JPS5845775B2 - How to expose the fluorescent surface of a color cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluorescent surface of a color cathode ray tube having a fluorescent surface formed by disposing a light absorption layer between striped three-color phosphor elements and a slot-shaped shadow mask. The present invention relates to a method of exposing a fluorescent surface, particularly to a method of exposing a fluorescent surface when forming a light absorbing layer.

Recently, a so-called black stripe type fluorescent surface 2, which has a light absorption layer 1 arranged between three-color phosphor elements of red, green, and blue, as shown in Fig. 1, has been widely used. It is starting to be adopted.

When forming a light absorption layer on such a black stripe type fluorescent surface, the following exposure method is widely used.

That is, FIG. 2 is a schematic cross-sectional view for explaining the method of fluorescing the fluorescent surface, as seen in the cross section in the arrangement direction of the three-color phosphor elements R, C, and B, and shows that the light absorbing layer is not formed. face
After forming a photoresist film 4 on the inner surface of the plate 3, a slot-type shadow mask 5 as shown in FIG.
is installed at a fixed position on the inner surface of this face plate 3,
A long linear light source 6 is arranged in a direction perpendicular to the plane of the paper.

The light from this linear light source 6 is used to expose the photoresist film 4 through the aperture 7 of the slot-type shadow mask 5. At this time, the trajectory of the exposure light beam is completed to complete the red and green colors when the cathode ray tube is in operation. , the position of the linear light source 6 for performing exposure corresponding to the three-color phosphor elements R2G and B by simulating the trajectory of the three-color blue electron beam r p g s b
Switch as shown in the figure and perform exposure sequentially from three different positions.

In addition, S in the figure indicates the adjacent light source position g, b interval, and rj
This is the distance between g, and is usually set equal or close to equal.

In this way, three exposure areas are formed for every 71 openings of the slot-type shadow mask 5.

Next, the reason why a linear light source is used to expose a fluorescent surface using a slot type shadow mask will be explained with reference to FIG.

FIG. 3 is a schematic sectional view for explaining the method of exposing the phosphor surface, taken in a cross section perpendicular to the arrangement direction of the three-color phosphor elements R, G, and H.

Since the slot-type shadow mask 5 has a non-light-transmitting bridge portion 8 between the apertures 7 and the adjacent apertures 7, when exposure is performed using a small light source such as a point beam, the bridge portion Insufficient light reaches the photoresist film 4 behind the photoresist layer 8, and an uninterrupted aperture is formed on the light absorbing layer.

Therefore, the elongated linear light source 6 is installed in the longitudinal direction of the opening 7 of the slot-type shadow mask 5 so that sufficient light reaches the photoresist film 4 behind the non-transparent bridge portion 8.

The length A of the linear light source 6 at this time greatly influences the shape of the opening formed on the light absorption layer.

In other words, if the length A of the linear light source 6 is optimally selected, the light from the linear light source 6 that passes through the opening 7 of the slot-shaped shadow mask 5 will reach the photoresist behind the non-transparent bridge portion 8. The light that has passed through the two apertures 7 adjacent to each other in the longitudinal direction of the apertures γ now reaches a suitable speed on the membrane 4.
The photoresist film behind the non-light-transmitting bridge portion 8 is overlaid under appropriate conditions and exposed to the same amount of light as the photo-resist film 4 behind the opening 7. It becomes possible to give on 4.

As a result, the influence of the non-transparent bridge portion 8 is eliminated, and the first
As shown in the figure, an aperture with good linearity and no unevenness can be provided on the light absorption layer.

In a color cathode ray tube having a black stripe type fluorescent surface prepared by such a method, during operation, the red, green, and blue colors are passed through the aperture 7 of the slot-type shadow mask 5. The electron beams from the three electron guns are passed through the three-color phosphor elements R, G, on the phosphor surface.
B is irradiated to excite the phosphor element and emit light.

However, as described above, this slot-type shadow mask 5 has the apertures 7 and the bridge portion 8 that shields the electron beam between the apertures 7, so that the phosphor surface where the phosphor element is excited and emitted light is has a non-light-emitting portion 9, as shown in FIG.

Here, in the figure, RN s GN + BN, red,
This is an excitation/emission section of three-color phosphor elements R2G and B that are excited and emit light by electron beams from green and blue electron guns, respectively.

Usually, a three-color phosphor element R filled with a light absorption layer 1 on both sides
, G, B, Wo, WB are made almost equally, and the excitation light emitting parts RN, GN of the three-color phosphor elements R, G, B are made almost equally.
t The length l in the longitudinal direction of BN is also the three-color phosphor element R, G
, B are equal, the light emitting areas of the excitation light emitting parts RN, GN, and BN are also equal.

Therefore, to obtain a constant white screen, the ratio of the beam currents of each color electron gun of red, green, and blue, and the white current ratio are the phosphors forming the three-color phosphor elements R, G, and B. In other words, if the chromaticity and brightness of the luminescent color of the phosphor are determined, then it is determined uniformly.

Therefore, in order to change the white current ratio, it is necessary to change the characteristics of the phosphor itself, but this is not easy to do.

Therefore, as a way to easily change the white current ratio, as shown in Figure 5, the widths WR2WG and WB of the three-color phosphor elements R, G, and B, whose sides are filled with light absorption layers, are intentionally made uneven. A method of adjusting has been proposed.

In the case of the fluorescent surface shown in FIG. 5, the width W of the fluorescent element G among the three-color fluorescent elements R, G, and H whose both sides are filled with the light absorption layer 1.

is formed to be thicker than the other two colors, so that the excitation/emission part RN + GN + of the three-color phosphor element R2G, B is excited and emitted by the electron beams from the red, green, and blue electron guns.
Of the BN, the light emitting area of the excitation light emitting section GN is larger than that of the excitation light emitting section ~ and BN.

Therefore, in this case, the beam current of the green electron gun can be reduced to obtain the same white current ratio compared to the case where the widths %, W, , wB are equal, and the beam current of the red, green, and blue electron guns can be reduced. It becomes possible to change the white current ratio.

The same applies to other colors, and according to this method, it is possible to change the white current ratio relatively easily.

However, in such a method, the widths WR9WG, W of the three-color phosphor elements R, G, B whose both sides are filled with light absorption layers are
B must always be maintained at a constant ratio, and it becomes necessary to always strictly control and manage the exposure amount corresponding to the three-color phosphor element of the exposure performed during the light absorption layer formation process. This method has the disadvantage that the manufacturing process for the fluorescent surface becomes complicated.

This invention was made in order to eliminate the drawbacks of the conventional ones, and it is an exposure method for the fluorescent surface of a color cathode ray tube that makes it possible to change the white current ratio without complicating the fluorescent surface manufacturing process. The present invention provides a method.

An embodiment of the present invention will be described below with reference to the drawings.

When the length A of the linear light source 6 is smaller than the optimum value in the conventional black stripe type fluorescent surface exposure method, the light reaching the rear of the non-transparent bridge portion 8 As a result, the overlapping exposure amounts become insufficient, and as shown in FIG. 7, openings having concave portions are formed at regular intervals on the light absorption layer.

Conversely, when the length A of the linear light ray 6 is thicker than the optimum value, more light reaches the rear of the non-transparent bridge portion 8, resulting in an excessive amount of superimposed exposure. As shown in the figure, openings having convex portions are formed on the light absorption layer at regular intervals.

In FIGS. 7 and 8, the uneven portions of the openings in the light absorption layer are different for each set of rows of three-color phosphor elements R, G, and B because of the slots shown in FIG. type shadow,
・The arrangement of the apertures 7 in the mask 5 is normally arranged in each row.
The reason for this is that the arrangement pitch in the longitudinal direction is shifted by -, but there is no difference.

The present invention was developed by considering the relationship between the exposure conditions and the characteristics of the formed fluorescent surface in relation to the exposure method used when forming the light absorption layer of such a black stripe type fluorescent surface. It is something.

Next, an embodiment of the exposure method according to the present invention will be described in detail with reference to FIG. 9 and FIG.

FIG. 9 shows a state in which a three-color phosphor element is excited to emit light by an electron beam on a phosphor surface having a light absorption layer formed by the exposure method according to the present invention, and is shown in a conventional method proposed for changing the white current ratio. This figure is drawn in the same way as in Figure 5, in which excited light emission was performed on the fluorescent surface.

In other words, this refers to the emission of light to the excited light-emitting parts of the three-color phosphor elements R, G, and B that are excited and emit light by the electron beams from the red, green, and blue electron guns. The area is made to be smaller than that of the excitation light emitting part RN + BN, and as a result, the same effect as in FIG. 5 can be obtained.

FIG. 10 is a schematic cross-sectional view for explaining a method of exposing a fluorescent surface according to an embodiment of the present invention.

In the exposure method according to the present invention, first of all, when exposing a photoresist film for forming a light absorption layer, an optimum linear shape is created to provide the light absorption layer with an aperture with good linearity and no irregularities unlike the conventional method. Rather than adapting the length of the light source, apertures with recesses or protrusions are intentionally formed on the light absorbing layer.

That is, as shown in FIG. 9, exposure is performed with a light source length shorter than the optimal length of the linear light source, in the same way as explained in FIG. 7.

Finally, in the exposure method according to the present invention, a linear light source 6 is used.
changing the facing position of the phosphor elements B and R during exposure,
The position g of the linear light source 6 when exposing the phosphor element G is exactly the same as in the conventional case, but the position g of the linear light source 6 when exposing the phosphor elements B and R is the same.

The distance r between the light source positions g and b and the distance between r and g is set to 28, which is exactly twice the conventional distance S.

When the photoresist film 4 is exposed in this state, the phosphor elements G are exposed in exactly the same way as before, and when the color cathode ray tube is operated, the phosphor elements of the three colors red, green, and blue are exposed. Exposure is performed by light that has passed through a longitudinal row of openings in a slot-type shadow mask through which the electron beam from the electron gun passes during excitation emission in a set of R, G, and B rows. However, the exposure of the phosphor elements Bs- and R is different from this, and as is clear from the figure, a row of apertures on the outside of a row of apertures in the longitudinal direction of the apertures 7 of the slot-type shadow mask 5 is used. Exposure is performed by light passing through the hole 7.

As described above, these outer rows of apertures 7 are shifted by one pitch from the row through which light passes during exposure of the phosphor element G. Therefore, as shown in FIG. 9, the phosphor surface is formed by exposure, and the position of the recessed part of the opening provided in the light absorption layer of the phosphor elements R button and B is different from that of the conventional phosphor surface. The portions 9 are formed with a deviation of - of the vertical alignment pinch.

On the phosphor surface formed in this manner, three phosphor elements 10 are arranged in three rows 1 from the outermost row in the arrangement direction of the three-color phosphor elements R, G, and B. This results in an irregular color arrangement, which causes a coloring phenomenon when a color cathode ray tube is operated, making it unsightly.

Therefore, it is desirable to perform an operation in which the opening on the light absorption layer or the phosphor element itself is removed during exposure of the phosphor surface.

For example, if we talk about the phosphor element G in the outermost phosphor element 10, when the phosphor element G is exposed, the linear light source 6
A shielding plate 1 is placed in the space between the slot-shaped shadow mask 50 and
1 is installed as shown in the figure, this light is blocked from the linear light source 6, and the opening on the light absorption layer of the phosphor element G in this area or the phosphor element itself is removed. .

Although the case of the phosphor element G has been described above, the phosphor elements B and R can also be omitted by similar means.

Red, green, and When irradiated with electron beams from the three blue electron guns, the slot-shaped shadow mask 5 except for the non-light-emitting portion 9 corresponding to the bridge portion 8 is excited to emit light as shown in the figure.

In the figure, RN, GN, and BN are the excitation light emitting parts of the three-color phosphor elements R, G, and H, as in the conventional case.

The width of the maximum part of this excitation light emitting part ~s GN y BN.

Although Wo and WB are approximately equal, the width of the phosphor element is narrow in the central portion of the excitation/emission portion RN + BN.

In such a configuration of the excitation light emitting section RN + GN, BN, the light emitting area of the excitation light emitting section GN is larger than that of the excitation light emitting section ~, BN, and a state substantially equivalent to that described with reference to FIG. 5 above is achieved. is obtained, making it possible to change the white current ratio.

In the past, the ratio of the light-emitting area was determined by keeping the exposure amount corresponding to the three-color phosphor elements R, G, and H constant during exposure when forming the light-absorbing layer, or by keeping the exposure amount constant for the excitation light-emitting portion.

If the widths W, , W, , WB of the maximum parts of GN and BN are kept constant, they are automatically determined by the length of the linear light source during exposure, so it is possible to element R,
It is not necessary to always use strict control buttons and manage the exposure amounts corresponding to G and B.

Moreover, the ratio of the light emitting area can be arbitrarily changed by appropriately selecting the length of the linear light source.

The above description has been about the case where a stationary linear light source is used as the exposure light source, but the present invention is not limited to this, and the invention is not limited to this. Similar effects can be obtained even when the exposure method is applied to an exposure method that is performed while reciprocating in the longitudinal direction of the aperture.

As described above, according to the method for exposing the phosphor surface of a color cathode ray tube according to the present invention, when the exposure button is pressed during the formation of the light absorbing layer, color phosphor elements are By performing exposure using light that has passed through a row of apertures that is different from the longitudinal row of apertures used for excited light emission during operation of a cathode ray tube, the exposure amount corresponding to the three-color phosphor element is always strictly controlled. The ratio of the light-emitting area of the three-color phosphor element can be changed without having to control the light-emitting area, and the ratio of the light-emitting area is always stable, making it easy to change the white current ratio of color and cathode ray tubes. This has the effect of making it possible to perform the process with high precision.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of a black stripe type fluorescent surface, and FIGS. 2 and 3 are both schematic cross-sectional views for explaining a conventional exposure method of a black stripe type fluorescent surface. FIG. 4 is a schematic plan view of a slot-type shadow mask, and FIG. 5 is a schematic plan view showing the state of excitation and emission of a three-color phosphor element with a black stripe type phosphor surface.
FIG. 6 is a schematic plan view of a fluorescent surface that is excited and emitted light for explaining the conventional method of changing the white current ratio, and FIGS.
The figures are schematic plan views of fluorescent surfaces formed by exposure when the length of the linear light source is smaller than the optimum value, and when the length is longer than the optimum value, respectively.
FIG. 9 is a schematic plan view showing the state of excitation and emission of a three-color phosphor element with a black stripe type fluorescent surface formed by an exposure method according to an embodiment of the present invention, and FIG. FIG. 2 is a schematic cross-sectional view for explaining a method of exposing a fluorescent surface according to an embodiment. DESCRIPTION OF SYMBOLS 1... Light absorption layer, 2... Black stripe type fluorescent surface, 4... Photoresist film, 5... Slot type shadow mask, 6... Linear light source, 7・・・
・Open hole. In the button diagrams, the same or corresponding parts are indicated by the same reference numerals.

Claims (1)

[Scope of Claims] 1. A color cathode ray tube having a phosphor surface formed by disposing a light absorption layer between strip-shaped three-color phosphor elements and a slot-shaped shadow mask. During operation, the red, green, and blue electron beams are excited and emit light by electron beams from the red, green, and blue electron guns that pass through the apertures arranged in one row in the longitudinal direction of the slot-shaped shadow mask. Among the rows of color phosphor elements, at least one row of color phosphor elements is different from one row in the longitudinal direction of the apertures used for excitation light emission during operation of a color cathode ray tube, depending on the exposure formation process of the phosphor surface. A method for exposing the fluorescent surface of a color cathode ray tube, which is characterized by exposing the fluorescent surface of a color cathode ray tube to light that has passed through a row of apertures. 2. By appropriately selecting the light source length of the linear light source used as the light source for exposing the fluorescent surface, the apertures of the light absorbing layer formed by exposure are made to have periodic convex portions or concave portions. A method for exposing a fluorescent surface of a color cathode ray tube according to claim 1. 3. For one to three rows of phosphor elements inward from the outermost row of three-color phosphor elements of red, green, and blue on the phosphor surface, the exposure light is shielded during exposure of the phosphor surface. A method for exposing a phosphor surface of a color cathode ray tube according to claim 1 or 2, characterized in that the aperture on the absorption layer or the phosphor element itself is omitted.