Television – Camera – system and detail – With electronic viewfinder or display monitor
Reexamination Certificate
1999-05-20
2003-09-09
Ho, Tuan (Department: 2612)
Television
Camera, system and detail
With electronic viewfinder or display monitor
C348S231990, C345S212000
Reexamination Certificate
active
06618089
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a display apparatus and an electronic camera, and more particularly to an LCD apparatus, which is applied to an electronic camera such as a digital camera, and an electronic camera.
2. Description of Related Art
Conventionally, to display a still image captured by a digital camera, etc. on a liquid crystal display (LCD), image data of the still image is stored in an image memory, the image data is then read from the image memory and converted into a standard video signal (e.g., NTSC or PAL) or a video signal suitable for the LCD. The video signal is applied to the LCD so that the still image can be displayed on the LCD.
During the display, the image memory is continuously accessed at a constant frame rate through a memory bus. Thus, in order to retrieve the image data from the image memory for another purpose of compressing the image data or recording the image data in an external storage medium, etc., it is necessary to stop the display temporarily or to retrieve the image data during only vertical and horizontal blanking periods.
If the display is temporarily stopped, it is impossible to confirm the image during that time. If the image data is retrieved during the vertical and horizontal blanking periods, it takes a long time to process the data as a whole, since the vertical and horizontal blanking periods are very short. For example, when an image of 640×480 pixels is displayed by means of the NTSC video signal,
“One-frame period” ={fraction (1/30)}=33.3 msec, and “Vertical blanking period” =“One-frame period” ×(525−480)/525=({fraction (1/30)})×{fraction (45/525)}∞2.86 msec.
That is, if only the vertical blanking periods are used, the data is processed for only 2.86msec in each vertical synchronous period. Even if the horizontal blanking periods are also used, the processing time increases only a little.
There is proposed an electronic camera with an LCD monitor, which can also serve as an electronic finder for enabling a user to determine what will be included in the picture by displaying moving images captured through an imaging unit of the camera. This electronic camera, however, has a problem of consuming a large amount of electricity during the use of the LCD monitor.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a display apparatus and an electronic camera that reduce the consumption of electricity while an image is displayed on a display unit.
It is another object of the present invention to provide an electronic camera, which is capable of performing a signal processing at a high speed while displaying an image on the display unit.
To achieve the above-mentioned object, the present invention is directed to a display apparatus comprising: a display unit; a video signal generator for intermittently outputting a video signal; and a display unit driver for intermittently receiving the video signal from the video signal generator and applying the video signal and drive pulses to the display unit; wherein, while the display unit driver does not receive the video signal from the video signal generator, the display unit driver suspends applying of at least a part of the drive pulses to the display unit and maintains a currently-displayed image on the display unit.
To achieve the above-mentioned object, the present invention is also directed to an electronic camera comprising: an imaging device for converting light from a subject into an image signal; an imaging unit for obtaining image data representing the subject by driving the imaging device; a display unit; a video signal generator for controlling the imaging unit to intermittently drive the imaging device, intermittently converting the image data obtained through the imaging device and the imaging unit into a video signal, and intermittently outputting the video signal; and a display unit driver for intermittently receiving the video signal from the video signal generator and applying the video signal and drive pulses to the display unit; wherein, while the display unit driver does not receive the video signal from the video signal generator, the display unit driver suspends applying of at least a part of the drive pulses to the display unit and maintains a currently-displayed image on the display unit.
To achieve the above-mentioned object, the present invention is directed to an electronic camera comprising: an imaging device for converting light from a subject into an image signal; an imaging unit for obtaining image data representing the subject by driving the imaging device; an image memory for storing the image data; a display unit; a video signal generator for intermittently reading the image data from the image memory, intermittently converting the image data read from the image memory into a video signal, and intermittently outputting the video signal; and a display unit driver for intermittently receiving the video signal from the video signal generator and applying the video signal and drive pulses to the display unit; wherein, while the display unit driver does not receive the video signal from the video signal generator, the display unit driver suspends applying of at least a part of the drive pulses to the display unit and maintains a currently-displayed image on the display unit.
The display unit may comprise an LCD.
The present invention has been developed in view of the fact that some kinds of display units including the LCD can continue displaying the image for a constant period by applying voltage corresponding to the image data to each element between the terminals thereof, even if the application of the video signal and the drive pulses is suspended. According to the present invention, the video signal is intermittently applied to the display unit. While no video signal is applied, the drive pulse for the display unit is not generated, and the display unit continues displaying the currently-displayed image. It is therefore possible to stop driving the imaging device and stop reading the image data from the image memory while no video signal is applied. This significantly reduces the consumption of electricity. Stopping driving the display unit has no problem if the display unit displays a still image. If the display unit displays a moving image, the moving image is displayed intermittently and cannot be displayed smoothly, but the display unit LCD can satisfactorily serve as the electronic finder.
To achieve the above-mentioned object, the present invention is directed to an electronic camera comprising: an imaging device for converting light from a subject into an image signal; an imaging unit for obtaining image data representing the subject by driving the imaging device; an image memory for storing the image data; a display unit; a video signal generator for intermittently reading the image data from the image memory, intermittently converting the image data read from the image memory into a video signal, and intermittently outputting the video signal, the video signal generator being capable of continuously reading the image data from the image memory, continuously converting the image data read from the image memory into the video signal, and continuously outputting the video signal; a signal processor for accessing the image memory to perform a signal processing while the video signal generator does not read the image data from the image memory; and a display unit driver for intermittently receiving the video signal from the video signal generator and applying the video signal and drive pulses to the display unit; wherein, while the display unit driver does not receive the video signal from the video signal generator, the display unit driver suspends applying of at least a part of the drive pulses to the display unit and maintains a currently-displayed image on the display unit.
According to the present invention, in the case of performing a signal processing (e.g., compressing the image data and recording t
Birch & Stewart Kolasch & Birch, LLP
Fuji Photo Film Co. , Ltd.
Ho Tuan
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