JP2000077000A - Inspection device for positional deviation of electron gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection device for the positional deviation of an electron gun, capable of accurately inspecting the electron gun for its positional deviation by enabling the edge of an electron beam transmission hole to be identified clearly, and of accurately and easily setting the electron gun to the inspection position. SOLUTION: The position of an electron gun 2 on a support stage 10 is measured by a position measuring mechanism 30, and the support stage 10 is driven according to data regarding the position of the electron gun 2 obtained, to set the electron gun 2 in a predetermined inspection position. Also, the electron gun 2 is irradiated by a linearly polarized light, and the light reflected by the electron gun 2 is observed via a polarization means, thus detecting the displacement positional deviation of the electron gun 2 between grids.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun positional deviation inspection apparatus for inspecting positional deviation between grids of an assembled electron gun.

[0002]

2. Description of the Related Art An electron gun, which is provided in a cathode ray tube used for a television receiver or the like and emits an electron beam toward a phosphor screen, comprises a cathode for emitting an electron beam, and a plurality of grids constituting electrodes. have.

This electron gun is assembled such that a plurality of grids are arranged on the same axis, and a cathode is disposed in a lowermost grid (first grid) of the plurality of grids. Then, the electron gun controls, accelerates, and focuses the electron beam emitted from the cathode through each grid, irradiates a predetermined phosphor on the phosphor screen, and causes the phosphor to emit light. It has been done.

For example, in the case of a single electron gun type (a Wangan three beam system), this electron gun is composed of three bottomed cylindrical grids in which a first grid is arranged in-line, for example. Inside, a cathode for emitting an electron beam for emitting a red phosphor, a cathode for emitting an electron beam for emitting a green phosphor, and a cathode for emitting an electron beam for emitting a blue phosphor are individually disposed. ing.

[0005] Each of the three grids constituting the first grid is provided with a small electron beam transmitting hole for transmitting an electron beam emitted from a cathode housed in each of the three grids at a substantially central portion of a bottom surface thereof. I have. Further, a grid (second grid) arranged adjacent to the first grid
Is provided with three minute electron beam transmission holes on the surface facing the first grid. Then, the bottom surface of the first grid and the opposing surface of the second grid are abutted such that the electron beam transmission holes provided in the three grids alone and the electron beam transmission holes provided in the second grid coincide with each other. Thus, relative positioning between the two is achieved.

In this Wangan three-beam type electron gun, an electron beam emitted from each cathode passes through an electron beam transmitting hole, intersects at the center of a main lens constituted by a plurality of grids, and then crosses in three directions. Each discrete electron beam is refracted by an electrostatic polarizing plate and converted on a phosphor screen.

Therefore, in the electron gun configured as described above, if the assembly accuracy of each grid is poor, the shape and the trajectory of the emitted electron beam are shifted. In particular, the first grid G
As described above, the first and second grids G2 are positioned so that the minute electron beam transmission holes 100 and 101 coincide with each other, so that a positional deviation exceeding an allowable limit occurs in these as shown in FIG. And the electron beam emitted from the cathode 102 does not properly pass through the electron beam transmission hole,
A large deviation occurs in the shape and the trajectory.

[0008] When the electron gun in which the shape and the trajectory of the electron beam are displaced is mounted in the cathode ray tube, the cathode ray tube is not irradiated with the electron beam in an appropriate position on the phosphor screen in an appropriate shape. This causes image degradation.

Therefore, before the electron gun is mounted in the cathode ray tube, the assembling accuracy is evaluated, and the electron gun in which the misalignment between the grids exceeds an allowable range is removed from the cathode ray tube production line. It is necessary to prevent the cathode ray tube from being manufactured.

Inspection of such a displacement of the electron gun has conventionally been performed using a displacement inspection apparatus 110 as shown in FIG. The position shift inspection apparatus 110 shown in FIG. 10 includes an XY stage 111 that supports the electron gun 120 so as to be movable in the X-axis direction and the Y-axis direction, and illuminates the electron gun 120 supported by the XY stage 111 from the side. Fiber illuminator 112 and fiber illuminator 112
And a microscope 113 for observing the electron gun 120 illuminated by the above from above the uppermost grid through each grid and looking into the cathode provided inside the lowermost grid.

The electron gun 120 is provided with the position shift inspection apparatus 1.
10 is mounted on the mounting surface of the XY stage 111 such that the central axis is substantially orthogonal to the mounting surface.
Light is applied from the side by 12 to illuminate the space between the grids.

[0012] For example, when inspecting the displacement between the first grid G1 and the second grid G2, the edge of the illuminated electron beam transmitting hole 100 of the first grid G1 is
Each position of the second grid G2 with respect to the edge of the electron beam transmission hole 101 is observed by the microscope 113, and these positional deviations are inspected.

[0013]

However, the inspection method using the above-described conventional position shift inspection apparatus 110 is described as follows.
Because the electron gun 120 was illuminated from the side to illuminate the space between the grids, the amount of observable light with respect to the amount of illumination light was small, so-called light use efficiency was poor, and the field of view was dark. . In addition, since the field of view becomes dark, the magnification of the microscope 113 cannot be increased to observe the grid, and the displacement of the electron gun 120 cannot be accurately inspected in some cases.

In the inspection method using the conventional displacement inspection apparatus 110, the electron gun 120 is irradiated with light from the side to illuminate the space between the grids, so that the surface of the grid is uniformly illuminated. And the entire grid could not be observed evenly.

As a method of increasing the efficiency of use of the illumination light and uniformly illuminating the illumination light on the surface of the grid, and accurately inspecting the displacement, epi-illumination, that is, the illumination light is applied from the uppermost grid side of the electron gun 120. It is conceivable to irradiate in the direction along the central axis and observe the reflected light to inspect the positional deviation. However, when it is attempted to inspect the positional deviation between the first grid G1 and the second grid G2 by epi-illumination. , The illuminated electron beam transmission hole 1 of the first grid G1
00 and the edge of the electron beam transmission hole 101 of the second grid G2 cannot be clearly observed, and there is a problem that it is difficult to inspect the positional deviation.

That is, in the first grid G1 and the second grid G2, the electron beam transmitting holes 100 and 101 are formed by punching on the flat metal surface, and the electron beam transmitting holes 100 and 101 are formed. Is in a state inclined in the punching direction. Therefore, in the reflected light from the surfaces of the first grid G1 and the second grid G2 due to the epi-illumination, the amount of light reflected near the edge is very small as compared with the amount of reflected light from other portions. Has become.

Light reflected by the electron beam emitting surface of the cathode 102 disposed inside the first grid G1 through the electron beam transmitting holes 100 and 101 is reflected by the electron beam emitting surface of the cathode 102. Due to the oxide surface, the amount of light is reduced due to irregular reflection.

Therefore, when an attempt is made to inspect the displacement between the first grid G1 and the second grid G2 by epi-illumination, the light reflected near the edges of the electron beam transmitting holes 100 and 101 and the electron beam of the cathode 102 The light reflected by the emission surface is darkly mixed with the light, and the electron beam transmission holes 100, 100 of the first grid G1 and the second grid G2 are mixed.
The edge of 101 cannot be clearly distinguished.

The first grid G1 and the second grid G
In order to properly inspect the misalignment with the electron gun 2, it is necessary to accurately position the electron gun to be inspected at a predetermined inspection position on the order of μm. Since accurate positioning of the electron gun to be inspected is a very complicated operation, it has been strongly desired that the operation can be performed more easily.

The electron gun position shift inspection apparatus according to the present invention has been devised in view of the above-described conventional circumstances, and has improved light utilization efficiency to brighten the field of view and reflect light from the grid surface. By reducing the amount of light, the reflected light from the electron beam emission surface of the cathode is made relatively bright, and the edges of the electron beam transmission holes can be clearly distinguished, so that the displacement of the electron gun can be accurately inspected. It is another object of the present invention to provide an electron gun position shift inspection apparatus which can perform the positioning of the electron gun at the inspection position accurately and easily.

[0021]

SUMMARY OF THE INVENTION According to the present invention, there is provided an electron gun misalignment inspection apparatus, comprising: an electron gun supporting means for movably supporting an electron gun to be inspected; and an electron gun supporting means on the electron gun supporting means. Position measuring means for measuring the position; driving means for driving the electron gun supporting means based on the position data of the electron gun measured by the position measuring means to move the electron gun to a predetermined inspection position; A position deviation inspection means for inspecting a position deviation between grids of the electron gun at the inspection position.

In the apparatus for inspecting the displacement of an electron gun, the displacement inspection means irradiates the electron gun with linearly polarized light and observes the light reflected by the electron gun via the polarization means. Thus, the displacement between the grids of the electron gun is inspected.

The position of the electron gun to be inspected on the electron gun supporting means is measured by the position measuring means. Then, the electron gun supporting means is driven by the driving means based on the position data of the electron gun, so that the electron gun is accurately and simply positioned at a predetermined inspection position.

The electron gun positioned at the predetermined inspection position is irradiated with linearly polarized light from the position deviation inspection means. The linearly polarized light applied to the electron gun is reflected on the grid surface of the electron gun and the electron beam emission surface of the cathode.

The reflected light reflected on the grid surface is
Since the grid surface is a flat metal surface, it goes to the polarizing means while maintaining the state of linearly polarized light. A large amount of the linearly polarized reflected light reflected on the grid surface is blocked by the polarizing means according to the difference between the direction of the polarization axis and the direction of the polarization axis of the polarizing means.

On the other hand, the light reflected on the electron beam emitting surface of the cathode is diffusely reflected on the electron beam emitting surface and polarized because the electron beam emitting surface of the cathode is a fine uneven surface of oxide. It heads to the polarizing means in a state where the state has collapsed. The reflected light reflected on the electron beam emission surface of the cathode has a random deflection state, so that a substantially constant amount of light passes through the polarizing means regardless of the direction of the polarization axis of the polarizing means.

Therefore, by irradiating the electron gun with linearly polarized light and observing the reflected light reflected by the electron gun through the polarizing means, the reflected light from the electron beam emission surface of the cathode is relatively reduced. It becomes bright, and the boundary between the electron beam emission surface of the cathode and the surface of the grid can be clearly distinguished.

[0028]

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

An electron gun position shift inspection apparatus 1 according to the present invention.
As shown in FIG. 1, a support stage 10 movably supports the electron gun 2, a position measurement mechanism 30 for measuring the position of the electron gun 2 on the support stage 10, and measurement by the position measurement mechanism 30. A controller (not shown) that drives the support stage 10 based on the obtained position data of the electron gun 2 to position the electron gun 2 supported on the support stage 10 at a predetermined inspection position, and a controller that is positioned at the predetermined inspection position. And a displacement detection mechanism 40 for irradiating the electron gun 2 with linearly polarized light and detecting the reflected light.

The support stage 10 includes a support section 11 for supporting the electron gun 2, an inclination stage 14 for tilting the electron gun 2 supported on the support section 11 in a predetermined direction, and an electron gun 2 supported on the support section 11. And the electron gun 2 supported by the support unit 11 in the Y-axis direction, the X-axis direction,
It has a Y-axis stage 18, an X-axis stage 19, and a Z-axis stage 20, which are respectively moved in the Z-axis direction, and these are stacked and provided on the base 3 as an integrated moving stage.

The support section 11 has a mounting table 12 on which the electron gun 2 is mounted and a holder 13 for holding an outer peripheral portion of the electron gun 2. The mounting table 12 has a mounting surface 12a orthogonal to the Z axis, and one end of the electron gun 2 on the cathode side is supported by the mounting surface 12a. Then, the outer peripheral portion of the electron gun 2 is held by the holder 13. Thereby, the electron gun 2 is stably supported on the support stage 10 so that the center axis thereof is along the Z-axis direction.

On the side of the support portion 11 facing the base 3,
The tilt stage 14 is connected.

The tilt stage 14 includes an X-axis tilt stage 15 for tilting the support 11 at a predetermined angle with respect to the X axis, and a Y-axis tilt stage 16 for tilting the support 11 at a predetermined angle with respect to the Y axis. And The X-axis tilt stage 15 and the Y-axis tilt stage 16 are each connected to a controller (not shown), and tilt the support unit 11 and the electron gun 2 supported by the support unit 11 in the X-axis direction or the Y-axis direction under the control of the controller. Let it.

A rotary stage 17 is connected to the side of the tilt stage 14 facing the base 3. The rotary stage 17 is also connected to a controller (not shown), and rotates the tilt stage 14, the support portion 11, and the electron gun 2 supported by the tilt stage 14 around the Z axis under the control of the controller.

A Y-axis stage 18 is connected to a side of the rotary stage 17 facing the base 3. The Y-axis stage 18 is also connected to a controller (not shown),
Under the control of the controller, the rotating stage 17, the tilting stage 14, the support portion 11, and the electron gun 2 supported by the support portion 11
Is moved in the Y-axis direction.

An X-axis stage 19 is connected to a side of the Y-axis stage 18 facing the base 3. The X-axis stage 19 is also connected to a controller (not shown),
Under the control of the controller, the Y-axis stage 18, the rotary stage 17, the tilt stage 14, the support 11, and the electron gun 2 supported by the support are moved in the X-axis direction.

A Z-axis stage 20 is connected to the side of the X-axis stage 19 facing the base 3. The Z-axis stage 20 includes: a fixed portion 21 mounted on the base 3;
A moving unit 22 connected to the X-axis stage 19; The moving unit 22 is connected to a controller (not shown), and is moved in the Z-axis direction under the control of the controller. As the moving unit 22 moves, the X-axis stage 19, the Y-axis stage 18, the rotary stage 17, The stage 14, the support 11, and the electron gun 2 supported thereby move in the Z-axis direction.

The position data of the electron gun 2 measured by the position measuring mechanism 30 is supplied to a controller for controlling the operation of moving the support stage 10. The controller controls the movement of each stage constituting the support stage 10 based on the position data of the electron gun 2 supplied from the position measuring mechanism 30.

The position measuring mechanism 30 includes, for example, a laser displacement meter 31 as means for measuring the external position of the electron gun 2 supported on the support stage 10. Laser displacement meter 31
Measures the external position of the electron gun 2 by irradiating the electron gun 2 supported by the support stage 10 with laser light and detecting the light reflected by the electron gun 2.

More specifically, the position measuring mechanism 30 irradiates the electron gun 2 with laser light by the laser displacement meter 31 while rotating the electron gun 2 by driving the rotary stage 17 of the support stage 10. , And the reflected light is detected. Then, the position measuring mechanism 30 calculates the rotation angle of the rotation stage 17,
Based on the current positions of the X-axis stage 19 and the Y-axis stage 18 and the measured outer position of the electron gun 2 measured by the laser displacement meter 31, the center of the electron gun 2 is moved with respect to a predetermined inspection position in the X-axis direction. And the positional relationship in the Y-axis direction is calculated in μm order.

The position measuring mechanism 30 measures the outer positions of the electron gun 2 supported on the support stage 10 at two or more positions in the Z-axis direction by the laser displacement meter 31, and uses the measured values of the outer positions of the electron gun 2 based on the measured values. 2 is calculated.

The position data of the electron gun 2 measured by the position measuring mechanism 30 is supplied to the controller. Based on the position data, the controller uses the support stage 1
The respective stages 0 are driven to position the electron gun 2 at a predetermined inspection position.

An electron gun position shift inspection apparatus 1 according to the present invention.
Drives the support stage 10 based on the position data measured by the position measuring mechanism 30 to position the electron gun 2 at a predetermined position as described above.
The positioning of the electron gun 2 can be performed accurately and easily.

On the axis of the support stage 10,
A displacement detection mechanism 40 is disposed at a position facing the second mounting surface 12a.

The position shift detecting mechanism 40 detects the position shift between the grids of the electron gun 2 using the principle of a polarizing microscope, and as shown in FIG. 2, a light source 41 for emitting non-polarized light. And a first polarizing plate 42 that transmits unpolarized light emitted from the light source 41 and changes it to linearly polarized light.
A half mirror 43 that transmits a part of the linearly polarized light transmitted through the first polarizing plate 42 and reflects the other part, and an objective lens that condenses the light reflected by the half mirror 43 on the electron gun 2 44, a second polarizing plate 45 disposed on the optical path of the reflected light reflected by the electron gun 2 and transmitted through the objective lens 44 and the half mirror 43, and reflected light transmitted through the second polarizing plate 45 as an image. And a CCD camera 46 that captures the images.

The light source 41 emits unpolarized light in a direction orthogonal to the Z axis. The position shift detecting mechanism 40 is provided with the light source 4.
Although it may be configured such that the unpolarized light from No. 1 is directly incident on the first polarizing plate 42, as shown in FIG.
Using an optical transmission means 47 such as an optical fiber, unpolarized light from the light source 41 is transmitted through the optical transmission means 47 to the first polarizing plate 4.
2 may be incident. Thus, the light source 4
When the non-polarized light from No. 1 is incident on the first polarizing plate 42 via the light transmission means 47, the installation position of the light source 41 can be freely selected, and the space can be saved. The above is advantageous.

The first polarizing plate 42 has a polarization axis in a certain direction, and is disposed on the optical path of unpolarized light emitted from the light source 41. Then, the first polarizing plate 42 is connected to the light source 41.
The light emitted from is transmitted and changed to linearly polarized light.

The half mirror 43 is disposed so as to be inclined at an inclination angle of 45 degrees with respect to the Z axis on the optical path of the linearly polarized light transmitted through the first polarizing plate 42. The half mirror 43 transmits a part of the linearly polarized light, reflects the other part, and bends in a direction along the Z axis.

The objective lens 44 includes a plurality of lenses 44
a, 44b and 44c are combined and arranged on the optical path of the linearly polarized light reflected by the half mirror 43. Then, the objective lens 44 includes the half mirror 4
The linearly-polarized light reflected by 3 is condensed and emitted to the electron gun 2 supported on the support stage 10.

The second polarizing plate 45 has a polarizing axis in a direction different from the polarizing axis of the first polarizing plate 42, and
The electron gun 2, the objective lens 44, and the half mirror 43, which are supported by the camera, are arranged on the same axis. The second polarizing plate 45 blocks part of the reflected light from the electron gun 2 transmitted through the objective lens 44 and the half mirror 43 according to the polarization state, and transmits the other part.

The CCD camera 46 is disposed at a position facing the second polarizing plate 45, and takes in the reflected light from the electron gun 2 transmitted through the second polarizing plate 45 as an image. . As shown in FIG. 1, an image display monitor 49 is connected to the CCD camera 46 via a monitor controller 48, and an image captured by the CCD camera 46 is displayed on the image display monitor 49. ing.

The image display monitor 49 has a CCD camera 4
In addition to the image captured by 6, a micro scale for position measurement is displayed. Therefore, by observing the image captured by the CCD camera 46 on the basis of the micro-scale, it is possible to measure the displacement between the grids of the electron gun 2.

Here, the position shift inspection apparatus 1 for the electron gun
A method for inspecting a position shift between grids of an electron gun using the method will be described. Here, an example will be described in which the displacement between the first grid and the second grid of the electron gun 2 is detected. Of course, it can be detected.

First, the electron gun 2 is supported by the support portion 11 of the support stage 10 with the cathode side in contact with the mounting surface 12a. Then, the position of the electron gun 2 on the support stage 10 is measured by the position measuring mechanism 30, and when the electron gun 2 is not at the predetermined inspection position, that is, the center of the electron beam transmitting hole of the first grid is shifted by the position shift detecting mechanism 40. Is not located on the optical axis of the electron gun 2 under the control of the controller,
Is corrected.

Next, unpolarized light is emitted from the light source 41 of the displacement detection mechanism 40. The unpolarized light emitted from the light source 41 is converted to linearly polarized light by transmitting through the first polarizing plate 42. A part of the linearly polarized light is transmitted by the half mirror 43 and the other part is reflected.

The linearly polarized light reflected by the half mirror 43 is condensed by the objective lens 44, enters the electron gun 2, and strikes the surfaces of the first and second grids and the electron beam emission surface of the cathode. Irradiated.

By the way, the first grid and the second grid each have a flat metal surface formed with an electron beam transmitting hole formed by punching, and the vicinity of the edge of the electron beam transmitting hole is in the punching direction. It is in an inclined state. Therefore, the first grid and the second grid
The linearly polarized light applied to the surface of the grid is strongly reflected at locations other than near the edges of the electron beam transmission holes, whereas the amount of reflected light is very small near the edges.

The linearly polarized light applied to the grid surface is reflected on the grid surface while maintaining the linearly polarized state because the grid surface is a flat metal surface.

Further, since the electron beam emission surface of the cathode is a fine uneven surface of oxide, the electron beam emission surface of the cathode is irradiated through the electron beam transmission holes of the second grid and the first grid. The linearly polarized light repeats refraction and reflection on the electron beam emission surface of the cathode, and is reflected in a state where the polarization state is broken.

The light reflected by the grid surface and the electron beam emission surface of the cathode passes through the objective lens 44 again and is irradiated on the half mirror 43. The half mirror 43 transmits a part of the light reflected from the grid surface and the electron beam emission surface of the cathode, and reflects the other part.

The light reflected by the grid surface and the electron beam emission surface of the cathode transmitted by the half mirror 43 is incident on the second polarizing plate 45. At this time, the reflected light from the grid surface and the electron beam emission surface of the cathode is:
A part is blocked by the second polarizing plate 45 according to the polarization state, and the other part is transmitted through the second polarizing plate 45.

For example, when the second polarizing plate 45 is arranged so that its polarization axis is substantially 90 degrees (crossed Nicols) with respect to the polarization axis of the first polarizing plate 42, the reflected light from the grid surface is Since the linearly polarized state is maintained by the first polarizing plate 42, most of the linearly polarized light is kept in the second polarizing plate 45.
And the amount of reflected light transmitted through the second polarizing plate 45 is 1/400 of the amount of light emitted from the light source 41.
Degree. That is, the luminous flux after passing through the half mirror 43 and the second polarizing plate 45 is about 1/200 or less of the luminance of the light reflected from the grid surface.

On the other hand, the reflected light from the electron beam emission surface of the cathode is random because the polarization state is broken, so that the ratio of the light blocked by the second polarizing plate 45 is reduced and the light is emitted from the light source 41. About 1/16 or less of the amount of light passes through the second polarizing plate 45. That is, the half mirror 4
3 and the luminous flux after passing through the second polarizing plate 45 is 1/1 of the luminance of the reflected light from the electron beam emission surface of the cathode.
It is about 4 or less.

The reflected light from the grid surface and the electron beam emission surface of the cathode transmitted through the second polarizing plate 45 is captured by the CCD camera 46 via the objective lens 46 and displayed on the image display monitor 49. At this time, by performing the focus adjustment while moving the Z-axis stage 20 of the support stage 10, the edges of the electron beam transmission holes of the first grid and the edges of the electron beam transmission holes of the second grid become first and second. The image is displayed on the image display monitor 49 as a line due to the difference in the amount of reflected light from the surface of the two grids and the amount of reflected light from the electron beam emission surface of the cathode.

Then, the edges of the electron beam transmitting holes of the first grid and the edges of the electron beam transmitting holes of the second grid, which are displayed as lines on the image display monitor 49, are measured on the basis of a micro scale, whereby the first grid is measured. And the second
The displacement between the grids is measured.

Here, the second light reflected by the surface of the grid
The difference between the amount of reflected light transmitted through the polarizing plate 45 and the amount of reflected light reflected on the electron beam emission surface of the cathode and transmitted through the second polarizing plate 45 will be described with reference to FIGS. I do. Here, the amount of light reflected on the surface of the grid and the amount of light reflected on the electron beam emission surface of the cathode are reduced by passing through the second polarizing plate 45, respectively. To clarify
For convenience, the description will be made assuming that the reflectivity at the surface of the grid and the electron beam emission surface of the cathode is 100%. In particular, since the electron beam emission surface of the cathode is uneven as described above, diffuse reflection occurs. For convenience, it is assumed that reflection without diffusion occurs. Here, for convenience, it is assumed that there is no half mirror 43 shown in FIG. 2, and the reflectance and transmittance of the half mirror 43 are ignored.

The unpolarized light emitted from the light source 41 and directed to the grid surface is, as shown in FIG.
The light is converted into linearly polarized light by 2 and is irradiated on the grid surface. At this time, in the non-polarized light emitted from the light source 41, almost all of the light of the polarization component orthogonal to the polarization axis of the first polarizing plate 42 is absorbed by the first polarizing plate 42, and the remaining 50% (Light having a polarization component in the same direction as the polarization axis of the first polarizing plate 42) passes through the first polarizing plate 42. That is, about 50% of the light emitted from the light source 41 becomes linearly polarized light and passes through the first polarizing plate 42.

The light transmitted through the first polarizing plate 42 and reflected on the grid surface is converted into the second polarizing plate while maintaining the state of linearly polarized light because the grid surface is a flat metal surface. Head to 45.

When the second polarizing plate 45 is arranged such that its polarization axis is substantially 90 degrees (crossed Nicols) with respect to the polarization axis of the first polarizing plate 42, usually, Since the extinction ratio is 1/100 or less, 1% or less of the light passes through the second polarizing plate 45.

On the other hand, the unpolarized light emitted from the light source 41 and directed to the electron beam emission surface of the cathode is converted into linearly polarized light by the first polarizing plate 42 as shown in FIG.
Irradiation is performed on the electron beam emission surface of the cathode. At this time,
The unpolarized light emitted from the light source 41 is
Almost all of the light of the polarization component orthogonal to the second polarization axis is absorbed by the first polarizing plate 42, and the remaining 50% of the light (light of the polarization component in the same direction as the polarization axis of the first polarization plate 32) ) Transmits through the first polarizing plate 42. That is, the light source 41
Approximately 50% of the light emitted from the light becomes linearly polarized light and passes through the first polarizing plate 42.

The light transmitted through the first polarizing plate 42 and reflected on the electron beam emission surface of the cathode repeats refraction and reflection on the electron beam emission surface, which is a fine uneven surface of the oxide. The light is directed to the second polarizing plate 45 in a state where the polarization state is broken. Here, as assumed, the reflection on the electron beam emission surface of the cathode is assumed to have no diffusion or absorption.
To the polarizing plate 45.

As for the reflected light from the electron beam emitting surface of the cathode toward the second polarizing plate 45, almost all of the light of the polarization component orthogonal to the polarization axis of the second polarizing plate 45 is formed. And the remaining 50% of the light (light having a polarization component in the same direction as the polarization axis of the second polarizing plate 45), that is, about 25% of the light emitted from the light source 41 is reflected by the second polarizing plate 45. To Penetrate.

As described above, it has been described that the amount of reflected light reflected on the surface of the grid and the amount of reflected light reflected on the electron beam emission surface of the cathode are different by using polarized light. In actual observations, even if the light has the polarization in the same direction as the polarization axis of the polarizing plate, it will be absorbed by the polarizing plate, or how much light having the polarization in the direction perpendicular to the polarization axis of the polarizing plate will be absorbed. Depending on the performance of the polarizing plate, such as the extinction ratio of the polarizing plate, the light amount ratio described above and shown in FIGS. 3 and 4 varies.

In the above description, the case where there is no half mirror has been described for the sake of convenience. However, in actual illumination and observation, the amount of light is reduced to half by performing through the half mirror. Also, depending on the performance of the half mirror,
The amount of light transmitted or reflected by the half mirror changes.
Further, the present invention can be implemented by using a polarization beam splitter or the like instead of the half mirror. However, even when the polarization beam splitter is used instead of the half mirror, the light amount changes.

In the above description, the reflectance on the surface of the grid and on the electron beam emission surface of the cathode is assumed to be 100% for convenience. However, in reality, each of these reflectances has a certain value. Since the surface of the grid is a metal surface, most of the incident light is reflected without being scattered. Thus, the reflectivity of the grid surface is high, sometimes as high as 90% or more. On the other hand, the surface of the electron beam emission surface of the cathode is uneven, and the reflected light is not a simple reflection but a mixture of reflection and scattering having a certain distribution in the light emission direction. The reflected light mixed with the reflection and the scattering also has a different distribution in the emission direction depending on the incident direction of the light. Therefore, the reflectance determined from the amount of light to be illuminated and the amount of light observed also depends on the state of the electron beam emission surface of the cathode, and further depends on the optical performance such as the numerical aperture of the objective lens.

In the above description, for convenience, the electron beam emission surface of the cathode is assumed to be a 100% reflective surface. However, the electron beam emission surface of the cathode is assumed to be a perfect diffuse reflection surface which can be substituted by magnesium oxide. Assuming that it is possible to estimate the light quantity ratio when the reflected light mainly reflecting the scattering rather than the reflection is observed. Also in this case, it is necessary to take into account the optical characteristics of the microscope such as the numerical aperture of the objective lens of the microscope.

Thus, the polarizing plate, the half mirror,
By appropriately adjusting the performance of each optical element of the optical system such as an objective lens, the reflected light reflected on the grid surface and the reflected light reflected on the electron beam emission surface of the cathode are different depending on the polarization state. The separated and observed image can be made clearer.

An electron gun position shift inspection apparatus 1 according to the present invention.
As described above, by using a polarizing plate,
The amount of linearly polarized light reflected on the surface of the grid is greatly reduced, and the electron beam emission surface of the cathode is relatively brightened. Since the brightness contrast is improved, the edge of the beam transmission hole can be clearly observed, and the displacement between grids of the electron gun can be accurately detected.

That is, when unpolarized light is directly irradiated onto the surface 51a of the grid 51 and the electron beam emission surface 52a of the cathode 52 without using a polarizing plate, and the reflected light is observed, as shown in FIG. The amount of light reflected on the grid surface 51a other than the portion 55 near the edge 54 of the electron beam transmission hole 53 is very large, whereas the vicinity 55 of the edge 54 of the electron beam transmission hole 53 and the cathode 52 The amount of light reflected by the electron beam emission surface 52a of the first and second electron beams is reduced. Therefore, when these are observed, as shown in FIG. 6, the light reflected at the vicinity 55 of the edge 54 of the electron beam transmission hole 53 and the light reflected at the electron beam emission surface 52a of the cathode 52 are darkly mixed. As a result, the edge 54 of the electron beam transmission hole 53 cannot be clearly discriminated, so that a positional displacement between the grids 51 of the electron gun cannot be accurately detected.

On the other hand, when the reflected light from the surface 51a of the grid 51 and the electron beam emission surface 52a of the cathode 52 is observed using the electron gun displacement inspection apparatus 1 according to the present invention, FIG. As shown in FIG. 8, the amount of light reflected on the surface 51a of the grid 51 is greatly reduced, and the amount of light reflected on the electron beam emission surface 52a of the cathode 52 is relatively large. As shown, the edge 54 of the beam transmission hole 53 can be clearly distinguished, and the displacement between the grids 51 of the electron gun can be accurately detected. 5 and 7, the difference in the amount of light reflected from the surface 51a of the grid 51 and the electron beam emission surface 52a of the cathode 52 is indicated by the difference in the thickness of the arrow in the figure.

Further, in the electron gun misalignment inspection apparatus 1 according to the present invention, the support stage 10 supports the electron gun 2 so that its central axis is along the Z-axis direction, and the misalignment detection mechanism 40
Illuminates the electron gun 2 supported by the support stage 10 with illumination light in a direction along the central axis, so that the utilization efficiency of the illumination light is improved, and the surface of the grid and the electron emission surface of the cathode are improved. Can be illuminated uniformly and brightly. Therefore, according to the position shift inspection apparatus 1 for the electron gun, it is possible to observe the edge portion of the electron beam transmission hole at a high magnification, and it is possible to accurately detect the position shift between the grids.

Further, the position shift inspection apparatus 1 for the electron gun according to the present invention drives the support stage 10 based on the position data measured by the position measurement mechanism 30 to position the electron gun 2 at a predetermined position. So the electron gun 2
Can be accurately and simply positioned at the measurement position.

In the above description, the displacement detection mechanism 40 has the light source 41 for emitting unpolarized light and the first polarizing plate 42, and converts the unpolarized light emitted from the light source 41 to the first polarized light. Although the electron gun misalignment inspection apparatus 1 in which linearly polarized light is emitted to the electron gun by passing through the plate 42 has been described, the electron gun misalignment inspection apparatus according to the present invention is limited to this example. Instead, for example, the light source may emit linearly polarized light such as a laser, and the light may be directly applied to the electron gun without passing through the polarizing plate.

Further, the position shift inspection apparatus for an electron gun according to the present invention only illuminates the electron gun with linearly polarized light and distinguishes between the linearly polarized reflected light and the reflected light in which the deflection is in a random state. Instead, light whose deflection state is adjusted such as circular deflection can be used. For example, a quarter-wave plate is provided between the objective lens of the displacement detection mechanism and the electron gun supported on the support stage, and linearly polarized light is
The light is converted into circularly polarized light by transmitting through a wave plate, and is irradiated on an electron gun. The circularly polarized light reflected by the electron gun is again converted into linearly polarized light by transmitting through a quarter wave plate. This reflected light may be observed.

[0085]

The electron gun position shift inspection apparatus according to the present invention irradiates the electron gun with linearly polarized light, and observes the reflected light reflected by the electron gun through a polarizing means. The amount of reflected light from the grid surface of the gun is reduced so that the reflected light from the electron beam emission surface of the cathode becomes relatively bright. Therefore, according to the electron gun position shift inspection apparatus, the brightness contrast between the vicinity of the edge of the electron beam transmission hole provided in the grid and the electron beam emission surface of the cathode is improved, and thus the electron beam transmission hole is improved. The edge can be clearly distinguished, and the displacement of the electron gun can be accurately detected.

Further, in the electron gun position deviation inspection apparatus according to the present invention, the position of the electron gun on the electron gun supporting means is measured by the position measuring means, and the electron gun is driven by the driving means based on the position data of the electron gun. By driving the support means, the electron gun is positioned at the predetermined inspection position, so that the positioning of the electron gun at the inspection position can be performed accurately and easily.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of an electron gun position shift inspection apparatus according to the present invention.

FIG. 2 is a schematic view showing a displacement detection mechanism of the displacement detection device for the electron gun.

FIG. 3 is a diagram illustrating a polarization state and a light amount of light reflected on a grid surface.

FIG. 4 is a diagram illustrating a polarization state and a light amount of light reflected on an electron beam emission surface of a cathode.

FIG. 5 is a cross-sectional view illustrating a difference in light amount between a case where non-polarized light is applied to the grid surface and the electron beam emission surface of the cathode, and the reflected light is observed as it is.

FIG. 6 is a plan view showing an observation image in a case where non-polarized light is applied to the grid surface and the electron beam emission surface of the cathode, and the reflected light is observed as it is.

FIG. 7 is a cross-sectional view illustrating a difference in light amount between a case where linearly polarized light is applied to a grid surface and an electron beam emission surface of a cathode, and reflected light is observed through a polarizing plate.

FIG. 8 is a plan view showing an observation image when linearly polarized light is applied to the surface of the grid and the electron beam emission surface of the cathode, and the reflected light is observed through a polarizing plate.

FIG. 9 is a cross-sectional view showing a state in which a displacement has occurred between grids of the electron gun.

FIG. 10 is a configuration diagram showing a conventional electron gun displacement detection apparatus.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 electron gun position shift inspection device, 2 electron gun, 10 support stage, 30 position measurement mechanism, 31 laser displacement meter, 40 position shift detection mechanism, 41 light source, 42 first polarizing plate, 44 objective lens, 45 second Polarizing plate, 46
CCD camera

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Ichida, Inventor 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Joh Watanabe 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo No. F-term (reference) in Sony Corporation 5C012 AA02 BE03

Claims (6)

[Claims] An electron gun supporting means for movably supporting an electron gun to be inspected; a position measuring means for measuring a position of the electron gun on the electron gun supporting means; Driving means for driving the electron gun support means based on the position data of the electron gun to move the electron gun to a predetermined inspection position; and a displacement between grids of the electron gun at the inspection position. A position deviation inspection unit for inspecting, the position deviation inspection unit irradiates the electron gun with linearly polarized light, and observes reflected light reflected by the electron gun through a polarization unit. An electron gun misalignment inspection apparatus for inspecting misalignment between grids of the electron gun. 2. The method according to claim 1, wherein the position measuring means irradiates the electron gun with a laser beam, and detects a reflected light of the electron gun to measure an outer position of the electron gun on the electron gun supporting means. The apparatus according to claim 1, further comprising: 3. The electron gun supporting means comprises a mechanism for moving the electron gun in two directions substantially parallel to each other and substantially perpendicular to a surface on which the electron gun is mounted. 3. An electron gun position deviation inspection apparatus according to claim 1. 4. The electron gun according to claim 1, wherein said electron gun supporting means includes a mechanism for moving said electron gun in a direction substantially orthogonal to a surface on which said electron gun is mounted. Misalignment inspection equipment. 5. The electron gun according to claim 1, wherein said electron gun supporting means includes a mechanism for rotating a surface on which said electron gun is mounted, about an axis substantially orthogonal to said surface. Gun position shift inspection device. 6. An apparatus according to claim 1, wherein said electron gun supporting means includes a mechanism for inclining a surface on which said electron gun is mounted.