What is viewing angle?

The viewing angle of a display or screen refers to the range of angles from which the screen can be viewed while maintaining a clear, undistorted image. This is an important characteristic of display technologies, as it determines how widely the display can be viewed without significant degradation in image quality.

How viewing angle works

The viewing angle of a display is primarily determined by the underlying display technology. Traditional LCD (liquid crystal display) panels often have relatively narrow viewing angles, where the image quality starts to degrade significantly when viewed from off-center positions. This is because LCD pixels rely on the alignment of liquid crystal molecules to control the light passing through, and this alignment can be disrupted at wider viewing angles.

In contrast, display technologies like IPS (in-plane switching) LCD, OLED (organic light-emitting diode), and newer LCD variants like VA (vertical alignment) and PLS (plane to line switching) typically offer much wider viewing angles. These technologies use different methods to maintain the proper alignment of pixels across a wider range of viewing angles, resulting in a more consistent image quality regardless of where the screen is viewed from.

Measuring and specifying viewing angle

Viewing angle is typically measured and specified as the maximum angle (from the center of the screen) at which the image brightness or contrast ratio drops to a certain percentage of the on-axis (straight-on) value. Common specifications include the horizontal and vertical viewing angles, often expressed as the "total" viewing angle (e.g., 178° horizontal, 178° vertical).

In addition to overall viewing angle, display manufacturers may also specify the "optimal" viewing angle range, which is the area where the image quality is considered to be at its best. Outside of this optimal range, the image quality may start to degrade, but the display will still be viewable to some extent.

Importance of viewing angle

The viewing angle of a display is an important consideration for many applications, especially those where the display needs to be viewed from different positions or angles. Some key use cases where viewing angle is important include:

Presentation and collaboration: Displays used for presentations, meetings, and group collaboration need to be viewable from various positions around the room.
Digital signage and public displays: Screens in public spaces, such as airports, malls, and restaurants, need to be visible from multiple angles to accommodate diverse viewing positions.
Automotive displays: In-vehicle displays, such as infotainment systems and dashboard screens, must maintain image quality when viewed from the driver's and passenger's seats.
Home entertainment: Larger TVs and home theater displays are often viewed from a variety of angles within a room, so a wide viewing angle is desirable.

Best practices and considerations

When selecting a display for a particular application, it's important to consider the required viewing angle range and ensure that the display technology can meet those needs. Some additional best practices and considerations include:

Understand the optimal viewing distance: Displays have an ideal viewing distance range where the image quality is best. Exceeding this range can impact the perceived viewing angle.
Consider ambient lighting conditions: Displays with wider viewing angles may be less affected by changes in ambient lighting, which can impact image quality and contrast.
Prioritize viewing angle over other display specs: In applications where viewing angle is critical, it may be necessary to prioritize this characteristic over other display features like resolution or refresh rate.
Test displays in the intended environment: Whenever possible, evaluate potential display options in the actual environment where they will be used to ensure the viewing angle meets requirements.

Real-world examples

Here are a few examples of how viewing angle impacts the performance of displays in different settings:

In a conference room setting, a display with a wide 178-degree viewing angle allows all participants to clearly see the presentation, regardless of where they are seated around the table.

In a digital signage application at an airport, a display with a wide viewing angle ensures that the information is easily visible to passengers walking by from various directions.

In a home theater setup, a TV with a narrow viewing angle may result in image quality degradation for viewers seated at the edges of the room, whereas a display with a wider angle maintains a consistent, high-quality image across the entire seating area.