Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Reexamination Certificate
2000-03-10
2002-08-20
Kim, Robert H. (Department: 2882)
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
C348S308000, C348S315000, C257S290000, C257S291000
Reexamination Certificate
active
06437307
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image sensor having a light-sensitive surface, nonlight-sensitive circuit section, and a wiring section for connecting the circuit section, and wiring section.
2. Discussion of the Background Information
To record still or moving images in video technology, two main methods have become established in the past few years, photodiode arrays and CCD sensors. Currently, over 90% of all sensors that are used are CCD technology.
The photodiode array is the older technology, but in its original form it had several technologically-caused disadvantages that led to lower sensitivity, higher noises, lower speed, etc., which is why it has been displaced by the CCD sensors for the most part.
However, CCD sensors have the disadvantage that, due to the additional complexity of the manufacturing process and the increased manufacturing costs, they cannot easily be integrated with CMOS circuits. In addition, CCD sensors are high-capacity devices, so that on-chip CMOS driver electronics for large-surface assemblies would require very high power (2 to 3 W). Moreover, many different voltage levels are required for CCD sensors in order to ensure high efficiency of the charge transfer.
In contrast, progress in silicon technology has made it possible, in a photodiode array, to add a separate active processing unit (e.g., amplifier, etc.) to each image recording member, thereby eliminating the existing disadvantages of the photodiode arrays and, in particular, even creating new capabilities for image recording. This is known as “APS” (“active pixel sensor”) technology. APS technology is currently considered to be very significant technologically for the future.
Improvements have been made to the known systems to increase image sharpness and resolution so that a sharp image with good resolution and high contrast can be represented with a predetermined number of image members. In that regard, it has been observed that a hexagonal arrangement of sexangular members, as also present in the retina of humans and animals, is also very advantageous. However, such an arrangement is linked to the problem that digital image processing is obviously hampered, because the individual image sensor members are not arranged in an assembly of columns and rows.
However, with regard to optimizing the assembly of image sensor members, the known CCD sensors have the disadvantage that CCD technology offers very little freedom with regard to the shape and arrangement of the pixels. In practice, only rectangular shapes of image sensor members, which are combined into a regular Cartesian matrix, are of importance.
In U.S. Pat. No. 3,971,065, an image sensor is described in which three different types of image sensor members, each consisting of CCD sensors, are arranged in such a way that the same types of image sensor members are arranged in the form of grids. More specifically, the various types of image sensor members each represent a first color, for example, green, a second color, for example, red, and the general brightness. The image sensor members for general brightness are disposed in a checkerboard pattern, while the image sensor members for the first color fill up the intermediate spaces in a first checkerboard pattern row, the image sensor members for the second color fill up the intermediate spaces in the second checkerboard pattern row, and so on. This is intended, on the one hand, to avoid the high complexity of the optical design and, on the other hand, to avoid the problems related to the conventional process of image position accuracy when using filters for different colors disposed behind one another.
Compared to the CCD sensors, when using APS-CMOS sensors in principle almost any chosen form with any chosen overall arrangement is feasible.
In a known AP sensor, as known, for example, from “CMOS Active Pixel Image Sensors for Highly Integrated Imaging Systems,” Sunetra K. Mendis et al., IEEE Journal of Solid-State Circuits, Vol. 32 No. Feb. 2, 1997, or “Smar Image Sensors for Optical Microsystems,” Peter Seitz, et al., Laser und Optoelectronik 28(6)/1996, an individual sensor member substantially comprises three components, which are disposed as shown in
FIG. 4
a:
1. A light-sensitive surface
101
in the form of a photodiode or a phototransistor
2. A circuit section
100
which, for example, includes multiple CMOS transistors and is generally not used for light sensors, to generate a signal corresponding to the incident light and processing of the signal
3. A wiring section
102
which connects the individual sensor image members to an overall sensor
The arrangement of the components of the individual sensor members is determined according to switching and layout requirements and is not necessarily optimal for later additional processing of the image information. The sensor members are then arranged according to
FIG. 4
b
into a matrix or other structures.
When optimizing the known image sensor members and image sensors, one skilled in the art will find himself in the field of tension of the following contradictory trends.
1. On the one hand, image sharpness and resolution can be improved by increasing the number of image sensors and enlarging the ratio of light-sensitive surface to image sensor surface.
2. On the other hand, the cost and speed of the resulting image sensor depend on the number of sensor members. In other words, the greater the number of sensor members, the slower and more expensive the resulting image sensor becomes.
SUMMARY OF THE INVENTION
An aspect of the present invention is therefore to improve the known image sensor member and the known assembly of image sensor members in such a way that the costs of the image sensor resulting from the image sensor members is reduced, its speed is increased, and, simultaneously, the image sharpness and resolution of the image sensor are not impaired.
According to an aspect of the present invention, an assembly of image sensor members is provided for line or column-wise recording of images, each having a light-sensitive surface; and a circuit section which in addition has a wiring section for connecting the individual circuit sections to one another and to the outside, in which the circuit section and the wiring section each occupy one part of the surface of the image sensor member characterized in that each center of gravity (centerpoints) of the light-sensitive surfaces of the individual image sensor members is disposed in the form of at least two square grids which are offset relative to one another, while the lines of the square grids are each parallel to the lines or columns of the image to be recorded.
According to a further aspect of the present invention, an assembly of image sensors members is provided wherein the light sensitive surface is disposed on one half of the image sensor member. According to a still further aspect of the present invention, the image sensors are used in a high-speed camera.
According to an aspect of the present invention, a rectangular image sensor member with a predetermined length and width is provided, the rectangular image sensor member including a light sensitive surface; a circuit section; a wiring section for connecting said circuit section to an external circuit; a first surface portion in which the circuit section and wiring section are arranged; and the light sensitive surface being arranged outside of said first surface portion.
According to another aspect of the present invention, the light-sensitive surface substantially covers the predetermined width. Additionally, other aspects of the present invention includes an image sensor member having a length to width ratio of about 2:1, 3:1, or 4:1. In another aspect of the present invention the light-sensitive surface is formed as one of a square, rectangle, hexagon, and circle.
According to a further aspect of the present invention, the light-sensitive surface is disposed on about one half of the image sensor member. In another aspect of the present invention, the light-
Bloss Hans
Möller Heino
Fraunhofer-Gesellschaft zur Forderung zur Angewandten Forshung e
Greenblum & Bernstein P.L.C.
Kim Robert H.
Thomas Courtney
LandOfFree
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