| 摘要 |
PURPOSE:To improve color rendering by providing an intermediate valve having transparent infrared beam reflective medium between outer tube of light emission tube thereby rising coldest point temperature and increasing sodium vapor pressure. CONSTITUTION:An intermediate valve 3 having medium for passing visible ray while reflecting infrared ray is provided between a transparent alumina light emission tube 1 and outer tube 2. For example, tubular glasses 4a having transparent infrared ray reflective characteristics are arranged as intermediate valves 3 at the opposite ends of light emission tube 1 while coaxially with light emission tube 1, or in order to further improve reflection effect of infrared ray, transparent infrared ray reflective medium 4b are arranged at the opposite ends of tubular and transparent intermediate valve 3 placed coaxially with light emission tube 1. Consequently infrared ray reflected by transparent infrared ray reflective medium is irradiated to the end section of light emission tube to increase the coldest point temperature while to increase sodium vapor pressure resulting in a high pressure sodium lamp having good color rendering. |
