KR20010095889A - Flat Color Cothod Ray Tube - Google Patents

Abstract

PURPOSE: A flat CRT is provided to achieve an improved color purity and luminance of CRT by improving the structure of rail and array of electron beam passing through the shadow mask, while increasing productivity of fluorescent screen. CONSTITUTION: A flat CRT comprises a flat panel(1) having a safety glass attached to the front surface of the flat panel, and a fluorescent surface formed at the inner surface of the flat panel; a rail(2) attached to the inner surface of the panel by a frit glass; and a shadow mask(4) supported by the rail, and which discriminates colors. The rail has a longer side with a predetermined thickness in a Z-axis direction, and a shorter side with a thickness in the Z-axis direction which decreases as it goes from the center of Y-axis direction toward upper and lower portions of the shorter side of the rail.

Description

Flat Cathode Ray Tube {Flat Color Cothod Ray Tube}

The present invention relates to a planar cathode ray tube, and more particularly, to a structural improvement of a rail which is a shadow mask support.

In general, a flat cathode ray tube is a device for receiving a video signal converted into an electrical signal and reproducing it into an image. The flat cathode ray tube is used for a monitor or a T.V.

1 is a cross-sectional view showing a conventional planar cathode ray tube, Figure 2 is a plan view showing a shadow mask including a plurality of slots, Figure 3 is a cross-sectional view showing the path of the electron beam in a general planar cathode ray tube.

Referring to this, a conventional planar cathode ray tube will be described as follows.

In the conventional flat cathode ray tube, as shown in FIG. 1, a safety glass is attached to the front surface of the panel 1, and a fluorescent surface 1a coated with phosphors is formed on an inner surface thereof, and a plurality of fine slots 41 are formed on the inner surface thereof. A shadow mask 4 having a slot formed thereon is fixed to a rail 2 attached to the panel to form a panel assembly.

The funnel 5, which is a vacuum bulb, is attached to the rear of the outer panel 1 of the rail 2 by frit glass, and an electron gun 6 is enclosed in the neck portion thereof, and an electron beam is formed in the outer circumference of the neck portion. A deflection yoke 7 for deflecting 8) is provided.

In more detail, as shown in FIG. 2, a horizontal pitch Ph and a vertical pitch Pv are formed between the slot 41 and the slot of the shadow mask 4.

As shown in FIG. 3, the shadow mask 4 is welded to the flat portion 3 of the rail 2 so that a constant distance is maintained between the shadow mask 4 and the inner surface of the panel 1.

In this case, the rail 3 is divided into a long side portion and a short side portion according to the rectangular length of the panel 1, and includes a flat portion 31 having a step.

Operation of the conventional planar cathode ray tube of such a configuration is as follows.

As shown in FIG. 3, the red, green, and blue electron beams 8 projected by the electron gun 6 are deflected in the vertical and horizontal directions by the deflection yoke 7 to form a fine slot ( 41), and landing on the phosphor of the fluorescent surface to reproduce the image.

However, since the distance from the start of deflection of the cathode ray tube to the center of the shadow mask is smaller than the radius of the shadow mask curvature, the red, green, and blue electron beams converge at the shadow mask periphery and fall short of the shadow mask. Can't pass

Therefore, when scanning the electron beam in each slot in a certain order, the color arrangement is uniform because three colors are landed on the phosphor of the same color at the center of the panel 1, but the color arrangement of the electron beam is not constant at the periphery, top, bottom, and corner. not.

That is, the farther from the center, the electron beam 8 cannot be accurately landed on the phosphor, so that the color line and luminance of the cathode ray tube are lowered.

In order to solve this problem, in the conventional shadow mask, when configuring the interval between the slots 41, the horizontal pitch Ph is variable in consideration of the shear stress formed in the slot of the shadow mask, and the vertical pitch Pv. Was kept constant to improve electron beam misalignment.

However, even in this conventional method, the beam arrangement of the periphery with respect to the shadow mask center is improved, but since the electron beam misalignment with respect to the upper and lower portions of the shadow mask remains, the induction of different colors of electron beams landing on the phosphor is reduced, resulting in various color sums. This difficulty, the uniformity of white is poor, the brightness of the cathode ray tube is lowered, the direction rotation and the magnetic field induction is reduced to reduce the quality of the shadow mask.

In addition, since the arrangement of the fluorescent surface is also formed in the same manner as the arrangement of the electron beam, the BM-PH shift margin in the coating step is reduced, thereby decreasing the productivity of the fluorescent surface.

An object of the present invention devised to solve the above problems is to improve the color purity and brightness of the cathode ray tube, and to increase the fluorescent surface productivity.

1 is a cross-sectional view of a typical flat cathode ray tube

2 is a plan view showing a shadow mask including a slot

3 is a cross-sectional view showing a path of an electron beam in a general planar cathode ray tube;

4 is a perspective view showing a combination of a panel, a rail and a shadow mask according to the present invention;

Figure 5 is a perspective view of the present invention short side rail

Fig. 6 is a graph showing the grouping ratio (G / R) according to the thickness of the tube in the short side rail set according to the coefficient value.

<Description of Signs of Main Parts of Drawing>

1: panel 2: rail

3: flat part 4: shadow mask

5: funnel 6: electron gun

7: deflection yoke 41: slot

31 flat portion 8: electron beam

B: coefficient 1a: fluorescent surface

Ph: Horizontal pitch between slots

Pv: Vertical pitch between slots

S: spacing between electron beam centers

Q: the distance between the shadow mask and the fluorescent surface

L: Spacing between fluorescent surfaces at the start of electron beam deflection

According to the present invention, a flat cathode ray tube including a panel, a rail attached to an inner surface of the panel, and a shadow mask supported on the rail to perform color selection, wherein the rail has a constant tube axis (Z axis) It has a thickness in the direction, the short side portion is to provide a flat cathode ray tube, characterized in that formed in the tube axis (Z-axis) direction thickness becomes thinner toward the top and bottom from the longitudinal axis (Y axis) direction center.

The present invention will be described in detail with reference to the accompanying drawings.

4 is a perspective view showing a panel, a rail and a shadow mask of the present invention, Figure 5 is a schematic perspective view showing a short side rail according to the present invention, Figure 6 is a tube axis of the short side rail set according to the value of the coefficient according to the management tolerance It is a graph which shows the relationship between direction thickness and grouping rate (G / R).

As shown in Fig. 4, in the panel assembly of the cathode ray tube in which an image is reproduced, the panel 1 is formed in a plane, and a front surface thereof is attached to safety glass by a curable adhesive, and a fluorescent surface coated with a phosphor on an inner surface thereof. Is formed.

Then, after fixing the long side portion and the short side rail 3 to the rear of the long direction panel 1 with frit glass, the interval between the slots 41 forms a horizontal pitch Ph and a vertical pitch Pv. The long side end of the shadow mask 4 is welded and fixed to the long side flat portion of the rail 2, and the end of the shadow mask short side portion and the short side flat portion 3 of the rail 2 are welded.

Thus, a shadow mask 4 of a thin film formed of an Invar alloy is positioned behind the rail 3, and a constant gap Q is formed between the shadow mask 4 and the fluorescent surface that is the inner surface of the panel.

In this case, in the rail, the long side rail includes a flat portion formed with a step of the same thickness, but the short side rail 2 includes a flat portion 3 formed with a step, as shown in FIG. The same, but the thickness Q in the short axis (Z axis) direction is not the same in the longitudinal axis (Y axis) direction, which is explained in the configuration of the present invention below.

In addition, a rectangular inner shield is attached to the low flat portion of the rail 2 to prevent the electron beam projected from the electron gun from being changed by the geomagnetic field, and a funnel in which the electron gun is enclosed in the neck is placed on the inner surface of the panel. It is fixed with frit glass and a deflection yoke is installed on the outer peripheral surface of the neck portion of the funnel.

When the cathode ray tube of the present invention configured as described above is operated, the image is converted into an electrical signal and transmitted by the transmitting station, and the electrical signal is input to the electron gun of the cathode ray tube.

Then, the electron gun injects red, green, and blue electron beams to the inner surface of the panel in a predetermined order, which is deflected by the deflection yoke at the start of deflection, passes through the inner shield, and only about one fifth of the shadow mask slot (41). ) And land on the phosphor of the phosphor surface.

At this time, the arrangement of the phosphors that emits light is called grouping. When the colors of the electron beams landing on one phosphor are gathered with red and blue around green, the group is called red. It is called a degroup where blue is not gathered.

In addition, the case where the intervals between the red-green, green-blue, and blue-red phosphors are the same is called GR ratio 1, and this arrangement ratio is called G / R, and the calculation formula is as follows.

GR (Grouping) = (1)

Ph: Horizontal pitch of shadow mask

L is the distance between the fluorescent surface and the electron beam deflection point

S: beam seperation

Q: the gap between the shadow mask and the fluorescent surface

Therefore, the grouping ratio of the beam array using the above equation in the 17-inch screen is shown in Table 1 below.

<Table 1>

L ' S L Qm G / R Rate Qm * S / L ' Ph (variable) center 302.80 4.201 231.300 4.404 1.000 0.061 0.240 Diagonal 371.89 4.443 316.41 6.025 1.114 0.072 0.267 Periphery 348.60 4.372 288.67 5.497 1.084 0.069 0.260 Top 329.35 4.306 265.10 5.048 1.054 0.066 0.253

According to Table 1, when the distance from the center of the shadow mask 4, the beam arrangement falls as shown in the G / R magnification.

At this time, when the grouping ratio (G / R), in which the intervals between the phosphors are equally formed in red-green, green-blue, and blue-red colors, is maintained at 1, the color purity, brightness, purity, etc. of the image of the cathode ray tube are maintained. It can be improved to obtain good image quality.

Therefore, in order to improve the beam misalignment, the factor of Equation (1) is changed, but the horizontal pitch (Ph) of the shadow mask must be kept constant, thereby changing the factor of S * Q / L.

However, according to the calculated value of S * Q / L 'in each part in Table 1, S, L, Q in the peripheral portion will have a value different from the center due to the geometric position change.

In addition, in the present invention, the grouping ratio (G / R) should be configured to be 1.0 so as to improve the beam array (to make G / R = 1.0 of equation (1)), so that equation (1) is converted as follows. do.

-Equation (2)

However, when Ph at each point is obtained by Equation (2), the pH value is changed along the horizontal and vertical directions, and the shadow mask 4 is torn due to the shear stress applied to the slot 41.

Thus, the shadow mask 4 is fixed to the rail 2, but the vertical pitch Pv is kept constant, and the horizontal pitch Ph is varied to adjust the arrangement of the slots.

However, only the slot 41 arrangement of the shadow mask 4 as described above still maintains the poor beam arrangement between the center of the panel and the upper and lower parts as in the prior art, and thus the image quality of the cathode ray tube is not improved.

In order to improve the accuracy of the beam arrangement of the cathode ray tube, Equation (2) shows that the distance Q between the shadow mask and the inner surface of the panel can be selectively changed so that it can be variably changed in the vertical direction. Since phosphors are degrouped at, in order to lower G / R according to equation (1), the upper and lower Qs should be lowered.

In this case, the distance between the shadow mask and the inner surface of the panel is variable, so that the inner surface of the panel is formed with curvature, or the panel is adhered with frit glass so that the height of the rail supporting the shadow mask is higher than both ends at the short sides. It is.

However, if only the outer surface of the panel is flat, and the inner surface of the panel is formed with curvature, the luminous properties are poor, and the panel is difficult to be polished, resulting in poor productivity.

Therefore, when the space | interval of the panel inner surface and shadow masks 4 and Q, ie, the short side part height Q of a rail, is changed, Formula (3) is derived.

-Equation (3)

In an embodiment of the present invention, a 17 "flat color cathode ray tube is obtained by using Equation (3) to obtain a Q value such that the electron beam 8 array (G / R) is 1, and the beam array (G / R) is shown in Table 2 below. Same as

<Table 2>

L ' S L G / R Qm (Real) Qm (Ver.) DEF. center 302.80 4.201 231.300 1.000 4.404 4.404 0.000 57.6 308.22 4.224 238.36 1.000 4.485 4.352 0.052 115.1 323.95 4.286 258.38 1.000 4.710 4.216 0.188 172.7 348.60 4.372 288.67 1.000 5.070 4.062 0.342

As shown in the table, the uniaxial thickness Q of the short side of the rail 3 for forming the beam array G / R equal to 1 depends on the length in the longitudinal axis (Y axis) direction, and the relational expression is

Qy = Qo + B * y-expression (4)

Qo: Q value at the center

y: distance away from the center in the longitudinal direction

B (factor):-0.0015

It is expressed as

In this case, the closer the beam array is to 1, the higher the image quality is reproduced. However, the larger the control tolerance considering the effective error in the work process during rail manufacturing, the better the manufacturability. Therefore, the tolerance level is generally the largest within the quality acquisition level. The rail according to the invention should be designed to have a tolerance value.

In addition, since the tolerance of the beam array is normally managed to be within 2% to obtain the desired quality level, the short side of the rail 3 is -0.001 to 0.002 in consideration of the management tolerance as a result of Equation (4) and Table 3. It is molded with the coefficient set to within.

That is, in FIG. 6, the horizontal axis | shaft shows the uniaxial thickness formed according to each count value of the rail short side part, and a vertical axis | shaft is the grouping ratio (G / R) which the cathode ray tube provided with the rail short side part formed with each count value is shown.

Therefore, the long side rail of the cathode ray tube of the present invention is formed in a constant thickness, the short side rail (3) is formed in the tube axis thickness is thinner than the center from the center of the vertical axis to the upper and lower in consideration of the management tolerance.

In addition, even when the phosphor is applied in the same manner as the slot 41 array of the shadow mask 4 during the phosphor coating process, the BM-PH shift margin is increased, so that the production is easy and the productivity of the screen is improved.

As described above, in the planar cathode ray tube, the present invention improves the rail structure and improves the arrangement of the electron beams passing through the side, top, bottom, and diagonal portions of the shadow mask, thereby greatly improving the rudder margin of the beam, thereby improving whiteness. Uniformity and purity, quality of the magnetic field and direction margin of the shadow mask are improved, and the BM-PH shift margin of the phosphor and the shadow mask is increased to increase productivity of the fluorescent surface.

Claims (3)

Panel, A rail attached to the inner surface of the panel, In the planar cathode ray tube comprising a shadow mask which is supported by the rail and performs a color screening function, The long side portion of the rail has a constant thickness in the tube axis (Z axis) direction, the short side portion is a flat cathode ray tube, characterized in that the thickness in the tube axis (Z axis) direction toward the upper and lower portion in the longitudinal axis (Y axis) direction center. The method of claim 1, In the short side portion of the rail, the thickness in the axial direction has a relationship of Qy = Qo + B * y, Qo is the Q value at the center, y is the distance away from the center in the longitudinal axis direction, B is a coefficient Flat cathode ray tube. The method of claim 2, And said coefficient (B) is in the range of approximately -0.0010 to -0.0020.