Newsletter - fh-muenster.de · Volume 11 Issue 06 June 2017 5 Erasable Ink for Laser 3-D Printing...

NewsletterTailored Optical Materials

David Böhnisch

Reseach &

Development

Latest

Publications

Novel

Patents

Thomas Jüstel

June 2017Volume 11 Issue 06

Erasable Ink for Laser 3-D Printing

Conception: Prof. Dr. rer. nat.Thomas Jüstel

Edited by: David Böhnisch

Contact: [email protected]

Research & Development ....................................................................................................................... 3

Acuity licenses disinfection SSL technology from Vital Vio .......................................................... 3

Erasable Ink for Laser 3-D Printing ................................................................................................. 5

Seoul Semiconductor introduces world’s smallest 24W DC LED drivers ...................................... 7

SSL Growth Strategies and USDA Corn Breeding Objectives ........................................................ 9

Bio-Effective Lighting for Humans, Livestock and Plants ............................................................ 13

Latest Publications ................................................................................................................................ 17

Eu3+-doped Bi4Si3O12 red phosphor for solid state lighting: microwave synthesis,

characterization, photoluminescence properties and thermal quenching mechanisms .................. 17

Dual emission of Ce3+,Mn2+-coactivated Ca3YNa(PO4)3F via energy transfer: a single component

white/yellow-emitting phosphor..................................................................................................... 17

Preparation and luminescence properties of Li2MgZrO4:Mn4+ red phosphor for plant growth ..... 18

A promising orange-yellow-emitting phosphor for high power warm-light white LEDs: Pure-

phase synthesis and photoluminescence properties........................................................................ 18

Mn2+ activated MgAlON transparent ceramic: A new green-emitting transparent ceramic

phosphor for high-power white LED ............................................................................................. 19

Novel Patents ......................................................................................................................................... 20

Promoting fruit and vegetable middle-stage growth of led light source ........................................ 20

Efficient Q-led package structure manufacturing method ............................................................. 20

Display devices comprising green-emitting quantum dots and red ksf phosphor .......................... 20

A kind of remote phosphor glue coating covering method and product ........................................ 21

Spiral shaped led packaged bulb production method ..................................................................... 21

Volume 11 Issue 06 June 2017

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Research & Development

Acuity licenses disinfection SSL technology from Vital Vio

The VioSafe White Light Disinfection

technology uses violet light mixed with white

light to enable continuous disinfection of

spaces ranging from hospital rooms to

athletic locker rooms.

Acuity Brands has announced a licensing

agreement with startup Vital Vio that will

enable Acuity to embed the VioSafe White

Light Disinfection technology in its LED-

based lighting products. Acuity said it would

utilize the VioSafe technology across its

product lines and target applications such as

food processing and service facilities,

cleanrooms and laboratories, sports facilities,

educational facilities, hotels and

transportation hubs, and even offices. VioSafe

uses violet solid-state lighting (SSL) to slowly

destroy bacteria while also including white

light for functional illumination.

We first learned of Vital Vio at Strategies in

Light (SIL) earlier this year when Colleen

Costello, president and co-founder, presented

at the Investor Forum. Indeed, we covered

that presentation in our Top Five Video

presentation from SIL.

It’s well known that ultraviolet (UV) light can

be used for disinfection and sterilization. We

first covered the potential of UV LEDs in

such an application after an SIL presentation

back in 2014.

But UV light is not safe for humans and isn’t practical in open spaces. Costello explained

that the violet light is safe for humans and that

the pathogen-killing phenomenon in VioSafe

is quite different from that associated with

UV. Costello said the technology targets

specific molecules in bacterial cells and

delivers an overload of oxygen that explodes

the cell.

The VioSafe White Light Disinfection

technology from Vital Vio will allow Acuity

Brands to offer LED-based light fixtures

that disinfect spaces continuously.

But such sanitation takes time, and thus the

characterization as a continuous disinfection

technology. So a VioSafe luminaire would be

lit continuously in a space such as a sports

locker room. Costello said that the potential is

90% of bacteria in a room destroyed in one

day. And the white light in a VioSafe fixture

can be powered off to save energy when

people aren’t present.

At SIL, Costello said while the company was

building some of its own lighting products,

the preferred business model was one of

supplying enabling technologies such as

LEDs and licensing intellectual property (IP).

And that model is precisely what has

happened in the Acuity deal.

Acuity can quickly scale the product across

many markets and applications. “Acuity Brands' extraordinary reach, reputation, and

ingenuity sets the foundation for

commercializing this invaluable technology

that will make it easier for customers to make

the switch to lighting that both disinfects and

illuminates in environments where it is

needed most," said Costello.


4

“We are excited about adding this important technology to our luminaire and controls

platforms,” said Acuity Brands Lighting senior vice president Rick Earlywine. “It is another example of using LED and software

technology to extend the limits of how

lighting can be used.”

Vital Vio, however, is not the only company

pursuing such continuous disinfection

technology. Kenall Manufacturing has a

luminaire line called the Indigo-Clean

Continuous Disinfection family. Indeed,

Kenall won an LEDs Magazine Sapphire

Award in 2016 for the Indigo-Clean product.

It's not clear at this time if there may be

conflicting IP between Vital Vio and Kenall.

Vital Vio was launched out of Rensselaer

Polytechnic Institute (RPI) and VioSafe is

based on IP developed at RPI. The IP behind

Kenall’s product came from the University of Strathclyde, and Kenall has exclusive North

American rights to the IP. Both companies

have said they have patents that cover the key

elements of disinfection using light in the

violet spectral region.

Source:

http://www.ledsmagazine.com/articles/2017/0

5/acuity-licenses-disinfection-ssl-technology-

from-vital-vio.html


5

Erasable Ink for Laser 3-D Printing

When engineers build a complex structure

such as a bridge or office tower, part of the

effort involves erecting a scaffold, pieces of

which are removed as the larger structure

takes shape. A selectively removable scaffold

could also prove handy in the much-smaller-

scale world of 3-D printing, and in particular

for the direct laser writing (DLW) used to

build up structures such as photonic crystals,

micromotors and artificial cells. But such

selectively removable DLW elements have

been tough to achieve.

Now, researchers from the Karlsruhe Institute

of Technology (KIT), Germany, have

developed an “erasable ink” for DLW 3-D

printed elements that could provide just such

a capability (Angew. Chem. Intl. Ed., doi:

10.1002/anie.201701593). The team believes

that the process—which can be combined

strategically with durable, standard DLW

materials to create scaffolds that can be

chemically snipped away at preselected

points—could find use in fabrication of

complex conductive surfaces, scaffolded 3-D

cell cultures for biomedical research, and

more.

Cleavable bonds

DLW works by scanning a femtosecond

pulsed laser across a liquid photoresist

substance (either by moving the working

stage or by adjusting the beam path). As the

laser selectively hits the target, nonlinear

multiphoton absorption causes the photoresist

material to polymerize, allowing complex

structures to be built up a layer at a time. The

method has become an important part of the

micro- and nanotechnology toolkit, and is

now routinely used to build complex 3-D

structures for photonics, microfluidics, tissue

engineering and a range of other areas.

To extend the technique to provide laser-

written scaffolds for which microstructures

could be removed on demand, the KUT

team—led by OSA Fellow Martin Wegener

and Christopher Barner-Kowollik—looked

directly at the chemistry of the photoresist

itself. Specifically, they set themselves the

task of designing a photoresist that would

include phenacyl sulfide. That chemical,

when activated by 700-nm light, forms

disulfide bonds that are robust—but the bonds

also fall apart easily in the presence of

another, commercially available chemical

trigger, dithiothreitol (DTT). A simple DTT

chemical bath thus can erase the scaffold

structures.

The KUT team developed an erasable 3-D printing

material (green bars) that could be laser-written (left)

and then selectively dissolved away (right), allowing

the creation of partly removable laser-written

scaffolds for micro- and nanotechnology. [Image: KIT]

The team was able to create “a variety of structures comprising line arrays, woodpile-

like structures, layers, and blocks” using the photoresist, and thereby to demonstrate its

potential use in production 3-D printing—the

“fundamental units” of which, the authors point out, “are always fine lines, free-standing

units, layers or bulk material.”


6

Getting to a selectively erasable scaffold

Making the scheme selective—such that parts

of a scaffold might be removed while other

sections remain intact—involved combining

the new photoresist with partial scaffolds

made of acrylate-based photoresist materials

that won’t break down in the presence of DTT. To test the system out, the KUT

researchers first used DLW to write a

repeated linear array of control structures (at

300-nm spacing) in the acrylate-based

material. They then wrote in additional fine

linking structures across those lines using

their erasable phenacyl sulfide material. The

result was a network of complexly linked

erasable and non-erasable bonds. Subsequent

exposure to DTT broke only the erasable

bonds, leaving the original control structures

intact—a finding confirmed with scanning

electron microscopy of the surface.

The team stresses that the new erasable resist

substance can be “readily synthesized,” and that the other components of the process, such

as DTT, are commercially available. As to

specific applications, the researchers suggest

a number of candidates, including processes

that need durable scaffolding materials that

can still be removed during or after

fabrication—“for example, when using expensive or unique samples,” or in “complex architectures in need of a removable support

frame.”

Source:

https://www.osa-

opn.org/home/newsroom/2017/may/erasable_

ink_for_laser_3-d_printing/


7

Seoul Semiconductor introduces world’s smallest 24W DC LED drivers

Seoul Semiconductor

(www.seoulsemicon.com) has developed the

industry’s smallest phase-cut DC LED driver

series, with a power density 10X higher than

conventional LED drivers. The NanoDriver

Series is the world’s smallest miniature converter at just 13.5mm wide, and is

available in four versions rated for 16W and

24W output power for operating LED lighting

with input power of 120V or 230V (50 –

60Hz), and can be driven by AC or DC power

supplies. Manufactured with Seoul

Semiconductor’s original Acrich technology, the NanoDriver Series features an IC directly

attached to the substrate, dramatically

reducing the size of the converter.

“The new NanoDriver Series will be a game-

changer for lighting designers by enabling

them to reduce the size, weight and volume of

their light fixtures,” explained Keith Hopwood, executive vice-president at Seoul

Semiconductor. “This breakthrough in size reduction for the NanoDriver Series is the

result of the company’s continuing investment in high voltage LED technology,

combined with a unique power topology that

results in smaller size, increased efficiency

and lower costs.”

In the future, Seoul Semiconductor will also

launch the MicroDriver Series high

performance drivers for LED lighting fixtures

from 900 to 2400 lumens. The MicroDriver

Series is designed with a miniature package

that reduces the size of the converter by more

than 10X to enable the integration of the

control circuitry with the external driver,

making it possible to mount more light

sources on the board, or reduce the size of the

board.

The NanoDriver Series requires few external

components, and delivers 16W or 24W of

output power in a package just 13.5mm x

13.5mm x 1.42mm. These drivers are ideal

for downlight, flush mount, track and

spotlight fixtures. Their small size enables

ultra-thin and novel fixture designs in wall

sconces, making conventional lamp

replacement possible without the need for a

large volume recess for the driver, or a

reduction in the light output.

The resulting decrease in the LED drivers’ physical size has significant business

implications for the lighting industry, giving

lighting designers the ability to shrink the size

of light fixtures by as much as 20%, which

reduces shipping and storage costs. Because

conventional LED drivers are both heavy and

bulky, they are typically shipped via sea

freight from manufacturers in Asia to

European and North American fixture

companies, with transit times up to six weeks.

The NanoDriver Series are small and

lightweight enough to make airfreight

practical and economical, reducing transit

time and making the overall supply chain

more flexible and responsive.

The NanoDriver Series is available in four

models rated for output power of 16W and

24W, for LED assemblies operating at input

voltages of 120V or 230V (50 – 60Hz). The

drivers have typical efficiencies of 85% and

power factor correction (PFC) of <0.9, and

are rated for inrush current of <300mA, with

an over-temperature protection feature that

limits the LED current at temperatures above

160°C. Operating temperature range is -40° to

+70°C (ambient) and -20° to +85°C (at TC

point).


8

The drivers are UL recognized, provide

flicker-free, low ripple current operation for

phase-cut dimmers, and are compliant to

California Title 24, enabling lighting

designers to meet the most challenging design

requirements, including low flicker, high

power factor, Class B EMI and 2kV surge.

The NanoDriver Series LED drivers are

available immediately from Seoul

Semiconductor. To learn more about the

NanoDriver Series please visit

http://www.seoulsemicon.com/en/technology/

drivers .

Source:

http://www.displayplus.net/news/articleView.

html?idxno=80337


9

SSL Growth Strategies and USDA Corn Breeding Objectives The SSL horticulture lighting industry has

become one of the fastest growing branches

of lighting worldwide. Much research has

already been done in regards to horticultural

SSL technology and continues to be

rigorously explored. While most other inputs

for plant growth are monitored and

controlled based on plant needs, it is still

common practice for light control to be

rudimentary (on/off). Brandon Newkirk,

Marketing Communications Manager at

LumiGrow Inc., gives a short overview on the

current state of dynamic LED lighting with a

focus on USDA corn breeding trials and

objectives.

It has become commonly understood that

supplemental lighting is an efficient way to

address the shorter days and longer nights that

winter’s invasion brings. Seasonality carries with it diminished light intensity from the sun

at various times of the year. Artificial lighting

can be used to provide supplemental light in

addition to sunlight to plants. Artificial light

can also be the sole source of radiation for

various indoor growing environments.

The main aspects to consider when providing

light for plants indoors is the quality,

intensity, and photoperiod. Quality refers to

the actual wavelengths of light provided to

plants. Total intensity of light at the plant

canopy is crucial and is a function of light

fixture intensity, beam angle, fixture

arrangement, and daily light integral (DLI),

which is the amount of PAR received each

day as a function of light intensity.

Photoperiod refers to the amount of time the

plant receives light throughout a 24-hour

timeline.

Different crops have different photosynthetic

saturation points, where additional light

beyond this point becomes wasted. For this

reason, it’s important to monitor the DLI to

optimize energy-use versus plant

photosynthetic rates. Research institutions,

commercial growers, and commercial

research teams such as LumiGrow’s in-house

plant science research group are laying the

foundational knowledge to understand how

best to use light as a growth variable for

specific growth goals. As horticultural LEDs

move into the ag-industry spotlight, we are in

the midst of a technological paradigm shift

due to increased efficiency and controllability

that LED solutions offer.

USDA Uses Artificial Lighting for Corn

Breeding

There has already been much written about

light requirements for crop production, but

plant breeding remains a topic less explored.

Plants have adapted to grow in certain

climates, from subtropical to northern

climates. Thus, the time it takes to grow from

a seed to harvest can differ among different

varieties, typically longer for subtropical and

shorter for varieties grown in the north, as

growing seasons are typically shorter in the

north. Light intensities and photoperiods can

further affect this, as the same variety can

flower at different times if grown under

different photoperiods. Although corn will


10

flower under most photoperiods (day-neutral

plant), the time to form tassels and silks (male

and female flowers, respectively) will differ

based on varieties. This presents a challenge

for breeders who would like to cross corn, as

they need flowering times and tassel

formation to synchronize. Requirements are

different for every corn variety but, in

general, they need a high intensity of light to

produce a healthy corn plant.

The USDA-ARS Station is home to the

largest collection of maize germplasm in the

world, which they make available for national

and international research. The maize

collection consists of over 20,000 accessions

from all over the world. The USDA Station is

using artificial lighting to aid in the

development of new and more nutritious corn

varieties for organic producers finally using a

property called gametophytic incompatibility.

They’ve made major advancements in the ability to prevent organic corn from being

pollinated by unwanted pollen, a problem

that’s been prevalent in recent years due to GMO seed.

Researchers at the USDA have been using

supplemental light to improve greenhouse

light quality and intensity. They have used

LEDs to decrease the high levels of heat from

their HPS fixtures. HPS and heat is a problem

with tall varieties of corn. As the corn grows

closer to the high levels of heat emitted, the

pollen can often become damaged. Some

varieties of corn only grow a few feet in

height, but others can get well over 10 feet

tall. For tall varieties of corn, high ambient

heat from lighting fixtures brings challenges

in successful germplasm regeneration. Cooler

LED fixtures offer a solution to this

production system issue common to many

crop breeders.

Researchers at the USDA-ARS Station have

begun to experiment testing the effects of

spectral variability with some interesting

preliminary results. Using controllable LED

fixtures to adjust the ratios of wavelengths of

red and blue light emitted, they have seen

increased control over growth characteristics

in specific treatments. Preliminary results at

the USDA Station have seen that blue light

treatments can potentially induce corn to

flower 3 days earlier, and plants grown under

red light can have thicker stocks and more

vegetative growth. More data must be

gathered before any conclusive statements can

be made about the significance of the results,

but this is just one instance where light

spectra have been used to achieve similar

control over desired crop characteristics.

Functional Differences of SSL vs. Non-SSL

Lighting Strategies

Whether your goals are for breeding or

production purposes, the variables between

SSL and non-SSL lighting strategies remain

similar. As a new technology and not simply

a refinement of an existing one, SSL

technology implementation requires that new

variables be considered. Given the leaps and

bounds that SSL technology has made in

efficiency and quality compared to

conventional horticultural lighting, the

agricultural industry is learning fast.

Absorbance spectra of Chlorophyll a and Chlorophyll b

As mentioned before, traditional lighting such

as HPS produces more heat than LED

technologies. This reduction in heat can

provide major benefits, but this change can


11

significantly affect the growth environment.

Traditional growing methods have treated

HPS lamps as a heat source, albeit an

extremely inefficient method for temperature

regulation. When implementing SSL in the

form of LEDs, it’s important to take note of the reduction in ambient heat, and adjust your

temperature control systems accordingly.

Comparison of the spectra of two LED growth lights

and one HPS system with the photosyntetically active

spectrum range of healthy plants

Spectral distribution is another variable when

choosing to use LEDs. Different wavelengths

of light have varied efficiencies in regards to

photosynthesis. Rather than the human eye

response curve, horticultural lighting uses

Photosynthetically Active Radiation (PAR) as

the primary measure. PAR refers to the

spectral range from 400 to 700 nanometers,

the range that plants use in the process of

photosynthesis. LED technology offers the

ability for lighting manufacturers to design

products that target this PAR range.

About State-of-the-Art SSL Grow Light

Systems

The most up-to-date horticulture lighting

fixtures take advantage of the capability for

spectrum tuning and perfect intensity control

to adapt for the required photosynthetic active

radiation spectrum of a plant. Moreover, in

high end solutions the spectral controllability

can be aligned with the stage of plant growth,

i.e. in some crops a blue light treatment

towards the end of flowering elicits beneficial

plant response. Other plants may need a

different spectral profile or prefer different

light intensities during different stages of their

growth. This task asks for sophisticated

controls for dynamic lighting.

Dynamic and sophisticated control

solutions

Using modern control systems such as

wireless solutions like LumiGrow’s SmartPAR™ Wireless Control System, growers can automate lighting schedules in

regards to light intensity, as well as spectral

ratios as mentioned above. Furthermore, such

systems allow the user to create different

lighting zones from any phone, tablet or

computer. Such cloud-based Horticultural

lighting control systems are designed to

enable growers to be more specific and

dynamic with their growth strategies while

providing a robust monitoring platform.

Conclusions

When considering artificial lighting solutions

for horticulture, it’s important to understand the efficiency of your solution, as well as the

science behind how it works. As SSL

technology continues to improve, so will the

automated systems that support the use of

lighting tools to drive plant growth. The

dialogue between plant science and lighting

technology will remain important as the

industry continues to rapidly evolve. It’s important that horticultural experts and

lighting specialists work with each other so

that growers are given the best tools to

continue improving their own production and

research goals. Some ongoing research, for

instance, takes into account biological

feedback systems that could monitor how

efficiently the plants are using the light for


12

photosynthesis. It is certainly an exciting

topic for the future.

Source:

https://www.led-professional.com/resources-

1/articles/ssl-growth-strategies-and-usda-

corn-breeding-objectives


13

Bio-Effective Lighting for Humans, Livestock and Plants

Mood lighting is often misleadingly

interpreted as HCL. But HCL is much more

because it includes biologically effective light

that is beneficial or dangerous, depending on

the correct application. While the relevant

parts of the radiation spectrum may differ,

light is also biologically effective for plants

and animals and it is used to achieve well-

defined effects. Volker Neu, General Manager

LED at Vossloh-Schwabe Lighting Solutions,

presents examples, discusses similarities and

differences between humans, animals and

plants in respect to the relevant spectra, and

scrutinizes possible consequences.

In plant growth and animal farming, a lot of

research is done to find opportunities to

improve growth, health and productivity. In

some respects even more is known about the

former than about HCL. The article sets out to

detail the various biological effects of

identical wavelengths on plants, livestock and

humans. Current knowledge about the

different genera is compared and is used as

inspiration to consider possible transfers to

HCL (Human Centric Lighting).

The Status of Horticulture Lighting

Standardized use of bio-effective spectral

lighting control has been common in the field

of plant cultivation for quite some time.

Industrial use is being made of available

knowledge and intensive research conducted

into further possible correlations. But findings

delivered by fundamental research into plant

behavior under different wavelengths are also

available.

Stimulated via cryptochromes, phototropins

and phytochrome, plants have been found to

grow sturdier leaves and become more stress-

tolerant at wavelengths of less than 400 nm

(UV radiation). The above-named

photoreceptors are active not only when

subjected to this kind of shortwave radiation,

but also in combination with the wavelengths

displayed in the graph below. In addition, low

doses of UV radiation are used as a means of

protection against fungal infestation.

The wavelength range between 400 nm and

500 nm produces a series of effects but does

not have to be applied in high doses.

Irradiation with blue light can largely prevent

plants from drying out (transpiration). In the

field of household appliances, modern

refrigerators are provided with blue light for

the vegetable compartment, which helps to

keep fruit fresh for longer.

Chlorophyll a and Chlorophyll b absorption spectrum

(a) [1], and emission spectrum of a horticulture

dedicated COB LED module (b) [2]


14

However, this wavelength range is also

responsible for stunting longitudinal plant

growth, which can lead to short intervals

between leaves (dwarfism/squat plants) and

thus exerts a negative effect.

Applying light within the green wavelength

range (600 nm to 700 nm) counters the

growth-stunting effect of blue light and

prevents short intervals between foliage tiers.

Red light (700 nm to 800 nm), in turn, causes

plants to produce larger blossoms and to grow

in a more compact form. This wavelength

range from 700 nm to 800 nm exerts a major

influence on the plant, especially on the flavor

of edible plants.

As a result, correctly blending these different

wavelength ranges can produce light

scenarios that not only facilitate perfect plant

cultivation, but also yield optimization

potential with regard to energy consumption

and plant quality. Energy efficiency is

achieved by making spectral adjustments to

suit the growth phase. Multichannel systems

make it possible to suppress undesired growth

factors at any given point in time. Premature

illumination with longwave red light will not

improve root growth. However, red light –

provided at the correct point in time – will

allow fruit such as vine tomatoes to ripen in a

targeted manner. Ensuring fruit ripens at the

same point in time maximizes harvesting

efficiency. However, this spectral exposure

cannot be defined via an integral value for the

light source. A single mol value, without any

differentiation of the radiated wavelengths,

makes no sense here and can only serve as an

indication of the light source’s output. For practical use, it is much better to split light

into wavelength ranges and dedicated

illumination tasks. This would be comparable

to the integral Ra and the indices of the

individual colors.

The sophisticated Lighting E ualize , an 11 channel system that allows spectral tuning to better control

plant growth. Besides controlling growth or larger

blossoms, this system offers several additional

benefits

Current Situation in Animal Husbandry

Lighting

Use of spectrally adjustable light sources is

not yet as advanced in the field of animal

husbandry. While some of the effects are

known with regard to livestock farming, the

underlying biological reasons have yet to be

understood. By contrast, the use of artificial

lighting in livestock housing is becoming ever

more common, the reasons for which can be

seen in the shift towards keeping livestock in

closed sheds without daylight and the

considerable global increase in the demand

for meat. The demand for poultry has

advanced to the number one spot worldwide

and even outranks pork.

Poultry is inexpensive, healthy and quick to

farm. For the seven-week period in which a

chick grows into a 1.8-kg chicken, the

following lighting scenarios are favored on

the basis of currently available information.

Green light results in good muscle growth

during the first weeks of life, while blue light

increases hormone production. As an

orientation aid and to improve food uptake, a

yellowy-white light is used. If chickens tend

towards mutual pecking, red light can lower

their aggression levels. A positive influence

can also be exerted on the problem of

cannibalism and the use of antibiotics, but

tests have yet to be carried out on which exact

wavelengths are involved. The shortwave


15

range around 380 nm and the red range

between 700 nm and 800 nm are set to be

decisive for new findings. The visual

spectrum of a chicken is considerably broader

than that of a human. For that reason, they are

difficult to evaluate using conventional light

sources (adjusted to V( )). The same is true for other poultry such as ducks, geese and

turkeys.

It is also worthy of note that blue light at 480

nm keeps cows awake and increases the yield

of ongoing milk production by 8%. Cows

have no visual ability beyond 640 nm.

A more detailed evaluation of the influence of

light on pig farming has yet to be conducted,

but is not currently being pursued due to

current market prices.

The operating technology constitutes another

factor that exerts a key influence on lighting

in such applications. Lighting should feature a

particularly high resistance to flickering and

scintillation.

Livestock and plants process visual stimuli

considerably more quickly than humans.

Operation using constant current would be the

best alternative and could have a positive

effect on poultry and animal health overall.

For dimming purposes, the simple PWM

method should not be used, but rather it

should be possible to configure a “clean” pulse control factor, which would also have to

be synchronized in the case of spectral

(multichannel) lighting. Failure to ensure this

results in stress for livestock, which in turn

has a negative effect on product quality.

Brief Comparison Between Plants, Animals

& Humans

If one now compares the known and tested

“plant spectra” with those currently used in animal husbandry, it is easy to see that the

dominant wavelengths are largely the same.

In this context, no conclusive results can be

provided with regard to the amplitudes of the

spectral composition.

The influence exerted by individual light

spectra as a biological stimulus for humans

has barely been researched. The fact that blue

light (480 nm) is known to suppress

melatonin production can be seen as a first

relevant step towards using HCL in the field

of general lighting.

The sensitivity (receptiveness) to spectral

wavelengths among plants and humans is

similar to that of chickens (Figure 5).

Comparison of wavelengths and their effects in

greenhouses, livestock and human centric lighting

Sunlight provides the basis for all forms of

life and organisms, with only the typical

respective environment affecting the

individual spectra: forest and desert, hill and

dale, land and water. Habitat-based filtering

can produce differences in this respect.

Going by the findings yielded by research,

analyses and tests in all three areas (plants,

livestock and humans), it appears logical to

assume that further similarities between

wavelength-dependent effects will be found.

For instance, in chickens the stress hormone

cortisol can be reduced with “red” wavelengths. Tests involving inmates in US

prisons returned comparable results.

Potential Consequences

In general, there remains a question as to the

correct nomenclature for these processes and

measurable factors. The human field,

measured in lux and lumens, cannot be

extended to wavelengths in the IR and UV

ranges. Melatonin-suppression at 480 nm

cannot be efficiently represented with a V( )


16

curve. HCL does not fit within the

conventional lighting profile. Given a typical

invitation to tender, an HCL-compatible

luminaire would lose out in terms of

efficiency in lumens per Watt.

Tested parameters and representations used in

established niche applications could provide a

basis for a meaningful discussion. Since the

effect of HCL on humans should be described

via the degree of exposure, as for all other

lifeforms and organisms, the unit of measure

of this spectral range should be mol.

However, it would be equally possible to

evaluate the degree of exposure to which any

one species is subjected using the sensitivity

curve of the respective genus, as is already

common practice in chicken farming. But

would “chicken lux” or “gallus lux” apply to all species of bird?

The effect of scintillating and flickering light,

which is currently being researched with

regard to humans and is resulting in new

and/or improved control gear, is already well

known in the field of chicken farming.

Operating frequencies of up to 1 kHz exert a

negative influence on the health of livestock.

Further organisms with a fast “visual” response include plankton and algae. This

circumstance should not be underestimated

for the field of general lighting. Constant-

current- powered multichannel drivers could

have a positive effect on the desired result,

since light would be permanently available.

Conclusions

In the future, standard lighting practices

currently found in the field of animal

husbandry are also set to establish themselves

in the area of general lighting. This also

applies to arguments put forward in favor of

HCL and its advantages since technical

specifications would be largely transferrable.

Clearly defined product features would be

necessary to ensure planning security.

Source:

https://www.led-professional.com/resources-

1/articles/bio-effective-lighting-for-humans-

livestock-and-plants


17

Latest Publications

Eu3+-doped Bi4Si3O12 red phosphor for solid state lighting: microwave synthesis,

characterization, photoluminescence properties and thermal quenching

mechanisms

Europium-doped bismuth silicate (Bi4Si3O12)

phosphor has been prepared by microwave

irradiation method and its crystal structure is

determined using Rietveld method. As-

prepared phosphor consists of spherical,

monodispersed particles with few

agglomeration, high crystallinity, and narrow

grain size distribution. The phosphor can be

efficiently excited in the wavelength range of

260–400 nm, which matched well with the emission wavelengths of NUV LED chips.

The photoluminescence spectra exhibit the

highest emission peak at 703 nm originating from 5D0 → 7F4 transition of Eu3+ under NUV

excitation. The luminescence lifetime for

Bi4Si3O12: 2 at% Eu3+ phosphor decreases

from 2.11 to 1.86 ms with increasing

temperature from 10 to 4λ8 K. This behavior of decays is discussed in terms of radiative

and nonradiative decays dependence on

temperature. The thermal quenching

mechanism of 5D0 emission of Eu3+ in

Bi4Si3O12 phosphor is a crossover process

from the 5D0 level of Eu3+ to a ligand-to-

europium (O2− → Eu3+) charge transfer state.

The quantum efficiency of the phosphor

under 3λ3 nm excitation is found to be 14.5%, which is higher than that of the commercial

red phosphors Y2O3: Eu3+, Y2O2S: Eu3+. The

temperature effect on CIE coordinate was

discussed in order to further investigate the

potential applications.

DOI: 10.1038/srep42464

Dual emission of Ce3+,Mn2+-coactivated Ca3YNa(PO4)3F via energy transfer: a

single component white/yellow-emitting phosphor

A series of Ce3+,Mn2+-coactivated

Ca3YNa(PO4)3F phosphors were synthesized

via a traditional solid-state reaction under a

reductive atmosphere. X-Ray powder

diffraction was used to confirm that the

crystal structure and diffraction peaks of

Ce3+/Mn2+-doped samples matched well with

the standard data. A spectral overlap between

the emission band of Ce3+ and the excitation

band of Mn2+ suggested the occurrence of

energy transfer from Ce3+ to Mn2+. With

increasing Mn2+ content, the emission

intensities and lifetime values of the Ce3+

emission for Ca3YNa(PO4)3F:Ce3+,Mn2+

phosphors linearly decrease, whereas the

energy transfer efficiencies gradually increase

to 89.35%. By adjusting the relative

concentrations of Ce3+ and Mn2+, the emission

hues are tuned from blue to white and

eventually to yellow. These results suggest

that Ca3YNa(PO4)3F:Ce3+,Mn2+ phosphors

have promising application as white-emitting

phosphors for near-ultraviolet light-emitting

diodes.

DOI: 10.1002/bio.3208


18

Preparation and luminescence properties of Li2MgZrO4:Mn4+ red phosphor for

plant growth

Novel double perovskite

Li2MgZrO4:Mn4+(LMZ:Mn4+) phosphor is

prepared by high-temperature solid-state

reaction method in air. Excitation bands

peaking at ~335, 395, and 482 nm of

LMZ:Mn4+ phosphor in the range of 220–600 nm are attributed to the O2-–Mn4+ charge

transfer and the 4A2→4T1, 2T2, and 4T2

transitions of Mn4+ ion, respectively.

Emission band peaking at ~670 nm of

LMZ:Mn4+ phosphor within the range 610–790 nm is assigned to the 2E→4A2 transition

of Mn4+ ion with host lattice vibration, which

indicate that LMZ:Mn4+ phosphor has an

application prospect in the red light-emitting

diodes for plant growth. The optimal Mn4+

ion concentration in LMZ:Mn4+ phosphor is

~0.4 mol%. Fluorescence lifetime and

quantum efficiency of LMZ:0.4%Mn4+

phosphor are ~251.47 s and 32.3% at room temperature, respectively. The influence of

temperature to luminescence properties is

explained by the schematic configuration

coordinate diagram. The luminous mechanism

is explained by the energy level diagram of

Mn4+.

DOI: 10.1016/j.jlumin.2017.05.002

A promising orange-yellow-emitting phosphor for high power warm-light white

LEDs: Pure-phase synthesis and photoluminescence properties

The high correlated colour temperature (CCT)

and deficient thermal stability of widely-used

YAG:Ce and InGaN white light systems

prompt an urgent need for more outstanding

succedaneum phosphors, among which Ce-

doped La3Si6N11 (LSN:Ce) phosphor has the

best performance in the yellow-orange area.

However, it still has not gained popularity due

to its low quantum efficiency and luminance

quality, caused by many factors such as

irregular particle morphology and impure

chemical composition, especially the

difficulty of obtaining a single phase without

LaSi3N5 impurity. By doping with different

alkaline-earth metal elements and adjustment

of the lanthanum/silicon ratio in the raw

materials, LSN:Ce and MLSN:Ce (M = Ca,

Ba and Sr) phosphors with high purity were

synthesised in this work. Compared to Ca and

Sr, doping with Ba produced a better result,

not only in the crystallisation of the LSN

phase, but also in the red shift of the phosphor

emission. To further improve the purity of

LSN phosphors, the Si/La molar ratio was

increased from 2:1 to 1:1.5, and finally

resulting in a single phase when the ratio

reached 1:1. The white LEDs fabricated with

the LSN:Ce & BaLSN:Ce phosphors and

InGaN blue light chips had lower CCTs at

3900 K and 3300 K, indicating the great

potential of the phosphor for application in

high power and display lighting.

DOI: 10.1016/j.jallcom.2017.04.270


19

Mn2+ activated MgAlON transparent ceramic: A new green-emitting

transparent ceramic phosphor for high-power white LED

A novel Mn2+ activated green-emitting

MgAlON transparent ceramic phosphor was

synthesized from

Mg0.21Al2.57O3.80N0.20:0.03Mn2+

(MgAlON:Mn) phosphor powder by

pressureless sintering combining with hot

isostatic pressing. By crystalline structure

refinement and cathodoluminescence (CL)

characterization, it is demonstrated that Mn2+

was dissolved in the spinel lattice and

occupied the tetrahedral site. The ceramic,

retaining high transmittance in UV–vis region

(up to 82% at 800 nm) and excellent thermal-

mechanical properties of MgAlON

transparent ceramic-matrix, shows a strong

green emission at 513 nm under 445 nm light

excitation. Compared with its powder

counterpart, the ceramic phosphor exhibits

higher green color purity, higher internal

quantum efficiency (47%) and lower thermal

quenching. It is suggested that this novel

green solid phosphor could be applied in high

color rendering and high-power white light-

emitting diodes when combined with a red

solid phosphor and a blue LED chip.

DOI: 10.1016/j.jeurceramsoc.2017.04.057


20

Novel Patents

Promoting fruit and vegetable middle-stage growth of led light source

The present invention discloses a feed for

promoting growth of fruits and vegetables,

which is made from led light source near

ultraviolet chip and phosphor, the package

together to obtain the phosphor coating in

near-ultraviolet light chip, the outer surface of

the phosphor comprises red fluorescent

material and a blue fluorescent material and a

red phosphor, the mass ratio of blue

fluorescent powder is (1-2.5): 1. The

inventive plant growth light source excitation

efficiency is high, high light efficiency, broad

spectrum, and it is conducive to plant

absorption. Can be for fruit and vegetable

plants in the middle stage optical element, the

need to adjust the light absorption spectrum

of the effectiveness of fruits and vegetables,

to adapt to the plants in the middle of light by

the specific needs.

CN 106653981 A

Efficient Q-led package structure manufacturing method

The invention provides a kind of efficient Q-

led package structure and production

methods, using quantum dot layer to replace

traditional phosphor layer, the chip is

connected and fixed to the two transparent

substrate to form a sandwich structure, The

entire structure sandwich structure in which

metal armor, metal structure with upper

opening, the chip emits light can be emitted

from the upper chip through a wire, two ends

of the metal structure from lower part is

connected with the outside, the invention

process is simple, production efficiency is

high, cost is low. Quantum dot is sealed

between two pie goserelin functional film

layer between, so that it can be used for a long

time without water and air, reduce the impact

of environmental conditions limit; quantum

dots in the form of film coated on the one

hand to ensure uniform film thickness, so that

more uniform light color.

CN 106653979 A

Display devices comprising green-emitting quantum dots and red ksf phosphor

LED devices emitting white light comprise a

blue-emitting LED, green-emitting quantum

dots (QDs) and red-emitting K2SiF6:Mn4+

(KSF) phosphor. A backlight unit (BLU) for

a liq. crystal display (LCD) comprises one or

more blue-emitting LEDs and a polymer film

contg. green-emitting QDs and KSF

phosphor. The QDs and/or KSF phosphor

may be encapsulated in beads that provide

protection from oxygen and/or moisture.

WO 2017077290 A1


21

A kind of remote phosphor glue coating covering method and product

The invention discloses a kind of away from

the phosphor glue coating covering method

and products, belongs to the field of led

package. It comprises the steps of: S1, firstly,

phosphor glue is coated on the surface of the

lens concave surface, then by the lens

concave surface facing upward vertical to the

static placing the phosphor glue stable; S2 the

morphol. of the lens concave surface facing

down into curing equipment, Until the coating

on the surface of the concave lens is the

phosphor glue curing; S3 after the completion

of the curved lens cover to above the led chip,

led chip, and then the gap between the curved

lens are filled with plastic packaging, the

package adhesive, curing the completion of

led package. This invention also provides the

use of the above obtained product. The

inventive method is easy to achieve the

phosphor glue away from coating covering.

CN 106611812 A

Spiral shaped led packaged bulb production method

The present invention discloses a spiral

shaped bulb production method of led

package body, comprises a light source, the

light emitter and the light source body

includes removably assembled together; the

light source body upper part and lower part of

the light source body, since the invention

components are fit manner is detachably

assembled together, Especially the light

source body, between the lower buckle

assembly methods, to replace the traditional

welding connection or glue pasting assembly

methods, greatly facilitates the assembly and

disassembly of luminophor, also facilitate the

replacement operation.

CN 106609928 A

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