JP2531184B2 - Camera viewfinder - Google Patents

Description

The present invention relates to a viewfinder for a camera such as a VTR-integrated video camera or television camera.

[Outline of the Invention] The present invention relates to a viewfinder of a camera using a liquid crystal television monitor, in which a liquid crystal backlight illuminating device that can use external light as illumination light and an iris detection signal from an image pickup device are linked. Equipped with a control means for turning on / off or dimming the backlight illumination means, the outside light is used as the illumination light of the liquid crystal in a bright place such as outdoors, and the backlight is automatically illuminated in a dark place to provide a special detection mechanism. It is intended to reduce the power consumption of the backlight illumination of the liquid crystal at low cost without adding any additional components.

[Prior Art] Conventionally, a viewfinder is provided in a television camera or the like for a photographer to monitor a photographing state. Japanese Patent Application Laid-Open No. 56-160185 filed by the applicant of the present application proposes a viewfinder for a television which is colorized by using a monochrome cathode ray tube and a rotary color filter, but the cathode ray tube is housed. Due to the large space, in order to meet the recent demands for smaller size and lighter weight, LCD TV monitors, which are thin and have been colorized in recent years and whose performance has been remarkably improved, are about to be used in the viewfinder of cameras. Since LCD TV monitors do not emit light by themselves,
When it is necessary to apply external light or illumination light from a backlight from the outside, and it is considered to be used in a dark place like a viewfinder of a camera, the backlight system is adopted.

[Problems to be Solved by the Invention] However, in the viewfinder of the camera using the liquid crystal television monitor in the above-mentioned conventional technique, even when the camera is used in a bright place and the ambient light is sufficiently available for illumination of the liquid crystal. , It was not possible to save power because the liquid crystal backlight was always used. on the other hand,
In order to automate the illumination and save power, an external light detection mechanism is required, which may increase cost and run counter to the demand for smaller and lighter cameras.

The present invention was devised to solve the above problems, and an object of the present invention is to provide a viewfinder for a camera that saves power for liquid crystal backlight illumination without requiring a special detection mechanism. And

[Means for Solving the Problems] A viewfinder structure of a camera of the present invention for achieving the above object is a liquid crystal display in a camera viewfinder using a liquid crystal television monitor, in which external light can be used as illumination light. The backlight illumination means and the control means for turning on and off or dimming the backlight illumination means in association with the diaphragm detection signal from the image pickup device.

[Operation] In a camera such as a television camera, an image pickup element is built in, and external light around the subject is detected from the image pickup signal, and an aperture (iris) is controlled to adjust the brightness of the image. Therefore, since the diaphragm detection signal represents the brightness and darkness of the external light, the present invention uses the diaphragm detection signal to detect the backlight illumination means when the external light is sufficiently bright. Is turned off to use the external light as illumination light to save power, and only when it is not, the backlight illumination means is turned on for proof.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.
The present embodiment shows a case where it is applied to a video camera. The video camera includes an auto-focus or pan-focus lens 1, an aperture (hereinafter referred to as an iris) 2 that adjusts the brightness of an image, and an image sensor 3 such as a CCD (charge coupled device). The image pickup signal from the image pickup device 3 is adjusted to a video signal by the processing unit 4, and a detection signal IRISDET for the diaphragm that represents the aperture amount of the diaphragm according to the brightness around the subject is created. The iris drive circuit 5 drives the iris 2 based on this detection signal IRISDET,
The iris 2 is controlled to a predetermined opening amount, and the brightness of the image is adjusted to a predetermined value.

The viewfinder of this embodiment attached to this video camera is composed of a liquid crystal (LCD) television monitor 6, a backlight illumination means 7, a control means 8 for turning on and off the backlight illumination means 7, and the like. The backlight illumination means 7 includes a lamp 71 such as a fluorescent lamp, an optical conduit 72 that transmits external light and reflects the light of the lamp 71 to prove the liquid crystal television monitor 6, and a lamp power supply 73. The lamp 71 and the lamp power source 73 are connected via the control means 8 and turned on and off. The control means 8 compares the above-mentioned diaphragm detection signal IRISDET with a sampling pulse as an analog amount for a certain period of time, and a sample hold circuit 81. When the output level of the sample hold circuit 81 is compared with a predetermined value and exceeds a predetermined value, That is, it is composed of a switch circuit 82, etc., which is turned on when the opening amount is large because it is dark, and is turned off when it is less than that, that is, when the opening amount is small because it is bright. The lamp 71 described above is connected to the switch circuit 82. The sampling pulse of the sample hold circuit 81 may be provided from the processing unit 4 in addition to being created in the circuit. LCD TV monitor 6
A lens 9 is provided in front of, so that the photographer can view the LCD television monitor screen in an enlarged manner.

FIG. 2 is a perspective view showing the appearance of the video camera. The viewfinder case 11 is semi-fixedly rotatably attached to the upper portion of the video camera body 12 via a hinge 13, and is angled according to the image capturing posture. The viewfinder case 11 has an entrance window 11a for taking in outside light, and an optical conduit 72 is exposed. In addition, an eyecup 14 is attached to the eyepiece portion of the viewfinder case 11 to block external light entering the photographer's eyes, making it easier to see the LCD TV monitor screen. A lens barrel 15 that supports the lens 1 is attached to the front of the video camera body 12, and an iris 2 and an image sensor 3 are arranged on the optical axis thereof.
The handgrip 17 with the record button 16 is the video camera body.
Mounted under 12 and also cassette hold window 12
a is arranged on the side surface of the main body of the video camera 12.

FIG. 3 is a perspective view showing a configuration example inside the viewfinder case 11. The light conduit 72 is arranged on the back surface of the liquid crystal television monitor 6 via a light scattering plate 6a. The light conduit 72 has an opening at the bottom, and the lamp 71 is arranged in the opening. Further, the light pipe 72 transmits external light on the back surface,
A transparent or semi-transparent reflection part 72 capable of illuminating the liquid crystal television monitor 6 by reflecting the light of the lamp 71 from below.
It is provided with a and is exposed from the entrance window described above. This reflector 7
It is preferable to engrave a streak in the lateral direction on 2a in order to scatter the respective lights.
It is preferable to provide the reflection plate 74 so as to collect the light on the light spot.
A magnifying lens 9 is arranged in front of the liquid crystal television monitor 6.

FIGS. 4A and 4B are explanatory views of the operation of this embodiment. When the outside light is bright, the opening amount of the iris 2 is controlled to be small. That is, the aperture detection signal IRISDE
T is small. Therefore, the sample hold circuit 8 of FIG.
The output held at 1 also becomes small, it is determined that the outside light is sufficiently bright, and the switch circuit 82 in FIG. 1 is turned off.
As shown in (a), only external light is used for illumination of the liquid crystal television monitor 6 to save electric power. When the outside light is dark, the opening amount of the iris 2 is controlled to be large. That is, the diaphragm detection signal IRISDET is large. For this reason,
This time, the output of the sample hold circuit 81 also becomes large, it is determined that it is dark, and the switch circuit 82 of FIG. 1 is turned on.
As shown in (b), the lamp 71 is turned on to illuminate the liquid crystal.

In addition to the fluorescent lamp, other light sources can be used as the lamp. Although the lamp is turned on and off in the above-mentioned embodiment, it may be turned off when it is bright and dimmed so that when it is dark, the brightness is changed stepwise or steplessly according to the degree of darkness.

As described above, the present invention can be variously applied and embodied in accordance with its gist.

[Effects of the Invention] As is apparent from the above description, the viewfinder of the camera of the present invention has the following effects.

(1) Since the backlight is automatically turned off when it is bright, power is saved.

(2) Since a dedicated detection mechanism is not used for detecting the brightness of outside light, the cost does not increase so much, and the size and weight can be reduced while the liquid crystal is maintained.

[Brief description of drawings]

1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a perspective view of a video camera, FIG. 3 is a perspective view of a viewfinder, and FIGS. 4 (a) and 4 (b) are operation of the embodiment. FIG. 3 ... Image sensor, 6 ... LCD TV monitor, 7 ... Backlight illumination means, 8 ... Control means.

Claims (1)

(57) [Claims] 1. In a viewfinder of a camera using a liquid crystal television monitor, a liquid crystal backlight illuminating device that can use external light as illumination light, and the backlight illuminating device in association with a diaphragm detection signal from an image sensor. A viewfinder for a camera, comprising: a control means for turning on and off or dimming.