A basic structure of a field emission display apparatus is described in, for example, the special feature “Basic knowledge of an electronic display for young engineers” in the April 2004 issue of a technical magazine “Electronic Material”, pages 94 to 102 (non-patent document 1). The field emission display apparatus is so structured that a cathode substrate on which many electron sources for emitting electrons are formed and an anode substrate to which phosphors are applied are placed opposite each other via a gap. Electrons emitted from the electron source corresponding to each pixel impinge on the phosphor to emit light, so that the field emission display apparatus displays images.
In the field emission display apparatus, the gap needs to be secured and vacuously sealed. In many cases, a plurality of thin spacers are set up between the anode substrate and cathode substrate to prevent the gap from collapsing due to the atmospheric pressure. However, the production, placement, and structure of the spacers which are thin enough not to be seen from the outside are difficult. Moreover, charge-up of the spacers causes turbulence of images. Therefore, a display panel structure requiring less or no spacers is desirable. It can be considered that an anode substrate and cathode substrate are made thick to decrease the flexing due to the atmospheric pressure. However, in a large screen panel, a display panel itself becomes very heavy. Patent documents relating to this are as follows.
Japanese Patent Laid-Open No. H3(1991)-236143 (patent document 1) discloses a conventional display apparatus. A vacuum vessel of this display apparatus includes a front plate formed of a transparent glass plate and a back plate formed of metal and having a box shape. Additionally, another back cover formed of metal and having a box shape is provided covering this back plate to make vacuous a space between the back plate and back cover, so that the lightening is achieved.
Japanese Patent Laid-Open No. H7(1995)-296746 (patent document 2) discloses a conventional image display apparatus. This image display apparatus includes a first envelope in which an image display member is disposed and a second envelope which covers the whole of the first envelope. The insides of both envelopes are made vacuous, so that the deformation of the first envelope due to the atmospheric pressure is prevented.
Further, Japanese Patent Laid-Open No. 2000-100355 (patent document 3) discloses a conventional display apparatus. In this display apparatus, a silicon substrate on which electron sources are formed is placed on a plane glass substrate on the electron source side, a glass substrate on the phosphor side is placed opposite the glass substrate on the electron source side, and a metal network is embedded in or attached to the glass substrate on the phosphor side. Accordingly, a strength of the glass substrate on the phosphor side is improved to achieve the thinning and lightening of the glass substrate on the phosphor side.
[Patent document 1] Japanese Patent Laid-Open No. H3(1991)-236143
[Patent document 2] Japanese Patent Laid-Open No. H7(1995)-296746
[Patent document 3] Japanese Patent Laid-Open No. 2000-100355
[Non-patent document 1] Special feature “Basic knowledge of an electronic display for young engineers” in the April 2004 issue of a technical magazine “Electronic Material”, pages 94 to 102