AB20-1_技术文档

Application Brief AB20ꢀ1

Using SuperFlux LEDs in

Automotive Signal Lamps

Introduction

Lumileds Lighting SuperFlux LEDs are specifically designed for automotive

signal lamp applications and are designed to operate at high DC forward

currents reliably over the automotive temperature range. Each SuperFlux

LED generates several lumens of luminous flux. In addition, SuperFlux LEDs

have a low thermal resistance package, which reduces the temperature rise

within the LED signal lamp. This allows for higher drive currents and

reduces the loss in optical flux due to selfꢀheating. SuperFlux LEDs allow

the designer to significantly reduce the number of LEDs needed to provide

the required light output.

The colors of SuperFlux LEDs are designed to be compatible with SAE and

ECE color requirements. SuperFlux LEDs are available in an amber color

with dominant wavelengths of 592 and 594 nm. Redꢀorange and red

SuperFlux LEDs are available in three colors with dominant wavelengths of

618, 620, and 630 nm. The redꢀorange color is designed to match the

color of filtered incandescent bulbs.

Index

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Signal Lamp Design Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Estimating the Number of SuperFlux LEDs Needed For a Signal Lamp . . . . . . . . . . . . . . . .5

Calculating the Minimum Number of LEDs Required . . . . . . . . . . . . . . . . . . . . . . . . . . .13

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

SuperFlux LEDs are available in several different optical radiꢀ

ation patterns, which allow the designer to optimize his

secondary optics for different signal lamp designs. Currently,

SuperFlux LEDs are available with round and rectangular

radiation patterns. The round radiation patterns are ideal for

single and multiple row LED arrays (with the same pitch in x

and y dimensions). The rectangular radiation pattern is ideal

for CHMSL applications that require longer aspect ratios

than can be obtained from LEDs with round radiation

patterns. Please refer to the SuperFlux LED Data Sheet for a

current list of available viewing angle options.

SuperFlux LEDs have a lowꢀprofile package, which is

compatible with highꢀvolume automatic insertion equipment.

SuperFlux LEDs are categorized for luminous flux, dominant

wavelength, and forward voltage, which improves the

matching between LEDs within the signal lamp. SuperFlux

LEDs are packaged in tubes with 60 matched LEDs per tube

and shipped in bundles of 1200 matched LEDs, which

simplify the assembly of LED signal lamps.

The Application Note series 1149 has been prepared in order

to simplify the design process using SuperFlux LEDs in autoꢀ

motive signal lamps. This application note series has been

subdivided into the following application notes:

AB20ꢀ1

AB20ꢀ3

AB20ꢀ4

AB20ꢀ5

Using SuperFlux LEDs In Automotive Signal

Lamps

Electrical Design Considerations for SuperFlux

LEDs

Thermal Management Considerations for

SuperFlux LEDs

Secondary Optics Design Considerations for

SuperFlux LEDs

AB20ꢀ6

AB20ꢀ7

Reliability Considerations for SuperFlux LEDs

SuperFlux LED Categories and Labels

These application notes are available from your local

Lumileds Lighting or Agilent Technologies Field Sales

Engineer or from the following URL: www.lumileds.com

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

2

lamp using estimates for these different factors and to iterate

the optical, mechanical, thermal, and electrical designs

based on bench testing of prototype signal lamps.

Signal Lamp Design Process

The design of an LED signal lamp consists of four indeꢀ

pendent but interrelated designs: optical design, mechanical

design, thermal design, and electrical design.

A flow chart of the basic design process for an LED signal

lamp is shown in Figure 1.1 and consists of the following

steps:

The optical design is needed in order to design the secondary

optics elements, such as reflectors or lenses, which are

mounted in front of the LED emitters. In addition, the outer

pillow lens needs to be designed in order to generate the

desired output beam pattern. The optical design of an LED

signal lamp is not unlike that of an incandescent signal lamp,

except that the LED emitters have a much smaller geometry

and a different optical radiation pattern.

1. Define external operating parameters for the signal lamp.

These parameters are usually specified by the car manuꢀ

facturer or defined in various automotive specifications.

These parameters include:

• Operating and storage temperature requirements for

the signal lamp.

• Photometric test conditions of the signal lamp (i.e.,

whether testing is done at initial turnꢀon at room

temperature, after a 30 minute warmꢀup at room

temperature, or over some operating temperature

range).

A mechanical design is needed in order to generate the

desired mechanical drawings for the outer case, outer lens,

and possibly internal secondary optics. The mechanical

design would also include the selection of materials used for

the signal lamp assembly. The mechanical design is not

unlike the mechanical design of an incandescent signal lamp.

• Design voltage (the voltage at which the photometrics

will be tested).

• Operating voltage range (i.e., 9 V to 16 V).

• Transient operating voltage range (i.e., 24 V for 1

minute).

• EMC transients applied to the signal lamp (i.e., SAE

J1113 pulses 1 through 7 and theamplitude and duraꢀ

tion of each pulse).

• Whether any additional photometric guard band is

required above the minimum photometric requireꢀ

ments defined by the SAE or ECE standards.

The purpose of the thermal design is to evaluate the heat

flow from the LED emitters to the ambient air and to reduce

the thermal resistance as much as possible. For best results,

the LED signal lamp should be designed to minimize selfꢀ

heating of the LED emitters. SuperFlux LEDs are limited to a

maximum junction temperature of 125°C. In addition, all

LEDs experience a reduction in light output at elevated

temperatures. This phenomena is fully reversible, such that

the light output returns to its original value when the in the

temperature returns to its initial value. However, selfꢀheating

causes an undesirable reduction in the luminous flux output

of the LEDs. The thermal design of an LED signal lamp

differs from that of an incandescent design. For an incandesꢀ

cent design, the design focus is to choose plastic materials

that can withstand the heat generated by the bulb. For the

LED lamp design, the focus is to protect the LEDs from high

temperatures and to optimize the optical performance.

Please refer to AB20ꢀ6 for a summary of environmental

strife tests that have been used to validate Super Flux

LEDs as well as suggested assembly validation tests for

automotive applications.

The purpose of the electrical design is to choose the approꢀ

priate forward current through the LED emitters and ensure

that this current stays within an acceptable range during

worstꢀcase operation at the extremes of ignition voltage and

temperature. Also, the electrical circuit configuration deterꢀ

mines the luminous intensity matching between the emitters

within the LED signal lamp. In addition, the electrical design

can also protect against EMC transients, and highꢀvoltage

and lowꢀvoltage transient conditions. In many cases, an elecꢀ

trical design is not needed for an incandescent signal lamp

since the bulb can be driven directly from the ignition voltage.

These four design processes are interrelated. For example,

the mechanical drawings used to construct the signal lamp

cannot be completed until the optical, thermal, and electrical

designs are finished. Since these different design processes

are interrelated, it is not uncommon to design the LED signal

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

3

Figure 1.1 LED Signal Lamp Design Process.

2. Determine the SuperFlux LED luminous flux, and forward

voltage categories to be used for the signal lamp.

Category ranges for SuperFlux LEDs are discussed in

AB20ꢀ7. Your local LumiLeds Lighting or Agilent

Technologies Field Sales Engineer should be consulted

to determine which category ranges should be used for

a given model year design.

LEDs Needed For a Signal Lamp contained in this

application note.

7. Pick the circuit topology. Circuit topology refers to the

electronic circuit schematic without the electronic

component values. The key factors of circuit topology for

an LED signal lamp include the following considerations:

• Dimensions of the LED array (i.e., number of strings

of SuperFlux LEDs and how many seriesꢀconnected

SuperFlux LEDs per string).

3. Complete the optical design of the outer lens and

secondary optics (i.e., lens or reflectors mounted over

each LED emitter). AB20ꢀ5 provides some useful guideꢀ

lines on the different options available for secondary

optic designs. Estimate the percentage of optical flux

coupled through the secondary optics and pillow lens

and the percentage of optical flux transmitted through the

outer lens and any other optical surfaces. For a discusꢀ

sion of optical flux losses, please see the following section

of this application note titled Estimating the Number of

SuperFlux LEDs Needed For a Signal Lamp.

• Interconnection scheme for the LED emitters within

the LED array.

• Current limiting method (i.e., resistive or active

current limiting).

• EMC transient protection circuit (if any).

• Dimming circuit (such as for a Stop/Tail signal lamp).

Please refer to AB20ꢀ3 for a detailed discussion of

electrical design considerations.

8. Calculate the nominal values of circuit components [i.e.,

current limiting resistor(s)] using nominal values for the

LED forward voltage. A simple linear model for the

forward voltage of SuperFlux LEDs is given in AB20ꢀ3.

4. Complete the thermal design of the LED signal lamp and

estimate the overall thermal resistance, R , of the

θja

signal lamp. Some useful thermal design guidelines and

a thorough discussion of the measurement techniques

and typical ranges for R

are provided in AB20ꢀ4.

9. Estimate the effects of overꢀvoltage and EMC transients

on maximum forward current through the SuperFlux

LEDs as desired. A discussion of EMC transient protecꢀ

tion circuits is given in AB20ꢀ3.

θja

5. Estimate the maximum DC forward current per SuperFlux

LED based on the overall thermal resistance, R , of the

LED signal lamp, and maximum ambient temperature,

using Figure 4 on the SuperFlux LED Data Sheet.

θja

10. Calculate expected values of luminous flux at 25°C and

over operating temperature as desired. A discussion of

how luminous flux varies over temperature is given in

AB20ꢀ3 and AB20ꢀ4.

6. Estimate the number of SuperFlux LED emitters

needed for the signal lamp. This topic will be covered in

the section titled Estimating the Number of SuperFlux

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

4

11. Complete the electrical design. Perform a worstꢀcase

circuit analysis using worstꢀcase values for the LED

forward voltage to ensure that the maximum forward

current in Step 5 is not exceeded. Worstꢀcase forward

voltage ranges for SuperFlux LEDs are given in AB20ꢀ3.

Note: If the worstꢀcase circuit analysis indicates that the

maximum allowable DC forward current calculated in

Step 5 is exceeded, then Steps 7 through 10 should be

repeated using different assumptions for circuit topology

and nominal forward current.

Estimating the Number of

SuperFlux LEDs Needed For a

Signal Lamp

The number of SuperFlux LEDs needed for a signal lamp can

be easily estimated. This is done by calculating the minimum

luminous flux needed to meet the regulated photometric

minimums, dividing this by the minimum luminous flux

emitted by each SuperFlux LED, and then accounting for all

luminous flux losses in the signal lamp. This process is

summarized in a Microsoft Excel spreadsheet program that

is available from Lumileds. The general calculations that are

used within the spreadsheet are discussed in this section.

These general calculations use a numerical method called

zonal constant integration.

12. Complete the mechanical design and fabricate LED

signal lamp using prototype tooling.

13. Build working prototypes of the LED signal lamp to verify

the electrical circuit design parameters. Prototypes

should be built from different LED categories spanning

the expected forward voltage and luminous flux distribuꢀ

tions. Measure LED forward currents over the expected

range of operating voltages. Measure overall LED signal

In general, the minimum luminous flux emitted by any LED

can be estimated from the onꢀaxis luminous intensity cateꢀ

gory and the viewing angle. For the SuperFlux LED family,

the luminous flux is 100% tested and the LEDs are sorted

into wellꢀdefined luminous flux categories. These categories

are defined in AB20ꢀ7.

lamp thermal resistance, R , using the test procedure

θja

outlined in AB20ꢀ4. Measure the photometric output of

the LED signal lamp at each angular test point in order

to verify the assumptions used in Steps 2 through 6.

Optical measurements should use dataꢀlogged LEDs

and the photometric results should be scaled to the

luminous flux bin minimums given in AB20ꢀ7.

It is also important to consider luminous flux losses within the

LED signal lamp. From experience, these luminous flux

losses are quite large—although not as large as those for an

incandescent signal lamp. The net effect of these luminous

flux losses is that a total of 4 to 10 times more luminous flux

is needed from the SuperFlux LED array than would be

required if the optical system were completely lossꢀless.

Based on the measurements of the prototypes, the

electrical design may need to be further optimized.

A thorough discussion of the effects of different circuit

designs is provided in AB20ꢀ3.

The zonal constant integration technique can be used to

calculate the minimum luminous flux emitted for a given type

of signal lamp. The zonal constant integration technique is a

numerical method where the total luminous flux emitted by

the signal lamp is calculated by summing the amounts of

incremental luminous flux emitted by the signal lamp at

discrete angular positions at all angles where the luminous

intensities are greater than zero. The amount of luminous flux

emitted by each incremental angular position is equal to the

average luminous intensity of each incremental emitting area

multiplied by the solid angle subtended between the speciꢀ

fied incremental emitting area and the adjacent emitting

areas, such as shown in Figure 1.2.

Based on the measurements of the prototypes, the

thermal resistance of the signal lamp may need to be

further optimized. A thorough discussion of the thermal

design factors is provided in AB20ꢀ4.

Based on the measurements of the prototypes, the

optical design may need to be further optimized. A thorꢀ

ough discussion of the optical design of the LED signal

lamps is provided in AB20ꢀ5.

Note: If measurements of the prototype LED signal

lamps indicate that the assumptions for LED forward

For sake of convenience, the radiation pattern of the signal

lamp can be considered to consist of a number of horizontal

bands (i.e., H, 5U, 5D, 10U, 10D, etc.).

voltage, R , and luminous flux utilization are wrong,

θja

then Steps 2 through 12 should be repeated using

measured values or new assumptions based on revised

electrical, thermal, or optical designs.

Then the amount of luminous flux emitted by the signal lamp

into each horizontal band is equal to the summation of the

nonꢀzero luminous intensities of all points in the horizontal

band multiplied by a constant, CZ, called the zonal constant.

The total luminous flux emitted by the signal lamp is equal to

the summation of the amounts of luminous flux emitted by all

of the horizontal bands. Written mathematically, the luminous

flux is equal to:

14. Build additional LED signal lamps using the final elecꢀ

trical, thermal, and optical design. Perform additional

testing to verify the expected ranges for forward current,

thermal resistance, and photometric output. Validate reliꢀ

ability of final design using automotive reliability tests

such as those given in SAE J575, SAE J1889, correꢀ

sponding ECE or other regulations, or AB20ꢀ6.

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

5

As an example of the zonal constant integration technique,

consider the total luminous flux emitted by an automotive

amber rear turn signal (a similar example for an automotive

rear brake lamp is given in Stringfellow, HBLED, pp

246—247). The U.S. requirements for the rear amber turn

signal are contained in SAE J588 titled Turn Signal Lamps

For Use On Motor Vehicles Less Than 2032 mm In Overall

Width. The minimum photometric design guidelines are

shown in Table 1.1. Note that the minimum luminous intensiꢀ

ties are specified over a range of 10 degrees up and down

and 20 degrees left and right.

m / 2

n

⎡

⎤

φ

v

≅

C

z

(

δ

)

I (θ,δ)

V

∑

⎢

⎣

⎥

⎦

all δ horizontal

all θ within

bands with I > 0

horizontal band

V

4

π²

C^z(

δ

)

≅

cos (δ)

nm

Where:

= total luminous flux emitted by the light source

I (θ,δ) = luminous intensity emitted at angular position θ

Φ

v

degrees left/right and δ degrees up/down.

n

= number of horizontal divisions that an imaginary

sphere surrounding the signal lamp is subdivided

into. For example, for 5° increments, n =

360°/5° = 72.

m

δ

= number of vertical divisions that an imaginary

sphere surrounding the signal lamp is subdivided

into. For example, for 5° increments, m =

360°/5° = 72.

= vertical angle of midpoint of horizontal band.

For example, for 5° horizontal bands (i.e., m = 72),

the midpoint of the horizontal band covering

angles from –2.5° to 2.5° would have a value

of δ = 0° and the midpoint of the horizontal band

covering angles from 2.5° to 7.5° would have a

value of δ = 5°.

Since most photometric specifications are specified

in horizontal and vertical increments of 5°, the zonal

constant is equal to:

4

π²

C

z

(

δ

)

=

cos (

δ

,in increments of 5

° )

72²

0.007615cos (

δ

)

Tip: Since most automotive signal lamps are only specified

over a narrow range of up and down angles, typically 15U to

15D, in increments of 5 degrees left and right, then the zonal

constant, C (δ), is approximately equal to 0.0076.

Z

For a detailed derivation of the zonal constant

integration technique, please see G. B. Stringfellow and

M. George Craford, High Brightness Light Emitting Diodes,

pp. 233—246.1

Figure 1.2 Zonal Constant Integration.

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

6

Note that not all luminous intensity points in Table 1.1 are

specified. Therefore, the first step in calculating the minimum

luminous flux is to estimate the luminous intensity values for

the unspecified coordinates (e.g., 5L, 5U and 15L, 10U). A

reasonable assumption is that the luminous intensities of the

unspecified points are equal to the average values of the

luminous intensities of the four adjacent points. Using these

assumptions, the minimum luminous intensities of all of the

unspecified points are shown in Table 1.2. Next the zonal

constant integration is calculated by adding the luminous

intensity values in each horizontal band (e.g., 10U, 5U, etc.)

and multiplying by the zonal constant. Finally, the total lumiꢀ

nous flux of the signal lamp is simply equal to the sum of the

luminous flux values for each horizontal band. For example,

referring to the 10U row of Table 1.2, the luminous flux

emitted within the horizontal band (from 7.5° to 12.5°) is

equal to:

Φ

V

≅ (1+ 10 + 17 + 24 + 26 + 42 + 26 + 24

2

⎛

⎜

⎝

⎞

⎟

⎠

4π

+ 17 + 10 + 1)

cos (10°)

72²

Φ

V

≅ (1+ 10 + 17 + 24 + 26 + 42 + 26 + 24

+ 17 + 10 + 1) (0.00750)

≅ (198) (0.00750) ≅1.48lm

Table 1.1 Minimum photometric design guidelines for a single compartment amber rear turn signal. Alll values in the

table are in candela (cd). Note: Maximum luminous intensity at any point is 750 cd.

220L

10L

5L

V

5R

10R

20R

10U

5U

H

5D

10D

26

15

50

65

50

110

130

110

50

65

50

15

130

26

130

26

15

Table 1.2 Zonal constant integration of minimum photometric design guidelines for a single compartmeent amber

rear turn signal. Note: Parentheses indicate estimated minimum luminous intensity of unspeccified points.

Zonal

Constant

Flux

lm

25L

20L

(1)

15L

(2)

10L

(2)

5L

(3)

V

5R

(3)

10R

(2)

15R

(2)

20R

(1)

25R

Sum

20

15U

10U (1)

(4)

7.36eꢀ3

7.50eꢀ3

7.59eꢀ3

7.62eꢀ3

7.59eꢀ3

7.50eꢀ3

7.36eꢀ3

Total, lm

0.15

1.48

3.49

4.89

3.49

1.48

0.15

15.13

(10)

15

(17)

(30)

(39)

(30)

(17)

(2)

(24)

50

26

(42)

110

130

110

(42)

(4)

26

(24)

50

(17)

(30)

(39)

(30)

(17)

(2)

(10)

15

(1)

(2)

(1)

198

460

642

460

198

20

5U

(1)

(2)

(1)

(79)

130

(79)

26

(79)

130

(79)

26

H

(20)

15

65

(20)

15

5D

10D

15D

50

(10)

(1)

(24)

(2)

(24)

(2)

(10)

(1)

(3)

Using a similar approach, zonal constant integrations for

most commonly used automotive signal lamps were calcuꢀ

lated and are shown in Tables 1.3 and 1.4. The minimum

luminous flux requirements for U.S. signal lamps are shown

in Table 1.3. The minimum luminous flux requirements for

European signal lamps are shown in Table 1.4. The values

shown are based on the minimum photometric guidelines for

single compartment lamps.

SAE J222 Parking Lamps (Front Position Lamps)

SAE J585 Tail Lamps (Rear Position Lamps) For Use

on Motor Vehicles Less Than 2032 mm in

Overall Width

SAE J586 Stop Lamps for Use on Motor Vehicles Less

Than 2032 mm in Overall Width

SAE J588 Turn Signal Lamps for Use on Motor Vehicles

Less Than 2032 mm in Overall Width

SAE J592 Clearance, Side Marker, and Identification Lamps

SAE J914 Side Turn Signal Lamps for Vehicles Less Than

12 m in Length

SAE J1319 Fog Tail Lamp (Rear Fog Light) Systems

SAE J1957 Center High Mounted Stop Lamp Standard for

Vehicles Less Than 2032 mm in Overall Width

SAE J2087 Daytime Running Lamps For Use on Motor

Vehicles

The specifications for U.S. motor vehicle signal lamps are

written by the Society of Automotive Engineers (SAE). These

publications are published in SAE publication HSꢀ34 titled

SAE Ground Vehicle Lighting Standards Manual, which is

updated annually. The primary signal lamp specifications for

passenger cars are as follows:

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

7

Table 1.3 Minimum luminous flux requirements based on the zonal constant integration of different ssingle compartꢀ

ment U.S. automotive signal lamps.

Max I_V

[H, V]

(cd)

Min I_V

[H, V]

(cd)

Min Φ

(lm)

v

Lit Area

2

Function

Signal

U.S. Spec

Color

(cm )

Notes

Front

Turn/Park

Lamp

Turn

SAE J588

Amber

≥ 22

—

200

300

400

500

23.3

33.7

44.2

54.7

Note 1, 2

Position

Park

Not defined

SAE J222

White, Amber

Amber

—

4

0.40

0.21

Note 2

Note 3

Side Turn

Lamp

Turn

SAE J914

200

0.6

Park

Turn

Not defined

SAE J588

Rear

Red

Amber

Red

≥ 37.5

—

300

750

300

18

80

130

80

2

9.5

15.1

9.4

Combination

Stop

Position

Reverse

Rear Fog

Park

SAE J586

SAE J585

SAE J593

SAE J1319

Not defined

Note 4

Red

0.28

15.2

9.0

White

Red

—

500

300

80

—

Note 5

CHMSL

Stop

Day

SAE J1957

SAE J2087

Red

≥ 29

≥ 40

130

25

3.1

Daytime

Running

Lamp

White, Sel

Yellow, Amber

7000

500

39.3

Side Marker

Lamp

Front

Rear

SAE J592

Amber

Red

—

0.62

0.25

0.47

0.19

18

End Outline

Marker Lamp

Front

Rear

SAE J592

Amber

Red

—

0.62

0.25

0.47

0.19

18

Note 1: Minimum luminous intensity requirement is increased if the Front Turn signal (FTS) is mounted in close proximity to Low Beam headlamp

(LB). If spacing from center of the FTS is less than 100 mm from the lit edge of the low beam headlamp, increase minimum IV as follows:

Spacing Between FTS and LB Headlamp

Multiplier

75 mm ≤ spacing < 100 mm

60 mm ≤ spacing < 75 mm

Spacing < 60 mm

1.5

2.0

2.5

Note 2: If the Park signal is combined with the Front Turn signal, at (H, V) the luminous intensity of the Front Turn should be ≥ 5x luminous intenꢀ

sity of the Park signal.

Note 3: Supplemental to Front Turn signal.

Note 4: If the Rear Position signal is combined with the Stop or Turn signal, at (H, V) the luminous intensity of the Stop/Turn signal should be ≥

5x luminous intensity of the Rear Position signal.

Note 5: Installation allows either one Rear Fog lamp on the vehicle centerline or to the left of centerline or two lamps symmetrically placed on

either side of centerline.

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

8

The specifications for European motor vehicle signal lamps

are written by the Economic Commission of Europe (ECE).

Within these regulations, the different signal lamps are further

subdivided into different categories. The primary specificaꢀ

tions and categories for passenger cars are as follows:

ECE Regulation 48 Uniform Provisions Concerning the

Approval of Vehicles with Regard to the

Installation of Lighting and LightꢀSignaling

Devices

ECE Regulation 77Uniform Provisions Concerning the

Approval of Parking Lamps for Powerꢀ

Driven Vehicles

ECE Regulation 6 Uniform Provisions Concerning the

Approval of Direction Indicators for Motor

Vehicles and Their Trailers

ECE Regulation 87 Uniform Provisions Concerning the

Approval of Daytime Running Lamps for

PowerꢀDriven Vehicles

Cat 1: Front Turn signal mounted greater than 40

mm from the headlamp.

Cat 1a: Front Turn signal mounted greater than 20

mm but less than 40 mm from the headꢀ

lamp.

ECE Regulation 91 Uniform Provisions Concerning the

Approval of SideꢀMarker Lamps for

Motor Vehicles and Their Trailers

Cat 1b: Front Turn signal mounted less than 20

mm from the headlamp.

Cat 2a: Rear Turn signal with single level of intenꢀ

sity.

Cat 2b: Rear Turn signal with two levels of intensity

(day and night operation).

Cat 3: Side Turn signal for vehicles without Front

and Rear Turn signals.

Cat 4: Front/Side Turn signal that replaces Front

Turn and is supplemental to the Rear Turn

signal.

Cat 5/6: Supplementary Side Turn signal for vehiꢀ

cles that also have Front and Rear Turn

signals.

ECE Regulation 7 Uniform Provisions Concerning the

Approval of Front and Rear Position (Side)

Lamps, StopꢀLamps and EndꢀOutline

Marker Lamps for Motor Vehicles (Except

Motor Cycles) and Their Trailers

Cat S1: Stop lamp with one level of intensity.

Cat S2: Stop lamp with two levels of intensity (day

and night operation).

Cat S3: Center High Mount Stop lamp

ECE Regulation 23 Uniform Provisions Concerning the

Approval of Reversing Lamps for Powerꢀ

Driven Vehicles and Their Trailers

ECE Regulation 38 Uniform Provisions Concerning the

Approval of Rear Fog Lights for Powerꢀ

Driven Vehicles and Their Trailers

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

9

Table 1.4 Minimum luminous flux requirements based on the zonal constant integration of different ssingle compartꢀ

ment ECE. automotive signal lamps.

.

Max I_V

[H, V]

(cd)

Min I_V

[H, V]

(cd)

Min Φ

(lm)

v

Lit Area

2

Function

Signal

ECE Spec

Color

(cm )

Notes

Front

Turn/Park

Lamp

Turn

Reg 6, Cat 1

Reg 6, Cat 1a

Reg 6, Cat 1b

Amber

—

700

600

860

175

250

400

15.9

22.6

36.3

Note 1

Position

Park

Reg 7

White

—

60

4

2

0.41

0.13

Reg 77

Note 2

Side Turn/Park

Lamp

Turn

Reg 6, Cat 3

Reg 6, Cat 4

Reg 6, Cat 5

Reg 6, Cat 6

Amber

—

700 (front)

200 (rear)

700 (front)

200 (rear)

200

175 (front)

50 (rear)

175 (front)

0.6 (rear)

0.6

13.3

3.9

14.4

0.39

10.3

200

50

Park

Turn

Reg 77

Amber

—

60 (front)

30 (rear)

2

0.13

Note 2

Rear

Combination

Lamp

Reg 6, Cat 2a

Reg 6, Cat 2b

Amber

—

350

700 (day)

50

175 (day)

4.7

15.9 (day)

Stop

Reg 7, Cat S1

Reg 7, Cat S2

Red

—

185

520 (day)

60

130 (day)

5.5

11.8 (day)

Position

Reverse

Reg 7

Red

—

12

4

0.41

15.2

Note 3

Note 2

Reg 23

White

300 (up),

600 (down)

80

Rear Fog

Park

Reg 38

Reg 77

Red

≤ 140 cm²

300

30

150

2

12.4

0.13

—

CHMSL

Stop

Reg 7, Cat S3

Reg 87

Red

—

80

25

3.1

Daytime

Running

Lamp

White

≥ 40 cm²

800

400

37.8

Side Marker

Lamp

Front

Rear

Reg 91, Cat SM1

Reg 91, Cat SM2

Amber

—

25

4

0.6

0.54

0.32

Reg 91, Cat SM1

Reg 91, Cat SM2

Red, Amber

—

25

4

0.6

0.54

0.32

Note 4

End Outline

Marker Lamp

Front

Rear

Reg 7

White

Red

—

60

12

4

0.41

Note 1: Minimum luminous intensity requirement is increased if the Front Turn signal (FTS) is mounted in close proximity to Low Beam headlamp (LB).

ECE Reg 6 Front Direction Indicator

Spacing Between FTS and LB Headlamp

Category 1

Category 1a

Category 1b

spacing ≥ 40 mm

20 mm < spacing < 40 mm

spacing ≤ 20 mm

Note 2: Vehicles should either have two Front Parking lamps and two Rear Parking lamps or one Side Parking lamp on either side. The Front

Park is normally white. The Rear Park is normally red. However, Parking Lamps can be amber if reciprocally combined with the Side Turn

lamps or Side Marker lamps.

Note 3: In the case where a Rear Position lamp is reciprocally combined with a Category S1 Stop lamp, the ratio of luminous intensities (both ON

divided by Rear ON only) should be greater than 5:1. In the case where Rear Position lamp is reciprocally combined with a Category S2

Stop lamp, the ratio of luminous intensities (nightꢀtime S2 Stop ON plus Rear ON, divided by Rear ON only) should be greater than 5:1.

Note 4: The rear Side Markers should emit amber light. However, it can emit red light if reciprocally combined with the Rear Position lamp, End

Outline lamp, Rear Fog lamp or Stop lamp. Rear Side Markers should be amber if they flash with the Rear Turn lamp.

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

10

In order to estimate the number of SuperFlux LED emitters

needed to realize an LED signal lamp, it is important to

account for wasted luminous flux. In addition, the useful

amount of luminous flux emitted by each SuperFlux LED may

be somewhat lower than the luminous flux categories would

indicate. As previously described, these losses may require

the LED array to generate substantially more luminous flux

than indicated by the values in Tables 1.3 and 1.4. For

simplicity, it is possible to create two equations that estimate

the overall flux utilization. The first equation accounts for

luminous flux losses in the outer lens, exterior surfaces (i.e., a

behindꢀtheglass CHMSL), and inaccuracies in the output

radiation pattern. The second equation adjusts the amount

of luminous flux emitted by the SuperFlux LEDs. This equaꢀ

tion accounts for selfꢀheating within the LED array and

luminous flux collection and transmission losses in the

secondary optics.

F

T

= optional photometric guardꢀband.

Note: F ≥ 1

guard

= total luminous flux transmission losses

associated with the output radiation

pattern and outer lens surfaces.

signal

Note: 0 ≤ T

signal

≤ 1

T

L

= optical transmission of the plastic outer

lens.

filler

= optical transmission of the glass window

for behindꢀtheꢀglass CHMSL.

glass

pattern

= luminous flux losses due to radiation

pattern inaccuracy.

The amount of useful luminous flux available from SuperFlux

LEDs may be less than that indicated by the luminous flux

categories. This is because the actual drive current may be

less than the test current used to initially categorize the

LEDs, and the system thermal resistance may also be higher

than the test conditions. SuperFlux LEDs are tested at 70

There are several causes for wasted luminous flux associated

with the outer lens. For example, the radiation pattern

achieved may exceed the minimum luminous intensity values

at some of the points. Or perhaps, the luminous intensity is

greater than zero at points outside the specified range of

angles. Furthermore, the luminous flux values given in Tables

1.3 and 1.4 do not include transmission losses of the outer

lens and transmission losses of the glass window (for a

behindꢀtheꢀglass CHMSL). The optical transmission through

a glass window can be as high as 93%. However, if the rake

angle of the rear window is small, then the Fresnel losses

can be significantly higher. For example, for a rake angle of

20°, the overall transmission through the rear window is

about 65%. Additional transmission losses would occur for a

tinted window. The combined effect of these losses could

result in the minimum lumious flux requirement of a behindꢀ

theꢀglass CHMSL being twice the luminous flux requirement

of an exteriorꢀmounted CHMSL. In addition, the car manuꢀ

facturer may require a guardꢀband of the minimum luminous

intensity values at each angular test point beyond that which

is required to meet the government specification. For these

reasons, the luminous flux needed from the light source is

somewhat higher than the values given in Tables 1.3 and

1.4. The following equations can be used to estimate more

realistic minimum luminous flux values:

mA with a system thermal resistance, R , of 200 ºC/W.

θja

With a higher thermal resistance, some luminous flux will be

lost due to selfꢀheating. Furthermore, most applications

cannot be driven at 70 mA due to the requirements for operꢀ

ation over a range of ignition voltages and at elevated

ambient temperatures. In addition, the secondary optics may

not collect all of the luminous flux generated by the

SuperFlux LEDs. The secondary optics can have transmisꢀ

sion losses as well as limitations on collecting luminous flux

at wider offꢀaxis angles. The following equations can be used

to estimate how much useful luminous flux will be emitted by

the SuperFlux LEDs and collected by the secondary optics

as compared to the published luminous flux category limits:

Φ_LED= Φ

T

(

LED

(

)

cat

+optics

∆Φ

⎛

⎞

⎡

⎤

T_LED

=

Φ

I

f

,

θ

ja

Φ

collected

T

(

)_⎦(

)

( _optics)

+

optics

⎜

⎝

⎟

⎣

∆

T

a

⎠

∆Φ

⎛

⎞

k

T^a

(

−25°C

e⁻

)

Φ_V

T_signal

spec

=

a

Φ_{V realistic}

=

F

guard

⎜

⎟

∆

T

⎝

⎠

Where:

Φ_LED

Φ_cat

= useful luminous flux emitted by the

SuperFlux LED.

= minimum luminous flux emitted per

SuperFlux LED emitter luminous flux cateꢀ

gory

T_signal= T

T

1−L

( )

( _glass)(

)

filler

pattern

Where:

Φ

= realistic luminous flux requirement.

T

_{LED + optics}= total luminous flux transmission losses

associated with the emitter as well as

collection and transmission losses for the

secondary optics.

v realistic

Φ

= minimum luminous flux requirement per

Tables 1.3 or 1.4

v spec

Note: 0 ≤ T_{LED + optics}≤ 1

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

11

∆Φ/ ∆T

= reduction in luminous flux if specification

must be met at elevated temperature.

a

Φ(I , θ ) = normalized luminous flux versus forward

f

ja

current and thermal resistance per Figure

3 of the SuperFlux LED Data Sheet.

Φ

= percentage of luminous flux collected by

secondary optics based on maximum

collection angle of the secondary optics

and Figure 6 of the SuperFlux LED Data

Sheet.

collected

T

k

= optical transmission of secondary optics.

optics

= temperature coefficient: k = 0.00952

for HPWxꢀxH00 SuperFlux LEDs and

0.0111 for HPWAꢀxL00 SuperFlux LEDs.

See AB20ꢀ3 and AB20ꢀ4 for more inforꢀ

mation.

Thus, the number of LEDs, N, needed to generate sufficient

luminous flux required to meet the required photometric

lighting specification is equal to:

⎛

⎜

⎞

⎟

Φ

F_guard

T

⎛

⎜

⎝

⎞

⎟

⎠

⎛

⎜

⎝

⎞

⎟

⎠

v realistic

v spec

N

=

⎜

⎝

Φ_LED

Φ_cat

T

( )(

)

signal

LED +optics

⎠

The approximate numbers of SuperFlux LEDs needed to

meet the SAE and ECE signal lamp requirements are shown

in Tables 1.5 and 1.6. These tables are based on the factor

shown below:

⎛

⎞

F

guard

4 ≤

≤ 8

⎜

⎟

T

(

signal

TLED

+ optics

)(

)

⎝

⎠

Note that for the assumptions used to estimate the number

of SuperFlux LEDs requires that the designer first complete

Steps 1 through 5 of the design process outlined in the

section Signal Lamp Design Process of this application note.

The calculation for the minimum number of SuperFlux LEDs

shown in the sidebar example titled Calculating the Minimum

Number of LEDs Required is Step 6 of this design process.

Once the minimum number of SuperFlux LEDs has been

established, it is possible to complete Step 7 of the design

process—evaluating the circuit topology of the LED signal

lamp.

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

12

collected. Finally, let’s assume that the optical transmission of

the secondary optics is 80%. Then the equations for

Calculating the Minimum Number

of LEDs Required

T

_LED+opticsand (Φ_LED/Φ_cat) are equal to:

Suppose that an LED Rear Stop/Turn signal lamp will be

constructed with 3.0 lumen (Category F) HPWTꢀMH00 and

1.5 lumen (Category C) HPWTꢀML00 SuperFlux LEDs. What

is the minimum number of LED emitters needed?

T_LED+optics= (∆Φ/ ∆T )[Φ(I , θ )](Φ_collected)(T_optics

)

a

f

ja

= (1.00)(0.56)(0.75)(0.80) = 0.34

The minimum luminous flux requirements shown in Table 1.3

are 9.4 lumens for the red Stop lamp and 15.1 lumens for

the amber Rear Turn Signal. Let’s suppose that the signal

lamp needs to operate at 55 ºC and has a system thermal

resistance of 500 ºC/W. Then, for the assumptions listed

Φ_LED

Φ_CAL

=

(T_LED+optics) = 0.34

Thus, the minimum number of LED emitters needed for the

Stop lamp is equal to:

below T

and ( Φ_vrealistic / Φ_v

) are equal to:

spec

signal

T

= 0.9 (red)

filler

⎛

⎜

⎞

⎟

Φ

F

guard

⎛

⎜

⎝

⎞

⎟

⎠

⎛

⎜

⎝

⎞

⎟

⎠

V realistic

V spec

N

=

= 0.8 (amber)

⎜

⎝

Φ_LED

Φ_cat

T

filler

( _signal)( _LED

)

+

optics

⎠

= 1.00 (this application is not a behindꢀtheꢀ

glass CHMSL).

glass

Φ

⎛

⎜

⎝

⎞

⎟

⎠

2.0

0.34

⎛

⎞

V spec

=

⎜

⎝

⎟

⎠

Φ_cat

L

F

= 0.3

pattern

= 1.25

guard

9.4

3.0

⎛

⎞

N

(5.9) = 19

⎜

⎝

⎟

⎠

Thus, the minimum number of LED emitters needed for the

amber Rear Turn signal is equal to:

T

= (T ) (T

= (0.9 for red, 0.8 for amber)(1.00)(1ꢀ 0.3)

) (1 ꢀ L

)

pattern

signal

filler

glass

⎛

⎜

⎞

⎟

Φ

F

guard

⎛

⎜

⎝

⎞

⎟

⎠

⎛

⎜

⎝

⎞

⎟

⎠

= 0.63 for red, 0.56 for amber

V realistic

V spec

signal

N

=

⎜

⎝

Φ_LED

Φ_cat

T

( _signal)( _LED

)

+

optics

⎠

⎛

⎞

Φ_{V realistic}

F

guard

=

⎜

⎝

⎟

⎠

Φ_V

T_signal

spec

Φ

⎛

⎜

⎝

⎞

⎟

⎠

2.2

0.34

⎛

⎞

V spec

=

⎜

⎝

⎟

⎠

Φ_cat

⎛

⎞

1.25

0.63 for red, 0.56 for amber

=

⎜

⎝

⎟

⎠

15.1

1.5

⎛

⎞

N

(6.5)

= 65

⎜

⎝

⎟

⎠

2.0 for red, 2.2 for amber

According to Figure 4b of the SuperFlux LED Data Sheet, the

maximum DC forward current at 55°C, 500°C/W is 50 mA.

Thus, Φ(I , θ ) from Figure 3 of the SuperFlux LED Data

f

ja

Sheet is equal to 0.56. Further, suppose that the signal lamp

needs to meet the SAE J1889 requirement for a 30ꢀminute

warmꢀup prior to taking photometric values. Since Figure 3

of the SuperFlux LED Data Sheet represents the luminous

flux after thermal equilibrium, the 30ꢀminute warmꢀup effects

are included in the 0.56 factor. If the signal lamp does not

need to meet photometrics at an elevated temperature, then

∆Φ/ ∆T is equal to 1.00. Finally, suppose the maximum offꢀ

a

axis angle collected by the secondary optics is 40º. Then,

from Figure 6a of the SuperFlux LED Data Sheet, 75% of the

total luminous flux emitted by the HPWTꢀMH00 will be

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

13

Table 1.5 Approximate number of SuperFlux LEDs for several SAE automotive signal lamps using assumpptions

from this example

.

Signal

SAE Amber

Front Turn

SAE Amber

Rear Turn

SAE Red

Rear Turn

SAE Stop

SAE CHMSL

LED P/N

Φ

= 23.3 lm

Φ

= 15.1 lm

Φ

= 9.5 lm

Φ

= 9.4 lm

Φ

= 3.1 lm

spec

cat, lm

HLMPꢀC100

HPWAꢀM/DH

≈ 0.375

100 to 200

36 to 72

C, 1.5

D, 2.0

26 to 52

20 to 40

26 to 52

20 to 40

9 to 18

7 to 14

HPWTꢀM/DH

E, 2.5

F, 3.0

G, 3.5

H, 4.0

J, 5.0

16 to 32

14 to 26

12 to 24

10 to 20

8 to 16

16 to 32

14 to 26

12 to 24

10 to 20

8 to 16

5 to 10

4 to 8

3 to 6

HLMPꢀDL00

HPWAꢀM/DL

≈ 0.375

248 to 504

160 to 320

A, 0.62

B, 1.0

152 to 304

96 to 192

98 to 196

60 to 120

HPWTꢀM/DL

C, 1.5

D, 2.0

E, 2.5

F, 3.0

64 to 128

48 to 96

40 to 76

32 to 64

40 to 80

30 to 60

24 to 48

20 to 40

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

14

Table 1.6 Approximate number of SuperFlux LEDs for several SAE automotive signal lamps using assumpptions

from this example

.

Signal

ECE Cat S1

Stop

Signal

ECE Rear

Fog

Signal

ECE Cat S3

CHMSL

ECE Cat 1

Front Turn

ECE Cat 2a

Rear Turn

LED P/N

Φ

= 15.9 lm

Φ

= 4.7 lm

Φ

= 5.5 lm

Φ

= 12.4 lm

Φ

= 3.1 lm

spec

cat, lm

HLMPꢀC100

HPWAꢀM/DH

≈ 0.375

60 to 120

132 to 264

36 to 72

C, 1.5

D, 2.0

15 to 30

12 to 24

33 to 66

25 to 50

9 to 18

7 to 14

HPWTꢀM/DH

E, 2.5

F, 3.0

G, 3.5

H, 4.0

J, 5.0

9 to 18

8 to 16

7 to 14

6 to 12

5 to 10

20 to 40

17 to 34

14 to 28

13 to 26

10 to 20

5 to 10

4 to 8

3 to 6

HLMPꢀDL00

HPWAꢀM/DL

≈ 0.375

170 to 340

50 to 100

A, 0.62

B, 1.0

104 to 208

64 to 128

30 to 60

20 to 40

HPWTꢀM/DL

C, 1.5

D, 2.0

E, 2.5

F, 3.0

42 to 84

32 to 64

26 to 52

22 to 44

14 to 28

10 to 20

8 to 16

7 to 14

References

G.B. Stringfellow and M. George Craford, High Brightness Light Emitting Diodes, Semiconductors and Semimetals, Volume 48,

(San Diego, CA: Academic Press, 1997).

SuperFlux LEDs in Automotive Application Brief AB20ꢀ1 (5/04)

15


型号：	AB20-1
厂家：	LUMILEDS LIGHTING COMPANY
描述：	Using SuperFlux LEDs in Automotive Signal Lamps 在汽车方向灯使用的LED食人鱼
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