CN2054240U - Automatic contrast regulator - Google Patents
Automatic contrast regulator Download PDFInfo
- Publication number
- CN2054240U CN2054240U CN 89214294 CN89214294U CN2054240U CN 2054240 U CN2054240 U CN 2054240U CN 89214294 CN89214294 CN 89214294 CN 89214294 U CN89214294 U CN 89214294U CN 2054240 U CN2054240 U CN 2054240U
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- voltage
- contrast
- electron beam
- beam current
- limiting part
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Abstract
The utility model discloses an automatic contrast regulator which is provided with a video signal processing integrated circuit, wherein, luminance signals are controlled by the output of a luminance level control part. The utility model comprises an electron beam current limiting part, a contrast gain control part, a detecting voltage limiting part, and a luminance limiting part, wherein, the contrast gain control part uses a variable resistor to change the detected voltage of the electron beam current limiting part so as to adjust the contrast of the video signal processing circuit; the detecting voltage limiting part clamps the detected voltage at the detecting voltage limiting part; the output voltage of the luminance control part is limited by the luminance limiting part according to the detected voltage of the electron beam current limiting part. The utility model can suitably adjust screen and obtain the three-dimensional screen images with appropriate contrast and color.
Description
The present invention relates to a kind of auto contrast's adjuster, especially relate to the excessive electron beam current on a kind of cathode ray tube (CRT) that can prevent to be added in the color TV set, and adjust on the cathode ray tube vision signal with respect to the adjuster of the contrast of its average level.
In general, used all video signal playback systems all have an automatic brightness limiter circuit, in order to prevent owing to the distortion of the overheated cathode ray tube mask that causes of negative electrode under excessive electron beam current situation and the string credit of colorimetric purity, also in order to placing restrictions on the power loss of system, and prevent that X ray from exceedingly emitting on the cathode ray tube.
This automatic brightness limiter can only limit the DC level of video amplifier circuit according to the electron beam current amount, but good image can not be provided, because it can not automatically adjust this Amplifier Gain according to the composition of vision signal.
Promptly because common auto brightness adjuster can not reset high average picture level (APL) (in other words, control the gain of this video amplifier during high-contrast) vision signal, seem with regard to there being personage's face undue strong or hair seems to be problem dark and that be difficult to distinguish.
In addition, because being used for the integrated circuit of vision signal processing, great majority have monochromatic nature, therefore, the degree of colour saturation and the contrast of signal change pro rata, if only use brightness limiter, the difference of the details of image is difficult to obtain on the screen of high-contrast so, and image can not be reset out as the figure of sending part office that way.
In common automatic brightness limiter, when image is dark,, can reduce high electron beam current because average picture level is low, this causes the raising of the detection voltage that is used for brightness limit, thus the output DC that has improved video amplifier is flat.Therefore, though actual screen is dark since a large amount of electron beam currents flow through the dark image of still can resetting out.
Consider above-mentioned situation, the purpose of this invention is to provide a kind of like this auto contrast's adjuster, in this auto contrast's adjuster, detect the average picture level of vision signal, with restriction maximum electron beam electronic current, and keep suitable contrast level, and under the situation of excessively high contrast, automatically reduce the gain of video amplifier according to average picture level, and the gain that under the situation of low contrast, improves video amplifier, thereby keep suitable contrast gain and playback three-dimensional image.
According to the present invention, a kind of auto contrast's adjuster with vision signal processing integrated circuit is provided, wherein control luminance signal by the output of intensity level control section.This regulator device comprises: an electron beam current restricted part; One contrast gain controlling part is in order to adjust the contrast of vision signal processing integrated circuit by the variable resistance that uses the detected electron beam current restricted part voltage of change; One detects the voltage limit part, in order to should detected voltage clamp to voltage B2, an and brightness limit part limits brilliance control output level partly in order to the voltage according to detected electron beam current restricted part.
Accompanying drawing 1 is a block diagram of the present invention;
Accompanying drawing 2 is circuit diagrams of the present invention;
Now consult accompanying drawing and will do detailed explanation the present invention.
Fig. 1 shows block diagram of the present invention.This adjuster comprises: the electron beam current restricted part 1 that is used to provide electron beam current and detects excessive electron beam current; Detect voltage limit part 2, in order to will be in electron beam current restricted part 1 detected voltage limit for being lower than B2; Contrast gain controlling part 4 is in order to be provided at the detected voltage in part 1 place (as supply voltage) to the contrast controlled quentity controlled variable; Intensity level control section 5, in order to provide brilliance control voltage to common vision signal processing integrated circuit 6, in this integrated circuit 6, the voltage of contrast gain controlling part 4 is provided to the contrast amplifier; And brightness limit part 3, in this part 3, when the control voltage of described contrast gain controlling part 4 fails to be detected by the contrast amplifier of vision signal processing integrated circuit 6 at excessive electron beam current, the output voltage of intensity level control section 5 is descended.
Fig. 2 is a circuit diagram of the present invention.Wherein comprise resistor R 1 in order to the electron beam current restricted part 1 that electron beam current and detected electrons beam electronic current are provided; Contrast gain controller 4 in order to the control contrast comprises resistance R 3 and variable resistance VR1; In order to being that the detection voltage limit part 2 that is lower than B2 comprises diode D1 with detected voltage clamp.
Supply voltage B3 is added to common vision signal processing integrated circuit 6, the variable resistance VR2 that common intensity level control section 5 comprises resistor R 4, R5, adjust for the user, is used to the diode D3 that adjusts the semifixed variable resistor VR3 of high-high brightness and be used for temperature-compensating.And, be arranged between intensity level control section S and the P point, under overcurrent situations in order to the restriction brightness brightness limit part 3 comprise diode D2.
In addition, C
1, C
2And C
3Be in order to removing the capacitor of pulsation, the resistor R 2 of low resistance is in order to when the maximum electron beam electronic current of the high-tension coil by feedback transformer (FBT) is adjusted by variable resistance VR3, beam current.
Put up with its work effect referring now to Fig. 2 and explain above-mentioned the present invention.
At first, consider to be added to the mobility status of the electron beam current on the cathode ray tube, by resistor R 1, R2 and feedback transformer FBT, and the anode of cathode ray tube and cathode system are to ground from power supply B1 for this electron beam current.
At this moment, certain portions of electronics beam electronic current of the R1 that flows through is added to the variable resistance VR1 and the resistor R 3 in order to contrast control of contrast gain controlling part 4, thereby at the A end that after capacitor C2 charging, adds to vision signal processing integrated circuit 6.
Therefore, the voltage that P is ordered descends, and the voltage that adds on the variable resistance VR1 two ends is finally reduced.At this moment, if vision signal processing integrated circuit 6 has such characteristic, promptly the contrast Amplifier Gain in the integrated circuit 6 descends when P point voltage step-down, thereby the amplitude of video output signals is descended, the input voltage that this means A end reduces according to the decline of the voltage at the variable resistance VR1 two ends that are used for contrast control, promptly because the increase of high average picture level electron beam current, electron beam current can be inexcessive owing to the less amplitude of the vision signal on the negative electrode that adds to cathode ray tube like this, and contrast is also compensated to improve visual playback performance a little downwards.
And because vision signal processing integrated circuit 6 has monochromatic character, colour saturation degree like this can change according to the contrast gain, controls contrast and color saturation suitably by described work.
But, for opposite situation, it is the situation of the vision signal of harmonic(-)mean picture level, electron beam current reduces, the voltage at resistor R 1 two ends of electron beam current restricted part 1 can be lowered like this, and the P point voltage improves, and the voltage that is used on the variable resistance VR1 two ends of contrast control also improves.Like this, finally the voltage of the A of integrated circuit 6 end can be enhanced.
In other words, if the vision signal of harmonic(-)mean picture level has improved the voltage of the A end of integrated circuit 6, then the contrast Amplifier Gain also improves, and makes the amplitude of the vision signal on the negative electrode add to cathode ray tube to be enhanced, and has just improved electron beam current.
For the vision signal of harmonic(-)mean picture level, contrast is adjusted to higher value.Like this, three-dimensional image is even dark image also can be reset out with the color saturation of the vision signal that improves this harmonic(-)mean picture level by improving contrast.For the vision signal of low-down average picture level, the voltage that P is ordered improves significantly, but the diode D1 of detected voltage limit part 2 is clamped at voltage B2, and like this, its maximum level is to be determined by voltage B2.Promptly, supply voltage B2 than the higher situation of the supply voltage B3 of vision signal processing integrated circuit 6 under, amplify by the maximum that obtains vision signal, we can obtain image clearly, in other words, under the situation of the unusual vision signal of harmonic(-)mean picture level, make image multiplication reach maximum.
Though the common variable range of contrast amplifier is about 40dB, owing to the voltage on the variable resistance VR1 two ends that are used for contrast control can change on very big scope by being adjusted to average picture level, so the present invention can make full use of the dynamic range of cathode ray tube.
On the other hand, the direct voltage that adds to the B end of integrated circuit 6 can be controlled by the voltage that is provided by common intensity level control section 5, if the voltage that adds to B end by smmothing capacitor C3 provides here, then the DC level of video amplifier improves, thereby makes image bright.
But if this voltage descends, then image is with regard to deepening.In other words, the DC input voitage of the B end of the intensity level control section 5 of the diode D3 that semifixed variable resistor VR3 that has comprised the variable resistance VR2 that uses for the user, used for brilliance control and temperature-compensating are used by supply voltage B3 dividing potential drop being come control integrated circuit 6, like this, the control voltage according to intensity level control section 5 makes that image can be bright or dark.
In addition, the B of vision signal processing integrated circuit 6 end is connected to the P point by the diode D2 of brightness limit part 3, and the voltage of crossing B end when strong when electron beam current reduces to limit brightness like this.Promptly too be higher than the working range of contrast amplifier when electron beam current, the voltage that P is ordered is just lower, makes the input voltage of B end to be reduced diode D2 conducting, thereby limited brightness.
As mentioned above, the present invention can obtain to have the three-dimensional screen image of appropriate level of contrast in action and color by the screen of suitably adjusting arbitrary content, wherein, resistance R 1 restriction and detected electrons beam electronic current, detected voltage is added to the variable resistance VR1 that is used for contrast control, this voltage by diode D1 also by clamp to greater than the supply voltage B2 of B3 terminal voltage, diode D2 is connected between the B end and P point of integrated circuit 6, prevented that like this electron beam current too is higher than the working range of contrast amplifier, become the auto contrast's adjuster that is used to limit the maximum electron beam electronic current and controls the contrast of television video frequency signal.
The present invention is not limited to the above embodiments, explanation by reference the invention described above, the professional and technical personnel will know many improvement and other all embodiment of the present invention of described embodiment, so appending claims improves topped any this class that falls within the scope of the present invention or embodiment.
Claims (2)
1, a kind of auto contrast's adjuster, it is characterized in that it has vision signal processing integrated circuit 6, wherein luminance signal is to be controlled by the output of intensity level control section 5, this adjuster comprises: an electron beam current restricted part 1, be used for the contrast gain controlling part 4 of adjusting the contrast of vision signal processing integrated circuit 6 in order to the variable resistance VR1 of the voltage that changes detected described electron beam current restricted part 1 by using, be used for the control voltage limit part 2 of detected voltage clamp at voltage B2, and the brightness limit part 3 that is used for limiting according to the detection voltage of described electron beam current restricted part 1 output level of brilliance control part 5.
2, according to auto contrast's adjuster of claim 1, it is characterized in that described contrast restricted part 3 is by using diode D2, reduce the output voltage of the intensity level control section 5 that adds to vision signal processing integrated circuit 6 according to the voltage of described detected electron beam current restricted part, thereby limit brightness.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR880019997 | 1988-12-01 | ||
| KR88-19997 | 1988-12-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2054240U true CN2054240U (en) | 1990-03-07 |
Family
ID=19281869
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 89214294 Expired - Lifetime CN2054240U (en) | 1988-12-01 | 1989-07-20 | Automatic contrast regulator |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN2054240U (en) |
| EG (1) | EG18839A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100466059C (en) * | 2004-09-29 | 2009-03-04 | Tcl王牌电子(深圳)有限公司 | Brightness signal limiter circuit based amplification on negative feedback |
| US7701475B2 (en) | 2002-04-05 | 2010-04-20 | Hitachi, Ltd. | Contrast adjusting circuitry and video display apparatus using the same |
| CN102122495A (en) * | 2010-12-29 | 2011-07-13 | 上海申瑞电力科技股份有限公司 | Contrast regulating circuit for liquid crystal display screen |
-
1989
- 1989-07-20 CN CN 89214294 patent/CN2054240U/en not_active Expired - Lifetime
- 1989-07-24 EG EG35189A patent/EG18839A/en active
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7701475B2 (en) | 2002-04-05 | 2010-04-20 | Hitachi, Ltd. | Contrast adjusting circuitry and video display apparatus using the same |
| US7760213B2 (en) | 2002-04-05 | 2010-07-20 | Hitachi, Ltd. | Contrast adjusting circuitry and video display apparatus using same |
| CN1901618B (en) * | 2002-04-05 | 2010-12-15 | 株式会社日立制作所 | Image displaying device |
| US7907134B2 (en) | 2002-04-05 | 2011-03-15 | Hitachi, Ltd. | Contrast adjusting circuitry and video display apparatus using same |
| CN100466059C (en) * | 2004-09-29 | 2009-03-04 | Tcl王牌电子(深圳)有限公司 | Brightness signal limiter circuit based amplification on negative feedback |
| CN102122495A (en) * | 2010-12-29 | 2011-07-13 | 上海申瑞电力科技股份有限公司 | Contrast regulating circuit for liquid crystal display screen |
| CN102122495B (en) * | 2010-12-29 | 2014-09-03 | 上海申瑞继保电气有限公司 | Contrast regulating circuit for liquid crystal display screen |
Also Published As
| Publication number | Publication date |
|---|---|
| EG18839A (en) | 1994-12-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C15 | Extension of patent right duration from 15 to 20 years for appl. with date before 31.12.1992 and still valid on 11.12.2001 (patent law change 1993) | ||
| RN01 | Renewal of patent term | ||
| C17 | Cessation of patent right | ||
| CX01 | Expiry of patent term |