Television – Camera – system and detail – Swing driven
Reexamination Certificate
1998-08-26
2004-06-22
Garber, Wendy R. (Department: 2612)
Television
Camera, system and detail
Swing driven
C348S340000, C348S344000, C348S266000
Reexamination Certificate
active
06753906
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image sensing apparatus or an optical apparatus which enables to input a high quality image, by slightly changing the optical angle of a plane-parallel-plate glass or mirror provided in the optical path of an image sensing system.
Recently, as considerable progress has been made in image input apparatuses e.g., video cameras, scanners and the like, there are increasing demands for higher image quality and higher resolution in these apparatuses. However, increasing the number of pixels in an image sensing apparatus raises many problems, e.g., problems related to performance such as deteriorated sensitivity or reduced S/N ratio, high cost in manufacturing due to reduced yield, increased price in quartz crystal or low-pass filter or the like for preventing false signals or the like.
To cope with such problems, so-called “pixel-shifting” is known as a technique to achieve high quality and high resolution in an image sensing apparatus, without increasing the number of pixels of the image sensing device. Pixel-shifting enables to obtain a high-quality image substantially equivalent to a case of using an image sensing device having increased number of pixels. This is realized by providing a reflection mirror in the optical path within the optical relaying space between lenses and image sensing device and changing the reflection angle, or providing a plane parallel plate made of light-transmitting glass in the optical path and changing the angle of light incident upon the light-transmitting glass or the optical path length of the glass by making use of light refraction, or by slightly vibrating the image sensing device, thereby making it possible to guide optical image data, which was normally received by a light-insensitive zone between photoreceptive portions of the image sensing device, to the photosensitive portion and sequentially obtain the optical image data.
According to the pixel-shifting technique, a high quality image sensing can be performed without increasing the number of pixels of the image sensing device. Therefore, it is an extremely useful technique to realize higher resolution in image input apparatuses.
Examples of pixel-shifting utilizing the aforementioned principle are found in Japanese Patent Application Laid-Open No. 59-15378 where a plane parallel plate is rotated on an axis parallel to pixel array, or Japanese Patent Application Laid-Open No. 1-1218160 where a plane parallel plate surface is inclined and shifted in the optical-axis direction, or Japanese Utility Model Application Laid-Open No. 6-8937 where X and Y axes are provided and an inclination of plane parallel plate surface is changed by driving a cam with a motor.
However, the above-described conventional mechanism, utilizing a plane-parallel-plate glass, employs a motor as a driving source to change the optical position, and adopts a complicated and expensive mechanism, e.g., position control by cam. Because of this, it is difficult to ensure precision in positioning the plane-parallel-plate glass, and difficult to increase the driving speed.
Moreover, in addition to the necessity of a motor, a cam and a mechanism for transferring driving force of the motor, these mechanisms must be provided for horizontal and vertical directions. Naturally, the size of apparatus increases, and it becomes difficult to place the image-sensing apparatus in the space between lenses and image sensing device.
SUMMARY OF THE INVENTION
The present invention is made to solve the foregoing problems and has as its object to provide an image sensing apparatus or an optical apparatus comprising pixel-shifting system capable of high-speed driving in a simple structure.
In order to solve the above-described problems and attain the objects, the present invention provides an image sensing apparatus comprising: image sensing means for photoelectrically converting an optical image formed on an image sensing surface and outputting a sensed image signal; an optical device for shifting an incident position of light incident upon the image sensing surface of said image sensing means; a plurality of regulating members, abutting against a plurality of ends of said optical device, for regulating a position of each of the ends in respective optical axis directions, thereby controlling a first inclination angle of said optical device in a first direction with respect to an optical axis of said optical device and a second inclination angle of said optical device in a second direction which is perpendicular to the first direction; and optical device shifting means for shifting said optical device in order to have each of the plurality of ends of said optical device abut against each of said plurality of regulating members and holding each of the ends, wherein the incident position of light incident upon the image sensing surface is shifted in vertical direction of the image sensing surface by changing the first inclination angle of said optical device, and the incident position of light incident upon the image sensing surface is shifted in horizontal direction of the image sensing surface by changing the second inclination angle of said optical device.
According to the image sensing apparatus having the above construction, the optical device shifts an incident position incident upon an image sensing surface. An inclination position of both ends of the optical device with respect to the optical axis direction is regulated by a plurality of regulating members. Each of the regulating members abuts against each end of the optical device, thus making it possible to control the inclination position of the optical device in a plurality of directions. In other words, by having a simple structure where the optical device simply abuts against the regulating member, pixel-shifting operation can be performed at high precision.
According to an aspect of the present invention, it is preferable that the optical device is a plane parallel plate provided on an optical path of the image sensing means. When an inclination angle of said plane parallel plate with respect to the optical axis of said plane parallel plate is defined by said regulating members, the incident position of light incident upon the image sensing surface is shifted by an amount corresponding to the defined inclination angle.
It is preferable that each of the regulating members comprises regulating surfaces. Therefore, according to an aspect of the present invention, each of said regulating members comprises respective regulating surfaces, regulating surfaces provided for each of the ends of said optical device being formed at positions different from each other with respect to the front and back of the optical axis direction. The optical device can be controlled in a plurality of inclination angles by changing a combination of an end of said optical device and the regulating surface being abutted thereto.
Furthermore, according to an aspect of the present invention, said optical device has a shift range defined by a regulating surface, the shift range including a first shift range with respect to the optical axis direction of said optical device at one end of said optical device and a second shift range with respect to the optical axis direction of said optical device at the other end of said optical device, the first and second shift ranges having 1:1 relationship so that the inclination angle of said optical device can be equally divided between a maximum inclination position and a minimum inclination position.
Note that the end of the optical device and regulating surface contact each other by a line or point. Therefore, according to an aspect of the present invention, the first and second ends of said optical device, each of which abuts against a regulating surface of a regulating member, respectively include engaging portions each contacting the regulating surface of the corresponding regulating member by a line or point.
According to an aspect of the present invention, the engaging portion is a cylindrical member linearly
Canon Kabushiki Kaisha
Garber Wendy R.
Morgan & Finnegan , LLP
Villecco John M
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