LED display screen commissioned testing must be conducted in accordance with industry standards. The main testing standards include SJ/T11141-2017, SJ/T11281-2017, T/COEMA 101S-2017, and SJ/T 11292-2016. Test items cover core indicators such as optical performance, electrical performance, structural accuracy, and safety requirements. The following is a detailed explanation of the test items and test report processing procedures for each standard:
I. Main LED Display Screen Testing Standards and Items
1. SJ/T11141-2017 Standard Test Items
Assembly Accuracy: Detects physical splicing errors between display screen modules to ensure a flat and misaligned display image.
Functional Characteristics: Verifies the basic functions of the display screen, such as brightness adjustment, color mode switching, and signal input compatibility.
Maximum Brightness: Measures the highest brightness value of the display screen under full white field conditions, in cd/m².
Viewing Angle: Evaluates the horizontal and vertical viewing angle range to ensure color and brightness consistency at different angles. Brightness Uniformity: Detects brightness differences across different areas of the display screen, usually expressed as a percentage.
Primary Color Wavelength Error: Measures the deviation of the primary wavelengths of red, green, and blue primary colors to ensure color accuracy.
White Scale Color Coordinates: Verifies the color coordinate values (e.g., x, y coordinates) of the white scale color temperature, ensuring they conform to the standard color gamut.
Brightness Discrimination Level: Tests the smallest brightness difference level that the human eye can distinguish, reflecting grayscale performance capabilities.
Maximum Contrast Ratio: Measures the ratio of full black to full white brightness, evaluating the image's depth and detail.
Grayscale Level: Detects the number of grayscale levels the display screen can display (e.g., 8-bit, 10-bit), affecting the smoothness of color transitions.
Frame Rate: Evaluates the frame switching speed of the display screen when processing dynamic images, measured in Hz.
Refresh Rate: Measures the number of times the screen refreshes per second to prevent flickering.
Pixel Failure Rate: Statistically calculates the proportion of uncontrolled pixels (constantly bright, constantly dark, or color-shifted) out of the total pixels, typically requiring ≤0.0001%. Safety-related items: Includes power supply stability, grounding resistance, leakage current to ground, dielectric strength, and temperature rise testing.
Electromagnetic compatibility: Tests interference characteristics (such as radiated interference) and immunity (such as electrostatic discharge and surge immunity).
2. SJ/T11281-2017 standard test items: Covers the core items of SJ/T11141-2017 (such as assembly accuracy, brightness, contrast ratio, etc.), and adds the following: Uniformity: Comprehensively evaluates the overall uniformity of brightness and color.
Signal processing depth: Tests the display screen's bit depth processing capability for input signals (such as 10-bit, 12-bit).
Automatic brightness adjustment: Verifies the display screen's function of automatically adjusting brightness according to ambient light.
3. T/COEMA 101S-2017 standard (small-pitch LED display) test items: Special requirements for small-pitch products (dot pitch ≤ 2.5mm): Non-uniformity test: Includes brightness/color uniformity under maximum brightness, low brightness, and black screen conditions.
Low brightness, high grayscale, high refresh rate: Evaluates grayscale performance and refresh stability in low-brightness environments.
Coupling effect: Detects optical/electrical interference between modules when multiple screens are spliced.
Viewing angle distribution: Refines color shift and brightness attenuation tests for horizontal/vertical viewing angles.
4. SJ/T 11292-2016 Standard (Computer Monitors) Test Items
Applicable to LED-backlit LCD monitors and similar products:
Power supply adaptability: Tests operational stability under different voltages/frequency.
Color consistency: Evaluates the uniformity of color reproduction in different areas of the screen.
Color gamut coverage: Measures the color gamut range (e.g., sRGB, NTSC) that the display screen can cover.
Energy efficiency rating: Detects power consumption per unit area, meeting energy-saving standards.
Electromagnetic compatibility: Includes radio interference and harmonic current testing.
II. Required Documents for Display Screen Test Report
Application form: Provided by the testing organization, requiring basic information such as product model and specifications.
Product sample: Requires a fully functional display screen and its supporting controller, power supply, etc.
Product manual: Includes technical parameters, installation guidelines, and safety precautions. III. Display Screen Test Report Processing Procedure
Application Submission: Fill out the testing application form and submit it to the testing organization.
Confirmation and Negotiation: Confirm the testing items, standards, fees, and cycle time with the organization (usually 5-7 working days).
Sample Submission: Send the samples and documents to the laboratory.
Testing: The laboratory conducts full-item testing according to the standards.
Report Issuance: After the test is passed, an electronic report is provided for the client's verification.
Report Delivery: After confirmation, a paper or electronic version of the official report is sent.
IV. Testing Cycle and Precautions
Normal Cycle: 5-7 working days (starting from the date of confirmation of sample and document accuracy).
Key Requirements: Samples must be complete and meet the testing standards; documents must be accurate to avoid delays.
Through the above standardized testing, the performance, safety, and compatibility of LED displays can be comprehensively evaluated, providing a basis for product quality certification and market access.
