JP2010256282A - Two-dimensional measuring machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-dimensional measuring machine including an illumination device, capable of imaging a measuring object with a high contrast at all times, and acquiring sufficient light quantity at all times. <P>SOLUTION: In the two-dimensional measuring device includes a microscope (5) for enlarging the measuring object (1), and an illumination means (11) for illuminating the measuring object, the illumination means includes a plurality of LED illuminations (12) for emitting each a light (14), having respective different wavelength (λ<SB>1</SB>, λ<SB>2</SB>, λ<SB>3</SB>, λ<SB>4</SB>, λ<SB>5</SB>), and a light (14) emitted from one LED illumination selected from among q plurality of LED illuminations is converted into a parallel beam by a collimator lens (13) and is reflected toward a measuring spot (20) by a translucent prism (16) arranged in the microscope. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pattern inspection apparatus used for inspecting whether or not a pattern of a transparent conductive film such as an ITO (indium tin oxide) film in a liquid crystal panel matches a design drawing, or a two-dimensional measurement for measuring the dimension of the pattern, etc. Related to measuring machine.

  As a conventional liquid crystal panel pattern inspection apparatus, the one shown in FIG. 3 is known (see Patent Document 1 below).

  The pattern inspection apparatus is obtained by a table 9 on which a liquid crystal panel 1 as a measurement object is placed, a microscope 5 for enlarging a measurement location of the measurement object 1, a CCD camera 6 attached to the microscope 5, and a CCD camera 6. An image processing apparatus for processing the image, and a table driving device 8 for moving the measurement table 9 in the X-axis direction and the Y-axis direction within a horizontal plane. Then, based on the image obtained by the CCD camera 6, the two-dimensional coordinates of the positioning mark 2 relating to the pattern of the ITO film (see FIG. 4) formed on the liquid crystal panel 1 are measured, and the liquid crystal panel 1 is designed. It was inspected whether it was manufactured as shown in the figure.

  By the way, when the pattern of the ITO film which is the conductive film on the glass substrate 1a in the liquid crystal panel 1 is imaged by the CCD camera 6, the contrast of the captured image is low, and accurate measurement may be difficult. This is because the light reflected on the surface of the ITO film and the light reflected on the lower surface of the ITO film interfere with each other and weaken, resulting in a low-contrast image.

As shown in FIG. 4, the optical path difference D between the light reflected by the surface of the ITO film and the light reflected by the lower surface of the ITO film is d for the thickness of the ITO film, n for the refractive index of the ITO film, and If the refractive index is n ₁ , the refractive index of the glass substrate 1 a is n ₂ (where n ₁ = 1 <n <n ₂ ), and the wavelength of light is λ, then D = 4πnd / λ. Therefore, when the optical path difference D is D = (2m + 1) π (where m is an integer) with respect to the light wavelength λ, the light reflected on the surface of the ITO film and the light reflected on the lower surface of the ITO film Interfere with each other and weaken, resulting in a low contrast image. On the other hand, when D = 2mπ, the light reflected on the surface of the ITO film and the light reflected on the lower surface of the ITO film interfere with each other and strengthen each other, resulting in a high-contrast image.

  Therefore, in the pattern inspection apparatus described in Patent Document 1 below, a plurality of interference filters 4 are arranged between the light source 3 and the microscope 5, the motor 10 is rotated to switch the interference filter 4, and the light emitted from the light source 3. Among them, light having a wavelength capable of obtaining the highest contrast image is selected by the interference filter 4 and sent to the microscope 5 to illuminate the liquid crystal panel 1. Thus, a high-contrast image was obtained.

JP-A-6-174448

  However, in the pattern inspection apparatus, only a small amount of light having a wavelength that passes through the interference filter 4 out of the light emitted from the light source 3 is used for illuminating the object to be measured, and other light than the light emitted from the light source 3 is used. There is a problem that light of a wavelength is blocked by the interference filter 4, and as a result, a sufficient amount of light cannot be obtained.

  The present invention has been made in view of the above problems, and in a two-dimensional measuring machine equipped with illumination means, it is possible to always capture a measurement object with high contrast and always obtain a sufficient amount of light. The task is to do.

  In order to solve the above-described problem, in the invention according to claim 1, in the two-dimensional measurement apparatus including a microscope for magnifying a measurement object and an illumination unit for illuminating the measurement object, the illumination unit has different wavelengths. A plurality of LED illuminations for emitting light, and LED selection means for illuminating the measurement object with light from one LED illumination selected from the plurality of LED illuminations.

  In the invention which concerns on Claim 2, in the invention which concerns on Claim 1, the said measurement object is a pattern produced | generated by the transparent conductive film on a glass substrate, The said LED selection means uses for the measurement by the film thickness of the said pattern LED lighting is selected.

  In the invention according to claim 3, in the invention according to claim 1, the LED selection means illuminates the measurement object with light from one LED illumination sequentially selected from the plurality of LED illuminations, When the contrast at a predetermined location on the measurement object is equal to or higher than a threshold value, the LED illumination is selected for use in measurement.

  In the invention according to claim 4, in the invention according to claim 3, when the measurement object is illuminated with any of the plurality of LED illuminations and the contrast does not exceed the threshold value, the contrast is the highest. It is characterized in that the enlarged LED illumination is selected for use in the measurement.

  According to the invention which concerns on Claim 1, an illuminating means makes the said measurement object with the light from one LED illumination selected from among several LED illumination which each radiate | emits the light of a different wavelength, and these LED illumination. Since the LED selection means for illuminating is provided, the LED illumination that emits light of a wavelength that can image the measurement object with the highest contrast is turned on, and the light emitted from the LED illumination is kept at a sufficient amount of light up to the measurement object. It can be guided as it is. Thereby, a measurement object can always be imaged with high contrast.

  According to the second aspect of the present invention, the measurement object is a pattern generated by the transparent conductive film on the glass substrate, and the LED selection unit selects the LED illumination to be used for measurement according to the film thickness of the pattern. The LED illumination to be used for measurement can be selected quickly and automatically, and the measurement work can be performed easily in a short time.

  According to the invention of claim 3, the LED selection means illuminates the measurement object with light from one LED illumination sequentially selected from among the plurality of LED illuminations, and a predetermined place on the measurement object is illuminated. When the contrast exceeds a threshold value, the LED illumination is selected to be used for measurement. Therefore, the LED illumination to be automatically used can be selected to facilitate measurement work.

  According to the fourth aspect of the present invention, when the object to be measured is illuminated with any of the plurality of LED illuminations, if the contrast does not exceed the threshold value, the LED illumination with the highest contrast is measured. Therefore, even when the contrast does not exceed the threshold value, the measured value is obtained, and it is not necessary to take time for error processing, so that the measurement work can be performed more easily.

It is a figure explaining the structure of the two-dimensional measuring machine of this invention. It is a figure explaining the procedure which measures a measurement object with the said two-dimensional measuring machine. It is a figure explaining the structure of pattern inspection apparatuses, such as the conventional liquid crystal panel. It is a figure explaining the case where the conventional pattern inspection apparatus cannot obtain a high-contrast image.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram illustrating the configuration of the two-dimensional measuring machine according to the present embodiment. FIG. 2 is a flowchart for explaining a procedure when measuring a measurement object with the two-dimensional measuring machine.

  As shown in FIG. 1, the two-dimensional measuring machine includes a microscope 5 that expands a measurement location 20 on a measurement object such as a liquid crystal panel 1 and an illumination unit 11 that illuminates the liquid crystal panel 1. Of course, similarly to the conventional one shown in FIG. 3, a CCD camera, an image processing device, a table driving device and a table (not shown) are also provided.

However, the illumination means 11 of this two-dimensional measuring machine includes a plurality of LED (light emitting diode) illuminations 12 that emit light of different wavelengths (λ ₁ , λ ₂ , λ ₃ , λ ₄ , λ ₅ ), and a plurality of Among the LED illuminations 12, an LED selection unit that illuminates the measurement object with the light 14 emitted from the selected one LED illumination 12. The light 14 emitted from the LED illumination 12 is converted into a parallel light beam by the collimator lens 13 and reflected by the half mirror 16 disposed in the microscope 5 toward the measurement location 20 along the optical axis of the microscope 5.

  As an example of the LED selection means, a rotating plate 18 in which the LED lighting 12 is arranged and fixed in a circle is provided, and the rotating plate 18 is rotated by the rotating shaft 15 so that only the LED lighting 12 facing the collimator lens 13 is provided. It lights up and only the light 14 from this LED illumination 12 illuminates the measurement location 20 as epi-illumination light. The LED selection means further includes a program (not shown), a CPU (not shown) for executing the program, a motor (not shown) for rotating the rotating plate 18 according to an instruction from the CPU, and an instruction from the CPU. A switch (not shown) for turning on or off each LED illumination 12 and positioning means (not shown) using a revolver are provided.

Of course, the number of LEDs 12 is not limited to five as shown in FIG. 1, and an appropriate number of two or more can be selected, and the wavelength of light emitted from each LED 12 must be limited to the visible light range. No, it may extend from the infrared region to the ultraviolet region.
Next, based on FIG. 2, the CPU executes the two-dimensional coordinate measuring unit 20 to measure the two-dimensional coordinates and the like of each part of the measurement point 20 (ITO film pattern, etc.) on the liquid crystal panel 1 as a measurement object. The procedure of the program to be executed will be described.

  When measurement is started, first, the process proceeds to step S1 to start capturing an image, and the LED illumination 12 facing the collimator lens 13 is turned on. Next, the process proceeds to step S2, and the contrast at a predetermined location on the liquid crystal panel 1 is detected in the captured image.

  Next, the process proceeds to step S3, and it is checked whether or not the contrast at a predetermined location is equal to or greater than a predetermined threshold value. If the contrast is less than the threshold value, the process proceeds to step S4 to check whether all the LED lights 12 are turned on. If all the LED lights 12 are not turned on, the process proceeds to step S5, the lighted LED lights 12 are turned off, the rotating plate 18 is rotated, the next LED light 12 is turned on, and step S2 is turned on. Return to. Thereafter, steps S2 to S5 are repeated until the contrast becomes equal to or greater than the threshold value. If all the LED lights 12 are turned on in step S4, the process proceeds to step S6, and the LED lights 12 having the highest contrast at a predetermined location are selected and turned on in all the LED lights 12. The process proceeds to step S7.

  If the contrast is equal to or greater than the threshold value in step S3, the process proceeds to step S7 to perform measurement, and then proceeds to step S8 to complete the image capture and turn off the lit LED illumination 12. This measurement is finished.

  According to the present embodiment, the illuminating means 11 measures the liquid crystal panel 1 or the like with light from a plurality of LED illuminations 12 that emit light of different wavelengths and one LED illumination 12 selected from the plurality of LEDs 12. Since the LED selection means for illuminating the object is provided, the LED illumination 12 that emits light having a wavelength capable of imaging the measurement object with the highest contrast is selected, and the light emitted from the LED illumination 12 is lost to the measurement object as much as possible. It can be guided to a small extent. Moreover, the LED illumination 12 emits only light having a specific wavelength. Thus, the measurement location 20 on the liquid crystal panel 1 can always be imaged with high contrast. Moreover, since the LED illumination 12 to be used automatically can be selected, measurement work can be performed easily. Furthermore, even if the measured object is illuminated with any of the plurality of LED lights 12, even when the contrast does not exceed the threshold value, a measured value is obtained and time is not taken for error processing. Can be done more easily.

  By the way, the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, in the above-described embodiment, the LED illumination 12 used for measurement is automatically selected. However, the operator looks at the monitor screen and selects the LED illumination 12 having the highest contrast or the threshold value or more. It may be. Moreover, in the said Example, when the wavelength of the light radiate | emitted from the illumination means 11 was changed sequentially and the contrast became more than a threshold value, the LED illumination at that time was selected, but the film thickness meter is provided. If the film thickness d can be measured in advance, the LED illumination 12 that emits light having a wavelength closest to the wavelength λ satisfying 2πnd / λ = 2mπ may be selected and turned on. Here, n is the refractive index of the film, and m is an integer. Furthermore, the present invention can be used for the inspection of a thin film pattern formed on the surface of another measurement object in addition to the inspection of the ITO film pattern formed on the surface of the liquid crystal panel 1.

1 LCD panel (measurement)
1a glass substrate 5 microscope 12 LED illumination (illumination means)
14 Light 18 Rotating plate (LED selection means)
ITO Indium tin oxide (transparent conductive film)

Claims (4)

In a two-dimensional measurement apparatus comprising a microscope for magnifying a measurement object and an illumination means for illuminating the measurement object,
The illumination unit includes a plurality of LED illuminations that emit light of different wavelengths, and an LED selection unit that illuminates the measurement object with light from one LED illumination selected from the plurality of LED illuminations. A two-dimensional measuring apparatus characterized by that.   The said measurement object is a pattern produced | generated by the transparent conductive film on a glass substrate, The said LED selection means selects the LED illumination used for a measurement with the film thickness of the said pattern. Two-dimensional measuring device.   The LED selection means illuminates the measurement object with light from one LED illumination sequentially selected from the plurality of LED illuminations, and the contrast at a predetermined location on the measurement object exceeds a threshold value. 2. The two-dimensional measuring apparatus according to claim 1, wherein the LED illumination is selected for use in measurement.   If the contrast does not exceed the threshold value when the object to be measured is illuminated with any of the plurality of LED lights, the LED light with the highest contrast is selected for use in measurement. The two-dimensional measuring apparatus according to claim 3.

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