JPS60149269A - Television camera - Google Patents

Abstract

PURPOSE:To increase the apparent number of arrays and to output a video signa l of high image resolution by providing an optical prism to a TV camera to shift the position of a subject forming its image on an array surface of an image pickup element through vibrating synchronously with the vertical synchronizing signal of a video signal. CONSTITUTION:A subject image supplied through a lens of a TV camera is applied to optical prisms 2a and 2b and forms an image on an array surface of a solid state image pickup element 3 through both prisms. These prisms 2a and 2b has the same form, and the output surface of the prism 2a and the incident surface of the prism 2b are set vertical to the optical axis. Then piezoelectric elements 7a and 7b are attached to said both surfaces. The drive pulses are applied to both elements 7a and 7b from a prism driving circuit 5 to vibrate prisms 2a and 2b up and down. Both the circuit 5 and the element 3 are actuated synchronously with each other with the output of a synchronizing signal generator 6. Thus the apparent number of arrays is increased for the element 3, and the video signals of high image resolution are outputted from a process circuit 4.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a television camera using a solid-state image sensor capable of obtaining high-resolution video signals.

Conventional structure and its problems Conventionally, in order to convert a subject image into a video signal using a solid-state image sensor, the subject image is formed on the solid-state image sensor by the optical system of a television camera, and A video signal is obtained by extracting the amount of light on the array of image sensors in time series. The resolution of the video signal is determined by the total number of arrays; for example, when using a COD with approximately 400 pixels in the horizontal direction, the horizontal transfer lock frequency is approximately 7.2 MHz, and the horizontal resolution is 280T.
Only about V pieces can be obtained. If an attempt is made to obtain a resolution higher than that, aliasing distortion due to sampling will appear in the video signal, severely degrading the image quality. For this reason, 1. In order to obtain high-resolution images in a television camera using solid-state image sensors, there is a drawback that the number of arrays of solid-state image sensors must be increased.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a television camera that eliminates the drawbacks of the prior art described above and that can obtain high-resolution video signals without increasing the number of arrays of solid-state image sensors.

Structure of the Invention The present invention is a television camera in which the optical axis is adjusted by controlling the thickness of two optical prisms arranged between a lens and an imaging surface of a solid-state imaging device in synchronization with a vertical synchronization signal of a video signal. By moving the optical axis and focusing the object image, which was conventionally focused in the gap between the arrays in solid-state imaging devices, on the array, the total number of apparent arrays can be increased, and high-resolution video signals can be generated. It is to obtain.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. Figure 1 shows
FIG. 2 is a block diagram of a circuit that controls an optical prism that is arranged in an optical system in a television camera and changes the imaging position on a solid-state image sensor. In Figure 1, 1 is a lens, 2
a, 2b are optical prisms, 3 is a solid-state image sensor, 4 is a process circuit, 5 is a prism drive circuit, and 6 is a synchronization signal generator.

In FIG. 1, a subject image incident through a lens 1 is formed on the array surface of a solid-state image sensor 3 through optical prisms 2a and 2b, and this optical image is converted into a time-series electric signal by the solid-state image sensor and then processed. Supplied to circuit 4. The process circuit 4 performs predetermined signal processing on the signal from the image sensor, converts it into a video signal, and sends it out. The prism drive circuit 6 forms a prism drive pulse synchronized with the vertical synchronization signal supplied from the synchronization signal generator 6, and vibrates the optical prisms using piezoelectric elements attached to the optical prisms 2a and 2b.

FIG. 2 shows a drawing of the optical prism. optical prism 2a
, 2b have the same shape, the output light surface of the optical prism 2a and the input light surface of the optical prism 2b are perpendicular to the optical axis, and the two optical prisms are arranged in close contact with each other. Piezoelectric elements 7a and 7b are attached to the end faces of the optical prisms 2a and 2b facing the apex angles, respectively, and the piezoelectric elements are driven by drive pulses from the prism drive circuit 5 shown in FIG. 1 to drive the optical prisms. 2a.

2b is vibrated in the vertical direction in FIG.

In FIG. 2a, the optical prisms 2a and 2b are piezoelectric elements 7a and y.
The figure shows the state when the thickness dl of the two optical prisms is the thickest when driven by the lens b, and the light l incident from the lens enters the optical prism 2a and is reflected by the difference in refractive index between the air and the optical prism. The angle σ with respect to the optical axis is refracted by
1 and travel straight through the optical prisms 2a and 2b. When the light is emitted from the optical prism 2b, it is refracted at an angle to the optical axis due to the difference in refractive index between the optical prism 2b and the air, and travels straight toward the imaging surface of the solid-state image sensor.

Assuming that the refractive index of the optical prisms 2a and 2b is nl and the refractive index of air is no, the relationship between the incident light and the refracted light at the entrance surface of the optical prism 2a is no Sjnθ1=: n1sinσ1...
・・・・・・・・・・・・(1) However, θ... Angle between the incident light and the incident light surface α... Expressed as the angle between the refracted light and the incident light surface .

Similarly, the relationship when emitting light from the optical prism 2b is n1'sinσ2=no'Slnθ2...
...It is expressed as (2).

In the above formulas (1) and (2), n. -”O’”1
= "1", and since the entrance surface of the first optical prism and the exit surface of the second optical prism are parallel, σ1=
a2θ1-θ2, and the light incident on the optical prism 2a and the optical axis emitted from the optical prism 2b are parallel, resulting in light whose optical axis has been moved by vl in the vertical direction.

This vertical movement distance v1 is expressed by the following formula, where
dl...Thickness θ of the optical prisms 2a, 2b...Angle between the incident light surface of the optical prism 2a and the refracted light As shown in the equation, the optical prisms 2a, 2b have an angle between the air and the refracted light. Due to the difference in refractive index with optical glass, the optical axis of the subject image can be
The function is to move only 1.

As in FIG. 2, a driving pulse synchronized with the vertical synchronization signal is applied to the optical prisms 2a and 2b, and the optical prisms 7b...
··Piezoelectric element.

Claims (1)

[Claims] In the optical path of the solid-state image sensor, two optical prisms each having an entrance light surface and an exit light surface tilted with respect to the optical axis are arranged such that the entrance light surface of the first optical prism, the exit light surface of the second optical prism, and the exit light surface of the first optical prism are arranged. The exit light surface of the first optical prism and the entrance light surface of the second optical prism are arranged so as to be parallel to each other, and A television camera characterized in that the second optical prism vibrates in synchronization with a vertical synchronization signal of a solid-state image sensor, and changes its thickness in the optical axis direction.・