Infrared LEDs are semiconductor light sources that emit light beyond the visible spectrum. Because infrared (IR) light cannot normally be seen by the human eye, infrared LEDs are widely used in sensing, communication, illumination, imaging, industrial equipment, automotive systems, and photobiomodulation devices.

Unlike visible LEDs, infrared LEDs are designed to produce specific wavelengths of invisible light. Common infrared LED wavelengths range from approximately 700 nm to 1065 nm, with different wavelengths selected for different applications.

Understanding what infrared LEDs are used for can help engineers and product designers choose the right wavelength, package, power level, and optical configuration for their applications.

What Is an Infrared LED?

An infrared LED is a light-emitting diode designed to generate infrared radiation instead of visible light.

Infrared LEDs typically use semiconductor materials that convert electrical energy into infrared optical energy. The emitted wavelength depends on the semiconductor material and device design.

Common wavelength ranges include:

• 730–760 nm: Near-infrared applications and plant-lighting research

• 810–850 nm: Sensing, imaging, and photobiomodulation

• 880–940 nm: Remote controls, sensors, and machine vision

• 950–1050 nm: Specialized sensing and imaging

• 1064 nm: Advanced sensing, photobiomodulation, and optical applications

The appropriate wavelength depends on the transmission, absorption, detection, and penetration characteristics required by the application.

What Are Infrared LEDs Used For?

1. Remote Controls

One of the most common uses of infrared LEDs is remote-control communication.

TV remotes, air-conditioner controllers, audio equipment, and other consumer devices often use infrared LEDs to transmit coded signals to a receiver.

A typical infrared remote uses an LED operating around the 940 nm region. The LED rapidly switches on and off according to a communication protocol, allowing the receiver to identify the command.

This application requires:

• Stable infrared output

• Fast switching

• High reliability

• Suitable beam angle

• Low power consumption

2. Security Cameras and Night Vision

Infrared LEDs are widely used for nighttime illumination in security cameras.

Because infrared light is invisible to humans but can be detected by many camera sensors, IR LEDs can illuminate an area without producing visible white light.

Common applications include:

• CCTV cameras

• Home security cameras

• Warehouse surveillance

• Parking-lot monitoring

• Industrial security systems

• Wildlife cameras

850 nm and 940 nm are commonly used for camera illumination.

An 850 nm infrared LED generally produces stronger camera response but may show a faint red glow. A 940 nm LED is less visible to the human eye, making it useful when discreet illumination is important.

3. Machine Vision

Infrared LEDs are also used in industrial machine-vision systems.

Manufacturing equipment can use infrared illumination to inspect components, detect defects, identify objects, and measure surface characteristics.

Infrared illumination can be useful when visible lighting creates unwanted reflections or when materials have different spectral responses in the infrared range.

Applications include:

• Automated optical inspection

• Barcode and code detection

• Object recognition

• Component inspection

• Quality control

• Industrial automation

The LED wavelength and optical distribution should be matched to the camera sensor and material being inspected.

4. Proximity and Distance Sensors

Infrared LEDs are frequently combined with photodiodes or other detectors to create optical sensing systems.

The LED emits infrared light, and the detector measures reflected or received light. Changes in the detected signal can then be used to determine whether an object is present or estimate its position.

Examples include:

• Proximity sensors

• Automatic faucets

• Smart appliances

• Robotics

• Industrial sensors

• Consumer electronics

These systems benefit from the relatively low cost, small size, and fast response of infrared LEDs.

5. Automotive Applications

Infrared LEDs are increasingly used in automotive sensing systems.

They can provide illumination for cameras and optical sensors used in areas such as:

• Driver monitoring

• Occupant monitoring

• Night vision

• Gesture detection

• Interior sensing

• Advanced driver-assistance systems

Infrared illumination is particularly useful for monitoring drivers and passengers because the system can collect optical information under low-light conditions without requiring bright visible illumination.

6. Optical Communication

Infrared LEDs can be used as optical transmitters for short-range communication systems.

The LED converts electrical information into modulated infrared light, which is then detected by a photodetector.

Although lasers are preferred for many high-speed and long-distance optical communication systems, LEDs can still be attractive for applications that require:

• Low cost

• Simple design

• Short transmission distances

• High reliability

7. Photobiomodulation and Light Therapy

Near-infrared LEDs are also used in photobiomodulation (PBM) and light-therapy devices.

Research has investigated wavelengths such as 810 nm, 830 nm, and 850 nm, among others, for biological applications.

Depending on the intended application, infrared or near-infrared light may be incorporated into:

• Light-therapy panels

• Wearable devices

• Skin-care equipment

• Recovery devices

• Clinical photobiomodulation equipment

For these systems, wavelength alone is not enough to define performance. Irradiance, energy density, exposure time, treatment distance, thermal management, and optical uniformity are also important.

8. Medical and Healthcare Equipment

Infrared LEDs can be incorporated into healthcare and diagnostic equipment for sensing and optical illumination.

Possible applications include:

• Optical monitoring

• Non-contact sensing

• Diagnostic instruments

• Phototherapy systems

• Wearable monitoring devices

Different wavelengths interact differently with biological tissue and optical detectors, so the LED must be selected according to the specific device design and intended measurement.

9. Agricultural and Horticultural Lighting

Certain near-infrared wavelengths are also being studied and used in specialized horticultural lighting systems.

Infrared and far-red light can influence plant photomorphogenic responses, particularly when combined with visible wavelengths such as red and blue.

LED manufacturers serving horticultural applications may develop systems combining multiple wavelengths to create customized spectral solutions.

For plant applications, the selection of infrared or far-red wavelengths should be based on the crop, growth stage, photobiological objective, and overall spectrum rather than using infrared output alone.

10. Infrared Heating and Industrial Applications

Infrared radiation can transfer energy to materials, and high-power infrared emitters can therefore be used in some heating and industrial processes.

Applications may include:

• Material drying

• Curing

• Heating

• Processing equipment

• Laboratory equipment

• Specialized industrial illumination

These applications often require higher optical power and careful thermal management compared with conventional low-power sensing LEDs.

Infrared LED vs. Visible LED

The biggest difference is the wavelength of emitted light.

A visible LED produces light that the human eye can see, while an infrared LED operates outside the visible spectrum.

Why Is Wavelength Important?

Infrared LEDs are not interchangeable simply because they are all “infrared.”

For example, 850 nm and 940 nm LEDs can behave differently in camera and sensing applications. Similarly, longer wavelengths can have different transmission and absorption characteristics.

Engineers should consider:

Wavelength: Determines how the light interacts with the target material or sensor.

Optical power: Determines how much infrared radiation is delivered to the application.

Beam angle: Determines how the emitted light is distributed.

Package size: Affects PCB layout, optical design, and thermal performance.

Thermal performance: Particularly important for high-power infrared LEDs.

Reliability: Critical for products operating continuously or in demanding environments.

How to Choose the Right Infrared LED

When selecting an infrared LED, start with the application rather than the LED package.

For a remote control, switching speed, wavelength, and low power consumption may be the key factors.

For a security camera, wavelength, radiant intensity, viewing angle, and camera sensitivity are more important.

For a photobiomodulation product, wavelength, optical output, treatment area, thermal performance, and dose control become especially important.

For industrial machine vision, spectral response, uniform illumination, reliability, and optical consistency may be the priorities.

Infrared LEDs are used in many technologies that require invisible optical radiation. Major applications include remote controls, security cameras, night vision, machine vision, sensors, automotive systems, optical communication, photobiomodulation, healthcare equipment, and specialized horticultural systems.

Common infrared LED wavelengths include 810 nm, 830 nm, 850 nm, 880 nm, 940 nm, 980 nm, and 1064 nm, although the most suitable wavelength depends on the specific application.

For LED manufacturers and OEM/ODM developers, the best infrared solution is not simply the highest-power LED. The right combination of wavelength, package, optical output, beam angle, thermal management, and reliability is what determines whether an infrared LED can deliver consistent performance in the final product.