Inspection apparatus

Abstract

To provide an inspection device for improving inspection accuracy of sealing performance of a sealed container.SOLUTION: The laser generator 2 generates a laser beam LL that is irradiated from the outside of the sealed container 10 toward the sealed container 10. The photodetector 3 receives the laser light LL that has passed through the sealed container 10. The signal processor 5 obtains a first parameter 1f based on the V1 signal detected from the light receiving signal of the laser beam LL, obtains a second parameter 2f based on the V2 signal detected from the light receiving signal, and inspects the sealing performance of the sealed vessel 10 based on the second parameter V2 / the first parameter V1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an inspection device. [Background technology]

[0002] Patent Document 1 discloses an inspection device that inspects the hermeticity of sealed containers such as vials. The device disclosed in Patent Document 1 emits light from a narrowband laser light source toward the sealed container from outside the sealed container. The absorption signal of the light scattered within the sealed container is measured, and the hermeticity of the sealed container against a target gas is detected from the measured absorption signal.

[0003] However, the absorption signal described above varies not only with the gas concentration of the target gas but also with fluctuations in the light receiving power (including differences in insertion loss between sealed containers, fluctuations in the output of the laser light, and changes in the sensitivity of the light receiver that receives the laser light). For this reason, conventional devices have had the problem of being unable to accurately inspect the hermeticity of sealed containers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2012-526973 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an inspection device that improves the accuracy of inspecting the hermeticity of a sealed container. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the inspection device according to the present invention has the following features. a laser generating unit (2) that generates a laser beam (LL) that is irradiated from the outside of the sealed container (10) toward the sealed container; a light receiving unit (3) that receives the laser light after passing through the head space of the sealed container; and an inspection unit (5) that inspects the hermeticity of the sealed container based on the light receiving signal of the light receiving unit. In the inspection device (1), the laser generating unit generates the frequency-modulated laser light, the inspection unit determines a first parameter based on the light receiving signal or a frequency component of a fundamental wave of the modulation frequency of the laser light detected from the light receiving signal, determines a second parameter based on the light receiving signal or a frequency component of an n-th multiple wave (n is an integer equal to or greater than 1) of the modulation frequency of the laser light detected from the light receiving signal, and inspects the hermeticity of the sealed container based on a ratio between the first parameter and the second parameter. It is an inspection device (1). In the above inspection device, the inspection unit determines a first parameter based on a frequency component of a fundamental wave of the modulation frequency of the laser light detected from the light receiving signal, determines a second parameter based on a frequency component of a double wave of the modulation frequency of the laser light detected from the light receiving signal, and inspects the hermeticity of the sealed container based on a ratio between the first parameter and the second parameter. It is an inspection device. In the above inspection device, the inspection unit determines a first parameter based on the light receiving signal, determines a second parameter based on a frequency component of a second harmonic of the modulation frequency of the laser light detected from the light receiving signal, and inspects the hermeticity of the sealed container based on a ratio between the first parameter and the second parameter. It is an inspection device.

[0007] According to the above configuration, by inspecting the hermetic seal based on the ratio between the first parameter and the second parameter, the influence of fluctuations in the received light power can be offset, and therefore the hermetic seal of the sealed container can be inspected with high accuracy. [Effects of the Invention]

[0008] The inspection device according to the present invention has the effect of improving the inspection accuracy of the hermeticity of a sealed container.

[0009] The present invention has been briefly described above. The details of the present invention will become clearer by reading the following detailed description of the invention (hereinafter referred to as "embodiments") with reference to the accompanying drawings. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing an embodiment of an inspection device according to the present invention. [Figure 2] FIG. 2 is a perspective view of the appearance of the inspection device shown in FIG. [Figure 3] FIG. 3 is a flowchart showing the procedure of the seal inspection process executed by the signal processing unit shown in FIG. [Figure 4] FIG. 4 is a graph showing the wavelength characteristics of the 1f signal detected from the light reception signal of the photodetector shown in FIG. [Figure 5] FIG. 5 is a graph showing the wavelength characteristics of the 2f signal detected from the light reception signal of the photodetector shown in FIG. [Figure 6] FIG. 6 is a graph showing the wavelength characteristics of the light reception signal of the photodetector shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0012] 1 and 2, the inspection device 1 of this embodiment is an inspection device that inspects the hermeticity of a sealed container 10 such as a sealed vial. The sealed container 10 is not limited to a vial, but may be any container that requires high hermeticity.

[0013] The inspection device 1 of this embodiment uses a headspace gas laser analysis method as a method for inspecting the hermetic seal of a sealed container 10. As shown in FIG. 1, the inspection device 1 transmits laser light LL of a predetermined wavelength through a space inside the sealed container 10, i.e., a headspace 10A, which is the space other than the substance 10B (liquid, solid, powder, etc.) enclosed in the sealed container 10. The inspection device 1 inspects the hermetic seal of the sealed container 10 based on a received signal of the laser light that has been absorbed by the target gas (e.g., oxygen) and has passed through the sealed container 10.

[0014] As shown in FIG. 1, the inspection device 1 includes a laser generating unit 2, a photodetector 3 as a light receiving unit, an A / D conversion unit 4, a signal processing unit 5 as an inspection unit, and a display unit 6.

[0015] The laser generating unit 2 generates laser light that is irradiated from outside the sealed container 10 toward the sealed container 10. In this embodiment, the laser generating unit 2 has a ramp wave generator 21, a sine wave generator 22, a bias tee 23, a laser driver 24, and a laser diode 25.

[0016] The ramp wave generator 21 generates a ramp wave W1 and inputs it to the bias-tee 23. The sine wave generator 22 generates a sine wave W2 of a predetermined frequency and inputs it to the bias-tee 23. The bias-tee 23 inputs a signal obtained by adding the ramp wave W1 and the sine wave W2 to the laser driver 24. The laser driver 24 inputs a drive current corresponding to the signal input from the bias-tee 23 to the laser diode 25. The wavelength of the laser diode 25 is the central wavelength of one absorption spectrum of the target gas. The laser diode 25 generates laser light modulated with the frequency of the sine wave W2. In this embodiment, the laser diode 25 outputs wavelength-swept laser light LL.

[0017] The photodetector 3 outputs a light reception signal corresponding to the intensity of the received laser light LL.

[0018] The A / D conversion unit 4 receives the light reception signal from the photodetector 3 and the sine wave W2 from the sine wave generator 22. The A / D conversion unit 4 converts the received light signal and sine wave W2 into digital values ​​and inputs them to the signal processing unit 5.

[0019] The signal processing unit 5 is made up of a computer that operates according to a program. The signal processing unit 5 processes the received light signal and the sine wave W2 to inspect the hermeticity of the sealed container 10.

[0020] As shown in Fig. 2, the inspection device 1 also includes a transport unit 7 that transports a plurality of sealed containers 10 in sequence to a seal inspection area A1 sandwiched between the laser diode 25 and the photodetector 3. The transport unit 7 has a transport table 71 and a disk-shaped transport disk 72 that rotates on the transport table 71. The transport disk 72 is configured to rotate clockwise in Fig. 2, and has a plurality of holding portions 72A formed at predetermined intervals on its outer periphery, each of which is semicircularly cut out radially inward. The holding portions 72A are configured to hold the sealed containers 10.

[0021] A supply unit 8 is connected to the transport unit 7, which sequentially supplies sealed containers 10 from the previous process to the transport unit 7. The transport unit 7 receives the sealed containers 10 supplied from the supply unit 8 into a holder 72A, and transports the received sealed containers 10 to the sealability inspection area A1 by rotating while the holder 72A holds the sealed containers 10. A laser diode 25 is arranged on one side of the radial direction of the sealability inspection area A1, and a photodetector 3 is arranged on the other side of the radial direction of the sealability inspection area A1. When the sealed container 10 is transported to the sealability inspection area A1, the sealed container 10 is positioned between the laser diode 25 and the photodetector 3, and laser light LL is irradiated onto the headspace of the sealed container 10.

[0022] The transport unit 7 transports the sealed containers 10 that have passed through the sealability inspection area A1 to the moisture inspection area A2, and transports the sealed containers 10 that have passed through the moisture inspection area A2 to the discharge area A3. The discharge area A3 of the transport unit 7 is connected to a discharge unit 9 that discharges the sealed containers 10. The discharge unit 9 has a moisture NG discharge path 91, a sealability NG discharge path 92, and an OK discharge path 93.

[0023] The moisture NG discharge path 91 is a discharge path through which sealed containers 10 with an inappropriate moisture content based on the moisture test results are discharged. The sealability NG discharge path 92 is a discharge path through which sealed containers 10 with insufficient sealability based on the sealability results are discharged. The OK discharge path 93 is a discharge path through which sealed containers 10 with an appropriate moisture content and ensured sealability are discharged.

[0024] In this embodiment, the sealed container 10 transported from the supply unit 8 to the transport unit 7 is in a sealed state with the head space 10A replaced with a gas. That is, the sealed container 10 supplied to the transport unit 7 is sealed with the gas in the head space 10A replaced with an inert gas. In this embodiment, nitrogen gas is used as the inert gas used for gas replacement.

[0025] As a gas replacement method, for example, a gas replacement method using a gas replacement device is used, in which an inert gas is filled into the sealed container 10 from a nozzle different from the nozzle used to fill the substance when sealing the substance into the sealed container 10. The gas replacement method using a gas replacement device is not limited to the above-mentioned method, and various other methods can be used, such as a method of performing gas replacement by spraying an inert gas directly into the opening of the sealed container 10 after filling the substance.

[0026] Next, the inspection of the hermeticity of the sealed container 10 performed by the inspection device 1 having the above-described configuration will be described with reference to Fig. 3. Fig. 3 is a flowchart showing the procedure of the hermeticity inspection process performed by the signal processing unit 5 of the inspection device 1. The signal processing unit 5 of the inspection device 1 performs the hermeticity inspection process every time the sealed container 10 is transported to the hermeticity inspection area A1.

[0027] First, the signal processing unit 5 receives the digital values ​​of the received light signal and the sine wave W2 converted by the A / D conversion unit 4 (S1). In S1, the signal processing unit 5 receives the digital values ​​of the received light signal and the sine wave W2 sampled multiple times during one wavelength sweep. The received light signal has a waveform with an attenuated signal level according to the gas concentration of the target gas at the absorption wavelength λc of the target gas.

[0028] More specifically, the laser light LL is absorbed by the target gas at the absorption wavelength λc of the target gas, resulting in a decrease in the received light signal. Wavelengths away from the absorption wavelength λc are not absorbed by the target gas, so the received light signal does not decrease. That is, the signal level of the received light signal at the absorption wavelength λc depends on the gas concentration of the target gas and the received light power (including the output power of the laser light LL, the insertion loss of the sealed container 10, etc.). Naturally, the signal level of the received light signal at wavelengths away from the absorption wavelength λc depends only on the received light power.

[0029] Next, the signal processing unit 5 detects a signal (1f signal) with the same frequency component (= frequency component of the fundamental wave) as the sine wave W2 from the received light signal (S2). In S2, the signal processing unit 5 functions as a lock-in amplifier, and passes the signal obtained by multiplying the received light signal by the sine wave W2 through a low-pass filter to detect the 1f signal. As shown in Figure 4, the 1f signal is a waveform obtained by differentiating the waveform of the received light signal. More specifically, the waveform of the 1f signal is constant at signal level A at the absorption wavelength λc and wavelengths away from the absorption wavelength λc, and rises or falls from signal level A at wavelengths around the absorption wavelength λc. This signal level A is not affected by the gas concentration of the target gas, and is a value that depends only on the received light power. The signal processing unit 5 determines the signal level A of the 1f signal as parameter V1 (= first parameter) (S3).

[0030] In S3, the signal processing unit 5 may determine the signal level A of a wavelength away from the absorption wavelength λc and set it as the parameter V1, or may determine the signal level A of the absorption wavelength λc and set it as the parameter V1.

[0031] Next, the signal processing unit 5 detects a signal (2f signal) with a frequency component twice that of the sine wave W2 from the captured received light signal (S4). In S4, the signal processing unit 5 functions as a lock-in amplifier, and passes the signal obtained by multiplying the received light signal by the doubled wave of the sine wave W2 through a low-pass filter to detect the 2f signal. As shown in Figure 5, the 2f signal has a waveform obtained by differentiating the waveform of the 1f signal shown in Figure 4. More specifically, the signal level of the 2f signal becomes 0 at wavelengths sufficiently far from the absorption wavelength λc and peaks at the absorption wavelength λc. The signal level B of the 2f signal at the absorption wavelength λc depends on the gas concentration of the target gas and the received light power. The signal processing unit 5 calculates the signal level B of the 2f waveform as parameter V2 (= second parameter) (S5).

[0032] Next, the signal processing unit 5 calculates the parameter V2 / parameter V1 (S6). The parameter V2 / parameter V1 is a value that is not affected by fluctuations in the received light power. Thereafter, the signal processing unit 5 inspects the hermetic seal based on the value of the parameter V2 / parameter V1 (S7) and ends the process. In S7, for example, if the value of the parameter V2 / parameter V1 is higher than a threshold, the hermetic seal inspection is judged as failing (NG), and if it is lower than the threshold, it is judged as passing (OK).

[0033] In addition, in S7, the signal processing unit 5 displays the inspection result of the sealing property on the display unit 6, and also displays the waveforms of the 1f signal and the 2f signal obtained in S2 and S4.

[0034] According to the above-described embodiment, parameter V2 is a value that depends on the gas concentration of the target gas and the received light power. Parameter V1 is a value that is not affected by the gas concentration of the target gas and that depends only on the received light power. Since parameter V2 / parameter V1 is a value that is not dependent on the received light power, the hermeticity of the sealed container 10 can be inspected with high accuracy. Specifically, even if there is a difference in the insertion loss of the sealed container 10 or a fluctuation in the output power of the laser light LL, this does not affect the inspection results.

[0035] The present invention is not limited to the above-described embodiments, and can be appropriately modified, improved, etc. Furthermore, the material, shape, size, number, location, etc. of each component in the above-described embodiments are arbitrary and not limited as long as they can achieve the present invention.

[0036] In the above-described embodiment, the parameter V2 is calculated from the 2f signal, but this is not limiting. The parameter V2 may also be calculated from the peak height of the received light signal at the absorption wavelength λc. Therefore, the signal processing unit 5 may calculate the parameter V2 from the received light signal and inspect the hermeticity of the sealed container 10 based on the parameter V2 / parameter V1.

[0037] Furthermore, the signal processing unit 5 may obtain, as the parameter V2, the peak heights D and E appearing before and after the absorption wavelength λc of the 1f signal.

[0038] Furthermore, the 3f signal (a signal having a frequency component that is three times the frequency of the sine wave W2 in the received light signal) has a waveform that is obtained by inverting the waveform of the 1f signal shown in Fig. 4. Therefore, the signal processing unit 5 may obtain the parameter V2 from the heights of peaks that appear before and after the absorption wavelength λc.

[0039] Furthermore, the 4f signal component (a signal having a frequency component four times that of the sine wave W in the received light signal) has a waveform that is like the 2f signal waveform shown in Fig. 5 flipped upside down. Therefore, the signal processing unit 5 may obtain the parameter V2 from the peak height of the 4f signal at the absorption wavelength λc. That is, the signal processing unit 5 can obtain the parameter V2 based on the nf signal (= n-th harmonic frequency component (n is an integer equal to or greater than 2)).

[0040] In the above-described embodiment, the wavelength of the laser light LL is swept by a ramp wave, but the present invention is not limited to this.

[0041] Furthermore, in the above-described embodiment, the signal level B at the absorption wavelength λc of the 2f signal is used as parameter V2, but this is not limited to this. The signal level B at the absorption wavelength λc of the 2f signal also varies depending on the gas pressure, etc. Therefore, parameter V2 may be obtained based on the shape of the 2f signal. By obtaining parameter V2 based on the shape of the 2f signal, it is possible to inspect the hermeticity of the sealed container 10 while reducing the influence of the gas pressure, etc.

[0042] Furthermore, as mentioned above, "laser light LL is absorbed by the target gas at the absorption wavelength λc of the target gas, and the light-receiving signal output from the photodetector 3 decreases," but as shown in FIG. 6, the difference between the signal levels C and C' when there is / is not absorption is often very small. In such cases, it can be considered that the signal level C is essentially equal to the signal level C'. Therefore, the signal processing unit 5 may determine the signal level C or C' from the light-receiving signal and use this as the parameter V1. [Explanation of symbols]

[0043] 2 Laser generating unit 3 Photodetector (light receiving part) 5. Signal processing section (inspection section) 10 Sealed container LL laser light

Claims

1. a laser generating unit (2) that generates a laser beam (LL) that is irradiated from the outside of the sealed container (10) toward the sealed container; a light receiving unit (3) that receives the laser light after passing through the head space of the sealed container; and an inspection unit (5) that inspects the hermeticity of the sealed container based on the light receiving signal of the light receiving unit. In the inspection device (1), the laser generating unit generates the frequency-modulated laser light, The inspection unit determines a first parameter based on the light receiving signal or a frequency component of a fundamental wave of the modulation frequency of the laser light detected from the light receiving signal, and determines a frequency component of an n-th multiple wave (n is an integer greater than or equal to 1) of the modulation frequency of the laser light detected from the light receiving signal. and determining a second parameter based on the first parameter and the second parameter, and inspecting the hermeticity of the sealed container based on the ratio of the first parameter to the second parameter. Inspection device (1).

2. 2. The inspection device according to claim 1, the inspection unit determines a first parameter based on a frequency component of a fundamental wave of the modulation frequency of the laser light detected from the light receiving signal, determines a second parameter based on a frequency component of a double wave of the modulation frequency of the laser light detected from the light receiving signal, and inspects the hermeticity of the sealed container based on a ratio between the first parameter and the second parameter. Inspection equipment.

3. 2. The inspection device according to claim 1, the inspection unit determines a first parameter based on the light receiving signal, determines a second parameter based on a frequency component of a second harmonic of the modulation frequency of the laser light detected from the light receiving signal, and inspects the hermeticity of the sealed container based on a ratio between the first parameter and the second parameter. Inspection equipment.

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