Image recording/reproducing apparatus displaying object images and reproduced images

An image display apparatus for displaying an image represented by an image signal corresponding to an object and a reproduced image represented by an image signal reproduced from a storage medium includes a display device provided with a first display mode that permits binary image displays at a low-brightness level and at a high-brightness level and a second display mode that permits multi-level image displays at the low-brightness level, the high-brightness level and at an intermediate level. The brightness level in the display device is set to be lower when the display device displays in the first display mode than when the display device displays in the second display mode. Thus, a low power consumption, easy-to-use and long battery life image display apparatus is provided.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an image display apparatus having a 
display device for presenting an image represented by an image signal 
corresponding to an object and a reproduced image represented by an image 
signal reproduced from a storage medium. 
2. Description of the Related Art 
Electronic still video cameras and VCR-integrated cameras are examples of 
an image display apparatus having a display device for presenting an image 
represented by an image signal corresponding to an object and a reproduced 
image represented by an image signal reproduced from a storage medium. 
Some conventional electronic still cameras and VCR-integrated cameras are 
not equipped with a display device for presenting an image being picked up 
or an image being reproduced. These conventional apparatuses are provided 
with individual marks associated with dials and switches that are used for 
setting imaging parameters during a recording operation and reproducing 
parameters during a reproducing operation, and are also provided with a 
dedicated display for presenting settings. When a diversity of parameters 
are set in these apparatuses during an image recording or reproducing 
operation, the dials and switches are operated while monitoring the 
dedicated display. 
Some electronic video cameras and VCR-integrated cameras have a display 
device for presenting an image being picked up or an image being 
reproduced. To set imaging parameters during a recording operation and 
reproducing parameters during a reproducing operation, these apparatuses 
generate character image signals representing characters and symbols 
corresponding to settings in response to the positions of the dials and 
switches. The character images represented by the character image signals 
are superimposed on the picked image or reproduced image on the display 
device. An operator operates the dials and switches for proper settings 
while monitoring the content presented on the display device. 
Considering the portability of these conventional apparatuses, 
miniaturization of the battery as a power source may be contemplated. 
However, a smaller battery means a smaller capacity and a shorter battery 
operation time allowed for the apparatus. 
As described above, the electronic video cameras and VCR-integrated cameras 
that have a display device for presenting an image being picked up and an 
image being reproduced take the following series of steps in the parameter 
setting: a character image signal representing characters and symbols 
corresponding to the settings of dials and switches is generated, the 
character image represented by the character image signal is superimposed 
on a picked image or a reproduced image on the display device, and an 
operator operates the dials and switches for proper parameter setting 
while monitoring the content presented on the display device for 
verification. Throughout the above steps, the battery constantly feeds 
power to the display device, and operation time is accordingly shortened. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an image display 
apparatus free from the above problems. 
It is another object of the present invention to provide an image display 
apparatus that consumes less power without degrading ease of use. 
The image display apparatus of the present invention, in one aspect, for 
presenting an image represented by an image signal corresponding to an 
object and a reproduced image represented by an image signal reproduced 
from a storage medium, comprises: 
display means, provided with a first display mode that permits binary image 
displays at a low-brightness level and at a high-brightness level and a 
second display mode that permits multi-level image displays of the 
low-brightness level, the high-brightness level and an intermediate level, 
for presenting the image represented by the image signal corresponding to 
the object and the reproduced image represented by the image signal 
reproduced from the storage medium, and 
control means for controlling a brightness level in the display means to be 
lower when the display means displays in the first display mode than when 
the display means displays in the second display mode. 
It is yet another object of the present invention to provide an image 
display apparatus that operates for a long period of time. 
The image display apparatus of the present invention, in another aspect, 
for presenting an image represented by an image signal corresponding to an 
object and a reproduced image represented by an image signal reproduced 
from a storage medium, comprises: 
display means, provided with a first display mode for presenting a 
diversity of information when imaging parameters for the object are set 
and when reproducing parameters for the image signal reproduced from a 
storage medium, and a second display mode for presenting the picked image 
and the reproduced image, for presenting the image represented by the 
image signal corresponding to the object and the reproduced image 
represented by the image signal reproduced from the storage medium, and 
control means for controlling a driving frame rate in the display means to 
be lower when the display means displays in the second display mode than 
when the display means displays in the first display mode.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 is a block diagram showing a image recording and reproducing 
apparatus according to one embodiment of the present invention. 
Each of the elements shown in block outline in FIG. 1, as well as in FIGS. 
2 and 5, is well known per se, and a specific type of construction is not 
critical to carrying out the invention or to a disclosure of the best mode 
for carrying out the invention. 
Shown in FIG. 1 are an imaging lens 1 for forming an image of an object on 
the image plane of an image pickup device, an image pickup device 2 for 
converting the image of the object focused by the imaging lens 1 into an 
electrical signal (hereinafter referred to as an image signal), an 
analog/digital converter (hereinafter referred to as an A/D converter) 3 
for analog-to-digital converting the image signal output from the image 
pickup device 2 into a digital signal, a memory module 4 for storing the 
digital image signal (hereinafter referred to as image data) from the A/D 
converter 3 in the course of process of the image data, a signal 
processing module 5 for subjecting the image data from the A/D converter 3 
to a diversity of signal processes, and a timing generator 6 for 
generating various driving pulses for operating the image pickup device 2, 
A/D converter 3 and signal processing module 5. 
Also shown in FIG. 1 are a liquid crystal display device 7 for presenting 
in a visible format the content of the image data output from the A/D 
converter 3, a backlight module 8 for illuminating the display section of 
the liquid crystal display device 7 from its back side, a driving circuit 
9 for receiving the image data from the A/D converter 3, driving the 
liquid crystal display device 7 based on the image data being input, and 
selectively outputting to the backlight module 8 two types of driving 
pulses having different pulse widths as shown in FIGS. 4A-4C, an image 
data memory 10 for storing the image data to be presented on the liquid 
crystal display device 7, and a memory controller 11 for controlling the 
input and output of image data to and from each of the memory module 4, 
signal processing module 5, and image data memory 10. 
Further shown in FIG. 1 are a recording module 12 for recording on a 
storage medium the image data from the A/D converter 3, an operation panel 
13 for inputting command signals and setting signals to a system control 
module 14 to be described later, when an operator operates the apparatus 
for commands and settings, and the system control module 14 for 
controlling the timing generator 6, driving circuit 9, and memory 
controller 11 according to the commands input through the operation panel 
13. 
The recording operation of the image recording and reproducing apparatus 
shown in FIG. 1 is now discussed. 
The image recording and reproducing apparatus is now switched on. The 
system control module 14 monitors the status of a switch arranged in the 
operation panel 13 for selecting an operation mode. When the switch 
selects a recording mode, the apparatus is put into an imaging operation. 
In the imaging operation, the image pickup device 2 converts the image 
focused through the imaging lens 1 into an image signal, which is then 
applied to the A/D converter 3. The A/D converter 3 A/D converts the image 
signal into image data, which is then fed to the memory controller 11. 
The memory controller 11 stores the image data in its memory module 4. Once 
the image data covering one page is stored in the memory module 4, the 
memory controller 11 read the image data stored in the memory module 4, 
and outputs it to the signal processing module 5 to subject the image data 
to signal processings including color conversion, data thinning, 
averaging, and number-of-pixel adjustment processings. 
The image data, after being subjected to various types of processings at 
the signal processing module 5, is transferred to the image data memory 10 
by the memory controller 11. The image data stored in the image data 
memory 10 is read sequentially to the driving circuit 9, and is then 
presented on the liquid crystal display device 7 as a visible image. 
When a release switch arranged in the operation panel 13 for starting 
recording is pressed in the course of the above imaging operation, the 
apparatus is shifted to an image recording operation. The image data 
output from the A/D converter 3 is input to the memory controller 11 and 
is then stored in the memory module 4. 
The image data stored in the memory module 4 is subjected to data 
compression for recording through the signal processing module 5, and is 
then stored in a storage medium such as a memory card in the recording 
module 12. 
The reproducing operation of the image recording and reproducing apparatus 
shown in FIG. 1 is now discussed. 
Referring to FIG. 1, the system control module 14 monitors the status of 
the switch arranged in the operation panel 13 for selecting an operation 
mode. When the switch selects a reproducing mode, the apparatus is put 
into a reproducing mode. 
In the reproducing mode, the memory controller 11 reads desired image data 
out of a plurality of image data stored in the storage medium in the 
recording module 12 according to an image selection instruction from the 
operation panel 13. The read image data is stored in the memory module 4. 
Once the image data covering one page is stored in the memory module 4, 
the memory controller 11 reads the image data from the memory module 4, 
and outputs it to the signal processing module 5 to subject the image data 
to signal processings for the reproducing operation, including color 
conversion, data thinning, averaging, and number-of-pixel adjustment 
processings. 
The image data, after being subjected to various types of processings at 
the signal processing module 5, is transferred to the image data memory 10 
by the memory controller 11. The image data stored in the image data 
memory 10 is read sequentially to the driving circuit 9, and is then 
presented on the liquid crystal display device 7 as a visible image. 
FIG. 2 is a block diagram showing, as a first embodiment of the present 
invention, one arrangement of the driving circuit 9 in the image recording 
and reproducing apparatus of FIG. 1. FIGS. 4A-4C are waveform diagrams of 
backlight driving pulses the driving circuit 9 of FIG. 2 outputs to the 
backlight module 8. 
Referring to FIG. 2, a clock pulse output from a clock generator 9a in the 
driving circuit 9 is counted by a counter 9b. Count data corresponding to 
a count output from the counter 9b is supplied to each of decoders 9c and 
9d. The counter 9b is reset in synchronization with a horizontal 
synchronization signal (refer to FIG. 4A) supplied by the system control 
module 14. 
The decoders 9c and 9d decode count data, having different counts, to 
output positive backlight driving pulses having different pulse widths as 
shown in FIGS. 4B and 4C. In response to a control signal from the system 
control module 14, a switch 9e selects and outputs one of the backlight 
driving pulses output from the respective decoders 9c and 9d, to a 
backlight driving circuit 9f. The backlight driving circuit 9f drives the 
backlight module 8 based on the backlight driving pulse supplied by one of 
the decoders 9c and 9d via the switch 9e, and then illuminates from behind 
the display section of the liquid crystal display device 7 driven by a 
liquid crystal display driving circuit 9g. 
FIG. 3 is a flow diagram showing the backlight driving operation of the 
driving circuit 9 shown in FIG. 2. 
Referring to the flow diagram shown in FIG. 3, the backlight driving 
operation in the image recording and reproducing apparatus according to 
the first embodiment of the present invention is now discussed. 
When the image recording and reproducing apparatus is switched on, the 
system control module 14 checks the statuses of switches arranged on the 
operation panel 13 (step S101). 
When the recording mode or the reproducing mode is selected by the mode 
selection switch on the operation panel 13, the system control module 14 
outputs the control signal to the switch 9e in the driving circuit 9 shown 
in FIG. 2, connects the switch 9e to the output of the decoder 9c, and 
thus supplies to the backlight driving circuit 9f the backlight driving 
pulse "a" (having a pulse width of 6.0 .mu.s, for example) shown in FIG. 
4B (step S102). 
When a parameter setting mode is selected by the mode selection switch on 
the operation panel 13 to set a diversity of parameter values in the 
recording mode or reproducing mode (settings for an exposure, an exposure 
time, a self-timer, and reproduction method of multiple images, for 
example), the system control module 14 issues the control signal to the 
switch 9e in the driving circuit 9 shown in FIG. 2. The system control 
module 14 connects the switch 9e to the output of the decoder 9d, and thus 
supplies to the backlight driving circuit 9f the backlight driving pulse 
"b" (having a pulse width of 4.0 .mu.s, for example) shown in FIG. 4C 
(step S103). 
When the display device presents text-based information as in the parameter 
setting mode, a difference in brightness level between a low-brightness 
display area (a background display, for example) and a high-brightness 
display area (text, for example) is great on a display screen with an 
intermediate brightness level area marginally occupying the entire display 
screen. Thus, the pulse width of the backlight driving pulse supplied to 
the backlight driving circuit 9f is set shorter than during the 
recording/reproducing mode. Even if the intensity of light for back 
lighting is lowered to reduce the brightness on the entire screen, the 
content displayed on screen is still distinctly recognized. Furthermore, 
by lowering the intensity of light, the power consumption of the backlight 
module 8 is reduced as well, leading to a longer battery operation time 
for the image recording and reproducing apparatus. 
FIG. 5 is a block diagram showing, as a second embodiment of the present 
invention, another arrangement of the driving circuit 9 in the image 
recording and reproducing apparatus of FIG. 1. The construction of the 
recording and reproducing apparatus in the second embodiment remains 
identical to that of the recording and reproducing apparatus in the first 
embodiment except for the driving circuit 9. 
Referring to FIG. 5, two clock generators 9h and 9i in the driving circuit 
9 output respective clock pulses having different clock frequencies. The 
clock pulses output from the clock generators 9h and 9i are fed to a 
switch 9j that is controlled by a control signal from the system control 
module 14. The switch 9j feeds one of the clock pulses output from the 
clock generators 9h and 9i to a counter 9k. The counter 9k counts the 
clock pulse fed from one of the clock generators 9h and 9i via the switch 
9j, and feeds to the decoder 91 count data corresponding to its output 
count. 
The decoder 91 decodes the count data fed by the counter 9k, and outputs a 
positive backlight driving pulse to a backlight driving circuit 9m. The 
backlight driving circuit 9m drives the backlight module 8 based on the 
backlight pulse fed by the decoder 91, to illuminate from back the display 
section of the liquid crystal display device 7 that is driven by the 
crystal driving circuit 9n based on the clock pulse supplied by one of the 
clock generators 9h and 9i via the switch 9j. 
FIG. 6 is a flow diagram showing a liquid crystal display driving operation 
by the driving circuit 9 shown in FIG. 5. 
Referring to the flow diagram shown in FIG. 6, discussed is the driving 
operation of the liquid crystal display device in the image recording and 
reproducing apparatus according to the second embodiment of the present 
invention shown in FIGS. 1 and 5. 
When the image recording and reproducing apparatus is switched on, the 
system control module 14 checks the status of switches arranged on the 
operation panel 13 (step S201). 
When the recording mode or the reproducing mode is selected by the mode 
selection switch on the operation panel 13, the system control module 14 
outputs the control signal to the switch 9j in the driving circuit 9 shown 
in FIG. 5, connects the switch 9j to the output of the clock generator 9h, 
and thus supplies to a liquid crystal display circuit 9n a clock pulse of 
14.31 MHz, for example (step S202). 
When a parameter setting mode is selected by the mode selection switch on 
the operation panel 13 to set a diversity of parameter values in the 
recording mode or reproducing mode (settings for an exposure, an exposure 
time, a self-timer, and reproduction method of multiple images, for 
example), the system control module 14 issues the control signal to the 
switch 9j in the driving circuit 9 shown in FIG. 5. The system control 
module 14 connects the switch 9j to the output of the clock generator 9i, 
and thus supplies to the liquid crystal display driving circuit 9n a clock 
pulse of 7.16 MHz, for example (step S203). 
During the parameter setting mode, the driving rate of the liquid crystal 
display device 7 in the liquid crystal display circuit 9n in the driving 
circuit 9 is approximately half the rate during the recording mode or 
reproducing mode. 
When the display device presents text-based information as in the parameter 
setting mode, a change in a text display section on the display screen is 
small. Even if the driving rate of the liquid crystal display device 7 is 
set to be approximately half the rate during the recording mode or 
reproducing mode, no difficulty is presented in viewing the content 
displayed. Reducing the driving rate of the liquid crystal display device 
7 lowers the power consumption by the liquid crystal display device 7. As 
a result, a battery operation time of the image recording and reproducing 
apparatus is prolonged. 
As described above, the present invention presents an image recording and 
reproducing apparatus which features low power consumption, easy-to-use, 
and long battery life characteristics.