| 摘要 |
PURPOSE:To improve a projected picture quality by packing an optical medium whose refractive index is higher than that of air, into an airtight gap part constituted of a spacer body provided so as to surround the circumferential edge part of the outside surface of a face plate and an opposed surface of a lens. CONSTITUTION:A plane-like opposed surface 41 of a lens 4 of an optical lens system 3 is provided in nearly parallel at a prescribed interval on the outside suface of a plane-like face plate 9 on which a fluorescent surface 2 of a cathode ray tube 1 is stuck and formed, and an optical medium 13 whose refractive index is the same as that of the face plate 9 is interposed between the outside surface of this face plate 9 and the plane-like opposed surface 41 of the lens 4. For instance, when a point P of the fluorescent surface is spurred by an electronic beam, and emits beams 10-12 advancing at angles theta1, theta2 and theta3 against an optical axis Z, these beams 10-12 are made incident to the incident surface of the lens 4, namely, the opposed surface 41 as they are at the angles theta1- theta3 against the optical axis Z. |
