CAUTIONS for Power LED

Storage

n The storage ambient should not exceed 30℃ temperature or 70% relative humidity.

n For extended storage out of their original packaging, it is recommended that the LEDs be stored 

in a sealed container with appropriate desiccant, or in a desiccator with nitrogen ambient.

n It is recommended that LEDs out of their original packaging are soldered within 4weeks.

n LEDs stored out of their original packaging for more than 4 weeks should be baked at about 60 

deg C for at least 24 hours before solder assembly.

Assemble Consideration

This section provides you the requirements to mount BL-HP Emitters onto Metal Core Printed 

Circuit Board （MCPCB）for optimal heat-dissipation efficiency, for reliable operations of your 

products and for the optimal performance you need.

n Design rules during BL-HP Emitter array and its assembly procedure

1. Thermal resistance from the BL-HP Emitters to the ambient environment must be kept at minimum 

level as possible. Any heat barrier will prevent BL-HP Emitters from running at optimum light output 

performance.

2. Electrical insulation between the contacts other than electros of BL-HP Emitters and the MCPCB 

is required. The exposed metal part of a BL-HP Emitters is not electrically neutral. Do not electrically 

connect this area to any electrical traces or pads on your MCPCB.

3. If you want to minimize thermal resistance between BL-HP Emitters and your MCPCB, use 

thermally conductive adhesive in-between.

4. BL-HP Emitter can be soldered in infrared (IR), hot bar soldering, fiber focused IR, or hand 

soldering.

MCPCB Selection

To select a suitable MCPCB is the first step in assemble BLHP emitters. A MCPCB consists of

several layers that provide both electrical connections and a low thermal resistance path to external

heat sinks applied. Standard BLHP Emitter arrays use aluminates MCPCB that consists of the

following layers:

1.Aluminum Base ( thickness:1.5±0.1mm)

2. Electrical Insulation Layer (Dielectric/Epoxy thickness: 100µÌ)

3. Copper Layer (Copper thickness: 35µÌ

4. Solder Mask (Solder paste thickness after reflow process: 90~115µÌ

Thermal Consideration

n Thermal Resistance of BLHP Emitter

    Thermal resistance (RTH) is one of the primary tools used in thermal management design. It is  

    defined as the ratio of temperature difference to the corresponding power dissipation. The overall

 RTH,J-A (Junction-Ambient) of a BLHP Emitter plus MCPCB is illustrated as follow:

(1) RTH,J-A (℃/W) = △TJ-A / P d

Where

△ TJ-A = TJunction - TAmbient (℃)

Pd (Power dissipated, W) = Forward current (IF) × Forward voltage (VF)

In addition, heat generated at the junction of semiconductor die travels along the following path to

 ambient environment: junction-to-board, board-to-ambient air.

Soldering Process

Followings are a recommend process flows to build BLHP Emitters into Power Light Sources. 

Please mount entire respective surface mount devices （SMD）, if any, on your MCPCB designated

 before BLHP Emitters assembly process.

n For IR Reflow Soldering

Reflow soldering temperature profile

For Hot Bar

Step 1 Dispense Thermal Conductive Agent and Solder Flux

Use solder flux for good heat transfer during soldering of the BLHP Emitter terminals to reduce 

required soldering time. Note that the spread of flux compound should be restricted to the solder pad 

areas. You may want to optimize your soldering process by adjusting the amount of flux.

Step 2 Placement of BLHP Emitter

It is recommended to use automated pick-and-place equipment to place BLHP Emitters onto MCPCB.

 The pick-and-place mechanism shall not touch the leads or the leads of BLHP Emitters.

Step 3 Soldering the Electrical Leads by Hot bar Soldering

This process will help transfer heat only on to the leads and solder pad areas and therefore avoid 

damaging emitter body. To transfer sufficient heat from hot bars to device-leads, it is strongly 

recommended that the following process parameters must be considered:

1)Amount of flux dispensed onto solder pads, 

2) pressing force of hot bar tips, and 

3)Hot bar temperature.

Step 4 Curing for Thermal Conductive Agent

Please follow the curing instructions set forth by manufacturers for the chosen thermal conductive

 agent.

n For Manual Soldering Iron

When manual hand soldering is concerned, it is recommended to hand solder the leads with a 

solder-tip temperature of 290℃ for less than 3 seconds and at least 2 seconds or more intervals 

during each solder. Furthermore , avoid damaging the emitter or the epoxy layer on MCPCB

ESD (Electrostatic Discharge)

Static Electricity or power surge will damage the LED.

Suggestions to prevent ESD damage:

n Use a conductive wrist band or anti-electrostatic glove when handling these LEDs

n All devices, equipment, and machinery must be properly grounded

n Work tables, storage racks, etc. should be properly grounded

n Use ion blower to neutralize the static charge which might have built up on surface of the LED's

 plastic lens as a result of friction between LEDs during storage and handling

ESD-damaged LEDs will exhibit abnormal characteristics such as high reverse leakage current, 

low forward voltage, or “no light on” at low currents. To verify for ESD damage, check for “light on” 

and Vf of the suspect LEDs at low currents.

The Vf of “good” LEDs should be>2.0V@0.1mA for InGaN product and >1.4V@0.1mA for AlInGaP

 product.

Power source for LEDs (5v/12v/24v AC/DC converter, DC/DC converter, waterproof/non-waterproof)

more information of LED power supplier