PCBs for the LED Lighting Industry

Printed circuit boards, or PCBs, are everywhere in our technology-based society. Everything from computers to medical equipment to cars contains PCBs in one form or another. However, PCBs are not all the same— each product is custom with different designs or materials and specifications to suit a unique purpose. The base material is essential for an LED circuit board, as it helps determine how effectively it transfers heat.

Some applications require specific properties in their circuit boards. This is especially true for temperature-sensitive applications, one of which is LED lighting. The LED lighting industry is expanding rapidly in response to increased interest in the more efficient and cost-effective lighting method, but much of the functionality of LED lights depends on the temperature of its system. For many companies, the solution to this problem is aluminum-based PCBs.

To help you understand why the LED lighting industry uses PCBs, we’ve outlined the nature of base layers, the benefits of aluminum circuit boards and why they work well in the LED lighting industry.

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LED PCB

An LED printed circuit board is used to mount the diode(s) and power the LED for the application. LED stands for light-emitting diode.

Generally, LED devices use a surface-mounted design (SMD) that includes a single LED component. To generate more light, an LED circuit board connects multiple lights.

Because these lights and their operation generate a large amount of heat, they need to have a way to remove this heat, such as a heat sink or structural material that draws away heat. Hence, the LED PCB material may be aluminum, which excels at transferring heat away from the board.

Due to the many advantages of LED lighting and its multiple applications in modern life, LED PCB manufacturing and products have increased to meet the rising demand.

The Benefits of LED Lighting

LED lighting is an increasingly popular lighting solution, favored for its improved longevity and reduced environmental impact. Some of the benefits of LED lighting over conventional methods include:

• Lower power consumption: Quality LED lights can be six to seven times more efficient than traditional incandescent lights. On average, switching your home from incandescent lighting to LED lights can cut your energy use by more than 80%.
• Longer life span: LED light bulbs can have a life of over 25,000 hours, or three years of 24/7 use! This is 25 times longer than any traditional light bulb. This saves you the time, money and effort involved in purchasing and installing new bulbs!
• More efficient: Traditional incandescent light bulbs release 90% or more of their energy as heat. LED lights cut this by up to 20%! This means more of your energy is going into lighting your home and less into unnecessarily heating it.
• Very compact: Because of their small size, LED lights feature in applications of various sizes and varieties. This means manufacturers can insert LEDs into anything from computers and smartphones to cars and traffic lights.
• Mercury–free: LED lights contain no mercury, unlike more traditional options. As a result, LEDs have a smaller environmental impact than traditional bulbs and can be more easily disposed of, without special disposal procedures.

These benefits are incredible and have lent to the popularity of LED lighting today. As of 2012, Americans installed over 49 million LEDs, saving $675 million in annual energy costs and significantly cutting carbon emissions. You can find LEDs in automobile lighting, traffic lights, TVs and electronics and a variety of other applications.

The Challenges of LED Lighting

LED lighting has several challenges that proper design must overcome. These challenges include:

• Temperature: First, the temperature of the light’s operation contributes to other problems. Up to 20% of the electricity that the LED receives turns into heat. This extra heat impacts the life span and the color of the light.
• Color of the lighting: The LED light’s color relates to the operating temperature. For maintaining a specific color, the temperature also requires careful control. Again, thermal limitations present a major challenge in the design and use of LED lights.
• Life span of the light: High temperatures can severely shorten the life span of the LED. When the temperature of LEDs increases, the life span drops. Therefore, controlling temperatures for brighter, more intense LED arrays will become even more critical in the future to ensure the longevity of the lights.

About Aluminum PCBs

Most common among metal-core printed circuit boards is the aluminum PCB. This type of printed circuit board is built on top of an aluminum alloy base instead of a fiberglass base. The alloy usually consists of a combination of magnesium, aluminum and silumin, altering the properties of the metal to best suit the needs of the application.

All aluminum PCBs consist of the following layers:

• Base layer: The base layer of the PCB is the aluminum alloy sheet. This alloy is typically designed to provide maximum electrical insulation and thermal conductivity.
• Thermal insulation layer: This layer is extremely important in the design of the PCB. Consisting of a ceramic polymer, this layer protects the circuit board from mechanical or thermal damage by offering thermal resistance and viscoelastic properties. This works by absorbing the heat created as the current moves through the circuits and transferring it to the aluminum layer — there it disperses.
• Circuit layer: This layer contributes most to the end function of the board, containing the copper foil circuits needed for the PCB to function.

These layers occur in any number of variations, with one or several thermal and circuit layers depending on the particular application. The layers listed also lend a number of different benefits to aluminum PCBs, which can be of use to several key industries.

Aluminum Printed Circuit Board Types

There are numerous ways the layers above can be altered to create new PCB designs. Each of these variations results in slightly different qualities of the PCB, making it more suitable for some industries and applications over others.

Some types of aluminum printed circuit boards include:

• Flexible aluminum: This relatively new material uses ceramic fillers and polyimide resin to provide excellent insulation and flexibility, all while retaining the aluminum’s impressive thermal conductivity. These PCBs can be formed to connect directly where they are needed. This eliminates the need for cables, connectors and fixtures, which can add to the end cost of the product. Once they are bent, however, they are meant to stay there — these PCBs are not designed to flex constantly.
• Hybrid aluminum: Just as it sounds, a non-thermal material fused to an aluminum base metal creates hybrid aluminum. Usually, the material is a circuit board made with conventional FR-4. By fusing these layers together, the circuit board can dissipate heat more effectively, as well as increase rigidity. These hybrids also tend to be less expensive than entirely aluminum products. The downside, however, is the loss of flexibility.
• Multilayer aluminum: In high-performance power-supply applications, multilayer aluminum PCBs are generally the best. These PCBs consist of layers of thermally conductive dielectrics. While this multilayer approach can handle high performance, they tend to be less efficient when it comes to transferring heat. However, overall these PCBs tend to be effective for basic heat dissipation in more complex designs.
• Through-hole aluminum: For more complex constructions, the aluminum base of a PCB can be pre-drilled and back-filled with epoxy resin. These are highly complex and tend to be labor-intensive projects meant for particularly complicated or specific projects.

Of these aluminum PCB types, flexible and hybrid varieties tend to see the most use in industries like the LED lighting industry.

Aluminum PCBs and the LED Lighting Industry

Aluminum’s performance for use as a printed circuit board core has made it a standard of the LED lighting industry. Its inherent advantages make it a consistently acceptable option for the core of LED printed circuit boards.

Benefits of Aluminum PCBs for LEDs

Aluminum PCBs provide several advantages for their use with LEDs:

• Better value: Aluminum saves on production costs in two ways. Compared to other metals, aluminum is more cost-efficient. By choosing circuit boards that use this metal as its core, the design can avoid adding less cost-efficient heat sinks for thermal regulation.
• Recyclable: Aluminum is readily recyclable and non-toxic.
• Durable: Aluminum is stronger and lasts longer than glass, fiberglass or ceramic printed circuit boards, especially against impact and heat damage.
• Lightweight: Circuit boards made from aluminum don’t have extra weight from the core that they would from other materials. Shipping and handling become more cost-effective due to the lower weight of the aluminum core.
• Improved heat transfer: Aluminum PCB cores transfer heat better than standard cores or other materials, preventing heat damage to the LED components.

Aluminum LED PCB Design Advancements

Advancements in LED PCB design with aluminum cores have allowed for several new and improved capabilities. Aluminum transfers more heat from the printed circuit board and LEDs. Fiberglass PCBs have a limit on the density of LED lights they can accommodate due to heat build-up. Aluminum cores offer greater temperature control compared to standard cores or fiberglass bases.

Benefits of Design Advancements

The ability of aluminum to improve temperature control allows for the following benefits:

• Higher LED density: More lights mean higher operating temperatures that require better thermal regulation from aluminum cores.
• Longer operating time: Aluminum printed circuit board designs better remove excessive heat produced from long operating times.

The Applications of Aluminum LED PCBs

The above benefits make LEDs with aluminum-based printed circuit boards very desirable for a number of applications and industries. Some of the more prominent applications of aluminum PCB LEDs include:

• Telecommunications: Telecommunications equipment often uses LED indicators and displays, and because of the surrounding machinery, the improved heat transfer ability of aluminum-based LED PCBs is extremely useful in this application. Improved durability and decreased weight also make these aluminum PCB LEDs quite desirable within telecommunications applications. Additionally, aluminum PCBs are commonly used in other components of telecommunications equipment as well, including filtering appliances and high-frequency amplifiers.
• Automotive: You can also find aluminum PCB LEDs in cars on indicators, in headlights and brake lights, and in other applications. The durability, longevity and relatively low price make these aluminum PCBs ideal within the automotive industry. Their applications don’t end at LEDs either – aluminum PCBs are commonly used within electronic regulators and power controllers.
• Computer: LED displays and indicators are becoming increasingly common within computer applications, and the heat sensitivity of computer machinery makes aluminum PCB LEDs the ideal solution. In addition to LED applications, computer parts like power devices and CPU boards are commonly use aluminum PCBs because of their ability to handle and transfer heat.
• Medical: Lighting tools used in surgeries and medical examinations commonly use high-powered LED lights, and these LED lights often use aluminum PCBs. This is primarily due to the durability and heat transfer capabilities of aluminum PCB LEDs — this ensures medical equipment is functioning properly regardless of the number of patients cycling through a medical office. In addition to lighting tools, medical scanning technology often uses aluminum PCBs as well.