What performance aspects require attention when using bar-type displays for traffic information display screen?

This article outlines four key performance indicators to prioritize when using bar-type displays for traffic information display screen:

I. Optical Display Performance (Readability is Paramount)

1. Brightness + Automatic Ambient Light Dimming

• Indoor/underground platforms: 500–1000 nits; semi-outdoor areas with glass canopies: 1000–2000 nits; open-air outdoor areas: ≥2000 nits.

• Must feature automatic dimming via ambient light sensors: high brightness during the day and reduced brightness at night to prevent glare and eye strain, while also extending backlight lifespan.

Traffic displays prioritize text legibility over vivid color reproduction; high brightness and high contrast are the top priorities.

2. Wide Viewing Angle: Horizontal ≥178°, with excellent vertical viewing angles. Passengers on platforms or in carriages are dispersed; train schedules and arrival information must remain clearly visible from various angles without dimming or loss of clarity when viewed from the side.

3. Panel Uniformity: Long bar-type screens are prone to uneven brightness across the display and dark corners. Since these screens display text, uneven brightness can render parts of the text illegible; this is a critical acceptance criterion.

4. Contrast Ratio: ≥1000:1, ensuring crisp, sharp white text on a black background (the standard display mode for transportation).

Distinction: Native bar-type panels vs. cut panels. Cut panels are prone to edge light leakage and stress-related issues, posing higher risks in environments subject to vibration; native stretched bar-type screens are preferred for transportation projects.

 

II. Environmental Adaptability (A Major Pain Point in Transportation)

1. Wide Operating Temperature Range

• On-board/Outdoor: -20°C to +60°C. The display must not crash, glitch (display artifacts), or go black during cold starts in northern winters or under intense heat/sun exposure in southern summers. • The storage temperature range must be wider than the operating temperature range.

2. Ingress Protection (IP) Rating

• Indoor train carriages/underground platforms: IP54;

• Semi-outdoor areas, open-air platforms, and bus stops: IP65;

• Fully sealed enclosure with anti-condensation design to prevent damage caused by moisture and condensation.

3. Shock and Vibration Resistance (Critical for onboard and subway carriage applications)

Subways and buses are subject to continuous vibration; the unit's structure, internal wiring, connectors, and backlight modules must be reinforced to withstand vibration and prevent issues such as poor contact, screen flickering, or blackouts over time. Compliance with onboard vibration standards (EN50155) is required.

4. EMC (Electromagnetic Compatibility)

Rail transit and bus systems operate in complex electromagnetic environments; devices require interference resistance to prevent screen artifacts or garbled text and to avoid interfering with other onboard equipment. EMC reports are a standard requirement in tenders for transportation projects.

 

III. System Reliability (7×24 Continuous Operation)

1. Long-term continuous operation capability: High MTBF (Mean Time Between Failures) is essential, as transportation equipment typically runs year-round without shutdown; standard commercial displays are unsuitable for 7×24 operation.

2. Fanless thermal design: Transportation environments are often dusty, making fans prone to dust accumulation and failure; a fanless cooling solution for the entire unit is preferred.

3. Backlight lifespan: Low backlight degradation is required; since transportation displays remain lit for extended periods, rapid backlight decay would cause the screen to become progressively dimmer.

 

IV. System and Interfaces (Integration with Transportation Systems)

1. Communication interfaces: HDMI, RS485, and Ethernet ports; supports integration with PIS (Passenger Information Systems) and transit broadcast control platforms; supports offline caching to ensure preset trip and arrival information remains visible during network outages.

2. Signal stability: Low latency for screen transitions and rapid updates of trip information; stuttering or lag is unacceptable.

3. Supports scheduled power on/off and remote status reporting (feedback on screen faults, temperature, and brightness levels) to facilitate operations and maintenance.