JP2018017631A - Illumination control power supply and inspection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination control power supply which allows a strobe emission state to be set with two independent parameters and in which a control delay hardly occurs even when parameter settings are changed.SOLUTION: The illumination control power supply comprises: an acceptance unit 21 for accepting the set values of a strobe light emission width and a lighting ratio in the strobe light emission width; a strobe light emission width controller 24 for outputting an ON/OFF signal in which the set value of the strobe light emission width is set as a successive ON period, and controlling the length of a period in which an LED illuminator can emit a strobe light; a lighting ratio controller 25 for outputting an ON/OFF signal so that the ratio of an ON period to an OFF period within the period in which the LED illuminator 1 can emit a strobe light is set to be a set value of the lighting ratio, and controlling the lighting ratio; and a multiplier 28 to which the ON/OFF signal is inputted from each of the strobe light emission width controller 24 and the lighting ratio controller 25, for outputting a final output signal multiplied by each ON/OFF signal to the LED illuminator 1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an illumination control power source for controlling a strobe emission state of an LED illuminator, and an inspection system using the illumination control power source.

  For example, when an appearance inspection of a product is performed, an LED illuminator may be stroboscopically fired to image the product. At this time, the strobe light emission state is controlled by an illumination control power source connected to the LED illumination in accordance with the characteristics of the product and the LED illuminator (see Patent Document 1).

  By the way, there are a plurality of inspection lines in which LED illuminators are provided separately, and a plurality of types of products may be run through each inspection line. In such a case, it is necessary to realize strobe light emission according to two types of parameters, that is, the difference between each LED illuminator and the difference between product types in order to make the inspection accuracy in each inspection line uniform. is there.

  In order to satisfy such requirements, some lighting control power supplies are configured such that the strobe emission width and the target voltage value of the voltage applied to the LED illuminator by constant voltage control can be set independently. If this is the case, for example, the strobe emission width is varied so that the difference between the LED illuminators is absorbed, and the target voltage value in constant voltage control is changed according to the type of product. Can do. Therefore, the target voltage value applied to each LED illuminator can be made uniform for a certain product regardless of the LED illuminator, and the strobe light emission state can be easily set.

JP 2009-162728

  However, since the time during which the LED illuminator emits light is very short in strobe light emission, if the target voltage value for constant voltage control is changed according to the product, a large control delay occurs depending on the target voltage value. It may happen that a sufficient amount of light is not irradiated to the product during the shutter opening time.

  The present invention has been made in view of the above-described problems, and is an illumination control power source that can set the strobe emission state with two independent parameters and hardly causes a control delay even if the parameter settings are changed. And it aims at providing the inspection system using the same.

  That is, the illumination control power supply according to the present invention is an illumination control power supply that supplies power to an LED illuminator configured to be capable of strobe light emission, and includes a strobe light emission width and a lighting ratio of the LED illuminator within the strobe light emission width. And a strobe light emission for controlling the length of the period during which the LED illuminator can emit the strobe light, and an ON / OFF signal in which the strobe light emission width setting value is set as a continuous ON period. An ON / OFF signal that is set so that the ratio of the ON period and the OFF period becomes the set value of the lighting ratio within the period during which the LED illuminator can emit strobe light is output to control the lighting ratio. An ON / OFF signal is input from each of the lighting ratio controller, the strobe light emission width controller, and the lighting ratio controller. The final output signal calculated, characterized in that and a multiplier for outputting to the LED illuminator.

  Here, the strobe light emission means that the LED illuminator emits light one or more times within a time shorter than a predetermined time.

  If this is the case, the state of strobe light emission of the LED illuminator can be controlled independently by the two parameters of the strobe light emission width and the lighting ratio, so that the degree of freedom of control is kept equal to the conventional one, The voltage applied to the LED illuminator during strobe light emission can be made constant. Therefore, the occurrence of control delay can be reduced while the degree of freedom in setting the flash emission is high.

  During the ON period of the ON / OFF signal output from the strobe light emission width controller, a part of the ON period of the ON / OFF signal output from the lighting ratio controller is not removed, and the whole is surely made. In order for the lighting ratio to be realized so as to be included, the lighting ratio controller calculates a control period that is 1 / integer of the set value of the strobe emission width, and The length of the ON period or OFF period can be set for each control period calculated by the control period calculation unit, and the ratio of the sum of the ON period and the sum of the OFF period within the period in which the LED illuminator can emit strobe light is What is necessary is just to provide the lighting ratio signal output part which outputs the ON / OFF signal set so that it may become the setting value of the said lighting ratio.

  In order to allow the LED illuminator to repeatedly turn on and off within the strobe light emission width so as to realize temporally uniform strobe light emission, the lighting ratio signal output unit includes an ON period and a plurality of control periods. What is necessary is just to be comprised so that the ratio of the OFF period may output the ON / OFF signal set to the same value.

  In order to easily control the amount of light within the strobe light emission width in a manner substantially similar to that of PWM control, the lighting ratio signal output unit has the same ratio between the ON period and the OFF period in a plurality of control cycles. What is necessary is just to be comprised so that the set ON / OFF signal may be output.

  The strobe emission width is set to be short, and it is possible to substantially realize a gradation that cannot be realized even if output is repeated in the same manner with a pulse width that can be output in each control cycle, and can be realized with respect to the lighting ratio. In order to increase the number of gradations, when the strobe emission width is equal to or less than a predetermined value, the control cycle calculation unit calculates the time length so that a plurality of control cycles are included in the strobe emission width. In addition, the lighting ratio signal output unit may be configured to make the ratio of the ON period and the OFF period different from the other control periods for at least some of the control periods.

  In order to ensure that the LED illuminator is lit within the strobe light emission width so that each pulse constituting the ON / OFF signal output from the lighting ratio controller does not substantially cause a control delay, The control cycle calculation unit may be configured to calculate a control cycle having a cycle longer than the minimum pulse width that can be output from the lighting ratio signal output unit.

  In order to allow sufficient control of the amount of light according to the lighting ratio even when the strobe emission width is short, the control period calculation unit has a time length substantially ½ of the strobe emission width. As long as it is configured to calculate as the control period.

  In order to ensure that the ON period of the ON / OFF signal output from the lighting ratio signal output unit is included in the strobe light emission width without loss and to secure a necessary light amount, the strobe light emission width control is performed. The output start timing of the ON period in the ON / OFF signal output from the device is synchronized with the output start timing of the ON period of the ON / OFF signal output from the lighting ratio signal output unit. That's fine.

  In order to realize inspection in a desired illumination mode so that reflected light from the inspection object is sufficiently captured by the camera, the illumination control power source according to the present invention and the inspection object are irradiated with light. The LED illuminator, a camera disposed at a position where the inspection object can be imaged, and a shutter control unit that controls opening and closing of the shutter of the camera, and the shutter control unit includes the strobe An inspection system configured to open the shutter before the output start timing of the ON period of the ON / OFF signal output from the light emission width controller and close the shutter after the output end timing of the ON period. If it is.

  As described above, the illumination control power source according to the present invention can control the amount of light at the time of strobe light emission with parameters having two independent degrees of freedom, and at the same time, constant voltage control with the same target voltage value at the time of voltage application. Since the pulse can be controlled by this, it is possible to prevent the occurrence of a control delay in the strobe light emission control.

The schematic diagram which shows the illumination control power supply and inspection system which concern on one Embodiment of this invention. The functional block diagram which shows the structure of the illumination control power supply in the embodiment. The typical timing chart which shows the output in each illumination control power supply at the time of the test | inspection of the product A in the embodiment. The typical timing chart which shows the output in each illumination control power supply at the time of the test | inspection of the product B in the embodiment. The typical timing chart which shows the output in the illumination control power supply which concerns on another embodiment of this invention.

  The illumination control power source 2 and the inspection system 100 according to the first embodiment of the present invention will be described with reference to FIGS.

  The inspection system 100 according to the first embodiment includes a plurality of inspection lines, and a plurality of types of inspection objects having different reflection, transmission, and absorption characteristics with respect to light are passed through one inspection line.

  The inspection system 100 will be described in detail. As shown in FIG. 1, the LED illuminator 1 that is ring-shaped illumination, the illumination control power source 2 that controls the light emission mode of the LED illuminator 1, and the LED illuminator 1. A camera 3 that captures an image of the inspection object irradiated with light, and a shutter control unit 4 that controls the shutter of the camera 3 in conjunction with the illumination control power supply 2. The inspection system 100 causes the LED illuminator 1 to emit a stroboscopic light when an inspection object is carried directly under the LED illuminator 1. The reflected light of the strobe light from the inspection object enters the camera 3 through the central opening of the LED illuminator 1. The shutter control unit 4 is a control board having a CPU, memory, input / output means, A / C / D / C converter, etc., and controls the shutter opening time and timing of the camera 3. To do. In the present embodiment, the shutter control unit 4 is configured to be interlocked with the operation of the illumination control power source 2.

  The LED illuminator 1 is configured in a substantially ring shape, and has an inner peripheral surface that is inclined toward the central axis direction. A large number of LEDs are uniformly arranged on the inner peripheral surface, and the optical axes of the LEDs are gathered on the inspection object.

  The illumination control power supply 2 supplies electric power for causing the LED illuminator 1 to emit stroboscopic light at the timing when the inspection object is disposed immediately below the LED illuminator 1, and sets the state of the stroboscopic light emission by the user. Control is performed so that the strobe emission width and the lighting ratio are set. That is, the illumination control power source 2 is configured to use a strobe light according to two parameters: a strobe light emission period during which the LED illuminator 1 can emit light, and a lighting ratio when the light is turned on and off a plurality of times within the strobe light emission width. The state of light emission can be controlled with two degrees of freedom. The illumination control power source 2 is configured such that the current flowing through the LED illuminator 1 is constant in each pulse by constant voltage control, and the target voltage value during this constant voltage control is fixed in advance.

  The illumination control power source 2 includes a control board having a CPU, a memory, an A / D / D / A converter, and the like as hardware. The illumination control power source 2 executes at least the reception unit 21 and the strobe light emission width control by executing the illumination control program stored in the memory and cooperating with various devices as shown in the functional block diagram of FIG. The function as the device 24, the lighting ratio controller 25, and the multiplier 28 is exhibited. Details of the configuration and operation of each unit will be described below.

  The accepting unit 21 accepts a strobe light emission width, which is a parameter for setting a light emission state of strobe light emission, and a setting value of a lighting ratio from a user via an input / output unit such as a setting dial.

  In the present embodiment, the receiving unit 21 includes a strobe light emission width receiving unit 22 that receives a setting value related to a strobe light emission width, and a lighting rate receiving unit 23 that receives a setting value related to a lighting rate. Here, the strobe light emission width is a parameter for setting a period during which light emission of the LED illuminator 1 is permitted. In this embodiment, the strobe light emission width can be set to a period of 1 μs or more and 1000 μs or less, and one or a plurality of times of light emission within this time can be defined as strobe light emission. The lighting ratio is the ratio of the total time that the LED illuminator 1 is lit to the time length of the stroboscopic light emission width when the LED illuminator 1 is turned on and off within the strobe light emission width. Is a parameter for setting.

  The strobe light emission width controller 24 and the lighting ratio controller 25 output different ON / OFF signals based on the setting values of the strobe light emission width and the lighting ratio received by the receiving unit 21, respectively. is there. Each ON / OFF signal output from the strobe light emission width controller 24 and the lighting ratio controller 25 is multiplied by the multiplier 28 and output to the LED illuminator 1 as a final output signal.

  More specifically, the strobe light emission width controller 24 outputs an ON / OFF signal in which the set value of the strobe light emission width is set as a continuous ON period, and the length of the period during which the LED illuminator 1 can emit strobe light. Is to control. As shown in the timing charts of FIGS. 3 and 4, the ON period of the ON / OFF signal output from the strobe light emission width controller 24 is within the period during which the shutter of the camera 3 is opened by the shutter control unit 4. To fit. That is, the ON period start timing of the ON / OFF signal output from the strobe light emission width controller 24 is set after the shutter opening timing, and the ON period end timing is before the shutter closing timing. It is set. Therefore, the LED illuminator 1 can emit light at an arbitrary timing while the shutter of the camera 3 is opened.

  The lighting ratio controller 25 is set to ON / OFF set so that the ratio of the ON period and the OFF period becomes the set value of the lighting ratio received by the receiving unit 21 within the period in which the LED illuminator 1 can emit strobe light. An OFF signal is output to control the lighting ratio. As shown in FIGS. 3 and 4, in the present embodiment, the lighting ratio controller 25 is configured to output a periodic ON / OFF signal. The control cycle of the ON / OFF signal is appropriately set according to the time length of the strobe emission width received by the receiving unit 21.

  More specifically, the lighting rate controller 25 includes a control cycle calculation unit 26 that calculates an integral number of a set value of the strobe emission width received by the reception unit 21 as a control cycle, and the control cycle calculation. The length of the ON period or the OFF period can be set for each control cycle calculated by the unit 26, and the ratio of the sum of the ON period and the sum of the OFF period in the period in which the LED illuminator 1 can emit the strobe light is A lighting ratio signal output unit 27 that outputs an ON / OFF signal set to be a setting value of the lighting ratio. That is, as shown in FIG. 3, the setting of the strobe emission width received by the receiving unit 21 is N times (N natural number) of the time length of the cycle of the ON / OFF signal output by the lighting ratio signal output unit 27. It matches the time length of the value. In this embodiment, the start timing of the ON period of the ON / OFF signal output from the strobe light emission width controller 24, and the start timing of the ON period of the ON / OFF signal output from the lighting ratio signal output unit 27 are as follows. The lighting ratio signal output unit 27 is configured so as to be simultaneously. In this embodiment, the ratio between the ON period and the OFF period in each cycle reflects the set value of the lighting ratio received by the receiving unit 21, and the same pulse is output in each cycle. Further, the length of the ON period is set to be longer than the pulse width of the minimum resolution that can be output from the lighting ratio signal output unit 27, and the number of pulses output within the strobe light emission width is maximized. The control cycle calculation unit 26 calculates a control cycle. For example, the control cycle calculation unit 26 has a reference table (not shown) stored in advance for a control cycle that satisfies the above-described conditions for each combination of the strobe light emission width and the lighting ratio, and is received by the receiving unit 21. The control cycle corresponding to each set value is obtained from the reference table.

  Further, in the present embodiment, the ON / OFF signal output from the lighting ratio signal output unit 27 is configured to be included in the strobe light emission width for at least two cycles, and the LED illuminator 1 has the strobe light emission width. The lighting periods are uniformly distributed.

  As shown in FIG. 2, the multiplier 28 receives ON / OFF signals from the strobe light emission width controller 24 and the lighting ratio controller 25, and multiplies each ON / OFF signal to the final output signal. This is output to the LED illuminator 1. That is, as shown in the graphs of FIGS. 3 and 4, the multiplier 28 repeatedly outputs an ON / OFF signal only during a period in which the user wants to emit strobe light. In the present embodiment, the multiplier 28 is configured to control the output pulse at a constant voltage, and the voltage value is fixed to a predetermined value at the time of factory shipment, for example.

  An example of operations in the illumination control power supply 2 and the inspection system 100 configured as described above will be described with reference to the timing chart of FIG.

  FIG. 3A shows a control mode of strobe light emission when the product A flows as an inspection object directly below the LED illuminator 1 on the first inspection line, and FIG. The control mode of strobe light emission in the case where the product A flows as an inspection target directly below the LED illuminator 1 on the second inspection line is shown. FIG. 4 (a) shows a control mode of strobe light emission when the product B flows as an inspection target directly below the LED illuminator 1 on the first inspection line, and FIG. The control mode of strobe light emission when the product B flows as an inspection object directly below the LED illuminator 1 on the second inspection line is shown.

  As shown in FIGS. 3 and 4, the inspection system 100 is configured to perform strobe light emission with the same lighting ratio regardless of the difference in the LED illuminator 1 when the types of products to be inspected are the same. It is. On the other hand, even if the product to be inspected is the same, the inspection line is different, and if the LED illuminator 1 is different, the strobe emission width is varied to absorb the machine difference, and the LED illuminator 1 is different. The same amount of light is irradiated to the inspection object for each product.

  As shown in FIG. 3 and FIG. 4, for example, 2 Nμs and 2.25 Nμs are set as setting values of the strobe light emission width by the user in the illumination control power supply 2 provided in each inspection line. For example, when the same constant voltage control is performed, the LED illuminator 1 of the first inspection line takes into account the tendency that the amount of light is output larger than the second LED illuminator 1 of the inspection line, so that the same amount of light is obtained. It is set.

  Next, the user inputs a lighting ratio common to each type of product to each lighting control power source 2 regardless of each lighting control power source 2. That is, the setting value of the lighting ratio is set so that the lighting ratio is 50% in the case of the product A and 75% in the case of the product B.

  By setting in this way, when the product A flows as shown in FIG. 3, the illumination control power supply 2 of each inspection line has a strobe emission width different, and the lighting ratio is common at 50%. The strobe light emission can be executed by each LED illuminator 1.

  On the other hand, as shown in FIG. 4, when the product B flows, the illumination control power supply 2 of each inspection line changes the strobe emission width, and the lighting ratio is 75%, and the common strobe emission is used for each LED illumination. The device 1 can be executed.

  As described above, the inspection system 100 according to the present embodiment allows the illumination control power supply 2 to freely set two parameters of the strobe emission width and the lighting ratio, so that the inspection can be performed while absorbing the machine difference of the LED illuminator 1. It is possible to achieve strobe emission in the same state for each type of target product, and to obtain image data for each inspection target.

  In addition, since the illumination control power supply 2 supplies power to the LED illuminator 1 by constant voltage control in which the target voltage value of each pulse is fixed, control by changing the target voltage value as in the prior art. There is no delay problem. That is, it is possible to repeat pulse light emission with a clear shape within a strobe light emission width a plurality of times, and to realize ideal strobe light emission.

  The effect that the target voltage value described above can be fixed and control delay can be prevented is that the illumination control power supply 2 of the present embodiment can realize two-degree-of-freedom control with two parameters of the strobe emission width and the lighting ratio. Therefore, the target voltage value need not be changed in order to realize the same degree of control freedom as in the prior art.

  Other embodiments will be described.

  Depending on the lighting ratio set by the lighting ratio signal output unit, the length of the ON period may be changed according to the control cycle. That is, even if the lighting ratio cannot be achieved if the same ON period and OFF period are set in each control cycle, for example, the pulse at a ratio of the ON period and the OFF period that is different from the other control periods in the final control period within the strobe emission width. Can further increase the number of gradations that can be realized. Further, the number of control periods or the number of pulses included in the strobe light emission width may be two or more, or may be only one. Specifically, as shown in the timing chart of FIG. 5, three control periods or pulses may be included in the strobe light emission width, and the width of the final pulse may be different from the width of other pulses. In the example of FIG. 5, 42% is set as the lighting rate. In such a case, the lighting rate controller outputs the final pulse so that the final pulse is set to almost half of the other pulses. ON / OFF signal to be controlled is controlled.

  If this is the case, it is possible to achieve strobe light emission that achieves a finer number of gradations than in the embodiment.

  Next, other embodiments of the present invention will be described.

  In the above-described embodiment, the illumination control power source is used for an inspection system including a plurality of inspection lines. However, the illumination control power source may be used for an inspection system having only one inspection line. Further, the illumination control power source may be used for causing the LED illuminator to emit strobe light in a desired manner even for uses other than inspection.

  The ON periods of the ON / OFF signals output from the strobe light emission width controller and the lighting rate controller do not necessarily have the same start timing, and may be synchronized with a predetermined phase difference. . In short, it is only necessary that the length of the strobe emission width is an integral multiple of the control cycle of the ON / OFF signal output from the lighting ratio controller. If it is such, it becomes possible to make the ratio of the sum total of the time when the LED illuminator is lit within the strobe light emission width coincide with the lighting ratio input to the reception unit.

  In addition, it absorbs machine differences of LED illuminators at the lighting rate, and the difference in the characteristics of the inspection target can be dealt with by changing the stroboscopic light emission width. The same stroboscopic light emission state for each product with multiple LED illuminators with different machine differences May be realized.

  Further, in addition to the strobe light emission width and the lighting ratio, the applied voltage may be adjustable and may be controlled by these three parameters. In addition, various modifications and combinations of the embodiments may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Inspection system 1 ... LED illuminator 2 ... Illumination control power supply 21 ... Reception part 24 ... Strobe light emission width controller 25 ... Lighting ratio controller 26 ... Control period calculation Unit 27 ... lighting ratio signal output unit 28 ... multiplier

Claims (8)

An illumination control power supply for supplying power to an LED illuminator configured to be capable of strobe light emission,
A reception unit that receives a set value of a strobe emission width and a lighting ratio of the LED illuminator within the strobe emission width;
A strobe light emission width controller that outputs an ON / OFF signal in which the set value of the strobe light emission width is set as a continuous ON period, and controls the length of a period during which the LED illuminator can emit strobe light;
A lighting ratio controller that outputs an ON / OFF signal set so that the ratio of the ON period and the OFF period becomes the set value of the lighting ratio within a period in which the LED illuminator can emit strobe light, and controls the lighting ratio; ,
An ON / OFF signal from each of the strobe light emission width controller and the lighting ratio controller, and a multiplier that outputs a final output signal obtained by multiplying each ON / OFF signal to the LED illuminator. Lighting control power supply characterized by. The lighting rate controller is
A control cycle calculation unit that calculates a control cycle of 1 / integer of the set value of the strobe emission width;
The length of the ON period or the OFF period can be set for each control period calculated by the control period calculation unit, and the ratio of the sum of the ON period and the sum of the OFF period within the period in which the LED illuminator can emit strobe light The lighting control power supply according to claim 1, further comprising: a lighting ratio signal output unit that outputs an ON / OFF signal that is set to be a setting value of the lighting ratio.   The illumination control power supply according to claim 2, wherein the lighting ratio signal output unit is configured to output an ON / OFF signal in which the ratio of the ON period and the OFF period is set to the same value in a plurality of control cycles.   When the strobe emission width is equal to or smaller than a predetermined value, the control cycle calculation unit sets the time length so that a plurality of control cycles are included in the strobe emission width, and the lighting ratio signal output unit The illumination control power supply according to claim 2 or 3, wherein the ratio of the ON period and the OFF period is different from that of other control periods for at least some of the control periods.   5. The illumination control power supply according to claim 2, wherein the control cycle calculation unit is configured to calculate a control cycle having a cycle longer than a minimum pulse width that can be output from the lighting ratio signal output unit.   The illumination control power supply according to claim 2, wherein the control cycle calculation unit is configured to calculate a time length substantially ½ of the strobe emission width as the control cycle. .   The output start timing of the ON period in the ON / OFF signal output from the strobe light emission width controller is synchronized with the output start timing of the ON period of the ON / OFF signal output from the lighting ratio signal output unit. The illumination control power supply according to any one of claims 2 to 6, which is configured as follows. The lighting control power supply according to any one of claims 1 to 7,
The LED illuminator arranged so that light is irradiated to the inspection object;
A camera arranged at a position where the inspection object can be imaged;
A shutter control unit that controls opening and closing of the shutter of the camera,
The shutter control unit opens the shutter before the output start timing of the ON period of the ON / OFF signal output from the strobe light emission width controller, and closes the shutter after the output end timing of the ON period. Inspection system that is configured as follows.