How LED industrial lighting develops in industrial 4.0 era?

Introduction: Lighting is an indispensable part of the realization of a smart factory. So, we can’t help but ask, what is the development of industrial lighting today? Will it change in response to changes in the times?

There are no workers in the automated factory’s workshop, the machines are running automatically… It looks like this is no longer just a dream. As early as 2015, the Chinese government announced the “China Made 2025” Chinese version of “Industry 4.0”. The entire system consists of three parts: smart products, smart production, and smart factories. Lighting is an indispensable part of the realization of smart factories. So, we can’t help but ask, what is the development of industrial lighting today? Will it change in response to changes in the times?

LED industrial lighting, big attraction market

In fact, industrial lighting seems to be only a relatively small and low-key member of the entire lighting family compared to home and commercial lighting; it is a high-frequency vocabulary in media reports such as plant factories, automotive lighting, infrared-ultraviolet LEDs, and optical communications. , Industrial lighting is relatively unpopular, but this will not affect its charm in the slightest – in the LED replacement demand continues to heat up and government subsidies support, the industrial lighting market grows faster.

According to the survey results of relevant market research institutions, the global LED industrial lighting market in 2016 reached US$2.932 billion and will grow at a rate of over 16% per year. It is expected to reach US$3.935 billion by 2018 and the market scale will be 2020. Up to 5.204 billion U.S. dollars. China’s industrial electricity consumption has accounted for more than 70% of the total electricity consumption in the society. The demand for industrial energy conservation is strong. The huge market space also makes China’s LED industrial lighting penetration rate expected to further increase. According to forecasts, in 2015, LED products accounted for only 6% of the entire industrial lighting products, it is estimated that in 2035, the LED market penetration will reach 86%.

At present, LED industrial lighting users are mainly foreign-funded enterprises, state-owned enterprises and some outstanding private enterprises. Among them, foreign-funded enterprises have advanced management and environmental protection concepts, accepting LED earlier, and relatively clear requirements on the knowledge and technical parameters of LED lighting products, which are the enterprises that started to use them early; and the state-owned enterprises’ central enterprises’ policies for energy saving and emission reduction of the corresponding countries. Also began to use LED replacement light source; some outstanding private enterprises in order to control production costs and improve the overall competitiveness of enterprises, but also gradually accept the LED industrial lighting.

Product performance has gradually approached the metal halide lamp?

Despite good market prospects, the industrial lighting field is still considered to be the last LED lighting application field. At present, the application of LED in industrial lighting is mainly for small and medium power lighting fixtures. In the field of high-power lighting applications, metal halide lamps are relatively cost-effective relative to high-power LED light sources, and LED lighting is temporarily unable to replace them with overwhelming advantages.

However, it is gratifying that in March 2017, the US Department of Energy’s CALiPER (commercially viable LED product evaluation) project team announced the LED industrial lighting according to the data of the LED lighting product database of LED lighting products. The product brief shows:

1. The luminous efficiency of LED industrial lighting products is generally higher than that of existing products. Among the LED lighting products with LED lighting facts, 23% LED High Bay,LED Linear high bay have a luminous efficiency of more than 130lm/W. There are 5% higher than 150lm/W and 1% higher than 175lm/W. These exceed the average luminous power of fluorescent lamps and metal halide lamps and their luminous power is only 70 to 90 lm/w.

2. In general, LED industrial lighting products have certain advantages over similar competing products. Among the statistical products, 50% of the luminous flux is between 11,000 and 22,000 lm. In addition, the luminous flux of more than 150 products exceeds 50,000 lm, so the average luminous flux is 18,000 lm. The power of these LED products is equivalent to 1000W metal halide lamps.

3. In terms of color temperature and power, the performance of LED products is no different from that of traditional metal halide lamps and fluorescent lamps. 65% of statistical products, color rendering index in 80s, the vast majority of industrial products. Half of the statistical products have a color temperature of 5000K or higher, which is higher than that of traditional industrial lighting fixtures. These high color temperature products have higher luminous power than other types of products.

Of course, this is just the data of industrial lighting products in the United States. What is the level of technological development of domestic LED industrial lighting products? There are no relevant reports yet, but perhaps we can find the answer at the Guangzhou International Lighting Fair which was highlighted in June this year.

Product trends will gradually become modular and intelligent?

After all, industrial lighting products, because their needs are relatively simple, and more to meet the bright, uniform effect, so this type of product is relatively less innovative. Recently, however, industrial products have made breakthroughs in functions and applications. The design of the installation module (electricity)+lighting module has been adopted. The lighting module has narrow, medium, wide, and bi-directional polarization designs and can be equipped with human sensors. , DALI, daylight sensory adjustment and other functions.

Furthermore, industry analysts have pointed out that smart lighting will become the “ETC” for lighting industry practitioners to enter the industrial lighting field. Because the energy-saving effect of intelligent LED lighting system can make industrial lighting under long-term use, more cost-recovery competitiveness than home lighting, there are enough incentives to urge owners to replace the original lighting products.

Li Jinglfuse senior technical marketing engineer You Yuehao had different opinions. He believes that, at this stage, the existing plant to introduce LED smart lighting, there is no substantial benefits, for the lighting of the existing plant, only the need for on-site personnel control, it is not necessary to import intelligent control functions. However, if the new factory is built, the introduction of the concept of Industry 4.0 will have substantial significance.

indoor warehouse lighting

How to choose the most suitable LED lighting for warehouse?

indoor warehouse lighting

Factory lighting includes:

workshop lighting, warehouse lighting, office lighting, factory lighting, equipment lighting, and other ancillary lighting. How to choose the most suitable LED lighting for industrial warehouse?It must be LED linear high bay light.

In the design of warehouse lighting, according to the visual requirements, warehouse operations and environmental conditions, through the choice and configuration of LED lamps, the working area space has reasonable illumination, color rendering and appropriate brightness distribution and comfortable visual environment.

We can first consider these elements:

1) Energy-saving: Intelligent control of the lighting system is implemented, and dual-channel lighting of the warehouse is adopted. During the day, one road can be closed and two roads can be opened at night;

2) Safety: Lighting fixtures with dust-proof, anti-corrosion and anti-riot properties should be used to ensure the safe operation of the lamps;

3) Long-life: The warehouse should not change the lamps frequently, avoid increasing the cost of the later period, and choose lamps with long life and high stability.

4) Warehouse height: 4-6 meters of low-level warehouse, 6-15 meters of middle warehouse, and 15 meters of special high-rise warehouse;

5) Shelf height: The shelf height of the middle warehouse is generally 2 meters, while that of the middle warehouse is generally 8 meters.

6) Illumination requirements: in order to clearly identify the goods and labels, the minimum brightness to the ground must not be less than 80 lux;

1-3 elements relatively speaking, as long as the choice of honest merchants LED products, according to the parameters agreed in the contract, there will be no basic problems. If it is a three-year warranty product brand recommended light source wafer, five-year warranty products using Bridgelux, Epistar,Cree and other brands, more than five years warranty products the driver using Meanwell or Inventronics.
The most important thing is to base on the 4-5 elements, that is, to lay out the position of the light according to the height of the shelf and the placement position, to ensure that each channel has enough light, and to pass the professional lighting fixture simulation software. , Analysis and calculation of the need for how much power LED lights, in order to achieve the illuminance requirements of element 6.

We use the most common 4-6m warehouse height to see a case where the customer requires 120lux of ground illumination. We recommend a 90×110° LED linear high bay lamp, 80W to the ground can reach 160lux, and the span between lamp and lamp is 5- Between 6 meters.


The most common one is a 9-12m warehouse. For example, the height of a warehouse in Amazon is 12 meters and the height of the shelf is 8 meters. They require energy saving, safety, and long service life of the lamps. Due to the high shelf, the lighting at the top of the shelf is also required. To be very good, we recommend 150W LED linear high bay light, 30×70°, installation height of lamp: 9.5m, 200lux from ground height 75cm, 350lux from ground 6m height, span between lamp and lamp 6 meters.

When determining the lighting plan for the warehouse, special requirements for warehouse lighting of different types of buildings should be considered, and the relationship between lighting and natural lighting should be well handled. High-efficiency light source lamps and lanterns should be used, construction funds should be used rationally, and warehouse lighting quality should be improved.

After reading these programs, I believe you must know how to choose the most suitable for your warehouse lights. You can also contact us at any time to help you out with a plan that suits you better.


built-in motion sensor led high bay

Use microwave sensor lighting should pay attention to matters

built-in motion sensor led high bay

Installation distance:

Microwave sensors LED Lighting are more and more widely used in underground parking lots, stairways and office spaces due to their high sensitivity and installation concealment.

Under normal circumstances, the human body microwave induction lamp, the drive circuit actively emits microwave signals with a frequency of 5.8 GHz. When the outside world has a moving object, it is based on the Doppler effect (the reception frequency becomes higher when the wave moves closer to the observer when the wave source moves closer. When the wave source is far away from the observer, the reception frequency becomes lower), and the signal is fed back to the transmitting device, triggering the luminaire to change its state from light to full light. However, when multiple microwave sensor lamps are installed together, if the lamps are too close together, the radar signal from the A lamp may be received by the B lamp, causing the feedback signal received by the B lamp to not be the signal returned by itself. However, it is the emission signal of the A lamp, and the form of signal interference appears as mutual superimposition or mutual reduction, so that the induction switches interfere with each other.


Common malfunctions in the interference state are:

Always on (the device is always on)
Often dark (device cannot be triggered)
Short sensing distance
So, when installing multiple microwave sensor lights, how much appropriate spacing between the lights?
After many practical tests, the interval between the two luminaires is kept at 1.8 meters or more, and there is basically no interference.

Application Environment:

Do not cover the sensor with a metal object.
The microwave sensor is installed in the metal space to reduce the sensing range of the sensor.
The metal object will shield the radar signal and use the object to block the sensor. Then the sensor signal is shielded.

Common malfunctions in the interference state include: no induction effect, or very short sensing distance.


cct adjustable led panel

How much do you know about the quality of the LED panel light?

cct adjustable led panel

The key factor affecting the quality of the panel light: light guide plate

With the replacement of traditional grid lights by led panel lights, the quality and appearance of led panel lights have received unprecedented attention. However, the price of led panel lights on the market is not the same, as low as several US dollars, and prices as high as 20-30 US dollars. What is the reason for the huge price difference?

The price is decided by venues, labor, materials, market and other factors. Today we will talk about the impact of light guide plates on the quality and price of panel lights. First of all: led panel light consists of a light guide plate, a diffuser plate, a reflective film, an aluminum profile, a power supply, and a led lamp bead. Among them, the light guide plate plays a decisive role in the light effect of the panel light, and the diffuser plate plays a role in the softness and evenness of the light of the panel light.

Type of light guide plate:

The light guide plate is divided into PS, PMMA, MS from the material


The advantages and disadvantages of PS light guide plate:

The advantages of PS are that the chemical stability, thermal stability, optical transmission characteristics, strong refraction, and electrical insulation properties are all very stable. Available in wet environments.

The disadvantage is that it is brittle, it is easily yellowed and brittle, and it is not heat-resistant. Can only be used in environments below 70°C. The refractive index is lower than acrylic. In general, lighting is suitable for use in indoor locations at mid-latitudes.

The advantages and disadvantages of PMMA light guide plate:

PMMA is abbreviation of poly methyl methacrylate, also known as plexiglass or acrylic, a bit of weather resistance, heat resistance, not spontaneous combustion, light transmission rate of 90%, the light guide plate is suitable for higher brightness and light efficiency requirements Panel light products.
The disadvantage is that PMMA is brittle and costly. The size of acrylic light guides such as Mitsubishi is generally 3/4/6/8/10/12mm, and irregular sizes such as 1/2/3.8mm are rarely found. The first is 1-2mm of acrylic thin and easy to use. Crisp, 3.8mm, etc. Acrylic plates are non-standard, and the customization cost is high. Secondly, the acrylic plate is large in static electricity, and the dust is easily adsorbed. A 100,000 dust-free workshop is required to complete the assembly. However, PMMA light guide plates are favored by non-standard size panel lamp manufacturers because of their good light efficiency, strong weather resistance, low light attenuation, and environmental protection.

The advantages and disadvantages of MS light guide plate:

The transparency and toughness of MS is better than that of PS (through-benzene and benzene). The MS material mainly replaces acrylic transparency by 92% and haze by 2%. Toughness theory should be better than acrylic, and hardness is softer than acrylic. It is a combination of PS and PMMA.

Optical performance is good: Compared with the traditional light guide plate plus the printed design, it has higher uniformity and brightness.

Excellent dimensional stability: The use of MS material to produce micro-structured light guide plates with less warpage than conventional PMMA materials and excellent dimensional stability

Thin profile: With a thickness of 2 mm & 3 mm, it replaces the conventional 4 mm to 6 mm light guide plate.


TUBU has high light efficiency, color rendering index 95, anti-glare,color change and other series of panel lights, if you want to learn more about panel lights, please feel free to contact us(



built-in motion sensor led high bay

Analysis of Industrial Lighting

built-in motion sensor led high bay

Industrial lighting

Industrial lighting design includes indoor lighting, outdoor lighting, stations, field lighting, underground lighting, road lighting, security lighting, obstacle lighting and so on.

Design Points

Range and type

The factory is a place for production of established products, generally consisting of factory buildings, offices and other ancillary rooms, various types of outdoor devices, stations, fields, and roads.
(1) Indoor lighting: internal lighting of auxiliary lighting for interior lighting and office buildings.
(2) Outdoor Device Lighting: Lighting for various outdoor devices. For example, the open-air operations of the shipbuilding industry, kettles, tanks, reaction towers of petrochemical companies, rotary kiln of building materials companies, belt corridors, blast furnace furnaces of metallurgical enterprises, walkways, platforms, gas cabinets of power stations, total pressure reduction Substation outdoor lighting, distribution equipment, outdoor pump station cooling tower (tower) and outdoor ventilation and dust removal equipment lighting.

(3) Station lighting: Lighting installed at stations, railway marshalling yards, parking lots, open storage yards, etc.
(4) Underground lighting: lighting in basements, cable tunnels, integrated corridors and tunnels.
(5) Road lighting: lighting of factory roads and other roads.
(6) Guard lighting: Lighting along the perimeter of the factory area and around the security area around key locations.
(7) Obstruction lighting: There are special high-rise buildings and structures such as chimneys in the factory area. According to regional aviation conditions, the signs need to be installed according to relevant regulations.
This chapter focuses on the interior lighting of the factory. For other lighting, see the relevant section of the lighting design manual.

Industrial factory features

1. Features of industrial plants
Industrial plants can be divided into single-storey industrial buildings and multi-storey industrial buildings according to their building structure types. The vast majority of multi-storey industrial buildings are found in the light industry, electronics, instrumentation, communications, and pharmaceutical industries. The floors of such plants are generally not very high. The lighting design is similar to the common scientific research laboratory buildings, and most of them use fluorescent lighting solutions. The production plants in the mechanical processing, metallurgy, and textile industries are generally single-layer industrial buildings, and according to the needs of production, there are more multi-span single-story industrial plants, that is, multi-span plant buildings that are arranged next to each other in parallel. The needs can be the same or different.
The single-storey factory building determines the building width (span) and length on the basis of meeting the requirements of a certain building module.
And height. The span of factory building B is generally 6, 9, 12, 15, 18, 21, 24, 27, 30, 36m… The length of the factory building is between tens of meters and hundreds of meters. The height of the factory building is 5 to 6 meters in height, 30 to 40 meters in height, and even higher. The span and height of the plant are the main factors considered in the design of the plant lighting. In addition, according to industrial production continuity and the need for product transportation between sections, most industrial plants are equipped with cranes, which can be light weights ranging from 3 to 5 tons, and can reach several hundred tons. (Currently, the weight of a single crane in the machinery industry Up to 800t). Therefore, factory lighting is usually implemented with luminaires mounted on roof trusses.
2. Classification of industrial plants
According to the characteristics of product production, industrial plants can be roughly divided into the following three types.
(1) General production plants: Factory buildings under normal conditions.
(2) Explosion and fire risk production plants: Factory buildings that normally produce or store explosive and fire hazards.
(3) Production plants in harsh environments: production plants that are dusty, humid, high-temperature or have steam, vibration, smoke, acid-base corrosive gases or substances, and radioactive substances.
According to the above classification, factory lighting design should be strictly followed in accordance with the different production conditions.

General requirements

Factory lighting should follow the following general principles for design.
1. The choice of lighting
(1) For high illumination requirements, the density of working positions is not large, and mixed lighting should be adopted in places where general illumination is not reasonable.
(2) The illumination of the work is not required to be high, or when it is not suitable to install local lighting when the technical conditions of production are limited, or when the mixed lighting is unreasonable, general lighting should be used alone.
(3) Partial general lighting can be used when a work area needs to be higher than general lighting illumination.
(4) Partial lighting should be added when the general illumination of the partition cannot meet the illumination requirements.
(5) Local lighting should not be installed in the work area.
2. Illumination standard
The illuminance value of factory lighting design should be selected according to the national standard GB 50034-2004 “architectural lighting design standards”. The standard specifies the illuminance values ​​of general lighting for 16 industrial buildings. The illuminance standards for more specific workplaces in various factories should also be in accordance with relevant industry regulations.
3. Lighting quality
Lighting quality is a sign of measuring the merits of a factory’s lighting design. It mainly includes the following:
(1) Select lamps with high efficiency and suitable light distribution curve. According to the luminaire hanging height on the plant house frame index according to the chamber, the value of the selected light fixtures.
When RI = 0.5 ~ 0.8, narrow light fixtures should be used;
When RI = 0.8 ~ 1.65, it is advisable to use medium light fixtures;
When RI=1.65~5, wide light fixtures should be used.
(2) Select the lighting source with appropriate color temperature and color rendering index to meet production requirements.
(3) To achieve the specified illuminance uniformity: The illumination intensity of the general illumination in the operation area should not be less than 0.7, and the illuminance uniformity around the operation area should not be less than 0.5.
(4) Meet the quality requirements of the direct glare limitation of lighting: Uniform glare value (UGR) is in accordance with the provisions of GB 50034-2004. That is, the general allowable value is 22 and the fine processing value is 19.
(5) Take measures to reduce the impact of voltage fluctuations and voltage flicker on lighting and prevent stroboscopic effects.
(6) The lighting device should work under the allowable working voltage. In the place where metal halide lamps and high pressure sodium lamps are used, compensation capacitors should be used to increase their power factor.

Lighting method

Lighting can be divided into: general lighting, district general lighting, local lighting and hybrid lighting. Its applicable principle should meet the following requirements:
First, it is advisable to use general lighting when unsuitable for installation of local lighting or mixed lighting is unreasonable;
Second, when a work area needs to be higher than the general lighting illumination, sub-zone general lighting can be used;
Third, for the higher illumination requirements, the density of the working position is not large, and the installation of general lighting is not reasonable places, should adopt hybrid lighting;
Fourth, local lighting should not be installed in a workplace.
Lighting category editing
Can be divided into: normal lighting, emergency lighting, duty lighting, security lighting and obstacle lighting. Among them, emergency lighting includes spare lighting, safety lighting, and evacuation lighting, and its applicable principle should meet the following requirements:
1. When the normal lighting is extinguished due to a fault, equipment lighting shall be installed in places where it is necessary to ensure normal work or activities continue;
2. When normal lighting is extinguished due to a fault, safe lighting shall be installed at places where it is necessary to ensure the safety of personnel at risk.
3. When normal lighting is extinguished due to a fault, evacuation lighting shall be installed on the exits and passages that need to ensure the safe evacuation of personnel;
Fourth, on-duty lighting should use part of normal lighting that can be controlled individually or use part or all of emergency lighting;
5. Security lighting should be installed within the guards as required;
6. The installation of obstacle lighting should strictly comply with the relevant regulations of the aviation or transportation departments in the region.

Select lighting

When selecting the type of lamp according to environmental conditions, attention should be paid to environmental temperature, humidity, vibration, pollution, dust, corrosion, explosion and fire hazard media. The following three environmental conditions to choose lamps.
First, the general industrial plant lighting options
(1) In the normal environment (heating or non-heating), open type luminaires are generally used.
(2) Lamps that contain a lot of dust, but are not exposed to explosion and fire hazards, use lamps that are compatible with the amount of dust.
The amount of dust in a dusty environment is measured as the concentration in air (mg/m3) or the amount of sedimentation [mg/(m2·d)].
For general dusty environments, dust-proof (IPSX) lamps should be used. For dusty environments or general dusty environments where conductive dust is present, dust-tight (IP6X) lamps should be used. IP65 rated lamps should be used for conductive fiber (such as carbon fiber) environment. For lamps that are frequently flushed with water, no less than IP65 rated lamps should be used.
Clean rooms are areas within the factory that require strict control of environmental conditions. The main function of lighting is to make the work activities clearly visible, thus forming safe, comfortable and effective working conditions.

the advantages and disadvantages of round high bay and linear high bay

Contrast LED Linear High Bay and UFO LED High Bay

Contrast temperature of the shell

the advantages and disadvantages of round high bay and linear high bay

TUBU’S LED Linear High Bay VS Round High Bay

LED Linear High Bay

Ambient temperature is 30°C, the case temperature is up to 53.1°C.

Round high bay

Ambient temperature is 30°C, the case temperature is up to 73°C.

From the above test results, we can get a conclusion that the light attenuation of linear high bay is smaller than that high bay lamp.

Comparison of light distribution curves

rectangular lightround light distribution

For Linear high bay the light distribution is rectangular.            For Round high bay the light distribution is round.

LED Linear high bay fixtures can be applied to corridors, warehouse shelves and other places to achieve uniform lighting effects. The application of circular LED high bay to these sites will not achieve the same effect, and even cause a waste of light, eventually leading to increased energy costs.
The advantage of the circular LED high bay is high installation efficiency and lower labor costs, which can be applied to open spaces and the places without special requirements.

You can choose according to your needs.

If you want to know more about LED High Bay Fixture information, please visit our Industrial lighting catalogue.


led sunlight fixtures spectrum

Is Ra=100 really the best color rendering?

led sunlight fixtures spectrum


Color is one of the feelings of people. It is always related to the individual subjective experience of the observer. The feeling that everyone sees a color is difficult for others to know. So the study of color is always full of mysterious imagination. At the same time, colors have made the world colorful, and visual arts, image display and transmission, textile printing and dyeing, and color printing are all inseparable from the study of color. Therefore, the study of color and the objective quantitative description of color have become the object of study for many scientists.

In 1664 Newton used a prism to disperse white sunlight into a spectrum of different shades, laying the physical foundation for light color. In 1860, Maxwell used different intensity red, yellow and green light to match the light from white light to various colors, which laid the foundation for trichromatic colorimetry. On this basis, the International Commission on Illumination established the CIE colorimetric system in 1931 and continued to improve it. CIE color systems are now widely used to quantitatively express the color of light.

Color can not be separated from lighting, only in the light of the object is possible to show color, and the color of light has a very great influence on people’s psychology. Professor Yang Gongxia from Tongji University has made a wonderful description in the fifth chapter of his book “Visual and Visual Environment.”

Under different light sources, the same object will show different colors. For example, the green leaves are bright green under green light, and nearly black under red light. Thus, the light source plays an important role in the appearance of the illuminated object. The ability of the light source to fully display the color of the object being illuminated is known as the color rendering of the light source.

In 1965, the International Commission on Illumination recommended using the general color rendering index Ra to describe the color rendering of a light source in the CIE colorimetric system. The general color rendering index Ra has been applied successfully, and it has been widely accepted by the lighting industry. However, there are also some problems. This article will give an introduction to the methods of evaluating the color rendering of light sources and the progress made in recent years.

The general color rendering index Ra

The evaluation method of the light source color rendering is hoped to be both simple and practical. However, simplicity and utility are often two conflicting requirements. In the CIE color system, the general color rendering index Ra is a product of such a trade-off: it is relatively simple, only requires a value within 100 to express the color rendering performance of the light source, and Ra=100 is considered as the optimal color rendering. Sex.

However, sometimes people do not feel that way. For example, leaves under incandescent lighting do not look too bright. Where is the problem? Let’s discuss what is the general color rendering index.

For the sake of simplicity, we will only discuss the main constitutional methods of the general color rendering index Ra without discussing its specific calculation method.

In fact, we often examine the color rendering of light sources in our daily lives. Many people have this experience. When an attentive lady buys clothes at a shopping mall, she often has to look outside to see its color. In doing so, she is actually testing the color rendering of the mall’s light source: look at the same piece of clothing, under the lighting of the mall light source and under the illumination of the sun, what is the color of the clothes. So to describe the color rendering of a light source, two additional elements are needed: daylight (reference light source) and clothes (colored objects).

In the CIE color system, in order to determine the color rendering property of the light source to be measured, a reference light source is first selected, and it is considered that under the irradiation of the reference light source, the color of the illuminated object can be displayed most perfectly. The CIE color system provides that: when the correlated color temperature of the light source to be measured is lower than 5000K, the blackbody with the closest color temperature is used as a reference light source; when the correlated color temperature of the light source to be measured is greater than 5000K, the D light source with the closest color temperature is used as a reference light source. The D light source here is a series of sunlight that can be digitally represented by color coordinates and related to the color temperature.

After the reference light source is selected, colored objects also need to be selected. Due to the diversity of colors, it is necessary to select a set of standard colors so that they can fully represent commonly used colors. The CIE color system has selected 8 colors, which have a variety of hues, as well as medium brightness values ​​and chromaticity.

In the u-v color system, each standard swatch is measured, and the special color rendering index Ri of the swatch can be obtained under the illumination of the light source to be measured and the difference in color coordinates under the illumination of the reference light source, that is, the color displacement ΔEi. (Ri=100-4.6ΔEi)

The average color rendering index Ra is obtained by arithmetically averaging the special color rendering index Ri measured for the eight standard swatches. The maximum value of the general color rendering index Ra of the visible light source is 100, and it is considered that the color rendering property of the light source is best at this time.

Limitations of the general color rendering index Ra

Although the general color rendering index Ra is simple and practical, it shows serious shortages in many aspects.

First of all, color is the subjective feeling of people. It is not an inherent property of an object. It is related to lighting conditions, observers, irradiance, illumination, surrounding objects, and observation angles. There is no so-called “real color”.

However, since in the CIE system, Ra is defined to have a maximum value of 100 under irradiation of approximately black body, the bulb manufacturer consciously designs the light bulb so that the color rendering property when irradiating the object with it is as close as possible to the black body or sunlight. This means that when the spectral distribution of the light source deviates from the black body or sunlight, the color rendering index decreases. For example, a white LED composed of three monochromatic LEDs of red, green, and blue, when its general color rendering index Ra is low, its color rendering property is not always very bad.

But in fact, researchers Judd, Thorntou, and Jerome have proven that people don’t necessarily like the color of the reference light source lighting specified by CIE. For example, it is not necessarily the best choice to illuminate green leaves with an incandescent lamp with a low color temperature. It is stipulated that the color rendering index is an optimum value of Ra=100 in black body or sunlight irradiation.

The reference light source specified by CIE is the black body or daylight that is the closest to the correlated color temperature of the light source to be measured. They are all light sources that emit continuous spectrum and have spectral components of various colors. When the color temperature is 6500K, the spectral power distribution of the long-short wave is relatively balanced, and it should be said as a reasonable reference light source. However, when the color temperature is below 4000K, the spectral power distribution is seriously asymmetric, and the blue short-wave spectral power is much smaller than the red long-wave spectral power. Its color is biased toward red, and there is doubt as a reference light source.

In the CIE color system, the eight standard swatches are at medium brightness and color saturation, and are equally spaced in u~v systems. For indoor lighting, they are considered to be able to adequately represent a variety of commonly used colors. However, in outdoor lighting, there are often colors with high color saturation, and these 8 standard color plates cannot fully represent commonly used colors.

Many scholars believe that the number of standard swatches is too small, which is another deficiency of the general color rendering index. Although the CIE still has 6 color plates with higher saturation levels 9-14, they are not included in the general color rendering index Ra. In lighting practice, people are familiar with the colors of the skin, leaves, food, etc., their color is extremely important, but they are excluded from the general color rendering index.

Seim had proposed using 20 standard swatches, but this was rejected because it would make the calculation too complicated. Currently, computers are widely used. It seems that this proposal has to be reconsidered.

Since there are two major problems in the evaluation of the color rendering of the light source and many other evaluation methods have caused widespread interest, this article will briefly introduce the author’s knowledge.

Fleury index Rf

Studies have shown that people tend to remember the colors of more familiar objects and remember their vivid, saturated colors. This memory color is often consistent with the favorite color, and tends to shift to the high saturation. For example, the memory color of people’s skin color tends to shift in the red direction and the color of the leaves shifts in the green direction. Obviously different from the Ra method in CIE.

Rf is actually a correction to Ra. This amendment includes two aspects:
First, Rf=90 is defined under the illumination of the reference light source, and only Rf=100 under the imaginary “perfect light source” illumination.
Second, choose 10 standard swatches, that is, in addition to the original 1-8 standard swatches, plus 13 swatches of 14th, corresponding to skin color and leaf color.

At this time, the “perfect light source” refers to the light source that can displace the colors of the 10 standard swatches toward the preferred direction under its illumination.

Thus, for each standard swatch, the color coordinates of the corresponding “perfect light source” are different and can be determined experimentally. This also shows that such a “perfect light source” can only be hypothetical.

Rf’s method for calculating bids is similar to Ra, but it differs in two ways:
1. For each standard swatch, the color coordinate of the reference light source needs to be adjusted, that is, the “perfect light source” color coordinate determined according to the experiment. Then, when the light source to be measured is illuminated, the color difference of each swatch is compared with its corresponding “perfect light source”.
2. When calculating Rf, take the average of the color difference of 10 swatches, but the weight of each swatch is different. The swatch number 13 is skin color, the weight is 35%, number 2 is 15%, number 14 is 15%, and the rest is 5% each. This emphasizes the importance of skin color. Therefore, the Rf of the light source to be measured may be higher than the reference light source Rf=90 but less than 100.

Color preference index (CPI)

The color preference index (CPI) uses the concept of love color proposed in the previous section. It is defined under the illumination of the D65 light source and the color preference index CPI =100.

So the CPI of the light source to be measured can be obtained by calculating the difference between the color coordinates of the 8 standard swatches and the color coordinates of the favorite color under the light source to be measured, and calculating the average of the vector sums ( ): CPI=156 -7.18()

The above calculations are performed in the CIE’s UV colorimetric system.

Although both CPI and Rf use the concept of favorite color, the two are quite different:
1. When calculating Rf, use 10 standard swatches for numbers 1 to 8 and 13 and 14, while CPI uses only 1 to 8 standard swatches
2. When the technique Rf, the color difference (ΔE) takes 1/5 of the experimental value, and the CPI takes the original experimental value
3. When calculating Rf, the weights of the swatches in each block are different, and the CPI takes the same weight.
4. According to the definition, the maximum value of Rf is 100, and the maximum value of CPI is 156.

Finally, it should be pointed out that researchers who proposed the two indexes of Rf and CPI both determined the favorite color experimentally, and used daylight color illumination in the experiment. There is now evidence that the love color relates to the correlated color temperature of the light source. Therefore, when using Rf and CPI for constant color rendering, only high color temperature light sources are used.

Color separation index (CDI)

Use Ra, Rf or CPI to describe the color rendering of the light source. The reference light source must have the same color temperature as the light source to be measured. The color discrimination index (CDI) overcomes this limitation.

The index proposes an assumption based on the assumption that under the illumination of a certain light source, the stronger the ability to distinguish colors, the better the color rendering of the light source. When lighting a certain light source, the area of ​​the eight standard swatches in the CIE UV chromaticity diagram is: GA = 0.5Σ(UiVj-UjVi) i,j=1,2,…8; i≠j .

Under C light source illumination, this area GA = 0.005, define CDI = 100 at this moment, so under the illumination of the light source to be measured, its chroma exponent index is: CDI = (GA/0.005) * 100.


From the above discussion, we can see that there are many ways to evaluate the color rendering of light sources, and in the course of continuous development and improvement, this article is only a part of them. Each has its own advantages and disadvantages. Even the widely used general color rendering index Ra has many disadvantages.

Its main drawback is the choice of the reference light source: The reference light source is a spectrally continuous light source, and it is not very suitable to use it as a standard to measure light sources with discontinuous spectra. The color temperature of the reference light source must be similar to the correlated color temperature of the light source to be measured, and in fact, for a certain lighting operation, the color temperature itself has a great influence on the color rendering. This method limits the color temperature of the light source that can only be used. Use under conditions.

Its second drawback is the choice of standard swatches: For indoor lighting, it can be assumed that 8 standard swatches can adequately represent a variety of commonly used colors. However, in outdoor lighting, colors with high color saturation do not fully represent commonly used colors.





Lens and reflectors

Secret Reflector and Lens

Lens and reflectors

What is a reflector and what is a lens? This problem has puzzled me a long time ago. I believe many people, like I used to, think that the reflector and the lens are actually very similar, but they are not the same in structure, and they are still the same when using.So there are not many people to go deep into this issue.

As we all know, reflectors and lenses belong to the secondary optics, the role of secondary light distribution of light, they can be said to be the core of the efficacy of lighting, if there is no such core application, then the lighting market is about to return to the original The stage is full of fluorescent tubes. Since it is said to use, let us first understand the difference between the reflector and the lens.

The effect of the lens is relatively perfect, generally there is no sub-light spot, the light shape is relatively beautiful; and the effect of the reflector cup comes with the secondary light spot, and the light shape has a layered effect. I believe that a friend with a normal aesthetic view will feel that the effect of the above chart is more suitable for displaying the artistry of the paintings. However, having a sub-spot is a bit unsatisfying, and it can even be said to be awkward, but this means that the reflector with sub-bright spots has no Use it? That’s not.

For a scene, it is still a reflector, still a secondary spot, but when the secondary spot effect is fully highlighted, in fact, its aesthetics is not a grade to speak of before, so in the end is the choice of lens or Reflector cup as a secondary light distribution element this problem, almost with the so-called boyfriend asked her girlfriend and his girlfriend out of the water, in the end to save the eternity of the problem.

This is also a problem that puts the cart before the horse. First of all, for developers, you need to figure out where your needs are, where they are used, and what kind of lighting effects they need to achieve. Then it is the further implementation process and the implementation of the plan.

Or the phrase that can achieve the effect is what you need is also the optical component that you feel is the best. They are not good or bad.

The next step is to recommend suitable lighting fixtures and lenses for everyone (in the absence of optical requirements).


1. Downlights (wall lights)

Lamps like downlights are generally installed on the walls of corridors. They are also one of the lamps that are closest to the eyes of people. If the light of the lamps is relatively strong, it is easy for people to show psychological and physiological incompatibility. Class design, in the absence of special requirements, the general use of the reflector effect will be better relative to the lens, after all, there is an excess of secondary spots, will not let people walk in the corridor will feel because a certain point of light is too powerful, leading to Uncomfortable eyes.

2,LED flood light (spot light)

Floodlights are generally based on lighting a certain thing, it requires a certain range and light intensity, more importantly, it needs to clearly show the physical exposure in the human field of vision, so this kind of lighting, Also far from people’s eyes, generally do not produce uncomfortable lamps, when designing, the use of lenses will be better than reflective cups. If it is done in the case of a single light source, the effect of pinching the Phil lens is better, after all, The range is not comparable to ordinary optics.

3, wall washer

Wall washers are generally used to illuminate walls. They have many internal light sources. If reflectors with strong secondary spots are used, they can easily cause people to adapt to them. Therefore, they are similar to those used for wall washers. The lens is better than the reflector.

4, LED High Bay Light

This is really a product that is difficult to choose. First of all, it is important to understand the locations of factories, highway toll stations, large shopping malls and other large-scale areas where there are many applications, such as height, Width is very easy to interfere with the application of the lamp, then the mining lamp how to choose a lens or reflector it?

In fact, the best way is to determine the height of the installation, compared to the end of the distance from the person’s eyes closer to the site, the use of reflectors recommended, the installation of a relatively high height, it is recommended to use the lens. There is no reason for it, and because of the distance from the eye too close, it requires an excessive, high distance from the eye and requires a range.