JP2004248059A - Electronic camera - Google Patents

Abstract

An object of the present invention is to prolong the state in which the electronic camera can be actually used by limiting or gently increasing the temperature of an electronic camera.
An electronic camera according to the present invention has at least three operation modes having different power consumptions, and includes a temperature detection unit and a control unit. The temperature detector detects the temperature of the electronic camera and outputs the detected temperature as an inspection temperature. Based on the inspection temperature, the control unit switches the operation mode in stages so as to operate with lower power consumption as the inspection temperature is higher, thereby suppressing the temperature rise. For this reason, a temperature lowering effect can be expected at an intermediate stage. Therefore, the time when the electronic camera can be actually used can be extended.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for suppressing a temperature rise of an electronic camera.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an electronic camera, the temperature inside the camera may increase due to heat generated by a system LSI chip for performing image processing, a battery, and the like. When the temperature inside the camera increases, noise included in the output signal of the image sensor increases, and there is a possibility that the image quality may deteriorate.
[0003]
Thus, Patent Document 1 proposes a method of executing one or more of the following heat generation countermeasure processing when the temperature in the camera exceeds a predetermined value. This heat generation countermeasure processing includes turning off the backlight, stopping the focus adjustment operation, prohibiting power supply to the flash device, turning off the camera power, prohibiting reproduction of image data in the recording medium, prohibiting recording on the recording medium, and the like. It is. As a result, the heat generation of the backlight and the battery is reduced, the rise in the temperature inside the camera is suppressed, and the noise included in the output signal of the image sensor is reduced.
[0004]
[Patent Document 1]
JP-A-2002-135636 (Section 5-7, FIG. 3-5)
[0005]
[Problems to be solved by the invention]
The invention of Patent Document 1 has excellent operational effects as described above. However, it is desirable that the rise in the temperature inside the camera can be suppressed as much as possible without turning off the backlight of the liquid crystal monitor or turning off the power of the camera. This is because inconveniences such as difficulty in shooting immediately and difficulty in confirming display contents on the liquid crystal monitor are considered.
[0006]
In addition, with the speeding up of the photographing operation and the image processing (higher frequency of the clock), there is a concern that the temperature of the system LSI chip will be further increased and the heat generated by the through current at the time of bus access. On the other hand, with the miniaturization of electronic cameras, it is difficult to radiate internally generated heat to the outside. Therefore, it is important to suppress heat generation.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide a technique for prolonging a state in which the electronic camera can be actually used by limiting or gently increasing the temperature of an electronic camera.
[0008]
[Means for Solving the Problems]
The electronic camera according to the first aspect has at least three operation modes having different power consumptions, and includes a temperature detection unit and a control unit. The temperature detector detects the temperature of the electronic camera and outputs the detected temperature as an inspection temperature. The control unit switches the operation mode based on the inspection temperature in a stepwise manner so as to operate with lower power consumption as the inspection temperature is higher.
[0009]
An electronic camera according to a second aspect is characterized in that, in the invention according to the first aspect, the following three points are provided. First, an image pickup unit that picks up an optical image formed by a photographing lens and generates image data is provided. Secondly, the image processing apparatus includes an image processing unit that performs image processing on image data generated by the imaging unit. Third, when the control unit switches the operation mode step by step, the operation frequency of a part of the image processing unit that performs image processing on the image data of the still image is first reduced.
[0010]
According to a third aspect of the present invention, in the second aspect of the invention, the control unit sets the operation mode to a higher operation frequency after the electronic camera starts shooting, and the image processing unit converts the still image into image data. After performing the image processing, the operation mode is returned to the one before the start of shooting. ].
According to a fourth aspect of the present invention, there is provided the electronic camera according to any one of the first to third aspects, wherein “when the operation mode with the lowest power consumption is set, the electronic camera is warned that the temperature of the electronic camera is high. The warning unit is provided. ].
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<Configuration of this embodiment>
FIG. 1 is a block diagram showing the configuration of the electronic camera of the present invention. In the figure, an electronic camera 10 includes an interchangeable photographing lens 14, a CCD 16, an analog signal processing unit 18, an A / D conversion unit 20, a timing generator 24, a system bus 28, a system LSI 32, an operation unit 36, a control CPU 40, a temperature sensor 44, an image memory (RAM) 48, a program memory (ROM) 52, a card interface 56, a replaceable memory card 60, a USB interface 64, and a USB (registered). (Trademark) 68, a monitor control unit 72, a display monitor 76, and a backlight 80.
[0012]
The analog signal processing unit 18 and the A / D conversion unit 20 perform image processing such as clamping, sensitivity correction, and A / D conversion on the pixel output from the CCD 16 to generate image data.
The system LSI 32 performs image processing on image data input from the A / D converter 20. Since the system LSI 32 has many image processing systems mounted on one semiconductor chip, the number of internal elements is large. Therefore, it is considered that the temperature of the system LSI 32 tends to be the highest in the electronic camera 10 of the present embodiment. Therefore, the temperature sensor 44 is fixed near the system LSI 32 (for example, on a printed wiring board on which the system LSI 32 is mounted).
[0013]
The control CPU 40 switches the operation mode of the electronic camera 10 stepwise based on the temperature inside the electronic camera 10 output as the inspection temperature T by the temperature sensor 44. Details of this operation will be described later. The control CPU 40 controls the system of the electronic camera 10 via the system bus 28.
The operation unit 36 has a button group (not shown) necessary for photographing and setting of the electronic camera 10 such as a power button and a release button.
[0014]
The functions of the other units, the photographing operation, and the image processing after image pickup are the same as those of the conventional electronic camera, and thus description thereof will be omitted.
FIG. 2 is a table (table data) showing an outline of the operation mode described above. As shown in FIG. 2, the electronic camera 10 has five operation modes of a normal high-speed mode, a medium-speed mode, a quasi-low-speed mode, a low-speed mode, and an ultra-low-speed mode in the order of higher power consumption (that is, higher operation speed). Have. Further, the electronic camera 10 has a sleep mode, and is set to one of these six modes. Hereinafter, how to read FIG. 2 will be briefly described.
[0015]
In the normal high-speed mode, the clock in the system LSI 32 is set to the maximum frequency of 90 MHz, the clock of the system bus 28 is set to 72 MHz, the communication frequency between the card interface 56 and the memory card 60 and the communication between the USB interface 64 and the USB 68 The frequency is set to 36 MHz. Further, for example, when the semi-low speed mode is set, the mode is switched to the low speed mode when the above-described inspection temperature T becomes 65 ° C. or higher, and is switched to the medium speed mode when the inspection temperature T becomes less than 55 ° C. .
[0016]
<Description of the operation of the present embodiment>
FIG. 3 is a flowchart showing an operation for suppressing a temperature rise in the electronic camera 10 described above. Hereinafter, this operation will be described according to the step numbers shown in FIG. 3 using FIG. 2 described above.
[Step S1]
When the power button is turned on, the control CPU 40 initializes each part of the electronic camera 10. Then, the control CPU 40 sets the operation mode of the electronic camera 10 to, for example, a normal high-speed mode (other than the ultra-low-speed mode in which the backlight 80 is turned off and a sleep mode as described later). .
[0017]
[Step S2]
The temperature sensor 44 detects the temperature inside the electronic camera 10 as the inspection temperature T and inputs the temperature to the control CPU 40.
[0018]
[Step S3]
The control CPU 40 determines whether the inspection temperature T is equal to or higher than T2 (70 ° C. in this example). If it is 70 ° C. or higher, the process proceeds to step S4. Further, the control CPU 40 determines whether or not the inspection temperature T is lower than T1 (50 ° C. in this example). If it is lower than 50 ° C., the process proceeds to step S5. If the above conditions are not satisfied (below 50 ° C. and below 70 ° C.), the process proceeds to step S6.
[0019]
[Step S4]
The control CPU 40 causes the display monitor 76 to display, for example, “Transition to sleep mode due to an increase in the temperature inside the camera” via the monitor control unit 72. ] Is displayed. After a lapse of a predetermined period from the display, the control CPU 40 executes a process for turning off each unit of the electronic camera 10 to set the sleep mode. Then, the operation of the electronic camera 10 is stopped.
Even in the sleep mode, the control CPU 40 operates in the standby state as long as the remaining battery (not shown) remains. Therefore, when the user operates the operation unit 36 in the sleep mode, the control CPU 40 initializes each unit as in step S1, and then proceeds to step S2.
When the inspection temperature T is 70 ° C. or higher, the power-off process of the electronic camera 10 may be executed after the warning is displayed instead of setting the sleep mode.
[0020]
[Step S5]
The control CPU 40 sets the electronic camera 10 to the normal high-speed mode by switching the clock frequency in the system LSI 32, the clock frequency of the system bus 28, and the like described in the description of FIG. 2 (corresponding to the dashed arrow in FIG. 1). . If the operation mode has already been set, the setting is not changed (the same applies to the description of steps S7 and S8 below). Then, the process proceeds to step S9.
[0021]
[Step S6]
The control CPU 40 determines whether the inspection temperature T is equal to or higher than T3 (68 ° C. in this example). If the temperature is higher than 68 ° C., the process proceeds to step S7. If the temperature is lower than 68 ° C., the process proceeds to step S8.
[0022]
[Step S7]
The control CPU 40 switches the above-described clock frequency and communication frequency in order to put the electronic camera 10 into the ultra-low speed mode. At the same time, the control CPU 40 causes the display monitor 76 to display a warning such as “operating in the ultra-low speed mode” via the monitor control unit 72. Thereby, the user can read "The temperature in the camera is currently high. Therefore, when the temperature inside the camera further rises, the mode is switched to the sleep mode, and each unit is turned off. 』I will be informed. Then, after a lapse of a predetermined period from this warning display, the backlight 80 is turned off. Thereafter, the process proceeds to step S9.
If a slightly reflective liquid crystal monitor is used as the display monitor 76, the display contents can be confirmed to some extent by ambient light even when the backlight 80 is turned off.
[0023]
[Step S8]
The control CPU 40 switches or continues the operation mode as described below based on the inspection temperature T, the current operation mode, and the table data shown in FIG. Note that this step is reached when the inspection temperature T is determined to be 50 ° C. or more and less than 68 ° C. in steps S3 and S6, and the sleep mode is not set here.
[0024]
(1) When the normal high-speed mode is set It is determined whether or not the inspection temperature T is 55 ° C. or higher, and if it is 55 ° C. or higher, the mode is switched to the medium speed mode. If the temperature is lower than 55 ° C., the operation mode is not changed.
(2) When the medium speed mode is set It is determined whether or not the inspection temperature T is 60 ° C. or higher, and if it is 60 ° C. or higher, the mode is switched to the quasi-low speed mode. If the temperature is lower than 60 ° C., the operation mode is not changed.
[0025]
(3) When set to the quasi-low speed mode It is determined whether or not the inspection temperature T is 65 ° C. or higher, and if it is 65 ° C. or higher, the mode is switched to the low speed mode. Further, it is determined whether or not the inspection temperature T is lower than 55 ° C., and if it is lower than 55 ° C., the mode is switched to the medium speed mode. Otherwise, the operation mode is not changed.
(4) When the low-speed mode is set It is determined whether or not the inspection temperature T is 68 ° C. or higher. If the temperature is 68 ° C. or higher, the mode is switched to the ultra-low speed mode by the same operation as in step S7. Further, it is determined whether or not the inspection temperature T is lower than 60 ° C., and if it is lower than 60 ° C., the mode is switched to the quasi-low speed mode. In cases other than these (when the temperature is 60 ° C. or more and less than 68 ° C.), the operation mode is not changed.
(5) When the ultra-low speed mode is set, it is determined whether or not the inspection temperature T is lower than 65 ° C., and when the temperature is lower than 65 ° C., the mode is switched to the low speed mode and the warning display is canceled. If the temperature is 65 ° C. or higher, the operation mode is not changed.
[0026]
Thereafter, the process proceeds to step S9. As shown in FIG. 2, it is desirable that switching between the operation modes has hysteresis. This is because, for example, when the inspection temperature T is 50 ° C. or more and less than 55 ° C., the predetermined temperature is determined regardless of the current operation mode, such as the medium speed mode, and when the inspection temperature T is 55 ° C. or more and less than 60 ° C. This is because the following problem is conceivable when the operation mode is switched. This means that when the inspection temperature T fluctuates slightly near the boundary temperature between the operation modes, the operation mode is switched many times.
[0027]
[Step S9]
The control CPU 40 determines whether or not the release button of the operation unit 36 is half-pressed. If half-pressed, the process proceeds to step S10; otherwise, the process returns to step S2.
[Step S10]
The control CPU 40 temporarily switches the electronic camera 10 to the normal high-speed mode. Then, the process proceeds to step S11.
[0028]
[Step S11]
The control CPU 40 and the system LSI 32 control the focus (AF) of the photographing lens 14, exposure control (set the aperture of the photographing lens 14, the exposure time, and the imaging sensitivity of the CCD 16 to appropriate values), and adjust the white balance before shooting. Get ready.
[Step S12]
The control CPU 40 determines whether or not the release button has been fully pressed. If the button has been fully pressed, the process proceeds to step S15; otherwise, the process proceeds to step S13.
[0029]
[Step S13]
The control CPU 40 determines whether or not the release button is half-pressed. If the half-press has been released, the process proceeds to step S14. If the half-press has been released, the process returns to step S12.
[Step S14]
The control CPU 40 returns the mode of the electronic camera 10 to the mode before switching to the normal high-speed mode in step S10. Then, the process returns to step S2.
[0030]
[Step S15]
A known shooting operation is performed, and the generated image data of the still image is input from the A / D converter 20 to the system LSI 32. The system LSI 32 performs white balance adjustment, gamma correction, color interpolation, color conversion, and color correction (for example, saturation enhancement processing) on the image data of the still image. Then, the process proceeds to step S16.
[0031]
[Step S16]
The control CPU 40 returns the mode of the electronic camera 10 to the mode before switching to the normal high-speed mode in step S10. Then, the process proceeds to step S17.
[0032]
[Step S17]
The system LSI 32 performs outline enhancement processing and image compression (for example, JPEG conversion) on the image data that has been subjected to the image processing in step S15. Then, the system LSI 32 records the compressed image data on the memory card 60 via the card interface 56.
Then, returning to step S2, the temperature sensor 44 and the control CPU 40 repeat the operation of detecting the inspection temperature T and resetting the operation mode. Since the temperature detection and the mode resetting operation are repeated in a sufficiently short period, the operation mode is switched stepwise unless there is a sudden rise in temperature.
The above is the description of the operation of the electronic camera 10 of the present embodiment.
[0033]
<Effect of this embodiment>
In the present embodiment, the temperature inside the electronic camera 10 is always detected as the inspection temperature T. Then, the operation mode is switched stepwise so as to operate at a lower speed and lower power consumption as the inspection temperature T is higher, and the temperature rise is suppressed (steps S5, S7, S8). For this reason, in the operation mode with lower power consumption than in the normal operation mode (normal high-speed mode in this example), an effect of lowering the temperature can be expected. Therefore, the actual usable time can be longer than that of the conventional electronic camera.
[0034]
In addition, in order to suppress the temperature rise by switching the operation mode in stages, unless there is a sudden rise in temperature, transition from the low-speed mode to the sleep mode without going through the ultra-low-speed mode with a warning display There is no. Therefore, the temperature rise of the electronic camera 10 can be suppressed without turning off the backlight 80 or setting the sleep mode as much as possible.
[0035]
When the temperature of the electronic camera 10 rises, the control CPU 40 first lowers the operating frequency of the system LSI 32 (see the transition from the normal high-speed mode to the low-speed mode in FIG. 2). As described above, the system LSI 32 is considered to be a portion where the temperature tends to be the highest in the electronic camera 10 of the present embodiment. That is, since the operating frequency of the portion where heat is most likely to be generated is lowered first, the temperature rise of the electronic camera 10 can be efficiently suppressed.
[0036]
In suppressing the above-mentioned temperature rise, the control CPU 40 temporarily sets the high-speed mode regardless of the inspection temperature T from when the release button is half-pressed until when the color correction processing is performed on the data of the captured image. . For this reason, it is possible to suppress a rise in the temperature of the electronic camera 10 while enabling the user to execute the next photographing quickly.
When the mode is switched from the low-speed mode to the ultra-low-speed mode, the backlight 80 is turned off after a predetermined period elapses after notifying the user that “the temperature in the camera is high” by a warning display. Switching to the sleep mode is also performed after a lapse of a predetermined period from the same warning display. For this reason, the backlight 80 is not turned off or switched to the sleep mode without prior notification to the user. Therefore, the electronic camera 10 can be protected from a rise in temperature while notifying the user of the situation (without misunderstanding that it is a failure).
[0037]
<Supplementary information of this embodiment>
[1] In this embodiment, an example has been described in which the backlight 80 is turned on until the low-speed mode, and the backlight 80 is turned off from the ultra-low-speed mode. The present invention is not limited to such an embodiment. The brightness of the backlight 80 may be reduced stepwise according to each operation mode. In this case, for example, 100% of the maximum luminance in the normal high-speed mode, 90% in the medium-speed mode, 80% in the sub-low-speed mode, 70% in the low-speed mode, and off in the ultra-low-speed mode and the sleep mode.
[0038]
[2] The example in which the temperature sensor 44 detects the ambient temperature of the system LSI 32 has been described. The present invention is not limited to such an embodiment. It is desirable that the temperature sensor detects the temperature of a portion of the electronic camera that is considered to be the highest in temperature. Alternatively, a plurality of temperatures may be detected by a plurality of temperature sensors, and the highest one of them may be used as the inspection temperature T for temperature control.
[0039]
Further, the temperature detection part is not limited to the inside of the electronic camera. For example, another temperature sensor (referred to as 44b) may be fixed on the housing (outside) of the electronic camera 10. In this case, the higher of the temperatures detected by the temperature sensors 44 and 44b may be used as the inspection temperature T for the temperature control. In this way, for example, even when the electronic camera 10 is placed on the hood of a car and the temperature of the housing of the electronic camera 10 rises due to an increase in external temperature, the electronic camera 10 is protected from heat. it can.
[0040]
[3] The example has been described in which the normal high-speed mode is performed regardless of the inspection temperature T from when the release button is half-pressed until when color correction is performed on the data of the captured image. The present invention is not limited to such an embodiment. One or more of the processes (white balance adjustment, gamma correction, color interpolation, color conversion, color correction) performed in step S15 may be performed in step S17.
Alternatively, in step S15, the processing may be performed up to the outline emphasis processing.
Alternatively, in step S15, image compression may be performed. In this case, since the size of the image data remaining in the image memory is reduced, the possibility that the number of frames that can be continuously shot at high speed is reduced is reduced. It should be noted that there is no problem if the recording process on the memory card 60 is performed at a low speed after the end of the next shooting. This is because the image data may be left in the image memory 48.
[0041]
[4] An example has been described in which a warning is displayed on the display monitor 76 when switching to the ultra-low speed mode or the sleep mode. The present invention is not limited to such an embodiment. The warning method may be another form such as a sound.
[0042]
[5] The example in which the electronic camera 10 is set to one of the five operation modes and the sleep mode has been described. The present invention is not limited to such an embodiment. The number of operation modes may be 7 or more or 5 or less (however, at least three are necessary). Similarly, the temperatures and frequencies shown in FIG. 2 are examples disclosed for reference and do not limit the present invention.
[0043]
[6] An example has been described in which after the release button is half-pressed in step S9, the mode is switched to the normal high-speed mode in step S10. The present invention is not limited to such an embodiment. For example, step S10 may be omitted, and after the release button is fully pressed in step S12 (before step S15), the mode may be switched to the normal high-speed mode.
[0044]
Alternatively, steps S10 and S16 may be omitted. That is, even when the electronic camera 10 starts the preparatory operation immediately before photographing by half-pressing the release button, the electronic camera 10 may not be shifted to the normal high-speed mode. In this case, the user may feel a sense of incongruity or inconvenience due to a decrease in the operation speed. However, a situation in which a load of performing high-speed operation at high temperature is applied to the electronic camera 10 does not occur. Therefore, it is possible to minimize the adverse effect of the temperature rise on each part of the electronic camera 10.
[0045]
<Correspondence with Claims>
Finally, the correspondence between the claims and the present embodiment will be described. In addition, the following correspondence is an interpretation shown for reference, and does not limit the present invention.
The temperature detector in the claims corresponds to the temperature sensor 44.
The control unit described in the claims corresponds to the control CPU 40.
[0046]
The imaging unit described in the claims corresponds to the CCD 16, the analog signal processing unit 18, and the A / D conversion unit 20.
The image processing unit described in the claims corresponds to the system LSI 32.
The “part of the image processing unit that performs image processing on the image data of a still image” in the claims corresponds to “the function of a system LSI that performs image processing up to step S15 on image data of a captured still image”. .
[0047]
After the photographing is started, the operation mode is set to a higher operation frequency, and after the image processing unit performs image processing on the image data of a still image, the operation mode is changed to a state before the photographing starts. "Return to one" corresponds to "function of control CPU 40 for returning to the mode before switching to normal high-speed mode in step S10 and switching to normal high-speed mode in step S16".
[0048]
“The operation mode with the lowest power consumption” in the claims corresponds to an ultra-low speed mode.
The “display unit that displays a warning that the temperature is high” in the claims corresponds to the display monitor 76 and the function of the control CPU 40 that displays a warning on the display monitor 76 (see step S7).
[0049]
【The invention's effect】
In the present invention, the temperature of the electronic camera is detected, and the operation mode is switched stepwise so that the higher the detected temperature, the lower the power consumption. For this reason, an effect of lowering the temperature can be expected in the middle stage (low power consumption operation mode). Therefore, the time when the electronic camera can be actually used can be extended.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an electronic camera of the present invention.
FIG. 2 is a table illustrating an outline of an operation mode of the electronic camera of the present invention.
FIG. 3 is a flowchart showing the operation of the electronic camera of the present invention.
[Explanation of symbols]
10 electronic camera 14 shooting lens 16 CCD
18 Analog signal processing unit 20 A / D conversion unit 24 Timing generator 28 System bus 32 System LSI
36 operation unit 40 control CPU
44 Temperature sensor 44
48 image memory 52 program memory 56 card interface 60 memory card 64 USB interface 64
68 USB
72 monitor controller 76 display monitor 80 backlight

Claims (4)

An electronic camera having at least three operation modes having different power consumptions,
A temperature detection unit that detects the temperature of the electronic camera and outputs it as an inspection temperature;
An electronic camera, comprising: a control unit configured to switch the operation mode in a stepwise manner based on the inspection temperature so as to operate with lower power consumption as the inspection temperature increases. The electronic camera according to claim 1,
An imaging unit that captures an optical image formed by a photographing lens and generates image data, and an image processing unit that performs image processing on the image data generated by the imaging unit.
The electronic camera according to claim 1, wherein the control unit firstly lowers an operation frequency of a part of the image processing unit that performs image processing on the image data of the still image when the operation mode is switched stepwise. The electronic camera according to claim 2,
The control unit sets the operation mode to a high operation frequency after the electronic camera starts shooting, and after the image processing unit performs image processing on the image data of a still image, sets the operation mode to the shooting mode. An electronic camera characterized by returning to the one before the start. The electronic camera according to any one of claims 1 to 3,
An electronic camera, comprising: a warning unit that warns that the temperature of the electronic camera is high when the operation mode with the lowest power consumption is set.

Images