-7-

(6) Heat Generation

· Thermal design of the end product is of paramount importance.

Please consider the heat generation

of the LED when making the system design.

The coefficient of temperature increase per input

electric power is affected by the thermal resistance of the circuit board and density of LED placement

on the board, as well as other components.

It is necessary to avoid intense heat generation and operate

within the maximum ratings given in this specification.

· Please determine the operating current with consideration of the ambient temperature local to the LED

and refer to the plot of Ambient temperature vs. Allowable Forward Current on CHARACTERISTICS

in this specifications. Please also take measures to remove heat from the area near the LED to improve

the operational characteristics of the LED.

· The equation 1 indicates correlation between Tj and Ta, and the equation 2 indicates correlation

between Tj and Ts1.

Tj=Ta + Rja W

1

Tj=Ts1 + Rjs1 W

2

Tj = Dice Temperature : °C, Ta = Ambient Temperature : °C,

Ts1 = Solder Temperature (Cathode Side) : °C,

Rja = Heat resistance from Dice to Ambient temperature : °C /W,

Rjs1 = Heat resistance from Dice to Ts1 measuring point : °C /W,

(7) Safety Guideline for Human Eyes

· The International Electrical Commission (IEC) published in 2006 IEC 62471:2006 Photobiological

safety of lamps and lamp systems which includes LEDs within its scope. Meanwhile LEDs were

removed from the scope of the IEC 60825-1:2007 laser safety standard, the 2001 edition of which

included LED sources within its scope. However, keep in mind that some countries and regions have

adopted standards based on the IEC laser safety standard IEC 60825-1:2001 which includes LEDs

within its scope.

Following IEC 62471:2006, most of Nichia LEDs can be classified as belonging to either Exempt

Group or Risk Group 1. Optical characteristics of a LED such as output power, spectrum and light

distribution are factors that affect the risk group determination of the LED. Especially a high-power

LED, that emits light containing blue wavelengths, may be in Risk Group 2.

Great care should be taken when viewing directly the LED driven at high current or the LED with

optical instruments, which may greatly increase the hazard to your eyes.

Nichia STS-DA1-0230C

<Cat.No.090428>