Beginning in 1998, after five years, in the LED display branch (China is light association LED display branch) organization effort, the LED display test method "industry standard (hereinafter referred to as the" standards ") is releasing implementation. To help users understand correctly LED display performance index, to regulate the LED display market has the extremely vital significance. In order to better implement standard, put forward the following Suggestions.
1, maximum brightness
The end of last year the industry standard in the discussion for the maximum brightness "this important performance didn't give clear property requirements, it is in GB/T1.2-2002. In the standardization work part 2: standard guidelines standardization technology elements method to determine the content of 5.4.3 "by the supplier determined, the value" mentioned in: "if allow product diversification, the product exists some characteristics of the value may not have to make the regulation (although these characteristics of the performance of the product has a significant impact on the)". Because the LED display the use environment of differ in thousands ways, intensity of illumination (which is commonly spoken in the environment brightness) is different, so "for most complex products, as long as the standard stipulates corresponding test method, by the supplier to provide a performance data (product information) than the standard list of specific performance requirements of the better". These are all accord with international standard, but it also created the competition in the bidding unrealistic one-upmanship, users do not know this and that many of the requirements of the tender "maximum brightness" often far more than the actual needs. Accordingly, the proposal is in order to guide the user correctly understand the LED display "maximum brightness" the performance index, industry is necessary to give a guidance: in some occasions, in the use of different intensity of illumination conditions, the LED display brightness to achieve what value can meet the requirements.
2, as main wavelength error
The main wavelength gezer error index, from "gezer wavelength error" is changed to "gezer main wavelength error", more can explain this indicator is the LED display a what characteristics. The main wavelength is equivalent to the human eye color observed color tonal, is a psychological quantity, color is the attribute of a separated from each other. And the industry standards of performance requirements, literally, the user is impossible to understand it is to reflect the LED display color uniformity index. So, is the guide users to find out what this term and then understand this index? From the point of view of the customer was the first to recognize and understand the LED display, and then presents the user can understand the characteristics of simple? As mentioned in the GB/T1.2-2002 (standardization guide in section 2 standard normative technology elements method to determine the content of product standards on one of the principle that is "performance principle" : "as long as possible, requirements shall be expressed by the performance characteristics, and need not design and describing the characteristics to express, this kind of method to leave room for the largest technology development". "as main wavelength error" is such a design requirements, if by "color uniformity" instead of, will not exist limit what wavelength of LED. For users, as long as you promise LED display color is uniform, without thinking about what you are using technology to realize the development of technology, to leave room for as far as possible big, so to the industry's development greatly beneficial.
3, occupies emptiescompared
As said above "performance" principle "as long as possible, requirements shall be expressed by the performance characteristics, and need not design and describing the characteristics to express, this kind of method to leave room for the largest technology development". We think, "occupies emptiescompared" is a design technology requirements, should not be as the LED display product standards of a performance index; We are all understand, what the user will care about display driver than of empty, they do care about the effect of the display screen, not our technical implementation; We should make the technical barriers, limit the technology of industry of development?
4, refresh frequency
From the "standards of measurement method to see, seem to ignore the user a real concern, it is not very good considering each manufacturer of IC, driving the drive circuit and different way, causing the test difficulties. Such as shenzhen stadium full color of the bidding, the sample test in experts, the index of the test will cause many problems. "Refresh frequency" a frame pictures show the time needed for the start of the screen as a led light source, that is the flashing light source frequency. We can use a similar "light sensor frequency plan" instruments of the display screen directly test light blinking frequency, to reflect the index. We do this test using an oscilloscope measurement of any color LED drive current waveform to determine the "refresh frequency", in white measured during the 200 HZ; At level 3 gray and low gray level, the high frequency 10 KHZ, and with PR-650 spectrometer measurement; No matter in white field, or in 200, 100,, and the gray level such as level 50, by flashing frequency source for all for 200 HZ.
All of the above is only for several LED display characteristics do a simple explanation, and many of the bidding encountered in the "working life", "MTBF," and so on, not a test method can in short time confirmed the LED display is in accordance with the stability, reliability or life requirements; Should not stipulate that these requirements. Producers can make sure, but can not replace the request, it is a business concepts, contract concept, not a technology concepts. Industry association should have a clear about that, this is for the user, producers and the whole industry will be very beneficial. For how to guide the user correctly understand the LED display such a complex system of products, or to industry association to make some more LED display technology BBS, many from set out actually, from the user's perspective of this product, guide users to correctly understand the LED display.
