JPH03122945A - Fluorescent substance missing amount measuring method due to mislanding - Google Patents

Abstract

PURPOSE:To provide practicability of measuring the missing amount of fluorescent substance easily and accurately by calculating the light emission area of the fluorescent substance in the mislanding condition of the basis of the ratio of light quantity measured in the mislanding condition to the max. light quantity, subjecting the result from calculation to specified computing processes, and determining the missing amount of fluorescent substance. CONSTITUTION:After the light quantity from a fluorescent substance 8 at the time of mislanding is measured at the tube surface light quantity measuring stage, electron beam 10 is moved forcedly at the landing position shift stage to have just landing, and at the missing amount calculating stage, the missing amount (e) is calculated from the light quantity at the time and the light quantity at the time of mislanding. That is, the light quantity at mislanding and the light quantity at forced just landing are measured using a photo-sensor 11, and the missing amount is calculated from the fact that the area of light emission region determined as the ratio between the two is a function depending upon the missing amount. High precision measurement is thus made using a device of simple constitution.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a shadow mask type color cathode ray tube (hereinafter referred to as
Mislande ink is used to measure the size of the non-emission area of the phosphor when mislande ink of the electron beam occurs on the phosphor on the tube surface, that is, the amount of missing phosphor in CRTs. The present invention relates to a method for measuring the amount of chipping of a phosphor.

[Conventional technology]

In general, in CRTs used in televisions, monitors, etc., the landing of the electron beam is not uniform over the entire surface of the phosphor screen due to non-uniformity in the manufacturing of the tube body, non-uniformity in the electron gun or deflection yoke, etc. This is often not done, and electron beam mislanding is likely to occur, especially at the corners of the tube surface.

As one of the measurement items regarding this Misland ink,
It is necessary to measure the amount of missing phosphor.

FIG. 8 (al, (bl) is a block diagram showing a method for measuring the amount of missing phosphor using a conventional Misland ink. In the figure, 1 is a CRT, 2 is a deflection yoke provided at the neck of the CRT, and 3 1 is a CRT microscope for magnifying and visualizing the tube surface of the CRTl; 4 is a CCD camera; 5 is a lens system attached to the CCD camera 4; 6 is an image measuring device to which the CCD camera 4 is connected.

Next, the operation will be explained.

The first measurement method (FIG. 8(a)) uses a CRT microscope 3.
A part of the tube surface of the CRTl is enlarged, and the size of the non-emission region of the phosphor due to the misalignment between the phosphor and the electron beam is visually read using the scale inside the microscope or the diameter of the phosphor as a guide.

In the second measurement method (FIG. 8(b)), a part of the tube surface is imaged by a CCD camera 4 through a lens system 5. FIG. 9 shows an input image from the CCD camera 4, and the camera field of view 7
There is a phosphor 8 and a surrounding black matrix part 9 inside the phosphor 8, and the phosphor 8 is irradiated with an electron beam 10 with the centers of the two deviated from each other. A region 8b is generated. Here, the non-emission area 8
Let the maximum width of b be the missing amount e of the phosphor 8.

Since there is a clear difference in shading between the light-emitting region 8a, the non-light-emitting region 8b, and the black matrix portion 9, the edges of the three parts are detected by the image measuring device 6 using this difference in shading. By performing image processing such as value conversion, the shape of the non-emission region 8b is obtained, and by detecting its maximum width, the above-mentioned missing amount e can be obtained.

In addition, as a prior art related to this invention, there is one disclosed in, for example, Japanese Patent Laid-Open No. 62-20222.

[Problem to be solved by the invention]

Since the conventional method for measuring the amount of chipped phosphor using Mislande ink is configured as shown in 5 above, in the case of the second measurement method, in order to obtain sufficient accuracy, even if the diameter of the phosphor 8 is the smallest, Approximately 1/10 of the camera field of view 7 is required, and in that case, the camera field of view 7 needs to be expanded to a level of several mm or less, and if it is expanded to that level, the lens system 5 will cause insufficient light intensity and the measurement system will vibrate due to the expansion. Problems such as these occur, making measurement difficult, requiring expensive lenses and measures to prevent vibrations. For this reason, the first method is generally used, but the first measurement method is a visual measurement, so
There are large measurement variations due to people and instruments such as microscopes.
In addition, there were other problems such as the measurement time being long.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for measuring the amount of phosphor chipping using a misland ink, which allows the amount of phosphor chipping to be easily and accurately measured.

[Means to solve the problem]

In the method for measuring the amount of missing phosphor using misland ink according to the present invention, after measuring the amount of light of the phosphor during misland inking in the tube surface light intensity measuring step, the electron beam is moved intensely in the landing position moving step. Then, in the chipping amount calculation step, the chipping amount e is calculated from the light amount at that time and the light amount at the time of mislanding.

[For production]

In the chipping amount calculation step of the chipping amount measuring method of the phosphor due to mislanding ink according to the present invention, an optical sensor is used to measure the amount of light during mislanding and the amount of light when forced to just land, Since the area of the light emitting region determined by the ratio of the two is a function of the amount of chipping, the amount of chipping can be calculated.

[Embodiments of the invention]

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

In FIG. 1, 1 is a CRT, 2 is a deflection yoke provided on the CRTl, 11 is an optical sensor section for detecting the amount of light on the tube surface using, for example, a COD element, and 12 is a sensor measurement unit to be described later.
This is a measuring device that performs wobbling control and processing of measurement results.

FIG. 2 is a front view showing the optical sensor section 11, and a pair of vertical wobbling coils 13 and a pair of horizontal wobbling coils 1 are provided at four locations around the sensor 11a of the optical sensor section 11, respectively.
4 is installed.

Next, the operation will be explained.

Now, assume that the landing state of the electron beam 1o on, for example, the red phosphor 8 at an arbitrary point on the tube surface is the state shown in FIG. 3(4). When the light sensor unit 11 detects the light amount at this point, as shown in FIG. (tube surface light amount measurement process). Note that G and B indicate green and blue phosphors 8 that do not emit light.

Next, by passing a current -11 through the horizontal wobbling coil 14, the electron beam 10 is forcibly moved in the horizontal direction, and the amount of light KB at this time is measured. Next, the electron beam 10 is forcibly moved in the horizontal direction opposite to the above direction by flowing the current element 1 through the horizontal wobbling coil 14, and the amount of light Kc at this time is measured. Above KA, K
Suppose that the light amount change characteristic curve shown in FIG. 5 is obtained from B and KcK.

In the case of this characteristic curve, since Kn is the maximum light amount, it is assumed that a just landing state in the horizontal direction is obtained at this time. In the vertical direction, by flowing currents in opposite directions to the vertical wobbling coil 13 in the same manner as described above, the electron beam 10 is forcibly moved in the vertical direction, and the maximum light intensity in the vertical just-landing state is Detect KB. When the just landing state in the horizontal and vertical directions is obtained as described above, the center of the phosphor 8 and the electron beam 10 are
is in a just-landing state in which the center of the plane coincides with the center of the plane (landing position movement process).

Note that in the same figure (cl is the landing state when the light quantity Kc is obtained by the above-mentioned current element 11).

Next, a description will be given of a chipping amount calculation step for calculating the chipping amount e of the phosphor 8 using the light amount KA in the mislanded ink state and the light amount KB in the just landing state.

In FIG. 6, the radius r of the phosphor 80, the electron beam 10
The zero radius is rl, the distance between the center of the phosphor 8 and the center of the electron beam 10 is d, and the light emitting area of the light emitting region 8a is S. Now, assuming that the phosphor B and the electron beam 10 are perfectly circular, and considering the ideal state of light emitting area x detected light amount KA, then the following holds true. At this time, the light emitting area S becomes a function of the amount of chipping e, and is expressed as S = f (el).The characteristic curve a shown in FIG.
) shows the relationship between S and e in the equation.

Therefore, the light amounts KA and KB are detected, and the above formula (11, f
By using . . . 21, the missing amount e can be calculated. In reality, there are variations in the shape and radius of the phosphor 8 and the electron beam 10, and the relationship between the light emitting area Soc and the light amount KA is also affected by the density of the electron beam 10, etc., and cannot be said to be perfect. Therefore, the characteristics shown in FIG. As shown by curve b, the characteristic curve a deviates from the ideal state characteristic curve a.

However, if the amount of correction from characteristic curve a to b is measured in advance and the correction coefficient of equation (1), (21) is obtained,
The missing amount e of the phosphor during misland inking can be calculated inversely by the light amount ratio.

In the above embodiment, only the chipping amount e of the phosphor 8 was determined, but the chipping direction can also be measured based on the horizontal and vertical wobbling current values that result in a just-landing state.

Further, in the above embodiment, a CCD element is used as the light sensor section 11 for detecting the amount of light, but other light receiving elements such as a photosensor may be used, and the same effects as in the above embodiment can be obtained.

In addition, the vertical and horizontal wobbling coils 13 and 14 are
Although an example is shown in which it is installed around the optical sensor section 11, CRT
It may be attached around the neck part of l or around the tube surface.

〔Effect of the invention〕

As described above, according to the present invention, the misland ink between the phosphor and the electron beam is detected by detecting the amount of light in the misland ink state and in the just landing state obtained by forcibly moving the electron beam. Since the structure is configured to calculate the amount of missing phosphor, it is possible to perform highly accurate measurement using a device with a simple configuration compared to conventional measurement by visual inspection and measurement by image processing. By using this method, the effect of automatically performing measurements can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a method for measuring the amount of missing phosphor using a misland ink according to an embodiment of the present invention, FIG. 2 is a front view of the optical sensor section, and FIG. A configuration diagram explaining the landing state, Fig. 4 is an arrangement diagram of the phosphor in the sensor detection area, Fig. 5 is a characteristic diagram showing the relationship between wobbling current and light intensity, and Fig. 6 is a diagram showing the relationship between the phosphor and the electron beam. A configuration diagram showing the relationship, FIG. 7 is a characteristic diagram showing the relationship between the light emitting area and the amount of chipping of the phosphor, and FIG. 8 (a+,
(bl is a block diagram showing the conventional method for measuring the amount of missing phosphor using Misland ink, and FIG. 9 is a block diagram showing the camera input image in the conventional method. 1 is cg'r1B, and 10 is the electron beam. 11 is the optical sensor unit, 12 is the measuring device, 13 is the vertical wobbling coil, 14 is the horizontal wobbling coil, 15 is the sensor detection area, and e is the amount of missing phosphor. Note that the same symbols in the figures are the same. or a corresponding portion.

Claims (1)

[Claims] A tube surface light intensity measurement step of measuring the amount of light emitted by the phosphor emitted in a predetermined detection area of the tube surface in a state where electron beam mislanding occurs on the phosphor on the tube surface of the cathode ray tube; and the above-mentioned detection. Calculated based on the landing position movement step of forcibly moving the electron beam to the landing position where the light intensity of the phosphor emitting light in the area is maximum, and the ratio of the light intensity measured in the mislanding state to the above maximum light intensity. A method for measuring the amount of chipping of a phosphor by mislanding, comprising: calculating the amount of chipping of the phosphor by performing a predetermined calculation using the light emitting area of the phosphor in a mislanding state.