JP2012078151A - Inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically compensate for deterioration of illumination light by acquiring an optical spectrum after the passage of the illumination light through an objective lens.SOLUTION: The inspection device 1 includes a spectral measuring part 13 for acquiring an optical spectrum of illumination light made incident on an image sensor 123 after passage through an objective lens 121 from an object to be illuminated having known spectral characteristics, and a control unit 14 for correcting a system function represented by the product of the spectral sensitivity of the image sensor 123 and the optical spectrum of the illumination light acquired by the spectral measuring part 13 so as to be a predetermined target value.

Description

  The present invention relates to an inspection apparatus that illuminates and inspects an inspection object.

  In a conventional inspection apparatus, a spectrometer is used when measuring a spectral spectrum of illumination light that illuminates an inspection object. In Patent Document 1, in order to reduce the estimation error of the spectral characteristics due to the non-uniformity of the illumination radiation distribution of the illumination light, and to improve the estimation accuracy of the spectral characteristics of the subject, the spectral radiation characteristics of the divided areas of the illumination image are disclosed. An image processing apparatus that measures the above is disclosed. In addition, in Patent Document 2, when a denture is manufactured, a patient's tooth part is imaged while emitting a plurality of illumination light LEDs having different wavelengths by an imaging device, and a denture that matches the color of the patient's tooth part is obtained. An image processing system for measuring illumination light with a spectrum detection sensor for manufacturing is disclosed.

JP 2009-25147 A International Publication No. 02004/036162

  However, the techniques described in Patent Document 1 and Patent Document 2 cannot prevent the influence of deterioration of illumination light when inspecting an inspection object.

  In order to solve the above problems, an object of the present invention is to provide an inspection apparatus capable of accurately determining deterioration of illumination light and automatically compensating for deterioration of illumination light.

  In order to solve the above problems, an inspection apparatus according to the present invention includes an illumination unit having a light source, and an inspection unit having an objective lens and an image sensor, and illuminates an inspection object with illumination light from the light source, An inspection apparatus that inspects an inspection object by forming an image of an object on the image sensor, and a spectral spectrum of illumination light incident on the image sensor from an object to be illuminated having a known spectral characteristic through the objective lens Control for correcting the system function represented by the product of the spectral sensitivity of the imaging device and the spectral sensitivity of the imaging device and the spectral spectrum of the illumination light acquired by the spectral measurement unit to a predetermined target value And a section.

  Further, in the inspection apparatus according to the present invention, when the difference between the spectral spectrum of the illumination light stored in advance and the spectral spectrum of the illumination light acquired by the spectral measurement unit is greater than a predetermined threshold, the control unit It is characterized by correcting the function.

  In the inspection apparatus according to the present invention, the control unit performs the comparison every time the inspection unit images the inspection object, and corrects the system function when the difference is larger than a predetermined threshold value. It is characterized by.

  In the inspection apparatus according to the present invention, the control unit performs the comparison every time an inspection object is imaged by the inspection unit until a predetermined time during which illumination light is stabilized after the light source is turned on. The system function is corrected when the difference is larger than a predetermined threshold value.

  In the inspection apparatus according to the present invention, the control unit performs the comparison every time a lighting time of the light source elapses a predetermined time, and when the difference is larger than a predetermined threshold, It is characterized by correcting.

  Further, in the inspection apparatus according to the present invention, the control unit performs the comparison when the cumulative lighting time of the light source exceeds an expected life time, and when the difference is larger than a predetermined threshold, the system function It is characterized by correcting.

  In the inspection apparatus according to the present invention, the target value includes a target value for a normal mode and a target value for an energy saving mode that is smaller than the target value for the normal mode.

  In the inspection apparatus according to the present invention, the inspection object is held in a preparation, and the object to be illuminated is a portion where the inspection object of the preparation does not exist.

  In the inspection apparatus according to the present invention, the inspection unit is a microscope.

  According to the present invention, the system function obtained from the spectral spectrum of the illumination light after passing through the objective lens is corrected so as to have a predetermined target value, thereby accurately determining the deterioration of the illumination light, It becomes possible to automatically compensate for the deterioration of light.

It is a block diagram which shows the structure of the test | inspection apparatus of 1st Embodiment by this invention. It is a block diagram which shows the structure of the control part of the inspection apparatus of 1st Example by this invention. It is a flowchart which shows operation | movement of the test | inspection apparatus of 1st Embodiment by this invention. It is a block diagram which shows the modification of the inspection apparatus of 1st Embodiment by this invention. It is a block diagram which shows the structure of the inspection apparatus of 2nd Embodiment by this invention. It is a flowchart which shows operation | movement of the test | inspection apparatus of 2nd Embodiment by this invention. It is a figure which shows the structure of a preparation. It is a figure explaining the spectroscopic measurement of the inspection apparatus of 2nd Embodiment by this invention.

  Embodiments of an inspection apparatus according to the present invention will be described below in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of the inspection apparatus according to the first embodiment of the present invention. The inspection apparatus 1 includes an illumination unit 11, an inspection unit 12, a spectroscopic measurement unit 13, and a control unit 14.

  The illumination unit 11 emits illumination light by turning on the light source 111 to irradiate the inspection object 15 placed on the stage 16. In the present embodiment, the illumination light emitted from the illumination unit 11 is applied to the inspection object 15 via the half mirror 122 and the objective lens 121 of the inspection unit 12. Further, the illumination unit 11 guides the light that passes through the objective lens 121 and is incident from the inspection unit 12 to the spectroscopic measurement unit 13 via the half mirror 112.

  The inspection unit 12 captures an image of the inspection object 15 that has passed through the objective lens 121 with an image sensor 123 such as a CCD or a CMOS. The inspection unit 12 guides the light that has passed through the objective lens 121 to the illumination unit 11 via the half mirror 122.

  For example, the inspection unit 12 is a microscope, and the inspection object 15 is a pathological specimen. In this case, the inspection unit 12 has an eyepiece lens between the half mirror 122 and the image sensor 123 and acquires an enlarged image of the inspection object 15. Further, the inspection unit 12 may include an image processing unit. In this case, the image processing unit performs image processing on the image captured by the image sensor 123 and analyzes the image.

  The spectroscopic measurement unit 13 performs spectroscopic measurement of illumination light incident through the half mirror 122 of the illumination unit 11 and acquires a spectroscopic spectrum. Since the spectral spectrum changes due to chromatic aberration or the like when passing through the objective lens 121, the spectroscopic measurement unit 13 performs spectroscopic measurement of the illumination light after passing through the objective lens 121. When performing spectroscopic measurement, an object to be illuminated (inspected object 15 in this embodiment) having a known spectral characteristic is used. For example, as shown in FIG. 1, when the illumination light is epi-illumination, the inspection object 15 having a known reflectance is used, and when the illumination light is transmission illumination, the inspection object 15 having a known transmittance is used. Is done.

  The control unit 14 controls operations of the illumination unit 11, the inspection unit 12, and the spectroscopic measurement unit 13.

  FIG. 2 is a block diagram illustrating a configuration of the control unit 14. The control unit 14 includes a spectroscopic measurement control unit 141 that controls the operation of the spectroscopic measurement unit 13, an illumination data determination unit 142 that determines whether or not the illumination light data of the illumination unit 11 is degraded, and the illumination light is degraded. A warning unit 143 that issues a warning in the event of a failure, an illumination control unit 144 that controls the operation of the illumination unit 11, and an inspection control unit 145 that controls the operation of the inspection unit 12.

  The operation of the control unit 14 will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of the control unit 14 of the inspection apparatus 1. In step S <b> 101, the control unit 14 causes the illumination control unit 144 to turn on the light source 111 of the illumination unit 11, and the spectroscopic measurement control unit 141 emits light from the illumination unit 11 and passes through the objective lens 121. Measure and acquire the spectrum.

  In step S102, the control unit 14 causes the illumination data determination unit 142 to compare the spectral spectrum of the illumination light acquired in step S102 with the spectral spectrum in the ideal state after passing through the objective lens 121 stored in advance. When the difference between the spectral spectra is larger than a predetermined threshold, it is determined that the illumination light has deteriorated. The spectrum in the ideal state may be stored in the illumination data determination unit 142 or read from another storage unit (not shown).

  Here, the difference includes a difference value determined by various methods such as variance, sum of absolute values of difference, product of absolute values of difference, minimum value of absolute value of difference, or sum of squares of difference. And

  When it determines with the illumination light of the illumination part 11 having deteriorated in step S102, the control part 14 issues a warning by the warning part 143 in step S103 as needed. For example, the warning is issued by a method such as sounding a warning sound, flashing the LED when the control unit 14 has a warning LED, or displaying a warning message when the control unit 14 has a display unit.

In step S104, the control unit 14 uses the illumination control unit 144 to calculate the system function H (λ), and sets the calculated system function H (λ) to a target value H _T (λ) of a predetermined system function. Correct to match. The target value H _T (λ) of the system function may be stored in the illumination control unit 144 or may be read from another storage unit (not shown).

Here, the system function H (λ) means that the spectral sensitivity of the image sensor 123 is S (λ), and the spectral spectrum of the illumination light that passes through the objective lens 121 and enters the image sensor 123 is I (λ). , H (λ) = S (λ) × I (λ). When the spectral spectrum I (λ) changes (deteriorates), the system function H (λ) also changes. Therefore, the signal output from the image sensor 123 is corrected to compensate for the deterioration of the illumination light of the light source 111. That is, the system function H (λ) is matched with the target value H _T (λ) of the system function by multiplying by H _T (λ) / H (λ). When only the power of the spectral spectrum I (λ) has decreased, the power of the illumination light of the light source 111 is increased, and I (λ) is increased, whereby the system function H (λ) is changed to the target value H _T. (Λ) may be matched.

A plurality of system function target values H _T (λ) may be provided. For example, a target value H _T1 (λ) in the normal mode and a target value H _T2 (λ) in the energy saving mode are provided, and the target value H _T2 (λ) in the energy saving mode is equal to the target value H _T1 (λ in the normal mode). ), And the illumination light power may be minimized. The illumination light is corrected by the above operation.

  Thereafter, in step S105, the control unit 14 images the inspection object 15 by the inspection control unit 145.

  In this flowchart, the control unit 14 determines the illumination light every time the imaging object 15 is imaged, but the timing for determining the illumination light is not limited to this. For example, since a predetermined time (for example, 1 hour) is required until the illumination light is stabilized after the light source 111 is turned on, the control unit 14 determines the time required for the illumination light to be stabilized every time the inspection object 15 is imaged. It may be determined whether or not it has elapsed, and when it is determined that it has not elapsed, the illumination light may be determined. Further, the control unit 14 may measure the lighting time of the light source 111 and determine the illumination light every time a predetermined time such as 24 hours, 1 week, or 1 month elapses. Further, the control unit 14 stores the accumulated lighting time of the light source 111 and determines the illumination light when the estimated life time is exceeded, and the illumination is performed at short intervals as the light quantity decreases or the estimated lifetime is exceeded. You may make it perform determination of light.

  Furthermore, the timing for determining the illumination light is not only based on the passage of time, but the illumination light is determined when an optical component such as a lens or a filter is replaced or when the inspection unit 12 is focused. You may do it.

  The inspection apparatus 1 is not limited to the configuration illustrated in FIG. 1, and the illumination unit 11 may include a spectroscopic measurement unit 13 as illustrated in FIG. 4. By adopting such an integrated configuration, the size of the inspection apparatus 1 can be reduced.

  In particular, the spectroscopic measurement unit 13 preferably includes a light diffusing member 131 that diffuses light and a sensor 132 that has a plurality of regions and a different color filter for each region. By using such a sensor 132, the spectroscopic measurement unit 13 can be reduced in size and the size of the inspection apparatus 1 can be reduced as compared with the case where a rotating color filter is used.

Thus, according to the inspection apparatus 1 of the first embodiment, the illumination is always inspected 15 by correcting the system function H (λ) so as to match the target value H _T (λ) of the system function. Therefore, it is possible to prevent the influence of deterioration of illumination light when analyzing a captured image. Further, by measuring the spectral spectrum of the illumination light after passing through the objective lens 121, the spectral spectrum of the illumination light incident on the image sensor 123 can be accurately measured.

  Further, by determining the illumination light based on the passage of time, it is possible to automatically determine whether or not the illumination state at that time is appropriate for the inspection, and to obtain an appropriate illumination. When the lens or filter is exchanged, the illumination light is determined so that the inspection can be performed in an illumination state suitable for each lens or filter. By determining the illumination light when the inspection unit 12 is focused, the inspection can be performed in an illumination state suitable for the focus.

Further, by providing the target value H _T2 (λ) of the system function for the energy saving mode, it is possible to minimize the power cost.

(Second Embodiment)
Next, the inspection apparatus 2 according to the second embodiment of the present invention will be described. FIG. 5 is a block diagram showing the configuration of the inspection apparatus according to the second embodiment of the present invention. The inspection unit 12 of the inspection apparatus 2 is a microscope and includes an eyepiece lens 124. Illumination light emitted from the illuminating unit 11 is condensed on the illumination location a on the stage 16 via the half mirror 112 and the condenser lens 113, and the transmitted light is incident on the image sensor 123. Although the case where the illumination light is transmissive as shown in FIG. 5 will be described below, the illumination light may be incident light.

  The inspection apparatus 2 includes an inspection object moving unit 17. The inspection object moving unit 17 moves the stage 16 or the inspection unit 12 in the horizontal direction and moves the inspection object 15 relative to the inspection unit 12 under the control of the control unit 14.

  The inspection object 15 is held by a preparation set on the stage 16. As shown in FIG. 7, the preparation 3 includes a slide glass 31 and a cover glass 32, and the inspection object 15 is held stationary between the slide glass 31 and the cover glass 32.

  When performing the spectroscopic measurement, the inspection apparatus 2 according to the present embodiment uses a portion where the inspection object 15 does not exist on the preparation 3 as an object to be illuminated, and performs spectroscopic measurement of illumination light irradiated on the portion where the inspection object 15 does not exist. I do.

  FIG. 6 is a flowchart showing the operation of the control unit 14 of the inspection apparatus 2. In step S201, the control unit 14 moves the inspection object 15 by the inspection object moving unit 17, and the slide glass 31 portion where the inspection object 15 does not exist is arranged at the illumination location a as shown in FIG. To be controlled. Or when the preparation 3 with which the test object 15 does not exist regularly is arrange | positioned, as shown in FIG.8 (b), the control part 14 is the preparation 3 with which the test object 15 does not exist in the illumination location a. You may control so that the cover glass 32 part of this may be arrange | positioned.

  The operation from step S202 to step S205 is the same as the operation from step S101 to step S104 shown in FIG. The illumination light is corrected by the above operation. Note that after warning in step S204, the user may be prompted to replace the preparation 3, and spectral measurement may be performed again.

  Thereafter, in step S206, the control unit 14 moves the inspection object 15 by the inspection object moving unit 17, and controls so that the cover glass 32 portion holding the inspection object 15 is disposed at the illumination location a. In step S207, the control unit 14 images the inspection object 15 by the inspection control unit 145.

  The spectroscopic measurement may be performed at a plurality of locations where the inspection object 15 does not exist. Further, as shown in FIG. 8C, if the spectral spectrum measurement of the transmitted light is performed in the portion of the slide glass 31 and the portion without the preparation 3, the slide glass 31 is obtained from the spectral spectrum of the portion without the preparation 3. It can be distinguished whether the spectral spectrum of the portion has changed or a movement error of the inspection object moving unit 17.

As described above, according to the inspection apparatus 2 of the second embodiment, the inspection object 15 is compared with the spectral spectrum of the transmitted light of the glass portion where the inspection object 15 does not exist and the spectrum spectrum of the known ideal state. Thus, the system function H (λ) can be corrected so as to match the target value H _T (λ) of the system function without being influenced by the above-mentioned, that is, without considering the spectral characteristics of the inspection object 15. .

  Each of the above embodiments has been described as a representative example, but it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1, 2 Inspection apparatus 11 Illumination part 12 Inspection part 13 Spectroscopic measurement part 14 Control part 15 Inspection object 16 Stage 17 Inspection object moving part 111 Light source 112,122 Half mirror 113 Condensing lens 121 Objective lens 123 Imaging element 131 Light diffusion member 132 Sensor 141 Spectroscopic measurement control unit 142 Illumination data determination unit 143 Warning unit 144 Illumination control unit 145 Inspection control unit

Claims (9)

An illumination unit having a light source; and an inspection unit having an objective lens and an image pickup device, illuminating the inspection object with illumination light from the light source, and forming an image of the inspection object on the image pickup device. An inspection device for inspecting
A spectroscopic measurement unit that obtains a spectral spectrum of illumination light incident on the imaging element from the object to be illuminated having a known spectral characteristic through the objective lens;
A control unit that corrects the system function represented by the product of the spectral sensitivity of the image sensor and the spectral spectrum of the illumination light acquired by the spectroscopic measurement unit to be a predetermined target value;
An inspection apparatus comprising:   The control unit corrects the system function when a difference between a spectral spectrum of illumination light stored in advance and a spectral spectrum of illumination light acquired by the spectroscopic measurement unit is larger than a predetermined threshold, The inspection apparatus according to claim 1.   3. The control unit according to claim 2, wherein the control unit performs the comparison every time an inspection object is imaged by the inspection unit, and corrects the system function when the difference is larger than a predetermined threshold value. Inspection equipment.   The control unit performs the comparison every time an image of the inspection object is imaged by the inspection unit until a predetermined time during which illumination light is stabilized after the light source is turned on, and the difference is greater than a predetermined threshold value. The inspection apparatus according to claim 2, wherein the system function is corrected.   The control unit performs the comparison every time a lighting time of the light source passes a predetermined time, and corrects the system function when the difference is larger than a predetermined threshold. 2. The inspection apparatus according to 2.   The control unit performs the comparison when the cumulative lighting time of the light source exceeds an expected life time, and corrects the system function when the difference is larger than a predetermined threshold. Item 3. The inspection apparatus according to Item 2.   The target value includes a target value for a normal mode and a target value for an energy saving mode that is smaller than the target value for the normal mode. The inspection device described in 1.   The inspection apparatus according to claim 1, wherein the inspection object is held by a slide, and the object to be illuminated is a portion where the inspection object of the preparation does not exist.   The inspection apparatus according to claim 1, wherein the inspection unit is a microscope.

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