A flash discharge tube includes tungsten pins configuring a pair of discharge electrodes, and an envelope. The envelope includes a central region, serving as an alkali-free region, which is configured with an alkali-free glass except for quartz glass. The central region becomes in a high temperature state during a firing operation of the flash discharge tube. The central region is smaller than a maximum region enclosing a gas-tight space formed by hermetically sealing the pair of the discharge electrodes and is not smaller than a minimum region enclosing an arc-discharge space formed between the tungsten pins of the pair of the discharge electrodes. The alkali-free region contains either no alkali metal component or not larger than a predetermined amount of an alkali metal component. Then, a trigger electrode is disposed in the alkali-free region. This provides the flash discharge tube featuring a stable short-interval continuous-firing operation.

A flash discharge tube includes tungsten pins configuring a pair of discharge electrodes, and an envelope. The envelope includes a central region, serving as an alkali-free region, which is configured with an alkali-free glass except for quartz glass. The central region becomes in a high temperature state during a firing operation of the flash discharge tube. The central region is smaller than a maximum region enclosing a gas-tight space formed by hermetically sealing the pair of the discharge electrodes and is not smaller than a minimum region enclosing an arc-discharge space formed between the tungsten pins of the pair of the discharge electrodes. The alkali-free region contains either no alkali metal component or not larger than a predetermined amount of an alkali metal component. Then, a trigger electrode is disposed in the alkali-free region. This provides the flash discharge tube featuring a stable short-interval continuous-firing operation.

A structure is provided that includes a partition plate that separates a first space from a second space, in which the first space is filled with a gas that emits light of a first color when irradiated with laser light, the second space is filled with a gas that emits light of a second color when irradiated with the laser light, and the partition plate contains a phosphor that emits light of a third color when irradiated with the laser light. The structure may be cylindrical and the partition plate may be spiral-shaped. Alternatively, the structure may be prismatic and the partition plate may be flat plate-shaped.

A structure is provided that includes a partition plate that separates a first space from a second space, in which the first space is filled with a gas that emits light of a first color when irradiated with laser light, the second space is filled with a gas that emits light of a second color when irradiated with the laser light, and the partition plate contains a phosphor that emits light of a third color when irradiated with the laser light. The structure may be cylindrical and the partition plate may be spiral-shaped. Alternatively, the structure may be prismatic and the partition plate may be flat plate-shaped.