JP2003037771A - Electronic camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the operation available time of an electronic camera employing a battery for a power supply. SOLUTION: While a CPU-A1 controls an actuator drive circuit 21 according to the 1st release to operate an actuator 20 for focusing operation or while the CPU-A1 controls the actuator drive circuit 21 according to the 2nd release to operate the actuator 20 for operating a shutter, the CPU-A1 controls a display section comprising a TFT(thin film transistor) liquid crystal drive circuit 17, a TFT panel 18 and a backlight unit 19 to reduce the power applied to the display section, so as to utilize the electrical energy stored in the battery 26 used for the power supply of the electronic camera less wastefully than that of a conventional electronic camera.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique used in an electronic camera, and more particularly to a technique used in an electronic camera using a battery as a power source.

[0002]

2. Description of the Related Art An invention relating to a technique for extending the usable time of an electronic camera using a battery as a power source is disclosed in Japanese Patent Application Laid-Open No. HEI-1
It is disclosed in JP-A-341322. According to the present invention, in a digital camera, when a captured image is recorded on an IC card, the power supplied to a backlight for an LCD (Liquid Crystal Display) is reduced to save power consumption and prolong its usable time. Is.

[0003]

It is a common general knowledge that when a current is taken out from a battery, a voltage drop occurs due to the internal resistance of the battery itself, and the larger the taken current is, the larger the voltage drop amount is.

In a general electronic camera, the voltage of a battery used as a power source is monitored, and if the voltage becomes smaller than a predetermined value even for a short time, there is a possibility that a photographing operation may be defective. After that, the photographing operation after that is prohibited, and the user is notified by a display or the like that the battery level is low. Therefore, of the components provided in the electronic camera, when a component that is temporarily operated only when necessary is operated simultaneously with a component that is always operated, the battery voltage falls below a predetermined value due to the voltage drop described above. After that, the electronic camera is prohibited from use. However, when I looked into the battery when it was banned, there was still a considerable amount of electrical energy left, and the remaining electrical energy could not be used to operate the electronic camera. The usable time of the electronic camera was shortened.

In recent years, I which records digital data
As a result of the improvements made to the C card, the amount of power consumed by the IC card for data recording processing has been significantly reduced. Therefore, the amount of battery voltage drop caused by recording captured images on the IC card is greater than before. Is much less, I
The use of the C card has less influence on the usable time of the electronic camera.

In view of the above circumstances, it is a problem to be solved by the present invention to extend the usable time of an electronic camera using a battery as a power source.

[0007]

An electronic camera according to one aspect of the present invention includes a display unit for displaying an image and an automatic focusing unit for automatically focusing a subject image represented in a picked-up image. The above-mentioned problems can be solved by configuring the automatic focusing means to have a control means for controlling the power applied to the display means while the automatic focusing means is performing the focusing operation.

Here, the control means may be configured to perform control for reducing the electric power by changing the display brightness of the display means. In the present specification, "changing the display brightness of the display means" means that when the display means does not emit light, such as a liquid crystal display, the display means is illuminated from the front, the back, or the inside. Means to change the brightness of the light, and when the display means is a self-luminous display monitor such as an LED display or an organic EL display, the display brightness of the display means itself is changed. It means that.

Since considerable power is consumed when the automatic focusing means performs the focusing operation, a large voltage drop occurs in the battery used as the power source of the electronic camera. However, by having the above-described configuration according to the present invention, the electric power applied to the display unit is reduced while the automatic focusing unit is performing the focusing operation, so that the voltage drop amount generated by the display unit is Reduce. As a result, the battery voltage will not drop below the specified value due to the focusing operation for a while, so the electric energy stored in the battery can be used more efficiently than before, and the usable time of the electronic camera can be reduced. Becomes longer.

An electronic camera according to another aspect of the present invention is a display means for displaying an image, a shutter drive means for driving a shutter according to a release operation, and the shutter drive means for driving the shutter. The above-mentioned problems can be solved by configuring the control means for controlling to reduce the electric power applied to the display means during the operation.

Here, the control means may be configured to perform control for reducing the electric power by changing the display brightness of the display means, or by stopping the operation of the display means. You may comprise so that the control which reduces the said electric power may be performed.

Since a considerable amount of power is consumed when the shutter driving means performs the driving operation of the shutter, a large voltage drop occurs in the battery used as the power source of the electronic camera. However, by having the above-described configuration according to the present invention, the electric power applied to the display means is reduced while the shutter drive means is performing the drive operation of the shutter, so the voltage drop amount generated by the display means is reduced. Reduce. As a result, the battery voltage will not drop below the specified value due to the shutter drive operation for a while, so the electric energy stored in the battery can be used more efficiently than before, and the usable time of the electronic camera can be reduced. Becomes longer.

An electronic camera according to still another aspect of the present invention includes a display unit for displaying an image, and an automatic focusing unit for automatically focusing a subject image shown in a picked-up image. Applied to the display means while the shutter drive means for driving the shutter in response to the release operation and the automatic focusing means perform the focusing operation, and while the shutter drive means drives the shutter. The above-mentioned problems can be solved by configuring the control means for controlling the electric power to be reduced.

Here, the control means may be configured to perform control for reducing the electric power by changing the display brightness of the display means. Even with the above-described configuration, the same operation as the above-described configuration allows the electric energy stored in the battery used as the power source of the electronic camera to be used more efficiently than before, and the electronic camera can be used. Time will increase.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an electronic camera embodying the present invention. First, the figure will be described.

CPU (Central Processing Unit) -A
A central processing unit 1 controls the operation of the entire electronic camera. EEPROM (Electrically Erasable and
The Programmable Read Only Memory) 2 stores in advance a control program for causing the CPU-A1 to control the operation of the electronic camera. The CPU-A1 executes the control program to perform the above-mentioned operation control. become.

The lens 3 is a photographing optical system for forming a subject image on the CCD 4. CCD (Charge Coupled Device
) 4 is an image sensor that photoelectrically converts the formed subject image and outputs an electric signal (analog signal) indicating the image.
The image pickup circuit 5 is a CDS (Correlated Double Sampling:
Correlated double sampling circuit) and AGC (Automatic Gain)
Control: Auto gain control circuit) and the like, and under the control of the CPU-A1, removes reset noise that may be included in the electric signal (analog signal) output from the CCD 4 and adjusts the signal level. Circuit.

The A / D converter 6 is a circuit for converting the output signal (analog signal) of the image pickup circuit 5 into digital data. The correction circuit 7 is a circuit that performs correction processing such as white balance and γ correction on a captured image represented by digital data output from the A / D conversion unit 6.

The output of the correction circuit 7 is the frame memory 8,
CPU-B9, FIFO memory 10, and recording medium I /
It is connected to F11 via a bus 12, and data can be exchanged between them under the control of the bus 12 by the CPU-B 9.

The frame memory 8 is used as a buffer memory for temporarily storing a photographed image output from the correction circuit 7 and a photographed image subjected to image processing by the CPU-B9, and various processes by the CPU-B9. Is a memory that is also used as a work storage area for.

Under the control of the CPU-A1, the CPU-B9 manages the frame memory 8 (frame memory control function) and decompresses the compressed image data according to the control program provided inside the CPU-B9. The image decompression function), the data compression processing for the captured image (image compression function), and the access control processing (recording medium access function) for accessing the recording medium 21 for writing and reading data. It should be noted that, for example, JPEG (Joint Photographic Exp
erts group) compression processing and decompression processing are performed.

FIFO (First-In-First-Out) memory 1
Reference numeral 0 denotes a memory for temporarily storing image data expressing an image to be displayed, and stores image data after being subjected to image processing by the CPU-B9. Recording medium I / F
Reference numeral 11 provides an interface function for exchanging data with the recording medium 13, and processing of writing data to the recording medium 13 or reading data from the recording medium 13 is performed.

The recording medium 13 holds recorded data, and a removable recording medium such as a memory card having a built-in semiconductor memory is convenient for an electronic camera. The video encoding circuit 14 is a CPU-A.
Under the control of No. 1, it is a circuit for superimposing on-screen information such as a date on an image represented by the data read from the FIFO memory 10.

The video output circuit 15 is a circuit for converting the digital image data output from the video encoding circuit 14 into a video signal (image signal) which is an analog signal. The video output terminal 16 is a terminal for outputting the video signal output from the video output circuit 15 to the outside of the electronic camera.

The TFT (Thin Film Transistor) liquid crystal drive circuit 17 is a TFT based on the image signal output from the video encoding circuit 14 under the control of the CPU-A1.
This is a circuit that drives the panel 18. TFT panel (TF
The T liquid crystal panel) 18 is used as a liquid crystal monitor that is driven by the TFT liquid crystal drive circuit 17 and displays an image represented by an image signal output from the video encoding circuit 14.

Since this electronic camera is equipped with an optical finder (not shown), it is possible to photograph a subject image without displaying the subject image formed on the CCD 4 on the liquid crystal monitor. The user can set whether to operate the liquid crystal monitor in this electronic camera. If the liquid crystal monitor is set so as not to operate, the power consumption of the electronic camera during normal operation can be reduced.

The backlight unit 19 is integrated with the TFT panel 18 to form a liquid crystal monitor.
The unit is provided with a light source for illuminating the liquid crystal portion of the TFT panel 18 from its rear surface under the control of the CPU-A1. As this light source, for example, a white LED (Light Emit)
ting Diode) or the like is used.

The actuator 20 is an operating device such as a motor (AF motor, zooming motor, etc.) for driving the lens (shooting optical system) 3, a mechanical shutter drive device, etc., and the actuator drive circuit 21.
Driven by. The actuator drive circuit 21 is a CPU
-A circuit that drives the actuator 20 under the control of A1.

The external data I / F 22 provides an interface function for exchanging data between an external device such as a personal computer and the CPU-A1, and is of a USB (Universal Serial Bus) system, for example. I / F. The key matrix unit 23 is a matrix of various keys, switches, buttons, etc. for receiving various instructions from the user and notifying them to the CPU-A1. A release button operated to cause the electronic camera to perform an image capturing operation is also included in the key matrix unit 23, and the CPU-A1
It is possible to detect the operation of the 1st release (so-called half press) and the 2nd release (so-called full press) of the release button.

The LCD display circuit 24 is a circuit for driving the LCD panel 25 under the control of the CPU-A1. LC
The D panel 25 is driven by the LCD display circuit 24,
Display according to the drive signal, for example, display of various setting states of the electronic camera such as exposure and shutter speed, and display of the number of images that can be captured and recorded at present are performed.

The battery 26 is a power source for supplying electric power to this electronic camera. The power supply circuit 27 is a circuit that controls the voltage supplied from the battery 26 and supplies power to each unit of the electronic camera. The CPU-A1 monitors the voltage of the battery 26 that supplies power to the power supply circuit 27, and the voltage value is temporarily changed when the electronic camera is operating normally (when the power is on). However, if it becomes smaller than the predetermined value, the CPU-A1 thereafter prohibits the photographing operation of this electronic camera, and does not perform the control processing for photographing even if the release button is operated.

Next, in the electronic camera having the above-described structure, of the control processing for the electronic camera performed by the CPU-A1, the processing contents of the photographing processing relating to the present invention will be described. FIG. 2 is a flowchart showing the processing contents of the photographing processing performed by the CPU-A1 in response to the pressing of the release button described above. In the same figure, (a) shows the processing contents of the distance measurement operation (automatic focusing operation) processing which is started when the operation of the 1st release to the release button is detected, and (b) shows the second release to the release button. The processing content of the shooting operation processing started when the operation of is detected is shown. All of these processes are realized by the control program stored in the EEPROM 2 being read and executed by the CPU-A1.

First, the flow chart of FIG. 2A will be described. When the 1st release to the release button is detected, in S101, the CPU-A1 determines the current setting state of the operation of the liquid crystal monitor (TFT panel 18 and backlight unit 19) described above. As a result, if the setting for operating the liquid crystal monitor is made (Yes in the determination result of S101), S
If the process proceeds to 103 and the liquid crystal monitor is set not to operate (the determination result in S101 is No), S1
The process proceeds to 02.

In S102, the CPU-A1 executes the AF process,
That is, information indicating the degree of contrast of the subject image currently formed on the CCD 4 is acquired from the CPU-B 9, and the actuator drive circuit 21 is instructed based on this information to operate the AF motor in the actuator 20. A process of moving the lens 3 to a position where the contrast of the subject image is the highest is performed. After this processing is completed, the processing based on this 1st release is completed.

On the other hand, if the determination result of the determination processing of S101 is Yes, the CPU-
A1 controls the backlight unit 19 to reduce the brightness of the liquid crystal monitor. If an LED is used as a light source for illuminating the liquid crystal monitor in the backlight unit 19, the brightness of the liquid crystal monitor is controlled by controlling the amount of current flowing through the LED to reduce the amount of power applied to the LED. Can be reduced.

In S104, the CPU-A1 executes the above-mentioned S.
AF processing similar to that of 102 is performed. After the end of this AF process, in S105, the CPU-A1
A process of restoring the brightness of the liquid crystal monitor reduced in the process of 03 is performed. After this processing is completed, the processing based on this 1st release is completed.

By the above control processing by the CPU-A1, the power consumption by the liquid crystal monitor is reduced during the AF operation (automatic focusing operation) started in response to the 1st release of the release button. The amount of descent is reduced. As a result, the battery voltage will not drop below the specified value due to this AF operation for a while, so the electric energy stored in the battery can be used more efficiently than before, and the usable time of the electronic camera can be reduced. Will become longer.

Next, the flowchart of FIG. 2B will be described. When the second release to the release button is detected, the CPU-A1 determines the current setting state of the operation of the liquid crystal monitor (TFT panel 18 and backlight unit 19) described above in S201. Then, as a result, if the setting for operating the liquid crystal monitor has been made (the determination result of S201 is Yes), S
If the process proceeds to 204 and the liquid crystal monitor is set not to operate (the determination result of S201 is No), S2.
The process proceeds to 02.

In S202, the CPU-A1 performs a shutter operation process, that is, a process of giving an instruction to the actuator drive circuit 21 to open / close the shutter of the actuator 20. Then, in subsequent S203, the CPU-A1 performs a CCD read operation process, that is, a process of causing the image pickup circuit 5 to read an image signal indicating a subject image formed on the CCD 4 when the shutter is opened. After that, the process proceeds to S208.

On the other hand, if the determination result of the determination processing of S201 is Yes, the CPU-
A1 stops the operation of the liquid crystal monitor by stopping the power supply from the power supply circuit 27 to the liquid crystal monitor and the TFT liquid crystal drive circuit 17. In S205, the CPU-A1 performs the same shutter operation process as in S202 described above, and the subsequent S2.
At 06, the CCD read operation processing similar to that at S203 described above is performed.

Then, in S207, the CPU-A1
Turns on the operation of the liquid crystal monitor by restarting the supply of power to the liquid crystal monitor and the TFT liquid crystal drive circuit 17 stopped by the processing of S204 described above. In S208,
The CPU-A1 performs a recording operation process, that is, a process of giving an instruction to the CPU-B9 to generate image data corresponding to the image signal read from the CCD 4 and record the image data on the recording medium 13. After this processing is completed, the processing based on this 2nd release is completed.

By the control processing by the CPU-1 described above, the power consumption by the liquid crystal monitor during the photographing operation started in response to the second release of the release button is eliminated, so that the voltage drop of the battery of the power source is reduced. As a result, the battery voltage will not drop below the predetermined value due to this shooting operation for a while, so the electric energy stored in the battery can be used more efficiently than before, and the usable time of the electronic camera is longer. It will be.

In the process based on the 2nd release, instead of performing the control to turn off the operations of the liquid crystal monitor and the TFT liquid crystal drive circuit 17, the brightness of the liquid crystal monitor is decreased as in the process based on the 1st release described above. For example, the control for reducing the amount of power consumed by the liquid crystal monitor may be performed.

In the above embodiment, TF
By controlling the brightness of the backlight that illuminates the T panel 18 from the back side, the display brightness of the liquid crystal monitor is changed to control the power consumption.
It is also possible to control the power consumption by changing the display brightness of the LCD monitor by controlling the brightness of the front light that illuminates the front of the LCD, and of course control the applied power for illumination in the self-illuminating LCD panel unit. You may do it. If the electronic camera is equipped with a self-luminous display monitor such as an LED display or an organic EL (Electro Luminescence) display, the power applied to the display monitor may be directly controlled.

[0045]

As described in detail above, in the electronic camera according to the present invention, while the automatic focusing means for automatically focusing the subject image represented in the picked-up image performs the focusing operation. Alternatively, while the shutter drive means for driving the shutter in response to the release operation is driving the shutter, the control for reducing the electric power applied to the display means for displaying an image is performed, thereby controlling the electronic camera. Since the electric energy stored in the battery used as the power source can be used more efficiently than before, the usable time of the electronic camera can be extended.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an electronic camera embodying the present invention.

FIG. 2 is a flowchart showing the processing contents of a shooting process performed by a CPU-A in response to a release button being pressed.

[Explanation of symbols]

1 CPU-A 2 EEPROM 3 lenses 4 CCD 5 Imaging circuit 6 A / D converter 7 Correction circuit 8 frame memory 9 CPU-B 10 FIFO memory 11 Recording medium I / F 12 buses 13 recording media 14 Video encoding circuit 15 Video output circuit 16 video output terminals 17 TFT LCD drive circuit 18 TFT panel 19 Backlight unit 20 actuators 21 Actuator drive circuit 22 External data I / F 23 Key matrix section 24 LCD display circuit 25 LCD panel 26 batteries 27 Power circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/225 G03B 3/00 A // H04N 101: 00 G02B 7/11 K N F term (reference) 2H011 AA03 DA05 2H051 AA08 EA14 EB09 EB20 GA00 GB09 2H081 CC69 DD06 2H102 AB17 BA01 BA02 BA06 BA21 BA22 BB03 5C022 AA13 AB67 AC42 AC73

Claims (7)

[Claims] 1. A display unit for displaying an image, an automatic focusing unit for automatically focusing a subject image represented in a picked-up image, and an automatic focusing unit for performing a focusing operation. An electronic camera comprising: a control unit that controls to reduce the power applied to the display unit. 2. The electronic camera according to claim 1, wherein the control unit controls to reduce the power by changing a display brightness of the display unit. 3. Display means for displaying an image, shutter drive means for driving a shutter in response to a release operation, and while the shutter drive means is driving the shutter,
An electronic camera comprising: a control unit that controls to reduce the power applied to the display unit. 4. The electronic camera according to claim 3, wherein the control unit controls to reduce the power by changing the display brightness of the display unit. 5. The electronic camera according to claim 3, wherein the control unit performs control to reduce the power by stopping the operation of the display unit. 6. Display means for displaying an image, automatic focusing means for automatically focusing a subject image represented in a captured image, shutter driving means for driving a shutter in response to a release operation, While the automatic focusing means is performing the focusing operation, and while the shutter driving means is driving the shutter,
An electronic camera comprising: a control unit that controls to reduce the power applied to the display unit. 7. The electronic camera according to claim 6, wherein the control unit controls to reduce the power by changing the display brightness of the display unit.