JP5202391B2 - Imaging apparatus and method - Google Patents

Description

  The present invention relates to an imaging apparatus that projects light onto a subject using an LED or other light emitting element.

  In Patent Document 1, when a shooting instruction is given, AE control and AF control for a subject are performed, then strobe lighting control is started, and then imaging control is started. Therefore, even if the rising characteristic of the light amount when the strobe is turned on is gentle, it is possible to provide a margin before the start of the imaging control, and it is possible to suppress the shortage of light irradiated to the subject.

In Patent Document 2, the duty ratio of the pulse drive signal of the white LED is set to be relatively high at the start of opening the shutter. From the time when the shutter is fully closed until the time when the shutter is fully opened, the duty ratio of the pulse drive signal of the white LED is gradually lowered with time. When the predetermined time has elapsed and the shutter is fully opened, the duty ratio of the white LED pulse drive signal is kept constant for a predetermined period. Next, the duty ratio of the pulse drive signal of the white LED is gradually increased with the lapse of time from when the shutter starts to close to when it is fully closed.
JP 2006-31345 A JP 2005-99349 A

  Both Patent Documents 1 and 2 propose to provide a stable light quantity for exposure, but do not mention the power when driving the mechanical shutter. The power at the time of driving the mechanical shutter is large, and if the light emission continues during the exposure time, the instantaneous power consumption of the battery increases due to the overlap of the power consumption of the mechanical shutter and the power consumption by the light emission, and the battery is likely to fall.

  The present invention prevents the battery from falling due to the overlapping of the power consumption of the mechanical shutter driving and other mechanisms and the power consumption due to light emission.

  An image pickup apparatus according to the present invention includes an image pickup unit that photoelectrically converts an object image formed through an image pickup optical system and outputs an image, and an illumination unit that includes one or more light emitting elements that project the subject. A mechanical shutter capable of adjusting an exposure time of the image pickup device by opening and closing an optical path to the light receiving surface of the image pickup device, a power supply unit for supplying power to the image pickup unit, the illumination unit, and the mechanical shutter, and an illumination unit from the power supply unit A control unit that controls light emission timing and light emission amount based on power supply to the image sensor and exposure of the image sensor by opening and closing the mechanical shutter, and the control unit is at least during the opening and closing operation of the mechanical shutter. Stops flashing.

  According to the present invention, it is possible to prevent the battery from dropping due to the large current consumption by the shutter drive and the current consumption of the illumination.

  The control unit stops the light emission of the illumination unit before starting the closing operation of the mechanical shutter.

  The control unit starts light emission of the illumination unit before the exposure of the image sensor starts.

  In this way, it is possible to emit light with a delay from the start of light emission control to actual light emission in advance, and the amount of light emission during exposure can be increased.

  The control unit registers in the predetermined storage medium a delay time that is a time that is backed by a time lag from the lighting instruction to the illumination unit until the steady light emission of the illumination unit starts, and the delay time from the time when the mechanical shutter opens. A lighting instruction is given to the illumination unit at a timing that precedes only.

  In this way, steady light emission can be started without delay and without consuming unnecessary power for the start of exposure.

  An imaging apparatus according to the present invention includes an imaging unit that outputs a plurality of images by photoelectrically converting a subject image formed via an imaging optical system using an imaging element, and one or more light emitting elements that project the subject. An illumination unit, a mechanical shutter capable of adjusting an exposure time of the image sensor by opening and closing an optical path to the light receiving surface of the image sensor, a power source unit that supplies power to an electrical system other than the illumination unit and the illumination unit, and a power source unit A light emission timing and light emission amount control based on power supply from the light source to the illumination unit, and a control unit that controls exposure of the image sensor by opening and closing operation of the mechanical shutter, and the control unit includes an electrical system other than the illumination unit. The power consumption of the illumination unit is switched according to the fluctuation of the power consumption.

  In the present invention, the illumination can be maintained to such an extent that the power is not cut off.

  The electrical system other than the illumination unit includes a mechanical shutter.

  A capacitor capable of storing electricity with current from the power supply unit is provided, and the control unit outputs a current obtained by discharging the capacitor to the illumination unit when the mechanical shutter is opened and closed.

  The control unit adjusts the supply current from the capacitor to the illumination unit based on the adjustment time corresponding to the shutter operation delay of the mechanical shutter.

  An imaging method according to the present invention includes an imaging unit that photoelectrically converts an object image formed through an imaging optical system and outputs an image, and an illumination unit that includes one or more light emitting elements that project the subject. A mechanical shutter capable of adjusting an exposure time of the image pickup device by opening and closing an optical path to the light receiving surface of the image pickup device, a power supply unit for supplying power to the image pickup unit, the illumination unit, and the mechanical shutter, and an illumination unit from the power supply unit A control unit that controls light emission timing and light emission amount based on power supply to the image sensor and controls exposure of the image sensor by opening and closing the mechanical shutter. Stops flashing.

  An imaging method according to the present invention includes an imaging unit that outputs a plurality of images by photoelectrically converting a subject image formed through an imaging optical system using an imaging device, and one or more light emitting elements that project the subject. An illumination unit, a mechanical shutter capable of adjusting an exposure time of the image sensor by opening and closing an optical path to the light receiving surface of the image sensor, a power source unit that supplies power to an electrical system other than the illumination unit and the illumination unit, and a power source unit An imaging device comprising: a control unit that controls light emission timing and light emission amount based on power supply from the light source to the illumination unit; and a control unit that controls exposure of the image sensor by opening and closing the mechanical shutter. The power consumption of the illumination unit is switched according to the fluctuation of the power consumption.

  According to the present invention, it is possible to prevent the battery from dropping due to the large current consumption by the shutter drive and the current consumption of the illumination.

<First Embodiment>
FIG. 1 is a block diagram showing the internal configuration of a digital camera 1 (which may include a compact digital camera or a camera-equipped mobile phone).

  In the digital camera 1 of the present embodiment, all processing is controlled by the system control circuit 110. Control units such as a release button 104, a mode dial 105, a single shooting / continuous shooting switch 106, and the like are connected to the input unit of the system control circuit 110, and an operation signal is generated by the operation of any of these controls. When supplied to the system control circuit 110, processing corresponding to any one of these operators is started.

  In the digital camera 1, a removable storage medium 200 such as a memory card is loaded in the medium loading chamber 100A, and image data representing a photographed image is recorded in the memory card 200 loaded in the medium loading chamber 100A. Therefore, a storage medium attachment / detachment detection means 108 for detecting whether a memory card as a storage medium is mounted in the medium loading chamber 100A is provided. On the back side, image display ON / OFF switch 107 and image display unit opening / closing detection means 109 for detecting opening / closing of a protective door for protecting the surface of the display panel provided on the back side are also provided. Signals from the storage medium attachment / detachment detection means, the image display ON / OFF switch 107, and the image display section open / close detection means 109 are also supplied to the system control circuit 110, and the system control circuit 110 receives these signals and appropriately processes them. Is also supposed to run. Further, the system control circuit 110 instructs the zoom control means 1020 to move the zoom lens in the photographing lens 1021 in response to an operation of a zoom switch (not shown), or to the distance measurement control means 1030 in accordance with the distance measurement result. The focus lens in the taking lens 1021 is also moved by instructing.

  Further, in the system control circuit 110, TTL photometry is performed together with the TTL distance measurement based on image data generated by the solid-state imaging device 120 such as a CCD. Depending on the photometric result of this TTL photometry, the system control circuit 110 instructs the exposure control means 1040 to adjust the aperture diameter of the aperture 1041 to the exposure control means, or at the time of shooting, the TTL photometric result is obtained. Based on this, the light emission amount control means 112 in the light emission means 11 is instructed to drive each of the plurality of LEDs 114 to the LED drive circuit 113, so that the photographing auxiliary light (steady light, not flash) is emitted from the plurality of LEDs 114 to the subject. Or irradiating it. The LED 114 may be replaced with another light emitting element, for example, a plasma element.

  The mechanical shutter 16 is composed of a light-shielding plate that can be moved forward and backward in the incident optical path of the solid-state image sensor 120, and shields / opens the incident optical path of the solid-state image sensor 120 by electric drive means 16 a that is electronically controlled via the system control circuit 110. This is an electronically controlled shutter that controls the exposure time. As the electric driving means 16a which is an opening / closing mechanism of the mechanical shutter 16, any one can be adopted as long as it consumes the power of the battery Bt at least when electronic control of shielding of the incident light path is performed. For example, a shutter blade opening / closing mechanism using an actuator (for example, one described in Japanese Patent Application Laid-Open No. 2004-118024 by the present applicant) can be mentioned. Alternatively, a coil spring for biasing the rotation axis of the drive lever integrated with the permanent magnet in one rotation direction is attached to this rotation shaft, and the rotation axis of the drive lever is biased in one rotation direction by this coil spring. The blades may be closed by the spring force of the coil spring and the electromagnetic driving force (for example, those described in Japanese Patent Application Laid-Open No. 2003-15186). Furthermore, the electric drive means 16a may be one that consumes the power of the battery Bt before the electronic control of the shielding of the incident optical path is performed (for example, the one described in JP-A-2002-369042). In short, any electronically controlled shutter that consumes power at a desired driving timing may be used.

  By supplying a relatively small current to the central LED of the plurality of LEDs 114 and supplying a relatively large current to the peripheral LED, the central LED is fatigued due to the temperature rise due to the emission of the photographing auxiliary light. Eventually it is prevented from breaking.

  Here, the outline of the photographing process of the digital camera 1 having the light emitting means including the plurality of LEDs 114 as a light emitting source will be described.

  In the present embodiment, when the power switch of the digital camera 1 is turned on, the overall operation of the digital camera 1 is comprehensively controlled by the system control circuit 110 according to the procedure of the overall processing program in the nonvolatile memory 110A. Processing begins. In this example, a power switch (not shown) of the digital camera 1 is turned on in order to suppress battery power consumption, and the system control circuit 110 (the system control circuit 110 is always supplied with power from the battery Bt) is powered. Only when it is detected that the switch has been turned on, power is supplied from the battery Bt to each block via the power control means 111b.

  The digital camera 1 is provided with a photographing lens 1021 such as a focus lens and a zoom lens, and a diaphragm 1041 for adjusting the amount of light. In this example, a lens barrier 1011 for protecting the lens is shown. When the power switch is turned on, the lens barrier 1011 is released and the photographing lens 1021 is exposed on the surface. ing.

  When the mode dial 105 is switched to the photographing side when the power switch is turned on, the subject image first formed on the CCD solid-state photographing element 120 through the photographing lens 1021 exposed on the surface is the timing. Based on the timing signal from the generation circuit 121, the data is thinned out at predetermined intervals (for example, every 33 ms) and output. The output image signal is converted from an analog image signal to a digital image signal by the A / D conversion circuit 130, and the digital image signal is guided to the image processing circuit 140 under the control of the memory control unit 111a. The image processing circuit 140 separates the RGB image signals into R, G, and B signals, and the R, G, and B signals are guided to the system control circuit 110 under the control of the memory control unit 111a. The system control circuit 110 performs white balance adjustment, γ correction, and conversion to a YC signal, and is then led to the image display memory 151 under the control of the memory control unit 111a as an image signal representing a through image. The YC signal is stored in the image display memory 151. The image signal for one frame stored in the image display memory 151 is read out by the memory control unit 111a, guided to the D / A conversion circuit 160, converted into an analog image signal, and then supplied to the image display unit 150. Is done. In this example, an image display memory 151 is provided so that a new image signal can be supplied to the image display unit 150 at predetermined intervals, and a through image signal for at least two frames is provided in the image display memory 151. Is stored and the through image signal is first-in first-out, so that the through image switching timing can be adjusted well.

  In the present embodiment, an example is shown in which the white balance adjustment and γ correction, and as described above, photometry and distance measurement are performed by the system control circuit 110, and each color signal of R, G, B is an image processing circuit. 140 is supplied to the system control circuit 110 and is subjected to white balance adjustment and γ correction in the system control circuit 110 and then converted to a YC signal and supplied to the image display memory, while the YC signal Based on the Y signal, photometry, distance measurement, etc. are performed to control the aperture of the diaphragm 1041 and the placement control of the focus lens in the photographing lens 1021 at the focal point.

  Here, the operation of each unit will be described in detail along with the flow of the through image signal.

  In accordance with a timing signal from the timing generation circuit 121 (for example, every 33 ms), an image signal representing a subject image formed on the light receiving surface on the solid-state imaging device 120 by the photographing lens 1021 is used as a through image signal, and a subsequent A / D. The data is output to the conversion circuit 130. The through image signal converted from the analog image signal to the digital image signal by the A / D conversion circuit 130 is guided to the image processing circuit 140 under the control of the memory control unit 111a. The image processing circuit 140 separates the R color, G color, and B color signals and supplies them to the color temperature detection circuit 141, or the R, G, and B color signals are supplied to the system control circuit 110. To do. In the color temperature detection circuit 141, each color temperature is detected, and a gain corresponding to each color temperature is set in each color amplifier of the white balance adjustment unit in the system control circuit 110.

  R. G. The B signals are supplied to the system control circuit 110, and the white balance adjustment unit adjusts the amplitude ratio of each color signal to adjust the white balance, and further γ-correct each R, G, B color signal. Are converted into YC signals by the color conversion matrix. The YC signal is guided and stored in the image display memory 151 under the control of the memory control unit 111a. As described above, at least two frames of image signals are stored in the image display memory 151. Of the two frames of image signals, one frame of image signals stored at the old time is D. The A / A conversion circuit 160 converts the signal into an analog signal, supplies the analog signal to the image display unit 150, and displays the through image on the display screen.

  Further, the system control circuit 110 instructs the distance measurement control means 1030 based on the distance measurement result in the TTL distance measurement unit in the system control circuit to arrange the focus lens in the photographing lens 1021 at the focal point, When a zoom switch (not shown) is operated, the zoom control unit 1020 is instructed to arrange the zoom lens in the photographing lens 1021 at a position corresponding to the zoom magnification by the operation of the zoom switch.

  In this way, when the release button 104 is pressed while a through image with a zoom magnification corresponding to the operation position of the zoom switch, which is always in focus, is displayed, the photographing process is started.

  The system control circuit 110 causes the timing generation circuit 121 to supply an exposure start signal toward the solid-state imaging device 120 at the timing when the release button 104 is pressed. At this time, if the system control circuit 110 determines that photographing auxiliary light needs to be emitted based on the photometric result, the light emitting amount control means 112 is instructed to synchronize the depression of the release button 104 to the plurality of LEDs 114. Light is emitted.

  In this way, when the field brightness is bright, the shooting assist light is not emitted, and when the field brightness is dark, the shooting assist light is emitted and shooting is performed. Then, the system control circuit 110 issues an instruction to the timing generation circuit 121. Then, an exposure end signal is supplied toward the solid-state image sensor 120 after a predetermined shutter time, and an image signal is output from the solid-state image sensor 120 to the A / D conversion circuit 130 in synchronization with the exposure end signal. In the A / D conversion circuit 130, the analog image signal output from the solid-state imaging device 120 is converted into a digital image signal, and the digital image signal is further stored in the memory via a bus under the control of the memory control unit 111a. 180. When all the image signals composed of all the pixels included in the solid-state imaging device 120 are stored in the memory 180, this image signal is read out under the control of the system control circuit 110, and the white balance is adjusted by the system control circuit 110. And gamma correction are performed. Further, after the image signal subjected to white balance adjustment and gamma correction is converted into a YC signal in the system control circuit 110, the YC signal for one frame is compressed / compressed via the bus under the control of the memory control unit. An image signal composed of a YC signal supplied to the decompression circuit 190 is compressed and stored in the storage medium 200, here a memory card.

  In addition, when the antenna 117 is connected to the connector on the side surface of the camera body via a cable, a communication means that can perform wireless communication with the outside, a display unit 150 that conveys the operation content to the user, a memory 110B, and the like are also provided. Has been.

  FIG. 2 shows the main part of the auxiliary light emitting unit 11 and its peripheral circuits. The current from the battery Bt is once input to the light emission amount control means 112. Under the control of the system control circuit 110, the light emission amount control means 112 inputs a light emission control signal together with the current to the LED drive circuit 113. The light emission control signal includes a lighting signal DH and a light extinction signal DL, and one of these is input to the LED drive circuit 113. The LED drive circuit 113 starts lighting the LED 114 when the lighting signal DH is input, and ends the lighting of the LED 114 when the extinguishing signal DL is input. The system control circuit 110 instructs the light emission amount control unit 112 to output the lighting signal DH in response to the release button 104 being fully pressed, and outputs the light emission signal DL after the predetermined exposure time has elapsed from the instruction of the lighting signal DH. The control unit 112 is instructed. The exposure time (shutter speed) is determined by the system control circuit 110 in accordance with a program diagram stored in advance in the nonvolatile memory 110A.

  The configuration of the LED drive circuit 113 is the same as a general example. The resistor R connected in series with the LED 114 is used to set the drive current of the LED 114. The value of this resistance is set based on the current value to be passed through the LED 114 and the value of the feedback voltage FB necessary for controlling the step-up / step-down circuit 113b. For example, when the current flowing through the LED 114 is 100 mA and the required feedback voltage is 1.23 V, the value of the resistance R is 12Ω. The logic circuit 113a controls the current supplied to the LED 114 by the step-up / step-down circuit 113b in accordance with the lighting signal DH or the light-off signal DL, and causes the LED 114 to blink.

  FIG. 3 is a time chart illustrating the timing of exposure control by the exposure control unit 1040 and the light emission control by the light emission amount control unit 112, which are comprehensively controlled by the system control circuit 110. The system control circuit 110 instructs the light emission amount control unit 112 to start lighting (output the lighting signal DH) at a time (for example, 2 seconds) that is a predetermined time later than the exposure control unit 1040 to start exposure. To do. Upon receiving the lighting start instruction from the system control circuit 110, the light emission amount control means 112 outputs a lighting signal to the LED driving circuit 113, and the LED driving circuit 113 lights the LED 114 in response to this, but the lighting signal DH Some time lag TL occurs until the LED 114 starts steady lighting from the output of the above. This is due to the reaction time of the logic circuit 113a and the step-up / step-down circuit 113b of the LED drive circuit 113.

  If exposure starts before the LED 114 starts steady lighting, it will lead to taking a failed photo due to a light emission failure. Therefore, the output of the lighting signal DH is started at a timing T0 that is earlier than the exposure start timing T1 by a time corresponding to the time lag TL. In this way, exposure starts when the LED 114 starts steady lighting, and it is possible to prevent the occurrence of failure photos due to poor light emission, particularly failure photos during high-speed shutter. Note that the exposure end and the turn-off signal DL may be at the same timing (T2).

Second Embodiment
In the first embodiment, if the time lag TL is accurately measured, the measurement result is registered in the nonvolatile memory 110A, and light emission is started at a timing T0 that is back by the registered time lag TL from the exposure start timing T1, Steady lighting at the start of exposure can be secured.

  FIG. 4 shows a system for measuring the time lag TL and registering it in the camera 1. This system includes a camera 1, a light receiving unit 2, and a personal computer (PC) 3.

  The light receiving unit 2 is configured with a known photosensor, and outputs a signal indicating the amount of light received from the LED 114 of the camera 1 to the PC 3.

  When the system control circuit 110 of the camera 1 receives the setting of the “time lag measurement mode” via the mode dial 105, the lighting signal DH output from the light emission amount control unit 112 in response to the full press of the release button 104 is sent to the PC 3. The communication means 116 is controlled to transmit.

  The PC 3 calculates the difference between the timing at which the amount of received light notified from the light receiving unit 2 starts to become substantially constant (stabilization start timing Tc) and the timing (Ti) at which the lighting signal DH is received from the camera 1. To the camera 1 as an adjustment value.

  FIG. 5 shows the reception timing Ti of the lighting signal DH from the light receiving unit 2, the light emission start timing Ts of the LED 114, the steady start timing Tc at which the received light amount from the LED 114 becomes substantially constant, and the received light amount along the time axis. Shows the transition. The intervals of Ti to Ts and Ts to Tc are each about 1 ms. The camera 1 regards the difference between Tc and Ti as TL.

  The system control circuit 110 of the camera 1 registers the adjustment value received from the PC 3 in the nonvolatile memory 110A as the time lag TL, and starts the light emission at the timing T0 that is backed by the registered time lag TL from T1. To instruct. By doing so, it is possible to prevent generation of a failed photograph due to light emission that is too slow or wasteful power consumption due to light emission that is too early. Furthermore, the variation in the light emission timing for each solid of the camera 1 can also be adjusted for each solid.

  The camera 1 itself may receive the light reception signal from the light receiving unit 2 instead of the PC 3, and the difference between the timing and the generation timing of the lighting signal DH by the light emission amount control means 112 may be calculated.

<Third Embodiment>
In the first and second embodiments, a large amount of electric power is consumed when the shutter 16 is driven to close, but when this overlaps with the electric power consumption due to the light emission of the LED 114, the battery is likely to fall if the remaining amount of the battery Bt is small. In order to prevent this, the power consumption is smoothed by increasing the number of images that can be shot by driving the shutter 16 closed after the light emission of the LED 114 is stopped.

  Specifically, as shown in FIG. 6, the system control circuit 110 controls the light emission amount control means so that the light emission of the LED 114 is stopped at the timing Te and the shutter drive is started at the timing Tf later than that.

  FIG. 7 is a flowchart showing a flow of control for starting and stopping the light emission of the LED 114 by the system control circuit 110.

  In S1, acquisition and display of a through image is started in response to the mode dial 105 accepting the setting of the shooting mode.

  In S2, it is determined whether or not the release button 104 is half-pressed. If Yes, the process proceeds to S3, and if No, this determination is repeated.

  In S3, AE (automatic exposure control) is started.

  In S4, the LED 114 starts to emit light.

  In S5, AF (automatic focus control) is started.

  In S6, the light emission of the LED 114 is stopped.

  In S7, it is determined whether or not the release button 104 has been fully pressed. If Yes, the process proceeds to S9. If No, the process proceeds to S8.

  In S8, it is determined whether or not the release button 104 is half-pressed. If Yes, the process returns to S2. If No, the process returns to S7.

  In S9, pre-light emission of the LED 114 is performed to calculate the reflected light amount of the photographing auxiliary light during the main light emission.

  In S10, based on the reflected light amount calculated in S9, the light emission time of the LED 114 that reaches the specified light amount is determined, and the LED 114 is caused to emit light until that time elapses. This is because the light receiving amount per unit time of the LED 114 at the time of pre-emission is measured by a dimming sensor (not shown) of the camera 1, and the received light amount per unit time is integrated from the light emission start point by the system control circuit 110. Alternatively, it may be replaced by a method of stopping the light emission of the LED 114 when the integrated value reaches a specified light amount. The timing T0 in FIG. 6 corresponds to the LED 114 light emission start time determined in this step, and the timing Te corresponds to the LED 114 light emission end time determined in this step.

  In S11, exposure of the solid-state image sensor 120 is started. This timing corresponds to T1 in FIG.

  In S12, the light emission of the LED 114 is stopped in response to the accumulated light amount of the LED 114 reaching the predetermined light amount X. This timing corresponds to Te in FIG.

  In S13, the closing operation of the shutter 16 is started at a timing later than Te. This timing corresponds to Tf in FIG. Note that the timing at which the shutter 16 is completely closed corresponds to T2 in FIG. 6, and the exposure (charge accumulation) of the solid-state imaging device 120 is stopped at this timing. Since there is a certain length of time from the start to the end of the closing operation of the shutter 16 and the ratio of the exposure time is large, the closing operation of the shutter 16 is performed at a timing Tf before the target exposure end T2. In addition, it is necessary to stop light emission at timing Te before timing Tf.

  In S14, it is determined whether or not the shooting mode setting has been canceled. In the case of Yes, this process is complete | finished, and in No, it returns to S2.

  Unlike a strobe such as a xenon tube that is fed from a capacitor, the LED 114 requires constant power supply when it is lit. Therefore, if the LED 114 overlaps with another mechanism that consumes a large amount of power, in this case the closing operation of the shutter 16, the battery Bt Easy to fall. However, in the processing described above, the light emission of the LED 114 is terminated at a timing Te before the timing Tf at which the closing operation of the shutter 16 starts, so that the duplication of both can be avoided.

<Fourth embodiment>
In the third embodiment, the shutter closing drive is started after the light emission of the LED 114 is completely stopped. However, the light emission may be continued within a range in which the battery Bt does not drop after the shutter 16 starts the closing drive.

  FIG. 8 shows a timing chart of the closing drive of the shutter 16 and the continued light emission of the LED 114. The intensity of light emitted from the LED 114 is approximately proportional to the amount of current. Therefore, for example, if the amount of current supplied to the LED 114 is changed from H = 100 mA to L = 50 mA, the light intensity per unit time when supplying 100 mA is expressed as W, and light per unit time when supplying 50 mA. The strength of is about W / 2. Note that the values of H and L are arbitrary. In particular, L is the sum of the current consumption of the shutter 16 and other peripheral devices (not limited to the shutter 16 but also the image sensor 120 and the image display unit 150). It does not have to exceed the current.

  In FIG. 8, instead of stopping the light emission at the timing Te described in the third embodiment, the amount of current supplied to the LED 114 is switched from H to L. From this point of time, the light intensity of the LED 114 becomes W / 2, but since the lighting is still continued, the light projection time in the exposure time can be increased as compared with the third embodiment. Therefore, it is possible to prevent an increase in the proportion of the non-lighting time that occupies the exposure time, particularly when shooting with a high-speed shutter.

  When the cumulative amount of light emission of the LED 114 reaches a specified light amount X, that is, when the time length when the current is supplied with H is ta and the time length when the current is supplied with L is tb, X = ta × The current supply to the LED 114 may be stopped at the timing Ts when W + tb × W / 2.

<Fifth Embodiment>
Since a large current is consumed when the shutter 16 is driven, the battery Bt is likely to be dropped if power is simultaneously consumed for the light emission of the LED 114. Therefore, as shown in FIG. 9, when the shutter 16 is driven, it is preferable to supply power to the LED 114 not from the battery Bt but from the capacitor C. The storage and discharge of the capacitor C is controlled by the light emission amount control means 112 in accordance with an instruction from the system control circuit 110. The capacitor C is charged by connecting the battery Bt to the capacitor C.

  FIG. 10 is a timing chart of storage and discharge of the capacitor C controlled by the system control circuit 110.

  In the present embodiment, the light emission amount control unit 112 switches the power supply source to the LED 114 from the battery Bt to the capacitor C at the timing Te described in the third embodiment. The capacitor C needs to have a capacity that allows the LED 114 to continue to emit light at least from the shutter drive start Tf to the exposure end T2.

  The capacity of the capacitor C may be smaller than that of a conventional xenon tube strobe capacitor. The conventional capacitor needs to have a large capacity and increases in size in order to supply all the electric power necessary for light emission. On the other hand, in the present embodiment, a large-sized capacitor is not necessary because power in a range where the LED 114 needs to emit light is supplied while the shutter 16 is driven.

<Sixth Embodiment>
The time and speed from the start of driving of the shutter 16 to the end of exposure vary depending on variations in the mechanism and motor, which becomes an obstacle when controlling the exposure time. Therefore, it is necessary to adjust the interval between the exposure end and the shutter drive start signal (shutter operation delay adjustment), which is conventionally known (for example, Japanese Patent Application Laid-Open No. 2008-244622).

  When this adjustment is applied to the camera 1 of the first to fifth embodiments, the driving start timing Tf of the shutter 16 changes (see FIG. 11). If so, the exposure time changes, and proper exposure may not be obtained. Therefore, the system control circuit 110 adjusts the current supplied to the LED 114 in accordance with the adjustment of the interval.

  For example, the system control circuit 110 sets I0 = 100 mA as a default supply value when there is no interval adjustment, and if the interval is adjusted to be short, a value obtained by adding a corresponding adjustment value α (> 0) to I0, If the interval is adjusted to be longer, a value obtained by subtracting the corresponding adjustment value β (> 0) from I0 is instructed to the light emission amount control means 112 as the final current to the LED 114. The light emission amount control means 112 supplies the current instructed from the system control circuit 110 to the LED 114 from the battery Bt or the capacitor C. The current supply stop (lighting end) timing is Te. When the supply current is I0 + α, the amount of light per unit time increases, and underexposure can be prevented. On the other hand, when the supply current is I0-β, the amount of light per unit time decreases, so that useless power consumption can be suppressed.

  In the case of the fifth embodiment, the charging voltage to the capacitor C is increased in order to obtain the adjustment value α. However, it is sufficient if a current corresponding to the adjustment value α can be obtained, and it is not always necessary to fully charge the capacitor C.

  In this way, proper exposure can be obtained even when the shutter drive variation is adjusted.

<Seventh embodiment>
The light emission of the LED 114 may be stopped not only when the shutter 16 is closed but also when the shutter 16 is opened. For example, there may be a case where LED lighting that continues to be lit unless otherwise instructed by the user is temporarily stopped while the shutter 16 is being opened.

Camera block diagram The figure which shows the principal part of a light emission means and its peripheral circuit Time chart of light emission control Diagram showing a system for measuring time lag and registering it with the camera Diagram illustrating the start timing of steady state The figure which illustrated LED light emission stop timing Te, shutter drive start timing Tf The flowchart which shows the flow of control of light emission start and stop of LED Timing chart of shutter closing drive and LED light emission continuation The figure which shows the principal part of the electric circuit which has a capacitor | condenser which can supply electric power to LED Capacitor C storage / discharge timing chart The figure which illustrated a mode that the timing Tf of the drive start by shutter operation delay adjustment changes

DESCRIPTION OF SYMBOLS 1: Digital camera, 100: Lens barrel, 101: Finder, 102: Light emission window, 104: Release button, 105: Mode dial, 106: Single shooting / continuous shooting switch, 107: Image display ON / OFF switch, 110 : System control circuit, 120: CCD solid-state imaging device, 130: A / D conversion circuit, 140: Image processing circuit, 141: Color temperature measurement circuit, 11: Auxiliary light emission unit, 112: Light emission amount control means, 113: LED Drive circuit, 114: LED

Claims (4)

An imaging unit that photoelectrically converts an object image formed through an imaging optical system by an imaging element and outputs an image; and
An illumination unit having one or a plurality of light emitting elements that project a subject;
An electronically controlled mechanical shutter capable of adjusting the exposure time of the image sensor by opening and closing an optical path to the light receiving surface of the image sensor;
A power supply unit that supplies power to the imaging unit, the illumination unit, and the mechanical shutter;
A control unit that controls light emission timing and light emission amount based on power supply from the power supply unit to the illumination unit, and controls exposure of the image sensor by opening and closing operation of the mechanical shutter;
With
The control unit stops light emission of the illumination unit at least during the opening / closing operation of the mechanical shutter, stops light emission of the illumination unit before starting the closing operation of the mechanical shutter, and before starting exposure of the image sensor. Instructing the start of light emission of the illumination unit, and registering in a predetermined storage medium a delay time that is a time that goes back by a time lag from the lighting instruction to the illumination unit until the steady light emission of the illumination unit starts, An imaging apparatus that issues a lighting instruction to the illumination unit at a timing preceding the start time of opening of the mechanical shutter by the delay time . An imaging unit that photoelectrically converts an object image formed through an imaging optical system using an imaging element and outputs a plurality of images; and
An illumination unit having one or a plurality of light emitting elements that project a subject;
A mechanical shutter capable of adjusting an exposure time of the image sensor by opening and closing an optical path to a light receiving surface of the image sensor;
A power supply unit that supplies power to an electrical system other than the illumination unit and the illumination unit;
A control unit that controls light emission timing and light emission amount based on power supply from the power supply unit to the illumination unit, and controls exposure of the image sensor by opening and closing operation of the mechanical shutter;
A capacitor capable of storing electricity by current from the power supply unit;
With
The control unit switches the power consumption of the illumination unit according to a change in power consumption of an electrical system other than the illumination unit including the mechanical shutter, and is obtained by discharging the capacitor during the closing operation of the mechanical shutter. An imaging device that outputs a current to the illumination unit and adjusts a supply current from the capacitor to the illumination unit based on an adjustment time corresponding to a shutter operation delay of the mechanical shutter . An imaging unit that photoelectrically converts an image of a subject formed through an imaging optical system and outputs an image, an illumination unit that includes one or more light emitting elements that project the subject, and a light receiving surface of the imaging device A mechanical shutter capable of adjusting the exposure time of the imaging device by opening and closing an optical path to the imaging device, a power supply unit for supplying power to the imaging unit, the illumination unit, and the mechanical shutter, and the power supply unit to the illumination unit An image pickup apparatus comprising: a light emission timing and a light emission amount control based on power supply; and a control unit that controls exposure of the image pickup device by the opening and closing operation of the mechanical shutter, and at least during the opening and closing operation of the mechanical shutter, stop light emission of the lighting unit, before the start of the closing operation of the mechanical shutter, the light emission of the illumination unit stops, before starting exposure of the imaging device, prior to The mechanical shutter is instructed to start light emission, and a delay time, which is a time that is backed by a time lag from the lighting instruction to the illumination unit to the start of steady light emission of the illumination unit, is registered in a predetermined storage medium, and the mechanical shutter An imaging method in which a lighting instruction is given to the illumination unit at a timing preceding the start time of the opening operation by the delay time . An imaging unit that photoelectrically converts a subject image formed through an imaging optical system to output a plurality of images by an imaging device, an illumination unit that includes one or more light emitting elements that project the subject, and the imaging device A mechanical shutter capable of adjusting an exposure time of the image sensor by opening and closing an optical path to the light receiving surface, a power supply unit for supplying power to the electrical system other than the illumination unit and the illumination unit, and the illumination from the power supply unit A control unit that controls light emission timing and light emission amount based on power supply to the unit, control of exposure of the image sensor by opening and closing operation of the mechanical shutter, and a capacitor that can be charged by a current from the power source unit. comprising the imaging apparatus switches the power consumption of the illumination unit in accordance with a variation in power consumption of the electrical system other than the illumination unit including the mechanical shutter, the Mechanica During the closing operation of the shutter, and outputs a current obtained by the discharge of the capacitor to the illumination unit, to adjust the current supplied to the illumination unit from the condenser based on the adjustment time corresponding to the shutter operation delay of the mechanical shutter Imaging method.

Images