How do thermal IR cameras even work without liquid nitrogen?

Years ago thermal infrared cameras used to require cryogenic cooling to prevent infrared emitted by the camera itself from spoiling the image. But today's thermal cameras don't require that. How is that even possible? Topdon Amazon prime day sale, July 2025: Monocular: TS004 US: $424.99 USD sale price https://www.amazon.com/dp/B0D56CNCW1?... Canada: $551.2 CAD sale price https://www.amazon.ca/dp/B0D56CNCW1?m... Pistol style: TC004 US: $274.55 USD sale price https://www.amazon.com/dp/B0BRK4SGD2?... Canada: $369 CAD sale price https://www.amazon.ca/dp/B0BRK4SGD2?m... TC004MINI US: $141.55 USD sale price https://www.amazon.com/dp/B0F29969G1?... Canada: $207.19 CAD sale price https://www.amazon.ca/dp/B0DJD2P3FF?m... Smart phone plugin style: TC001 US: $198.99 USD sale price https://www.amazon.com/dp/B0B7LMB22Q?... Canada: $279.99 CAD sale price https://www.amazon.ca/dp/B0B7LMB22Q?m... TC002 US: $229 USD sale price https://www.amazon.com/dp/B0BYHP8KM9?... Canada: $319.2 CAD sale price https://www.amazon.ca/dp/B0BYHP8KM9?m... TC002C US: $229 USD sale price https://www.amazon.com/dp/B0D3DZV19P?... Canada: $319.2 CAD sale price https://www.amazon.ca/dp/B0D3DZV19P?m...