JP4020704B2 - Power supply and camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes, for example, a power supply device for individually applying output voltages having different values to a plurality of electrodes, and a deformable mirror having a reflecting surface whose shape changes depending on the output voltages applied to the plurality of electrodes, respectively. In particular, the present invention relates to a power supply device and a camera that realizes a reduction in circuit scale and good controllability.
[0002]
[Prior art]
In recent years, a subject image is imaged on a semiconductor image sensor such as a CCD two-dimensional image sensor by an imaging optical system and converted into an electrical signal, and the image data of the subject image thus obtained is recorded on a semiconductor memory or a magnetic disk. So-called electronic cameras that record on a medium are becoming widespread.
[0003]
In addition, this type of electronic camera has a lens for forming a subject image on a semiconductor image sensor, and many of them are glass lenses whose refractive index and shape are difficult to change due to changes in temperature and humidity. It has been adopted. On the other hand, recently, demands for weight reduction and cost reduction have increased, and it has been considered to adopt a plastic lens instead of a glass lens. However, since the plastic lens tends to deteriorate the imaging performance due to a change in temperature and humidity, when adopting this, it is necessary to take some measures against the change in temperature and humidity.
[0004]
For this reason, the applicant of the present application has an optical reflecting surface as described in Japanese Patent Application No. 11-72557 (Japanese Patent Application Laid-Open No. 2000-267010), for example, and the shape of the reflecting surface is electrically changed by electrostatic force. Has led to the proposal of a deformable mirror element that can be controlled automatically. By using this deformable mirror element, for example, it is possible to compensate for changes in optical characteristics due to changes in temperature and humidity of a plastic lens, for example, by changing the shape of the reflecting surface. It becomes possible to answer.
[0005]
[Problems to be solved by the invention]
By the way, in order to control the shape of the reflecting surface of the deformable mirror, that is, to control the shape to obtain a desired optical characteristic, it is necessary to apply various voltages to a plurality of electrodes of the deformable mirror. In particular, when a large displacement is desired, a voltage of several tens of volts must be applied. If a power supply circuit capable of supplying such a voltage is provided for each electrode, the scale of the drive circuit increases, leading to an increase in cost, an increase in mounting area, and an increase in power consumption. There was also a risk that it could not be applied to the camera.
[0006]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a power supply device and a camera that realize a reduction in circuit scale and good controllability. .
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, the power supply device of the present invention has a plurality of input units, and is capable of forming an image that can change optical characteristics by electrically controlling each input unit. A power supply device for controlling a mirror element to be used , which is connected to a power supply circuit that generates an output voltage that continuously changes monotonously, and an output of the power supply circuit and any one of a plurality of input portions of the mirror element. A plurality of switches for connecting or disconnecting between the plurality of input portions of the mirror element and the output of the power supply circuit, and information indicating a correspondence relationship between the output voltage of the power supply circuit and the drive timing of the switch a storage unit for previously storing for each optical properties of the mirror element, based on the previously stored optical characteristic for each of the information of the mirror element in the storage unit, the mirror by driving and controlling the plurality of switches A voltage is supplied to each of a plurality of input portions of the element, and the same voltage is simultaneously applied to two or more input portions that require the same voltage among the plurality of input portions of the mirror element. And a drive control unit that variably controls the optical characteristics of the mirror element so as to be supplied .
[0008]
In this power supply device, since the continuously and monotonically changing output voltage generated from one power supply circuit can be individually applied to a plurality of electrodes at the time when each becomes a required value, the circuit scale It is possible to reduce the size and to provide good controllability.
[0009]
The camera of this invention, said power supply device, so as to include a step-up power source circuit for a flash to illuminate a subject, the power supply circuit of the power supply, to share the circuit of the booster power supply circuit and a portion It is characterized by being configured .
[0010]
In this camera, various voltages to be applied to the plurality of electrodes of the deformable mirror are covered by the output voltage of one power supply circuit, and a part of the power supply circuit is shared with the boost power supply circuit for flash. Therefore, it is possible to appropriately reduce the circuit scale and improve the controllability, which are the intended purposes.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
(First embodiment)
First, a first embodiment of the present invention will be described.
[0013]
FIG. 1 is a diagram showing the configuration of an electronic camera according to the first embodiment of the present invention.
[0014]
The subject light from the subject passes through the optical system 1 composed of a plurality of lenses, and is reflected by an optical element having a deformable mirror, which will be described later, that is, a reflection surface of the variable mirror 2, and then the amount of light is controlled by the diaphragm 3. The The subject light that has passed through the diaphragm 3 is incident on the image sensor 4 and forms a subject image on the photographing surface.
[0015]
The imaging device 4 forms an imaging surface in which a plurality of pixels that perform photoelectric conversion are arranged in a two-dimensional matrix, and a color filter is disposed on the imaging surface to correspond to the subject image formed on the imaging surface. Accumulated signal charge. An image pickup circuit 5 is connected to the image pickup element 4, and exposure, reading, element shutter, gain adjustment, power supply, and the like are controlled by the image pickup circuit 5. The output from the image sensor 4 is converted into a digital signal by the A / D converter 6 and then guided to the image processing unit 7 where ISO sensitivity setting, auto white balance, luminance / color signal generation, gamma processing, and the like are performed. As a result, a color image signal of a predetermined format is generated.
[0016]
The color image signal generated by the image processing unit 7 is temporarily stored in a buffer memory 8 composed of, for example, a DRAM. The image signal stored in the buffer memory 8 is transferred to the video memory 9 and then displayed on the image display LCD 11 via the video output circuit 10. The image signal stored in the buffer memory 8 is read out by the interface unit 12 and subjected to, for example, JPEG compression encoding processing, and is recorded in a removable memory 14 that is detachably stored in the card slot 13. The
[0017]
The overall control related to the electronic camera including the above-described driving of each part is governed by the system controller 15, and the system controller 15 drives and controls the variable mirror 2 via the mirror control unit 16. The mirror control unit 16 freely drives the variable mirror 2 by taking out and supplying power of various voltage values from the output of the mirror power supply unit 17. The electronic camera according to the first embodiment is characterized in that the power supply control for the variable mirror 2 is efficiently executed by the mirror control unit 16 and the mirror power supply unit 17, which will be described later. .
[0018]
The system controller 15 is connected to a strobe light emitting unit 18 that is a light source for illuminating the subject. The strobe light emitting unit 18 includes a capacitor capable of storing a predetermined amount of charge, and the system controller 15 controls driving of the strobe light emitting unit 18 by charging and discharging the capacitor.
[0019]
The operation unit 19 generates command signals for performing various operations based on operations by the user and transmits them to the system controller 15. The camera power supply unit 20 supplies power for operation to each unit in the electronic camera. The EEPROM 21 stores various basic information such as environment setting information that is referred to when the system controller 15 controls the operation of the electronic camera.
[0020]
Here, with reference to FIG. 2 and FIG. 3, the structure of the variable mirror 2 mentioned above is explained in full detail. FIG. 2 is a diagram showing assignment of a plurality of electrodes provided to control the shape of the reflecting surface of the variable mirror 2 on the reflecting surface, and FIG. 3 is a diagram showing a structure of the variable mirror 2 including the plurality of electrodes. It is.
[0021]
As shown in FIGS. 2 and 3, the variable mirror 2 has, for example, a reflective surface 31 that is aluminum-coated on a polyimide thin film, and nine electrodes A to I. The plurality of electrodes When a voltage is applied to the thin film, the thin film is deformed by electrostatic force, and the shape of the reflecting surface changes. Then, by controlling the magnitude of the voltage applied to the nine electrodes, the shape of the reflecting surface can be freely formed. Even if the electrode is opened after the voltage is applied to the electrode, the voltage is maintained for a predetermined time.
[0022]
By the way, since recent electronic cameras tend to be small and light, it is realistic to provide a power supply circuit for each electrode to apply a desired voltage to the nine electrodes A to I. is not. Therefore, in the electronic camera of the first embodiment, the mirror power supply unit 17 generates an output voltage that continuously and monotonously changes, and the mirror control unit 16 performs this mirror at the timing when each electrode has a required value. The power generated by the power supply unit 17 is controlled to be supplied to each of the plurality of electrodes. Hereinafter, the power supply method by the mirror control unit 16 and the mirror power supply unit 17 will be described in detail.
[0023]
FIG. 4 is a conceptual diagram for explaining an operation principle of power supply control for the variable mirror 2 executed by the electronic camera of the first embodiment.
[0024]
Here, in order to simplify the description, it is assumed that the shape of the reflecting surface of the variable mirror 2 is controlled by three electrodes A to C. Then, the mirror control unit 16 for controlling the shape of the reflecting surface connects / disconnects between each electrode of the variable mirror 2 and the mirror power supply unit 17, that is, applies a voltage to each electrode or opens each electrode. In response to an instruction from the mirror controller 16, the mirror power supply unit 17 generates an output voltage that changes continuously and monotonously only once. It has a one-shot power supply function. Here, the switches A to C may be constituted by, for example, a pnp type bipolar transistor for power supply control, a p channel type power MOS transistor, or the like.
[0025]
When controlling the shape of the reflecting surface of the variable mirror 2, the mirror control unit 16 first instructs the mirror power supply unit 17 to generate an output voltage that continuously changes monotonously (one-shot trigger). At the same time, the mirror controller 16 drives the switches A to C to the connected state.
[0026]
On the other hand, upon receiving this instruction, the mirror power supply unit 17 generates the output voltage that changes continuously and monotonously only once. Then, when this output voltage reaches a value required by any of the electrodes, the mirror control unit 16 drives and controls the switches A to C so as to disconnect between the electrode and the mirror power supply unit 17. . The one-shot trigger input to the mirror power supply unit 17 and the drive control of the switches A to C are executed by a timing control unit 16a provided in the mirror control unit 16.
[0027]
The system controller 15 instructs the drive timing of the switches A to C by the timing control unit 16a. The system controller 15 stores information for obtaining this timing in the EEPROM 21. This information is held as follows in the form of a table in which, for example, the amount of displacement of the reflecting mirror shape of the variable mirror 2 is associated with the time during which the switches A to C are kept connected.
[0028]
Displacement (P0): Switch A (0 ms), B (0 ms), C (0 ms)
Displacement (P1): Switch A (5 ms), B (10 ms), C (30 ms)
Displacement (P2): Switch A (20 ms), B (70 ms), C (80 ms)
That is, for example, when the displacement amount of the reflecting surface shape of the variable mirror 2 is P1, the system controller 15 disconnects the switch A after 5 ms after setting the switches A to C together with the one-shot trigger input. In addition, the control unit 16a is instructed to disconnect the switch B after 10 ms and further disconnect the switch C after 30 ms.
[0029]
FIG. 5 is a timing chart showing an example of an operation procedure of power supply control for the variable mirror 2 executed by the electronic camera of the first embodiment.
[0030]
First, the mirror control unit 16 gives a one-shot trigger to the mirror power supply unit 17 and drives the switches A to C to a connected state. On the other hand, the mirror power supply unit 17 given the one-shot trigger starts generating an output voltage that continuously changes monotonously.
[0031]
Thereafter, the mirror control unit 16 drives the switch A to the disconnected state at the timing a, drives the switch C to the disconnected state at the timing c, and further drives the switch B to the disconnected state at the timing b. To do.
[0032]
As a result, the voltage Va is applied to the electrode A, the voltage Vb is applied to the electrode B, and the voltage Vc is applied to the electrode C, and only the mirror power supply unit 17 that is a single power supply circuit is provided. The purpose of the period can be achieved. That is, a power supply method that achieves reduction in circuit scale and good controllability is realized.
[0033]
Here, an example in which the drive timing of the switches A to C is obtained from the information stored in the EEPROM 21 has been described, but instead, for example, a circuit for detecting the output voltage of the mirror power supply unit 17 is provided. Based on the detection result, the drive timing of the switches A to C may be obtained.
[0034]
With such a configuration, it is possible to apply an appropriate voltage according to the output voltage to each electrode.
[0035]
(Second Embodiment)
Next explained is the second embodiment of the invention.
[0036]
FIG. 6 is a conceptual diagram for explaining the operating principle of power supply control for the variable mirror 2 executed by the electronic camera of the second embodiment.
[0037]
The difference between the second embodiment and the first embodiment described above is that the mirror power supply unit 17 has a triangular wave power supply function that repeatedly generates an output voltage that continuously changes monotonously instead of the one-shot power supply function. In the point. Further, every time the generation of the output voltage is started, the mirror power supply unit 17 notifies the start timing to the mirror control unit 16 (trigger).
[0038]
On the other hand, when controlling the shape of the reflecting surface of the variable mirror 2, the mirror control unit 16 drives and controls the switches A to C in synchronization with the trigger input from the mirror power supply unit 17.
[0039]
FIG. 7 is a timing chart showing an example of an operation procedure of power supply control for the variable mirror 2 executed in the electronic camera of the second embodiment.
[0040]
The mirror power supply unit 17 repeatedly generates an output voltage that continuously changes monotonously and continues to give a trigger for notifying the start timing to the mirror control unit 16. On the other hand, the mirror controller 16 first drives the switch A to the connected state when a certain trigger is input, and then drives the switch A to the disconnected state at the timing a. Further, the mirror control unit 16 drives the switch B to the disconnected state at the timing b after driving the switch B to the connected state at the time of the next trigger input. Further, after driving the switch C to the connected state at the next trigger input, the mirror control unit 16 drives the switch C to the disconnected state at the timing c.
[0041]
As a result, the voltage Va is applied to the electrode A, the voltage Vb is applied to the electrode B, and the voltage Vc is applied to the electrode C. As in the first embodiment, the mirror power supply unit 17 which is a single power supply circuit. It is possible to achieve the intended purpose only by providing. That is, a power supply method that achieves reduction in circuit scale and good controllability is realized.
[0042]
Here, the example in which the voltages Va to Vc applied to the electrodes A to C are obtained based on the output voltages generated at different timings by the mirror power supply unit 17 has been described. When the same voltage is required, it is desirable to acquire them at the same timing. Further, even when different voltages are required, it is naturally possible to acquire all at the same timing by the same procedure as that described in the first embodiment.
[0043]
With such a configuration, an appropriate voltage corresponding to the output voltage can be applied to each electrode as in the first embodiment.
[0044]
(Third embodiment)
Next explained is the third embodiment of the invention.
[0045]
The electronic camera according to the third embodiment is an improvement of the electronic camera according to the first or second embodiment, and the mirror power supply unit 17 is configured to share a part of the strobe light emitting unit 18. Features. FIG. 8 is a diagram showing the configuration of the mirror power supply unit 17 and the strobe light emitting unit 18 in the electronic camera of the third embodiment.
[0046]
The strobe light emitting unit 18 includes a large-capacity capacitor for causing the xenon tube to emit light, and a high voltage such as 330 V is required to charge the large-capacity capacitor. Therefore, the strobe light emitting unit 18 is provided with a boost power supply circuit for boosting the output voltage of the flash power supply that is much lower than this. The boost power supply circuit continues to boost the output voltage of the flash power supply while receiving the flash charge pulse. That is, if the flash charge pulse is continuously generated, an output voltage that continuously changes monotonously can be generated. If the output voltage generated in this way is used, a desired voltage can be applied to the electrodes A to C as described in the first and second embodiments.
[0047]
As described above, in the electronic camera according to the third embodiment, the mirror power supply unit 17 is configured so as to share a part of the strobe light emitting unit 18, thereby further reducing the circuit scale.
[0048]
According to each of the above embodiments, if the output voltage continuously changing monotonously is generated only once each time it is necessary to apply a voltage of some value to the electrode, the output voltage can be further improved. Power saving can be achieved, and on the other hand, if it is repeatedly generated at a predetermined cycle, it is possible to accurately cope with a situation where the voltage applied to each electrode must be changed frequently.
[0049]
In addition, the drive timing of the switch for extracting a voltage of an arbitrary value from the output voltage that changes monotonously continuously is stored in the memory, and the switch is driven using the data stored in the memory. For example, it is not necessary to perform complicated calculations, so it can be applied to low-priced products. On the other hand, if a sensor is provided, it is possible to take out an extremely accurate voltage that is completely unaffected by the operating conditions at that time. Is possible.
[0050]
Further, when the same voltage value is required for a plurality of electrodes, if the output voltage is simultaneously applied to these electrodes, the drive control of the switch can be executed efficiently.
[0051]
Furthermore, if this power supply device is applied to a camera equipped with a deformable mirror, various values of voltage applied to a plurality of electrodes provided to change the shape of the reflecting surface of the deformable mirror are supplied to the power supply. Since it can be supplied by a single device, it does not increase costs, increase the mounting area, or increase power consumption, and is configured to share part of the boost power supply circuit for the flash that illuminates the subject. In this way, it is possible to reduce costs and reduce the size by reducing the number of parts.
[0052]
Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be obtained as an invention.
[0053]
【The invention's effect】
As described above in detail, according to the present invention, a continuously monotonically changing output voltage generated from one power supply circuit is individually applied to a plurality of electrodes at a timing when each becomes a required value. Therefore, the circuit scale can be reduced and the controllability can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an electronic camera according to a first embodiment of the invention.
FIG. 2 is a view showing allocation on a reflecting surface of a plurality of electrodes provided for controlling the reflecting surface shape of a variable mirror included in the electronic camera of the first embodiment;
FIG. 3 is a view showing a structure of a variable mirror including a plurality of electrodes provided in the electronic camera of the first embodiment.
FIG. 4 is a conceptual diagram for explaining an operation principle of power supply control for a variable mirror executed by the electronic camera of the first embodiment.
FIG. 5 is a timing chart showing an example of an operation procedure of power supply control for the variable mirror executed by the electronic camera of the first embodiment.
FIG. 6 is a conceptual diagram for explaining an operation principle of power supply control for a variable mirror executed by the electronic camera of the second embodiment.
FIG. 7 is a timing chart showing an example of an operation procedure of power supply control for the variable mirror 2 executed by the electronic camera of the second embodiment.
FIG. 8 is a diagram showing a configuration of a mirror power supply unit and a strobe light emitting unit in the electronic camera of the third embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical system 2 ... Variable mirror 3 ... Diaphragm 4 ... Imaging device 5 ... Imaging circuit 6 ... A / D converter 7 ... Image processing part 8 ... Buffer memory 9 ... Video memory 10 ... Video output circuit 11 ... Image display LCD
DESCRIPTION OF SYMBOLS 12 ... Interface part 13 ... Card slot 14 ... Detachable memory 15 ... System controller 16 ... Mirror control part 16a ... Timing control part 17 ... Mirror power supply part 18 ... Strobe light emission part 19 ... Operation part 20 ... Camera power supply part 21 ... EEPROM
31 ... reflecting surface

Claims (5)

A power supply device that controls a mirror element used for image formation , having a plurality of input units, and capable of changing optical characteristics by electrically controlling each input unit,
A power supply circuit that generates an output voltage that continuously changes monotonously;
Connected to said output of the power supply circuit and one of a plurality of input portions of the mirror element, the plurality of switches to connect or disconnect between the plurality of inputs of the connected the mirror element and the output of the power supply circuit When,
A storage unit that stores in advance information indicating the correspondence between the output voltage of the power supply circuit and the drive timing of the switch for each optical characteristic of the mirror element;
Based on information for each optical characteristic of the mirror element stored in advance in the storage unit, a voltage is supplied to each of the plurality of input units of the mirror element by driving and controlling the plurality of switches , A drive control unit that variably controls the optical characteristics of the mirror element so as to simultaneously supply the same voltage to two or more input units that require the same voltage among a plurality of input units of the mirror element ; A power supply device comprising: The drive control unit has means for instructing the power supply circuit to execute the output accompanied by the predetermined voltage change,
2. The power supply apparatus according to claim 1, wherein the power supply circuit performs the output accompanied by the predetermined voltage change once each time an instruction from the drive control unit is received.   The power supply apparatus according to claim 1, wherein the power supply circuit repeatedly performs output with a predetermined voltage change at a predetermined cycle, and notifies the drive control unit of the start timing for each cycle. Comprising a detector for detecting an output voltage value of the power supply circuit;
The power supply device according to claim 1, wherein the drive control unit drives and controls the plurality of switches based on a detection result of the detection unit. The power supply device according to claim 1,
A step-up power supply circuit for a flash that illuminates the subject, and
The power supply circuit of the power supply device is configured to share a part of the circuit with the boost power supply circuit.

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