IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
UP-0656458
(2007-01-23)
|
등록번호 |
US-7545512
(2009-07-01)
|
우선권정보 |
KR-10-2006-0008479(2006-01-26); KR-10-2006-0008480(2006-01-26) |
발명자
/ 주소 |
- Kim, Min Young
- Kim, Hee Tae
- Yoo, Byung Min
- Han, Se Hyun
- Lee, Seung Jun
|
출원인 / 주소 |
- Koh Young Technology Inc.
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
3 인용 특허 :
4 |
초록
▼
A method of measuring a 3D shape includes the steps of measuring a brightness of a first illumination source 41a, measuring a phase-to-height conversion factor, measuring a 3D shape of a circuit board 62 according to the normal inspection mode, and determining whether bare board information about th
A method of measuring a 3D shape includes the steps of measuring a brightness of a first illumination source 41a, measuring a phase-to-height conversion factor, measuring a 3D shape of a circuit board 62 according to the normal inspection mode, and determining whether bare board information about the circuit board 62 is included. If the information is not included, performing bare board teaching to acquire the information. Then, the 3D shape of target objects on the circuit board 62 are measured, when the bare board information is included or bare board teaching information is generated. Next, the circuit board 62 is analyzed to determine if it is normal or abnormal by using 3D shape information.
대표청구항
▼
What is claimed is: 1. A method of measuring a 3 dimensional (3D) image of a circuit board, the method comprising the steps of: establishing a correspondence between illumination adjustment command values and a brightness of a first illumination source by controlling a module control unit and an im
What is claimed is: 1. A method of measuring a 3 dimensional (3D) image of a circuit board, the method comprising the steps of: establishing a correspondence between illumination adjustment command values and a brightness of a first illumination source by controlling a module control unit and an image acquisition unit through a central control unit for each of a plurality of illumination adjustment command values; establishing a phase-to-height conversion factor by controlling the module control unit and the image acquisition unit to obtain image data from a plurality of images captured by a camera coupled to the image acquisition unit; determining whether a measurement is to be performed in a normal inspection mode or a teaching mode; in the normal inspection mode, measuring a 3D shape of target objects on the circuit board by controlling the module control unit and the image acquisition unit through the central control unit; in the teaching mode, establishing height data for a bare circuit board by controlling the module control unit and the image acquisition unit through the central control unit; following establishment of the height data for a bare circuit board, measuring the 3D shape of target objects on the circuit board by controlling the module control unit and the image acquisition unit through the central control unit; and analyzing the measured 3D shape of target objects on the circuit board in the central control unit whether the 3D shape of the target objects is one of normal or abnormal. 2. The method of claim 1, wherein the step of establishing a correspondence between illumination adjustment command values and a brightness of the first illumination source comprises the steps of: adjusting a brightness of the first illumination source by an illumination controller of the module control unit for each of a plurality of illumination adjustment command values output by the central control unit; acquiring a plurality of images of a calibration target from the camera coupled to the image acquisition unit for each illumination adjustment command value, the plurality of images being captured in correspondence with projection of a grating onto the calibration target and successively moved relative to the calibration target an N number of times and capturing an image thereof via the camera for each movement; receiving the acquired images via an interface board and an image processing board of the central control unit and then performing an averaging process with respect to the received images for each illumination adjustment command value, and calculating an average image for each illumination adjustment command value; setting a representative brightness value based on the calculated average image as an illumination brightness for each corresponding illumination adjustment command value; and generating an illumination index table defining the illumination brightness corresponding to each illumination adjustment command value. 3. The method of claim 2, wherein the step of adjusting of a brightness of the first illumination source comprises the steps of: driving an X-Y table to move the calibration target to a measurement location; switching on the first illumination source when the calibration target has been moved to the measurement location; setting a range of the illumination adjustment command values; and adjusting the brightness of the first illumination source according to each illumination adjustment command value by controlling the illumination controller. 4. The method of claim 2, further comprising the steps of: determining that a plurality of first illumination sources are provided; switching off the first illumination source for which a correspondence between the illumination adjustment command values and the brightness was first established and switching on a remaining one of the plurality of first illumination sources; comparing an illumination brightness corresponding to the illumination adjustment command values for the first illumination source for which a correspondence between the illumination adjustment command values and the brightness was first established with an illumination brightness corresponding to the illumination adjustment command values of the remaining first illumination source, selecting a lower illumination brightness therebetween as a brightness of a total illumination system for each illumination adjustment command value, and calculating a new illumination adjustment command value of each first illumination source corresponding to a selected illumination brightness of the total illumination system; and redefining each of the illumination adjustment command values of the plurality of first illumination sources to correspond to the respective selected illumination brightness of the total illumination system. 5. The method of claim 1, wherein the step of establishing a phase-to-height conversion factor comprises the steps of: a. adjusting the brightness of the first illumination source according to a selected illumination adjustment command value; b. setting a plane surface of a calibration target as an inspection area; c. acquiring images of the plane surface of the calibration target from the acquisition unit, the images including a grating pattern projected onto the plane surface, the images being acquired concurrently with successively moving the projected grating pattern relative to the plane surface an N number of times; d. generating a phase map of the plane surface from the acquired images using an N-bucket algorithm, and storing the phase map as a phase map of a first reference surface; e. setting a stepped surface difference of the calibration target as the inspection area; f. acquiring images of the stepped surface difference of the calibration target from the acquisition unit, the images including the grating pattern projected onto the stepped surface difference, the images being acquired concurrently with successively moving the projected grating pattern relative to the plane surface the N number of times; g. generating a phase map of the stepped surface difference from the acquired images of the stepped surface difference using the N-bucket algorithm; and h. calculating a phase-to-height conversion factor of each pixel of the acquired images of the stepped surface difference using the generated phase maps, and storing the calculated phase-to-height conversion factor. 6. The method of claim 5, wherein the step of adjusting of the brightness of the first illumination source comprises the steps of: moving the calibration target to the measurement location by a table controller driving a table moving device to displace an X-Y table; switching on the first illumination source; selecting the illumination adjustment command value; and adjusting the brightness of the first illumination source to the illumination brightness corresponding to the selected illumination adjustment command value. 7. The method of claim 5, further comprising the steps of: determining that a plurality of first illumination sources are provided; and repeating steps a-h for the remaining first illumination source. 8. The method of claim 1, further comprising the steps of: moving the circuit board to a measurement location by displacing an X-Y table; switching on a second illumination source by controlling an illumination controller; calculating location information and storing image information with respect to a particular part of the circuit board being imaged by the camera; searching a database for bare circuit board information which is identical to the calculated location information and image information of the particular part of the board being imaged; and determining bare circuit board information being included in the database responsive to the calculated location information and image information matching location information and image information stored in the database. 9. The method of claim 5, wherein the step of measuring the 3D shape of target objects on the circuit board comprises the steps of: moving the circuit board to a measurement location by driving a table moving device to displace an X-Y table; adjusting the brightness of the first illumination source according to a selected illumination adjustment command value by controlling an illumination controller; generating a phase map of the circuit board and calculating a relative height phase with respect to a first reference surface by controlling the module control unit and the image acquisition unit; and calculating a phase histogram using the calculated relative height phase with respect to the first reference surface and calculating the 3D shape of target objects on the board using the calculated phase histogram. 10. The method of claim 9, wherein the steps of calculating a relative height phase, calculating a phase histogram, and calculating of the 3D shape of target objects on the board further comprise the steps of: calculating the phase histogram using the relative height phase with respect to the first reference surface subsequent to calculating the relative height phase with respect to the first reference surface of the circuit board in accordance with the projected grating pattern from the first illumination source; separating a second reference surface and a solder from the calculated phase histogram and calculating a centroid of each of the second reference surface and the solder; calculating a representative height of the solder by using the centroid of the second reference surface and the centroid of the solder; and calculating a volume, a height distribution, and an positional offset of the solder using the calculated representative height of the solder. 11. The method of claim 9, wherein the steps of calculating a relative height phase, calculating a phase histogram, and calculating of the 3D shape of target objects on the board further comprise the steps of: calculating and storing a combined height phase where noise is removed from the relative height phase with respect to the first reference surface of the circuit board when a plurality of first illumination sources are provided, the combined height phase being a combination of the calculated relative height phase with respect to the first reference surface of the circuit board in accordance with the projected grating pattern from one of the plurality of first illumination sources and the calculated relative height phase with respect to the first reference surface of the circuit board in accordance with the projected grating pattern from the remaining first illumination source; calculating the phase histogram by using the stored combined height phase; separating a second reference surface and a solder from the calculated phase histogram and calculating a centroid of each of the second reference surface and the solder; calculating a representative height of the solder by using the centroid of the second reference surface and the centroid of the solder; and calculating a volume, a height distribution, and an positional offset of the solder by using the calculated representative height of the solder. 12. The method of claim 1, wherein the step of establishing height data for a bare circuit board in the teaching mode comprises the steps of: moving the bare circuit board to a measurement location, the bare circuit board being disposed on an X-Y table displaced by a table moving device driven by a table controller; adjusting the brightness of the first illumination source according to a selected adjustment command value by controlling the illumination controller through the central control unit; generating a phase map of the bare circuit board and calculating a relative height phase with respect to a first reference surface by controlling the module control unit and the image acquisition unit following adjustment of the brightness of the first illumination source; and storing location information and image information about a particular part of the bare circuit board, the image information being an image reflected from the bare circuit board using illumination generated from the second illumination source and captured by the camera. 13. The method of claim 12, wherein the step of storing of the location information comprises the steps of: storing the relative height phase with respect to the first reference surface as height phase information of the bare circuit board; determining whether height data has been establish for all areas of the bare circuit board in the teaching mode following storage of the height phase information; switching off the first illumination source and switching on the second illumination source by controlling the illumination controller of the module control unit subsequent to height data having been establish for all areas of the bare circuit board; and acquiring and storing an image of a particular part of the bare circuit board via the camera, and calculating the location information about the particular part of the bare circuit board by using the stored image and the height phase information, the calculated location information being stored as the bare circuit board information in a database. 14. The method of claim 12, wherein the step of storing of the location information comprises steps of: calculating a combined height phase where noise is removed from the relative height phase with respect to the first reference surface of the circuit board when a plurality of first illumination sources are provided, the combined height phase being a combination of the calculated relative height phase with respect to the first reference surface of the bare circuit board using one of the plurality of first illumination sources and the calculated relative height phase with respect to the first reference surface of the bare circuit board using the remaining first illumination source; storing the combined height phase as the height phase information; determining whether height data has been establish for all areas of the bare circuit board in the teaching mode following storage of the height phase information; switching off the first illumination source and switching on the second illumination source by controlling the illumination controller of the module control unit subsequent to height data having been established for all areas of the bare circuit board; and acquiring and storing an image of a particular part of the bare circuit board via the camera, and calculating the location information about the particular part of the bare circuit board by using the stored image and the height phase information, the calculated location information being stored as the bare circuit board information in a database. 15. The method of claim 1, wherein the step of measuring a 3D shape of target objects on the circuit board comprises the steps of: reading a database for bare circuit board information corresponding to the circuit board; moving the circuit board disposed on an X-Y table to a measurement location by using a table controller to drive a table moving device and thereby displace the X-Y table; adjusting a brightness of the first illumination source according to a selected illumination adjustment command value; generating a phase map of the circuit board and calculating a relative height phase with respect to a first reference surface by controlling the module control unit and the image acquisition unit following adjustment of the brightness of the first illumination source; and calculating a phase histogram using the relative height phase with respect to the first reference surface, and measuring the 3D shape of target objects on the board using the calculated phase histogram. 16. The method of claim 15, wherein the steps of calculating of the phase histogram and the measuring of the 3D shape of target objects on the circuit board further comprise the steps of: storing the relative height phase with respect to the first reference surface as height phase information of the circuit board, the calculated relative height phase being with respect to the first reference surface of the circuit board in accordance with a projected grating pattern from the first illumination source; separating height phase information of a solder by using the height phase information of the circuit board and the height phase information of the bare circuit board stored in the database; and calculating actual height information from the separated height phase information of the solder, and calculating a volume, a height distribution, and a positional offset of the solder. 17. The method of claim 15, wherein the step of measuring of the 3D shape of target objects on the circuit board further comprises the steps of: calculating a combined height phase where noise is removed from the relative height phase with respect to the first reference surface of the circuit board when a plurality of first illumination sources are provided, the combined height phase being a combination of the calculated relative height phase with respect to the first reference surface of the circuit board using one of the plurality of first illumination sources and the calculated relative height phase with respect to the first reference surface of the circuit board using the remaining first illumination source; storing the combined height phase as height phase information; separating height phase information of a solder by using the height phase information of the circuit board and height phase information of the bare circuit board stored in the database; and calculating actual height information from the height phase information of the solder and calculating a volume, a height distribution, and a positional offset of the solder. 18. The method of claim 9, 12, or 15, wherein the step of adjusting the brightness of the first illumination source comprises the steps of: switching on the first illumination source by controlling the illumination controller; selecting an illumination adjustment command value; and adjusting the brightness of the first illumination source to an illumination brightness according to the selected illumination adjustment command value by controlling the illumination controller. 19. The method of claim 9, 12, or 15, wherein the step of adjusting the brightness of the first illumination source comprises the steps of: determining whether one of a plurality of first illumination sources is selected; switching on the selected first illumination source by controlling the illumination controller; selecting an illumination adjustment command value; adjusting the selected first illumination source to an illumination brightness according to the selected illumination adjustment command value by controlling the illumination controller; switching on a remaining first illumination source by controlling the illumination controller; selecting the illumination adjustment command value; and adjusting the remaining first illumination source to the illumination brightness according to the selected illumination adjustment command value by controlling the illumination controller. 20. The method of claim 9, 12, or 15, wherein the step of calculating the relative height phase comprises the steps of: acquiring images responsive to moving a grating device an N number of times, and projecting a grating pattern from the first illumination source in correspondence with each movement; expanding an inspection area to repeat the acquiring of the images; calculating and storing the phase map using an N-bucket algorithm; and calculating the relative height phase with respect to the first reference surface of the circuit board in a corresponding inspection location using a difference between the phase map of the first reference surface and the phase map stored in the central control unit. 21. The method of claim 9, 12, or 15, wherein the step of calculating the relative height phase comprises the steps of: acquiring images responsive to moving a grating device an N number of times, and projecting a grating pattern from one of a plurality of first illumination sources in correspondence with each movement; expanding an inspection area to repeat the acquiring of the images; calculating and storing the phase map by using an N-bucket algorithm; calculating the relative height phase with respect to the first reference surface in a corresponding inspection location by using a difference between the phase map of the first reference surface and the stored phase map; acquiring images responsive to moving the grating device the N number of times, and projecting the grating pattern from the remaining first illumination source; and repeating the expanding of the inspection area, the calculating and storing of the phase map, and the calculating of the relative height phase using the N-bucket algorithm.
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