US5444500A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Display device including a correction circuit, and correction circuit for use in a display device
Assignee: US Philips Corp
•
Filing: 1993-11-16
•
Granted: 1995-08-22
•
Expires: 2013-11-16
Abstract
Abstract To improve the sharpness of (video) pictures to be displayed on a display screen of a display device, it is known to use scan velocity modulation. The drawback of scan velocity modulation is that an improvement of the (impression of) sharpness is obtained in given types of video signal/pictures only. By starting from the properties of the display tube when improving the (impression of) sharpness of the displayed picture, a much better improvement can be obtained. Information about the relevant display tube is applied to a correction circuit which also receives a video signal-dependent signal. With reference to these input signals, the correction circuit determines whether and how the video signal is to be corrected so as to obtain an ideal picture on the display screen. Reducing the contrast is a first step of restoring the resolution. Modulating the read clock of the video signal is a second step. Using scan velocity modulation is the last step. The correction circuit determines/computes one clock signal which is applied to a contrast control circuit, a clock modulator and a scan velocity modulator, respectively.
Inventors
- 👤 Hendrik ten Pierick
- 👤 Jan G. Prummel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:03
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/57; H04N5/59; H04N3/00; H04N3/10; H04N3/16; H04N3/26; H04N3/30; H04N3/32
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
154 words
A display device having an input for receiving an input video signal, a video signal processing circuit for processing the input video signal to an output video signal, said video signal processing circuit having an output for applying the output video signal to a display tube of the display device, a deflection unit for deflecting at least one video signal-dependent beam current generated in the display tube, and a correction circuit for correcting the video signal to be displayed, characterized in that the correction circuit has a first input for receiving a signal conveying display tube characteristic data, and a second input for receiving a signal dependent on the input video signal, said correction circuit generating, with reference to the signals received at said first and second inputs, a correction signal to be supplied from an output of the correction circuit which is coupled to a correction input of the video signal processing circuit.
Claim 2
Dependent Claim
154 words
A display device having an input for receiving an input video signal, a video signal processing circuit for processing the input video signal to an output video signal, said video signal processing circuit having an output for applying the output video signal to a display tube of the display device, a deflection unit for deflecting at least one video signal-dependent beam current generated in the display tube, and a correction circuit for correcting the video signal to be displayed, characterized in that the correction circuit has a first input for receiving a signal conveying display tube characteristic data, and a second input for receiving a signal dependent on the input video signal, said correction circuit generating, with reference to the signals received at said first and second inputs, a correction signal to be supplied from an output of the correction circuit which is coupled to a correction input of the video signal processing circuit.
Claim 3
Dependent Claim
71 words
A display device as claimed in claim 1, characterized in that the correction circuit includes a computing unit for determining a beam current measuring signal having a value which corresponds to the beam current to be generated in the display tube, and a comparison unit for comparing the beam current measuring signal with a reference signal, the correction circuit being adapted to generate the correction signal in dependence upon the comparison.
Claim 4
Dependent Claim
40 words
A display device as claimed in claim 1, characterized in that the output of the correction circuit is coupled to a contrast control circuit of the video signal processing circuit for controlling the contrast in dependence upon the correction signal.
Claim 5
Dependent Claim
47 words
A display device as claimed in claim 1, characterized in that the output of the correction circuit is coupled to a read clock of a memory of the video signal processing circuit for modulating the read rate of the video signal in dependence upon the correction signal.
Claim 6
Dependent Claim
49 words
A display device as claimed in claim 1, characterized in that the output of the correction circuit is coupled to a scan velocity modulator associated with the display device for modulating a rate of deflection of said at least one video signal-dependent beam current generated in said display tube.
Claim 7
Dependent Claim
39 words
A display device as claimed in claim 1, characterized in that the correction circuit includes a low-pass filter for generating the correction signal in dependence upon the beam current measuring signal and in dependence upon the display tube-dependent signal.
Claim 8
Dependent Claim
142 words
A correction circuit for correcting a video signal to be displayed in a display device having an input for receiving an input video signal, a video signal processing circuit for processing the input video signal to an output video signal, said video signal processing circuit having an output for applying the output video signal to a display tube of the display device, and a deflection unit for deflecting at least one video signal-dependent beam current generated in the display tube, characterized in that the correction circuit has a first input for receiving a signal conveying display tube characteristic data, and a second input for receiving a signal dependent on the input video signal, said correction circuit generating, with reference to the signals received at said first and second inputs, a correction signal to be supplied from an output of the correction circuit.
Claim 9
Dependent Claim
142 words
A correction circuit for correcting a video signal to be displayed in a display device having an input for receiving an input video signal, a video signal processing circuit for processing the input video signal to an output video signal, said video signal processing circuit having an output for applying the output video signal to a display tube of the display device, and a deflection unit for deflecting at least one video signal-dependent beam current generated in the display tube, characterized in that the correction circuit has a first input for receiving a signal conveying display tube characteristic data, and a second input for receiving a signal dependent on the input video signal, said correction circuit generating, with reference to the signals received at said first and second inputs, a correction signal to be supplied from an output of the correction circuit.
Claim 10
Dependent Claim
71 words
A correction circuit as claimed in claim 7, characterized in that the correction circuit includes a computing unit for determining a beam current measuring signal having a value which corresponds to the beam current to be generated in the display tube, and a comparison unit for comparing the beam current measuring signal with a reference signal, the correction circuit being adapted to generate the correction signal in dependence upon the comparison.
Claim 11
Independent Claim
107 words
A method of correcting a video signal to be displayed in a display device, said method comprising the steps: generating at least one electron beam current in a display tube; processing a received input video signal to obtain an output video signal, said output video signal coupled to modulate the at least one electron beam current; and generating a correction signal for correcting the input video signal, the correction signal being dependent on the input video signal, characterized in that the method further comprises the step: receiving display tube characteristic data, and the step of generating the correction signal is dependent on the display tube characteristic data.
Claim 12
Independent Claim
107 words
A method of correcting a video signal to be displayed in a display device, said method comprising the steps: generating at least one electron beam current in a display tube; processing a received input video signal to obtain an output video signal, said output video signal coupled to modulate the at least one electron beam current; and generating a correction signal for correcting the input video signal, the correction signal being dependent on the input video signal, characterized in that the method further comprises the step: receiving display tube characteristic data, and the step of generating the correction signal is dependent on the display tube characteristic data.
References Cited (Backward Citations)
US3949166A
Cited
US4170785A
Cited
US4549216A
Cited
US4551653A
Cited
US4687973A
Cited
JPS63164765A
Cited
US4982287A
Cited
GB2273425A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-08-21 | 1999-02-20 | 1999-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-08-21 | 2003-02-20 | 2003-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-08-21 | 2007-02-20 | 2007-08-22 | $7700.00 | Window Closed / Lapsed |