Page 42 - 2020 Interconnect Innovations eBook

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Finally, the mating connection must be sufficiently rugged and robust to withstand the rigors of assembly and usage without accidental unmating. An acceptable level of quality is essential to meeting end users’ expectations in terms of production processes.
Connector Technologies for Portable Devices
The small form factor of wearables and portable devices impacts the types of connectors that can be used. Traditionally, there are four types of connectors that can be used to connect boards via FPC or FFC. While the first two connectors listed below are not typically used in portable devices, they led to the development of the connectors that are used. Each connector type has advantages and disadvantages:
Low-Insertion-Force (LIF) Connectors employ an older technology that features a one-piece design with no moving parts. The flex is simply inserted into the connector, offering very easy assembly with horizontal mating. However, there is no mechanism to hold the flex in place, other than the friction of the contacts on the flex, so LIFs provide little to no retention force. They are also quite limited in size and pitch offerings.
Slide-Lock Zero-Insertion-Force (ZIF) Connectors also use an older technology that requires no insertion force to push the flex into an open actuator. However, they must then be manually activated and closed to provide the retention force. Slide-lock ZIFs have a complicated assembly process and are susceptible to user error and damage when the actuator is touched during assembly. They also provide horizontal mating and are limited in size and pitch.
Flip-Lock ZIF connectors evolved from previous designs and are widely used in mobile devices. The flex is inserted into the connector with one hand, and the other hand is used to flip the actuator to close and lock it. They come in both front flip-lock and backflip-lock styles and enable easier assembly than slide-lock ZIFs do, but users still have to touch the actuator, which has the potential to cause damage. Flip-lock ZIFs also offer provide horizontal mating but with better retention forces and more options in terms of size and pitch than LIF and slide-lock ZIF connector. One of their biggest advantages is that they’re optimized for mobile electronics. Their biggest drawback is that they require two-handed operation.
Mezzanine Board-to-Board (BTB) Connectors are two-piece connector systems with an easy, one-handed mating mechanism that allows users to guide the plug into the receptacle and simply press down. BTB connectors offer easy assembly, better retention forces, and numerous options in terms of size and pitch. They only support vertical mating, but they are a very popular choice in mobile devices when vertical access is available.
Connector Technology Evolves to Satisfy Portable Device Demands
Flip-lock ZIF and BTB connectors have become the default connectors for most portable devices and other small- form-factor designs. However, Hirose Electric Co., Ltd. has developed new technologies for ZIF-style flex connectors that support flex insertion without the need to engage an actuator and while still maintaining retention force on the flex. Hirose’s new One Action connectors simplify the mating process by keeping the primary benefits of the older LIF and existing BTB connectors — the easy, one-handed mating action — as well as the top benefits of the actuator- style ZIF connectors, including improved retention force and the ability to unmate the connector using the actuator.