Adjustable white LED is one of the key elements of human-oriented lighting. Until today, different solutions are currently available, but none are easy to apply or cost-effective enough to accelerate the proliferation of human-centered lighting in architectural projects. A new method for adjustable white light solutions can provide flexible lighting for a variety of occasions without sacrificing output or exceeding project budgets. Phil Lee, senior lighting engineer at Meteor Lighting, will compare this new technology called ColorFlip™ with traditional tunable white light solutions and discuss current tunable white light issues.

Before entering the new adjustable white light technology, it is necessary to check the shortcomings of traditional adjustable white light solutions to fully grasp the latest advances in color adjustment technology. Since the emergence of LED lighting, with the expansion of potential applications, people have known that LED lamps can provide different light colors. Although adjustable white lighting has become one of the biggest trends in commercial lighting, the demand for efficient and economical adjustable white lighting is rising. Let’s take a look at the problems of traditional tunable white light solutions and how new technologies can bring changes to the lighting industry.

Problems with traditional adjustable white light sources
In the traditional LED lamp light source, surface mount LEDs with individual lenses are scattered on a large circuit board area, and each light source is clearly visible. Most tunable white light solutions combine two sets of LEDs: one set is warm white and the other is cool white. The white between the two color points can be created by raising and lowering the output of the two color LEDs. Mixing colors to the two extremes of the CCT range on a 100-watt luminaire can result in a loss of up to 50% of the total lumen output of the light source, because the intensities of warm and cool LEDs are inversely proportional to each other. In order to obtain a full output of 100 watts at a color temperature of 2700 K or 6500 K, twice the number of lamps is required. In the traditional adjustable white light design, it provides inconsistent lumen output across the entire CCT range and loses lumen intensity when mixing colors to the two extremes without complex control mechanisms.

Figure 1: 100-watt traditional monochromatic adjustable white light engine

Another key element of adjustable white lighting is the control system. In many cases, adjustable white lamps can only be paired with specific drivers, which may cause incompatibility issues in retrofits or projects that already have their own dimming drivers. In this case, an expensive independent control system needs to be specified for the adjustable white light fixture. Since cost is usually the reason that adjustable white light fixtures are not specified, independent control systems make adjustable white light fixtures impractical. In traditional tunable white light solutions, the loss of light intensity during the color mixing process, undesirable light source visibility, and expensive control systems are common reasons why tunable white light fixtures have not been used more.

Utilize the latest flip chip technology
The latest tunable white light solution uses flip chip CoB LED technology. Flip chip is a directly mountable LED chip, and its heat transfer is 70% better than traditional SMD (Surface Mount Diode). It significantly reduces the thermal resistance and improves the level of heat dissipation, so that the flip-chip LED can be placed tightly on a 1.2-inch chip. The goal of the new tunable white light solution is to reduce the price of LED components without compromising performance and quality. Flip chip CoB LED is not only more cost-effective to produce than SMD LED, but also its unique packaging method can provide a large number of lumens at high wattage. Flip chip CoB technology also provides 30% more lumen output than traditional SMD LEDs.

The advantage of making LEDs more concentrated is that they can provide uniform light in all directions.

Owning a compact light engine can also realize the adjustable white light function in lamps with smaller apertures. The new technology provides the lowest thermal resistance on the market, with only 0.3 K/W junction to the Ts measurement point, thereby providing consistent performance and longer service life in higher wattage lamps. Each of these 1.2-inch CoB LEDs produces 10,000 lumens, which is the highest lumen output of a tunable white light solution currently on the market. Other existing tunable white light products have an efficiency rating of 40-50 lumens per watt, while the new tunable white light solution has an efficiency rating of 105 lumens per watt and a color rendering index of more than 85.

Figure 2: Traditional LED and flip chip CoB technology-luminous flux and heat transfer capability

Figure 3: Comparison of lumens per watt between traditional tunable white light solutions and new technologies

Advantages of new technology
Although traditional adjustable white light solutions need to increase the number of lamps to equal the output of monochromatic lamps, the new unique design and proprietary control panel can provide maximum lumen output during color adjustment. It can maintain up to 10,000 consistent lumen output during the color mixing process from 2700 K to 6500 K, which is a new advancement in the lighting industry. The adjustable white light function is no longer limited to low-wattage commercial spaces. Large projects with ceiling heights greater than 80 feet can take advantage of the versatility of having multiple color temperatures.

With this new technology, the candlelight requirement can be met without doubling the number of lamps. With minimal additional costs, tunable white light solutions are now more feasible than ever. It also allows lighting designers to fully control the color temperature even after the lighting equipment is installed. It is no longer necessary to determine the color temperature during the planning stage, because with new advances, on-site adjustable CCT becomes possible. Each fixture adds approximately 20% additional cost, and there is no CCT limit for any project. Project owners and lighting designers can flexibly adjust the color temperature of the space to meet their needs.

Precision engineering can achieve a smooth and uniform transition between color temperatures. LED light source imaging will not appear in this technology, which provides more ideal lighting than traditional adjustable white light engines.

This new method differs from other adjustable white light solutions on the market in that it can provide high lumen output for large projects such as conference centers. The adjustable white solution not only changes the atmosphere, but also changes the function of the space to suit different events. For example, it satisfies the requirements of a multifunctional conference center, that is, it has a lighting fixture that can be used as a bright and strong light for trade shows and consumer displays, or it can be dimmed to softer and warmer lights for banquets. By adjusting the intensity and color temperature in the space, not only can mood changes occur, but the same space can also be used for different occasions. This is an advantage that is not allowed by the traditional metal halide high bay lights commonly used in conference centers.

When developing this new technology, the goal is to maximize its practicality, whether it’s a new building or a renovation project. Its new control unit and drive technology make it fully compatible with every 0-10V and DMX control system that meets industry standards. Technical developers realize that controlling adjustable white light fixtures can be challenging because different manufacturers use different methods. Some even provide proprietary control devices, which often rely on existing protocols with customized user interfaces or hardware. It is paired with a proprietary control unit, enabling it to be used with all other 0-10V and DMX control systems.

Figure 4: Due to the use of micro flip chip on CoB, zero light source visibility

Figure 5: Comparison of the appearance of 2700 K and 3500 K CCT in the conference center

in conclusion
What new technology brings to the lighting industry can be summarized in three aspects-efficiency, quality and cost. This latest development brings flexibility to space lighting, whether in classrooms, hospitals, entertainment centers, conference centers or places of worship, it can meet lighting requirements.

During color mixing from 2700 to 6500K CCT, the light engine provides a consistent output of up to 10,000 lumens. It beats all other adjustable white light solutions with a light effect of 105lm/W. Specially designed with flip chip technology, it can provide better heat dissipation and higher lumen output, consistent performance and longer service life in higher power lamps.

Thanks to the advanced flip-chip CoB technology, the LEDs can be closely arranged to keep the size of the light engine to a minimum. The compact light engine can be integrated into a smaller aperture luminaire, extending the high-lumen adjustable white light function to more luminaire designs. The condensing of LEDs produces more uniform illumination from all directions. Using flip chip CoB, no LED light source imaging occurs, which provides more ideal lighting than traditional adjustable white light.

With traditional adjustable white light solutions, the number of lamps needs to be increased to meet the foot-candle requirements, because the lumen output is significantly reduced at both extremes of the CCT range. Doubling the number of lamps means doubling the cost. The new technology provides consistent high lumen output across the entire color temperature range. Each luminaire is about 20%, and the project owner can take advantage of the versatility of adjustable white lighting without doubling the project budget.