2VFD Construction Exhaust Tip Getter Filament Lead Contact Lead Anode The VFD has a triode structure in which the front and base plate constitute a vacuum envelope, in which the filament cathode, grid and anode are arranged to form electrodes.Figure above shows:The Aluminium wiring pattern.The Carbon insulation layer printed onto the base plate.The anode pattern printed onto the carbon layer.Grid mesh photo etched from stainless steel & placed over the anodes.Grid & anodes are connected to the pins via the wiring on the base plate.Filament wires (Cathodes) are stretched above the grids & anodes and anchored at each end.The complete structure is then sealed at 500°C & evacuated to torr, to ensure free electron movement.AnodeInsulationLayerGridGlassSubstrateAnodeWiring
3Basic VFD Construction Side GlassFront GlassPhosphor patternFilament wiresGridAnodesIsolation layerWiring pattern etched into aluminium layerEvacuation holeConnection leadsBase Glass+ Sealing cap
4Aluminum Wiring Process Wiring pattern is made by chemical photo etchingA thin Aluminum film is sputtered on 300×300 mm base glass plate
5Isolation Layer Carbon pad Printing Process The isolation layer is printed on the wiring pattern made by etching processThe carbon layer is added for el-ectrical connection improvement on the through hole made by isolation filmTerminal pad printing is added for later external lead frame connection
6Phosphor Printing Process Before printing the phosphor pattern, the sealing paste to be printed for final assembly MaxTemp12:15AMPhosphor pattern is printed (one color for one screen),12 different colours are available
7Self Standing GridA set of grids (metal mesh) are bonded over the top of the phosphor, fixed by SSG bond pasteＦＵＴＡＢＡＶＦＤＣＩＧＶＦＤＦＥＧ
8CIG and Wire BondingIC driver is connected to base glass by aluminium wireUsing IC driver inside VFD, the number of external lead terminals is reduced significantly
9Final Assembly & Exhausting Base plate, Metal frame and Front Glass are assembledThe assembled VFD is sealed in ovenExhausting air creates vacuum tubeGetter flashing removes residual gases
10Aging & Display inspection Aging process to equalize phosphor luminance (e.g C, 2hrs, all segments on)Lead cutting, brushing, soldering & bending processFinal inspection: short circuit, failure modes, double check QA
11Manufacturing Flow Chart (1) Cleaning 300 x 300 glassAluminium sputteringCleaningPhoto-resist printingUV exposureDevelopmentEtchingPhoto-resist removalBase-plate wiring continuity testFirst insulation layer printingCuringDrilling of exhaust holeCleaning & DryingSecond insulation layer printingBase-plate inspectionCarbon printingDryingTerminal pad printingSealing paste printingPhosphor paste printingGrid bonding paste printingGrid bonding assemblyBasic Flow chart – based on BH211GN
13A word about Phosphor“Phosphor” is a generic term. Chemically “Phosphor” is mainly a mixture of zinc and zinc oxides (zno:zn)Phosphors are available in 17 different colours.Most commonly specified is green because it hasgreatest luminance (>2000 cd/sq m)longest lifetime – 30,000 hours to ½ brightnesscost – high volume reduces costcan be filtered to produce range of effectswavelength of 550nmPhosphor description.
14Quality Management Systems Futaba Corporation holds Certificates issued for the following systems:ISO 9001 / ISO Quality ManagementISO Environment ManagementISO TS Extended Automotive QA Requirements
15Our Quality PolicyIt is the quality goal of Futaba Corporation to continuously improve its product acceptance in PPM level, and finally reach the ultimate goal of:Innovation, quality and dependability will continue to be hallmarks of our growth and Futaba‘s commitment to quality in all aspects of operations is the base for our position of market leadershipProcess ControlProcess FMEAControl planInspection criteriaMonitoringTest method.
16Functional / Durability Reliability Testing (1)Test ItemTest ConditionsLifeLighted for 1000 hours at room temperature, rated voltage applied.Vibration fatigueLighted, 4.4G acceleration, 2000 cpm vibration, applied for 4 hours in the X plane and 2 hours each in the Y and Z planes.High temperature operationLighted, for 96 hours at +85° ± 2ºC.Temperature CyclingLighted subject to the specified test conditions as shown, for 5 cycles.30 mins15 mins85°C-0+3-30°C-3+025°C-5+10Functional / DurabilityHeater CyclingFilament voltage at 120% of the rated voltage and cycles without voltage applied to anode and grid.10 seconds5 seconds
17Reliability Testing (2) Test ItemTest ConditionsHigh temperature StorageUnlighted, for 72 hours at +85° ± 2ºC.Low temperature StorageUnlighted, for 72 hours at -40° ± 3ºC.Thermal ShockUnlighted subject to the specified test conditions as shown, for 5 cycles.30 mins5 mins85°C-0+3-55°C-3+025°C-5+10Environmental TestHumidity (Steady State)Unlighted, subject to a relative humidity of 90 to 95%, at a temperature of 40° ± 2ºC, for 96 hours.
18Physical Characteristics Reliability Testing (3)Test ItemTest ConditionsVibration (1)ShockSolderabilityUnlighted, 1.5mm total excursion, 10 – 55Hz frequency. Sweep time cycle 1 minute. Vibration applied for 2 hours in each X, Y and Z planes.Unlighted, 100G maximum acceleration, 6 ms duration, half sine wave 3 times in each X, X’, Y, Y’ and Z, Z’ planes (18 times in total in unlighted state).Immerse in a 230° ± 5ºC solder pot for 5 seconds.Physical CharacteristicsVibration (2)Unlighted, 4G acceleration, 55 – 200 Hz frequency. Sweep time cycle 10 minutes. Vibration applied for 2 hours in each X, Y and Z planes.Resistance to Soldering HeatImmerse in a 280° ± 5ºC solder pot for 30 ± 2 seconds.Terminal StrengthAttach 250g weight to leads. Bend leads through 90° and then return to original position, 3 cycles.