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GE SSL-1 Silicon Carbide Yellow LED |
When the SSL-1 was launched it was the world's brightest LED, due to its silicon carbide chip producing a more visible yellow light whose efficacy rises at higher temperatures - although still barely visible in a normally lit room. Despite this limitation it found applications requiring long life, high robustness, low current draw, or the possibility to modulate the light at up to 1MHz - all impossible with filament lamps.
The 1mm² boron-doped SiC chip is soldered onto a TO-18 gold plated kovar transistor header, current being delivered via a gold wirebond at its top surface. A glass lens above the chip focusses its feint glow into a narrower beam of higher intensity. One characteristic of the SiC chip is that most light is emitted from its sides rather than the top, this being exploited in the later SSL-6 with glass package to improve the viewing angle. These SiC LEDs were produced only briefly, and were discontinued before 1970 following the introduction of brighter GaAsP red emitting LEDs such as the Monsanto MV-1 of 1968, and GE's GaP SSL-22 of 1970.
| Manufacturer: | General Electric USA | |
| Lamp Power: | 0.18 Watts | |
| Lamp Voltage: | 3.50 Volts | |
| Lamp Current: | 0.050 Amps | 0.075A maximum |
| Cap Type: | G2.54 Au plated wires | 0.0175" dia. x 1" length |
| Bulb Type: | TO-18 transistor header | |
| Bulb Finish: | Glass lens | |
| Luminous Flux: | ||
| Luminous Efficacy: | ||
| Surface Luminance: | 137 cd/m² | 40 foot-lamberts |
| Beam Distribution: | 40° | to half-peak |
| Colour Temperature & CRI: | CCT: 2510K | CRI: Ra 55 |
| Chromaticity Co-ordinates: | CCx: 0.514 | CCy: 0.477 |
| Peak Wavelength: | 590nm | 80nm half-width to 70.7% of peak |
| Dominant Wavelength: | 581nm | 98% spectral purity |
| Lifetime: | Indenfinitely long | |
| Warm-up & Re-strike Time: | <100 microseconds | to ⅔ peak brightness |
| Burning Position: | Universal | |
| Overall Length: | 6.0 mm | 0.235" (without leads) |
| Factory: | Nela Park | Cleveland, USA |
| Date of Manufacture: | 1967-1969 | |
| Original Value: | US $9.50 (1967) | |
