SHINHOP laser

Compared to traditional ultrasonic sensors, laser displacement sensors excel in speed, accuracy, and application range. Even though the technology of laser displacement sensors is complex, it does not affect their promising application prospects. With the continuous development of electronic technology, their application range is also expanding, such as in laser welding, laser cutting, and other new energy manufacturing industries, achieving precise geometric measurements of displacement, thickness, vibration, distance, diameter, length/height, etc.
1. Principle of Laser Displacement Sensors
First, let me share a schematic diagram of the principle of laser displacement sensors. The basic principle used by laser displacement sensors is the optical triangulation method:
The semiconductor laser ① is focused on the measured object ⑥ by the lens ②. The reflected light is collected by the lens ③ and projected onto the CMOS array ④; the signal processor ⑤ calculates the position of the light spot on the array ④ using trigonometric functions to obtain the distance to the object.
According to the measurement principle, laser displacement sensors are divided into laser triangulation method and laser echo analysis method. The laser triangulation method is generally suitable for high-precision, short-distance measurements, while the laser echo analysis method is used for long-distance measurements. Below, the principles of laser triangulation and laser echo analysis are introduced separately.

1. Principle of Laser Displacement Sensors: Laser Triangulation Method
The laser emitter directs visible red laser light onto the surface of the measured object. The reflected laser light is received by the internal CCD linear camera through the receiver lens. Depending on the distance, the CCD linear camera can 'see' this light spot at different angles. Based on this angle and the known distance between the laser and the camera, the digital signal processor can calculate the distance between the sensor and the measured object.
At the same time, the beam is processed through analog and digital circuits at the position of the receiving element, and the corresponding output value is calculated through the microprocessor analysis, outputting standard data signals proportionally within the user-defined analog window. If using switch output, it will conduct within the set window and cut off outside the window. Additionally, the analog and switch outputs can be independently set for detection windows.
Laser displacement sensors using triangulation can achieve a maximum linearity of 1um, with a resolution reaching 0.1um. For example, the ZLDS100 type sensor can achieve 0.01% high resolution, 0.1% high linearity, and 9.4KHz high response, suitable for harsh environments.
2. Principle of Laser Displacement Sensors: Laser Echo Analysis Method
Laser displacement sensors use echo analysis principles to measure distance to achieve a certain level of accuracy. The internal structure of the sensor consists of a processor unit, echo processing unit, laser emitter, laser receiver, and other components. The laser displacement sensor emits one million laser pulses per second to the detection object and returns to the receiver. The processor calculates the time required for the laser pulse to encounter the detection object and return to the receiver, thus calculating the distance value. This output value is the average of thousands of measurement results, known as the pulse time measurement method. The laser echo analysis method is suitable for long-distance detection, but the measurement accuracy is lower than that of the laser triangulation method, with a maximum detection distance of 250m.

2. Application Description of the Principle of Laser Displacement Sensors
Laser displacement sensors are commonly used for measuring physical quantities such as length, distance, vibration, speed, and orientation, and can also be used for flaw detection and monitoring of atmospheric pollutants.
1. Size Measurement: Identification of the position of small parts; monitoring of whether there are parts on the conveyor belt; detection of material overlap and coverage; control of the position of robotic arms (tool center position); device status detection; detection of device position (through small holes); liquid level monitoring; thickness measurement; vibration analysis; collision test measurement; automotive-related tests, etc.
2. Thickness Measurement of Metal Sheets and Plates: Laser sensors measure the thickness of metal sheets (plates). Detecting changes in thickness can help identify wrinkles, small holes, or overlaps to prevent machine failures.
3. Measurement of Cylinder Tubes: Simultaneously measure angle, length, inner and outer diameter eccentricity, conicity, concentricity, and surface profile. 4. Length Measurement: Place the measured component on a conveyor belt at a designated position. The laser sensor detects the component and measures it simultaneously with the triggered laser scanner, ultimately obtaining the length of the component.
5. Uniformity Check: Place several laser sensors in a row in the inclined direction of the moving workpiece to measure the output of one sensor directly. Additionally, a software can be used to calculate the measurement value and read the results based on signals or data.
6. Inspection of Electronic Components: Use two laser scanners to place the measured component between them, and finally read the data through the sensor to detect the accuracy and integrity of the component's dimensions.
7. Filling Level Check on Production Lines: Laser sensors are integrated into the production of filled products. When the filled product passes the sensor, it can detect whether it is filled to capacity. The sensor can accurately identify whether the filled product is qualified and the quantity of products using the laser beam reflection surface extension program.
8. Sensor Measurement of Object Straightness: First, you need 2-3 laser displacement sensors for combined measurement. Then, install the three laser displacement sensors in a straight line parallel to the production line, and determine the spacing between the three laser displacement sensors based on the required measurement accuracy. Finally, you need to move the object in a direction parallel to the installation line of the laser displacement sensors. When the production line is parallel to the sensor installation line, the greater the distance difference measured by the three sensors, the worse the straightness of the object; the smaller the distance difference, the better the straightness. You can establish a straightness percentage based on the length of the object to be measured and the spacing between the three sensors, thus obtaining a quantifiable signal output to achieve the purpose of detecting the object's straightness.

3. Application of Laser Displacement Sensors in Laser Welding
Due to the influence of the flatness of the workpiece surface in laser welding, or the irregular structure of the workpiece itself (such as curved surfaces, circular shapes, or uneven surfaces), it will inevitably affect the distance of the laser focus, thereby affecting changes in the laser spot, energy, and other aspects, resulting in welding processes that do not meet the requirements. Therefore, in practical welding applications, automatic focusing technology is urgently needed by users, and the laser displacement sensor system is precisely used to solve this problem for users. It can not only be used to measure speed, vibration, and orientation but is also primarily used to measure length or height. It can be combined with other control mechanisms to achieve the issuance of detection and control commands, realizing coordinated control. Therefore, it is often applied in automatic focusing systems in laser welding!
In the production and manufacturing of new energy products, especially in the welding of automotive and power batteries, the use of laser automatic focusing systems for welding operations is even more important, improving the welding process level of battery products and enhancing the safety and quality of batteries during use.