Imaging device

Abstract

To prolong the usable time of a device.SOLUTION: An imaging device 100 includes a mechanical shutter 101, a shutter driving part 102 for operating the mechanical shutter 101 in a consecutive shot mode and in a single shot mode, a drive power supply part 103, and an undercut control part (undercut / drive power control part 105) for stopping the operation of the imaging device 100, when a power supply voltage becomes lower than a predetermined undercut voltage. In the single shot mode, the drive power supply part 103 more suppresses drive power and the undercut control part stops the operation of the imaging device 100 at a lower undercut voltage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an imaging device having an image sensor and a mechanical shutter. [Background technology]

[0002] Generally, in devices that have mechanical components that operate when powered, a technique is known that properly stops, i.e., shuts down, the system when the battery output voltage drops to a preset shutdown voltage in order to prevent the device from malfunctioning due to a drop in power supply voltage during operation (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-328701 Summary of the Invention [Problem to be solved by the invention]

[0004] Since the shutdown voltage as described above is set according to the power supply voltage that drops when mechanical components are operating, if the power supply voltage drops significantly, it becomes difficult to extend the amount of time the device can be used before being shut down.

[0005] The present invention has been made in consideration of the above-mentioned points, and has an object to provide an imaging device that can easily extend the usable time of the device. [Means for solving the problem]

[0006] In order to achieve the above objectives, The present invention relates to 1. An imaging device, comprising: a mechanical shutter disposed between the optical system and the image sensor, the mechanical shutter controlling exposure and blocking of the image sensor; a shutter driver that drives the mechanical shutter to operate the image sensor in a continuous shooting mode for continuously exposing the image sensor and in a single shooting mode for exposing the image sensor in a single shot; a driving power supply unit that supplies driving power to the shutter driving unit using power supplied from a power source; an undercut control unit that stops an operation of the imaging device when a power supply voltage supplied from the power supply becomes lower than a predetermined undercut voltage; Equipped with the driving power supply unit supplies a driving power that is suppressed in the single shooting mode compared to the continuous shooting mode, The undercut control unit stops the operation of the imaging device in the single shooting mode at an undercut voltage that is lower than that in the continuous shooting mode.

[0007] This makes it possible to suppress a drop in the power supply voltage in the single shot mode, and easily extends the usable time of the device. Effect of the Invention

[0008] The present invention makes it easy to extend the usable time of the device. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a configuration of a main part related to driving a mechanical shutter of an image pickup device; [Diagram 2] Graph showing voltage and current of each part when mechanical shutter is operating [Diagram 3] Graph showing changes in battery voltage [Figure 4] Flowchart showing the setting operation of the mechanical shutter drive voltage drop time and the undercut voltage DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Configuration of Main Parts Related to Driving the Mechanical Shutter of an Imaging Device) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0011] 1, the imaging device 100 is a digital camera, and includes a mechanical shutter 101, a shutter driving unit 102, a driving power supply unit 103, a battery 104, an undercut / driving power control unit 105, and a flash memory 106. The battery 104 may be a dry cell or a rechargeable battery.

[0012] The mechanical shutter 101 is disposed between an optical system (not shown) and an image sensor, and controls exposure and shading of the image sensor.

[0013] A shutter driver 102 drives the mechanical shutter 101 in response to a shutter control signal, and operates the image sensor in a continuous shooting mode for continuous exposure and in a single shooting mode for single exposure.

[0014] The driving power supply unit 103 supplies driving power to the shutter driving unit 102 by power supplied from a battery 104, which is a power source. More specifically, in the single shooting mode, a driving power that is suppressed is supplied compared to the continuous shooting mode. The suppression of the driving power is specifically achieved, for example, by supplying a driving current that is suppressed in the single shooting mode compared to the continuous shooting mode. More specifically, for example, the driving voltage supplied to the shutter driving unit 102 is suppressed to a predetermined value low until a predetermined time has elapsed after the mechanical shutter 101 starts operating, and the predetermined time is made longer in the single shooting mode than in the continuous shooting mode.

[0015] If the specified time is lengthened in continuous shooting mode, the number of frames that can be taken per second during high-speed continuous shooting will decrease, leading to a decline in product appeal. In single shooting mode, there is no limit to the number of frames that can be taken per second. From the above, it is possible to change the time for which the drive voltage of the mechanical shutter 101 is reduced so that it is longer than in continuous shooting mode.

[0016] The undercut / driving power control unit 105 is adapted to stop the operation of the imaging device 100 when the power supply voltage supplied from the battery 104 becomes lower than a predetermined undercut voltage. The above-mentioned predetermined undercut voltage is set, for example, in single shooting mode so as to stop the operation of the imaging device 100 at an undercut voltage lower than that in continuous shooting mode.

[0017] The flash memory 106 stores in advance the voltage to be set as the undercut voltage.

[0018] (Operation of imaging device) In the above-described imaging device 100, the mechanical shutter 101 operates in the continuous shooting mode and the single shooting mode as shown in Fig. 2. In Fig. 2, the horizontal axis represents elapsed time, and the vertical axes represent drive voltage, power supply voltage, and drive current.

[0019] (a) First, when driving of the mechanical shutter 101 is started by a control signal, a driving voltage V2 (e.g., V2: 5V) that is set a predetermined value lower than a steady driving voltage V1 (e.g., V1: 7.5V) is supplied to the shutter driving unit 102. In this case, the current (supplied current) that flows to the shutter driving unit 102 (and flows to the mechanical shutter 101 via the shutter driving unit 102) is kept smaller than when the driving voltage V1 is supplied. For example, the above current flows as a large inrush current once, and gradually decreases over time.

[0020] (b) Next, in the case of continuous shooting mode, after the time T1 (e.g., 2 ms) has elapsed, the drive voltage is increased from V2 to V1. In this case, the inrush current I1 (e.g., I1: 3.5 A) flowing through the shutter drive unit 102 as described above is kept small compared to the case where the drive voltage V1 is supplied from the beginning when driving is started.

[0021] (c) In the single shot mode, the drive voltage is increased from V2 to V1 after a time T2 (e.g., 10 ms) has elapsed. In this case, the inrush current I2 (e.g., I2: 2.5 A) caused by the supply of the drive voltage V2 is further reduced compared to the continuous shot mode, so that the increase in current is kept small even when the drive voltage is increased from V2 to V1. This also enables the protection function against overcurrent of the battery 104 to be activated.

[0022] When the increase in the current flowing through the shutter driver 102 is suppressed to a small extent as described above, the drop in the power supply voltage supplied from the battery 104 is correspondingly suppressed to a small extent. Therefore, in order to prevent the mechanical shutter 101 from operating normally if the power supply voltage drops while the mechanical shutter 101 is being driven as described above, the undercut voltage at which the image pickup device 100 stops operating is set differently in the single shooting mode and in the high-speed continuous shooting mode. Specifically, when the power supply voltage of the battery 104 under no load gradually drops over time as shown in FIG. 3, the undercut voltage can be lowered from Vuc1 (e.g., 6.5V) in the continuous shooting mode to Vuc2 (e.g., 6.1V) in the single shooting mode, for example, to maintain a high number of shots that can be taken per second in the continuous shooting mode, while increasing the operating time from TL1 to TL2, etc., in the single shooting mode, thereby increasing the number of shots that can be taken.

[0023] The times T1, T2 and the undercut voltages Vuc1, Vuc2 during which the drive voltage is suppressed to V2 as described above are not particularly limited, but are stored in advance in the flash memory 106, for example, as shown below (Table 1), and are controlled by the undercut / drive power control unit 105 based on this.

[0024] [Table 1]

[0025] Moreover, the times T1, T2 during which the drive voltage is suppressed to V2 and the undercut voltages Vuc1, Vuc2 are set, for example, as shown in FIG.

[0026] (S1) When the user selects the still image mode using an operation unit (not shown), a control unit (controller) (not shown) first determines whether the mode is the single shot mode.

[0027] (S2, S3) If the controller determines that the mode is the single shot mode, it sets the mechanical shutter drive voltage drop time to T2 in undercut / drive power control unit 105, and sets the undercut voltage to Vuc2.

[0028] (S4, S5) On the other hand, if the controller determines in (S1) above that the continuous shooting mode is selected, it sets the mechanical shutter drive voltage drop time to T1 in undercut / drive power control section 105, and sets the undercut voltage to Vuc1.

[0029] Based on these set values, the above-mentioned control is performed.

[0030] (Other matters) In addition to the above configuration, a remaining capacity detection unit may be provided that detects the remaining capacity of the battery 104, and the time for which the driving voltage is suppressed to V2 by the driving power supply unit 103 may be set based on the detected remaining capacity. Specifically, for example, when there is a margin of remaining capacity, the time for which the driving voltage is reduced may be shortened, and the shooting frame rate may be increased.

[0031] In the above embodiment, the imaging device is a digital camera, but the imaging device is not limited to this. The imaging device of the present disclosure may be any electronic device having an image capturing function (e.g., a video camera, a smartphone, a tablet terminal, etc.). [Explanation of symbols]

[0032] 100 Imaging device 101 Mechanical Shutter 102 Shutter drive unit 103 Drive power supply unit 104 Batteries 105 Undercut / Drive power control section 106 Flash Memory

Claims

1. 1. An imaging device, comprising: a mechanical shutter disposed between the optical system and the image sensor, the mechanical shutter controlling exposure and blocking of the image sensor; a shutter driver that drives the mechanical shutter to operate the image sensor in a continuous shooting mode for continuously exposing the image sensor and in a single shooting mode for exposing the image sensor in a single shot; a driving power supply unit that supplies driving power to the shutter driving unit using power supplied from a power source; an undercut control unit that stops an operation of the imaging device when a power supply voltage supplied from the power supply becomes lower than a predetermined undercut voltage; Equipped with the driving power supply unit supplies a driving power that is suppressed in the single shooting mode compared to the continuous shooting mode, The imaging device, wherein the undercut control unit stops operation of the imaging device in the single shooting mode at an undercut voltage that is lower than that in the continuous shooting mode.

2. 2. The imaging device of claim 1, 2. An imaging apparatus according to claim 1, wherein the driving power supply unit is configured to supply a driving current that is suppressed in the single shooting mode compared to the continuous shooting mode.

3. 3. The imaging device of claim 2, the drive power supply unit is configured to keep the drive voltage supplied to the shutter drive unit low by a predetermined amount for a predetermined time after the mechanical shutter starts to operate, and to make the predetermined time longer in the single shooting mode than in the continuous shooting mode.

4. 4. The imaging device of claim 3, the power source is a battery; Further, a remaining capacity detection unit is provided for detecting a remaining capacity of the battery, 4. The imaging device according to claim 3, wherein the driving power supply unit is further configured to set the predetermined time based on the remaining capacity.

5. an imaging sensor that captures an object image via an optical system and generates image data; a mechanical shutter disposed between the optical system and the image sensor, the mechanical shutter controlling exposure and blocking of the image sensor; a shutter driver that drives the mechanical shutter to operate the image sensor in a continuous shooting mode for continuously exposing the image sensor and in a single shooting mode for exposing the image sensor in a single shot; a driving power supply unit that supplies driving power to the shutter driving unit using power supplied from a power source; Equipped with the drive power supply unit is configured to keep the drive voltage supplied to the shutter drive unit low by a predetermined amount for a predetermined time after the mechanical shutter starts to operate, and to make the predetermined time longer in the single shooting mode than in the continuous shooting mode.

Images