JP2004150855A - Light intensity correcting method and light intensity corrector for measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light intensity correcting method and a light intensity corrector for easily coping with secular change of an illumination light source and change or variation in illumination light intensity due to instrumental error. <P>SOLUTION: A reference value for illumination light intensity is obtained by using an image measuring instrument serving as a reference. This reference value is stored in an image measuring instrument other than the measuring instrument serving as the reference, and illumination light intensity is corrected by using this reference value when using an image measuring instrument other than the measuring instrument serving as the reference. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light amount correction method and a light amount correction device for a measuring instrument.
[0002]
[Prior art]
[0003]
[Patent Document]
JP-A-9-189522
2. Description of the Related Art Conventionally, in an image measuring device, an illumination light amount is adjusted by controlling a light amount adjustment unit using a computer based on an image signal output from a camera in accordance with the light amount of an image formed by an optical system.
[0005]
[Problems to be solved by the invention]
However, when the image measuring device is used for a long period of time, the light amount gradually decreases due to the deterioration of the lamp and the like, and when a measurement program (a measurement procedure of light amount, position, etc.) stored in the computer is executed, a desired value is obtained. A problem arises in that the amount of illumination light cannot be obtained, and the measurement accuracy deteriorates or measurement cannot be performed.
[0006]
Further, even if lamps of the same standard are used, it is not always possible to obtain the same amount of illumination light, and since there is a variation between measuring devices, the same problem occurs when an image measuring device is used for a long period of time. .
[0007]
In the above case, it is necessary to modify the measurement program (change the illumination light amount information), which complicates the operation.
[0008]
The present invention has been made in view of such circumstances, and a problem thereof is a light amount correction method and a light amount correction method for a measuring device that can easily cope with changes and variations in the amount of illumination due to aging of the illumination light source and machine differences. It is to provide a device.
[0009]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 obtains a reference value of the illumination light amount using a reference measuring device, and stores the reference value in a measuring device other than the reference measuring device, When a measuring instrument other than the reference measuring instrument is used, the illumination light amount is corrected using the reference value.
[0010]
According to a second aspect of the present invention, there is provided a storage unit for storing a reference value of an illumination light amount calculated using a reference measuring device, a detection unit for detecting an illumination light amount, and an illumination light amount detected by the detection unit. Correction value calculation means for calculating a correction value based on the reference value stored in the storage means and the reference value stored in the storage means, and light amount correction means for correcting the illumination light amount based on the correction value. Features.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0012]
FIG. 1 is a block diagram of a light quantity correction device for an image measuring device according to an embodiment of the present invention.
[0013]
This image measuring machine (measuring machine) includes a stage 3, a lamp 4, a light amount correcting section (light amount correcting means) 5, an optical system 6, a CCD camera 7, a base 8, and a computer 10. I have. The light quantity correction unit 5 and the computer 10 constitute a light quantity correction device.
[0014]
The lamp 4, the object 2, the optical system 6, and the CCD camera 7 are arranged on the same optical axis.
[0015]
On the stage 3, for example, an object 2 to be measured such as a semiconductor or a connector pin is placed.
[0016]
The stage 3 is for moving the measurement target 2 in a plane perpendicular to the optical axis of the optical system 6, and can move in the X and Y directions with respect to the base 8.
[0017]
The movement of the stage 3 is performed based on a movement command signal 11f from the control unit 11.
[0018]
The lamp 4 is provided in a base 8 below the stage 3 and illuminates the measurement target 2. The illumination light amount of the lamp 4 changes according to a change in the power supplied from the light amount correction unit 5. As the lamp 4, for example, a halogen bulb is used.
[0019]
The light amount correction unit 5 controls the light amount of the lamp 4 based on the light amount control signal 11a from the control unit 11.
[0020]
The optical system 6 is provided above the stage 3 and forms an enlarged image of the measurement target 2 illuminated by the lamp 4 and has a zoom function.
[0021]
The CCD camera 7 is provided above the optical system 6, takes in an image formed by the optical system 6, and outputs an image signal 7a corresponding to the light amount of the image.
[0022]
The computer 10 captures the image signal 7a of the CCD camera 7, performs predetermined processing, and controls the light amount adjusting unit 5.
[0023]
The computer 10 includes a control unit (correction value calculation unit) 11, a received light amount calculation unit (detection unit) 12, and a comparison unit 13.
[0024]
The control unit 11 has a memory (storing unit) 14 for storing a measurement program, a reference value described later, and the like.
[0025]
The control unit 11 calculates a correction value based on the value of the illumination light amount and the reference value stored in the memory 14.
[0026]
The control unit 11 controls the received light amount calculation unit 12 and the comparison unit 13 according to a preset measurement procedure (program), and outputs a light amount control signal 11a such as a correction value.
[0027]
Upon receiving the light receiving amount calculation command 11b from the control unit 11, the received light amount calculating unit 12 calculates the illumination light amount based on the image signal 7a from the CCD camera 7 with reference to, for example, a data conversion table. The calculation result is output to the comparison unit 13.
[0028]
When receiving the comparison instruction 11c from the control unit 11, the comparison unit 13 compares the calculation result with a reference value stored in the memory 14 in advance, and outputs a signal 13a indicating the comparison result.
[0029]
FIG. 2 is a flowchart for explaining a procedure for obtaining a reference value for light quantity correction, and S1 to S7 indicate each step of the process.
[0030]
The acquisition of the reference value is performed using a specific image measuring device (not shown) serving as a reference.
[0031]
First, the stage is moved to place a measurement target, which serves as a reference for detecting the amount of light, such as the calibration plate or the glass surface of the stage, at a predetermined position (S1).
[0032]
Next, the optical system is adjusted so as to focus on the reference measurement object (S2).
[0033]
After that, an illumination method (epi-illumination or transmission illumination) is selected (S3).
[0034]
Next, the illumination light amount is set to a predetermined light amount value (S4).
[0035]
This process is performed by changing the power supplied from the light amount correction unit to the lamp by a volume (not shown) of a specific image measuring device.
[0036]
Thereafter, a gray level image signal is obtained from the CCD camera, and the value of the illumination light amount calculated based on the image signal is set as a reference value (S5).
[0037]
Next, the reference value is stored in a specified file (for example, a flexible disk) (S6).
[0038]
Finally, the reference values obtained in the above steps 1 to 6 are stored in the memory 14 of an image measuring device (another device) other than the specific image measuring device (S7).
[0039]
FIG. 3 is a flowchart for explaining a procedure for acquiring a light quantity correction value, and S11 to S17 show each step of the processing.
[0040]
The acquisition of the light amount correction value (correction value) is performed using an image measuring device other than the specific image measuring device serving as a reference. Here, the procedure for acquiring the correction value using the image measuring device shown in FIG. explain.
[0041]
First, the stage 3 is moved in order to place a measurement target 2 which is a reference such as a calibration plate or a glass surface of a stage at a predetermined position (S11).
[0042]
Next, the optical system 6 is adjusted so that the measurement target 2 serving as a reference is focused (S12).
[0043]
Thereafter, an illumination method (transmission illumination in the case of FIG. 1) is selected (S13).
[0044]
Next, the illumination light amount is set to a predetermined light amount value (S14).
[0045]
This process is performed by changing the electric power supplied from the light amount correction unit 5 to the lamp 4 by a volume (not shown) of the image measuring device.
[0046]
Thereafter, a gray-level image signal is obtained from the CCD camera 7, and the illumination light amount is calculated based on the image signal (S15).
[0047]
Next, a correction value is calculated based on the value of the illumination light amount and the reference value stored in the memory 14 (S16).
[0048]
Finally, the correction value is stored in the memory 14 (S17).
[0049]
When executing the measurement program after performing the above processing, the illumination light amount is corrected based on the above correction value, and the same illumination light amount is obtained in all the measuring devices.
[0050]
According to this embodiment, it is possible to easily cope with changes and variations in the illumination light amount due to aging of the illumination light source and machine differences without modifying the measurement program.
[0051]
In the above embodiment, the case where the machine difference is corrected has been described, but it is possible to cope with a decrease in the illumination light amount due to aging.
[0052]
【The invention's effect】
As described above, according to the present invention, when the measurement operation is performed, the illumination light amount is corrected using the correction value, so that the illumination light amount can easily cope with changes and variations in the illumination light amount due to aging of the illumination light source and machine differences. can do.
[Brief description of the drawings]
FIG. 1 is a block diagram of a light quantity correction device of a measuring instrument according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a procedure for obtaining a reference value for light amount correction.
FIG. 3 is a flowchart illustrating a procedure for obtaining a light amount correction value.
[Explanation of symbols]
5 Light intensity correction unit (light intensity correction means)
7 CCD camera 12 Light reception amount calculation unit (detection means)
11 control unit (correction value calculation means)
14 memory (storage means)

Claims (2)

When a reference value of the amount of illumination light is acquired using a reference measurement device, the reference value is stored in a measurement device other than the reference measurement device, and a measurement device other than the reference measurement device is used. And correcting the amount of illumination light using the reference value. Storage means for storing a reference value of the amount of illumination light, calculated using a measuring instrument serving as a reference,
Detecting means for detecting the amount of illumination light;
Correction value calculation means for calculating a correction value based on the value of the illumination light amount detected by the detection means and the reference value stored in the storage means,
A light amount correcting device for correcting the amount of illumination light based on the correction value.

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