How to improve the quality of light source?
In recent years, the development of LED technology in China has been very rapid, the light source has become brighter and brighter, and the light effect has become higher and higher. According to Maslow's hierarchy of needs, after solving the underlying needs of “there is no lightâ€, people gradually turn their attention to the issue of “lighting uncomfortableâ€, and whether it affects human health and whether it is suitable. The environment has raised higher requirements.
So, why should we pay attention to healthy light sources? What is a healthy light source? What is the basis for judging a healthy light source? Follow Wang Yi, then look down and you will understand.
Why promote healthy light sources?
As the saying goes, the eyes are the windows of the soul, and the unhealthy light source is like the storm outside the window, exerting tremendous pressure on the window all the time. If it is light, it will cause discomfort such as dry eyes and swelling, and it will cause irreparable damage such as retinal atrophy damage. Blue light hazards, visual fatigue, ball muscle atrophy, glaucoma and other diseases are four common hazards of harmful light sources.
The harm to the light source can not be underestimated, healthy light source is very important!
The case map is too horrified and will not let go...
What is a healthy light source?
What kind of light source is called healthy?
A healthy light source is usually defined as: all visible light that has been able to withstand human evolution, has no damage to the body, is harmless to vision, and makes humans feel happy.
We often feel that the sun at 8 am and 5 pm is more comfortable. The strong light at noon can make people feel glaring and uncomfortable. This is unhealthy for people. Therefore, the sun is not a complete healthy light source, but it is necessary to consider the time period.
Healthy light sources can often be evaluated from the following aspects:
1 wave length
Determine the color of light, such as three primary colors: red light (630nm) green light (550nm) blue light (450nm);
2 strength
Commonly used light intensity (Cd) and illuminance (lx) to measure, the international and domestic lighting products have a clear definition of light intensity, too strong and too weak for eyesight will cause damage;
3 color temperature
Determine the basic color of light (there are more white, warm white, cool white, etc.), the color temperature that the human eye can perceive ranges from 1500K to 12000K. The color temperature needs to be compatible with the environment. For example, in the hospital, cold white light makes the patient feel irritated, while warm white light makes the patient feel more comfortable (important factor).
4 color development
Color rendering refers to the characteristics of different colors when light sources of different spectra are illuminated on objects of the same color. The color rendering index (Ra) is usually used to indicate the color rendering of a light source. There are not more than 75 colors on the market, and the real 80 is very small. In the laboratory, a light source with a color rendering of 97 has been developed. When the light effect is not greatly reduced, the color rendering property is greatly improved;
How can I achieve a healthy light source?
So how do you make a very cost-effective health light source with or without cost? Let's see what methods are available!
Color matching
The color map can be used to analyze and adjust the color temperature during the color matching process. Take the cold light of the main light source on the market as an example:
Figure: Cool white light spectrum
It can be seen from the spectrogram that the blue light of the cool white light is strong, the red light is weak, and the color temperature is about 6500-7000K, which is slightly whiter for the human eye.
Another common light - warm white light, as shown below:
Figure: Warm white light spectrum
Compared with the cool white light, the warm blue light is relatively weaker, the red and yellow are relatively prominent, the color temperature of the upper right picture is about 1700-2000K, and the color temperature of the upper left picture is about 3500K.
It can be seen that judging the color temperature by the spectrum is an important criterion for measuring the light source.
The combination of phosphor, glue and chip is the key to making a cost-effective healthy light source with or without cost.
Optimized packaging technology
The four material factors that affect the light quality and effect of the light source during the packaging process are chips, brackets, phosphors, and sealants. The complexity of the package is that the four are interrelated and mutually influential, which requires us to consider the following techniques in the package:
1. Chip and bracket matching
Any bracket is designed for a specific chip that matches the chip;
2. Matching of chip and phosphor
The mechanism of chip luminescence is to use the blue light emitted by the chip to excite the phosphor to make the light we need. The chip emits light at a wavelength that is effective to excite the phosphor.
3. Matching of chip and glue
The light guiding property, compactness and other properties of the glue will affect the color drift, dead light, water vapor, blackening and other factors. In addition, chips, especially high-power chips, often need to dissipate heat from top to bottom. Therefore, the heat dissipation of the glue should be considered in the package, and whether it is matched with the chip.
4. Matching of phosphor and light source quality
Poor phosphor ratios can cause the light source to appear in colors that we don't need to see, or the color is not accurate enough and not wide enough.
For example, using a 450 nm blue chip and a phosphor with an effective excitation of 454 nm, the wavelength difference between the two is 4 nm, which results in a loss of 2%-5% of the luminous efficiency of the phosphor;
5. Matching of different materials and different processes
Packaging technology is the key to achieving a healthy light source.
Imitating the spectrum of sunlight
Generally, the human eye is more adapted to the solar spectrum.
Solar spectrum range: 400-750nm, green light is strong, red light is weak
Solar white temperature: 3500K-5500K,
Color rendering: 85 or more.
Compared with sunlight, the biggest soft rib of LED light lies in the huge loss of blue and green parts.
Figure: Solar spectrum
Figure: Spectrum of LED light source (blue and green missing)
The good news is that the health spectrum that is very close to sunlight has been studied in the experiment:
The problem of missing blue and green light in the LED light source can be compensated by adding blue-green phosphor. In fact, the addition of phosphors has been learned. Experiments have shown that the amount of blue-green powder has a significant effect on the color temperature, index and light efficiency of COB LED package light source:
Most of the light sources on the market are cold white, and the color temperature is not conducive to the living environment. The LED light source without visual system damage adopts a variety of phosphor matching in the package, and the green phosphor is added, and the finished product has improved in color temperature, color development and light effect.
It can be seen that finding a suitable amount of phosphor through the COB experiment can achieve a suitable color temperature of the light source, and improve the color rendering index and light efficiency of the light source.
The design of the light source should match the environment
The picture below shows the lighting design of McDonald's. The light is close to warm white, which makes people feel appetizing, very comfortable and relaxed. At the same time, the intensity of the light source conforms to the universal standard, so that the light is effectively illuminated on the table, but it is not glaring.
Picture: McDonald's Lighting Design
Therefore, in the design of the light source, it is necessary to consider different environments and places (such as: hospitals, classrooms, shopping malls, etc.) to make the light source effect meet the environmental requirements.
to sum up
1. Healthy light sources have important significance for human health;
2. Through the blending of LED encapsulant and various phosphors, a simulated solar health spectrum can be obtained;
3. The design of a healthy light source needs to consider the pertinence of its use;
4. The development of human health light source packaging technology may become a widely optimistic development direction in the next five-year cycle.
The development of healthy light source technology is not only the demand of the market, but also the trend of industry development.
Busbar Marine Terminal Block,Screw Busbar Insulators,Electrical Drum Support Busbar,Battery Support Busbar
Wonke Electric CO.,Ltd. , https://www.wkdq-electric.com