Safety standards for electronic equipment changed shape a decade ago, and the change affects how a display is treated inside a product. Instead of prescribing distances and component types, the current approach asks you to identify energy sources, decide who can come into contact with them, and then apply safeguards appropriate to the risk.

This article explains what that means for a product built around a display, and what to collect from the display supplier so the assessment does not stall.

What IEC 62368-1 covers and what it replaced

The standard covers audio, video, information and communication technology equipment – the categories that most display-based products fall into. It replaced the two earlier standards that separated information technology from audio and video equipment, which is why older projects sometimes still refer to them.

The practical consequence of the replacement is that a product combining computing, display and media functions is assessed as one device rather than being split between two frameworks. For display-based equipment, that simplifies the scope but requires the whole assembly to be considered together, including the display module and the power supply that feeds it.

Hazard-based thinking rather than prescriptive rules

Documentation is part of the deliverable. The assessment needs to record which energy sources were identified, which safeguards apply to each, and how those safeguards were verified – by construction, by measurement or by test. A file that contains only test reports answers the last question and leaves the first two open.

Documentation is part of the deliverable. The assessment needs to record which energy sources were identified, which safeguards apply to each, and how those safeguards were verified – by construction, by measurement or by test. A file that contains only test reports answers the last question and leaves the first two open.

Documentation is part of the deliverable. The assessment needs to record which energy sources were identified, which safeguards apply to each, and how those safeguards were verified – by construction, by measurement or by test. A file that contains only test reports answers the last question and leaves the first two open.

Documentation is part of the deliverable. The assessment needs to record which energy sources were identified, which safeguards apply to each, and how those safeguards were verified – by construction, by measurement or by test. A file that contains only test reports answers the last question and leaves the first two open.

The framework classifies energy as a hazard, then describes safeguards for classes of energy: electrical, thermal, fire and mechanical. Three concepts do the work. An energy source is a point where energy reaches a level that could injure or ignite. A safeguard is a construction feature that prevents or limits exposure. A safeguard has to be verified, either by construction, by test or by a combination.

For a display product, the consequences are practical rather than abstract. You need to know what energy levels exist in the assembly, where a person could come into contact with them – including through a touch surface – and how the construction prevents harm. That reasoning has to be documented, which is why a test report alone rarely satisfies an assessment.

Where the display sits in the energy-source assessment

Most display modules are low-energy devices from the safety perspective: their inputs are below the levels that constitute an injury hazard, and their backlight drive is contained within the module. The interesting points in the assessment are usually the boundaries.

The first boundary is the power supply feeding the display: if it is an external adapter or a mains-powered supply inside the enclosure, it carries the higher energy classes and dominates the assessment. The second is any interface that leaves the enclosure, such as a bus, a camera link or an external touch connection, because those contacts may be accessible to the user. The third is the panel itself, where the backlight driver can produce voltages well above the system rail – bounded inside the module, but relevant to the module’s own construction and documentation.

Insulation, spacing and user-contact surfaces

For a display product the touch surface is the most interesting mechanical element, because it is designed to be touched. The assessment has to show that the user cannot contact a hazardous energy level through it, including at edges, around the frame and at any point where the cover glass is bonded or gasketed to the housing.

Insulation and spacing decisions then follow from that: the isolation between the touch sensor and any higher-voltage circuit, the separation between the display assembly and mains-carrying parts, and the creepage and clearance distances that the standard requires for the relevant energy class and environment.

The detail that catches people out is the touch controller, which is electrically connected to both the sensor the user touches and the system’s ground. Its isolation and its placement in the assembly belong in the safety assessment rather than only in the EMC one.

Backlight, driver and power considerations

Inside the module, the backlight driver produces the highest voltages in the display assembly. Modern panels manage this internally, but a design that uses an external driver brings that circuit into the product’s own assessment.

Two questions decide how much work is involved: is the driver circuit accessible to the user or only to a service technician, and is the module’s own construction documented well enough to rely on? Where the module carries its own driver and its documentation covers the internal isolation, the assessment can usually treat the module as a component with defined properties.

Material and flammability interfaces

Enclosure materials, internal plastics and the display’s own materials have flammability expectations that depend on where they sit and what energy is nearby. A display module usually arrives with a flammability rating for its components, which is why the module’s material documentation belongs in the file.

The interface that matters is between the module and the rest of the product: adhesives, gaskets, tapes and any added plastics are the purchaser’s materials, and their ratings are the purchaser’s responsibility.

What to request from a display supplier

Which certifications and quality documents a display maker holds is covered separately in LCD factory certifications. Ask for the documents that support the assessment rather than a marketing statement about compliance.

Request	What it supports
Module specification with input voltage and current	The energy-class assessment at the interface
Description of internal isolation and construction	The boundary between the module and the product
Material and flammability ratings for components	The fire hazard assessment
Temperature limits and thermal behaviour	The thermal hazard assessment
Any existing component-level test evidence	Avoiding duplicate testing
Documentation of the backlight drive arrangement	Deciding whether the driver is in scope

Test implications for a display-based product

Sample selection is worth planning in advance. The laboratory needs the configuration that will be sold: the production enclosure, the production cable and the final power supply. Where a variant will exist – a different size, a different touch option – decide early whether it is covered by the same assessment or needs its own, because that decision affects how many samples are built.

Sample selection is worth planning in advance. The laboratory needs the configuration that will be sold: the production enclosure, the production cable and the final power supply. Where a variant will exist – a different size, a different touch option – decide early whether it is covered by the same assessment or needs its own, because that decision affects how many samples are built.

Sample selection is worth planning in advance. The laboratory needs the configuration that will be sold: the production enclosure, the production cable and the final power supply. Where a variant will exist – a different size, a different touch option – decide early whether it is covered by the same assessment or needs its own, because that decision affects how many samples are built.

Sample selection is worth planning in advance. The laboratory needs the configuration that will be sold: the production enclosure, the production cable and the final power supply. Where a variant will exist – a different size, a different touch option – decide early whether it is covered by the same assessment or needs its own, because that decision affects how many samples are built.

Testing follows the assessment. In practice, the laboratory will want to see the construction, the arrangement of the sample as it will be sold, and the reasoning behind the safeguards. Temperature measurements at accessible surfaces and on components are common, as are touch-current and dielectric tests at the interfaces.

For a display product the sample’s configuration matters: whether the display is powered from the final supply, whether the cables are the production type, and whether the enclosure is the production version. A test performed on an engineering sample with a bench supply frequently has to be repeated once the real configuration is available.

Common surprises at the test house

Four issues recur. The touch surface turns out to be a contact path that was not considered. The external adapter supplied is a different model from the one assessed. Temperature limits are exceeded at a component that was assumed to be cool, usually in a sealed enclosure. Or the module’s documentation turns out to describe a different variant from the one fitted.

All four are cheaper to prevent than to fix, and all four are prevented by treating the display as part of the product’s safety assessment rather than as a bought-in item that arrives compliant.

Compliance preparation checklist

Item	Status to reach before the laboratory
Power architecture	Final supply identified, with its energy class
Accessible surfaces	Touch surface and any external connector assessed as contact paths
Isolation and spacing	Dimensions verified against the relevant class
Materials	Flammability ratings recorded for added materials
Supplier documents	Module specification, construction description and material ratings collected
Sample	Production-representative construction and cables
Reasoning	Hazard, safeguard and verification documented for each energy source

If a display-based product is approaching its safety assessment, the fastest preparation is to map every energy source and every accessible surface before the sample is built. If you need the display documents that support that work, contact us with the part numbers and the destination market. For the EMC side of the same product, see the article on grounding and shielding design.

Frequently asked questions

Does the display module need its own safety certificate?

Not necessarily. What matters is that the module’s properties are documented well enough for the product’s assessment to rely on them. A component certificate helps but is not a substitute for assessing the product.

Is the touch surface treated as an accessible part?

Yes, because it is designed to be touched. The assessment has to show that no hazardous energy is reachable through it, including at edges and fixings.

Can we reuse an assessment from an earlier product?

Only to the extent that the construction, supply and display are the same. A different module, a different adapter or a different enclosure invalidates the parts of the assessment that depend on them.