JP5415791B2 - Imaging device and electronic circuit component mounting machine - Google Patents

Description

  The present invention relates to an imaging apparatus including a CMOS image sensor, and an electronic circuit component mounting machine including the imaging apparatus.

  In Patent Document 1 below, imaging is performed in a light-shielded state by an imaging device including a CCD image sensor, and fixed noise caused by dark current is obtained for each unit cell of the CCD image sensor and stored in a memory. A technique is described in which fixed noise is subtracted and removed from imaging data corresponding to each pixel obtained during imaging in a light-shielded state. Since fixed noise changes depending on the imaging conditions such as the temperature of the CCD image sensor at the time of imaging, the fixed noise is determined based on the difference in imaging conditions between imaging for acquiring fixed noise and imaging in a non-shielded state. Corrected corrected fixed noise is used. The temperature of the CCD image sensor is detected by a temperature sensor.

  Patent Document 2 below describes a technique for estimating the temperature of an image sensor based on the dark current of the CCD image sensor. Further, it is described that an optical black portion is used for detecting a dark current, and that processing of imaging output acquired by a CCD image sensor is changed based on an estimated temperature. As an example of the change, it is described that the amplification gain of the analog signal from the CCD image sensor is changed and that the fixed pattern noise of the CCD image sensor is reduced.

JP 2006-345458 A JP2005-130045

  In view of the above circumstances, the present invention uses a CMOS image sensor as an imaging device to obtain an imaging device that is more practical than before, such as reduction of fixed noise, and mounting an electronic circuit component including the imaging device. It was made as an issue to get the opportunity.

According to the present invention, (a) a CMOS image sensor in which a unit cell existence area, which is an area where a plurality of unit cells each having an amplifier and perform photoelectric conversion, includes an imaging area and an optical black area, and (b) An imaging output acquisition unit for acquiring an imaging output by causing the CMOS image sensor to perform imaging of an imaging target; and (c) causing the CMOS image sensor to perform imaging in a state where light incident on the CMOS image sensor is uniform. A fixed pattern noise information acquisition unit for acquiring information on fixed pattern noise generated due to variations in amplification factors of amplifiers of a plurality of unit cells in the imaging area of the CMOS image sensor, and (d) the fixed pattern noise information Either fixed pattern noise information acquired by the acquisition unit or information for correcting the fixed pattern noise A fixed pattern noise related information storage unit for storing fixed pattern noise related information, and (e) acquired by an imaging output acquisition unit based on the fixed pattern noise related information stored in the fixed pattern noise related information storage unit Fixed pattern noise reduction unit that reduces fixed pattern noise in the captured imaging output, and (f) one of the output patterns from the optical black area when the imaging output acquisition is performed by the imaging output acquisition unit as a reference output A reference output pattern storage unit that stores the pattern, and (g) an output obtained from the optical black area when the imaging output acquisition unit acquires the imaging output after storing the reference output pattern in the reference output pattern storage unit The difference state between the current output pattern and the reference output pattern is more than the set state. The reference output pattern update unit that updates the reference output pattern by replacing the current output pattern with the reference output pattern, and (h) when the reference output pattern is updated by the reference output pattern update unit, An imaging apparatus including a fixed pattern noise related information update unit that operates a fixed pattern noise information acquisition unit to acquire new fixed pattern noise information and updates the fixed pattern noise related information in the fixed pattern noise related information storage unit. can get.
Further, according to the present invention, (i) a substrate holding device that holds a circuit board, (ii) a component supply device that supplies an electronic circuit component to be mounted on a circuit board held by the substrate holding device, and (iii) ) From the component supply device, an electronic circuit component is received by a component holder and mounted on a circuit board held by the substrate holding device; and (iv) an image of the electronic circuit component held by the component holder is taken. A component imaging device; and (v) an image processing device that processes an imaging output representing an image of an electronic circuit component imaged by the component imaging device to obtain a holding position error of the electronic circuit component by the component holder; vi) An electronic circuit component mounting machine including a mounting control unit that controls the mounting apparatus so as to correct the holding position error acquired by the image processing apparatus and mount it on the circuit board held by the board holding apparatus. Because Those goods imaging device is constituted by an imaging apparatus according to the present invention is obtained.

An image pickup apparatus according to the present invention uses a CMOS image sensor as an image pickup element, and a unit cell existence area, which is an area where unit cells of the CMOS image sensor exist, is optical black together with an image pickup area for picking up an object. It is supposed to include the area. The imaging apparatus according to the present invention includes (a) a reference output pattern storage that stores, as a reference output pattern, one of the output patterns from the optical black area when the imaging output acquisition unit acquires the imaging output. And (b) the current output pattern and the reference that are output patterns obtained from the optical black area when the imaging output acquisition unit acquires the imaging output after the reference output pattern is stored in the reference output pattern storage unit. A reference output pattern update unit that updates the reference output pattern by replacing the current output pattern with the reference output pattern when the difference state from the output pattern exceeds the set state; and (c) the reference output pattern update. When the reference output pattern is updated by the unit, the fixed pattern noise information acquisition unit is activated to generate a new fixed pattern. To obtain information N'noizu, it is intended to include fixed pattern noise related information updating unit for updating the fixed pattern noise related information of the fixed pattern noise related information storage unit.
In general, the temperature of a CMOS image sensor does not change so rapidly. Therefore, it does not occur so frequently that the difference state between the current output pattern and the reference output pattern exceeds the set state. Therefore, in the imaging apparatus according to the present invention, imaging for updating the fixed pattern noise related information by the fixed pattern noise related information updating unit is not performed so frequently, and the fixed pattern noise information is obtained every time the imaging output acquisition unit is operated. Compared with the case where the acquisition unit is operated, the time required for reducing the fixed pattern noise can be shortened.
Further, according to the electronic circuit component mounting machine according to the present invention, in an environment where a relatively large temperature change is likely to occur, an electronic circuit using a component holder is used while using an imaging device including a relatively inexpensive CMOS image sensor. It is possible to acquire the component holding position error with high accuracy and mount the component on the circuit board with high accuracy.

Aspects of the Invention

The following invention which is considered claimable (hereinafter referred to as "claimable invention". Claimable invention, to not "present invention" a is an invention described in the scope of the billed " Examples of subordinate concept inventions of the present invention ”, superordinate concepts of the present invention, or inventions of other concepts may be included. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the combinations of the constituent elements constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, the prior art, and the like. The added aspect and the aspect in which the constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

(1) a CMOS image sensor in which each of a plurality of unit cells formed in an imaging area and performing photoelectric conversion each has an amplifier;
An imaging output acquisition unit that acquires an imaging output by causing the CMOS image sensor to perform imaging of an imaging target;
In the state where the temperature of the CMOS image sensor is equal to the time when the imaging output acquisition unit acquires the imaging output and the light incident state to the CMOS image sensor is uniform, the plurality of unit cells of the CMOS image sensor A fixed pattern noise information acquisition unit for acquiring information of fixed pattern noise of the imaging area caused by variation in amplification factor of the amplifier;
An imaging apparatus comprising: a fixed pattern noise reduction unit that reduces fixed pattern noise in the imaging output acquired by the imaging output acquisition unit based on information on the fixed pattern noise acquired by the fixed pattern noise information acquisition unit.
In this specification, the “imaging target” may be the entire object or a part of the object. The former is referred to as an imaging object, and the latter is referred to as an imaging target part.
The “imaging output” includes an imaging signal that is an analog signal output from the CMOS image sensor and imaging data obtained by digitizing the imaging signal.
The “fixed pattern noise information acquisition unit” may be one that reads and acquires fixed pattern noise related information from the “fixed pattern noise related information storage unit” in the next section. As described above, the CMOS image sensor may perform imaging in a state where the light incident state on the CMOS image sensor is uniform, and information on fixed pattern noise may be actually acquired. The invention according to this section is a superordinate invention of the invention according to paragraph (2) and the invention according to paragraph (9).
In the above-mentioned “state where the light incident state on the CMOS image sensor is uniform”, uniform light is emitted, for example, when imaging a uniform light emitter that emits light of uniform brightness from the light emitting surface. A state where light is incident on the CMOS image sensor and a light shielding state where no light is incident on the CMOS image sensor are included. The former is used when acquiring information on the so-called black spot fixed pattern noise, in which a darker point appears in a bright image, and the latter is a so-called white spot or white spot in which a brighter point appears in a dark image. It works when acquiring information about fixed pattern noise.
Furthermore, “the temperatures of the CMOS image sensors are equal” means that the temperatures are equal to such an extent that the fixed pattern noise in the imaging area of the CMOS image sensor can be regarded as the same. For example, the temperature difference is 10 ° C. or less. If it is 5 ° C. or less, or 2.5 ° C. or less, it can be said that the temperature of the CMOS image sensor is the same when the imaging output is acquired and when the fixed pattern noise is acquired.
According to the invention of this section, the fixed pattern noise that occurs due to the variation in the amplification factor of each amplifier of the plurality of unit cells of the CMOS image sensor and changes as the temperature of the CMOS image sensor changes is good. Thus, an imaging apparatus capable of obtaining a favorable imaging output regardless of changes in the environmental temperature while using an inexpensive CMOS image sensor can be obtained.
(2) a CMOS image sensor in which each of a plurality of unit cells formed in an imaging area and each performs photoelectric conversion has an amplifier;
An imaging output acquisition unit that acquires an imaging output by causing the CMOS image sensor to perform imaging of an imaging target;
Information on fixed pattern noise of the imaging area caused by variation in amplification factor of the amplifier of the plurality of unit cells of the CMOS image sensor at each of a plurality of temperatures of the CMOS image sensor, and the fixed pattern noise A fixed pattern noise-related information storage unit that stores a plurality of types of fixed pattern noise-related information corresponding to each of the temperatures;
A sensor temperature acquisition unit for acquiring the temperature of the CMOS image sensor when the imaging target is imaged by the CMOS image sensor;
The imaging output acquired by the imaging output acquisition unit based on the temperature acquired by the sensor temperature acquisition unit and the plural types of fixed pattern noise related information stored in the fixed pattern noise related information storage unit A fixed pattern noise reduction unit that reduces fixed pattern noise in the correction by correction.
The reduction of the fixed pattern noise may be performed for all unit cells, or may be performed only for those having a particularly large degree of deviation from the average level as in the next section.
(3) The fixed pattern noise related information storage unit is associated with each of a plurality of temperatures of the CMOS image sensor as the plurality of types of fixed pattern noise related information. On the other hand, among the plurality of unit cells, (i) the degree of deviation of the deviation unit cell that is a unit cell in which the amplification factor of the amplifier deviates from the average value of the amplification factors of the plurality of unit cells by a set value or more. A plurality of types of deviation pattern noise that is a set of any one of deviation data that represents data and (ii) correction data that is data for correcting the deviation, and (B) information on the position of the deviation unit cell The imaging device according to (2), including a deviation pattern noise related data storage unit storing related data.
In the imaging apparatus according to this section, (A) a set of one of deviation data and correction data for a deviation unit cell among a plurality of unit cells, and (B) information on a position of the deviation unit cell. A plurality of types of deviation pattern noise related data are associated with each of a plurality of temperatures and stored in the deviation pattern noise related data storage unit, and the fixed pattern noise reduction unit includes the deviation pattern noise related data. Based on this, the fixed pattern noise is corrected. The fixed pattern noise is corrected for the deviation unit cell, but is not corrected for the non-deviation unit cell, so that the fixed pattern noise can be effectively reduced in a short time.
As the “information on the position of the unit cell”, the coordinate value of the unit cell and the address value of the memory space in which the imaging data is stored are suitable.
(4) The deviation pattern noise related data storage unit stores, as the deviation data, a value obtained by dividing the imaging output from each of the deviation unit cells by the average value of the imaging outputs from the plurality of unit cells. The imaging device according to (2) or (3).
According to the feature described in this section, the degree of deviation of the deviation unit cell can be expressed simply and accurately. Further, in order to correct the deviation, the reciprocal of the stored value may be multiplied by the data of the deviation unit cell, so that the deviation can be corrected easily.
Since the imaging output from each unit cell in a uniform light incident state can be considered to be proportional to the amplification factor of the amplifier of each unit cell, the imaging output from each deviation unit cell can be captured from a plurality of unit cells. The value divided by the average output value can be considered as a value obtained by dividing the amplification factor of each deviation unit cell by the average value of the amplification factors of a plurality of unit cells.
(5) The deviation pattern noise related data storage unit stores, as the correction data, the reciprocal of a value obtained by dividing the imaging output from each of the deviation unit cells by the average value of the imaging outputs from the plurality of unit cells. The imaging device according to (2) or (3).
The deviation can be corrected by applying correction data to the imaging output of each deviation unit cell.
(6) The unit cell existence area, which is an area where the unit cell of the CMOS image sensor exists, includes an optical black area together with the imaging area, and the sensor temperature acquisition unit includes:
A reference output pattern storage unit that stores an output pattern of the optical black area corresponding to the plurality of temperatures of the CMOS image sensor as a plurality of types of reference output patterns in association with each of a plurality of temperatures;
Similarity between the current output pattern that is the output pattern of the optical black area at the time of acquisition of the imaging output by the imaging output acquisition unit and each of the plurality of types of reference output patterns stored in the reference output pattern storage unit The imaging device according to any one of (2) to (5), further including: a sensor temperature estimation unit that estimates a temperature of the CMOS image sensor at the time of imaging of the imaging target.
Since the average value of the output from the optical black area changes corresponding to the temperature of the CMOS image sensor, this average value can also be used to estimate the sensor temperature.
However, there is a possibility that a deviation unit cell also exists in the unit cells in the optical black area, and the probability increases as the number of unit cells belonging to the optical black area increases. Even if the unit cell is not as large as the departure unit cell, the amplification factor of the amplifier of each unit cell varies, and the output value for each unit cell differs based on the variation, and the difference is the temperature of the CMOS image sensor. It changes with changes. The output pattern of the optical black area has more information about the temperature of the CMOS image sensor than the average value of the output. Therefore, it is more dependent on the similarity of the output pattern than the average value of the CMOS image sensor than the average value of the output. The reliability of the temperature estimation result is high.
There are various methods for estimating the temperature of the CMOS image sensor based on the similarity of the output pattern of the optical black area. For example, taking the difference between the current output pattern obtained at the time of acquiring the imaging output by the imaging output acquisition unit and each of the plurality of types of reference output patterns stored in association with each of the temperature changing stepwise, It can be estimated that the temperature corresponding to the memory output pattern having the smallest absolute value of the integrated value of the difference is the temperature of the CMOS image sensor. This estimation means is an example of the estimation means in the imaging device described in the next section, and has an advantage that the temperature can be easily estimated.
If two memory output patterns with a small absolute value of the “difference integral value” are selected, it is normal that one integral value is positive and the other integral value is negative. Based on the ratio, the intermediate temperature between the two temperatures corresponding to the two stored output patterns can be estimated as the temperature of the CMOS image sensor, and the temperature can be estimated using a more complicated statistical method. Can also be done.
(7) The sensor temperature estimation unit is most similar to the current output pattern when the imaging target is imaged, among a plurality of types of reference output patterns stored in the reference output pattern storage unit. The imaging apparatus according to item (6), wherein the temperature associated with the imaging target is estimated as a temperature of the CMOS image sensor when the imaging target is imaged.
(8) The fixed pattern noise reduction unit corrects the fixed pattern noise in the imaging data after the imaging output from the imaging area at the time of imaging of the imaging target is digitized into imaging data. The imaging device according to any one of (1) to (7).
The feature of this section is particularly effective when employed in combination with the feature of the above item (3), and can effectively shorten the time required to reduce fixed pattern noise.
(9) a CMOS image sensor in which each of a plurality of unit cells formed in an imaging area and performing photoelectric conversion each has an amplifier;
An imaging output acquisition unit that acquires an imaging output by causing the CMOS image sensor to perform imaging of an imaging target;
The CMOS image sensor performs imaging in a state where the light incident state on the CMOS image sensor is uniform within a preset time range with respect to the acquisition time of the imaging output by the imaging output acquisition unit, and the CMOS A fixed pattern noise information acquisition unit for acquiring information of fixed pattern noise generated due to variations in amplification factors of the amplifiers of the plurality of unit cells in the imaging area of the image sensor;
An imaging apparatus comprising: a fixed pattern noise reduction unit that reduces fixed pattern noise in the imaging output acquired by the imaging output acquisition unit based on information on the fixed pattern noise acquired by the fixed pattern noise information acquisition unit.
The above-mentioned “preset time range” can be said to be the time when the temperature of the CMOS image sensor is equal when the imaging output acquisition unit acquires the imaging output and when the fixed pattern noise information acquisition unit acquires the fixed pattern noise information. If the range is set, the condition for the fixed pattern noise information acquisition unit in the item (1) is that the temperature of the CMOS image sensor is equal to that when the imaging output acquisition unit acquires the imaging output. It is filled.
A mode in which imaging for acquisition of fixed pattern noise by the fixed pattern noise information acquisition unit is performed immediately before or after imaging for acquisition of imaging output by the imaging output acquisition unit is typical of the imaging device of this section It is an aspect.
The features described in the items (3) to (5) and (8) are applicable to the invention according to this item.
(10) Further, fixed pattern noise that stores fixed pattern noise related information that is either information of the fixed pattern noise acquired by the fixed pattern noise information acquisition unit and information for correcting the fixed pattern noise. Including a related information storage unit, wherein the fixed pattern noise reduction unit reads out the fixed pattern noise related information from the fixed pattern noise related information storage unit, and acquires it by the imaging output acquisition unit based on the read out fixed pattern noise related information The imaging apparatus according to item (9), wherein fixed pattern noise in the imaged output is reduced.
(11) a CMOS image sensor in which each of a plurality of unit cells formed in an imaging area and performing photoelectric conversion each has an amplifier;
An imaging output acquisition unit that acquires an imaging output by causing the CMOS image sensor to perform imaging of an imaging target;
Due to variations in amplification factors of the amplifiers of the plurality of unit cells in the imaging area of the CMOS image sensor, the CMOS image sensor is caused to perform imaging in a state where light incident on the CMOS image sensor is uniform. Fixed pattern noise information acquisition unit for acquiring information of fixed pattern noise generated by
A fixed pattern noise related information storage unit that stores fixed pattern noise related information that is either the fixed pattern noise information acquired by the fixed pattern noise information acquisition unit or information for correcting the fixed pattern noise. When,
A fixed pattern noise reduction unit that reduces fixed pattern noise in the imaging output acquired by the imaging output acquisition unit based on the fixed pattern noise related information stored in the fixed pattern noise related information storage unit, and And the unit cell existence area which is an area where the unit cell of the CMOS image sensor exists includes an optical black area together with the imaging area, and the imaging apparatus further includes:
A reference output pattern storage unit that stores one of the output patterns from the optical black area when the imaging output is acquired by the imaging output acquisition unit as a reference output pattern;
After the reference output pattern is stored in the reference output pattern storage unit, the difference state between the current output pattern and the reference output pattern obtained when the imaging output acquisition unit acquires the imaging output is greater than or equal to the set state A reference output pattern update unit that updates the reference output pattern by replacing the current output pattern with the reference output pattern,
When the reference pattern is updated by the reference pattern update unit, the fixed pattern noise information acquisition unit is activated to acquire new fixed pattern noise information, and the fixed pattern noise related information storage unit stores the fixed pattern noise related information. An imaging device comprising: a fixed pattern noise related information update unit that updates information.
In general, the temperature of a CMOS image sensor does not change so rapidly. Therefore, it does not occur so frequently that the difference state between the current output pattern and the reference output pattern exceeds the set state. Therefore, imaging for updating the fixed pattern noise related information by the fixed pattern noise related information updating unit is not performed so frequently, and the fixed pattern noise information acquiring unit is operated each time the imaging output acquiring unit is operated. In comparison, the time required for reducing the fixed pattern noise can be shortened.
(12) Any one of the items (1) to (11), including an overall correction unit that corrects the amplification factor of the amplifier according to a temperature change of the CMOS image sensor with respect to all unit cells of the CMOS image sensor. Imaging device.
The amplification factor of the amplifier of the unit cell of the CMOS image sensor changes as the temperature of the CMOS image sensor changes. Therefore, it is desirable to adopt the features described in this section in order to obtain the same imaging output for imaging of the same imaging target under the same imaging conditions regardless of the temperature change of the CMOS image sensor. .
(13) The overall correction unit is
At least one common amplifier provided in common to a plurality of unit cells that are at least part of the plurality of unit cells of the CMOS image sensor;
The imaging apparatus according to item (12), including: a common amplifier control unit that changes an amplification factor of the at least one common amplifier with a temperature change of the CMOS image sensor.
The common amplifier may be provided in common for all the unit cells of the CMOS image sensor, or all the unit cells may be divided into a plurality of groups, and one common amplifier may be provided for each group. In any case, according to the common amplifier and the common amplifier control unit, the overall correction unit of the item (12) can be easily realized.
(14) a substrate holding device for holding a circuit board;
A component supply device for supplying electronic circuit components to be mounted on a circuit board held by the substrate holding device;
A mounting device for receiving electronic circuit components from the component supply device by a component holder and mounting the electronic circuit components on the circuit board held by the substrate holding device;
A component imaging device for imaging an electronic circuit component held by the component holder;
An image processing device for processing an imaging output representing an image of an electronic circuit component imaged by the component imaging device to obtain a holding position error of the electronic circuit component by the component holder;
A mounting control unit that controls the mounting apparatus so as to correct the holding position error acquired by the image processing apparatus and mount the circuit board on the circuit board held by the board holding apparatus. And
An electronic circuit component mounting machine, wherein the component imaging device includes the imaging device according to any one of (1) to (13).
(15) a substrate holding device for holding a circuit board;
A component supply device for supplying electronic circuit components to be mounted on a circuit board held by the substrate holding device;
A mounting device for receiving electronic circuit components from the component supply device by a component holder and mounting the electronic circuit components on the circuit board held by the substrate holding device;
A reference mark imaging device that images the reference mark;
An image processing device that processes an imaging output representing an image of a reference mark imaged by the reference mark imaging device, and acquires relative position information that is information regarding a relative position between the reference mark and the reference mark imaging device;
An electronic circuit component mounting machine including: a mounting control unit that controls the mounting device based on the relative position information acquired by the image processing device;
An electronic circuit component mounting machine, wherein the reference mark imaging device is constituted by the imaging device according to any one of (1) to (14).
In the electronic circuit component mounting machine, reference marks are provided on various objects, and the mounting device and the electronic circuit component mounting machine are controlled based on the relative position information between the reference mark and the reference mark imaging device. (A) Improvement of the mounting position accuracy of the electronic circuit component on the circuit board, (b) Reduction of receiving errors from the component supply device of the electronic circuit component by the mounting device, and (c) Reduction of the electronic circuit component by the mounting device. At least one of reduction of mounting errors on the circuit board and (d) prevention of malfunction of the electronic circuit component mounting machine can be achieved. For the above (a) and (c), for example, a reference mark is provided on the circuit board. For the above (b), for example, a component supply tool (feeder or tray) for supplying electronic circuit components is provided. Reference marks are provided, and their relative position errors are acquired as relative position information between the reference marks and the reference mark imaging device. For the above (d), for example, a reference mark is provided on a component of the electronic circuit component mounting machine, such as a component holder such as a suction nozzle that holds an electronic circuit component, or a holder holder that holds a component holder. If the relative position between the reference mark and the reference mark imaging device is different from the expected relative position, the electronic circuit component mounting machine is stopped to prevent malfunction.

It is a perspective view which shows the electronic circuit component mounting system provided with two or more mounting modules as an electronic circuit component mounting machine which is one Embodiment of claimable invention. It is a perspective view which shows a board | substrate conveyance apparatus etc. about a part of said mounting module. It is a perspective view which shows the mounting head and head movement apparatus of the mounting apparatus of the said mounting module. FIG. 4A is a perspective view showing the mounting head, FIG. 4A is a diagram showing a mounting head provided with one nozzle holder, and FIG. 4B is a diagram showing a mounting head provided with twelve nozzle holders. is there. It is a perspective view which removes a cover and shows the mounting head provided with 12 said nozzle holders. It is a block diagram which shows notionally the structure of the component imaging device of the said mounting module. It is a figure which shows notionally a part of CMOS image sensor of the said component imaging device. It is an equivalent circuit diagram of one unit cell of the unit cell existence area of the CMOS image sensor. It is a figure which shows the said unit cell presence area notionally. It is a chart which shows an example of a black area output pattern. It is a figure which shows notionally an example of the imaging target of the said component imaging device. It is a figure which shows notionally the situation where the fixed pattern noise of the imaging area of the said CMOS image sensor changes with the change of the temperature of a CMOS image sensor. It is a flowchart which shows a part of control program in another embodiment. It is a figure which shows the state of the fixed pattern noise reduction in another embodiment.

  Hereinafter, an embodiment of the claimable invention will be described with reference to the drawings. In addition to the following embodiment, the claimable invention can be implemented in various modifications based on the knowledge of those skilled in the art, including the aspects described in the above [Aspect of the Invention] section.

  FIG. 1 shows the appearance of the electronic circuit component mounting system. The present mounting system is configured by a plurality of mounting modules 10 being arranged and fixed in a row adjacent to each other on a common base 12. Each of the plurality of mounting modules 10 corresponds to an electronic circuit component mounting machine that is an embodiment of the claimable invention, and shares the mounting of the electronic circuit components on the circuit board and performs them in parallel.

The mounting module 10 is described in detail in, for example, Japanese Patent Application Laid-Open No. 2004-104075, and parts other than those related to the claimable invention will be briefly described.
As shown in FIG. 2, each mounting module 10 can be billed as follows: module main body 18, substrate transport device 20, substrate holding device 22, component supply device 24, mounting device 26, reference mark imaging device 28 (see FIG. 3). A component imaging device 30 and a control device 32 according to an embodiment of the invention are provided.

  As shown in FIG. 2, the board transfer device 20 includes two board conveyors 34 and 36, and is provided at the center in the front-rear direction of the mounting module 10 of the base 38 constituting the module body 18. The mounting module 10 is transported in a horizontal direction that is parallel to the direction in which the mounting modules 10 are arranged. The substrate holding device 22 is provided for each of the two substrate conveyors 34 and 36. Although not shown in the drawings, a support member for supporting the circuit board 40 from below and both side edges parallel to the conveying direction of the circuit board 40 are provided. Each of the clamp members includes a clamp member that holds the circuit board 40 in a posture in which a mounting surface on which the electronic circuit component is mounted is horizontal. The direction in which the circuit board 40 is conveyed by the board conveying device 20 is the X-axis direction, and the plane parallel to the mounting surface of the circuit board 40 held by the substrate holding device 22, and the direction perpendicular to the X-axis direction in the horizontal plane is Y Axial direction.

  The component supply device 24 is provided on one side in the Y-axis direction with respect to the substrate transfer device 20 of the base 38 and on the front side of the mounting module 10. The component supply device 24 supplies electronic circuit components by a tape feeder (hereinafter abbreviated as “feeder”) 46, which is a kind of component feeder, for example, and a plurality of feeders 46 and feeder support to which these feeders 46 are attached. Base (not shown). Each of the plurality of feeders 46 supplies a large number of electronic circuit components in a state of being held by a tape, and each of the plurality of feeders 46 holding different types of electronic circuit components has each component supply unit extending along the X-axis direction. Attached to the feeder support stand in line. The component supply device may be a device that supplies electronic circuit components by a tray.

  As shown in FIGS. 2 and 3, the mounting device 26 includes a mounting head 60 that is a working head and a head moving device 62 that moves the mounting head 60. As shown in FIG. 3, the head moving device 62 includes an X-axis direction moving device 64 and a Y-axis direction moving device 66. The Y-axis direction moving device 66 includes a linear motor 70 that is provided across the component supply unit of the component supply device 24 and the substrate holding device 22 on the beam 68 that constitutes the module main body 18, and serves as a Y axis as a movable member. The slide 72 is moved to an arbitrary position in the Y-axis direction. The X-axis direction moving device 64 is provided on the Y-axis slide 72 and is moved in the X-axis direction with respect to the Y-axis slide 72 and is relatively moved in the X-axis direction with respect to each other. 76 and an X-axis slide moving device 78 for moving these slides 74 and 76 in the X-axis direction (only a moving device for moving the first X-axis slide 74 is shown in FIG. 3). . Each of the two X-axis slide moving devices includes, for example, a servo motor which is a kind of an electric rotary motor serving as a drive source, and a feed screw mechanism including a ball screw and a nut. Move to any position in the axial direction.

  The mounting head 60 is detachably mounted on the second X-axis slide 76, and the head moving device 62 allows the mounting head 60 to be arbitrarily attached in a mounting work area that is a moving area straddling the component supply unit 24 and the substrate holding device 22. Moved to position. The mounting head 60 holds electronic circuit components by a suction nozzle 86 which is a kind of component holder. The mounting head 60 holds the suction nozzle 86 and the number of nozzle holders constituting the holder holding portion is different. A plurality of types of mounting heads 60 are prepared and selectively attached to the second X-axis slide 76 according to the type of circuit board 40 on which electronic circuit components are mounted.

  For example, the mounting head 60a shown in FIG. 4A has one nozzle holder 88a and holds one suction nozzle 86a, and the mounting head 60b shown in FIG. 4B has a plurality of, for example, three nozzle holders 88b. With the above (12 in the illustrated example), a maximum of 12 suction nozzles 86b can be held. The suction nozzle 86 includes a suction tube 90 and a background forming plate 92, and a plurality of types in which at least one of the diameter of the component suction surface of the suction tube 90 and the diameter of the background forming plate 92 having a circular shape in plan view is different. There are suction nozzles 86, which are used depending on the type of electronic circuit parts to be sucked. The suction nozzle 86a has a component suction surface and a diameter of the background forming plate 92a larger than those of the suction nozzle 86b, and is used for mounting a large electronic circuit component.

  Although not shown, the nozzle holder 88a in the mounting head 60a is a moving device provided in the head main body, provided in the head main body so as to be movable in the axial direction and in the vertical direction and rotatable about its own axis. It is moved up and down and rotated by the lifting device and the rotating device. As shown in FIG. 5, the mounting head 60 b includes a rotating body 100 provided on the head main body 96 so as to be rotatable around a vertical rotation axis, and a rotating body rotation that rotates the rotating body 100 in both forward and reverse directions at an arbitrary angle. The rotary head includes the device 102. In the rotator 100, the nozzle holder 88b is parallel to the rotation axis of the rotator 100 at twelve positions spaced at equal intervals on the circumference around the rotation axis, and equidistant from the mounting head 60b. The suction nozzle is provided so as to be relatively movable in any direction and to be rotatable around its own axis, and at the protruding end from the rotating body 100 (the lower end when the mounting head 60 is attached to the second X-axis slide 76). 86b is detachably held.

  The twelve nozzle holders 88b are swung around the rotation axis of the rotating body 100 by the rotation of the rotating body 100, and are sequentially moved to the component suction mounting position which is one of the twelve stop positions. It is lifted and lowered by a lifting device 104 which is a moving device provided at a position corresponding to 96 component suction mounting positions. The nozzle holder 88b is further rotated around its own axis by a holder rotating device 106 provided in the head body 96. As shown in FIG. 3, the reference mark imaging device 28 is mounted on the second X-axis slide 76 and moved together with the mounting head 60 by the head moving device 62.

  As shown in FIG. 2, the component imaging device 30 is provided in a portion of the base 38 between the substrate transfer device 20 and the component supply device 24, and illuminates the electronic circuit component sucked by the suction nozzle 86. Illuminate from below and image by the camera 118. As conceptually shown in FIG. 6, the component imaging apparatus 30 mainly includes a camera 118, and the camera 118 includes an imaging element 120 including a CMOS image sensor and an imaging element controller 122. The unit cell existence area 124 of the imaging device 120 includes an imaging area 126 and an optical black area 128 as shown in FIG. In the unit cell existence area 124, unit cells 130 represented by the equivalent circuit of FIG. 8 are arranged in a lattice form as shown in FIG. This point is the same in both the imaging area 126 and the optical black area 128. However, in the optical black area 128, light incident on the unit cells 130 for one or more setting columns (a plurality of columns in the present embodiment) is incident. Blocked by the mask, when the unit cell existence area 124 is exposed for a certain period of time and an effective imaging signal corresponding to the exposure time is output from the imaging area 126, the optical black area 128 is equivalent to the same exposure time. A light-shielded imaging signal is output. Note that the camera 118 in this embodiment does not include a mechanical shutter or an aperture, and the “exposure” is “charge” from when the previous imaging signal is output from each unit cell 130 until the next imaging signal is output. "Exposure time" means "charge accumulation time".

  An output signal from the unit cell existence area 124 is amplified by the common amplifier 132 and then supplied to the imaging data processing unit 140. The imaging data processing unit 140 includes each processing unit represented by the functional blocks in FIG. 6, and the amplified imaging signal is supplied to the imaging data acquisition unit 142, where digital data is converted from the imaging signal that is an analog signal. Is converted into imaging data. In this embodiment, the imaging data is 256 gradation gray value data.

  First, a light-shielded imaging signal from the optical black area 128 is supplied to the imaging data acquisition unit 142, and a black area output pattern (hereinafter abbreviated as an output pattern) is acquired. As an example of this output pattern, as shown in FIG. 10, light-shielded imaging data from the optical black area 128 is arranged in association with the position (coordinates) of the unit cell 130.

  Subsequently, an effective imaging signal is supplied from the imaging area 126 to the imaging data acquisition unit 142, and converted into effective imaging data that is gray level data of 256 gradations. The effective imaging data is supplied to the imaging data correction unit 144, and after being corrected, the effective imaging data is supplied to the image processing computer 152 as an image processing apparatus via the communication control unit 150, and image processing is performed. By this image processing, the holding position error of the electronic circuit component by the suction nozzle 86 is acquired, and the information is supplied to the mounting control computer 154 provided in the control device 32 of the mounting module 10 described above, and the holding position error is corrected. And mounted on the circuit board 40. For example, when the mounting head 60b shown in FIG. 4B is attached to the module 10, 12 electronic circuit components 156 are basically attached to the 12 suction nozzles 86 as shown in FIG. Since these twelve electronic circuit components 156 are collectively imaged by the component imaging device 30, the holding position error of each electronic circuit component 156 is corrected and mounted on the circuit board 40. is there.

  In the imaging data correction unit 144, various corrections are performed. For example, the brightness that increases the brightness by adding a constant value to all of the effective imaging data, or a lookup table is used to make corrections that make different changes to each of the effective imaging data. At the same time, correction for removing fixed pattern noise is performed. Hereinafter, the correction for removing the fixed pattern noise will be described.

  As shown in FIG. 8, each unit cell 130 present in the unit cell existence area 124 includes an amplifier 162 that amplifies a voltage corresponding to the charge accumulated in the photodiode 160 that accumulates the charge according to the amount of received light. However, in the current technology, it is inevitable that the amplification factor of the amplifier 162 varies. Therefore, for example, when a dark background is imaged by the camera 118, as conceptually shown in FIG. 12, a bright spot (white spot, white spot, etc.) is called at a specific position in the image. Fixed pattern noise appears. The white spot 164 increases as the temperature of the image sensor 120 increases. The white point 164 is likely to adversely affect the acquisition of the position error of the electronic circuit component 156 and is desirably removed, particularly when the image of the electronic circuit component 156 is acquired as a bright image.

  Since this fixed pattern noise is unique to each camera 118, the fixed pattern noise is detected before the camera 118 is attached to the mounting module 10. As described above, since the white spot 164 increases as the temperature of the image sensor 120 increases, it is necessary to detect fixed pattern noise for each of a plurality of temperatures, and the detection is performed using a thermostatic chamber. Done. In other words, the camera 118 is placed in a thermostat, the temperature of the thermostat is increased in increments of a constant temperature (for example, 5 ° C.), and the fixed pattern noise is detected while the temperature of the camera 118 is stable at each temperature. It is done. Of course, when detecting the fixed pattern noise of the white spot 164, the imaging is performed in a dark environment so that light does not enter the camera 118. The appearance of fixed pattern noise changes not only with the temperature of the image sensor 120 but also with changes in imaging conditions such as the amplification factor of the common amplifier 132 and the exposure time. It is desirable that the detection of the fixed pattern noise is performed under the same imaging conditions as when acquiring effective imaging data that requires the removal of the fixed pattern noise.

  Even when the fixed pattern noise is detected, the imaging signal from the unit cell existence area 124 is first output from the optical black area 128 and is converted into light-shielded imaging data by the imaging data acquisition unit 142 to control imaging data processing. The black area output pattern storage unit 172 (hereinafter abbreviated as an output pattern storage unit) of the unit 170 stores the output pattern in association with the temperature of the image sensor 120 at the time of acquisition.

  Following the output from the optical black area 128, the output from the imaging area 126 is performed, converted into effective imaging data by the imaging data acquisition unit 142, and supplied to the fixed pattern noise detection unit 174. In the fixed pattern noise detection unit 174, an average value of all effective imaging data is acquired, and a quotient δ obtained by dividing each effective imaging data by the average value is obtained. Then, each quotient δ is compared with a preset first threshold value, and if it is larger than the threshold value, it is associated with the coordinate value of the unit cell 130 that has output the effective imaging data corresponding to the quotient δ. And stored in the singularity information storage unit 176. In the present embodiment, when the quotient δ is larger than the threshold value, a deviation unit cell having a particularly large degree of deviation from the average level of the effective imaging data is set, and the position (coordinate) of the deviation unit cell and the deviation The quotient δ, which is a value representing the degree, is associated and stored in the singular point information storage unit 176 as fixed pattern noise related information in the form of a fixed pattern noise appearance table. In this embodiment, since fixed pattern noise is detected in increments of 5 ° C. from 0 ° C. to 60 ° C., 13 sets of temperatures and combinations of output patterns are stored in the output pattern storage unit 172 as 13 sets of temperatures. The combination with the fixed pattern noise related information is stored in the singularity information storage unit 176. The output pattern may be stored by associating all of the light-shielded imaging data with the position (coordinates) of the unit cell 130, and dividing the individual light-shielded imaging data by the average value of all the light-shielded imaging data. Only those exceeding the second threshold value may be stored in association with the position (coordinates) of the unit cell 130. In the present embodiment, the former is used.

The reference output pattern which is the output pattern of the optical black area 128 stored in the output pattern storage unit 172 and the fixed pattern noise related information stored in the singular point information storage unit 176 are stored in the mounting module 10 by the camera 118. After being attached, the current pattern noise, which is a fixed pattern noise of the current imaging data acquired by imaging of the imaging target, is corrected as follows.
When imaging of an imaging target is performed, output from the optical black area 128 is first performed, and a current output pattern represented by a set of light-shielded imaging data whose output is digitized by the imaging data acquisition unit 142 is a temperature estimation unit 180. Are compared with the 13 reference output patterns stored in the output pattern storage unit 172, and the temperature corresponding to the reference output pattern that is most approximated among these reference output patterns is estimated as the temperature of the image sensor 120. Is done. Then, fixed pattern noise related information corresponding to the estimated temperature is selected as noise correction information, and is read out from the singular point information storage unit 176 by the imaging data correction unit.

  Following the output from the optical black area 128, the output from the imaging area 126 is performed, digitized by the imaging data acquisition unit 142, the current imaging data is acquired, and supplied to the imaging data correction unit 144. In the imaging data correction unit 144, among these current imaging data, the current imaging data from the deviation unit cell represented by the fixed pattern noise related information read out from the singular point information storage unit 176 by the imaging data correction unit as described above, The fixed pattern noise is corrected by multiplying the reciprocal of the quotient δ. The corrected imaging data in which the fixed pattern noise is corrected is supplied to the image processing computer 154 via the communication control unit 150.

Furthermore, in this embodiment, the temperature information estimated by the temperature estimation unit 180 is supplied to the image sensor controller 122 by the control data supply unit 182 and the common amplifier 132 is controlled based on the temperature information. Thus, the change in the magnitude of the imaging signal accompanying the change in the temperature of the imaging element 120 can be reduced.
When the temperature of the imaging device 120 rises, the magnitude of the imaging signal for the same amount of light received by the unit cell 130 usually increases. In this embodiment, the increase in the magnitude of the imaging signal is caused by the common amplifier 132. It is suppressed by reducing the amplification factor. Therefore, regardless of the temperature change of the image sensor 120, a change in the magnitude of the image pickup signal with respect to the amount of received light is suppressed, and an image pickup signal with less influence of the temperature change is obtained.
In addition to the estimated temperature information, the control data supply unit 182 supplies various data necessary for controlling the image sensor 120 to the image sensor controller 122. Although not shown, the temperature estimation unit 180 also supplies the estimated temperature information to the imaging data correction unit 144, and the imaging data correction unit 144 based on the temperature information, the singular point information storage unit 176. From this, the fixed pattern noise related information corresponding to the temperature of the image sensor 120 is read out and used to correct the effective image data.

As is clear from the above description, the imaging data acquisition unit is configured by the control data supply unit 182, the imaging element controller 122, and the imaging data acquisition unit 142. Further, the singular point information storage unit 176 constitutes a departure pattern noise related data storage unit as an example of the fixed pattern noise related information storage unit, and the output pattern storage unit 172 and the temperature estimation unit 180 serve as a sensor temperature acquisition unit. The imaging data correction unit 144 constitutes a fixed pattern noise reduction unit, and the output pattern storage unit 172 constitutes a reference output pattern storage unit.
Further, the quotient δ, which is a value indicating the degree of deviation of the deviation unit cell, corresponds to the deviation data. Although the reciprocal of the quotient δ corresponds to the correction data, the correction data is not stored in the singular point information storage unit 176 in the present embodiment.

In the present embodiment, the fixed pattern noise is corrected after the imaging signal is digitized into imaging data. However, the fixed pattern noise is corrected in the state of the imaging signal before digitization. It is also possible to make it.
For example, the quotient δ representing the fixed pattern noise corresponding to the temperature estimated by the temperature estimation unit 180 or its reciprocal 1 / δ is supplied from the singular point information storage unit 176 to the image sensor controller 122 together with the coordinate value of the deviation unit cell. The fixed pattern included in the image pickup signal supplied from the image pickup device 120 to the image pickup data acquiring unit 142 is controlled by the image pickup device controller 122 based on the quotient δ or the reciprocal 1 / δ. Noise can be corrected.

As described above, the fixed pattern noise can be corrected in the state of the imaging signal, or can be corrected after being converted into imaging data. "Includes" imaging signal "and" imaging data ".
However, since the “imaging signal” is analog imaging data and the “imaging data” is digital imaging data, both can be considered as “imaging data” in a broad sense.

  In the embodiment, the fixed pattern noise related information is acquired using a thermostatic bath before the camera 118 is attached to the mounting module 10 and is stored in the singular point information storage unit 176, which is essential. Instead, it is also possible to obtain the fixed pattern noise related information after the camera 118 is attached to the mounting module 10. Hereinafter, the embodiment will be described with reference to FIG.

  Also in the present embodiment, the configurations of the electronic circuit component mounting system and the component imaging device 30 are the same as those in the above-described embodiment, and their control methods are different. The control device 32 of the mounting module 10 stores a control program for controlling the electronic circuit component mounting system and the component imaging device 30. Among the control programs, to reduce fixed pattern noise of the imaging output. FIG. 13 is a flow chart showing only the portion taken out.

The control program represented by this flowchart is repeatedly executed by the control device 26 while the electronic module is mounted on the mounting module 10.
First, in S1, initial processing such as clearing the output pattern storage unit 172 and singular point information storage unit 176 and resetting a counter is executed. Next, in S2, imaging in a non-light incident state is performed. For example, in a state where the mounting heads 60a and 60b are not positioned above the camera 118, imaging is performed with the illumination device 116 turned off. Since the camera 118 has a shallow depth of field, a substantially uniform imaging signal can be obtained if imaging is performed in a state where the camera 118 is not facing the mounting heads 60a and 60b. If the image is taken in a state in which the electronic circuit component 156 is held by the suction nozzle 86 having a dark, uniform and black background forming plate 92, the same image pickup signal as the background can be obtained.

  Of these image pickup signals, S3 is executed based on the signal from the optical black area 128, and a reference output pattern is acquired and stored in the output pattern storage unit 172. Further, S4 is executed based on the imaging signal from the imaging area 126, and the fixed pattern noise related information is acquired and stored in the singular point information storage unit 176.

  Subsequently, in S5, the illumination device 116 illuminates from below to pick up an image of the electronic circuit component 156 that is an image pickup target, and in S6, image pickup data is acquired. Acquisition of light-shielded imaging data (output pattern) from the optical black area 128 and acquisition of effective imaging data from the imaging area 126 are performed and temporarily stored in a RAM (not shown). In S7, the correction of the fixed pattern noise in the acquired imaging data is performed in the same manner as in the above embodiment based on the fixed pattern noise related information acquired in S4. Thereafter, in S8, it is determined whether or not imaging of the planned electronic circuit component 156 (installation of the planned electronic circuit component 156) has been completed. Since the determination result is normally NO, S10 and subsequent steps are executed.

Since the non-light-incidence imaging in S2 and the imaging target imaging in S5 are performed subsequently, the temperature of the image sensor 120 does not change during that time, and “at the time of non-light-incidence imaging (fixed pattern noise information acquisition unit) The temperature of the image sensor 120 (CMOS image sensor) is the same at the time of acquisition of fixed pattern noise information by the imaging device and at the time of imaging target imaging (when the imaging output acquisition unit acquires the imaging output). An embodiment of the invention described in the item (1) is such that when the conditions described in the item 1) are satisfied, S10 to S14 are omitted, and the determination result in S8 is NO, the execution of the program returns to S2. It will be.
In addition, the fact that non-light-incidence imaging and imaging target imaging are continuously performed is fixed within a time range that is set to be extremely short with respect to the acquisition time of the imaging output by the imaging output acquisition unit. This means that acquisition of fixed pattern noise information is performed by the pattern noise information acquisition unit. If S10 to S14 are omitted and the determination result in S8 is NO, the execution of the program returns to S2. Can be considered as an embodiment of the invention described in item (9).

  However, in the embodiment shown in FIG. 13, if the determination result in S8 is NO, the count value n of the counter is incremented in S10, and whether or not the count value n is greater than or equal to the set count value N in S11. However, since the determination result is NO at first, the program execution returns to S5. S5 to S11 are repeatedly executed, and eventually the determination result of S11 becomes YES, the count value is reset to 0 in S12, and the absolute value | ΣΔ | of the difference integral is acquired in S13. The absolute value | ΣΔ | of the integral of the difference between the reference output pattern previously acquired and stored in the output pattern storage unit 172 and the current output pattern acquired in S6 and temporarily stored in the RAM is acquired. It is done. If the absolute value | ΣΔ | of the integral of this difference is larger than the set value S, it means that a relatively large difference has occurred between the reference output pattern and the current output pattern. Returning to FIG. 2, the reference output pattern and the fixed pattern noise related information are updated.

  The absolute value | ΣΔ | of the integration of the difference is set to be slightly smaller than the value corresponding to the practically allowable limit of the temperature change of the image sensor 120, and the set count value N is determined as YES in S14. The determination result of S11 is set to a value that will be YES at least once, preferably a plurality of times until it becomes. According to the present embodiment, it is ensured that the temperature change of the image sensor 120 does not exceed a practically allowable limit, and the steps S10 to S14 are omitted, and each time the electronic circuit component 156 is imaged, a reference is made. Compared to the embodiment in which the acquisition of the output pattern and the fixed pattern noise related information is performed, the number of acquisitions of the reference output pattern and the fixed pattern noise related information is reduced, and the mounting work efficiency of the electronic circuit component 156 is improved. An effect is obtained.

  Note that, as the set count value N is set to a smaller value, it is surely ensured that the temperature change of the image sensor 120 does not exceed a practically allowable limit, but the reference output pattern and the fixed pattern noise The related information is frequently updated, and the mounting work efficiency of the electronic circuit component 156 decreases. On the other hand, if the set count value N is too large, the degree of guarantee that the temperature change of the image sensor 120 does not exceed the practically allowable limit is low. The same can be said for the absolute value | ΣΔ | of the integral of the difference. Therefore, the set count value N and the absolute value | ΣΔ | of the integral of the difference should be appropriately set in consideration of the above circumstances.

  As is clear from the above description, in the present embodiment, the fixed pattern noise information acquisition unit is configured by the part of the control device 32 that executes S2 and S4, the imaging element controller 122, and the imaging data acquisition unit 142. The singular point information storage unit 176 constitutes a fixed pattern noise related information storage unit. In addition, an imaging output acquisition unit is configured by the part that executes S5 and S6 of the control device 32, the imaging device controller 122 and the imaging data acquisition unit 142, and the part that executes S7 of the control device 32, and the imaging data correction unit 144 constitutes a fixed pattern noise reduction unit, an output pattern storage unit 172 constitutes a reference output pattern storage unit, and a part for executing S13, S14, S2 and S3 of the control device 32 provides a reference output pattern update unit. The fixed pattern noise related information updating unit is configured by the part that executes S2 and S4 after the determination result of S14 of the control device 32 is YES.

In the above embodiment, the execution of steps S10 to S12 can be considered as a determination as to whether or not the set time has elapsed. S13 and S14 are omitted, and after the execution of S12, the execution of the program is performed in step S2. If it returns to (2), the aspect will become embodiment of the invention as described in said (9) term exactly.
In that case, the fixed pattern noise information acquisition unit is configured by the part that executes S2 and S4 of the control device 32, the imaging element controller 122, and the imaging data acquisition unit 142, and the part that executes S5 and S6 of the control device 32 The imaging element controller 122 and the imaging data acquisition unit 142 constitute an imaging output acquisition unit, and the part that executes S7 of the control device 32 and the imaging data correction unit 144 constitute a fixed pattern noise reduction unit. .

  In the embodiment shown in FIG. 13, the correction of the fixed pattern noise in S7 is performed in the same manner as in the above embodiment, but the acquisition and storage of the fixed pattern data in S4 is acquired by non-light incident state imaging. All of the received non-incident imaging data is stored in the fixed pattern data storage unit, and the correction of the fixed pattern noise in S7 is to subtract each of the corresponding non-incident imaging data from each of the imaging data. It is also possible to do. An example of how fixed pattern noise is reduced by this method is shown in FIG. FIG. 14 (a) shows an image corresponding to non-incident imaging data, FIG. 14 (b) shows an image corresponding to imaging data, and FIG. 14 (c) shows corrected imaging data in which fixed pattern noise is corrected. The corresponding image is shown. In the image of FIG. 14 (c), it can be seen that the white spots existing in the image of FIG. 14 (b) are almost eliminated.

  Although the above has described the case where the fixed pattern noise is a so-called white spot, the claimable invention can be applied to the case where the fixed pattern noise is a so-called black spot. When a dark image to be imaged is acquired on a bright background, that is, when a silhouette image is acquired, a dark spot, which is darker than other parts, may appear as fixed noise in the bright background. This removal of sunspot noise is, for example, background image data acquired by imaging only a bright background under the same imaging conditions as when imaging an imaging target, or a state in which bright uniform light is incident on the entire image sensor. If the imaging data representing the silhouette image of the imaging target is subtracted from the noise removal data that is one of the incident light imaging data acquired by imaging under the same imaging conditions as when imaging the imaging target at While the noise is reduced, imaging data representing a state in which a bright imaging target image exists in a dark background, that is, an image obtained by inverting the brightness of an actually acquired image is obtained. This imaging data itself can also be used for evaluating the position, size, etc. of the imaging target. However, if this imaging data is subtracted from imaging data that uniformly represents a bright image, it is possible to obtain noise-removed imaging data in a state where black spot noise has been removed from the actually acquired image.

  Also, as in the previous embodiment, each noise removal data is divided by the average value of the noise removal data, and the deviation unit cell is defined as a deviation unit cell in which the quotient is significantly different from other quotients. It is also possible to reduce the fixed pattern noise of the black spots by correcting the pattern noise. In that case, the correction of the fixed pattern noise may be performed by subtraction such as subtracting the imaging data from the noise removal data as in the above embodiment, or by multiplication by multiplying the imaging data from the deviation unit cell by the reciprocal of the quotient. Is possible.

  In the above embodiment, the imaging data correction unit 144, the output pattern storage unit 172, the fixed pattern noise detection unit 174, the singular point information storage unit 176, the temperature estimation unit 180, and the like are provided in the camera 118. At least a part of these may be provided in a computer outside the camera. If these are provided outside the camera, a general-purpose camera can be used.

  Further, in the above embodiment, all the imaging data of the deviation unit cell is corrected by correcting the imaging data itself. However, if the degree of deviation is too large, the imaging of the unit cell is performed. The deviation may be corrected by interpolation using image data of a plurality of surrounding unit cells without using data. This is because a unit cell having an excessively high degree of deviation is likely to be damaged, and its imaging data is often not proportional to the amount of received light.

  Furthermore, in the above embodiment, the temperature of the image sensor 120 is acquired based on the output pattern of the optical black area 128. However, a temperature sensor is provided inside the camera 118, particularly in a portion close to the image sensor 120. It may be provided and the temperature may be detected.

10: Mounting module 28: Reference mark imaging device 30: Component imaging device 32: Control device 60a, b: Mounting head 86: Suction nozzle 88: Nozzle holder 90: Suction tube 92: Background forming plate 116: Illumination device 118: Camera 120 : Imaging device (CMOS image sensor) 122: Imaging device controller 124: Unit cell existence area 126: Imaging area 128: Optical black area 130: Unit cell 132: Common amplifier 140: Imaging data processing unit 142: Imaging data acquisition unit 144: Imaging Data Correction Unit 150: Communication Control Unit 152: Image Processing Computer 156: Electronic Circuit Component 160: Photodiode 162: Amplifier 164: White Spot 170: Imaging Data Processing Control Unit 17 2: Black area output pattern storage unit (output pattern storage unit) 174: Fixed pattern noise detection unit 176: Singular point information storage unit 180: Temperature estimation unit 182: Control data supply unit

Claims (8)

A CMOS image sensor in which a unit cell existence area, which is an area where a plurality of unit cells each having an amplifier and performing photoelectric conversion, includes an imaging area and an optical black area ;
An imaging output acquisition unit that acquires an imaging output by causing the CMOS image sensor to perform imaging of an imaging target;
Due to variations in amplification factors of the amplifiers of the plurality of unit cells in the imaging area of the CMOS image sensor, the CMOS image sensor is caused to perform imaging in a state where light incident on the CMOS image sensor is uniform. Fixed pattern noise information acquisition unit for acquiring information of fixed pattern noise generated by
A fixed pattern noise related information storage unit that stores fixed pattern noise related information that is either the fixed pattern noise information acquired by the fixed pattern noise information acquisition unit or information for correcting the fixed pattern noise. When,
Based on the fixed pattern noise related information stored in the fixed pattern noise related information storage unit, a fixed pattern noise reducing unit that reduces fixed pattern noise in the imaging output acquired by the imaging output acquisition unit ;
A reference output pattern storage unit for storing a pattern of the output from the optical black area when the acquisition of the image pickup output is performed by the pre-Symbol imaging output acquisition unit as the reference output patterns,
After storing the reference output pattern in the reference output pattern storage unit, when the imaging output acquisition unit acquires the imaging output, the current output pattern that is an output pattern obtained from the optical black area and the reference output A reference output pattern update unit that updates the reference output pattern by replacing the current output pattern with the reference output pattern when the difference state from the pattern is equal to or greater than the set state;
When the reference output pattern is updated by the reference output pattern update unit, the fixed pattern noise information acquisition unit is operated to acquire new fixed pattern noise information, and the fixed pattern noise related information storage unit An imaging device comprising: a fixed pattern noise related information update unit that updates fixed pattern noise related information. And a sensor temperature acquisition unit for acquiring a temperature of the CMOS image sensor when the imaging target is imaged by the CMOS image sensor, and
The fixed pattern noise related information storage unit stores a plurality of types of fixed pattern noise related information at each of a plurality of temperatures of the CMOS image sensor in association with each of the temperatures, and the fixed pattern noise reduction unit The imaging output acquisition based on the temperature acquired by the sensor temperature acquisition unit and the plurality of types of fixed pattern noise related information at each of the plurality of temperatures stored in the fixed pattern noise related information storage unit The imaging apparatus according to claim 1, wherein the fixed pattern noise in the imaging output acquired by the unit is reduced by correction.   A reference output pattern storage unit stores an output pattern of the optical black area corresponding to the plurality of temperatures of the CMOS image sensor as a plurality of types of reference output patterns in association with each of the plurality of temperatures, The sensor temperature acquisition unit is a current output pattern that is an output pattern of the optical black area at the time of acquisition of the imaging output by the imaging output acquisition unit, and a plurality of types of reference outputs stored in the reference output pattern storage unit The imaging apparatus according to claim 2, further comprising: a sensor temperature estimation unit that estimates a temperature of the CMOS image sensor at the time of imaging of the imaging target based on similarity to each pattern.   When the absolute value of the integral of the difference between the reference output pattern and the current output pattern is greater than or equal to a preset first set value, the reference output pattern update unit is in a difference state between the current output pattern and the reference output pattern The imaging apparatus according to any one of claims 1 to 3, wherein the reference output pattern is updated on the assumption that the value exceeds the set state.   5. The fixed pattern noise includes at least one of a bright white point compared to other parts in a dark background and a dark black point compared to other parts in a light background. An imaging apparatus according to claim 1.   The fixed pattern noise reduction unit is configured to obtain an average value of noise removal data that is an imaging output from the plurality of unit cells in the imaging area in a state where the light incident state on the entire CMOS image sensor is uniform. Data for noise removal is divided and a quotient different from other quotients by a second set value or more is defined as a deviation unit cell, and the fixed pattern is determined based on the noise removal data itself of the deviation unit cell. The imaging apparatus according to claim 1, wherein noise correction is performed.   When the quotient is larger than a third set value that is larger than the second quotient and the other quotient, the fixed pattern noise reduction unit is not based on the noise removal data itself of the deviation unit cell, and The imaging apparatus according to claim 6, wherein the fixed pattern noise is corrected by interpolation using imaging data of a plurality of peripheral unit cells. A substrate holding device for holding a circuit board;
A component supply device for supplying electronic circuit components to be mounted on a circuit board held by the substrate holding device;
A mounting device for receiving electronic circuit components from the component supply device by a component holder and mounting the electronic circuit components on the circuit board held by the substrate holding device;
A component imaging device for imaging an electronic circuit component held by the component holder;
An image processing device for processing an imaging output representing an image of an electronic circuit component imaged by the component imaging device to obtain a holding position error of the electronic circuit component by the component holder;
A mounting control unit that controls the mounting apparatus so as to correct the holding position error acquired by the image processing apparatus and mount the circuit board on the circuit board held by the board holding apparatus. And
An electronic circuit component mounting machine, wherein the component imaging device comprises the imaging device according to any one of claims 1 to 7.