Analysis of the Technical Mechanism of Illumination Measurement and Visual Contrast

Qingdao ASIC design studio Huabeier microelectronics high-frequency source business unit

Keywords: illuminance measurement and visual contrast phenomenon visible light invisible light spectrum per watt illuminance value effective pupil lumen lumen multiple
Abstract: The actual illuminance using a digital timer, and generating a measurement visual contrast phenomenon. The technical reasons are caused by the technical characteristics of the digital illuminance meter, the effective pupil dimming lumens (effective visual light effect) relationship, the human visual sensation, etc., and many factors are caused by each other. The technical mechanism is complex and professional and theoretical. Due to space limitations, this article only provides a brief technical analysis from the practical point of view. To guide the correct application.

First, in reality, the contrast between measurement and vision:
A digital illuminometer is a type of light meter used to measure the amount of light flux on an illuminated surface. The physical quantity detected is the luminous flux in units of: lux (Lx), which is the luminous flux received per unit area. The mathematical expression is: E = d å±® / ds (E: illuminance; d å±®: luminous flux; ds: area).
In actual use, in order to compare the illumination of different types of light sources on a certain work surface, the light effect of the light source is compared. A digital illuminometer is usually used to measure the lux (Lx) values ​​of different types of light sources on the work surface. Calculate the source, lux value per watt.
Namely: illuminance per watt: Cd = E / P;
The unit is: lux/watt (Lx/W).
According to the physical definition and conventional thinking of the digital illuminance meter, it should be a light source with a high lux (Lx) value, a human visual sense is bright; a light source with a low lux (Lx) value, the human visual sense is not bright.
However, in reality, there is a phenomenon of measurement and visual contrast. Namely: The lux (Lx) high-value source, the human visual sense, is not bright; the lux (Lx) low-light source, the human visual sense, but bright.
This kind of measurement and visual contrast phenomenon, the most obvious performance is: T8 straight tube type fluorescent lamp, high pressure mercury lamp, high pressure sodium lamp three light sources, and three primary color high frequency high power industrial and commercial energy saving lamps. High-pressure mercury lamps, high-pressure sodium lamps, and three-color high-frequency high-power industrial and commercial energy-saving lamps, contrast is particularly prominent.

Second, the technical reasons for the measurement and visual contrast phenomenon:
In order to explain more intuitively, the technical reasons for measurement and visual contrast are generated. This paper chooses one, using three-color high-frequency high-power industrial and commercial special energy-saving lamps instead of T8 straight tube fluorescent lamps. The actual measured value of the actual case is explained.
(A), the actual case interpretation:
Qingdao Shunjie Electromechanical Company Office,
Replace the T 8 straight tube fluorescent lamp with the three primary color high frequency and high power industrial special energy saving lamp. [Office] Ground illumination data test record report Tester: Han Yurong
1. Location: One of the offices of Qingdao Shunjie Electromechanical Company. 8 m long * 6 m wide = 48 m 2 , acoustic panel ceiling, 3.5 m vertical.
2, the original light source: embedded grille lamp holder, a set of three 18 W inductive T 8 straight tube fluorescent lamps, a total of 6 groups are evenly arranged.
The original light source consumes electric power and consumes electric power per group = [ 18 W *3 ] + [ 18 W *3*20% ]
=54 W +10.8 W
=64.8 W
Total power consumption = 64.8 W *6
=388.8 W.
The power consumption of the ballast accounts for 20% - 30% of the lamp power, which is 20%, ie: 18 W *3*20%.
3, new light source:
Huabel series three-color high-frequency high-power industrial special energy-saving lamps (hereinafter referred to as high-frequency energy-saving lamps), two 120 models, each actual custom power of 55 W. Replace the original 6 sets of T8 straight tube fluorescent lamps, and the ceiling is evenly installed. A 14-inch deep-light shade is installed, which is 3.3 meters above the ground.
High frequency energy saving lamp total power consumption = 55 W * 2 = 110 W·
4, after the replacement power saving effect:
(1), save electric power = total light source total power consumption 388.8 W
— High-frequency energy-saving lamps consume a total of 110 W of electric power
=278.8 W.
u After replacement, high-frequency energy-saving lamps, power consumption only accounts for =10 W /388.8 W *100 % of the original T 8 straight tube fluorescent lamp
=28.3 %.
u Substitute power saving rate = saving electric power 278.8 W / original light source total power consumption 388.8 W
*100%
= 71.7 %.
(2), saving energy and electricity: every day, according to the lights on for 24 hours, the comprehensive electricity price per kilowatt is 0.8 yuan for calculation.
a, the original light source consumes energy every day = the original light source consumes a total of 388.8W
* Turn on time 24 hours = 9.3312 degrees (KWH).
b. High-frequency energy-saving lamps consume energy every day = high-frequency energy-saving lamps electric power 110 W
* Turn on time 24 hours = 2.64 degrees (KWH)
c, save energy every day = original light source consumes 9.3312 degrees (KWH) per day
— High-frequency energy-saving lamps consume 2.64 degrees (KWH) per day
=6.69 degrees (KWH).
d, save electricity every day = save energy 6.69 degrees (KWH) per day
* The comprehensive electricity price is 0.8 yuan = 5.352 yuan.
e. Monthly electricity saving = daily electricity saving 5.352 yuan * 30 days = 160.56 yuan.
f. Annual electricity savings = monthly electricity savings of 160.56 yuan * 12 months = 1926.72 yuan.
5, after the replacement of the investment recovery period and the first year of pure electricity benefits:
Three primary color high frequency and high power industrial special energy saving lamps, 120 type with 4% VAT, each 180 yuan, two total = 180 yuan * 2 = 360 yuan.
u After the replacement, the payback period = the cost of purchasing high-frequency energy-saving lamps is 360 yuan / the annual electricity savings is 5.352 yuan = 67.2 days.
u The first year of electricity saving pure benefit = annual electricity saving 1926.72
— The cost of purchasing high-frequency energy-saving lamps is 360 yuan = 1566.72 yuan.
6. Measurement and evaluation of lighting effects after replacement:
The ground illuminance value measurement before and after the replacement is measured by a digital illuminometer. The stroboscopic effect is detected by a dedicated detection snail. The color rendering performance is visually compared using colored fabrics and pictures.
(1), after replacement illuminance measurement:
Select three points on the ground evenly, and turn on the T 8 straight tube fluorescent lamp and high frequency energy saving lamp for 5 minutes, then let them reach the optimal ignition state respectively. After that, turn off and turn on and measure separately. Ground illuminance measured value, see the table below for the measured value

(2) Substitute illuminance evaluation: From the ground illuminance value, the average illuminance of the high-frequency energy-saving lamps is lower than the average illuminance of the T 8 straight tube fluorescent lamps by 10Lx. However, in the actual scene, the human visual sense is still high-frequency energy-saving lamps, which are obviously brighter than the T 8 straight tube fluorescent lamps.
(3), after the replacement of lighting quality evaluation: mainly for the evaluation of the stroboscopic effect and color rendering performance of the electric light source, the evaluation content and evaluation value list are as follows

From the above table, we can see that the three primary color high frequency and high power industrial special energy saving lamps replace the T8 straight tube fluorescent lamps. The power saving rate is as high as 71.7%. No stroboscopic effect, the color rendering performance is increased by 2 times, close to the sun color. Watch the colorful fabrics without color cast and the colors are vivid. The lighting environment is bright and comfortable, which helps to improve work efficiency.
(2) Analysis of the technical mechanism that causes measurement and visual contrast:
First, the light spectrum emitted by the T 8 straight tube fluorescent lamp is wider than that of the high frequency energy saving lamp. Including part of the invisible light spectrum, the effective pupil lumen lumen multiple (effective visual efficacy) is low.
The second is the three-color high-frequency high-power industrial special energy-saving lamps, the light spectrum emitted. Most of them are concentrated in the optical spectrum of visible light, and the spectrum of invisible light is small. Inger, three-color high-frequency high-power industrial special energy-saving lamps, effective pupil dimming multiple (effective visual light effect) high.
Third, the digital illuminometer, the measured light energy, is the light energy of all the light spectrum emitted by the light source. Human vision can only sense the light energy in the visible spectrum of the light spectrum. The light energy of the invisible spectrum is not perceptible to human vision.
Fourth, due to the light source containing the invisible spectrum of light energy, stroboscopic effect, color rendering performance and other factors. T 8 straight tube fluorescent lamp effective pupil lumen lumen multiple (effective visual light effect), lower than the high frequency energy saving lamp effective pupil lumen lumen multiple (effective visual light effect). Therefore, the effective illumination, T 8 straight tube fluorescent lamp is also lower than the high frequency energy saving lamp.
It is precisely because of the above four technical reasons that the illuminance value of the T 8 straight tube fluorescent lamp is measured by the digital illuminance meter, which is higher than the illuminance value of the three primary color high frequency high power industrial special energy saving lamp. However, the actual ground illumination, T 8 straight tube fluorescent lamps, no high frequency energy saving lamps are bright, such a fact.
The meaning of the physical concept of effective pupil lumen lumen multiple (effective visual light effect), see the article "Scientific selection of high-power energy-saving lamps to construct the basic concept of green lighting environment".

Third, the technical division of measurement and visual contrast phenomenon conclusion:
Through the above technical analysis, it is known that the digital illuminance meter is used to measure the level of the lux (Lx) to compare and determine the luminous efficacy of the electric light source.
u can only be in the same kind of light source, in the same environment. Measurements are taken at the same location using the same luminaire. Calculate the light source, the lux value per watt,
Namely: illuminance value per watt: Cd = E / P; (unit: Lx / W).
Where: E: ground illuminance value, the unit is lux Lx
P: electric light source power, the unit is watt W
Cd: illuminance per watt in lux/watt (Lx/W)
On this basis, comparative discrimination can be used to draw scientific conclusions.
The higher the illuminance value Cd per watt of the electric light source, the higher the light efficiency of the electric light source, and the more energy is saved.
u For different types of electric light sources, the influence of the electric light source and the effective pupil dimming multiple (effective visual light effect) should be fully considered. Comprehensive power estimation is performed between the power ratios of different types of electric light sources and each other.
For technical parameters, see <Green Light Source Basic Concept>, <U-tube spiral tube energy-saving lamp application design scheme>, <T5 energy-saving lamp direct replacement T8 fluorescent lamp application design scheme> and other special literatures

Han Yurong Tel 0532 - 8760630 1360 630 6833

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