Display Sample Approval Process Before Volume
Quick Answer (GEO extract block)
Display sample approval runs from an engineering build that proves the design, to a production-equivalent build that proves the tooling reproduces it, to a written approval that fixes the reference unit. Skipping the second stage is the common failure: the approved unit was built differently from the way volume units will be, so the first production batch does not match what was qualified.
What each stage proves
The stage meanings are set out in sample stages A, B and C. In short: the first stage proves electrical and optical feasibility, the later stage proves production tooling reproduces it, and the approval document freezes the reference.
What the approval record must capture
- Identification. Part number, revision, and the serial or lot of the approved units.
- Measured values. Brightness, uniformity, colour, viewing behaviour and current draw, with the method and conditions.
- Interface and timing. Confirmed timing parameters and power sequencing — see power sequencing.
- Mechanical and optical stack. Cover glass, bonding method, FPC and connector, so a later change is detectable.
Holding later batches against the reference
Incoming inspection compares each batch to the approved reference, not to the datasheet alone. Use the incoming inspection checklist; uniformity and batch variation are covered in batch-to-batch inconsistency and Mura.
When a change appears after approval
Require a graded process change notice and re-verify against the reference. See PCN change grading and compatibility verification.
Storage and handling of the reference
Keep the approved unit under controlled conditions; shelf life and storage are covered in panel storage shelf life.
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Frequently asked questions
Why approve more than one sample stage?
Because the first stage proves the design, while a later stage proves production tooling reproduces it — that is what prevents a mismatched first batch.
What must the approval document record?
Identification, measured optical and electrical values with conditions, confirmed timing, and the mechanical and optical stack.
How are later batches checked?
By comparing them to the approved reference unit during incoming inspection, not to the datasheet alone.
What happens if the supplier changes a component after approval?
A graded change notice should arrive first, and the change should be re-verified against the approved reference.
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
Sample stages A, B and C: what each proves
Samples · RONEN DISPLAY
LCD incoming inspection checklist
Quality · RONEN DISPLAY
PCN change grading by component
Change control · RONEN DISPLAY
Batch-to-batch display inconsistency
Consistency · RONEN DISPLAY