Application Note

Light Emitting Diode

Nichia NCSxE17A
Discrete Color LEDs

Table of contents
1. Overview ......................................................................................... 2
2. Full-color Luminaires ................................................................. 2
3. Color Options for the Nichia E17A Series LEDs................ 5
4. Features of the Nichia E17A Series LEDs ............................ 6
5. Assembly Precautions ..............................................................16
6. General Cautions/Suggestions for Using the LEDs .......16
7. Summary ......................................................................................16

The Nichia part numbers NCSxE17A, NxSx119B-V1, and NxSx219B-V1 within
this document are merely Nichia’s part numbers for those Nichia products andare not related nor bear resemblance to any other company’s product thatmight bear a trademark.

This document contains tentative information, Nichia may change the contents without notice.
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Application Note
1. Overview
In recent years, color LEDs have started to be used in various types of lighting fixtures in the lighting
industry. Before color LEDs, floodlights and stage lighting luminaires used white halogen lamps and color
filters (i.e. filters that are colored red, green, or blue, etc.) to create colors (see Figure 1). With this method,a color filter was needed for each color to create the required colors. Additionally, two or more luminaires
were required to create intermediate colors. With color LEDs, a single luminaire can create any color1
without external parts and seamlessly change between colors. Color LEDs have greatly expanded therange of color effects far beyond that of conventional lighting fixtures. Color LEDs have various otheradvantages compared to halogen lamps; for example, reducing the size and weight of a luminaire, energy
saving, improving the maintainability of the luminaire due to the long life of the LEDs.
Nichia offers discrete color LEDs2 for general lighting to meet the needs of its customers. One exampleof this is the NCSxE17A3 LEDs (hereinafter referred to as "Nichia E17A Series LEDs"); since this series is

Light Emitting Diodevery small (i.e. 1.7mm × 1.7mm), the size of a luminaire can be further reduced and a uniform color canbe achieved on the illuminated surface. This application note provides the features and the handlingprecautions for Nichia E17A Series LEDs.

White light + Color filters

Luminaire using
color LEDs

Smaller luminaire
using color LEDs

Figure 1. Reference Image of Full-color Luminaires

2. Full-color Luminaires
2.1. Full-color Luminaires Using LEDs
This section provides examples of full-color luminaires that use color LEDs.
2.1.1. Floodlights
Floodlights are used to decoratively illuminate constructions (i.e. abuilding, bridge, etc.) and landscapes (see Figure 2). Floodlights shouldhave high luminous flux and high luminous intensity to illuminate
objects in the distance clearly. With a programmed control, floodlights
can be operated to emit a single-colored light, create tunable/gradientcolors, and/or flash the light, etc. to provide eye-catching illumination.
Figure 2. Example of a Floodlight Illuminatinga Building with a Colored Light
Any color can be created by adjusting the intensities of three or more colors (i.e. usually primary colors). Generally, the additive primary colors are used forgeneral lighting and PC monitors and those are RGB (i.e. red, green, and blue). Regarding how to create required colors, refer to the application note:
Design Considerations for Full-Color Luminaires Using Discrete Color LEDs.
2
The LEDs that emit a single color (i.e. red, blue, etc.); LEDs that emit white light are not included.
3
The character "x" in the part number "NCSxE17A" described herein refers to the color of the emitted light; each color will have a unique character.
1

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Application Note
2.1.2. Stage Lighting Luminaires
Stage lighting luminaires are available in a variety of types (e.g. hanging from the ceiling, floor recessed,etc.) to illuminate the stage from many different directions. The greatest advantage that can be achievedby using LEDs for stage lighting is the installation flexibility of the luminaires; luminaires that use LEDs areeasier to install and they can be installed in a wider variety of locations than traditional luminaires since
the luminaire size and weight can be reduced when using LEDs as the light source.
Additionally, full-color luminaires using LEDs can provide a more even color without casting multiple
shadows on the stage since the required color is created inside the luminaire. For comparison, when using
the traditional method of creating an intermediate color (i.e. overlapping the colors emitted from multiple
luminaires with color filters on the illuminated surface to create a new color), the individual colors may beseen where the colors do not fully overlap (i.e. the outlines of each light).

Light Emitting Diode2.1.3. Other Luminaires that use LEDs
As discussed above, LEDs increase the design flexibility for luminaires. Full-color tuning is now possible
for a wider variety of locations and for various purposes/situations with luminaires that use LEDs. Nichia
expects that full-color luminaires using LEDs will become more widely used in residential homes in the
future.
2.2. How to Change Colors with Full-color Luminaires
In a full-color luminaire, a required color is created by changing the brightness of each primary color (i.e.
RGB); a luminaire needs to be able to control three or more channels simultaneously for full-color tuning4.
This section discusses some of the communication methods generally used to control the brightness andcolors of a luminaire.
2.2.1. Infrared Communication
The infrared communication is mainly used for general lighting for residential homes. A luminaire using
this communication method has an infrared receiving sensor on it. The brightness and colors arecontrolled with an infrared remote controller supplied with the luminaire. With this communication
method, each luminaire needs a corresponding remote controller; therefore, this method is not suitable
for situations where controlling multiple luminaires at once or a more complicated program control (e.g.
automatic timing control) are needed.

4

Generally, three primary colors (i.e. RGB) are used for full-color tuning; these three colors need to be controlled separately.

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Application Note
2.2.2. Digital Addressable Lighting Interface (DALI)DALI is an international standard for digital lighting control that was developed mainly by European
luminaire manufacturers. Since DALI is a standard, DALI compliant products are interoperable between
manufacturers; this applies not only to luminaires, but also when connecting devices like sensors andswitches to a DALI control system.
As shown in Figure 3, one device (i.e. DALI controller) can control up to sixty-four devices (i.e. luminaires).
Each luminaire has its own unique address and it allows for the luminaires to be controlled individually or
arranged into groups (sixteen groups maximum) to be controlled together. In addition, a DALI system isa two-way communication system; it can monitor the state of the luminaires (e.g. on or off), the power
consumed, etc. and control the luminaires automatically based on the feedback provided. This feature
makes DALI suitable to control multiple luminaires in a large-scale lighting system (e.g. office building)Light Emitting Diode

together with a single communication system.
Luminaires (64 Max)

DALI
Controller
PC

Figure 3. Illustrated Image of a DALI Control System
2.2.3. DMX512 and DMX512-A
DMX512 was originally established by the United States Institute for Theatre Technology (USITT) for
controlling stage lighting dimmers and effects. It was revised to be DMX512-A and approved by theAmerican National Standards Institute (ANSI). Since the digital signal transmission method in DMX512
and DMX512-A is simpler than the other standards and the cables used to connect the devices are robust,
it can offer stable communication even in severe environments. The DMX controller and its controlled
devices are connected in a daisy chain; see Figure 4. Up to 512 channels can be used with a single DMX
controller and 8 bits (i.e. 256 levels of control are available) per channel. In addition to dimming the light,
it is also possible to control the devices mechanically (e.g. panning, tilting, etc.). In most applications, oncea starting address is configured for each device, corresponding addresses (i.e. channels) are automaticallyassigned per control.
DMX512 and DMX512-A systems are usually not used for general lighting for residential homes. They arewidely used for full-color luminaires such as floodlights and stage lighting luminaires to provide eyecatching illumination.
It should be noted that the DMX512 system is not a two-way communication system; if a problem (e.g. adata reception failure, an electrical connection failure in a connected device) occurs, the system cannot
detect it and therefore a DMX512 system it is not recommended for safety-critical applications such as afireworks ignition system. Two-way communication is available with DMX512-A (i.e. Remote Device
Management, RDM).

DMX-inDMX-out

DMX Controller

DMX-out

Terminator

512 Channels Max.

Figure 4. Illustrated Image of a DMX512/DMX512-A system
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Application Note
3. Color Options for the Nichia E17A Series LEDs
3.1. Part Numbers and Characteristics of the Nichia E17A Series LEDs
Table 1 shows the characteristics of each LED in the Nichia E17A Series; the white LED is not included.
Figure 5 shows the wavelengths of the Nichia E17A Series LEDs.
Figure 6 shows the chromaticity of the Nichia E17A Series LEDs.
Table 1. Characteristics of the Nichia E17A Series LEDs (i.e. Typical Characteristics at TC=25°C)

Appearance

Emitted
Color

Royal

NCSCE17A

Blue

OutlineDimensions

ForwardVoltage(IF=350m
A)

Luminous
Flux(IF=350m
A)

AbsoluteMax.
RatingCurrent

AbsoluteMax.
Rating
Temp.

(nm)

(mm)

VF(V)

φv(lm)xyIF_max(mA)

TJ_max(˚C)

451

1.7×1.7×0.35

3.0

18

0.157

0.021

700

135

Chromaticity
Coordinates(IF=350mA)

NCSBE17A

Blue

472

1.7×1.7×0.35

3.0

42

0.126

0.078

700

135

NCSEE17A

Azure

486

1.7×1.7×0.35

3.0

132

0.188

0.268

700

135

Green

539

1.7×1.7×0.35

3.0

208

0.252

0.651

550

135

Lime

567

1.7×1.7×0.35

3.0

212

0.414

0.543

700

135

Amber

590

1.7×1.7×0.35

3.0

124

0.567

0.419

700

135

612

1.7×1.7×0.35

3.0

58

0.669

0.328

700

135

618

1.7×1.7×0.35

3.0

31

0.683

0.313

700

135

NCSGE17ANCSAE17A

BrilliantRed
NCSRE17A
Red
1.2
1

NCSEE17A (Azure)
NCSGE17A (Green)

0.6

NCSGE17A (Lime)

0.4
0.2

NCSEE17A (Azure)

0.7

NCSGE17A (Green)

0.6

NCSAE17A (Amber)

NCSGE17A (Lime)
NCSRE17A (Brilliant Red)

0.5

NCSAE17A (Amber)

0.4

NCSRE17A (Brilliant Red)

0.3

NCSRE17A (Red)

0.2

NCSRE17A (Red)

0.1

0
380

480

580

680

Wavelength (nm)Figure 5. Wavelength
5

NCSBE17A (Blue)

0.8

NCSBE17A (Blue)

0.8

NCSCE17A (Royal Blue)

0.9

NCSCE17A (Royal Blue)y

Relative Emission Intensity (a.u.)Light Emitting Diode

Part
Number5

Dominant
Wavelength

780

0

0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
xFigure 6. Chromaticity Coordinates

The 4th character of the part numbers refers to the color of the light as follows: C: blue (royal blue), B: blue, E: bluish green, G: green, A: amber, R: red.

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Application Note
3.2. How the Nichia E17A Series LEDs Create Colors
There are two ways to create a colored light for an LED. One of them is to use an LED chip that emits therequired color. The Nichia NxSx119B-V1 and NxSx219B-V1 Series LEDs6 (hereinafter referred to as "theNichia 19B-V1 Series LEDs") use this method. The other one is to use a colored phosphor with the LED
chip; the phosphor is excited by the light emitted from the chip and emits the required color. The Nichia
E17A Series LEDs use this method. See Figure 7 for examples of the structure of these two LED series.
In the method used for the Nichia 19B-V1 Series LEDs, an LED chip with the wavelength of the required
color is used. Since the required color can be created with the chip itself, these LEDs do not need aphosphor. While the colored light created with this method has a narrower distribution range for the
wavelength and a higher color purity than the light created with a phosphor, the characteristics of the LED
may greatly vary depending on the color of the chip since the structure of the chip is different for eachcolor. This difference in characteristics should be considered when designing the circuit for a color tunable
In the method used for the Nichia E17A Series LEDs, a phosphor that emits the required color is used; thephosphor is excited by the blue LED chip7 to create the required colored light. The difference in thecharacteristics between the colors can be reduced with this method since all of the colors use a blue chip.

Transparent Lens
Red LED Chip

Red Phosphor
Blue LED Chip

A Nichia 19B-V1 Series LED

A Nichia E17A Series LED

Figure 7. How the Nichia 19B-V1/E17A Series LEDs Create a Red Light

4. Features of the Nichia E17A Series LEDs
This section provides the key features of the Nichia E17A Series LEDs.
4.1. High Light Output and Small Emitting Area
The most remarkable feature of the Nichia E17A Series LEDs is its very compact package size. While therated power consumption of both the Nichia E17A and 19B-V1 Series LEDs are the same, more than threetimes as many E17A Series LEDs can fit in the same area (see Figure 8). This allows the E17A Series LEDs
to have a light output per area that is significantly greater than that of the 19B-V1 Series LEDs8.
20mm

20mm

Light Emitting Diodeluminaire; see section 4.2.

The 19B-V1 Series LEDs: 25 LEDs

Mounting Pitch: 0.4mm
The E17A Series LEDs: 81 LEDs

Figure 8. Number of 19B-V1 and E17A Series LEDs that can be Mounted in the Same Area

The "x" in the part numbers NxSx119B-V1 and NxSx219B-V1 provided herein is an arbitrary character; it varies depending on the color of the emitted light.
The blue (i.e. royal blue and blue) LEDs do not use a colored phosphor; the color of the light of these LEDs is the color of the light emitted by the LED chip.
These LEDs have a transparent resin to protect the chip instead of a phosphor.
8
The difference in the light output per area between the Nichia E17A and 19B-V1 series LEDs varies depending on the emitted color.
67This document contains tentative information, Nichia may change the contents without notice.
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Application Note
If the light output required for the chosen luminaire using the E17A Series LEDs is the same as theluminaire using the 19B-V1 Series LEDs, the area of the total emitting surface can be greatly reduced. A
smaller total emitting surface has advantages when optical components (e.g. lens, reflector) are used with
the LEDs in the luminaire. For example, when the light is collimated to produce a parallel light (e.g. afloodlight), the smaller the total emitting surface is, the narrower the beam angle will be (see Figure 9),
and if the beam angle and the luminous intensity required for the luminaire are the same as when using
the Nichia 19B-V1 Series LEDs, the size of the optical components can be reduced.
However, the heat dissipation needs to be taken into consideration when designing the chosen luminaire
using the Nichia E17A Series LEDs since the power dissipation will be in a smaller area compared to the
19B-V1 Series LEDs. Ensure that the absolute maximum rated junction temperature is not exceeded forany of the LEDs in the luminaire; note that the junction temperature of the LEDs mounted in the middle

Light Emitting Diodeof the PCB tends to be higher than the other LEDs.

Total Emitting Surface: Larger

Total Emitting Surface: Smaller

Beam Angle: Wider

Beam Angle: Narrower

Figure 9. Difference in the Beam Angle Depending on the Size of the Total Emitting Surface
4.2. Same Forward Voltage across all Colors
The forward voltage of an LED varies depending on the emitted color of the chip. For example, for the
Nichia 19B-V1 Series LEDs, the forward voltage is significantly different among the part numbers since
this series of LEDs uses different colored chips. This needs to be considered when designing a circuit using
LEDs of different colors.
Figure 10 shows an example of a circuit that has LEDs with different colored chips. The voltage applied toConstant Current Circuit R1 in Circuit 1 is calculated by subtracting the forward voltage of LED 1 from the
input voltage Vin: 4V - 2.5V ＝ 1.5V. If the current of 100mA flows through LED 1, the same amount of
current flows to Constant Current Circuit R1; the electric power consumed in R1 is calculated as 1.5V ×
100mA = 0.15W. These calculations also apply to Circuits 2 and 3: as done for R1, if the current of 100mA
flows to Constant Current Circuits R2 and R3, the electric power consumed in R2 is 0.05W and that in R3
is 0.1W. The power that is consumed in R1, R2, and R3 is the energy that becomes heat, etc. instead ofbeing converted into light; the power loss of the luminaire is calculated as the sum of the consumed
power in R1, R2, and R3: 0.15W + 0.05W + 0.1W = 0.3W.
Next, assume a case where the difference in the forward voltage between the LEDs in the circuit is greater.
If the forward voltage for Circuit 1 is changed from 2.5V to 2.0V, the electric power consumed in R1 will
increase from 0.15W to 0.2W. As a result, the power loss of the luminaire will increase from 0.3W to 0.35W.
This means that the greater the difference in the forward voltage between the LEDs is, the power loss ina circuit with a lower operating voltage will be greater, causing the luminaire efficacy to decrease and theheat generated in Constant Current Circuits to increase.
For the Nichia E17A Series LEDs, the forward voltage of each color is almost the same since all of the LEDs
in this series use a blue chip. This reduces the difference in the voltage among the circuits, a decrease in
the luminaire efficacy, and the heat generation in the circuits.
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Application Note
Circuit 2

Circuit 1

LED2

LED1

1.5V

R1

100mA

0.5V

LED3

3.0V

3.5V

2.5V
Vin
=4V

Circuit 3

R2

1.0V

R3

Figure 10. Example Circuit for a Color Tunable Luminaire
4.3. Temperature Characteristics of Red LEDs

Light Emitting Diode

When the LED temperature (i.e. the junction temperature) is increased, the luminous flux is reduced inmost cases: generally, this reduction in the luminous flux is greater for a red LED chip than LED chips ofanother color. When using an LED that has a red chip there is a concern that the designed value of theluminous flux may not be obtained due to this temperature characteristic, causing color tunable luminairesthat use this type of LED to not create the required colors.
The Nichia E17A Series LEDs use a blue LED chip for all of the colors. Blue LED chips have more stabletemperature characteristics than red chips; using the E17A Series LEDs offers the following advantages forluminaires: the reduction in the luminous flux due to an increase of the junction temperature is smaller,
and the color shift is smaller.
4.4. Optical Effects Caused by Adjacent LEDs
When LEDs are mounted with a small pitch, the light emitted from an LED may interfere with an adjacent
LED resulting in optical effects on both of the LEDs (i.e. a reduction in the luminous flux, color shift, etc.).
This issue is likely to occur especially for the Nichia E17A Series LEDs due to their structure. Refer to Figure
11 for how an adjacent LED may affect the luminous flux/color for the Nichia 19B-V1 Series and E17A
Series LEDs.
For the 19B-V1 Series LEDs, the light emitted from an LED will hit the substrate and/or the chip of an
adjacent LED causing the light to be reflected or absorbed by the adjacent LED. It may result in a reductionin the luminous flux of the LED. However, a color shift may not be as likely to occur since this series ofLEDs does not contain phosphor, which may be excited by an adjacent LED and emit light.
For the E17A Series LEDs, the light emitted from an LED will hit the phosphor layer of an adjacent LED
causing the phosphor to be excited and emit a low light; it may result in a color shift of the luminaire
using these LEDs. Since most types of phosphors are excited by light whose wavelength is shorter thanthat of the color of the light the phosphor emits, the color shift may be more likely to occur when a blue
LED of this series is illuminated. This means the possibility for a color shift to occur will depend on the
combination of LEDs and LED pitch that are used for the luminaire. Nichia performed evaluations on how
much color shift would occur for different mounting conditions. This section provides the evaluation
results.

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Application Note
Reflected/
Absorbed

ExcitedThe Nichia 19B-V1 Series LEDs

The Nichia E17A Series LED

Figure 11. How an Adjacent LED Affects the Luminous Flux/Color
4.4.1. Evaluation Method
Evaluated LEDs:
R: NCSRE17A (Red)
B: NCSCE17A (Royal Blue)
A: NCSAE17A (Amber)
W: NCSWE17A (Cool White, Rank: sm50/R70)
L: NCSLE17A (Warm White, Rank: sm30/R9050)
All combinations using two colors from the above list were evaluated.
LED Pitch:
The evaluated LEDs were mounted with four different pitches between 0.4mm and 1.9mm.
See Table 2.
Table 2. How the Evaluated LEDs were Mounted
LED Pitch
0.9mm

1.4mm

1.9mm

8

9 .5

11

12 .5

: Color No.2

0 .4

11

9 .5

: Color No.1

12 .5

0.4mm

8

Light Emitting Diode

G: NCSGE17A (Green)

0 .9

1 .4

1 .9

Operating Current:
The evaluated LEDs were operated at the sorting current of 350mA in pulse mode9 to reduce the effectof the self-heating of the LEDs on the evaluations.
Evaluation Method:For each evaluated PCB with the evaluated LEDs mounted per condition, only the LEDs of Color No. 1
were illuminated (i.e. the adjacent LEDs of Color No. 2 were not illuminated); the chromaticity wasmeasured with an integrating sphere.

9

For more information on the operation in pulse mode, refer to the applicable specification.

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Application Note
The obtained chromaticity coordinates were compared to the average chromaticity coordinates of theLEDs that were measured before the LEDs were mounted on the PCB to verify the amount of the color
shift.
4.4.2. Evaluation Results
Figures 12-17 show the evaluation results.

0.020

0.020
Color
No.2
G
B
A
W
L

0.010

0.010

0.005

0.000

0.000
0

0.5

1
1.5
LED Pitch (mm)20Figure 12. Color No. 1: Red

1
1.5
LED Pitch (mm)

2

0.020
Color
No.2
R
G
A
W
L

0.010

0.005

Color
No.2

0.015
⊿u'v'

0.015
⊿u'v'

0.5

Figure 13. Color No. 1: Green

0.020

R
G
B
W
L

0.010
0.005
0.000

0.000
0

0.5

1
1.5
LED Pitch (mm)02Figure 14. Color No. 1: Royal Blue

0.5

1
1.5
LED Pitch (mm)2Figure 15. Color No. 1: Amber

0.020

0.020

0.010
0.005
0.000

Color
No.2
R
G
B
A
W

0.015
⊿u'v'

Color
No.2
R
G
B
A
L

0.015

⊿u'v'

Light Emitting Diode

0.005

Color
No.2
R
B
A
W
L

0.015

⊿u'v'

⊿u'v'

0.015

0.010
0.005

0.000

0

0.5

1
1.5
LED Pitch (mm)2Figure 16. Color No. 1: Cool White

0

0.5

1
1.5
LED Pitch (mm)2Figure 17. Color No. 1: Warm WhiteThis document contains tentative information, Nichia may change the contents without notice.
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Application Note
Evaluation Results and Conclusion:‧ When the illuminated LEDs (i.e. Color No. 1) were not royal blue, the color shift that occurred was verysmall.
‧ When the illuminated LEDs were royal blue (see Figure 14), color shift occurred. The amount of thecolor shift depended on the color of the adjacent LEDs (i.e. Color No. 2). The smaller the LED pitch was,the greater the color shift was since the adjacent LEDs received more light from the illuminated LEDs
when these LEDs were mounted with a smaller pitch.
‧ When the illuminated LEDs were royal blue (see Figure 14) and the adjacent LEDs were green, thegreatest color shift occurred among all the color combinations. It is considered that the green light ismore likely to cause a color shift since the green wavelength is close to the peak response wavelengthof the human eye and the green light has a higher luminous flux. Contrary to the green light, the red

Light Emitting Diodelight does not cause a great color shift since its luminous flux is lower.
These results indicate that the color shift is likely to occur when blue LEDs and LEDs of other colors aremounted next to each other. Nichia recommends selecting a color combination that does not cause agreat color shift when mounted next to each other, mounting the LEDs in a greater pitch, etc.
4.5. Color Uniformity on the Illuminated Surface
An LED-based high-power luminaire (e.g. floodlight) uses an optical component (e.g. lens, reflector) for
each of the LEDs. The reason for this is that if the light directivities of all the LEDs are controlled together
using only one optical component, the optical component would be very large since there would be many
LEDs mounted in the luminaire to obtain a high power, resulting in a large emitting surface; the size ofthe luminaire can be reduced by controlling the light directivity of each LED independently. However, thismethod has disadvantages for color-tunable luminaires including that the individual colors may be seenat the outlines of each light since the colors are mixed on the illuminated surface to create a required
color, and the colors emitted from the LEDs that are mounted in the edges of the PCB may not be mixed
in the created color on the illuminated surface and be seen as they are.
With the Nichia E17A Series LEDs, the sizes of the optical component and the luminaire can be reduced
even when the light directivities of all the LEDs are controlled with one optical component since thepackage of the LEDs is very compact resulting in the area of the emitting surface of the luminaire to begreatly reduced. In addition, for the luminaires using this series of LEDs with one optical component, thecolor can be more uniform on the illuminated surface since the colors are mixed on the emitting surface.
Nichia performed evaluations on the color uniformity on the illuminated surface with the E17A Series LEDs
mounted on a PCB with a small pitch to create colored lights, using one reflector to collimate the lights.
This section provides the evaluation results.
✓ Reduced Area of the Emitting Surface✓ Reduced Number of the Components
Traditional Method
for Color Tuning

Color Tuning with Compact LEDs
(e.g. the Nichia E17A series LEDs)

Used in the Luminaire✓ Improved Color Uniformity

Figure 18. Reference Image of Color Tuning using the Nichia E17A Series LEDs

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Application Note
4.5.1. Evaluation Conditions
Evaluated LEDs:
R: NCSRE17A (Red), G: NCSGE17A (Green), B: NCSCE17A (Royal Blue), W: NCSWE17A (Cool White,5000K)
LED Pitch, Configuration, and Color Combination:
The LEDs were mounted with three different configurations and color combinations, and with four
different pitches between 0.4mm and 1.9mm. See Table 3.
Table 3. How the Evaluated LEDs were Mounted
LED Pitch
1.4mm

1.9mm

14 .7

17 .2

19 .7

12 .2

Configuration 3:
R: 10 LEDs
G: 10 LEDs
B: 8 LEDs
W: 9 LEDs

0 .9

0 .4

19 .7
1 .4

1 .9

23 .3

20 .3

17 .3

14 .3

23 .3

23 .3

20 .3

17 .3
0 .4

1 .9

20 .3

17 .3

14 .3

14 .3

R: 13 LEDs
G: 12 LEDs
B: 12 LEDs

1 .4

20 .3

Configuration 2:

0 .9

0 .9

23 .3

0 .4

17 .3

R: 12 LEDs
G: 12 LEDs
B: 12 LEDs

12 .2

Configuration 1:

17 .2

0.9mm

14 .7

0.4mm

14 .3

Light Emitting Diode

Configuration

1 .4

1 .9

Configuration 1: Each of the red (R), green (G), and royal blue (B) LEDs were mounted in a line. This
simple way of mounting the LEDs would make designing the wiring pattern for the PCB easier.
Configuration 2: The red, green, and royal blue LEDs were mounted in a manner where the same color
LEDs were not next to each other.
Configuration 3: The red, green, royal blue, and cool white (W) LEDs were mounted in a manner where
the same color LEDs were not next to each other. Using white LEDs with the red, green, and royal blue
LEDs enhances the expression of pale colors (i.e. pastel colors).

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Application Note
Evaluated Reflector:
A reflector whose half-power beamwidth was approximately 10° was used to achieve a narrow
directivity. Figure 19 shows the approximate outline dimensions of the evaluated reflector.
120mm
75mm
Figure 19. Evaluated Reflector
Created Colors:
Table 4 shows the created colors that were evaluated. The brightness and chromaticity of each createdLight Emitting Diodecolor were controlled to be the same for all the evaluated PCBs by adjusting the current that flowed
through each LED.
Table 4. Created Colors
Configuration

Created Colors
5000K

Configuration
1&2(R, G, and B)

3000K

The red, green, and royal blue LEDs were illuminated toachieve a color temperature of 3000K.

Green (G)Only the green LEDs were illuminated.

Royal Blue (B)Only the royal blue LEDs were illuminated.

Yellow (Y)The red and green LEDs were illuminated.

Magenta (M)The red and royal blue LEDs were illuminated.

Cyan (C)The green and royal blue LEDs were illuminated.

Cool White (W)Only the cool white (5000K) LEDs were illuminated.

Green (G)+ Cool White (W)Royal Blue (B)+ Cool White (W)(R, G, B, and W)

achieve a color temperature of 5000K.

Only the red LEDs were illuminated.

+ Cool White (W)3

The red, green, and royal blue LEDs were illuminated to

Red (R)Red (R)

Configuration

Note

Yellow (Y)+ Cool White (W)Magenta (M)+ Cool White (W)Cyan (C)+ Cool White (W)The red and cool white LEDs were illuminated.
The green and cool white LEDs were illuminated.
The royal blue and cool white LEDs were illuminated.
The red, green, and cool white LEDs were illuminated.
The red, royal blue, and cool white LEDs were illuminated.
The green, royal blue, and cool white LEDs were
illuminated.

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Application Note
Evaluation Method:For each evaluated PCB, the light was emitted on a white wall that is three meters away from the PCB(i.e. the illuminated surface). The color uniformity of each of the created colors (see Table 4) was
evaluated on the illuminated surface.
4.5.2. Evaluation Results
Tables 5-7 show pictures of the illuminated surfaces for Configurations 1-3.
Table 5. Illuminated Surfaces for Configuration 1
5000K

3000K

R

G

B

Y

M

C

B

Y

M

C

0.4mm
12 .2

12 .2

0.9mm
14 .7

14 .7

0 .9

1.4mm
17 .2

17 .2

1 .4

1.9mm
19 .7

19 .7

1 .9

Table 6. Illuminated Surfaces for Configuration 2
5000K

3000K

R

G

0.4mm
14 .3

14 .3

0 .4

0.9mm
17 .3

17 .3

0 .9

1.4mm
20 .3

20 .3

1 .4

1.9mm
23 .3

23 .3

Light Emitting Diode

0 .4

1 .9

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Application Note
Table 7. Illuminated Surfaces for Configuration 3
W

R+W

G+W

B+W

Y+W

M+W

C+W

0.4mm
14 .3

14 .3

0 .4

0.9mm
17 .3

17 .3

0 .9

1.4mm
20 .3

20 .3

1 .4

1.9mm

Light Emitting Diode

23 .3

23 .3

1 .9

Evaluation Results:‧ For Configuration 1 (see Table 5), the colors did not mix well to create a uniform color when different
color LEDs were illuminated. The luminance was also not uniform when only one color group of LEDs
was illuminated.
‧ For Configuration 2 (see Table 6), the color uniformity was much better than Configuration 1. However,the larger the LED pitch was, the worse the color uniformity was.
‧ For Configuration 3 (see Table 7), the luminance was less uniform compared to Configurations 1 and2. The reason is that more LEDs were left unilluminated for Configuration 3 than for Configurations 1
and 2.
The uniformity of the color and luminance can be improved by arranging the LEDs in a manner that
ensures the colors are mixed evenly on the emitting surface (i.e. Configuration 2).
If the LEDs are not mounted in an equal blend of colors (i.e. Configuration 1), the color uniformity will belower since the colors emitted from the LEDs are not mixed well either on the emitting surface or theilluminated surface.
The uniformity of the color and luminance can be improved even more by using a diffuser in addition tothe optimum arrangement of the LEDs described above; with a diffuser, the colors are mixed near theemitting surface to achieve better color and luminance uniformity (see Figure 20). Note that the luminous
flux and luminous intensity may be reduced when using a diffuser.

Without a Diffuser

With a Diffuser

Without a Diffuser

With a Diffuser

Figure 20. Reference Images of the Emission with/without a Diffuser
and Picture of the Emitting Surfaces
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Application Note
5. Assembly Precautions
One of the features of the Nichia E17A Series LEDs is its compact package size; this feature can be utilized
most when the LEDs are mounted with a small pitch to reduce the emitting area as much as possible.
However, Nichia recommends an LED pitch of ≥0.4mm with consideration of various factors including thedimensional tolerances and deviations of the LEDs and other components, tilting/floating of the LED after
reflow soldering, etc. in addition to the placement accuracy of a typical pick-and-place machine (i.e. chip
mounter). If the LEDs are being used in a high-density application, perform a sufficient verification toensure that there are no issues with the chosen conditions/environments before use.
For more information about assembly precautions, refer to the applicable specification and the application
note: Assembly Precautions for the Nichia NCSxE17A or NVSxE21A Series LEDs.

Light Emitting Diode6. General Cautions/Suggestions for Using the LEDs
When designing luminaires using the Nichia E17A Series LEDs, the following must be considered:‧ The absolute maximum rated forward current must not be exceeded for any of the LEDs in theluminaire under any circumstances. Note that the absolute maximum rated forward current may bedifferent depending on the color of the emitted light.
‧ The absolute maximum rated junction temperature must not be exceeded for any of the LEDs in theluminaire under any circumstances. Note that when the LEDs are mounted with a small pitch, thejunction temperature of the LEDs mounted in the middle of the PCB tends to be higher than the otherLEDs since heat will be concentrated in a small area.
‧ Each LED has its own current and temperature characteristics; the measured values of luminous
flux/chromaticity may be different from the designed values when the LEDs are operated in luminaires.
‧ Depending on the design of the luminaire, the color of the light may not be uniform on the illuminatedsurface (i.e. the emitted colors from the LEDs are not mixed and there are different color patches on
the illuminated surface). Perform sufficient verification to ensure that there are no issues with thechosen luminaire before use.

7. Summary
Nichia makes no guarantee that customers will see the same results for their chosen application describedin this application note; sufficient verification must be done prior to use to ensure there are no issues forthe chosen application.

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Application Note

Light Emitting Diode

Disclaimer
This application note is a controlled document of Nichia Corporation (Nichia) published toprovide technical information/data for reference purposes only. By using this applicationnote, the user agrees to the following: This application note has been prepared solely for reference on the subject matters
incorporated within it and Nichia makes no guarantee that customers will see the same
results for their chosen application.
 The information/data contained herein are only typical examples of performances and/or
applications for the product. Nichia does not provide any guarantees or grant any licenseunder or immunity from any intellectual property rights or other rights held by Nichia or
third parties.
 Nichia makes no representation or warranty, express or implied, as to the accuracy,completeness or usefulness of any information contained herein. In addition, Nichia shallnot be liable for any damages or losses arising out of exploiting, using, or downloadingor otherwise this document, or any other acts associated with this document.
 The content of this application note may be changed without any prior or subsequent
notice.
 Copyrights and all other rights regarding the content of this document are reserved by
Nichia or the right holders who have permitted Nichia to use the content. Without priorwritten consent of Nichia, republication, reproduction, and/or redistribution of thecontent of this document in any form or by any means, whether in whole or in part,
including modifications or derivative works hereof, is strictly prohibited.

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NICHIA CORPORATION
http://www.nichia.co.jp

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