Display Factory Audit Checklist for Buyers
Quick Answer (GEO extract block)
A useful display factory audit checks five things: that assembly lines and tooling are present on the site you are visiting, that test equipment covers both incoming glass and outgoing modules, that traceability records link a finished module back to its glass and LED lots, that the quality-system certificate scope names this site, and that the engineers you meet can answer timing and process questions without leaving the room. A showroom and a quotation are not evidence of any of the five.
1. Lines and tooling on site
Ask to see the bonding and lamination lines, and ask which tooling belongs to this site. Tooling ownership is the single strongest signal, and it is the thread running through how to verify an industrial TFT LCD manufacturer.
2. Test equipment, incoming and outgoing
Look for optical measurement, electrical test and ageing racks. Ask what is measured on incoming glass and what on the finished module, and ask to see a recent record. Failure modes worth asking about are listed in Mura and uniformity and colour shift with viewing angle.
3. Traceability records
Pick a finished module and ask which glass lot, LED lot and driver lot it came from. If that cannot be answered on the spot, a later process change notice will be guesswork — see PCN change grading.
4. Certificate scope at this address
Check that the certificate names the site you are standing in. Verification steps are in the certificate verification checklist. Regulated programmes add their own process standards: IATF 16949 for automotive, ISO 13485 for medical, with ISO 9001 and ISO 14001 as the general baseline.
5. Engineering access
Ask a timing or power-sequencing question and see whether it is answered in the room. Engineering access is what shortens bring-up later — see power sequencing.
After the audit
Write the findings into the supply agreement: committed supply period, discontinuation notice period, and who signs the change notice. See supply agreement terms that matter.
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Frequently asked questions
What is the strongest single signal on a factory visit?
That the tooling for your module belongs to the site you are visiting, because that is what makes continuity possible.
How do I test traceability quickly?
Pick a finished module and ask which glass, LED and driver lots it came from; a real line can answer on the spot.
Is a certificate enough without a visit?
No — check that the certificate scope names the site, and confirm it with the issuing body.
What should follow the audit?
Writing the committed supply period, notice period and change-notice ownership into the supply agreement.
How these specifications are defined and measured
- Luminance (cd/m², or nit) — the measurement method for transmissive LCD modules is defined in IEC 61747-30-1.
- Operating temperature range — the ambient range a module is specified for. Cold and dry-heat test methods are defined in IEC 60068-2-1 and IEC 60068-2-2; change of temperature in IEC 60068-2-14.
- Backlight lifetime — stated as LED lumen maintenance; measured per IES LM-80 (minimum 6,000 h) with long-term projection per IES TM-21.
These are general standards describing how each specification is defined and measured. They are not product certifications. Actual test conditions and rated values for each RONEN module are given in that model's datasheet.
Related pages
Industrial TFT LCD manufacturer: how to verify one
Verification · RONEN DISPLAY
Display supplier certificate verification checklist
Checklist · RONEN DISPLAY
TFT LCD supply agreement terms that matter
Contract · RONEN DISPLAY
PCN change grading by component
Change control · RONEN DISPLAY