Have you ever found it difficult to read an ATM screen from the side or noticed how a display appears washed out and distorted when viewed at an angle? This common issue in display technology is related to an aspect of the design known as the viewing angle, which determines how well a screen maintains its image quality when viewed from different positions.

In this article, we will explore what a viewing angle is, how it works, and practical ways to improve display performance for better visibility and usability.

What is a Viewing Angle?

A viewing angle is a display technology specification that defines the optimal angle for maintaining acceptable image quality, including clarity, brightness, contrast, and color accuracy. Outside the specified viewing angle range, the screen’s image quality begins to degrade. For example, colors may appear washed out, contrast levels may drop, or the image may become blurry or distorted.

Learn more: Nits vs. Lumens vs. Luminance

Bias Angle

The bias angle is the specific angle from the center-perpendicular where a display delivers its best image quality. This angle is pre-determined during the display's design and manufacturing phase and is often described using clock positions, such as 12:00 (Top View) or 6:00 (Bottom View), depending on the orientation of the optimal viewing position.

While the viewing angle refers to the range where image quality remains acceptable (e.g., ±20° from the bias angle with a contrast ratio of 4:1), the bias angle determines the point of maximum contrast and clarity. For instance, in a 12:00 display, optimal viewing occurs at 25° above the vertical.

Viewing Angle vs. Viewing Cone

Viewing angle and viewing cone are related but distinct concepts. Viewing angle refers to the specific direction where a display delivers its best image quality, while the viewing cone encompasses the entire 3D range of angles over which the display maintains acceptable image quality.

• Viewing angle: Focuses on a single axis (horizontal or vertical).
• Viewing cone: Describes the combined viewing range across all directions in 3D.

Viewing Angle Measurements

Viewing angles can be described in several ways, and you may encounter different terms depending on the source. Here are the most common methods:

• Clock Positions: Often used in the display industry, especially for LCDs. Terms like 6:00 o’clock (bottom) or 12:00 o’clock (top) indicate the optimal viewing direction.
• Directional Terms: Simplified descriptions like top, bottom, left, or right viewing angle provide an intuitive understanding of the preferred viewing orientation.
• Numerical Degrees: The most precise method, specifying the range of visibility in degrees (e.g.,±60° horizontally and ±60° vertically) from the center of the display.

Learn more: Types of LCDs

Choosing the Correct View Angle for Your Application

Selecting the correct viewing angle is crucial to ensure the best user experience when interacting with a display. Most electronic devices are designed with a preferred viewing position in mind, depending on how and where they are used.

Understanding LCD types such as transmissive, reflective, and transflective and how they interact with light can help you choose the right one for your needs. Learn more here. Comparing OLED and LCD technologies can also guide your decision. Find out more here.

6:00 (Bottom View)

This orientation is ideal for devices where the user typically views the screen from below. Common examples include:

• Handheld devices like smartphones and tablets.
• Desk-mounted calculators and payment processors.
• Industrial control panels and machinery interfaces.
• Portable medical devices.

12:00 (Top View)

This orientation is perfect for displays that are viewed from above. Common examples include:

• Dashboard displays in cars, airplanes, and boats.
• Gas pumps, ATMs, and self-service kiosks.
• Displays in public transportation or retail environments.

Learn more: TN LCDs vs. IPS LCDs

Viewing Angle Example

Let's consider a 6:00 (bottom view) display. When viewed from an angle 25 degrees below the vertical, the display achieves optimal contrast and appears best. However, if the viewer lowers their gaze by an additional 30 degrees, they will notice a decrease in contrast, although the display remains readable. Moving the viewing angle any further below the display will result in a significant reduction in contrast, making it difficult to read.

Display Contrast Adjustment For Performance

Contrast adjustment can indirectly help improve the perceived viewing angle of a display, but it doesn’t fundamentally change the display's inherent viewing angle limitations. Here's how it works:

• Improved visibility at angles: By increasing contrast, the difference between light and dark areas of the screen becomes more pronounced. This can make content easier to see from wider angles, even if the display's native viewing angle is limited.
• Compensating for washout: At extreme angles, many displays (especially LCDs) suffer from color washout and reduced contrast. Adjusting the contrast settings can mitigate this effect to some extent, making the image more readable.
• Backlight control: In some displays, backlight intensity can affect contrast perception. A brighter backlight can improve visibility at wider angles, though this may also increase power consumption.
• Improving visibility with BEF: Improving visibility beyond the optimal viewing angle requires better contrast and brightness. Brightness Enhancement Film (BEF) increases screen brightness without consuming additional power and may improve visibility at wider angles. Learn more about BEF and its benefits here.

Conclusion

Choosing the correct viewing angle is essential for optimal display performance based on its intended use. Narrow angles work best for single-user devices, while wider angles are ideal for shared applications. Aligning the orientation with the user's perspective improves clarity, functionality, and the overall experience. 

At Newhaven Display, we can develop and manufacture a display tailored to your unique specifications, ensuring the perfect solution for your needs.