Comprehensive review of the application of LED lamps and electrodeless lamps

High-frequency electrodeless lamp is a light source based on the combination of two well-known principles: gas discharge of fluorescent lamp and high-frequency electromagnetic induction. Since there is no filament or electrode in the bulb, there is no necessary component to limit the life of the light source. The general theoretical life can reach more than tens of thousands of hours. It is mainly composed of three parts: high-frequency generator, power coupler and glass bulb.

The principle of its luminescence is: after inputting a certain range of power supply voltage, the high-frequency generator generates a 2.65MHZ high-frequency constant voltage and sends it to the power coupler. The power coupler establishes a strong electrostatic magnetic field in the discharge space inside the glass shell, ionizes the atmosphere in the discharge space, and produces strong ultraviolet light. The three-primary color phosphors on the inner wall of the glass bulb are stimulated by the strong ultraviolet light to emit light.

LED is a semiconductor light emitting diode.

The heart of LED is a semiconductor chip. One end of the chip is attached to a bracket, one end is the negative pole, and the other end is connected to the positive pole of the power supply, so that the whole chip is encapsulated by epoxy resin. The semiconductor chip consists of two parts, one part is a P-type semiconductor, in which holes dominate, and the other end is an N-type semiconductor, which is mainly electrons. But when these two semiconductors are connected, a "PN junction" is formed between them. When the current acts on the chip through the wire, the electrons will be pushed to the P area, where the electrons and holes recombine, and then they will emit energy in the form of photons. This is the principle of LED light emission. The wavelength of light determines the color of the light, which is determined by the material that forms the PN junction.

LED lamps are high-brightness white light-emitting diodes with high light efficiency, low power consumption, long life, easy control, maintenance-free, safe and environmentally friendly. They are a new generation of solid cold light sources with soft, bright, colorful light, low loss, low energy consumption, and green environmental protection. They are suitable for long-term lighting in roads, homes, shopping malls, banks, hospitals, hotels, restaurants and other public places. Flicker-free direct current has a good protective effect on the eyes and is the best choice for table lamps and street lamps.

In order to better understand LED lamps and electrodeless lamps, we can use the following table to get a relatively intuitive understanding of the performance of these two types of products.

Table 1 Basic comparative analysis of induction lamps and LEDs

Compare Projects	Induction lamp	LED Light
Technology name and features	Low Voltage Discharge Low Voltage Discharge Induction Luminescence Surface light source, suitable for high-power functional lighting	Lighting Emit Diode solid light emitting diode Point light source, flexible application, suitable for various lighting
Technological advancement	Domestic research and development began in 2000 and sales began in 2004. At the advanced stage of light source development, standardized products cannot meet market needs, so this high-tech product has not yet been mass-produced.	The first red LED was successfully developed in 1968, and it has been developed for nearly 40 years. The first white LED was successfully developed in 1996. The technology has been steadily improved and gradually matured, and it is suitable for various functional lighting occasions. Its overall development speed is relatively fast. It has been favored by lighting companies around the world;
Market Capacity	As a new type of functional lighting source, induction lamps can replace some traditional functional lighting sources. The market capacity is relatively small.	LED has been developed for decades. It has high luminous efficiency, arbitrary power combination, and relatively many supporting lamps. It can be used for display lighting, traffic lights, car taillights, road lighting, various indoor lighting, etc.
Economical	As induction lamps are mass-produced, their prices will be on par with those of traditional light sources.	The cost is relatively high, but due to its various advantages of energy saving and environmental protection, it can adapt to the wide market demand and is widely used in the market. It is the best choice to replace traditional light sources.
Energy saving rate	The lighting effect of electrodeless lamp is more than 20% lower than that of LED lamp, and the light decay is greater than that of LED, so the energy saving rate is about 40% lower than that of LED.	LED has high light efficiency, low power, low light decay, and better energy saving effect than electrodeless lamp. (Reasonable design and production is the prerequisite)
Applications	Industrial, road, tunnel, bridge, advertising and other lighting fields	The scope is broad, including special lighting fields such as traffic signals, car taillights, display screens, as well as indoor and outdoor lighting fields such as industry, commerce, roads, tunnels, bridges, gardens, agriculture, and advertising.
Practical Application	Since many technical problems need to be solved and overcome, it is difficult for electrodeless lamps to be truly applied to a wide range of functional lighting occasions, and industrialization and large-scale production are difficult to achieve. Application stability and electrical problems have not yet been solved;	LED lights have been widely used in many lighting projects, with broad prospects for actual promotion and application, fast industrialization and significant scale effect. Especially in the field of LED road lighting, it has been promoted as a demonstration project by the National Development and Reform Commission;
Technical indicators	1. Power: 15W~200W 2. Luminous efficiency: 80 lm/W 3. Color rendering index: 80 Ra 4. Color temperature: 2100K~6500K full range 5. Color temperature difference: +/_300K 6. Light decay: 5%@2000 hours 7. Service life: <8,000 hours (currently actual) 8. Heat generation: The lamp tube is high and the phosphor ages quickly; 9. Lamp matching: Lamp matching is relatively difficult; 10. Surface light source: Fluorescent source, low lamp efficiency, difficult light distribution, and low light flux utilization of the light source;	1. Power: Diverse options are available based on actual application. 2. Luminous efficiency: >130 lm/W (white light) 3. Color rendering index: >80 Ra 4. Color temperature: The selection range is adjustable based on requirements; 5. Color temperature difference: +/_200K 6. Light decay: >2%@2000 hours 7. Service life: >50,000 hours 8. Heat generation: High, which can be completely solved through thermal technology. 9. Lighting accessories: Professional, integrated lighting accessories; 10. Point light source: Easy to match light, high light flux utilization rate, more energy-saving and efficient.

Table 2 Application technical parameters and detailed comparison of induction lamps and LED lamps

Parameter comparison table:
Project Name	Induction lamp	led
Light source category	Gas discharge	Solid state light
Lighting effect	65~78Lm/W	>80Lm/W or above
Light decay	Faster	Small
life	<8000 hours (actual application)	>50000 hours
Operating frequency	2.65MHz	50Hz
Startup Features	Delayed start	Start now
Light Directivity	Difference	powerful
Shock resistance	Difference	Very strong
Installation	Complex (lights need to be installed in a predetermined orientation)	Simple (the lamp can be installed in any direction)
Thermal treatment	need	need
Glare	Large (has strong glare)	Small (application glare less than <15%)
EMC electromagnetic radiation interference	Seriously exceeded*	Meet national standards
Light color temperature	Optional	Optional
spectrum	Width	Colorful
Single power	40～200W	0.05～10W
UV component	Contains UV	UV-free
Green and Environmentally Friendly	No (contains mercury)	Yes (contains no mercury)
maintain	need	waived
Security	weak	powerful
Application Areas	Factories, non-main road lighting and other fields	Landscape lighting, road signs, car lights, etc. Outdoor, street lights, factories, mines, tunnels, supermarkets and other indoor and outdoor lighting fields
Extended Application	Traditional low-power lighting field	Replace traditional light sources

*In 2008, there was an incident in Shenzhen where the use of electrodeless lamps interfered with the operation of the airport navigation system. / "Analysis of the serious interference of high-frequency electrodeless lamps on aviation dispatch frequency"
Data link: http://www.mni.cn/Mni_docu54.html

Table 3 Energy saving comparison between 150W induction lamp and 100W LED replacing 250W sodium lamp under the same lighting conditions

project	sodium lamp	Induction lamp	LED Street Lights	LED street lights save more energy than electrodeless lamps	Remark
Light source power W	250	150	100	33%
Total line loss (6%) W	18	7.5	5	33%	International standard 5%
Transformer loss (3%) W	9	4.5	3	33%	100KVA transformer minimum level 3%
Total power	277	162	108	33%
Power Factor	0.8	0.85	0.95
Actual power consumption	346.25	190.59	112.5	41%
Uniformity	0.3	0.50	0.7
Appliance efficiency	60%	75%	More than 90%
Intelligent Control	none	none	Can intelligently control power output
Daily power consumption of a single lamp (kWh)	4.155	2.287	1.35	41%	Based on 12 hours per day, LED street lights can be intelligently controlled, with 6 hours of full brightness and 6 hours of half brightness, and the power is halved.
Annual power consumption of a single lamp (kWh)	1516.575	834.776	492.75	41%
Annual electricity saving per lamp (kWh)	0	681.798	102.382	342.026	Under the same conditions, LED energy saving effect is more obvious;

Table 4 Energy saving comparison between 250W induction lamp and 160W LED replacing 400W sodium lamp under the same lighting conditions

project	sodium lamp	Induction lamp	LED Street Lights	LED street lights save more energy than electrodeless lamps	Remark
Light source power W	400	250	160	36%
Total line loss (6%) W	20	12.5	8	36%	International standard 5%
Electrical consumption (3%) W	12	7.5	4.8	36%	100KVA transformer minimum level 3%
Total power	432	270	172.8	36%
Power Factor	0.8	0.85	0.96
Actual power consumption	540	317.65	180	43%
Uniformity	0.3	0.50	0.7
Appliance efficiency	60%	0.70	More than 90%
Intelligent Control	none	none	Can intelligently control power output
Daily power consumption of a single lamp (kWh)	6.480	3.81176	2.160	43%	Based on 12 hours per day, LED street lights can be intelligently controlled, with 6 hours of full brightness and 6 hours of half brightness, and the power is halved.
Annual power consumption of a single lamp (kWh)	2365.2	1391.294	788.4	43%
Annual electricity saving per lamp	0	973.905	1576.8	602.894	Under the same conditions, LED saves 602 kWh more electricity than electrodeless lamp;

It has been more than 100 years since the invention of the "electrodeless lamp", and the road it has traveled has been difficult and tortuous. It has also been more than ten years since my country began to develop and produce "electrodeless lamps".

Since Edison invented the light bulb, the life of lamps has been greatly improved, from filaments to filament-free lamps. However, the short life of filaments and electrodes is the main reason affecting the life of lamps. Therefore, people naturally think of ideal lamps without filaments or electrodes.

The light sources we are currently exposed to mainly include the "thermal light source" of incandescent lamps, the "ultraviolet excitation light source" of fluorescent lamps/energy-saving lamps, the "arc light source of high-intensity discharge lamps", and the "semiconductor LED light source" that is currently very "hyped".

We know that when fluorescent powder is exposed to "ultraviolet light" or "microwave", it will be stimulated to emit white light. The arc in the tube of energy-saving lamp generates "ultraviolet light" to illuminate the fluorescent tube. And "electrodeless lamp" uses "microwave generator" to stimulate fluorescent powder to emit light.

Therefore, since the "electrodeless lamp" has no electrodes, theoretically, its life span can reach 60,000 hours. This is the biggest advantage of the "electrodeless lamp", but we currently believe that this is also the only advantage of the "electrodeless lamp". However, even this advantage is questionable.

1. Lifespan of “electrodeless lamp”:

The theoretical life of an induction lamp is 60,000 hours, but in reality, there has been no fundamental breakthrough in the technology of high-power electronic ballasts. At the same time, the life of components, including "electrolytic capacitors", is only 16,000 hours in the high-temperature environment of an induction lamp. Under current technical conditions, the actual life of an induction lamp is less than 8,000 hours, so the theoretical life cannot be used for publicity.

In the Ministry of Construction's "Implementation Rules for the 11th Five-Year Plan for Urban Green Lighting Projects", Article 18 states that electrodeless fluorescent lamps should have an effective life of ≥ 60,000 hours, and the light flux maintenance rate of the light source should not be less than 70% during the effective life. It can be seen that it is too early for electrodeless lamps to meet the requirements of the Ministry of Construction and enter the lighting market.

2. Lighting effect of "electrodeless lamp":

Theoretical luminous efficiency of induction lamp is only 80Lm/W, while the actual luminous efficiency of some products is only 65Lm/W, which is comparable to energy-saving lamps, and cannot be compared with the current street lamps, "sodium lamps/metal halide lamps" (sodium lamps/metal halide lamps have luminous efficiency of 110Lm/W--120Lm/W), let alone LED lamps (LED lamps have luminous efficiency of more than 120lm/W). When manufacturers promote energy saving, they compare it with the luminous efficiency of "incandescent lamps".

Because the efficiency of induction lamps is low, compared with sodium lamps, the same light consumption means more power consumption and more heat. If you use 185W induction lamps to replace 250W sodium lamps, it will only be darker, which is an indisputable fact.

The current electrodeless lighting effect does not comply with the national energy-saving industry policy.

3. Light decay problem of "electrodeless lamp":

The theoretical service life of high-frequency electromagnetic electrodeless lamps is 60,000 hours, and their lumen maintenance rate can be maintained at more than 70%. However, the light decay of low-frequency electromagnetic electrodeless lamps is difficult to control, and some of them have lost more than 50% of their lumen after less than 1,000 hours of use.

4. The cost of "electrodeless lamp":

Since the actual life of electrodeless lamps is difficult to reach their theoretical life, and the cost of "electronic ballasts" is high, once a 185W electrodeless lamp is damaged, the cost of replacing all the lamps is as high as 500 yuan or more per lamp. However, if a sodium lamp is damaged, you only need to replace a lamp tube at 40-60 yuan.

5. Problems of electromagnetic interference and space electromagnetic radiation from "electrodeless lamps":

The electrodeless lamp works on "electromagnetic waves or microwaves". Its microwave generator emits ultra-high power electromagnetic waves, which can propagate up to a thousand kilometers. It is an "interference source" that cannot be solved at close distances. A large amount of information and manufacturers say that electromagnetic interference was solved as early as 2004. However, in 2008, a serious accident of "electrodeless lamp interfering with aviation navigation system" occurred at Shenzhen Airport in my country.

In the Ministry of Construction's "Implementation Rules for the 11th Five-Year Plan for Urban Green Lighting Projects," Article 25 states that electrodeless fluorescent lamps must pass electromagnetic interference tests because they operate at high frequencies, otherwise they will interfere with the power grid and nearby electrical appliances. Since electrodeless lamps rely on ultra-high-power "microwaves" to excite fluorescent powder to emit light, the "electromagnetic interference problem" cannot be solved at present.

The current electromagnetic compatibility technology of electrodeless lamps cannot meet the requirements of the Ministry of Construction.

6. Power factor and harmonic issues of "electrodeless lamp":

Manufacturers of "electrodeless lamps" all advertise that their power factor is as high as 0.98 or higher. We all know that power factor is a concept related to inductive or capacitive loads. Since full-bridge rectification is used and electrodeless lamps are non-inductive and non-capacitive loads, any circuit can easily achieve this indicator.

An important technical indicator of the electrodeless lamp is the "current harmonic" problem. If the APFC circuit is used, the problem can be solved, but the number of components will increase and the life reliability of the electrodeless lamp will be greatly reduced.

7. High power and heat dissipation issues of "electrodeless lamp":

There has been no breakthrough in the high-power electrodeless lamp, which is also related to its low light efficiency. We know that the heat generated by a high-light-efficiency sodium lamp at 170W makes the temperature of the quartz tube as high as 400℃, and the quartz tube can work for a long time at more than 700℃.

However, since the luminous efficiency of the electrodeless lamp is low, in order to emit the light of a 170W sodium lamp, it must consume more electricity and generate more heat. This heat must be dissipated in time, otherwise the magnet in the "electrodeless lamp" will reach the "Curie temperature" and lose its magnetism, and the magnetron will not work.

At present, the power of electrodeless lamps can generally reach 185W, while the power of traditional sodium lamps can reach 10,000W. Therefore, there is still a lot of work to be done to achieve high-power electrodeless lamps.

8. Standardization issues of "electrodeless lamps":

Since the induction lamp is still in the free trial and testing stage of street lamps, there is still a certain distance from market acceptance. At present, each company cites its own standards, and there is no national unified standard. Traditional lamps cannot be used for "induction lamps", the interface compatibility is poor, and the ballast is difficult to replace. If these problems are not solved, product maintenance will be very difficult. The glare of induction lamps is much heavier than that of metal halide lamps, which also makes it difficult for induction lamps to become the mainstream light source.

9. Misleading energy conservation by “electrodeless lamps”:

The only advantage of induction lamps is their long “theoretical lifespan”. It is unreasonable to say that induction lamps are energy-saving.

The current luminous efficiency of induction lamps is only 65-80Lm/W. To emit the same light, it must consume more energy than sodium lamps! Some dealers say: using 185W induction lamps to replace 250W sodium lamps means a significant decrease in brightness.

Compared with the above disadvantages of induction lamps, LED lamps have the following advantages:

LED is a semiconductor light emitting diode. LED energy-saving lamps use high-brightness white light emitting diodes as light sources. They have high light efficiency, low power consumption, long life, easy control, maintenance-free, safe and environmentally friendly. They are a new generation of solid cold light sources with soft, bright, colorful, low loss, low energy consumption, and green environmental protection. They are suitable for long-term lighting in homes, shopping malls, banks, hospitals, hotels, restaurants and other public places. Flicker-free direct current has a good protective effect on the eyes and is the best choice for table lamps and flashlights.

(1) High efficiency and energy saving: only a few kilowatt-hours of electricity are consumed in one thousand hours (an ordinary 60W incandescent lamp consumes 1 kilowatt-hour of electricity in seventeen hours, and an ordinary 10W energy-saving lamp consumes 1 kilowatt-hour of electricity in one hundred hours)

(2) Ultra-long life: The semiconductor chip emits light, has no filament, no glass bulb, is not afraid of vibration, is not easy to break, and has a service life of 50,000 to 100,000 hours (the service life of ordinary incandescent lamps is only 1,000 hours, and the service life of ordinary energy-saving lamps is only 8,000 hours).

(3) Health: Healthy light does not contain ultraviolet rays and infrared rays, and does not produce radiation (ordinary light contains ultraviolet rays and infrared rays)

(4) Green and environmentally friendly: It does not contain harmful elements such as mercury and xenon, is easy to recycle and does not generate electromagnetic interference (ordinary lamps contain elements such as mercury and lead, and the electronic ballast in energy-saving lamps will generate electromagnetic interference)

(5) Protect eyesight: DC drive, no flicker (ordinary lamps are AC driven, which will inevitably produce flicker)

(6) High light efficiency: low heat generation, 90% of the electrical energy is converted into visible light (80% of the electrical energy of ordinary incandescent lamps is converted into heat energy, and only 20% is converted into light energy) High safety factor: the required voltage and current are small, the heat generation is small, there is no safety hazard, and it can be used in dangerous places such as mines;

(7) The circuit board and the lamp cup of this lamp fit perfectly, without adhesive glue, and will never fall off. There is no need to worry about the lamp falling on the ground and breaking (unlike ordinary energy-saving lamps with glass lamp tubes). Compared with glass lamp cups, it is easy to dissipate heat (there are heat dissipation holes on the back), not easy to break, and has the same lighting effect as glass lamp cups. In addition, because the components can dissipate heat, they are not easy to age, and the overall service life is longer than that of glass lamp cups.

(8) Large market potential: low voltage, DC power supply, battery, solar power supply, and places with power shortage or low power supply such as remote mountainous areas and outdoor lighting.

The future of "induction lamp" and "LED lamp":

Both "electrodeless lamps" and "LED lamps" are competing for the position of the fourth-generation light source. Compared with the two, LED lamps are already clearly ahead of electrodeless lamps in terms of popularity and government attention. If electrodeless lamp manufacturers do not quickly repair and improve the above-mentioned shortcomings, it will only be empty talk for electrodeless lamps to truly become an ideal light source of "high efficiency and longevity". LED lamps are developing steadily along their inherent trajectory, the technology is becoming more and more mature, and the cost price is gradually decreasing with the maturity of technology. I believe that in the near future, LED lamps will be familiar and accepted by the general public, and become the ideal "high efficiency, longevity, energy saving, green and environmentally friendly" light source in people's minds.