LedRise LED Lighting Blog

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.

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

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 LumiBar 56 cm LED strips, with SunLike TRI-R CRI98+ LEDs, Nichia Optisolis CRI99+ LEDs or special Nichia Rsp0a Horticulture LEDs:

Series connection with LumiBar Sunlike CRI98+ LED strips:

One LumiBar 56 cm Toshiba-SSC LED Strip Zhaga Sunlike CRI98 warm white 2700K has the recommended current at 350mA, reached at the voltage of 39.5VDC.

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).

According to the standard EN 12464 Light and lighting - Lighting of workplaces -Indoor work places, the light level recommended for office work is the range 500 - 1000 lux - depending on activity. For precision and detailed works the light level may even approach 1500 - 2000 lux. For ambient lighting the minimum illuminance is 50 ulx for walls and 30 lux for ceilings.

Recommended light levels for different types of work spaces are indicated below:

Read more about recommended lighting levels for the home in our blog article.

This article is intended as a guide for those who are considering purchasing UVC disinfection equipment in 2021. These tips should only be considered as suggestions.

Attention buyers! - There are few recognized standards for equipment designed for UVC disinfection of air and/or surfaces. As a result, there are many advertisements and promotions claiming amazing performance with little or no scientific support.

• Ask the seller for copies of scientific papers that prove that his device actually works as he claims. The scientific work(s) should show the actual reduction of a test micro-organism in the environment in which the device is intended to work. 

• Does the product have suitable built-in UV safety sensors for automatic shutdown or does safe operation depend entirely on the operator?
• Does the device comply with NIOSH, UL, IEEE and related safety standards in the country of sale?
• Does the unit emit/generate ozone? If so, does it meet NIOSH requirements. How is the ozone attenuated? (We recommend avoiding ozone equipment, as it poses a safety risk to operators, unless ozone is specifically part of the treatment process and is used in a controlled and safe manner)?
• Is the device used to disinfect medical devices? If so, is it compliant with the requirements of the regulatory body in the EU, USA or country of sale?

• If the device is a UV rod that is used to disinfect a surface (e.g. a worktop or an envelope)

The technical specifications should state the UVC irradiance at a fixed distance from the UV front of the device (e.g. 10 mW/cm² at 2 cm).

The UV dose (irradiance multiplied by exposure time in seconds) should be at least 20-40 mJ/cm² to inactivate viruses on perfectly flat and ideal surfaces (details in this article). Thus, if the irradiance at the target surface is 10 mW/cm², the exposure time should be 2-4 seconds. However, the presence of microscopic gaps on flat surfaces can inhibit disinfection, and disinfection on other materials, such as cloths, may require completely different doses. For example, disinfection of viruses on medical masks may require doses as high as 1000 mJ/cm^2. This is a subject that is currently being researched and our current understanding changes almost daily.

With any UV device, you must NOT look at the UV light or expose your hands from the UV side. UV light is a source of skin burns/cancer and can quickly damage the eyes.

Remember that UV disinfection is based on a "line of sight" between the UV lamp and the target surface. If the UV rays are shaded by texture elements on the surface, the shaded areas may receive much less UV light or no light at all. Disinfection effectiveness is therefore determined by the UV dose to which these areas are exposed.

Like any disinfection system, UVC equipment must be used properly to be safe.

They all generate different amounts of UVC light in wavelengths from 200 - 280 nm. UVC light is much more energetic than normal sunlight and can cause a severe, sunburn-like reaction on your skin and could also damage the retina of your eye when exposed.
Some devices also produce ozone as part of their cycle, others produce light and heat like an arc welder, and still others move during their cycles. In general, all disinfection devices must therefore take into account the safety of both man and machine.

These considerations should be taken into account in the operating manual, in user training and in compliance with appropriate safety regulations.

WHAT DOES IP PROTECTION MEAN?

The index of protection – the IP – is an essential characteristic of most of the electrical devices and it shows the protection rate of the device from any external agents such a solid object or liquids. It is expressed of word "IP" followed by 2 numbers, which show:

the first digit describes the degree of protection rate against solid objects, dust, the solid particles and bodies;
the second digit describes the degree of protection offered against liquids.

The IP rating is relevant when the environment conditions are standard; in special cases and hazardous environments special protection is required.

Although there are numerous combinations of IP ratings for LED strips and fixtures, the most common ones are: IP67, IP65, IP44, IP20. For specially IP rated luminaires you will find each product clearly marked with its IP rating PLUS the highest zone in which it can be installed.

In general, all LED strips have IP20, same with many LED fixtures. IP44 you will find for LED strips inside an aluminum profile with closed end caps and in many spotlights and down lights. IP65 or more is usually used for waterproof LED strips and some special fixtures.
The first digit – protection from foreign bodies

0 – no protection from foreign bodies;
1 – protected against solid objects greater than 50mm(e.g. accidental touch by hands);
2 – protected against solid objects up to 12mm(e.g. fingers);
3 – protected against solid objects greater than 2.5mm(e.g. tools and wires);
4 – protected against solid objects greater than 1mm(e.g. small tools and wires);
5 – protected against dust, limited ingress(e.g. no harmful deposit);
6 – totally protected against dust.

The new Vitasolis™ technology from Nichia are LED light sources with spectrum meant to stimulate activity. 

 This development in based on recent research that has revealed in detail the relationship between light and human behavior. Humans can recognize the brightness and color of light while human circadian rhythms can be affected by different wavelengths, especially the blue-green area. For example, lighting has an effect on the level of activity throughout the day, including wake up in the morning, daytime activities, and nighttime sleep aids.

Vitasolis has a very natural white light and its spectrum contains more energy in the blue-green region, which helps control the human circadian rhythm. The spectral distribution of Vitasolis clearly illuminates the object while maintaining high light efficiency.