Electric lamp and discharge devices – Cathode ray tube – Envelope
Patent
1992-05-22
1994-05-17
Yusko, Donald J.
Electric lamp and discharge devices
Cathode ray tube
Envelope
313110, 313113, 359197, 359201, 359212, 359225, 348196, 348205, H04N 574
Patent
active
053131371
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to display devices and in particular, to display devices which will produce high resolution displays.
The modern cathode ray tube television receiver with normal sized screen, provides a clear, sharp, bright and flicker-free picture. However, particularly with colour televisions, it is not possible to scale the display down smaller than about five inches, without unacceptable loss of resolution. This problem arises from the cathode ray tube design, in which three guns direct electron beams at an array of triads of phosphor dots (red, green and blue) which are deposited on the inside of the cathode ray tube screen. A shadow mask in the form of a fine mesh or grid is required to ensure that each beam only falls upon and excites the corresponding coloured dot of each triad. There is a limit to the degree to which this system may be reduced in size and hence the only way to reduce the size of the picture beyond that limit is to reduce the number of triads and consequently the resolution.
SUMMARY OF THE INVENTION
The present invention provides a display which will produce a small area high resolution picture. While this invention is particularly advantageous with colour displays, it also applies to monochrome displays.
According to one aspect of the present invention a display device comprises; a cathode ray tube including an electron gun, a strip of phosphor, means for focusing a beam of electrons emitted from the gun onto the strip of phosphor, means for scanning the beam of electrons along the strip of phosphor and means for modulating the beam of electrons emitted from the gun and thus the excitation of the strip of phosphor to provide a linear display; and optical scanning means for viewing successive images of the linear display in axially aligned juxtaposed relationship to produce a two dimensional display, characterised in that the optical scanning means includes a first mirror mounted for planar vibrational movement, a transducer for vibrating the mirror, a second mirror mounted parallel to the first mirror and means for focusing the image of the linear display at an angle onto the first mirror so that it is reflected onto the second mirror and back onto the first mirror.
With the above device, the only limits on resolution in the direction along the strip of phosphor will be the particle size of the phosphor and the focus of the electron beam in that direction, and resolution in the direction transverse to the phosphor will depend on the rate of scanning of the electron beam along the strip of phosphor and the rate of movement of the mirror. Very high resolution small area displays may consequently be produced.
According to a preferred embodiment, three strips of phosphor, one red, one blue and the other green, are provided parallel to one another on the cathode ray tube. Three beams of electrons are scanned across these strips to provide three separate linear displays, which are then combined by optical means and focused on to the first moving mirror to produce a full colour picture. As the image produced by the phosphors is not viewed directly, the strips of phosphor may be spaced relatively widely and consequently there will be no problem in focusing the three electron beams sufficiently to avoid interference. There is therefore no need for a shadow mask and none of the limitations on resolution of the conventional colour television technology will apply.
According to one embodiment of the invention, the second mirror is stationary and as the image of the linear display is reflected from the second mirror angular deflection due to vibration of the first mirror is equal to twice the angular movement of the mirror. Preferably, the mirrors are arranged such that the image will be reflected backwards and forwards several times between the mirrors, before emerging from the optical scanning means, the angular deflection being increased by twice the angular movement of the mirror on each subsequent reflection from the vibrating mirror. Conseque
REFERENCES:
patent: 2173476 (1939-09-01), Goldmark
patent: 3532425 (1970-10-01), Silverberg
patent: 3612642 (1971-10-01), Dostal
patent: 4931786 (1990-06-01), Selby
Patel Nimesh
Yusko Donald J.
LandOfFree
Display devices does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Display devices, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Display devices will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-879678