JP2012063600A - Imaging apparatus, light-emitting device, and camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform charging operation in which irregularity of luminance of auxiliary light used for taking a moving image is restricted.SOLUTION: A maximum value of charge current in charging operation for a main capacitor (417) when illuminating an LED(325) is controlled to be smaller than a maximum value of charging current when the LED (325) is not illuminated.

Description

  The present invention relates to a light emitting device capable of flash emission and continuous emission, and more particularly to control during a charging operation for performing flash emission.

  2. Description of the Related Art Conventionally, some imaging devices such as digital cameras perform photographing by irradiating a subject with auxiliary light from a light emitting device when the subject brightness is low. In such a light emitting device, a xenon tube, an LED, or the like is used as a light source for irradiating auxiliary light.

  Patent Document 1 proposes a flash light emitting device that includes a xenon tube for normal photography and an LED for close-up photography as illumination means.

Japanese Patent Laid-Open No. 10-206942

  However, the flash light emitting device described in Patent Document 1 has the following problems when the LED is turned on as auxiliary light for moving image shooting. If the main capacitor for causing the xenon tube to emit light is lit while the LED for moving image shooting is turned on, the current supplied to the LED decreases because the main capacitor and the LED share the power source. As a result, the brightness of the LEDs varies, and the brightness becomes uneven and a suitable moving image cannot be obtained.

  The present invention has been made in view of the above problems, and an object of the present invention is to perform a charging operation in which variation in luminance of auxiliary light used for moving image shooting is suppressed.

  In order to achieve the above object, a light-emitting device according to the present invention is a light-emitting device that emits light from a first light-emitting unit that performs flash emission and a second light-emitting unit that performs continuous light emission using the same power source. , A capacitor for accumulating charges for causing the first light emitting means to emit light using the power source, and a control means for controlling the light emitting operation of the second light emitting means or the charging operation for accumulating charges in the capacitor. And the control means is configured to charge the battery when the maximum value of the charging current in the charging operation when the second light emitting means is emitting light is not causing the second light emitting means to emit light. Control is performed so as to be smaller than the maximum value of the current.

  In order to achieve the above object, an imaging apparatus according to the present invention includes a light emitting device that emits light from a first light emitting unit that performs flash emission and a second light emitting unit that performs continuous light emission using the same power source. An image pickup apparatus comprising: a capacitor that accumulates electric charges for causing the first light emitting unit to emit light using the power source; and a light emitting operation of the second light emitting unit, or an electric charge that is accumulated in the capacitor. Control means for controlling the charging operation, wherein the control means emits light from the second light emitting means when the maximum value of the charging current in the charging operation when the second light emitting means is caused to emit light. Control is performed so as to be smaller than the maximum value of the charging current when the charging is not performed.

  In order to achieve the above object, a camera system according to the present invention includes a light emitting device that emits light from a first light emitting unit that performs flash light emission and a second light emitting unit that performs continuous light emission using the same power source. A camera system including an imaging device that emits light by emitting light from the light emitting device, the capacitor storing charge for causing the first light emitting means to emit light using the power source, and the second light emission Control means for controlling a light emitting operation of the means or a charging operation for accumulating electric charge in the capacitor, and the control means performs charging in the charging operation when the second light emitting means is caused to emit light. Control is performed such that the maximum value of the current is smaller than the maximum value of the charging current when the second light emitting means is not emitting light.

  According to the present invention, it is possible to obtain a suitable moving image that does not cause unevenness in brightness by performing a charging operation that suppresses variations in luminance of auxiliary light used for moving image shooting.

1 is a block diagram showing a configuration of a camera system according to an embodiment of the present invention. Operation Timing Diagram in Camera System of Embodiment 1 FIG. 3 is an electric circuit diagram of an auxiliary light emitting unit in the camera system according to the embodiment of the present invention. Electrical circuit diagram of charging circuit in camera system of embodiment 1 Electric circuit diagram of charging circuit in camera system of embodiment 2 Operation Timing Diagram of Charging Circuit in Camera System of Embodiment 1 Operation Timing Diagram of Charging Circuit in Camera System of Embodiment 2 Operation Timing Diagram in Camera System of Embodiment 2 Operation Timing Diagram in Camera System of Embodiment 3 The flowchart figure at the time of imaging | photography in the camera system which concerns on the Example of this invention. The flowchart figure at the time of imaging | photography in the camera system which concerns on the Example of this invention. The flowchart figure of the process at the time of the video recording in the camera system which concerns on the Example of this invention. Flowchart diagram of charging operation in the camera system of Embodiment 1. Flowchart diagram of charging operation in the camera system of Embodiment 1.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing a configuration of a camera system (consisting of an imaging device, a lens unit, and a light emitting device) according to Embodiment 1 of the present invention. Reference numeral 100 denotes a camera body of a digital camera that is an imaging device, 200 denotes a lens unit, and 300 denotes a strobe device that is a light emitting device.

  First, the configuration inside the camera body 100 will be described. Reference numeral 101 denotes a microcomputer CCPU (hereinafter referred to as camera microcomputer) that controls each part of the camera body 100. Reference numeral 102 denotes an image sensor such as a CCD or CMOS including an infrared cut filter, a low-pass filter, and the like, and an image of a subject is formed at the time of photographing by a lens group 202 described later. Reference numeral 103 denotes a shutter, which is closed when not photographing and shields the image sensor 102, and is opened when photographing and guides light to the image sensor 102. A main mirror (half mirror) 104 reflects a part of light incident from the lens group 202 when not photographing, and forms an image on a focusing plate 105.

  Reference numeral 106 denotes a photometric circuit, and a photometric sensor in the circuit divides the imaging screen into a plurality of photometric areas and performs photometry in each photometric area. Reference numeral 107 denotes a focus detection circuit. The distance measuring sensor in the circuit is provided with a plurality of distance measuring points on the imaging screen, and the distance measuring point is provided at a position corresponding to the light measuring area of the light measuring sensor.

  Reference numeral 108 denotes a gain switching circuit for switching a gain for amplifying a signal output from the image sensor 102. The gain is switched by the camera microcomputer 101 according to shooting conditions, a photographer's input, and the like. Reference numeral 109 denotes an A / D converter that converts an amplified analog signal from the image sensor 102 into a digital signal. Reference numeral 110 denotes an amplified signal input from the image sensor 102 and the conversion timing of the A / D converter 109 synchronized with each other. The timing generator (TG). A digital signal processing circuit 111 performs image processing on image data converted into a digital signal by the A / D converter 109 according to parameters.

  SC is a signal line for an interface between the camera body 100, the lens unit 200, and the strobe device 300. For example, the camera microcomputer 101 is used as a host to exchange data and transmit commands to each other. Thus, communication such as a light emission start signal to the strobe device 300 is enabled. Similarly, SC is an interface with a lens microcomputer 201 to be described later, has a terminal for transmitting data from the lens microcomputer 201 to the camera microcomputer 101, and enables communication between the camera microcomputer 101 and the lens microcomputer 201.

  Reference numeral 112 denotes an input unit for inputting various types of information. The input unit 112 can input gain settings of the image sensor 102, and can input camera settings and the like using switches and buttons. Reference numeral 113 denotes a display unit including a liquid crystal device, a light emitting element, and the like that displays various set modes and other shooting information.

  A pentaprism 114 guides the subject image on the focusing plate 105 to a photometric sensor in the photometric circuit 106 and an optical viewfinder (not shown). Reference numeral 115 denotes a sub-mirror that guides a light beam incident from the lens group 202 and transmitted through the main mirror 104 to the distance measuring sensor of the focus detection circuit 107.

Next, the configuration and operation within the lens unit 200 will be described.
Reference numeral 201 denotes a microcomputer LPU (hereinafter referred to as a lens microcomputer) that controls the operation of each part of the lens unit 200. A lens group 202 includes a plurality of lenses. Reference numeral 203 denotes a lens driving circuit that moves an optical system for focusing the lens group 202. The driving amount of the lens group 202 is stored in the camera microcomputer 101 based on the output of the focus detection circuit 107 in the camera body 100. Is calculated. An encoder 204 detects the position of the lens group 202. The calculated driving amount is communicated from the camera microcomputer 101 to the lens microcomputer 201, and the lens microcomputer 201 operates the lens driving circuit 203 by the driving amount according to the driving information of the encoder 204 to move the lens group 202 to the in-focus position. Reference numeral 205 denotes a stop, 206 denotes a stop control circuit, and the stop 205 is controlled by the lens microcomputer 201 via the stop control circuit 206.

Next, the configuration of the strobe device 300 will be described.
Reference numeral 310 denotes a microcomputer FPU (hereinafter referred to as a strobe microcomputer) that controls the operation of each part of the strobe device 300. Reference numeral 301 denotes a battery as a power source (VBAT) of the strobe, which is the same power source used for causing a discharge tube 307 and an LED 325 described later to emit light. Reference numeral 302 denotes a charging circuit that boosts the voltage of the battery 301 to several hundred volts, and accumulates energy for light emission in a main capacitor described later. This charging operation reduces the power supply voltage. Details will be described later with reference to FIG.

  Reference numeral 307 denotes a discharge tube, which emits light by receiving and exciting energy charged in a later-described main capacitor by receiving a pulse voltage of several KV applied from the trigger circuit 306, and irradiating the subject with the light. A light emission control circuit 308 controls the start of light emission of the discharge tube 307 together with the trigger circuit 306 and further controls the stop of light emission.

  Reference numeral 323 denotes a photodiode as a sensor that receives the light emission amount of the discharge tube 307, and receives light from the discharge tube 307 directly or through a glass fiber. Reference numeral 309 denotes an integration circuit that integrates the light reception current of the photodiode 323, and its output is input to the inverting input terminal of the comparator 312 and the A / D converter terminal of the flash microcomputer 310. The non-inverting input of the comparator 312 is connected to the D / A converter output terminal in the flash microcomputer 310, and the output of the comparator 312 is connected to the input terminal of the 311 AND gate. The other input of the AND gate 311 is connected to the light emission control terminal of the flash microcomputer 310, and the output of the AND gate 311 is input to the light emission control circuit 308.

  A zoom optical system 315 includes a reflector, 316 includes a panel and the like, and changes the irradiation angle of the strobe device 300. Here, by changing the distance between the reflector 315 and the zoom optical system 316 to a predetermined position, it is possible to change the irradiation guide number and light distribution to the subject.

  Reference numeral 313 denotes a zoom drive unit that moves a zoom optical system 316 including a motor and the like. The drive amount of the zoom optical system 316 is driven by receiving a signal from the zoom control terminal of the flash microcomputer 310. This zoom drive amount is calculated by the flash microcomputer 310 in accordance with the focal length information communicated from the lens microcomputer 201 via the camera microcomputer 101.

  Reference numeral 314 denotes a position detection unit such as an encoder for detecting the zoom position of the zoom optical system 316, which gives movement information to the position signal terminal of the stroboscopic microcomputer 310, and zooms by a necessary driving amount at the position signal terminal of the stroboscopic microcomputer 310. The motor in the drive unit 313 is driven.

  Reference numeral 320 denotes an input unit (input interface) for inputting various types of information. For example, a switch is installed on the side surface of the strobe device 300, and zoom information can also be input manually. Reference numeral 321 denotes a display unit that displays each state of the strobe device 300.

  A constant voltage circuit 322 outputs a constant voltage (for example, V1 output) from the battery 301. Reference numeral 324 denotes an LED control circuit that controls the light amount of a moving image shooting LED 325 that is an auxiliary light emitting unit described later, and causes the LED to emit light with a preset constant current of the LED, for example, based on a signal from the flash microcomputer 310.

  The LED 325 includes a light emitting element such as a white high-intensity LED, and is configured to irradiate according to an instruction from the LED control circuit 324. Reference numeral 350 denotes a light emitting unit for taking a still image of the flash device 300.

  Next, the LED control circuit 324 that controls the light amount of the LED 325 will be described with reference to FIG. An NPN transistor 1001 has a collector connected to the cathode of the LED 325, a base connected to a resistor 1002 described later, and an emitter connected to a resistor 1004 described later. Reference numeral 1003 denotes an operational amplifier. A non-inverting input is connected to a reference output (VREF (LED)) of a D / A converter in the stroboscopic microcomputer 310, and an inverting input is connected to one end of a resistor 1004 described later to detect a terminal voltage of the resistor 1004. The output of the operational amplifier 1003 is connected to the base of the NPN transistor 1001 through the resistor 1002. The resistor 1004 is connected to the emitter of the NPN transistor 1001 and the non-inverting input of the operational amplifier 1003, and the other end is a power supply (VBAT). The positive electrode of the power source (VBAT) 301 is connected to the anode of the LED 325.

  Next, LED lighting operation will be described. The reference output of the D / A converter in the stroboscopic microcomputer 310 is output as a voltage VREF (LED) set from 0V. The constant current iLED (LED) with respect to this VREF (LED) is represented by iLED (LED) = VREF (LED) / R0, and this constant current iLED (LED) is supplied to the LED 325. Here, R0 is the resistance value of the resistor 1004.

  The constant current iLED (LED) can be changed to various values by changing the level of the reference output voltage VREF (LED) of the D / A converter in the flash microcomputer 310 as described above.

  As described above, the flash microcomputer 310 changes the reference output voltage VREF (LED) according to the luminance information of the subject at the time of moving image shooting, thereby switching the constant current supplied to the LED 325 and changing the light emission amount of the LED 325. be able to.

  Next, the control circuit of the charging circuit 302 will be described with reference to FIG. The configuration of the forward charging circuit 302-1 will be described below. Reference numeral 401 denotes a resistor, one end of which is connected to the V1 output of the constant voltage circuit 322 and an emitter of a PNP transistor 403 described later, and the other end is connected to the base of the PNP transistor 403 and the resistor 402. A resistor 402 has one end connected to the base of the PNP transistor 403 and the resistor 401, and the other end connected to the CHG_ON terminal of the strobe microcomputer 310.

  A PNP transistor 403 has a resistor 401 and a resistor 402 connected to the base, a constant voltage circuit 322 and a resistor 401 connected to the emitter, and a resistor 404 connected to the collector, and functions as a charge start switch. Charging is started when the CHG_ON terminal of the flash microcomputer 310 becomes the Lo level.

  Reference numeral 404 denotes a resistor, one end of which is connected to the collector of the PNP transistor 403, and the other end is connected to a resistor 405 described later, an input IN 2 of an AND circuit 407 described later, and an input IN 2 of an AND circuit 408. A resistor 405 has one end connected to the resistor 404, the input IN 2 of the AND circuit 407 and the input IN 2 of the AND circuit 408, and the other end connected to the negative electrode of the battery 301.

  A logic circuit 406 is a NOT circuit, an input IN is connected to the CHG_CLK terminal of the flash microcomputer 310, and an output OUT is connected to an input IN1 of the AND circuit 407 by a logic circuit described later. The CHG_CLK terminal is a reference clock output terminal of a known separately-excited push-pull forward circuit, and a constant rectangular wave is output from the flash microcomputer 310. A logic circuit 407 is an AND circuit. The input IN1 is connected to the output OUT of the NOT circuit, and the input IN2 is connected to the resistor 404 and the resistor 405. The output OUT is connected to the resistor 412. Reference numeral 408 denotes an AND circuit which is an AND circuit. The input IN 1 is connected to the input IN of the NOT circuit and the CHG_CLK terminal of the strobe microcomputer 310. The input IN 2 is connected to the input IN 2 of the AND circuit 407, the resistor 404 and the resistor 405. The output OUT is connected to one end of the resistor 412.

  A resistor 409 has one end connected to the output OUT of the AND circuit 408 and the other end connected to the resistor 410 and the gate of the oscillation FET 411. 410 is a resistor, one end is connected to the resistor 409 and the gate of the oscillation FET 411, and the other end is connected to the negative electrode of the battery 301.

  Reference numeral 411 denotes an oscillation FET, which is a switch element for performing a charging operation, and is composed of an N-channel FET. This is one of the two push-pull type oscillation FETs. The gate is connected to the resistors 409 and 410, and the source is connected to the negative electrode of the battery 301. The drain is connected to a primary winding 415a of an oscillation transformer 415 described later.

  Reference numeral 412 denotes a resistor, one end of which is connected to the output OUT of the AND circuit 407, and the other end is connected to the resistor 413 and the gate of the oscillation FET 414. Reference numeral 413 denotes a resistor, one end is connected to the resistor 412 and the gate of the oscillation FET 414, and the other end is connected to the negative electrode of the battery 301.

  Reference numeral 414 denotes a switching element for performing a charging operation with an oscillation FET, which is composed of an N-channel FET. This is one of the two push-pull type oscillation FETs. The gate is connected to the resistors 412 and 413, and the source is connected to the negative electrode of the battery 301. The drain is connected to a primary winding 415c of an oscillation transformer 415 described later.

  Reference numeral 415 denotes an oscillation transformer, and the primary winding is divided between 415a and 415d at 415b and 415c. The secondary winding is configured between 415e and 415f. Reference numeral 416 denotes a bridge diode composed of 416j, 416g, 416h, and 416i.

  Reference numeral 417 denotes a main capacitor which stores energy for light emission. Reference numeral 418 denotes a resistor, and one end is connected to the positive electrode of the main capacitor 417. The other end is connected to a later-described resistor 419 and an MC_V terminal of an A / D conversion terminal of the stroboscopic microcomputer 310. Reference numeral 419 denotes a resistor, one end of which is connected to the resistor 418 and the MC_V terminal of the A / D conversion terminal of the strobe microcomputer 310, and the other end is connected to the negative electrode of the main capacitor 417.

  Thus, the voltage charged in the main capacitor 417 is divided by the resistors 418 and 419 functioning as a voltage detection circuit, and the divided voltage is input to the A / D conversion terminal of the flash microcomputer 310. The divided voltage is proportional to the voltage of the main capacitor, and charging is stopped when the main capacitor detects a voltage level necessary for light emission.

  The charging circuit 302-1 includes the elements 401 to 419 described above. The charging operation of the charging circuit 302-1 draws the current of the battery 301, and the power supply voltage rapidly decreases.

  Next, the configuration of the trigger circuit 306 will be described. The trigger circuit 306 includes the following elements 501 to 503. Reference numeral 501 denotes a resistor, and one end is connected to the positive electrode of the main capacitor 417, and the other end is connected to a trigger capacitor 502 described later and a drain of an IGBT 603 described later. The resistor 501 is a resistor for causing a current to flow through the trigger capacitor.

  Reference numeral 502 denotes a trigger capacitor, one end of which is connected to the resistor 501 and the drain of the IGBT 603, and the other end is connected to a primary winding of a trigger transformer 503 described later. The trigger capacitor 502 generates a pulse for light emission in the primary winding of the trigger transformer 503.

  Reference numeral 503 denotes a trigger transformer. One end of the primary side winding is connected to the trigger capacitor 502, and one end of the secondary side winding is connected to a trigger of a discharge tube described later. The other ends of the primary side winding and the secondary side winding are connected to the negative electrode of the main capacitor 417.

  Reference numeral 307 denotes a discharge tube, which emits light by receiving and exciting the energy charged in the main capacitor 417 by receiving and exciting a pulse voltage of several KV applied from the trigger circuit 306, and irradiates the subject with the light. The anode of the discharge tube 307 is connected to the positive electrode of the main capacitor 417, and the cathode is connected to the collector of an IGBT 606 described later. A light emission control circuit 308 controls the start of light emission of the discharge tube 307 together with the trigger circuit 306 and further controls the stop of light emission.

  The light emission control circuit 308 includes the following elements 601 to 606. Reference numeral 601 denotes a resistor, one end of which is connected to the TRG terminal of the flash microcomputer 310 and the other end is connected to the gate of the IGBT 603. Reference numeral 602 denotes a resistor, one end of which is connected to the negative electrode of the main capacitor 417 and the other end is connected to the gate of the rear IGBT 603.

  Reference numeral 603 denotes a light emitting IGBT, the gate is connected to the resistors 601 and 602, the drain is connected to the resistor 501, and the source is connected to the negative electrode of the main capacitor 417.

  Reference numeral 604 denotes a resistor, and one end is connected to the STP terminal of the flash microcomputer 310 and the other end is connected to the gate of the rear IGBT 606. Reference numeral 605 denotes a resistor, one end of which is connected to the negative electrode of the main capacitor 417 and the other end is connected to the gate of the IGBT 606.

  Reference numeral 606 denotes an IGBT for stopping light emission, the gate is connected to the resistors 604 and 605, the drain is connected to the cathode of the discharge tube 307, and the source is connected to the negative electrode of the main capacitor 417.

  A charging current limiting circuit 2000 is connected to the battery 301 and the charging circuit 302-1. The charging current limiting circuit 2000 includes the following elements 2001 to 2003.

  Reference numeral 2001 denotes a resistor, one end of which is connected to the positive electrode of the battery 301 and the other end is connected to a positive input of a comparator 2003 described later. Reference numeral 2002 denotes a resistor, one end of which is connected to a positive input of a comparator 2003 described later, and the other end is connected to a negative electrode of the battery 301. A comparator 2003 has a positive input connected to a voltage dividing point of the resistors 2001 and 2002, and a negative input connected to the VREF (PWR) terminal of the D / A conversion terminal of the strobe microcomputer 310. The output is connected to the input IN2 of the AND circuit 407 of the charging circuit 302-1 and the input IN2 of the AND circuit 408.

  Next, still image shooting accompanied by light emission of the discharge tube 307, subsequent charging operation, and auxiliary light operation during moving image shooting will be described with reference to FIG. FIG. 2A shows a shooting state determination signal controlled by the camera microcomputer 101 of the camera body 100 and shows moving image shooting at the Lo level and still image shooting at the Hi level. FIG. 2B shows the current of the battery 301 of the strobe device 300 consumed by the LED control circuit 324 and the LED 325 as auxiliary light emitting means. FIG. 2B shows an example in which 300 mA is consumed when the LED 325 is turned on. FIG. 2C shows the battery voltage of the battery 301 of the strobe device 300. When the LED 325 is turned on, the battery voltage decreases, and in the example, it decreases to a (V). FIG. 2D shows the release timing of still image shooting by the camera body 100. FIG. 2E shows the timing of main light emission (strobe light emission) of the discharge tube 307 by the strobe device 300. FIG. 2 (f) shows the timing of a charging signal for charging the main capacitor 417 after the flash tube 307 performs main light emission by the strobe device 300. FIG. 2G shows the current of the battery 301 consumed by charging the main capacitor 417 by the strobe device 300.

  When the still image shooting is performed at the timing shown in FIG. 2A, the still image shooting is released as shown in FIG. 2D, and the main light emission of the discharge tube 307 is performed as shown in FIG. Then, the main capacitor 417 is charged as shown in FIG. At this time, the charging current of the main capacitor 417 rises sharply at the start of charging as shown in FIG.

  When resuming moving image shooting in which the LED 325 is turned on after still image shooting, the charging operation of the main capacitor 417 is superimposed while the LED 325 is turned on. By superimposing the strobe charging operation, the LED current supplied to the LED control circuit 324 and the LED 325 becomes unstable as shown in FIG. 2B, and the light emission of the LED 325 fluctuates.

  For this reason, in this embodiment, the LED current is stabilized by limiting the charging current at the time of charging rise by the charging circuit 302 of the strobe device 300 as shown in FIG.

  Next, a specific operation of the camera microcomputer 101 during still image shooting will be described with reference to the flowcharts of FIGS.

  When a power switch (not shown) is turned on and the camera microcomputer 101 of the camera body 100 becomes operable, the camera microcomputer 101 starts a predetermined operation from step S1 in FIG.

  In step S1, the memory and port of the camera microcomputer 101 itself are initialized. Also, various switch states and preset input information input from the input unit 112 are read, and various shooting modes are set such as how to determine the shutter speed and how to determine the aperture.

  In step S2, it is determined whether or not SW1, which is a half-pressed state of a shutter button (not shown), is ON. If OFF, step S2 is repeated, and if ON, the process proceeds to step S3.

  In step S3, communication is performed with the lens microcomputer 201 in the lens unit 200 via the communication line SC. Then, lens information such as focal length information (hereinafter referred to as lens focal length information) of the lens unit 200, optical information necessary for distance measurement and photometry is acquired.

  In step S4, it is determined whether or not the strobe device 300 is attached to the camera body 100. If the strobe device 300 is attached to the camera body 100, the process proceeds to step S5, and if not, the process proceeds to step S6.

  In step S5, the camera microcomputer 101 communicates with the flash microcomputer 310 via the communication line SC, and outputs the focal length information of the lens acquired in step S3 to the flash microcomputer 310. Accordingly, the flash microcomputer 310 drives the zoom drive unit 313 based on the received focal length information of the lens, detects the position by the encoder 314, and controls the flash irradiation angle.

  In step S6, of the camera shooting modes set in step S1, is the mode in which the camera performs an autofocus detection operation (AF mode) or the mode in which no autofocus detection operation is performed (MF mode)? Determine. If it is AF mode in step S6, it will progress to step S7, and if it is MF mode, it will progress to step S9.

  In step S7, the focus detection circuit 107 is driven to perform a focus detection operation by a known phase difference detection method. Also, in step S7, which distance measurement point is to be focused from a plurality of distance measurement points is determined in accordance with the point input and set by the input unit 112 or the shooting mode of the camera.

  In step S8, the distance measuring point determined in step S7 is stored in a RAM (random access memory) (not shown) in the camera microcomputer 101. In step S8, the camera microcomputer 101 calculates the driving amount of the lens group 202 based on information from the focus detection circuit 107. The camera microcomputer 101 communicates with the lens microcomputer 201 in the lens unit 200 via the communication line SC. Based on the calculation result, the lens microcomputer 201 controls the lens driving circuit 203 to drive the lens group 202 to the in-focus position. Proceed to step S9.

  In step S9, the photographing screen is divided into six photometric areas, and the subject luminance value is obtained by the photometric circuit 106 for each photometric area. The luminance value is stored in the RAM as EVb (i) (i = 0 to 5).

  In step S <b> 10, gain setting processing based on the gain setting information input from the input unit 112 is performed by the gain switching circuit 108. The gain setting input from the input unit 112 is, for example, ISO sensitivity setting. In step S <b> 10, the camera microcomputer 101 communicates with the strobe microcomputer 310 via the communication line SC, and outputs gain setting information to the strobe microcomputer 310.

  In step S11, it is determined whether or not it is necessary to cause the discharge tube 307 to emit light at the time of still image shooting from the subject brightness values EVb of a plurality of photometry areas, which are the photometry results in step S9. Then, the shutter speed (Tv) and aperture value (Av) suitable for still image photography (light emission photography) with light emission of the discharge tube 307, or suitable for still image photography (non-light emission photography) that does not cause the discharge tube 307 to emit light. The shutter speed (Tv) and aperture value (Av) are determined.

  In step S12, a subroutine for moving image shooting processing including determination of whether or not to perform moving image shooting is performed, and the process proceeds to step S13. A description of the subroutine for the moving image shooting process will be given later with reference to FIG.

  In step S13, it is determined whether or not SW2, which is a shooting start switch (not shown), is ON. If it is OFF, the process returns to step S2, and if it is ON, the process proceeds to step S14 in the flowchart shown in FIG. Perform the release operation. The release operation will be described with reference to the flowchart of FIG.

  In step S14, it is determined whether or not still image shooting is performed by causing the discharge tube 307 of the strobe device 300 to emit light. If the discharge tube 307 is caused to emit light, the process proceeds to step S15, and if not, the process proceeds to step S29.

  In step S15, it is determined whether or not a charging completion signal indicating that the charging voltage of the main capacitor 417 has reached the voltage level necessary for the light emission of the discharge tube 307 is obtained from the flash microcomputer 310 via the communication line SC. judge. If the charging completion signal has been acquired, the process proceeds to step S15. If the charging completion signal has not been acquired, flash photography cannot be performed, and the process proceeds to step S29.

  In step S <b> 16, the subject brightness is acquired by the metering circuit 106 in order to measure the ambient light brightness immediately before the pre-flash of the strobe device 300. Each luminance value of the photometric area divided into six is stored in a RAM (not shown) as EVa (i) (i = 0 to 5).

  In step S17, the camera microcomputer 101 outputs a pre-fire start signal to the flash microcomputer 310 via the SC line. The stroboscopic microcomputer 310 controls the light emission control circuit 308 and the trigger circuit 306 according to the pre-light emission start signal, and performs a pre-light emission operation for emitting light and irradiating the subject.

  In step S <b> 18, the camera microcomputer 101 acquires the subject luminance at the time of pre-emission by the photometric circuit 106. Each luminance value of the six photometry areas is stored in the RAM as EVf (i) (i = 0 to 5).

  In step S19, the camera microcomputer 101 raises the main mirror 104 prior to the exposure operation and moves it away from the photographing optical path. It should be noted that this step may be omitted if the video has been shot until just before and the main mirror is up.

In step S20, the difference between the subject luminance value EVf at the time of pre-light emission acquired in step S18 and the subject luminance value (external light luminance) EVa immediately before the pre-light emission acquired in step S16 is calculated as in the following equation 1, and pre-light emission is performed. The luminance value EVdf (i) of only the reflected light component is extracted. Extraction of the reflected light component of pre-emission is performed for every six photometric areas.
EVdf (i) ← LN2 (2 ^ EVf (i) -2 ^ EVa (i)) (i = 0 to 5) (Formula 1)

  In step S <b> 21, guide number (Qpre) data representing the light emission amount at the time of pre-flash is acquired from the flash device 300. Here, the guide number (Qpre) of the pre-light emission changes depending on the charging voltage and the zoom position of the main capacitor 417 immediately before the pre-light emission. For this reason, the camera microcomputer 101 acquires a value obtained by correcting the strobe microcomputer 310 from the guide number corresponding to the zoom position, the charging voltage of the main capacitor 417, and the like.

  In step S22, the discharge tube 307 is caused to emit main light from the distance measuring point (Focus.p), focal length (f), pre-flash guide number (Qpre), bounce flag (F_Bounce), etc. Select the appropriate exposure. The selected photometric area is stored in the RAM as P (any one of 0 to 5).

Then, the main light emission amount is calculated as shown in Equation 2 below. From the exposure value (EVs), the subject brightness (EVb), the sensitivity (gain), and the brightness value EVdf (p) of the pre-emission reflected light only, the subject in the selected photometry area (P) is compared with the pre-emission amount. The appropriate relative ratio (r) of the main light emission amount is obtained.
r ← LN2 (2 ^ EVs-2 ^ EVb (p))-EVdf (p) (Formula 2)

Here, the difference between the exposure value (EVs) and the subject luminance (EVb) expanded is taken so that the exposure when stroboscopic light is applied is appropriate by adding the stroboscopic light to the external light. It is for control. Furthermore, the relative ratio (r) is calculated using the shutter speed (TV), the pre-emission emission time (t_pre), and the correction coefficient (c) preset by the photographer through the input unit 112 as shown in Equation 3 below. ) And a new relative ratio r is calculated.
r ← r + TV−t_pre + c (Formula 3)

  Here, the correction using the shutter speed (TV) and the pre-flash emission time (t_pre) is performed in the strobe circuit with the pre-flash photometric integration value (INTp) and the main flash photometry integration value (INTm). This is to compare correctly.

  In step S <b> 23, the camera microcomputer 101 transmits a relative value (r) with respect to the pre-flash quantity to the flash device 300 as the main flash quantity information, which is information indicating the main flash quantity, to the flash microcomputer 310 via the SC line.

  In step S24, an instruction is given to the lens microcomputer 201 so that the set aperture value (AV) is obtained, and an instruction to start running the shutter 103 is given via the shutter control circuit. Note that when the moving image shooting is performed until immediately before and the shutter 103 is already open, the open state is maintained.

  In step S25, the camera microcomputer 101 gives a main light emission start signal to the flash microcomputer 310 via the SC line in synchronization with the main exposure. Then, the flash microcomputer 310 performs the main light emission control of the discharge tube 307 based on the relative value (r) sent from the camera so as to obtain an appropriate light emission amount.

  In the process of step S30 that proceeds when the flash photography is not performed or when the charge completion signal is not acquired, the same process as that of step S24 is performed. In step S31, the main exposure is performed without causing the flash device 300 to emit light.

  When the series of exposure operations is completed in this way, in step S26, it is determined whether or not the moving image shooting is interrupted in order to perform still image shooting. If movie shooting has been interrupted, the process proceeds to step S27, and if movie shooting has not been interrupted, the process proceeds to step S32.

  In step S <b> 27, a signal obtained by amplifying the output from the image sensor 102 with the gain set by the gain switching circuit 108 is converted as a digital signal by the A / D converter 109. The signal processing circuit 111 performs predetermined development processing such as white balance on the pixel data converted into the digital signal. In step S27, the development process is performed with the main mirror 104 up to reduce the interruption time as much as possible and resume moving image shooting.

  In step S28, the developed image data is stored in a memory (not shown), and moving image shooting is resumed in step S29.

  If the moving image shooting is not interrupted for still image shooting, the main mirror 104 that has been moved away from the shooting optical path is lowered and inclined in the shooting optical path again in step S32.

  Thereafter, in steps S33 and S34, processing similar to that in steps S27 and S28 is performed, and the series of release operations is completed.

  Next, a subroutine for the moving image shooting process in step S12 in the flowchart shown in FIG. 10 will be described with reference to FIG.

  In step S201, it is determined whether or not the moving image shooting button for starting moving image shooting in the input unit 112 of the camera body 100 is pressed to enter the moving image shooting mode. If it is the moving image shooting mode, the fact that it is the moving image shooting mode is stored in the RAM in the camera microcomputer 101, and the process proceeds to step S202. If not, the process proceeds to step S13 in FIG. When the moving image shooting button described above is pressed to enter the moving image shooting mode, the main mirror 104 is raised and the shutter 103 is opened to start moving image shooting.

  In step S202, based on the photometric result acquired in step S9 of FIG. 10, it is determined whether or not the LED 325 is lit as auxiliary light during moving image shooting. When the LED 325 is turned on, the process proceeds to step S203, and when the LED 325 is not turned on, the process proceeds to step S204.

  In S203, lighting control of the LED 325 is performed. At this time, the light emission amount of the LED 325 may be a predetermined light emission amount determined in advance, or may be a light emission amount set based on the photometry result acquired in step S9. If it is in the lighting state, the process directly proceeds to step S205.

  In step S204, if the LED 325 is lit, it is turned off. Here, the reference output voltage VREF (LED) of the D / A converter in the stroboscopic microcomputer 310 corresponding to the required amount of light is set to 0V. If the light is off, the process proceeds directly to step S205.

  In step S205, it is determined whether or not SW2, which is a shooting start switch (not shown) for still image shooting, is turned on. If it is turned on, the process proceeds to step S206, and moving image shooting is interrupted. If it is OFF, the process proceeds to step S214. Continue video recording. At this time, in the present embodiment, a case where the up state is maintained without lowering the main mirror 104 that is up will be described, but the main mirror 104 may be down. Further, although a case will be described in which a transition is made to still image shooting without closing the shutter 103 in the open state, still image shooting may be performed after the shutter 103 is once in a light-shielded state.

  In step S206, the moving image shooting interruption information indicating that the moving image shooting is interrupted by turning on SW2 during moving image shooting is stored in the RAM in the camera microcomputer 101.

  In step S207, it is determined whether or not the LED 325 has been turned on as auxiliary light during moving image shooting. If the LED 325 has been turned on, the process proceeds to step S208. If the light has been turned off, the process proceeds to step S209.

  In step S208, LED_ON information indicating that the LED 325 is in a lighting state is stored in the RAM in the camera microcomputer 101, and the process proceeds to step S210. In step S208, LED_OFF information indicating that the LED is turned off is stored in the RAM in the camera microcomputer 101, and the process proceeds to step S210.

  In step S210, it is determined whether or not still image shooting is performed by causing the discharge tube 307 of the strobe device 300 to emit light. If the discharge tube 307 is caused to emit light, the process proceeds to step S211, and if not, the process proceeds to step S13 in FIG.

  In step S <b> 211, the camera microcomputer 101 communicates with the strobe microcomputer 310 via the communication line SC, and outputs LED_ON information, LED_OFF information, and the like, which are information indicating the state of the LED 325 before taking a still image, to the strobe microcomputer 310.

  In step S212, it is determined whether or not moving image shooting has ended. If completed, the process proceeds to step S213, and if not completed, the process proceeds to step S202. In step S213, moving image shooting completion processing is performed.

  Next, a specific operation (strobe control operation) in the strobe microcomputer 310 in the strobe device 300 will be described using the flowchart of FIG. 13 and the operation timing of the charging circuit of FIG.

  When a power switch (not shown) is turned on and the flash microcomputer 310 becomes operable, the flash microcomputer 310 starts a predetermined operation from step S101.

  In step S101, the memory and port of the flash microcomputer 310 itself are initialized. Also, the state of various switches input from the input unit 320 and preset input information are read to set the flash photography mode, the light emission amount, and the like. When the camera microcomputer 101 communicates with the flash microcomputer 310 via the communication line SC, information from the camera microcomputer 101 is acquired. The acquired information is stored in a RAM (not shown) in the flash microcomputer 310.

  In step S102, charging current determination is performed to change the strobe charging current according to whether or not the LED 325 is turned on during moving image shooting. The charging current determination is performed based on the LED_ON information or LED_OFF information stored in steps S208 and S209 in FIG. 12. If the LED_OFF information is stored, the process proceeds to step S103. If the LED_ON information is stored, the process proceeds to step S104. .

  In step S103, the lower limit of the battery voltage is set to Vth0 (V) = 0 as shown in [7] in FIG. 6 so as not to limit the charging current. By setting Vth0 (V) = 0, the charging current is not limited and a current flows up to a1 (A). That is, when the LED 325 is turned off during moving image shooting, an upper limit is not set for the charging current of the main capacitor 417.

  In step S104, the upper limit level of the charging current is set so that the upper limit of the charging current is a2 (A), and the lower limit of the battery voltage is set to Vth1 (V) as shown in [7] in FIG. Here, the upper limit of the charging current is set to a1 (A) by setting the VREF (PWR) terminal output to Vth0 (V), and the upper limit is set to a2 (A) by setting the VREF (PWR) terminal output to Vth1 (V). However, the upper limit of the charging current may be set more finely. Further, the upper limit current a2 (A) of the charging current is a current obtained by subtracting the consumption current (iLED (LED)) of the LED 325 from the maximum value of the charging current (here, a1 (A)).

  In step S105, the charging operation of the charging circuit 302 is started to prepare for light emission. In step S106, lens focal length information is acquired from the camera microcomputer 101 via the communication line SC. Then, the focal length information of the lens transmitted from the camera microcomputer 101 is stored (stored) in its own memory. If the focal length information of the lens has been stored in its own RAM before this, the stored content is updated. In step S107, the focal length information of the lens stored in its own RAM is displayed on the display unit 321.

  In step S108, the irradiation angle is calculated based on the focal length information of the lens acquired in step S106, and movement information is given to the position signal terminal of the flash microcomputer 310 via the encoder 314 so that the calculated irradiation angle is obtained. . Then, the motor in the zoom drive unit 313 is operated by a required drive amount at the position signal terminal of the flash microcomputer 310, and is moved to a predetermined position by the position signal of the encoder 314.

  In step S109, it is determined whether or not the charging voltage of the main capacitor 417 has reached the voltage level necessary for light emission of the discharge tube 307 (charging is completed), and has reached the voltage level necessary for light emission of the discharge tube 307. If it is determined that there is, the process proceeds to step S110. If it is determined in step S109 that the voltage level necessary for the light emission of the discharge tube 307 has not been reached, step S109 is repeated until the required voltage level is reached.

  Here, a detailed description of the charging operation will be given with reference to FIGS. As indicated by [2] CHG_ON in FIG. 6, before the charging operation is performed, the CHG_ON terminal of the stroboscopic microcomputer 310 is Hi level and the PNP transistor 403 is off. Therefore, the input IN2 of the AND circuit 407 and the input of the AND circuit 408 IN2 becomes Lo level. Since both the output OUT of the AND circuit 407 and the AND circuit 408 are at the Lo level, both the oscillation FET 411 and the oscillation FET 412 are turned off, so that the charging operation is not performed.

  When starting the charging operation, the CHG_ON terminal of the flash microcomputer 310 is lowered from the Hi level to the Lo level. When the CHG_ON terminal is lowered from the Hi level to the Lo level, the base of the PNP transistor 403 pulled up by the resistor 401 is pulled down to the Lo level via the resistor 402, and the PNP transistor 403 is turned on.

  The output voltage V1 of the constant voltage circuit 322 is input to the input IN2 of the AND circuit 407 and the input IN2 of the AND circuit 408 through the resistor 404, whereby the input IN2 of the AND circuit 407 and the input IN2 of the AND circuit 408 are changed. Become Hi level.

  Further, as indicated by [4] 408OUT in FIG. 6, Hi level and Lo level are alternately input to the input IN1 of the AND circuit 408 by the pulse from the CHG_CLK terminal of the flash microcomputer 310. The output OUT of the AND circuit 408 outputs a signal synchronized with the pulse from the CHG_CLK terminal.

  Similarly, as indicated by [5] 407OUT in FIG. 6, the pulse from the CHG_CLK terminal is inverted and output by the NOT circuit 406, and the inverted pulse is input to the input IN1 of the AND circuit 407. Therefore, the output OUT of the AND circuit 407 is a signal in which the Hi level and the Lo level are inverted from the output OUT of the AND circuit 408.

  When the output OUT of the AND circuit 408 becomes Hi level, the oscillation FET 411 is turned on via the resistor 409, and the drain and source of the oscillation FET 411 are connected from the positive electrode of the battery 301 to the primary windings 415b to 415a of the oscillation transformer 415. Flowing.

  Since an electric current flows from the primary windings 415b to 415a of the primary winding oscillation transformer 415, an induction current flows from the secondary windings 415e to 415f. The main capacitor 417 is charged by the loop of the positive and negative electrodes of the main capacitor 417, the bridge diode 416j and the secondary winding 415e via the bridge diode 416i.

  When the output OUT of the AND circuit 408 becomes Lo level, the oscillation FET 411 is turned off via the resistor 409, and the oscillation FET 411 is turned off from the positive electrode of the battery 301 via the primary windings 415b to 415a of the oscillation transformer 415. Charging 417 stops. Then, the operation of the AND circuit 407 is performed inversely to the operation of the AND circuit 408, and a push-pull operation is performed.

  When the output OUT of the AND circuit 407 becomes Hi level, the oscillation FET 414 is turned on via the resistor 412, and between the positive electrode of the battery 301 and the drain-source of the oscillation FET 414 via the primary windings 415 c to 415 d of the oscillation transformer 415. Flowing.

  Since an electric current flows from 415c to 415d of the primary winding of the primary winding oscillation transformer 415, an induced current flows from the secondary windings 415f to 415e. The main capacitor 417 is charged through the loop of the positive and negative electrodes of the main capacitor 417, the bridge diode 416h and the secondary winding 415f via the bridge diode 416g.

  When the output OUT of the AND circuit 407 becomes Lo level, the oscillation FET 414 is turned off via the resistor 411, and the oscillation FET 414 is turned off from the positive electrode of the battery 301 via the primary windings 415c to 415d of the oscillation transformer 415. Charging 417 stops.

  In this way, the main capacitor 417 is charged. At this time, if there is no current limitation on the charging current, the battery 301 is almost short-circuited by the oscillation FET 411 and the oscillation FET 414, so that a large current flows and the battery voltage decreases.

  Therefore, the upper limit value of the charging current is set to a2 (A) so that a current corresponding to the consumption current iLED (LED) of the LED control circuit 324 can be secured as shown in [6] battery current in FIG. Then, a voltage level corresponding to the upper limit value a2 (A) is calculated and set as Vth1 in the VREF (PWR) terminal of the D / A conversion terminal of the flash microcomputer 310.

Next, the current limiting operation of the charging current limiting circuit 2000 will be described.
The comparator 2003 compares the voltage obtained by dividing the voltage of the battery 301 with the voltage (Vth1) set at the VREF (PWR) terminal of the D / A conversion terminal of the strobe microcomputer 310. When the voltage obtained by dividing the voltage of the battery 301 is equal to or lower than the set voltage (Vth1), the output of the comparator 2003 is lowered to Lo, and when it exceeds the set voltage (Vth1), Lo is released. In this way, while the voltage of the battery 301 is decreasing, the input IN2 of the AND circuit 407 and the input IN2 of the AND circuit 408 of the charging circuit 302-1 become Lo, so that the outputs OUT of the AND circuit 407 and the AND circuit 408 are output. Becomes Lo output.

  Therefore, even if the oscillation FET 411 and the oscillation FET 414 are in the on state, the oscillation is forcibly stopped, so that the charging current is reduced and the charging current can be prevented from exceeding the upper limit value. Returning to the flowchart of FIG. In step S110, the camera microcomputer 101 is informed via the communication line SC that a charging completion signal is output to prepare for light emission.

  Then, in the next step S111, it is determined whether or not the light emission start signal is output from the camera microcomputer 101. If the light emission start signal is not output, the process returns to S102 and the above steps are repeated. On the other hand, if the light emission start signal is output, it will progress to step S112.

  In S112, a trigger signal is given from the light emission control terminal of the flash microcomputer 310 to the light emission control circuit 308 via the AND gate 311 to start light emission of the discharge tube 307.

Here, a detailed description of the light emitting operation will be given with reference to FIGS.
When the main capacitor 417 is charged by the charging circuit 302-1, electric charge is accumulated in the trigger capacitor 502 via the resistor 501. At the time of light emission, a rectangular wave trigger signal is output from the TRG terminal of the flash microcomputer 310.

  As a result, the light emitting IGBT 603 is turned on via the resistor 601. Further, the Hi level is output from the STP terminal of the flash microcomputer 310. As a result, the light emission stopping IGBT 606 is turned on via the resistor 604. As described above, both ends of the discharge tube 307 and both ends of the main capacitor 417 are connected.

  When the light emitting IGBT 603 is turned on, the trigger capacitor 502 is discharged and a pulse signal is generated on the primary side of the trigger transformer 503. Then, a high voltage of several kV is generated on the secondary side of the trigger transformer 503, the discharge tube 307 is triggered, and the charge accumulated in the main capacitor 417 is discharged to emit light.

  Returning to the flowchart of FIG. In step S113, it is determined whether or not the light emission amount of the discharge tube 307 has reached the light emission amount corresponding to the light amount determined by the actual light emission amount calculation value from the camera microcomputer 101 to the flash microcomputer 310 via the communication line SC. Alternatively, it is determined whether or not a light emission amount corresponding to a predetermined pre-light emission amount has been reached.

  If it is determined in step S113 that the light has not been reached, the light emission is continued. If it is determined that the light has reached, the process proceeds to step S114. At this time, the light level used for determination is changed according to whether the light emission start signal output from the camera microcomputer 101 is the pre-light emission start signal or the main light emission start signal.

In step S <b> 114, a light emission stop signal is output from the AND gate 311, and the light emission control circuit 308 stops the light emission of the discharge tube 307. In the light emission stop operation in FIG. 4, the Lo level is output from the STP terminal of the flash microcomputer 310 when the appropriate light amount is reached, and the light emission stop IGBT 606 is turned off via the resistor 604. Thereby, the light emission of the discharge tube 307 stops.
Thereafter, the process returns to step S102, and the above steps are repeated.

  Note that the charging current may be increased as the amount of auxiliary light required during moving image shooting is small and the auxiliary light consumption current (iLED (LED)) is small. For example, in the charging current determination process in step S102, the DREF converter 310 of the strobe microcomputer 310 can set the VREF (PWR) terminal output to Vth2 (V), which is larger than Vth1 (V), thereby increasing the upper limit of the charging current. It can be less than a2 (A). Thus, the upper limit value of the charging current may be switched more finely according to the amount of auxiliary light required.

  As described above, even when the main capacitor 417 is charged when the LED is turned on as auxiliary light for moving image shooting, the auxiliary light consumption current (iLED (LED )) Can be secured. Therefore, even during the charging operation, the luminance of the LED 325 does not vary, and a good moving image with no unevenness in brightness can be obtained.

  The operation of the charging circuit 302 according to the second embodiment of the present invention will be described below with reference to FIGS. In the second embodiment, the configuration of the charging circuit is different from that of the first embodiment, and the charging method of the charging circuit 302-1 in FIG. 4 is changed from the forward method to the flyback method of the charging circuit 302-2. Also, the current limiting method differs from the first embodiment in the charging operation in steps S103 and S104 in FIG.

  With reference to FIG. 8, the still image shooting accompanied by the issuance of the discharge tube 307 in the second embodiment, the subsequent charging operation, and the auxiliary light operation during moving image shooting will be described. 8A to 8G correspond to FIGS. 2A to 2G, respectively, and detailed description thereof will be omitted.

  In this embodiment, as shown in FIG. 8G-2, the charging current 302-2 of the strobe device 300, which will be described later, is used to limit the charging current at the start of charging, thereby stabilizing the LED current.

  FIG. 5 shows an example in which the charging method of the charging circuit 302-1 of FIG. 4 described in the first embodiment is changed from the forward method to the flyback method of the charging circuit 302-2. The charging current can be limited as shown in 8 (g-2).

The structure of the flyback charging circuit 302-2 will be described below.
Reference numeral 701 denotes a power supply capacitor, one end of which is connected to the positive electrode of the battery 301 and the other end is connected to the negative electrode (GND) of the battery 301. A charging current detection circuit 702 detects a charging current (primary current of an oscillation transformer 705 described later) of the battery 301 and is connected to a P_IN terminal of an A / D converter terminal of the flash microcomputer 310 and an oscillation transformer 705 described later. Note that the charging current may be determined by detecting the voltage using a resistor instead of detecting the current by the charging current detection circuit.

  Reference numeral 704 denotes an oscillation FET which is a primary side switching element of the charging circuit 302-2, and the charging current of the battery 301 is controlled by the switching operation of the oscillation FET 704. The gate of the oscillation FET 704 is connected to the CHG_CLK terminal and the resistor 703 of the strobe microcomputer 310, the source is connected to the resistor 703 and the negative electrode of the battery 301, and the drain is connected to the b terminal on the primary side of the oscillation transformer 705. Has been.

  A resistor 703 is connected between the gate and source of the oscillation FET 704, one end is connected to the negative electrode of the battery 301, and the other end is connected to the gate of the oscillation FET 704 and the CHG_CLK terminal of the strobe microcomputer 310.

  Reference numeral 705 denotes an oscillation transformer that boosts the voltage of the battery 301 and supplies electric charge to the main capacitor 417. The 705a terminal of the oscillation transformer 705 is connected to the charging current detection circuit 702, and the 705b terminal is connected to the drain of the oscillation FET 704. A 705c terminal of the oscillation transformer 705 is connected to a cathode of a diode 707 described later, and a 705d terminal is connected to an anode of a diode 706 described later.

  Reference numeral 706 denotes a diode, which is a rectifier diode. The anode is connected to the 705d terminal of the oscillation transformer 705 and the cathode is connected to the positive electrode of the main capacitor 417. Reference numeral 707 denotes a diode, the cathode of which is connected to the 705c terminal of the oscillation transformer 705, and the anode of which is connected to a resistor 708 and an emitter of an NPN transistor 709 described later.

  Reference numeral 708 denotes a resistor, one end of which is connected to the anode of the diode 707 and the other end is connected to the negative electrode of the battery 301. Reference numeral 709 denotes an NPN transistor for detecting a secondary current of the oscillation transformer 705. The emitter is connected to the anode of the diode 707 and the resistor 708. The base is connected to the resistor 708 and the negative electrode of the battery 301. The collector is connected to the resistor 710 and the resistor 711. It is connected to the. Reference numeral 710 denotes a resistor, one end of which is connected to the output V1 of the constant voltage circuit 322, and the other end is connected to a resistor 711 described later. A resistor 711 has one end connected to the resistor 710 and the other end connected to the S_IN terminal of the flash microcomputer 310.

  The S_IN terminal of the strobe microcomputer 310 is an input terminal, and detects that the voltage has dropped from the Hi level of the output signal level of the constant voltage circuit 322 to the Lo level when the NPN transistor 709 is turned on.

  The operation of the charging circuit 302-2 at this time will be described with reference to FIGS. Here, FIG. 7A shows a drive sequence when the drive pulse width is X1. This pulse width is a time set to minimize the charging time.

  As indicated by [1] CHG_CLK in FIG. 7A, a pulse signal having a pulse width X1 is output from the CHG_CLK terminal of the flash microcomputer 310 to the gate of the oscillation FET 704. As a result, the oscillation FET 704 is turned on, and current flows from the positive electrode of the battery 301 via the charging current detection circuit 702 via the a terminal-b terminal of the oscillation transformer 705 and the drain-source of the oscillation FET 704.

  At this time, the current flowing on the primary side of the oscillation transformer 705 (hereinafter referred to as primary current) is determined by the pulse width X1 and the power supply voltage of the battery 301, as shown in FIG. 7 (a) [2] primary current. The primary current flows a1 (A) at the maximum. The current value at this time is set to a value at which the oscillation transformer 705 is not magnetically saturated.

  When the pulse signal from the CHG_CLK terminal becomes Lo level and the oscillation FET 704 is turned off, the energy stored in the oscillation transformer 705 is released when the oscillation FET 704 is turned on, so that a current flows from the c terminal to the d terminal of the oscillation transformer 705. The current at this time becomes a current loop of the d terminal of the oscillation transformer 705-the anode-cathode of the diode 706, the positive and negative electrodes of the main capacitor 417, the resistor 708, the anode-cathode of the diode 707, and the c terminal of the oscillation transformer 705.

  The current flowing on the secondary side of the oscillation transformer 705 (hereinafter referred to as the secondary current) is such that the pulse signal from the CHG_CLK terminal becomes Lo level as shown in [3] Secondary current in FIG. 7A. Immediately after that, it becomes the maximum b1 (mA) and gradually decreases from there.

  When a secondary current is generated, a current flows through the resistor 708 to generate a voltage, and the NPN transistor 709 is turned on. For this reason, since the current flows from the output of the constant voltage circuit 322 to the collector-emitter of the NPN transistor 709 via the resistor 710, the S_IN terminal of the strobe microcomputer 310 becomes Lo level.

  When the energy of the oscillation transformer 705 is released and the secondary current decreases, no current flows through the resistor 708 and the NPN transistor 709 is turned off. For this reason, the S_IN terminal of the strobe microcomputer 310 becomes Hi level. When the S_IN terminal of the strobe microcomputer 310 changes from the Lo level to the Hi level, the next drive pulse is output.

  When resuming moving image shooting with the LED 325 lit after still image shooting, the strobe charging operation is superimposed while the LED 325 is lit. By superimposing the strobe charging operation, the LED current supplied to the LED control circuit 324 and the LED 325 becomes unstable, and the light emission of the LED 325 fluctuates. Therefore, in order to prevent fluctuations in the light emission of the LED 325, charging is performed in a manner that is superimposed on the lighting of the LED 325 as follows, and charging is performed more than in the case of performing the strobe charging without being superimposed on the lighting of the LED 325. Reduce the current.

FIG. 7B shows a drive sequence when the drive pulse width is X2.
This pulse width is a time set to limit the upper limit of the primary current of the battery 301 so that the auxiliary light consumption current (iLED (LED)) can be secured. Here, the upper limit value of the charging current is changed to a2 (A) lower than a1 (A).

  As shown in [1] CHG_CLK in FIG. 7B, a pulse signal having a pulse width X2 is output from the CHG_CLK terminal of the flash microcomputer 310 to the gate of the oscillation FET 704. As a result, the oscillation FET 704 is turned on, and current flows from the positive electrode of the battery 301 via the charging current detection circuit 702 via the a terminal-b terminal of the oscillation transformer 705 and the drain-source of the oscillation FET 704.

  At this time, the primary current of the oscillation transformer 705 is determined by the pulse width X2 and the power supply voltage of the battery 301. As shown in FIG. 7B [2] primary current, the primary current flows through a2A (ampere) at the maximum. The current value at this time is set to a value at which the oscillation transformer 705 is not magnetically saturated.

  When the pulse signal from the CHG_CLK terminal becomes Lo level and the oscillation FET 704 is turned off, the energy stored in the oscillation transformer 705 is released when the oscillation FET 704 is turned on, so that a current flows from the c terminal to the d terminal of the oscillation transformer 705.

  The current at this time becomes a current loop of the d terminal of the oscillation transformer 705-the anode-cathode of the diode 706, the positive and negative electrodes of the main capacitor 417, the resistor 708, the anode-cathode of the diode 707, and the c terminal of the oscillation transformer 705.

  The secondary current of the oscillation transformer 705 becomes the maximum b2 (mA) immediately after the pulse signal from the CHG_CLK terminal becomes Lo level, as indicated by [3] secondary current in FIG. Go down.

  When a secondary current is generated, a current flows through the resistor 708 to generate a voltage, and the NPN transistor 709 is turned on. For this reason, since the current flows from the output of the constant voltage circuit 322 to the collector-emitter of the NPN transistor 709 via the resistor 710, the S_IN terminal of the strobe microcomputer 310 becomes Lo level.

  When the energy of the oscillation transformer 705 is released and the secondary current decreases, no current flows through the resistor 708 and the NPN transistor 709 is turned off. For this reason, the S_IN terminal of the strobe microcomputer 310 becomes Hi level. When the S_IN terminal of the strobe microcomputer 310 changes from the Lo level to the Hi level, the next drive pulse is output.

  As described above, the drive pulse width of the CHG_CLK terminal output of the flash microcomputer 310 is set to X1 when the process proceeds to step S103 in FIG. 13, and is set to X2 when the process proceeds to step S104. The upper limit is switched.

  In this embodiment, the drive pulse width of the CHG_CLK terminal output of the flash microcomputer 310 is switched between X1 and X2, but the drive pulse width may be switched more finely according to the required amount of auxiliary light. For example, the drive pulse width is increased in a range not exceeding X1, so that the strobe charging current increases as the auxiliary light consumption current (iLED (LED)) decreases as the amount of auxiliary light required during movie shooting decreases. Also good.

  As described above, even when the charging operation of the main capacitor 417 is performed when the LED 325 is turned on as auxiliary light for moving image shooting, the auxiliary light consumption current (iLED (LED )) Can be secured. Therefore, even during the charging operation, the luminance of the LED 325 does not vary, and a good moving image with no unevenness in brightness can be obtained.

  Hereinafter, with reference to FIG. 9, a still image shooting accompanied by light emission of the discharge tube 307 in the third embodiment of the present invention, a subsequent charging operation, and an auxiliary light operation during moving image shooting will be described. 9A to 9G correspond to FIGS. 2A to 2G, respectively, but the timing for resuming moving image shooting and the timing for relighting the LED 325 are different. That is, the present embodiment is different from the first embodiment in that the charging operation is started after the still image is shot and the LED 325 is restarted after the charging current in the charging operation becomes a predetermined value or less.

  The charging current rises sharply as shown in FIG. 9G after the start of the charging operation. Therefore, when resuming moving image shooting in which the LED 325 is turned on after still image shooting, the charging current is a current (a2 () obtained by subtracting the auxiliary light consumption current (iLED (LED)) from the strobe charging maximum current (a1 (A)). A)) Wait until the following is reached, and then resume the video shooting.

  The timing for resuming moving image shooting will be described with reference to an operation flowchart of the flash microcomputer 310 shown in FIG. The steps after step S308 are the same as the steps after step S109 in FIG.

  In step S301, the memory and port of the flash microcomputer 310 itself are initialized, and then the charging operation of the charging circuit 302 is started in step S302.

  In step S303, the focal length information of the lens acquired from the camera microcomputer 101 via the communication line SC is stored (stored). In step S304, the focal length information of the lens stored in its own memory is stored in the display unit 321. indicate.

  In step S305, an irradiation angle is calculated based on the focal length information of the lens acquired in step S303, and movement information is given to the position signal terminal of the flash microcomputer 310 via the encoder 314 so that the calculated irradiation angle is obtained. .

  Next, in step S306, it is determined whether or not the charging current in the charging operation is equal to or less than a predetermined value (here, a2 (A)). The value of the charging current is detected using the above-described charging current detection circuit 702, and it is determined by the flash microcomputer 310 whether or not the charging current is equal to or less than a predetermined value based on the output of the charging current detection circuit 702. If the charging current is less than or equal to the predetermined value, the process proceeds to step S307, and an auxiliary light consumption current (iLED (LED)) can be secured, so an auxiliary light lighting permission signal indicating that auxiliary light can be turned on during moving image shooting. The camera microcomputer 101 is notified via the communication line SC. The camera microcomputer 101 receives the auxiliary light lighting permission signal and resumes moving image shooting, and the flash microcomputer 310 starts lighting the LED 325 in accordance with the resumption of moving image shooting. That is, the flash microcomputer 310 prohibits the LED 325 from emitting light when the charging current exceeds a predetermined value, and permits the LED 325 to emit light when the charging current does not exceed the predetermined value.

  In addition, the camera microcomputer 101 does not restart moving image shooting immediately after still image shooting, but does not restart moving image shooting until an auxiliary light emission permission signal is output from the flash microcomputer 310 in step S29 of FIG.

  In this way, when the auxiliary light consumption current (iLED (LED)) cannot be ensured by the charging operation (the charging current exceeds a predetermined value), the LED 325 is not turned on, and thus the light emission of the LED 325 does not fluctuate. Can be. Accordingly, it is possible to obtain a good moving image in which unevenness in brightness does not occur.

  In the above-described three embodiments, the camera system in which the strobe device 300 having the still image photographing illumination (discharge tube) and the moving image photographing illumination (LED) is mounted on the camera body 100 has been described. A camera with built-in lighting for still image shooting and lighting for moving image shooting may be used. In this case, the camera microcomputer 101 may perform the processing that the flash microcomputer 310 has performed. Further, at least part of the processing performed by the camera microcomputer 101 in the three embodiments described above may be performed by the flash microcomputer 310, and conversely, at least part of the processing performed by the flash microcomputer 310 may be performed by the camera microcomputer 101. Good.

DESCRIPTION OF SYMBOLS 100 Camera 101 Camera microcomputer 300 Strobe device 302 Charging circuit 306 Trigger circuit 307 Discharge tube 310 Strobe microcomputer 324 LED control circuit 325 LED

Claims (9)

A light-emitting device that emits light by using the same power source to emit a first light-emitting unit that performs flash emission and a second light-emitting unit that performs continuous emission;
A capacitor for accumulating electric charges for causing the first light emitting means to emit light using the power source;
Control means for controlling the light emitting operation of the second light emitting means, or the charging operation for accumulating electric charge in the capacitor,
The control means is configured such that the maximum value of the charging current in the charging operation when the second light emitting means is caused to emit light is greater than the maximum value of the charging current when the second light emitting means is not caused to emit light. A light-emitting device that is controlled to be small.   The control means sets an upper limit value smaller than the maximum value of the charging current when the second light emitting means is not lighted, and when the second light emitting means is lighted, the charging current is The light-emitting device according to claim 1, wherein the charging operation is controlled so as not to exceed the upper limit value.   The control means prohibits light emission of the second light emitting means when the charging current exceeds a predetermined value during the charging operation, and the charging current does not exceed the predetermined value. 2. The light emitting device according to claim 1, wherein the second light emitting unit is allowed to emit light. An imaging apparatus including a light emitting device that emits light from a first light emitting unit that performs flash emission and a second light emitting unit that performs continuous light emission using the same power source,
A capacitor for accumulating electric charges for causing the first light emitting means to emit light using the power source;
Control means for controlling the light emitting operation of the second light emitting means, or the charging operation for accumulating electric charge in the capacitor,
The control means is configured such that the maximum value of the charging current in the charging operation when the second light emitting means is caused to emit light is greater than the maximum value of the charging current when the second light emitting means is not caused to emit light. An imaging device that is controlled to be small.   The control means sets an upper limit value smaller than the maximum value of the charging current when the second light emitting means is not lighted, and when the second light emitting means is lighted, the charging current is The imaging apparatus according to claim 4, wherein the charging operation is controlled so as not to exceed the upper limit value.   The control means prohibits light emission of the second light emitting means when the charging current exceeds a predetermined value during the charging operation, and the charging current does not exceed the predetermined value. 5. The imaging apparatus according to claim 4, wherein the second light emitting unit is allowed to emit light. A camera system including a light emitting device that emits first light emitting means that emits flash light and a second light emitting means that performs continuous light emission using the same power source, and an imaging device that emits light and emits light. Because
A capacitor for accumulating electric charges for causing the first light emitting means to emit light using the power source;
Control means for controlling the light emitting operation of the second light emitting means, or the charging operation for accumulating electric charge in the capacitor,
The control means is configured such that the maximum value of the charging current in the charging operation when the second light emitting means is caused to emit light is greater than the maximum value of the charging current when the second light emitting means is not caused to emit light. A camera system that is controlled to be small.   The control means sets an upper limit value smaller than the maximum value of the charging current when the second light emitting means is not lighted, and when the second light emitting means is lighted, the charging current is The camera system according to claim 7, wherein the charging operation is controlled so as not to exceed the upper limit value.   The control means prohibits light emission of the second light emitting means when the charging current exceeds a predetermined value during the charging operation, and the charging current does not exceed the predetermined value. 8. The camera system according to claim 7, wherein the second light emitting unit is allowed to emit light.

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