LCD-CRT hybrid image tube

• US 5,598,053 A
• Filed: 03/20/1995
• Issued: 01/28/1997
• Est. Priority Date: 03/20/1995
• Status: Expired due to Fees

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Landel, Kevin L., Johnson, John L.
• Primary Examiner(s): O'Shea, Sandra L.
• Assistant Examiner(s): Patel, Ashok
• Application Number:
  US08/409,463
• Time in Patent Office: 680 Days
• Field of Search: 313/364, 313/441, 313/418, 313/408, 313/495, 359/36, 359/40, 359/83, 348/790, 348/761, 348/766, 348/791, 348/805, 345/87, 345/38
• US Class Current: 313/364
• CPC Class Codes: H01J 2229/8926 Active components, e.g. LCD's, indicators, illuminators and moving devices
• CPC Class Codes: H01J 29/89 Optical or photographic arrangements structurally combined or co-operating with the vessel H01J29/866 and H01J29/868 take precedence
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells

Abstract

An LCD projection system, located within a standard color CRT, is used to oject toward the screen decay stimulation patterns that vary dynamically from one frame to the next for each pixel based on the video signals received from external sources. This controls the output light intensity of the phosphors that are excited by a single electron gun. This system eliminates the three-electron-gun configuration of the standard CRT as well as the requirement of a shadow mask. What results is a CRT that is more rugged, easier to manufacture and that produces brighter and sharper images on its screen.

Claims

1. An LCD-CRT hybrid image tube, said tube comprising:

a screen comprised of a plurality of pixels, each of said pixels being made of a phosphor dot triplet, a means for exciting said phosphor dots, a first radiation source for emitting decay stimulation spectra toward said screen;

an LCD array positioned between said first source and said screen, said array being suitable for receiving video signals from externally and, in response thereto, transmitting decay patterns to said phosphor dots and a re-imaging lens, said re-imaging lens being placed between said array and said screen for re-imaging the decay patterns on said screen, thereby controlling the intensity of the visible light output of said dots.

2. An image tube as set forth in claim 1, wherein said tube further comprises a plurality of registration detectors, at least one of said detectors being located at one corner of said screen, said detectors being capable of monitoring the positions of said patterns on said screen and producing error signals when said patterns move out of the perimeters of said screen.

3. An image tube as set forth in claim 2, wherein said tube still further comprises a plurality of actuators, said actuators being coupled between said detectors and said array to manipulate the spatial orientation of said array in response to error signals received from said detectors.

4. An image tube as set forth in claim 3, wherein said exciting means is an electron gun positioned to illuminate said screen.

5. An image tube as set forth in claim 4, wherein said screen further comprises quenching areas, said areas being interspersed with said pixels in a given pattern to provide edge enhancement to any image resulting on said screen.

6. An image tube as set forth in claim 5, wherein said tube still further comprises a flood illuminator positioned to illuminate said quenching areas, said illuminator being capable of emitting radiation of suitable frequency to cause said areas to become dark upon being illuminated thereby.

7. An image tube as set forth in claim 6, wherein said flood illuminator comprises a second radiation source for emitting the quenching radiation and a condensing lens positioned between said second source and said quenching areas.

8. An image tube as set forth in claim 7, wherein an optical spectral filter coating is applied to the exterior of said screen to prevent entrance into said tube of unwanted radiation of a given frequency.

9. An image tube as set forth in claim 5, wherein said first radiation source emits radiation of proper frequency to darken said quenching areas.