How to buy LED plant lamp beads

The development of LED is attributed to the mass production of Blue chip by Japan Riya Company in 1993. The emergence of Blue LED opened up a new field of human lighting. With the development of LED technology, LED plant lights applied in agricultural planting also triggered an era of innovation, and the quality of LED plant lights is closely related to led strip lights. So how to buy a good led strip light has become a top priority, the following article will analyze from all aspects, to help you have a clearer and deeper understanding of LED, so as to choose the LED plant lamp bead suitable for the enterprise products.

First, LED production process

LED chip production process includes two aspects, one is epitaxial wafer growth, the other is chip production.

LED epitaxial wafer growth technology mainly adopts organometrics chemical vapor deposition (MOCVD) to produce epitaxial wafer with semiconductor luminescence characteristics. Epitaxial wafer is the raw material for manufacturing LED chip. The following figure shows the production process of epitaxial wafer with sapphire substrate:

LED chip is made of epitaxial chip, chip is to provide flexible led strip light packaging device, is the premise of led strip light quality, the following is the LED chip production process:

led strip light encapsulation is according to the application requirements of led strip light, the manufacturing process of chip packaging on the corresponding support, LED encapsulation decided the led strip light ratio, which is a key link in the process quality of led strip light, LED the manufacturing process of complex, high technical content, in the whole process, as long as a link to a problem, the led strip light lose quality performance.

Two, LED technical parameters

In the production process, the same batch of raw materials in the production process due to various reasons lead to the packaging of the finished products will have different quality, simple from the appearance and process can not be distinguished, need to measure technical support, for the application of plant lamp, need to choose according to the parameters of plant light spectrum indicators.

Plant lamp is parameterized spectrum technology products, plant lamp light bead and lighting lamp bead on parameters expression is different, the current LED packaging companies provide light bead parameters cannot be suitable for the design of the plant light requirements, this problem is a result of plant light spectrum testing technology and plant light spectrum with parameters due to the particularity of.

Plant lamp manufacturing enterprises in the purchase of lamp beads, need to transform the lighting parameters of the lamp into the spectral parameters of plant lamp beads, this parameter transformation process we call the spectral parameterization of plant lamp beads, the design of plant lamp products must use parameterized lamp parameters, otherwise there is no basis to achieve the design indicators.

The expression of the lamp bead after parameterization is very intuitive, such as:

QE1.042/645 nm / 3.28 V / 60 ma / 2835

Many technical products are parametric products, such as computer graphics cards, whose stated parameters represent the performance and price of the graphics card.

1. Radiated power:

The radiation power of led strip lights is the main index to determine the performance of plant lamp products. The greater the radiation power, the higher the PPF value of the lamp beads, the better the radiation performance of the plant lamp.

The radiation power of the lamp bead is related to the chip area, which is obtained by multiplying the length and width of the chip. The larger the chip area, the higher the radiation power.

The radiation power of led strip light is decided by chip radiation power grade and price, chip radiation power is bigger, the price is more expensive.

Take the chip of Xiamen SAN ‘an as an example, S-23BBMUP-C*******. The chip size is 23X10mil, and the core has four radiated power levels (@20mA).

There is a difference of 8mW between the radiant power of D24 and D27, that is to say, the PPF value of the lamp bead made by the chip of the same size is different, so it is necessary to know the radiant power level of the chip when purchasing.

2, power consumption

led strip lights are divided into power levels according to the size of the current specification, the larger the current specification, the higher the power of the chip, but the greater the heat of the chip.

Different current specifications of the chip is packaged into different size specifications, such as: 2835,5730,3030, etc., the selection of different packaging specifications is based on the structural design requirements of the plant lamp, usually, the low power of the chip high efficiency and low heat.

3. Radiation efficiency

The radiation efficiency of the lamp bead = radiation power/power consumption *100%, the radiation efficiency value is less than 100%.

The radiative efficiency is the proportion of the radiated power generated per watt of electricity consumed, and the greater the radiative efficiency, the better.

Radiation efficiency is limited by semiconductor material production technology, as well as packaging technology and heat dissipation technology. The main reasons affecting radiation efficiency are as follows:

Influence of chip manufacturing quality: different production equipment and chip technology affect the radiation efficiency of chip, and choosing brand chip manufacturer is an effective method.

Bracket material: there are aluminum bracket, brass bracket, copper bracket on the market at present, aluminum bracket is the cheapest, copper bracket is the most expensive, even copper bracket, silver plating quality also has high and low points; Packaging materials also include a variety of fixed and filled adhesive qualities.

The quality of white and rare earth beads is also affected by the quality of phosphors, the high quality phosphors have low light decay; The phosphors of white light are mainly divided into aluminate and silicate, the performance of aluminate is better than that of silicate, and the most representative of aluminate is YAG. YAG has stable performance and low light decline, and the chemical stability of silicate is poor, but its brightness is higher than that of YAG.

Welding wire material: in addition to flip chip and CSP packages, most of the lamp bead encapsulation is to use gold wire welding technology, the chip electrode connected with stents, currently on the market has alloy wire, gold line two kinds, gold line, the best gold thread according to the thickness and points 0.7, 0.9, 1.0, 1.2, etc, gold wire is thick, the lower the heat group, the longer the life of lamp bead.

4, PPF value: the PPF of the lamp needs special software to calculate. The power of the plant lamp is determined according to the PPF value of the LED lamp. If the packaging enterprise can not provide the PPF value of the lamp, it can not become a qualified supplier of the plant lamp.

5. MPF value: the measured value of photon flux in the wavelength range of 380nm-800nm, in umol/s. For monochromatic beads, MPF=PPF, and for fluorescent beads encapsulated, the MPF value is greater than PPF, so both MPF and PPF should be marked in the parameter expression of fluorescent beads encapsulated.

6. QE value: QE value is the PPF value per watt, which is derived from the spectral parameters of the plant lamp bulb, and the unit is umol/J. This parameter is the comprehensive index of the plant lamp bulb, and also the most important performance comparison index. QE value is the parameter that must be marked after the spectral parameterization of the lamp bulb. Measurement errors can lead to distortion of QE values.

7, radiation ratio: in the definition of the band range of the mutual relationship between the amount of radiation, expressed in two ways.

Radiation content: the percentage of a certain band in the total radiation amount. Radiation content is the weight of the radiation amount of a certain band in the total radiation amount.

Emissivity: The ratio between two wavebands. Emissivity is the unit weight of each other, usually R: B and R: FR.

Radiation ratio is only effective for white light and rare earth process, monochromatic light has no radiation ratio.

8, voltage division specification: is the chip voltage division, such as 3.0V-3.15V, for the series and parallel connection of the light source, voltage division control within 0.15V, so that the current distribution of each string of light source is uniform, is conducive to improving the life of the light source.

9. Color temperature grading: for the color separation using white light beads, the packing factory needs to provide the BIN code of color temperature. The plant lamp using white light has relatively no strict requirements for color separation, and the use of color BIN can be appropriately relaxed.

Iii. Evaluation rules

1. Evaluation rules for spectral parameters of lamp beads

The radiation efficiency of lamp beads is the basis of spectral parameters, and the comparison of PPF, MPF and QE is meaningful only when the radiation efficiency is the same.

QE tends to be distorted with the increase of green radiation content. For monochromatic light beads, the larger QE is, the better.

Currently, the QE of the led strip light has not exceeded 2.2umol/J, and the QE parameter of any test analysis is close to this upper limit. It is necessary to evaluate the error between the test method and the measured data.

In the future, when the LED lamp QE exceeds 2.2umol/J, LED plant lamp will enter the environment of comprehensive application, and other light sources will gradually withdraw from application. The plant light spectrum technology takes the QE reaching 3.0umol/J as the research goal in the next few years.

2, led strip lights in plant lamp application rules

led strip light, drive current best don’t more than specifications current, the current chip ampere rating is already close to the chip under limit, although can by improving the heat to increase the drive current, high PPF value, at the same time, lamp bead power also increases, increase of PPF and power is not linear, the result is QE value lower instead.

The mechanism of this phenomenon is that after increasing the current, the recombination rate of electronic holes decreases, the lattice defects of the chip begin to highlight, and the heating of the chip increases, leading to the decrease of the radiation efficiency of the chip, the increase of power consumption is higher than the increase of PPF, and the QE value of the plant lamp decreases.

A good design is to find the most priority between the heat dissipation index and radiation efficiency of the lamp, rather than using expensive radiator to increase the power of the light source, the result is often to increase the power and reduce the QE index.

I often see the phenomenon of turning good beads into bad products. Some plant lamps change the QE1.3 of the beads into QE0.8 of the plant lamp. If the QE of the plant lamp is below 0.7, I suggest switching to cheaper headlamps.

Tip: Reducing the drive current of the lamp bead is an effective way to achieve a higher QE value.

LED lamp is a current device, try to choose a lower junction voltage (Vf), can improve the QE value, lower Vf can also reduce the heat of the lamp, high power plant lamp Vf selection is particularly important.

The radiation efficiency of lamp bead decides the calorific value of plant lamp, the heating power of lamp bead = (1- radiation efficiency ratio) * electric power.

You can test the actual thermal power of the lamp to check whether the radiation efficiency value is correct.

On the premise of spectral design ability, the discontinuous spectrum with monochrome bead ratio can be guaranteed in light decline index. When using continuous spectrum beads, the light decay index and blue shift index are the first factors to be considered, but the continuous spectrum beads have advantages in cost performance.

It is necessary to pay attention to the indicators of R: B and R: FR in the continuous spectrum. At the same time, too much green radiation will cause QE distortion.

The measurement parameters of the lamp bead are limited by the limit parameters. Any test data close to the limit parameters need to be evaluated by a professional evaluation agency and should not be trusted easily.

The abnormality of led strip light measurement parameters is mainly to observe the radiation efficiency and QE value, which is more intuitive, and the abnormality of these two indicators needs to be re-measured.

I am most worried about the measurement error and false label of LED chip. I have always stressed that plant lamp is a parameterized product, and what plant lamp sells is the spectral parameters. If the spectral parameters are distorted, it is impossible to talk about the planting effect.

For the measurement error and virtual standard parameters, MY spectral design theory has set a detection link, that is, XD factor. Through XD factor, we can measure the illumination value and convert it into PPFD with the XD factor, which can be used to verify whether QE is accurate. This is the innovation point of our plant light spectrum technology. This closed-loop design theory ensures the accuracy of plant light spectrum parameters more reliably.

3. Cost performance of led strip light procurement

For the procurement of lamp beads, the most concerned is the cost performance of lamp beads, usually people compare the price of similar packaging, we provide a lamp cost-effective calculation formula, can easily compare the pros and cons of product prices.

The price/performance ratio of the lamp is equal to QE/ price, which tells you how much QE you get per unit price.

High cost performance means high QE value per unit price

For SMD packages, the recommended price is Angle.

For COB packages, the price is recommended in yuan.

Master the above knowledge points, the concept of parametric plant lamp will be more clear, I believe that the procurement and evaluation of plant lamp beads will be of great help, so as to improve the market competitiveness of plant lamp.

Plant lamp is the product of spectrum technology parameterization, professional spectrum parameters should be used to describe the product and marketing, so that those fake and shoddy products can not flood the market, and jointly maintain the healthy development of plant lamp industry.

For more products please click: Customized Led strip light