JPH0750775A - Vtr incorporated type video camera - Google Patents

Abstract

PURPOSE:To provide a VTR incorporated type video camera capable of changing the brightness of a light for illumination corresponding to the brightness of an object and adjusting the brightness at an arbitrary level. CONSTITUTION:This camera is equipped with a digital processing circuit 5 which detects the brightness of the object, a PWM circuit 3 for light driving, and a microcomputer 4 which controls them, and changes the brightness of the light 1 for illumination by inputting a control signal in accordance with the brightness of the object to the PWM circuit 3 for light driving and changing a voltage to be applied to the light 1 for illumination. Also, the setting the brightness at the arbitrary level is performed by adjusting the brightness by changing a control voltage by a volume 6 mounted on a VTR incorporated type video camera main body. In this way, it is possible to automatically or intentionally change the brightness of the light 1 for illumination, which improves operability, and to attain power saving by preventing a power from being consumed wastefully.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The VTR integrated video camera is considered to be used under various conditions. In particular, when shooting in a dark place, the S / N ratio will decrease due to the characteristics of the camera.
Lighting is often used as an improvement. However, conventional illuminating lights merely provide a constant brightness.

According to the present invention, it is possible to change the brightness of an illuminating light according to the brightness of an object or adjust the brightness to an arbitrary brightness, which improves usability and uses more power than necessary for lighting. The present invention relates to a VTR-integrated video camera that can save power because it is not supplied to a light.

[0003]

2. Description of the Related Art As an example of controlling an illuminating light by utilizing the brightness of an object, there is a technique in which the illuminating light is turned on / off depending on the amount of incident light as disclosed in Japanese Patent Laid-Open No. 3-203472.

[0004]

The conventional technique merely controls ON / OFF of the light depending on the amount of incident light. Further, when the brightness of the illumination light is voltage-controlled by using an element such as a transistor, a problem of heat generation occurs.

An object of the present invention is to provide a VTR-integrated video camera capable of detecting the brightness of an object and providing the object with appropriate brightness or arbitrary brightness, thus improving usability and saving power. is there.

[0006]

The above-mentioned object is to generate a signal that gives an appropriate amount of illumination to a subject using a microcomputer or the like based on a video signal obtained by a CCD sensor or the like, and PWM type DC / D for driving
The voltage is applied to the C converter to change the voltage applied to the illumination light and the circuit is turned on. When the brightness is set to an arbitrary value, an arbitrary DC voltage is applied to the microcomputer by a volume provided on the video camera body to control it.

[0007]

The information of the brightness of the subject is taken in by the microcomputer, and the microcomputer calculates a voltage for lighting the illumination light, which is input to the light driving DC / DC converter and the voltage applied to the light is changed to change the brightness of the illumination light. To control.
In this case, the brightness of the illumination light is changed according to the brightness of the subject, but when the same subject is continuously shot, the brightness of the illumination light remains constant even if the brightness of the subject changes slightly. Leave. This is to prevent the brightness of the illumination light from fluctuating too much and the captured image from becoming unnatural. Extremely change the brightness of the illumination light only when it is panning. These processes are performed by the software of the microcomputer.

[0008]

FIG. 1 shows an example of a circuit using the present invention. The object information is converted into a video signal by the sensor drive circuit and A /
Digitized by D converter. The digital signal processing circuit 5 detects the brightness of the subject, and the microcomputer 4 performs arithmetic processing to control the brightness of the illumination light. The light brightness information signal is input to the light driving PWM circuit 3 to generate a DC voltage for lighting the light.

Further, the microcomputer 4 is also supplied with an ON / OFF switch for the light, an automatic switch for automatically turning on the light according to the brightness of the object, a manual switching signal for arbitrarily adjusting the brightness, and a level adjustment signal for the manual mode. To do.

FIG. 2 shows an example of a write driving PWM circuit. The basic circuit is a step-down chopper circuit. The light brightness control signal is input to the DC / DC converter control IC 7 to generate a signal having a pulse width corresponding to the control signal to switch the transistor 8 and convert it into a DC voltage by the flywheel diode 9 and the smoothing circuit 10 to turn on the light 1. Let

The switching waveforms are shown in FIG. The light driving PW is such that the duty of the pulse width is widened when the illumination light is turned on brightly and narrowed when the illumination light is darkened.
Configure the M circuit.

The relationship between the write applied voltage VL and the write brightness control voltage VC is shown in equation 1. As can be seen from this equation, the two have a proportional relationship, and the inclination is the feedback resistance Ra.
11a and Rb 11b. This graph is shown in FIG.

[0013]

[Equation 1]

[0014]

According to the present invention, there is provided a VTR-integrated video camera capable of changing the amount of light of an illumination light according to the brightness of a subject or adjusting the brightness to any brightness.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

FIG. 2 is a PWM circuit diagram for driving a light.

FIG. 3 is a switching waveform diagram when a light is turned on.

FIG. 4 is a diagram showing a relationship between a light brightness control signal and a light applied voltage.

[Explanation of symbols]

 1 ... Lighting light, 2 ... Battery, 3 ... Light driving PWM circuit, 4 ... Microcomputer, 5 ... Digital signal processing circuit, 6 ... Manual level adjusting volume, 7 ... DC / DC converter control IC, 8 ... Transistor, 9 ... flywheel diode, 10 ... smoothing circuit, 11a ... feedback resistance Ra, 11b ... feedback resistance Rb.

Claims (1)

[Claims] 1. When photographing a dark place such as indoors or at night, the amount of light becomes insufficient, so when the illumination light is attached as an auxiliary illumination means, the brightness of the illumination light is adjusted by the camera image and any adjustment. VTR integrated video camera characterized by changing.