Device for testing dark current of photodiode

Abstract

The utility model discloses a photodiode dark current testing device, comprising an LED lamp, a light shield, a dual-channel power supply, a desk type universal meter, a one-chip microcomputer control board and a multi-channel test board, the light shield is covered on the multi-channel test board, the multi-channel test board is provided with PD sockets having the same number as the channels of the multi-channel test board, and the PD sockets are connected with the desk type universal meter. The PD socket is composed of a 4P socket and Y-shaped sockets arranged side by side. After the scheme is adopted, the efficiency is greatly improved through multi-channel testing, and the vertical pins can be automatically tested through the design of the Y-shaped socket.

Description

Technical Field

[0001] This utility model relates to the field of optoelectronics, specifically to the field of photodiode testing. Background Technology

[0002] Dark current in a photodiode (PD) refers to the current generated inside the photodiode under a specified reverse voltage in the absence of incident light. PD dark current testing is an important indicator for determining whether a diode device has broken down and whether there are problems with the wafer fabrication process.

[0003] Because dark current is measured in PA levels, requiring high precision, existing PD dark current testing methods involve manual testing one by one using a PA meter. The current method utilizes the 10MΩ internal resistance of the Agilent 34401, testing the device's internal resistance voltage. Dividing the voltage by the resistance yields the current, which is the dark current of the product. However, the existing testing equipment can only test one product at a time and cannot automate the process. It requires manual operation: pressing a switch to power on, measuring the current when light is emitted, covering the light-blocking plate, measuring the dark current, and manually recording the data. This is error-prone and inefficient. Furthermore, for PD TO46 products, the MINIPD pins have standard parallel pins and 90° vertical pins. The existing solution is more compatible with these different pin configurations. However, the 90° vertical pin is inconvenient to insert, and testing 90° vertical pin products involves direct contact between the two pins, resulting in unreliable contact. Utility Model Content

[0004] The purpose of this invention is to provide a high-efficiency PD dark current testing device for vertical pins.

[0005] To achieve the above objectives, this utility model provides a testing device for the dark current of a photodiode, comprising an LED lamp, a light shield, a dual-channel power supply, a benchtop multimeter, a microcontroller control board, and a multi-channel test board. The light shield covers the multi-channel test board, which has a PD socket with the same number of channels as the test board. The PD socket consists of a 4-pin socket and a Y-shaped socket arranged side by side. The LED lamp with the same number of channels as the test board is located on the top inner side of the light shield and faces the PD socket on the multi-channel test board.

[0006] The relays on the multi-channel switching board are connected to the multi-channel test board via gold fingers, and the microcontroller control board is connected to the relays on the multi-channel switching board via I / O ports.

[0007] By adopting the above solution, this utility model greatly improves efficiency through multi-channel testing. By designing a "Y"-shaped socket, the vertical pins can be automatically tested. Attached Figure Description

[0008] Figure 1This is a structural block diagram of the present utility model;

[0009] Figure 2 This is a schematic diagram of the multi-channel test plate and light shield structure of this utility model;

[0010] Figure 3 This is a schematic diagram of the 8-channel multi-channel test board of this utility model (not a physical object);

[0011] Figure 4 This is a schematic diagram of the socket and light shield structure of this utility model;

[0012] Figure 5 This is a schematic diagram of the socket structure of this utility model.

[0013] Label Explanation:

[0014] 1. Light shield; 2. Multi-channel test board; 21. 4P socket; 22. Y-shaped socket; 3. LED light;

[0015] 4. Photodiode; 41. Vertical pin; 42. Horizontal pin. Detailed Implementation

[0016] To explain in detail the technical content, structural features, objectives and effects of this utility model, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0017] Please see Figure 1 This utility model discloses a testing device for the dark current of a photodiode, comprising an LED lamp 3, a light shield 1, a dual-channel power supply (Dingyang), a benchtop multimeter (Aligent34401A), a microcontroller control board, a multi-channel switching board, and a multi-channel test board. The relays on the multi-channel switching board are connected to the multi-channel test board via gold fingers, and the microcontroller control board is connected to the relays on the multi-channel switching board via I / O ports.

[0018] like Figure 2 , 3 As shown, the multi-channel test board 2 has a total of 8*8=64 channels. The multi-channel test board 2 can be inserted under the inverted light shield 1 (such as a drawer structure). The inner surface of the light shield 1 is equipped with LEDs with the same number of channels as the multi-channel test board 2. Figure 4 , 5 As shown, the multi-channel test board 2 has 64 pairs of 4P sockets 21 (a standard product with four holes) arranged side by side, totaling 8*8 pairs, and Y-shaped sockets 22. The vertical pin 41 of the photodiode 4 is inserted into one hole of the 4P socket 21, and the horizontal pin 42 of the photodiode 4 is inserted between the Y-shaped contacts of the Y-shaped socket 22 to form a circuit connection. An LED is located directly above each PD product to increase brightness and facilitate testing of photocurrent.

[0019] This testing device can test 64 PD products at a time, and can be repeatedly and continuously tested by changing the multi-channel test board.

[0020] Each PD product consists of two pins, PD+ and PD-. A dual-channel power supply from Sigstar provides power to both the multi-channel test board and the multi-channel switching board via one channel, and applies a 5V reverse bias voltage to the PD via the other channel. Computer software controls a microcontroller board via a serial port. The microcontroller board, in turn, controls relays on the switching board via I / O ports to switch between different products. The relays are connected via gold fingers. First, the LEDs are turned on, and an Agilent 34401 is used to test the voltage flowing through them. Since the 34401 has an internal resistance of 10MΩ, the voltage is divided by the resistance to convert it into current, which is the product's light current. After testing 64 products, the LEDs are turned off to create a dark environment. The Agilent 34401 is then used to test the voltage again, which is the dark current. The difference between the two currents is used to determine if the product is functioning correctly. The principle behind this determination is as follows:

[0021] If no product is plugged into the socket, the light current will be relatively low, thus the socket is deemed unqualified.

[0022] Products with plug-in connectors but excessively high dark current will be deemed unqualified based on the dark current test result.

[0023] Products with plugs but open circuits are considered defective. If there is a photocurrent, the current will be relatively small, and the difference between the two currents will be unacceptable, thus the product is deemed unacceptable.

[0024] Products with plugs but short circuits are considered defective. If there is a photocurrent, the difference between the two currents will be unacceptable, and the product will be deemed unacceptable.

[0025] Based on the above criteria, unqualified products can be identified, and the test data for each product can be transmitted to the computer via the GPIB line. The software automatically determines whether the data is within the acceptable range, automatically records the three current values, and saves the data.

[0026] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent shape or structural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A device for testing the dark current of a photodiode, characterized in that: It consists of LED lights, a light shield, a dual-channel power supply, a benchtop multimeter, a microcontroller control board, and a multi-channel test board. The light shield covers the multi-channel test board, which has the same number of PD sockets as the test board's channels. The PD sockets consist of 4-pin sockets and "Y"-shaped sockets arranged side by side. The LED lights, with the same number of channels as the test board, are located on the top inside the light shield and face the PD sockets on the multi-channel test board.

2. The photodiode dark current testing device as described in claim 1, characterized in that: The relays on the multi-channel switching board are connected to the multi-channel test board via gold fingers, and the microcontroller control board is connected to the relays on the multi-channel switching board via I / O ports.

Images