JPH03131188A - Image pickup device - Google Patents

Abstract

PURPOSE:To attain registration adjustment with high accuracy easily and quickly by arranging a lens element movable on an optical axis in front of an image pickup element on an optical axis and moving the lens element on the optical axis by a drive motor based on an output signal from a video evaluation circuit. CONSTITUTION:A video signal obtained from an image pickup element 16 via a connector cable 18 is evaluated by a video evaluation circuit 101. Then the position and the direction or the like of a lens element 21 when object images in a prescribed color light formed on image pickup elements are coincident with each other are evaluated and an evaluation signal obtained in this case is sent to a drive control circuit 19. Then the drive control circuit 19 drives a motor 32. The drive of the motor 32 drives a micrometer 10 via gears 31, 33. A moving base 12 is moved by a frame 11 in contact with the tip of the micrometer 10. Thus, the lens element 21 provided with respect to the moving base 12 is adjusted in the optical axis direction.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to an imaging device used in a color television camera, etc., and in particular to adjustment of registration of the color television camera when a solid-state image sensor is used as an imaging means. The present invention relates to an imaging device that performs well.

(Prior art) Conventionally, in color television cameras, the light flux from the photographing lens is separated into multiple colors of light, such as red, green, etc., using a color separation prism.
The light is separated into three colors of blue, and an object image based on each color is formed on the surface of the image sensor. Color reproduction is then performed by obtaining color video signals from each image sensor. Each of these three color lights has a predetermined center (fundamental) wavelength, so due to the influence of the lateral chromatic aberration of the photographing lens, the sizes of the three object images based on each color light do not match and shift from each other, resulting in a registration error. It's coming.

Furthermore, in color television cameras, a zoom lens is generally used as a photographing lens. With zoom lenses, lateral chromatic aberration changes depending on the zoom position due to zooming, so 3.
The size of the object image of colored light also varies depending on the zoom position, which appears as a registration error.

In a conventional imaging device using an imaging tube, the deflection of an electron beam is electrically controlled to correct lateral chromatic aberration of a photographic lens and perform registration correction.

(Problem to be solved by the invention) However, when using solid-state image sensors, which have been rapidly put into practical use in recent years, the arrangement of the elements is determined geometrically, so registration correction is not possible as in the past. The problem was that it couldn't be done.

Therefore, when you change the shooting lens or change the magnification with a zoom lens, etc., the effect of the lateral chromatic aberration of the shooting lens or zoom lens will appear on the screen as it is, and the object image of each color light will shift around the periphery of the screen. The problem of distorted images was resolved.

For this reason, in conventional imaging devices that target solid-state image sensors, it is necessary to better correct lateral chromatic aberration in the imaging system. For example, it is necessary to use a glass material with high anomalous partial dispersion in the imaging system, There was a problem in that the number of components had to be increased.

When the present invention configures an imaging device using a solid-state image sensor, a lens element having a predetermined refractive power is arranged in front of the solid-state image sensor on the optical axis, and the lens element is driven by an appropriately configured driving means. By moving in the direction of the optical axis,
Moreover, it is an object of the present invention to provide an imaging device that allows quick registration adjustment.

(Means for Solving the Problems) The imaging device of the present invention is an imaging device that separates a luminous flux from a photographing lens into a plurality of colored luminous fluxes through a color separation optical system, and then guides the light to each imaging element. , correcting the chromatic aberration of magnification of the photographic lens in front of at least one image sensor P of the plurality of image sensors on the optical axis to substantially match the sizes of object images formed on each image sensor. A lens element that is movable on the optical axis and has a refractive power that allows for It is characterized by providing a driving means for electrically moving the optical axis.

(Embodiment) FIG. 1 is a schematic view of a main part of an embodiment in which the present invention is applied to a color television camera, and FIG. 2 is a detailed view of a portion of FIG. 1 viewed from B.

In the figure, reference numeral 1 denotes a photographing lens, which is composed of, for example, a zoom lens. 2 is a filter member for near-infrared cut and color temperature conversion, 3 is a color separation prism, and photographing lens 1
The luminous flux from the sensor is separated into, for example, three colored lights: red, green, and blue. 4a.

Reference numerals 4b and 4c are registration adjustment mechanism sections provided independently, and one of the registration adjustment mechanism sections has a lens element 21 as shown in FIG. Registration adjustment is performed by moving in the optical axis direction using a predetermined driving means. Reference numeral 5 denotes an optical base on which the color separation prism 3 and registration adjustment mechanism sections 4a, 4b, and 4c are mounted. 6 is a camera base on which optical members such as a field lens, a relay lens, and a filter are fixed.

In this embodiment, an object image formed by a photographing lens 1 is separated into three colored object images by a color separation prism 3 via a filter member 2, and the images are formed on each image sensor surface. Then, convert the object image based on each color light into an electrical signal,
After signal processing, etc., a color image is obtained.

Next, FIG. 2 shows a case where registration adjustment is performed by moving the lens element 21 on the optical axis.

A pedestal 7 supports the prism unit 102. 8 is a registration adjustment mechanism section 4a (4b, 4
c) is the fixed base. Reference numeral 10 denotes a micrometer, which is rotated by a drive means to be described later to move a movable base 12 to be described later in the optical axis direction. 9 is a micro support plate, which supports the micrometer 10. 11 is a top, which is in contact with the tip of the micrometer 10.

12 is a movable base to which the top 11 is attached, and 13 is a linear bearing, which is provided between the fixed base 8 and the movable base 12, and allows the movable base 12 to move smoothly.

31 is a gear, which is fixed to the micrometer 10. 32 is a motor. A gear 33 is attached to the motor 32 and transmits rotational force from the motor 32 to the gear 31.

21 is a lens element, which will be described later. It has a refractive power that can correct the chromatic aberration of magnification of the two lenses 1 and substantially match the sizes of object images of each color light formed on each image sensor. 22 is a lens element support plate, which holds the lens element 21.

16 is an image sensor such as a CCD, and 17 is a printed circuit board, which is connected to the image sensor 16. A connector cable 18 is connected to the printed circuit board 17. 1
9 is a drive control circuit, which includes a video evaluation circuit 101 to be described later.
The movable base 12 is moved along the optical axis by driving the motor 32 based on a signal from the optical axis.

The motor 32 and the drive control circuit 19 constitute one element of the drive means.

Note that a spring (
(not shown) is provided so that the tip of the micrometer 10 is always in contact with the top 11.

101 is a video evaluation circuit, and a connector cable 18
A video signal obtained from the image sensor 16 via the image sensor 16, for example, a video signal related to the size of an object image, is evaluated, and the evaluation signal is transmitted to the drive control circuit 19.

In this embodiment, the video signal obtained from the image sensor 16 via the connector cable 18 is evaluated by the video evaluation circuit 101, and the lens element 21 is evaluated so that the object images of predetermined color light formed on the surface of each image sensor coincide with each other. The position, direction, etc. are evaluated, and the evaluation signal at this time is transmitted to the drive control circuit 19. Then, the motor 32 is controlled by the drive control circuit 19.
drive.

The rotation of motor 32 rotates micrometer 10 via gears 31,33. The rotation of the micrometer 10 at this time causes its tip to move linearly in the optical axis direction, and the movable base 12 is moved by the top 11 in contact with the tip of the micrometer 10. Thereby, the optical axis direction of the lens element 21 provided with respect to the movable base 12 is adjusted.

As described above, in this embodiment, the driving means is used to move the fixed lens element 21 with respect to the movable base 12 along the optical axis, and to adjust the imaging magnification of the object image, that is, to properly adjust the registration. ing.

In this embodiment, the movement of the image plane due to the movement of the lens element is small, and in most cases it is within the depth of focus and can be ignored.

In this embodiment, each registration adjustment mechanism section can be adjusted independently, thereby enabling highly accurate registration adjustment.

Also, tl! ! When a zoom lens is used as the second system, information on lateral chromatic aberration that changes as the magnification changes is stored in the storage section, and after registration adjustment at a predetermined zoom position - degree, the information on the lateral chromatic aberration that changes as the zoom is changed is stored based on the information from the storage section. Registration adjustment may also be performed by electrically moving the image sensor along the optical axis following the magnification change.

(Effects of the Invention) According to the present invention, a lens element provided on the optical axis in front of the image sensor or behind the exit surface of the color separation prism is electrically moved onto the optical axis using a driving means having the configuration described above. To achieve an imaging device suitable for a color television camera, etc., in which registration adjustment can be performed easily, quickly, and with high precision by moving the device, and in which the adverse effects of lateral chromatic aberration of a photographing system are effectively prevented. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a schematic view of a main part of an embodiment in which the present invention is applied to a color television camera, and FIG. 2 is a detailed view of a portion of FIG. 1 viewed from B. In the figure, 1 is a photographing lens, 2 is a filter member, 3 is a color separation prism, 4a, 4b, 4c are registration adjustment mechanism parts, 5 is an optical base, 6 is a camera base, 7 is a pedestal,
8 is a fixed base, 9 is a micrometer support plate, 10 is a micrometer 11 is a top, 12 is a movable base, 13 is a linear bearing, 15 is an image sensor support plate, 16 is an image sensor, 21 is a lens element, 22 31. is a lens element support plate;
33 is a gear, 32 is a motor, 19 is a drive control circuit, 1
01 is a video evaluation circuit. Minekuni

Claims (2)

[Claims] (1) In an imaging device that separates a light beam from a photographic lens into a plurality of colored light beams via a color separation optical system and then guides the light to each image sensor, at least one of the plurality of image sensors In front of P on the optical axis is a lens element movable on the optical axis that has a refractive power capable of correcting the chromatic aberration of magnification of the photographing lens and substantially matching the size of object images formed on each image sensor. and a drive means for evaluating the video signal from the image sensor P with a video evaluation circuit and electrically moving the lens element along the optical axis based on the output signal from the video evaluation circuit. An imaging device characterized by: (2) The imaging device according to claim 1, wherein the driving means utilizes a motor.