Television – Camera – system and detail – Optics
Reexamination Certificate
1996-04-17
2002-05-14
Garber, Wendy R. (Department: 2612)
Television
Camera, system and detail
Optics
C348S340000
Reexamination Certificate
active
06388709
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image sensing apparatus and, more particularly, to an image sensing apparatus capable of increasing quality of an image obtained from a solid-state image sensing device by equipping the image sensing apparatus with a solid-state image sensing device and optical modulation means which has controllable wavelength transmission selectivity characteristics and/or controllable light transmission characteristics.
Variety of image sensing system, such as an electronic still camera, a video camera and a TV conference camera, for obtaining image information by sampling an object by using a solid-state image sensing device have been developed and widely used. A conventional image sensing optical system using a solid-state image sensing device will be described below.
FIG. 44
is a cross-sectional view of an image sensing optical unit using a common solid-state image sensing device used in a video camera and the like, and an optical axis. In
FIG. 44
, reference numeral
1
denotes an image sensing optical system which includes lenses
1
a
and an iris diaphragm
1
b.
Reference numeral
2
denotes a filter for adjusting a quantity of incoming light to a solid-state image sensing device
3
or for cutting high spatial frequency included in the object, and reference numeral
13
denotes the optical axis of the image sensing optical system
1
.
Light from the object passes through the lens
1
a
of the image sensing optical system
1
and the filter
2
, then forms an image on a photo-sensing surface of the solid-state image sensing device
3
.
Next, how the light from the object formed on the solid-state image sensing device
3
as the image is photoelectric-converted in the solid-state image sensing device
3
will be explained.
FIG. 45
is a cross-sectional view of a part of the generally used solid-state image sensing device
3
for color image sensing. In
FIG. 45
, the same reference numerals as in
FIG. 44
denote elements having the same functions, and explanation of these elements are omitted. In
In
FIG. 45
, reference numeral
4
denotes a color filter formed on the solid-state image sensing device
3
;
5
, an on-chip lens;
6
, light blocking unit;
7
, a photoelectric converter;
8
, parts each of which corresponds to each pixel of the solid-state image sensing device
3
; and
16
, an image sensor controller for controlling the solid-state image sensing device
3
.
The on-chip lens
5
is attached to the solid-state image sensing device
3
, for increasing aperture rate. The color filter
4
is configured so that areas corresponding to respective pixels have different spectral transmittances which transmit red, blue, and green light, for instance, per pixel, and provided in the solid-state image sensing device
3
in order to selectively extract colors of the light from the object.
The light from the object which forms the image on the solid-state image sensing device
3
consisting of a plurality of pixels passes through the on-chip lens
5
and color filter
4
, then reaches each pixel of the photoelectric converter
7
. Then, the light is photoelectric-converted by the photoelectric converter
7
, and stored in a form of electric charge in each pixel. The electric charge stored in each pixel is periodically sent to a charge transfer unit (not shown) under the control of the image sensor controller
16
. Thereafter, the image of the object is generated by image generating means (not shown) on the basis of the transferred charge.
A solid-state image sensing device for sensing a color image is shown in FIG.
45
. Although it is not shown, there are a solid-state image sensing device for a black-and-white or monochromatic image which is not provided with the color filter
4
, and a solid-state image sensing device to which the on-chip lens
5
for increasing aperture rate is not attached.
The solid-state image sensing device
3
as described above is manufactured in such a manner that parts, such as a transfer unit (not shown) and the photoelectric converter
7
, are sequentially formed during a semiconductor manufacturing process
Further, the color filter
4
used for color image sensing is formed by a photolithography method or a print method, and the on-chip lens
5
provided for increasing aperture rate is manufactured in a semiconductor manufacturing process, such as photolithography or a dry etching.
As a solid-state image sensing device used in such an image sensing system, there are a line sensor, an area sensor, and the like. These solid-state image sensing devices are used in various fields in accordance with their purposes, and the quality of the solid-state image sensing devices has improved year after year.
Next, spectral transmission characteristics of each area, corresponding to each pixel of the solid-state image sensing device
3
, of the color filter
4
which is provided in the solid-state image sensing device
3
will be explained.
FIGS. 46A
to
46
C and
FIGS. 47A
to
47
D are graphs showing spectral transmission characteristics of the color filter
4
formed on the solid-state image sensing device
3
. In these graphs, the horizontal axes show a wavelength (nm) and the vertical axes show spectral transmittance of the color filter
4
.
FIGS. 46A
to
46
C are the graphs showing examples of spectral transmission characteristics of a color filter of primary colors of red, green and blue. Specifically,
FIG. 46A
is a graph showing the spectral transmission characteristics of a red part of the color filter,
FIG. 46B
is a graph showing the spectral transmission characteristics of a green part of the color filter, and
FIG. 46C
is a graph showing the spectral transmission characteristics of a blue part of the color filter.
Referring to the red part of the color filter
4
whose spectral transmission characteristics are shown in
FIG. 46A
as an example, the spectral transmission characteristics of the color filter
4
will be explained. As shown in
FIG. 46A
, the red part of the color filter
4
has a high spectral transmittance for light in a long wavelength range areas of the visible light, whereas has a low spectral transmittance for light in other wavelength ranges, thus mainly transmits the light in the long wavelength range. Similarly, each of the green and blue parts of the color filter
4
show high and low spectral transmittances with respect to wavelength ranges, and light which passes through the green and blue color parts is in different wavelength ranges.
Further,
FIGS. 47A
to
47
D are graphs showing examples of spectral transmission characteristics of a color filter of complementary colors of cyan, magenta, yellow and green. Similarly to the spectral transmission characteristics of each color part of the color filter of primary colors as shown in
FIGS. 46A
to
46
C, different color parts of the color filter of complementary colors have different spectral transmission characteristics from each other.
Further,
FIGS. 48A and 48B
show examples of arrangement of color parts of a color filter of a common solid-state image sensing device used in a video camera and the like. As shown in
FIGS. 48A and 48B
, the color parts are arranged in a fixed pattern on the solid-state image sensing device.
Further, characters R, G and B in FIG.
4
BA respectively show the red, green and blue parts of the color filter of primary colors each having spectral transmission characteristics shown in
FIGS. 46A
to
46
C, and characters Cy, Mg, Ye and G in
FIG. 48B
respectively show the cyan, magenta, yellow and green parts of the color filter of complementary colors each having spectral transmission characteristics shown in
FIGS. 47A
to
47
D. Each square in
FIGS. 48A and 48B
corresponds to a pixel of a solid-state image sensing device.
When the aforesaid color filter is used in a solid-state image sensing device, since color parts are placed in a fixed pattern on pixels of the solid state image sensing device, each color of the light from the object is sampled at interval between color par
Kobayashi Shuichi
Wada Ken
Canon Kabushiki Kaisha
Garber Wendy R.
Morgan & Finnegan , LLP
Wilson Jacqueline
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