Jinpeng Guide: Is a TFT LCD or OLED Display More Suitable for Industrial Control Equipment?

Industrial control equipment choosing between a TFT LCD screen and an OLED display depends mainly on continuous working time, proportion of static images, ambient temperature, and display effect.

For most industrial control equipment requiring 24-hour operation, long-term display of fixed interfaces, or emphasizing durability, it is recommended to prioritize evaluation of TFT LCD screens.
For equipment pursuing high contrast, slim structure, and dynamic interfaces, OLED displays can be considered.

TFT LCD screens are displays that use thin-film transistors to control liquid crystal pixels and rely on a backlight for illumination; OLED displays are composed of organic light-emitting diode pixels that emit light themselves and do not require a backlight. The 'self-emissive' here means that each pixel can emit light independently, while 'backlight' refers to the unified light source located behind the liquid crystal panel.

Key Differences Between TFT LCD Screens and OLED Displays

TFT LCD screens have relatively stable backlight brightness, and when displaying fixed menus, parameters, and alarm icons, they are usually more likely to control long-term image sticking risk. OLED displays have self-emissive characteristics; black pixels can be turned off directly, so black level performance and contrast are outstanding, but long-term display of the same graphics requires attention to differential aging of pixels.

Image sticking: After the picture switches, the outline of the previous picture remains briefly or continuously visible.
Differential aging: Different pixels produce brightness or color differences due to different cumulative lighting times; in severe cases, it may form what is commonly called 'burn-in'.
Brightness decay: After a display has been used for a period, the emission brightness gradually decreases relative to the initial state.

If industrial control equipment is calculated as operating 24 hours per day, the cumulative working time in one year reaches 8,760 hours; if a fixed interface is displayed 8 hours per day, the annual cumulative display time is 2,920 hours. During selection, expected life, brightness decay, and warranty conditions should be verified together; the figures are for reference only.

Data source: Direct conversion based on 365 days per year, i.e., 24 hours × 365 days = 8,760 hours, and 8 hours × 365 days = 2,920 hours.
Usage note: The actual cumulative time should also be adjusted according to downtime maintenance, standby mode, and workday schedule.

Refresh rate also affects operation perception. Refresh rate is the number of times the screen updates the picture per second, in Hz. Taking the common 60Hz refresh as an example, each frame interval is about 16.7 milliseconds; however, actual touch response is also affected by the controller, interface, and software refresh speed, and cannot be judged by the panel refresh rate alone.

Data source: Calculated as 1,000 ms ÷ 60, each frame interval is about 16.7 ms.
Performance note: Refresh rate is not equivalent to touch response time or whole-device operation latency; the relevant data is for reference only.

In Industrial Environments, Which Indicators Should Be Compared More?

When selecting a TFT LCD screen or OLED display for industrial control equipment, it is not enough to compare only color and thickness; the following points should also be emphasized:

Operating temperature and storage temperature;
Screen brightness, reflectance, and viewing angle;
Vibration and shock resistance capability;
Whole-device dust and water protection rating;
Electromagnetic compatibility;
Long-term supply capability of panels, driver boards, and connectors.

Among them, 'electromagnetic compatibility' refers to the ability of equipment to work normally in an electromagnetic environment while not causing unacceptable electromagnetic interference to other equipment; 'wide temperature range' refers to the minimum to maximum ambient temperature range within which the supplier explicitly guarantees the product can work normally.

According to IEC 60068-2-6:2007 'Environmental testing - Part 2-6: Tests - Test Fc: Vibration (sinusoidal)' issued by the International Electrotechnical Commission, this standard is used to determine the ability of a product to withstand sinusoidal vibration at specified severity levels. Therefore, display modules, connectors, and the whole-device structure should be tested in combination with actual working conditions, rather than judged only by panel parameters.

Authoritative source: International Electrotechnical Commission (IEC), IEC 60068-2-6:2007.
Applicability note: Vibration frequency range, acceleration, sweep cycle, and mounting method should be determined according to the actual use environment of the equipment.

Dust and water protection is a whole-device capability, not a single performance of the display panel. 'IP protection rating' is a grade classified according to the ability of an enclosure to protect against the ingress of solid foreign objects and water. According to IEC 60529 'Degrees of Protection Provided by Enclosures (IP Code)' issued by the International Electrotechnical Commission, the IPX5 water spray test uses a flow rate of approximately 12.5 liters/minute, and the test duration is calculated based on the enclosure surface area and is at least 3 minutes.

Data source: IPX5 test conditions in IEC 60529.
Application note: The final protection rating depends on the front-frame sealing, touch cover glass, seams, interfaces, and housing design; related parameters are for reference only.

In addition, ISO 9241-307:2008 'Ergonomics of human-system interaction - Analysis and compliance test methods for electronic visual displays' issued by the International Organization for Standardization provides analysis and compliance test methods for electronic visual displays. Industrial control equipment should evaluate readability in combination with viewing angle, reflection, luminance uniformity, and ambient light, and should not choose a TFT LCD screen or OLED display based only on laboratory contrast.

Authoritative source: International Organization for Standardization (ISO), ISO 9241-307:2008.
Term explanation: Luminance uniformity refers to the degree of consistency of brightness across different areas of the screen; ambient light readability refers to the ability of the screen to be clearly recognized under strong indoor light or outdoor lighting conditions.

What Does Jinpeng Recommend for Display Selection?

For industrial control equipment with continuous operation, many fixed screens, and long maintenance cycles, Jinpeng recommends prioritizing evaluation of TFT LCD screens and verifying backlight life, wide temperature range, and supply lead time. Backlight life should be based on test reports under supplier-specified temperature, initial brightness, brightness retention rate, and failure conditions; the same value cannot be directly applied across different specifications.

For portable instruments, compact terminals, or dynamic interfaces requiring a deep black background, OLED displays can be evaluated. At the same time, the following measures can be adopted to reduce the risk of differential attenuation caused by long-term lighting of fixed icons:

Regularly rotate or switch interfaces;
Set up a screen saver when there is no operation;
Limit display brightness according to ambient light;
Implement pixel shifting for fixed elements;
Reduce the continuous display time of bright static icons.

'Pixel shifting' means moving fixed graphics periodically by a relatively small distance so that the light-emitting load is distributed across different pixels.

Specifically, three selection thresholds can be established first:

Whether the equipment is operated 8,760 hours per year or only intermittently;
Whether the proportion of static menus, parameters, and alarm icons displayed is relatively high;
Whether the whole device needs to pass IP protection, vibration, and electromagnetic compatibility tests.

Subsequently, prototype verification can be carried out according to IEC 62341-6-2 'Organic light emitting diode displays - Measuring methods of visual quality and ambient performance', as well as relevant ISO and IEC display and environmental standards. For most normally-on industrial control equipment, prioritizing testing of TFT LCD screens is usually more prudent; OLED displays are more suitable for projects where display effect, black level performance, and structural space are given higher weight.