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Seoul Semiconductor’s SunLike Series LEDs are the world’s first natural spectrum LEDs, as they produce light that closely matches the spectrum of natural sunlight.

This achievement comes from using a new LED architecture, with a purple emitter in combination with a red, green, and blue (RGB) phosphor mix, unlike conventional white LED that use a blue emitter and yellow phosphor.  By removing the blue LED light source and replacing it with a purple light LED chip, lighting technology is fundamentally transformed. For the first time it is possible to render colors accurately with very low energy use and positive effects on health. Compared with other LED lights, the new SunLike Series does not have a blue energy peak associated with eye discomfort and poor sleep patterns.

Furthermore, an ordinary LED spectrum is very different to sunlight, whereas SunLike’s spectrum is very similar. Thus, the light sources with SunLike Series LEDs will more accurately show the color of objects, as they would appear in natural sunlight. It's natural light spectra has color rendering of CRI-97 – close to CRI-100 of sunlight, and much higher than the CRI-80 of conventional LEDs.

The SunLike packaged LED technology from Seoul is based in part on a Toshiba phosphor technology called TRI-R. By using the TRI-R, the LEDs deliver a uniform and broad spectral power distribution (SPD) that is more like sunlight than are typical phosphor-converted white LEDs.

The applications of this new LED technology, with its diminished blue light peak, similar spectral curve to sunlight, accurate rendering of colors and reduced scattered reflection and glare are many, from Human Centric lighting for our home and office to commercial and art lighting.

NICHIA, the world’s largest LED manufacturer and inventor of the high-brightness blue and white LED, has launched a high density UV-C LED that can help target the inactivation and sterilization of various bacteria and viruses. The new NCSU434B UV-C LED is only 3.5×3.5-mm and offers a high radiant flux of 62 mW operating from 350 mA. Nichia has also documented the germicidal efficacy.

The ultraviolet (UV) performance in the germicidal UV-C band (100–280 nm) has been documented to deactivate including SARs-CoV-2 virus that causes COVID-19. The LED is suitable for usage in water, near-surface, and air disinfection systems, and is commercially available immediately.

LED strips and modules used for lighting fixture use, in general, multiple LEDs.

As operating a single LED generates heat, more is generated when multiple LEDs are mounted on a PCB, due to the mutual effect. As such, in the case of LED strips or modules, the junction temperature (TJ) of each LED gets higher, compared to a single light source. This leads to the decrease in the LEDs lifetime and luminous flux.

For LED strips and modules, a better thermal management is required to minimize TJ and allow a longer lifetime of the installed products. For this purpose, the LED pitch, the PCB base material and the use of aluminum profile must be taken in consideration.

Backlighting with LEDs is considered optimal when the individual LED's light is not noticeable, while the total luminous flux meets the project's requirements. 

The most common backlighting applications are linear lighting fixtures, luminous ceilings and illuminated signs. In all cases, the LEDs are placed behind a diffuse cover.

Uniform backlighting depends on the LED pitch (L) and the distance between the LEDs’ emitting surfaces and the diffuse cover.

Linear LED light fixtures and LED tubes also feature a cover that protects the LEDs and diffuses the light. This cover is usually made of polycarbonate (a resin) and sometimes of glass. 

The cover has a certain light transmission rate that impacts the light's luminous flux and glare. If a cover has a high transmission rate, it will minimize the depreciation rate of the lamp’s luminous flux by reducing the light diffusion. However, the light of individual LED’s can be visible, increasing the glare effect.

Below, we present an evaluation of four covers to showcase light transmission and glare.

Nichia UV LED product line update

Nichia is the world's largest LED manufacturer, leading the supply of innovative LEDs to all markets, including UV and UVC LEDs. Durability, brightness and homogeneity are among the major strengths of the Nichia brand. Furthermore, the fine selection allows greater added value for professional processing.

The UV portfolio of Nichia has new additions:

• New UVC LED: NCSU434A at 280nm and 17.5mW for 0.5W power
• Update of UVC LED: NCSU334B, radiant power increased from 55mW to 70mW at 280nm for 1.8W power
• New UVA LED: NWSU333B, with an amazing radiant power of 4900mW at 365nm for 12.25W power

A cove luminaire is a light line that can be made via an LED strip that is hidden within a Cove in the wall or ceiling that illuminates an adjacent surface. Light is reflected from this surface into the room to be illuminated. For this reason, light lines are generally referred to as cove or indirect lighting.

Cove lighting is a popular trend in lighting design, focusing on human nature and the behaviour of natural light. It is widely used today, with light lines as the main method of lighting interiors.

The attraction is the similarity with the natural light. With the right light source we could imagine that the bay is actually a hidden window to the outside from which the sunlight streams in.

Let's see how we can achieve the best results with cove lighting.

1. Use of energy-efficient light sources

Choose LED modules or strips with high energy efficiency, at least 100 lm/w, and place them within the coving light so that most of the emitted light uses the reflective surface, wall or ceiling that directs it into the interior. Waste of energy for lighting the interior of the bay should be avoided. LED strips with 120-180° are recommended, which should be placed at an angle if possible:

Surfaces that are more absorptive than reflective, like dark paint or wood should be avoided unless the design is primordial to energy efficiency. White ceilings produce the best results.

2. Select an LED light source with the correct light output.

The information below is extracted from the research paper: "Fluence (UV Dose) Required for up to 99% disinfection from Viruses, Bacteria, Protozoa and Algae"  that can be downloaded also on our website at the links below:

PDF: Fluence (UV Dose) Required to Achieve Incremental Log Inactivation of Bacteria, Protozoa, Viruses and Algae

Germicidal action of UV radiation

The effectiveness of sterilization or disinfection with UV light depends on the exposure, time, wavelength and irradiance.

• Exposure or fluence (sometimes called dose) is measured in mJ/cm² (where 1 mJ/cm² = 10 J/m²)
• Exposure time is measured in seconds (s), minutes (m) or hours (h)
• Irradiance is the flux of radiant energy per unit area, in other words how much of the UV radiation power (measured in W = 1000 “miliwatts” mW = 1.000.000,00 “microwatts” μW ) reaches the surface. Irradiance is measured in mW/cm² or W/m² (1 mW/cm² = 10 W/m²) and is dependent on the radiant power, distance and dispersion of the radiation emitted by the lamp source.

Many studies that show the effectiveness of UV light in disinfection or sterilization present in their findings the inactivation of virus or bacteria for a given Exposure in an amount of time, for a given UV wavelength. However, it is difficult to centralize or build a database with so many variables. The most common solution to this problem is to present the fluence required to achieve a log reduction from 1 to 5.

 Log reduction explained

"Log reduction" is a mathematical term (as is "log increase") used to show the relative number of live microbes eliminated from a surface by disinfecting.  For example, a "5-log reduction" means lowering the number of microorganisms by 100,000-fold, that is, if a surface has 100,000 pathogenic microbes on it, a 5-log reduction would reduce the number of microorganisms to one, equal to 99.999% kill rate.

Series and parallel electrical circuits

To power a string or array of LEDs from one LED driver, the LEDs must be connected into an electrical circuit. This can be a series or a parallel circuit. 

We will explain the two types of circuits with examples using our popular LinearZ 56 cm LED strips, with SunLike TRI-R CRI97+ LEDs, Nichia Optisolis CRI98+ LEDs or special Nichia Rsp0a Horticulture LEDs:

Series connection with LinearZ Sunlike CRI97+ LED strips:

One LinearZ 56 cm Toshiba-SSC LED Strip Zhaga Sunlike CRI97 warm white 2700K has the recommended current at 350mA, reached at the voltage of 39.5VDC.

A series circuit with two, three or four LinearZ LED strips is shown below:

Effective and cost efficient disinfection or sterilizing of surfaces, water and objects has become of huge importance. The current COVID-19 (coronavirus) pandemic made this extremely clear. It created a extreme buying spree for everything that can be used in fighting it.  Never before seen shortages of disinfectants, surgical masks, gloves, ventilators and more, happen all across the globe.

The situation is made worse by the fact that many of the materials used for sterilisation are single use and have to be disposed afterwards. More have to constantly produced, exacerbating supply issues. It is time for a more efficient way of killing virus and bacteria, it is time for disinfection with UV light.

Using ultraviolet (UV) light to disinfect or sterilize¹ has actually been embraced by some hospitals since years, by using large, industrial-grade machines to kill microorganisms (including COVID-19) in hospital rooms or on furniture, objects, clothing or instruments. However, such machines are prohibitively expensive for private or business use, as a mobile platform with UV lamps can cost more than 60.000 USD². They are also dangerous for people and have to be used only in empty rooms.

With the current advance in UV LED lighting technology, smaller versions of safe to use UV disinfection lamps can now be available to consumers and companies looking to clean pretty much everything, from office spaces, elevators and living rooms, to phones, computers and even toilet seats.

Widespread use of UV light to fight virus and bacteria can now happen with the technology of continuous disinfection with low intensity UVA light from lighting emitting diodes (LEDs).