The lighting industry has significantly transformed, with light-emitting diode (LED) technology emerging as a revolutionary force. LED lights offer numerous benefits over traditional solutions, including enhanced energy efficiency and longer lifespan. However, it is essential to protect them from environmental factors, such as moisture and chemicals, as well as mechanical and thermal stress shock and physical damage, that can degrade their performance over time. This is where LED encapsulants come into play.
Encapsulants are applied to the LED chip during the manufacturing process, providing a protective barrier that helps extend the lifespan of components. This blog provides an overview of the different types of LED encapsulants, benefits, and key applications.
Types of LED Encapsulants
Several types of encapsulants are available, each with its properties and uses. Some of the most commonly used types include:
1. Epoxy Resins
Epoxy resins are widely used as LED encapsulants due to their excellent adhesion properties and high transparency. They form a strong bond with the LED chip and other components, effectively protecting against moisture, dust, and chemicals. A key quality of epoxy resin systems is the ability to tailor the product to meet the specific requirements of the application. How epoxy resin encapsulants can enhance performance and longevity of LEDs is discussed below.
2. Silicone
A silicone encapsulant offers excellent thermal stability, making it suitable for LED systems exposed to extreme heat or harsh environmental conditions. It is also known for its high UV resistance, preventing yellowing or degradation of the material over time.
3. Polyurethane
This type of encapsulant is known for its mechanical strength and durability. It protects against abrasion, impact, and vibration, making it ideal for outdoor or rugged applications. In addition, polyurethane offers good adhesion to various substrates.
4. Acrylic
Acrylic encapsulants are best known for their optical clarity and light transmission properties. They provide a physical barrier to shield components against moisture and chemicals.
Epoxy encapsulants are preferred over silicone, acrylic, and polyurethane due to their superior mechanical strength, chemical resistance, temperature resistance, adhesion, electrical insulation, and dimensional stability. They offer robust protection and reliability for a wide range of applications.
How LED Encapsulants Enhance Longevity and Performance
Epoxy resin encapsulants play a critical role in the protection and performance of LEDs. The chemistry involves a focus on providing mechanical support, protection from environmental factors, and aiding in light transmission. Epoxy resins are thermosetting polymers that are known for excellent mechanical properties, strong adhesion to many types of substrates, good heat resistance, and excellent electrical properties. Below are some ways in which epoxy resin encapsulants contribute to the durability and efficiency of LED products through optical management, and environmental and mechanical protection:
Protection From Environmental Factors
Epoxy resin provides excellent protection for LED components. LED encapsulants create a barrier shielding the delicate LED components from environmental threats such as moisture, dust, chemicals, and other environmental factors. This helps maintain the LED properties over time, including mitigation of corrosion and degradation of the LED.
Enhanced Thermal Management
LEDs generate heat during operation, which can degrade performance and shorten lifespan. Epoxy resin encapsulants can help efficiently transfer heat from the LED chip, preventing overheating and ensuring optimal performance. To extend the lifespan and improve efficiency of the LED, the encapsulant must provide good thermal conductivity to dissipate heat effectively, and effective thermal management to prevent thermal shocks and electromigration (causing short-circuits, open-circuits, performance degradation or device failure.)
Improved Mechanical Stability
Epoxy resin encapsulants protect the LED components from mechanical stress and impact damage, ensuring they remain intact and operational for an extended period. Repeated cyclic stresses can cause significant loss of mechanical stability and toughness, causing delamination and decreased light output. Mechanical stability is particularly important for LED products in outdoor or industrial environments subjected to mechanical stress, vibration, shock, or impact, to ensure the longevity of the LED.
Maintaining Optical Clarity
The encapsulant should have high light transmittance to optimize the efficiency of the LED. Certain encapsulants help maintain the transparency of the LED lens or cover, ensuring that the light output remains consistent and free from distortions, cloudiness or haze over time. This contributes to the performance and visual appeal of products by preserving the brightness and color stability and accuracy of the LEDs.
Yellowness and Discoloring
Over time, exposure to ultraviolet light (UV) can yellow or discolor the encapsulant (photodegradation). LED degradation results in both reduced light output and color changes. In particular, discoloration due to UV exposure is a common issue with acrylic encapsulants. It is important to use a UV-stable product that significantly reduces UV degradation, to maintain optical clarity and prolong the performance and life of the LED. Modified epoxy resin encapsulants also can minimize thermal degradation that can play a role in yellowing.
Excellent Electrical Properties
Epoxy resin is known for its excellent electrical properties, providing reliable and durable protection for electronic components to enhance performance and extend their lifespan. A key quality is providing excellent electrical insulation and thereby protecting sensitive components from electrical influences and overstress, including electrical open-circuits and short-circuits.
Other Factors Relevant to the Design and Selection of LED Encapsulants
In the design and selection of LED encapsulants, there are other issues to consider, including:
- Adhesion to Various Substrates
- Curing Process, Time, Temperature and Conditions
- Regulatory Compliance Factors, such as RoHS compliance
- Packaging
- Cost Considerations
The chemistry of epoxy resin LED encapsulants may be optimized for specific applications and it is important to consider all requirements of a particular application, balancing important factors such as optical clarity, thermal management, mechanical strength, and resistance to environmental challenges, to optimize performance, reliability, and durability of the LED.
Key Applications of LED Encapsulants
Here are some key applications where LED encapsulants are commonly utilized:
- General lighting: common lighting applications in residential, commercial, and industrial settings
- Automotive: LED headlights, tail lights, and interior lighting
- Outdoor: streetlights, garden lights, floodlights, landscape lighting, architectural lighting, and street/bridge lighting
- Electronic displays: LED screens for TVs, computer monitors, smartphones, cameras, signs, digital lighting for billboards, and stadium lighting
- Signage and Indicators: LEDs in indicators, traffic lights and signage
- Medical Devices: LEDs in medical diagnostic equipment and surgical devices
- Industrial Applications:LEDs for emergency lighting and inspection systems
- Transportation: Vehicle, train, ship, and airplane lighting, and transportation equipment lighting
- Special Applications: Agricultural grow lights, UV cure lights, aquarium lighting, and elevator and appliance lighting
United Resin’s Signature LED Encapsulants
United Resin is a leading provider of epoxy resin systems and offers products designed specifically for LED encapsulation. All United Resin LED epoxy resin encapsulants are RoHS compliant. United Resin’s signature products include:
Crystal Clear Resin with 117 Hardener
This two-component unfilled epoxy system features low viscosity and exotherm, ensuring an overnight cure. It also offers excellent thermal shock resistance, low shrinkage, and chemical resistance. This model is suitable for various applications, including LED lighting, power supplies, magnetic components, marine sonar devices, and mass potting. Notably, its softer formulation facilitates cut-out replacement and re-pouring for repairs as needed in an LED system.
Crystal Clear Resin with 929 or 939 Hardener
This is another two-component unfilled epoxy system featuring low viscosity and impressive flow qualities. It exhibits excellent adhesion to ceramics and glass, and its high-purity formulation prevents yellowing upon exposure to light. When cured, the material achieves a toughened state that is not brittle, making it ideal for thin bond lines and permanent LED placement.
E-Cast F-28 with 601 Hardener
E-Cast F-28 with 601 Hardener is a two-component unfilled epoxy with medium viscosity and good flow qualities. This rigid room temperature cure has excellent adhesion to metals, plastics, and ceramics. This system is excellent for LED backing applications, potting and encapsulating, power supplies, magnetic components, marine solar devices, and mass potting and encapsulation applications that need tough, impact resistant casting.
E-Cast F-82 with 601 Hardener
E-Cast F-82 with 601 Hardener is a two-component unfilled epoxy with low viscosity and low exotherm with an overnight cure. It exhibits good thermal shock resistance, low shrinkage, and excellent chemical resistance. This system is excellent for LED backing applications, power supplies, magnetic components, marine solar devices, and mass potting and encapsulating applications that need tough, impact resistant casting.
Premium LED Encapsulation Solutions From United Resin
United Resin is committed to providing superior LED encapsulation solutions that meet the highest standards of quality, performance, and reliability. Our LED encapsulation products are engineered to meet the unique requirements of LED applications. They offer superior protection against environmental challenges while maintaining excellent optical and aesthetic properties. We also provide customized solutions that can accommodate your specific lighting needs.
Contact us today to learn more about our products and services! You can also request a quote now to get started.
The information presented in this Blog is intended for general background and informational purposes only and is not intended as advice pertaining to any product, application or process. We encourage you to contact us for information concerning your specific needs and requirements and to discover how United Resin may assist you.