JPH1144521A - Shadow mask inspecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable fine holes over an entire shadow mask face to be inspected always correctly by rotating a mask face of the shadow mask relatively around an axis core at the right angle to a light axis direction of a line sensor camera by a rotating mechanism. SOLUTION: A rotary table 3 driven by a rotary table driving motor 4 rotates a shadow mask 1 and a holder 2. A line sensor camera 5 is oppositely placed to 7 protruding face side of a mask face 1a of the shadow mask 1 for observing the mask face 1a in a linear field of view. A focus table 6 is moved by a focus table driving motor 7 toward a light axis A of the line sensor camera 5 in order to align a focus of the line sensor camera 5. Since the mask face 1a of the shadow mask 1 is rotated along an axis core at the right angle to the light axis A direction of the line sensor camera 5 by the rotary table 3, fine holes on the mask face can be observed free from influence of distortion caused by a molded shape of the shadow mask 1 in the light axis A direction of the line sensor 5 over the entire mask face 1a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask inspection apparatus for inspecting a myriad of fine holes formed on a mask surface of a shadow mask having a three-dimensional surface shape with high accuracy and high speed.

[0002]

2. Description of the Related Art An infinite number of fine holes are provided on a mask surface of a shadow mask such as a CRT.

[0003] Various automatic inspection apparatuses have been developed to inspect defects such as clogging of fine holes and abnormal diameters of holes with high accuracy and high speed. FIG. 5 is a schematic diagram showing a schematic configuration of an example of such a conventional shadow mask inspection apparatus.

As shown in FIG. 5, a conventional shadow mask inspection apparatus includes a holder 2 for fixing a formed shadow mask 1, a line sensor camera 5 for observing a mask surface 1a of the shadow mask 1 in a linear visual field. A focus table 6 for adjusting the focus of the line sensor camera 5, a focus table driving motor 7 for moving the focus table 6 in the optical axis A direction of the line sensor camera 5, and an operation of the focus table driving motor 7. A controller 8 is provided.

[0005] A conventional shadow mask inspection apparatus operates as follows. First, the shadow mask 1 is fixed to the holder 2 such that the mask surface 1a faces the line sensor camera 5. Next, the focus table drive motor 7 is driven by a command from the controller 8 to move the focus table in the direction of the optical axis A, whereby the focus of the line sensor camera 5 is adjusted. And
The line sensor camera 5 observes the mask surface 1a of the shadow mask 1. Based on this observation result, an inspection of the myriad of fine holes provided on the mask surface 1a is performed.

[0006]

In the above-mentioned conventional configuration,
Since the mask surface 1a of the formed shadow mask 1 has a three-dimensional surface shape, the line sensor camera 5
The optical path length up to the center varies greatly between the center and both ends, and there is a part in the field of view of the line sensor camera 5 that is out of focus. Further, even in the focused portion, the fine hole to be inspected has a shape distorted when viewed from the optical axis A direction of the line sensor camera 5 on the mask surface 1a having the three-dimensional surface shape. Therefore, it may not be possible to accurately inspect the shape of the fine hole over the entire mask surface 1a of the formed shadow mask 1.

The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a shadow mask inspection method capable of always accurately inspecting fine holes over the entire mask surface of a shadow mask. It is to provide a device.

[0008]

In order to achieve the above object, the present invention provides a line sensor camera for observing a mask surface of a molded shadow mask, and a method for moving the line sensor camera in the direction of its optical axis. In a shadow mask inspection apparatus provided with a focus mechanism for adjusting the rotation angle, a rotation mechanism for relatively rotating the mask surface around an axis perpendicular to the optical axis direction of the line sensor camera, and the rotation mechanism and the focus mechanism operate in synchronization. In this way, a controller for controlling both mechanisms is provided. In such a configuration, since the rotating mechanism rotates the mask surface of the shadow mask relatively around an axis perpendicular to the optical axis direction of the line sensor camera, the optical axis direction of the line sensor camera extends over the entire mask surface. Can be observed. For this reason, the fine holes on the mask surface can be inspected only for the original defect without being affected by the distortion caused by the molded shape of the shadow mask.

Further, since the controller controls the rotation mechanism and the focus mechanism to operate in synchronization, the rotation mechanism rotates the mask surface, and the optical path length from the mask surface to the line sensor camera changes. Also, since the focusing mechanism simultaneously performs the focusing operation in accordance with the change in the optical path length, the inspection can be performed in a state where the entire surface of the mask surface is always in focus.

More specifically, the controller calculates the operation speed data of the rotation mechanism and the focus mechanism based on the separately input shape of the mask surface, and stores the calculated operation speed data. And a transmitter for simultaneously transmitting the stored operation speed data to the holder rotation drive mechanism and the focus mechanism at predetermined time intervals.

As a result, the fine holes can be always accurately inspected over the entire mask surface of the shadow mask.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The following embodiments are examples in which the present invention is embodied, and do not limit the technical scope of the present invention.

FIG. 1 is a schematic diagram showing a schematic configuration of a shadow mask inspection apparatus according to the present embodiment. As shown in FIG. 1, a shadow mask inspection apparatus according to the present embodiment (hereinafter, referred to as “this apparatus”) rotates a holder 2 for fixing a formed shadow mask 1 and rotates the shadow mask 1 and the holder 2. Rotary table 3 and rotary table 3
, A rotary table driving motor 4 for driving the mask, a line sensor camera 5 disposed opposite to the convex surface of the mask surface 1a of the shadow mask 1 for observing the mask surface 1a in a line-shaped visual field, and a focus of the line sensor camera 5 A focus table 6, a focus table driving motor 7 for driving the focus table 6 so that the focus table 6 moves in the direction of the optical axis A of the line sensor camera 5, a rotary table driving motor 4, A controller 8 for controlling the table driving motor 7 to operate in synchronization is provided. Of these, the rotary table 3 and the rotary table driving motor 4 constitute a rotating mechanism, and the focus table 6 and the focus table driving motor 7 constitute a focusing mechanism. Further, the direction of the rotation axis B of the turntable 3 is a direction perpendicular to the direction of the optical axis A of the line sensor camera 5, but here, for convenience of explanation, is the vertical direction in the figure. It goes without saying that the longitudinal direction of the line sensor of the line sensor camera 5 is in the vertical direction.

FIG. 2 is a system configuration diagram of the controller 8. As shown in FIG. 1 and FIG.
Is a ROM 11 storing a program for calculating the moving speed of the rotary table 3 and the focus table 6 from the separately input shape of the mask surface 1a of the shadow mask 1.
And a CPU 10 for executing the program,
RAM 12 for storing speed data calculated by 0
A register 13 included in the CPU 10 for storing speed data from the RAM 12 at regular time intervals, a pulse transmitter 14 for simultaneously transmitting a pulse signal from the CPU 10 to the rotary table driving motor 4 and the focus table driving motor 7, An address data bus 15 for transmitting and receiving data and signals. Of these, CPU 10 and R
The OM 11 forms an operation unit, and the RAM 12 and the register 13
Constitute a storage unit, and the pulse transmitter 14 constitutes a transmission unit.

FIG. 3 is a flowchart showing a processing procedure according to a program stored in the ROM 11, and the operation of the present apparatus is performed by executing this program. Hereinafter, the operation of the present apparatus will be mainly described with reference to FIG. That is, as shown in FIG. 3, first, the shape and size of the mask surface 1a of the shadow mask 1, ie, the work size, are set by an appropriate input device (not shown) (step S1). Next, the rotary table 3 at the time t _i
The velocity data V [theta] _i, the velocity data Vkai _i of the focus table 6 respectively calculates (step S2).

FIG. 4 is a diagram showing the relationship between R and R stored in advance.
An example of calculation of speed data by a program in the OM 11 is shown. In FIG. 4A, the time t ₁ ,..., T _i , t _{i + 1} ,.
The relationship 16 of θ _i , Vθ _{i + 1} ,... is described, and this shows the change in the rotation speed when scanning the entire mask surface 1 a of the shadow mask 1. FIG.
In (b), the time t ₁ of the focus table 6,
..., t _i , t _{i + 1} , ... and velocity data 0, ..., V ， _i , V
関係 Describes the relationship 17 of _{i + 1} ,.
Represents the change in the speed of the focus table 6 associated with the change in the rotation speed of the focus table 6. Thereby, the rotary table 3
The focus of the line sensor camera 5 can be adjusted in accordance with the change in the optical path length from the mask surface 1a to the line sensor camera 5 due to the rotation of Further, FIGS. 4A and 4B show a time interval Δt (= t _{i + 1} −t _i ) for setting each speed.
Are described respectively.

From the velocity data Vθ _i , Vχ _i calculated by the above program, the velocity data Vθ _i , Vχ _i are stored in the RAM at every time interval Δt, as shown in FIG. 3 again.
It is set to 12 (step S3).

Next, the speed data Vθ _i , Vχ _i are stored in RA
Read from M12, to set the velocity data V [theta] _i, the register 13 Vkai _i as a pulse signal of a fixed time interval (step S4). This pulse signal is simultaneously transmitted from the pulse transmitter 14 to the rotary table driving motor 4 and the focus table driving motor 7, thereby simultaneously rotating the rotary table 3 and the focus table 6 at the time interval △.
It is moved by t (step S5).

Steps S4 and S5 are repeated until the speed data reaches the end (step S6).

As described above, according to the present apparatus, the rotary table 3 driven by the rotary table driving motor 4
Since the mask surface 1a of the shadow mask 1 is rotated around an axis perpendicular to the direction of the optical axis A of the line sensor camera 5, the line sensor camera 5 extends over the entire mask surface 1a.
Can be observed in the direction of the optical axis A. For this reason, the fine holes in the mask surface 1a can be inspected only for the original defect without being affected by the distortion caused by the shape of the shadow mask 1.

Further, since the controller 8 controls the rotary table driving motor 4 and the focus table driving motor 7 to operate synchronously, the rotary table 3 rotates the mask surface 1a, and Even if the optical path length from the surface 1a to the line sensor camera 5 changes, the focus table 6 driven by the focus table driving motor 7 simultaneously performs a focus operation according to the change in the optical path length. Inspection can be performed in a state where the focus is always adjusted over the entire surface of the device.

As a result, the mask surface 1 of the shadow mask 1
The microholes can always be inspected accurately over the entire surface of a.

In the above-described embodiment, the line sensor camera 5 is provided so as to face the convex surface of the mask surface 1a of the shadow mask 1. On the contrary, the line sensor camera 5 faces the concave surface of the mask surface 1a. May be deployed. Further, in the above embodiment, the direction of the rotation axis of the mask surface 1a of the shadow mask 1 is set in the up-down direction, but any direction as long as it is perpendicular to the optical axis A of the line sensor camera 5 is set. Is also good. In the above embodiment, the mask surface 1a of the shadow mask 1 is rotated.
May be fixed, and the line sensor camera 5 may be rotated therearound. In short, what is necessary is just to rotate the mask surface 1a relatively to the line sensor camera 5,
In this case, both the rotation mechanism and the focus mechanism are provided on the line sensor camera 5 side.

[0024]

As is apparent from the above description, according to the present invention, the fine holes on the mask surface of the shadow mask are inspected for only the original defects without being affected by the distortion caused by the shape of the shadow mask. it can. In addition, the inspection can be performed in a state where the entire mask surface of the shadow mask is always in focus. As a result, the fine holes can be always accurately inspected over the entire mask surface of the shadow mask.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a shadow mask inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a system configuration diagram of a controller of the present apparatus.

FIG. 3 is a flowchart showing an operation procedure according to a program in a controller of the apparatus.

FIG. 4 is an explanatory diagram showing an example of speed data stored in a ROM of the apparatus.

FIG. 5 is a schematic diagram showing a schematic configuration of a shadow mask inspection apparatus according to a conventional example.

[Explanation of symbols]

Reference Signs List 1 shadow mask 2 holder 3 rotary table (rotary mechanism) 4 rotary table drive motor (rotary mechanism) 5 line sensor camera 6 focus table (focus mechanism) 7 focus table drive motor (focus mechanism) 8 controller 10 CPU (calculation unit) 11) ROM (arithmetic unit) 12 RAM (storage unit) 13 register (storage unit) 14 pulse oscillator (oscillation unit) 15 address data bus

Claims (2)

[Claims] 1. A shadow mask inspection apparatus comprising: a line sensor camera for observing a mask surface of a shaped shadow mask; and a focus mechanism for moving the line sensor camera in an optical axis direction to focus. A rotation mechanism for relatively rotating the optical axis about an axis perpendicular to the optical axis direction of the line sensor camera, and a controller for controlling both mechanisms so that the rotation mechanism and the focus mechanism operate in synchronization. Shadow mask inspection equipment. 2. An arithmetic unit for calculating operation speed data of a rotation mechanism and a focus mechanism based on a separately input shape of the mask surface, and a storage unit for storing the calculated operation speed data. 2. The shadow mask inspection apparatus according to claim 1, further comprising: a transmission unit for simultaneously transmitting the stored operation speed data to the holder rotation drive mechanism and the focus mechanism at predetermined time intervals.