Detection method for optimizing after-vibration frequency and detection circuit used therefor

Abstract

This invention provides a detection method and detection circuit for optimizing after-vibration frequency. [Solution] The detection circuit used in the detection method for optimizing the aftershock frequency includes a drive circuit, an ultrasonic probe 1 to be detected, a signal processing device, two resistors 2a and 2b connected in parallel between the ultrasonic probe 1 and the signal processing device, a switch 3 connected to resistor 2b, and a microcontroller 5 that controls the switch 3. The detection method includes a first step of detecting the aftershock frequency, a second step of determining that the detection is acceptable and ending the detection if the frequency offset rate is smaller than a reference value, and turning off the switch 3 and increasing the resistance of the detection circuit if it is larger than the reference value, a third step of detecting the aftershock frequency again, and a fourth step of determining that the detection is acceptable and ending the detection if the frequency offset rate is smaller than a reference value if the re-detection is acceptable and ending the detection, and determining that the product is unacceptable and discarding the product if it is larger than the reference value.

Description

Technical Field

[0001] The present invention relates to a detection method, and particularly to a detection method for optimizing the after-vibration frequency and a detection circuit used therefor.

Background Art

[0002] With the rapid development of science and technology, the smart devices incorporated in automobiles have been increasing, and automobiles have come to have smart functions. However, in order to realize the terminals of these smart devices, sensors are ultimately required, and ultrasonic sensors are widely applied as products with mature and stabilized technology and high cost performance.

[0003] In the manufacturing process of ultrasonic sensors, in order to maximize the economic benefits of the factory, a process with high efficiency and excellent quality control is required. When an ultrasonic sensor operates, it emits ultrasonic waves due to the vibration of the sensor, and the vibrating sensor cannot immediately stop vibrating due to its own physical inertia, and it takes a certain amount of time until the vibration stops. This delay time is called after-vibration. In the manufacturing process, it is necessary to detect the after-vibration frequency of the sensor. When it is detected that the after-vibration frequency exceeds the reference value, there is no choice but to passively accept and discard the product. However, among these defective products, there are a considerable number that are discarded because there is no problem with the product itself, the main function of obstacle detection is sound, and for some reason, the after-vibration is insufficient and the detection result of the after-vibration frequency becomes abnormal, resulting in unnecessary waste.

[0004] In order to improve the yield, manufacturers have adopted the following two methods. One is a method of extending the after-vibration time and improving the non-conformance (NG) of the after-vibration frequency detection due to insufficient after-vibration time by changing the capacitance value or inductance value in the peripheral circuit, for example, in the matching circuit, to make the entire circuit in a frequency mismatch state. However, in this method, the after-vibration time of all sensors becomes longer, and furthermore, the non-detection zone of all sensors becomes larger.

[0005] Another approach involves modifying the internal design of the probe, a subcomponent of the ultrasonic sensor, for example, by changing the hardness or ratio of the internal adhesive. This extends the vibration time and improves the failure to detect vibration frequencies due to insufficient vibration time (NG). However, this method increases the vibration time for all sensors and also enlarges the undetectable zone for all sensors. Furthermore, the design, verification, and implementation cycle for such modifications becomes very long.

[0006] Therefore, it is necessary to improve the detection methods used by manufacturers to adapt them to aftershock detection at this stage, without affecting the structure and application of the sensor itself. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The technical problem that the present invention aims to solve is to provide a detection method for optimizing aftershock frequencies, which enables expansion of aftershock frequencies through circuit and software control, allowing an aftershock frequency detection module inside an application-specific integrated circuit (ASIC) to acquire a sufficient number of waveforms, thereby avoiding or reducing aftershock frequency detection failures due to insufficient waveforms, and also increases the sound pressure of sensors using low-Q (weak vibration) ultrasonic probes, lowers the requirements for reception gain, and improves the signal-to-noise ratio. [Means for solving the problem]

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is: A detection circuit used in a detection method for optimizing after-vibration frequency, comprising a drive circuit, the drive circuit being connected to an ultrasonic probe to be detected, the ultrasonic probe being externally connected to a signal processing device, two resistors being provided in parallel between the ultrasonic probe and the signal processing device, one of which resistors being connected to a microcontroller that controls a switch connected to the detection circuit, the detection method comprising a first step of detecting the after-vibration frequency and obtaining a detection result, and a second step of determining whether the frequency offset rate of the detection result is smaller than a reference value, and if it is smaller than the reference value, determining that it is a pass and terminating the detection, This detection circuit is used in a detection method for optimizing the aftershock frequency, which includes: a second step in which, if the wavenumber offset rate is greater than a reference value, the microcontroller switches off a switch, disconnects the connection to one of the two parallel-connected resistors, and increases the resistance in the detection circuit; a third step in which the aftershock frequency is detected again to obtain the result of secondary detection; and a fourth step in which the result and the reference value are compared to determine whether the frequency offset rate is smaller than the reference value, and if it is smaller than the reference value, it is determined to be a pass and the detection is terminated, and if the frequency offset rate is greater than the reference value, it is determined to be a fail and the product is discarded.

[0009] Furthermore, in the detection circuit, the two resistors connected in parallel may have the same resistance value, or they may have different resistance values.

[0010] Furthermore, the resistor connected to the microcontroller is replaced with a transistor.

[0011] Furthermore, the transistor is connected to an EEPROM (i.e., electrically-erasable programmable read-only memory).

[0012] Furthermore, both the signal processing unit and the microcontroller are integrated inside the detection chip.

[0013] Furthermore, both the EEPROM and the transistor are integrated inside the detection chip.

[0014] Furthermore, the detection reference values ​​are the reference values ​​for detecting ultrasonic after-vibrations according to each standard, and are used by manufacturers to determine whether or not an ultrasonic sensor passes the inspection. [Effects of the Invention]

[0015] Compared to conventional technology, the detection method for optimizing after-vibration frequency according to the present invention increases the impedance around the sensor by increasing the resistance in the detection circuit, thereby increasing the after-vibration and expanding the detection range to include after-vibrations that were originally undetectable. In this way, some sensors with weak probe vibrations can be detected again, improving manufacturing yield and increasing the economic benefits of companies. [Brief explanation of the drawing]

[0016] [Figure 1] A schematic flowchart of the detection method for optimizing after-vibration frequency according to the present invention is shown. [Figure 2] This diagram shows a detection circuit used in the detection method for optimizing the after-vibration frequency in Embodiment 1 of the present invention. [Figure 3] This diagram shows the detection circuit used in the detection method for optimizing the after-vibration frequency in Embodiment 2 of the present invention. [Figure 4] The detection results from experimental detection data of one group of the present invention are shown. [Modes for carrying out the invention]

[0017] To make the above-mentioned objectives, features, and characteristics of the present invention clearer and easier to understand, relevant embodiments of the present invention will be described in detail below with reference to the drawings.

[0018] In one embodiment, as shown in Figures 1 and 2, the detection circuit used in the detection method for optimizing the after-vibration frequency includes a drive circuit, the drive circuit is connected to an ultrasonic probe 1 to be detected, the ultrasonic probe 1 is externally connected to a signal processing device, and two first and second electronic elements are provided in parallel between the ultrasonic probe 1 and the signal processing device, the first electronic element being a first resistor 2a and the second electronic element being a second resistor 2b, the second electronic element (i.e., the second resistor 2b) is connected to a microcontroller 5 that controls a switch 3 connected to the detection circuit, and the detection method is as follows.

[0019] In the first step, the after-vibration frequency is detected and a detection result is obtained. In the second step, it is determined whether the frequency offset rate is smaller than a reference value (for example, the reference value is a frequency offset of 9.36%) based on the detection result. If it is smaller than the reference value, it is judged to pass and the detection is terminated. If the frequency offset rate is larger than the reference value, the microcontroller turns off switch 3, disconnecting the connection with one of the two parallel-connected resistors and increasing the resistance in the detection circuit. In the third step, the after-vibration frequency is detected again and a secondary detection result is obtained. In the fourth step, the result and the reference value are compared to determine whether the frequency offset rate is smaller than the reference value. If it is smaller than the reference value, it is judged to pass and the detection is terminated. If the frequency offset rate is larger than the reference value, it is judged to fail and the product is discarded.

[0020] In another embodiment, as shown in FIGS. 1 and 3, the detection circuit used in the detection method for optimizing the after-vibration frequency includes a drive circuit. The drive circuit is connected to the ultrasonic probe 1 to be detected. The ultrasonic probe 1 is externally connected to a signal processing device. A first electronic element and a second electronic element connected in parallel are provided between the ultrasonic probe 1 and the signal processing device. The first electronic element is a first resistor 2a, and the second electronic element is a transistor 6. The transistor 6 is connected to a microcontroller 5 that controls the on / off of the transistor 6 by an EEPROM 7 (i.e., Electrically-Erasable Programmable Read-Only Memory). Here, the transistor 6, the EEPROM 7, and the microcontroller 5 are all integrated inside the detection chip. The detection method is the same as that in Embodiment 1.

[0021] Specific experimental data are as follows. In one group, the resistors connected in parallel are 4.1 KΩ and 8.2 KΩ respectively, and the reference value of the detection result is a frequency offset of 9.36%. So, when the detection record number is "00", the result is 3.12% or less; when the number is "01", the result is 6.24% or less; when the number is "10", the result is 9.36% or less; when the number is "11", the result is greater than 9.36%.

[0022] To sum up, when the number 11 is shown on the detection chip, it is determined that the result is unqualified, and all other numbers indicate that the product is qualified. The detection results are as shown in FIG. 4.

[0023] The present invention realizes the extension of the after-vibration frequency through a circuit and software control, enabling the after-vibration frequency detection module inside an Application-Specific Integrated Circuit (ASIC) to acquire a sufficient number of waveforms, avoiding or reducing the failure of after-vibration frequency detection caused by insufficient waveform numbers, increasing the sound pressure of a sensor using an ultrasonic probe with a low Q value (weak vibration), reducing the requirement for the receiving gain, and improving the Signal-to-noise ratio, and provides a detection method for optimizing the after-vibration frequency.

[0024] Compared with the prior art, the detection method for optimizing the after-vibration frequency of the present invention increases the resistance in the detection circuit to raise the impedance around the sensor, increase the after-vibration, expand the detection range to detect the after-vibration that could not be detected originally, and thus redetect some sensors with weak probe vibrations, improve the manufacturing yield, and increase the economic benefits of the enterprise.

[0025] Finally, it should be noted that the above embodiments are only for explaining the technical solutions of the present invention and do not limit the technical solutions of the present invention. Those skilled in the art should understand that any modification or equivalent substitution added to the technical solutions of the present invention within the scope not departing from the gist and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Explanation of Signs

[0026] 1 Ultrasonic probe 2a First resistor 2b Second resistor 3 Switch 4 Switch control signal 5 Microcontroller 6 Transistor 7 EEPROM

Claims

1. A detection circuit used in a detection method for optimizing after-vibration frequency, the detection circuit includes a drive circuit, the drive circuit is connected to an ultrasonic probe to be detected, the ultrasonic probe is externally connected to a signal processing device, and two first and second electronic elements are provided in parallel between the ultrasonic probe and the signal processing device, the first electronic element being a first resistor, the second electronic element being a second resistor or a transistor, and the second electronic element being connected to a microcontroller that controls a switch connected to the detection circuit. The aforementioned detection method is The first step involves detecting the after-sound frequency and obtaining the detection result, The detection result is determined to determine whether the frequency offset rate is smaller than a reference value. If it is smaller than the reference value, it is judged as passing and the detection is terminated. If the frequency offset rate is larger than the reference value, the microcontroller switches off the switch, disconnects the connection to one of the two parallel-connected resistors, and increases the resistance in the detection circuit. (Second step) The third step involves detecting the after-vibration frequency again to obtain the results of the secondary detection, In the fourth step, the frequency offset rate is compared with the reference value based on the result. If it is smaller than the reference value, it is judged as passing and the detection is terminated. If the frequency offset rate is larger than the reference value, it is judged as failing and the product is discarded. A detection circuit used in a detection method for optimizing after-vibration frequencies, including those included in the after-vibration frequency.

2. A detection circuit used in a detection method for optimizing the after-vibration frequency according to claim 1, wherein the two first and second resistors connected in parallel are either resistors having the same resistance value or resistors having different resistance values.

3. The detection circuit used in the detection method for optimizing the after-vibration frequency according to claim 1, wherein the second resistor connected to the microcontroller is replaced with the transistor.

4. The transistor is connected to an EEPROM (i.e., an electrically erasable programmable read-only memory) and is used in a detection circuit for a detection method for optimizing the after-vibration frequency according to claim 3.

5. The aforementioned signal processing device and microcontroller are both integrated inside the detection chip, and the detection circuit is used in the detection method for optimizing the after-vibration frequency according to claim 1.

6. A detection circuit used in a detection method for optimizing the after-vibration frequency according to claim 4, wherein both the EEPROM and the transistor are integrated inside the detection chip.

7. A detection method for optimizing the aftershock frequency using the detection circuit described in claim 1, wherein the reference value for detection is the reference value for aftershock detection of ultrasonic waves according to each standard, and is used by the manufacturer to determine whether or not the ultrasonic sensor passes the test.

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