For AV System Manufacturers: Choosing the Right Panel Size for Your Product

Determining the right panel size for an AV LCD system is a crucial part of the design process, that sometimes, even the most experienced engineers and system integrators can struggle with.

In this article, we aim to simplify the panel size selection step for you by providing essential pointers for your AV LCD system design process. These pointers are based on DISCAS standard, a first of its kind standard, developed by leading industry and academic experts.

So, without any further ado, let’s get started.

The Viewing Category

The very first thing you want to establish is the viewing category of your to be designed AV LCD system.

Every AV LCD system can be classified under either one of these two viewing categories:

  • Basic Decision Making (BMD)
  • Analytical Decision Making (ADM)

BDM AV LCD systems serve to help viewers with basic decision making based on the information displayed on the screens. Some examples of the systems falling in this category include displays for classrooms, boardrooms and menu screens installed at restaurants.

ADM AV LCD systems serve to help viewers with critical decision making by displaying minute details of an evolving situation on the screens. Typical examples of ADM AV LCD systems include video walls for surveillance, medical imagery systems, LCD displays installed at plants etc.

After you have established the viewing category for your product, the next step in the process is determining the minimum image height best suited for your application.

The Minimum Image Height

Image height is defined as the measured height of the displayed image. It is measured in inches.

When designing an AV LCD system, you must specify an image height based on the distance of the farthest viewer. After all, if the image is clear to the viewer located farthest away from the screen, it will also be clear for other viewers located nearer to the display.

However, before you can calculate minimum image height, you first need to specify the ideal percent element height (%EH) for your application.

What’s percent element height, you ask?

Percent element height is the height of an image element expressed in relation to the overall image height.

Typically, three standards for %EH are used by AV design experts:

  • 2% EH
  • 3% EH
  • 4% EH

Among these, 3% EH is most the commonly specified standard.

To calculate the minimum image height for your AV LCD system, use the following formula:

For BDM AV LCD systems

Image Height = FV / (%EH X 200)

Where FV is the farthest viewer distance, and “200” is the ideal acuity factor for BDM applications.

For ADM AV LCD systems

Image Height = (FV X IR) / 3,438

Where FV is the farthest viewer distance, IR is the desired image resolution, and “3438” is the acuity factor for ADM applications.

Next, you need to define the viewing angle for your AV LCD system. The viewing angle will in turn dictate the ideal closest viewing position (CV)for your application.

The Viewing Angle and the Closest Viewing Position

As per DISCAS, viewing angle for an AV LCD system must not exceed 60 degrees from the edge of the opposite sides of the system’s screen.

To calculate the closest viewing position (CV) for your AV LCD system, use the following formula:

For BDM AV LCD systems

First, work out the vertical viewing factor (VF) which is the sum of the image height and the image offset.

VF = Image height + Image offset

Then, calculate the CV.

CV = VF x 1.732

Where “1.732” is a constant specified for BDM applications.

How much does the viewing angle measures for your calculated CV? Does it fall under the “60 degrees” limit?

For ADM AV LCD systems

There is no CV calculation required for ADM AV LCD systems, since these systems are already meant to be viewed up close.

An Example in Action

Okay, let’s suppose you’re designing a AV LCD display for installation in a boardroom. Your client wants to use the display for presentations, and has provided you with the following deployment details:

  • Farthest Viewing Distance = 215 inches
  • Desired Aspect Ratio = 16:9
  • Intended display height from the floor = 48 inches
  • Viewing height = 48 inches

So, what type of AV LCD system do you think will best suit this application, BDM or ADM?

If you answered BDM, that’s absolutely correct!

Coming to the panel size selection part:

Image Height

Image Height = FV / (%EH x 200)

Image Height = 215 / (0.03 x 200)

Image Height = 35.83 inches

Closest Viewing Distance

VF = Image height + Image offset

VF = 35.83 + (48 – 48)

VF = 35.83

CV = VF x 1.732

CV = 62 inches

Recommendation

Choose a panel that’s at least 35.83 inches tall and diagonally 73 inches long. Also, don’t forget to brief your client about the seating position of the closest viewer in the room, which should be 62 inches from the screen.

Are you designing an AV LCD system for a client? Get in touch with us to discuss your AV LCD system design needs; REVO will be happy to assist you in your project.

About REVO

REVO is a global supplier of high-performing industrial LCD display solutions. The company works with OEMs, contract manufacturers and independent electronic distributors, providing them high quality displays and display kits for their specialty product design needs. For more details, please call 1-866-738-6797 or visit the company’s official website.

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