JP2015169923A - imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems that an electric double layer capacitor is subjected to limitation of applied voltage and application time, and applying high voltage required in imaging of a still image for a long time results in deterioration of capacity, and therefore, when an LED is used as a light emission element of a stroboscopic device, and the electric double layer capacitor is mounted on a camera which uses stroboscopic during imaging of a still image and auxiliary light during AF time, there is a problem of deterioration of capacity of the electric double layer capacitor.SOLUTION: A power storage element is charged to voltage in which a light emission element can light up as AF auxiliary light during starting time, and the power storage element is charged to voltage in which stroboscopic light emission is possible when it is determined that stroboscopic light emission imaging is performed.

Description

  The present invention relates to an image pickup apparatus provided with a large capacity capacitor in a strobe device.

  Conventionally, there are various types of strobe charging circuits known, and as in Patent Document 1, the strobe for shooting a still image and the video light for shooting a movie are combined into one strobe device to simplify shooting. A camera has been proposed. In recent years, there has been proposed a camera that uses an LED as a light emitting element of a strobe device and uses both a strobe for still image shooting and an auxiliary light for AF. Also, a strobe device equipped with an electric double layer capacitor (EDLC) has been devised to allow a large current to flow through the LED during still image shooting.

Japanese Patent No. 3698600

  However, the electric double layer capacitor has restrictions on the applied voltage and the application time, and if a high voltage required for still image shooting is applied for a long time, it causes a capacity deterioration (FIG. 4). Therefore, when an LED is used as a light emitting element of a strobe device and an electric double layer capacitor is mounted on a camera that combines a strobe for still image shooting and an auxiliary light for AF, there is a problem of capacity deterioration of the electric double layer capacitor. It was.

The imaging device of the present invention includes a power source for supplying power of a primary battery and a secondary battery,
Boosting means for boosting the voltage of the power supply;
Boost control means for controlling the boost circuit;
A storage element connected to a booster circuit and storing electric charge from a power supply;
A light-emitting element that combines the strobe for still image shooting, the AF auxiliary light, and the self-timer warning light,
A light emission control means for controlling the light emission amount of the light emitting element;
In an imaging apparatus comprising:
The step-up control means charges the power storage element to a voltage at which the light emitting element can be turned on as AF auxiliary light at the time of start-up, and charges to a voltage at which strobe light emission is possible when it is determined to perform strobe light emission photography. Yes.

  According to the present invention, it is possible to provide a camera equipped with an LED strobe that combines a strobe during still image shooting and an auxiliary light during AF without promoting the capacity deterioration of the electric double layer capacitor.

It is a figure which shows the structure about an example of an imaging device provided with the strobe device by the 1st Embodiment of this invention. Flowchart for explaining the operation of the imaging apparatus shown in FIG. The figure which showed the charging voltage to the electrical storage element 7, and the light emission current of the light emitting element 2 Electrical characteristics of electric double layer capacitor

[Example 1]
FIG. 1 is a diagram showing the configuration of an example of an imaging apparatus including a strobe device according to the first embodiment of the present invention.

  The imaging device 1 includes a light emitting element (light emitting unit) 2 such as an LED.

  The light emitting element 2 emits light for AF auxiliary light use and strobe use at the time of photographing, and the light emission control circuit 4 of the overall control unit 3 is connected to the cathode.

  The overall control unit 3 controls the entire imaging apparatus 1. Here, only control lines necessary for charging and light emission are shown, and for example, control lines for controlling the camera unit 8 are omitted. As illustrated, the overall control unit 3 includes a light emission control circuit 4 and a boost control circuit 5.

  The light emission control circuit 4 controls the timing and current value to flow to the light emitting element 2, turns on at the timing of light emission, and controls a switch (not shown) for flowing current to the light emitting element 2 and the current flowing to the light emitting element 2. A variable resistor (not shown) is included.

  The step-up control circuit 5 performs output voltage setting and charging current setting of the step-up circuit 6 and controls ON / OFF of a switching element (not shown) of the step-up circuit 6.

  The booster circuit 6 has an output connected to the anode of the light emitting element 2 and the power storage element 7, boosts the voltage of the battery power supply 9 to a set output voltage according to the control of the boost control circuit 5, and charges the power storage element 7. .

  The electric storage element 7 supplies electric charges to the light emitting element 2 at the time of light emission, and for example, a large capacity element such as an electric double layer capacitor is used.

  The camera unit 8 captures a subject and obtains image data.

  The battery power supply 9 supplies power to the booster circuit 6 and supplies power to the entire imaging apparatus 1 through a power supply circuit (not shown). For example, a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, or a Li battery is used.

  FIG. 2 is a flowchart for explaining the operation of the imaging apparatus shown in FIG.

  FIG. 3 is a diagram showing the charging voltage to the storage element 7 and the light emission current of the light emitting element 2.

  With reference to FIGS. 1 to 3, when a power button (not shown) is turned on in the imaging apparatus 1, the camera unit 8 is activated. At the time of activation, the camera unit 8 is activated in a mode such as shooting or reproduction in accordance with a mode change switch provided in an operation unit (not shown). That is, when the mode switch is set to the shooting mode, the camera unit 8 is activated in the shooting mode.

  When the camera unit 8 is activated in the shooting mode, the overall control unit 3 outputs a charge signal to the boost control circuit 5 (S201 in FIG. 2).

  When the charging signal is turned on, the boost control circuit 5 starts to turn on / off the switching element of the booster circuit 6 and starts charging the power storage element 7 (S202 in FIG. 2, T1 in FIG. 3).

  The step-up control circuit 5 detects the output voltage of the step-up circuit 6 (charging voltage of the storage element 7), and performs charging to a predetermined arbitrary voltage V1 (S203 in FIG. 2). The voltage V1 is a voltage at which the light emitting element 2 can be turned on for AF auxiliary light use. The voltage V1 is a forward voltage (VF) of the light emitting element 2 generated when a current to be emitted as AF auxiliary light is supplied to the light emitting element 2, a drop voltage of a switch and a resistance component in the light emission control circuit 4, and a booster circuit 6 It is determined from the voltage drop due to the wiring resistance between the light emitting element 2 and the light emission control circuit 4.

  When the charging voltage of the storage element 7 reaches V1, the boost control circuit 5 stops turning on / off the switching element of the boost circuit 6 and stops charging the storage element 7 (S204 in FIG. 2, T2 in FIG. 3). ).

  The overall control unit 3 performs input confirmation of a half-press of a release button (not shown) as an operation unit (S205 in FIG. 2).

  If the half-press input of the release button cannot be confirmed in S205, the process returns to S203 and is periodically charged so that the charging voltage of the storage element 7 becomes V1.

  When the half-press input of the release button is confirmed in S205 (T3 in FIG. 3), the overall control unit 3 uses the light emitting element 2 as AF auxiliary light when performing AF based on the image information from the camera unit 8. It is determined whether or not to turn on (S206 in FIG. 2).

  If it is determined in S206 that the light emitting element 2 is turned on as AF auxiliary light, the light emission control circuit 4 supplies a current to the light emitting element 2 at a predetermined current value I1 to turn on the light emitting element 2 (S207 in FIG. 2). In FIG. 3, T4 to T5). The current value I1 is a low current value of about 30 mA to 100 mA.

  The overall control unit 3 performs AF and AE processing based on the image information of the camera unit 8 when the light emitting element 2 is turned on as AF auxiliary light (S208 in FIG. 2).

  If it is determined in S206 that the light emitting element 2 is not turned on as AF auxiliary light, the process proceeds to S208 without performing S207.

  The overall control unit 3 determines whether or not to perform strobe light emission at the time of shooting based on the result of the AE process in S208 (S209 in FIG. 2).

  When it is determined in S209 that strobe light emission is performed during shooting, the boost control circuit 5 changes the output voltage set value of the boost circuit 6 to a predetermined arbitrary voltage V2 (S210 in FIG. 2, T6 in FIG. 3). ). The voltage V2 is a voltage at which the light emitting element 2 can be turned on for strobe use, and is higher than the voltage V1.

  When the output voltage set value of the booster circuit 6 is changed to the voltage V2, the overall control unit 3 outputs a charge signal to the booster control circuit 5 (S211 in FIG. 2, T6 to T7 in FIG. 3).

  When the charging signal is turned on, the boost control circuit 5 starts to turn on / off the switching element of the boost circuit 6 and starts charging the power storage element 7 (S212 in FIG. 2, T6 in FIG. 3).

  The step-up control circuit 5 detects the output voltage of the step-up circuit 6 (charging voltage of the storage element 7), and performs charging up to a predetermined voltage V2 (S213 in FIG. 2, T6 to T7 in FIG. 3).

  When the charging voltage of the storage element 7 reaches V2, the boost control circuit 5 stops turning on / off the switching element of the boost circuit 6 and stops charging the storage element 7 (S214 in FIG. 2, T7 in FIG. 3). ).

  The overall control unit 3 performs input confirmation of full-press of a release button (not shown) as an operation unit (S215 in FIG. 2).

  When the full-press input (SW2) of the release button is confirmed in S215 (T8 in FIG. 3), the boost control circuit 5 can turn on the output voltage set value of the boost circuit 6 for the light emitting element 2 as an AF auxiliary light application. The voltage is changed to V1 (S216 in FIG. 2 and T8 in FIG. 3).

  The light emission control circuit 4 causes a current to flow through the light emitting element 2 at a predetermined current value I2 to turn on the light emitting element 2, and the overall control unit 3 acquires image information of the camera unit 8 (S217 in FIG. 2, FIG. 3 T8-T9). The current value I2 is a current value higher than the current value I1 of about 500 mA to 2 A.

  Regarding the light emission amount control of the strobe, the current value I2 may be controlled to be variable in addition to the time when the light emitting element 2 is turned on with the current value I2 fixed as in the present embodiment.

  On the other hand, if it is determined in step S209 that the flash is not emitted at the time of shooting, the overall control unit 3 confirms the input of a fully-pressed release button (not shown) as the operation unit (S218 in FIG. 2).

  When the full-press input of the release button is confirmed in S219, the overall control unit 3 acquires image information of the camera unit 8 (S219 in FIG. 2).

  In the present invention, the charging voltage of the power storage element 7 is normally set to a low voltage at which the light emitting element 2 can be turned on as AF auxiliary light, and can be turned on as a strobe when it is determined that strobe light emission is necessary when shooting. Charge to the correct voltage. Therefore, since the period during which the high voltage (V2) is applied to the power storage element 7 is reduced, the single light emitting element can be used for AF auxiliary light and strobe without promoting the deterioration of the characteristics (capacity) of the power storage element 7. An imaging device can be provided.

  Further, when SW1 is released in the process of S210 to S215, the boost control means changes the output voltage setting value of the booster circuit 6 to V1 at that time, and performs control to discharge the charging voltage of the storage element 7 to V1. You may go. By doing so, the period during which a higher voltage is further applied to the power storage element 7 is reduced, and the characteristic (capacity) deterioration of the power storage element 7 can be reduced.

  Further, when the camera unit 8 is activated in the continuous shooting mode, S215 may be executed at the end of the flash emission continuous shooting. In this case, since the charging voltage setting value is not changed every time shooting is performed, shooting can be performed without reducing the continuous shooting speed.

DESCRIPTION OF SYMBOLS 1 ... Imaging device 2 ... Light emitting element 3 ... Whole control part 4 ... Light emission control circuit 5 ... Boosting control circuit 6 ... Boosting circuit 7 ... Power storage element 8 ... Camera Part 9 ... Battery power

Claims (4)

A power source for supplying power of a primary battery or a secondary battery;
Boosting means for boosting the voltage of the power supply;
Boost control means for controlling the boost circuit;
A storage element connected to a booster circuit and storing electric charge from a power supply;
A light-emitting element that combines the strobe for still image shooting, the AF auxiliary light, and the self-timer warning light,
A light emission control means for controlling the light emission amount of the light emitting element;
In an imaging apparatus comprising:
The step-up control means charges the storage element to a voltage at which the light emitting element can be turned on as AF auxiliary light at the time of start-up, and charges to a voltage at which strobe light emission is possible when it is determined to perform strobe light emission photography. An imaging device. 2. The imaging apparatus according to claim 1, wherein the boosting control unit changes the set value of the voltage of the boosting unit to a voltage at which the light emitting element can be turned on as AF auxiliary light immediately before the strobe flash photography. When the image pickup apparatus is set to a continuous shooting mode, the boost control means sets the voltage setting value of the boost means to the strobe even if it detects that the storage element has been charged to a voltage at which strobe light emission is possible. The imaging apparatus according to claim 2, wherein the imaging device is not changed from a voltage value at which light emission is possible. The step-up control means discharges the storage element to a voltage at which the light emitting element can be turned on as AF auxiliary light when an operation relating to flash photography is released after charging the storage element to a voltage at which strobe light emission is possible. The imaging apparatus according to claim 3.