JP2001093411A - Method for assembling structure body of shadow mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for assembling a structural body of a shadow mask wherein precision in assembling a clearance between the inner surface of a face panel and a shadow mask is improved so as to decrease dispersion of Q-value. SOLUTION: A method for assembling a structural body of a shadow mask comprises a step of computing a suitable height of a shadow mask by using values of heights of an internal plane of a face panel 22 which are measured at many points as well as a standard value between an internal plane 22a of the face panel and a shadow mask 27, and decide a position to weld a mask frame 28 by approximating the position to the height of the shadow mask then weld the mask frame, a step of measuring Q-value of the face panel 22 to which a structural body 29 of the shadow mask is attached after being welded, and a step of correcting the position of the mask frame 28 of the face panel by feeding back a difference between the measured Q-value and the standard value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of assembling a shadow mask assembly mounted on a color picture tube, a color display tube, and the like, and more particularly, to improving the assembly accuracy of the distance between the inner surface of a face panel and a shadow mask. And a method of assembling the shadow mask structure.

[0002]

2. Description of the Related Art A color cathode ray tube 21 suitable for displaying an image such as a computer terminal display or a high-definition television.
Has the structure and function as shown in FIG. That is, it has a bulb 25 in which the face panel 22 and the funnel 23 are integrally joined by the frit glass 24, and phosphors that emit green, blue, and red light are arranged in the form of dots or stripes inside the face panel 22. A phosphor mask 26 provided is applied and formed, and behind the phosphor screen 26, a shadow mask structure 29 in which a shadow mask 27 in which a number of electron beam passage holes are formed is welded and fixed to a mask frame 28, a panel is provided. It is arranged at a fixed interval from the inner surface. An electron gun 31 that emits three electron beams is provided in the neck portion 30 of the funnel. Then, electron beams corresponding to green, blue and red selected by the shadow mask 27 are irradiated on the respective fluorescent films to emit light, thereby displaying an image.

As shown in an enlarged sectional view of a main part of FIG. 3, a shadow mask structure 29 includes a skirt portion 27a formed by bending a peripheral portion of a shadow mask 27 and a side wall portion 28a of a frame-shaped mask frame 28. It is formed by positioning and welding. Outside the three side walls 28a of the mask frame 28, a total of three or four hook springs 32 made of elastic metal pieces are fixedly welded on each side (hereafter, three hooks 32 are used for convenience). To explain).
A mounting hole (not shown) is formed at the tip of the hook spring 32. The stud pins 33 planted at several places on the inner side wall of the face panel 22
, The shadow mask structure 29 is fixed to the face panel 22.

The distance between the inner surface 22a of the face panel 22 and the shadow mask 27 is generally called a Q value. The Q value greatly affects the landing of the electron beam after assembling the cathode ray tube, and stabilization of the Q value is an important item for the quality of a color cathode ray tube such as purity and white uniformity. In recent years, demands for flatness, high definition, high luminance, and the like have been increasing, and improvement of purity and white uniformity has become a major issue. There are various causes of the inconvenience of the Q value. In particular, the inner surface height of the face panel fluctuates, the side wall portion 28a of the mask frame 28 during welding, and the skirt portion 27 of the shadow mask 27.
This is due to the assembly accuracy such as the displacement of the overlapped portion with a. Therefore, it is necessary to assemble the shadow mask structure 29 in consideration of the fluctuation of the inner surface height of the face panel 22.

A conventional method and apparatus for assembling a shadow mask structure will be described with reference to the drawings. FIG. 4 is an enlarged sectional view of a main part of an inner surface height measuring device of the face panel 22 (that is, an interval measuring device between the inner surface 22a of the face panel 22 and the stud pin 33), and FIG. 5 is an assembly of the shadow mask structure. It is an important section enlarged sectional view of a device. First, measurement of the inner surface height of the face panel 22 will be described. As shown in FIG. 4A, the side of the face panel 22 is placed on the panel support 34, and the panel support 34 is moved to a predetermined position on the inner surface height measuring device 35 by a drive mechanism (not shown). Next, as shown in FIG. 4B, the panel receiving base 34 is lowered to move the stud pins 33 of the face panel 22 through the tapered guide grooves 36b formed in the locator 36 of the inner surface height measuring device 35. Recess 36a (FIG. 4)
(C)), and then the panel receiving base 34 is further lowered to be separated from the face panel 22, and the face panel 22 is supported by the locator 36. Here, the concave portion 36a
Can be a through hole. A tension (not shown) is applied to the locator 36 by a spring (not shown) toward the concave surface 36a.

Next, with reference to a plane 33a formed by three stud pins 33 planted on three sides of the face panel 22, a distance from the panel inner surface 22a (panel inner surface height) is determined by a dial gauge. Alternatively, a plurality of designated locations (for example, as shown in FIG. 6A, one location at the center of the panel and four locations at the diagonal periphery, as shown in FIG. Alternatively, as shown in FIG. 6 (b), the measurement is performed at nine places where four places at the center of each side between the above four places are added. A desired mask height yn is obtained using the measured value xn of the panel inner surface height, and a desired welding position zn of the mask frame 28 with respect to the shadow mask 27 is determined using a predetermined approximate expression so as to obtain the mask height yn. (Positions z1, z2,
z3) (not shown) is determined. Here, the mask height yn is based on the hook spring 32 of the plane frame 33a and thus of the mask frame 28, and as shown in FIG. 3, the standard value of the distance between the inner surface 22a of the face panel 22 and the shadow mask 27. Is Q0n, yn = xn-Q
It is given by 0n.

Next, a method of assembling the shadow mask structure will be described. In the apparatus for assembling a shadow mask structure shown in FIG.
At the same time, the three support pins 42 formed on the three sets of positioning mechanisms 40 are inserted into mounting holes (not shown) of three hook springs 32 welded to the mask frame 28, respectively. In the state of being inserted and fixed, the side wall portion 28a of the mask frame 28 and the skirt portion 27a of the shadow mask 27 are overlapped at a provisional position. Next, the inner surface height xn measured by the inner surface height measuring device 35 of FIG.
Each pulse motor 43 of the frame positioning mechanism 40 is controlled using the welding position zn calculated from
2 up and down to adjust the mask frame to a predetermined position,
The overlapping portion is welded to obtain a shadow mask structure 29.

[0008]

In the above-described conventional method of assembling a shadow mask structure, a desired mask frame position is calculated from a measured value of the inner surface height of the face panel and a standard value of Q. To control the frame positioning mechanism to adjust the frame position to a predetermined position,
Since the overlapped portion was welded, the Q value of the completed shadow mask structure was very close to the standard value. However, in recent years, there has been a growing demand for flattened color display tubes, higher definition, and higher brightness.
Improvements in purity and white uniformity have been demanded, and the stabilization of the Q value has been an issue. However, in the above-described conventional assembling method, the assembling accuracy is insufficient, and the variation in the Q value cannot be ignored.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of assembling a shadow mask structure in which the assembling accuracy is further improved and the variation in Q value is reduced.

[0010]

According to the present invention, there is provided a method for assembling a shadow mask structure using a measured value of an inner surface height at a plurality of positions of a face panel and a standard value of a distance between the inner surface of the face panel and the shadow mask. The desired shadow mask height is calculated, the position of the mask frame with respect to the shadow mask is determined by approximating the shadow mask height, and the welding process is performed, and the inner surface of the face panel and the shadow mask on which the welded shadow mask structure is mounted. Measuring the distance between the mask frame and the difference between the measured value of the distance and the standard value of the distance, after performing statistical processing as necessary, and then feeding back to correct the position of the mask frame with respect to the next face panel. It is characterized by the following. With this method, the actual position of the Q value is fed back to correct the welding position.
It is possible to provide a shadow mask structure in which the assembling accuracy is improved and the variation in the Q value is reduced as compared with the related art.

In the method of assembling a shadow mask structure according to the present invention, the measured value of the inner surface height of the preceding face panel is xn (1), and the standard value of the distance between the inner surface of the face panel and the shadow mask is Q0n. Then, the shadow mask height yn (1) is yn (1) = xn (1) -Q0n, and the initial shadow mask height of the subsequent face panel is y.
n (2), and the corrected shadow mask height is Yn (2)
The height of the shadow mask is corrected using Yn (2) = yn (2) + ΔQn (1) (where ΔQn (1) is the measured value Qen (1) of the preceding face panel and the standard value Q
.DELTA.Qn (1) = Qen (1) -Q0n. And) correcting the position of the mask frame. According to this method, correction can be effectively performed by a simple method. It should be understood that (1) and (2) above not only indicate individual face panels, but also each indicate a plurality of face panels.

Further, Yn (2) = αn (1) xn (1) + yn (2) expressed by a linear expression relating to xn (1) (where correction coefficient αn (1) = ΔQn (1) / xn (1)) to correct the shadow mask height yn (2) of the subsequent face panel. According to this method, correction can be effectively performed by a simple method.

Further, each step is automatically performed on a line. This method enables mass production of a shadow mask structure with improved Q value assembly accuracy.

The distance between the inner surface of the face panel of the shadow mask structure after welding and the shadow mask is measured by a laser focus displacement meter. According to this method, the actual measurement of the Q value is facilitated, and a shadow mask structure with improved assembly accuracy of the Q value can be provided.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a basic method for assembling a shadow mask structure according to the present invention will be described with reference to the drawings. FIG. 1 is a main part flowchart for explaining a process of assembling a shadow mask structure on an automated transport line. Hereinafter, each step will be described with reference to FIG.

Step (1) —Measurement of Panel Inner Surface Height First, the face panel 22 (for example, No. 1 panel) that has been put in advance is converted into an inner surface height as shown in FIG. The stud pin 33 formed on the inner surface of the face panel 22 is supported by a locator 36. Next, based on a flat surface 33a formed by three stud pins 33 implanted on three sides of the face panel 22, a distance from the panel inner surface 22a (panel inner surface height) is determined by a dial gauge or digital side. Measurement is performed on a plurality of designated locations (for example, nine positions P1 to P9 shown in FIG. 6) by a measuring device 37 such as a long device. The obtained nine sets of measured values xn (1) are stored in the computer. (1) is No. Indicates that the data is for one panel.

Step (2) Calculation of Mask Height and Frame Welding Position Next, the measured value xn (1) of the panel inner surface height, and the distance between the inner surface 22a of the face panel 22 and the shadow mask 27 at each position And nine standard mask heights yn (1) corresponding to the inner surface shape of the panel are calculated by a computer from a predetermined equation (yn = xn-Q0n) using the standard values Q0n (Q01 to Q09). (1) is No. Indicates that the data is for one panel. Where yn (1) is the plane 33
This is the mask height at each position based on a. Desirable welding positions zn of the mask frame 28 with respect to the shadow mask 27 (welding positions z1, z2, z3 on three sides of the frame) are calculated so as to obtain the mask height yn (1). Various approximations can be used for the calculation. The mask height yn (1) may be a numerical value based on the frame bottom surface 28b instead of the plane 33a. In this case, as shown in FIG. 3, a value obtained by adding the distance k between the plane 33a at the stud pin position and the mask bottom surface 28b to xn (1) is used as the measured value of the panel inner surface height.

Step (3): Position Control and Welding of Mask and Frame Next, information on the welding position zn is input to the shadow mask assembly assembling apparatus shown in FIG. In the assembling apparatus shown in FIG. 5, the shadow mask 27 is sandwiched and fixed between the upper and lower platens 38 and 39, and the support pin 42 is inserted and fixed into a mounting hole (not shown) of the hook spring 32 welded to the mask frame 28. In this state, the side wall portion 28a of the mask frame 28 and the skirt portion 27a of the shadow mask 27 are overlapped at a temporary position. Then, using the welding position zn, the three sets of frame positioning mechanisms 40 are controlled to adjust the positions of the three sides of the frame to the respective optimum positions, and the overlapping portion with the shadow mask is welded to form the shadow mask structure 29. obtain.

Step (4). Attach the shadow mask structure to the panel. Attach a mounting hole (not shown) formed at the tip of the hook spring 32 formed outside the three side wall portion 28a of the mask frame 28. The shadow mask structure 29 is fixed to the face panel 22 by fitting it to a stud pin 33 planted at a corresponding position on the side inner wall of the face panel 22 whose inner surface height is measured by a method similar to the conventional method. .

Step (5): Measurement of Panel-Mask Interval (Q Value) Face Panel 22 with Shadow Mask Structure 29 Mounted
The distance between the inner surface of the face panel and the shadow mask is measured at nine positions in FIG. 6 from the front side of the camera using a laser focus displacement meter (not shown), and the obtained nine sets of measured values Qen (1) are sent to a computer. Remember.
(1) is No. Indicates that the data is for one panel.

Step (6) Detection of difference between measured value of Q value and standard value Difference ΔQn (1) between measured value Qen (1) and standard value Q0n at each measurement position (= Qen (1) -Q0n) is calculated.
Further, an average value ΔQav (1) of the difference ΔQn (1) is also calculated. (1) indicates that the data is for the preceding panel. When Qen (1)> Q0n, ΔQn (1)> 0, and when Qen (1) <Q0n, ΔQn (1) <0.

Step (7): Correction of mask height and correction of frame welding position As shown by the broken line in FIG. 1, the difference ΔQn (1) between the Q values calculated in Step (6) is converted to Step (2). To correct the mask height of the subsequently input face panel (eg, No. 2 panel). First, no. 2
Regarding the panels, In step (1), the panel inner surface height xn (2) was measured in the same manner as in the case of the panel No. 1; Mask height yn (2) = xn (2) -Q0n before correction for two panels
Is calculated. Next, Q0n is corrected to a correction value (Q0n-ΔQn
No. (1)). The corrected mask height Yn (2) for the two panels is given by the following equation: Yn (2) = xn (2)-(Q0n
−ΔQn (1)) = (xn (2) −Q0n) + ΔQn (1)
= Yn (2) + ΔQn (1). This equation gives N
o. Initially specified mask height yn (2) for two panels
Of the preceding No. This is corrected by the difference between the Q values of one panel. Here, when the measured value Qen (1) is larger than the standard value Q0n, the Q value is corrected in a decreasing direction. in this case,
Since ΔQn (1)> 0, the corrected (Q0n−ΔQn)
(1)) is smaller than Q0n by ΔQn (1). Conversely, if the measured value Qen (1) is smaller than the standard value Q0n, Q
Correct the value in the increasing direction. In this case, ΔQn
(1) Since <0, the corrected (Q0n−ΔQn)
(1)) is larger than Q0n by -ΔQn (1).
As another correction method, the correction may be uniformly performed using the average value ΔQav (1) instead of ΔQn (1). in this case,
Yn (2) = yn (2) + ΔQav (1) will be used.

Next, the corrected welding position Zn (2) of the mask frame 28 with respect to the shadow mask 27 so as to be as close as possible to the corrected mask height Yn (2).
(Welding positions Z1, Z2, Z3 on three sides of the frame) are calculated. There are various approximate expressions for obtaining Zn (2). The information on the corrected welding position Zn (2) is input to the assembling apparatus for a shadow mask structure shown in FIG. 5, and welding is performed in the same manner as in step (3) to obtain a shadow mask structure.

Next, the above-mentioned shadow mask structure that has been corrected and welded is referred to as No. 1. After mounting on two panels and measuring the panel-mask distance Qen (2), the panel is conveyed to the next step. No.
The Q value of No. 2 panel is No. The variation is improved compared to the Q value of one panel. Panel-mask spacing measurement Qen
(2) can be used for further correction.

Similarly, the difference between the Q values of the preceding face panel is fed back, and the mask height and welding position of the subsequent face panel can be sequentially improved.

As another correction method, the difference ΔQn (1) between the measured value of the distance (Q value) between the inner surface of the face panel and the shadow mask and the standard value is, as shown in the above equation, the height of the inner surface of the panel. Is a function of the panel inner surface height xn (1) multiplied by the correction coefficient αn (1) (αn
(1) xn (1)). Therefore, the corrected mask height Yn (2) is Yn (2) = yn.
(2) + ΔQn (1) = αn (1) xn (1) + yn (2)
Can be displayed with. Here, the correction coefficient αn (1) = ΔQn
(1) / xn (1). That is, the corrected No.
The mask height Yn (2) of the second panel is No. 2 before correction. 2
The mask height yn (2) of the panel is defined as a constant term. 1
It can be expressed by a linear expression relating to the measured value xn (1) of the inner surface height of the panel. Similarly, the following N
o. The corrected mask height of the three panels is Yn (3) = αn
(2) xn (2) + yn (3) can be displayed. Here, the correction coefficient αn (2) = ΔQn (2) / xn (2). Hereinafter, similarly, the correction coefficient αn calculated from the data of the preceding panel
Can be used to sequentially correct the mask height of subsequent panels.

In order to improve the accuracy of correction of the mask height, the corrected mask height Yn can be expressed as a quadratic expression relating to xn, or as a multiple-order function. In addition, the correction can be performed with the average value ΔQav instead of ΔQn. In this case, the correction coefficient is represented by αn = ΔQav / xn.

In the above correction method, the difference ΔQn between the measured value of the Q value and the standard value is detected for one panel (for example, No. 1), and this is used to correct the subsequent panel. For example, ΔQn is detected for N (for example, N = several tens) panels each time a lot is switched, and (N + 1) number is obtained by using a numerical value obtained by statistically processing N ΔQn. The correction accuracy can be improved by correcting the subsequent panels thereafter. All of these steps can be automated.

In the above-described method of assembling the shadow mask structure of the present invention, the height of the inner surface of the face panel is measured at a plurality of locations, a desired mask height is calculated from the measured values, and the welding position of the mask frame is further determined. The distance between the inner surface of the face panel on which the shadow mask structure after welding is mounted and the shadow mask is measured, and this is fed back to correct the welding position of the mask frame. The measuring method, correction formula, data processing method, and the like are not limited to the above, and various methods are possible.

According to the method of assembling the shadow mask structure of the present invention, the variation of the Q value after welding is reduced by the conventional method.
It has been confirmed that the variation of the value is reduced to ± 80 μm with respect to ± 200 μm.

[0031]

According to the method of assembling a shadow mask structure of the present invention, a desired shadow is obtained by using the measured values of the inner surface heights of a plurality of preceding face panels and the standard value of the distance between the inner surface of the face panel and the shadow mask. Calculate the mask height, determine the position of the mask frame with respect to the shadow mask by approximating the height of the shadow mask, and perform the welding process, and the distance between the inner surface of the face panel on which the shadow mask structure after welding is mounted and the shadow mask And correcting the position of the mask frame of the subsequent face panel by feeding back the difference between the measured value of the interval and the standard value. According to this method, the welding position is corrected by feeding back the actually measured value of the Q value, so that it is possible to provide a shadow mask structure with improved assembling accuracy and reduced variation in the Q value as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a method of assembling a shadow mask structure according to the present invention.

FIG. 2 is a side view including a partial cross-sectional view of a conventional color cathode ray tube.

FIG. 3 is a partial cross-sectional view showing a state in which a shadow mask structure is attached to a face panel.

FIG. 4 is an enlarged sectional view (a, b) of a main part of a face panel inner surface height measuring device and a perspective view (c) of a locator.

FIG. 5 is an enlarged sectional view of a main part of a conventional shadow mask assembly apparatus.

FIG. 6 is a plan view of a face panel showing measurement points ((a) is 5 places, (b) is 9 places).

[Description of Signs] 1 Step (1): Measurement of panel inner surface height 2 Step (2): Calculation of mask height and welding position 3 Step (3): Control of mask frame position and welding 4 Step (4) 5) Step (5): Measurement of panel-mask interval (Q value) 6 Step (6): Calculation of difference between measured value of Q value and standard value 7) Step (5) 7) Correction of mask height and frame welding position 22 Face panel 27 Shadow mask 28 Mask frame 29 Shadow mask structure

Claims (5)

[Claims] 1. A desired shadow mask height is calculated using a measured value of the inner surface height of a plurality of preceding face panels and a standard value of an interval between the inner surface of the face panel and the shadow mask. Determining the position of the mask frame with respect to the shadow mask so as to be, a step of welding, a step of measuring an interval between the inner surface of the face panel on which the welded shadow mask structure is mounted and the shadow mask, and a measured value of the interval. Correcting the position of the mask frame with respect to the subsequent face panel by feeding back a difference from the standard value of the interval, and assembling the shadow mask assembly. 2. Assuming that the preceding measured value of the inner surface height of the face panel is xn (1) and the standard value of the distance between the inner surface of the face panel and the shadow mask is Q0n, the shadow mask height yn (1) is yn (1) = xn (1) -Q0n, the initial shadow mask height of the subsequent face panel is yn (2), and the corrected shadow mask height is Yn.
As (2), the height of the shadow mask is corrected using Yn (2) = yn (2) + ΔQn (1) (however, ΔQn
(1) is the difference between the measured value Qen (1) of the preceding face panel and the standard value Q0n, and ΔQn (1) = Qen (1) −Q0n.
It is. 2. The method according to claim 1, wherein the position of the mask frame is corrected. 3. Yn represented by a linear expression relating to xn (1)
(2) = αn (1) xn (1) + yn (2) (where the correction coefficient αn (1) = ΔQn (1) / xn (1))
3. The method for assembling a shadow mask structure according to claim 2, wherein the height yn (2) of the subsequent face panel is corrected using the following. 4. The method according to claim 1, wherein each step is automatically performed on a line. 5. The assembly method according to claim 1, wherein the distance between the inner surface of the face panel of the shadow mask structure after welding and the shadow mask is measured by a laser focus displacement meter.