JP2002367841A - Flyback transformer - Google Patents

Abstract

(57) [Problem] To improve focus performance and improve image quality even if a CRT screen is enlarged and flattened. SOLUTION: A third focus voltage adjusting variable resistor 6c and a resistor r ₉ for adjusting the focus at a voltage different from the first and second focus voltages for adjusting the focus at the center of the screen and the periphery of the screen. Is provided, a new electron lens is additionally provided in the CRT gun, and a third focus voltage is supplied to a third focus electrode newly provided in the CRT gun unit, thereby finely tracing the trajectory of the electron beam. It is possible to control and improve the focus performance and the image quality of the CRT screen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flyback transformer for supplying a necessary DC voltage to each electrode of a television receiver, a display monitor device, and the like.

[0002]

2. Description of the Related Art In recent years, as display monitor devices (hereinafter referred to as "monitors") and television receivers (hereinafter referred to as "televisions") have become larger, a cathode ray tube (hereinafter referred to as "CRT") as a screen display unit has been developed. A technique that superimposes a horizontal and vertical cycle parabolic voltage on a DC focus voltage to obtain optimum focus over the entire display screen of a CRT in order to obtain optimal focus performance in order to improve image quality of a screen. Was thought. Then, at most two focus voltages are taken out from a flyback transformer that supplies a necessary voltage to the CRT and supplied to at most two focus electrodes of the CRT, respectively. For the purpose of having an optimum focus performance, a parabola voltage synchronized with the horizontal period and the vertical period of the scanning line is superimposed and the focus is optimally adjusted to obtain the optimal focus of the CRT.

[0003] The configuration of a conventional flyback transformer will be described below with reference to FIG. As shown in FIG.
A conventional flyback transformer includes a primary coil 2 wound around an iron core 1, a secondary coil 3 for supplying an anode voltage and a focus voltage necessary for a CRT, and a diode 4 to a secondary coil 3 from a secondary coil 3. And a focus pack unit 5 that divides the rectified DC voltage by a resistor and supplies an appropriate voltage to a focus voltage input unit and the like of the CRT. In order to obtain the focus, two variable resistors 6a and 6b for adjusting the focus voltage are provided, and the structure is such that a DC focus voltage or a focus voltage in which a parabolic voltage is superimposed on the DC voltage can be supplied to the CRT. are doing.

[0004]

However, in recent years, a flat screen has been required in addition to an increase in the size of a CRT screen, and the flyback circuit structure and the focus electrode structure of the CRT as described above have been required. Then, there is a limit to further improving the focus performance, and it is necessary to further improve the focus adjustment performance.

To increase the size of the screen, electrons are emitted from the cathode of the CRT gun, the trajectory of the electrons is electrically adjusted, and the electrons are accurately applied to each of the phosphor-coated dots arranged on the CRT tube surface. In a CRT system monitor or a television which obtains an image by using a CRT, it is difficult to adjust the trajectory of the CRT due to an increase in the distance between the cathode and the screen of the CRT.

The flattening of the screen will be described with reference to an example in which the screen is not flattened in FIG. 6A and a flattened example in FIG. 6B. As shown in FIG.
Since the screen is flattened by increasing the radius of curvature of the T screen, the incident angle 9b when the electron beam 8 protruding from the CRT cathode electrode 7 reaches the screen is
The incident angle 9a in the case of FIG. 6A, which is not flattened, is smaller than the incident angle 9a.
The deviation Lb of the arrival position at the dot-shaped photosensitive portion arranged on the RT tube surface is larger than the similar deviation La in the case of FIG. 6A, deteriorating the focus performance and deteriorating the image quality. The larger the CRT is, the larger the problem becomes.

An object of the present invention is to provide a flyback transformer capable of improving focus performance and improving image quality even when a CRT screen is enlarged and flattened.

[0008]

According to a first aspect of the present invention, there is provided a flyback transformer for outputting an anode voltage and a screen voltage to a cathode ray tube.
A first focus voltage for dividing the DC voltage output from the secondary coil side to adjust the focus mainly at the center of the screen of the CRT, and a second focus voltage for adjusting the focus at the periphery of the screen of the CRT. A focus voltage and a variable third focus voltage different from the first and second focus voltages are output.

According to a second aspect of the present invention, there is provided a flyback transformer.
The flyback transformer according to claim 1, wherein the third focus voltage generation and output unit is provided as an external accessory.

According to a third aspect of the present invention, there is provided a flyback transformer.
The first, second, and third focus voltage generation and output units are provided as external accessories.

According to the structure of the present invention, the focus is adjusted by the third focus voltage different from the first and second focus voltages for adjusting the focus at the center portion and the peripheral portion of the screen of the CRT. The trajectory of the electron beam can be finely controlled, and the focus performance and the image quality of the CRT screen can be improved even if the CRT screen is enlarged and flattened.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of a flyback transformer according to the first embodiment of the present invention. In FIG. 1, 1 is an iron core, 2, 1
2 is a primary coil, 3 is a secondary coil, 4 is a diode, 5
Is a focus pack unit built in the flyback transformer, 6a is a first focus voltage adjusting variable resistor, 6b
Is a second focus voltage adjustment variable resistor, 6c is a third focus voltage adjustment variable resistor, 11 is a variable resistor, r ₁
~r _7, r ₉ are resistors, C ₁ -C ₃ capacitors, t ₁ ~
t ₉ is a terminal.

As shown in FIG. 1, a flyback transformer according to the present embodiment has a winding 1 wound around an iron core 1.
A secondary coil 2, a secondary coil 3 for supplying an anode voltage, a focus voltage, and the like necessary for the CRT; And a focus pack section 5 for supplying an appropriate voltage. In order to obtain the optimum focus over the entire display screen of the large-sized CRT, two focus voltage adjusting variable resistors 6a and 6 are provided in the focus pack unit 5 as in the conventional example.
b, a DC focus voltage (first focus voltage) for adjusting the focus at the center of the screen of the CRT
The V _2, and supplies the focusing voltage (second focus voltage) V ₄ obtained by superimposing the parabolic voltage to a DC voltage in order to adjust the focus of the screen's peripheral portion in CRT. Further, a third focus voltage V different from the first and _second focus voltages V ₂ and V ₄ is provided in the focus pack unit 5.
To supply ₅ to the CRT is provided with a third focus voltage adjusting variable resistor 6c and resistor r _9.

In FIG. 1, a terminal t₁, T_TwoIs a flyer
Input terminal of the transformer _TwoIs it a TV set
DC voltage is supplied from the₁To flyback voltage
(Primary voltage) occurs. This flyback voltage is
Induced on the output side of the coils 12 and 3 by the magnetic coupling of the
It is. Terminal t of coil 12_Three, T_FourBetween the TV set
Supplied to Terminal t_Five, T₆, T₇Is the ground voltage
Connected. Terminal t₈Is connected to ABL terminal of TV set
(The current supplied to the anode electrode of the CRT is
t₈From). Terminal t₉Is the second form of the CRT
To overlap the focus voltage supplied to the focus electrode
Terminal to input the parabolic waveform voltage of
You.

V ₁ is an anode voltage which is output to the anode of the CRT. V ₂ , V ₄ , and V ₅ are first, second, and third focus voltages, respectively, supplied to the CRT. V ₃
Is a screen voltage, which is used as a CRT screen, that is, a voltage for adjusting brightness, through a circuit of the TV set.
Supplied to The voltage for adjusting the brightness of the CRT is
Slightly different order by the screen voltage V ₃ to be output from the flyback transformer to match the CRT in order to fine tune the variable resistor 11 is provided.

In this embodiment, the first focus voltage V for adjusting the focus in the vertical and horizontal directions of the CRT is used.
₂ and in addition a second focus voltage V _4, there is a third focus voltage V ₅ to adjust the focus of the screen peripheral portion.
These waveforms are shown in FIG. Third focus voltage V ₅
Is set to a voltage lower than the anode voltage V _{1 and} higher than the first and second focus voltages V ₂ and V ₄ . C
Focus electrode of the RT has been the role of the lens narrowing the electron beam and supplying a third focus voltage V ₅ of the CRT, compared with the supply no CRT, the divergence of the electron beam reaching the screen's peripheral portion And control the focus around the screen.

Since the focus voltages V ₂ , V ₄ , and V ₅ are slightly different in the just-focused voltage for each CRT, the variable resistors 6a, 6b, and 6c are provided on the flyback transformer side that supplies the voltages. Provided so that fine adjustment can be made according to the CRT. To adjust these voltages, the CRT is incorporated into a TV set, and the variable resistors 6a, 6b, 6c are appropriately adjusted while viewing the screen.

As described above, according to the first embodiment,
First, the third focus voltage adjusting variable resistor 6c and resistor r ₉ for adjusting the focus at different voltages provided to the second focus voltage V _2, V _4, newly in the CRT cancer Add constituting an electron lens, by supplying to the third focusing electrode provided newly the third focus voltage V ₅ of the CRT gun unit can finely control the trajectory of the electron beam. Therefore, even if the CRT screen is enlarged and flattened, the focus performance and the CRT
It is possible to safely and inexpensively improve the image quality of the screen.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a circuit diagram showing a configuration of a flyback transformer and accessory parts according to the second embodiment of the present invention. In FIG. 3, 10a focus pack portion to be connected to an external flyback transformer, r ₁₀ is the resistance, the same reference numerals are given to portions corresponding to other Figure 1, the description thereof is omitted.

[0020] In the second embodiment, the third focus voltage adjusting variable resistor 6c and resistor r ₉ for supplying a third focus voltage V ₅ of the CRT, the flyback transformer outside the focus pack This is housed in the unit 10a, and the circuit configuration is basically the same as that of FIG. Therefore, the secondary coil 3 of the flyback transformer
DC voltage rectified through the diode 4 and the like from and supplied to the outside of the focus pack portion 10a, the focus voltage input section of the CRT, only the third focus voltage V ₅ is supplied from the focus pack unit 10a, Other voltages are supplied from the focus pack unit 5 in the flyback transformer as in FIG. Incidentally, the anode voltage by the third focus voltage V ₅ is CRT specifications V
Because be set lower than ₁ is required, in FIG. 2, by the resistance r ₁₀ even when the variable resistor 6c came to upper limit is set, the voltage of only focus voltage V ₅ due to the resistance r ₁₀ anode It is lower than the voltage V _1.

Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a circuit diagram showing a configuration of a flyback transformer and accessories in the third embodiment of the present invention. In FIG. 4, 10b focus pack portion to be connected to an external flyback transformer, r ₁₀ is the resistance built into the flyback transformer, the same reference numerals are given to portions corresponding to other Figure 1, their description Is omitted.

In the third embodiment, the configuration of the focus pack unit 5 built in the flyback transformer in FIG. 1 is housed in an external focus pack unit 10b that is not integrated with the flyback transformer. The circuit configuration is basically the same as that of FIG. Therefore, the DC voltage rectified from the secondary coil 3 of the flyback transformer via the diode 4 and the like is supplied to the external focus pack unit 10b, and the focus voltage input unit of the CRT receives the first voltage from the focus pack unit 10b. , Second and third focus voltages are supplied.

It is needless to say that the same effects as those of the first embodiment can be obtained by the above-described second and third embodiments.

In FIGS. 1, 3, and 4, whether the focus pack unit is built in the flyback transformer or not.
Although there is a difference between whether it is provided outside or not, if it is built-in, the flyback transformer will need to be high-voltage and the flyback transformer will be large, including the insulation, but the price increase will be suppressed. The insulation can be removed inside the flyback transformer. If provided outside, it is expensive and requires insulation of the external focus unit, but it is possible to prevent the flyback transformer from becoming large.

[0025]

As is apparent from the above description, according to the present invention, the third focus voltage different from the first and second focus voltages for adjusting the focus at the center and the periphery of the screen of the CRT. The focus can be adjusted by adjusting the trajectory of the electron beam finely, and even if the CRT screen is enlarged and flattened, the focus performance and the image quality of the CRT screen can be improved safely and inexpensively. It is.

[Brief description of the drawings]

FIG. 1 is a diagram showing a flyback transformer according to a first embodiment of the present invention.

FIG. 2 is a waveform chart in the flyback transformer according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a flyback transformer and accessories according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a flyback transformer and accessories according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a conventional flyback transformer.

FIG. 6 is a diagram showing a trajectory of a CRT electron beam for explaining a conventional problem.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Iron core 2 Primary coil 3 Secondary coil 4 Diode 5 Focus pack part 6a Variable resistance for focus voltage adjustment 6b Variable resistance for focus voltage adjustment 6c Variable resistance for focus voltage adjustment 7 CRT cathode electrode 8 Electron beam (trajectory) 9a Incident angle of electron beam on CRT tube surface 9b Incident angle of electron beam on CRT tube surface 10a Focus pack unit 10b Focus pack unit

Claims (3)

[Claims] 1. A flyback transformer for outputting an anode voltage and a screen voltage to a cathode ray tube, wherein the flyback transformer divides a direct current voltage output from a secondary coil side and mainly adjusts a focus of a central portion of a screen of the cathode ray tube. A first focus voltage, a second focus voltage for adjusting a focus of a peripheral portion of the screen of the cathode ray tube, and a variable third focus voltage different from the first and second focus voltages. A flyback transformer characterized by: 2. The flyback transformer according to claim 1, wherein the third focus voltage generation and output unit is provided as an external accessory. 3. The flyback transformer according to claim 1, wherein the first and second and third focus voltage generation and output units are provided as external accessories.