CA2460403A1 - Color filter patterns for image sensors - Google Patents
Color filter patterns for image sensors Download PDFInfo
- Publication number
- CA2460403A1 CA2460403A1 CA002460403A CA2460403A CA2460403A1 CA 2460403 A1 CA2460403 A1 CA 2460403A1 CA 002460403 A CA002460403 A CA 002460403A CA 2460403 A CA2460403 A CA 2460403A CA 2460403 A1 CA2460403 A1 CA 2460403A1
- Authority
- CA
- Canada
- Prior art keywords
- color
- filters
- image sensor
- colors
- color image
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000003086 colorant Substances 0.000 claims abstract description 82
- 230000000295 complement effect Effects 0.000 claims abstract description 8
- 238000001228 spectrum Methods 0.000 claims description 18
- 230000003287 optical effect Effects 0.000 claims description 4
- 239000011248 coating agent Substances 0.000 abstract description 8
- 238000000576 coating method Methods 0.000 abstract description 8
- 238000003384 imaging method Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 description 25
- 230000035945 sensitivity Effects 0.000 description 16
- 238000010586 diagram Methods 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 230000008859 change Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 230000004075 alteration Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 241000283153 Cetacea Species 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 230000035571 calor Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000009500 colour coating Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 230000003362 replicative effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/10—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from different wavelengths
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/1462—Coatings
- H01L27/14621—Colour filter arrangements
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Electromagnetism (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Color Television Image Signal Generators (AREA)
Abstract
Color filter patterns are invented for coating an array of imaging sensing elements so to obtain color images. Each of the color filter patterns consists of a luminance color Y
and two other complementary or non-overlapping colors tessellated in a Bayer pattern, hexagonal pattern, YUV422 pattern, or other ordered tessellation. In two preferred embodiments of the invention, the color filter pattern differs from a conventional Bayer Pattern or a conventional. hexagonal RGB pattern only in. that the G color is replaced by a luminance color Y but with varied pixel sizes. The color filter for luminance Y can be realized by a transparent coating or no coating at all. In addition, the effective sensing areas of different colors are so chosen that desired signal-to-noise ratios are obtained by adjusting flue color sensing areas and/or the sizes/curvatures of the micro lenses for the color pixels.
and two other complementary or non-overlapping colors tessellated in a Bayer pattern, hexagonal pattern, YUV422 pattern, or other ordered tessellation. In two preferred embodiments of the invention, the color filter pattern differs from a conventional Bayer Pattern or a conventional. hexagonal RGB pattern only in. that the G color is replaced by a luminance color Y but with varied pixel sizes. The color filter for luminance Y can be realized by a transparent coating or no coating at all. In addition, the effective sensing areas of different colors are so chosen that desired signal-to-noise ratios are obtained by adjusting flue color sensing areas and/or the sizes/curvatures of the micro lenses for the color pixels.
Description
COLOR FILTER PATTERNS FOR IMAGE SENSORS
BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates to color image sensors that converts optical illumination into electrical signal arrays. More particularly, this invention is related to a new color filter pattern for an image sensor to improve color image sensing sensitivity and total image quality when perceived from human eyes by adjusting signal to noise ratio of different colors.
BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates to color image sensors that converts optical illumination into electrical signal arrays. More particularly, this invention is related to a new color filter pattern for an image sensor to improve color image sensing sensitivity and total image quality when perceived from human eyes by adjusting signal to noise ratio of different colors.
2. Description of the Related Art Conventional technologies of designing and manufacturing color image sensors are still confronted with several technical difficulties and limitations. More specifically, color image sensors implemented with current technologies are still hindered by low level of sensing sensitivities, limited spatial resolutions and problems associated with color aliasing. Generally, an image sensor is applied for sensW g either black and white or color images. The invention of this Application is related to color image sensors. There are several different technologies implemented for the color image sensors to generate color images from a single array of sensing elements. The most commonly used method in a color image sensor is to coat on the surface of a sensing array with a special pattern of different color filters. Conventional color image sensors apply two kinds of color filter patterns. Fig. 1 shows the first color filter pattern, i.e., the CYeMgG
Pattern (or complementary color filter pattern), comprising C (Cyan), Ye (Yellow), Mg (Magenta), G
(Green) pattern. Figs. 2 and 3 show another kind of color filter patterns that utilize primary color filters, comprising R (Red), G (Green), and B (Blue), arranged in either a Bayer Pattern shown in Figure 2 or a Hexagonal RGB Pattern as that shown in Fig. 3.
In a color image sensor implemented with the CYeMgG Pattern, the sensing element array is formed by a plurality of macro pixels, with each macro pixel consisting of 4 {elementary) pixels. Each pixel is coated with a single color, either C, or Ye, or Mg, or G. However, since the display industry commonly uses the primary color pattern, i.e., RGB (red, green, blue) colors, instead of a CYeMgG pattern, therefore, conversion of a CYeMgG color pattern into a RGB color pattern is carried out by performing the color matrix operations. Furthermore, since each pixel contains only one color (either C, or Ye, or Mg, or G), in order to obtain other (R, G, and B) colors for the same pixel, interpolation methods are used to generate the missing colors from neighboring pixels. For an image sensor implemented with a Bayer Pattern (US Patent#3,971,065), the sensing element array is also formed by a plurality of macro pixels, with each macro pixel consisting of four pixels coated with either R, or G, or B color filter. A Bayer Pattern further requires that among each macro pixel, two pixels in either diagonal direction must be coated with G or LumW ance and the other two pixels :must be coated ~Nith B and R or two other colors sensitive to DIFFERENT spE3ctral regions. Again since each pixel contains only one color (either R, or G, or B), in order to obtain oilier (two) colors for the same pixel, interpolation methods are used to generate the missing colors from neighboring pixels.
Bayer pattern has four different geometric structures, with R, G, B located in different locations in the four pixels. Referring to Fig. 3 again for the Hexagonal RGB
Pattern, a macro pixel contains only three sensing pixels of R, G, and B wherein each element is tessellated in hexagonal fashion. The R, G, B colors are equally and evenly placed in the sensing array. Interchanging the positions of two colors still form a Hexagonal RGB
Pattern.
As discussed above, the color filter technologies that implement either the CYeMgG Pattern, Bayer Pattern, or Hexagonal RGB Pattern have at least three common technical difficulties. A first difficulty is the reduction of sensing sensitivities caused by the use of multiple layers of filters when compared to black and white sensors. 'The second difficulty is the reduction of effective spatial resolution due to the need of color interpolation. The requirement of color interpolation also introduces the third difficulty of color abasing, which can be solved, typically, by low pass filtering, that however leads to reduction in image sharpness.
In order to improve the overall sensing sensitivity, U~ Patent 6,137,100 discloses ~
method by balancing the responses from sensing the three primary colors R, G, and B by taking into consideration of the fact that the color sensitivities of the photodiodes are different, specifically, the photodiodes are most sensitive to green then to red and lastly least sensitive to blue. TTie Patented method thus provides largest sensing area to blue pixels, and the second largest sensing area to red pixels, and the least sensing area to green pixels. However, the improvements in color sensing sensitivity achieved by this technique are still quite limited and also the methods are only applicable to the image sensor implemented with the color filters of RGB color patterns.
In order to avoid a requirement of color interpolations, a new calor image sensor produced by Foveon is implemented with a three-Layer image sensor as that shown in Fig.4. This three-layer color sensor, designated by a model number as "X3 image sensor", contains three layers of sensing array, with each layer sensing R, G, or B
light spectxum respectively. The X3 image sensor is able to resolve the difficulties caused by color interpolation, but generates new problems due to the difference of the sensing sensitivities between different layers. The sensing sensitivity of a Lower layer is smaller than that of the top layer. Therefore, the overall effective sensing sensitivity is further reduced. Additionally, the production yields are degraded as three layers of sensor are manufactured and assembled by using more complicate and time consuming manufacturing processes. Furthermore, there are three times of data to be processed and that places additional demand on data transfer and data processing rates and causes a significant increase of the production costs of the entire system implemented with this X3 image sensor.
Therefore, a need still exists to provide new and improved tecluliques and methods for designing and manufacturing a color image sensor to resolve these technical difficulties.
Pattern (or complementary color filter pattern), comprising C (Cyan), Ye (Yellow), Mg (Magenta), G
(Green) pattern. Figs. 2 and 3 show another kind of color filter patterns that utilize primary color filters, comprising R (Red), G (Green), and B (Blue), arranged in either a Bayer Pattern shown in Figure 2 or a Hexagonal RGB Pattern as that shown in Fig. 3.
In a color image sensor implemented with the CYeMgG Pattern, the sensing element array is formed by a plurality of macro pixels, with each macro pixel consisting of 4 {elementary) pixels. Each pixel is coated with a single color, either C, or Ye, or Mg, or G. However, since the display industry commonly uses the primary color pattern, i.e., RGB (red, green, blue) colors, instead of a CYeMgG pattern, therefore, conversion of a CYeMgG color pattern into a RGB color pattern is carried out by performing the color matrix operations. Furthermore, since each pixel contains only one color (either C, or Ye, or Mg, or G), in order to obtain other (R, G, and B) colors for the same pixel, interpolation methods are used to generate the missing colors from neighboring pixels. For an image sensor implemented with a Bayer Pattern (US Patent#3,971,065), the sensing element array is also formed by a plurality of macro pixels, with each macro pixel consisting of four pixels coated with either R, or G, or B color filter. A Bayer Pattern further requires that among each macro pixel, two pixels in either diagonal direction must be coated with G or LumW ance and the other two pixels :must be coated ~Nith B and R or two other colors sensitive to DIFFERENT spE3ctral regions. Again since each pixel contains only one color (either R, or G, or B), in order to obtain oilier (two) colors for the same pixel, interpolation methods are used to generate the missing colors from neighboring pixels.
Bayer pattern has four different geometric structures, with R, G, B located in different locations in the four pixels. Referring to Fig. 3 again for the Hexagonal RGB
Pattern, a macro pixel contains only three sensing pixels of R, G, and B wherein each element is tessellated in hexagonal fashion. The R, G, B colors are equally and evenly placed in the sensing array. Interchanging the positions of two colors still form a Hexagonal RGB
Pattern.
As discussed above, the color filter technologies that implement either the CYeMgG Pattern, Bayer Pattern, or Hexagonal RGB Pattern have at least three common technical difficulties. A first difficulty is the reduction of sensing sensitivities caused by the use of multiple layers of filters when compared to black and white sensors. 'The second difficulty is the reduction of effective spatial resolution due to the need of color interpolation. The requirement of color interpolation also introduces the third difficulty of color abasing, which can be solved, typically, by low pass filtering, that however leads to reduction in image sharpness.
In order to improve the overall sensing sensitivity, U~ Patent 6,137,100 discloses ~
method by balancing the responses from sensing the three primary colors R, G, and B by taking into consideration of the fact that the color sensitivities of the photodiodes are different, specifically, the photodiodes are most sensitive to green then to red and lastly least sensitive to blue. TTie Patented method thus provides largest sensing area to blue pixels, and the second largest sensing area to red pixels, and the least sensing area to green pixels. However, the improvements in color sensing sensitivity achieved by this technique are still quite limited and also the methods are only applicable to the image sensor implemented with the color filters of RGB color patterns.
In order to avoid a requirement of color interpolations, a new calor image sensor produced by Foveon is implemented with a three-Layer image sensor as that shown in Fig.4. This three-layer color sensor, designated by a model number as "X3 image sensor", contains three layers of sensing array, with each layer sensing R, G, or B
light spectxum respectively. The X3 image sensor is able to resolve the difficulties caused by color interpolation, but generates new problems due to the difference of the sensing sensitivities between different layers. The sensing sensitivity of a Lower layer is smaller than that of the top layer. Therefore, the overall effective sensing sensitivity is further reduced. Additionally, the production yields are degraded as three layers of sensor are manufactured and assembled by using more complicate and time consuming manufacturing processes. Furthermore, there are three times of data to be processed and that places additional demand on data transfer and data processing rates and causes a significant increase of the production costs of the entire system implemented with this X3 image sensor.
Therefore, a need still exists to provide new and improved tecluliques and methods for designing and manufacturing a color image sensor to resolve these technical difficulties.
SUMMARY OF THE PRESENT INVENTION
An object of this W vention is to provide a new color filter pattern for color image sensors. The image sensor implemented with this new color filter pattern provides an improved color image sensing sensitivity and image sharpness compared with the traditional CYeMgG pattern, Bayer pattern, or hexagonal pattern. Therefore, the limitations and difficulties as those encountered in the prior art are resolved.
In a first aspect of the invention, the color filter patterns contain three colors, and one of these three colors is the luminance of the whole interested spectrum (e.g., the white color in the visible light spectrum) commonly designated as Y. This color is designated as the leading color. The color filter for luminance is realized by either a transparent coating or by applying no coating at all to the filter.
In a second aspect of the invention, besides the luminance filter, the image sensor includes tcnTo other color filters that can be of any two complementary colors or two primary colors, designated as secondary colors and labeled as S and Q for ease of description in this Application. For example, S can be Yellowr, and Q can be Cyan, or S
can be Red and Q be Blue. The color filter for a particular color, e.g., Yellow, is realized by a coating material or pigments that pass tight spectrum corresponding to that particular color, e.g., Yellow.
In a third aspect of the invention, irrespective of which form of tessellation is used, the leading color Y must be coated on at least the same number of pixels than each of the secondary colors S and Q while S is coated on about the same number of pixels as Q. The new color filter pattern may be applied in many different forms of tessellation including, but not restricted to, the conventional Bayer Pattern tessellation as that shown in Fig. 5, hexagonal tessellation as that shown in Fig. 7, or the YUV422 tessellation as that shown in Fig. 9.
In a fourth aspect of the invention, the sensing areas of the pixels or surface areas of the micro lenses on the pixels are designed such that the three kinds of sensing elements for Y, S, and Q colors have the desired signal to noise ratios (SNR) for the lighting condition of particular applications implemented with the image sensor of this invention.
Briefly in a preferred embodiment this invention discloses a method: for generating a color filter pattern for a macro pixel of foul elementary pixels. The color filter pattern includes a luminance color Y and two other colors S and Q organized in ordered tessellation. The tessellation includes Bayer tessellation and YUV422 tessellation. The YUV422 tessellation is widely used as YUV422 format in TV industry where YUV
data are organized ii1 YUYV interleave format. The method includes a step of coating the color filter pattern on top of a macro pixel with color Y on two elementary sensing pixel elements, and S and Q each on top of one elementary sensing pixel element. The method further includes a step of replicating the macro pixel with the said color filter pattern in tile tessellation horizontally and vertically so to obtain an image sensor array.
These and other objects and advantages of the present invention will no doubt come obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments, which are illustrated in the various drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a diagram of a CYeMgG color filter pattern;
Figures 2 is a diagram of RGB Bayer color filter pattern and the variants;
Figure 3 is a diagram of the Hexagonal RGB color filter pattern;
Figure 4 is a diagram for showing the three-layer color filter technique implemented by Foveon, Inc. in a X3 image sensor;
Figure 5 is a diagram fox illustrating the YSQ color filter pattern according to a Bayer Tessellation and its variants according to the present invention;
Figure 6 shows a preferred embodiment implemented with YYeC color filters of this invention arranged according to a Bayer tessellations;
Figure ~ is a diagram for illustrating an alternated preferred embodiment of this invention implemented with YSQ color filters arranged according to a 'Hexagonal Tessellation;
Fig. 8 is a diagram for illustrating an alternated preferred embodiment of this invention implemented with YYeC color filters arranged according to a Hexagonal Tessellation;
Figure 9 is a diagram of the newly invented YSQ color filter in different forms of YUV422 Tessellation;
Figure 10 is a diagram for illustrating an alternated preferred embodiment of this invention implemented with YBR color filters arranged according to different forms of YUV422 Tessellation;
Figures 11.A and 11 B show cross sectional views of image sensors implemented with micro-lenses wherein the SNRs of different color pixels are adjusted to W
a desired values by applying a micro-lens based SNR adjustment method through size and curvature variations of micro-lenses to change effective sensing areas;
Figure 12 is an area diagram fc7r illustrating an area-based SNR adjustment method to adjust the SNRs of different color pixels to the desired values.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figs. 5A to 5D for four different color filter patterns respectively wherein each pattern includes a plurality of luminance filters designated as Y
and two other color filters designated as S and Q. The Y color filters for sensing luminance, i.e., white light, are leading color filters and the S and Q filters are secondary color filters.
The secondary color filters S and Q can be implemented with two complementary color filters or two primary color filters. Compared to the number of pixels coated with S and Q color filters, luminance color filters as shown are coated on number of pixels equal to or more than that coated on either the S or Q color filters. The number of pixels coated with S color filters is about the same as the number of pixels that coated with Q color filters.
Referring to Fig. 6A to 6D, two secondary colors S and Q are chosen to be Yellow (Ye) alld CG'an (C)respectively and Y, S, and Q are organized in a Bayer pattern. With this preferred embodiment, the color filter pattern differs from the conventional Bayer pattern only in that Green color filter is replaced by White color filter, Red by Yello~~, and Blue by Clan. Compared to the conventional Bayer pattern, the color sensor as shown in Fig. 6 requires significant changes to generate color images. The changes are required because the sensed three colors Y, S and Q, e.g., Y, Ye, and C, do not form a color space and they have never been used together in image sensors. For this reason, the color filter patterns as shown in Figs. 5 and b require the internal color processing circuits to change correspondingly. Additionally, different color interpolation methods and matrix operations are needed to recover R, G, B colors from Bayer patterned now sensed as Y, S, Q, e.g., Y, Ye, C colors.
This seemingly simple change to the color filter patterns as shown in Figs. 5 and 6, provides great advantages. First of all, the white color Y has much higher sensitivity than green color, and yellow and cyan have much higher sensitivity than red and blue respectively. The color image sensor configured according to tile color filter pattern as shown can achieve much improved sensing sensitivity. Especially, SiIlCe human eyes are more sensitive to luminance than chrominance and since there are more luminance components than other color components, for a human viewer the image sharpness is increased. Second, both yellow and cyan are complementary colors and therefore do not represent chrominance colors (B and R) directly. As a consequency, the chrominance components need to be indirectly derived from color interpolation.
Figs. 7 and 8 show a second set of preferred embodiment where the YSQ patterns are implemented in Fig. 7 according to a hexagonal tessellation. In Fig. 8, the YSQ color filter pattern is again arranged according to a hexagonal tessellation with S
chosen as Yellow and Q chosen as Cyan. In this tessellation, Y, Ye, and C have about the same number of pixels. Meanwhile, in order to achieve better signal to noise ratios as will be discussed below, the sensing areas may be configured differently by pr oviding either different filter areas or using micro lenses of different curvatures.
Figs. 9 and 10 show a third set of preferred embodiment where the YSQ patterns are implemented in Fig. 9 according to a YUV422 tessellation. In Fig. 10, the YSQ color filter pattern is again arranged according to a YUV422 tessellation with S
chosen as R
and Q chosen as B. In this embodiment, the Y, B, and R colors are used for coating the pixels and these pixels are arranged in horizontally interleaved tessellation including either Y ( B ~ Y / R, Y ~ R ~ Y ( B, B ( Y ~ R ~ Y, or R ~ Y ~ B ~ Y. Compared with the horizontal resolution, the vertical resolution is twice as higher for Y, and four times higher for B and R. In order to have a more balanced resolution, different methods are implemented. As a first exemplary implementation, the combined width of a macro pixel Y ~ B ( Y ~ R, is arranged as twice as the height of a Y pixel. In a second exemplary implementation, instead of four pixels, two (R, G, B) pixels are produced through interpolation from each macro pixel Y ~ B ~ Y ~ R. Because of the similarity with the YUV422 format widely used iti the TV industry, this preferred embodiment is particularly useful for video sensors. Even this embodiment has similar tessellations as that shown in US Patent 6,346,969, the invention as disclosed in this Application has superior image quality because of the improved effective sensing sensitivity by utilizing an improved Y-S-Q color filters instead of the conventional RGB color filters when compared with US Patent 6,346,969.
In all three different tessellations, as those shown in Figs. 5 to 10, there are more or about same Y pixels when compared to S and Q pixels. Meanwhile, the S and Q
pixels have about the same numbers of pixels.
The color image sensor has broad applications. For example, a digital camera can achieve immediate image quality improvement by utilizing a color image sensor as disclosed in this invention. Typically, a digital camera can easily achieve acceptable signal to noise ratio for an outdoor situation. However, in a low light condition such as - 9 - BMCll 02 the requirements for taking an indoor picture, conventional color image sensors often experience difficulties to provide sufficient image sensing sensitivity. In a low light environment, the SNR for a sensing element highly depends on the color coating and semiconductor processing technology of the sensing element {e.g., a photo diode).
Normally, luminance Y has the highest SNR among all colors. Suppose that S has a higher SNR than Q. Let SY, Ss, SQ, be the intrinsic SNR of the sensing element for color Y, S, and Q respectively. 'The intrinsic SNR of a color is defined as the SNR of the color at unit sensing area. Typically the signal to noise ratio can be calculated as:
Ss = SY / a, SQ = SY / b, (b >= a > 1.0).
If the desired SNRs for Y, S, and Q are DY, Ds, D~ respectively with Ds = DY / c, DQ = DY / d, Then sensing areas or the surface areas of the micro lenses for the Y, S, and Q pixels are chosen such that a S pixel collects a/c times more photons than a Y pixel, and a Q pixel collects b/ d times more photons than a Y pixel. Furthermore, it is noted that:
a/c ° ( SY / Ss) / (DY / Ds) _ (SY' Ds) / (Ss 'DY) b/ d = C SY / sQ) / (DY / DQ) ° (SY ' DQ> / (sQ ' DY>
The difference between sensing areas or surface areas of the micro lenses between a color pair S and Y, or Q and Y, is determined by both the desired and intrinsic SNRs of S and Y, or those of Q and Y. As shown in Fig. 11, the desired SNRs are achieved by adjusting surface areas or curvatures of the micro lenses for different colors. These drawings are exemplary and are not intended to limit the scope of this invention. The method of using the micro lenses for sensing areas adjustment can be either used independently or together with the sensing area adjustment method described below.
Fig. 12 shows a method that achieves desired SNRs by adjusting sensing areas of different color pixels. Compared to the disclosure made in US Patent 6,137,100, the SNR
balancing techniques are different. The balancing techniques as disclosed by US Patent 6,137,100 is only applied to the conventional R-G-B color space and the Bayer tessellation, while the balance of this invention is applied to the Y-S-Q color space for all different kinds of tessellations. Furthermore, the SNR balancing method of this invention is not to equalize the color light photons received for R, G, and B pixels respectively, but to achieve the desired SNRs for Y, S, and Q respectively. The technique of this invention can produce better image quality for human eyes. The better image qualities are achieved because the human eyes are more sensitive to luminance than to cllrominance.
For this reason, the desired SNR for Y is higher than the desired SNRs for S
and Q.
Instead of adjusting even intensity of the R-G-B colors, a more sensible adjustment is to adjust the SNRs for better viewing as that most suitable for human eyes when looking from a human perspective. Other than the changes of planar sensing areas as shown in Fig. 12, additional sensing area adjustment can be achieved by using micro lenses on different color filters as that shown in Fig. 11 with micro lenses of different sizes and curvatures. The SNRs can therefore be flexibly adjusted to achieve best image quality by combining planar sensing area var rations together with micro lens adjustments.
In summary, this invention discloses an improved color image sensor implemented with a color filter pattern that has a leading color, the luminance (or white color as in the visible light spectrum) Y of the whale interested spectrum, and two other secondary colors S and Q each corresponding one segment of the interested spectrum. The secondary colors S and Q can be chosen from any two of the primary colors R, G, and B, or from any complementary color pairs out of C, Ye, Mg, and G, or from two other specifically desired colors (e.g., an infrared color and an ultraviolet color) for special applications. The leading color is applied to about the same or more number of pixels than each of the secondary colors. The color filter pattern can have any form of tessellation, including, but not restricted to, Bayer pattern tessellation, hexagonal tessellation, or YUV422 tessellation. The sensing areas and/or surface areas or curvature of the micro lenses of the color pixels are so chosen to achieve desired SNRs for the color pixels. This inventions thus uses a different color filter pattern to improve the sensitivity and increase image sharpness without the side effects of the X3 method. In addition, the method can be used to produce YUV sensors in very simple ways.
Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after reading the above disclosure.
Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.
An object of this W vention is to provide a new color filter pattern for color image sensors. The image sensor implemented with this new color filter pattern provides an improved color image sensing sensitivity and image sharpness compared with the traditional CYeMgG pattern, Bayer pattern, or hexagonal pattern. Therefore, the limitations and difficulties as those encountered in the prior art are resolved.
In a first aspect of the invention, the color filter patterns contain three colors, and one of these three colors is the luminance of the whole interested spectrum (e.g., the white color in the visible light spectrum) commonly designated as Y. This color is designated as the leading color. The color filter for luminance is realized by either a transparent coating or by applying no coating at all to the filter.
In a second aspect of the invention, besides the luminance filter, the image sensor includes tcnTo other color filters that can be of any two complementary colors or two primary colors, designated as secondary colors and labeled as S and Q for ease of description in this Application. For example, S can be Yellowr, and Q can be Cyan, or S
can be Red and Q be Blue. The color filter for a particular color, e.g., Yellow, is realized by a coating material or pigments that pass tight spectrum corresponding to that particular color, e.g., Yellow.
In a third aspect of the invention, irrespective of which form of tessellation is used, the leading color Y must be coated on at least the same number of pixels than each of the secondary colors S and Q while S is coated on about the same number of pixels as Q. The new color filter pattern may be applied in many different forms of tessellation including, but not restricted to, the conventional Bayer Pattern tessellation as that shown in Fig. 5, hexagonal tessellation as that shown in Fig. 7, or the YUV422 tessellation as that shown in Fig. 9.
In a fourth aspect of the invention, the sensing areas of the pixels or surface areas of the micro lenses on the pixels are designed such that the three kinds of sensing elements for Y, S, and Q colors have the desired signal to noise ratios (SNR) for the lighting condition of particular applications implemented with the image sensor of this invention.
Briefly in a preferred embodiment this invention discloses a method: for generating a color filter pattern for a macro pixel of foul elementary pixels. The color filter pattern includes a luminance color Y and two other colors S and Q organized in ordered tessellation. The tessellation includes Bayer tessellation and YUV422 tessellation. The YUV422 tessellation is widely used as YUV422 format in TV industry where YUV
data are organized ii1 YUYV interleave format. The method includes a step of coating the color filter pattern on top of a macro pixel with color Y on two elementary sensing pixel elements, and S and Q each on top of one elementary sensing pixel element. The method further includes a step of replicating the macro pixel with the said color filter pattern in tile tessellation horizontally and vertically so to obtain an image sensor array.
These and other objects and advantages of the present invention will no doubt come obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments, which are illustrated in the various drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a diagram of a CYeMgG color filter pattern;
Figures 2 is a diagram of RGB Bayer color filter pattern and the variants;
Figure 3 is a diagram of the Hexagonal RGB color filter pattern;
Figure 4 is a diagram for showing the three-layer color filter technique implemented by Foveon, Inc. in a X3 image sensor;
Figure 5 is a diagram fox illustrating the YSQ color filter pattern according to a Bayer Tessellation and its variants according to the present invention;
Figure 6 shows a preferred embodiment implemented with YYeC color filters of this invention arranged according to a Bayer tessellations;
Figure ~ is a diagram for illustrating an alternated preferred embodiment of this invention implemented with YSQ color filters arranged according to a 'Hexagonal Tessellation;
Fig. 8 is a diagram for illustrating an alternated preferred embodiment of this invention implemented with YYeC color filters arranged according to a Hexagonal Tessellation;
Figure 9 is a diagram of the newly invented YSQ color filter in different forms of YUV422 Tessellation;
Figure 10 is a diagram for illustrating an alternated preferred embodiment of this invention implemented with YBR color filters arranged according to different forms of YUV422 Tessellation;
Figures 11.A and 11 B show cross sectional views of image sensors implemented with micro-lenses wherein the SNRs of different color pixels are adjusted to W
a desired values by applying a micro-lens based SNR adjustment method through size and curvature variations of micro-lenses to change effective sensing areas;
Figure 12 is an area diagram fc7r illustrating an area-based SNR adjustment method to adjust the SNRs of different color pixels to the desired values.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figs. 5A to 5D for four different color filter patterns respectively wherein each pattern includes a plurality of luminance filters designated as Y
and two other color filters designated as S and Q. The Y color filters for sensing luminance, i.e., white light, are leading color filters and the S and Q filters are secondary color filters.
The secondary color filters S and Q can be implemented with two complementary color filters or two primary color filters. Compared to the number of pixels coated with S and Q color filters, luminance color filters as shown are coated on number of pixels equal to or more than that coated on either the S or Q color filters. The number of pixels coated with S color filters is about the same as the number of pixels that coated with Q color filters.
Referring to Fig. 6A to 6D, two secondary colors S and Q are chosen to be Yellow (Ye) alld CG'an (C)respectively and Y, S, and Q are organized in a Bayer pattern. With this preferred embodiment, the color filter pattern differs from the conventional Bayer pattern only in that Green color filter is replaced by White color filter, Red by Yello~~, and Blue by Clan. Compared to the conventional Bayer pattern, the color sensor as shown in Fig. 6 requires significant changes to generate color images. The changes are required because the sensed three colors Y, S and Q, e.g., Y, Ye, and C, do not form a color space and they have never been used together in image sensors. For this reason, the color filter patterns as shown in Figs. 5 and b require the internal color processing circuits to change correspondingly. Additionally, different color interpolation methods and matrix operations are needed to recover R, G, B colors from Bayer patterned now sensed as Y, S, Q, e.g., Y, Ye, C colors.
This seemingly simple change to the color filter patterns as shown in Figs. 5 and 6, provides great advantages. First of all, the white color Y has much higher sensitivity than green color, and yellow and cyan have much higher sensitivity than red and blue respectively. The color image sensor configured according to tile color filter pattern as shown can achieve much improved sensing sensitivity. Especially, SiIlCe human eyes are more sensitive to luminance than chrominance and since there are more luminance components than other color components, for a human viewer the image sharpness is increased. Second, both yellow and cyan are complementary colors and therefore do not represent chrominance colors (B and R) directly. As a consequency, the chrominance components need to be indirectly derived from color interpolation.
Figs. 7 and 8 show a second set of preferred embodiment where the YSQ patterns are implemented in Fig. 7 according to a hexagonal tessellation. In Fig. 8, the YSQ color filter pattern is again arranged according to a hexagonal tessellation with S
chosen as Yellow and Q chosen as Cyan. In this tessellation, Y, Ye, and C have about the same number of pixels. Meanwhile, in order to achieve better signal to noise ratios as will be discussed below, the sensing areas may be configured differently by pr oviding either different filter areas or using micro lenses of different curvatures.
Figs. 9 and 10 show a third set of preferred embodiment where the YSQ patterns are implemented in Fig. 9 according to a YUV422 tessellation. In Fig. 10, the YSQ color filter pattern is again arranged according to a YUV422 tessellation with S
chosen as R
and Q chosen as B. In this embodiment, the Y, B, and R colors are used for coating the pixels and these pixels are arranged in horizontally interleaved tessellation including either Y ( B ~ Y / R, Y ~ R ~ Y ( B, B ( Y ~ R ~ Y, or R ~ Y ~ B ~ Y. Compared with the horizontal resolution, the vertical resolution is twice as higher for Y, and four times higher for B and R. In order to have a more balanced resolution, different methods are implemented. As a first exemplary implementation, the combined width of a macro pixel Y ~ B ( Y ~ R, is arranged as twice as the height of a Y pixel. In a second exemplary implementation, instead of four pixels, two (R, G, B) pixels are produced through interpolation from each macro pixel Y ~ B ~ Y ~ R. Because of the similarity with the YUV422 format widely used iti the TV industry, this preferred embodiment is particularly useful for video sensors. Even this embodiment has similar tessellations as that shown in US Patent 6,346,969, the invention as disclosed in this Application has superior image quality because of the improved effective sensing sensitivity by utilizing an improved Y-S-Q color filters instead of the conventional RGB color filters when compared with US Patent 6,346,969.
In all three different tessellations, as those shown in Figs. 5 to 10, there are more or about same Y pixels when compared to S and Q pixels. Meanwhile, the S and Q
pixels have about the same numbers of pixels.
The color image sensor has broad applications. For example, a digital camera can achieve immediate image quality improvement by utilizing a color image sensor as disclosed in this invention. Typically, a digital camera can easily achieve acceptable signal to noise ratio for an outdoor situation. However, in a low light condition such as - 9 - BMCll 02 the requirements for taking an indoor picture, conventional color image sensors often experience difficulties to provide sufficient image sensing sensitivity. In a low light environment, the SNR for a sensing element highly depends on the color coating and semiconductor processing technology of the sensing element {e.g., a photo diode).
Normally, luminance Y has the highest SNR among all colors. Suppose that S has a higher SNR than Q. Let SY, Ss, SQ, be the intrinsic SNR of the sensing element for color Y, S, and Q respectively. 'The intrinsic SNR of a color is defined as the SNR of the color at unit sensing area. Typically the signal to noise ratio can be calculated as:
Ss = SY / a, SQ = SY / b, (b >= a > 1.0).
If the desired SNRs for Y, S, and Q are DY, Ds, D~ respectively with Ds = DY / c, DQ = DY / d, Then sensing areas or the surface areas of the micro lenses for the Y, S, and Q pixels are chosen such that a S pixel collects a/c times more photons than a Y pixel, and a Q pixel collects b/ d times more photons than a Y pixel. Furthermore, it is noted that:
a/c ° ( SY / Ss) / (DY / Ds) _ (SY' Ds) / (Ss 'DY) b/ d = C SY / sQ) / (DY / DQ) ° (SY ' DQ> / (sQ ' DY>
The difference between sensing areas or surface areas of the micro lenses between a color pair S and Y, or Q and Y, is determined by both the desired and intrinsic SNRs of S and Y, or those of Q and Y. As shown in Fig. 11, the desired SNRs are achieved by adjusting surface areas or curvatures of the micro lenses for different colors. These drawings are exemplary and are not intended to limit the scope of this invention. The method of using the micro lenses for sensing areas adjustment can be either used independently or together with the sensing area adjustment method described below.
Fig. 12 shows a method that achieves desired SNRs by adjusting sensing areas of different color pixels. Compared to the disclosure made in US Patent 6,137,100, the SNR
balancing techniques are different. The balancing techniques as disclosed by US Patent 6,137,100 is only applied to the conventional R-G-B color space and the Bayer tessellation, while the balance of this invention is applied to the Y-S-Q color space for all different kinds of tessellations. Furthermore, the SNR balancing method of this invention is not to equalize the color light photons received for R, G, and B pixels respectively, but to achieve the desired SNRs for Y, S, and Q respectively. The technique of this invention can produce better image quality for human eyes. The better image qualities are achieved because the human eyes are more sensitive to luminance than to cllrominance.
For this reason, the desired SNR for Y is higher than the desired SNRs for S
and Q.
Instead of adjusting even intensity of the R-G-B colors, a more sensible adjustment is to adjust the SNRs for better viewing as that most suitable for human eyes when looking from a human perspective. Other than the changes of planar sensing areas as shown in Fig. 12, additional sensing area adjustment can be achieved by using micro lenses on different color filters as that shown in Fig. 11 with micro lenses of different sizes and curvatures. The SNRs can therefore be flexibly adjusted to achieve best image quality by combining planar sensing area var rations together with micro lens adjustments.
In summary, this invention discloses an improved color image sensor implemented with a color filter pattern that has a leading color, the luminance (or white color as in the visible light spectrum) Y of the whale interested spectrum, and two other secondary colors S and Q each corresponding one segment of the interested spectrum. The secondary colors S and Q can be chosen from any two of the primary colors R, G, and B, or from any complementary color pairs out of C, Ye, Mg, and G, or from two other specifically desired colors (e.g., an infrared color and an ultraviolet color) for special applications. The leading color is applied to about the same or more number of pixels than each of the secondary colors. The color filter pattern can have any form of tessellation, including, but not restricted to, Bayer pattern tessellation, hexagonal tessellation, or YUV422 tessellation. The sensing areas and/or surface areas or curvature of the micro lenses of the color pixels are so chosen to achieve desired SNRs for the color pixels. This inventions thus uses a different color filter pattern to improve the sensitivity and increase image sharpness without the side effects of the X3 method. In addition, the method can be used to produce YUV sensors in very simple ways.
Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after reading the above disclosure.
Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.
Claims (39)
1. A color image sensor comprising:
at least a first color filter for sensing a luminance from an entire spectrum relevant to said color image sensor.
at least a first color filter for sensing a luminance from an entire spectrum relevant to said color image sensor.
2. The color image sensor of claim 1 further comprising:
a second filter of a second color and a third filter of a third color wherein said second and third colors correspond two overlapping segments of said entire spectrum.
a second filter of a second color and a third filter of a third color wherein said second and third colors correspond two overlapping segments of said entire spectrum.
3. The color image sensor of claim 1 further comprising:
a plurality of first color filters for sensing a luminance from an entire spectrum relevant to said color sensor;
a plurality of second filters of a second color and a plurality of third filter of a third color wherein said second and third colors correspond two overlapping segments of said entire spectrum.
a plurality of first color filters for sensing a luminance from an entire spectrum relevant to said color sensor;
a plurality of second filters of a second color and a plurality of third filter of a third color wherein said second and third colors correspond two overlapping segments of said entire spectrum.
4. The color image sensor of claim 3 wherein:
said color image sensor having more or an about same number of filters of said first color than said filters of said second color and said filters of said third color.
said color image sensor having more or an about same number of filters of said first color than said filters of said second color and said filters of said third color.
5. The color image sensor of claim 3 wherein:
said filters of said first color and said filters of said second and third colors are configured according to a Bayer tessellation.
said filters of said first color and said filters of said second and third colors are configured according to a Bayer tessellation.
6. The color image sensor of claim 3 wherein:
said filters of said first color and said filters of said second and third colors are configured according to a hexagonal tessellation.
said filters of said first color and said filters of said second and third colors are configured according to a hexagonal tessellation.
7. The color image sensor of claim 3 wherein:
said filters of said white color and said filters of said second and third colors are configured according to a YUV422 tessellation.
said filters of said white color and said filters of said second and third colors are configured according to a YUV422 tessellation.
8. A color image sensor of claim 1 wherein:
said first color filter is for sensing a luminance from an entire spectrum of a visible color for a human eve.
said first color filter is for sensing a luminance from an entire spectrum of a visible color for a human eve.
9. The color image sensor of claim 8 further comprising:
a second filter of a second color, and a third filter of a third color wherein said second and third colors are two complementary visible colors for a human eye.
a second filter of a second color, and a third filter of a third color wherein said second and third colors are two complementary visible colors for a human eye.
10. The color image sensor of claim 8 further comprising:
a second filter of a yellow color, and a third filter of a cyan color.
a second filter of a yellow color, and a third filter of a cyan color.
11. The color image sensor of claim 8 further comprising:
a plurality of white color filters for sensing a luminance from an entire spectrum of a visible color for a human eye;
a plurality of second filters of a second color and a plurality of third filter of a third color wherein said second and third colors are two different complementary colors to the primary colors.
a plurality of white color filters for sensing a luminance from an entire spectrum of a visible color for a human eye;
a plurality of second filters of a second color and a plurality of third filter of a third color wherein said second and third colors are two different complementary colors to the primary colors.
12. The color image sensor of claim 11 wherein:
said color image sensor having more or an about same number of filters of said white color than said filters of said second color and said filters of said third color.
said color image sensor having more or an about same number of filters of said white color than said filters of said second color and said filters of said third color.
13. The color image sensor of claim 11 wherein:
said filters of said white color and said filters of said second and third colors are configured according to a Bayer tessellation.
said filters of said white color and said filters of said second and third colors are configured according to a Bayer tessellation.
14. The color image sensor of claim 11 wherein:
said filters of said white color and said filters of said second and third colors are configured according to a hexagonal tessellation.
said filters of said white color and said filters of said second and third colors are configured according to a hexagonal tessellation.
15. The color image sensor of claim 11 wherein:
said filters of said white color and said filters of said second and third colors are configured according to a YUV422 tessellation.
said filters of said white color and said filters of said second and third colors are configured according to a YUV422 tessellation.
16. The color image sensor of claim 3 wherein:
said color image sensor is configured with a set of desired signal-to-noise ratios of said first color and said second and third colors by adjusting a first area covered by said first filters of said first color and a second and third areas covered by said second and third filters of said second and third colors respectfully.
said color image sensor is configured with a set of desired signal-to-noise ratios of said first color and said second and third colors by adjusting a first area covered by said first filters of said first color and a second and third areas covered by said second and third filters of said second and third colors respectfully.
17. The color image sensor of claim 3 wherein:
said color image sensor is configured with a set of desired signal-to-noise ratios of said first color and said second and third colors by adjusting a first effective sensing area of the micro lens of said first filters of said first color and a second and third effective sensing areas of said second and third filters of said second and third colors respectfully wherein each of said second and third filters covered by a micro lens.
said color image sensor is configured with a set of desired signal-to-noise ratios of said first color and said second and third colors by adjusting a first effective sensing area of the micro lens of said first filters of said first color and a second and third effective sensing areas of said second and third filters of said second and third colors respectfully wherein each of said second and third filters covered by a micro lens.
18. The color image sensor of claim 11 wherein:
said color image sensor is configured with a set of desired signal-to-noise ratios of said luminance and said second and third colors by adjusting a first area covered by said first filters of said luminance and a second and third areas covered by said second and third filters of said second and third colors respectfully.
said color image sensor is configured with a set of desired signal-to-noise ratios of said luminance and said second and third colors by adjusting a first area covered by said first filters of said luminance and a second and third areas covered by said second and third filters of said second and third colors respectfully.
19. The color image sensor of claim 11 wherein:
said color image sensor is configured with a set of desired signal-to-noise ratios of said luminance and said second and third colors by adjusting a first effective sensing area of the micro lens of said first filters of said luminance and a second and third effective sensing areas of said second and third filters of said second and third colors respectfully wherein each of said second and third filters covered by a micro lens.
said color image sensor is configured with a set of desired signal-to-noise ratios of said luminance and said second and third colors by adjusting a first effective sensing area of the micro lens of said first filters of said luminance and a second and third effective sensing areas of said second and third filters of said second and third colors respectfully wherein each of said second and third filters covered by a micro lens.
20. A color image sensor comprising:
at least a first color filter for sensing a luminance from an entire spectrum relevant to said color image sensor.
at least a first color filter for sensing a luminance from an entire spectrum relevant to said color image sensor.
21. The color image sensor of claim 1 further comprising:
a second filter of a second valor and a third filter of a third color wherein said second and third colors correspond two non-overlapping segments of said entire spectrum and the sensing pixels of the said second and third colors have different effective optical sensing areas from that of the pixels of the said first color.
a second filter of a second valor and a third filter of a third color wherein said second and third colors correspond two non-overlapping segments of said entire spectrum and the sensing pixels of the said second and third colors have different effective optical sensing areas from that of the pixels of the said first color.
22. The color image sensor of claim 20 further comprising:
a plurality of first color filters for sensing a luminance from an entire spectrum relevant to said color sensor;
a plurality of second filters of a second color and a plurality of third filter of a third color wherein said second and third colors correspond two non-overlapping segments of said entire spectrum and the sensing pixels of the said second and third colors have different effective optical sensing areas from that of the pixels of the said first color.
a plurality of first color filters for sensing a luminance from an entire spectrum relevant to said color sensor;
a plurality of second filters of a second color and a plurality of third filter of a third color wherein said second and third colors correspond two non-overlapping segments of said entire spectrum and the sensing pixels of the said second and third colors have different effective optical sensing areas from that of the pixels of the said first color.
23. The color image sensor of claim 22 wherein:
said color image sensor having more or an about same number of filters of said first color than said filters of said second color and said filters of said third color.
said color image sensor having more or an about same number of filters of said first color than said filters of said second color and said filters of said third color.
24. The color image sensor of claim 22 wherein:
said filters of said first color and said filters of said second and third colors are configured according to a Bayer tessellation.]
said filters of said first color and said filters of said second and third colors are configured according to a Bayer tessellation.]
25. The color image sensor of claim 22 wherein:
said filters of said first color and said filters of said second and third colors are configured according to a hexagonal tessellation.
said filters of said first color and said filters of said second and third colors are configured according to a hexagonal tessellation.
26. The color image sensor of claim 22 wherein:
said filters of said white color and said filters of said second and third colors are configured according to a YUV422 tessellation.
said filters of said white color and said filters of said second and third colors are configured according to a YUV422 tessellation.
27. A color image sensor of claim 20 wherein:
said first color filter is for sensing a luminance from an entire spectrum of a visible color for a human eye.
said first color filter is for sensing a luminance from an entire spectrum of a visible color for a human eye.
28. The color image sensor of claim 27 further comprising:
a second filter of a second color, and a third filter of a third color wherein said second and third colors are two different primary visible colors for a human eye.
a second filter of a second color, and a third filter of a third color wherein said second and third colors are two different primary visible colors for a human eye.
29. The color image sensor of claim 27 further comprising:
a second filter of a red color, and a third filter of a blue color.
a second filter of a red color, and a third filter of a blue color.
30. The color image sensor of claim 27 further comprising:
a plurality of first color filters for sensing a luminance from an entire spectrum of a color for a human eye;
a plurality of second filters of a second color and a plurality of third filter of a third color wherein said second and third colors are two primary colors and the sensing pixels of the said second and third colors have different effective optical sensing areas from that of the pixels of the said first color.
a plurality of first color filters for sensing a luminance from an entire spectrum of a color for a human eye;
a plurality of second filters of a second color and a plurality of third filter of a third color wherein said second and third colors are two primary colors and the sensing pixels of the said second and third colors have different effective optical sensing areas from that of the pixels of the said first color.
31. The color image sensor of claim 27 wherein:
said color image sensor having more or an about same number of filters of said white color than said filters of said second color and said filters of said third color.
said color image sensor having more or an about same number of filters of said white color than said filters of said second color and said filters of said third color.
32. The color image sensor of claim 27 wherein:
said filters of said white color and said filters of said second and third colors are configured according to a Bayer tessellation.
said filters of said white color and said filters of said second and third colors are configured according to a Bayer tessellation.
33. The color image sensor of claim 27 wherein:
said filters of said white color and said filters of said second and third colors are configured according to a hexagonal tessellation.
said filters of said white color and said filters of said second and third colors are configured according to a hexagonal tessellation.
34. The color image sensor of claim 27 wherein:
said filters of said white color and said filters of said second and third colors are configured according to a YUV422 tessellation.
said filters of said white color and said filters of said second and third colors are configured according to a YUV422 tessellation.
35. The color image sensor of claim 22 wherein:
said color image sensor is configured with a set of desired signal-to-noise ratios of said first color and said second and third colors by adjusting a first area covered by said first filters of said first color and a second and third areas covered by said second and third filters of said second and third colors respectfully.
said color image sensor is configured with a set of desired signal-to-noise ratios of said first color and said second and third colors by adjusting a first area covered by said first filters of said first color and a second and third areas covered by said second and third filters of said second and third colors respectfully.
36. The color image sensor of claim 22 wherein:
said color image sensor is configured with a set of desired signal-to-noise ratios of said first color and said second and third colors by adjusting a first effective sensing area of the micro lens of said first filters of said first color and a second and third effective sensing areas of said second and third filters of said second and third colors respectfully wherein each of said second and third filters covered by a micro lens.
said color image sensor is configured with a set of desired signal-to-noise ratios of said first color and said second and third colors by adjusting a first effective sensing area of the micro lens of said first filters of said first color and a second and third effective sensing areas of said second and third filters of said second and third colors respectfully wherein each of said second and third filters covered by a micro lens.
37. The color image sensor of claim 30 wherein:
said color image sensor is configured with a set of desired signal-to-noise ratios of said luminance and said second and third colors by adjusting a first area covered by said first filters of said luminance and a second and third areas covered by said second and third filters of said second and third colors respectfully.
said color image sensor is configured with a set of desired signal-to-noise ratios of said luminance and said second and third colors by adjusting a first area covered by said first filters of said luminance and a second and third areas covered by said second and third filters of said second and third colors respectfully.
38. The color image sensor of claim 30 wherein:
said color image sensor is configured with a set of desired signal-to-noise ratios of said luminance and said second and third colors by adjusting a first effective sensing area of the micro lens of said first filters of said luminance and a second and third effective sensing areas of said second and third filters of said second and third colors respectfully wherein each of said second and third filters covered by a micro lens.
said color image sensor is configured with a set of desired signal-to-noise ratios of said luminance and said second and third colors by adjusting a first effective sensing area of the micro lens of said first filters of said luminance and a second and third effective sensing areas of said second and third filters of said second and third colors respectfully wherein each of said second and third filters covered by a micro lens.
39. A color image sensor comprising:
a plurality of color filters of different colors wherein tessellation of said color filters of said different colors is configured for achieving substantially a desired signal-to-noise ratio for each of said colors.
a plurality of color filters of different colors wherein tessellation of said color filters of said different colors is configured for achieving substantially a desired signal-to-noise ratio for each of said colors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002460403A CA2460403A1 (en) | 2004-03-10 | 2004-03-10 | Color filter patterns for image sensors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002460403A CA2460403A1 (en) | 2004-03-10 | 2004-03-10 | Color filter patterns for image sensors |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2460403A1 true CA2460403A1 (en) | 2005-09-10 |
Family
ID=34976954
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002460403A Abandoned CA2460403A1 (en) | 2004-03-10 | 2004-03-10 | Color filter patterns for image sensors |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2460403A1 (en) |
-
2004
- 2004-03-10 CA CA002460403A patent/CA2460403A1/en not_active Abandoned
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20040105021A1 (en) | Color filter patterns for image sensors | |
| US11310471B2 (en) | Digital cameras with direct luminance and chrominance detection | |
| US7872681B2 (en) | System and method for a high performance color filter mosaic array | |
| US10032810B2 (en) | Image sensor with dual layer photodiode structure | |
| US20070291982A1 (en) | Camera module | |
| CN105633105B (en) | To minimize the RGBC color filter array patterns of color aliasing | |
| US7745779B2 (en) | Color pixel arrays having common color filters for multiple adjacent pixels for use in CMOS imagers | |
| TWI615033B (en) | Color filter array, image sensor and method for reducing spectral crosstalk | |
| US7414630B2 (en) | Hexagonal color pixel structure with white pixels | |
| US8576313B2 (en) | Color filters and demosaicing techniques for digital imaging | |
| KR100827242B1 (en) | Method and apparatus for image processing | |
| CN101355093B (en) | Color filter arrays and image sensors using the same | |
| TWI600927B (en) | Color filter array patterns for reduction of color aliasing | |
| CN104012085A (en) | Color imaging element | |
| CN104012084B (en) | Color imaging element | |
| EP1575303A1 (en) | Color filter patterns for image sensors | |
| US20220093666A1 (en) | Color filter array apparatus | |
| CA2460403A1 (en) | Color filter patterns for image sensors | |
| JP2005260560A (en) | Color filter pattern for image sensor | |
| CN114424517B (en) | Image sensor, control method, camera component and mobile terminal | |
| TW201405785A (en) | Image sensing device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |