How do you choose the right screen brightness for your industrial equipment?

When designing industrial-grade Human-Machine Interfaces (HMIs) or handheld devices, hardware engineers and product managers often face numerous choices: resolution, size, touchscreen type, etc. However, one parameter is often underestimated, yet it directly determines the success or failure of a device in a real-world environment—screen brightness.

Have you ever encountered this situation: a device that displays perfectly in the lab becomes a “mirror” or a “black hole” once moved to a brightly lit outdoor construction site or a dimly lit mine, making it impossible to read data?

This is the consequence of improper screen brightness selection. Today, we’ll delve into everything about “nits” to help you find that “just right” brightness for your industrial equipment.

What is “nit”? Why is it important?

Brightness is measured in candela per square meter (cd/m²), with the unit being nits (nits).

Simply put, the higher the number, the brighter the screen.

To give you a more intuitive understanding, here are some common screen brightness measurements:

Standard smartphones typically have a brightness between 400 and 600 nits (some high-end models can reach over 1000 nits).

Laptops typically have a brightness between 200 and 300 nits.

Televisions typically have a brightness between 100 and 200 nits (because they are viewed in low-light environments).

In industrial settings, ambient light is much more complex than in homes or offices, therefore the requirements for nits values ​​are much more stringent.

Industrial Scene Brightness Selection Guide

Higher brightness isn’t always better. Blindly pursuing ultra-high brightness not only increases cost and power consumption but also accelerates screen aging and can even generate excessive heat. The key is to “match the application scenario.”

Here are brightness recommendations for different industrial environments:

Indoor/Shaded Environment: 200 ~ 400 nits

Suitable Scenarios: Factory control cabinets, server rooms, medical diagnostic rooms, shopping mall POS machines.

If your equipment is primarily placed indoors and there is no strong direct sunlight, then a standard brightness of 200 to 400 nits is sufficient.

Advantages: Lowest cost, low power consumption, low heat generation.

Note: Even indoors, avoid direct overhead light on the screen surface to prevent glare, which is more detrimental to readability than insufficient brightness.

High-Brightness Indoor/Semi-Outdoor Environment: 500 ~ 800 nits

Suitable Scenarios: Supermarket self-service machines near windows, bright indoor exhibition displays, logistics sorting centers, some vehicle displays.

Compared to standard indoor brightness, standard brightness appears “dull” if there are many lights around the device or if the device might be pushed near a glass door. A screen with 500 to 800 nits ensures vibrant colors even in strong ambient light.

Outdoor Shade/Strong Light Environments: 1000 ~ 1500 nits (High-Brightness Screen)

Applicable Scenarios: Outdoor self-service terminals (kiosks), construction machinery monitoring, agricultural machinery, police body cameras.

This is a watershed moment for industrial displays. When the device is outdoors without direct sunlight, or only occasionally exposed to sunlight, a standard screen becomes completely invisible. You need a so-called “Sunlight Readable” display. This is usually achieved by increasing the number of backlight LEDs or using high-brightness backlight strips.

Direct Sunlight/Extreme Environments: 1500~2000+ nits (Ultra-High Brightness Screen)

Applicable Scenarios: Traffic signal control, heavy construction machinery (excavators, cranes), marine navigation equipment, oil drilling platforms.

This is the most demanding challenge. At midday under the blazing sun, ambient illuminance can reach 100,000 lux. To overcome sunlight, the screen brightness must be at least 1000 nits, with 1500 to 2000 nits typically recommended.

Challenge: This type of screen generates a significant amount of heat, requiring a special heat dissipation structure; otherwise, the polarizer will be damaged.

The Secret Weapon More Important Than Brightness: Optical Lamination

Many customers believe, “As long as the brightness is high enough, everything will be solved.” This is actually a misconception.

When using a screen outdoors, the biggest enemy is often not “insufficient brightness,” but “glare.” There is a gap between the glass and the LCD, causing light to reflect multiple times, turning the screen into a mirror.

This is where optical bonding technology becomes crucial.

By seamlessly bonding the touch panel, LCD panel, and protective glass with optical adhesive (OCA), the air gap is eliminated. This brings two significant benefits:

Significantly reduced glare: Improved contrast, making the screen appear sharper.

Enhanced contrast: Equivalent to visually increasing the screen’s effective brightness.

Frequently Asked Questions(FAQ)

Can a regular commercial monitor with a sunshade be used outdoors to replace a high-brightness industrial screen?

Not entirely feasible. While a sunshade can alleviate some glare, the readability of a commercial screen (300 nits) remains extremely low under direct midday sunlight. Furthermore, industrial environments have stringent requirements for wide temperature range (-20℃~70℃) and dust resistance (IP65), which consumer-grade products cannot meet.

Are OLED screens more suitable for high-brightness industrial applications?

Not recommended at this stage. Although OLEDs offer excellent contrast, their organic materials have poor high-temperature stability under direct sunlight, and continuous high-brightness display of static UIs can easily cause burn-in. High-brightness IPS LCDs remain the mainstream choice for industrial scenarios.

How to test brightness suitability on-site?

The “oblique viewing test method” is recommended: Under the most unfavorable viewing angle (usually 45° side view) and strongest ambient light, the smallest font size (ideally no less than 6pt) and key color icons should still be clearly distinguishable. If you need to squint or get close to see the screen, it indicates insufficient brightness.

Will the touchscreen reduce visible brightness?

Yes. Resistive or multi-layer capacitive screen structures will lose approximately 15–25% of light transmittance. This loss needs to be considered when selecting a screen—if the screen is rated at 1000 nits, the actual brightness after adding a touchscreen will be approximately 750–850 nits.

Does night mode need a separate setting?

Yes. It is recommended to configure Night Mode, controlling the brightness at 50–80 nits and switching to Dark Mode. This is not only for energy saving but also to prevent the driver/operator from being blinded by the bright screen in dark environments (compliant with ISO 15008 automotive display standards).

Summary: How to make the final decision?

When selecting screen brightness for your industrial equipment, you can evaluate it using the following steps:

Determine the environment: Is the equipment primarily used indoors, semi-outdoor, or fully outdoors? Is there direct sunlight?

Set benchmarks:

Purely indoor: 200-400 nits

Semi-outdoor/high-brightness room: 700-1000 nits

Fully outdoors in direct sunlight: >1000 nits

Consider glare: If the ambient light is complex, don’t just focus on the nits value; ask the supplier if they offer optical bonding or anti-glare (AG) glass coating.

Power consumption and heat dissipation: Doubling the brightness will significantly increase power consumption and heat generation. Ensure your motherboard power supply and thermal design are adequate.