nitrogen application for lcd displays made in china

This website is using a security service to protect itself from online attacks. The action you just performed triggered the security solution. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data.

This website is using a security service to protect itself from online attacks. The action you just performed triggered the security solution. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data.

Since its initial communalization in the 1990s, active matrix thin-film-transistor (TFT) displays have become an essential and indispensable part of modern living. They are much more than just televisions and smartphones; they are the primary communication and information portals for our day-to- day life: watches (wearables), appliances, advertising, signage, automobiles and more.

However, there are technology drivers and manufacturing challenges that differentiate the two. For semiconductor device manufacturing, there are technology limitations in making the device increasingly smaller. For display manufacturing, the challenge is primarily maintaining the uniformity of glass as consumers drive the demand for larger and thinner displays.

While semiconductor wafer size has maxed because of the challenges of making smaller features uniformly across the surface of the wafer, the size of the display mother glass has grown from 0.1m x 0.1m with 1.1mm thickness to 3m x 3m with 0.5mm thickness over the past 20 years due to consumer demands for larger, lighter, and more cost-effective devices.

As the display mother glass area gets bigger and bigger,so does the equipment used in the display manufacturing process and the volume of gases required. In addition, the consumer’s desire for a better viewing experience such as more vivid color, higher resolution, and lower power consumption has also driven display manufacturers to develop and commercialize active matrix organic light emitting displays (AMOLED).

In general, there are two types of displays in the market today: active matrix liquid crystal display (AMLCD) and AMOLED. In its simplicity, the fundamental components required to make up the display are the same for AMLCD and AMOLED. There are four layers of a display device (FIGURE 1): a light source, switches that are the thin-film-transistor and where the gases are mainly used, a shutter to control the color selection, and the RGB (red, green, blue) color filter.

The thin-film-transistors used for display are 2D transitional transistors, which are similar to bulk CMOS before FinFET. For the active matrix display, there is one transistor for each pixel to drive the individual RGB within the pixel. As the resolution of the display grows, the transistor size also reduces, but not to the sub-micron scale of semiconductor devices. For the 325 PPI density, the transistor size is approximately 0.0001 mm2 and for the 4K TV with 80 PPI density, the transistor size is approximately 0.001 mm2.

Technology trends TFT-LCD (thin-film-transistor liquid-crystal display) is the baseline technology. MO / White OLED (organic light emitting diode) is used for larger screens. LTPS / AMOLED is used for small / medium screens. The challenges for OLED are the effect of < 1 micron particles on yield, much higher cost compared to a-Si due to increased mask steps, and moisture impact to yield for the OLED step.

Mobility limitation (FIGURE 2) is one of the key reasons for the shift to MO and LTPS to enable better viewing experience from higher resolution, etc.

The challenge to MO is the oxidation after IGZO metalization / moisture prevention after OLED step, which decreases yield. A large volume of N2O (nitrous oxide) is required for manufacturing, which means a shift in the traditional supply mode might need to be considered.

Although AMLCD displays are still dominant in the market today, AMOLED displays are growing quickly. Currently about 25% of smartphones are made with AMOLED displays and this is expected to grow to ~40% by 2021. OLED televisions are also growing rapidly, enjoying double digit growth rate year over year. Based on IHS data, the revenue for display panels with AMOLED technol- ogies is expected to have a CAGR of 18.9% in the next five years while the AMLCD display revenue will have a -2.8% CAGR for the same period with the total display panel revenue CAGR of 2.5%. With the rapid growth of AMOLED display panels, the panel makers have accel- erated their investment in the equipment to produce AMOLED panels.

There are three types of thin-film-transistor devices for display: amorphous silicon (a-Si), low temperature polysilicon (LTPS), and metal oxide (MO), also known as transparent amorphous oxide semiconductor (TAOS). AMLCD panels typically use a-Si for lower-resolution displays and TVs while high-resolution displays use LTPS transistors, but this use is mainly limited to small and medium displays due to its higher costs and scalability limitations. AMOLED panels use LTPS and MO transistors where MO devices are typically used for TV and large displays (FIGURE 3).

This shift in technology also requires a change in the gases used in production of AMOLED panels as compared with the AMLCD panels. As shown in FIGURE 4, display manufacturing today uses a wide variety of gases.

These gases can be categorized into two types: Electronic Specialty gases (ESGs) and Electronic Bulk gases (EBGs) (FIGURE 5). Electronic Specialty gases such as silane, nitrogen trifluoride, fluorine (on-site generation), sulfur hexafluoride, ammonia, and phosphine mixtures make up 52% of the gases used in the manufacture of the displays while the Electronic Bulk gases–nitrogen, hydrogen, helium, oxygen, carbon dioxide, and argon – make up the remaining 48% of the gases used in the display manufacturing.

The key ga susage driver in the manufacturing of displays is PECVD (plasma-enhanced chemical vapor deposition), which accounts for 75% of the ESG spending, while dry etch is driving helium usage. LTPS and MO transistor production is driving nitrous oxide usage. The ESG usage for MO transistor production differs from what is shown in FIGURE 4: nitrous oxide makes up 63% of gas spend, nitrogen trifluoride 26%, silane 7%, and sulfur hexafluoride and ammonia together around 4%. Laser gases are used not only for lithography, but also for excimer laser annealing application in LTPS.

Silane: SiH4 is one of the most critical molecules in display manufacturing. It is used in conjunction with ammonia (NH3) to create the silicon nitride layer for a-Si transistor, with nitrogen (N2) to form the pre excimer laser anneal a-Si for the LTPS transistor, or with nitrous oxide (N2O) to form the silicon oxide layer of MO transistor.

Nitrogen trifluoride: NF3 is the single largest electronic material from spend and volume standpoint for a-Si and LTPS display production while being surpassed by N2O for MO production. NF3 is used for cleaning the PECVD chambers. This gas requires scalability to get the cost advantage necessary for the highly competitive market.

Nitrous oxide: Used in both LTPS and MO display production, N2O has surpassed NF3 to become the largest electronic material from spend and volume standpoint for MO production. N2O is a regional and localized product due to its low cost, making long supply chains with high logistic costs unfeasible. Averaging approximately 2 kg per 5.5 m2 of mother glass area, it requires around 240 tons per month for a typical 120K per month capacity generation 8.5 MO display production. The largest N2O compressed gas trailer can only deliver six tons of N2O each time and thus it becomes both costly and risky

Nitrogen: For a typical large display fab, N2 demand can be as high as 50,000 Nm3/hour, so an on-site generator, such as the Linde SPECTRA-N® 50,000, is a cost-effective solution that has the added benefit of an 8% reduction in CO2 (carbon dioxide) footprint over conventional nitrogen plants.

Helium: H2 is used for cooling the glass during and after processing. Manufacturers are looking at ways to decrease the usage of helium because of cost and availability issues due it being a non-renewable gas.

N2 On-site generators: Nitrogen is the largest consumed gas at the fab, and is required to be available before the first tools are brought to the fab. Like major semiconductor fabs, large display fabs require very large amounts of nitrogen, which can only be economically supplied by on-site plants.

Individual packages: Specialty gases are supplied in individual packages. For higher volume materials like silane and nitrogen trifluoride, these can be supplied in large ISO packages holding up to 10 tons. Materials with smaller requirements are packaged in standard gas cylinders.

In-fab distribution: Gas supply does not end with the delivery or production of the material of the fab. Rather, the materials are further regulated with additional filtration, purification, and on-line analysis before delivery to individual production tools.

The consumer demand for displays that offer increas- ingly vivid color, higher resolution, and lower power consumption will challenge display makers to step up the technologies they employ and to develop newer displays such as flexible and transparent displays. The transistors to support these new displays will either be LTPS and / or MO, which means the gases currently being used in these processes will continue to grow. Considering the current a-Si display production, the gas consumption per area of the glass will increase by 25% for LTPS and ~ 50% for MO productions.

To facilitate these increasing demands, display manufacturers must partner with gas suppliers to identify which can meet their technology needs, globally source electronic materials to provide customers with stable and cost- effective gas solutions, develop local sources of electronic materials, improve productivity, reduce carbon footprint, and increase energy efficiency through on-site gas plants. This is particularly true for the burgeoning China display manufacturing market, which will benefit from investing in on-site bulk gas plants and collaboration with global materials suppliers with local production facilities for high-purity gas and chemical manufacturing.

Munich, Germany, 1 November 2011 – Linde LienHwa (LLH), The Linde Group"s joint venture with LienHwa MiTAC Group of Taiwan, today announced a further strengthening of its commitment to the TFT-LCD industry in China with the opening of a major ultra-high purity gas plant at BOE Technology Group Co. Ltd"s (BOE) latest 8.5 generation TFT-LCD manufacturing facility in the Beijing Development Authority. The significant facility investment is part of the Chinese government’s first endorsed project aimed at boosting the country’s TFT-LCD industry.

Andrew Lau, President and General Manager of Linde LienHwa in China, said: "This new plant strengthens our position as a leading gas supplier for the electronics industry in China, and demonstrates the increasing demand for our gases from electronics manufacturers looking for the most technologically advanced, cost effective and environmentally sustainable solutions."

The on-stream supply marks a significant milestone in the cooperation between LLH and BOE, a leading TFT-LCD panel manufacturer for televisions, mobile devices and display light products, and follows the 15-year bulk gas supply contract and electronic gas agreements signed in 2010 and 2011.

Very large volumes of ultra-high purity gases play a critical part in the manufacture of TFT-LCD technologies. They are used to create the microscopic thin-film transistors required to control each of the thousands of pixels that make up the visible image.

The new facility developed by LLH consists of an installation of the plant’s bulk gases supply systems, including on-site nitrogen plants including one SPECTRA-N 30,000 series ultra-high purity nitrogen generator, the biggest of its type in China. This allows the supply of 30,000Nm3/hour of nitrogen via an underground pipeline. LLH has also constructed high capacity liquid nitrogen storage tanks and storage and supply systems for other gases on the site, including oxygen, hydrogen and argon.

The growing local demand has made China a preferred manufacturing destination for TFT-LCD technologies, supported by several initiatives by the Chinese government. Government support also includes direct investment which was a key driver for BOE in this installation.

According to DisplaySearch, China is the top TV market contributing to 17 percent of the global TV shipments by Q2 2011. Production capacity in China is expected to grow at a Compound Annual Growth Rate (CAGR) of 60 percent between 2010 and 2014, increasing China’s share by more than double. BOE is contributing significantly to this growth.

The on-stream supply at BOE"s latest 8.5 generation TFT-LCD manufacturing facility reinforces Linde’s leading position in bulk gases supply business to Chinese electronics customers and expands LLH’s footprint in the Greater Beijing region where several significant growth opportunities are expected.

About Linde LienHwa (LLH) Linde LienHwa (LLH), a joint venture in mainland China between The Linde Group and LienHwa MiTAC Group of Taiwan, is dedicated to the supply of ultra-high purity gases and the delivery of engineering projects and services to the semiconductor, TFT-LCD, photovoltaic and LED industries. LLH provides Chinese industries with a powerful combination of local infrastructure and technology from the market leader in gases and chemical supply.

About The Linde Group The Linde Group is a world-leading gases and engineering company with around 50,000 employees working in more than 100 countries worldwide. In the 2010 financial year, it achieved sales of EUR 12.868 bn. The strategy of The Linde Group is geared towards long-term profitable growth and focuses on the expansion of its international business with forward-looking products and services.

About BOE BOE Technology Group Co. Ltd (BOE) is a China-based company primarily engaged in research, development, the manufacturing and sale of thin-film transistor liquid crystal displays (TFT-LCD). BOE provides TFT-LCD products for information technology devices, televisions, mobile and application products and display light products among other display formats. Over the past 10 years, BOE has become one of the largest producers of liquid crystal displays in China.

Flat-panel displays are thin panels of glass or plastic used for electronically displaying text, images, or video. Liquid crystal displays (LCD), OLED (organic light emitting diode) and microLED displays are not quite the same; since LCD uses a liquid crystal that reacts to an electric current blocking light or allowing it to pass through the panel, whereas OLED/microLED displays consist of electroluminescent organic/inorganic materials that generate light when a current is passed through the material. LCD, OLED and microLED displays are driven using LTPS, IGZO, LTPO, and A-Si TFT transistor technologies as their backplane using ITO to supply current to the transistors and in turn to the liquid crystal or electroluminescent material. Segment and passive OLED and LCD displays do not use a backplane but use indium tin oxide (ITO), a transparent conductive material, to pass current to the electroluminescent material or liquid crystal. In LCDs, there is an even layer of liquid crystal throughout the panel whereas an OLED display has the electroluminescent material only where it is meant to light up. OLEDs, LCDs and microLEDs can be made flexible and transparent, but LCDs require a backlight because they cannot emit light on their own like OLEDs and microLEDs.

Liquid-crystal display (or LCD) is a thin, flat panel used for electronically displaying information such as text, images, and moving pictures. They are usually made of glass but they can also be made out of plastic. Some manufacturers make transparent LCD panels and special sequential color segment LCDs that have higher than usual refresh rates and an RGB backlight. The backlight is synchronized with the display so that the colors will show up as needed. The list of LCD manufacturers:

Organic light emitting diode (or OLED displays) is a thin, flat panel made of glass or plastic used for electronically displaying information such as text, images, and moving pictures. OLED panels can also take the shape of a light panel, where red, green and blue light emitting materials are stacked to create a white light panel. OLED displays can also be made transparent and/or flexible and these transparent panels are available on the market and are widely used in smartphones with under-display optical fingerprint sensors. LCD and OLED displays are available in different shapes, the most prominent of which is a circular display, which is used in smartwatches. The list of OLED display manufacturers:

MicroLED displays is an emerging flat-panel display technology consisting of arrays of microscopic LEDs forming the individual pixel elements. Like OLED, microLED offers infinite contrast ratio, but unlike OLED, microLED is immune to screen burn-in, and consumes less power while having higher light output, as it uses LEDs instead of organic electroluminescent materials, The list of MicroLED display manufacturers:

Sony produces and sells commercial MicroLED displays called CLEDIS (Crystal-LED Integrated Displays, also called Canvas-LED) in small quantities.video walls.

LCDs are made in a glass substrate. For OLED, the substrate can also be plastic. The size of the substrates are specified in generations, with each generation using a larger substrate. For example, a 4th generation substrate is larger in size than a 3rd generation substrate. A larger substrate allows for more panels to be cut from a single substrate, or for larger panels to be made, akin to increasing wafer sizes in the semiconductor industry.

"Samsung Display has halted local Gen-8 LCD lines: sources". THE ELEC, Korea Electronics Industry Media. August 16, 2019. Archived from the original on April 3, 2020. Retrieved December 18, 2019.

"TCL to Build World"s Largest Gen 11 LCD Panel Factory". www.businesswire.com. May 19, 2016. Archived from the original on April 2, 2018. Retrieved April 1, 2018.

"Panel Manufacturers Start to Operate Their New 8th Generation LCD Lines". 대한민국 IT포털의 중심! 이티뉴스. June 19, 2017. Archived from the original on June 30, 2019. Retrieved June 30, 2019.

"Business Place Information – Global Operation | SAMSUNG DISPLAY". www.samsungdisplay.com. Archived from the original on 2018-03-26. Retrieved 2018-04-01.

"Samsung Display Considering Halting Some LCD Production Lines". 비즈니스코리아 - BusinessKorea. August 16, 2019. Archived from the original on April 5, 2020. Retrieved December 19, 2019.

Herald, The Korea (July 6, 2016). "Samsung Display accelerates transition from LCD to OLED". www.koreaherald.com. Archived from the original on April 1, 2018. Retrieved April 1, 2018.

Byeonghwa, Yeon. "Business Place Information – Global Operation – SAMSUNG DISPLAY". Samsungdisplay.com. Archived from the original on 2018-03-26. Retrieved 2018-04-01.

Colantonio, Andrea; Burdett, Richard; Rode, Philipp (2013-08-15). Transforming Urban Economies: Policy Lessons from European and Asian Cities. Routledge. ISBN 9781134622160. Archived from the original on 2019-01-01. Retrieved 2019-06-09.

"China"s BOE to have world"s largest TFT-LCD+AMOLED capacity in 2019". ihsmarkit.com. 2017-03-22. Archived from the original on 2019-08-16. Retrieved 2019-08-17.

China. The production increase is due in part to the switch to digital television which will lead to increased LCD consumption and the disposal of older sets, some of them early LCD models.

environmental impacts of their LCD displays. Lenovo has nearly a dozen EPEAT gold certified displays to offer and Phillips made news with their Eco TV

Over the course of the past half decade, the television has gradually become a standard American household item, to the point where it is not uncommon for a household to own more than one television. As with any object made for human consumption, the television requires materials from an earth that can only provide a finite amount of such things. These materials come from many different sources, from many different areas of the world, and are all assembled into the different working parts that make up a television. The materials as they are found raw in nature range from argon gas to platinum ore, and many raw materials are then combined into other secondary materials that are then assembled into the parts of the television. Televisions depend on a wide range of these naturally found materials to be produced, but the main kinds of materials that make up a television are secondary materials produced from the combination of various raw materials, which makes the different parts of the life cycle of a television each more complex.

The raw materials that are extracted for use in a television come from many different sources, which makes the beginning of the television’s life cycle one that starts at many different places. One of the main types of materials used in televisions are plastics, namely thermoplastics such as polyethylene. Thermoplastics like polyethylene are used because they can be melted down and remolded repeatedly, which is part of the process in making the exterior casing of a television. Polyethylene is made from the polymerization of ethylene. Ethylene is produced from the cracking of ethane gas, which can be separated from natural gas. When the polyethylene is ready, it is molded into the specific shape that is required to encase a television, and is then set into that shape by using a thermoset. The thermoset is used to fix the meltable plastic in the shape that the plastic has been molded in, meaning that once the thermoset is fixed onto the plastic, the plastic cannot be melted again. The fixing of thermosets is necessary for electronic appliances like televisions that produce a significant amount of heat, so that the plastic that encases the television will not melt down. The most common thermoset used in televisions is urea formaldehyde. Urea formaldehyde is made by obtaining urea, a solid crystal, from ammonia gas, and by obtaining formaldehyde from methane gas. The two are then chemically combined to make the resin-like material that is used as a thermoset. Another main material that is used in most television is glass. Glass is the essential material that makes up the screen of a television, and is made from the chemical compound silicon oxide. All these materials are extracted and made in factories spread throughout the world, adding to the complexity of manufacturing televisions.

While plastics and glass are the main materials that make up the exterior of a television, the interior parts of a television are made up of a greater range of materials. Plastics are also used in the interior of a television, but inside of a television are also found gases and minerals. Gases such as argon, neon, and xenon gas fill the television screen for the purpose of projecting colors into the screen, and are made visible by the phosphor coating that coats the inside of a television screen. Glass and lead are also found inside of a television screen. These two materials make up cathode ray tubes, which are the video display components of a television. Other components that are found inside of a television also require thermoplastics like polyethylene, including components such as light valves, which work together with cathode ray tubes to enable the electrons inside to be visible on screen. The main electrical components on the interior of a television require a large amount of silicon; these include components such as the logic board, circuit boards, and capacitors. Once again, these materials are extracted and processed on several different continents. Silicon can be found in many different places, but a large supply comes from California. Meanwhile, many plastics are manufactured in China, while factories in the United States manufacture glass. These materials can be manufactured or extracted in other countries as well, which also helps to make the life cycle of a television a complex and global circle.

After these materials are all extracted, they must be processed so that they can make up a television. The main process that affects the raw material usage of a television is the injection molding process. This process is where all the plastics, specifically thermoplastics, that are used in a television are put together and shaped, essentially bringing many of the materials that were extracted for use in the television together. The plastics that will be shaped into television parts are ran through an assembly line of sorts in a factory. They are then melted down into molten plastic and poured into a mold matching the shape that the plastic is desired to conform to. Once that plastic has set in the mold, the thermoset is applied to ensure that the plastic will not melt down again. Thus, much of the materials that eventually go towards use in a television are applied and shaped into their desired form during this process. However, many more materials still need to be added in order to make the final product, and while plastics make up a large part of a television, there are still gases, minerals, and additional synthetic materials such as glass that must come together. The large spread of materials that need to be extracted to make up a television, and the array of locations that those materials are extracted and processed in, contribute towards making the life cycle of a television difficult to track.

Once the materials that will make up the television have been extracted and processed, the assembled television is ready to be distributed. Once again, the distribution process of televisions is spread out all around the world. In the case of Americans, televisions are no longer manufactured in the United States. This means that the televisions must be shipped oversea to the United States, which is done by both plane and boat. Thus, the diesel fuel used to power both planes and cargo boats are used as raw materials in the life cycle of a television. The diesel fuel used in planes and cargo boats are usually kerosene based, which is obtained by distilling petroleum. Additionally, when the televisions get to the United States, they must be distributed by means of shipping trucks, which means the natural gasoline that they use are another addition to the raw materials that are involved in the life cycle of a television. As a final step in the distribution process, the televisions are usually packaged in cardboard boxes, which are commonly made from recycled paper. More plastic is then used to protect the television in the form of protective wrap such as bubble wrap. Bubble wrap is also made from the polyethylene that makes up many components of the television, making plastic a material that is essential to every stage thus far of the life cycle of a television, as well as being a material that makes the life cycle difficult to analyze.

Once the televisions reach the home of Americans, an additional stage of raw materials usage takes place. To install and properly use a television, additional items must be used in tandem with the aforementioned television. The television must be plugged into power using wires and power outlets, which use metal and polyethylene plastic, respectively. Specifically, most wires that power televisions are made from copper, as copper is a relatively cheap conductive metal. Televisions are also commonly used in tandem with TV remotes and DVD players. TV remotes are also mainly made from plastic. The plastic most commonly used in TV remotes is a thermoplastic polycarbonate made from acrylic plastic, which is turn derived from a chemical compound made out of carbon, hydrogen, and oxygen that produces acrylic acid. The additional components used in a TV remote use largely the same materials as the additional components in the main television, such as silicon. On the same note, DVD players use largely the same materials as a television. DVD players use a fair amount of thermoplastics as well for the outer casing, as well silicon for many of the interior components. Here again, plastic made all over the world is one of the main materials used to fuel the life cycle of a television, leading to the diffusion of many specifics regarding how exactly a televisions’ life cycle comes together.

After installation and the acquirement of accessories, televisions can last for a relatively long time without the need for frequent maintenance. However, when it is time for a television to be replaced, the process of doing away with the old television can be messy. Televisions are illegal to place into dumps in many states because of the hazardous mixture of gases and lead that they contain. Because of this toxic mixture of gases and lead, the majority of televisions are unable to be recycled. The specific way that the materials are combined do not allow for recycling without significant health risks to those people handling the recycling. Due to the hazards that recycling televisions pose, many televisions end up either being placed in dumps with nothing being done to them or being unused around homes. Currently, there are many researchers and research institutes attempting to try and solve this problem, such as a recent experiment done at Purdue University trying to extract the toxic materials out of the television in a cost-effective and efficient manner that still preserves the plastic for recycling. Many of these studies were done about three to five years ago, and as of yet, there is still no concrete solution to the problem of recycling electronic waste such as a television. However, progress in the form of ongoing experimentation is still being made toward a solution for effective electronic waste management.

As that progress is being made, televisions remain one of the main representations of the new digital age. They were one of the first digital products that were able to be distributed commonly across America, and ushered in a new era of consumerism. As of yet, it seems that humanity will have the means to make televisions for the long foreseeable future, though it remains to be seen how the complex life cycle of the raw materials used in a television will affect the planet.

Televisions are globally one of the dominant selling products in the technology sector. China is the primary manufacturer, being home to many of the preeminent selling TV companies such as TCL, Skyworth and others that partner with Chinese manufacturers such as Samsung and LG. Although the number of televisions that are produced per year is not a record the public has access to, it is estimated that there are seven-hundred and fifty-nine point three million TV sets connected worldwide in 2018 [14]. The cradle-to-grave of television production has five steps: the acquisition of raw and synthetic materials, the manufacturing process, the distribution and transportation, the use of televisions, and the disposal and recycling [9]. Energy application is present in each of the five stages of the complete life cycle of televisions, specifically the Liquid Crystal Display (LCD) model. The entire life cycle of televisions uses and produces energy that is not environmentally safe to human and animal health and the atmosphere. Even though television companies claim to be decreasing the environmental consequences, the immense presence of energy use throughout the cradle-to-grave of television production continue to result in hazardous effects.

The first step of the television life cycle, the acquisition of the materials, produces and uses the largest amount of energy of the steps. The acquiring process of the materials includes obtainment, collection, extraction, combination, and transformation of the raw and synthetic materials. The main materials are plastics, circuits, circuit boards, glass, metals and various materials such as indium-tin oxide and liquid crystal. Plastics make up the exterior pieces and layout of the television, as well as a fewer small pieces inside. Plastic is formed from crude oil or natural gas like fossil fuels, which have to first be mined from the earth’s core and then must be processed before the polymerisation process can be carried out. This process is used to chemically combine carbon monomers in order to form carbon polymers which make up plastic and give it it’s individual properties. Overall, plastics require motion energy and electricity to be mined and chemical energy to turn oil or natural gas into plastic. Circuits make up the various circuit boards along with minor metal or plastic pieces. The circuits are originally made of silicon dioxide, or silica, which must be extracted from the earth’s crust. More modernly, silica is being replaced by quartz by some manufacturing companies. Silica and quartz are both extracted from the earth using electricity and thermal energy through mining and extraction. Silicon dioxide is used in the circuit boards because it is a semiconductor, so it must be processed with drilling or thermal techniques to obtain the desired shape and form. The obtainment of materials for the circuits involves thermal energy and electricity through the multiple steps. Silicon dioxide is also the main component in glass which is made from heating sand or quartz with waste glass and soda ash into a liquid mixture to be molded into the desired solid shape. Thermal energy is the prime energy source in the transformation process of glass, but also the minor electricity source for the silica. The various metals that are found scattered through modern televisions include gold, lead and copper. Each of these metals must be mined and extracted from the earth requiring electricity and thermal energy must be applied in order to change the form into liquid to modify the shape for parts. Liquid crystal that is used in the Liquid Crystal Display (LCD) panels is found in various mineral forms and must be extracted using electricity. Indium-tin oxide (ITO) is “a scattered and rare element” that is found in the Earth’s crust, but is “challenging to [extract]” [4]. It actually does not exist as an ore itself but it is “mainly produced as a by-product of zinc mining” or lead mining [11]. The zinc and lead are mined using electricity and then using smelting techniques, which apply thermal energy, indium-tin oxide is processed out of the ores. The collection of the materials involves the extensive energy application of the varying types of energy. Once the materials are acquired, the manufacturing stage begins and the precarious energy utilization continues to grow.

The manufacturing phase applies the second most impactful energy use behind the first step, emitting hazardous effects in large, concentrated volumes. The production processes vary by manufacturer, but they generally contain assembly lines, machine tools and technology, automated robots and packaging. The plastic parts found throughout the structure and the inner parts are made using the well-adopted injection molding process. This process uses thermal energy to liquify plastic in order to be injected into the definite molds [5]. After they cool, they must be cut and sized-down to perfection with saws and cleaned manually for safety as well as appeal [5]. This requires electricity to function the saws and kinetic energy in human movements for the manual work [9]. The LCD panels are composed of a variety of substances and materials, the most prominent being indium-tin oxide, liquid crystal and metal pieces [2]. The panels are manually made adding the liquid crystal layer, the ITO layer and a few other metal and glass layers using either adhesives or screws to connect them all together. This process of building the LCDs exerts immense kinetic and mechanical energy by human labor. The glass flat screen for the television must be laser-cut to shape utilizing thermal energy and electricity. All of this electricity and thermal energy that is used in manufacturing requires incredible amounts of coal or fossil fuel consumption. The greenhouse gas emissions (GHG) resulting from the energy application are inordinately unsafe for the Earth in the short and long term. They are destroying our atmosphere which can damage plant life and harm the human and animal health. The manufacturing phase, although it is the second step most in energy consumption and emission, the concentrated levels of emission make it detrimental nonetheless. This stage includes the packaging and loading of the finished television sets in order to be ready for the next step, transportation and distribution worldwide.

Television companies sell their products across their country, continent and even overseas; the transportation systems used to accomplish this apply a sizable quantity of energy consumption. Aircrafts, automobiles, and ships are the most efficient means of distributing televisions to consumers. Fossil fuels, ranging in quantity, are what fuel the combustion engines inside all of the transportation services. Chemical energy is applied inside the engines to convert the fuel into mechanical energy to propel the truck, ship or airplane forward [8]. Efficient fuel consumption is still being studied for vehicles, airplanes and ships in order to decrease the energy intensiveness (EI) [8]. The EI includes many factors such as speed, to travel longer distances, carry more weight and be as environmentally safe as possible[8]. Combustion engines release GHG emissions dire to the atmosphere causing problems related to the health of the populations on Earth. Human labor is the other, non GHG emitting, component to move the TV products the shorter distances such as from the manufacturing factory to the trucks to the plane or ships to the stores that then sells them to consumers. The human interaction with the transportation stage only entails kinetic energy. Transportation is also employed in the acquisition of materials stage to move the inputs from the site to factories and the disposal and recycling stage from consumers to the facilities. Energy conservation of means of transportation is intensively studied to lower the consumed energy and the GHG emissions, but a permanently sustainable solution has not been discovered yet.

Televisions notoriously require electricity to function, which entails an incomparable utilization of coal, natural gas or solar sources. The average household in developed countries has at least one connected television set, but many have numerous. Televisions are used in many other settings such as public places like hospitals, restaurants, schools, stores, salons, arenas and even transportation services more modernly, like airplanes, cars and trains. The absurd amount of TVs used around the world necessitates the massive ratio of natural gas and coal. Solar power for electricity is accessible but is not a widely adopted method. The burning of natural gases and coal for electricity exudes GHG emissions, obviously detrimental consequences to the environment. The consumer use stage, though it’s embodied energy is hazardous to Earth and its inhabitants, it is minor in the comparison of manufacturing and procurement of materials. A larger concern with televisions is the end-of-life care after consumers desire upgrades or replacements.

TV sets inevitably must be replaced, but disposal techniques are still being experimented in terms of safety, procurement of materials and the energy application, including the effects. If televisions are not recycled and disposed properly, the materials can leak into the ground contaminating clean water systems and the plant life or harm humans who do not disassemble the TVs safely [6]. The best method for dismantling has proven to be to retrace the manufacturing process backwards to disassemble it most cost-effectively and with the most recovery of materials [12]. A comprehensive study by Ardente and Mathieux (2014) initiated an ideal method that consists of five steps to dismantle LCD panels as well as other electronic devices: “reusability, recyclability, recoverability, recycled and use of hazardous substance” [15]. Experiments to retrieve and reuse all of the materials have yet to be successful, but a few of the materials have favorable results including plastics, precious metals, glass and ITO. The basis of the disassembly from LCD panels has the highest efficiency when dismantled and extracted manually rather than mechanically which applies large amounts of kinetic and mechanical energy [1]. The numerous plastic parts are best recycled using two techniques: energy recovery (or thermal recycling) and mechanical recycling (or material recycling) [10]. Energy recovery is incineration of plastic waste to be used as electricity involving kinetic and mechanical energy by manual labor, but mostly uses electricity and thermal energy to incinerate the plastics[10]. Mechanical recycling is plastic waste being recycled into other resources utilizing kinetic or mechanical energy by manual labor as well as potential energy and gravitational energy of the materials [10]. Precious metals and glass both use kinetic, mechanical and thermal energies to be extracted manually, crushed down and then typically sold to be melted down to reform for other products. Indium-tin oxide is the most recycled raw material in LCD panels and can be fully extracted by numerous techniques encompassing leaching [11], sorption [4], and pyrolysis [1]. These each include exposing the LCD panels to varying chemicals, high temperatures and a range of pressures [4]. Overall, the recovery of ITO by means of recycling involves intensive chemical, thermal and pressure energies. This final stage of disposal and recycling of LCD televisions has the most exposure to research and experimenting. It encompasses the second highest levels of energy application, relatively identical to the manufacturing phase, but there is vast potential to lower this energy consumption and waste to a more environmentally friendly approach.

The life cycle analysis of televisions is years from being complete; the manufacturer companies do not give public access to the details of each step yet and there has not been an abundance of research. The embodied energy is the least investigated aspect of the life cycle of television sets. Televisions, being abundantly produced and sold to consumers, are constantly being upgraded in terms of design, environmentally friendly, and energy capacity. Recycling of the raw materials, as well as plastics and glass, is being experimented with the most. Indium is the most prominent to be extracted and reused for more technology since indium is being mined at a rate that is running out. Television companies are competing to find safer procedure to carry out all five steps of the cradle-to-grave of TV sets. The main take away from this analysis: energy that is used and produced from the life cycle is still hazardous to the environment and the health of humans and animals. If TV manufacturer companies do not find new techniques for the acquisition of raw and synthetic materials, the manufacturing process, the distribution and transportation, the use of televisions, and the disposal and recycling, we will run out of materials and further destroy the atmosphere and the human and animal health.

[4]Assefi, Mohammad, et al. "Selective recovery of indium from scrap LCD panels using macroporous resins." Journal of Cleaner Production 180 (2018): 814-822.

[7]Curran, Mary Ann. "Life cycle assessment: a review of the methodology and its application to sustainability." Current Opinion in Chemical Engineering 2.3 (2013): 273-277.

[12]Ryan, Alan, Liam O’Donoghue, and Huw Lewis. "Characterising components of liquid crystal displays to facilitate disassembly." Journal of cleaner Production 19.9-10 (2011): 1066-1071.

The manufacturing of televisions has continuously been monitored as a part of the life cycle assessment in the modern day society. A television is simply a machine powered by electricity that displays images on a screen and sounds out of the speakers. Current models of TVs are mainly focused on the LCD TV, which is a liquid crystal display television. LEDs, light-emitting diodes, are the source for illuminating light by the movement of electrons on a semiconductor that gives off the variation of colors behind the display. Creating the televisions by incorporating LEDs and additional metal elements into a contained liquid crystal display with a plastic frame is the main concept for the TV. During the production of an LCD TV, the detrimental effects to the environment of the waste and emissions such as greenhouse gases from the materials of the metals can be observed through the assembly process of the television and the disposal of the substances.

As the amount of TVs are increasing for demand, the air pollution worsens in relations to the increase of metals for compact designs of the monitors. In the initial phase, the screen is created with silicon oxide and indium tin oxide that are used for polishing the glass layers. The silicon oxide is a colorless material consisting of quartz as the main ingredient while the indium tin oxide is a yellow colored substance that acts as a coating for clearness. According to the Laboratory Chemical Safety Summary, the National Institutes of Health states that silicon dioxide “may cause mechanical irritation to the eyes, respiratory tract and skin” (U.S. National Library of Medicine, 2008). The substance is hazardous as a solid form of dust particles that can be inhaled through the air. Though, silicon dioxide is applied to the glass screens in a liquid form ,which is not toxic to the workers, to smoothen the surface and correctly position the liquid crystals. Air borne inhalation of the chemical is not as harmful as the physical contact with the substance itself. Therefore, factories enforce workers to wear protective gear from the head to feet to prevent exposure to the liquids. Likewise, the indium tin oxide is cautioned with safety equipment and masks. In the Chemical Information Profile by the U.S. Department of Health and Human Services, indium tin oxide, ITO for short, also “may cause severe irritation and burns to the skin or eyes” (U.S. Department of Health and Human Services, 2009). Similarly, the substance is effective in a powdered form that may cause lung infection through inhalation. The screen is then made more transparent with ITO in a liquid state. Both substances obtain a fine quality of a glass screen and are not considered devastating to the surrounding. However, ingesting and direct contact with the chemicals can be severe with the side effects in mind. Refining the glass is not the most detrimental of the process but still requires attentive measures to prevent a high accumulation of the liquids.

Another substance that is harmful to the environment within the procedure mainly revolves around the nitrogen trifluoride on the LCD television. Nitrogen trifluoride is the main component for allowing the surfaces of the TV to be water and fingerprint resistant. The substance is physically applied by the hands of human workers. By adding on the substance to the screen, the fumes released in the factories are vacated through vacuums that lets the gas into the atmosphere of the earth. Otherwise, the chemicals may be trapped within the factories during production. The National Institutes of Health evaluated that the symptoms of inhaling nitrogen fluoride affects the “blood, liver, and kidneys” and targets humans and animals such as “dogs, monkeys, and rats” (U.S. National Library of Medicine, 2018). While workers wear a suit and gloves to protect themselves from the fumes in the factories, the concentration of the gas remains toxic to wildlife that breathe on land. Although the process of coating the glass pieces are done in a sealed room to prevent leakage of the scent from the nitrogen trifluoride to the rest of the factory, the outer perimeter of the buildings are not safe to breathe. In The Guardian, a report from Michael Prather, the director of the environment institute at the University of California, Irvine notes that “as a driver of global warming, nitrogen trifluoride is 17,000 times more potent than carbon dioxide” (Sample, 2008). Carbon dioxide is already a major role played in polluting the atmosphere including the carbon emissions of the trucks during the shipment process. The amount of nitrogen trifluoride released is not a widespread issue with the concentration from the substance being contained. However, the growth is noticeable that nitrogen trifluoride is listed as a major “greenhouse gas” reported from Michael Prather in the Four Materials Illustrate Hazards Of Electronics Manufacturing (Gordon, 2017). Additionally, the composition of the air quality depicts a growing accumulation of the gas as the development of monitors of the television continue to flourish. Nitrogen trifluoride is a crucial factor to protecting and prolonging the televisions’ lifespan but contains a cost that endangers humans and animals.

In the creation of the LCD TV, there are waste factors that take place in removing the product after its lifespan. The plastic frame of the television is salvageable such that the product can be melted and reused again. But, metal components and chemicals that are built upon the circuit boards and monitors remain difficult to reattain the materials. In fact, recycling the flat-screen TV is not possible with another material within the components of the circuit boards, which is mercury. Denise Wilson of the WEEE: Waste Electrical and Electronic Equipmentreports that “inhaling mercury can lead to a myriad of behavioral and neurological problems such as insomnia, memory loss, tremors, and cognitive dysfunction” (Wilson, 2016). Even a low concentration of mercury is fatal for humans to take in while attempting to dismantle the television for deconstruction. Since the materials are not replaceable through recycling the LCD TVs, material costs are risen due to the rarity of finding the natural raw materials such as gold, silver, and copper for the circuit boards. Other materials that include indium tin oxide are nonrenewable which also limits the maximum amount of TVs produced. Furthermore, removing the metals from the television has a drawback of releasing toxicity. Wilson adds that dioxins exposed from deconstructing LCD TVs “lead to impairment of the endocrine, immune and reproductive systems as well as alter liver function” (Wilson, 2016). Dioxins are a pollutant to the air that is toxic for humans to inhale. The collective chemicals can be seen through both the production for the screen and the elimination of the product after usage. To prevent the releases of the gases into the air, depleted televisions are brought into specialized recyclers to harvest the remains of the electronics. Despite the efforts of replenishing the components, factories that melt away the components are still in existence to removing the waste. According to the author of Recycle Nation, Sophia Bennett states that “as televisions are run over by crushing equipment in a landfill, or burned in an incinerator, they release those heavy metals that can seriously affect human health” (Bennett, 2014). The physical process of “crushing” the materials is a wasteful method of removing the scarce resources from the circuit boards. Meanwhile, the chemical process of burning the metals secretes carbon and dioxin emissions and leaves solid wastes of mineral compounds. With that in mind, the electronic device must carefully be readjusted to contain friendly environmental substances that are reusable and reduce the harmful symptoms to the atmosphere.

Transporting the product of the LCD TVs also contributes to the pollution of the environment with greenhouse gases after the assembly is finished. In the delivery phase, the televisions are encased in large cardboard boxes and can be shipped to designated locations on land, water, and air. Trucks, ships, and planes all produce carbon dioxide as fuel is burned within the respective engines for the mobile vehicles. For instance, the internal combustion engine for trucks burns diesel fuel to power the pistons while the ships use coal to supply energy to the propulsion engines. Planes have the similar effect with the design of an engine that requires diesel fuel or gas. The modes of transportation mentioned beforehand increase in relations to the rising production of LCD TVs for consumers which results in a higher output of carbon dioxide as well. Thus, the carbon emissions from transporting the television is observed as a factor of damaging the ecosystem from the shipment process of the vehicles.

In essence, acknowledging the existence of the chemical substances released into the atmosphere from the waste and emissions of manufacturing and deconstructing an LCD TV is crucial for an understanding of the environmental impact it has on humans and the wildlife. As the production of televisions continue to develop the flat screen panels that incorporate toxic materials, more waste is produced as a result of the amount of TVs needed for the increase in supply and demand. In fact, electronic devices that focus heavily upon the usage of the chemical substances involves not only televisions but any creations with screens and monitors. Recording the findings of the symptoms from the chemical activities within the factories and the atmosphere allow producers and consumers to identify safer and more reliable resources that reduces the harm to the environment and life on earth. The life cycle of the television remains as an important subject for careful observations of the advancements developed upon electronic devices towards the future.

“Chemical Information Profile.” National Toxicology Program, U.S. Department of Health and Human Services, June 2009, ntp.niehs.nih.gov/ntp/noms/support_docs/ito060309_508.pdf.

“F-GHG Emissions Reduction Efforts: Flat Panel Display Supplier Profiles.” F-GHG Emissions Reduction Efforts: Flat Panel Display Supplier Profiles, U.S. Environmental Protection Agency, May 2013, www.epa.gov/sites/production/files/2017-09/documents/supplier_profiles_fy2011.pdf.

“Nitrogen Trifluoride.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, pubchem.ncbi.nlm.nih.gov/compound/nitrogen_trifluoride#section=Top.

“Silicon Dioxide.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, pubchem.ncbi.nlm.nih.gov/compound/Silica#datasheet=lcss§ion=Threshold-Limit-Values.

Thank you for your letter and editor"s attention to our manuscript, entitled “Will China"s fertilizer use continue to decline? Evidence from LMDI analysis based on crops, regions and fertilizer types”(PONE-D-20-12238). The comments are valuable and have been very helpful for revising and improving this study. In accordance with the requirements of PLOS ONE and the opinions of the reviewers, I revised the manuscript again. In addition, after discussion by all authors, I have adjusted the order of authors. On behalf of my colleagues and myself, I am resubmitting the manuscript to your journal. The main corrections to the paper and the responses to the comments of the academic editor and reviewers are appended below. The comments are presented in blue, and our responses are in black. The detailed changes can be found in the ‘Manuscript’ and ‘Revised Manuscript with Tracked Changes’.

Thank you for your constructive comments on our manuscript, which have helped us to further revise and improve our paper. Based on your recommendations, we have modified the manuscript carefully. Reviewer 1’s suggestions are shown in blue, and our responses are shown in black. In addition, the corresponding modifications are shown by tracked changes in the manuscript. The main corrections and the responses to the reviewer’s comments are shown as follows:

We are grateful for your constructive suggestion. We have simplified the Abstract according to your requirements and kept the key conclusions. At present, we have deleted 245 words to 176 words. The specific changes are as follows:

China implemented the Action Plan for the Zero Increase of Fertilizer Use in 2015, which led to a decrease in fertilizer use. However, Will fertilizer use continue to reduce? With data obtained from 2006 to 2017, the paper used the logarithmic mean Divisia index (LMDI) method to analyze the scale effect, intensity effect and structural effect of fertilizer use change in China from three aspects: crops, regions and fertilizer types. Our finding suggests that (1) The intensity effect was the most critical factor affecting the decline in fertilizer use in China. (2) The sowing scale and fertilization intensity of grain, vegetables and fruits had the most significant driving effect on fertilizer reduction. (3) The three effects of each region were different in space, and the eastern region contributed most to the fertilizer decrement. (4) Nitrogen fertilizer and compound fertilizer had the most considerable influence on fertilizer reduction, especially in sowing scale and fertilization intensity since 2009. The government should establish a fertilizer reduction management system, which includes scale control, intensity reduction, structural adjustment and other measures.

Thank you for this helpful suggestion. In the fifth paragraph of the Introduction and the first paragraph of the Conclusion, we have made the contributions to application of this paper more clearly. The specific changes are shown in the following red font:

Based on the existing research, the main contributions of this paper are two aspects. First, this paper expands the perspective of fertilizer research, and discusses the sources of fertilizer reduction from the perspectives of crop, region and fertilizer type. Second, this paper is the first attempt to answer the question of sustainability of fertilizer reduction in China. Therefore, the paper used LMDI method to decompose the driving factors of the change of FU in 2006-2017 from three aspects of crop, region and fertilizer type, and deeply explores the sources of fertilizer reduction in China from different perspectives. The purpose of the study is not only to provide scientific reference for better reducing usage, increasing efficiency of fertilizer and controlling the excessive use of fertilizer, but also to provide targeted policy suggestions for exploring modern fertilizer management and achieving the goal of "zero growth of FU" in China.

Based on the panel data of FU in China from 2006 to 2017, this paper used the LMDI decomposition method to analyze the SE, IE and STE of the FU decline from the three perspectives of crops, regions and fertilizer types and probed the contribution of each effect, not only to provide scientific basis for continuous reduction of fertilizer, but also to improve the management system of fertilizer reduction for policy makers and realize the reduction "Zero growth of FU" provides policy reference.

Thank you for this valuable suggestion. We have emphasized the motivation of this paper in the Abstract, the second and fifth paragraphs of the Introduction. The specific changes are shown in the following red font:

China implemented the Action Plan for the Zero Increase of Fertilizer Use in 2015, which led to a decrease in fertilizer use. However, Will fertilizer use continue to reduce? With data obtained from 2006 to 2017, the paper used the logarithmic mean Divisia index (LMDI) method to analyze the scale effect, intensity effect and structural effect of fertilizer use change in China from three aspects: crops, regions and fertilizer types. Our finding suggests that (1) The intensity effect was the most critical factor affecting the decline in fertilizer use in China. (2) The sowing scale and fertilization intensity of grain, vegetables and fruits had the most significant driving effect on fertilizer reduction. (3) The three effects of each region were different in space, and the eastern region contributed most to the fertilizer decrement. (4) Nitrogen fertilizer and compound fertilizer had the most considerable influence on fertilizer reduction, especially in sowing scale and fertilization intensity since 2009. The government should establish a fertilizer reduction management system, which includes scale control, intensity reduction, structural adjustment and other measures.

In recent years, the Chinese government has recognized the seriousness of the overuse of fertilizer. It has put forward the decision of reducing the amount of fertilizers and increasing the efficiency on the premise of stable food production growth and adequate protection of food security. In 2015, the Chinese government promulgated the Action Plan for the Zero Increase of FU, which proposed a goal of "zero growth of FU, the establishment of a scientific fertilizer management technology system, and the improvement of the scientific FU level". Then, in 2016 and 2017, Central Document No.1 noted that the "zero growth" action of fertilizer should be carried out. China"s zero-growth action in FU has achieved initial results. In 2016, China"s FU approached zero growth for the first time. FU in China declined from 60.226 million tons in 2015 to 58.59 million tons in 2017, with an annual rate of decline of 1.8% (Fig. 1). Then, will the decline in China"s FU be sustainable? Further research on this question not only helps us better explore the driving effects of China"s fertilizer reduction and influence of each effects but also provides more comprehensive reference for policymakers to continuously control the fertilizer decrement and develop a sound fertilizer reduction management system.

Based on the existing research, the main contributions of this paper are two aspects. First, this paper expands the perspective of fertilizer research, and discusses the sources of fertilizer reduction from the perspectives of crop, region and fertilizer type. Second, this paper is the first attempt to answer the question of sustainability of fertilizer reduction in China. Therefore, the paper used LMDI method to decompose the driving factors of the change of FU in 2006-2017 from three aspects of crop, region and fertilizer type, and deeply explores the sources of fertilizer reduction in China from different perspectives. The purpose of the study is not onl