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157:, including LOCA and non-liquid OCA tape, are used in a wide range of electronic equipment, especially those with touch panels. The adhesive bonds the touch panel to the main liquid crystal display, and also bonds any protective cover, such as the lens, to the touch panel. After application, the adhesive is cured onto the device through
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Optical bonding improves optical performance of displays. It eliminates the air gap between the cover glass and LCD, and usually includes an anti-reflective (A/R) coating (as well as anti-smudge and anti-glare treatments on the cover glass). Optical bonding improves the contrast ratio by reducing the
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The curing process and inherent low modulus of silicone LOCA also helps reduce the amount of haze around the edges of large LCD screens. Silicone technology reduces shrinkage on substrates to less than 1% on larger displays, where acrylic technologies tend to be around 3–5%, depending on display
125:) is liquid-based bonding technology used in touch panels and display devices to bind the cover lens, plastic, or other optical materials to the main sensor unit or each other. These adhesives improve optical characteristics and durability. LOCA glue is often hardened using ultraviolet light.
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Besides the optical advantages, bonding a sheet of glass to the LCD also improves display durability. It can resist scratches, condensation, and has an improved operating temperature range. As touchpad devices become ubiquitous in consumer markets, this increased ruggedness becomes even more
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LOCA is generally used in displays and touch panel applications. Application is expected to increase as mobile devices, televisions, tablets, monitors and laptops migrate to touch interfaces. Although there are many varied applications, Henkel divides the applications into three categories:
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from the glass as well as the adhesive can degrade LCD viewability. Reflection is caused by an impedance mismatch between air and the glass. The reflection makes the white brighter, but dilutes black and other colors, which decreases contrast. LOCA suppliers aim to match the
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While traditional adhesive chemistry relies on acrylic-based liquid, new technologies include silicone. Silicone provides new methods for curing the adhesive. The following table illustrates the difference between acrylic and silicone in single and double curing processes.
180:(refractive index approximately 1.5) used in displays to minimize loss. LOCA suppliers such as Momentive Materials and Henkel report an increased contrast of 400% in sunlight through the use of LOCA with anti-reflective glass, vastly improving the viewing experience.
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LOCA follows traditional die-cut film adhesives, also known as optically clear adhesives (OCA tape). LOCA also allows for thinner designs and new technologies, such as the use of silicone, that improve the properties of the final product.
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light (UV), heat, moisture, or a combination, depending on the manufacturer and specifications. Major applications include capacitive touch panels, 3D televisions (3D TV), and glass retarders.
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To bond touch panel sensors that require two layers of ITO (indium-tin-oxide) coated glass. This type of bonding will eventually be replaced by direct bonding.
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amount of reflected light, thus improving viewability. This is especially important in outdoor applications, where direct sunlight can decrease viewability.
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To achieve the highest amount of contrast, such as in an outdoor viewing application, it is necessary to "directly bond" the cover lens to the LCD module.
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Curing equipment usually includes UV curing lamps or spot cure systems. Major suppliers of LOCA generally offer both dispensing and curing equipment.
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To fill the air gap in touch panel sensors that use a cover lens (such as clear plastic PMMA) and the glass touch panel sensor.
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Is contaminant-free, resulting in improved bubble resistance in laminations exposed to high temperature and humidity
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important. Also, reducing light loss due to reflection extends battery life, as the device can use less backlight.
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LOCA has many advantages compared to traditional non-liquid film type adhesives (OCA tape). Specifically, it:
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Dispensing equipment usually includes bubble free dispensers by means of a bottle or cartridge.
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Is completely size-independent, while OCA tape must be pre die-cut
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Primary advantages of LOCA compared to other adhesives are its:
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Facilitates faster development of new products and designs
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Optical bonding for improved LCD outdoor viewability
229:Accommodates thinner and lighter display designs
196:Is suitable for application on uneven surfaces
354:. High Resolution. Veritas et Visus, Aug 2006
211:Ideal for filling gaps because it is a liquid
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106:Learn how and when to remove this message
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214:Does not suffer condensation and fogging
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199:Can be repaired and adjusted once cured
42:Please improve this article by adding
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226:Can be applied by automated process
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249:Three common applications of LOCA
220:Requires less surface preparation
55:"Liquid optically clear adhesive"
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119:Liquid optically-clear adhesive
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135:Adhesion to non-even surfaces
44:secondary or tertiary sources
217:Resists extreme temperatures
254:Touch panel sensor assembly
202:Can be used in large panels
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138:Superior optical properties
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296:Single cure
159:ultraviolet
305:, UV cure
141:Durability
66:newspapers
33:references
403:Adhesives
327:Equipment
313:UV + heat
310:Dual cure
303:Snap cure
291:Silicone
96:July 2020
397:Category
150:Overview
383:Henkel
299:UV only
288:Acrylic
80:scholar
323:size.
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338:Notes
87:JSTOR
73:books
386:2011
178:PMMA
123:LOCA
59:news
373:3M
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