JP6266455B2 - LIGHTING POWER SUPPLY DEVICE AND OVERDRIVE CURRENT CALCULATION METHOD - Google Patents

Description

  The present invention relates to an illumination power supply device and an overdrive current calculation method.

  When manufacturing a semiconductor device, die bonding for mounting a semiconductor chip (die) on a lead frame as a mounted member is performed. For this die bonding, a die bonder having a collet for adsorbing chips is used.

  As shown in FIG. 12, such a die bonder includes a bonding arm (not shown) having a collet 3 for attracting the semiconductor chip 1 of the supply unit 2 and a confirmation camera (not shown) for observing the semiconductor chip 1 of the supply unit 2. And a confirmation camera (not shown) for observing the island portion 5 of the lead frame 4 at the bonding position.

  The supply unit 2 includes a semiconductor wafer, and the semiconductor wafer is divided into a large number of semiconductor chips 1. Further, the bonding arm holding the collet 3 can be moved between the pickup position and the bonding position via the conveying means.

  Further, the collet 3 is vacuum-sucked through the suction holes opened in the lower end surface thereof, and the chip 1 is adsorbed on the lower end surface of the collet 3. If this vacuum suction (evacuation) is released, the chip 1 is detached from the collet 3.

  Next, a die bonding method using this die bonder will be described. First, the chip 1 to be picked up is observed with a confirmation camera disposed above the supply unit 2, and the collet 3 is positioned above the chip 1 to be picked up, and then the collet 3 as indicated by an arrow A. Is lowered to pick up the chip 1. Thereafter, the collet 3 is raised as shown by the arrow B.

  Next, the island portion 5 of the lead frame 4 to be bonded is observed with a confirmation camera arranged above the bonding position, and the collet 3 is moved in the direction of arrow C, and above the island portion 5. After being positioned, the collet 3 is moved downward as indicated by an arrow D, and the chip 1 is supplied to the island portion 5. In addition, after the chip is supplied to the island portion 5, the collet 3 is raised as indicated by the arrow E and then returned to the standby position above the pip-up position as indicated by the arrow F.

  That is, by moving the collet 3 sequentially as indicated by arrows A, B, C, D, E, and F, the chip 1 positioned based on the observation of the pickup confirmation camera is picked up by the collet 3. The chip 1 is mounted on the island portion 5.

  In such a die bonder, an illumination system is used for image recognition (Patent Document 1). Further, in recent years, LED lighting having excellent characteristics when it consumes less power, has a longer life, and generates less heat than a normal light bulb or fluorescent lamp is used for the lighting system. LED lighting is a lighting fixture using a light emitting diode (LED).

  When the LED lighting is turned on, a strobe power supply 10 has been conventionally used as a power supply as shown in FIG. When the LED lighting (first LED lighting 11 and second LED lighting 11 in the illustrated example) is stroboscopically illuminated, a voltage exceeding the rating (overdrive voltage: hereinafter referred to as Vover) is applied within a limited time (hereinafter referred to as tmax). It can be made brighter than applying a rated voltage (hereinafter referred to as Vnomal).

  A general strobe power supply is a constant voltage power supply as shown in FIG. 13, and a certain Vover value is determined and the strobe is turned on. When performing the same operation with a constant current power supply, it is necessary to drive the LED lights 11 and 12 with an overdrive current (hereinafter referred to as Iover) that flows when Vover is applied.

  By the way, when changing the illumination, the same Vover value may be applied if it is a constant voltage power supply. However, in the case of the constant current power supply 13 as shown in FIG. 14, LED illumination (first LED illumination and second LED illumination) is used. Iover is different. For this reason, as shown in FIG. 15, it is necessary to set the Iover individually for the LED illumination (the first LED illumination 14 and the second LED illumination 15) and perform the strobe lighting.

  As a method of performing strobe lighting, a method of fixing Iover (when the LED illumination to be used is individual), a method of setting from the outside such as manual setting by a switch or a setting of communication, a method of identifying and automatically setting the LED illumination ( For example, there is a method as shown in Patent Document 2.

JP 2001-313303 A JP 2006-351484 A

  In the method of fixing Iover, the LED illumination cannot be changed, and the device design is inferior. Further, in the method of fixing Iover and the method of setting from the outside, it is necessary to examine the value of Iover in advance. Furthermore, in the method of setting from the outside, if the Iover value is set incorrectly, the LED illumination may be damaged. In the method of identifying and automatically setting the LED illumination, an identification circuit is required on the LED illumination side, so that the LED illumination that can be used is limited.

  In view of the above problems, the present invention provides an overdrive current calculation method and an illumination power supply device that can automatically calculate an overdrive current when an overdrive voltage is reached.

  An illumination power supply device according to the present invention is an illumination power supply device connected to an LED illumination capable of applying an overdrive voltage higher than a rated voltage by lighting a strobe and a controller serving as a drive source. A constant current supply means capable of applying a normal lighting current and a strobe lighting current that enables a strobe lighting in which a lighting time is set to a predetermined value and the current value increases; Before lighting, the exploration means for exploring the current value necessary to apply the rated voltage by applying the exploration current from the constant current supply means to the illumination, and the rating that becomes the rated voltage in the exploration means After exploring the current value, the strobe lighting from the constant current supply means is repeated to calculate the overdrive current when the voltage value becomes the overdrive voltage It is obtained by a calculation unit.

  According to the illumination power supply device of the present invention, the rated current of the rated voltage can be searched for through the searching means. In addition, after exploring (calculating) the rated current, the strobe is turned on. In this case, the current to be supplied to the LED lighting is increased and the lighting is repeated. Moreover, since the voltage concerning LED illumination changes, a voltage is measured. The strobe lighting is continued until the measured voltage reaches the overdrive voltage. The current when this voltage becomes the overdrive voltage is defined as the overdrive current. Thereafter, an overdrive current is applied to the LED illumination when the strobe is lit.

  In the strobe lighting, even if the current value in one lighting time is constant or the current value in one lighting time increases sequentially, the current value in one lighting time is There may be a mixture of constant lighting and lighting in which the current value within one lighting time increases sequentially.

  The power supply device for illumination can be used for illumination for image recognition.

  The overdrive current calculation method of the present invention is an overdrive current calculation method for calculating an overdrive current that is an overdrive voltage in LED lighting capable of applying an overdrive voltage higher than a rated voltage by lighting a strobe, wherein the LED Before lighting the lighting at the rated voltage, the probe current is applied to the LED lighting to search for the rated current value necessary for applying the rated voltage, and after the search for the rated current value, the lighting time is The overdrive current when the voltage value becomes the overdrive voltage is calculated by repeating strobe lighting that is set to a predetermined value and the current value increases.

    According to the overdrive current calculation method of the present invention, before the LED lighting is turned on at the rated voltage, the search current is applied to the LED lighting and the rated current value necessary for applying the rated voltage can be searched. it can. After searching for the rated current value, the strobe lighting with the lighting time set to a predetermined value is repeated to calculate the overdrive current when the voltage value becomes the overdrive voltage.

  In the present invention, the overdrive current can be automatically calculated, and it is not necessary to check the overdrive current in advance. In addition, since it is not necessary to set the checked current as an overdrive current, the setting workability for the illumination power supply device is excellent. Moreover, a lighting failure due to an overdrive current setting error is not caused. If it is LED illumination with the same rated voltage, it can be used for various illumination devices.

  Various patterns can be selected for strobe lighting, and the overdrive current can be calculated stably.

  If the illumination power supply device of the present invention is used for illumination for image recognition, it is possible to illuminate an object to be recognized with an optimum illuminance for image recognition, and high-accuracy image recognition is possible.

It is a simplified whole block diagram of the power supply device for illumination which shows embodiment of this invention. It is a perspective view of a die bonder. It is a flowchart figure which shows the usage method of the power supply device for illumination shown in the said FIG. It is a timing chart figure for calculating overdrive current in the power supply unit for lighting. It is a timing chart figure for description of strobe lighting. It is a timing chart figure for calculating overdrive current using other strobe lighting. It is a circuit diagram of LED illumination. It is a graph which shows the electric current and voltage characteristic of LED of LED illumination. It is a graph which shows the electric current and voltage characteristic of the limiting resistance of LED illumination. It is a graph which shows the synthetic | combination voltage of LED and resistance of LED illumination. It is a flowchart figure at the time of using the limiting resistance of LED illumination for a judgment element. It is a simplified diagram showing a die bonding process. It is a simplified block diagram of the illumination system using the conventional constant voltage power supply. It is a graph which shows the relationship between a rated current, a rated voltage, an overdrive current, and an overdrive voltage. It is a simplified block diagram of the illumination system using the conventional constant current power supply.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 shows a simplified overall block diagram of an illumination system using the illumination power supply device according to the first embodiment of the present invention. This illumination system is, for example, an image confirmation of a die bonder that is an illuminated device shown in FIG. Used for. The die bonder performs die bonding for mounting the semiconductor chip (die) 21 on the lead frame 24.

  Such a die bonder includes a bonding arm 30 having a collet 23 that adsorbs the semiconductor chip (die) 21 of the supply unit 22, a confirmation camera 26 for observing the semiconductor chip 21 of the supply unit 22, and a lead frame 24 at the bonding position. And a confirmation camera 32 for observing the island portion 25.

  The supply unit 22 includes a semiconductor wafer 28 mounted and supported on a wafer support device 27. The semiconductor wafer 28 is divided into a large number of semiconductor chips 21. The collet 23 is connected to a collet holder 29, and the collet 23, the collet holder 29, and the like constitute a bonding arm 30. The bonding arm 30 can be moved between the pickup position and the bonding position via the conveying means 31. The transport unit 31 can drive the bonding arm 30 in the X, Y, θ, and Z directions.

  Further, the chip 21 is vacuum-sucked through the suction holes opened in the lower end surface of the collet 23, and the chip 21 is adsorbed on the lower end surface of the collet 23. If this vacuum suction (evacuation) is released, the chip 21 is detached from the collet 23.

  Next, a die bonding method using this die bonder will be described. First, the chip 21 to be picked up is observed with the confirmation camera 26 arranged above the supply unit 22, the collet 23 is positioned above the chip 21 to be picked up, and then the collet 23 is lowered. The lever chip 21 is picked up.

  Further, the island portion 25 of the lead frame 24 to be bonded is observed with the confirmation camera 32 disposed above the bonding position, and the collet 23 is moved onto the island portion 25 as indicated by an arrow A1. Thereafter, the collet 23 is lowered and the chip 21 is supplied to the island portion 25.

  When observing with the confirmation camera 26 at the pickup position and when observing with the confirmation camera 32 at the bonding position, an illumination system for illuminating the observation site is required. For this purpose, an illumination system including a controller 41 (hereinafter referred to as a host controller 41) as shown in FIG. 1, an illumination power supply device 42 (hereinafter referred to as a power supply device) of the present invention, and an LED illumination 43 is used. .

  As shown in FIG. 1, the power supply device 42 is connected to a host controller 41 and a plurality of lights 43. In the present embodiment, the illumination 43 is an LED illumination that is driven at a predetermined voltage (for example, 12 V), and the illumination 43 is hereinafter referred to as an LED illumination 43. The host controller 41 is configured by a personal computer, for example.

  The power supply device 42 includes a CPU (central processing unit) 45, a plurality of constant current drive circuits 46, a plurality of voltage measurement circuits 47, and a plurality of ADCs (analog-digital conversion circuits) 48. In this case, a constant current supply circuit (constant current supply means) 50 is formed to apply a current to one LED illumination 43. That is, each constant current supply circuit 50 includes a CPU 45, a constant current drive circuit 46, a voltage measurement circuit 47, an ADC 48, and the like. The constant current supply circuit 50 applies a predetermined current value to the LED illumination 43 by the constant current drive circuit 46 according to an instruction from the CPU 45. Note that the host controller 41 and the CPU 45 are connected via a communication port 51.

  The CPU 45 is provided with exploration means 52 for exploring a current value necessary to apply 12 V to the LED illumination 43 before applying the LED illumination 43 at a predetermined voltage (12 V). Yes. That is, when the exploration means 52 instructs to apply the exploration current having a minute current value (for example, 10 mA), the constant current drive circuit 46 of the constant current supply circuit 50 applies a current value of 10 mA to the LED illumination 43. The voltage measuring means 47 measures the output voltage at this time and transmits it to the exploration means 52. The exploration means 52 increases the current value sequentially until 12V is applied to the LED illumination 43 until 12V is applied to the LED illumination 43 (that is, until the voltage measurement value by the voltage measurement means 47 reaches 12V). Apply exploration current. And when 12V is applied to the LED illumination 43, the exploration means 52 uses the current value at that time as a lighting current necessary for lighting the LED illumination 43, and applies the lighting current to light the LED illumination 43. Thereby, LED43 illumination continues lighting at 12V.

  By the way, the constant current supply means 50 of this power supply device can apply a normal lighting current and a strobe lighting current to the LED illumination. For example, as shown in FIG. 5, the strobe lighting is repeated lighting and extinguishing, and lighting at an overdrive voltage (overdrive current) exceeding the rated voltage (rated current) for a short time. Is possible. For this reason, a light quantity higher than usual can be obtained. Here, the rated voltage is a voltage indicated by the rating and means a voltage limit at which the LED lighting can be safely used, and the rated current is a current indicated by the rating, and the LED This is the current limit at which lighting can be used safely. The overdrive voltage is a voltage higher than the rated voltage, and is a voltage that does not damage the LED lighting as long as the application of this voltage is within the time limit, and the overdrive current is a current that is larger than the rated current. If the current application is within the time limit, the LED illumination is not damaged. The rated voltage is called Vnomal, the overdrive voltage is called Vover, the rated current is called Inomaal, and the overdrive voltage is called Iover.

  Therefore, in the strobe lighting, as shown in FIG. 5, it is necessary to provide a restriction time (tmax) (predetermined value) at the time of lighting, and to turn off the light for a predetermined time after lighting of the restriction time (tmax) which is a predetermined value. is there. For example, the rated voltage can be set to 12V, the overdrive voltage can be set to 18V, the constraint time (tmax) can be set to 1 msec, and the fixed time can be set to 10 msec. In order to turn on the strobe light, the CPU 45 is provided with counter means 63 for controlling the restriction time and turning off the light for a fixed time.

  Further, the CPU 45 is provided with a current value calculating means 62 for calculating an overdrive current when the voltage value becomes the overdrive voltage.

  Next, a method of using the power supply device shown in FIG. 1 will be described based on a flowchart shown in FIG. 3 and a time chart shown in FIG. In this case, the rated voltage of the LED illumination 43 is 12V, and the overdrive voltage is 18V.

  First, after releasing the connection between the constant voltage power supply and the LED illumination 43 and the host controller 41 (step S1), the power supply device 42 of the present invention is connected to the LED illumination 43 and the host controller 41 (step S2). Configure the lighting system. At this time, the host controller 41 does not need to search for a current value at which a predetermined voltage (12 V) is obtained.

  When the main power supply of the lighting system is turned on and the exploration means 52 instructs the LED illumination 43 to apply a exploration current having a minute current value (for example, 10 mA) (step S3), the constant current of the constant current supply circuit 50 The drive circuit 46 applies an exploration current having a current value of 10 mA to the LED illumination 43 to light the LED illumination 43. The voltage measuring means 47 measures the output voltage at this time (step S4) and transmits it to the exploration means 52.

  At this time, the exploration means 52 determines whether or not the output voltage is smaller than 12V (step S5). If it is smaller than 12V, the exploration means 52 increases the current value until 12V is applied to the LED illumination 43 (that is, until the voltage measurement value by the voltage measurement means 47 reaches 12V) (step S6), and the LED Steps S4 to S6 are repeated until 12V is applied to the illumination 43 to apply the exploration current.

  When the applied voltage of the LED illumination 43 reaches 12V (rated voltage) (step S5), the exploration means 52 sets the current value at that time as a lighting current necessary for lighting the LED illumination 43 (step S7), and thereafter A lighting current is applied to light the LED illumination at 12V. At this time, the lighting current is a rated current and is applied by the constant current supply means 50.

  That is, as shown in FIG. 4, the current calculation process (range H <b> 1) until the current applied to the LED illumination 43 is gradually increased to reach the rated current (Inmal) is completed. Thereafter, the current is increased until the detection voltage V reaches the overdrive voltage (Vover) while the strobe is turned on.

  That is, in FIG. 3, the process proceeds from step S7 to step S8, and the strobe lighting is started. Thereafter, the process proceeds to step S9 to determine whether or not the overdrive voltage (Vover) is reached. If not, the process proceeds to step S11 and the strobe lighting is continued. That is, the strobe lighting is continued until the overdrive voltage (Vover) is reached. Specifically, the current value is increased, the strobe lighting is continued, and the voltage value is measured. If the overdrive voltage (Vover) is reached in step S9, the current at that voltage is set as the overdrive current (Iover) (step S10).

  Specifically, the strobe lighting is performed in the process of calculating Inoma within the range H2 in FIG. After the completion of the Inomal calculation process, a fixed time is left, and a current increased by a predetermined amount (for example, about 10 mA) from Inomal is applied for a constraint time (tmax). If the current is increased more than that of Inomal, the voltage applied to the LED illumination 43 changes, and the current value calculation means 62 measures the voltage at this time. Note that a step of applying a current increased by a predetermined amount (for example, about 10 mA) from Inomall is referred to as a first lighting step 71.

  After that, after a certain period of time, the second lighting step 72 is performed by applying a current increased by a predetermined amount (for example, about 10 mA) from the first lighting step 71 during the constraint time (tmax). In this second lighting step 72, the voltage is also measured.

  In this embodiment, since Vover is not yet reached in the second lighting step 72, after the second lighting step 72 is finished, a predetermined amount (for example, about 10 mA) than the second lighting step 72 during the constraint time (tmax). A second lighting step 73 is performed by applying a current increased by a predetermined amount. In this third lighting step 73, the voltage is also measured.

  In this case, the voltage V measured in the third lighting step 73 becomes the overdrive voltage (Vover), and the current at this time is the overdrive current (Iover). The voltage at this time is measured by the current value calculation means 62. Thereafter, when the strobe is lit, this overdrive current (Iover) can be used by passing it through the power supply device to the illumination system.

  Further, the strobe lighting shown in the time chart shown in FIG. 6 may be used. That is, in the strobe lighting shown in FIG. 4, the applied current is constant within one constraint time (tmax). In contrast, the first lighting step 75 shown in FIG. 6 has an increase in current. That is, in the first lighting step 75 (within tmax), the current is increased in four steps after the Inomal current is applied. Measure the voltage at each current value.

  In this case, since the overdrive voltage (Vover) is not reached in the first lighting step 75, after the first lighting step 75 is completed, the second lighting step 76 is performed by turning off the light for a predetermined time.

  In the second lighting step 76, a current increased by a predetermined amount (for example, about 10 mA) from the final current value of the first lighting step 75 is applied, and thereafter, the current is further increased by a predetermined amount (for example, about 10 mA). An increased current is applied.

  As a result, the voltage reaches the overdrive voltage (Vover), and the current at the overdrive voltage (Vover) is defined as the overdrive current (Iover).

  In this way, the illumination power supply device can search for the rated current of the rated voltage via the searching means 52. In addition, after exploring (calculating) the rated current, the strobe is turned on. In this case, the current to be supplied to the LED illumination 43 is increased and the lighting is repeated. Moreover, since the voltage concerning LED illumination 43 changes, a voltage is measured. The strobe lighting is continued until the measured voltage reaches the overdrive voltage. The current when this voltage becomes the overdrive voltage is defined as the overdrive current. Thereafter, an overdrive current is applied to the LED illumination 43 when the strobe is lit.

  Therefore, in the present invention, the overdrive current can be automatically calculated, and it is not necessary to check the overdrive current in advance. In addition, since it is not necessary to set the checked current as an overdrive current, the setting workability for the illumination power supply device is excellent. Moreover, a lighting failure due to an overdrive current setting error is not caused. If it is LED illumination with the same rated voltage, it can be used for various illumination devices.

  Incidentally, the LED illumination 43 generally comprises an LED 60 and a limiting resistor 61 connected in series with the LED 60, as shown in FIG. On the other hand, there is an LED illumination 43 that does not have such a limiting resistor 61. When the current value is increased until the voltage reaches a certain value, in the case of the LED illumination 43 that does not have the limiting resistor 61, the increase of the voltage reaches a peak, and the current may flow. For this reason, it can be said that it is preferable to determine whether the LED illumination 43 has such a limiting resistor 61 or not. When the current I flowing through the circuit of FIG. 7 is increased by ΔI and the voltage V is increased by ΔV, the resistance value r of the limiting resistor 61 can be obtained by r≈ΔV / ΔI.

  FIG. 8 shows an example of current / voltage characteristics of the LED 60 of the LED illumination 43. In this case, the current I (mA) and the voltage Vf (V) are values shown in Table 1 below. FIG. 9 shows an example of current / voltage characteristics of the limiting resistor 61 of the LED illumination 43. In this case, the current I (mA) and the voltage Vr (V) are the values shown in Table 2 below, and the resistance is as small as 0.1. This corresponds to the case where the limiting resistor 61 is not provided.

このため、図８に示す電流・電圧特性を有すると、図９に示す電流・電圧特性とを合成電圧は図１０に示す特性となる。すなわち、次の表３に示すように、電流Ｉ（ｍＡ）と電圧Ｖ（Ｖ）は、表１の値と表２の値との合成値となる。

Therefore, if the current / voltage characteristics shown in FIG. 8 are provided, the combined voltage of the current / voltage characteristics shown in FIG. 9 becomes the characteristics shown in FIG. That is, as shown in the following Table 3, the current I (mA) and the voltage V (V) are combined values of the values in Table 1 and Table 2.

制限抵抗６１の抵抗値ｒが低い場合、前記所定電圧（１２Ｖ）を掛けると、このＬＥＤ照明４３に大電流が流れ、ＬＥＤ６０が故障するおそれがある。このため、この装置では、電圧がある値（所定電圧の１２Ｖ）に達するまで、電流を上昇させた場合、制限抵抗６１が入っていない場合、電圧の上昇が頭打ちとなって、電流を流し過ぎとなる。なお、小型の照明装置では、図１０の範囲Ｈでも故障するおそれがある。

When the resistance value r of the limiting resistor 61 is low, applying the predetermined voltage (12V) may cause a large current to flow through the LED illumination 43 and cause the LED 60 to fail. For this reason, in this device, when the current is increased until the voltage reaches a certain value (predetermined voltage of 12 V), when the limiting resistor 61 is not included, the increase of the voltage reaches a peak, and the current flows excessively. It becomes. Note that a small lighting device may fail even in the range H in FIG.

  Therefore, it is preferable to determine whether the connected LED illumination 43 does not include the limiting resistor 61. For this reason, in the present invention, in order to add the resistance value of the limiting resistor 61 to the determination criterion of the determining means 55, the limiting resistor 61 includes the current value flowing through the LED illumination 43 and the voltage value at this current value. It is necessary to provide a calculation means for obtaining the resistance value. As the calculation means, the calculation means 62 may be used, or another calculation main means (not shown) different from the calculation means 62 may be provided.

  A determination method in which the resistance value of the limiting resistor 61 is added to the determination element will be described with reference to FIG. In this case, the process starts from step S3 in FIG. In step S21, the resistance value of the limiting resistor 61 is obtained. That is, when the current I is increased by ΔI and the voltage V is increased by ΔV, the resistance value r of the limiting resistor 61 can be obtained by r≈ΔV / ΔI.

  Next, in step S22, it is determined whether the resistance value r is r≈0. If r.apprxeq.0, the limiting resistor 61 is included, and the process returns to step S3 in FIG. If r.apprxeq.0 in step S22, it means that the limiting resistor 61 is not included, and the process proceeds to step S23 to stop lighting and end.

  As described above, when the resistance value of the limiting resistor 61 is set to r, it is possible to prevent the current from flowing excessively to a device that does not have the limiting resistor 61 by determining whether r≈0 or not. Damage to the erroneous LED illumination 43 can be effectively avoided.

  In this case, in the LED illumination 43, even if the current I is changed, a characteristic common to general LEDs is used that the change in the forward voltage Vf of the LED 60 is negligibly small. For this reason, the resistance value r of the limiting resistor 61 can be measured without adding remodeling or the like to the commercially available LED lighting in the market, and damage to the LED lighting 43 due to a connection error can be prevented. In addition, the apparatus is not complicated and expensive.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the number of LED illuminations 43 may be at least one. The lighting system using this power supply device is not limited to a die bonder, and can be used for various devices that require lighting, and is optimal for devices that require lighting that is lit at a preset voltage.

  Further, the current / voltage characteristics of the LED 60 of the LED illumination 43 shown in FIG. 8 and the current / voltage characteristics of the limiting resistor 61 of the LED illumination 43 shown in FIG. 9 are not limited to those in the illustrated example. For this reason, the combined voltage of the LED 60 and the limiting resistor 61 shown in FIG. 10 is not limited to the illustrated example.

  The rated voltage, overdrive voltage, constraint time (tmax), fixed time of 10 msec, etc. can be variously set according to the LED illumination used. In addition, the number of current value increases in the lighting step is also arbitrarily set, and when there are a plurality of lighting steps, even if each lighting step has the same current value increase, any number of lighting steps can be set. Only the lighting step may have the same increase in current value, and the value having the increase in current value may be different for each lighting step. In addition, if the overdrive voltage is reached within one lighting step, the lighting step may be performed once. In addition, the amount of increase in current value at each lighting step can be arbitrarily set, and the amount of increase in current value is not limited to an equal pitch. In this case, a relatively large increase in current value may be set near the rated voltage, and a small increase in current value may be set near the overdrive voltage.

  In the above embodiment, the counter unit 63 is provided in the CPU 45. However, the calculation unit 62 may be provided outside the CPU 45 and further outside the casing in which the CPU 45 is housed. In addition, when providing the counter means 63 outside, it can comprise with a personal computer (personal computer) etc.

43 LED lighting 50 constant current supply circuit (constant current supply means)
52 Exploration means 62 Calculation means

Claims (6)

A lighting power supply device connected to an LED lighting capable of applying an overdrive voltage higher than a rated voltage by lighting a strobe and a controller serving as a driving source,
Constant current supply means capable of applying a normal lighting current to the LED lighting and a strobe lighting current that enables a strobe lighting in which a lighting time is set to a predetermined value and the current value increases;
Before lighting the LED illumination at the rated voltage, the exploration means for exploring the current value required to apply the exploration current from the constant current supply means to the LED illumination to apply the rated voltage;
A current for calculating an overdrive current when the voltage value becomes the overdrive voltage by repeating the strobe lighting from the constant current supply means after searching for the rated current value that becomes the rated voltage by the search means. An illumination power supply device comprising: a value calculating means.   The lighting power supply device according to claim 1, wherein the strobe lighting has a constant current value within one lighting time.   The lighting power supply device according to claim 1, wherein in the strobe lighting, a current value within one lighting time sequentially increases.   2. The strobe lighting according to claim 1, wherein lighting in which a current value in one lighting time is constant and lighting in which a current value in one lighting time sequentially increases are mixed. Lighting power supply.   The illumination power supply device according to any one of claims 1 to 4, wherein the illumination power supply device is used for illumination for image recognition. An overdrive current calculation method for calculating an overdrive current that is an overdrive voltage in LED lighting capable of applying an overdrive voltage higher than a rated voltage by lighting a strobe,
Before lighting the LED lighting at the rated voltage, the probe lighting is applied to the LED lighting to search for a rated current value necessary for applying the rated voltage, and after the search for the rated current value, the lighting is performed. A method of calculating an overdrive current, wherein the overdrive current when the voltage value becomes the overdrive voltage is calculated by repeating strobe lighting in which time is set to a predetermined value and the current value increases.

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