| 摘要 |
PURPOSE:To facilitate minute luminance control, by providing a metal-oxide- semiconductor field-effect transistor to constitute a switching element for luminance control, and making the thickness of the gate film of the transistor large. CONSTITUTION:A metal-oxide-semiconductor field-effect transistor 4, which is made of a drain 4a, a gate 4b and a source 4c and caused to act as a switching element, is provided on a semiconductor substrate 3. A fluorescent substance 5 is provided on the drain 4a. A display module 7 is composed of the transistor 4 and the fluorescent substance 5. A plurality of such display modules are juxtaposed vertically and horizontally to constitute a fluorescent character display tube. The thickness of the gate film of the transistor 4 is made large enough to put it in operation in a weak inversion area wherein a leakage current increases. As a result, the gradient of a characteristic line of control voltage versus luminance is made moderate to facilitate minute luminance control. Besides, the margin for noise is increased, and a dimensional accuracy is attained to make the tube compact.
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