MS Makes Ultra-Narrow Bezels A Reality
Key Client/Industry/Application Info
Leading TV Brand
- Create world’s first ultra-narrow bezel TVs - Save costs and space within TV sets by finding an alternative to PMMA
- High water absorption of standard PMMA demands a minimum width in screen bezel - Finding the right polymer that balances high optical properties and low water absorption
CHIMEI developed a new MS resin and light guide plate that balance the high optical properties of PMMA and the low water absorption of PS
By switching from PMMA to MS, our customer could cut TV bezel widths by two-thirds
A leading TV-maker wanted to achieve a world-first: ultra-narrow TV bezels. However, the mission had hit a roadblock: the mura effect. A key material within a TV screen’s light guide plate, polymethyl methacrylate (PMMA) expands when it absorbs water vapor. If the TV bezel is too thin, there is no room for that expansion and the PMMA bends against the side casing. This creates the mura effect, blurring the screen. The obvious solution was to replace the PMMA, but there was no alternative readily available at that time. Therefore, the leading TV brand tasked us at CHIMEI, their biggest supplier, with finding a suitable alternative.
We quickly rejected polystyrene (PS) as an alternative due to its low optical properties, despite its low water absorption. Instead, we decided to see what we could achieve with MS, a transparent copolymerization of methyl methacrylate (MMA, also used in PMMA) and styrene monomer (SM, also used in PS). In short, we wanted to find a middle ground between the optical properties of PMMA and the low water absorption of PS. Over the next year, we experimented with different ratios of MMA and SM, made equipment modifications, and optimized our process conditions. After multiple rounds of sample testing conducted directly with our customer, we created a new grade of MS resin and a new MS light guide plate (MS LGP) that could deliver the performance required: MS PM-500G and MS PM-500X.
With CHIMEI’s optical MS grade, the leading TV-maker could trim its bezel width by two-thirds, to produce the world’s first ultra-narrow bezel TVs. Soon, other leading LCD TV and LCD panel-makers from Mainland China, Japan, and Taiwan also sought out our industry-leading MS and MS-based light guide plates, to create next-generation TV technologies.
If customers change from PMMA to MS, they can save two-thirds of the space at the edge of the screen. Then it’s easy to design for ultra-narrow bezels.
Project Manager at CHIMEIs
Water Absorbency in PMMA vs MS
PMMA is a key material inside most TV screens’ light guide plates, but has relatively high water absorbency at 0.45%. PMMA expands when it absorbs water vapor, meaning the TV screen will become blurry if the PMMA hits and bends against the TV’s side casing. CHIMEI’s optical MS has much lower water absorbency at 0.15%, meaning it expands much less than PMMA. By using our MS, TV-makers can cut the extra space at the side of the TV (which is covered by the bezel) by two-thirds.
CHIMEI is a Taiwan-based performance materials company that designs and manufactures advanced polymer materials, synthetic rubbers, and specialty chemicals.