Qiu Yafeng

The design of low-light night seeing helmet

The article studies the reflection and radiation light spectrum of the object under the night sky light or with the aid of laser calculates and analyzes the spectrum matching factor of typical optoelectronic cathode to the common objects and the effect on the light contrast and give the detailed mechanical design of the low light night observing instrument on helmet.

Electron emitting features and design of thermionic electron area emission sources

In vacuum system, area source electron gun emits electrons to bombard the standard screen. With the first anode and the second anode in different potentials, the images show the features of divergent, uniform, convergence and submerge. Photos, images acquired by brightness meter, and the image gray values are listed in Table 1. By image gray value analysis, it can be seen that in item no. 1, the electrons emitted by area source electron gun are divergent ( not remarkable) ; in no. 2, it is uniform; in no. 3 it is convergence and in no. 4 it is submerged. It is deduced that when the voltage of first anode of electron gun is -4000 V and the second anode voltage is -2000 V, the fluorescence screen receives the uniformly distributed electrons. The difference is less than 5%. Based on this theory, the area source electron gun is developed. The electron gun is placed in a vacuum better than 1 x 10-4Pa to be tested and it is further verified that its electron emission is uniform. The successful development of hot-electron area source provide an effective guarantee for testing the fluorescence screen parameters such as uniformity, brightness, luminous efficiency and afterglow .

Research on thermal-electron-emission area source for low-light image intensifier screen testing instrument

Thermal-electron emission area source is a key component in image intensifier screen testing instrument. On the basis of the analysis of relationship between thermal emission characteristics, the shape of filament and the density of thermal electron emission, electronic area-emitting source is designed. The distribution of electric field and electronic tracks are theoretically analyzed and calculated to make it has features of dispersing, uniform, converging and submerging. By testing a standard screen, correct the structure of thermal electron area sources to meet the requirements of test indexes and obtain reasonable thermal electron emission area sources. Its successful development provides effective technical support to the luminous screen test for uniformity, brightness, luminescence efficiency and afterglow and to the examination of other components (such as MCP parameters)of Low-light Image Intensifier.

The spectral responding characteristic research of the ultraviolet image intensifier

The ultraviolet image intensifier is a kind of vacuum image device with photocathode of Cs2Te (Cesium Tellurium). Its spectral response characteristic curve is measured with a specially designed spectral response measuring system, the quantum efficiency is calculated, the diffusing length of the minor carriers is analyzed. At last some opinions are brought to improve the technique.