CCK-6XPE,CCK-6XPE pdf中文资料,CCK-6XPE引脚图,CCK-6XPE电路-Datasheet-电子工程世界

文档预览

CLD-AP63 rev 6 JAnuAry, 2018

Support Document

Cree

XLamp

LEDs

Chemical Compatibility

figure 1: XLamp

LED discolored as a result of exposure to incompatible chemicals

TabLE of ConTEnTs

executive Summary ......................................................................1

Background and Introduction .......................................................2

examples of Chemical Incompatibility ........................................3

reversibility of vOC-Based Discoloration....................................6

Material Selection Considerations ...............................................8

Chemical Compatibility Testing ...................................................9

Chemical Compatibility Test Procedure ................................11

evaluation ................................................................................12

Provide Post-Test Information to Cree ..................................12

Chemical Compatibility Test Kit Availability ..........................13

Conclusion...................................................................................13

Helpful Links................................................................................13

Appendix ......................................................................................14

EXECuTivE summary

The presence of incompatible volatile organic compounds

(vOCs) in LeD-based solid-state lighting (SSL) designs can impair

the performance and reduce the lifetime of these illumination

systems. Glues, conformal coatings, O-rings, gaskets, and

potting compounds are examples of materials frequently used

in the construction of LeD-based luminaires or lamps and often

contain vOCs. The presence of chemically incompatible vOCs

on or near LeDs can degrade the light output levels or cause

changes in the chromaticity point of the light. The photograph

in Figure 1 above is an example of this vOC degradation on

the surface of an LeD. This sensitivity to vOCs is not unique to

one LeD manufacturer but is a known problem for all types of

blue, royal blue and white-light LeDs. Chemical incompatibility

in SSL is often a localized phenomenon that occurs in luminaire

designs that seal portions of the system, resulting in an LeD

operating environment having elevated temperatures with little

or no air movement. However, with proper design and adequate

testing, chemical incompatibility effects can be prevented.

Cree maintains lists of chemicals known to be incompatible with

www.cree.com/Xlamp

XLamp LeDs and has partnered with materials manufacturers

to inform our customers with information on acceptable

materials. These lists are in the Appendix at the end of this

document. Customer testing is a good way to further develop

an understanding of chemical incompatibilities of a new LeD

and XLamp

are

registered trademarks and the Cree logo is a trademark of Cree, Inc. Other trademarks, product, and company names are the property of their respective

owners and do not imply specific product and/or vendor endorsement, sponsorship or association. This document is provided for informational

purposes only and is not a warranty or a specification. For product specifications, please see the data sheets available at www.cree.com. For warranty

information, please contact Cree Sales at sales@cree.com.

Cree, Inc.

4600 Silicon Drive

Durham, NC 27703

USA Tel: +1.919.313.5300

XLamp

LED ChEmiCaL CompatibiLity

lighting design. With proper material selection design and testing, chemical incompatibility effects can be minimized or removed from

SSL designs.

baCkgrounD anD inTroDuCTion

Most SSL luminaire types are implemented with a blue light LeD chip covered with a yellow phosphor and silicone encapsulant to convert

the blue light to a broader white light spectrum. This entire LeD assembly is covered by a silicone-based lens. Figure 2 is a cross-section

drawing of a typical lighting-class LeD.

Silicone Lens

Blue LED Chip

Covered by Phosphors

& Silicone Encapsulant

Cathode

Tsp

Anode

Substrate

figure 2: Cross-sectional structure of a typical lighting-class LED

The unique silicone polymers utilized in LeDs have excellent light transmittance characteristics: stable over wide temperature ranges,

resistant to yellowing due to ultraviolet (uv) exposure and easily molded. This results in a high-performance yet cost-effective LeD. The

basic structure of the LeD’s lens and encapsulants is a silicone polymer, which is a stable chemical compound.

Any vOCs present in an SSL system can diffuse into the gas-permeable silicone lens and encapsulants of the LeD. Within the molecular

structure of these silicone materials, the vOCs will occupy a free space in the interwoven silicone polymer. With subsequent exposure

to high photon energy emitted from the LeD, along with the heat from the lighting system and the environment, the volatile compounds

trapped in the LeD‘s lens or encapsulants can discolor. This discoloration of the trapped vOCs can degrade the light emitted from the

LeD. This discoloration tends to occur in blue, royal blue and white-light producing LeDs that use blue wavelength LeD chips with yellow

phosphors for spectrum conversion. This sensitivity to vOCs is not unique to one LeD manufacturer but is a known problem for all types

of blue, royal blue and white-light LeDs. Chemically induced discoloration is less prevalent and not as noticeable with amber, red and

green LeDs; these color LeDs have longer wavelengths and therefore a lower frequency and produce lower photonic energy compared to

blue LEDs. Photonic energy (E) is defined by the Planck-Einstein equation of E = hf, where h is Planck’s constant and f is frequency, thus

a higher frequency produces a higher photonic energy.

This application note presents:

•

real-world examples of discoloration caused by vOCs

Sources of chemical incompatibility from the general classes of materials used in SSL systems

Discussion and examples of the reversibility of discoloration from vOCs

Cree’s recommended best practices to maintain chemical compatibility

and XLamp

are registered trademarks and the Cree logo is a trademark

of Cree, Inc. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. This

document is provided for informational purposes only and is not a warranty or a specification. For product specifications, please see the data sheets available at www.cree.com. For warranty information,

please contact Cree Sales at sales@cree.com.

XLamp

LED ChEmiCaL CompatibiLity

•

Procedures and test processes for measuring and assessing potential chemical interactions

Chemical incompatibility test results

EXampLEs of ChEmiCaL inCompaTibiLiTy

This section contains multiple examples of real-life discoloration caused by vOCs. Figures 3 and 4 show a luminaire based on six XLamp

Xr-e LeDs. Figure 3 shows the light output at initial turn-on and Figure 4 shows the same luminaire after less than 100 hours of operation.

Figure 4 shows significant yellowing of the light output, which is likely caused by a color shift in the LEDs. It is worth noting the space

have caused this discoloration of the surface of the LeDs.

Your Customer Has Developed a Great

plate is a nearly sealed microenvironment. The most likely explanation is that vOCs

LED Fixture.

But wait …. What Has Happened?

between the circuit board and the external optical

figure 3: XLamp Xr-E LED-based luminaire at initial illumination

figure 4: XLamp Xr-E LED-based luminaire, yellowed after 100 hours

From left to right in Figure 5 is a pictorial representation of a silicone polymer as vOCs are introduced that occupy the free spaces in the

silicone. After exposure to heat and high photonic energy, this introduction results in vOC-based discoloration.

Cree Confidential

pg. 1

Cree Confidential

pg. 2

figure 5: Left to right - silicone chains; voCs occupying free spaces in the silicone;

discoloration as a result of voC exposure to heat and photonic energy

using chemicals containing vOCs in manufacturing SSL systems can result in LeD light quality degradation or even complete luminaire

failure. Figure 6 illustrates the degradation effect from a vOC on the silicone encapsulant that covers the LeD chip.

Cree Confidential

and XLamp

are registered trademarks and the Cree logo is a trademark

of Cree, Inc. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. This

please contact Cree Sales at sales@cree.com.

Appearance of Normal and Discolored LEDs

XLamp

LED ChEmiCaL CompatibiLity

figure 6: Examples of normal (left) and voC degraded LED (right)

The photograph on the left in Figure 6 is the normal appearance of a Cree XLamp LeD. On the right, the same type of XLamp LeD chip has

a pronounced brown discoloration due to exposure to vOCs while in operation with high photonic power output at nominal environmental

temperatures. This discoloration of the encapsulants is on the top of the LeD chip, localized to the area just above the chip surface,

closest to the source of heat and high photon energy. note that discoloration can occur at various points in an LeD’s lifetime; factors that

affect discoloration of vOCs include heat, photonic energy and wavelength. Figure 7 shows several examples of the effects of chemical

incompatibility in the LeDs.

Cree Confidential

Examples of chemical incompatibility with XP

figure 7: a variety of XLamp LEDs showing chemical incompatibility

vOC-based discoloration can occur as a result of outgassing of solid materials. The sequence of pictures in Figure 8 documents just such

a case of chemical incompatibility. Cree investigated the source of LeD discoloration and, even though the LeDs were not in a sealed

environment, an LeD on the luminaire discolored, as shown in the upper left photograph.

Cree Confidential

and XLamp

are registered trademarks and the Cree logo is a trademark

of Cree, Inc. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. This

please contact Cree Sales at sales@cree.com.

XLamp

LED ChEmiCaL CompatibiLity

Materials Used in SSL Luminaires Can Have a Negative Impact

figure 8: sequence of voC investigation

Cree Confidential

The root cause of the problem was revealed as the disassembled unit sat overnight on a white piece of paper. The next day, indication of

outgassing from the small gaskets was evident on the paper, as shown in Figure 9. The gasket material, in close contact with the LeD lens,

offered a source of vOCs, which ultimately led to the LeD’s discoloration. This case demonstrates the importance of testing all chemicals

and materials in the specific application and environment for which they are intended to be used.

Cree Confidential

figure 9: Evidence of voC outgassing from an o-ring

Cree Confidential

and XLamp

are registered trademarks and the Cree logo is a trademark

of Cree, Inc. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. This

please contact Cree Sales at sales@cree.com.

型号	CCK-6XPE	CCK-6XRE	CCK-18LED
描述	LED Lighting Development Tools XP-E Chemical Compatibility Kit	LED Lighting Development Tools XR-E Chemical Compatibility Kit	LED Lighting Development Tools Deluxe Chemical Compatibility Kit
Product Attribute	Attribute Value	Attribute Value	Attribute Value
制造商 Manufacturer	Cree(科瑞)	Cree(科瑞)	Cree(科瑞)
产品种类 Product Category	LED Lighting Development Tools	LED Lighting Development Tools	LED Lighting Development Tools
RoHS	Details	Details	Details
产品 Product	Test Kits	Test Kits	Test Kits
用于 For Use With	XP-E	XR-E	18 LEDs
Description/Function	Chemical compatability kit	Chemical compatability kit	Chemical compatability kit
工厂包装数量 Factory Pack Quantity	10	10	10
Core	XP-E	XR-E	-
工作电源电压 Operating Supply Voltage	18 V	18 V	-
Output Current	700 mA	700 mA	-