Exploring LED filament lamps: a gust of hot air or a revolution in light sources?

Technological breakthrough - 360-degree full-angle luminous stereoscopic light source

　　The emergence of tungsten filament incandescent lamps in the 19th century led the world into the era of artificial lighting . Since the emergence of the revolutionary new light source LED in the 20th century, it has quickly become popular in the lighting market with its advantages of energy saving, environmental protection, and long life. LED has become the mainstream lighting source in the future and is widely used in commercial lighting, industrial lighting, outdoor lighting, etc. However, the development of civil lighting is relatively slow. For many people, LED lights are a new light source that they have never heard of. In 2008, Japan's Ushio Light Source launched the "LED filament bulb" with an incandescent lamp prototype and LED bulb-type lamps, which reversed this phenomenon. "Traditional appearance, upgraded 'formula'", people can see that it is a familiar lighting fixture when they see the LED lamp made of it. Subsequently, candle lamps, crystal lamps, and bulb lamps with LED filaments as light sources began to appear in large numbers and were accepted by more and more consumers.

　　Ordinary LED lamp beads are single chips with a voltage of 3.0V fixed in a plastic bracket cup, and then packaged with glue, that is, PLCC packaging. The LED filament process usually involves packaging 28 0.02W 1016 LED chips in series on a glass substrate with a length of 38mm and a diameter of 1.5mm, and then applying mold-top fluorescent glue. The LED filament is driven by a 10mA current, a voltage of 84V, a power of 0.84W, a luminous flux of 100lm, and a luminous efficiency of 120lm/W. If paired with a red chip, the color rendering index can reach more than 95. In addition, the low current and high voltage characteristics of LED filaments effectively reduce the heat generation of LEDs and the cost of drivers, and have outstanding advantages.

　　LED filaments can be used to make various small and medium power LED bulbs or candle lights. Usually, four LED filaments are used, two in series and two in parallel to design a 3.6W LED bulb or candle light with a luminous flux of 400lm, which can replace a 40W incandescent bulb.

　　Compared with incandescent lamps and ordinary LED lamps, LED filament lamps have both advantages and avoid their shortcomings:

　　1. 360-degree full-angle luminous stereo light source

　　Previous LED light sources, such as plug-in LEDs, SMD LEDs, COBs, integrated high-power LED lamp beads, can only be planar light sources without optical devices such as lenses. However, LED filaments have broken through this point and use microporous metal substrate single-sided solid crystal welding wire technology to truly achieve a 360-degree full-angle luminous stereoscopic light source, avoiding the problem of light effects being affected and light loss caused by adding lenses, meeting customers' full-angle luminous needs, bringing unprecedented lighting experience and more energy saving.

　　2. High color rendering index and high light efficiency

　　The blue light + red light chip package can make the color rendering reach the effect of traditional lighting, improve the light efficiency and brightness, and replace the traditional process of adding blue light and red and green phosphors to increase the color rendering index at the expense of brightness.

　　3. Conform to people's habits of light source appearance

　　LED filaments meet consumer demand: When incandescent lamps and energy-saving lamps still dominated the market, the products most accepted by ordinary consumers were lighting fixtures that did not change their previous habits. LED filaments fully meet consumers' habitual understanding of lighting fixtures.

　　4. Compared with ordinary LED lights, the cost is lower

　　Compared with general LED lamps, LED filament lamps mainly use sapphire substrates and wicks instead of non-renewable aluminum and non-degradable plastics. Since the phosphor is only coated on a 0.8mm sapphire substrate, the amount of phosphor used is less than that of ordinary packaging. From the current mainstream models, according to the power, only 25, 28, and 32 chips are generally used for packaging. Compared with ordinary packages of the same wattage, the amount of LED chips used is also less, so the overall cost is correspondingly lower than that of ordinary LED lamps.

　　Domestic enterprises are competing for the LED filament lamp market

　　Zhongzhou Optoelectronics has fully deployed the production of LED filament lamps. Zhongzhou Optoelectronics stopped its original LED packaging business in June 2013 and focused on the research and development and production of LED filaments. "Currently, Zhongzhou Optoelectronics' monthly production capacity of LED filaments has reached 6 million pieces, and it is produced according to orders." Yu Xiang, sales director of Zhongzhou Optoelectronics, revealed that Zhongzhou Optoelectronics currently focuses on the sales of LED filaments and has begun to deploy the production of LED filament lamps.

　　Recently, Zhejiang Shendu Optoelectronics Technology Co., Ltd. announced that it will fully develop and manufacture LED filament bulbs. The production base located in Xianju County, Zhejiang Province is mainly used to produce LED filament bulbs, and plans to become a leading domestic LED filament bulb manufacturer within two years. Regarding the production target, the company said: "Our feature is mass production of a small number of varieties. This is the only way to play the scale advantage in the subdivided field."

　　Yapul successfully transformed through LED filament lamps. In recent years, Yapul, a traditional incandescent lamp manufacturer, has tried to find a way to successfully transform to LED. At the end of 2011, it began to try to invest in the research and development of LED filament lamps, and successfully launched them in June 2012. In March 2013, Yapul optimized its products and established the first production line in Guanghan, Sichuan. In February 2014, it established a second production base in Shanghai. Today, Yapul's filament lamp production capacity has reached 4 million units per month, and this year's goal is 10 million units per month. At present, Yapul has established LED lighting as its main direction for the next three years, and plans to go public in 2017. "With LED filament lamps, LED light sheets, and T5 and T8 lamp tube auxiliary belts as the main business direction, we will achieve a sales target of 1 billion yuan in 2014."

　　From the successful transformation of Yapul, we can see that the emergence of LED filament lamps is undoubtedly a blessing for incandescent lamp companies that are in a difficult situation of "energy conservation and emission reduction". Companies can use existing technology and assembly lines to produce LED filament bulbs, use the original glass bracket of incandescent lamps to design the connection of LED filaments, and use the special glass with high light transmittance of incandescent lamps and automatic glass blowing bulb production technology to produce bulbs in the shape of incandescent lamps, thereby producing LED filament bulbs with good cost performance. This is also the breakthrough for incandescent lamp companies to transform to LED.

　　Current technology development status and technical bottlenecks

　　At the Frankfurt Lighting Fair in Germany and the Hong Kong Lighting Fair in Spring, LED filament lamps were not uncommon. It is understood that LED filament lamps have long been popular in foreign markets, mainly in North America, Europe, and South America. However, in China, only in the past two years have companies vigorously promoted LED filament lamps. What is the reason?

　　In this regard, Shenzhen Delipu Product Manager Pu Cheng analyzed that, first, in the context of the price war of LED light sources, some packaging companies hope to gain market position and profits through differentiated products, and hope to cooperate with downstream manufacturers to concentrate their advantages to promote new products, but they cannot snatch the market share of existing bulb customers, so many companies have chosen to develop LED filament lamp products; second, LED light source products have expanded from the initial pursuit of light efficiency to light quality, and companies are more concerned about light experience, and LED filament lamps have this advantage; third, domestic packaging technology has only developed to this stage with the ability to mass-produce.

　　At present, the cost price of LED filament lamp beads is still relatively expensive, which is reflected in several aspects: material cost, labor cost, efficiency, yield rate, and R&D cost. Regarding the cost, Yapul said frankly, "If the yield rate of the current filament lamp is not taken into account, and only the material and labor costs are calculated, the cost is currently at the 3 yuan stage, specifically 3 yuan per filament, 3 yuan for the power supply (constant current source), and 3 yuan for the glass bulb, packaging, labor, gas, etc." Whether calculated by W/$ or LM/$, the current price of LED filament lamps in China is not obviously superior to ordinary LED light source products, and it is determined by the size of the order quantity. "It will gradually enter the 1.5 yuan stage in the future, and it is estimated that it will enter the 1 yuan or less stage at the end of 2014 and the beginning of 2015." Yapul said confidently.

　　As an emerging technology, it is normal for LED filament lamps to encounter bottlenecks during the research and development process. Due to the different nature of the enterprises and their investment in research and development, each enterprise encounters different difficulties. Mr. Tang from the packaging company Shenzhen Yuanlei said that the difficulties currently encountered are from equipment, inconsistent specifications, process efficiency, product performance, etc. The equipment needs to be modified according to the performance characteristics of the filament, but there is no such modification on the market for the time being. Mr. Zhang from Zhejiang Shendu, a traditional lighting manufacturer that has transformed into LED filament lamps, said, "The key at present is to increase the power. The company is already working on 4W, 6W, and 8W, and is developing 10W and 12W products with a luminous flux of 120LM per W. The design of heat dissipation is also a focus of research."

　　LED filament lamp is just a gust of hot air?

　　"LED filament lamps are just transitional products from incandescent lamps to LED lighting, and are just a passing fad," there is a popular saying in the industry. In response to this statement, the reporter interviewed some companies:

　　Zhang Zhen, general manager of Zhejiang Shendu, said that LED filament lamps are the lighting of the future. The 50,000-hour lifespan of ordinary LED light sources on the market is unfounded. Even if a product is always on after 10 years of use, it still needs to be replaced. Therefore, what the market really needs is a product with high cost performance. No other LED lamp can compare with the cost performance of LED filament lamps. In the future, the price of this product will be less than 10 yuan. "From a market perspective, LED filament bulbs reduce the overall cost of LED lamps on the one hand, thereby enhancing the competitive advantage of LED lamps over traditional lamps, which is conducive to LED lighting entering ordinary households; on the other hand, its appearance greatly facilitates our new product development. More importantly, LED filament bulbs fully meet consumers' habitual understanding of lighting lamps. A large number of talents are developing filament lamps, which will definitely drive the development of LED lamps. Filament lamps will inevitably be active in the lighting market due to their unique performance and price."

　　Pu Cheng, product manager of Shenzhen Delipu, said that LED filament lamps are transitional products, but it depends on how long this period will last. LED filament lamps are used as artistic light sources in home decoration and commercial lighting, and the lighting effect is the original intention of customers to buy them. The current LED fluorescent lamps and LED downlights are developed based on the traditional lighting structure and usage requirements. In this way, they are also transitional products.

　　Sun Ming, deputy general manager of Shanghai Yapul, said, "We believe it is the ultimate product of LED bulbs, a perfect combination of LED and traditional light sources. This product realizes full-axis light in the true sense, has ultra-high light efficiency, perfect CRI, scientific appearance design, truly achieves energy saving and environmental protection, and is a perfect match with traditional lamps! Its application prospects will be very broad!"

　　"Starting from 2014, the "ban on white" policy in countries and regions such as the United States, China, South Korea and Australia will be extended from the existing commercial and industrial fields to the civilian field, and energy conservation and emission reduction will be implemented in residential indoor lighting. The development of LED filament lamps is timely. The development of LED filament lamps may not be just a hot trend. Its emergence has a revolutionary significance. As long as the technical bottleneck is broken through and the cost price is reduced, the impact on the LED lighting field will gradually increase in the future. Moreover, it meets the needs of a part of the "nostalgic" crowd. The market potential of this part is very considerable and will occupy a part of the market in the future."