JP2005345117A - Hardness testing instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the measuring precision of hardness by enhancing automatic focus matching precision when the dimension of a cavity is measured in a hardness testing instrument. <P>SOLUTION: The hardness testing instrument 1 is constituted so that the cavity K is formed in the surface of a sample S using an indenter 34 and the dimension of the cavity K is measured to calculate the hardness of the sample S and equipped with an imaging means (CCD camera 31) for imaging the surface of the sample S to acquire predetermined image data, an automatic focus matching means (CPU 10a, an automatic focus matching program and an AF control mechanism 32) for performing automatic focus matching when the dimension of the cavity K is measured on the basis of the image data acquired by the imaging means and a focus matching image region setting means (CPU 10a and a focus matching image region setting program) capable of setting image regions (focus matching image regions) A<SB>2</SB>and A<SB>3</SB>used in automatic focus matching. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hardness tester, and more particularly to a hardness tester that measures the hardness of a sample based on the size of a recess formed on the surface of a predetermined sample.

  Conventionally, various hardness testers such as a Brinell hardness tester, a Vickers hardness tester, a Knoop hardness tester, etc., that measure the hardness of the sample based on the size of a recess formed on the surface of a predetermined sample. Has been proposed and put into practical use. For example, the Vickers hardness tester is equipped with a hardness measuring unit having a regular quadrangular pyramid indenter, and the length of the diagonal line of the depression formed by pushing the indenter into the surface of the sample is measured with an optical microscope or the like. The hardness is calculated based on the length of the diagonal line of the recess.

In the hardness tester as described above, when measuring the size of the recess, focusing is performed on the surface of the sample on which the recess is formed. In recent years, a hardness tester has been proposed that includes a moving means for moving the objective lens or sample of an optical microscope up and down, and an automatic focusing means for controlling the moving means to automatically focus the optical microscope. (For example, refer to Patent Document 1).
JP 2002-310869 A (first page, FIG. 1)

  By the way, in the conventional hardness tester as described in Patent Document 1, the surface of the sample is imaged by a CCD (Charge Coupled Device) camera or the like to acquire predetermined image information. Based on the automatic focusing. Image information acquired by a CCD camera or the like is displayed on a predetermined display screen 100 as shown in FIGS. An area surrounded by a thick line in the display screen 100 is an image area (focusing image area) 200 used for automatic focusing.

  However, in the conventional hardness tester, the position and width (area) of the focusing image area 200 cannot be arbitrarily changed. Therefore, when the end portion 300 of the sample is included in the focusing image area as shown in FIG. 6B, the image information (dark part) of the portion 400 where the sample does not exist is the entire focusing image area. This may affect the contrast of the camera and reduce the autofocus accuracy. Thus, when the automatic focusing accuracy is lowered, there is a problem that the measurement accuracy of the indentation dimension is lowered, and as a result, the hardness measurement accuracy is lowered.

  Further, in the above-described conventional hardness tester, the position and the width (area) of the focusing image area cannot be arbitrarily changed, so that it is affected by the depressions and bulges formed around the recess. As a result, the automatic focusing accuracy may decrease.

  The subject of this invention is improving the measurement precision of hardness by raising the automatic focusing precision at the time of measuring the dimension of a dent in a hardness tester.

In order to solve the above problems, the invention described in claim 1
A hardness tester (Vickers hardness test) for calculating the hardness of the sample by forming a recess (K) on the surface of a predetermined sample (S) using an indenter (34) and measuring the size of the recess In machine 1)
Imaging means (CCD camera 31) for imaging the surface of the sample and acquiring predetermined image information;
Automatic focusing means (CPU 10a, automatic focusing program and AF control mechanism 32) for performing automatic focusing when measuring the size of the indentation based on the image information acquired by the imaging means;
Focusing image area setting means (CPU 10a and focusing image area setting program) that enables setting of focusing image areas (A ₂ , A ₃ ) that are image areas used for the automatic focusing;
It is characterized by providing.

  According to the first aspect of the present invention, the position and width (area) of an image area (focusing image area) used for automatic focusing can be arbitrarily set by the focusing image area setting means. it can. Therefore, for example, it is possible to set an in-focus image area according to the size, shape, etc. of the sample, or to set an in-focus image area so as to avoid depressions and bulges formed around the recess. it can. As a result, the automatic focusing accuracy can be increased, and the measurement accuracy of the indentation dimension can be improved, and consequently the measurement accuracy of the hardness can be improved.

The invention according to claim 2 is the hardness tester according to claim 1,
The planar shape of the indentation is substantially rectangular,
The focusing image area setting means includes:
Set the focusing image area near the four corners of the indentation,
The automatic focusing means includes
Four in-focus position coordinates are calculated based on the image information of the four in-focus image areas (A ₃ ) set in the vicinity of the four corners of the recess, and automatic in-focus is performed based on these four in-focus position coordinates. It is characterized by performing scorching.

  According to the second aspect of the present invention, it is possible to set the focusing image area in the vicinity of the four corners of the indentation, and to set the four focusing areas based on the image information of the set four focusing image areas. Focus position coordinates can be calculated, and automatic focusing can be performed based on these four focus position coordinates. Therefore, it is possible to correct the variation in the focus position caused by the depression or the rise formed around the recess. As a result, the automatic focusing accuracy can be further increased, and further improvement in the measurement accuracy of the indentation size and further improvement in the measurement accuracy of the hardness can be brought about.

The invention according to claim 3 is the hardness tester according to claim 2,
The automatic focusing means includes
Of the four in-focus position coordinates, automatic focusing is performed using coordinates obtained by averaging two in-focus position coordinates excluding the minimum and maximum coordinates.

  According to the third aspect of the present invention, automatic focusing is performed using coordinates obtained by averaging two in-focus position coordinates excluding the minimum and maximum coordinates among the four in-focus position coordinates calculated. be able to. Therefore, even when the calculated four in-focus position coordinates include coordinates related to the minimum and maximum due to depressions and bulges formed around the recess, the two in-focus positions excluding the coordinates related to the minimum and maximum are excluded. Since automatic focusing can be performed using coordinates obtained by averaging the coordinates, automatic focusing accuracy can be further increased.

  According to the first aspect of the present invention, the position and width of the focusing image area can be arbitrarily set by the focusing image area setting means, so that the automatic focusing accuracy can be improved. It is possible to improve the measurement accuracy of the indentation dimension, and consequently improve the measurement accuracy of the hardness.

  According to the second aspect of the present invention, the in-focus image area is set near the four corners of the depression, and the four in-focus position coordinates are set based on the image information of the set four in-focus image areas. It is possible to calculate and perform automatic focusing based on these four focus position coordinates. As a result, since it is possible to correct the variation of the in-focus position, it is possible to further improve the automatic focusing accuracy, further improve the measurement accuracy of the indentation size, further improve the hardness measurement accuracy, Can bring.

  According to the third aspect of the present invention, automatic focusing is performed using coordinates obtained by averaging two in-focus position coordinates excluding the minimum and maximum coordinates among the four in-focus position coordinates calculated. Therefore, automatic focusing can be performed using coordinates obtained by averaging two in-focus position coordinates excluding these minimum and maximum coordinates. As a result, the automatic focusing accuracy can be further increased.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, the Vickers hardness tester 1 will be described as an example of the hardness tester according to the present invention.

  First, the configuration of the Vickers hardness tester 1 according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view for explaining the overall configuration of the Vickers hardness tester 1, and FIG. 2 is an explanatory diagram for explaining the configuration of the main body 2 of the Vickers hardness tester 1. FIG. 2 is a block diagram showing a functional configuration of the Vickers hardness tester 1.

  The Vickers hardness tester 1 includes a main body 2, a hardness measurement unit 3, an elevating mechanism 4, a sample fixing device 5, an XY stage 6, and the like. The Vickers hardness tester 1 includes a control device 10, a monitor 11, a keyboard 12, a mouse 13, and the like outside the main body 2.

  As shown in FIG. 2, the hardness measuring unit 3 includes a CCD camera 31 that can move in the vertical direction (Z direction in FIG. 2), an AF control mechanism 32, an illumination device 33 that illuminates the surface of the sample S, an indenter 34, The objective lens 35 includes a turret 36 that can be switched between the indenter 34 and the objective lens 35 by rotation.

  The AF control mechanism 32 raises and lowers the CCD camera 31 under the control of the control device 10 to realize an automatic focusing operation, and constitutes an automatic focusing means in the present invention.

  The CCD camera 31 is an image pickup means in the present invention, picks up a predetermined area on the surface of the sample S through the objective lens 35, acquires image information, and outputs it to the control device 10.

  The elevating mechanism 4 is connected to the sample fixing device 5, and the operator operates the handle 4 a to raise and lower the sample fixing device 5 in the vertical direction (Z direction in FIG. 2) to bring the sample S into a predetermined focusing position. To move to.

  The sample fixing device 5 is a device for fixing the sample S, and can be moved in the vertical direction by the elevating mechanism 4 described above. The sample S is detachably fixed to the sample fixing device 5 by a fastening member (not shown).

  The XY stage 6 moves in an XY plane perpendicular to the vertical direction (Z direction in FIG. 2) under the control of the control device 10. The XY stage 6 horizontally moves the sample fixing device 5 arranged on the upper part and the sample S detachably fixed to the sample fixing device 5 in both XY directions, and the sample is moved below the hardness measuring unit 3. Position S.

  As shown in FIG. 3, the control device 10 includes a CPU 10 a that is connected to each unit and integrally controls the entire device, a ROM 10 b that stores a control program for controlling each unit, and various data generated by executing various programs. It has a RAM 10c that functions as a work area for temporary storage.

  The CPU 10a moves the XY stage 6 so that a predetermined area on the surface of the sample S is located directly below the CCD camera 31 by executing an XY stage control program stored in the ROM 10b.

  Further, the CPU 10a executes an autofocus program stored in the ROM 10b, thereby adjusting the light amount of the illumination device 33 based on image information obtained by the CCD camera 31 of the hardness measuring unit 3, and performing AF control. The CCD camera 31 is moved up and down by controlling the mechanism 32 to automatically focus the surface of the sample S. That is, the CPU 10a, the automatic focusing program, and the AF control mechanism 32 are automatic focusing means in the present invention.

  Further, the CPU 10a receives an input signal by operating the keyboard 12 or the mouse 13, and executes an in-focus image area setting program stored in the ROM 10b, whereby an image area (in-focus image for use in automatic focusing) is obtained. The position and area (area) of the (region) can be arbitrarily set. That is, the CPU 10a and the focusing image area setting program are focusing image area setting means in the present invention.

  In addition, the CPU 10a executes a hardness measurement unit control program stored in the ROM 10b, thereby pressing the indenter 34 against the surface of the sample S with a predetermined test force to form a recess or obtained from the CCD camera 31. The diagonal length of the recess is measured based on the image information of the surface of the sample S, and the hardness of the sample S is calculated based on the measured diagonal length of the recess. Furthermore, the image information of the surface of the sample S acquired by the CCD camera 31, the calculation result of the hardness of the sample S, and the like are displayed on the monitor 11.

  The monitor 11 is a display unit that visualizes the image information of the surface of the sample S acquired by the CCD camera 31 and displays the calculation result of the hardness of the sample S. The keyboard 12 and the mouse 13 are input means for an operator to input various setting conditions.

  Next, the hardness measurement operation by the Vickers hardness tester 1 according to the present embodiment will be described with reference to FIGS. FIG. 4 is a flowchart for explaining the hardness measurement operation in the present embodiment.

  First, the user fixes the sample S whose hardness is measured to the sample fixing device 5 (sample fixing step: S1). Then, the CPU 10a of the control device 10 moves the XY stage 6 horizontally by executing an XY stage control program in accordance with an input signal generated by operating the keyboard 12 or the mouse 13, and the surface of the sample S is indented by the hardness measuring unit 3. It arranges in the position which opposes.

  Next, the CPU 10a of the control device 10 executes a hardness measurement unit control program, thereby pressing the indenter 34 of the hardness measurement unit 3 against a predetermined position on the surface of the sample S and applying a predetermined test force for a certain period of time. A recess is formed on the surface of the sample S (recess formation step: S2). Thereafter, the CPU 10a of the control device 10 rotates the turret 36 of the hardness measuring unit 3 and arranges the objective lens 35 above the recess.

  Next, the CPU 10a of the control device 10 executes the hardness measurement unit control program, thereby illuminating the surface of the sample S with the illuminating device 33 and the vicinity of the indentation on the surface of the sample S by the CCD camera 31 through the objective lens 35. A part is imaged and image information is acquired. Then, the acquired image information is displayed on the monitor 11 (image information display step: S3). FIG. 5 shows a state in which the depression K on the surface of the sample S is displayed on the display screen 11 a of the monitor 11.

  Next, the user operates the handle 4a of the elevating mechanism 4 while moving up and down the sample fixing device 5 and the sample S while visually recognizing the display screen 11a of the monitor 11, thereby causing the sample S to move to the objective lens 35 with a predetermined amount. The surface of the sample S is placed at the in-focus position, separated by a distance (manual focusing step: S4).

Next, the user determines whether or not to change the image area used for automatic focusing (focusing image area) (focusing condition determination step: S5). If it is determined in the focusing condition determination step S5 that the focusing image area is not changed, the user uses the default focusing image area without performing an operation for changing the focusing image area. Then, the automatic focusing step S11, the indentation dimension measuring step S12, and the hardness calculating step S13 are sequentially performed. In FIG. 5, the area surrounded by the alternate long and short dash line is the default focusing image area A ₁ .

  In the automatic focusing step S11, the CPU 10a of the control device 10 executes the automatic focusing program, thereby controlling the AF control mechanism 32 based on the image information in the focusing image area to move the CCD camera 31 up and down. And focus on the surface of the sample S.

  After passing through the automatic focusing step S11, the user operates the keyboard 12 and the mouse 13, causes the CPU 10a of the control device 10 to execute the hardness measurement unit control program, and indents the CCD camera 31 of the hardness measurement unit 3. The length of the diagonal line K (see FIG. 5) is automatically measured (indentation dimension automatic measuring step: S12). And CPU10a of the control apparatus 10 calculates the hardness of the sample S from the length of the diagonal line of the measured hollow (hardness calculation process: S13).

  On the other hand, if it is determined in the focusing condition determination step S5 that the focusing image area is to be changed, the user sets the display screen 11a (FIG. 5) of the monitor 11 in order to set the position of the new focusing image area. Reference) The desired position above is designated using the mouse 13. Upon receiving such a designation signal, the CPU 10a of the control device 10 starts a focusing image area setting program to display a new focusing image area at a designated position on the display screen 11a of the monitor 11 (focusing). Focusing image area setting step: S6).

The user can specify the position of the new focusing image area with the mouse 13 and can also operate the keyboard 12 to specify the size (area) of the new focusing image area. The area surrounded by the bold line in FIG. 5 is an example of a new in-focus image area A ₂ set in the in-focus image area setting step S6.

Next, the user determines whether or not to perform a precision automatic focusing process for the purpose of improving the hardness measurement accuracy (precise focusing determination step: S7). In a fine focusing decision step S7, if it is determined not to perform precise automatic focusing process, the user, using the image area A ₂ for focusing set in the focusing image area setting step S6, the automatic focus The focusing step S11, the indentation size automatic measuring step S12, and the hardness calculating step S13 are sequentially performed.

  On the other hand, if it is determined in the precise focus determination step S7 that the precise automatic focus process is to be performed, the user operates the keyboard 12 or the mouse 13 and executes the hardness measurement unit control program by the CPU 10a of the control device 10. Let it run. Then, the position coordinates near the four corners of the depression K (see FIG. 5) of the sample S are acquired by the CCD camera 31 of the hardness measuring unit 3 (position coordinate acquisition step: S8).

Next, the CPU 10a of the control device 10 starts a focusing image area setting program, and sets new focusing image areas in the vicinity of the four corners of the indentation K by referring to the acquired position coordinates ( Precision focusing image area setting step: S9). Four areas surrounded by a broken line in FIG. 5 indicate the new in-focus image area A ₃ set in the fine focus image area setting step S9.

Then, CPU 10a of the controller 10 executes the automatic focusing program, based on the four focusing image information of the image area A ₃ set in the image area setting step S9 for focusing precision focus AF control mechanism 32 is controlled to move the CCD camera 31 up and down to automatically focus on the surface of the sample S (precision automatic focusing step: S10).

In the precise automatic focusing step S10, four in-focus positions corresponding to the image information of the four in-focus image areas A ₃ are calculated, and among these four in-focus position coordinates, the minimum and maximum are related. Automatic focusing is performed using coordinates obtained by averaging two in-focus position coordinates excluding the coordinates. Here, the “coordinates related to the minimum” means in-focus position coordinates that are most distant from the surface of the sample S on the lower side (the lower side in the drawing of FIG. 2). The in-focus position coordinates that are most distant from the surface of the sample S to the upper side (the upper side in the drawing of FIG. 2). The “coordinates related to the minimum” are coordinates resulting from the depression formed around the recess, and the “coordinates related to the maximum” are coordinates resulting from the bulge formed around the recess.

  After the precision automatic focusing step S10, the user operates the keyboard 12 and the mouse 13 to execute the hardness measurement unit control program by the CPU 10a of the control device 10, and the CCD camera 31 of the hardness measurement unit 3 uses the CCD camera 31. The length of the diagonal line of the indentation K is automatically measured (indentation dimension automatic measuring step: S12). And CPU10a of the control apparatus 10 calculates the hardness of the sample S from the length of the diagonal line of the measured hollow (hardness calculation process: S13). The hardness measurement operation is completed through the above process group.

  In the Vickers hardness tester 1 according to the present embodiment, the image area (focusing image area) used for automatic focusing by the focusing image area setting means (the CPU 10a and the focusing image area setting program). The position and width (area) of can be arbitrarily set.

  Therefore, it is possible to set the focusing image area according to the size, shape, etc. of the sample S, or to set the focusing image area so as to avoid the depression or bulge formed around the recess K. it can. As a result, the automatic focusing accuracy can be increased, and the measurement accuracy of the diagonal length of the dent can be improved, and consequently the measurement accuracy of the hardness can be improved.

Further, in the Vickers hardness tester 1 according to the present embodiment, the focusing image area A ₃ can be set in the vicinity of the four corners of the recess K, and the four set focusing image areas are set. calculating a four-focus position based on the image information of a _3, of these four focus position coordinates, using the averaged coordinate two-focus position coordinates except the coordinates of the minimum and maximum Automatic focusing can be performed.

  Therefore, even when the calculated four in-focus position coordinates include coordinates related to the minimum and maximum due to depressions and bulges formed around the recess, the two in-focus positions excluding the coordinates related to the minimum and maximum are excluded. Since automatic focusing can be performed using coordinates obtained by averaging the coordinates, the automatic focusing accuracy can be further improved. As a result, it is possible to further improve the measurement accuracy of the diagonal length of the dent and further improve the accuracy of measurement of the hardness.

  In the present embodiment, an example in which the present invention is applied to the Vickers hardness tester 1 is shown. However, another hardness test in which a recess is formed on the surface of the sample and the hardness is measured according to the size of the recess. The present invention can also be applied to a machine (for example, a Brinell hardness tester or a Knoop hardness tester).

  Further, in the present embodiment, in the precise automatic focusing step S10, automatic focusing is performed using coordinates obtained by averaging two focusing position coordinates excluding the minimum and maximum coordinates among the four focusing position coordinates. Although an example of performing focusing has been shown, automatic focusing can also be performed using coordinates obtained by averaging four focusing position coordinates.

  In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as the object of the present invention can be achieved.

1 is a perspective view showing an overall configuration of a Vickers hardness tester according to an embodiment of the present invention. It is explanatory drawing for demonstrating the structure of the main body of the Vickers hardness tester shown in FIG. It is a block diagram for demonstrating the functional structure of the Vickers hardness tester shown in FIG. It is a flowchart for demonstrating the hardness measurement operation | movement of the Vickers hardness tester shown in FIG. It is a figure which shows the state which displayed on the monitor the image information of the surface of the sample acquired by the CCD camera of the Vickers hardness tester shown in FIG. It is a figure which shows the state which displayed on the monitor the image information of the surface of the sample acquired with the CCD camera of the conventional Vickers hardness tester.

Explanation of symbols

1 Vickers hardness tester 10a CPU (automatic focusing means, focusing image area setting means)
31 CCD camera (imaging means)
32 AF control mechanism (automatic focusing means)
34 Indenter A ₂ , A ₃ Focusing image area K Recess S Sample

Claims (3)

In a hardness tester that calculates the hardness of the sample by forming a recess on the surface of a predetermined sample using an indenter and measuring the size of the recess,
Imaging means for imaging the surface of the sample and obtaining predetermined image information;
Based on the image information acquired by the imaging means, automatic focusing means for performing automatic focusing when measuring the size of the recess,
An in-focus image area setting means for enabling setting of an in-focus image area which is an image area used for the automatic focusing;
A hardness tester comprising: The planar shape of the indentation is substantially rectangular,
The focusing image area setting means includes:
Set the focusing image area near the four corners of the indentation,
The automatic focusing means includes
Four focus position coordinates are calculated based on the image information of the four focus image areas set in the vicinity of the four corners of the depression, and automatic focusing is performed based on the four focus position coordinates. The hardness tester according to claim 1, wherein: The automatic focusing means includes
3. The hard focus according to claim 2, wherein automatic focusing is performed using a coordinate obtained by averaging two focus position coordinates excluding the minimum and maximum coordinates among the four focus position coordinates. Testing machine.

Images