Safe and efficient self-luminous microspheres

• US 4,677,008 A
• Filed: 08/19/1985
• Issued: 06/30/1987
• Est. Priority Date: 08/19/1985
• Status: Expired due to Term

• Current Assignee: Robert D. Webb
• Original Assignee: Robert D. Webb
• Inventors: Webb, Robert D.
• Primary Examiner(s): Herbert, Thomas J.
• Application Number:
  US06/767,106
• Time in Patent Office: 680 Days
• Field of Search: 428/690, 428/325, 428/402.2, 428/35, 428/402, 40/542, 40/545
• US Class Current: 428/34.4
• CPC Class Codes: C09K 11/04 containing natural or artificial radioactive elements or unspecified radioactive elements
• CPC Class Codes: G08B 5/00 Visible signalling systems, e.g. personal calling systems, remote indication of seats occupied
• CPC Class Codes: G09F 13/42 with light sources activated by non-visible radiation cathode ray image or pattern display tubes H01J31/10; lamps with luminescent screens excited by cathode rays H01J63/06
• CPC Class Codes: H01J 65/08 Lamps in which a screen or coating is excited to luminesce by radioactive material located inside the vessel direct conversion of radiation energy from radioactive sources into light G21H3/02
• CPC Class Codes: Y10T 428/131 Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.]
• CPC Class Codes: Y10T 428/252 Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]

Abstract

This invention relates to a means for more efficiently and more safely providing self-luminous lighting devices for use in signs, markers, indicators and the like. Said invention provides self luminosity by means of a plurality of glass microspheres containing both a light emitting phosphor and a radioactive gas. The "soft" emission of electrons from the beta emitting gas can not penetrate the glass wall of the microspheres, thereby constituting no radiation hazard. The containment of the self-luminous system within an envelope which does not pass any radiation prevents the deterioration of nearby organic materials. A further advantage of said invention is that the plurality of individual containment envelopes minimize the escape of radioactive gas in the event of any physical damage to an assembly of such envelopes. A still further advantage of my invention is that the radioactive gas completely surrounds the phosphor particles, thus causing light emission from 100 percent of the surface of said particles.

Claims

1. A self-luminous microsphere comprising:

(a) a gas tight envelope;

(b) a radio-active gas confined within the envelope; and

(c) at least one phosphor particle disposed within the envelope and responsive to the radiation from said gas to become luminous, characterized by said particle being loose within the envelope to thereby receive radiation on all sides.

2. A self-luminous microsphere as set forth in claim 1 wherein the gas is tritium.

3. A self-luminous microsphere as set forth in claim 1, wherein the gas is at a pressure greater than atmospheric pressure.

4. A plurality of microspheres as set forth in claim 1 disposed on a flat surface to act as a sign.

5. A plurality of microspheres as set forth in claim 1 disposed in a transparent binder to form a luminous paint.

6. A self-luminous microsphere comprising:

(a) a gas tight envelope;

(b) a radio-active gas confined within the envelope; and

(c) at least one phosphor particle disposed within the envelope and free to move within the envelope, and responsive to radiation from said radio-active gas to become luminous.