UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Switching characteristics of electrodeless gas-filled bulbs immersed in both A.C. and unipolar, uniform electric fields Richardson, Michael J.


A more complete understanding of the switching characteristics of external electrode gas filled discharge bulbs is needed for many electrical devices (e.g. AC plasma display panels). When a glass (or pyrex) bulb filled with gas (e.g. neon) is placed in an electric field, it can emit light in the form of a pulse. Whether or not a discharge (light pulse) occurs depends on the magnitude of the electric field in the bulb and the various bulb parameters (geometry, pressure, gas, etc.). The field inside the bulb is made up of the field created by the external electrodes, and the field created by any wall charges deposited inside the discharge vessel. The bulbs used in this thesis were of two varieties; spherical bulbs (1 Torr of Ne), and spherical Ne-Xe (5 Torr) bulbs with getters attached to one end spoiling their overall symmetry. The spherical, ungettered bulbs have an isotropic response to the applied field, but possess long time lags (up to 2 seconds) before breakdown occurs. The duration of the time lag can be reduced by increasing the frequency of the applied field. These bulbs also experience an aging process which causes the AC threshold field (the minimum AC field required for breakdown) to increase over time so long as the bulbs are not exposed to any discharges. The gettered bulbs do not possess this aging effect but are unique in that breakdown in an AC field only occurs when electrons and ions are accelerated in a specific direction. Furthermore, the gettered bulbs only exhibit long time lags if they are initially exposed to a low field (too low to induce breakdown) for at least a few seconds. Without the occurrence of time lags, the effects of wall charges (created from previous discharges) can be studied. This thesis presents the theoretical and experimental results which explain these characteristics for both bulb types. The geometry of the gettered bulbs and the relative orientation of the applied field is described along with the necessary apparatus for producing the various electric fields. Finally, the characteristics of the two types of bulbs are compared. Suggestions for improving their switching performance are also advanced.

Item Citations and Data


For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.