Those who are familiar withTFT LCDtouch display screens must have heard ofIn-Cell/ On-Cell/ OGScapacitive touch technology. In many industry fields,LCDcapacitive touch screens are widely used. However, the touch display screens (capacitive or resistive) currently used in the market are mostly separated touch display screens, meaning the touch screen andLCDdisplay are produced separately and then assembled together. In this era of pursuing intelligent technology integration, suchLCDtouch screen technology can no longer meet people’s usage needs.
1.1LCDTouch Screen Structure
The basic structure of a standardLCDdisplay touch screen can be divided into three layers: protective layer, touch layer, and display layer. Generally, after the protective glass, touch layer, and display panel are bonded together, there will be an air gap because mostLCDtouch screens use frame bonding technology. There will be an air layer between the touch screen andLCDdisplay. However, full bonding technology removes the air layer, thus reducing the screen thickness. This significantly reduces screen reflection, making the screen thinner and more transparent, and it appears blacker when turned off, remaining clear even in bright light.
1.2LCDTouch Screen Full Bonding&Frame Bonding Technology
Frame bonding: InLCDtouch screens, most of the touch screens we frequently encounter are frame bonded touch screens. Frame bonding, also known as frame adhesive bonding, uses double-sided adhesive to fix the touch screen around the display panel, which is simple to operate and cost-effective, with a high yield. However, there will be air-filled gaps between the display panel and the touch screen, making the screen relatively thicker than full bonding, and due to the presence of the air layer, the screen is prone to dust intrusion, causing theLCDdisplay effect to be less than ideal.
Full bonding:LCDtouch screen full bonding technology is the trend of the future. Full bonding uses glue or optical glue to completely bond the panel and touch screen together without gaps, eliminating the air layer between the display layer and touch layer, preventing dust intrusion and reducing reflection between the display panel and glass. This bonding technology makes the entireLCDdisplay screen lighter and thinner, making the display appear more transparent and improving the display effect. However, full bonding technology is difficult, with a low yield rate, making it more expensive, so only a small number of strict requirements will choose full bondingLCDtouch screens. However, from the current development trend of smart display devices, full bondingLCDtouch screens will undoubtedly become mainstream. What technologies are available to achieve full bondingLCDtouch screens?
1.3Capacitive ScreenOGS/ On-Cell/ In-CellTouch Technologies
OGStechnology:OGS(one glass solution) is currently the main solution used in full bondingLCDcapacitive touch screens. It integrates the touch layer and protective layer glass together, coating the inner side of the protective glass with anITO(indium tin oxide) conductive layer, directly coating and photolithographing on the protective glass, thus saving a piece of glass and one bonding process, makingLCDtouch screens lighter and thinner while reducing costs. However, sinceOGSprotective glass and touch screen are integrated, it usually requires prior strengthening, then coating, etching, and finally cutting. Cutting on strengthened glass is very troublesome, and some capillary cracks may form on the glass edges, which can reduce the strength of the glass.
In-celltechnology:In-cell technology embeds the touch panel function into the liquid crystal pixels, meaning the touch sensor function is embedded within the display screen. In-cell technology places theITOtouch film beneath the upper glass substrate of the display panel, integrating it with the liquid crystal layer. The innovation of in-cell touch panels lies in loading circuits onto the liquid crystal, enabling the liquid crystal screen to possess the perception and touch input capabilities of traditional touch screens. In-cell touch panels not only have higher accuracy but also eliminate the need for a touch panel, thus making the entire touch screen lighter and thinner. Traditional touch screens are relatively difficult to read the display content under sunlight, but now, as there is no touch panel, there is naturally no parallax, improving readability.
On-Celltechnology:refers to embedding the touch screen between the color filter substrate and the polarizer of the display screen, meaning a touch sensor is matched with the liquid crystal panel. Its technical difficulty is somewhat simpler thanIn-cell, and it is currently widely used in SamsungAmoledpanel products, although it has not yet overcome issues such as thinness and color uniformity during touch.
2 CTPThree Structures
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https://mp.weixin.qq.com/s/60cg3t1KfFVd7AUaIvRVhw
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https://mp.weixin.qq.com/s/mKkOJ98IkyHfCpjpOLC33w