GENERAL ILLUMINATION
LUXEON Z UV
Assembly and handling information
Introduction
This application brief addresses the recommended assembly and handling
procedures for LUXEON Z UV emitters. Proper assembly, handling, and thermal
management, as outlined in this application brief, ensure high optical light output
and long light output maintenance for LUXEON Z UV emitters.
Scope
The assembly and handling guidelines in this application brief apply to all the
LUXEON Z UV part numbers LHUV-abbb-cddd where:
a–
bbb –
c–
ddd –
for future additional requirements for this product
beginning of peak wavelength bin in 5nm interval
(e.g. 395 designates 395–400nm range)
for future additional requirements for this product
minimum total radiometric power in mW (e.g. 500 refers to min 500mW)
AB114 LUXEON Z UV Application Brief ©2015 Lumileds Holding B.V. All rights reserved.
Table of Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1 . Component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
1.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
1.2 Optical Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.3 Handling Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.4 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.5 Electrical Isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.6 Mechanical Files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.7 Soldering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
2 . LUXEON Z UV Printed Circuit Board Design Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
2.1 LUXEON Z UV Footprint and Land Pattern. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Surface Finishing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
2.3 Minimum Spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3 . Thermal Measurement Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3.1 Thermal Basics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3.2 Temperature Sensor Pad (T
s
) and Thermocouple (TC) Attachment . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3 Effect of Placing T
s
Point Further Away from LED Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
3.4 Thermal Measurement Result. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4 . Assembly Process Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4.1 Stencil Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4.2 Solder Paste . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4.3 Solder Paste Screen Printing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
4.4 Pick-and-Place . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
4.5 Reflow Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
5 . Packaging Considerations — Chemical Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
About Lumileds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
AB114 LUXEON Z UV Application Brief 20150330 ©2015 Lumileds Holding B.V. All rights reserved.
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1. Component
1.1 Description
The LUXEON Z UV emitter is an ultra-compact, surface mount, high-power ultra-violet (UV) LED with peak wavelength
ranging from 380nm to 430nm. Each LUXEON Z UV emitter consists of a high brightness InGaN chip on a ceramic
substrate. The ceramic substrate provides mechanical support and provides a thermal path from the LED chip to the
bottom of the emitter. An interconnect layer electrically connects the LED chip to cathode and anode pads of equal size on
the bottom of the ceramic substrate. The cathode of the LUXEON Z UV emitter is marked with a small notch in the center
of the electrode (see Figure 1).
The top of the LUXEON Z UV is covered with a layer of silicone to shield the chip from the environment. The bottom of the
LUXEON Z UV emitter contains two equally sized metallization pads for the anode and cathode.
All LUXEON Z UV emitters contain a transient voltage suppressor (TVS) chip which protects the LED chip against
electrostatic discharge (ESD) events. The top surface of the LUXEON Z UV emitter has a flat top surface as shown
in Figure 1.
As with any other UV light source, proper safety precautions must be followed to protect eyes and skin from UV exposure
when operating these light sources. A UV caution label is attached to each reel shipped.
Figure 1. 3D renditions of LUXEON Z UV. Top view (left) and bottom view (right).
AB114 LUXEON Z UV Application Brief 20150330 ©2015 Lumileds Holding B.V. All rights reserved.
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1.2 Optical Center
The theoretical optical center of the LUXEON Z UV emitter is 0.625mm from the top and 0.650mm from the side edges of
the ceramic substrate (see Figure 2).
Note that when designing secondary optics for LUXEON Z UV emitters, the lens material selected should be able to
withstand prolonged UV exposure. For example, a lens which is made of untreated standard grade polycarbonate (PC)
absorbs UV light and turns yellowish over time, which, in turn, reduces the light output performance of the whole LED
system. Lumileds recommends that customers discuss the impact of prolonged exposure to UV light with lens suppliers
when selecting appropriate lens materials.
1.3 Handling Precautions
The LUXEON Z UV emitter is designed to maximize light output and reliability. However, improper handling of the emitter
may damage the LED chip and affect the overall performance and reliability. In order to minimize the risk of damage to
the LED chip during handling, LUXEON Z UV emitters should only be picked up manually from the side of the ceramic
substrate as shown in Figure 3.
When handling finished boards containing LUXEON Z UV emitters, do not touch the top surface with any fingers (see
Figure 4a) or apply any pressure to it. Also, do no turn over the board for probing, if the electrodes are at the back of the
board, or stack multiple boards on top of each other (see Figure 4b). A rough or contaminated surface, which is placed on
top of a LUXEON Z UV emitter, may damage the silicone overcoat of the emitter. Furthermore, any pressure applied onto
the LUXEON Z UV emitter during probing may damage the silicone layer or the chips underneath.
Figure 2. The optical center of the LUXEON Z UV emitter is 0.625mm from the top and 0.650mm from the side edges.
AB114 LUXEON Z UV Application Brief 20150330 ©2015 Lumileds Holding B.V. All rights reserved.
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Figure 3. Correct handling (top) and incorrect handling (top) of LUXEON Z UV emitters.
1.4 Cleaning
The LUXEON Z UV emitter should not be exposed to dust and debris. Excessive dust and debris may cause a drastic
decrease in optical output. In the event that the surface of a LUXEON Z UV emitter requires cleaning, a compressed gas
duster at a distance of 6” away will be sufficient to remove the dust and debris or an air gun with 20 psi (at nozzle) from a
distance of 6”. Make sure the parts are secured first.
If there is any solder flux residue on the top of the package, it may oxidized and turn brown during LED operation. In
general any foreign contamination which is not transparent to blue or UV light should be removed to prevent possible
photo-thermal chemical reaction.
1.5 Electrical Isolation
The LUXEON Z UV emitter contains only two electrical pads on the bottom of the ceramic substrate with a spacing of
0.25mm between them. In order to avoid any electrical shocks and/or damage to the LUXEON Z UV emitter, each design
needs to comply with the appropriate standards of safety and isolation distances, known as clearance and creepage
distances, respectively (e.g. IEC60950, clause 2.10.4).
1.6 Mechanical Files
Mechanical drawings for LUXEON Z UV (2D and 3D) are available on the Lumileds website at
lumileds.com.
1.7 Soldering
LUXEON Z UV emitters are designed to be soldered onto a Printed Circuit Board (PCB). For detailed assembly instructions,
see Section 4.
Figure 4. Do not touch the top of surface of the LUXEON Z UV emitter when handling a finished board (a)
or stack boards with one or more LUXEON Z UV emitters on top of each other (b).
AB114 LUXEON Z UV Application Brief 20150330 ©2015 Lumileds Holding B.V. All rights reserved.
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