The Peak Light Wavelength is the highest wavelength emitted optically from the LED, while the Dominant Light Wavelength refers to the color shade perceived by the human eye.

Luminous intensity refers to the overall brightness, from a lamp LED, for example, without regard to the area of the light source. Luminance indicates the degree of brightness over an area, such as from a display device. The greater the source area the higher the luminance. The luminance is normally obtained by dividing the luminous intensity by the light source area.

No, some LEDs should not be reflow soldered. Chip LEDs are suitable for reflow, while lamp types (through-hole/leaded) should be flow or dip soldered. Soldering conditions and information are contained in the respective data sheets, and vary by manufacturer.

It is not recommended, since LEDs lack the appropriate buffer materials (i.e. fillers) in order to withstand the temperature tolerances of manual soldering. Please consult a ROHM representative for details.

The reliability of LEDs can be compromised by moisture absorption, which can lead to failures during the soldering process. For this reason humidity control is highly recommended. Please refer to the respective data sheets for additional information.

Although possible, it is not recommended, since directly supplying voltage may, as we have seen above, result in an exponential change in output current, which can cause failure. Therefore, resistors should be connected to limit current.

Yes, provided that low current LEDs are chosen.
Please ensure that the current flow is stable and does not go below 1mA.

One of the major factors that influence LED life is die temperature – the lower the temperature the longer the life.
In order to maintain low LED die temperature the following should be heeded:
 •Keep current flow small
 •Minimize ambient temperature
 •Design for sufficient heat dissipation

LEDs in general are not designed to be used outdoors.
Adequate moisture treatment, temperature management, UV filtering, salt air protection, and the like should be provided if intended for outdoor use.

LED life may be significantly affected.
In some cases the luminous intensity my drop for a few hours or may completely turn OFF.