JPS6329375B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color picture tube device, and more particularly to a color picture tube device incorporating an electron gun having a composite main lens system consisting of a main electron lens and an auxiliary electron lens.

For example, a conventional shadow mask type color picture tube device incorporating a bipotential type electron gun will be explained with reference to FIGS. 1 and 2.

That is, a panel 2 has a phosphor screen 1 formed on its inner surface made of dot-shaped or band-shaped phosphor layers that emit light in red, green, and blue colors, and a net 4 connected to this panel 2 via a funnel 3. , an electron gun 5 installed in the net 4, a shadow mask 7 for selectively impinging the electron beam 6 from the electron gun 5 onto the phosphor layer of the phosphor screen 1, and a shadow mask 7 installed on the outer wall of the funnel 3. The electron beam 6 is deflected onto the phosphor screen 1 by the deflection device 8, and a color image is reproduced.

The electron gun 5 is connected to the heater 1 as shown in FIG.
1. Consists of a cathode 12, a first grid 13, a second grid 14, a third grid 15, a fourth grid 16, and a convergence electrode 17. The fourth grid 16 and the convergence electrode 17 are connected to a voltage of approximately 20 KV via a valve spacer 18. An anode voltage Eb of 30KV to 30KV is applied to the third grid 15.
A collection voltage Vf of 4KV to 7KV is applied, and a main electron lens is formed between the third grid 15 and the fourth grid 16.

However, since the distance between the aforementioned main electron lens and the phosphor screen is not uniform over the entire surface of the phosphor screen 1, the electron beam 6, which is adjusted to be focused at the center of the phosphor screen 1, is focused at the periphery of the phosphor screen 1. As the electron beam ₆₁ becomes over-focused, and is further subjected to deflection aberration due to deflection, the beam spot is significantly distorted, promoting the above-mentioned over-focusing and producing a large halo.

An effective method for reducing such over-focusing at the periphery of the phosphor screen 1 is the dynamic focus method, in which, for example, the voltage applied to the third grid 15 is changed to reduce the focus of the electron beam from the main electron lens onto the phosphor screen 1. There is a method to eliminate overfocusing at the periphery of the electron beam, but in a bipotential electron gun as shown in FIG. 2, a main electron lens is formed between the third grid 15 and the fourth grid 16. It is necessary to further superimpose a dynamic focus voltage on the focusing voltage Vf of about 4KV to 7KV that forms this main electron lens, which has a large effect on the characteristics of the main electron lens, causing deviations in static convergence, etc. can no longer be ignored, and about
Since a relatively high voltage of 4KV to 7KV is applied, it is difficult from a circuit perspective to superimpose a dynamic focus voltage on the third grid 15. This applies not only to the bipotential electron gun mentioned above, but also to the unipotential electron gun,
Periodic electron guns have similar drawbacks.

The present invention has been made in view of the various drawbacks of the conventional color picture tube devices, and provides a color picture tube device that can focus electron beams almost uniformly at the center and periphery of a phosphor screen. is intended to provide.

Next, one embodiment of the color picture tube device of the present invention will be described with reference to FIGS. 3 to 6.

That is, Fig. 3 is a diagram of a color picture tube device as seen by cutting a rectangular panel along the vertical axis Y-Y'. A panel 22 on which a phosphor screen 21 consisting of a layer is adhered, a net 24 connected to this panel 22 via a funnel 23, an electron gun 25 housed in this net 24, and this electron gun 2.
5 selectively directs the electron beam 26 from the phosphor screen 2
Shadow mask 27 to be projected onto the phosphor layer of No. 1
and a deflection device 28 attached to the outer wall of the funnel 23. The deflection device 28 deflects the electron beam 26 vertically and horizontally onto the phosphor screen 21 to reproduce a color image.

As shown in FIG. 4, the electron gun 25 includes a heater 31, a cathode 32, a first grid 33, a second grid 34, a third grid 35, two fourth grids 36 ₁ , 36 ₂ , a fifth grid 37, It consists of a sixth grid 38 and a convergence electrode 39, and the sixth grid 38 and the convergence electrode 39
Approximately 20KV through valve spacer 40
An anode electrode voltage Eb of 30 KV is applied, the fifth grid 37 and the third grid 35 are connected by a conductor 41, a first focused voltage Vf of about 4 KV to 7 KV is applied, and the two fourth grids 36 ₁ , 36 ₂ have second focusing voltages Vsf ₁ and Vsf ₂ of about 500V to 700V, respectively.
A vertical dynamic focus voltage 42 and a horizontal dynamic focus voltage 43, which will be described later, are applied so as to be superimposed on the second grid 3.
4 is applied with approximately 500V to 700V, the first grid 33 is applied with a ground potential, and the cathode 32 is applied with approximately 100V to 150V, and an electron beam from the triode consisting of the cathode 32, the first grid 33, and the second grid 34 is applied. The third
a unipotential electron lens (auxiliary electron lens) formed by the two fourth grids 36 ₁ , 36 ₂ and the fifth grid 37; and a unipotential electron lens (auxiliary electron lens) formed by the fifth grid 37 and the sixth grid 38. It has a composite main lens system consisting of a bipotential electron lens (main electron lens).

In such an electron gun 25, the voltages of the other electrodes except for the two fourth grids 36 ₁ and 36 ₂ are set to the same conditions, and the dynamic focuses 42 and 43 are
, connect the fourth grids 36 ₁ and 36 ₂ ,
When the second focusing voltage is applied and the second focusing voltage is lowered, the overall focusing characteristic of the electron gun becomes overfocused, and on the contrary, the fourth grid 36 ₁ , 36 ₂
When the voltage is increased, the overall focusing characteristics of the electron gun become insufficiently focused.

Using this characteristic, one fourth grid 36 ₁
Then, a second focused voltage Vsf ₁ consisting of about 500 V to 700 V direct current is applied from a dynamic focus voltage generator along a voltage curve 46 from 0 V to +200 V in synchronization with the vertical deflection curve 45 as shown in FIG. The changing dynamic focus voltage 42, i.e. the vertical periphery of the phosphor screen 21, i.e. 45 of the curve 45.
In a and 45b, the voltage superimposed on the second focusing voltage Vsf ₁ is +200V, and the vertical characteristics of the electron gun are brought into an insufficiently focused state, so that the electron beam 26 ₁ , 26 ₂ to focus the center of the phosphor screen 21, that is, the curve 45.
In 45c, the voltage superimposed on the second focusing voltage Vsf ₁ becomes 0V, and the overall focusing characteristic of the electron gun becomes an overfocused state, so that the electron beam 26 is focused at the center of the phosphor screen 21.

In addition, the other fourth grid ₃₆₂ has about 500V to
A second focused voltage Vsf ₂ consisting of 700V DC is applied from 0V to + from the dynamic focus voltage generator in synchronization with the horizontal deflection curve 47 as shown in FIG.
The dynamic focus voltage 43 that changes along the voltage curve 48 up to 100V, that is, the voltage superimposed on the second focusing voltage Vsf ₂ at the horizontal peripheral edge of the phosphor screen 21, that is, at 47a and 47b of the curve 47, +
100V, the horizontal characteristics of the electron gun become insufficiently focused, and the electron beam is focused at the horizontal edge of the phosphor screen (not shown), and at the center of the phosphor screen 21, that is, at 47c of the curve 47.
The voltage superimposed on the second focusing voltage Vsf ₂ becomes 0V,
The overall focusing characteristic of the electron gun is such that the electron beam 26 is in an overfocused state, and the electron beam 26 is focused at the center of the phosphor screen 21.

As mentioned above, since separate dynamic focus voltages synchronized with both vertical and horizontal deflections are applied to the two fourth grids 36 ₁ and 36 ₂ of the auxiliary electron lens of the electron gun, the characteristics of the main electron lens are does not change, and therefore only the focusing of the electron beam can be made almost uniform over the entire surface of the phosphor screen without causing any deviation in static convergence.

Furthermore, since a third grid 35 to which a relatively high voltage of about 4KV to 7KV is applied is interposed between the second grid 34 and the fourth grid 36, the two fourth grids 36 ₁ and 36 ₂ are Changes in voltage have no effect on cut-off characteristics.

In the embodiment described above, two fourth grids 3
An example is shown in which second focusing voltages Vsf ₁ and Vsf ₂ of approximately 500V to 700V are superimposed on 6 ₁ and 36 ₂ , respectively.
I explained Vsf ₁ and Vsf ₂ as separate voltages, but
This may be the same voltage, or it is also possible for both second focusing voltages Vsf ₁ , Vsf ₂ to be set to other voltages, for example 0V. In the present invention, a voltage with or without direct current superimposed is simply referred to as a dynamic focus voltage. Furthermore, the dynamic focus voltage 42 that is changed in synchronization with the vertical deflection curve 45 is not limited to the waveform and voltage difference as shown in the curve 46, but is similarly changed in synchronization with the horizontal deflection curve 47. The dynamic focus voltage 43 is not limited to the waveform and voltage difference as shown in the curve 48, and of course, it is possible to use a voltage depending on the color picture tube device.

As described above, according to the color picture tube device of the present invention, it is possible to always obtain good focusing of the electron beam at the center and periphery of the phosphor screen, and as a result,
Since clear images can always be reproduced on the phosphor screen, its industrial value is extremely great.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of a conventional color picture tube device, FIG. 2 is a simplified cross-sectional view of an electron gun incorporated into the color picture tube device of FIG. 1, and FIG. FIG. 4 is a simplified cross-sectional view of an electron gun incorporated in the color picture tube device of FIG. 3, and FIG. 5 is a diagram showing a dynamic focus that changes along the vertical deflection. FIG. 6 is a curve diagram schematically showing changes in voltage. FIG. 6 is a curve diagram schematically showing changes in dynamic focus voltage along horizontal deflection. 5, 25... Electron gun, 13, 33... 1st grid, 14, 34... 2nd grid, 15, 35
... 3rd grid, 16, 36 ₁ , 36 ₂ ... 4th
Grid, 17, 39...convergence electrode,
37...5th grid, 38...6th grid.

Claims (1)

[Claims] 1. A panel having a phosphor screen formed of a phosphor layer that emits red, green, and blue colors upon impact with an electron beam on its inner surface, a net connected to the panel via a funnel, and a In a color picture tube device, the electron gun is provided with at least a third grid, two fourth grids, and a third grid, and a deflection device mounted on the outer wall of the funnel. The compound lens system includes an auxiliary electron lens formed by 5 grids, and a main electron lens formed by 5th and 6th grids, and each of the two 4th grids is provided with the A color picture tube device characterized in that a dynamic focus voltage that changes in synchronization with horizontal and vertical movement of an electron beam is separately applied.