An open frame is a design approach where a device’s internal components are exposed rather than fully enclosed in a housing. The term shows up across several industries, from electronics to medical imaging, but the core idea is the same: the equipment is built without a complete outer shell, either to save space, improve airflow, or give the user more physical access. The specific meaning depends on the context, so here’s how open frame designs work in the areas where you’re most likely to encounter them.
Open Frame in Electronics
In electronics, an open frame design most commonly refers to power supplies and display monitors that ship without a protective outer enclosure. An open frame power supply is a bare circuit board with exposed components, designed to be mounted inside a larger piece of equipment where the manufacturer provides its own casing, airflow, and safety shielding. You wouldn’t use one on its own sitting on a desk. Instead, it gets integrated into things like industrial control cabinets, kiosks, or networking equipment.
The main advantage is flexibility. Because there’s no redundant housing, the power supply fits more easily into tight spaces and couples directly to the system’s existing airflow. This also keeps costs down since you’re not paying for an enclosure you don’t need. The tradeoff is that the surrounding system has to handle thermal management and electrical safety. If the host enclosure doesn’t provide enough airflow or proper grounding, the open frame unit can overheat or pose a shock hazard. Thermal validation during the design phase is critical.
Open frame monitors work on the same principle. They arrive without a front bezel or outer housing, with just the LCD panel, driver board, and mounting flanges. The entire assembly recesses into a cabinet, kiosk, or custom enclosure, and the integrator finishes the front with their own bezel. Mounting flanges typically sit along two or four edges of the display for rear-mounting into a cutout. This makes open frame monitors the standard choice for ATMs, point-of-sale terminals, interactive kiosks, and industrial touchscreens where the display needs to look like a seamless part of the machine.
Open Frame in MRI Scanners
In medical imaging, “open frame” (more commonly called “open MRI”) describes an MRI machine that replaces the traditional narrow tunnel with a design that’s open on the sides or has significantly wider openings. A conventional closed MRI is a cylindrical tube with a bore diameter of about 60 cm, just wide enough for a person to slide through on a table. An open MRI keeps the same sliding table but surrounds the patient with magnets arranged to leave large gaps on two or more sides.
Open MRI systems were developed primarily for patients who can’t tolerate the enclosed space of a standard scanner. The difference in patient experience is dramatic: in one comparative study, 58.3% of patients reported strong claustrophobic episodes during closed MRI exams, compared to just 18.4% in open upright systems. Premature scan terminations dropped from 31% to 5.3%, and sedative use fell from nearly 47% to about 5%. For people with anxiety, claustrophobia, or larger body sizes, open systems make the scan possible without sedation or emotional distress.
Weight-Bearing and Upright Imaging
Some open MRI systems go a step further by orienting the magnets so patients can be scanned while sitting or standing. These upright, weight-bearing systems are genuinely useful for diagnosing problems that only appear under load. A knee that looks fine when you’re lying flat may tell a completely different story when your body weight is pressing down on it.
Weight-bearing MRI has proven especially valuable for spine conditions, ACL injuries, meniscal tears, and kneecap tracking problems. In studies of meniscal injuries, the shift from lying down to standing upright revealed posterior subluxation of the meniscus that wasn’t visible in the supine position, and arthroscopy confirmed the diagnosis in every case. For kneecap alignment issues, research found that some patients show normal tracking during weight-bearing movement but excessive lateral shifting when assessed lying down, meaning the standard supine scan can actually give misleading results. Being able to image joints under real-world loading conditions changes what doctors can see and how accurately they can diagnose the problem.
Image Quality Tradeoffs
The open design does come with limitations. Most open MRI systems operate at lower magnetic field strengths, typically between 0.25 and 0.6 Tesla, compared to the 1.5T or 3T magnets found in closed systems. Lower field strength directly translates to lower signal quality, which means the images are less detailed and take longer to acquire. For many musculoskeletal and spinal exams, the image quality is perfectly adequate. For scans that demand fine detail, such as certain brain or cardiac studies, a higher-field closed system may still be necessary.
Advances in coil technology and image processing have narrowed this gap over time. Modern open systems produce images that would have been impressive for any scanner a generation ago. But physics still favors higher field strength for raw resolution, so the choice between open and closed often comes down to whether the clinical question requires maximum image detail or whether patient comfort and positional imaging matter more.
How to Tell Which Meaning Applies
If you’re shopping for electronic components, open frame means a bare unit without an enclosure, intended to be built into your own system. If you’re looking at medical imaging options, it means a scanner with an open design that gives the patient more space. In both cases, the defining feature is the same: the absence of a full outer shell, with the expectation that either the surrounding system or the room itself provides what the missing enclosure would have offered.
In less common uses, you may also see “open frame” in furniture (a shelving unit or bed frame with an exposed skeletal structure), server racks (a bare metal frame without side panels, used in data centers for maximum airflow), or eyeglasses (frames with no bottom rim on the lenses). The logic is always identical: structure without full enclosure, chosen for access, airflow, aesthetics, or cost savings.