1 | Energy Efficiency and Renewable Energy eere.energy.gov 

Television Set On Mode 

Automatic Brightness Control 

Testing: Effect of Infrared and 

Neutral Density Filters 

February 2013 

Department of Energy 

Energy Efficiency and 

Renewable Energy 
2 

Research Overview 

• Based on DOE’s Round Robin Test Report1, DOE noticed a 

variation in power consumption when testing automatic 

brightness control (ABC) TVs using the distance test set-up 

compared the adjacent test set-up 

• A possible cause could be Infrared (IR) light leading to more 

rapid ABC sensor saturation 

– DOE research indicated that some TVs may use higher quality ABC 

sensors that filter to visible light only, whereas other TVs may use 

sensors sensitive to IR light 

– Halogen lamps emit light outside of the visible spectrum 

1

 Round Robin Test Report available in Docket #EERE-2010-BT-TP-0026 at regulations.gov. 
3 

Testing Overview 

• Lamp: 980 lumen PAR 30S halogen 

• Test set-up: Distance and Adjacent2

• Measurement: 

– Illuminance meter placed in front of the ABC sensor 

– Measured light wavelength and spectral intensity 

– Measurements made at 12, 35, 50 and 100 lux illuminance values 

– Measurements made with Konica Minolta T-10 Illuminance meter

2

 Round Robin Test Report available in Docket #EERE-2010-BT-TP-0026 at regulations.gov. 
4 

Spectral Analysis 

• The area under each curve represents the amount of light 

emitted by the lamp at that illuminance value 

• The vertical line separates the visible and IR spectrums 

0

50

100

150

200

250

300

350 450 550 650 750 850 950

Spectral Intensity (

μW/nm)

Wavelength (nm)

Distance Test Set-up

100 lux

50 lux

35 lux

12 lux

IR Spectrum (750-1000 nm) 
5 

Spectral Analysis 

• The area under each curve represents the amount of light 

emitted by the lamp at that illuminance value 

• The vertical line separates the visible and IR spectrums 

0

50

100

150

200

250

300

350 450 550 650 750 850 950

Spectral Intensity (

μW/nm

Wavelength (nm)

Adjacent Test Set-up

100 lux

50 lux

35 lux

12 lux

IR Spectrum (750-1000 nm)
6 

IR to Visible Light Ratio 

• The ratio of IR to visible light increased as the lamp 

decreased in illuminance 

Illuminance (lux) Ratio of IR to visible light 

Distance Adjacent 

12 3.5 18

35 3.5 8.5 

50 3.3 7.6 

100 3.1 7.5 
7 

IR Filter Testing 

• DOE conducted additional ABC on mode testing with an IR 

filter to determine the effects on illuminance 

• TVs selected based on saturation values of round robin 

testing3 to determine a range of effects 

– TV 1 (lowest saturation value) 

– TV 5 (highest saturation value) 

• Stabilization – played IEC 62087 dynamic video clip for one 

hour prior to testing 

• Method 

– Tested both Distance and Adjacent test set-ups 

– Filter - Hoya 67 mm ultraviolet (UV) and IR blocking filter to ensure 

only visible light entered the ABC sensor 

3

 Round Robin Test Report available in Docket #EERE-2010-BT-TP-0026 at regulations.gov. 
8 

IR Filter Testing 

• IR filter placement 

– All set-ups ensured no unfiltered light entered the ABC sensor 

• TVs tested at the following illuminance values 

– 3, 10, 12, 35, 50, 75, 100, 300 lux 

• All testing conducted in on mode 

Distance IR test set-up 1 Filter directly in front of the lamp

Distance IR test set-up 2 Filter directly in front of the sensor

Adjacent IR test set-up Filter at the end of the apparatus
9 

IR Filter Test Set-up

Distance IR Test Set-up 1 

Figure not to scale 
10

IR Filter Test Set-up

Distance IR Test Set-up 2 

Figure not to scale 
11

IR Filter Test Setup 

Adjacent IR Test Set-up

Figure not to scale 
12

IR Filter Results 

Illuminance 

(lux) 

TV 1 – Distance IR Set-up

 On Mode Power Consumption (watts) % Difference 

Test set-up 1 

Filter at lamp 

Test set-up 2 

Filter at ABC sensor

3 71.6 71.7 0.22% 

10 75.5 79.5 5.05% 

12 81.6 81.7 0.16% 

35 137.6 139.4 1.28% 

50 153.7 153.8 0.07% 

75 153.5 153.6 0.09% 

100 153.3 153.4 0.08% 

300 153.2 153.4 0.08% 
13

IR Filter Results 

Illuminance 

(lux) 

TV 5 – Distance IR Set-up

On Mode Power Consumption (watts) % Difference 

Test set-up 1 

Filter at lamp 

Test set-up 2 

Filter at ABC sensor

3 27.0 27.0 0.02% 

10 30.9 31.6 2.13% 

12 32.8 33.7 2.50% 

35 39.3 39.0 0.84% 

50 43.0 43.1 0.10% 

75 61.2 59.1 3.59% 

100 61.6 61.5 0.06% 

300 71.5 71.5 0.09% 

Remaining analyses performed using data from Distance IR test set-up 2 
14

TV 1 Results 

Lines connecting data points used only for visual aid and do not indicate any trends or relationships between the data 

60

80

100

120

140

160

180

0 50 100 150 200 250 300

Power (watts)

Illuminance (Lux)

TV 1

Distance test set-up

Adjacent test set-up

Distance IR test set-up 2

Adjacent IR test set-up
15

TV 5 Results 

Lines connecting data points used only for visual aid and do not indicate any trends or relationships between the data 

0

10

20

30

40

50

60

70

80

90

0 50 100 150 200 250 300

Power (watts)

Illuminance (Lux)

TV 5

Distance test set-up

Adjacent test set-up

Distance IR test set-up

Adjacent IR test set-up
16

IR Filter Results 

Illuminance 

(lux) 

% Reduction in Power 

TV 1 

% Reduction in Power 

TV 5 

Distance* Adjacent** Distance* Adjacent**

10 37% 54% 32% 56%

12 38% 54% 33% 55%

35 12% 31% 42% 44%

50 2% 21% 41% 24%

75 2% 2% 20% 19%

100 2% 2% 19% 14%

300 2% 3% 7% 6%

* Reduction in power measured when using Distance test set-up 2 compared to the Distance test set-up with no IR filter 

** Reduction in power measured when using Adjacent test set-up compared to the Adjacent test set-up with no IR filter 

Note: Highlighted cells indicate illuminance values at which the TV is saturated 

• On mode percent difference in power consumption with ABC 

enabled without an IR filter compared to with an IR filter 
17

ND Filter Testing 

• In Working Draft 3 of CEA-2037-A, CEA proposed using 3 lux 

for one of the ABC testing illuminance values 

• CEA proposed two methods for achieving 3 lux 

– Directly measure 3 lux using a high quality illuminance meter 

– Measure 12 lux at the ABC sensor and then place 2 stop neutral 

density (ND) filter in front of the sensor, resulting in 3 lux 
18

ND Filter Testing 

• DOE performed testing using both methods proposed by CEA 

– Directly measure 3 lux using a high quality illuminance meter 

– Measure 12 lux at the ABC sensor and then place 2 stop neutral 

density (ND) filter in front of the sensor, resulting in 3 lux 

• Stabilization 

– Played IEC 62087 dynamic video clip for one hour prior to testing 

• Testing performed 

– On three TVs with ABC – TVs 1, 3, and 54 

– Using the Distance test set-up

– Without an IR filter 

4Round Robin Test Report available in Docket #EERE-2010-BT-TP-0026 at regulations.gov. 
19

ND Filter Test Set-up

• Without ND filter 

– Illuminance set to 3 lux 

– Measured directly using a Konica Minolta T-10 illuminance meter 

• Accuracy of ±2% ± 1 digit 

• With ND filter 

– Illuminance set to 12 lux, measured directly using a Konica Minolta T10 illuminance meter 

– A 67 mm Hoya Pro1 Digital ND4 filter was placed directly in front of 

the ABC sensor 

• Measured power consumption and compared results 
20

ND Filter Test Set-up

Figure not to scale 

Test Set-up without ND Filter 
21

ND Filter Test Set-up

Test Set-up with ND Filter 

Figure not to scale 
22

ND Filter Results 

Test Set-up Power Consumption (watts) @ 3 lux 

TV 1 TV 3 TV 5 

No ND filter 71.6 65.0 34.1 

With ND filter 71.6 64.8 30.9 

Coefficient of 

Variation* 0.04% 0.23% 6.91% 

* Coefficient of Variation (CV) is the ratio of the standard deviation to the mean of a given sample 
23

IR and ND Filter Testing 

DOE repeated its testing using an IR filter 

• Hoya 67 mm UV and IR blocking filter placed directly in front 

of ABC sensor 

• Without ND filter: 

– Illuminance set to 3 lux measured with a Konica Minolta T-10 

illuminance meter 

• With ND filter: 

– Illuminance set to 12 lux measured with a Konica Minolta T-10 

illuminance meter 

– Hoya Pro1 Digital ND4 Filter placed in series with the UV/IR blocking 

filter 

– DOE tested this set-up twice – reversed the order of the filters to 

ensure this had no effect on power consumption 
24

IR and ND Filter Test Set-up 1 

Figure not to scale 

• Test set-up with filters placed at the ABC sensor 

• The ND filter is positioned closer to the lamp 
25

IR and ND Filter Test Set-up 2 

Figure not to scale 

• Test set-up with filters placed at the ABC sensor 

• The IR filter is positioned closer to the lamp 
26

IR and ND Filter Results 

Test Set-up Power Consumption (watts) 

TV 1 TV 3 TV 5 

IR filter Only 71.6 64.9 27.0 

IR/ND Set-up 1 

ND filter closest to lamp 71.3 65.5 26.9 

IR/ND Set-up 2 

IR filter closest to lamp 71.7 64.9 27.1 

CV 0.27% 0.58% 0.41%