From: A multi-functional design approach and proposed figure of merits for solid state lighting systems

FOM | Formula | Unit | Description |
---|---|---|---|

FOM_{R}
| ΔT/q | K/W | Thermal resistance |

FOM_{R,m}
| ΔT m/q | K kg/W | Thermal resistance based on mass |

FOM_{R,A}
| ΔT A/q |
K cm^{2}/W
| Thermal resistance based on surface area |

FOM_{R,m,A}
| ΔT m A/q |
K kg cm^{2}/W
| Thermal resistance based on mass and surface area |

FOM_{LPW}
| Φ/P | lm/W | Luminous efficacy |

FOM_{LPW,m}
| Φ/P m | lm/W kg | Luminous efficacy based on mass |

FOM_{LPW,A}
| Φ/P A |
lm/W cm^{2}
| Luminous efficacy based on surface area |

FOM_{LPW,m,A}
| Φ/P m A |
lm/W kg cm^{2}
| Luminous efficacy based on mass and surface area |

FOM_{T,L}
| ΔT/Φ | K/lm | Opto-thermal resistance |

FOM_{T,m,L}
| ΔT m/Φ | K kg/lm | Opto-thermal resistance based on mass |

FOM_{T,A,L}
| ΔT A/Φ |
K cm^{2}/lm
| Opto-thermal resistance based on surface area |

FOM_{T,m,A,L}
| ΔT m A/Φ |
K kg cm^{2}/lm
| Opto-thermal resistance based on mass and surface area |