JPS6367877A - Video camera - Google Patents

Abstract

PURPOSE:To simplify structure by making a mechanical diaphragm device unncessary, and to reduce power consumption, by detecting a light quantity from an object, and controlling the charge accumulating time of a solid-state image pickup element variably. CONSTITUTION:The image of the object by a photographing lens 2 is image- formed on the solid-state image pickup element 3, and the solid-state image pickup element 3 is constituted so that the charge accumulating time can be changed arbitrarily by a control circuit 10. A signal from the solid-state image pickup element 3 is supplied to a signal processing circuit 4, and is converted to a prescribed video signal. The brightness of the object is detected by a light quantity detecting element 11 arranged in the neighborhood of the lens 2, for example, a photodiode, and a light quantity detection circuit 12, and the charge accumulating time of the solid-state image pickup element 3 is controlled by the control circuit 12 so as to make better the contrast of a photographing image, based on the signal corresponding to the brightness of the object from the light quantity detection circuit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a video camera that can be used in combination with a portable video tape recorder or the like.

2. Description of the Related Art A conventional video camera will be described below with reference to the drawings. FIG. 2 is a diagram showing the main parts of a conventional video camera, in which a lens 2 for photographing a subject and an aperture 7 for adjusting the amount of light are arranged at the front of a video camera body 1. As is well known, the diaphragm 7 changes the aperture area through which the amount of light passes by rotating several blades tI (not shown) by an electromagnetic actuator 8 such as a galvanometer. The image taken by the photographing lens 2 is formed on the image sensor 3.

The signal from the imaging element 3 is supplied to a signal processing circuit 4 and converted into a predetermined video signal. This video signal is supplied to an electronic viewfinder 5 for checking the photographed image and a video output terminal 6 for recording to a baud pull video tape recorder (not shown). Furthermore, by taking advantage of the fact that the output of the image sensor 3 changes depending on the amount of photographing light, the electromagnetic actuator 8 of the diaphragm 7 is controlled by the signal from the signal processing circuit 4, and the light amount is automatically adjusted so that the amount of photographing light is appropriate. ing.

However, in the above configuration, the aperture 7 and the electromagnetic actuator 8 are required, so the structure is complicated.
There are problems in that it consumes a lot of power and is expensive.

In view of the above problems, the present invention provides a video camera that eliminates the mechanical aperture of the conventional video camera, has a simple structure, consumes less power, and is inexpensive.

Means for Solving the Problems In order to solve the above problems, the video camera of the present invention
a photographic lens for photographing a subject; a solid-state image sensor for converting an optical image from the photographic lens into an electrical signal; a light amount detection means for detecting the amount of light from the subject; This device includes a control means that variably controls the charge accumulation time of the image sensor.

Operation The present invention eliminates the need for the conventional mechanical throttle due to the above-described configuration, and therefore has a simple structure, consumes less power, and can be manufactured at low cost.

Embodiment Hereinafter, a video camera according to an embodiment of the present invention will be described with reference to the drawings.

1 is a diagram showing a main part configuration of a video camera according to an embodiment of the present invention shown in FIG. 1. FIG.

A lens 2 for photographing a subject is arranged at the front of the video camera body 1. An image formed by this lens 2 is formed on a solid-state photographing element 3. This solid-state (B detection element 3) is configured such that the charge accumulation time can be changed arbitrarily by a control circuit 10 as shown in Japanese Patent Laid-Open No. 60-5681. The signal from the solid-state image sensor 3 is The signal is supplied to a signal processing circuit 4 and converted into a predetermined video signal.This video signal is supplied to an electronic viewfinder 5 for checking the captured image and a video output terminal 6 for recording on a VTR.

The brightness of the object is detected by a light amount detection element 11 such as a photodiode and a light amount detection circuit 12 arranged near the lens 2.

The solid-state image sensor 3 is controlled by the control circuit 10 described above in response to a signal corresponding to the brightness of the object from the light amount detection circuit 12.
The charge accumulation time is controlled so that the contrast of the photographed image is good. Furthermore, a knob 13 provided on the outside of the video camera body 1 can also be used via the control circuit 10.
This allows the charge accumulation time to be controlled so that the contrast of the captured image can be adjusted as desired.

As described above, according to the present embodiment, there is provided a photographic lens for photographing a subject, a solid-state image sensor for converting an optical image from the photographic lens into an electrical signal, a light quantity detection means for detecting the quantity of light from the subject, and a light quantity detecting means for detecting the quantity of light from the subject. By providing a control means for variably controlling the charge accumulation time of the solid-state image pickup device according to a signal from a detection means, a remarkable effect can be obtained in that a conventional mechanical aperture device is not required. It is something that can be done.

In addition, in the above explanation, the brightness of the subject is measured by the light amount detection element 1.
1. Although the light amount detection circuit 12 is used to detect the brightness of the object, it is also possible to detect the brightness of the object using the video signal from the solid-state image sensor 3, and to operate the control circuit according to the brightness signal of the object based on this video signal. It is also possible to control the charge accumulation time of the solid-state image sensor 3.

Effects of the Invention As described above, the present invention comprises a photographing lens for photographing a subject, a solid-state i-imaging element for converting an optical image from the photographing lens into an electrical signal, and a light amount detection means for detecting the amount of light from the subject. , a control means for variably controlling the charge accumulation time of the solid-state image pickup device according to the signal from the light amount detection means, thereby making it possible to eliminate the need for a mechanical aperture device, resulting in a simple structure. , low power consumption,
Moreover, it can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts in an embodiment of the present invention, and FIG. 2 is a block diagram of main parts of a conventional video camera. 2...lens, 3...solid-state image sensor,
10... Control '+11 circuit, 11... Light amount detection element, 12... Light amount detection circuit, 13...
...Knob. Name of agent Patent attorney Toshio Nakao Baka 1 No. 1 [2
1 Figure 2

Claims (1)

[Claims] a photographic lens for photographing a subject; a solid-state image sensor for exchanging an optical image from the photographic lens into an electrical signal; a light amount detection means for detecting the amount of light from the subject; A video camera comprising: a control means for variably controlling charge accumulation time of an image sensor.