Infrared receiving LEDs, also known as infrared photodiodes or infrared detectors, play a crucial role in modern electronic devices and communication systems. They are commonly used to receive infrared light signals and convert them into electrical signals, thereby supporting functions such as infrared remote control and data transmission. In this process, the frequency requirement of infrared receiving LED is particularly critical, which directly affects the performance and application range of the receiver.

1、 The basic working principle of infrared receiving LED

The working principle of infrared receiving LED is based on the photoelectric effect, that is, when infrared light is irradiated on the photodiode, the photon energy is absorbed by the semiconductor material, exciting electron hole pairs and generating photoelectric current. The magnitude of this photocurrent is directly proportional to the intensity of the incident light, so the intensity of infrared light can be detected by measuring the magnitude of the photocurrent.

2、 Frequency requirements for infrared receiving LED

1. Response frequency

The response frequency refers to the frequency range of infrared light signals that an infrared receiving LED can respond to. Due to the wide frequency range of infrared light signals, ranging from a few hertz to several hundred terahertz, the response frequency of infrared receiving LEDs also needs to cover this range. However, in practical applications, due to limitations such as cost and technology, the response frequency of infrared receiving LEDs is often limited to a narrow range.

For most infrared receiving LEDs, their response frequency is usually between tens of kilohertz and hundreds of megahertz. The frequency within this range is sufficient to meet the needs of most applications, such as infrared remote control, infrared data transmission, etc. However, in some special application scenarios, such as high-speed infrared communication, infrared imaging, etc., higher response frequency infrared receiving LEDs may be required.

2. Bandwidth

Bandwidth refers to the frequency range of signals that infrared receiving LEDs can process. In an ideal scenario, we would like infrared receiving LEDs to have infinite bandwidth to be able to process signals of any frequency. However, in practical applications, due to physical and technological limitations, the bandwidth of infrared receiving LEDs is often limited.

The size of the bandwidth directly affects the performance of the infrared receiving LED. If the bandwidth is too small, some high-frequency signals will not be received and processed correctly, resulting in signal distortion or loss. Therefore, when selecting infrared receiving LEDs, it is necessary to choose the appropriate bandwidth according to the needs of the actual application scenario.

3. Modulation frequency

Modulation frequency refers to the frequency at which the infrared light signal is modulated. In infrared communication, in order to improve the anti-interference ability and transmission distance of the signal, it is usually necessary to modulate the infrared light signal. There are many ways of modulation, such as pulse modulation, frequency modulation, phase modulation, etc. Different modulation methods correspond to different modulation frequencies.

For infrared receiving LEDs, they need to be able to correctly receive and demodulate these modulated infrared signals. Therefore, infrared receiving LEDs need to have a sufficient modulation frequency range to adapt to different modulation methods and application scenarios.

4. Stability

Stability refers to the ability of infrared receiving LEDs to maintain stable performance over long periods of operation. Due to the complex working environment of infrared receiving LEDs, such as temperature changes, lighting changes, electromagnetic interference, etc., infrared receiving LEDs need to have good stability to ensure normal operation in various environments.

3、 Methods to improve the frequency performance of infrared receiving LED

1. Choose high-performance materials

By selecting high-performance semiconductor materials such as silicon and germanium, the photoelectric conversion efficiency and response speed of infrared receiving LEDs can be improved, thereby enhancing their frequency performance.

2. Optimize circuit design

By optimizing circuit design, such as using low-noise amplifiers, filters, and other technical means, the signal-to-noise ratio and anti-interference ability of infrared receiving LEDs can be improved, thereby enhancing their frequency performance.

3. Improve packaging technology

By improving the packaging process, such as using transparent packaging materials and optimizing the packaging structure, the optical and thermal losses of infrared receiving LEDs can be reduced, thereby improving their frequency performance.

4、 Summary

The frequency requirements for infrared receiving LEDs are multifaceted, including response frequency, bandwidth, modulation frequency, and stability.