A laser tube testing apparatus
By controlling the stepped voltage output of the module and comparing it with the CIV curve, the automatic detection of laser tubes is realized, which solves the problems of low detection efficiency and insufficient accuracy in the existing technology, and improves the intelligence and accuracy of laser tube detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENZHEN ADAPS PHOTONICS TECH CO LTD
- Filing Date
- 2025-07-09
- Publication Date
- 2026-07-07
AI Technical Summary
Existing laser testing methods lack automation and cannot accurately obtain initial conduction voltage and current values, resulting in the failure to screen out defective products with poor connections or electrostatic damage. The testing efficiency is low and easily affected by human factors.
The output voltage is increased in a stepwise manner using a control module. The emission current and optical power changes of the laser tube are obtained through the LD detection module and PD detection module. The laser tube fault is identified by comparing the CIV curve, thus realizing automated detection.
It improves the intelligence and accuracy of laser tube detection, enabling precise identification of conduction voltage and current, screening out samples with poor connections or electrostatic damage, and improving detection efficiency and accuracy.
Smart Images
Figure CN224471239U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of laser testing technology, and in particular to a laser tube testing device. Background Technology
[0002] In the field of laser packaging, traditional testing methods mainly rely on constant voltage and constant current power supplies, using optical power meters to measure the laser's optical power to evaluate its performance. While this method can basically determine whether a laser meets the predetermined optical power standard, it relies on human judgment for acceptance, lacks an automated testing process, has low testing efficiency, and is easily affected by human factors. Furthermore, relying solely on optical power meters to test the laser's optical power cannot accurately obtain the laser's initial on-voltage and the voltage and current values at different optical powers, failing to comprehensively reflect the individual performance of the laser.
[0003] Existing testing methods often fail to detect samples where the laser connection to the circuit board is weak or where electrostatic discharge causes excessive operating voltage. These defective samples are prone to insufficient power supply to the laser tube as the laser tube ages, or as the connecting wires and conductive adhesive age, posing a risk of functional failure. Therefore, traditional testing methods cannot effectively screen out these poorly connected samples, causing these potential problems to gradually emerge during subsequent use. Utility Model Content
[0004] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a laser tube testing device to solve the problems of low reliability and lack of automation in the existing testing methods.
[0005] To solve the above technical problems, the present invention adopts the following technical solution:
[0006] A laser tube testing device includes a control module, an LD detection module, a PD detection tube, and a PD detection module. The control module increases the output voltage in a stepped manner, which drives the laser tube under test to emit laser light through the LD detection module. The LD detection module obtains the emission current of the laser tube under test. The PD detection tube detects the laser light, and the PD detection module obtains the detection current of the PD detection tube. The control module identifies the change in optical power of the PD detection tube based on the detection current and determines whether the laser tube under test is faulty.
[0007] In the laser tube testing equipment, the LD detection module includes a current detection unit and a driving unit. The control module outputs a stepped increase in driving voltage, which is amplified by the driving unit to drive the laser tube under test to emit laser light. The current detection unit acquires the emission current of the laser tube under test and feeds it back to the control module.
[0008] The laser tube testing equipment also includes a laser tube holder for mounting the laser tube under test, the laser tube holder being located on the opposite side of the PD test tube.
[0009] In the laser tube testing equipment, the LD detection module includes a current power chip, a first resistor, and a first capacitor. The ALERT, SDA, and SCL pins of the current power chip are connected to the control module. The IN+ and VBUS pins of the current power chip are connected to the driving unit and are also connected to the positive terminal of the laser tube under test and the IN- pin of the current power chip through the first resistor. The first capacitor is connected in parallel with the first resistor.
[0010] In the laser tube testing equipment, the driving unit includes an operational amplifier, a MOS transistor, and a second resistor. The non-inverting input of the operational amplifier is connected to the control module, the output of the operational amplifier is connected to the inverting input of the operational amplifier and the source of the MOS transistor, the gate of the MOS transistor is connected to the control module, and the drain of the MOS transistor is connected to one end of the first resistor, the IN+ pin of the current power chip, and the VBUS pin.
[0011] In the laser tube testing equipment, the ALERT, SDA, and SCL pins of the current power chip are respectively connected to the power supply terminal through a pull-up resistor, and the A1 and A0 pins of the current power chip are respectively grounded through a pull-down resistor.
[0012] In the laser tube testing equipment, the LD detection module includes a second capacitor. One end of the second capacitor is connected to the other end of the first resistor and the positive terminal of the laser tube under test, and the other end of the second capacitor is grounded.
[0013] In the laser tube testing equipment, the PD detection module and the current detection unit are the same.
[0014] In the laser tube testing equipment, a wire is provided between the laser tube under test and the laser tube socket.
[0015] The laser tube testing equipment also includes a communication module that communicates with a host computer, and the communication module is connected to the control module.
[0016] Compared to existing technologies, the laser tube testing equipment provided by this utility model automatically tests the conduction voltage and conduction current of the laser tube under test by increasing the output voltage in a stepwise manner through the control module, driving the laser tube under test to emit laser light through the LD detection module, and obtaining the emission current of the laser tube under test through the LD detection module. The laser light is detected by the PD detection tube, and the detection current of the PD detection tube is obtained by the PD detection module. Then, the control module identifies the change value of the optical power of the PD detection tube based on the detection current and determines whether the laser tube under test is faulty. This achieves the automatic testing of the conduction voltage and conduction current of the laser tube under test, improves the intelligence level of the testing device, and also greatly improves the testing accuracy and efficiency. Attached Figure Description
[0017] Figure 1 The structural block diagram of the laser tube testing equipment provided by this utility model.
[0018] Figure 2 Circuit diagrams of the LD detection module and PD detection module in the laser tube testing equipment provided by this utility model.
[0019] Figure 3 A schematic diagram of the CIV curve during testing of the laser tube testing equipment provided by this utility model.
[0020] Explanation of reference numerals in the attached figures
[0021] Laser tube testing equipment 1, control module 10, LD detection module 20, current detection unit 21, drive unit 22, laser tube under test D1, PD detection tube D2, PD detection module 30, laser tube socket 40, wire 50, communication module 60, host computer 70, current power chip U1, first resistor R1, first capacitor C1, pull-up resistor RL, pull-down resistor RX, second capacitor C2, operational amplifier A1, MOSFET Q1, second resistor R2 Detailed Implementation
[0022] The laser tube testing equipment provided by this utility model solves the problem that existing laser tube testing fixtures can only test that the laser tube is currently functioning normally, but cannot accurately grasp the laser tube's conduction voltage and conduction current, as well as the LD current and voltage values corresponding to a certain number of specific optical powers and other performance-related parameters. It also solves the problem that existing laser tube testing fixtures are not automated enough and test data cannot be automatically saved online.
[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0024] Please see Figure 1The laser tube testing device 1 provided by this utility model mainly includes a control module 10, an LD (Laser Diode) detection module 20, a PD (Photodiode) detection tube D2, and a PD detection module 30. The LD detection module 20 and the PD detection module 30 are connected to the control module 10. The PD detection tube D2 is used to acquire the laser emitted by the laser tube under test, D1. This utility model utilizes the control module 10 to output a stepped voltage to the laser tube, and the LD detection module 20 and the PD detection module 30 respectively acquire the emission current and optical power changes of the laser tube, thereby achieving comprehensive testing of the laser tube performance.
[0025] Specifically, the control module 10 increases the output voltage in a stepwise manner, driving the laser tube under test D1 to emit laser light through the LD detection module 20. The LD detection module 20 obtains the emission current of the laser tube under test D1. The PD detection tube D2 detects the laser light, and the PD detection module 30 obtains the detection current of the PD detection tube D2. The control module 10 identifies the change value of the optical power of the PD detection tube D2 based on the detection current and determines whether the laser tube under test D1 is faulty. This achieves comprehensive testing of the laser tube performance, improves the intelligence level of the testing device, and significantly improves the testing accuracy and efficiency.
[0026] The control module 10 is the core part of this test device. It is responsible for providing the LD detection module 20 with a stepped increase in output voltage, and can accurately control the voltage output. It also determines the working status of the laser tube D1 under test based on the signal fed back by the PD detection module 30.
[0027] The LD detection module 20 consists of a current detection unit 21 and a driving unit 22. The input terminal of the current detection unit 21 is connected to the control module 10, and the output terminal of the current detection unit 21 and the driving unit 22 are connected to the laser tube socket 40. The current detection unit 21 detects the emission current of the laser tube under test D1 in real time and feeds the data back to the control module 10. The driving unit 22 is responsible for amplifying the voltage signal output by the control module 10 to drive the laser tube under test to emit laser light.
[0028] When the control module 10 outputs a stepped increase in driving voltage, the driving voltage is amplified by the driving unit 22 and then drives the laser tube under test D1 to emit laser light. The current detection unit 21 obtains the emission current of the laser tube under test D1 and feeds it back to the control module 10.
[0029] The PD detection tube D2 is used to receive the laser emitted by the laser tube, and the PD detection module 30 obtains the change value of the laser's optical power by monitoring the current of the PD detection tube D2.
[0030] In practice, the control module 10 outputs a stepped voltage, which is applied to the positive terminal of the laser tube under test, D1. The laser tube under test, D1, is connected to the current detection unit 21 to sample the laser tube current. During testing, the output voltage of the control module 10 starts from 0V and gradually increases according to the set steps. This invention can set the current value PD_I1-PD_I10 of the PD detection tube D2 corresponding to the stepped optical power of 0, 10, 20, 30, 40, 50, 60, 70, 80, and 90mW output by the laser tube under test, and the corresponding current value can also be obtained through detection. When the PD sampling current is not 0, it can be determined that the laser tube under test, D1, is conducting. The control module 10 saves the current voltage value Vth and current value Ith of the laser tube under test, D1. The output voltage of the control module 10 continues to increase stepwise, recording and saving the voltage and current values of the laser tube under test, corresponding to the PD current of 0-90mW optical power, and generating the corresponding individual (i.e., the current laser tube under test, D1) CIV curve (Current-Voltage-Light Power Curve, a curve used to characterize the performance of semiconductor lasers). Figure 3 As shown, the LD (laser) current curve reflects the change of LD current in the laser tube as the laser tube voltage changes, and the LD power curve reflects the change of optical power in the laser tube as the voltage changes. When the CIV curve of the laser under test has a high degree of overlap, it indicates that the laser under test is qualified. Samples that exceed the limit curve (such as the overlap between the LD current curve and the stored standard LD current curve is less than 95%, or the overlap between the PD current curve and the stored standard PD current curve is less than 95%) are considered defective. This utility model can comprehensively reflect the performance of the laser tube, including the changes in conduction voltage, conduction current, and optical power, by comparing the generated CIV curve with the standard CIV curve, thereby effectively screening out samples with poor connection or electrostatic discharge leakage.
[0031] The control module gradually increases the output voltage in a stepped manner, starting from 0V and progressively increasing it. This allows for precise identification of the initial conduction voltage (Vth) of the laser tube under test. This gradual increase ensures accurate detection of the laser tube's conduction state at any voltage point, avoiding misjudgments caused by sudden voltage changes. Meanwhile, the current detection unit in the LD detection module continuously monitors the emitted current (Ith) of the laser tube under test and feeds it back to the control module. Once a non-zero current is detected, the laser tube is determined to be conducting. Simultaneously, the corresponding voltage and current values are recorded, enabling accurate identification of the laser tube's initial conduction conditions and preventing misjudgments due to loose connections or leakage.
[0032] Optionally, the laser tube testing device 1 of this utility model further includes a laser tube holder 40 for mounting the laser tube D1 under test. The laser tube holder 40 is located on the opposite side of the PD detection tube D2, that is, the laser tube holder 40 is positioned directly opposite the PD detection tube D2 so that the light emitted by the laser tube D1 under test can be detected by the PD detection tube D2 as much as possible, thereby improving the accuracy of the test.
[0033] Furthermore, a wire 50 is provided between the laser tube under test D1 and the laser tube holder 40. When the laser tube holder 40 is far away from the PD detection tube D2 or when the length of the laser tube under test D1 is different, the laser tube holder 40 needs to match the laser tube under test D1 with the longest length. The shorter laser tube under test D1 cannot be well aligned with the PD detection tube D2. This utility model increases the compatibility of the testing device by adding the wire 50 so that the position of the laser tube under test D1 when emitting light is not limited by the position of the laser tube holder 40.
[0034] Furthermore, the laser tube testing equipment 1 of this utility model also includes a communication module 60 that communicates with the host computer 70. The communication module 60 is connected to the control module 10 and can use USB 2.0 communication to transmit the test results of the control module 10 to the host computer 70 in real time, which is convenient for data analysis and recording. The host computer 70 can also further analyze the test results based on the recorded data, so as to accurately grasp the CIV curve of a single laser tube during the laser tube material inspection process, select boundary samples based on the test results, and prevent them from flowing into the client and causing quality accidents. Moreover, this utility model also uses a single-chip microcomputer to program and control the test process, and connects to the host computer 70 to save test data, which is convenient and intelligent, and also facilitates subsequent quality traceability.
[0035] Please see Figure 2 In the laser tube testing device 1 of this utility model, the control module 10 can be an STM32F microcontroller, such as the STM32F103 series or STM32F407 series. The LD detection module 20 includes a current power chip U1, a first resistor R1 and a first capacitor C1. The current power chip U1 can be an INA226AIDGSR current power meter, which can measure forward and reverse current and is suitable for high-side or low-side current measurement. It has a gain error of 0.1% and an offset error of 10μV, which can ensure the accuracy of the measurement results.
[0036] The ALERT, SDA, and SCL pins of the current power chip U1 are connected to the control module 10. The IN+ and VBUS pins of the current power chip U1 are connected to the drive unit 22 and are also connected to the positive terminal of the laser tube under test D1 and the IN- pin of the current power chip U1 through the first resistor R1. The first capacitor C1 is connected in parallel with the first resistor R1.
[0037] The first resistor R1 and the first capacitor C1 form an RC filter circuit, which can reduce high-frequency noise on the input side of the current power chip U1 and reduce errors caused by electromagnetic interference (EMI) or other noise sources.
[0038] The ALERT, SDA, and SCL pins of the current power chip U1 are each connected to the 3V3 power supply terminal via a pull-up resistor RL. The A1 and A0 pins of the current power chip U1 are each grounded via a pull-up resistor RX. The pull-up resistor RL prevents excessively high input voltage or current, thereby protecting the chip's safety.
[0039] The LD detection module 20 includes a second capacitor C2. One end of the second capacitor C2 is connected to the other end of the first resistor R1 and the positive terminal of the laser tube D1 under test, and the other end of the second capacitor C2 is grounded. The second capacitor C2 can serve as a power supply decoupling capacitor, which helps stabilize the power supply voltage, reduce noise and ripple on the power line, ensure a stable power supply to the chip, and also helps reduce high-frequency noise in the input signal, thereby improving the accuracy of current measurement.
[0040] The PD detection module 30 is identical to the current detection unit 21, meaning that the PD detection module 30 includes the same current power chip U1, first resistor R1, first capacitor C1, pull-up resistor RL, pull-down resistor RX, second capacitor C2, etc., ensuring consistency and accuracy in detection. The negative terminal of the PD detection tube D2 is connected to the +3V3 power supply terminal, and the positive terminal of the PD detection tube D2 is connected to the IN+ and VBUS pins of the current power chip. When the PD detection tube D2 receives light, it generates a corresponding electrical signal, causing the current power chip of the PD detection module 30 to detect the PD current and feed it back to the microcontroller.
[0041] Furthermore, the driving unit 22 includes an operational amplifier A1, a MOSFET Q1, and a second resistor R2. Operational amplifier A1 acts as a voltage follower to improve current driving capability. MOSFET Q1 is a P-channel MOSFET. When the microcontroller pin connected to the gate of MOSFET Q1 outputs a low level, MOSFET Q1 conducts, causing the laser tube D1 under test to emit laser light. Operational amplifier A1 in driving unit 22 primarily functions as a voltage follower to improve current driving capability, i.e., it increases the driving current. The second resistor R2 has a resistance of 100Ω and is connected in series between the source and gate of MOSFET Q1. The source of MOSFET Q1 is connected to pin 1 of interface P1 and the output terminal of operational amplifier A1.
[0042] When the gate of MOSFET Q1 is floating (i.e., there is no voltage output from the microcontroller pin connected to the gate of MOSFET Q1), and the source voltage of MOSFET Q1 is the 3.3V voltage output by operational amplifier A1, the second resistor R2 pulls the gate voltage of MOSFET Q1 up to a high level. At this time, MOSFET Q1 cannot conduct, and the laser tube cannot emit laser light. However, when the microcontroller pin connected to the gate of MOSFET Q1 outputs a low level (i.e., when the signal LASER_ON_OFF is low), the gate voltage of MOSFET Q1 is pulled down to 0V, and the source voltage of MOSFET Q1 is the 3.3V output by operational amplifier A1. At this time, MOSFET Q1 conducts, and the second resistor R2 bears the 3.3V voltage drop, allowing the laser tube to emit laser light.
[0043] The non-inverting input of the operational amplifier A1 is connected to the control module 10. The output of the operational amplifier A1 is connected to the inverting input of the operational amplifier A1 and the source of the MOS transistor Q1. The gate of the MOS transistor Q1 is connected to the control module 10. The drain of the MOS transistor Q1 is connected to one end of the first resistor R1, the IN+ pin and the VBUS pin of the current power chip U1.
[0044] When testing a single laser tube, the microcontroller first sets a voltage V1 and outputs a corresponding drive voltage signal from one of its PA pins (e.g., PA5). This signal is then passed through operational amplifier A1 to improve the current drive capability. Simultaneously, the microcontroller outputs a low-level signal from another PA pin (e.g., PA6) to turn on the MOSFET Q1, causing the laser tube under test to emit light. The current power chip U1 of the LD detection module 20 measures the emitted current of the laser tube D1 as LD_I1. At the same time, the PD detection tube D2 receives the light emitted by the laser tube D1, converts it into a current signal, and the current power chip U1 of the PD current detection module measures the PD current as PD_I1. The microcontroller then records the values of V1, LD_I1, and PD_I1.
[0045] Then, the microcontroller changes the output voltage V2-Vn, so that the current power chip U1 of the LD detection module 20 measures the emission current of the laser tube D1 under test as LD_I2-LD_In, and the current power chip U1 of the PD current detection module also measures the PD current as PD_I2-PD_In.
[0046] The microcontroller can pre-store a table of correspondences between PD_I2-PD_In and optical power values (i.e., one current corresponds to one optical power value) and a standard CIV curve. Therefore, the microcontroller can obtain the CIV curve during testing based on the recorded voltage, LD current, and PD current, and compare it with the pre-stored standard CIV curve. If the detected LD current curve has a high degree of overlap with the standard LD current curve (e.g., greater than 95% or other set values), and the detected PD current curve has a high degree of overlap with the standard PD current curve (e.g., greater than 95% or other set values), the test result is that the tested laser tube D1 is qualified. In this embodiment, the overlap between the LD current curve and the standard LD current curve, and the overlap between the PD current curve and the standard PD current curve, are automatically identified by the microcontroller, and an alarm is triggered by light or sound when the overlap is lower than the set value. Since the calculation of the overlap between the LD current curve and the standard LD current curve is a built-in function of the STM32F microcontroller, and its calculation method is existing technology, it is not a protected point of this utility model and will not be described in detail here. Furthermore, the identification of CIV curve overlap can also be accomplished through a host computer, and this utility model does not impose any limitations on this.
[0047] In summary, this invention automatically adjusts the voltage and records the corresponding PD current through the control module to obtain the optical power change value, thereby realizing the automatic testing of the conduction voltage and conduction current of the laser tube under test. This improves the intelligence level of the testing device and also significantly enhances the testing accuracy and efficiency.
[0048] Furthermore, by automatically recording the corresponding LD current and PD current, it is convenient to check whether there is a fault in the laser tube control circuit. The test data can also be uploaded to the host computer for statistical analysis.
[0049] It is understood that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of this utility model, and all such substitutions or changes should fall within the protection scope of the appended claims of this utility model.
Claims
1. A laser tube testing device, characterized in that, The system includes a control module, an LD detection module, a PD detection tube, and a PD detection module. The control module increases the output voltage in a stepped manner, which drives the laser tube under test to emit laser light through the LD detection module. The LD detection module obtains the emission current of the laser tube under test. The PD detection tube detects the laser light, and the PD detection module obtains the detection current of the PD detection tube. The control module identifies the change in optical power of the PD detection tube based on the detection current and determines whether the laser tube under test is faulty.
2. The laser tube testing equipment according to claim 1, characterized in that, The LD detection module includes a current detection unit and a driving unit. The control module outputs a step-by-step increasing driving voltage. After the driving unit amplifies the driving voltage, it drives the laser tube under test to emit laser light. The current detection unit obtains the emission current of the laser tube under test and feeds it back to the control module.
3. The laser tube testing equipment according to claim 2, characterized in that, It also includes a laser tube holder for mounting the laser tube under test, the laser tube holder being located on the opposite side of the PD detection tube.
4. The laser tube testing device according to claim 2, characterized in that, The current detection unit includes a current power chip, a first resistor, and a first capacitor. The ALERT, SDA, and SCL pins of the current power chip are connected to the control module. The IN+ and VBUS pins of the current power chip are connected to the driving unit and also connected to the positive terminal of the laser tube under test and the IN- pin of the current power chip through the first resistor. The first capacitor is connected in parallel with the first resistor.
5. The laser tube testing device according to claim 4, characterized in that, The driving unit includes an operational amplifier, a MOSFET, and a second resistor. The non-inverting input of the operational amplifier is connected to the control module, the output of the operational amplifier is connected to the inverting input of the operational amplifier and the source of the MOSFET, the gate of the MOSFET is connected to the control module, and the drain of the MOSFET is connected to one end of the first resistor, the IN+ pin of the current power chip, and the VBUS pin.
6. The laser tube testing device according to claim 4, characterized in that, The ALERT, SDA, and SCL pins of the current power chip are each connected to the power supply terminal through a pull-up resistor, and the A1 and A0 pins of the current power chip are each grounded through a pull-down resistor.
7. The laser tube testing device according to claim 4, characterized in that, The LD detection module includes a second capacitor, one end of which is connected to the other end of the first resistor and the positive terminal of the laser tube under test, and the other end of the second capacitor is grounded.
8. The laser tube testing device according to claim 4, 6, or 7, characterized in that, The PD detection module is the same as the current detection unit.
9. The laser tube testing device according to claim 3, characterized in that, A wire is provided between the laser tube under test and the laser tube socket.
10. The laser tube testing device according to claim 1, characterized in that, It also includes a communication module that communicates with a host computer, and the communication module is connected to the control module.