Understanding LED Types and Their Unique Production Methods – Part II

Hi, everyone. I am back with part two of my article about LED types and how they are made. In Part I, I have discussed various types of LEDs (Light Emitting Diodes) and the distinct manufacturing processes. Also, I have explained how different LEDs are produced, highlighting the technological advancements and specialized techniques involved. Indeed, the first part showed LED tech in a simple way. This made us ready to study LED types and their uses more closely later.

SMD LED

Structure

SMD stands for Surface-Mount Device. SMD LEDs use a rectangular shape and sit directly on the surface of a printed circuit board (PCB). This design does not use wire leads like traditional LEDs. Instead, the SMD attaches to the PCB using small metal contacts. The internal parts include the LED chip, a phosphor layer, a lens, bond wires, and a heat sink. These parts are sealed in epoxy or silicone resin for protection.

• SMD LEDs use surface-mount technology (SMT). This allows for compact and flexible designs.
• The PCB gives mechanical support and helps with heat management.
• Bond wires connect the LED chip to the circuit.
• The heat sink pulls heat away from the chip, which helps the LED last longer.
• SMD LEDs can include three color chips in one unit, which allows for color mixing.

Compared to other types, SMD LEDs are smaller and more efficient. They allow for higher component density on the PCB. This makes them popular in many modern lighting and display applications.

Manufacturing

Machine Printing

Manufacturers use automated machines to place SMD LEDs on PCBs. At first, pick-and-place machines pick up each SMD and set it in the right spot. In fact, this process is fast and accurate. After that, the board goes through a reflow oven. Then, the oven melts solder paste, which bonds the SMD to the PCB. Thus, this method supports high-volume production and reduces errors.

PCB Board

The PCB is a key part of SMD LED manufacturing. It holds the SMDs and connects them with copper traces. The PCB also helps manage heat. Double-sided PCBs allow more SMDs in a small space. Additionally, this increases the brightness and flexibility of the final product. In fact, the PCB design impacts the durability and performance of the SMD LED.

Cost Factors

SMD LED manufacturing uses automated steps, which lowers labor costs. The process supports large-scale production, making SMD LEDs affordable. However, the circuit design is more complex than traditional LEDs. More solder points can mean more places for failure, which may raise maintenance costs. Still, the overall cost per unit stays low due to automation and high output.

Advantages

SMD LEDs offer many benefits:

• They use less electricity than older lighting types, which saves energy.
• SMD LEDs convert more power into light, not heat. This means less wasted energy.
• The average lifespan ranges from 50,000 to 65,000 hours.
• Good heat dissipation from the PCB and resin helps them last longer.
• SMD LEDs allow for flexible designs and color mixing.
• They fit many applications, from home lighting to electronics and cars.

SMD LEDs support modern lighting needs with their small size, energy savings, and long life.

Disadvantages

SMD LEDs offer many benefits, but they also present some disadvantages. One main issue is heat management. SMD LEDs can generate significant heat during operation. If the printed circuit board (PCB) does not remove heat well, the LED may fail early. This problem can limit the use of SMD LEDs in high-power lighting.

Another disadvantage is the complexity of repair. SMD LEDs use surface-mount technology (SMT), which means the components are very small. Repairing or replacing a single SMD LED on a PCB requires special tools and skills. This makes maintenance harder compared to traditional LEDs with wire leads.

SMD LEDs also face challenges with mechanical strength. The small size and surface mounting make them more sensitive to vibration and shock. If the PCB bends or flexes, the solder joints can crack. This can cause the SMD LED to stop working.

Color consistency can be another issue. When manufacturers produce large batches of SMD LEDs, slight differences in materials or process can cause color shifts. This can affect the appearance of lighting in some applications, such as displays or decorative lights.

Finally, SMD LEDs may have a higher initial cost than older LED types. The advanced manufacturing process and need for precise equipment add to the price. However, the long lifespan and energy savings often balance out the higher upfront cost.

Note: SMD LEDs need careful design and skilled handling to avoid these disadvantages.

Applications

SMD LEDs appear in many applications because of their small size and high efficiency. One common use is in display screens. Televisions, computer monitors, and digital billboards use SMD LEDs to create bright, colorful images. Certainly, the ability to mix colors in a single SMD LED allows for sharp and vivid displays.

Another important application is general lighting. SMD LEDs power many types of light bulbs, panel lights, and downlights. Their energy efficiency and long life make them a popular choice for homes, offices, and factories.

Automotive lighting also uses SMD LEDs. Car headlights, tail lights, and interior lights benefit from the compact size and durability of SMD LEDs. The technology allows for creative designs and better visibility.

SMD LEDs also play a role in portable electronics. Flashlights, smartphones, and wearable devices use SMD LEDs for backlighting and indicators. The small size fits well in slim and lightweight products.

COB LED

Structure

COB stands for Chip-on-Board. This technology uses many LED chips mounted directly onto a single substrate. Eventually, the chips form a uniform light source. The substrate supports the chips and helps manage heat. Actually, COB LEDs do not use brackets or extra packaging. The chips sit close together, which creates a smooth and bright light. Correspondingly, this design reduces glare and hotspots.

Manufacturing

Substrate

COB LED manufacturing starts with substrate preparation. At first, the substrate is often ceramic or metal-core PCB. Basically, it supports the chips and helps with heat dissipation. After that, workers clean and inspect the substrate to ensure quality. Eventually, a clean surface improves chip adhesion and performance.

Multiple Chips

Firstly, technicians sort LED chips by brightness and color. Then they place many chips on the substrate using robotic machines. Each chip sits close to the others, forming a panel-like light source. At the end, wire bonding or flip-chip bonding connects the chips to the circuit. This step improves electrical and thermal connections.

Heat Dissipation

COB LEDs use direct chip-to-substrate attachment. This design creates a low thermal resistance path. Heat moves quickly from the chips to the substrate and then to the heat sink. Encapsulation with silicone or epoxy protects the chips and helps with heat management. Good heat dissipation keeps the LED cool and extends its life.

Tip: COB LEDs work well in high-power lighting because of their strong heat management.

Advantages

COB LEDs offer several advantages:

• High luminous efficacy. They convert more electrical energy into light and waste less as heat.
• Enhanced thermal management. The compact design and advanced materials help remove heat quickly.
• Greater energy savings. Higher efficiency means lower operating costs.
• Longer lifespan. Good heat dissipation reduces stress on the chips.
• Uniform light output. The design creates a smooth, glare-free light with a wide viewing angle.
• Lower cost. The simplified manufacturing process reduces production expenses.

COB LEDs suit many applications, such as general lighting, retail, and automotive uses. In the long run, their reliable performance and energy savings make them a popular choice.

Disadvantages

COB LEDs offer many benefits, but they also present some challenges. One main disadvantage is heat concentration. Because many chips sit close together, heat builds up quickly. If the heat is not managed well, the LED can fail early. This makes strong heat sinks and good design very important for COB products.

Another issue is repair difficulty. When a single chip fails in a COB module, replacing it is hard. The chips are mounted directly on the board. Technicians often need to replace the whole module instead of just one chip. This increases maintenance costs.

COB LEDs also have limited color mixing. Most COB modules use chips of the same color. This design creates a smooth light, but it does not allow for easy color changes. SMD LEDs can mix colors better because they use separate chips for red, green, and blue.

The size of COB modules can also limit their use. Some lighting fixtures need small or flexible light sources. COB modules are larger and less flexible than SMD types. This makes them less suitable for some designs.

Light control is another challenge. COB LEDs produce a wide, even light. This is good for general lighting, but not for focused beams. Some applications need narrow beams or spotlights. COB modules may not fit these needs without extra optics.

Note: COB LEDs need careful design and strong heat management to avoid early failure.

Applications

COB LEDs work well in many lighting applications. Their strong light output and smooth beam make them a top choice for general lighting. Many homes and offices use COB modules in ceiling lights and downlights. The even light helps reduce shadows and glare.

Retail stores use COB LEDs to highlight products. The bright, uniform light makes items look clear and attractive. Museums and galleries also use COB modules to light artwork. The smooth beam protects art from harsh spots.

Street lights and floodlights often use COB technology. The high power and good heat management help these lights last longer outdoors. Car headlights and bike lights also use COB modules. The strong, wide beam improves safety at night.

Grow lights for plants use COB LEDs. The high efficiency and strong output help plants grow indoors. Some stage lights and studio lights use COB modules for their smooth, bright light.

COB LEDs fit many applications that need strong, even light. Their design works best where color mixing and small size are not needed.

MCOB LED

Structure

MCOB stands for Multi-Chip-On-Board. This technology uses many microchips on a single board. Each microchip is a tiny light source. The chips sit close together. This design creates a strong and even light. MCOB LED modules look like a flat panel. The chips connect to the board with advanced methods. The board helps with heat removal and supports the chips. MCOB LED modules are thin and light. They work well in many applications.

Manufacturing

Multi-Chip Arrangement

MCOB LED manufacturing uses a special arrangement. At first, workers place many microchips on one board. Each chip is less than 50 microns wide. This small size makes connection hard. To solve this, manufacturers use MiP (Micro LED-in-Package) technology. Lastly, MiP puts microchips into larger units. This step makes handling and connecting easier. MiP also helps sort and reject bad chips. The process improves yield and lowers failure rates.

Substrate

The substrate is the base for the chips. It can be glass, ceramic, or metal. The substrate must be very precise. Traditional printed circuit boards (PCBs) do not work for microchips. Manufacturers use fan-out packaging. Actually, this method makes the chip size bigger. Also, it helps connect chips to the substrate. The substrate also removes heat from the chips. Good heat management keeps the LED working longer.

Packaging

Packaging protects the chips and makes the module easy to use. MiP packaging allows direct surface mounting. This step helps with mass production. The packaging also supports sealing and injection designs. These features improve reliability. For very small MiP units, manufacturers use COB (Chip-On-Board) integration. This step combines mature mass transfer and COB processes. The packaging keeps the module safe from water, dust, and shock.

Advantages

MCOB LED modules offer many advantages over single-chip LEDs. They provide finer pixel pitch, which means clearer and sharper displays. The modules have ultra-wide viewing angles. This feature gives better visibility from different sides. Seamless splicing technology ensures smooth and uniform screens. The color accuracy is high, with sRGB at 100% and DCI-P3 at 97%. The contrast ratio reaches 10,000:1. Advanced chip-level packaging improves heat dissipation. This step increases reliability and lifespan. The modules are waterproof, dustproof, and resistant to shock and oxidation. Their compact and lightweight design allows flexible installation in many applications. A redundancy system keeps the module working in tough environments.

• MCOB LED modules use multiple chips for higher efficiency.
• Advanced packaging improves heat removal.
• The modules suit high-intensity applications needing large light sources.

Disadvantages

MCOB LEDs (Multi-Chip-On-Board Light Emitting Diodes) offer many benefits, but they also present some challenges. Heat management is a major concern. Many chips sit close together on the board. This design can cause heat to build up quickly. If the heat is not removed, the LED may fail early. Strong heat sinks and good design help, but the risk remains.

Repair and maintenance can be difficult. When one chip fails, technicians often need to replace the whole module. The chips are very small and close together. This makes it hard to fix just one chip. Maintenance costs can rise because of this issue.

Production cost is another disadvantage. MCOB LEDs use advanced packaging and precise placement. These steps require special machines and skilled workers. The cost to make each module is higher than for some other LED types. This can make MCOB LEDs less attractive for low-budget projects.

Color mixing is limited in most MCOB modules. The chips usually emit the same color. This design creates a smooth light, but it does not allow for easy color changes. SMD (Surface-Mount Device) LEDs can mix colors better because they use separate chips for red, green, and blue.

Mechanical strength can also be a problem. The thin and flat design makes the module more sensitive to bending or shock. If the board flexes, the chips or connections may break.

Note: MCOB LEDs need careful design and strong heat management to avoid early failure.

Applications

MCOB LEDs fit many modern lighting needs. Their high brightness and uniform light make them useful in large displays. Stadium screens and digital billboards often use MCOB modules. The even light helps create clear and bright images.

General lighting is another common use. Offices, shopping malls, and factories use MCOB LEDs in ceiling panels and downlights. The modules provide strong light and save energy. Their thin design allows for slim fixtures.

Automotive lighting benefits from MCOB technology. Car headlights and taillights use these modules for better visibility. The strong light output improves safety on the road.

Stage and studio lighting also use MCOB LEDs. The smooth and bright light helps create the right mood for performances. The modules work well in spotlights and floodlights.

Outdoor lighting uses MCOB LEDs in streetlights and floodlights. The modules handle harsh weather and last a long time. Their energy efficiency lowers operating costs for cities.

Specialty lighting includes plant grow lights and medical lamps. MCOB LEDs provide the high intensity needed for these tasks.

Tip: MCOB LEDs work best in places that need strong, even light and long life.

MCCOB LED

Structure

MCCOB stands for Multi-Color Chip-On-Board. Surprisingly, this technology uses several color chips on a single board. Eventually, each chip can emit a different color. Actually, the chips sit close together. This design creates a bright and even light. The board supports the chips and helps remove heat. MCCOB modules look like a flat panel. The chips connect to the board with advanced methods. Consequently, this structure allows for color mixing and smooth light output.

Manufacturing

Multi-Color Chips

At first, manufacturers select chips that emit red, green, and blue light. Then, they place these chips side by side on the board. This arrangement allows the module to produce many colors. Additioanally, the chips must match in brightness and wavelength. Thus, careful sorting ensures good color quality. Lastly, machines place the chips with high precision. Hence, this step is important for color consistency.

Substrate

The substrate is the base for the chips. It can be ceramic or metal. The substrate must be flat and clean. A good substrate helps remove heat from the chips. This keeps the module cool and working longer. The substrate also supports the electrical connections. Manufacturers use special coatings to protect the board from moisture and dust.

Packaging

Packaging protects the chips from damage. It also shapes the light output. Manufacturers use clear resin or silicone to cover the chips. This cover acts as a lens. It spreads the light evenly. The packaging must avoid bubbles and cracks. Bubbles can block light and reduce efficiency. The cover also helps with heat management. Good packaging keeps the module safe in many environments.

Advantages

MCCOB LED modules offer several benefits. Especially, they can produce many colors from one module. Additionally, the close chip arrangement gives smooth and bright light.In fact, the design allows for high brightness and wide viewing angles. Also, MCCOB modules use advanced packaging, which improves heat removal. Indeed, this step increases reliability and lifespan. The modules are thin and light. They fit well in displays and lighting panels. Thus, MCCOB technology supports creative lighting designs.

MCCOB LED modules work well in places that need strong, colorful, and even light.

Disadvantages

MCCOB LED (Multi-Color Chip-On-Board Light Emitting Diode) technology offers many benefits. However, it also presents some challenges. Users should consider these disadvantages before choosing MCCOB LEDs.

Heat management is a major concern. Many color chips sit close together on the board. This design can cause heat to build up quickly. If heat is not removed, the LED may fail early. Strong heat sinks and good design help, but the risk remains.

Repair and maintenance can be difficult. When one chip fails, technicians often need to replace the whole module. The chips are very small and close together. This makes it hard to fix just one chip. Maintenance costs can rise because of this issue.

Production cost is another disadvantage. MCCOB LEDs use advanced packaging and precise placement. These steps require special machines and skilled workers. The cost to make each module is higher than for some other LED types. This can make MCCOB LEDs less attractive for low-budget projects.

Color consistency can be a problem. Each chip must match in brightness and wavelength. Small differences in manufacturing can cause color shifts. This affects the appearance of lighting in displays or decorative lights.

Mechanical strength can also be a problem. The thin and flat design makes the module more sensitive to bending or shock. If the board flexes, the chips or connections may break.

Closing Remarks

I hope you have enjoyed this article from my series “How It Is Made”, specifically written for teens to spark their curiosity. In fact, teens can explore this and various other options of “How It Is Made” to plan their university level education and career thereafter. Please do leave a comment in the comment box or write to me personally about your feedback or questions, if any.

References

Seo, S. J., Park, S., & Jang, H. W. (2025). Flexible Micro-LEDs: advanced fabrication techniques and applications. Electronic Materials Letters. https://doi.org/10.1007/s13391-025-00559-7

R, G. A., S, C., & D, S. T. (2018). Open Source Automated SMD pick and place machine. Procedia Computer Science, 133, 872–878. https://doi.org/10.1016/j.procs.2018.07.107

Unión-Sánchez, J. d. D., Hermoso-Orzáez, M. J., Hervás-Pulido, M. J., & Ogáyar-Fernández, B. (2022). Impact of Thermal Dissipation on the Lighting Performance and Useful Life of LED Luminaires Applied to Urban Lighting: A Case Study. International Journal of Environmental Research and Public Health, 19(2), 752. https://doi.org/10.3390/ijerph19020752