the size measuring apparatus according to the embodiment.

FIG. 3 is a diagram illustrating an integrated output of the dimension measuring apparatus according to the embodiment.

FIG. 4 is a circuit diagram showing a specific example of an integrator of the dimension measuring apparatus of the embodiment.

FIG. 5 is a waveform diagram for explaining a circuit operation of the integrator.

FIG. 6 is a block diagram showing a configuration of a conventional dimension measuring device.

[Explanation of symbols]

 1 Projection Element 2 Lens 3 Parallel Light Beam 4 Object to be Measured 5 CCD Image Sensor 8 Comparator 9 Gate Generation Section 14 Integrator

Continuation of the front page (72) Inventor, Yoshida, Tofu, Kyoto Prefecture Omron Co., Ltd. 10 Hanazono Dodocho, Ukyo-ku, Kyoto City

Claims (1)

[Claims] 1. A dimension for irradiating a measurement object with a parallel light beam, receiving a parallel light beam from the measurement object with a one-dimensional light receiving sensor, measuring the dimension of the measurement object, and outputting the measured value in analog form. In the measuring device, the comparator for binarizing the output of the one-dimensional light receiving sensor, the gate generator for generating a gate signal for integration by the output of the comparator, and the integral for integrating the reference voltage between the gates of the gate signals. A dimension measuring device comprising: a circuit.