JP2010134005A - Stroboscopic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stroboscopic device 1 for controlling emitted light quantity without considering crossing of component elements which participate in light emission of a flash discharge tube 2. <P>SOLUTION: The stroboscopic device 1 includes: the flash discharge tube 2; an IGBT 4 for controlling light emission of the flash discharge tube 2; and a light emission control circuit 6 for controlling the light emission of the flash discharge tube 2 by performing on/off operation of the IGBT 4. The stroboscopic device 1 includes an emitted light quantity correction means for correcting variance of emitted light quantity in light emitting time required from starting light emission of the flash discharge tube 2 until turning off the IGBT 4 by the light emission control circuit 6, to put it more concretely, correcting timing to turn off the IGBT 4 by a discharge means for varying discharge current for discharging gate charge of the IGBT 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flash discharge tube, an insulated gate bipolar transistor (hereinafter simply referred to as “IGBT”) for controlling light emission of the flash discharge tube, and light emission for controlling light emission of the flash discharge tube by turning on / off the IGBT. The present invention relates to a strobe device including a control circuit, and more particularly to a strobe device capable of correcting a light emission amount.

  In strobe shooting with strobe lighting, for example, in order to determine the strobe light amount for strobe light emission (hereinafter simply referred to as “main light emission”), an appropriate strobe light amount (hereinafter simply referred to as “pre-flash”) is used before the main light emission. The exposure is performed, and the strobe light amount of the main light emission is determined from the result, and the light amount of the light emission is controlled to be the main light strobe light amount.

  A conventional strobe device (see Patent Document 1) includes a flash discharge tube such as a xenon tube, a trigger circuit for exciting the flash discharge tube, an IGBT for controlling light emission of the flash discharge tube, and a discharge by the flash discharge tube. A main capacitor for accumulating (charging) the charge to be generated, and a light emission control circuit for controlling the light emission of the flash discharge tube by turning on / off the IGBT. Therefore, the strobe device, for example, when the IGBT connected in series with the flash discharge tube is turned on so that the collector-emitter is in a conductive state, the electric charge accumulated in the main capacitor is discharged by the flash discharge tube, Light emission from the flash discharge tube can be started. Further, when the IGBT is turned off, in which the collector-emitter is cut off, light emission from the flash discharge tube can be stopped.

However, even if the flash discharge tube starts light emission stop and the IGBT is turned off, the sealed gas in the flash discharge tube continues to emit light for a while. Accordingly, another conventional strobe device (see Patent Document 2) predicts the overrun light amount from the stop of light emission of the flash discharge tube to the complete stop of light emission, and flashes with the emitted light amount including the overrun light amount. Control was performed to stop the light emission of the discharge tube.
JP 2000-347253 A JP 2007-232864 A

  However, flash discharge tubes have variations in arc length, sealed gas pressure, etc., depending on the accuracy of manufacturing, etc. Even if they are controlled to emit light under the same conditions, there are variations in the amount of emitted light for each flash discharge tube. Will occur. Therefore, if only the overrun light quantity is taken into consideration during the light emission control of the strobe device, the actual light emission quantity becomes excessive or insufficient with respect to the planned light emission quantity, and the control becomes unstable.

  Therefore, the present invention has been made in view of the above-described conventional problems, and a strobe device capable of controlling the amount of emitted light without considering the tolerance of components involved in the light emission of the flash discharge tube. The issue is to provide.

  The strobe device according to the present invention has been made to solve the above-described problems. The flash discharge tube, the IGBT for controlling the light emission of the flash discharge tube, and the on / off operation of the IGBT to emit light from the flash discharge tube. In a strobe device having a light emission control circuit to control, the light emission control circuit takes a variation in the amount of emitted light due to the tolerance of components involved in the light emission of the flash discharge tube from the start of light emission of the flash discharge tube until the IGBT is turned off. A light emission amount correction unit capable of correcting the light emission time is provided.

  According to the strobe device having such a configuration, by correcting the light emission time from the start of light emission of the flash discharge tube until the IGBT is turned off to an appropriate time, light emission due to the tolerance of the components involved in the light emission of the flash discharge tube The variation in the amount of light can be made uniform for each strobe device manufactured. By controlling the light emission amount of the strobe device based on the light emission time after correction, it becomes unnecessary to consider the variation in the light emission amount due to the tolerance of the components involved in the light emission of the flash discharge tube. This eliminates the need for parts for reducing the size and weight of the strobe device. For example, in the assembly process at the factory, by correcting the variation in the amount of emitted light due to the tolerance of the components involved in the light emission of the flash discharge tube, the amount of emitted light is determined from other than the tolerance of this component in the post-shipment shooting. be able to.

  Further, the light emission amount correction means of the strobe device according to the present invention is configured to correct the light emission time from the start of light emission of the flash discharge tube until the IGBT is turned off by the discharge means that changes the discharge current for discharging the gate charge. Can be adopted.

  According to the strobe device having such a configuration, the discharge time of the gate charge can be changed by changing the discharge current, and the timing at which the IGBT is turned off can be changed. Therefore, depending on the tolerance of the components involved in the light emission of the flash discharge tube. Excess or deficiency in the amount of emitted light due to the variation in the amount of emitted light can be corrected by the light emission time required from the start of light emission of the flash discharge tube until the IGBT is turned off.

  Further, the light emission quantity correction means of the strobe device according to the present invention includes a delay means for delaying the start of discharge of the gate charge from the start of the light emission stop to the flash discharge tube by an analog delay circuit, and the IGBT from the start of light emission of the flash discharge tube. It is possible to employ a configuration that corrects the light emission time required for turning off.

  According to the strobe device having such a configuration, by changing the delay time of the analog delay circuit, the gate charge discharge start timing can be changed and the IGBT turn-off timing can be changed. Excess or deficiency in the amount of emitted light due to variations in the amount of emitted light due to the tolerance of the constituent elements to be corrected can be corrected by the light emission time required from the start of light emission of the flash discharge tube until the IGBT is turned off.

  In addition, the light emission amount correction means of the strobe device according to the present invention turns off the IGBT from the start of light emission of the flash discharge tube by delay means for delaying the start of discharge of gate charge from the start of light emission stop to the flash discharge tube by a digital delay circuit. It is possible to adopt a configuration that corrects the light emission time required for the operation.

  According to the strobe device having such a configuration, by changing the delay time of the digital delay circuit, the gate charge discharge start timing can be changed and the IGBT turn-off timing can be changed. Excess or deficiency in the amount of emitted light due to variations in the amount of emitted light due to the tolerance of the constituent elements to be corrected can be corrected by the light emission time required from the start of light emission of the flash discharge tube until the IGBT is turned off.

  As described above, according to the present invention, the amount of emitted light can be controlled without taking into account the tolerance of components involved in the light emission of the flash discharge tube.

Hereinafter, embodiments of a strobe device according to the present invention will be described with reference to the drawings.
(First embodiment)
First, the structure of the strobe device according to the first embodiment will be described with reference to FIG. The strobe device 1 includes a flash discharge tube 2 such as a xenon tube, a trigger circuit 3 for exciting the flash discharge tube 2, an IGBT 4 for controlling light emission of the flash discharge tube 2, and a charge discharged by the flash discharge tube 2. The main capacitor 5 to be stored (charged), the light emission control circuit 6 for controlling the light emission of the flash discharge tube 2 by turning on / off the IGBT 4, and the power supply voltage supplied from the power source Vdd to match the drive voltage of the IGBT 4 And a booster circuit 7 for boosting the voltage.

  The light emission control circuit 6 charges the IGBT 4 to turn on the light to turn on the flash discharge tube 2 and turns it on, and discharges the IGBT 4 to turn off the light to stop the light emission of the flash discharge tube 2. And gate discharge means 9.

  When the input light emission signal S is turned on, the gate charging unit 8 starts charging the gate charge of the IGBT 4 to turn on the IGBT 4 and the on / off operation of the light emission signal S. A gate charge / discharge switching circuit 11 for switching between the gate charging means 8 and the gate discharging means 9 is provided. Here, the gate charge / discharge switching circuit 11 switches to the gate charging means 8 when the light emission signal S is turned on, and switches to the gate discharge means 9 when the light emission signal S is turned off.

  Therefore, when the light emission signal S is turned on, the gate charging means 8 switches the gate charge / discharge switching circuit 11 to the gate charging circuit 10, and the gate charging circuit 10 starts charging the gate charge of the IGBT 4, and the gate voltage Vg Rises. When the gate voltage Vg exceeds the threshold value Vth, the IGBT 4 is turned on.

  When the light emission signal S to be input is turned off, the gate discharge means 9 starts discharging the gate charge of the IGBT 4 to turn off the IGBT 4 and the on / off operation of the light emission signal S. A gate charge / discharge switching circuit 11 for switching between the gate charging means 8 and the gate discharging means 9 is provided. Further, the gate discharge circuit 12 is configured to discharge the IGBT 4 in two stages for protecting the IGBT 4, and a first stage gate discharge circuit 13 for discharging the gate charge with a discharge current from the variable current source I1g; The second stage gate discharge circuit 14 for discharging the gate charge with the discharge current from the fixed current source I2g, and the first stage gate discharge circuit 13 and the second stage gate discharge circuit 14 are switched by the gate voltage Vg. A gate discharge switching circuit 15 and a gate discharge voltage comparison circuit 16 that outputs a result of comparing the gate voltage Vg and the gate reference voltage Vref are provided.

  Here, the gate discharge voltage comparison circuit 16 is a comparator or the like, and outputs if the gate voltage Vg applied to the non-inverting input terminal 16a is less than the gate reference voltage Vref applied to the reference voltage input terminal 16b. Although the potential of the terminal 16c remains at a low level, when the gate voltage Vg becomes equal to or higher than the gate reference voltage Vref, the potential of the output terminal 16c is inverted from a low level to a high level. The gate discharge switching circuit 15 switches to the first stage gate discharge circuit 13 when the output terminal 16c outputs a high level, and switches to the second stage gate discharge circuit 14 when the output terminal 16c outputs a low level. It is like that.

  Therefore, when the light emission signal S is turned off, the gate discharge means 9 switches the gate charge / discharge switching circuit 11 to the gate discharge circuit 12, and when the gate voltage Vg is higher than the gate reference voltage Vref, the gate discharge voltage comparison circuit 16 A high level is output, and the gate discharge switching circuit 15 is switched to the first-stage gate discharge circuit 13, and the gate charge is discharged by the discharge current by the gate resistor R1g. When the gate voltage Vg becomes lower than the gate reference voltage Vref, the gate discharge switching circuit 15 is switched to the second stage gate discharge circuit 14. When the gate voltage Vg is lower or lower than the gate reference voltage Vref, the gate discharge voltage comparison circuit 16 outputs a low level, the gate discharge switching circuit 15 is switched to the second stage gate discharge circuit 14, and the gate The gate charge is discharged by the discharge current generated by the resistor R2g. When the gate voltage Vg becomes lower than the threshold value Vth, the IGBT 4 is turned off.

  Furthermore, since the gate discharge means 9 selects one of the plurality of current sources I1g of the first stage gate discharge circuit 13, the discharge rate of the gate charge changes and the timing at which the IGBT 4 is turned off changes. The light emission quantity correction means can correct the timing at which the flash discharge tube 2 stops emitting light, and the first stage gate discharge circuit is a correction means.

  Next, with respect to the strobe device 1 according to the first embodiment, a method for correcting the variation in the amount of emitted light by the gate discharge means 9 of the light emission control circuit 6 after assembling each component will be described with reference to FIG.

  First, the amount of emitted light of the strobe device 1 is measured, and the amount of variation in the amount of emitted light caused by the tolerance of the components involved in the light emission of the flash discharge tube 2 is measured. The method for calculating the amount of emitted light is the same as that of the prior art, and the test light emission signal St is input to the strobe device 1 in a simulated manner to calculate the amount of emitted light. Here, the test light emission signal St is a pulse-like signal that is kept on from the start of light emission to the stop of light emission.

  First, the test light emission signal St is input to the input terminal I of the light emission control circuit 6 after assembly. When the test light emission signal St changes from the OFF state to the ON state (S0), the gate charge / discharge switching circuit 11 of the gate charging means 8 is switched to the gate charging circuit 10, and the gate charging circuit 10 charges the gate charge of the IGBT 4 (S1). . Next, the gate voltage Vg exceeds the threshold value Vth, and the IGBT 4 is turned on (S2). When the IGBT 4 is turned on, the electric charge accumulated in the main capacitor 5 flows to the trigger circuit 3, the trigger voltage is applied to the flash discharge tube 2, and the flash discharge tube 2 starts to emit light (S3).

  Next, when the test light emission signal St changes from the on state to the off state (S4), the gate charge / discharge switching circuit 11 of the gate discharge means 9 switches to the gate discharge circuit 12, and the gate discharge voltage comparison circuit 16 switches to the gate reference voltage Vref. Since the gate voltage Vg of the IGBT 4 is higher, the gate discharge switching circuit 15 is switched to the first stage gate discharge circuit 13, and the IGBT 4 is discharged by the selected current source I1g of the first stage gate discharge circuit 13 ( S5).

  Eventually, the gate voltage Vg becomes lower than the gate reference voltage Vref (S6), the gate discharge switching circuit 15 is switched to the second stage gate discharge circuit 14, and the IGBT 4 supplies the gate charge by the current source I2g of the second stage gate discharge circuit 14. It is discharged (S7).

  Further, the gate voltage Vg becomes lower than the threshold value Vth, the IGBT 4 is turned off (S8), and the flash discharge tube 2 stops emitting light (S9). In the meantime, the emitted light quantity from when the flash discharge tube 2 starts to emit light until the flash discharge tube 2 completely stops emitting light is measured by the emitted light quantity measuring device as the test emitted light quantity Qt.

Next, in order to obtain the error light amount by comparing the reference light emission amount Q and the test light emission amount Qt measured by the light emission amount measurement device, the flash discharge tube is used to match the test light emission amount Qt and the reference light emission amount Q. 2 emission time Tr is corrected. Specifically, when the test light emission amount Qt is larger than the reference light emission amount Q and the light emission is excessive, the current source I1g of the first stage gate discharge circuit 13 is reduced to increase the discharge rate of the gate charge of the IGBT 4, thereby causing the flash discharge. The light emission time Tr of the tube 2 is shortened.
The light emission amount corresponding to the error light amount is reduced by the shortened light emission time, and the test light emission amount Qt and the reference light emission amount Q coincide with each other.

  Further, when the test light emission quantity Qt is less than the reference light emission quantity Q and the light emission is insufficient, the current source I1g of the first stage gate discharge circuit 13 is increased and the discharge rate of the gate charge of the IGBT 4 is lowered to reduce the emission of the flash discharge tube 2. The time Tr is extended to make the test light emission quantity Qt and the reference light emission quantity Q coincide.

  Which of the plurality of current sources I1g of the first-stage gate discharge circuit 13 corrected in this way is selected is recorded in the EEPROM which is a nonvolatile memory.

  Therefore, once an optimum one is selected from the plurality of current sources I1g of the first stage gate discharge circuit 13 once assembled, the light emission quantity of the strobe device 1 after the next time is corrected. The current source I1g can perform gate discharge and can match the target strobe light amount in both pre-light emission and main light emission, so that the light emission amount caused by the tolerance of the components involved in the light emission of the flash discharge tube No variation occurs.

This completes the description of the strobe device 1 according to the first embodiment. Next, a strobe device according to the second embodiment will be described with reference to FIG. In addition, the gate discharge circuit 12 according to the first embodiment discharges the IGBT 4 in two stages to protect the IGBT 4, but in the second embodiment, the delay time of the analog delay circuit 20 is adjusted. For example, the IGBT 4 can be discharged in one stage. In addition, about the part similar to the flash device 1 which concerns on 1st embodiment, the same code | symbol shall be attached and description shall be abbreviate | omitted.
(Second embodiment)
First, the structure of the strobe device 17 according to the second embodiment will be described. The light emission control circuit 18 according to the second embodiment includes a gate charging unit 8, a gate discharge circuit 19 that discharges the IGBT 4 to stop light emission to stop the flash discharge tube 2, and an input light emission signal S. An analog delay circuit 20 that delays output to the gate discharge circuit 19 is provided. Since the gate discharge circuit 19 does not perform two-stage discharge, it is not necessary to divide into two stages unlike the gate discharge circuit 12 according to the first embodiment, and the first-stage gate discharge circuit 13 and the gate discharge switching circuit are not required. 15 and the gate discharge voltage comparison circuit 16 are not provided. The analog delay circuit 20 delays and outputs the input light emission signal S using, for example, the time required to charge and discharge the capacitor, and includes a delay circuit capacitor and a delay circuit. It has a plurality of resistors. Therefore, when the light emission signal S is turned off, the analog delay circuit 20 can select one of a plurality of resistors for the delay circuit and delay the time required for charging the capacitor for the delay circuit. The light emission amount correction means can change the delay time by the selected resistance, and the plurality of resistance values for the delay circuit are delay means.

  Next, with respect to the strobe device 17 according to the second embodiment, a method of correcting the variation in the amount of emitted light by the analog delay circuit 20 of the light emission control circuit 18 after assembling each component will be described with reference to FIG. As in the first embodiment, first, the amount of light emitted by the strobe device 17 is measured, and the amount of variation in the amount of light emitted due to the tolerance of the components involved in the light emission of the flash discharge tube 2 is simulated in the strobe device 17. Assume that the test light emission signal St is inputted and the amount of emitted light is calculated.

  First, the test light emission signal St is input to the input terminal I of the light emission control circuit 18 after assembly. When the test light emission signal St changes from the OFF state to the ON state (S0), the gate charge / discharge switching circuit 11 of the gate charging means 8 is switched to the gate charging circuit 10, and the gate charging circuit 10 is charged with the gate charge of the IGBT 4 (S1). ). Next, the gate voltage Vg exceeds the threshold value Vth, and the IGBT 4 is turned on (S2). When the IGBT 4 is turned on, the electric charge accumulated in the main capacitor 5 flows to the trigger circuit 3, the trigger voltage is applied to the flash discharge tube 2, and the flash discharge tube 2 starts to emit light (S3).

  Next, when the test light emission signal St changes from the on state to the off state (S4), the test light emission signal St is input to the analog delay circuit 20, and the capacitor for the delay circuit is charged with the charging current by the variable resistor for the delay circuit. (S5). When charging of the capacitor for the delay circuit is completed, a test light emission signal St is output to the gate discharge circuit 19 (S6). Then, the test light emission signal St is input to the gate discharge circuit 19, the gate charge / discharge switching circuit 11 of the gate discharge circuit 19 is switched to the gate discharge circuit 12, and the gate voltage Vg is changed by the gate resistance R2g of the second stage gate discharge circuit 14. The gate charge of the IGBT 4 is discharged (S7).

  Further, the gate voltage Vg becomes lower than the threshold value Vth, the IGBT 4 is turned off (S8), and the flash discharge tube 2 stops emitting light (S9). In the meantime, the emitted light quantity from when the flash discharge tube 2 starts to emit light until the flash discharge tube 2 completely stops emitting light is measured by the emitted light quantity measuring device as the test emitted light quantity Qt.

  Next, in order to obtain the error light amount by comparing the reference light emission amount Q and the test light emission amount Qt measured by the light emission amount measurement device, the flash discharge tube is used to match the test light emission amount Qt and the reference light emission amount Q. 2 emission time Tr is corrected. Specifically, when the test light emission amount Qt is larger than the reference light emission amount Q and excessive light emission, a resistor having a small value for the delay circuit of the analog delay circuit 20 is selected, and the charge accumulated in the capacitor for the delay circuit is selected. The delay time of the light emission signal S is shortened by increasing the discharge speed. The light emission amount corresponding to the error light amount is reduced by the shortened light emission time, and the test light emission amount Qt and the reference light emission amount Q coincide with each other.

  When the test light emission quantity Qt is less than the reference light emission quantity Q and the light emission is insufficient, a resistor having a large value for the delay circuit of the analog delay circuit 20 is selected, and the discharge rate of the electric charge stored in the capacitor for the delay circuit is selected. By lowering and extending the delay time of the light emission signal S, the test light emission quantity Qt and the reference light emission quantity Q are matched.

  Which of the plurality of resistors for the delay circuit of the analog delay circuit 20 corrected in this way is selected is recorded in the EEPROM which is a nonvolatile memory.

  Therefore, once an optimum resistor is selected from a plurality of resistors for the delay circuit of the analog delay circuit 20 once assembled, the light emission quantity of the strobe device 1 from the next time onward is selected for the delay circuit of the analog delay circuit 20. The gated discharge can be performed by the resistance, and it can be matched with the target strobe light amount in both the pre-light emission and the main light emission, so that the light emission light amount caused by the tolerance of the components involved in the light emission of the flash discharge tube can be reduced. Variation does not occur.

This completes the description of the strobe device 17 according to the second embodiment. Next, a strobe device according to the third embodiment will be described with reference to FIG. In addition, about the part similar to strobe device 1 and 17 which concerns on 1st and 2nd embodiment, the same code | symbol shall be attached and description shall be abbreviate | omitted.
(Third embodiment)
First, the structure of the strobe device 21 according to the third embodiment will be described. The light emission control circuit 22 according to the third embodiment includes an IGBT driver 23 that controls charging and discharging of the gate charge of the IGBT 4 that hits the gate charging unit 8 and the gate discharging unit 9 in the second embodiment, and an input light emission signal S. And a digital delay circuit 24 that delays output to the IGBT driver 23.

  The digital delay circuit 24 includes a signal delay unit 25 that delays the timing of stopping the light emission, and a signal receiving unit 26 that determines the start and stop of light emission from the on / off state of the light emission signal S.

  The signal delay unit 25 includes an oscillation circuit 27 that oscillates a high-frequency clock, a pulse counter circuit 28 that counts clock pulses, and a count value comparison circuit 29 that outputs when the count value reaches the reference count value. Communication is possible with the EEPROM 30 in which the initial value or the correction value is stored.

  Here, the pulse counter circuit 28 has an input terminal for inputting the on / off state from the oscillation circuit 27, an output terminal for outputting the on / off state to the count value comparison circuit 29, and a reset terminal for resetting the count value. The light emission signal S is also directly input to the reset terminal, and the count value is reset each time the light emission signal S is turned on. The EEPROM 30 includes an output terminal that outputs a reference count value to the count value comparison circuit 29 and an input / output terminal that can input and output the count value from the outside, and the count value can be rewritten from the outside. ing. In the present embodiment, 5 is input as the count value as an initial value.

  Note that the oscillation circuit 27 may increase the accuracy of the delay time by setting the oscillation frequency high.

  When the input light emission signal S is turned on, the signal receiving unit 26 is turned on and output to the IGBT driver 23. When the input light emission signal S is turned off, the signal reception unit 26 is turned on and the signal delay unit 26 is turned on. Until the ON state is output from the signal delay unit 25, the signal is continuously output to the IGBT driver 23. When the signal delay unit 25 is turned ON, the signal delay unit 25 is turned OFF and output to the IGBT driver 23. It is configured as follows.

  For example, the signal receiving unit 26 outputs an OR circuit 31 that outputs the logical sum of the logical negation of the signal delay unit 25 and the light emission signal S to the IGBT driver 23, and the logical negation of the light emission signal S and the logic of the signal delay unit 25. An AND circuit 32 that outputs a logical product of the negative signal to the oscillation circuit 27, a first NOT circuit 33 that outputs a logical negation of the light emission signal S to the AND circuit 32, and a signal delay unit to the OR circuit 31 and the AND circuit 32. And a second NOT circuit 34 that outputs 25 logic negations.

  Therefore, when the light emission signal S is turned on, the light emission control circuit 22 turns on the OR circuit 31 and outputs an on state to the IGBT driver 23.

  Further, when the light emission signal S is turned off, the light emission control circuit 22 turns off the input terminal of the OR circuit 31 connected to the input terminal I, so that the OR circuit 31 depends on the output state of the second NOT circuit 34. The output state of changes. First, in the count value comparison circuit 29, since the output state of the AND circuit 32 is OFF, the oscillation circuit 27 does not oscillate, the count value of the pulse counter circuit 28 remains zero, and the reference count value Unlike the certain 5, it is in the off state. Since the output state of the count value comparison circuit 29 is logically negated by the second NOT circuit 34 and turned on, the AND circuit 32 is turned on. Therefore, the input terminal of the oscillation circuit 27 is turned on, the oscillation circuit 27 oscillates, and the result of counting the number of oscillation pulses of the oscillation circuit 27 by the pulse counter circuit 28 is input to the count value comparison circuit 29. The count value comparison circuit 29 compares it with the reference count value of the EEPROM 30, and outputs the same to the second NOT circuit 34 if they match. The second NOT circuit 34 is logically negated and turned off, and the input terminal of the OR circuit 31 is turned off, so that the output state of the OR circuit 31 is turned off. Therefore, the input of the IGBT driver 23 is turned off.

  Furthermore, the digital delay circuit 24 is a light emission quantity correction unit that can change the delay time input to the IGBT driver 23 by changing the number of oscillation pulses of the oscillation circuit 27 by rewriting the reference count value of the EEPROM 30. The signal delay unit 25 is a delay unit.

  Next, with respect to the strobe device 21 according to the third embodiment, a method of correcting the variation in the amount of emitted light with the digital delay circuit 24 of the light emission control circuit 22 after assembling each component will be described with reference to FIG. As in the first and second embodiments, first, the amount of emitted light of the strobe device 21 is measured, and the amount of variation in the amount of emitted light caused by the tolerance of the constituent elements involved in the light emission of the flash discharge tube 2 is determined. It is assumed that a test light emission signal St is input to 21 to calculate the light emission quantity.

  First, the test light emission signal St is input to the input terminal I of the light emission control circuit 22 after assembly. When the test light emission signal St changes from the off state to the on state (S0), the test light emission signal St is input to the OR circuit 31, the output state is turned on, input to the IGBT driver 23, and the gate charge of the IGBT 4 is charged (S1). Next, the gate voltage Vg exceeds the threshold value Vth, and the IGBT 4 is turned on (S2). When the IGBT 4 is turned on, the electric charge accumulated in the main capacitor 5 flows to the trigger circuit 3, the trigger voltage is applied to the flash discharge tube 2, and the flash discharge tube 2 starts to emit light (S3).

  Next, when the test light emission signal St changes from the on state to the off state (S4), since the output state of the AND circuit 32 is the off state, the oscillation circuit 27 does not oscillate, and the count value of the pulse counter circuit 28 Remains zero, and the count value comparison circuit 29 does not match the reference count value, so that the output state of the count value comparison circuit 29 is turned off. Therefore, the input terminal of one AND circuit 32 connected to the second NOT circuit 34 is turned on because the logical value of the count value comparison circuit 29 in the off state is negated by the second NOT circuit 34, and the first NOT circuit 34 is turned on. The input terminal of the other AND circuit 32 connected to the circuit 33 is turned on because the test light emission signal St in the off state is logically negated by the first NOT circuit 33, and the output state of the AND circuit 32 is turned on. It becomes a state. Therefore, the oscillation circuit 27 is turned on, the output state of the oscillation circuit 27 oscillates, the number of pulses of the oscillation circuit 27 is counted by the pulse counter circuit 28, and the result is input to the count value comparison circuit 29 (S5). ). The count value comparison circuit 29 compares it with the reference count value of the EEPROM 30, and keeps the output state off until they match, and when they match, it sets the output state to on and outputs it to the second NOT circuit 34 (S6). The logic is negated by the second NOT circuit 34 to turn off, and one input terminal of the OR circuit 31 is turned off. At this time, since the other input terminal connected to the input terminal I of the OR circuit 31 is in an off state, the output state of the OR circuit 31 is in an off state. Therefore, the input of the IGBT driver 23 is turned off, and the gate charge of the IGBT 4 is discharged (S7).

  Eventually, the gate voltage Vg becomes lower than the threshold value Vth, the IGBT 4 is turned off (S8), and the flash discharge tube 2 stops emitting light (S9). In the meantime, the emitted light quantity from when the flash discharge tube 2 starts to emit light until the flash discharge tube 2 completely stops emitting light is measured by the emitted light quantity measuring device as the test emitted light quantity Qt.

  Next, in order to obtain the error light amount by comparing the reference light emission amount Q and the test light emission amount Qt measured by the light emission amount measurement device, the flash discharge tube is used to match the test light emission amount Qt and the reference light emission amount Q. 2 emission time Tr is corrected. Specifically, when the test light emission amount Qt is larger than the reference light emission amount Q and the light emission is excessive, the correction value of the reference counter value recorded in the EEPROM 30 is reduced, the number of oscillations of the oscillation circuit 27 is reduced, and the light emission signal S Is shortened, the light emission time Tr of the flash discharge tube 2 is shortened.

  The light emission time Tr of the flash discharge tube 2 is shortened by the shortened light emission time, the light emission amount corresponding to the error light amount is reduced, and the test light emission amount Qt and the reference light emission amount Q coincide.

  When the test light emission amount Qt is less than the reference light emission amount Q and the light emission is insufficient, the reference counter value correction value recorded in the EEPROM 30 is increased, the number of oscillations of the oscillation circuit 27 is increased, and the delay time of the light emission signal S is increased. Is extended, the light emission time Tr of the flash discharge tube 2 is extended, the light emission amount corresponding to the error light amount is increased, and the test light emission amount Qt and the reference light emission amount Q are matched.

  The reference counter value corrected in this way is recorded in the EEPROM 30 which is a nonvolatile memory.

  Therefore, once the reference counter value is corrected after assembly, the light emission quantity of the strobe device 21 from the next time onward can be subjected to gate discharge according to the corrected reference counter value. Since the amount of light can be matched, the amount of emitted light does not vary due to the tolerance of the components involved in the light emission of the flash discharge tube.

  The strobe device according to the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention.

  For example, regarding the gate discharge of the IGBT 4 according to the present invention, the example in which the discharge is performed in two stages in the first embodiment and the example in which the discharge is performed in one stage in the second and third embodiments have been described. Instead, it can be changed according to the IGBT4.

  In the photographing apparatus equipped with the strobe device according to the present invention, not only at the time of manufacture, but also in response to a change in the amount of emitted light that occurs in the flash discharge tube due to use, the photographing device is connected to an adjustment device or the like, When the number of times of light emission reaches a predetermined number, the amount of emitted light is measured again by the emitted light amount measuring device to correct the excess or deficiency of the emitted light amount, and the light emission control can be stabilized.

  Also, with regard to the components involved in the light emission of the flash discharge tube, due to variations in accuracy such as the difference in the enclosed gas pressure, the flash light discharge tube or the flash discharge tube in which the amount of emitted light may vary for each manufactured component It is effective even when the required amount of light cannot be secured due to manufacturing tolerances in reflectivity and reflection angle, etc., and it also includes components related to the light emission path of the flash discharge tube such as a reflector. Can do.

  The strobe device according to the present invention can be applied to applications such as technical fields where it is necessary to control the amount of emitted light without taking into account the tolerances of the components involved in the light emission of the flash discharge tube.

1 is a block diagram showing a circuit configuration of a strobe device 1 according to a first embodiment. FIG. 1 is a strobe device 1 according to a first embodiment, where (a) a diagram showing a waveform of a light emission signal S (test light emission signal St), and (b) a diagram showing a waveform of a gate voltage Vg. The block diagram which shows the circuit structure of the flash device 17 which concerns on 2nd embodiment. The strobe device 17 according to the second embodiment, (a) a diagram showing the waveform of the light emission signal S (test light emission signal St), (b) a diagram showing the waveform of the light emission signal S after passing through the analog delay circuit 20, And (c) a diagram showing a waveform of the gate voltage Vg. The block diagram which shows the circuit structure of the flash device 21 which concerns on 3rd embodiment. In the strobe device 21 according to the third embodiment, (a) a diagram illustrating a waveform of the light emission signal S (test light emission signal St), (b) a diagram illustrating an output waveform of the AND circuit 32, and (c) an oscillation circuit 27. (D) shows the output waveform of the pulse counter circuit 28, (e) shows the output waveform of the count value comparison circuit 29, and (f) shows the output waveform of the light emission control circuit 22. (G) The figure which shows the waveform of gate voltage Vg

Explanation of symbols

1, 17, 21 Strobe device 2 Flash discharge tube 4 IGBT
6, 18, 22 Light emission control circuit 8 Gate charging means 9, 19 Gate discharge means 20 Analog delay circuit 23 Digital delay circuit Vg Gate voltage S Light emission signal Tr Light emission time

Claims (5)

In a strobe device comprising a flash discharge tube, an IGBT for controlling the light emission of the flash discharge tube, and a light emission control circuit for controlling the light emission of the flash discharge tube by turning on and off the IGBT, the light emission control circuit is connected to the flash discharge tube. A strobe device comprising: a light emission amount correction unit capable of correcting a variation in a light emission amount caused by a tolerance of a component involved in light emission based on a light emission time required from the start of light emission of the flash discharge tube until the IGBT is turned off. The strobe device according to claim 1, wherein the light emission quantity correction means corrects the light emission time from the start of light emission of the flash discharge tube until the IGBT is turned off by the discharge means which makes the discharge current for discharging the gate charge variable. The light emission amount correction means corrects the light emission time from the start of the light emission of the flash discharge tube to the turning off of the IGBT by the delay means for delaying the start of the discharge of the gate charge by the analog delay circuit from the start of the light emission stop to the flash discharge tube. The strobe device according to claim 1. The light emission amount correction means corrects the light emission time from the start of light emission of the flash discharge tube to the turning off of the IGBT by delay means for delaying the start of discharge of the gate charge by the digital delay circuit from the start of light emission stop to the flash discharge tube. The strobe device according to claim 1. An imaging device comprising the strobe device according to claim 1.

Images