Benefits of Open Frame Displays vs Embedded LCD Display Kits

An open frame display is a monitor supplied as a bare metal chassis, with the LCD panel, video controller and any touch screen already fitted but no outer bezel, stand or housing, so it can be built into a kiosk, machine or enclosure. It plugs into a computer like any other monitor, through HDMI, DisplayPort, VGA or USB-C, yet it disappears inside the product it serves.

Things Embedded works with machine builders and OEMs throughout the UK on built-in displays and the computers that drive them. Some of these applications need a frameless screen in a confined space, and there are two ways to get one: an open frame display, or an embedded LCD display kit, where you buy the bare panel, a controller board and cables and assemble them yourself. An embedded LCD kit can give the thinnest, lowest-cost build at high volume. An open frame monitor offers the same frameless result with far less integration work, because it connects to your chosen computer through standard plug-and-play video ports.

This guide explains what each option includes, compares them with panel mount and rear mount monitors and open frame panel PCs, then covers the specifications to check, how to mount and seal an open frame display, and how to choose between them.

The table compares the four ways to put a screen inside equipment. Open frame displays and open frame panel PCs are finished products; an embedded LCD kit is a set of components; a panel mount monitor brings its own sealed front bezel.

For most of the projects we see, the choice is between an open frame monitor driven by a separate computer and an open frame panel PC that combines the two. A kit only pays back when the volumes are high enough to absorb the extra engineering.

An open frame display, also called an open frame monitor or open frame LCD, is an LCD built into a bare metal chassis without an enclosure or bezel. The chassis carries the panel, the controller board that turns a video signal into something the panel can show, the power input and, where fitted, the touch screen and its controller. Mounting holes on the rear and sides, usually including a VESA pattern, let you fix it behind an aperture in your own housing.

That flexible design is the main advantage. The display can be installed into existing equipment or structural housings with open apertures, and the end user sees your bezel and your branding rather than a monitor. The chassis offers both rear and VESA mounting, so you can choose the fixing that suits the application.

Inside, the LCD works like any other. Its pixels are arranged in a rectangular grid, and each pixel has red, green and blue sub-pixels that can be turned on or off. With all sub-pixels off the screen appears black; with all of them fully on it appears white; and adjusting each level gives millions of colour combinations. A backlight behind the panel supplies the light, and on current displays that backlight is LED.

Where open frame displays are used

Open frame LCD monitors are used across commercial and industrial sectors: point-of-sale and self-service kiosks, ATMs and vending machines, ticketing, surveillance systems, gaming machines, industrial automation, food processing and manufacturing equipment. Our case study on self-service kiosk computers for OEMs shows how the display and computer are specified together.

An embedded LCD display kit is the same screen taken apart. Instead of a finished monitor, you receive the bare LCD panel and the parts needed to drive it, and you design the mechanical mounting, cabling, thermal path and electrical protection yourself. Kits give the thinnest, lightest build and the most freedom over shape, which is why they appear in high-volume consumer-facing products and slim enclosures.

The panel itself has no HDMI or DisplayPort socket. It takes a low-level digital interface, usually LVDS or eDP, with timings specific to that panel. Either the computer drives it directly from an LVDS or eDP output, which many embedded boards provide, or a controller board converts a standard video input into the panel’s signal.

With a kit, the finished assembly is your product. Electromagnetic compatibility, safety marking and long-term supply of a matched panel and controller usually fall to you, and a change of panel revision can mean new firmware and new EMC testing. That is manageable at volume with an engineering team behind it; it is a lot to take on for a run of 50 machines.

An open frame LCD display offers the same frameless benefits as a kit whilst simplifying integration and pairing with your chosen computer. The decision usually comes down to volume, engineering time and how much of the display you want to own.

Are you designing the display, or designing a product that needs one? If it is the second, an open frame display is usually the right starting point.

Open frame is one of several mounting styles for a built-in screen. The difference is what forms the front face and the seal.

For a cabinet door or machine panel, panel mount monitors are the quickest route to a sealed front. For a flush glass finish set into a sheet-metal panel, rear mount monitors fit from behind. Where the screen sits on an arm or desk, an enclosed chassis monitor is simpler. Our guide to choosing an industrial HMI puts all of these in the context of the operator station.

With plenty of options on the market, these are the specifications that decide whether an open frame display suits your product.

Size, format and resolution

Open frame LCD monitors range from screens as small as 5.7″ to large format versions, with 27″ and 32″ popular for retail and signage and 42.5″ available for large installations. They come in the industry-standard monitor resolutions and in both 4:3 and widescreen formats. High resolutions such as 1920 × 1080 full HD and 4K tend to be most popular in retail and digital signage, where content is king. Stretched displays with bar formats such as 1920 × 720 suit passenger information and machine status strips.

Touch overlays

Open frame monitors can be preconfigured with touch overlays to meet operators’ requirements. The most common are resistive and PCAP, with PCAP now the more popular.

Resistive touch can be activated with any object, such as a finger, stylus or glove. Where operators wear thick gloves without capacitive properties, resistive touch is often the safer choice. Projected capacitive touch (PCAP) has overtaken resistive as the dominant touch technology worldwide. It relies on a conductive object interacting with the charge carried by the screen, and it supports multi-touch with up to 10 touch points, which makes navigating a graphical user interface easy. SAW touch is a third option on some models, giving a clear image for indoor kiosks.

Our range covers PCAP touch monitors, resistive touch monitors and SAW touch monitors, with open frame models in each. Learn more about the different touch types in our guide to choosing the right touch technology for your industrial display.

Open frame LCD monitors are not only suitable for indoor applications but can be integrated outdoors too. High ambient light makes content hard to see unless the backlight is bright enough, so high bright, sunlight readable open frame displays should be chosen for in-window and outdoor installations.

A basic marker for an outdoor open frame display is a backlight of at least 1,000 nits, with wide operating temperature components. Our explainer on what nits are covers how brightness is measured, and you can read more about key features when choosing a sunlight readable display.

Brightness is not the only tool. Optical bonding removes internal reflections from the touch glass, and a transflective display reflects ambient light back through the image, so it stays readable outdoors with a lower-power backlight. Remember that a bright backlight also adds heat inside your enclosure.

Power draw is a figure that should not be overlooked. Most displays now use efficient LED backlights for low power consumption and effective heat dissipation, which makes them durable for long-term use in industrial and retail settings whilst lowering the power bill and carbon footprint.

USB Type-C open frame displays take convenience a step further. With a single USB-C cable carrying video, touch and power from a host with a suitable port, smaller open frame displays, typically up to about 15 inch (15″), need no separate power supply or video cable. Our USB-C monitors use DisplayPort Alt Mode for the video, and our guide to USB versions explains which ports can carry it.

For the lowest energy use, E Ink displays are worth exploring. Electronic paper offers high pixel density and stays readable in sunlight without a backlight, and it draws power only when the image changes. It is best for content that updates occasionally rather than video, and models with rear-mount open frame chassis are available on the market.

Mounting an open frame display means fixing the chassis behind an aperture so the active area lines up with the opening and the front is sealed and protected. The usual methods are:

• Front or flush mount: the chassis is pressed against the inside of the front panel, with a gasket around the aperture, and held by brackets or studs
• Rear VESA mount: a 75 × 75 or 100 × 100 VESA plate fixes the display to an internal frame or bracket
• Side brackets: brackets on the chassis sides fix to rails or a sub-frame inside the enclosure

Whichever method you use, plan the front face as part of the product. The bezel you design hides the panel edge and holds the gasket; the cover glass or touch screen decides how the front resists impact, which our explainer on the IK rating quantifies.

Are open frame monitors waterproof?

Not on their own. An open frame display has no housing, so its protection comes from the enclosure it is built into. With a continuous gasket compressed between a flat front glass and your bezel, a front IP65 rating is achievable, which covers dust and water jets on the operator side. The rear stays inside your enclosure and is protected only as well as the enclosure is. Our IP rating chart explains what each rating covers.

Heat, EMC and cabling

In a sealed enclosure the display shares the heat budget with the computer; our guide to electrical enclosure cooling shows how to calculate it.

Every open frame display needs a computer to drive it. Because the display has standard inputs, almost any industrial computer will do, and the choice follows the rest of the application.

We supply single board computers, embedded box PCs and digital signage players to drive content to the display. Many embedded boards also carry an LVDS or eDP connector for a bare panel, which is the usual route when a kit is chosen. If you are unsure what your computer offers, our guide to monitor connection types covers each output.