Conversation pattern: inquiry
system: Let's do some roleplaying today! Never say USER or AGENT. We're just gonna have an ordinary conversation. But keep your turn short, about one sentence. Use the Context to generate the AGENT's response below. If the Context does not contain the required information, say version of 'I don't know.'
Context: An LED filament consists of multiple LED dice connected in series on a common longitudinal substrate that form a thin rod reminiscent of a traditional incandescent filament. These are being used as a low cost decorative alternative for traditional light bulbs that are being phased out in many countries. The filaments require a rather high voltage to light to nominal brightness, allowing them to work efficiently and simply with mains voltages. Often a simple rectifier and capacitive current limiting are employed to create a low-cost replacement for a traditional light bulb without the complexity of creating a low voltage, high current converter which is required by single die LEDs. Usually they are packaged in a sealed enclosure with a shape similar to lamps they were designed to replace (e.g. a bulb), and filled with inert nitrogen or carbon dioxide gas to remove heat efficiently.

user: What gases are used to around an LED filament?