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LEDs

Mon, 02/08/2010 - 7:29am
All indications are that LED backlights will be the preferred light source in mobile applications in 2011, representing a significant growth opportunity for OEMs and the entire backlight and panel supply chain.

Do you see the role of LEDs in wireless products changing as the technology matures?

LEDs


Attention is now shifting away from achieving raw light output that matches incandescent bulbs, to increasing the number of lumens per electrical watt supplied. This evolution and maturing of LED technology may benefit emerging generations of converged wireless devices.

Power LEDs have already been used successfully to implement the camera-flash function in feature-phones, saving the high-voltage circuitry needed for a Xenon bulb and enabling extra features such as a torch. However, designers are always under pressure to deliver more features without sacrificing battery life in wireless-product, with the added desire to improve optical efficiency.

Design limitations arising out of luminance efficacy and LED binning have been overcome to a large extent with developments in LED manufacturing technologies and secondary optics. This has resulted in high-brightness LEDs being used in a host of new applications,such as projectors within cellular phones.

Further improvements in LEDs will be required to help minimize the heat produced by imaginative lighting-based features in next-generation handhelds, to ensure user safety as well as to miniaturize and simplify mechanical design. Early commercial quantum-dot LEDs, announced in 2009, suggest that nanotechnology may provide a solution. As a replacement for the conventional phosphors used to adjust LED emissions, quantum dots – optically tuned nano-particles capable of achieving precise control over emitted wavelengths and directionality – effectively eliminate optical scattering to further improve efficiency, reduce heat generation and enhance color characteristics, all ideal for small wireless products.

Making the most of improvements in LED manufacturing techniques, as well as the new avenues opening up in the nano world, could point the way towards mobile devices delivering enhanced functions, ease of use, and user experiences better than the best we can imagine today.


The mobile sector has been and still is the largest market for LEDs. Market researchers confirm this, although they predict that LED growth in this area will slow. From our point of view, the reason for this is saturation in the keypad and white LCD illumination markets along with pricing developments in recent years. However, other application areas are opening new doors. Flash applications were added to mobile phone cameras several years ago. Since then, LED flash has become the standard, although future camera modules with higher image resolution will require greater luminosity. Additionally, new opto-semiconductor highlight products are moving into the mobile market. At present, these are tiny projectors equipped with LEDs or lasers as light sources, which are becoming established as accessories or embedded, i.e. integrated in mobiles.

Two explicit trends continue to emerge, which underline the consistently great importance of LEDs in the mobile sector. First of all, there is a demand for ever smaller LEDs, which provide background lighting or animation in mobile phone covers. Secondly, high-performance LEDs are needed to enable integrated image projectors or powerful flash functions. Furthermore, the infrared sector will become even stronger due to the demand for IR components, such as, for instance, brightness, tilt or proximity sensors. We are especially working on sensor systems, flash and projection.

In mobile end consumer devices, OSRAM Opto Semiconductors insists on quality and innovation. One example of this is our thin-film chip technology. It ensures that almost the entire light produced is emitted upwards. This is the basis for highly efficient and powerful LEDs, which are used for projection or flash functions. Only with innovations of this kind, LEDs are capable of making the most of their strengths, such as efficiency, power and durability, without drawing too much on the devices' batteries. Another interesting future area for us is "near to eye" projection, where images are transmitted wirelessly from the mobile device via eyeglasses to the field of view. This kind of technology can elevate the functions and options of a mobile device and its applications to a new level.

As a provider in such a dynamic market, it is important to remain flexible at all times, to have a wide range available for various applications and to identify the specific future desires of customers. The light of LEDs and opto-semiconductors will continue to play a major role in customising the design of mobile devices and in extending their functionality.

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