The "dyes/coloring materials" used in China's LCD manufacturing industry are primarily not traditional textile dyes, but highly specialized optoelectronic functional dyes and pigment systems, mainly used for color display, polarization control, and optical adjustment. They can be categorized by application stage as follows:
I. Color Filter (CF) Dyes/Pigments (Most Core)
This is the category with the largest usage and highest technological barriers in LCD panels.
1️⃣ RGB Organic Pigments (Mainstream)
Currently, major domestic LCD manufacturers (BOE, TCL CSOT, HKC, Tianma, etc.) primarily use high-light-durability organic pigment systems, rather than ordinary dyes.
Red (R)
Azo Pigments (Modified)
Quinacridones (High-end)
Green (G)
Cu-phthalocyanine Green
Blue (B)
Cu-phthalocyanine Blue
Features:
High heat resistance (≥230–260°C)
High lightfastness and chemical resistance
Low metal ion release (avoids electrode corrosion)
Domestic Supplier Trends:
Localization rate is increasing, but some high-end pigments still rely on imports (Japan, South Korea)
2️⃣ Dye-based Color Filter Materials (Gradually Decreasing)
Early LCDs used solvent-based dyes, but their use has significantly decreased:
Azo dyes
Anthraquinone dyes
Pyrazolone dyes
❌ Disadvantages:
Insufficient lightfastness
Rapid color decay
Unsuitable for high brightness/long lifespan displays
Currently mainly used in low-end or special display products.
II. Polarizer Dyes
Polarizers are a key component of LCDs. The core dyes are:
3️⃣ Iodine-based polarizing dyes (most traditional)
Iodine (I₂)/iodide composite system
Adsorbed onto stretched PVA film
Features:
High maturity
Low cost
Still the mainstream solution
Applications:
Mobile phones, TVs, LCD monitors
4️⃣ Dichroic organic dyes (high-end alternative)
Used to replace some iodine-based systems:
Azo dichroic dyes
Anthraquinone dichroic dyes
Thiophene, styrene derivatives
Advantages:
Higher heat resistance
More moisture resistance
More suitable for automotive and outdoor displays
Current status:
Domestic production is still mainly based on imports or joint ventures
Domestic production is accelerating
III. Functional Dyes for Liquid Crystal Alignment Films & Optical Compensation Films (Niche but crucial)
5️⃣ Photosensitive/Photoalignment Dyes
Used in photo-alignment technology:
Azobenzene photoisomer dyes
Cinnamic acid derivatives
Applications:
High-end IPS, VA panels
High-resolution displays
6️⃣ Optical Compensation/Color Toning Dyes
Used to improve:
Color temperature
Contrast ratio
Viewing angle compensation
Typically:
Specialty organic dyes
Small amounts of metal complex dyes
IV. General Characteristics of Dyes in the Domestic LCD Screen Industry
✅ Not a traditional dye industry
✅ Leaning towards "electronic chemicals / optoelectronic functional materials"
✅ Emphasizing purity, stability, and reliability, rather than color depth
Metal ions: ppm or even ppb level
Thermal stability: ≥250°C
UV resistance: Long lifespan
Batch stability: Extremely high