Precision laser resistance adjustment machine equipment

Precision laser resistance adjustment machine equipment

This machine is a laser resistance adjustment device specially developed for devices such as sensors, precision resistors, and data acquisition cards that require high-precision signal output. It has the characteristics of high resistance adjustment accuracy, fast engraving speed, reliable performance, and high degree of automation.

Laser resistance adjustment machine, also known as laser cutting system, works by using an extremely thin laser beam to hit a resistor, and cutting the circuit by vaporizing and evaporating the resistor. The laser beam cuts the resistor according to the predetermined program of the computer, and changes the resistance value by changing the geometric shape of the resistor. As the laser cutting process progresses, the circuit output is measured in real-time to continuously approach the target resistance value. When the resistance reaches the target resistance value, the laser beam is turned off, achieving the laser resistance adjustment process.

1. Principle of Precision Laser Resistance Adjustment System and Adjustment Technology

Resistance adjustment is the process of positioning a focused coherent light onto a workpiece under the control of a microcomputer, causing the film layer of the workpiece to vaporize and cut off to achieve the specified parameters or resistance values. When adjusting the resistance, the local temperature rise causes the glass to melt, and the edge of the resistance groove in the gasification part is covered by the glass, which can fill the medium cut on the surface of the substrate.
The advanced laser tuning system utilizes a large number of LSI and VLSI circuits, replacing many hardware functions with most software operations. The core part is directly connected to the laser, beam positioning, step-by-step repetition, and measurement systems through hardware. The measurement system consists of a passive network using a combination of precision bridge and matrix.

The laser tuning system has multiple tuning functions, which can tune hybrid integrated circuits, thick film resistor networks, capacitor networks, ceramic based thin film integrated components, as well as the accuracy of D/A and A/D converters, the frequency of V/F converters, the zero frequency of active filters, and the offset voltage of operational amplifiers. It also has an IEEE488 interface, which can be used for data transmission with other testing equipment.
2. The laser tuning system mainly includes the following parts:
(1) Laser section
Using a stable imported laser, the minimum spot size for thick film tuning is 30 μ m, and the pulse repetition frequency is 500Hz to 100kHz.
(2) Beam positioning system
It is divided into linear motor type, open-loop and closed-loop galvanometer type, etc. Control the position, velocity, and acceleration of the beam in the X and Y directions. Shorten the beam positioning time and adjustment time, resulting in high work efficiency.
(3) Programmable attenuation system
Composed of multiple attenuators to control the output signal used for beam movement and entering the infrared camera after attenuation.
(4) Repair and adjust the setter
It is directly connected to the laser, beam locator, step and repeat station, and measurement system. It can change the Q frequency, etching size, and cutting adjustment direction through the program to determine the change in resistance without affecting accuracy. In addition, it also has an automatic calibration function, which can keep the adjustment setting stable during long-term operation.
5) Resistance and voltage measuring device
Using a combination of precision bridge and matrix to test passive networks, the resistance measurement accuracy can reach 0.01%, and the measurement time is less than 5ms. This design can prevent external interference, and due to the use of differential measurement, it automatically eliminates deviation and polarity conversion. It can also be used to measure the DC voltage during active circuit maintenance.
(6) Automatic power measurement system
Laser power measurement is determined through measurement with minimal interruption. The spiral tube drive system is controlled by a microcomputer, and the laser beam passes through the 100% reflector inside the attenuator, is directed towards the thermocouple device, and then sent to a multi range power meter.
Cutting graphics
When using laser resistance adjustment, the main types of resistor patterns to be cut are as follows:
(1) Single blade cutting resistance method
(2) Double blade cutting resistance method
(3) L-shaped blade cutting resistance method
(4) Cross cut resistance method
(5) Cutting method of curved L-shaped blade
(6) Cutting method of curved U-shaped blade
In practical work, the first four types are mainly used, and different knife edges should be selected according to the different square numbers of resistors. Among them, double cutting and L-shaped cutting edges are the most commonly used, and the adjusted resistance values have good stability.

4. Common resistance adjustment methods include sandblasting, laser, and voltage pulse adjustment:
Sandblasting resistance adjustment: By spraying sand flow to polish the resistance substrate, the resistance slurry layer is worn, thereby changing the conductive cross-sectional area and length of the resistance body to achieve a certain required resistance value. It is a conventional resistance adjustment scheme.
The price of sandblasting resistance adjustment machine equipment is relatively low, but the accuracy of resistance adjustment is difficult to control, the speed is slow, and it is not easy to automate and mass produce.
Laser resistance adjustment: By scanning and cutting the resistor substrate with a short pulse laser, the resistor paste layer is heated and vaporized by the laser, forming a certain depth of scratches, thereby changing the conductive cross-sectional area and length of the resistor body, achieving the adjustment of resistors below the target resistance value to the allowable deviation range of resistance value. It is suitable for rapid and large-scale production of sheet resistors.
Laser resistance adjustment machine has a high price, easy precision control, fast speed, and is easy to automate and mass produce. It can also complete the function of circuit resistance adjustment and is currently the mainstream process for resistance adjustment.
Laser precision machining will be increasingly applied in industrial fields such as functional fine-tuning of thin film circuits, fine-tuning of piezoelectric quartz resonators and single-layer filters, correction of photomasks, fine-tuning of ultra-high frequency circuits with distributed parameters, and engraving of optical dials and dividers.
The BZL-SL12A series of laser resistance adjustment machines are designed according to market requirements, and their functions and product designs can be customized according to customer circuit requirements.

５. Resistance Adjustment Scheme for Precision Laser Resistance Adjustment System

The advanced laser fine-tuning system (laser resistance adjustment equipment, laser resistance adjustment equipment) mainly includes the following parts:
(1) Laser section
Using imported fiber lasers, the minimum spot size for thick film tuning is 38 μ m, and the pulse repetition frequency is 500Hz to 100kHz.
(2) Beam positioning system
It is divided into linear motor type, open-loop and closed-loop galvanometer type, etc. Control the position, velocity, and acceleration of the beam in the X and Y directions. Shorten the beam positioning time and adjustment time, resulting in high work efficiency.
(3) Programmable attenuation system
Composed of multiple attenuators to control the output signal used for beam movement and entering the infrared camera after attenuation.
(4) Repair and adjust the setter
It is directly connected to the laser, beam locator, step and repeat station, and measurement system. It can change the Q frequency, etching size, and cutting adjustment direction through the program to determine the change in resistance without affecting accuracy. In addition, it also has an automatic calibration function, which can keep the adjustment setting stable during long-term operation.
5) Resistance and voltage measuring device
Using a combination of precision bridge and matrix to test passive networks, the resistance measurement accuracy can reach 0.01%, and the measurement time is only 25 µ s. This design can prevent external interference, and due to the use of differential measurement, it automatically eliminates deviation and polarity conversion. It can also be used to measure the DC voltage during active circuit maintenance.
(6) Automatic power measurement system
Laser power measurement is determined through measurement with minimal interruption. The spiral tube drive system is controlled by a microcomputer, and the laser beam passes through the 100% reflector inside the attenuator, is directed towards the thermocouple device, and then sent to a multi range power meter.
Simple resistance adjustment scheme:
6. Implementation function: By manually controlling the control needle, the electrical group can be automatically and precisely adjusted
1. Laser and control system: imported fiber laser
2. Optical positioning system: XY automatic control
3. Resistance measurement and control system
4. Manual needle control
7. Standard resistance adjustment scheme:
Implementation function: Through automatic control of the needle, precise adjustment of batch electric groups can be achieved automatically.
1. Laser and control system: imported fiber laser
2. Optical positioning system: Five dimensional working mode
3. Resistance measurement and control system
4. Automatic needle control: automatic up and down
5. Monitoring system: Dual channel 3-megapixel CCD monitoring
6. Online function resistance adjustment plan:

7. Types of laser resistance adjusters

At present, resistance regulators can be divided into simple resistance regulation and functional resistance regulation according to their functions:
Simple resistance adjustment:
Adjust the resistor to a fixed resistance value to complete the resistance adjustment. This type of device is relatively simple.
Functional impedance modulation:
Accurately adjust the resistance in a certain circuit to enable the circuit module to perform its corresponding function. This type of equipment is relatively complex and compatible with the circuit requirements

Main technical parameters