Optical Film-optical Film Is in The Key Position Of The Panel Industry Chain, And The Localization Of Polarizers Has Become A Trend

Optical film-optical film is in the key position of the panel industry chain, and the localization of polarizers has become a trend

Optical film is a thin film product with optical properties in a broad sense. It is mainly divided into polarizers and optical film products used in backlight modules (BLU). The main application areas are TFT-LCD panels (approximately 20% of the total cost), polarizers It also needs to be used in OLED panels. Panel production capacity continues to shift to the mainland. On the one hand, the investment in LCD panels, especially large-size products, has increased, driving the growth of demand for optical films; on the other hand, the localization of polarizers also brings greater opportunities.

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Introduction: Overview of Thin Molds

Membrane materials can be divided into functional films (film) and selective separation membranes (membrane). The thin film material is a two-dimensional material formed by depositing atoms, molecules or ions on the surface of the substrate. Membrane materials involve a wide range of manufacturing and application fields, covering many industries such as building materials, energy conservation and environmental protection, medicine, electronics, food, transportation, energy, and chemicals. Functional film mainly refers to the film layer with specific physical and chemical properties, used for surface covering or sandwiching, emphasizing its strength properties, surface properties, optical properties, bonding properties or barrier properties, etc.; and selective separation membranes have For materials with selective separation functions, more attention is paid to the microscopic pore structure, separation mechanism and performance.

Functional film products based on polymer substrates are becoming more and more popular in various fields, especially films with optical functions. Polymer films (such as PET, PC, PMMA, PVC, TAC, etc.) have excellent optical properties and physical and mechanical properties. The implementation of additional functional coatings such as surface hardening coatings or some special functional coatings makes these polymers The functionality of thin film materials has been improved, and the application value has increased. According to different uses and functions, it can be divided into optical films, protective barrier films, electrical and electronic films, architectural films, and other special films.

Selective separation membranes have attracted much attention for their wide application in the water treatment industry. Separation membrane is a special thin-layer material with selective permeability function. It can permeate one or several substances in the fluid, while other substances cannot permeate, thus playing the role of concentration and separation and purification. . Separation membranes are widely used in seawater desalination, food concentration, wastewater treatment, oxygen-enriched air preparation, medical ultrapure water manufacturing, artificial kidney and artificial lung devices, and slow-release drugs.

As an important new material, high-performance membrane materials have received the attention and support of relevant national policies in recent years. In the "Twelfth Five-Year Plan", high-performance membrane materials were written into government documents as a special plan, and the goal of reaching 100 billion yuan within five years was put forward. The "13th Five-Year Plan" also mentions high-performance membrane materials, but compared to the "Twelfth Five-Year Plan" which focuses on market size and market share, the "13th Five-Year Plan" emphasizes the establishment of industry standards and the importance of membrane materials in energy conservation. Application in environmental protection.

1. Introduction to Optical Film

1.1 Classification of optical films: polarizers, optical films for backlight modules

Optical film refers to the preparation or coating of one or more dielectric films or metal films or a combination of these two types of films on optical elements or independent substrates to change the transmission characteristics of light waves, including light projection, Reflection, absorption, scattering, polarization and phase change. Therefore, the transmittance and reflectance of the surface of different wavebands can be adjusted by proper reference, and the light of different polarization planes can also have different characteristics.

Optical films can be roughly divided into two groups: polarizers and backlight module optical films. The main application field is TFT-LCD. LCD is mainly composed of several major components such as liquid crystal, backlight module, glass substrate, polarizer and TFT electrode. Structurally speaking, liquid crystal display devices are flat panel display devices. Its basic structure is in the shape of a multi-layer flat plate. The basic structure of a typical liquid crystal display device is mainly composed of several major components such as liquid crystal, glass substrate, polarizer and TFT electrode. Of course, different types of liquid crystal display devices may have different parts in some parts, but all liquid crystal display devices can be considered to be composed of two photolithographic substrates with transparent conductive electrodes, sandwiching a liquid crystal layer, and encapsulating them into a flat cell. A polarizer is attached to the outer surface. Among them, the optical film of the backlight module roughly includes six types: reflective film, diffuser film, ordinary prism film, multi-functional prism film, micro lens film, and reflective polarized brightness enhancement film.

Since the LCD panel itself does not have light-emitting characteristics, a light-emitting source must be added to the LCD panel to achieve the display effect. The backlight module (BLU) is the key component that provides the light source for the back of the LCD display. LCD backlight modules are mainly composed of backlight sources, optical films, adhesive products, insulating products, plastic frames, etc. Among them, various optical films are the key components of the backlight module. According to their functions, they can be mainly divided into reflectors, diffusers, prism films, light guide plates, lamp reflectors, etc.

Splitting the cost of LCD panels shows that material costs account for more than 70% of the total LCD manufacturing costs, depreciation costs account for 11%, and labor costs, indirect costs, and sales and management costs each account for 5-6%. In the cost of materials, the backlight module accounted for the highest proportion of 18.2%, the color filter accounted for 14.7%, the polarizer accounted for 9.5%, and the glass substrate accounted for 8.9%.

The cost of brightness enhancement film, diffusion film and reflective film in the backlight module accounted for 32%, 7%, and 2% respectively, and the total accounted for 41%. Among the polarizers, TAC (Triacetate Cellulose Ester) film and PVA (Polyvinyl Alcohol) film are the main raw materials, and the cost accounts for 50% and 12%, respectively.

1.2 Optical film is a key component of LCD backlight module

LCD is the product type with the most mature technology, the most support manufacturers, and the most widely used in the field of new flat panel display devices. LCD (Liquid Crystal Display, liquid crystal display) is a liquid crystal placed between two parallel glass. There are many small vertical and horizontal wires between the two glass. The rod-shaped crystal molecules can be It is refracted to produce a picture.

The backlight module (BLU) is a key component of the light source provided to the back of the LCD display. The LCD panel itself does not have light-emitting characteristics, therefore, a light-emitting source must be added to the LCD panel to achieve the display effect. LCD backlight modules are mainly composed of backlight sources, optical films, adhesive products, insulating products, plastic frames, etc. Among them, various optical films are the key components of the backlight module. According to their functions, they can be mainly divided into reflectors, diffusers, prism films, light guide plates, lamp reflectors, etc. From the perspective of technological development, LCD development trends include large screens, high definition, the use of LED backlights instead of CCFL backlights, ultra-thin, wide color gamut, support for 3D display, and intelligence, etc., but these development trends will not Change the basic backlight display principle and structure of LCD. Therefore, LCD takes advantage of a series of outstanding advantages such as small size, light weight, no radiation, no dazzling, good anti-interference, good shock resistance, large effective display area, etc., and it is rapidly gaining the status of mainstream display technology worldwide. .

1.3 The economical cutting number of TFT-LCD LCD panels should reach more than 6

Liquid crystal display (LCD) technology is a cross-century flat panel display technology. Its emergence and development have revolutionized display technology.

According to the size of the glass substrate, the flat panel display production line can be divided into different generations. For example, the 2.5-generation line commonly used for small and medium-sized applications, the size of the glass substrate is 400mm *500mm, 410mm*520mm, etc., and the 8-generation line for large-size TV panel applications is 2200mm*2600mm. The generation of flat panel displays is only related to the size. The larger the size and the higher the production value of large-size application products, the higher the utilization efficiency; but the advanced nature of the production process and the product is not necessarily related to the generation.

Considering the product yield and the utilization efficiency of glass substrates, the economical cutting number of glass panels needs to reach 6 or more. For example, take the 8th generation line glass substrate, the size is 2160*2460mm2, when cutting 37-inch LCD-TV, 12 pieces can be cut, and the utilization rate is 85%; cutting 46-inch LCD-TV can only cut 8 pieces, using The rate is only 88%; while the production of 57 inches only produces 3 pieces, and the capacity utilization rate is 51%; it can produce 65 inches and 2 pieces, and the capacity utilization rate is only 44%. On the whole, the 8-generation line produces 37, 46, and 52-inch capacity with higher utilization rates, while other sizes have lower utilization rates. Therefore, the larger the size of the application product, the higher the generation of the production line required to achieve economic cutting. This is also the reason why the new production lines to meet the LCD TV market in recent years are mainly concentrated in the 8th generation.

2. TFT-LCD Industry Chain

The TFT-LCD industry is a capital-intensive, technology-intensive, and industrial chain-aggregated industry. Its main characteristics are as follows: First, the speed of industrial line construction, capacity growth, performance improvement, and cost reduction is extremely fast, and product competition is extremely fierce; second, the industry has a high barrier to entry, and it is more difficult to exit once you enter. ; Third, the product application range is wide, the market prospect is broad, the market capacity is huge, and the technology application is relatively mature.

There is a well-known theory in the TFT-LCD industry called the smile curve. The middle part of the smile curve is panel manufacturing; the left is upstream material supply, which belongs to global competition; the right is product application and marketing, mainly local competition. The two ends of the smiling curve are facing upwards. In the industrial chain, the high value-added part is reflected in the two ends, that is, material supply and sales, and the gross profit rate can reach more than 50%. Manufacturing in the intermediate link has the lowest added value, with a gross profit margin of -25~+30%, the lowest added value obtained, and the industry's cyclical fluctuations are large. Therefore, in terms of the profitability of the TFT-LCD industry chain, upstream material companies such as glass substrates, liquid crystals, and backlight modules have significant high-value-added advantages.

Due to the high technical threshold and strong profitability, the key technologies and markets of upstream materials are basically in the hands of a few global companies. For example, glass substrates are monopolized by Corning, Japan, Asahi Glass, and Electric Glass, and liquid crystals are monopolized by Merck and Chisso of Japan. , The polarizer market is monopolized by Nitto Denko, LG Chem and Sumitomo Chemical.

From the perspective of industry development prospects, LCD TVs will continue to dominate. With the gradual discontinuation of the two types of TVs, CRT and PDP, TV manufacturers will focus more on LCD TVs that are more cost-competitive. As an emerging TV flat-panel display technology, OLED, in addition to the scale of investment that cannot be compared with TFT-LCD, has an uncertain technology route for large-size OLEDs, poor yield rates, and higher prices, all of which have become the biggest problems restricting its development.

Large-size TFT-LCD panels are mainly used in four areas, namely LCD screens, LCD TVs, laptop telegraphs, and tablet computers. From the perspective of industry development trends, in the future, the proportion of OLEDs in small sizes will gradually increase while LCDs will decrease. In large sizes, LCDs will still be dominated. According to the quarterly shipment data of large-size TFT-LCD panels calculated by IDC, the shipment volume of TFT-LCD panels from the first quarter of 2015 to the first quarter of 2017 showed the characteristics of volatility. Among them, the global shipments in the first quarter of 2017 The volume is 190 million square meters, and the proportions used in LCD screens, LCD TVs, notebook telegraphs, and tablet computers are 18.03%, 31.69%, 23.30%, and 26.98%, respectively.

From the perspective of manufacturers, BOE is the world's largest manufacturer of large-size TFT-LCDs. At present, BOE has built the world's first 10.5-generation TFT production line, which is currently the world's highest-generation TFT production line and the world's largest high-tech electronic plant project. It plans to realize the first batch of products to be lit and put into production in 2018. In 2016, the world's top five large-size TFT-LCD manufacturers accounted for 20.5% of BOE, 20.2% of LG, 15.6% of Innolux, 14.3% of AUO and 11.6% of Samsung.

3. The rapid development of the panel industry drives the growth of demand for optical films

3.1 The global supply of polarizers is concentrated in the United States, Japan and South Korea, and there is plenty of room for import substitution

The imaging of the liquid crystal display must rely on polarized light, and the LCD liquid crystal display module must contain two polarizers. In the liquid crystal display module, there are two polarizers attached to both sides of the glass substrate. The lower polarizer is used to convert the light beam generated by the backlight into polarized light, and the upper polarizer is used to analyze the polarized light that is electrically modulated by the liquid crystal. Contrast between light and dark to produce a display picture. Without any polarizer, the LCD module cannot display images.

The polarizer is composed of a multilayer film, and its raw material cost accounts for 80% of the total production cost. The raw materials are mainly composed of TAC film, PVA film, pressure sensitive adhesive, protective film and release film. TAC accounts for about 50% of the cost, PVA accounts for 12%, glue 5-10%, protective film, release film 15%, Chemical materials account for 5%, and other costs account for 10%. The core technology of the polarizer is the preparation of TAC (Triacetyl Cellulose Ester) film and PVA (Polyvinyl Alcohol) film. The technology and market are almost completely controlled by Japan. Among the various film layers required for the production of polarizers, TAC film and PVA film are the most important film layers, accounting for more than 60% of the raw material cost of the polarizer. Japan's Fuji occupies more than 80% of the TAC film market, and KONICA occupies about 20% of the market. Kuarary occupies 65% of the PVA film market. The gross profit margin of the polarizer factory is also subject to the monopoly of upstream film materials, which is about 20-30% lower than that of liquid crystal and glass substrates. However, with the breakthrough of Taiwanese manufacturers in TAC technology, the cost here is expected to decrease in the future.

Polarizer production technology is divided by the stretching process of PVA film, which can be divided into two categories: dry method and wet method. The dry stretching process means that the PVA film is stretched to a certain ratio in an inert gas environment under certain temperature and humidity conditions, and then the preparation process of dyeing, fixing, compounding, and drying is carried out; the wet stretching process It refers to the production method in which the PVA film is dyed first, and then stretched, fixed, compounded, and dried in the solution. At present, the global polarizer manufacturers mainly use wet stretching technology.

According to different polarizing components, polarizers are divided into two categories: iodine series and dye series. Iodine-based polarizers use iodine molecules as the polarizing component. This type of polarizer has good polarization and high transmittance, but iodine molecules are volatile in high temperature environments, which makes iodine-based polarizers insufficient in durability; Dye-based polarizers use bidirectional absorption dyes as the polarizing component of the polarizer, which can better solve the durability problem, but to achieve a certain degree of polarization, a higher dye concentration is required, which reduces the transmission of the dye-based polarizer. Rate. At present, polarizers are mainly based on iodine-based polarizers.

The basic performance indicators of the polarizer mainly include: optical performance, durability performance, bonding characteristics, appearance performance and other special properties. Optical performance includes three main performance indicators: degree of polarization, light transmittance and color tone. Others include UV protection and transmissivity, total reflectance and diffuse reflectance indicators of semi-transmissive polarizer and semi-transmissive film. Durability technical indicators include four items: high temperature resistance, damp and heat resistance, low temperature resistance, and cold and heat shock resistance. The most important of which is the level of damp and heat resistance performance indicators. The technical indicators of bonding characteristics mainly refer to the characteristics of the polarizer pressure-sensitive adhesive, generally including: the peeling force between the pressure-sensitive adhesive and the glass substrate, the pressure-sensitive adhesive and the peeling