Electronic Design
Enhance LED Flash Photography Performance in Camera Phones

Enhance LED Flash Photography Performance in Camera Phones

New Polyacene Supercapacitors retain highest capacitance density and low ESR, while realizing a lower profile.

Today’s consumer depends on a mobile phone for far more than communication. Fact is, the digital images captured with camera phones are as ubiquitous as the phones themselves. Photos are seamlessly shot and uploaded to social networking Web sites and an abundance of other Internet forums, where they are shared, stored and printed. The public’s growing demand for quality camera phone images has resulted in the production of devices that can compete even with stand-alone digital cameras.

For improved picture quality, developers often equip camera phones with LEDs as a low profile auxiliary light. Low lights for photographic use, however, fail to provide the necessary luminance for bright and clear images. A built-in flash is required to enhance the brightness of camera phone LEDs. Low profile capacitors for LED flash pulse current discharge applications, or supercapacitors, are recommended to enable the supply of high currents over a shorter period of time.

One supercap, the Polyacenic Supercapacitor, is an especially ideal solution for LED flash pulse current discharge applications. It features some of the highest capacitance densities and low ESR within a low-profile package.

Polyacenic Supercapacitors – Constructed for Higher Capacitance

While most supercaps only take ions to the surface of the electrode, the Polyacenic Supercapacitor features a honeycomb-like structure that allows ions to penetrate the electrode for greater capacitance. The unique construction of the Polyacenic Supercapacitor results in capacitance levels approximately 1.4 times higher than standard supercaps (see fig. 1). Polyacenic Supercapacitors consist of plus and minus ions in electrolyte which are doped into polyacen electrodes to generate high energy densities. They are encased in aluminum with an electric conductive polyacenic polymer for the electrode. Polyacen is a type of semi conductive polymer made by introducing phenol resin to thermal condensation.

The encapsulating technology of Polyacenic Supercapacitors makes reflow soldering with an eco-friendly Pb-free solder possible. Polyacenic Supercapacitors are therefore environmentally friendly, as well as RoHS compliant.

Alternative to Secondary Batteries and Traditional Capacitors

Polyacenic Supercapacitors are excellent alternatives to secondary batteries and aluminum capacitors. They last longer and provide quicker charge and discharge capabilities than re-chargeable batteries. When compared with general secondary batteries, Polyacenic Supercapacitors provide 10 times higher input power density and can quick charge for those devices needing instant charging. In fact, handling high currents, as well as frequent charges and discharges, they effectively reduce the load and extend the life of the primary battery (see fig. 2).

In addition, this form of Supercapacitor requires only a simple peripheral circuit rather than the complex circuitry required for a second battery. The result is improved reliability and a reduction in material and production costs.

Polyacenic Supercapacitors provide increased energy capacity over traditional electrolytic capacitors of the same size. The polycen electrode offers exceptional heat-, chemical- and oxidation-resistance.

Coin, Cylinder and Thin-Film Type Polyacenic Supercapacitors

Polyacenic Supercapacitors are available in coin, cylinder and thin-film types (see fig. 3). All can be reflow soldered due to the excellent heat resistance of Polyacenic electrodes and higher energy density.

Coin Type Polyacenic Supercapacitors achieve higher density than electric double-layer capacitors. And, unlike secondary batteries, they do not have a charging voltage threshold at the redox potential.

Cylinder Type Polyacenic Supercapacitors offer high capacitance with low ESR. The electrolytic ions are easily doped and un-doped to the polyacene. Available in 3 volt versions, they exceed the industry standard of 2.7V maximum voltage. When grouped in a device, these supercaps therefore require less space and save costs.

Thin-Film Polyacenic Supercapacitors are designed for assistance to secondary batteries in handsets or for backing up the power supply of Solid State Drives (SSDs).

Applications

Polyacenic Supercapacitors fit today’s compact and thin device niche well. Along with LED applications in camera phones, Polyacenic Supercapacitors are recommended for smartphones, digital still cameras and digital camcorders, as well as portable printers and scanners. Polyacenic Supercapacitors can be used for peak power assistance, as a RTC back-up power source or as the main power source for small devices.


About The Author

ATSUYA SATO | Taiyo Yuden Co., Ltd.

ATSUYA SATO is an engineer in Taiyo Yuden’s ECD (Electric Chemical Device) Development Department. He has worked in Taiyo Yuden Co., Ltd. Energy Devices (formerly Shoei Electronics Co., Ltd.) Osaka, Japan office, where he oversaw business with European, Chinese and South Korean mobile phone manufacturers.

After company restructuring in 2010, Mr. Sato moved to Taiyo Yuden Co., Ltd. Electric Chemical Device Development Department, and currently supports sales offices in Europe, United Sates and South Korea.

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