JPH04184484A - Electronic still camera - Google Patents

Abstract

PURPOSE:To reduce the electric power consumption of a view finder without impairing the operability at the time of still photographing by turning on the back light illumination of the view finder only for the prescribed period of time at the time of changing a photographing mode and at time of standing by for photographing. CONSTITUTION:A switch 63 is controlled by a system control circuit 40 to turn on an a lamp 52 to turn on when a shutter release key 42 is pushed down to a 1st stage. Then, a liquid crystal display element 51 of the view finder 50 is subjected to back light illumination by the lamp 52 and the various operations before photographing, such as focus adjustment, are smoothly progressed. The lamp 52 turns on as well to allow the easy recognition of the photographing modes displayed on the liquid crystal display element 51 of the view finder even when a photographing mode setting key 41 is pressed and the respective photographing modes of shutter priority, diaphragm priority, program, and manual are changed. The voltage consumption of the view finder is decreased in this way without impairing the operability at the time of photographing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic still camera equipped with an electronic viewfinder.

[Summary of the Invention] This invention provides an electronic still camera equipped with a viewfinder having a backlit liquid crystal display, in which the backlight of the viewfinder is turned on for a predetermined period when changing the shooting mode and during shooting standby. This reduces the power consumption of the viewfinder without impairing operability during still photography.

[Prior Art] Conventionally, for example, in an electronic still camera using a solid-state image sensor such as a two-dimensional CCD type image sensor, the aperture and the electronic shutter function of the solid-state image sensor are controlled based on the amount of imaging light. As a result, an electronic still camera that allows the use of an electronic viewfinder is known (see Japanese Patent Laid-Open No. 1-181391, etc.).

First, a conventional electronic still camera will be described with reference to FIGS. 3 and 4.

In FIG. 3, (10) is an optical system, and the lens (
11), an aperture (12) and an optical shutter (13), the aperture (12) and the optical shutter (13) are each accompanied by control mechanisms (14) and (15>), and the lens (11)
) is controlled.

(20) is an imaging system, which is equipped with a CC'D type solid-state image sensor (21) as described above, and this solid-state image sensor (21) has an electronic shutter function circuit that controls its charge accumulation period, etc. (22) is involved.

The output of the solid-state image sensor (21) is sent to the amplifier (23).
The light amount detection circuit (24) and the video signal processing circuit (
25), and this video signal processing circuit (25) is commonly supplied to the video signal processing circuit (25).
5) is sent to the magnetic head (26) via the recording circuit (26).
27), and is recorded on a video floppy FD, and is also supplied to an electronic viewfinder (50), which will be described later, to monitor the subject image.

(30) is a floppy drive control circuit which controls the rotation of the floppy drive motor (31) and controls the magnetic head (27) via a tracking mechanism (not shown).
) and the video floppy FD.

(40) is a system control circuit (microcomputer)
A shutter release key (42) is connected to a shooting mode setting key (41) for setting the aperture value and shutter speed in correspondence with shutter priority, aperture priority, and program shooting modes. At the same time, the output of the light amount detection circuit (24) is supplied. From this system control circuit (40), an aperture control mechanism (14), an optical shutter control mechanism (15) and an electronic shutter function circuit (22) are connected.
), and control signals are also supplied to the video signal processing circuit (25), the recording circuit (27), and the floppy drive control circuit (30).

In the above-mentioned electronic still camera, the charge accumulation period of the solid-state image sensor can be controlled based on the light amount information of the imaging light, and the exposure amount of the solid-state image sensor can always be kept within an appropriate range. This makes it possible to match the exposure state when monitoring with a small picture tube or an electronic viewfinder using a liquid crystal display element to the exposure state at the time of photographing.

As shown in FIG. 4, the viewfinder (50) includes a liquid crystal display element (51) and a backlight lamp (
52) and a light guide member (53). The output of the video signal processing circuit (25) of the imaging system (20) is supplied to the liquid crystal display element (51) via a drive circuit (not shown), and an eyepiece ( 54) is provided.

As the lamp (52), for example, a cold cathode fluorescent lamp whose power consumption is about IW is used, and the light from the lamp (52) is
The liquid crystal display element (51) is illuminated from the back side through the light guide member (53). On the back of the light guide member (53), outside light is taken in through the opening of the finder case (not shown), and when the outside light is bright, the lamp (52) is turned off or dimmed to reduce the backlight illumination power. (See Japanese Unexamined Patent Publication No. 64-4181, etc.).

[Problems to be Solved by the Invention] By the way, the above-mentioned viewfinder (50) has been proposed for use in a video camera for moving images, and is always in operation in recording mode.

However, with electronic still cameras, even in recording mode, it is sufficient that the viewfinder is operating when still images are taken. Therefore, the always-operating viewfinder described above has a problem in that it consumes unnecessary power.

On the other hand, if the power supply to the viewfinder is limited to the time of still image shooting in order to save power, a problem arises in that the screen becomes distorted when the viewfinder starts operating, which impedes smooth shooting operations.

In view of the above, an object of the present invention is to provide an electronic still camera that can reduce power consumption of a viewfinder without impairing operability during still photography.

[Means for Solving the Problems] The first invention includes an imaging means (21), a liquid crystal image display means (51) for displaying a video signal from the imaging means, and a backlight illumination means (52). In an electronic still camera that includes a viewfinder (50) and a switch (42) that can set the imaging drive circuit (40) to two stages, a standby state and an operating state, an illumination control means ( 63), when a switch is operated to set the imaging drive circuit to a standby state, the illumination control means turns on the backlight illumination means for a predetermined period, and turns off or off the backlight illumination means for the remaining period. This is an electronic still camera designed to reduce light.

A second aspect of the present invention includes an imaging means (21), a switch (41) for changing the imaging mode, a liquid crystal image display means (51) for displaying the video signal from the imaging means and the imaging mode, and a backlight. In an electronic still camera equipped with a viewfinder (50) having an illumination means (52), an illumination control means (63) for controlling the backlight illumination means is provided, and when the imaging mode is changed by operating a switch, the illumination In this electronic still camera, the control means turns on the backlight illumination means for a predetermined period, and turns off or dims the backlight illumination means during the remaining period.

[Operations] According to this configuration, the power consumption of the viewfinder is reduced without impairing the operability during still photography.

[Embodiment] Hereinafter, an embodiment of an electronic still camera according to the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, parts corresponding to those in FIGS. 3 and 4 are given the same reference numerals, and some explanations will be omitted.

In the embodiment shown in FIG. 1, for example, a power source (61) using a secondary battery is connected to a floppy drive control circuit (30) and a system control circuit (40) via a main switch (62).
) and, although not shown, are commonly connected to various parts such as the liquid crystal display element (51) of the viewfinder (50) and its drive circuit (not shown). A power source (61) is further connected to the backlight illumination lamp (52) of the view finder (50) via a lighting control switch (63). Opening and closing of the switch (63) is controlled by the system control circuit (40).

The rest of the structure is the same as that shown in FIGS. 3 and 4 above.

Next, the operation of one embodiment of the present invention will be described with reference to FIG.

First, the main switch (62) is turned on by the user (step Sl), power is supplied to each part, and the camera and viewfinder (50) are turned on.

Next, under the control of the system control circuit (40), the lighting control switch (63) is turned on, and the backlight illumination lamp (52) is turned on (step S2).

In this state, various operations before shooting are possible, but if a predetermined period of time elapses without any operations being performed, the switch (6
3) is turned off, and the lamp (52) is turned off (step 33.34).

In the next step S5, the shutter release key (4
2) is pushed to the first stage, the system control circuit (40
), the switch (63) is turned on, and the lamp (52) is turned on'' (step S6).

Thereby, the liquid crystal display element (51) of the viewfinder (50) is backlit by the lamp (52), and various operations before photographing, such as focus adjustment, can be smoothly performed.

Furthermore, when the shooting mode setting key (41) is pressed to change the shooting mode of shutter priority, aperture priority, program, or manual, the lamp (52) is turned on (steps S6 and S7). ), the shooting mode displayed on the liquid crystal display element (51) of the viewfinder (50) can be easily recognized.

In the next step S8, the shutter release key (
42) is pushed to the second stage, the electronic shutter is turned off and the optical shutter (13) is released.
Photographing is performed (step S9), and after photographing, the switch (6
3) is turned off, the lamp (52) is turned off (step 510), and backlight illumination power, which accounts for most of the power consumption of the viewfinder (50), is saved.

If the shutter release key (42) is not pressed to the second step and a predetermined period of time has elapsed, the switch (42)
63) is turned off and the lamp (52) is turned off (step 510.5ll), saving backlight illumination power.

In the above embodiment, the backlight illumination lamp (52) is turned on and off by turning on and off the control switch (63), but the lamp (52) may be dimmed by using an appropriate control element. .

[Effects of the Invention] As described in detail above, according to the present invention, in an electronic still camera equipped with a viewfinder having a backlit liquid crystal display, the viewfinder changes when changing the shooting mode and during shooting standby. Since the backlight is turned on only for a predetermined period of time, an electronic still camera can be obtained that can reduce power consumption of the viewfinder without impairing operability during still photography.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an embodiment of an electronic still camera according to the present invention, Fig. 2 is a flow chart for explaining the operation of an embodiment of the invention, and Fig. 3 is a block diagram showing the configuration of an embodiment of an electronic still camera according to the present invention. FIG. 4 is a block diagram showing an example of the configuration. FIG. 4 is a perspective view showing the configuration of main parts of a conventional example. (21) is a solid-state image sensor, (40) is a system control circuit (microcomputer), (41) is a shooting mode setting key, (42) is a shutter release key, (50) is an electronic viewfinder, and (51) is a liquid crystal display. Display element, (5
2) is a backlight illumination lamp, and (63) is a lighting control switch.

Claims (1)

[Claims] 1. An imaging means, a viewfinder having a liquid crystal image display means for displaying a video signal from the imaging means and a backlight illumination means, and an imaging drive circuit in two stages: a standby state and an operating state. an electronic still camera comprising a switch that can be set to An electronic still camera characterized in that: the backlight illumination means is turned on for a predetermined period, and the backlight illumination means is turned off or dimmed during the remaining period. 2. An electronic still camera comprising an imaging means, a switch for changing the imaging mode, and a viewfinder having a liquid crystal image display means and a backlight illumination means for displaying the video signal from the imaging means and the imaging mode. The lighting control means is provided to control the backlight illumination means, and when the switch is operated to change the imaging mode, the illumination control means turns on the backlight illumination means for a predetermined period of time, and the rest of the time. An electronic still camera characterized in that the backlight illumination means is turned off or dimmed during the period.