VFD Production Process & QA

VFD 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 10-7 torr, to ensure free electron movement. Anode Insulation Layer Grid Glass Substrate Anode Wiring

Basic VFD Construction Side Glass Front Glass Phosphor pattern Filament wires Grid Anodes Isolation layer Wiring pattern etched into aluminium layer Evacuation hole Connection leads Base Glass + Sealing cap

Aluminum Wiring Process Wiring pattern is made by chemical photo etching A thin Aluminum film is sputtered on 300×300 mm base glass plate

Isolation Layer Carbon pad Printing Process The isolation layer is printed on the wiring pattern made by etching process The carbon layer is added for el-ectrical connection improvement on the through hole made by isolation film Terminal pad printing is added for later external lead frame connection

Phosphor Printing Process Before printing the phosphor pattern, the sealing paste to be printed for final assembly　　　　 Max Temp 12:15 AM Phosphor pattern is printed (one color for one screen),12 different colours are available

Self Standing Grid A set of grids (metal mesh) are bonded over the top of the phosphor, fixed by SSG bond paste ＦＵＴＡＢＡ ＶＦＤ ＣＩＧＶＦＤ ＦＥＧ

CIG and Wire Bonding IC driver is connected to base glass by aluminium wire Using IC driver inside VFD, the number of external lead terminals is reduced significantly

Final Assembly & Exhausting Base plate, Metal frame and Front Glass are assembled The assembled VFD is sealed in oven Exhausting air creates vacuum tube Getter flashing removes residual gases

Aging & Display inspection Aging process to equalize phosphor luminance (e.g. 60-80C, 2hrs, all segments on) Lead cutting, brushing, soldering & bending process Final inspection: short circuit, failure modes, double check QA

Manufacturing Flow Chart (1) Cleaning 300 x 300 glass Aluminium sputtering Cleaning Photo-resist printing UV exposure Development Etching Photo-resist removal Base-plate wiring continuity test First insulation layer printing Curing Drilling of exhaust hole Cleaning & Drying Second insulation layer printing Base-plate inspection Carbon printing Drying Terminal pad printing Sealing paste printing Phosphor paste printing Grid bonding paste printing Grid bonding assembly Basic Flow chart – based on BH211GN

Manufacturing Flow Chart (2) Substrate insulation inspection Substrate cutting Frame, mesh Hydrogen treatment Terminal forming Filament anchor welding Filament welding Getter welding Mount check Final assembly Sealing Exhausting Getter flashing Baking Aging Lead cutting Lead brushing Soldering In-process inspection Lead forming Labelling External inspection Out going inspection Shipping Packaging

A 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 has greatest luminance (>2000 cd/sq m) longest lifetime – 30,000 hours to ½ brightness cost – high volume reduces cost can be filtered to produce range of effects wavelength of 550nm Phosphor description.

Quality Management Systems Futaba Corporation holds Certificates issued for the following systems: ISO 9001 / ISO 9002 Quality Management ISO 14001 Environment Management ISO TS 16949 Extended Automotive QA Requirements

Our Quality Policy It 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 leadership Process Control Process FMEA Control plan Inspection criteria Monitoring Test method.

Functional / Durability Reliability Testing (1) Test Item Test Conditions Life Lighted for 1000 hours at room temperature, rated voltage applied. Vibration fatigue Lighted, 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 operation Lighted, for 96 hours at +85° ± 2ºC. Temperature Cycling Lighted subject to the specified test conditions as shown, for 5 cycles. 30 mins 15 mins 85°C -0 +3 -30°C -3 +0 25°C -5 +10 Functional / Durability Heater Cycling Filament voltage at 120% of the rated voltage and 20000 cycles without voltage applied to anode and grid. 10 seconds 5 seconds

Reliability Testing (2) Test Item Test Conditions High temperature Storage Unlighted, for 72 hours at +85° ± 2ºC. Low temperature Storage Unlighted, for 72 hours at -40° ± 3ºC. Thermal Shock Unlighted subject to the specified test conditions as shown, for 5 cycles. 30 mins 5 mins 85°C -0 +3 -55°C -3 +0 25°C -5 +10 Environmental Test Humidity (Steady State) Unlighted, subject to a relative humidity of 90 to 95%, at a temperature of 40° ± 2ºC, for 96 hours.

Physical Characteristics Reliability Testing (3) Test Item Test Conditions Vibration (1) Shock Solderability Unlighted, 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 Characteristics Vibration (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 Heat Immerse in a 280° ± 5ºC solder pot for 30 ± 2 seconds. Terminal Strength Attach 250g weight to leads. Bend leads through 90° and then return to original position, 3 cycles.

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