JPH10188803A - Chromatically correction method for color cathode-ray tube and color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct chromaticity at the time of forming a phosphor screen on a phosphor panel, and prevent the occurrence of improper chromaticity by correcting each chromaticity of green, blue and red via the adjustment of an amount of slurry containing carbon and sprayed to the back of a metal back after forming a phosphor stripe. SOLUTION: A color selection mechanism corresponding to a size is set on a panel after the formation of a phosphor stripe thereon but before the deposition of aluminum. Then, each chromaticity of green, blue and red is measured by an ultraviolet lamp. A preliminarily established carbon application amount is determined on the basis of the chromaticity measurement results, and a carbon feed amount is adjusted so as to obtain necessary transmittance. A panel face with metal back formed via the deposition of aluminum or the like is heated at the prescribed temperature, thereby preventing the carbonization of the phosphor stripe or an intermediate film, the deterioration of the bonding function of applied carbon and the occurrence of a spot. Thereafter, carbon is applied and then cooled at room temperature, thereby completing a color correcting process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting chromaticity of a color cathode ray tube and a color cathode ray tube. The present invention relates to a color cathode ray tube chromaticity correction method and a color cathode ray tube which can improve quality.

[0002]

2. Description of the Related Art One of quality requirements for a color cathode ray tube is chromaticity. The chromaticity quality is related to whether or not the green, blue, and red single colors are each colored so as to be within a predetermined allowable range. Conventional measures for improving and adjusting the chromaticity can be broadly divided into two: an improvement on the phosphor material and an improvement on the phosphor screen manufacturing process.
As the former improvement measures regarding the phosphor material, addition of a pigment, and adjustment of the addition amount, and further, adjustment of the chromaticity point of the powder phosphor by adjustment of an activator contributing to light emission and the like are performed. I have. Further, the mixing ratio of the phosphor and the binder in a slurry (suspension) obtained by adding a binder and various additives to these phosphors is also adjusted. As an improvement measure for the latter phosphor screen forming process, the mutual balance of application, drying, exposure and development of a slurry containing a phosphor is adjusted in order to reduce color mixture of other colors.

[0003]

The measures for improving and adjusting the chromaticity described in the prior art are all redeveloped,
It is a kind of redesign, and it takes a long time, such as a week or a month, to obtain the results of improvement or adjustment. Moreover, for chromaticity defects caused by various variations,
Not valid. In addition, there is a problem that the improvement method based on the manufacturing conditions lacks responsiveness, such as inviting an increase in other defects. Further, the most fatal problem is that there is no countermeasure for the completed phosphor panel other than treating it as a defective product. As described above, various countermeasures that have been conventionally performed with respect to improvement and adjustment of chromaticity are all types of so-called redevelopment, and there is no help in adjusting the chromaticity of the completed phosphor screen. .

SUMMARY OF THE INVENTION It is an object of the present invention to prevent chromaticity defects from occurring, by making it possible to adjust chromaticity when producing a phosphor screen of a phosphor panel of a color cathode ray tube. Another object is to shorten a period for improving chromaticity.

[0005]

According to the chromaticity correction method for a color cathode ray tube of the present invention, a phosphor panel of a color cathode ray tube in which a phosphor stripe is formed and a metal back of an aluminum vapor-deposited film or the like is formed on the back thereof. In the phosphor screen manufacturing process of
A step of spraying a slurry containing carbon on the back surface of the metal back to form a carbon film is added, and the chromaticity of blue, green, and red is corrected by adjusting the spray amount of the slurry.

In the chromaticity correction method for a color cathode ray tube according to the second aspect, the spray amount of the slurry is controlled so as to be large when the chromaticity is shallow with respect to the reference value, and to be small or zero when the chromaticity is deep with respect to the reference value. doing.

According to a third aspect of the present invention, the spray amount of the slurry is set in advance to correct the chromaticity of one or two of blue, green, and red. , The process of forming a carbon film, blue, green,
It is added only when the chromaticity of one or two of the red colors deviates from a preset allowable range.

In the color cathode ray tube according to the present invention, a carbon thin film for correcting chromaticity of blue, green and red is formed on the back surface of the metal back.

In a color cathode ray tube according to a fifth aspect of the present invention, the carbon thin film has a thickness set in advance to correct the chromaticity of one or two of the three colors of blue, green and red.

According to a sixth aspect of the present invention, there is provided a color cathode ray tube chromaticity correcting method, wherein a fluorescent dot of a shadow mask type is formed, and a metal back such as an aluminum vapor-deposited film is formed on the back surface of the fluorescent dot. In the surface manufacturing process,
A step of spraying a slurry containing carbon on the back surface of the metal back to form a carbon film is added, and the chromaticity of blue, green, and red is corrected by adjusting the spray amount of the slurry.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a chromaticity correction method for a color cathode ray tube and a color cathode ray tube according to the present invention will be described with reference to the drawings. In the present invention, there are various factors such as color mixing, electron beam hitting, and the like, which cause deterioration of color purity in a color cathode ray tube. Focusing on the fact that it is possible to suppress chromaticity and improve the chromaticity, the chromaticity of the phosphor parne is measured at the stage when the phosphor screen is completed in the phosphor screen manufacturing process, and the metal back After vapor deposition, carbon is applied to the back surface, and the characteristic feature is that the amount of carbon applied at that time is determined based on the result of the chromaticity measurement.

As described in connection with the prior art, the chromaticity quality is such that green, blue and red single colors are developed.
This is related to whether or not the color is developed so as to be within a predetermined allowable range. In most cases, the cause of the defect generated in the phosphor screen manufacturing process is that only one of the three colors is out of the allowable range.
Therefore, if the color purity of a single color outside the allowable range can be improved, the phosphor panel becomes a product judged to have good chromaticity quality. According to the present invention, a carbon thin film is applied to the back surface of the metal back of all the color phosphor panels, and is converted into weak electrons (secondary electrons or scattered electrons) by the carbon thin film, thereby emitting light of another color. A first method for suppressing green, blue,
When one or two of the three single colors of red deviate from a predetermined allowable range, a carbon thin film is formed on the back surface of the metal back to correct (adjust) the chromaticity of the color outside the allowable range. And a second method of applying

First Embodiment The first embodiment relates to the first and second aspects of the present invention.
The present invention corresponds to the fourth and fifth aspects of the present invention, but also relates to the third aspect of the present invention. The first embodiment is the first method, in which a carbon thin film is applied to the back surface of the metal back of all of the color phosphor panels. By adjusting the thickness of the carbon thin film, 2
The color purity is improved by changing the capture state of secondary electrons and scattered electrons, and the yield is improved. The inventor of this application has experimentally confirmed that, when a carbon thin film is applied to the back surface of a metal back, there is a correlation between the thickness of the carbon thin film and the color depth (hue). Next, the transition of the carbon coating amount and the chromaticity of a single color will be described.

FIG. 2 is a characteristic diagram showing an example of a carbon coating amount and a chromaticity transition by CIE for green. In the figure, G indicates a green characteristic curve, circles indicate measured values, MBC indicates no carbon coating, and MBC 30% indicates a transmittance of 30%.

FIG. 2 shows a state in which green chromaticity changes in relation to the thickness (coating amount) of the carbon thin film when a carbon thin film is formed on the back surface of the metal back of the color phosphor panel. Is shown. The green characteristic in FIG. 2 plots the experimental result of the relationship between the thickness (coating amount) of the carbon thin film and the change in chromaticity, and is a case where the thickness of the carbon thin film is controlled by transmittance. . The transmittance is defined as 100% in a state where carbon is not applied (transmittance of only glass before application). No MBC shown in FIG. 2 (594 on the vertical axis)
Are plotted when carbon is not applied, and the chromaticity of green at a transmittance of 100%.
The two points above MBC 30% (plotted at 597 on the vertical axis) are green chromaticity in a state where 70% of light is absorbed by the applied carbon thin film and transmittance is 30%. . Between these, the chromaticity was measured at 53% (plotted at 596 on the vertical axis) and at 77% (plotted at 595 on the vertical axis) in terms of transmittance. Therefore, by connecting these average points, a green characteristic curve G is obtained. The green characteristic curve G is a so-called left-up characteristic, and the change amount in the vertical axis direction is larger than the change in the horizontal axis direction. It is also possible.

In the case of green, the chromaticity becomes deeper in the upper part of the vertical axis (from 594 in the vertical axis toward 597), so that the transmittance is lowered (the amount of carbon applied to the back surface of the metal back is increased). ) Increases the chromaticity, and conversely, increasing the transmittance (decreasing the amount of carbon) decreases the chromaticity. In the first embodiment, in green in FIG.
For example, a transmittance of 50% (slightly above 596 on the vertical axis) or 6
0% (slightly below 595 on the vertical axis) is set as a reference transmittance. If the measurement result of the chromaticity of green deviates from the chromaticity corresponding to the reference transmittance, for example, if the chromaticity is shallow (the value on the vertical axis is small), the carbon coating is performed. When the amount is large (dark), the transmittance is reduced. When the chromaticity is deep (the value on the vertical axis is large), the transmittance is increased by decreasing (thin) the carbon coating amount. Thus, a desired chromaticity can be obtained by adjusting the coating amount of carbon based on the measurement result of the chromaticity. The above is the case of green, but the same applies to other blues and reds in that the amount of carbon applied is adjusted based on the chromaticity measurement results.

FIG. 3 is a characteristic diagram showing an example of a change in chromaticity due to carbon coating amount and CIE for blue. The reference numerals in the figure are the same as those in FIG. 2, and B indicates a blue characteristic curve.

Also in the case of the blue color shown in FIG. 3, the chromaticity of the blue color changes by changing the amount of carbon applied. However, in the case of FIG. 3, one point of no MBC (plotted at 70 on the vertical axis) is a case where carbon was not applied, and each point of MBC 30% (plotted at 67 and 66 on the vertical axis). One point is 70% due to the applied carbon thin film.
% Chromaticity is a state in which 30% of light is absorbed and 30% of light is transmitted. Then, also in the case of this blue color, connecting these average points results in a so-called left-downward characteristic curve B,
The smaller the value on the vertical axis, the deeper the blue color. Therefore,
As described above, if the reference transmittance is set to 50% or 60%, if the measurement result of the chromaticity of blue deviates from the chromaticity corresponding to the reference transmittance, for example, When the chromaticity is shallow (when the value on the vertical axis is large), the transmittance is reduced by increasing (darkening) the carbon coating amount, and conversely, when the chromaticity is deep (when the value on the vertical axis is small), If the transmittance is increased by reducing (thinning) the carbon coating amount, a predetermined chromaticity can be obtained as in the case of the green color.

FIG. 4 is a characteristic diagram showing an example of the carbon coating amount and the chromaticity transition by CIE for red. The reference numerals in the drawing are the same as those in FIG. 2, and R indicates a red characteristic curve.

In the case of the red color shown in FIG.
Unlike the green color shown in FIG. 3 and the blue color shown in FIG. 3, when the amount of carbon applied is increased, the chromaticity changes in the horizontal direction. In the case of this red color, the characteristic curve R is almost flat, but slightly lower right, and the change amount in the horizontal axis direction is larger than the change amount in the vertical axis direction. However, the correlation between the thickness of the carbon thin film and the color depth (hue) is basically the same as that of green or blue. That is, without MBC (626 or 627 on the horizontal axis)
The three points are the cases where carbon is not applied, and the transmittance is 1
The chromaticity of red in the state of 00%. Rightmost MBC3
Each one of 0% (plotted at 634 and 635 on the horizontal axis)
The point is the red chromaticity in a state where 70% of the light is absorbed by the applied carbon thin film and the transmittance is 30%. By connecting these average points, a red characteristic curve R is obtained. Also in this case, as described above, if the reference transmittance is set to 50% or 60%, the measurement result of the red chromaticity is shifted from the chromaticity corresponding to the reference transmittance. For example, when the chromaticity is shallow (when the value on the horizontal axis is small), the transmittance is reduced by increasing (darkening) the carbon coating amount, and conversely, when the chromaticity is deep (when the value on the horizontal axis is small). If it is large, if the amount of carbon applied is reduced (thinned) and the transmittance is increased, a predetermined chromaticity can be obtained as in the case of green or blue.

As described above, when the carbon thin film is applied to the back surface of the metal back for the constituent primary colors green, blue and red in the color cathode ray tube, the thickness of the carbon thin film is correlated with the color depth (hue). Has been confirmed. Experiments have also confirmed that a desired chromaticity can be obtained by changing the coating amount of carbon. In the first embodiment, after a phosphor is applied to a panel glass in a phosphor screen manufacturing process, the respective chromaticities of green, blue and red, which are the constituent primary colors in a color cathode ray tube, are measured and set in advance. For a phosphor panel having a color outside the allowable chromaticity range, after performing metal back vapor deposition, an amount of carbon is applied to the back surface so that the chromaticity of the color outside the allowable range falls within a predetermined range. If all the chromaticities of the three colors green, blue and red are within the allowable range, the reference transmittance is 50 or 6
The carbon corresponding to the transmittance of 0% is applied.

On the other hand, when the chromaticity of a certain color is out of the allowable range, the amount of carbon coating corresponding to the transmittance at which the chromaticity of the color falls within the predetermined range is determined. That is, as described above, when the chromaticity of the color is deep, the coating amount of carbon is reduced (thin coating film) or set to zero, and conversely, when the chromaticity of the color is shallow, Increase the coating amount (thicken the coating film). The change in the transmittance also changes the chromaticity of other colors that are already within the allowable range, but the reference transmittance is 50 or 60%.
On the other hand, since the chromaticity within the allowable range can be sufficiently obtained even if the transmittance slightly changes, it is possible to correct the chromaticity of the phosphor panel which has been conventionally determined to have poor chromaticity. In this case, the allowable chromaticity range of each color of green, blue, and red is different depending on the shape and size of the color cathode ray tube and whether the required quality is high quality or normal quality. Is set in advance by experiment or the like for each format as in the prior art. Next, a method of correcting chromaticity according to the present invention will be described.

FIG. 1 is a process chart showing an example of an embodiment of a monochromatic chromaticity correction step in the chromaticity correction method for a color cathode ray tube according to the present invention. In the figure, P1 to P
5 shows a process.

In a first step P1, a phosphor stripe is formed in a phosphor screen step, and a panel before aluminum deposition is formed on the panel.
Color sorting mechanism corresponding to the size (aperture grill)
And set green, blue,
Measure each chromaticity of red. In the second step P2, the amount of carbon to be applied is determined in advance based on experimental results based on the chromaticity measurement results of the respective colors. In a third step P3, the amount of carbon applied is adjusted. In adjusting the amount of carbon coating, the amount of carbon may be controlled based on the transmittance as described above. In the management based on the transmittance, the transmittance of only the glass before coating is set to 100%, and the supply amount of carbon is controlled so that the required transmittance is obtained.

In a fourth step P4, the phosphor panel is heated. This step of heating the phosphor panel is a step performed to enhance the adhesiveness of the carbon to be applied, and heats the panel face surface on which the metal back is formed by aluminum evaporation or the like to 70 ° C. ± 3 ° C. The reason for setting such a temperature range is that if the temperature exceeds 78 ° C., the phosphor stripes and intermediate films formed on the face surface of the panel may be carbonized. This is because it may cause deterioration of the adhesiveness and generation of stains. Finally, in a fifth step P5, carbon is applied, and then cooled at room temperature around 25 ° C. The above first
Through the fifth steps P1 to P5, a phosphor panel for a color cathode-ray tube whose chromaticity has been corrected is obtained. Thereafter, the process returns to the normal cathode ray tube manufacturing process. Finally,
An apparatus used in each step will be briefly described.

FIGS. 5A and 5B show the main components of an apparatus used in the carbon coating step in the chromaticity correction method of the present invention. FIG. 5A shows chromaticity measuring means, and FIG. It is a figure showing a means. In the reference numerals in the drawing, 1 is a chromaticity exposure table, 2 is a color analyzer, 3 is a phosphor panel, 4
Denotes a coating amount measuring unit, 4a denotes a light source, 4b denotes a light receiving unit, 5 denotes a coating sample glass, and 6 denotes a transmittance detector.

FIG. 6 is a diagram showing a main configuration of panel heating / carbon coating means used in the carbon coating step in the chromaticity correction method of the present invention. The reference numerals in the figure are the same as those in FIG. 5, 3 'is a phosphor panel, 7 is a carbon coating device, 7a is a carbon feed tank, 7b is a carbon coating unit, 7c is an electric heating furnace, 7d and 7e are temperature sensors,
7f indicates a temperature control unit.

In the carbon coating step shown in FIG. 1, a chromaticity measuring means as shown in FIG. 5A is used in the first step P1. The chromaticity measuring means and measuring method are conventionally known, and are basically the same as, for example, the measurement (inspection) of each chromaticity performed after forming a carbon stripe and a phosphor stripe. That is, in the process of manufacturing a phosphor panel for a color cathode ray tube, a carbon stripe and green, blue, and red phosphor stripes are sequentially formed on a glass panel. After that, a metal back such as an amyl vapor-deposited film is formed on the back surface. For quality control, each chromaticity of green, blue and red is measured before the step of forming the metal back. In the chromaticity measuring means shown in FIG. 5 (1), a phosphor panel 3 having a completed phosphor screen is set on a chromaticity exposure table 1, and each color of green, blue and red is irradiated by a color analyzer 2 while irradiating ultraviolet rays. The chromaticity is measured each time.

In this case, the conventional chromaticity measurement only determines whether or not the chromaticity of each color set in advance is within an allowable range (inspection standard). According to the chromaticity correction method of the present invention, not only the same judgment as in the past, but also the measurement results
When the chromaticity of only one of the blue and red colors, for example, is out of the set allowable range, a numerical measurement is performed on the degree of the deviation. The reason for this is that conventionally, an inspection for performing a metal back process in the next step is performed, and manufacturing costs are reduced by shifting only acceptable products to the next step. On the other hand, in the present invention, as described above, it is necessary to determine the carbon coating amount for performing the chromaticity correction in the second step P2.
Then, the chromaticity of each color is measured, the pass / fail judgment is made, and when the color is rejected, an accurate value of the chromaticity is obtained.

In the second step P2, as a result of the chromaticity measurement, if one or two colors are out of the allowable range, the carbon to be applied in the fifth step P5 is determined based on the measurement result. Determine the amount. The carbon coating amount in this case has already been described in detail with reference to FIGS. FIG. 5 (2) shows a carbon coating amount measuring means. The coating sample glass 5 is set in the coating amount measuring section 4 and the light source 4a
Is turned on to irradiate light. The transmitted light is detected by the light receiving section 4b, and the transmittance detector 6 detects the transmitted light in%. In this case, the transmittance is set to 100%, and the carbon coating amount is determined in a range such as 100% to 30%.

FIG. 6 is a schematic side view of a carbon coating apparatus 7 showing one example of the coating panel heating / carbon coating means used in the fourth and fifth steps P4 and P5. The carbon coating device 7 detects the temperature of the set phosphor panel 3 by a temperature sensor 7d, and a temperature control unit 7f
Inform The temperature control unit 7f determines the time and heating temperature required to heat the phosphor panel 3 to 70 ° C. ± 3 ° C. in the electric heating furnace 7c, and heats the loaded phosphor panel 3 (second temperature). Step P4 of Step 4). The phosphor panel 3 heated to the predetermined temperature is thereafter moved to a position corresponding to the carbon coating section 7b, and carbon is supplied from the carbon pressurizing tank 7a to apply carbon to the phosphor panel 3 '. And it cools at room temperature of about 25 degreeC measured by the temperature sensor 7e (5th process P5).

As described above, in the chromaticity correction method for a color cathode ray tube according to the present invention, the phosphor stripe of the color cathode ray tube is formed by forming a metal back such as an aluminum vapor-deposited film on the back surface. In the surface manufacturing process, a step of forming a carbon film by spraying a slurry containing carbon on the back surface of the metal back is added, and the chromaticity of blue, green, and red is corrected by adjusting the spray amount of the slurry. (The invention of claim 1). Further, the spray amount of the slurry is controlled so as to be large when the chromaticity is shallow with respect to the reference value, and to be small or zero when the chromaticity is deep with respect to the reference value (the invention of claim 2). Further, a carbon film is formed on the back surface of the metal back in the color cathode ray tube which has been subjected to the chromaticity correction method (the invention according to claims 4 and 5). Therefore, the chromaticity correction after the completion of the phosphor screen of the panel glass becomes possible, the period for improving the chromaticity is shortened, and the chromaticity defect is prevented beforehand.
The quality for the subsequent process following the phosphor screen manufacturing process can be guaranteed. In addition, since the number of phosphor panels of a color cathode ray tube which has conventionally been discarded due to poor chromaticity can be significantly reduced, the yield is improved and the cost is reduced.

Second Embodiment This second embodiment corresponds to the third aspect of the present invention. As a result of chromaticity measurement, one or two colors out of an allowable range are detected. This is a second method of applying a carbon thin film on the back surface of the metal back to correct (adjust). In the first embodiment, the first method of applying a carbon thin film to the back surface of the metal back of all the color phosphor panels has been described. For example, a color cathode ray tube for which the chromaticity quality requirement is not so strict is described. In such a case, if a carbon thin film is applied to the back of the metal back of the phosphor panel, the cost will increase accordingly.

In the second embodiment, the state in which the carbon thin film is not coated on the back surface of the metal back is green, blue,
When the chromaticity of one of the three colors, for example, the chromaticity of green is out of the allowable range, as a result of the chromaticity measurement, the chromaticity of green becomes the allowable range. Apply carbon with transmittance. In this case,
The other two colors in which the chromaticity of the allowable range is obtained, that is, blue and red also change the chromaticity due to the application of the carbon, but if the chromaticity after the change of the two colors is all within the allowable range, The chromaticity quality is determined to be acceptable by applying the carbon. The basic principle is the same as in the first embodiment. Therefore, according to the second embodiment, when the chromaticity of only one color deviates from the allowable range, the degree of deviation of the chromaticity determines the carbon coating amount (managed by the transmittance). Thus, the range that can be corrected can be easily adjusted.

Third Embodiment This third embodiment corresponds to the sixth aspect of the present invention. In the first and second embodiments, the case where the chromaticity of the phosphor panel having the phosphor stripe is corrected (adjusted) has been described. The third embodiment relates to a shadow mask type phosphor panel of a color cathode ray tube.
Similarly, this is a case where the chromaticity is corrected (adjusted). The basic principle is the same as that of the phosphor panel having the phosphor stripes described above. When the phosphor dots are formed, the monochromatic chromaticity of each of green, blue, and red is measured. After forming a metal back such as an aluminum evaporation film based on the measurement result,
Apply a carbon thin film.

Also in the third embodiment, as described in the first embodiment, the amount of carbon applied is controlled by the transmittance, and the reference transmittance is set to 50% or 60%. hand,
When the chromaticity of the three colors of green, blue, and red are all within the allowable range as in the first method of changing the transmittance and the second embodiment, the carbon thin film is formed after forming the metal back. A second method of applying a required amount of carbon only when the chromaticity can be corrected by applying carbon when one of the three colors is out of an allowable range as a result of the chromaticity measurement without addition. And can be adopted. To put it simply, with respect to the doming that occurs in the shadow mask, other colors (color mixing) occur due to heating of the color selection mechanism (aperture grill) (so-called temperature drift), but the amount of temperature drift in this case is reduced. be able to. Also in this case, since energy due to secondary electrons, scattered electrons, and the like is converted into a current by the carbon coating film, the color purity is improved and the yield is improved.

[0037]

According to the chromaticity correction method for a color cathode ray tube according to the first aspect of the present invention, a phosphor screen is formed on a phosphor panel of a color cathode ray tube in which a phosphor stripe is formed and a metal back such as an aluminum vapor-deposited film is formed on the back thereof. In the process, a step of forming a carbon film by spraying a slurry containing carbon on the back surface of the metal back is added, and the chromaticity of blue, green, and red is corrected by adjusting the spray amount of the slurry. Therefore, the chromaticity can be corrected after the phosphor screen of the panel glass is completed, the time required for chromaticity improvement can be shortened, chromaticity defects can be prevented, and the quality of the subsequent process following the phosphor screen manufacturing process can be guaranteed. can do. Further, since the number of phosphor panels of a color cathode ray tube which has conventionally been discarded due to poor chromaticity can be significantly reduced, the yield is improved and the cost is reduced.

In the chromaticity correction method for a color cathode ray tube according to a second aspect, in the chromaticity correction method according to the first aspect, the spray amount of the slurry is large when the chromaticity is shallow with respect to the reference value, and the chromaticity is deep. Sometimes it is small or zero. Therefore, in addition to the effect of the color cathode ray tube chromaticity correction method of the first aspect, the chromaticity correction range can be widened.

According to a third aspect of the present invention, in the method of correcting a chromaticity of a color cathode ray tube, the spray amount of the slurry is determined by adjusting the chromaticity of one or two of blue, green and red. It is set in advance for correction, and a step of forming a carbon film is added only when the chromaticity of one or two of blue, green, and red is out of a predetermined allowable range. I have. Therefore, in addition to the effect of the chromaticity correction method of the color cathode ray tube according to the first aspect, when the step of forming the carbon film can be omitted, the cost can be reduced by reducing the number of steps.

In the color cathode ray tube of the present invention, a carbon thin film for correcting chromaticity of blue, green and red is formed on the back of the metal back. Therefore, claim 1
The same effect as the chromaticity correction method of the color cathode ray tube described above can be obtained.

In the color cathode ray tube according to the fifth aspect,
In the color cathode ray tube described above, the carbon thin film has a thickness set in advance to correct the chromaticity of one or two of the three colors of blue, green and red. Therefore,
In addition to the effect of the color cathode ray tube of the fourth aspect, the same effect as the chromaticity correction method of the third aspect can be obtained.

In the chromaticity correction method for a color cathode ray tube according to a sixth aspect of the present invention, a phosphor dot of a color cathode ray tube is formed by forming a shadow mask type phosphor dot and forming a metal back such as an aluminum deposition film on the back surface. In the surface manufacturing process,
The same processing as in the color cathode ray tube chromaticity correction method of claim 1 is performed. Therefore, the same effect as the chromaticity correction method of the first aspect can be obtained for the shadow mask type color cathode ray tube.

[Brief description of the drawings]

FIG. 1 is a process diagram showing an example of an embodiment of a monochromatic chromaticity correction step in a chromaticity correction method for a color cathode ray tube according to the present invention.

FIG. 2 is a characteristic diagram illustrating an example of a change in chromaticity due to carbon coating amount and CIE for green.

FIG. 3 is a characteristic diagram showing an example of a change in chromaticity due to carbon application amount and CIE for blue.

FIG. 4 is a characteristic diagram showing an example of a carbon coating amount and a chromaticity transition by CIE for red.

FIG. 5 is a diagram showing a main configuration of an apparatus used in a carbon coating step in the chromaticity correction method of the present invention.

FIG. 6 is a diagram showing a main configuration of a panel heating / carbon coating unit used in a carbon coating step in the chromaticity correction method of the present invention.

[Explanation of symbols]

1 chromaticity exposure table, 2 color analyzer, 3 and 3 '
Phosphor panel, 4 coating amount measuring section, 4a light source, 4b
Light receiving unit, 5 sample glass for coating, 6 transmittance detector, 7
Carbon coating device, 7a Carbon pumping tank, 7b
Carbon coating unit, 7c electric heating furnace, 7d and 7e temperature sensors, 7f temperature control unit

Claims (6)

[Claims] In a process of manufacturing a phosphor screen of a color cathode ray tube phosphor panel in which a phosphor stripe is formed and a metal back such as an aluminum deposition film is formed on the back thereof, a slurry containing carbon is formed on the back of the metal back. By adding a process to form a carbon film by spraying and adjusting the spray amount of the slurry, blue, green,
A chromaticity correction method characterized by correcting each chromaticity of red. 2. The chromaticity correction according to claim 1, wherein the spray amount of the slurry is large when the chromaticity is shallow with respect to a reference value, and is small or zero when the chromaticity is deep. Method. 3. The spray amount of the slurry is set in advance to correct the chromaticity of one or two colors of blue, green, and red, and the step of forming the carbon film includes the steps of: 2. The chromaticity correcting method according to claim 1, wherein the chromaticity is added only when the chromaticity of one or two of green and red is out of a preset allowable range. 4. A color cathode-ray tube having a phosphor panel on which a phosphor stripe is formed and a metal back of an aluminum vapor-deposited film or the like formed on the back thereof, wherein blue, green, and red chromaticities are formed on the back of the metal back. A color cathode ray tube characterized in that a carbon thin film is formed for compensating for color distortion. 5. The method according to claim 1, wherein the carbon thin film has a thickness set in advance to correct the chromaticity of one or two of the three colors of blue, green and red. The color cathode ray tube according to claim 4. 6. A process for producing a phosphor screen of a color cathode ray tube, in which phosphor dots of a shadow mask type are formed and a metal back of an aluminum vapor-deposited film or the like is formed on the back thereof, By adding a step of forming a carbon film by spraying a slurry containing
A chromaticity correction method comprising correcting red chromaticity.