Optical Films for Liquid Crystal Displays
Single Consumption Management Requirements
Some say that the distance between people and the information world is just the thickness of a display screen, but in reality, various “films” are sandwiched in between. Today, I will combine the requirements for single consumption management in processing trade to show you the various large “films” found in liquid crystal displays.
1
Introduction to Optical Films
A liquid crystal display (LCD) is a common finished product in processing trade. The optical films in the backlight module are key components of the LCD panel, serving to provide sufficient brightness and evenly distributed light so that the screen can display images normally.
Light Guide Film
To convert the line or point light source of the backlight into a surface light source, a light guide film is required. Light guide films are generally made of high-transparency acrylic plastic, with a smooth and flat surface, and a white dot pattern printed on the bottom. By controlling the dot density, the amount of emitted light can be regulated.
Reflective Film
Most of the light coming out of the light guide film goes upwards, but some will go downwards. To fully utilize the downward light, reflective films are needed to direct the light upwards. The most common reflective film is made of PET as the substrate, printed or laminated with a white reflective layer, with barium sulfate as the main raw material, or a silver reflective layer coated on PET.
Diffusion Film
The upward light from the light guide film and reflective film enters the diffusion film. The main function of the diffusion film is to correct the side light of the backlight module into a uniform surface light source, achieving optical diffusion and uniform light emission. There are upper and lower diffusion films.
Brightness Enhancement Film
Also known as prism film. The light that exits the diffusion film enters the brightness enhancement film. The thickness of the brightness enhancement film ranges from 50 to 300 micrometers, with a uniformly and neatly covered prism structure on the surface. The brightness enhancement film is used to improve the distribution of light at the viewing angle without increasing the total emitted luminous flux.
Reflective Polarizing Film
The light emitted from the backlight source that hits the polarizing film of the LCD can lose energy as heat. By using reflective polarizing films, this type of energy loss can be avoided. Reflective polarizing films can also improve the overall photoelectric conversion efficiency and energy efficiency of the LCD module.
2
Precautions for Single Consumption Declaration
In conjunction with the actual customs supervision of processing trade, I will emphasize several aspects that need attention regarding the single consumption declaration of optical films for liquid crystal displays.
1. Single Consumption Standards
The “Announcement on the Release of 58 Processing Trade Single Consumption Standards” (General Administration of Customs National Development and Reform Commission Announcement No. 37 of 2015) released the “Processing Trade Single Consumption Standards for Polarizers Over 26 Inches” (Standard No. HDB/YD028-2015). In the “Announcement on the Release of 57 Processing Trade Single Consumption Standards” (General Administration of Customs, National Development and Reform Commission Announcement No. 43 of 2016), the “Processing Trade Single Consumption Standards for Reflective Films for LCD Backlight Modules” (Standard No. HDB/YD038-2016) was released. During production, enterprises in the processing trade of LCDs must ensure that the declared single consumption of polarizers and reflective films does not exceed the upper limit of the corresponding national standards. For other products in the backlight module, enterprises should declare single consumption to customs based on their actual production.
2. Accurate Declaration of Single Consumption Composition
Enterprises should accurately declare the name, model, function, purpose, and brand of the optical films in accordance with the types of optical films and actual production during the record-keeping and actual import/export processes.
For semi-finished LCDs, the composition of the single consumption of their optical films should be accurately declared. For example, if the product does not include a polarizer, it should be noted in the name as “not including polarizer”. If it includes a polarizer, the quantity, specifications, and source of the polarizer should be accurately declared during the single consumption declaration process.
3. Accurate Declaration of Measurement Units
In addition to the standardized declaration elements required by the customs declaration form, processing trade enterprises should ensure clarity in the measurement units for rolls and various types of optical films that have been cut, aligning with actual production.
Generally, uncut optical film rolls can be declared by “meters” with the corresponding width and thickness noted. Cut optical films should correspond to different sizes of LCDs, distinguishing materials, specifications, sizes, purposes, and thicknesses, and declared by “pieces”, “sheets”, “units”, etc. Enterprises engaged in cutting processing should accurately declare the single consumption generated during the cutting process and ensure the correspondence of different measurement units before and after cutting to ensure accuracy.
4. Utilize the “Finished Product Single Consumption Version” Effectively
Many LCD manufacturing enterprises have hundreds of finished products, and traditional paper and electronic manuals can no longer meet their record-keeping needs, leading to risks of misreporting names and inaccuracies in single consumption declarations.
The reform of the processing trade supervision model based on enterprises is an important measure for customs to deepen the reform of processing trade supervision, promote innovation and development in processing trade, enhance customs supervision and service levels, and support the development of processing trade enterprises.
Processing trade enterprises for backlight module products can adopt an “enterprise-based” electronic ledger according to their own situation, implement material number-level management, accurately declare various data to customs by adjusting the single consumption version, and adopt an annual declaration method to fully enjoy the conveniences brought by customs optimization of supervision processes, thereby reducing operating costs.
Reprint must indicate the source “12360 Customs Hotline”
Note: Some images are sourced from the internet
Provided by: Huangpu Customs
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