JP3409361B2 - Electron gun cathode assembling apparatus and method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for assembling an electron gun cathode and a method for assembling the same, and more particularly, to a high accuracy capable of maintaining a predetermined distance between the first grid and the cathode of an electron gun for a color cathode ray tube. The present invention relates to a quality electron gun cathode assembling apparatus and an assembling method thereof.

[0002]

2. Description of the Related Art Generally, an electron gun for a cathode ray tube has a cathode,
It has a plurality of electrodes arranged in a predetermined relationship such as a grid for controlling electron emission from the cathode to form an electron beam and a grid for focusing and accelerating the electron beam emitted through the grid. A plurality of electrodes are formed in a structure fixed by an insulating support.

In such an electron gun, a so-called bead mount is assembled by integrally fixing a cathode support for attaching a cathode to an insulating support in advance, and then a so-called bead mount is assembled, after which electron emission from the cathode is controlled. First to do
It is assembled by mounting the cathode on the cathode support so that the cathode is spaced a predetermined distance from the grid.

As shown in FIG. 9, the assembly of the electron gun cathode has hitherto been performed by penetrating the tip of the air micro-nozzle 20 of the air micrometer through the opening of the first grid (G1) while insulating the same. Support (ceramic disc)
The reference surface at the tip of the dami gauge is brought into close contact with the first grid by penetrating the cathode support of the cathode fixed to the air micro nozzle 20.
After adjusting the position so that the tip end of the cathode becomes equal to the G1-K interval, the cathode is welded to the cathode pin 24 via the V tab 22 with reference to the air micro nozzle 20. This welding is usually resistance welding. Although not shown, an A / E (air electric) converter, a regulator and the like are usually connected to the air micro nozzle.

[0005]

The method of assembling the electron gun cathode by measuring the distance between the first grid and the cathode using the air micrometer 20 as described above has the following problems.

1) Since air is blown onto the oxide surface of the cathode, the oxide is scattered, and a recess is formed especially in the center of the cathode.

2) When the air nozzle is inserted through the opening of the first grid, nozzle marks and deformation occur near the opening of the first grid.

3) There is a limit to the processing for reducing the diameter of the air nozzle, and it is difficult to manufacture the air nozzle capable of dealing with the opening diameter of the first grid of 0.4 mm or less.

In view of the above problems, the present invention provides an electron gun cathode assembling apparatus and an electron gun cathode assembling apparatus capable of measuring and maintaining the distance between the first grid (G1) constituting the electron gun of the cathode ray tube and the cathode with high accuracy. An object is to provide an assembling method.

[0010]

SUMMARY OF THE INVENTION According to the present invention, the above-mentioned problem is solved by the first grid holding means for fixing and holding the first grid forming the electron gun of the cathode ray tube, and the first grid holding means for holding the cathode. While measuring the position of the cathode sleeve holding means slidable in the grid direction and the first grid fixedly held by the first grid holding means ,
Measuring the position of the cathode to be held in the cathode sleeve holding means, the cathode or from said first grid
Includes an auto-focus distance measurement device for measuring the distance between the first grid and the cathode sleeve and the first grid distance is provided with the cathode at the time when a predetermined value between the cathode in And a laser welding means for joining the first grid assembly to the electron gun cathode assembly apparatus. Further, the first holding means fixedly holds the first grid forming the electron gun of the cathode ray tube, and the second holding means slidable in the first grid direction holds the cathode. Measures the position of the first grid fixedly held by an autofocus distance measuring device
And, the position of the cathode to be held in the second holding means
Is measured by the autofocus distance measuring device,
The distance between to the cathode from the first grid to measure the distance between the first grid and the cathode is moved to the second holding means to a predetermined value, a cathode sleeve the first grid This is solved by a method for assembling an electron gun cathode, which comprises joining the first grid assembly provided with laser welding means.

In the apparatus for assembling an electron gun cathode and the method for assembling the same according to the present invention, it is preferable that the autofocus distance measuring apparatus uses a semiconductor laser as a light source.

[0012]

According to the apparatus for assembling the electron gun cathode and the method for assembling the same according to the present invention, the distance between G1 and the cathode (cathode sleeve), that is, the distance between the G1 and the cathode (cathode sleeve), is optically measured with high accuracy in a non-contact manner. Since G1 and the cathode can be welded and assembled in this state, scattering of oxide 3 on the cathode is prevented and damage to G1 is prevented. Moreover, since the distance is measured by the laser light, if the spot light is narrowed down, the G1 aperture diameter can be up to about 0.3 mm.

[0013]

Embodiments of an electron gun cathode assembling apparatus and method according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of an apparatus for assembling an electron gun cathode according to the present invention.

As shown in FIG. 1, the apparatus for assembling an electron gun cathode according to the present invention comprises the following four elements.

A. First grid (G1) / cathode sleeve holder B. Auto focus distance measuring device C. Laser emission unit D. Laser Welding Controller Section Before describing the electron gun cathode assembling apparatus of this embodiment in detail, the electron gun cathode section will be described with reference to FIG.

As shown in FIG. 2A, the first grid (G1) is made into a G1 assembly 1 by silver brazing to form a hole 2 in the G1.
A cathode sleeve 4 provided with an oxide (oxide) 3 is set in the vicinity to form an electron gun cathode portion. G1
The -K (cathode) interval is shown in Fig. 2 (b) by A in Fig. 2 (a).
As shown in a partially enlarged view, the outer surface of G1 and oxide 3
With a distance to the surface, in this embodiment, the cathode sleeve 4 and the G1 assembly 1 are joined by laser welding at a predetermined position.
The distance between the inner surface of G1 and oxide 3 is about 0.01 m.
m.

[0017] Figure 3 is a cathode sleeve before joining arrangement illustration of the G1 assembly, the height measurement points on the oxide 3 the front surface from the surrounding points (three places) of the opening 2 of the G1 assembly 1 of G1 The distance 1 to (one place) is measured by the autofocus distance measuring device shown below. The cathode sleeve 4 is moved upward and set at an imaginary line portion.

The four constituent elements of the electron gun cathode assembling apparatus according to the present invention will be described below. First grid / cathode holding portion, B.I. Autofocus distance measuring device section, C.I. Laser emitting unit, D.I. The laser welding controller section will be described in order with reference to the configuration diagram shown in FIG.

First, A. In the first grid (G1) cathode sleeve holder, an XY precision table 9 driven by a biaxial motor is fixed on the base 100. A fixed portion of a Z precision table 10 driven by a motor is fixed to a movable portion of the XY precision table 9, and a cathode sleeve chuck 11 is fixed to the movable portion via an air slider 15. A collet mechanism 110 is provided on the cathode sleeve chuck 11 so as to fix the cathode sleeve 4.

For the movable part of the XY precision table 9,
The G1 holding part 5 is fixed, and as shown in FIG. 5 of the G1 assembly / cathode sleeve holding part detailed view, above the cathode sleeve chuck 11, there is a table on which the G1 assembly 1 is placed.
Further, the fixed portion of the air cylinder 7 is screwed to the G1 holding portion 5, and the leaf spring 6 is screwed to the movable portion, so that the G1 assembly 1 is held from above when the air cylinder 7 is contracted. ing.

Next, B. In the autofocus distance measuring device section, a fixed part of a Z precision table 101 driven by a motor is screwed onto a base 100, and a movable part is
An autofocus distance measuring device 12 to which a 20 × objective lens is attached is attached. Further, the tip of the distance measuring length measuring part 13 attached to the fixed side of the Z precision table 101 is in contact with the length measuring piece 102 fixed to the movable part of the Z precision table 101.

The autofocus distance measuring device 12 is shown in FIGS. 7 and 8 for explaining the principle of the autofocus device (I).
And (II), a knife edge method is adopted, and an optical system (for example, a collimator 402, a half mirror 403, an objective lens 404, a knife edge 40) using a laser diode 401 as a semiconductor laser as a light source is adopted.
5, a light receiving element (for example, a two-divided diode 406) and an electric circuit (for example, although not shown, for example, a current-voltage converter and a differential amplifier), a length measuring device, and the optical axis direction of the position with respect to the just focus position. The deviation amount is calculated and output as an electric amount or a numerical value.

Further, the camera 301 is provided, and the state of the beam can be monitored by the TV monitor 302.

The principle of the knife edge method adopted in this autofocus distance measuring device is based on the laser diode 4
The reference light emitted from 01 is autofocused via the objective lens 404 which is sent to the objective lens 404 via the collimator 402 and the half mirror 403. At this time, the scattered light of the half mirror 403 obtains three states of underfocus, just focus, and overfocus by the knife edge 405. The Z coordinate of the autofocus measuring device when the output of the photodiode that is just focused is 0 is the height of the object (FIG. 8). The G1-K interval was measured using this principle.

C. Laser emission unit is G1 assembly 1
Three laser emission units are attached to the base 100 toward the center of G1 at positions a, b, and c (see FIG. 6) that divides the circumference into three below the base of the cathode sleeve 4. It is configured to join the G1 assembly 1.

The autofocus distance measuring device controller 300 moves the Z precision table 101 to which the autofocus distance measuring device 12 is attached based on the operation command from the computer 14 to move the Z precision table 1.
The movable part 01 is moved closer to or farther from the G1 assembly 1.

The computer 14 receives a numerical value proportional to the amount of deviation of the position with respect to the just focus position measured by the autofocus distance measuring device 12 in the optical axis direction, and when the numerical value approaches a preset numerical value, it is just adjusted. It has the function of recognizing the focus position.

The sequencer 310 takes charge of general control of the above-mentioned A, B, and C mechanical parts, and the position control unit 311.
Manages the motor driver 320 with the unit attached to the sequencer 310 and controls the precision table 9, 1
Move 0.

D. The laser welding controller is connected to the laser emitting unit C and issues a welding instruction when G1-K is controlled at a predetermined interval.

The method of assembling the electron gun cathode will be described below with reference to FIG.
The operation procedure of the electron gun cathode assembling apparatus of the above embodiment will be described with reference to FIG.

First, the G1 assembly 1 made by silver brazing the first grid G1 is put into the G1 holding portion 5 on the XY precision table 9, and the G1 assembly is assembled from above by the leaf spring 6 via the cylinder 7. Fix the item.

Next, the cathode sleeve 4 is placed on the XY precision table 9 and the Z precision table 10, and the collet mechanism 1 is provided.
It is put into the cathode sleeve chuck 11 having 10 and the collet is opened and pinched and fixed.

Next, the G1 assembly 1 and the cathode sleeve 4
The XY precision table 9 is moved under the autofocus distance measuring device 12 while fixing the above-mentioned state.

After that, the height of three equal positions (FIG. 6) is measured by the autofocus distance measuring device 12 at 120 ° on the circumference of about 0.75 mm of the opening 2 of the first grid G1. The measured data is transferred from the length measuring unit 13 to the computer 14, and the average of the heights of three points is calculated.

G1 arbitrarily determined from the calculated data
The autofocus distance measuring device 12 is lowered to a position below the −K interval (about 210 μm to 230 μm), and the cathode sleeve 4 is raised from below so that the position of the autofocus distance measuring device is in focus. First,
The air slider 15 is used to raise it by about 10 mm, and then the Z precision table 10 is raised and stopped at the just focus position. First air slider 15
The reason why the Z precision table 10 is used to move all distances is that it takes a long time.

At this position, the G1 assembly 1 and the cathode sleeve 4 are joined together by laser welding (120 ° equally divided three points). In this way, the cathodes are assembled at arbitrary G1-K intervals.

Finally, the autofocus distance measuring device is returned to the origin position, the cathode sleeve chuck 11 and the leaf spring 6 are released, and the finished product is taken out.

In this way, it becomes possible to assemble a high-quality electron gun cathode which maintains the G1-K interval with high accuracy.

[0039]

As described above, the electron gun cathode assembling apparatus according to the present invention measures the position of the first grid.
By measuring the position of the cathode as well as a constant, set the autofocus distance measuring device for measuring the distance between the first grid to the cathode only, the distance measured by the autofocus distance measuring device becomes a predetermined value At this point, the cathode sleeve and the first grid assembly are joined together. With this configuration, the first of the electron gun
The spacing (G- between the grid (G1) and the cathode (K)
Since the (K interval) can be measured in a non-contact manner, the problems such as the deformation of G1 and the dent of the oxide surface, which have occurred conventionally, are eliminated. Further, according to the method of assembling the electron gun cathode according to the present invention, after the first grid constituting the electron gun of the cathode ray tube is fixed and held by the first holding means, the second grid slidable in the first grid direction is used. holding the cathode by the holding means, the by O over autofocus distance measuring device after its
Measure the position of one grid, measure the position of the cathode
Te, the distance between the first grid to the cathode is measured, the distance between the first grid and cathode to move the second holding means to a predetermined value, with cathodes sleeve and first grid The first grid assembly is joined by laser welding means. Further, since the G1-K interval is measured by the semiconductor laser light, it is possible to handle up to 0.3 mm of the diameter of the G1 hole by narrowing down the spot light, and the G1-K interval can be set with high accuracy. Can be assembled by welding and can supply cathodes with excellent focus characteristics.

[0040]

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of an electron gun cathode assembly device according to the present invention.

FIG. 2 is a cross-sectional view for explaining an electron gun cathode (K) portion and a G1-K interval.

FIG. 3 is a layout explanatory diagram before joining the cathode sleeve to the G1 assembly.

FIG. 4 is a configuration diagram of an electron gun assembly apparatus according to the present invention.

FIG. 5 is a detailed view of a G1 assembly / cathode sleeve holding portion.

FIG. 6 is an explanatory diagram of a G1 plane measurement position.

FIG. 7 is a diagram (I) for explaining the principle of the autofocus device.

FIG. 8 is a diagram (II) for explaining the principle of the autofocus device.

FIG. 9 is a partial cross-sectional view for explaining a conventional electron gun cathode assembly device.

[Explanation of symbols]

1 G1 assembly 2 holes 3 oxide 4 cathode sleeve 5 G1 holding part 6 leaf spring 7 cylinders 9 XY precision table 10, 101 Z precision table 11 Cathode sleeve chuck 12 Autofocus distance measuring device 13 Length measurement section 14 Computer 15 air slider 20 air micro nozzle 21 Ceramic disc 22 V tab 24 K pin 26 Sleeve suction pin 300 Autofocus distance measuring device controller 310 Sequencer 311 Position control unit 320 motor driver 401 laser diode 402 Collimator 403 Half mirror 405 knife edge

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01J 9/18

Claims (2)

(57) [Claims] 1. A first grid holding means for fixing and holding a first grid constituting an electron gun of a cathode ray tube; a cathode sleeve holding means for holding a cathode and slidable in the first grid direction; The position of the first grid fixedly held by the first grid holding means is measured, and the position of the cathode held by the cathode sleeve holding means is measured.
Te, the cathode in which the autofocus distance measuring device for measuring the distance between to the cathode from the first grid, the distance between the first grid and the cathode provided with the cathode at the time when a predetermined value An electron gun cathode assembly apparatus comprising: a laser welding means for joining a sleeve and a first grid assembly including the first grid. 2. A first holding means fixedly holds a first grid forming an electron gun of a cathode ray tube, and a second holding means slidable in the first grid direction holds the cathode, The first grid fixedly held by holding means
The position of is measured with an autofocus distance measuring device,
The position of the cathode held by the second holding means is moved forward.
Serial measured by the autofocus distance measuring device, the distance between to the cathode from the first grid is measured, the second holding means so that the distance becomes a predetermined value between the first grid and cathode A method of assembling an electron gun cathode, which comprises moving and joining the cathode sleeve and the first grid assembly having the first grid by laser welding means.