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Application Note

Handling of the OSRAM OSTAR® Projection Power

Abstract

The OSRAM OSTAR® Projection Power family LEDs offerhighest luminance and are specially designed for projectionapplications. Different versions and designs offer the bestimplementation possible in the application. In addition tothermal management, correct handling and processing of theLEDs are essential for a successful application. This applicationnote provides a recommendation for the appropriate handlingand processing of the different versions of the LED family.

Valid for:OSRAM OSTAR® Projection Power

Author: Retsch Stefanie / Jiang, DeGen

Further information:AN053_Thermal management of OSRAM OSTAR® Projection light sources AN084_Projection with LED light sources

Application Note No. AN149

www.osram-os.com

Table of contents

A. Basic information ....................................................................................................2

Mechanical and optical design resources ..........................................................3

B. General Handling recommendations ......................................................................4

ESD stability ........................................................................................................4

Cleaning ..............................................................................................................4

Precautions and storage .....................................................................................5

C. OSRAM OSTAR® Projection Power with connecting board ..................................5

Delivery ...............................................................................................................7

Handling recommendations ................................................................................7

Assembly of the connector .................................................................................9

D. OSRAM OSTAR® Projection Power SMT ............................................................13

Handling recommendations ..............................................................................14

Solder pad design .............................................................................................15

Solder stencil ....................................................................................................16

Reflow soldering ...............................................................................................16

A. Basic information

OSRAM OSTAR® Projection devices are optimized for Étendue-limited systemsthat require the highest achievable luminance, such as projection applications.Since an encapsulation with a material comprising a refractive index >1 may leadto an increase in effective Étendue, the chips radiate directly into air. To protectthe chips, either a glass cover or a frame with protective tape (which must beremoved before operation) is used.

The design of the OSRAM OSTAR® Projection light source is also focused onthermal optimization, as for the highest current density of max 6A/mm² efficientcooling is necessary. Please refer to the data sheet for the individual current ofeach LED.

OSRAM OSTAR® Projection Power devices offer lowest thermal resistance asthe chips are mounted directly on a copper substrate. Since an adequate thermal

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management is indispensable, please refer to the Application Note“AN053_Thermal management of OSRAM OSTAR® Projection light sources”.

Table 1 shows a product selector guide to find the recommended product for theindividual applications.

Mechanical and optical design resources

For detailed information about the mechanical dimensions of the OSRAMOSTAR® Projection Power devices please refer to the detailed drawingsavailable in the data sheet. To obtain CAD data and optical rayfile, please visitthe “Optical Simulation / Ray Files + Package CAD Data” webpage on theOSRAM Opto Semiconductor website.

For more information on importing rayfiles and ray-measurement files of LEDsfrom OSRAM Opto Semiconductors, please refer to the application note“AN086_Importing rayfiles and ray-measurement files of LEDs from OSRAMOpto Semiconductors”.

The newest generation of OSRAM OSTAR® Projection Power devices come witha protective tape covering the chip area (Figure 1) for the deep blue, blue and

Table 1: Product selector guide

Application OS

RA

M O

ST

AR

®

Pro

ject

ion

Cub

e

OS

RA

M O

ST

AR

®

Pro

ject

ion

Co

mp

act

OS

RA

M O

ST

AR

®

Pro

ject

ion

Po

wer

Em

bed

ded

so

luti

ons

Camera

Smartphones

Tablets

Co

mp

act

solu

tio

ns

Home cinema

Gaming

Notebook accessory

Control room

Head-up display

Bus

ines

s so

luti

ons

Office

Education

Professional

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amber devices. This tape also protects the LED during the soldering process andshould be left in place until initial operation.

Figure 1: Protective tape for deep blue, blue and amber colored OSRAM OSTAR® Projection Power

B. General Handling recommendations

The use of any type of sharp objects should generally be avoided, since this candamage the component. Generally the LED light-emitting area should not betouched or punctured as this can damage the component.

ESD stability

All OSRAM OSTAR® Projection devices offer a build-in 2kV ESD providing ESDstability of up to 2 kV. It is assigned to the “Class 2 HBM” category in accordancewith ANSI / ESDA / JEDEC JS-001. With this class the LED can be consideredas uncritical for processing and assembly by state-of-the-art SMT equipmentaligned with ESD precautions. To achieve higher ESD protection on the systemlevel, additional ESD protection must be applied.

Nevertheless, please be aware of ESD safety precautions while handling LEDs.As a matter of principle, common ESD safety precautions must be observedduring the handling, assembly and production of electronic devices (LEDs). Forfurther information about ESD protection please refer to the application note“ESD protection while handling LEDs”.

Cleaning

Any direct mechanical or chemical cleaning of the LED should be avoided. Fordusty LEDs, simple cleaning by means of purified compressed air (e.g. centralsupply or spray can) is recommended. In order to ensure that the compressedair does not contain any oil residues, the use of a spray can is recommended. Amaximum pressure of 4 bar at a distance of 20 cm to the component is alsorecommended.

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Precautions and storage

For storage and dispatch, the reels or trays are packed in vacuum-sealed drybags together with desiccants. It is generally recommended to leave reels in theiroriginal packaging until they are assembled, and to store components underambient conditions of ≤ 10 % RH during processing. Drying cabinets with drynitrogen (N2) or dry air are suitable for this type of storage. The product complieswith moisture-sensitive Level 2 (MSL 2) according to JEDEC J-STD- 020E. Formore information please refer to the application note “Dry pack information”.

As is the case for all LEDs from OSRAM Opto Semiconductors, the product alsofulfills the current RoHS guidelines (European Union and China) and thereforecontains no lead or other defined hazardous substances.

Since the OSRAM OSTAR® Projection Power is generally supplied on tape or ona tray with a dry pack, it should be factory-sealed when stored. The hermeticallysealed package should only be opened immediately before mounting andprocessing, after which the remaining LEDs should be repacked in accordancewith the moisture level specified in the data sheet (see JEDEC J-STD-033 —Moisture Sensitivity Levels).

A suitable storage system should be implemented in order to ensure thatassembled LED boards are not stacked on top of each other (Figure 2). To avoidthe risk of damage to the assembled LEDs, make sure that they are not exposedto compression forces of any kind. Furthermore, the LED of the assemblies mustalso not be touched directly.

Figure 2: Correct storage

C. OSRAM OSTAR® Projection Power with connecting board

The OSRAM OSTAR® Projection Power devices on a connecting board areavailable in three different colors:

• Deep Blue / Blue

• Amber

• Converted Green

Figure 3 shows an overview of the standard OSRAM OSTAR® Projection Powerdevices witha connecting board. Amber and (deep) blue devices are coveredwith a glass window, the converted green LED is cast in silicone.

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Figure 3: Overview of standard OSRAM OSTAR® Projection Power devices

The newest generation of devices provides series connection of chips whichleads to a reduction of the absolute forward current, and therefore to a lower LEDdriver complexity and a smaller connector size. The devices also have apotential-free LED backside and the amber and (deep) blue devices arewindowless. This avoids losses due to cover reflectivity and stray light. Figure 4shows an overview of all the devices of this class.

Figure 4: Overview of new generation OSRAM OSTAR® Projection Power with a connecting board

LE CG P2ALE CG P1A LE CG P3A

LE B P1W LE B P2W LE B P3W

LE A P1W LE A P2W LE A P3W

LE CG P2AQLE CG P1AQ LE CG P3AQ

LE B P1MQ LE B P2MQ LE B P3MQ

LE A P1MQ LE A P2MQ LE A P3MQ

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Figure 5 shows the principal design of the OSRAM OSTAR® Projection Powerdevices with connecting board. All the devices are available as a 2-chip, 4-chipor 6-chip light source, mounted on an IMS with drilled holes for mounting andconnector pads for electrical connections.

Figure 5: Principal design of the OSRAM OSTAR® Projection Power with a connecting board

Delivery

The OSRAM OSTAR® Projection Power devices on IMS-PCB (Insulated MetalSubstrate) will be delivered on trays, like illustrated in Figure 6. OSRAM OptoSemiconductors can be contacted for a detailed drawing.

Figure 6: Example of a tray

Handling recommendations

In addition to general guidelines on the handling of LEDs, additional care shouldbe taken that mechanical tension on the carrier board and especially stress (e.g.sheering forces) on the glass cover or ceramic are avoided. This means, that theLED must not be picked up or handled by the glass or ceramic.

In general, any type of sharp object (e.g. forceps, fingernails, etc.) should beavoided in order to prevent stress to, or penetration of, the encapsulation sincethis can lead to damage to the component. Exerting pressure on the elasticGlobe-Top can lead to the spontaneous failure of the LED (damage to thecontacts).

IMSConnector pads for electrical connections

Protective tape

Frame

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Care should be taken that the light-emitting area is not touched or contaminatedin any way. Figure 7 shows the critical area that should be not touched orcontaminated.

Figure 7: Keep out area

The handling of the products using finger cots or anti-static plastic gloves isrecommended to avoid contamination of the products, especially in the keep-outarea. If the products are handled using tweezers, a round-end type isrecommended. The tips of the tweezers must be kept away from the solder padand the keep-out area. Avoid the use of sharp-end type tweezers which maydamage the surface of the products. Figure 8 shows the recommendations formanual handling.

Figure 8: Manual handling recommendations

Keep out, don‘t touch area

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For the connection to the heat sink, please use thermal interface material (fordetailed information on thermal interface material, please refer to ApplicationNote “AN053_Thermal management of OSRAM OSTAR® Projection lightsources”). The devices can be connected to the heat sink with a screw.

When mounting the MPCB to the frame or heatsink by means of a screw, metriccylindrical head screws M1.4 can be used for the mounting and it is generallyrecommended that a locking compound are used for each screw. Whenmounting the screws (M1.4), it is recommended that you check on the maximumtorque with the screw supplier. Additionally, to avoid MPCB bending which canhave an adverse effect on the thermal interface material and the LED itself, amaximum torque of 0.2 Nm should be used. There are 4 holes on the MPCB, andit is recommended to use 2 diagonal holes for mounting and another 2 holes foraligning them with the register pins.

Assembly of the connector

In order to be able to connect the individual components, the IMS provides pinsfor assembling a connector. The recommended connector for each componentcan be found in the respective data sheet. Figure 9 shows an assembledconnector.

Figure 9: Assembled connector

It is common in industry to use carriers or pallets for the entire SMT assemblyprocess (solder paste printing, connector placement, reflow soldering) whenprocessing PCB-based components. These carriers are typically made of highlyheat-resistant, fiber-reinforced material. The cut-outs, which fit the componentprecisely, hold the components in place. This enables a stable and reproducibleassembly with a good soldering process. Figure 10 shows a sketch of a possiblecarrier.

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Figure 10: Sketch of a possible carrier

In order to obtain an effective soldering process, it is recommended to place thecomponents with the pins opposite each other.

Before solder paste printing can be performed, the component must be maskedand the light-emitting part must be protected. Here it is recommended to use astep-down stencil. This should have a suitable integrated cavity for the sensitiveLED part of the PCB to protect it during the process. Figure 11 shows a sketchof a possible step-down stencil.

Figure 11: Sketch of a step-down stencil with integrated cavity

The use of special slit squeegee blades is required for solder paste printing.Figure 12 shows a possible arrangement of the carrier and step-down stencil.

Step-down on squeegee side

Integrated cavity

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Figure 12: Arrangement of the carrier and step-down stencil

These are slotted and matched to the step-down stencil and the design of thecorresponding carrier (see Figure 13).

(Further information on this procedure can be requested from company ChristianKoenen GmbH, for example.)

Figure 13: Example of a special squeegee blade

A correct solder paste print is the basis for the assembly with the correspondingSMT connector. This process can be performed manually, but it isrecommended that automated assembly with a pick-and-place machine is usedfor mass production.

For the OSRAM OSTAR® Projection Power, a standard reflow soldering processwith forced convection can be applied. Since the soldering atmosphere and inparticular air reflow can cause degradation of optical parameters it is advisableto use an N2 atmosphere (<500 ppm O2). Figure 14 shows the temperatureprofile for lead-free soldering with the recommended peak temperature of245 °C. Due to the high thermal mass of the Cu based substrate it is notrecommended to perform manual soldering with a soldering iron or heating guns.

Slit squeegee blade

Step-down stencil

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Figure 14: Maximum and recommended solder temperature for soldering the connector to the PCB in accordance with to JEDEC J-STD-020E

0 50 100 150 200 250 300

t [s]

0

50

100

150

200

250

300

25

T [°C]

up to 120 s

up to 30 s

up to 100 s

Ramp up3 K/s (max)

Ramp down6 K/s (max)

245 °C Recommended solder profile(max 260 °C)

217 °C

240 °C

Profile Feature SymbolPb-Free (SnAgCu) Assembly

UnitMin Recommended Max

Ramp-up rate to preheat[1]

25 °C to 150 °C

2 3 K/s

Time tS TSmin to TSmax

tS 60 100 120 s

Ramp-up rate to peak[1] TSmax to TP

2 3 K/s

Liquidus temperature TL 217 °C

Time above liquidus temperature tL 80 100 s

Peak temperature TP 245 260 °C

Time within 5 °C of the specified peak temperature TP - 5 K

tP 10 20 30 s

Ramp-down rate[1]

TP to 100 °C

3 6 K/s

Time 25 °C to TP

480 s

All the temperatures refer to the center of the package, measured on the top of the component[1]slope calculation DT/Dt: Dt max. 5 s; fulfillment for the whole T-range

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D. OSRAM OSTAR® Projection Power SMT

OSRAM OSTAR® Projection Power SMT devices (LE x P0MQ/AQ) come with acopper substrate which offers lowest thermal resistance. These devices alsocomprise a large electrical isolated thermal pad for better thermal dissipation.The amber and (deep) blue devices are windowless to avoid light losses due tocover reflectivity and stray light. The converted green LED is cast in silicon toensure maximum system level efficiency.

OSRAM OSTAR® Projection Power SMT devices have a protective tapecovering the chip area (Figure 15) for the (deep) blue and amber devices. Thistape also protects the LED also during the soldering process and should be leftin place until initial operation.

Figure 15: Protective tape for (deep) blue and amber colored OSRAM OSTAR® Projection Power

Figure 16 shows an overview of all the OSRAM OSTAR® Projection Power SMTdevices

Figure 16: Overview of OSRAM OSTAR® Projection Power SMT devicesLE CG P0AQLE A P0MQ

LE B P0MQ LE D P0MQ

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Handling recommendations

Please be aware of ESD safety while handling the LED (see Application Note“ESD protection while handling LEDs”). In addition to the general guidelines forthe handling of LEDs, additional care should be taken that mechanical stress(e.g. sheering forces) on to the elastic silicone encapsulation is eliminated orreduced to the greatest extent possible (see also application note “Handling ofsilicone resin LEDs”).

Although manual handling and assembly is possible, automatic placement ishighly recommended. For manual assembly and placement — in the productionof prototypes, for example — the diligent use of tweezers is recommended. TheLED must not be lifted from the top, because this may cause damage to thesurface. In addition, it is recommended to hold the LED metal substrate by usingtweezers and applying any force equally to the entire LED package as shown inFigure 17. If there is no alternative to the use of tweezers, the LED can be pickedand handled at the metal substrate using finger cots or anti-static plastic gloves.

In general, any type of sharp objects (e.g. forceps, fingernails, etc.) should beavoided in order to prevent stress to, or penetration of, the encapsulation sincethis can lead to the impairment of the component.

Figure 17: Recommended manual handling

When processing by means of automated placement machines, care should betaken to use an appropriate pick-and-place tool and to ensure that the processparameters comply with the package's characteristics. An example of a suitablepick-and-place nozzle is given in the form of the ASM SIPLACE tool number308199. Figure 18 shows the recommended nozzle.

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Figure 18: Recommended pick-and-place nozzle from ASM SIPLACE

Solder pad design

Since the solder pad effectively creates the direct contact between the LED andthe circuit board, the design of the solder pad contributes decisively to theperformance of the solder connection. The design has an influence on solderjoint reliability and heat dissipation, for example. In most cases, it is thereforeadvantageous to use the recommended solder pad, since it is individuallyadapted to the properties and conditions of the LED (Figure 19). Thecorresponding solder pad can also be found in the data sheet of each LED.

Figure 19: Recommended solder pad design

Based on the given solder pad design, an optimized balance between goodprocessability, the smallest possible positioning tolerance and a reliable solderconnection can be achieved.

SIPLACE Nozzle 3081899

1.052.4

1.25

0.78

0.3

2.3

30.3

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Solder stencil

In the SMT process, solder paste is normally applied by stencil printing. Thedesign of the printing stencil and an accurate working process greatly influencethe applied amount and quality of the paste deposit. Figure 20 shows anexample of a printed circuit board with good solder paste printing.

Figure 20: Example of good solder paste printing

Proper solder paste printing increases the solder quality. Effects such as solderbridges, solder balling, solder spray and/or other soldering defects are largelydetermined by the design of the stencil apertures and the quality of the stencilprinting (e.g. positioning, cleanliness of the stencil, etc.). For the OSRAMOSTAR® Projection Power a stencil thickness of 120 μm is recommended. Auniform solder joint thickness is also recommended in order to produce reliablesolder joints and obtain an appropriate optical alignment.

For the paste printing process OSRAM Opto Semiconductors has successfullyused the standard SAC 305 Type 3 solder paste (HERAEUS F640 SAC 305Type 3). For process evaluation, process control and failure prevention it isrecommended to check the solder paste volume with SPI (Solder PasteInspection) regularly.

Reflow soldering

Since the OSRAM OSTAR® Projection Power is generally compatible withexisting industrial SMT processing methods, current populating techniques canbe used for the mounting process. The individual soldering conditions for eachLED type in accordance with to JEDEC can be found in the respective datasheet. A standard reflow soldering process with forced convection understandard N2 atmosphere (<500 ppm O2) is mandatory for mounting thecomponent, in which a typical lead-free SnAgCu metal alloy is used as solder.Figure 21 shows the temperature profile for lead-free soldering with therecommended peak temperature of 245 °C. In this context, it is recommendedto check the profile on all new PCB materials and designs. As a good startingpoint, the recommended temperature profile provided by the solder pastemanufacturer can be used. The maximum parameters and temperature for theprofile as specified in the data sheet should not, however, be exceeded.

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Figure 21: Temperature profile for lead-free reflow soldering in accordance with JEDEC J-STD-020E

Vacuum reflow option. If a very low level (<10%) needs to be achieved, avacuum reflow soldering oven can be used.

To ensure optimized heat transfer from the integrated thermal pad to the PCBand high board level reliability, it is recommended to control the solder jointquality of the first assembled samples with an X-ray image. The X-ray images inFigure 22 show good solder joint quality with no bridging and very low voiding.

Figure 22: X-ray images of the solder joint quality

0 50 100 150 200 250 300

t [s]

0

50

100

150

200

250

300

25

T [°C]

up to 120 s

up to 30 s

up to 100 s

Ramp up3 K/s (max)

Ramp down6 K/s (max)

245 °C Recommended solder profile(max 260 °C)

217 °C

240 °C

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ABOUT OSRAM OPTO SEMICONDUCTORS

OSRAM, Munich, Germany is one of the two leading light manufacturers in the world. Its subsidiary, OSRAMOpto Semiconductors GmbH in Regensburg (Germany), offers its customers solutions based on semiconduc-tor technology for lighting, sensor and visualization applications. OSRAM Opto Semiconductors has produc-tion sites in Regensburg (Germany), Penang (Malaysia) and Wuxi (China). Its headquarters for North Americais in Sunnyvale (USA), and for Asia in Hong Kong. OSRAM Opto Semiconductors also has sales offices th-roughout the world. For more information go to www.osram-os.com.

DISCLAIMER

PLEASE CAREFULLY READ THE BELOW TERMS AND CONDITIONS BEFORE USING THE INFORMA-TION SHOWN HEREIN. IF YOU DO NOT AGREE WITH ANY OF THESE TERMS AND CONDITIONS, DONOT USE THE INFORMATION.

The information provided in this general information document was formulated using the utmost care; howe-ver, it is provided by OSRAM Opto Semiconductors GmbH on an “as is” basis. Thus, OSRAM Opto Semicon-ductors GmbH does not expressly or implicitly assume any warranty or liability whatsoever in relation to thisinformation, including – but not limited to – warranties for correctness, completeness, marketability, fitnessfor any specific purpose, title, or non-infringement of rights. In no event shall OSRAM Opto SemiconductorsGmbH be liable – regardless of the legal theory – for any direct, indirect, special, incidental, exemplary, con-sequential, or punitive damages arising from the use of this information. This limitation shall apply even ifOSRAM Opto Semiconductors GmbH has been advised of possible damages. As some jurisdictions do notallow the exclusion of certain warranties or limitations of liabilities, the above limitations and exclusions mightnot apply. In such cases, the liability of OSRAM Opto Semiconductors GmbH is limited to the greatest extentpermitted in law.

OSRAM Opto Semiconductors GmbH may change the provided information at any time without giving noticeto users and is not obliged to provide any maintenance or support related to the provided information. Theprovided information is based on special conditions, which means that the possibility of changes cannot beprecluded.

Any rights not expressly granted herein are reserved. Other than the right to use the information provided inthis document, no other rights are granted nor shall any obligations requiring the granting of further rights beinferred. Any and all rights and licenses regarding patents and patent applications are expressly excluded.

It is prohibited to reproduce, transfer, distribute, or store all or part of the content of this document in any formwithout the prior written permission of OSRAM Opto Semiconductors GmbH unless required to do so in ac-cordance with applicable law.

OSRAM Opto Semiconductors GmbH

Head office:

Leibnizstr. 493055 RegensburgGermanywww.osram-os.com

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