Shining the Spotlight: In-depth LED Product Reviews and Tests

Casambi, a pioneer in Bluetooth Low Energy (BLE) wireless lighting control, has teamed up with LED technology specialist Seoul Semiconductor to offer lighting designers precise control of LED strips, modules and luminaires that use the new SunLike technology that matches the spectrum of sunlight. For the first time, this development puts true human-centered lighting in the hands of designers.

Users can use Casambi's Bluetooth-based wireless control system and app with products that include SunLike series LEDs to precisely adjust the light level, knowing that the spectrum reflects real sunlight, a key ingredient for Human-centric lighting

Human-centric lighting describes lighting designed to work with the natural rhythms of the human body. It is based on the well-known fact that the human eye recognizes the presence of a certain wavelength of blue light in the spectrum of sunlight and derives the time of day from this. In this way, light helps to regulate our sleep-wake cycles and other physical rhythms and has a significant impact on our mood and well-being.

Human-centered lighting takes advantage of this effect by adjusting its brightness and color temperature during the day to mimic natural light.

Casambi allows control of the lights through a timer or a variety of presence/movement sensors and daylight sensors. It can control lights that change colour temperature over a very wide range, and designers have the freedom to configure dimming and create scenes or animations for the application.

As a manufacturer, we aim to use the top performing LEDs in our LED strips and modules. We are particularly focused on mid power LEDs, those that usually use less than 0.3 Watt of energy, are fairly small and require minimal or no cooling. A large share of our product portfolio is based on these LEDs.

Before choosing the best performing LED for our products we have compared more than a dozen models from the top LED manufacturers: Nichia, Osram Opto Semiconductors, Samsung, Philips Lumileds, LG Innotek, Seoul Semiconductor, Cree, Everlight.

For a meaningful comparison, we selected LEDs that function at 65 mA with a voltage between 2.75 and 3.2 V, classified in three groups:

• Cold White (5000-6500K), CRI 80+, for linear LinearZ fluorescent replacements,  for the office or industry
• Warm White (2700K-3900K), CRI 80+, for our LumiFlex LED strips for  linear lighting fixtures, cove lights, desk lamps, usually for residential and hospitality sectors
• Warm White (2700K-3900K), CRI 90+, for our Multibar LED strips with applications in luxury lighting, professional linear lighting fixtures, cove lights for commercial and hospitality sectors

For each category, we compared the luminous flux and luminous efficacy a the junction temperature of 25ºC ("lab temperature") and at a more realistic 100ºC. The comparison data is that from the manufacturer's data sheet.

We also added the performance data of average 5050 and 3528 LED packages because such LEDs are still used by many lighting manufacturers today in low cost linear led modules, fluorescent tubes, lamps, panels or even luxury lighting fixtures.

A micro-sized, high brightness powerful LED package is referred to as CSP (Chip Scale Package) LED. CSP makes the LED smaller while having the same power.

A CSP LED is equal to an LED chip or can be a maximum of 20% larger and thus has a high light intensity. It also does not contain a wire connection like conventional SMD LEDs, a factor that makes it a more stable product, with better thermal performance than conventional LEDs.

As a result, the Direct Mountable Chip technology slashes at one major element of system cost: heat management. With thermal resistance of only 0.3 (℃/W junction to Ts measuring point), heat sinks can be smaller or higher performance can be obtained without increasing the heat sink. 

p>As a manufacturer, we aim to use the newest LEDs technology in our LED strips and modules. One particularly interesting new technology is the Chip Scale Packaged LEDs, known as CSP or Flip-Chip LEDs.

Before choosing the best performing CSP LED for our products we have compared more than a dozen models from the top LED manufacturers: Nichia, Samsung, Philips Lumileds and Seoul Semiconductor.

For a meaningful comparison we selected LEDs that function at 350 and 700 mA with a voltage between 2.75 and 3.2 V.

For each category we compared the luminous flux and luminous efficacy at the usual junction "lab temperature" of 25ºC and at a more realistic 100ºC. The comparison data is that from the manufacturers datasheet.

CSP at 700mA, maximum 2.5 Watt, for street or outdoor lighting, 5000K, CRI 70.

At 25ºC The Nichia CSP LED has 20% higher flux (304 lm) and 27% better efficacy (145 lm/W) than the second performer, Seoul WICOP (247lm and 114 lm/w). Luxeon Flip Chip White 10 has similar performance (242 lm/w 115lmw) to Seoul while Samsung lags somewhat behind (210 lm and 95 lm/w).

With the development of LED lighting and the high demands of consumers, LED chip manufacturers are continuously improving and innovating. The development of Chip Scale Packaged (Flip Chip or CSP) LEDs is such an inovation, with several advantages: no substrate, solderless cabling, small size and high optical density.

CSP, or Chip Scale Package, is defined as an LED package with a size equivalent to an LED chip, or no larger than 20%. The CSP product has integrated component features that do not require soldered wire connections, reducing thermal resistance, reducing the heat transfer path, and reducing potential sources of error.

Usually, a light emitting diode (LED) has two key components, the LED chip that emits the light and the LED package which focuses it, enables assembly into lighting products and transfers the heat away to the heat sink.