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From smartphones and tablets to TVs and computers, thin displays have become integral to our modern lives.
The display technology has undergone an impressive evolution.
ACF has been fundamental to advancing display technologies, from LCD to OLED and flexible OLED. Let’s explore how display technology has evolved and examine ACF’s vital contribution to this journey.
The LCD story began in the 1960s with a breakthrough discovery: liquid crystals could be used to create visual displays.
This technology found its first commercial applications in calculators and wristwatches during the 1970s, before expanding to larger formats like laptops, TVs, and monitors in the 1990s.
In LCD’s evolution, the push toward thinner profiles and higher resolutions was paramount.
ACF proved instrumental in this development by providing reliable circuit connections.
The technology delivers not only ultra-thin connections but also ensures robust bonding, exceptional reliability, and effective electrical isolation between adjacent circuits.
Its versatility extends to various substrates, enabling connections for Tape Carrier Package (TCP) and Chip on Film (COF) package signal outputs to displays, while also supporting Chip on Glass (COG) driver IC implementation.
The adoption of ACF has enabled higher resolutions through the miniaturization of circuits and contributed to thinner and lighter devices through the miniaturization of driver ICs.
LCD technology has developed rapidly since the discovery of the principles behind the use of liquid crystals for visual display. but it may not have been possible to achieve the modern thin and high-resolution displays without the evolution of ACF technology.
As LCD technology matured, OLED emerged as the next generation of display technology.
After the Eastman Kodak Company announced the fundamental principles behind OLED in 1987, elements that emit their own light were used to achieve display technology that featured higher contrast than conventional LCD, wide viewing angles, thinness, and lightweight.
However, initial adoption was hampered by manufacturing costs and technical hurdles.
Several factors contributed to OLED’s initially slow market penetration: prohibitive production costs, limited lifespan of blue organic electroluminescent elements, and image retention issues with static content.
Additionally, the complexity of OLED manufacturing processes and low yield rates presented significant challenges for mass production.
OLED technology made its breakthrough in the late 2000s, first appearing in small displays for smartphones and digital cameras as manufacturers overcame initial technical hurdles.
As the technology’s advantages became increasingly apparent, OLED displays expanded into large-screen TVs and flexible displays. Throughout this evolution, ACF technology adapted and advanced to accommodate OLED’s unique electrical properties and circuit designs.
The advent of flexible OLED displays, utilizing polyimide substrates, marked a breakthrough in creating durable, highly flexible foldable displays.
While this technology opened new possibilities for flexible displays and wearable devices, it presented a significant challenge: maintaining reliable electrical connectivity with flexible substrates.
To address this challenge, innovative mounting technologies emerged, including FOP (mounting flexible FPC directly On Plastic) and COP (mounting hard IC On plastic substrate).
These solutions rely heavily on ACF technology to create secure connections between flexible plastic substrates and rigid driver ICs. ArrayFIX, represents a significant advance in this field. This particle-arrayed ACF technology delivers exceptional connection reliability in an extremely small area while maintaining electrical isolation between adjacent electrodes. By ensuring precise, dependable connections even in challenging environments, ArrayFIX has dramatically enhanced flexible OLED performance.
ACF technology stands as a cornerstone in advancing high-definition display technologies across LCD, OLED, and flexible OLED platforms. Its distinctive capabilities include ultra-fine pitch connections at pitches below 100 micrometers and remarkable adaptability to various electrode materials.
This versatility in accommodating different conducting materials, from ITO electrodes to metal electrode, has been instrumental in pushing the boundaries of display resolution and performance across all display technologies.
The innovative ArrayFIX technology showcases the continued evolution of ACF. Its precise particle alignment capability enables optimized connections for specific electrode materials and pitches, driving further improvements in display performance. The technology’s success with both FOP and COP applications has made it essential for the advancement of flexible OLED technology.
Throughout the display industry’s evolution from LCD to OLED and flexible OLED, ACF has been a crucial enabler of technological progress.
Its contributions have been fundamental to achieving higher resolution displays, enhanced designs, and reliable connectivity solutions.
Looking ahead, it remains committed to advancing ACF technology to support emerging display technologies such as microLED and silicon OLED, continuing our mission to enhance products that enrich our daily lives.
Shenzhen olian,ACF COF COG COP FOG FOP FOF FOB FOF TFOG TFOF OLB TAB bonding machines manufacturer.
What is anisotropic conductive film (ACF)?Anisotropic Conductive Film (ACF) serves as an adhesive for securing and electrically connecting electronic components, like integrated circuits (ICs), to circuit boards.
Originally introduced in 1977, ACF is now a staple in nearly all digital devices that employ flat panel displays—think smartphones, tablets, and high-definition TVs.
ACFs are typically used to connect the display panel to the flexible substrate that transmits signals to the panel or to the IC. Common applications of ACF include: COG (Chip-on-Glass), which connects the IC and glass substrate FOG (Flex-on-Glass), which connects the flexible substrate and glass substrate FOB (Flex-on-Board), which connects the flexible substrate and rigid substrate Other applications of ACF extend to smart cards, camera modules for CCDs (charge-coupled devices), and CMOSs (complementary metal oxide semiconductors). Shenzhen olian design and manufactur all the COG,COF,COP,FOG,FOB,FOP,FOF,TFOG,TFOF ACF bonding machines.
Anisotropic Conductive Film serves three primary functions simultaneously: adhesion, electrical conduction, and insulation. This unique capability allows manufacturers to connect a large number of pads at once.
Unlike traditional soldering, ACF enables fine pitch connections. The film is composed of conductive particles dispersed in a thermoset resin. A typical particle features a polymer core coated with nickel or gold, covered by an insulating layer.
When heat and pressure are applied, the opposing pads capture these particles. This process breaks the insulating coating to establish a vertical electrical connection. Particles trapped between pads remain insulated, preventing short circuits.
Key Technical Specifications:
The bonding process is precise and efficient. Shenzhen Olian recommends following these steps for optimal results:
ACFs are sold in reels, as shown in the photo below. They come in a wide range of film thicknesses. From 10 to 45μm, widths from 0.5 to 20mm, and lengths from 10 to 300m.
The figure below illustrates two types of ACFs: a three-layer type, where ACF is sandwiched between a protective film and a release film.
And a two-layer type where only the release film is used. Each type offers different benefits. The three-layer type reduces the risk of dust contamination, while the two-layer type eliminates the need to remove the protective film during bonding.
As technology advances each year, circuit boards are becoming increasingly fine pitch, the area of connecting pads is shrinking, and the spacing between them is narrowing.
While reflow soldering and connector components are traditionally used for bonding electronic components such as ICs to circuit boards, ACFs provide a solution to these trends.
However, a disadvantage of ACF is that it is challenging to bond components of different shapes simultaneously, which is common in reflow soldering.
Also, since ACF is an adhesive, it cannot be freely removed and reattached like mechanical connectors.
Why Choose ACF?
Benefits of ACF
Dexerials has been continually enhancing ACF since its introduction in 1977. Initially, the conductive particles used were carbon fiber and solder particles. However, in 1988, Dexerials developed particles plated with nickel and gold.
By the 1990s, Dexerials had successfully developed a technology to coat the surface with insulating material.
As digital devices have evolved towards higher definition, Dexerials has adapted to the trend of fine pitch connections by reducing the particle size from 5μm to 2.8μm.
In 2014, Dexerials developed a technology to uniformly align conductive particles in thermosetting resin.
And in 2016, began marketing the product as “particle-arrayed Anisotropic Conductive Film” (ArrayFIX). This product contributes to the miniaturization, slimming design of digital devices, and higher resolution displays.
When selecting the best ACF, several factors should be considered, including the type of adherend, connection area, distance between pads, height of pads, and heat resistance.
ACF is composed of either epoxy resin or acrylic resin that cures with heat. we recommends acrylic ACF for applications where Flexible Printed Circuits (FPCs) and substrates (PCBs or glass substrates) are to be bonded, and where the design is intended to be reworked after the main bonding. (Please note that Dexerials does not recommend reworking itself. Dexerials advises that rework should only be done after reliability evaluations have been conducted to ensure that there are no issues.) Dexerials does not recommend ACF with epoxy resin if there is a possibility that the customer will rework. The primary reason is that it often damages the substrate to be reworked. This is because cured epoxy resin does not dissolve in solvents, and the process involves scraping off the residue.
Reworking after bonding typically involves heating the bonding area with a heat gun, hot iron, hot plate, etc., and then peeling off the FPC. Afterward, the cured resin residue between the pads on the board should be carefully removed using a solvent such as Methyl Ethyl Ketone (MEK) or N-Methyl-2-pyrrolidone (NMP) and a cotton swab. However, Dexerials does not recommend reusing FPCs because FPCs often curl during the peeling process and cleaning the resin residue between the pads on the FPC side is challenging.
With over 40 years of leadership in ACF technology, Dexerials can provide services including the initial setup, proposing an appropriate ACF, and post-connection analysis and evaluation. If you have any questions about ACF application, please feel free to contact us.
Shenzhen Olian Automatic Equipment Co., Ltd ,established in 2012, is a national high-tech enterprise specializing in the research and development, sales, production, and service of automation equipment for FPD flat panel displays and new flexible screen displays. The company holds multiple invention patents, utility model patents, and software copyrights. At present, the company has a professional R&D team of more than 100 workers, as well as a professional team for production management, quality management, and after-sales service.
Olian’s products include LCM module factories and full process equipment (COG COF COP ,FOG FOB FOF FOP FOC TFOG TFOF bonding, AOI, dispensing, backlighting, soldering), achieving manufacturing of integrated display and touch products. The company’s series of products are widely used in display fields such as mobile phones, electronic tags, tablets, smart wearables, automotive displays, televisions, computers, etc., and provide overall solutions for smart factories.
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