By taking extreme care at the design stage and through the development cycle of an itron VFD, Noritake aims to achieve the highest quality levels. The following tests are performed to evaluate and confirm this requirement.

1. Initial Failure
100% aging and screening procedures are done to eliminate all the initial failures.

2. Random (Accidental) Failure
Rare occurrence of this problem means that failure rate should be less than 10 ppm.

3. Wear and Tear Failure
Due to the nature of its construction, the VFD is inclined to a gradual degradation of display quality over a period of time. The longevity during which the quality is retained (so called lifetime) is attributable to the degradation of efficiency of the filament shaped cathode used in VFD'S. Under normal conditions, typical MTTF figures of 80,000 to 100,000 hours are common, while it is possible to extend this to 300,000 hours with some modification in design.
NORITAKE strongly recommends all VFDs shall be used within a specified range of operating electric rating, as the life may fluctuate greatly according to the filament voltage applied.
VFD is also liable to a degradation of display quality if subjected to a prolonged storage period.

4. Reliability Tests

5. Criteria of Quality Assurance
Prior to shipment from NORITAKE, the following inspection is performed.

Table 2 MIL-STD-105D Single Sampling Method

	Inspection Level	AQL	Items
Major	II	0.1	Circuit open, Short circuit Non-luminescence
Minor 1	II	0.65	Electric characteristics Uniformity of Luminescence
Minor 2	II	1.0	Appearance

6. Warranty
Warranty on the itron VFD expires 12 months after delivery (shipment) from NORITAKE.

7. Quality Assurance Organization

8. Process Chart

9. Trouble-Shooting System (Control Plan For Quality Problem)