Rohm Develops Small LED Device Using Surface-mount Aspherical Lens

Jul 6, 2013
Motoyuki Oishi, Nikkei Electronics
The LED device equipped with a surface-mount aspherical lens
The LED device equipped with a surface-mount aspherical lens
[Click to enlarge image]

Rohm Co Ltd developed the "CSL0701/0801," an LED device equipped with a small-size, high-output surface-mount lens for use as an auxiliary light source for autofocus in digital cameras and phone cameras.

With its own device manufacturing technology and optical design, Rohm realized the "2924" size (2.9 x 2.4mm), which is one of the smallest in the industry, and reduced footprint and height by 65% and 30%, respectively.

In recent years, there has been an increasing demand for smaller, slimmer electronic components of digital cameras and mobile phones, which are decreasing in size and increasing in performance. In addition, because current increases due to multi-function devices, the need for lower power consumption is growing.

However, with lens-mounted LED devices used as auxiliary light sources for autofocus, it is necessary to apply enough amount of light to a subject so that the focal point can be accurately calculated. For this purpose, a semispherical lens is normally used, making it difficult to reduce size and thickness.

Since Rohm developed a side-view LED as an auxiliary light source for autofocus for the first time in the industry, the company has been reducing its size and increasing its performance and won a large share. For the new LED device, the company achieved the 2924 size by reducing the size of light-emitting element and employing an optical design using the CAE (computer aided engineering) technology and an aspherical lens based on the company's own molding technology.

In addition, Rohm realized a high output by improving heat radiation performance. When designed with a brightness equivalent to those of previous products, it contributes to lowering current consumption.

Furthermore, the deviation of the optical axis was reduced to ±3° so that light can be accurately applied to a distant object. And the new LED device will be offered in both top-view and side-view packages, increasing design flexibility for customers.

Rohm started to ship samples of the device in January 2013. The price of the sample is ¥500 (approx US$4.99) per unit. And it started volume production with a production rate of 500,000 units per month in June 2013. The manufacturing base for the device is Rohm-Wako Electronics (Malaysia) in Malaysia.