Foreword
In May 1998, LED display special committees set up by the General Assembly was held in Beijing, we need to put the LED display of the main optical properties of standardized testing methods. After the meeting, all special committees under the proposal, the commission responsible for drafting Co., Ltd. Nanjing phenoprolamine "LED display detection" and has organized a Kunming, Haikou, Nanjing, the Third Session of the serious discussions and solicit opinions from all sides, modified to add, In September 2000 in Xiamen for the second time all the members of the General Assembly, "method" issued to all members to start on a trial basis in order to promote the development of industry norms. On a trial basis in the process of setting up technical groups to accept the Beijing Olympic Committee and other units at the time of the commission, one after another in Beijing in the first body, the body, the Olympic Sports Center Gymnasium, such as Huangshan and multi-block-wide color screen, in the light of the "methods" were detected. In April 2001, held in Hangzhou detection technology seminar to discuss "ways" the situation on a trial basis; by the Ching Chung Xi'an, Beijing and other units on-blue "method" made the implementation of the key speakers. In September that year, at the Beijing International Exhibition large-screen displays, the technology group exhibition of multi-block display was measured at the scene, and demarcation of the Chinese Academy measures have been testing the machines for a variety of equipment than to do right. After the two met in Beijing on the "method" was discussed to amend; at the end of 2002 the Ministry of Information Industry reported. Originally scheduled to be held on 5 and 6 this year, all members of the General Assembly, Publicizing the "methods", but not yet granted China and India, combined with "atypical pneumonia" in the market lifted by the General Assembly malaria, and many members also eager to see as soon as possible "method" , In order to meet the requirements of the general membership of the unit, first "method" to discuss revised draft published in the magazine for your reference.
1 scope
The present standard for LED display of machinery, optical, electrical and other key technical levels of performance, and provides for strict testing methods.
The present standard applicable to all types of LED displays (the display).
2 normative reference document
The following documents through the terms of reference of this standard and become the standard terms. Note the date of any reference document for all subsequent amendments to a single (not including the contents of errata) or revised edition of the standards are not applicable to the present. However, under this part to encourage the parties to reach an agreement to study the possibility of using the latest version of these documents. Note the date of which are not in the documents cited, the latest version of the application of this part.
GB4208-1993 electrical and electronic products, standards protective shell
SJ/T11141-XXXX LED display common norms
Grade 3
Then test results, the indicator will be divided into three grades.
Class A: display should meet the basic indicators.
B grade: A-level than targets.
C grade: A-level than targets and the B-class.
4 testing environment and test instrumentation
4.1 Test Environment
In addition to the special provisions, the test environment are as follows:
Ambient temperature: 15 ℃ ~ 35 ℃;
Relative Humidity: 40% to 80%;
Atmospheric pressure: 86kpa ~ 106kpa;
Power supply: 220V ± 10%, 50Hz ± lHz.
4.2 meters and test software
Color TV signal generator: S / N more than 52dB;
Color Analyzer: Precision than ± 5% (used to measure the brightness,
Color, and other optical properties of similar equipment could be);
Vernier caliper: resolution of 0.02mm;
Protractor: accuracy of 2 °;
Thermometer: accuracy of ± 1 ℃;
Light instrument: accuracy greater than ± 10%;
According to meter: accuracy greater than ± 10%;
Oscilloscope: 100MHz;
Gang Chi: the length of more than 1m;
Plug: Precision than 1/100mm;
Identification of brightness test software;
Gray-scale testing software;
Frame rate testing software.
5 test
5.1 Electrical Properties
5.1.l-for-frame frequency
a) definition
Screen update frequency FHO
b) request
c) Measurement
- Frame rate to start testing the software, and on the screen to open the four regions: A1, A2, A3 and A4. The first picture frame in the region A1 within a show "●", the second frame in the region A2 in screen shows a "■", the third picture frame in the regional A3 with a show "▲", in the fourth frame image in the region within A4 Show a "★". More than four pictures for a group and the fifth frame from the beginning of this law shows that the cycle;
- On the screen test showed that the software, if the display area have four full circle, the frequency of FH-for-frame computer frame rate is equivalent to FF, that is, FH = Fr;
- On the screen test showed that the software, if only to display in the region A1 and A3 in the region are full of graphics, or only in the region A2 and A4 in the region with complete graphics, frame-for-frequency FH frame rate is equivalent to computer Half, that is, FH = FF / 2;
- On the screen test showed that the software, if only to display in any region in the integrity of the graphics, frame-for-frequency FH is equivalent to a quarter of the computer frame rate, that is, FH = Fr / 4;
- On the screen test showed that the software, if the display area has four graphics, but graphics do not have been complete line of pumping out or pumping, the frequency of FH-for-frame on the computer equivalent to half the frame rate, that is, FH = FF / 4;
- Computer oscilloscope to measure frame rate FF, and in accordance with the above test results to calculate the frequency of frame-for-FH;
- According to Table 1, the indicator into the appropriate level.
5.1.2 refresh rate
a) definition
Kinds of data per second screen display by the number of repeat FC
b) request
c) Measurement
- Purchase of the most high-brightness display, the gray-scale transformation for the purchase of a dual-color display for the tomb of color combinations, full color screen is white;
SJ/T11141-XXXX
- To observe any oscilloscope - a pixel color LED driver current waveforms, and detect a drive current wave of the cycle T, then refresh rate FC = 1 / T;
- Table 2, under the appropriate level.
5.1.3 duty cycle
a) definition
In the largest gray-scale brightness level and the largest case, any pixel in the same period a scan of the turn-on time (To) and scanning cycle (Ts) ratio to ZQ said. When ZQ ≥ l, defined as a static drive, ZQ <l, defined as a dynamic drive.
b) request
There are usually driven duty cycle 1 / 32, 1/l6, 1 / 8, 1 / 4, 1 / 2 and 1, and so on.
c) Measurement
- Statistics from a display module driving circuit approach Q;
- A display of a number of modules, as large numbers of X;
- If the color display for a few JC;
- Duty cycle drive ZQ = Q (X × JC).
5.1.4 changes in the rate of load modules
a) definition
Gray's largest and highest brightness level, the module shows the entire two-and local-state of the brightness changes in the rate of BL.
b) according to the requirements of Table 3.
c) Measurement
1) Measurement conditions:
Environmental changes in the illumination rate of less than ± 10%.
Optical probe scope of the acquisition shall be not less than 16 adjacent pixels.
2) Measurement:
In the case of black full-screen, color display analyzer measuring the brightness of the background of the BD;
Module to the 1 / 16 for box unit module will be divided into a number of regions, either as a regional test area;
Modules at the highest brightness level, the highest level and throughout the gray light of the situation of the whole module, measuring the brightness of the module BQ;
Modules will be tested at the highest brightness level, the highest-level gray-scale, but there is only one module in the region-wide, measuring the brightness of the region BB;
Modules with calculated under-brightness changes:
BL = (BB-BQ) / (BB + BQ-2BD) X100%;
Measuring the calculation method used were red, green, blue, yellow, white brightness changes in the rate, whichever is the maximum value modules load rate of change;
Table 3 according to the provisions under the corresponding level.
5.1.5 gray level
a) definition
Screen at the same level of brightness in gray-scale from zero to the highest level between the gray-G.
b) request
G demarcation of the gray level will generally be divided into gray-scale-free (l-bit grayscale technology), 4 (2-bit grayscale technology), 8 (3-bit grayscale technology), 16 (4-bit grayscale Technology), 32 (5-bit gray-scale technology), 64 (6-bit gray-scale technology), 128 (7-bit grayscale technology), 256 (8-bit grayscale technology) level, and so on. In any level, with light gray level monotony was the number should be increased.
c) Measurement
1) Measurement conditions:
Environmental changes in the illumination rate of less than ± 10%;
Throughout the testing process, the color analyzer of the same scope of the collection.
2) The test step
Gray to start testing the software, increase the level gray-scale, with the screen brightness to the gray level monotony was rising up;
Friends of the actual degree of class
1 <G ≤ 2 screen with l-bit grayscale technology;
2 <G ≤ 4 screen with 2-bit grayscale technology;
4 <G ≤ 8 screen with 3-bit gray-scale technology;
8 <G ≤ 16 display with 4-bit grayscale technology;
16 <G ≤ 32 display with 5-bit gray-scale technology;
32 <G ≤ 64 display with 6-bit gray-scale technology;
64 <G ≤ 128 screen with a 7-bit gray-scale technology;
128 <G ≤ 256 display with 8-bit grayscale technology;
And so on.
5.1.6 SNR
a) definition
In the video signal, the signal RMS RMS S and N noise ratio (S / N).
b) according to the requirements of Table 4.
c) Measurement
Strong light of the optical instrument probe of a hooded pixel (to prevent outside interference of light), and thereafter in the process of testing intensity lighting instrument probe the situation remains unchanged;
Will screen at maximum brightness, the largest gray, measured under the light of this situation IEM;
Will screen at maximum brightness level, 50% gray, gray-scale to measure the intensity of the IEH;
Color television signal instrument (signal to noise ratio greater than 52dB), to the control system into the white signal (PAL system); color television signal conditioning instrument took place output range, so that the pixel light intensity equivalent to IEH, and then the state To allow for display and a half hours of work;
Video screen will freeze, a freeze frame after the detection of the pixel light IDi, a total of 20 times to repeat the steps to detect ID1, ID2 ... ID20, to find out which of the three largest IDi, for the arithmetic average IDmax, and then to find out Three of the smallest IDi for the arithmetic average IDmin;
Press-to-noise ratio calculated
S / N = 20lg [2 √ 2IEM / (IDmax-IDmin)];
According to Table 4, under the appropriate level.
5.1.7 pixel rate of loss of control
a) definition
Pixel out of control is divided into two types of blind spots and bright spots often. Full-screen pixel Pz equal to the rate of loss of control of the entire screen with a few blind spots Always point of the whole screen and the number of pixels on the screen as a whole in the previous year. PQ-pixel region out of control rate equal to a few blind spots and regional points of Always on the region and the number of pixels than (referring to the region of 100 × 100 pixel matrix).
b) according to the requirements of Table 5.
c) Measurement
1) the rate of loss of control of the entire screen pixel measurement PZ:
The whole screen showing the gray-scale red, with a number of non-visual light of the number of pixels PF;
Qing Ping, with a few visual method of red pixels Always a few PL;
With under-calculated the rate of red pixels out of control
PTR = (PF + PL) / P;
Where, P for the total number of full-screen pixel (P if less than 10,000, according to calculations 10,000);
Using the same method of calculation may be out of control out of the blue pixel rate of PTB and green pixel out of control rate of PTG;
Check PTR, PTB, PTG as the highest value of the entire screen pixel rate of loss of control PT, in accordance with the requirements of Table 5, into the corresponding level.
2) regional pixel rate of loss of control of the PQ measurement
Software used to be a 100 × 100 pixel removable red box (top-level grayscale);
The mobile blind spot in the red box to find the most populated region of the AP;
Visual method to use a box within a few blind spots in a number of red M;
Qing Ping, with a few visual method AP Always points in the red N;
A red Pixel region out of control equal to the rate of M, N divided by region and the number of pixels (PAR = (M + N) / 10000)
Using the same method to measure the regional rate of PAG green pixel out of control and regional blue pixel rate of loss of control PAB.
Check PTR, PRB, PTG in the region as the highest pixel rate of loss of control PQ, in accordance with the requirements of Table 5, into the corresponding level.
5.2 Optical Properties
5.2.1 maximum brightness
a) definition
Display a certain illumination environment, the highest in the gray level and the highest brightness level measured brightness B.
b) Measurement
1) Measurement conditions:
Environmental changes in the illumination of less than ± 10%;
Measurement of the region should not be less than 16 adjacent pixels.
2) Measurement:
All-black screen, the color analyzer display measuring the brightness of the background of the BD;
Screen brightness at the highest level, the highest-level gray, the color analyzer display measurement of the largest degree of brightness Bmax;
The actual maximum brightness: B = Bmax-BD;
Methods used in the above-mentioned cases, white balance, respectively, on-demand measurement of red, green, blue, yellow, white, and so the greatest brightness.
5.2.2 Perspective
a) definition
The assumption that light-emitting display pixel brightness of the normal direction for the BF, from the left and right display screen brightness detection. When the left and right down to the brightness value of the BF / 2, said two observation angle between the line θS (θS <l80 °) for the display of the horizontal angle. From top to bottom on both sides of the display screen brightness detection, when the brightness up and down both sides of the decline in the value of the BF / 2, said two observation angle between the line θC (θC <180 °) for the display of vertical angle .
b) angle measurement
1) Measurement conditions
Environmental changes in the illumination of less than ± 10%, do not apparent colored light source;
Optical probe scope of the acquisition shall be not less than 16 adjacent pixels;
2) measuring the level of perspective:
Full-screen display shows the highest brightness level, the highest level of a gray color;
Color analyzer measurement box with the direction of the normal brightness of BF;
In order to display center-piece for the center, rotating in the same radius, along the horizontal direction to the right and left sides were turning color analyzer, when the brightness value dropped to BB = BF / 2 when Liangchu observation of the two lines of The angle between θSX;
Liangchu the same way every color of the level of perspective, check the display is the minimum level of perspective θS.
3) vertical angle measurement:
Full-screen display with the highest brightness level and the highest-level grayscale display a certain color;
The remaining steps of the perspective and level of measurement is basically the same, the only color analyzer in a different direction of rotation, if conditions permit, it can rotate the screen to measure the way;
By the same method of measuring the color of each of the vertical angle, the screen is taking the minimum vertical angle θC.
5.2.3 the highest contrast ratio
a) definition
Display some of the environmental illumination, the largest of its brightness with the brightness of the background of more than C.
b) Measurement
1) Measurement conditions:
Indoor display screen surface normal direction for the illumination of 100 × (l ± 10%) LX;
Outdoor display screen surface normal direction of illumination for 10 000 × 1 ± 10%) LX
Measurement of the region should not be less than 16 adjacent pixels.
2) Measurement:
5.2.1 in accordance with the maximum brightness measurements were measured approach Bmax and BD;
Press-based contrast C
C = (Bmax-BD) / BD;.
5.2.4 at the main color Errors
a) definition
The main screen color wavelengths and the actual value of the nominal value of the error △ λD.
b) according to the requirements of Table 6.
c) Measurement
1 measurement conditions:
Environmental changes in illumination than 10LX;
Does not allow the existence of colored light around;
Optical probe scope of the acquisition of not less than 16 adjacent pixels.
2) Measurement:
Color analyzer, respectively measuring red, green, blue and other colors of the color coordinates of the goods;
According to the color of their goods coordinates in the color chart to find out the color of the main wavelength;
Calculated and measured wavelength of the main nominal wavelength of the main difference, which is taking the maximum wavelength of color error △ λD;
Table 6 in accordance with the provisions under the corresponding level.
5.2.5 white color coordinates of the field
a) definition
Three color components of the full color display screen in the white field, CIE1931 corresponds to the color map of X, Y coordinates.
Reference link: http://www.17led.com/LEDdisplay/2008-03/37p3.html
