JP2013148828A - Light-emitting device and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce consumption of an internal power supply and efficiently charge a main capacitor.SOLUTION: In a case where an external power supply device 400 is connected and auxiliary light (a white color LED331) is lighted after a still picture is photographed during photographing a moving image in lighting by the auxiliary light, a main capacitor 303 is charged by only boosting voltage of an external battery 401, while charging of the main capacitor 303 by boosting voltage of an internal battery 301 is prohibited, until a charging voltage VCM across the main capacitor 303 reaches a predetermined voltage VPRW. When the charging voltage VCM reaches the predetermined voltage VPRW, the main capacitor 303 is charged by the internal battery 301 and the external battery 401 together.

Description

  The present invention relates to a strobe charging technique in a case where still image shooting accompanied by light emission of a light emitting device is performed during moving image shooting with auxiliary light turned on.

  In recent years, cameras that can shoot moving images as well as still images are increasing. In the case of still image shooting, the light emitting device may be flashed and used as auxiliary light for shooting. However, in moving image shooting, it is necessary to continuously emit light as auxiliary light.

  Therefore, a white LED or the like is used as a light source as auxiliary light during moving image shooting. However, in order to use this as auxiliary light at the time of moving image shooting, it is necessary to supply power of about 1 watt (W) to 3 watt (W) with the efficiency of the current white LED.

  Therefore, a problem arises when it is necessary to perform still image strobe shooting during moving image shooting using auxiliary light and to perform strobe charging for the next still image strobe shooting while the white LED is lit.

  When large power as described above is supplied from the internal power supply by strobe charging, the auxiliary light for moving image shooting may flicker or turn off due to a decrease in the power supply of the internal power supply. In order to avoid this, it is necessary to provide a means for detecting a decrease in the power supply to reduce or temporarily stop the charging current to the light emitting device. When such a means is used, the charging time of the light emitting device is extended. On the other hand, when still image strobe shooting is frequently performed during moving image shooting, usability is improved by shortening the charging time of the light emitting device using an external power source.

  For example, Patent Literature 1 discloses a device including an internal power source that supplies power to a flash device and a modeling lamp. This device is provided with switching means for connecting either the flash device or the modeling lamp to an external power source and simultaneously disconnecting from the internal power source, and switches in conjunction with plugging.

  Patent Document 2 discloses a flash device having a boosting unit, an illuminating unit (focusing lamp), a control unit, a battery consumption state detecting unit, and an external power source determining unit. In this apparatus, when it is detected that the battery is exhausted, the internal boosting means and the lighting means are prohibited from being driven to prevent malfunction.

  Further, Patent Document 3 has a first boosted voltage by an internal battery and a second boosted voltage by an external power supply. When an external power supply is connected, the boosted voltage by the internal battery is higher than the light emission permission voltage. A strobe device with a voltage of 3 is disclosed.

Japanese Patent Laid-Open No. 61-165739 JP 2003-098577 A JP 2006-058423 A

  However, Patent Literatures 1 to 3 do not disclose a technique for performing strobe charging while performing moving image shooting using auxiliary light after performing still image shooting during moving image shooting using auxiliary light. When the main capacitor for strobe lighting can be charged with the internal power supply and external power supply, the strobe light is turned on efficiently while taking the still image while shooting the video with the auxiliary light turned on. There was room for improvement.

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a light-emitting device capable of suppressing the consumption of an internal power supply and efficiently charging a main capacitor, and a control method thereof. Is to provide.

  In order to achieve the above object, the present invention connects a light emitting unit capable of continuous light emission, a main capacitor, an internal power source for charging the main capacitor, and an external power supply device for charging the main capacitor. During moving image shooting in which the light emitting unit is turned on, including connection means, detection means for detecting a charging voltage of the main capacitor, and determination means for determining whether or not the external power supply device is connected to the connection means After the still image is taken, if the determination means determines that the external power supply device is connected to the connection means and the light-emitting unit is lit, the detection means detects it. Until the charging voltage of the main capacitor reaches a predetermined voltage, charging of the main capacitor by the internal power supply is prohibited and the external power supply device Therefore, the main capacitor is charged, and when the charging voltage reaches the predetermined voltage, control means for controlling the main capacitor to be charged by using the internal power supply and the external power supply device together is provided. And

  According to the present invention, the consumption of the internal power supply can be suppressed and the main capacitor can be charged efficiently.

1 is a configuration diagram of a camera system to which a strobe device that is a light emitting device according to an embodiment of the present invention is applied. FIG. It is a block diagram which shows the structure of this camera system. It is a block diagram which shows the detailed structure of a strobe device and an external power supply device. It is a figure which shows the oscillation operation | movement of the step-up circuit of a strobe device. It is a flowchart which shows the procedure of the imaging | photography (imaging) process performed with this camera system. FIG. 6 is a continuation flowchart of FIG. 5 of the photographing (imaging) processing. 7 is a flowchart of still image shooting processing during moving image shooting executed in step S212 of FIG. 6. It is a flowchart of the strobe charging process executed in step S320 of FIG. It is a figure which shows an example of the relationship between the charging voltage of the main capacitor by the presence or absence of utilization of an external power supply device, and charging time.

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

  FIG. 1 is a configuration diagram of a camera system to which a strobe device that is a light emitting device according to an embodiment of the present invention is applied.

  In this camera system, a replaceable lens 200 is mounted on a camera 100 that is an imaging device, and a detachable strobe device 300 and a detachable external power supply device 400 are mounted. The strobe device 300 and the external power supply device 400 are connected by a connection connector 404 that is a connection means. The strobe device 300 includes a light emitting discharge tube 307 and a white LED 331 that emits auxiliary light during moving image shooting.

  FIG. 2 is a block diagram showing the configuration of the camera system. First, the configuration of the camera 100 and the lens 200 will be described.

  The camera microcomputer 101 communicates with the lens microcomputer 201 in the lens 200, and can acquire information on the zoom position (focal length information) of the lens 200 and the current distance ring position (subject distance). The camera microcomputer 101 can determine whether the lens 200 is attached or not attached depending on whether communication with the lens 200 is possible.

  The quick return mirror 104 is moved up and down by an actuator (not shown) in response to an instruction from the camera microcomputer 101 during exposure. The quick return mirror 104 is a half mirror for guiding light to the AF optical system, and the sub mirror 115 is also retracted in conjunction with the mirror return of the quick return mirror 104.

  The photographer can check the focus and composition of the image obtained through the lens 200 by observing the focusing screen 105 through the pentaprism 114 and the finder optical system. The shutter 103 operates under the control of the camera microcomputer 101 and can freely control the exposure time of the image sensor 102. During moving image shooting, the image sensor 102 remains exposed with the quick return mirror 104 raised, the shutter 103 open.

  The image sensor 102 photoelectrically converts the image formed by the lens 200 and takes it out as an electrical signal. The A / D converter 108 converts an analog image output signal into a digital signal. At that time, conversion according to the set ISO sensitivity is performed.

  At the time of still image shooting, the image signal processing circuit 110 performs filtering processing, color conversion processing, and gamma / knee processing on the digitized image data, and outputs the result to the memory controller 122. A buffer memory 121 and a memory 120 are connected to the memory controller 122.

  The image signal processing circuit 110 also includes a D / A converter (not shown). The video signal input from the image sensor 102 or the image data input reversely from the memory controller 122 is converted into an analog signal by the D / A converter and output to the display unit 113 using liquid crystal, organic EL, or the like. Is also possible. Switching of these functions is performed by data exchange with the camera microcomputer 101, and white balance information can be output to the camera microcomputer 101. Based on the information, the camera microcomputer 101 performs white balance adjustment.

  Further, at the time of moving image shooting, an image sent from the image signal processing circuit 110 is displayed on the display unit 113 at a constant cycle.

  The image signal processing circuit 110 can also store image data in the memory 120 through the memory controller 122 without performing signal processing according to an instruction from the camera microcomputer 101. The image signal processing circuit 110 also has a compression processing function such as JPEG.

  In the case of continuous shooting, shooting data is temporarily stored in the buffer memory 121. If there is processing time, unprocessed image data is read out, and image processing or compression processing is performed by the image signal processing circuit 110, and the continuous shooting speed is read. Is raised.

  The number of continuous shots greatly depends on the size (capacity) of the buffer memory 121. Further, at the time of moving image shooting preparation, the image signal processing circuit 110 performs processing and displays the images on the display unit 113 in parallel. At the same time, calculation control of AE and AF is also performed by sensors described later. At the time of recording a moving image, the moving image is recorded in the memory 120 via the memory controller 122 in parallel.

  Further, the camera microcomputer 101 confirms the capacity of the memory 120 through the memory controller 122 based on the predicted value data of the image size corresponding to the ISO sensitivity, the image size, and the image quality set before photographing. Then, the remaining number of images that can be shot and the time during which moving images can be recorded are calculated, and the information is displayed on the display unit 113.

  At the time of still image shooting, the memory controller 122 stores the unprocessed digital image data input from the image signal processing circuit 110 in the buffer memory 121 and stores the processed digital image in the memory 120. Conversely, the memory controller 122 outputs image data from the buffer memory 121 or the memory 120 to the image signal processing circuit 110.

  A camera power source (not shown) supplies necessary power to each IC and drive system. The input unit 112 transmits its own state to the camera microcomputer 101, and the camera microcomputer 101 controls each unit according to changes in the input unit 112. The input unit 112 includes a release button (not shown). Shooting preparation or the like is performed when the release button is half-pressed, and shooting is performed when the release button is fully pressed.

  In addition to the release button, the input unit 112 is connected to switches (not shown) such as an ISO setting button, an image size setting button, an image quality setting button, an information display button, and the like, and detects the state of each switch.

  The display of the image is performed by the display unit 113 or a display unit in the finder (not shown) according to the display command of the camera microcomputer 101.

  The defocus amount used for the focus calculation is calculated by the camera microcomputer 101 using the output of the AF sensor 107. The AF sensor 107 outputs defocus information to the camera microcomputer 101, and the camera microcomputer 101 communicates with the lens 200 based on the defocus information, and focuses using the lens driving circuit 203 inside the lens 200.

  The lens driving circuit 203 is configured by a stepping motor, for example, and adjusts the focus by changing the focus lens position of the lens group 202 under the control of the lens microcomputer 201.

  The AE (photometry) sensor 106 measures the light on the focusing screen 105 and measures the luminance of the subject through the lens 200. A diaphragm control circuit 206 in the lens 200 changes the optical diaphragm 205 according to the photometric value obtained by the AE sensor 106 under the control of the lens microcomputer 201.

  Next, the configuration of the strobe device 300 will be described.

  The strobe device 300 includes a strobe microcomputer (determination unit, control unit) 310 that controls the operation of each unit, and an internal battery 301 that is an internal power source.

  The booster circuit 302 is a booster that boosts the voltage of the internal battery 301 to several hundred volts (volts) and receives signals from the strobe microcomputer 310 from the reference clock terminal (CHG_CLK) and the oscillation start signal (CHG-ON1) terminal. Start oscillation.

  The PWR circuit 332 is a control circuit including a comparator that monitors the voltage of the internal battery 301. The PWR circuit 332 detects a drop in the power supply battery voltage (the voltage of the internal battery 301) and stops the oscillation of the booster circuit 302. As will be described later, the PWR circuit 332 is also a circuit for guaranteeing the operating voltage of the auxiliary light control circuit 330 for turning on the white LED 331 that emits auxiliary light during moving image shooting.

  The main capacitor 303 is charged by the output of the booster circuit 302. The resistors 304 and 305 are resistors that divide the voltage charged in the main capacitor 303. The voltage dividing points of the resistors 304 and 305 are connected to the A / D conversion terminal (A / D) of the strobe microcomputer 310, and the divided voltage obtained by dividing the charging potential is input to the A / D conversion terminal. Thereby, the flash microcomputer 310 can grasp the charging voltage VCM of the main capacitor 303 by the resistors 304 and 305 functioning as detection means.

  The discharge tube 307 is a light emitting unit that emits flash light during still image shooting. The discharge tube 307 converts the energy charged in the main capacitor 303 into light by discharging, and irradiates the light on the subject. The trigger circuit 306 is a known trigger circuit that emits light by applying a voltage of several K (kilo) V at the start of light emission of the discharge tube 307, and a trigger voltage is applied to the discharge tube 307 by receiving a signal from the TRIG terminal of the strobe microcomputer 310. Is applied.

  The light emission control unit 308 controls the start and stop of light emission of the discharge tube 307. Generally, an insulated gate transistor or the like is used for the light emission control unit 308. The discharge tube 307 is in a conductive state at the time of light emission, and ends light emission in a non-conductive state when the flash discharge is stopped. At the time of light emission, as described above, the output voltage of the trigger circuit 306 is applied to the discharge tube 307 so that the discharge tube 307 becomes conductive. At this time, as a charging energy path of the main capacitor 303, a discharge loop is formed from the high voltage side of the main capacitor 303 → the discharge tube 307 → the light emission control unit 308 → the low voltage side (GND) of the main capacitor 303, and discharge is performed.

  The photodiode 340 serves as a sensor that receives the amount of light emitted from the discharge tube 307. The integration circuit 309 integrates the light reception current of the photodiode 340. The integration circuit 309 starts integration by receiving a signal from the INT_ST terminal from the strobe microcomputer 310 as the discharge tube 307 emits light. The output of the integration circuit 309 is output as an analog signal, and is input to the “− terminal” of the comparator 312 and the A / D converter terminal INT_AD terminal of the strobe microcomputer 310. The “+ terminal” of the comparator 312 is connected to the D / A converter output INT_DAC terminal in the flash microcomputer 310.

  The AND gate 311 is assumed to be a two-input AND gate. The output of the comparator 312 is connected to the input terminal of the AND gate 311. The other input of the AND gate 311 is connected to the FL_START terminal of the flash microcomputer 310, and the output of the AND gate 311 is input to the light emission control unit 308.

  In addition to the reflector 315, a zoom optical system 316 that changes the irradiation angle of the strobe device 300 is provided. By appropriately changing the distance between the reflector 315 incorporating the discharge tube 307 and the zoom optical system 316, it becomes possible to change the irradiation guide number and light distribution to the subject.

  The zoom drive unit 313 includes a motor that moves the reflector 315 in which the discharge tube 307 is incorporated, and the drive is performed by a signal from the ZOOM terminal of the flash microcomputer 310. This zoom drive amount is communicated from the lens microcomputer 201 to the flash microcomputer 310 as lens focal length information via the connection connector 119, the camera microcomputer 101, and the connection connector 130.

  The position detection unit 314 is configured by an encoder or the like, and detects the zoom position of the zoom optical system 316. The position detection unit 314 gives movement information to the POSI terminal of the flash microcomputer 310, and operates the motor in the zoom drive unit 313 by the required drive amount at the ZOOM terminal of the flash microcomputer 310.

  The various input units 320 are input interfaces. For example, a switch is installed on the side surface of the strobe device 300, and zoom information can be input manually.

  The display unit 321 displays each state of the strobe device 300. As described above, the white LED 331 is a light emitting unit capable of continuous light emission that emits auxiliary light during moving image shooting, and is driven by the auxiliary light control circuit 330. The white LED 331 is turned on and off by the strobe microcomputer 310 driving the auxiliary light control circuit 330 via the LED terminal.

  Next, the configuration of the external power supply device 400 will be described.

  The external power supply device 400 is electrically connected to the strobe device 300 through the connection connector 404. The external power supply apparatus 400 includes an external battery 401 that is an external power supply, a booster circuit 402, and a clock generation circuit 403. The booster circuit 402 boosts the voltage of the external battery 401 to several hundred volts. The clock generation circuit 403 receives a signal from the oscillation start signal (CHG-ON2) terminal from the strobe microcomputer 310 via the connection connector 404 and generates a reference clock.

  The booster circuit 402 receives the signal from the clock generation circuit 403 and the signal from the oscillation start signal (CHG-ON2) terminal of the strobe microcomputer 310 to start oscillation. The booster circuit 402 charges the main capacitor 303 from the terminal of the connection connector 404 via the diode 517 of the strobe device 300.

  This external power supply device 400 can be attached to and detached from the strobe device 300. The strobe microcomputer 310 can determine the mounting state (whether or not it is connected) of the external power supply device 400 by checking the check terminal (CHK) of the connection connector 404 and detecting the ground level (LOW). it can.

  FIG. 3 is a block diagram showing detailed configurations of the strobe device 300 and the external power supply device 400. In the strobe device 300, the booster circuit 302 and the PWR circuit 332 are particularly shown in detail.

  The strobe device 300 is provided with a power switch 501 for switching the strobe device 300 on and off. The PWR circuit 332 includes a comparator 502 and a reference voltage 503 (reference voltage value EPWR). The “+ terminal” of the comparator 502 is connected to the internal battery 301 and the “− terminal” is connected to the reference voltage 503. The comparator 502 outputs a low level signal when the voltage of the internal battery 301 is lower than the reference voltage 503.

  In the booster circuit 302, the resistors 504 and 505 receive a high-level charge start signal (CHG_ON1) from the strobe microcomputer 310, and a high-level potential is generated in the resistor 505. In the two-input AND logic circuits 508 and 510, one input terminal is connected to the resistor 505. The resistors 506 and 507 are connected to the output of the AND logic circuit 508, and the midpoint of these resistors is connected to the gate terminal of the switch element 511. The resistors 512 and 513 are connected to the output of the AND logic circuit 510, and the midpoint of these resistors is connected to the gate terminal of the switch element 514.

  The inverter 509 has an input terminal connected to the other end of the input terminal of the AND logic circuit 508 and an output terminal connected to the other end of the input terminal of the AND logic circuit 510.

  The transformer 515 has an intermediate tap at the primary terminal. The intermediate tap of the primary winding of the transformer 515 is connected to the positive electrode of the internal battery 301, and the other ends are connected to the drain terminals of the switch elements 511 and 514, respectively. The secondary winding of the transformer 515 is connected to the input terminal of the diode bridge 516 as shown in the figure. The output of the diode bridge 516 is connected to the positive electrode of the main capacitor 303. The other end of the diode bridge 516 is connected to the negative electrode of the main capacitor 303 and charges the main capacitor 303 by full-wave rectifying the alternating current that is the secondary output of the transformer 515. This configuration is a so-called separately excited push-pull forward converter configuration.

  The diode 517 is inserted in a loop that charges the main capacitor 303 with a high-voltage current from the external power supply device 400. Even when the terminal of the connection connector 404 of the external power supply device 400 is disconnected, the charge of the main capacitor 303 is not discharged from the high voltage terminal (HV_IN) of the connection connector 404 by the diode 517.

  The external power supply device 400 receives a charge start signal (CHG_ON2) from the strobe microcomputer 310 via the connection connector 404 and supplies it to the clock generation circuit 403 and the booster circuit 402. The number of external batteries 401 is larger than that of the internal battery 301 so that charging can be performed more rapidly, but the number of external batteries 401 may be equal to that of the internal battery 301. Here, the booster circuit 402 in the external power supply device 400 may have the same configuration as the booster circuit 302 in the strobe device 300, and is treated as an equivalent circuit in this embodiment.

  FIG. 4 is a diagram illustrating an oscillating operation of the booster circuit 302 of the strobe device 300.

  In FIG. 4, 4-A is a reference clock generated from the reference clock terminal (CHG_CLK) of the flash microcomputer 310, and generally has a frequency of about several tens of KHz. This clock signal is given to the input of the AND logic circuit 508, and the waveform whose phase is inverted is given to the input of the AND logic circuit 510 via the inverter 509.

  4-B is the output of the oscillation start signal terminal (CHG_ON1) of the flash microcomputer 310, and a high level signal is applied to the inputs of the AND logic circuits 508 and 510. Therefore, the outputs of the AND logic circuits 508 and 510 are alternately generated according to the reference clock as indicated by 4-D and 4-E, respectively.

  4-C is an output waveform of the PWR circuit 332. The PWR circuit 332 is a circuit for guaranteeing the operating voltage of the auxiliary light control circuit 330 for lighting the white LED 331. The booster circuit 302 is controlled so as not to decrease to a potential that causes the white LED 331 to flicker or turn off.

  4-G indicates the voltage of the internal battery 301. At the start of oscillation, the voltage of the internal battery 301 decreases. If there is no PWR circuit, the voltage drops as shown by a broken line at 4-G. Therefore, a PWR circuit 332 is provided, and the potential of the internal battery 301 is detected by the PWR circuit 332. When the detected voltage is lower than the reference voltage 503, the output is set to low level and the potential of the resistor 505 is lowered. The inputs of the AND logic circuits 508 and 510 connected to the resistor 505 are set to the low level, and the outputs of the AND logic circuits 508 and 510 are set to the low level.

  When the outputs of the AND logic circuits 508 and 510 become low level, the gates of the switch elements 511 and 514 become low level, the switch elements 511 and 514 are turned off, and the voltage of the internal battery 301 is restored. The output of the comparator 502 in the PWR circuit 332 becomes high level and this is repeated. Therefore, the voltage of the internal battery 301 does not decrease to the broken line, as indicated by a solid line at 4-G, and maintains the reference voltage 503 or higher.

  The frequency when the PWR circuit 332 is activated depends on the voltage drop and return speed of the internal battery 301. As shown in 4-C, 4-D, 4-E, 4-G, Therefore, it is controlled at a frequency considerably higher than the reference clock. Generally, the frequency is about several hundreds KHz.

  4-F indicates a current charged in the main capacitor 303. When there is no PWR circuit 332, a current indicated by a broken line flows in the main capacitor 303. However, since the PWR circuit 332 is provided, the flowing current is reduced as shown by the solid line by the operation.

That is, if the PWR circuit 332 is not present, the current (I0) changes depending on the charging time (t), and if the loss time at the time of switching of the AND logic circuits 508 and 510 is ignored, the current is approximately expressed by the following formula 1. Can do.
[Equation 1]
I0 = Ebat / Rloop × EXP (−t / (n × n × C × Rloop))
Ebat; voltage Rloop of internal battery 301; equivalent resistance n of charging loop including battery resistance; winding ratio of transformer 515 (= number of secondary windings / number of primary windings)
C: Capacity of Main Capacitor 303 On the other hand, the current (I1) when the PWR circuit 332 is present is Ebat−Rbat × current = PWR voltage, and I1 = (Ebat−PWR reference voltage) / Rbat, and the voltage of the PWR circuit 332 In addition, it is regulated to a substantially constant current by the battery resistance. Here, Rbat is a battery resistance.

  In 4-F and 4-G, the case where the PWR circuit 332 is not provided and the case where the PWR circuit 332 is not provided are shown superimposed with a broken line and a solid line, respectively. However, when the PWR circuit 332 is activated, the charging current is reduced and charging is performed. The time will be longer.

  Since the frequency when the PWR circuit 332 operates is considerably higher than the reference clock as described above, the loss at the ON / OFF transition time of the switch elements 511 and 514 increases in proportion to the frequency and heat As consumed.

When the battery voltage reaches a potential at which the PWR circuit 332 does not operate, an oscillation operation is performed by the reference clock. If the reference voltage value serving as a threshold value for determining whether or not the PWR circuit 332 operates is EPWR, the predetermined voltage (VPWR) on the main capacitor 303 side corresponding thereto is n = number of secondary windings / number of primary windings. Then, it is shown by the following formula 2.
[Equation 2]
VPWR = turn ratio n x EPWR
In other words, the charging voltage of the main capacitor 303 is substantially equal to the secondary voltage of the transformer 515, and a potential 1 / n times that of the main capacitor 303 is generated at both ends of the primary voltage of the transformer.

  For example, assume that the winding ratio of the transformer 515 is n = 80, and the reference voltage 503 of the PWR circuit 332 is EPWR = 2.3V. In a state where the potential of the main capacitor 303 is equal to or higher than the predetermined voltage VPWR = 184V, the voltage of the internal battery 301 does not become 2.3V or lower even when the boosting is started.

  Here, the operating resistances (Ron) of the switch elements 511 and 514 are about several milliohms to several tens of milliohms and can be ignored. Therefore, by checking the potential of the main capacitor 303, it is possible to determine whether or not PWR is applied (up and down relationship between the voltage of the internal battery 301 and the reference voltage value EPWR for operating the PWR circuit 332).

Further, as the following Equation 3, the VPWR voltage may be set higher than the winding ratio of the EPWR to give a margin to the actual EPWR voltage.
[Equation 3]
VPWR ≧ turn ratio n × EPWR
Then, the main capacitor 303 is charged by the operation of the booster circuit 302. The voltage of the main capacitor 303 is divided by resistors 304 and 305 and detected by the A / D input terminal of the flash microcomputer 310. When the detected voltage reaches a predetermined voltage VPWR, the detected voltage is kept constant so that the voltage does not increase further.

  FIG. 5 and FIG. 6 are flowcharts showing the procedure of photographing (imaging) processing executed in this camera system. This process is mainly executed by the camera microcomputer 101.

  First, the camera microcomputer 101 determines whether or not the power of the camera 100 is off in step S101. If the power is on, the process proceeds to step S102. In step S <b> 102, the camera microcomputer 101 performs various settings such as mode settings in accordance with the input from the input unit 112. Settings such as the shooting mode, moving image illumination, and use of auxiliary light are also set here.

  In step S103, the camera microcomputer 101 determines whether the shooting mode is the moving image shooting mode or the still image shooting mode. If the moving image shooting mode is set as a result of the determination, the camera microcomputer 101 proceeds to step S201 in the flowchart of FIG. 6, while if the still image shooting mode is selected, the camera microcomputer 101 proceeds to step S104. Proceed.

  In step S104, the camera microcomputer 101 measures the luminance of the subject using the AE sensor 106, and calculates the shutter speed and aperture value for obtaining proper exposure in still image shooting. In step S105, the camera microcomputer 101 detects the defocus of the subject using the AF sensor 107 and performs focus adjustment for still image shooting.

  In step S106, the camera microcomputer 101 performs various display processes. That is, the camera microcomputer 101 causes the display unit 113 to display the state set in step S102 and various setting states. The camera microcomputer 101 also checks the capacity of the memory 120 through the memory controller 122 based on the predicted value data of the image size corresponding to the ISO sensitivity, image size, and image quality set in step S102. Then, the remaining shootable number is calculated and displayed on the display unit 113. The camera microcomputer 101 further causes the display unit 113 to display the focus state detected in step S105 and the shutter speed and aperture value calculated in step S104.

  In step S107, the camera microcomputer 101 determines whether or not a release button (not shown) in the input unit 112 is half-pressed. If the release button is half-pressed, the process proceeds to step S108. The process returns to step S101.

  The camera microcomputer 101 updates the power-off timer in step S108, and in step S109, whether the release is possible and the release button (not shown) in the input unit 112 has been completely pressed (fully pressed). Is determined. If the release button is fully pressed, the camera microcomputer 101 proceeds to step S110 to capture an image, and if not fully pressed, returns the process to step S101.

  In step S110, the camera microcomputer 101 controls the quick return mirror 104 to enter the mirror-up state. At the same time, it communicates with the lens microcomputer 201 of the lens 200 and drives the aperture control circuit 206 of the lens 200 to the aperture value calculated (calculated) in step S104 to control the aperture 205.

  In step S <b> 111, the camera microcomputer 101 controls the shutter time calculated in step S <b> 104 with the shutter 103, and captures the image of the image sensor 102 into the A / D conversion unit 108. In step S112, the camera microcomputer 101 controls the quick return mirror 104 to return to the mirror-down state, communicates with the lens 200, and controls the aperture 205 to the open state via the aperture control circuit 206.

  In step S <b> 113, the camera microcomputer 101 sends a gain value for the currently set ISO value to the lens 200, adjusts sensitivity, sends an image signal to the memory controller 122, and temporarily stores the image in the buffer memory 121.

  Next, in step S114, the camera microcomputer 101 uses the R and B values used in the image signal processing circuit 110 so that the output image has an appropriate color based on the white balance information that is the output of the image signal processing circuit 110. Gain is calculated (AWB data acquisition). In step S <b> 115, the camera microcomputer 101 processes an unprocessed image stored (saved) in the buffer memory 121 when the load on the image signal processing circuit 110 is at a level at which image processing is possible, and compresses the processed image into the memory 120. Start the storing operation. At this time, in the case of a continuous shooting mode or the like, images are sequentially stored in the memory 120.

  Next, after the processing of step S115, the camera microcomputer 101 determines the number of recorded sheets in step S216 of FIG. Here, the number of storable images is calculated (determined) in the still image shooting mode, and the remaining recording time is calculated in the moving image shooting mode. In the subsequent step S217, the camera microcomputer 101 performs display processing. Here, in the still image shooting mode, the image signal processed in step S115 is sent to a liquid crystal drive circuit (not shown) and displayed on the display unit 113, and the shooting information determined in steps S104, S105, and S216 is displayed. Displayed on the unit 113. In step S217, the camera microcomputer 101 displays the photographing information on a display unit in the finder (not shown).

  In step S219, the camera microcomputer 101 considers whether there is an area that can be stored in the memory 120 and whether or not the next release is possible (capturing is possible) in consideration of an unprocessed image in the buffer memory 121. Is determined. If the result of the determination is that photography is possible, the camera microcomputer 101 returns the process to step S101, while the process proceeds to step S220 if photography is not possible.

  In step S220, the camera microcomputer 101 displays information indicating that it is determined that the photographing is not possible as a warning display on the display unit 113 and a display unit in the finder (not shown), and the process returns to step S101 in FIG.

  If the result of determination in step S101 is that the power is off, the camera microcomputer 101 turns off the display unit 113 and turns off the display unit in the viewfinder (not shown) in step S117.

  Next, in step S118, the camera microcomputer 101 waits for all image processing, compression, and memory storage to be completed, and the captured image area of the buffer memory 121 to be empty. In step S119, the camera microcomputer 101 issues an instruction to a camera power source (not shown), stops unnecessary power supply, and ends the process.

  If the result of determination in step S103 of FIG. 5 is that the video shooting mode is in effect, the camera microcomputer 101 proceeds to step S201 in the flowchart of FIG. 6 to control the quick return mirror 104 to enter the mirror-up state. In the subsequent step S202, the camera microcomputer 101 opens the shutter 103 so that the subject image is always exposed to the image sensor 102.

  In step S <b> 203, the camera microcomputer 101 detects whether the setting is made so that auxiliary light for moving image shooting (hereinafter referred to as auxiliary light) is turned on. If the setting is made to turn on the auxiliary light, the camera microcomputer 101 communicates with the flash microcomputer 310 of the flash device 300 and turns on the white LED 331 via the auxiliary light control circuit 330 in step S204. Thereafter, the process proceeds to step S205. If the setting to turn on the auxiliary light is not made, the camera microcomputer 101 advances the process to step S205 without turning on the white LED 331.

  In step S205, the camera microcomputer 101 captures the image of the image sensor 102 into the A / D conversion unit 108 at a constant cycle. At that time, the image signal processing circuit 110 performs moving image display processing and AE and AF evaluation based on the captured image, and notifies the camera microcomputer 101 to control AE (squeezing driving) and AF (focus driving). . In step S206, the camera microcomputer 101 displays the image sent from the image signal processing circuit 110 on the display unit 113 at a constant cycle.

  In step S207, the camera microcomputer 101 determines whether or not an operation for starting moving image shooting is performed, for example, by detecting whether or not a moving image shooting start button (not shown) is pressed. As a result of the determination, if the operation for starting moving image shooting has not been performed, the process returns to step S202 and waits for the moving image shooting start button to be pressed. On the other hand, if an operation to start moving image shooting is performed, the process proceeds to step S208.

  In step S208, the camera microcomputer 101 captures the image of the image sensor 102 into the A / D conversion unit 108 at a constant cycle. At that time, based on the captured image, the image signal processing circuit 110 performs display processing of the moving image and evaluation of AE and AF, which is transmitted to the camera microcomputer 101 to control AE (squeezing drive) and AF (focus drive). .

  In step S209, the camera microcomputer 101 displays the image sent from the image signal processing circuit 110 on the display unit 113 at a constant cycle. In step S <b> 210, the camera microcomputer 101 records the moving image processed image in the memory 120 through the memory controller 122 in parallel with the processing in step S <b> 209.

  In step S <b> 211, the camera microcomputer 101 determines whether or not still image shooting has been performed during moving image shooting. For example, it is determined that still image shooting has been performed when a half-press of the release button is input, and in that case, a moving image still image shooting process of FIG. 7 described later is executed in step S212. On the other hand, if there is no input from the release button, the camera microcomputer 101 advances the process to step S213.

  In step S213, the camera microcomputer 101 determines, for example, whether or not an operation for ending moving image shooting has been performed by detecting whether or not a moving image shooting end button (not shown) has been pressed. As a result of the determination, the camera microcomputer 101 returns the process to step S208 if it is not the end of the moving image shooting, and advances the process to step S214 if the moving image shooting is ended.

  In step S214, the camera microcomputer 101 closes the shutter 103 and performs rear curtain travel and mirror control. In step S215, the camera microcomputer 101 communicates with the strobe microcomputer 310, and causes the strobe microcomputer 310 to control the auxiliary light control circuit 330 to turn off the white LED 331. Thereafter, the camera microcomputer 101 advances the process to step S216. The processing after step S216 is as described above.

  FIG. 7 is a flowchart of the still image shooting process during moving image shooting executed in step S212 of FIG.

  In step S301, the camera microcomputer 101 turns off the white LED 331 when the white LED 331 is turned on so that the light of the white LED 331 does not appear in the still image.

  In step S302, the camera microcomputer 101 closes the shutter 103. In this case, since the front curtain is ahead, the rear curtain may be canceled and charged with the front curtain again. In step S303, the camera microcomputer 101 controls the quick return mirror 104 to enter the mirror-up state.

  In steps S304 to S306, the camera microcomputer 101 executes the same processing as steps S104 to S106 in FIG. In steps S307 to S313, the camera microcomputer 101 performs the same processing as steps S109 to S115 in FIG. In step S309, the camera microcomputer 101 causes the flash device 300 to emit light if necessary. If the result of determination in step S307 is that the release button (not shown) in the input unit 112 has not been fully pressed, the camera microcomputer 101 ends the moving image still image shooting processing and proceeds to step S211 in FIG. return.

  In steps S314 and S315, the camera microcomputer 101 executes the same processing as steps S216 and S217 in FIG. In steps S316 and S317, the camera microcomputer 101 executes the same processing as in steps S219 and S220 of FIG.

  If the result of determination in step S316 is that photography is not possible, the camera microcomputer 101 proceeds to step S318. Moreover, after the process of step S317, the camera microcomputer 101 advances the process to step S318.

  In step S318, the camera microcomputer 101 detects whether the setting is made to turn on the auxiliary light. If it is set to turn on the auxiliary light, in step S 319, the white LED 331 is turned on via the auxiliary light control circuit 330 by communicating with the flash microcomputer 310 of the flash device 300. Thereafter, the process proceeds to step S320. If the setting to turn on the auxiliary light is not made, the camera microcomputer 101 advances the process to step S320 without turning on the white LED 331.

  In step S320, the camera microcomputer 101 executes a strobe charging process shown in FIG. In this processing, if the main capacitor 303 needs to be charged in the strobe device 300, charging is started, and the camera microcomputer 101 returns the processing to step S211 in FIG. 6 after the moving image still image shooting processing is completed.

  FIG. 8 is a flowchart of the strobe charging process executed in step S320 of FIG. The strobe is charged through processing not only with the strobe device 300 but also with the external power supply device 400, and processing is mainly executed by the strobe microcomputer 310.

  First, in step S401, the flash microcomputer 310 determines whether or not the external power supply device 400 is connected. This can be determined based on whether or not the terminal (CHK) of the connection connector 404 is at a low level, and if it is at a low level, it is determined that the external power supply device 400 is connected. Here, it is assumed that the terminal (CHK) is pulled up inside the microcomputer.

  If the external power supply device 400 is connected as a result of the determination, the flash microcomputer 310 proceeds to step S402 to determine whether or not the white LED 331 is lit. If the white LED 331 is on, the flash microcomputer 310 advances the process to step S405.

  In step S <b> 405, the stroboscopic microcomputer 310 detects the charging voltage VCM of the main capacitor 303 by reading the divided potential of the resistors 304 and 305 with the A / D terminal of the stroboscopic microcomputer 310. Further, it is determined whether or not the charging voltage VCM is smaller than a predetermined voltage VPWR (VCM <VPWR is established).

  Here, the PWR circuit 332 is set to a substantially minimum guaranteed operating voltage (= EPWR) for the auxiliary light control circuit 330 to operate by the reference voltage 503. When the booster circuit 302 is driven to lower the reference voltage 503 or less while the auxiliary light is on, the output of the comparator 502 becomes a low level. Since the inputs of the AND logic circuits 508 and 510 become low level, the strobe microcomputer 310 stops the operation of the switch elements 511 and 514 as described above. Then, since the boosting operation of the booster circuit 302 is prohibited, it does not drop below the minimum operation guarantee voltage (= EPWR) of the auxiliary light control circuit 330.

  The potential of the main capacitor 303 when the PWR circuit 332 operates corresponds to a voltage value (predetermined voltage VPWR) that is approximately n times the winding ratio of the reference voltage value EPWR, as shown in the above formula 2.

  If it is determined in step S405 that VCM <VPWR, the stroboscopic microcomputer 310 sets the signal at the control terminal (CHG_ON1) to a low level and inhibits the operation of the booster circuit 302 that boosts the internal battery 301 in step S406. Thereby, charging of the main capacitor 303 by the internal battery 301 is prohibited.

  Next, in step S407, the stroboscopic microcomputer 310 gives an oscillation start signal (CHG_ON2) of the connection connector 404, and boosts the booster circuit 402 by the clock signal generated from the clock generator circuit 403. As a result, the main capacitor 303 is charged by the external battery 401. That is, the boosted voltage of the booster circuit 402 is charged to the main capacitor 303 from the high voltage terminal (HV_IN) of the connection connector 404 via the diode 517.

  By repeating the processes in steps S405 to S407, the external battery 401 is boosted and the main capacitor 303 is charged only by the external power supply device 400 until the charging voltage VCM of the main capacitor 303 reaches a predetermined voltage VPWR.

  When the main capacitor 303 is charged and eventually VCM ≧ VPWR is established in step S405, the flash microcomputer 310 advances the process to step S408. In step S408, the flash microcomputer 310 boosts the internal battery 301 by setting the signal of the control terminal (CHG_ON1) to a high level. Subsequently, in step S409, the stroboscopic microcomputer 310 gives an oscillation start signal (CHG_ON2) of the connection connector 404, and boosts the booster circuit 402 by the clock signal generated from the clock generator circuit 403. Thus, after charging voltage VCM reaches predetermined voltage VPWR, control is performed so that main capacitor 303 is charged by using internal battery 301 and external battery 401 together.

  In step S410, the stroboscopic microcomputer 310 determines whether or not the charging voltage VCM of the main capacitor 303 exceeds the light emission potential V_READY of the stroboscopic device 300 (VCM> V_READY is satisfied). Then, the process of returning to step S405 is repeated until VCM> V_READY. Thereby, charging of the main capacitor 303 using both the internal battery 301 and the external battery 401 is continued. Then, when VCM> V_READY is satisfied, the flash device 300 can emit light, and the flash microcomputer 310 advances the process to step S411.

  In step S411, the flash microcomputer 310 causes the display unit 321 to display a charge completion display. Next, in step S412, the stroboscopic microcomputer 310 determines whether or not the charging voltage VCM of the main capacitor 303 exceeds the full charging potential V_REG of the stroboscopic device 300 (VCM> V_REG is established).

  As a result of the determination, the stroboscopic microcomputer 310 repeats the processes of steps S414 and S412 until VCM> V_REG is established, and continues to charge the main capacitor 303. When the charging voltage VCM eventually reaches the full charging potential V_REG, the flash microcomputer 310 advances the process to step S413, completes the charging, and ends this process.

  If it is determined in step S401 that the terminal (CHK) of the connection connector 404 is at the high level and the external power supply device 400 is not connected, the flash microcomputer 310 advances the process to step S403. In step S403 in this case, the flash microcomputer 310 performs normal charging for operating the booster circuit 302 of the flash device 300. On the other hand, in step S403 when it is determined in step S401 that the external power supply device 400 is connected and in step S402 it is determined that the auxiliary light is not lit, the flash microcomputer 310 operates both the booster circuits 402 and 302. Allow normal charging to be performed.

  After step S403, in step S404, the stroboscopic microcomputer 310 determines whether or not the charging voltage VCM of the main capacitor 303 exceeds the light emission potential V_READY of the stroboscopic device 300 (VCM> V_READY is satisfied). Then, the process of returning to step S403 is repeated until VCM> V_READY. When VCM> V_READY is eventually reached, the flash microcomputer 310 advances the process to step S411.

  FIG. 9 is a diagram illustrating an example of the relationship between the charging voltage VCM of the main capacitor 303 and the charging time depending on whether or not the external power supply device 400 is used.

  In the figure, a broken line indicates a case where the main capacitor 303 is charged only by the internal battery 301 while the white LED 331 is turned on. A solid line indicates a case where the internal battery 301 and the external power supply device 400 are used in combination according to the charging voltage VCM while the white LED 331 is turned on by the strobe charging process of FIG. Here, the predetermined voltage VPWR of the main capacitor 303 is 184V, and the full charge voltage V_REG is 330V.

  In the control indicated by the solid line, the main capacitor 303 is charged only by the external power supply device 400 until the charging voltage VCM reaches 184V, and when the voltage reaches 184V, the internal battery 301 and the external battery 401 are used together. This corresponds to a case where strobe charging is performed by turning on auxiliary light using the external power supply device 400. By using the external power supply device 400, quick charging is performed and the charging time is shortened.

  On the other hand, in the control shown by the broken line, the PWR circuit 332 is operated until the charging voltage VCM reaches 184V by boosting only the internal battery 301, and when the voltage reaches 184V, the charging state is not applied. This corresponds to a case where strobe charging is performed by turning on the auxiliary light without using the external power supply device 400.

  As described above, when the strobe light emission step-up circuit 302 is driven in a state where the white LED 331 is lit, the PWR circuit is used to ensure the minimum operation guarantee voltage (= EPWR) that guarantees the lighting of the white LED 331. 332 is activated.

  When the PWR circuit 332 is operated, the switch elements 511 and 514 are turned on / off at a high frequency, so that the switch loss is increased and charging with low efficiency is performed. Therefore, problems such as wasteful consumption of the internal battery 301 and heat generation of the switch element occur.

  In particular, when the external power supply device 400 is used, the exhaustion of the internal battery 301 affects the operation of the strobe device 300, and even if the external battery 401 of the external power supply device 400 has a remaining capacity, it may become unusable.

  Therefore, in the present embodiment, inefficient consumption due to switch loss of the internal battery 301 is prevented by performing charging only with the external power supply device 400 in a state where the low-efficiency PWR circuit 332 operates. This enables efficient consumption of the internal battery 301 and quick charging of the main capacitor 303.

  According to the present embodiment, after the still image shooting is performed during the moving image shooting with the auxiliary light turned on, when the external power supply device 400 is connected and the auxiliary light is turned on, the flash microcomputer 310 Process as follows. That is, until the charging voltage VCM reaches a predetermined voltage VPRW, charging of the main capacitor 303 by the boosting of the internal battery 301 is prohibited and the main capacitor 303 is charged only by boosting of the external battery 401. When the charging voltage VCM reaches a predetermined voltage VPRW, the main capacitor 303 is charged by using the internal battery 301 and the external battery 401 together.

  Thereby, consumption of the internal battery 301 can be suppressed and the main capacitor 303 can be charged efficiently.

  The predetermined voltage VPRW is based on the minimum operation guarantee voltage (= EPWR) for operating the auxiliary light control circuit 330 and turning on the white LED 331 and the winding ratio n of the transformer 515 in the booster circuit 302. It is set (the above formula 2). Thus, the predetermined voltage VPRW can be set to a threshold value that maximizes the charging efficiency.

  Further, since the charging voltage VCM is detected by the resistors 304 and 305 that divide the voltage charged in the main capacitor 303, a simple configuration is sufficient.

  The predetermined voltage VPWR is most efficient if it is set to the value calculated by Equation 2 above, but it is not essential to set the same value as the calculated value.

  In addition, although the presence or absence of the connection of the external power supply apparatus 400 was performed with the terminal (CHK) of the connection connector 404, it does not restrict to this structure. For example, a signal for a short predetermined time may be applied to the boosting terminal (CHG_ON2) of the connection connector 404 to perform boosting, and the presence / absence of connection of the external power supply device 400 may be determined based on whether or not the charging voltage of the main capacitor 303 is increased. .

  Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included.

301 Internal Battery 302 Booster Circuit 303 Main Capacitor 304, 305 Resistor 310 Strobe Microcomputer 331 White LED
400 External power supply 404 Connection connector 515 Transformer

Claims (4)

A light emitting unit capable of continuous light emission;
A main capacitor;
An internal power supply for charging the main capacitor;
Connecting means for connecting an external power supply for charging the main capacitor;
Detecting means for detecting a charging voltage of the main capacitor;
Determination means for determining whether or not the external power supply device is connected to the connection means;
After performing still image shooting during moving image shooting with the light-emitting unit turned on, the determination unit determines that the external power supply device is connected to the connection unit, and the light-emitting unit is on Until the charging voltage of the main capacitor detected by the detecting means reaches a predetermined voltage, charging of the main capacitor by the internal power supply is prohibited and the main capacitor is charged by the external power supply device. And a light-emitting device comprising: control means for controlling the main capacitor to be charged by using the internal power supply and the external power supply device together when the charging voltage reaches the predetermined voltage.   Boosting means connected to the internal power supply and charging the main capacitor, and the predetermined voltage is a minimum operation guarantee voltage for turning on the light emitting unit and a winding ratio of a transformer in the boosting means. The light emitting device according to claim 1, wherein the light emitting device is set based on The winding ratio of the transformer is the number of secondary windings / the number of primary windings, and the predetermined voltage is the following formula:
Predetermined voltage ≥ (number of secondary windings / number of primary windings) x (minimum operation guarantee voltage)
The strobe device according to claim 2, wherein the strobe device is calculated by: A light-emitting device control method comprising: a light-emitting unit capable of continuous light emission; a main capacitor; an internal power source for charging the main capacitor; and a connecting means for connecting an external power source device for charging the main capacitor. There,
A detection step of detecting a charging voltage of the main capacitor;
A determination step of determining whether or not the external power supply device is connected to the connection means;
After performing still image shooting during moving image shooting with the light emitting unit turned on, the determination step determines that the external power supply device is connected to the connection means, and the light emitting unit is on Until the charging voltage of the main capacitor detected by the detecting step reaches a predetermined voltage, charging of the main capacitor by the internal power supply is prohibited and the main capacitor is charged by the external power supply device. And a control step of controlling to charge the main capacitor by using the internal power supply and the external power supply device together when the charging voltage reaches the predetermined voltage. .

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