【 Weak current College 】 led display test method 】

1 scope
This standard on the led display monitor's mechanical, optical, electrical and other main technical performance ratings, and strictly defines the test method.
This standard is applicable to all kinds of led display (display).
2 normative references files
The following documents to the terms of reference by this standard as the terms of this standard. Where the date of the reference file, it then all modifications list (not including corrigendum) or revision shall not apply to this standard. However, encouraged to reach agreement under this part of the parties on whether or not you can use the latest version of the file. Those who did not note the date of reference file, its latest version applicable to this section.
GB4208-1993 electrician electronics enclosure protection standards
SJ/T11141-XXXXLED display general specifications
3 ratings
Add the test results, the index is divided into three levels.
A-level: display basic indicators to be met.
B-grade: A-level indicators above.
C-level: higher than A level indicators and B-class.
4 test environments and test instruments
4.1 test environment
Except in special, the test environment are as follows:
Ambient temperature: 15 ° c ~ 35 ° c
Relative humidity: 40%-80%;
Atmospheric pressure: 86kpa ~ 106kpa;
Power supply voltage: 220V ± 10%, lHz 50Hz ±.
4.2 test instrumentation and software
Color TV signal generator S/N greater than 52dB;
Color Analyzer: precision is greater than ± 5% (for measurement of luminance,
Chroma and other optical properties of similar instruments also available);
Vernier caliper: resolution 0.02mm;
Protractor: precision 2 °;
Thermometer: accuracy ± 1 ° c;
Light intensity meter: precision is greater than ± 10%;
Lux meter: precision is greater than ± 10%;
Oscilloscope: 100MHz;
Ruler: length greater than 1m;
Plug gauges: precision is greater than 1/100mm
Brightness differential test software;
Grayscale test software;
Frame rate testing software.
5. test method
5.1 electrical properties
5.1.l swap frame frequency
A definition
Screen information update frequency FHO
B) requirements
C measurement
-The start frame rate testing software, and display on four areas: A1, A2, A3 and A4. The first frame in the a1 to display one of the "l", the second frame within the range a2 shows a "*", the third frame in the region to display one A3 "▲", the fourth frame within the region A4 shows a "*". The above four pictures in groups, and from the fifth frame starts according to the law of circular display;
-On the screen displays the test software, to display in the four regions are part of a complete circle, swap frame frequency FH is tantamount to a computer, that is, the frame rate FF FH = Fr;
-On the screen displays the test software, to display only in the a1 and A3 has a full range of graphics, or only in the range a2 and A4 are complete in the area of graphics, swap frame frequency FH is equal to half of the computer frame rate, i.e. the FH = FF/2;
-On the screen displays the test software, to display only in one area there is a complete graphics, swap frame frequency FH is equivalent to one quarter of the computer frame rate, i.e. the FH = Fr/4;
-On the screen displays the test software, to display in the four regions in a graphic, the graphic is not complete by pumping or pumping column, swap frame frequency FH is equal to half of the computer frame rate, i.e. the FH = FF/4;
-Oscilloscope measured FF computer frame rate, and on the basis of the above test results to calculate change frame frequency FH;
-According to table 1 of the index into the appropriate level.
5.1.2 refresh frequency
A definition
The display shows the data per second is the number of repetitions FC
B) requirements
C) measurement
-The most advanced display brightness reset, shades to transform level 1, double-color display for the combination of color, full-color screen is white;
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-Oscilloscope observation ren-pixel color of the LED driving current waveform, and measure a set of driving current waveform period T is the refresh frequency FC = 1/T;
-By table 2, into the appropriate level.
5.1.3 the duty cycle
A definition
In maximum shades and maximum brightness level, any pixel in a scan period breakover time (To) and scan cycle Ts) ratio to ZQ said. When ZQ ≥ 1, defined as static driver, when ZQ "1, defined as dynamic drive.
B requirements
Driver duty usually have 1/32, 1/16, 1/8, 1/4, 1/2 and 1, and so on.
C) measurement
-The statistics display a module of the driver circuit way Q;
-The number of the screen a module like number X;
-To display the base number is JC;
-The driver duty ZQ = Q (X×JC).
5.1.4 module load variation
Define a)
At the highest intensity and maximum brightness level, display modules all bright and local light two of brightness change rate BL.
B) requests by table 3.
C) measurement
Measurement conditions: 1)
Environmental illuminance change rate of less than ± 10%.
Light probe acquisition range shall not be less than 16 adjacent pixels.
Measurement steps: 2)
In full-screen black, with color Analyzer display background brightness BD
To module1/16 square, the module is divided into several zones, select one of the region as a test area;
Module placed the highest brightness level, the highest shades and the entire module is fully lit, measuring the brightness of the module; BQ
Will be the highest measuring module on the brightness level, the highest-gray, but the module is only one area full of bright, measuring the brightness of the region; BB
Use the following formula calculates the rate of change of the brightness of the module:
ＢＬ＝（ＢＢ－ＢＱ）／（ＢＢ＋ＢＱ－２ＢＤ）Ｘ１００％；
Use the method of measurement calculated respectively red, green, blue, yellow and white brightness change rate, for whichthe maximum value is the module load rate of change;
According to table 3 provisions included in the appropriate level.
5.1.5 grayscale
Define a)
Screen at the same level of brightness in gray-scale from zero to maximum grade G between grayscale.
B) requirements
Calibration grayscale G will generally be divided into no grayscale (l-bit grayscale technology), 4 (2-bit grayscale technology), 8 (3-bit grayscale technology), 16 (4-bit grayscale technology), 32 (5-bit grayscale technology), 64-level (6-bit grayscale technology), 128 (7-bit grayscale technology), 256-level (8-bit grayscale technology) level. At any level, the brightness decreases with the number of levels of gray are monotonic increase should be.
C) measurement
Measurement conditions: 1)
Environmental illuminance change rate of less than ± 10%;
Throughout the testing process, color Analyzer acquisition range unchanged.
2) test steps
Start the gray-scale test software, a gradual increase in shades of gray, the display's brightness should rise as grayscale is monotone rose;
The actual level of friends
1 "G ≤ 2 display with l-bit grayscale technology;
2 "G ≤ 4 display technology with 2-bit grayscale;
4 "G ≤ 8 display technology with 3-bit grayscale;
8 "G ≤ 16 display technology with 4-bit grayscale;
16 "G ≤ 32 display technology with 5-bit grayscale;
32 "G ≤ 64 display technology with 6-bit grayscale;
64 "G ≤ 128 display technology with 7-bit grayscale;
128 "G ≤ 256 grayscale display with 8-bit technology;
And so on.
5.1.6 SNR
Define a)
In the video signal, the signal valid values are valid values for N S and noise ratio (S/N).
B) requests by table 4.
C) measurement
Use intensity meter optical probes covering a pixel (to prevent outside interference of light), and the subsequent testing instrument lighting probe light intensity conditions remain unchanged;
Will display on the highest brightness, gamma, measure the intensity of IEM
Will display on the highest brightness level, 50% gray, measured the gray-scale intensity IEH;
Use color TV signal generator (signal to noise ratio greater than 52dB), to the control system into white signal (PAL); adjust color TV signal generator's output amplitude, the allow pixel intensity equal to IEH, then in this State to display continuous working hours;
The video screen freeze, detect screen freeze after the pixel intensity IDi, repeat this step for 20 measured ID1, ID2 ... ID20, find out where the three largest IDi, arithmetic average IDmax, then find out which three minimum of IDi and arithmetic average get IDmin;
Press-to-noise ratio calculated
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According to the requirements of the table 4, into the appropriate level.
5.1.7 pixel out rate
Define a)
Pixel out into the blind spot and always point two categories. Full screen pixel out rate equal to the number of screen of blind spot Pz and exactly rejecting and permanent points of and on the number of screen pixels. PQ regional pixel out rate is equal to the number area on the blind spots of points and the number of regional pixel ratio (range refers to 100 × 100 pixel matrix).
B) requires at table 5.
C) measurement
1 screen pixel is out of rate) PZ measurements:
A screen displays maximum shades of red, with a few out visually method is off the number of pixels; PF
Screen clearing, Visual method number out red always pixel count PL
Use the following formula calculates the red pixel out rate
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In the formula, p is the total number of full screen pixel (P if less than 10 000, 10 000);
Using the same method to calculate out the blue pixel out rate of PTB and green pixels out rate PTG;
By PTR, PTB, the highest value in the PTG identified as full screen pixel out rate PT, and the requirements of the table 5, into the appropriate level.
2) PQ regional pixel out rate measurement
Use software to do a 100 × 100 pixel removable red square (up-to-gray);
Move the Red block out most populated region in the blind spot of the AP;
Use Visual method number out of the box number M within the Red blind spots;
Screen clearing, Visual method number out of the Red AP always points N;
Regional red pixel out rate equal to the sum of the M, N, divided by the number of regional pixel (PAR = (M + N)/10000)
Using the same method to detect areas of green pixel out rate PAG and regional blue pixel out rate PAB.
By PTR, PRB, PTG highest value is evaluated as the PQ regional pixel out rate, and the requirements of the table 5, into the appropriate level.

5.2 optical performance
5.2.1 maximum brightness
Define a)
Display illumination to a certain environment, at the highest shades and the highest brightness levelMeasurement of luminance B below.
B) measurement
1) measurement conditions
Environmental illuminance change less than ¡à 10%
Measurement range of not less than 16 adjacent pixels.
2 measurement procedures:
Display screen is all black, with color Analyzer display BD background brightness;
Display the highest brightness level, the highest grayscale, color Analyzer display's maximum brightness degree Bmax;
The actual maximum brightness: B = Bmax-BD;
Use the above method to white balance, respectively, on-demand measurement of red, green, blue, yellow, white, and maximum brightness.
5.2.2 perspective
Define a)
Assuming normal directions luminous pixel display screen brightness of the display screen for BF, from the left and right side detection display brightness. When the left and right sides of the brightness values down to BF/2, said two observation angle between the line of θ S (S "l80 ° θ) to display the horizontal angle of view. From the display up and down the brightness of the display side detection, when the upper and lower sides of the brightness values down to BF/2, said two observation angle θ line C (180 ° C "θ) to display the vertical angle of view.
B) measurement of the angle of view
1) measurement conditions
Environmental illuminance changes of less than ± 10%, and no obvious coloured light sources;
Light probe acquisition range shall not be less than 16 adjacent pixels;
2) horizontal angle measurement procedures:
Display full-screen display the highest brightness level, the highest shades of a color;
Color Analyzer measurement block normal direction of brightness BF;
To display Center bright blocks as the Centre and in turn RADIUS unchanged, along the horizontal direction to left rotation color Analyzer, respectively, when the brightness is decreased to BB = BF/2 amount out two observation angle between the line of θ S X;
By the same method of out every base level perspective, taking the minimum value for the display's horizontal angle θ S.
The vertical angle of 3): measurement steps
Display full-screen to maximum brightness level and highest grayscale display a base color;
The rest of the steps and methods of measurement of the horizontal angle of view is basically the same, just the color Analyzer of direction of rotation, if conditions permit, or turn the display of measurement;
By the same method for measuring out of each primary color of the vertical angle of view, taking the minimum value for the display of vertical angle θ C.
5.2.3 the highest contrast
Define a)
Display illumination in certain environments, the maximum brightness and background brightness ratio C.
B) measurement
Measurement conditions: 1)
Indoor display screen of the normal direction of illumination is 100 × (1 of ± 10%) LX;
Outdoor led display screen of the normal direction of illumination 10000 × 1 ± 10%) LX
Measurement range of not less than 16 adjacent pixels.
2 measurement procedures:
In accordance with 5.2.1 maximum brightness measurement method to detect Bmax and BD respectively;
Press-calculate contrast Cr>Ｃ＝（Ｂｍａｘ－ＢＤ）／ＢＤ；。
5.2.4 the base main wavelength errors
Define a)
Display the base color dominant wavelength actual and nominal values error △ D λ.
B) requires the table 6.
C) measurement
1 measuring conditions:
Environmental illuminance change less than 10LX;
Do not allow the existence of coloured light sources around;
Light probe acquisition range shall not be less than 16 adjacent pixels.
2 measurement procedures:
Color Analyzer, measurement of red, green, blue, and chromaticity coordinate base;
According to its chromaticity coordinates, color map to find out the base color of main wavelength;
Calculate the actual primary wavelength and nominal primary wavelength of difference, the maximum value is the base color wavelength λ error △; D
According to table 6, into the appropriate level.
5.2.5 white color coordinates
Define a)
With three basic colors-color display of the display white point, CIE1931 chromaticity diagram corresponds to the X, Y coordinates.
B) requires the table 7.
According to the International Commission on illumination (CIE) 1931 chromaticity diagram to color temperature 6500K-9500K-centric gives the white color coordinate range.
C) measurement
Measurement conditions: 1)
Environmental illuminance changes of less than ± 10%, and no clear colored light; light probe acquisition range shall not be less than 16 adjacent pixels.
Measurement steps: 2)
At the highest shades and the highest brightness level, the display shows all white images; use color Analyzer for white color coordinates of measurement;
5.2.6 brightness differential grade
Define a)
The human eye can distinguish between images from the most black to white, the brightness level between BJ.
B) requirements
C) measurement
Measurement conditions: 1)
Illumination indoor screen environment for 100LX ± 10%;
Outdoor screen environment illuminance to l0% 10000LX ±;
Observation of vote for 5 people.
Measurement steps: 2)
Start the brightness differential test software. There are 24-poor vertical stripes, such as grayscale, in which every piece of kin stripe width not less than 24 columns, stripe color is white. Each pressing the "←" key, test strips left 24 columns; each press about "→" button, the test strip 24 columns to the right;
The viewer stands in front of the display is off the screen width of 5 to 8 times the distances;
Pressing the "←" keys or "→" key, making the test card darkest level vertical stripes and display left-aligned. Then, with the number of Visual method to distinguish the human eye stripe number T1, at this point the brightness differential grade T = T1;
To display a frame is not shown with 24 kin stripes, then press the "→"Key, the left vertical stripes test card, the first frame of the stripes test software the rightmost streaks left to move to the left of the display. Then, with the number of Visual method to distinguish the human eye stripe number T2 is brightness differential grade BJ = T1 + (T2-1);
If the display shows two frames is not 24 vertical stripes; then continue pressing the "←" key, the left vertical stripe testing software, so that the second frame stripe test software the rightmost streaks left to move to the left of the display. Then, with the number of Visual method to distinguish the human eye stripe number T3. You brightness differential grade BJ = T1 + (T2-l) + (T3-1). And so on, until all the vertical stripes 24 bars appear;
The 5-bit observation of vote results, get rid of a highest score and a minimum, the intermediate results of the three-digit and 3 removal is the ultimate level of brightness differential;
According to table 8, into the appropriate level.
5.2.7 uniformity
5.2.7.1 pixel intensity uniformity
Define a)
Display special light (or dark) pixel intensity and associated with the pixel area pixel intensity of BPJ consistency. Associated regional designation as follows:
☆☆☆
☆ ★ ☆ ★ Center pixel
☆ ☆ ☆ ☆ Associated pixel
B-table 9).
C) measurement
All measurements are references to pixel normal light intensity measurements;
In full-screen in a random drawing to 20 pixels;
Use light meter to measure out the respectively 20 pixel intensity values, and to elect three brightest pixels and the three darkest pixels, numbered respectively P1, P2, P3, P4, P5 and P6. Their intensity values are I0 (P1), I0 (P2), I0 (P3), I0 (P4), I0 (P5), and I0 (P6);
By definition, use the measured light intensity meter respectively P1 pixels surrounding the associated region pixel intensity I1 (P1), I2 (P1), ... I8 (P1) is calculated with the following type P1 association region pixel intensity uniformity E [P1];
From 8 associated value in the maximum of a P1 pixel intensity uniform value EP1max
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Using the same methods respectively detect P2, P3, P4, P5 and P6 uniformity of light intensity, take three greatest values arithmetic mean; calculate pixel intensity BPJ uniformity;
On each primary color measurement calculated separately and get maximum value for the screen pixel intensity of uniformity, and 9 by table, as the appropriate level.
5.2.7.2 display module brightness uniformity
Define a)
Several display pixel form a structure independent of the smallest unit, known as modules. Associated regional minimum brightness consistency between modules, called module brightness uniformity BMJ. Delimitation and associated regional association regional area of the pixel.
B 10 per table).
C) measurement
1) measurement conditions
Environmental illuminance changes of less than ± 10%
Light probe acquisition range shall not be less than 16 adjacent pixels.
Measurement steps: 2)
In measurement, observation and the angle between the display are unchanged;
In maximum gray, maximum brightness, full-screen display a base color graphics;
In full-screen, use the Visual method to find the 3 Group regional brightness difference of the maximum number of display module, J1, J2 and respectively J3
Color Analyzer out display module J1 brightness value B0 (J1);
5.2.7.1 association under regional definition, use the color Analyzer respectively detect J1 display module associated area displays the brightness values of the module B1 (J1), B2 (J2), ... Ｂ８（Ｊ８）。 With formula (3) calculate the J1 associated region display module brightness uniformity E [J1] max;
Using the same methods respectively detect J2 and J3 display matrix block brightness uniformity EJ2max, EJ3max
Will EJ1max, arithmetic EJ3max EJ2max, on average, that is the color of the screen brightness uniformity module;
In the same way on each primary color measurement calculated separately;
Get maximum value for the brightness of the LCD display module, and BMJ uniformity in table 10, into the appropriate level.
5.2.7.3 module brightness uniformity
Define a)
The number of display module, driver circuit, control circuit and the corresponding structure constitutes a separate display unit, known as modules. The associated area of brightness consistency between modules, called module brightness uniformity BGJ. Delimitation and associated regional association regional area of the pixel.
B) requires the table 11.
C) measurement
Measurement conditions, measurement, calculation, and the display brightness uniformity of measurement modules.
According to the requirements of the table 11, into the appropriate level.

5.3 mechanical properties
5.3.1 shell protection grade
A request according to table 12.
B) shell protection grade test
By GB4208-93. And according to the requirements of the table 12, into different levels.
5.3.2 module assembling accuracy
5.3.2.1 smoothness
A definition
Display any range of toout deviation between the pixel, represented by the symbol P.
B) asked by table 13.
C) measurement
The 1-metre long steel ruleron the side of the screen of the placed on display anywhere with plug gauge measurement ruler side and display screen the largest gap between P and, in accordance with the requirements of the table 13, into the appropriate level.
5.3.2.2 pixel center distance relative deviation
Define a)
Any adjacent pixel center distance between the measured and nominal centre distance of relative error JX.
B) requirements
C) with an accuracy of measurement: universal measuring 0.02mm; then press-and are calculated according to table 14, into different levels. JX ≥/30lgZB/2 type: Jx-pixel center distance relative deviation ZC-ZB measure pixels away from the Center to center distance of nominal pixel.