Resolution LED display key performance indicators

1998 onwards, after five years, the LED display special committee (now the Chinese Optical Society LED display Chapter) organized effort, "LED display test methods" industry standard (hereinafter referred to as the "standard") is about promulgated. To correctly guide the users to understand performance LED display, LED display on the market norm is very important significance.

Order to better implementation of standards, made the following recommendations.

1 maximum brightness

End of last year to discuss the industry "standard", for "maximum brightness," the important performance characteristics did not give specific requirements, which is consistent GB/T1.2-2002s. In the "work of standardization Part 2: technical elements of normative standard method for determining the content" and TDA2822D datasheet and "5.4.3 determined by the value of supply-side" mentioned: "If there is to allow diversification of products, some of the product may not have to make provisions for property value (although the performance of the products of these properties have significant impact). " LED display for use of the environment vary widely, illumination (that is commonly referred to ambient light) not the same, so "for the most complex products, as long as the corresponding provisions of the standard test method, a performance by the supplier to provide data (product information) than the standard list of specific performance requirements are given better. " These are in line with international standards, but it also resulted in unrealistic bids in competition with each other comparisons, the user not know this, resulting in many of the requirements of the tender "maximum intensity" is often far higher than the actual need. It is therefore recommended in order to guide users to correctly understand the LED display of the "maximum brightness," the performance indicators, the industry need to give a guide: in some cases, the use of different illumination conditions, LED displays brightness to what value to meet the requirements.

2 color dominant wavelength error

Wavelength error indicator will be the main color from the "color wavelength error" changed to "color dominant wavelength error" and TDA2822D price and better able to explain this indicator reflects what features LED display. The main color of the human eye is equivalent to the observed wavelength of the color tones, is a psychological quantity, is the distinction between the color of a property. The standard specifies the performance requirements of the industry, literally, the user is unable to understand that it reflects the color uniformity of LED displays an indicator. Therefore, it is to guide the user to figure out the term, and TDA2822D suppliers and then understand the indicators? First, from the customers point of view or to knowledge and understanding of LED display screen, and then gives the user can understand the performance characteristics of easy to understand? As mentioned earlier GB/T1.2-2002 (the work of standardization in Part 2 of normative technical elements of the standard method for determining the content "on product standards developed by one of the principle that" performance principle ":" as long as possible to require performance characteristics should be expressed, rather than to express the design and characterization, this approach to the most left room for technological development "." color dominant wavelength error "is one such design requirements, and if the" color uniformity " Instead, what limit does not exist wavelength LED. For users, as long as you ensure uniform color LED display, and what you do not have to consider technical means to achieve, to the greatest possible technological development leaves room, this of great benefit to the development of the industry.

3 duty cycle

As mentioned above, the "performance principle" "as long as possible, the required performance characteristics should be expressed, rather than to express the design and characterization, this approach to technology development leaves room for the largest." We believe that the "duty cycle" is purely a design technology requirements, LED display products should not be used as a performance standard; everyone is aware, there is what users care about the display driver duty cycle, they care the display effect, and not our technology; why should we create their own barriers to this technology, limiting the industrys technological development?

4 refresh rate

From the "standard" measurement point of view, seem to ignore the genuine concerns of users, it is not well used by all manufacturers take into account the driver IC, drive circuit and in different ways, causing difficulties in the test. For example, full-color screen tender Shenzhen Stadium, in the expert sample test, the test for this indicator has brought many problems. "Refresh" a screen shows the reciprocal of the time required to display as a light source, that is, light flicker frequency. We can use a similar "sense of light frequency meter," the instrument directly to the display of light flicker frequency test to reflect this target. Weve done the test of any oscilloscope measurement of a color LED driver current waveform to determine the "refresh" in the white field measured 200HZ; in three under the low gray level gray scale so that the measured frequency of up to dozen KHZ, but with PR-650 spectrometer measurements; both in the white field, or in the 200,100,50 level gray scale, etc., the source of the flicker frequency meter are 200HZ.

Above points only a few LED display for a simple description of characteristics, there are a lot of experience in bidding, "working life", "mean time to failure" and so on, not a test method LED display in a relatively short period of time confirm whether the stability, reliability or longevity requirements; should not provide these requirements. Producers can make a guarantee, but can not replace the requirement, it is a business concept, the concept of the contract, rather than a technical concept. Industry association which should have a clear view, and this for users, producers and the whole industry will be very beneficial. For proper understanding of how to guide the user of such a complex system LED display products, or to industry associations to build more points LED display technology forums, and more from reality, from a user perspective to analyze the products, LED display to guide users to correctly understand .