KR900005103Y1 - Focus control circuit of crt - Google Patents

Abstract

No content.

Description

Focus adjustment circuit of CRT

1 is a focusing circuit of the CRT of the present invention.

2 is a waveform diagram of each part of FIG.

* Explanation of symbols for main parts of the drawings

1: vertical deflection circuit 2,4: integrating circuit

3: flyback transformer 5: horizontal output transformer

6: flyback trance focus and anode circuit 7: CRT

C ₁ -C ₆ : Capacitor D1: Diode

L1, L2: Coil R1-R20: Resistance

VR1, VR2: Variable resistor TR1-TR5: Transistor

The present invention relates to a focusing circuit of a cathode ray tube for adjusting a focus voltage around a cathode tube in an electronic deflection type cathode ray tube for converting a traveling direction of an electron beam into a magnetic field, and in particular, it is possible to easily adjust the upper, lower, left and right focus voltages. To a focusing circuit of a CRT.

Conventional focusing circuit of the CRT is to control the vertical and horizontal focus of the CRT by supplying a constant voltage up, down, left and right with respect to the center of the CRT. Since the focus of the vertical and horizontal centers is different, the periphery becomes out of focus, and if the periphery is correctly focused, there is a defect that the center is too hard.

In order to solve such a conventional defect, the present invention not only generates parabolic waveforms in accordance with the sawtooth wave signal and the horizontal pulse signal, but also arbitrarily adjusts the voltages of the parabolic waveforms up, down, left and right, and generates two parabolic waveforms. By mixing, it is possible to adjust the focus in the optimal state throughout the center and the periphery of the CRT, which will be described in detail with reference to the accompanying drawings.

1 is a focus adjustment circuit diagram of the CRT according to the present invention, and as shown therein, the output side of the vertical deflection circuit 1 is passed through the coil L1 and the resistor R1 to the resistor R2 and the capacitor C1. The integrated circuit 2, the capacitor C2, the resistor R3 and the variable resistor VR1 are again connected to the base of the transistor TR1, and the collector of the transistor TR1 is connected to the resistor R6 and the transistor ( Connected to the base of TR2, the collector of transistor TR2 connected to the base of resistor R9 and transistor TR3, while the output side of flyback transformer 3 was coil L2 and capacitor C3. The transistor TR4 together with the emitter of the transistor TR3 through the integrated circuit 4 and through the capacitor C4, the variable resistor VR2 and the resistor R13 again and then through the resistor R11. Is connected to the base of the resistor and the resistor R12, the emitter of the transistor TR4 is connected to the base of the resistor R14 and the transistor TR5, The collector of the transistor TR5 is connected to the capacitors C5, C6, and R19 through the resistor R18 together with the output terminals of the horizontal output transformer 5 through the diode D1 and the resistors R16 and R17. ) And (R20) are connected to the focal grid electrode FG and the anode electrode AG of the CRT 7 through the focal and anode circuit 6 of the flyback transformer.

Referring to the effect of the present invention configured in this way in detail as follows.

When the vertical and horizontal synchronizing signals are output from the vertical deflection circuit 1 and the flyback transformer 3 and a constant power is output from the flat output transformer 2, the vertical synchronizing signals output from the vertical deflection circuit 1 are coiled. The vertical linearity is corrected through L1 to form a sawtooth signal as shown in FIG. 2A. The sawtooth signal is integrated by the resistor R2 and condenser C1 and as shown in FIG. 2B. The parabolic waveform is output according to the period of, and the output parabolic waveform is applied to the base of the transistor TR1 after the DC voltage is removed through the capacitor C2 and the amplitude is adjusted according to the variable of the variable resistor VR1. The amplitude-controlled parabolic waveform is inverted and amplified by transistor TR1, inverted and amplified again by transistor TR2, and then applied to the base of transistor TR3 acting as a buffer and output to its emitter. It is.

As shown in FIG. 2C, the horizontal pulse signal output from the flyback transformer 3 is integrated by the coil L2 and the condenser C3, and as shown in FIG. 2D, in the period of the horizontal pulse signal. The parabolic waveform is converted into a parabolic waveform, and the converted parabolic waveform is removed from the DC voltage through the capacitor C4, and the amplitude is adjusted according to the variable resistor VR2. Since the parabolic waveform is output to the base of the transistor TR4, two parabolic waveforms are mixed and output to the emitter of the transistor TR4, as shown in FIG. 2E, and the output signal is the transistor TR5. Inverted and amplified as shown in 2f through the output to its collector. The signal thus output is applied through the resistor R18 and then to the focus grid electrode FG of the CRT 7 through the capacitor C5 and the resistor R19 of the flyback trans focus and anode circuit 6. The capacitor C5 is applied to the anode electrode AG of the CRT 7 through the capacitor C5 and the resistor R20, the capacitor C6, and the resistor R19.

As a result, at this time, as can be seen from the waveform voltage of FIG. 2f applied to the focal grid electrode FG and the anode electrode of the CRT 7, the peak voltages of the upper and lower sides of the brown tube 7 (the peak value in FIG. 2f) ) Is higher than the center point pressure (lowest part in FIG. 2f) to compensate for the focal lengths of the up, down, left, and right sides due to the longer distance than the center.

In addition, the level of the waveform voltage as shown in FIG. 2f can be adjusted by varying the variable resistors VR1 and VR2.

As described above, the present invention can arbitrarily vary the focus voltage of the CRT up and down, left and right so that the focus can be adjusted optimally throughout the center and periphery of the CRT. have.

Claims (1)

The vertical deflection circuit 1 is connected to the base side of the transistor TR1 via the coil L1 and the ground resistor R1, the integrating circuit 2, the capacitor C2, the resistor R3 and the variable resistor VR1. The collector is connected to the base of the transistor TR3 through the transistor TR2, and the flyback transformer 3 is connected to the integrating circuit 4, the capacitor C4, the variable resistor VR2, and the resistor R13. After passing through, the emitter side of the transistor TR3 is connected to the base side of the transistor TR4, the emitter of the transistor TR4 is connected to the base of the transistor TR5, and the collector of the transistor TR5 Focus adjustment of the CRT, characterized in that it is connected to the anode electrode AG and the focus grid electrode CF of the CRT 7 through the flyback trance focus and the anode arc 6 together with the horizontal output transformer 5 side. Circuit.