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US 6,630,791 B2Granted
Cathode ray tube device that reduces magnetic field leakage
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsYukio Uchida, Tomoaki Iwamoto, Katsuyo Iwasaki
Life of this patent
Estimating the term…
Abstract
Two closed-loop coils are respectively set at the top or the bottom of a cathode ray tube. These two closed-loop coils serves in a pair as a cancel coil. Each closed-loop coil is positioned so as to make an interlinkage with the magnetic field leakage that escapes from the deflection yoke, a part of the closed-loop coil running almost in parallel to the top or bottom edge of an effective display region of a front panel.
Claims9
A cathode ray tube comprising:
- a cathode ray tube that has a front panel with an effective display region contained within the front panel;
- an electron gun that is set inside a neck of the funnel projects electron beams onto an inner surface of the front panel;
- a deflection yoke that is set on the funnel at the neck and deflects the electron beams projected by the electron gun;
- and
- a cancel coil that has at least one closed-loop coil, makes an interlinkage with a magnetic field leakage that escapes from the deflection yoke, and generates a magnetic field in a direction so as to cancel the magnetic field leakage, said closed-loop coil is a one-turn coil that lies in a substantially flat surface and is electrically grounded,
- wherein said closed-loop coil is set at either a first position or a second position, the first position having a part of the closed-loop coil running across the front panel and along a top edge of the effective display region of the front panel, and the second position having a part of the closed-loop coil running across the front panel and along a bottom edge of the effective display region.
3 more elements
A cathode ray tube device comprising:
- a cathode ray tube that has a front panel with an effective display region and a funnel;
- an electron gun that is set inside a neck of the funnel and projects electron beams onto an inner surface of the front panel to perform a raster scan of the effective display region;
- a deflection yoke that is set on the funnel at the neck and deflects the electron beams projected by the electron gun;
- and
- a pair of cancel coils, each including a single turn closed-loop coil which is directly grounded and situated in a plane approximately parallel to an axis of the cathode ray tube, each cancel coil makes an interlinkage with a magnetic field-leakage that escapes from the deflection yoke, and generates a magnetic field in a direction so as to cancel at least a portion of the magnetic field leakage,
- wherein one cancel coil is positioned at a top of the cathode ray tube with a part of the closed-loop coil arranged across a front surface of the front panel and just above a top edge of the effective display region of the front panel, and the other cancel coil is positioned at a bottom of the cathode ray tube with a part of the closed-loop coil arranged across a front surface of the front panel and just below a bottom edge of the effective display region.
3 more elements
Dependencies are inferred from the claim text.