The scanning technology of LED displays is one of the core technologies of their driving system. Essentially, it uses the "time-division multiplexing" principle to illuminate pixel units row by row/column by column using a driver chip to achieve image display. Its core indicator is the scan count (scan ratio), which is the number of pixel rows that can be controlled by the same driving channel (e.g., 1/8 scan means 8 rows of pixels share one set of driving circuits). The classification of low, medium, and high scan is based on the scan count, and the three differ significantly in driving efficiency, brightness, power consumption, and cost. Their specific characteristics are as follows:
Low scan technology
Low scan typically refers to a scan count of ≤1/8 (commonly 1/4, 1/6, 1/8 scans), and was the mainstream driving solution for early LED screens and outdoor large screens.
Core features
Low driving cost is a key advantage. Because fewer driving chips are needed per unit area, the hardware investment and circuit design are less complex. This makes it the most affordable option of the three.
Brightness performance is also excellent. The high single-pixel illumination time ratio and efficient current driving allow for a high brightness output, which is essential for visibility in bright outdoor settings.
However, there's a trade-off. Power consumption and heat generation are higher. The relatively low number of load lines per channel, combined with the high driving current density, leads to increased power use and significant heat production during extended operation.
Finally, the refresh rate is somewhat limited. The driving timing constrains the screen refresh rate, which is typically lower than that of medium and high scanning solutions. This can result in screen flickering, especially in low frame rate situations.
Mid-scan technology
Medium scan generally refers to a scan count of 1/8 to 1/16 (commonly 1/10, 1/12, and 1/16 scans), which is a balanced solution that takes into account both performance and cost.
Core features
Balanced Performance: Slightly higher than low-scan in terms of driving cost, but far lower than high-scan; brightness covers semi-outdoor and indoor strong light scenarios, while power consumption and heat management are superior to low-scan.
Moderate Refresh Rate: The screen refresh rate can reach over 1920Hz, meeting the smoothness requirements of regular video playback and image/text display without noticeable flickering.
High Adaptability: The driving circuit has high compatibility, allowing flexible adjustment of brightness and power consumption parameters according to the scenario, combining practicality and cost-effectiveness.
High-scan technology
High scan rate refers to a scan count ≥ 1/16 (commonly 1/32, 1/48, and 1/64 scans, with small-pitch screens reaching 1/128 scan), which is the core driving solution for indoor high-definition small-pitch LED screens.
Core features
High display precision is achieved through the utilisation of numerous driver chips, which facilitate more precise control over pixel illumination timing. This architecture supports elevated refresh rates, typically exceeding 3840Hz, and a broad range of greyscale levels. Consequently, the resulting image is devoid of graininess and flicker, thereby satisfying the requirements of high-definition viewing at close distances.
Furthermore, the design promotes low power consumption and minimal heat generation. The high number of rows loaded per channel contributes to a reduced drive current density. This, in turn, results in significantly lower overall power consumption and heat production when contrasted with low- and medium-scanning solutions, thereby enhancing operational stability.
The high cost of drivers is a major factor. Each unit needs many driver chips, requiring a powerful control card and cooling system. As a result, the hardware and technical expenses are the highest of the three options.
The brightness is good for indoor use. Because each pixel is lit for a short time, the overall brightness is limited. This makes it suitable for low-light or standard indoor settings, but not for bright outdoor environments.
