| 摘要 |
PROBLEM TO BE SOLVED: To maintain a fluorescent device under a large light emitting quantity condition, a high-resolution condition, and a high-S/N condition by providing electrodes on the electron incident surface and fluorescence radiating surface of a phosphor and applying a voltage across the electrodes, and then, controlling the scattering direction of a charged particle ray to the fluorescence radiating surface. SOLUTION: A transparent electrode 17 is provided and a DC power source 16 is connected between the electrode 17 and a reflecting film 15 which is also used as an electrode so as to apply a voltage across the electrode 17 and film 15. The electrode 17 side is set to a high voltage and the diffusion of an electron beam is prevented by pulling the beam to the incident axis side. The suitable material for forming the electrode 17 includes a tin oxide, indium oxide, titanium oxide., etc. Since the track 13 of the low-energy electron beam which largely affects the deterioration of the resolution and S/N of a fluorescent device is maintained so that the track 13 cannot deviate from the incident axis in a phosphor, the out-of-focus of an image which occurs in the phosphor is reduced and the resolution of the fluorescent device is improved. Namely, the resolution and S/N of the device can be improved even when the applied voltage is low, because the resolution and S/N deteriorating effects of the electron beam become larger as the energy of the beam decreases.
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