Lumistrips LED Professional

Nichia Optisolis LEDs with the full spectrum of sunlight

The latest innovation in LED development is the Optisolis technology form world market leader Nichia. Optisolis™ LED emitters provide a natural light source with a spectrum which achieves the industry’s closest match to that of the standard illuminants, sunlight and incandescent artificial light, having a CRI higher than 98.

Industrial scale indoor agriculture under artificial lighting in closed and fully controlled environments could become the main factor that keeps at bay famine and related conflicts. With increasing population, diminishing area of agricultural land, pollution, global warming and migration to grow plants in a reliable, predictable and efficient way will become even more important in the future. For this reason it is important to understand and corectly apply the concepts of lighting for plant growth and development.

Concepts related to Horticulture lighting

A key factor in the success of indoor plant growth is the efficiency of the lighting system compared with sunlight, in the process of plant growth.

Plants grow via a process called Photosynthesis that converts electromagnetic radiation (light) into the chemical energy needed for growth and development. The other ingredients required are carbon dioxide (CO2), nutrients and water. 

Photosynthesis and PAR radiation

The electromagnetic radiation required for Photosynthesis is defined as photosynthetically active radiation (PAR) and 400 to 700 nanometers has spectral range. Only radiation in this interval can be used by photosynthetic organisms in the process of photosynthesis, to fix the carbon in CO2 into carbohydrates.

Electromagnetic radiation called visible light or simply light for a typical human eye has a spectral range from about 380 to 740 nanometers.

A common unit of measurement for Photosynthetically active radiation PAR is the photosynthetic photon flux (PPF in short), measured in units of moles per second. For many practical applications this unit is extended to PPFD, units of moles per second per square meter.

The theory behind PPF is that every absorbed photon, regardless of its wavelength and energy, has an equal contribution to the photosynthetic process. As in accordance with the Stark-Einstein law, every photon (or quantum) that is absorbed will excite one electron, regardless of the photon’s energy, between 400 nm and 700 nm. 

However, only some of photons are absorbed by a plant leaf, as determined by its optical properties and the concentration of plant pigments. The pigments are Chlorophyll A, Chlorophyll B, and Carotenoids (a/-Carotene, Lycopene, Xanthophyll).

The Chlorophylls A and B give plant leaves the characteristic green color because they reflect most of the radiation between 500 and 600 nanometres.  Plants Where more Carotenoids than Chlorophylls are present plant leaves reflect wavelengths beyond 540nm and have yellow, orange, and red colors. This includes autumn leaves when Chlorophylls have dried away. 

The graph below shows the typical absorptance spectra for Chlorophyll A, Chlorophyll B and Chlorophyll (beta-carotene). Each are explained briefly afterwards:

 

 

 

Product lifetime, Light Bulb vs LED

The typical product lifetime of an incandescent light bulb is 1000 hours. When the bulb reaches the end of its product lifetime, it cannot emit light anymore. Typically, just before, there is spark or pop, as the filament inside breaks down.

LEDs use a different meaning for product life. They are the only light sources that over time lose brightness, even up to 90% of initial flux. Eventually, LEDs will also fail completely. However, some emit visible light even after decades.

For example, a Nichia LED with 60,000 hours typical product lifetime will continue to light well beyond the 60,000 hours rated life. Under normal operating conditions, it will even after 200,000 hours.

LED lifetime is the time interval the product can still serve its intended purpose.  The time passed until a LED has 70% of the initial brightness is equal with the product life, L70 lifetime.

For all reputable lighting manufacturers and sellers, LED lifetime is equal with L70 lifetime. At this point, the LED is considered end-of-life and has to be replaced.

The innovative SunLike LEDs from Seoul Semiconductor are the first natural spectrum LEDs on the global market. For the first time an LED can emit light that closely matches the spectrum of natural sunlight.

The special ability to have a spectrum close to sunlight comes from using a new LED design, 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 chip and replacing it with a purple light one, 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 do not have a blue energy peak associated with eye discomfort and poor sleep patterns.

For LED technology, from the LED chip to related products such as LED lamps, modules and fixtures, high operating temperature can result in mechanical failure and significant drop of performance.

How a LED behaves when subjected to higher operating temperatures is directly related to its quality. High quality LEDs (such as Nichia or Cree) will function within parameters at high temperatures too, while low quality LEDs will break down, change their color, loose brightness or a combination of these. 

1. complete failure of the LED
2. light output is decreased permanently (Lumen Degradation) even if the issue with high temperature is solved
3. light output is decreased temporally while the LED functions at high temperature
4. the color temperature of the white LED changes

 When designing, building or installing a UV light, two key questions must be answered first:

"How irradiance does it need to have?"

 

"What is the required exposure time?"

While there are many studies that show the effectiveness of UV light in disinfection or sterilization, a high variance of the results exists, which presents a challenge to find an answer to these questions. 

We will present our recommendations by analyzing the results of 413 reasearch papers, as found in the compilation "Fluence (UV Dose) Required for up to 99% disinfection from Viruses, Bacteria, Protozoa and Algae"  that can be downloaded at the links below:

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

The research studies present the fluence required to achieve a log reduction from 1 to 5, for different types of UV sources.

 

Basic LED principles:

An LED (light-emitting diode) is a semiconductor light source that emits light when current flows through it. Light is energy in the form of photons that emit when electrons in the semiconductor recombine with electron holes. 

The higher the current flow, the brighter the LED becomes. However, the circuit is not perfect and some of the current is converted to heat instead of light. When the current reaches a certain value, the heat generated is so high that the semiconductor is permanently damaged. In most LED data sheets, this important limit is specified as "Absolute Maximum Current".

Even if the LED operates below the maximum current, the heat will slowly damage the LED, causing its luminous flux (light output) to gradually decrease. The time when the LED luminous flux is only 70% of the initial value is commonly referred to as "LED life".

For LEDs to have a very long life of 50,000h or more, a current level well below the absolute maximum current is required, which is referred to as the "typical" or "recommended" current. 

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.