Combined visible and infrared image sensor incorporating a selective infrared filter

Abstract

The present application relates to a combined visible and infrared image sensor incorporating a selective infrared filter. The present invention discloses a pixel array comprising: a green pixel comprising a first green filter and a first clear filter; a red pixel comprising a red filter and a first special filter; a blue pixel comprising a blue filter and a second special filter; and an IR pixel comprising an IR filter and one of a second green filter and a second clear filter, wherein the first special filter suppresses transmission of IR at a stop band centered at 850 nm with a first IR minimum transmission rate, and the second special filter suppresses transmission of IR at the stop band centered at 850 nm with a second IR minimum transmission rate, and wherein the first minimum IR transmission rate is different from the second minimum IR transmission rate.

Description

[0001] CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application is a continuation-in-part of U.S. patent application No. 15 / 620,757 filed on December 6, 2017. Technical Field

[0003] The present invention generally relates to an image sensor system that includes a hybrid image sensor pixel array of visible (VIS) spectrum pixels and infrared (IR) spectrum pixels. More specifically, the image sensor system uses its VIS image sensing capability to produce a VIS color image and uses its IR sensing capability to perform an IR imaging function. Background Art

[0004] Recent developments in the field of image sensing have produced image sensors with security and machine vision applications, including gesture sensing, depth analysis, iris detection, eye tracking, night or low-light vision, etc. In one aspect, these image sensors use traditional VIS spectrum image sensing pixels to produce VIS images. In another aspect, these sensors also use additional IR spectrum pixels to produce IR images. Basically, these sensors have the dual purpose of producing both VIS and IR images.

[0005] Conventionally, such dual-purpose image sensors employ a direct combination design, where the IR sub-sensor is physically juxtaposed close to the VIS sub-sensor. The VIS sub-sensor includes only VIS imaging pixels, and the IR sub-sensor includes only IR imaging pixels. This design provides simplicity, but the VIS and IR sub-sensors inevitably have different vantage points with respect to the imaging target. Therefore, the resulting VIS and IR images not only have different spectra (VIS vs. IR), but also cannot be completely superimposed on each other. This creates difficulties for subsequent image processing. Summary of the invention

[0006] Some embodiments relate to an image sensor system. The image sensor system includes: a pixel array, which includes a plurality of minimal repeating units, each repeating unit includes: a green pixel, which includes a first microlens, a first green filter, a first clear filter, and a first image sensing component; a red pixel, which includes a second microlens, a red filter, a first special filter, and a second image sensing component; a blue pixel, which includes a third microlens, a blue filter, a second special filter, and a third image sensing component; and an IR pixel, which includes a fourth microlens, an IR filter, and a fourth image sensing component.

[0007] Some embodiments relate to a pixel array. The pixel array includes: a green pixel including a first green filter and a first clear filter; a red pixel including a red filter and a first special filter; a blue pixel including a blue filter and a second special filter; an IR pixel including an IR filter and one of a second green filter and a second clear filter; wherein the first special filter suppresses IR transmission at a stop band centered at 850 nm with a first IR minimum transmission rate, and the second special filter suppresses IR transmission at a stop band centered at 850 nm with a second IR minimum transmission rate, and wherein the first minimum IR transmission rate is different from the second minimum IR transmission rate.

[0008] Some embodiments relate to a pixel array. The pixel array includes: a green pixel including a first green filter and a first clear filter; a red pixel including a red filter and a second clear filter; a blue pixel including a blue filter and a special filter; an IR pixel including an IR filter and one of a second green filter and a third clear filter; wherein the special filter suppresses the transmission of IR at the stop band centered at 850 nm with an IR minimum transmission rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Non-limiting and non-exhaustive examples of the present invention are now described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0010] Figure 1A is a schematic diagram showing an exemplary embodiment of a hybrid VIS-IR image sensor system.

[0011] Figure 1B FIG. 1 is a top view of an exemplary VIS-IR image sensor pixel array, showing the smallest repeating unit containing each pixel.

[0012] Figure 2A The characteristic light transmission curve of a VIS-IR bandpass filter is shown as a wavelength versus transmission plot.

[0013] Figure 2B A set of characteristic light transmittance curves for pixels within a VIS-IR pixel array are shown as wavelength versus transmittance plots.

[0014] Figure 2C FIG. 5 is another wavelength versus transmittance plot showing another set of characteristic light transmittance curves for pixels within another VIS-IR pixel array.

[0015] Figure 3A is a side view of a portion of an improved VIS-IR pixel array.

[0016] Figure 3B is another side view of a portion of another improved VIS-IR pixel array.

[0017] Figure 4A is a wavelength versus transmittance plot showing the characteristic light transmittance curve of a selective IR filter.

[0018] Figure 4B is another wavelength versus transmittance plot showing two characteristic light transmittance curves of a selective IR filter before and after modification.

[0019] Figure 5 is a schematic diagram showing an exemplary embodiment of a hybrid VIS-IR image sensor system including a selective IR filter.

[0020] Figure 6 An exemplary method is shown, which includes multiple steps of performing a VIS visual imaging mode and an IR visual imaging mode.

[0021] Fig. 7A An embodiment of a VIS-IR pixel array is shown.

[0022] Figure 7B exhibit Fig. 7A An alternative embodiment of a VIS-IR pixel array.

[0023] Fig. 8A Another embodiment of a VIS-IR pixel array is shown.

[0024] Figure 8B exhibit Fig. 8A An alternative embodiment of a VIS-IR pixel array.

[0025] Fig. 9 2 is a wavelength versus transmission plot showing two characteristic light transmission curves of a selected IR filter or a suppressed IR (SIR) filter.

[0026] Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Those skilled in the art will appreciate that the elements in the drawings are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help improve understanding of the various embodiments of the present invention. Furthermore, in order to facilitate less obstruction of viewing of these various embodiments of the present invention, common but well-understood elements that are useful or necessary in commercially feasible embodiments are generally not depicted. DETAILED DESCRIPTION

[0027] In the following description, numerous specific details are set forth to provide a thorough understanding of the examples. However, one skilled in the art will recognize that the techniques described herein can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other cases, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.

[0028] References throughout this specification to "an example" or "an embodiment" mean that the particular features, structures, or characteristics described in conjunction with the example are included in at least one example of the present invention. Thus, references to "an example" or "an embodiment" in various places throughout this specification do not necessarily all refer to the same example. Furthermore, in one or more examples, particular features, structures, or characteristics may be combined in any suitable manner.

[0029] In this specification, several terms are used. Unless specifically defined herein or the context of their use would clearly suggest otherwise, these terms shall have their ordinary meaning from the art.

[0030] First embodiment: Hybrid VIS-IR image sensor system

[0031] Figure 1A 1 is a schematic diagram of an embodiment of a hybrid VIS-IR image sensor system 100, which includes a main lens 110, a VIS-IR bandpass filter module 120, a VIS-IR image sensor pixel array 130, a controller module 140, a functional logic module 150, and an IR light source module 160. The features and functions of each element are further disclosed herein.

[0032] The main lens 110 focuses the incident light to reach the underlying VIS-IR image sensor pixel array 130 through the VIS-IR bandpass filter module 120. As an example, the main lens 110 is optically transparent and allows all VIS-IR spectrum light to pass therethrough. In other words, the main lens 110 does not have an IR attenuation (IR cutoff) function.

[0033] The VIS-IR bandpass filter module 120 includes a VIS-IR bandpass filter (or filters) 121 attached to the front and / or back sides of a cover glass substrate 122. The cover glass substrate 122 provides mechanical support for the VIS-IR bandpass filter 121 and is preferably optically transparent to allow the full spectrum of both VIS and IR light to pass through. The VIS-IR bandpass filter 121 is preferably a multilayer structure composed of a plurality of alternate layers of transparent inorganic materials (e.g., silicon oxide and titanium oxide) and relies on the principle of destructive interference to block certain spectral bands of incident light while allowing other spectral bands to pass through. In the current exemplary embodiment, as shown in FIG. Figure 1AThe VIS-IR filter 121 described in 1 allows the VIS band and the IR band to pass while blocking other wavelengths. Figure 2A and described in further detail below.

[0034] refer to Figure 2A As an example, a characteristic wavelength versus transmission curve 250 of a VIS-IR bandpass filter 121 is shown. The transmission curve 250 includes a VIS passband 260 for wavelengths of approximately 400 to 650 nanometers (nm) in the VIS range. Note that the shape of the VIS passband 260 has the general form of a rectangle (or close to a trapezoid with two steep sides, i.e., the two base angles of the trapezoid are slightly less than 90 degrees), where the height is close to the height of 100% transmission, and it has almost no leakage outside the passband 260. In other words, for the case of passing a range of wavelengths, the VIS passband 260 is close to an ideal passband. This near-ideal passband characteristic is achieved by using destructive interference produced by multiple layers of transparent inorganic materials. It should be appreciated that this nearly rectangular, leakage-free passband characteristic is different from the bell-shaped and leakage-free passband characteristics produced by the absolute value of organic compounds, such as Figure 2B The points shown in the figure will be further described in detail later in this invention.

[0035] The wavelength-transmittance curve 250 also includes an IR passband 270 at wavelengths of approximately 800 nm to 900 nm in the IR range. Note again that the shape of the IR passband 270 has the form of a steep triangle (with two base angles slightly less than 90 degrees) centered at 850 nm, and that there is almost no leakage outside the IR passband 270, i.e., the IR passband 270 is close to an ideal passband for passing a single wavelength (approximately 850 nm). This near-ideal passband characteristic is again achieved by using destructive interference produced by multiple layers of transparent inorganic materials.

[0036] It should be understood that Figure 2A The characteristic curve 250 in FIG. 1 shows two passbands—VIS passband 260 and IR passband 270. Thus, the VIS-IR filter 121 can be referred to as a dual-bandpass filter that is used to pass incident light within a wide VIS (400 nm to 650 nm) range and a narrow IR range (850 ± 50 nm, or 800 nm to 900 nm). In other embodiments, the IR range can be narrower, for example, 850 ± 30 nm, 850 ± 10 nm, etc. Other wavelengths are blocked by this VIS-IR filter 121.

[0037] It will be appreciated that the above passband values ​​achieved by the destructive interference produced by the multilayer transparent inorganic material depend on the chief ray angle (CRA) of the incident light. This is due to the nature of destructive interference, which involves light reflected from the interface of the multilayer transparent material. As an example, at a CRA of zero degrees (the incident light is perpendicular to the plane of incidence, and contained in the normal plane), the narrow IR passband is approximately 850±50nm, i.e., 800-900nm, as previously disclosed. In contrast, in a CRA of 30 degrees (the light comes in at an angle, and deviates 30 degrees from the normal plane), the IR passband shifts to 825±45nm, or a new range of 780nm to 870nm. This passband dependence on the CRA will have an impact on the image sensor system design, and will be raised again later in this disclosure.

[0038] Reference now Figure 1A , the VIS-IR image sensor pixel array 130 is located below the VIS-IR bandpass filter module 120. The pixel array 130 includes a plurality of VIS and IR pixels, wherein a group of VIS and IR pixels forms a plurality of repeating units 135, which are arranged in a plurality of VIS and IR pixels. Figure 1B FIG. 1 is a portion of a top view of the pixel array 130. The minimum repeating unit is defined as the smallest pixel group that constitutes the entire pixel array. Figure 1B , a minimum repeating unit 135 of the pixel array 130 is composed of green (G) pixels 131, red (R) pixels 132, blue (B) pixels 133, and IR pixels 134 arranged in a square 2×2 pattern.

[0039] Figure 1A A cross-sectional side view of (a representative portion of) pixel array 130 is shown, which includes four individual pixels 131-134. For illustration purposes, only four pixels 131 (G), 132 (R), 133 (B), and 134 (IR) are shown in pixel array 130. In practice, pixel array 130 includes more individual pixels that may have different arrangements. All four pixels 131, 132, 133, and 134 share similar features and are disclosed herein by describing green (G) pixel 131 as a representative pixel.

[0040] The G pixel 131 includes a microlens 131a, a G filter 131b, and an image sensing component 131c. The microlens 131a may be made of a resin material and is primarily used to focus incident light into the pixel 131 itself. The G filter 131b includes an organic material and relies on a chemically based optical absorption principle to pass a light band of a specific wavelength while blocking other wavelengths. In this example, the G filter 131b passes a green band of approximately 450nm to 650nm.

[0041] Figure 2BA set of wavelength versus transmission curves 200 is shown, which includes a G bandpass characteristic curve 220, which corresponds to the G filter 131b. The G curve 220 includes a primary color G bandpass range of approximately 450nm to 650nm, but also has a significant leakage range outside the 450nm to 650nm primary passband, for example, in the 300nm to 450nm range, and also in the near IR and IR ranges of 700nm to 1100nm. The leakage range is attributed to the properties of chemical-based optical absorption. Within the 450nm to 650nm primary color G passband, the appearance of the curve resembles a non-smooth bell curve shape of a partial tilted hole. This non-ideal passband shape is also attributed to chemical-based optical absorption. These characteristics are different from Figure 2A 1 and the related description thereof disclose the nearly ideal characteristics of VIS-IR bandpass filter 121. It should be appreciated that while multilayer filters that rely on destructive interference are suitable for large-scale (millimeter-scale and above) filters such as filter 121, this type of filter design is generally not possible to manufacture for small image sensor pixels (micrometer-scale or smaller), such as pixel 131. In contrast, organic compound filters that rely on chemical-based optical absorption are more suitable for small-scale filters such as filter 131b because the necessary manufacturing processes (e.g., photolithography, spin coating, and drying) can be easily applied to manufacture small, micron (or submicron)-sized filters.

[0042] return Figure 1A , the G pixel 131 includes an image sensing component 131c directly below the G filter 131b. The image sensing component 131c can be a CMOS (complementary metal oxide semiconductor) or CCD (charge coupled device, similar to CMOS but with slight changes) configuration. For example, in a CMOS configuration, the sensing component 131c is made of a silicon substrate (not labeled) in which a photodiode (not shown) is formed. There may also be other components such as a photodiode pinning layer (not shown), a well structure around the photodiode (not shown), and an isolation trench (not shown). These parts generate photoelectric signals based on the photoelectric effect. Various transistor gates (transmission gates, reset gates, source followers, and row selections), floating nodes, and electrical wiring can be used to amplify and relay photoelectric signals to be processed later, but are also not shown.

[0043] Similar to the description of the G pixel 131 described above, the other pixels such as the R pixel 132, the blue pixel 133, and the IR pixel 134 each include their necessary microlenses (132a, 133a, and 134a), filters (132b, 133b, and 134b), and image sensing components (132c, 133c, and 134c). In particular, the filters 131b, 132b, 133b, and 134b each have their own specific characteristic transmission rate curves, namely, the G transmission rate curve 220, the R transmission rate curve 230, the B transmission rate curve 210, and the IR transmission rate curve 240, respectively, as shown in FIG. Figure 2B These filters rely on chemically based optical absorption and their characteristic curves have a leakage range beyond their main spectral passband and a sloped and non-smooth bell-curve shape within their main spectral passband.

[0044] It can be understood that in the above embodiment, the main passband of the G transmittance curve 220 is about 450nm to 650nm (with about 80% peak transmittance); the main passband of the R transmittance curve 230 is about 650nm to 850nm (with about 50% peak transmittance); the main passband of the B transmittance curve 210 is about 380nm to 450nm (with about 70% peak transmittance); and the main passband of the IR transmittance curve 240 is about 800nm ​​to 1000nm (with about 20% peak transmittance), wherein the primary IR passband overlaps with the main passband of the R transmittance curve 230 at about 800nm ​​to 850nm.

[0045] In addition, each of the three VIS transmission curves (G curve 220, R curve 230, and B curve 210) contains one or more leakage passbands outside of its corresponding main spectral passband, for example, a leakage band in the near IR and IR range of about 700nm to 1100nm, with a peak transmission of about 20%. This means that each VIS pixel (R, G, and B) is able to detect IR light to some extent.

[0046] Figure 2C Another alternative set of wavelength versus transmission rate curves 250 is shown. This set of curves 250 is similar to Figure 2B The curve group 200 in FIG. 1 shows the curve group 200, except that the IR curve 260 has a Figure 2B IR curves 240 and 260 both have a primary spectral passband located at approximately 800 nm to 1000 nm, but curve 260 has a peak transmission level of approximately 50%, which is much higher than curve 240's 20%.

[0047] The controller module 140 may be physically and electrically coupled to the VIS-IR image sensor pixel array 130, such as Figure 1A, and operates the hybrid VIS-IR image sensor system to select among a plurality of operating modes. In an embodiment, these modes include (1) a VIS vision mode, which is generally suitable for human vision; and (2) an infrared vision mode, which is generally suitable for security vision, machine vision, and night vision. In this embodiment, the controller module 140 includes a VIS vision mode control submodule 141 that controls the VIS vision mode, and an IR vision mode control submodule 142 that controls the IR vision mode. As an example, the VIS control submodule 141 selectively controls the VIS pixels (e.g., pixels 131, 132, and 133) of the pixel array 130, as shown by the dashed lines connecting the pixels 131, 132, and 133 to the VIS control submodule 141. The IR control submodule 142 selectively controls the IR pixels (e.g., pixel 134) of the pixel array 130, as shown by the dashed lines connecting the pixel 134 to the IR control submodule 142. It can be understood that the above-mentioned control of the pixel array 130 by the controller module 140 is optional.

[0048] Functional logic module 150 receives image signals (not shown) read out from pixel array 130 and processes these signals into images, such as VIS and IR images. VIS pixel signals are used to generate VIS images, and IR signals are used to generate IR images. Image processing is typically performed by an image signal processor (ISP, not shown) as part of functional logic module 150.

[0049] IR light source module 160 operates to illuminate the imaging object with IR spectrum light. In an example, IR light source module 160 is an IR light emitting diode (LED) that emits a relatively narrow spectral range of IR light at approximately 850 nm, with a tolerance of approximately plus or minus 50 nm, 30 nm, 10 nm, or even less. The emitted IR light at 850 ± 50 nm can be continuous, or in rapid, intense pulses (e.g., MHz pulse frequency, with each pulse period on the nanosecond scale). In an example, Figure 1A In the embodiment shown in , during the IR vision mode, the IR control submodule 142 controls the IR light source module 160 to emit IR light pulses of approximately 850 nm.

[0050] The working mode of VIS and IR vision modes is disclosed herein. When the IR mode is selected for machine vision or night vision applications, the IR control submodule 142 is engaged to control the IR light source module 160 to emit rapid pulses of intense IR light of about 850±50nm (tolerance can be less than 50nm, such as 30nm, 10nm, etc.) to illuminate the imaging object. This illuminating IR light has sufficient power to exceed the naturally occurring ambient light. This operating scheme is effective both during the day and at night, but is particularly effective at night (or in a foggy environment) when the ambient natural light is low. The light reflected off the imaging object contains a high percentage of IR spectral components of about 850±50nm (tolerance can be less than 50 nanometers), and other less important spectral components (such as the VIS spectrum) are regarded as noise. Therefore, this reflected light is essentially IR light of about 850±50nm (tolerance can be less than 50 nanometers). The reflected IR light mentioned above passes through the main lens 110 without any significant filtering. When the IR light continues to pass through the VIS-IR dual-bandpass filter module 120, the narrow IR passband 270 (eg, 850±50 nm (tolerance may be less than 50 nm)) is Figure 2B ), which overlaps or completely encompasses the reflected IR spectral range of 850±50 nm (tolerance may be less than 50 nm), allowing most of this reflected IR light to pass through without significant loss to continue to the underlying pixel array 130.

[0051] It will be appreciated that the VIS-IR bandpass filter 120 has a narrow IR passband whose center coincides with the center of the spectral range of the IR light emitted by the light source 160 (e.g., centered at 850 nm). Figure 2A IR passband 270 shown in FIG. 1 is wide enough (i.e., has sufficient tolerance around its center) to permit most of the IR light reflected from the imaging object to pass therethrough. It should be further appreciated that IR passband 270 is not extremely wide to permit too much noise to pass through. As an illustrative example, light source 160 emits IR light having a spectral range of approximately 850±40 nm, and VIS-IR bandpass filter 120 has a corresponding IR passband of approximately 850±50 nm.

[0052] In the IR vision mode, the pixel array 130 essentially functions as an IR sensor array that relies on its IR pixels 134 to generate IR signals. In an embodiment, the VIS pixels 131, 132, and 133 are not engaged to operate in this IR vision mode, and only the IR pixels 134 are controlled by the IR control submodule 142 to participate in the operation. See the IR control submodule 142 for control lines that connect the control module 140 to the pixel array 130. Figure 1A. VIS control submodule 141 is disengaged from VIS pixels 131, 132, and 133. In an alternative where selection by submodules 141 and 142 is optional, both VIS and IR pixels are engaged to operate, but due to the high percentage of the IR component of the light falling on pixel array 130, the signal output is primarily an IR signal. Thus, pixel array 130 essentially functions as an IR sensor. Infrared machine vision mode may be useful in applications such as distance measurement, motion tracking, etc.

[0053] When the VIS vision mode is selected for human vision, the control module 140 may be engaged to inhibit the IR light source module 160 so that it does not emit IR light. The VIS-IR image sensor system 100 now relies on natural lighting to illuminate the imaging object. Incoming natural light ( Figure 1A The optical filter 120 (not shown) typically contains all of the VIS spectrum light, as well as some naturally occurring IR spectrum light. The incoming natural light passes through the primary lens 110 without any significant filtering. As the incident light continues through the VIS-IR dual bandpass filter module 120, a wide 400nm to 650nm VIS passband 260 ( Figure 2B ) allows VIS light in the main spectral range of 400nm to 650nm to pass through it, while the narrow 850±50nm IR passband 270 ( Figure 2B ) allows only a small amount of naturally occurring IR light within a narrow spectral range of 850±50 nm to pass through. Incident light of other spectra, including most IR outside the 850±50 nm range, is filtered out. The unfiltered VIS and IR portions of the incident light continue to reach the underlying pixel array 130.

[0054] Pixel array 130 is used as a conventional RGB sensor array to generate VIS image signals (R, G, and B signals). In an embodiment, VIS control submodule 141 engages VIS pixels 131, 132, and 133 to operate to generate VIS imaging signals, while IR control submodule 142 disengages IR pixel 134 from operation. In an alternative where selection by submodules 141 and 142 is optional, all VIS and IR pixels 131, 132, 133, and 134 are allowed to operate, but the output of IR pixel 134 is not directly used to form a final color image. VIS pixels 131, 132, and 133 generate RGB signals, which are used by function logic module 150 to generate a final color image after conventional image processing steps such as interpolation.

[0055] The infrared component of the filtered incident light does affect the RGB signal to some extent. Figure 2BAs shown in FIG. 1 , the R transmittance curve 230 of the R filter 132b, the G transmittance curve 220 of the G filter 131b, and the B transmittance curve 210 of the B filter 133b each contain a leakage passband in the IR range of about 700nm to 1100nm, which is wider than the 850±50nm passband of the underlying VIS-IR dual passband filter module. Therefore, the RGB signals generated by the VIS pixels 131, 132, and 133 each contain some IR components (at 850±50nm) therein. These are regarded as IR noise.

[0056] Advanced signal processing can be used to remove these IR components, but such removal may only be effective in some cases. As an example, when filters 131b, 132b, 133b, and 134b have light transmission properties such as Figure 2B , IR pixel 134 may be set to operate at the same time as VIS pixels 131, 132, and 133. The IR signal generated by IR pixel 134 may then be used as a correction baseline to subtract the IR component (at 850±50 nm) from the VIS signal generated by VIS pixels 131, 132, and 133 so that the VIS signal may be accurately corrected to remove IR noise.

[0057] However, in some cases, the IR noise cannot be removed accurately. For example, when the filters 131b, 132b, 133b and 134b have Figure 2C The transmission characteristics shown in FIG. 2 are shown in FIG. 2 , where the IR transmission rate curve 260 is Figure 2B 131 , 132 and 133. The IR curve 240 in RGB is more significant (or otherwise different), the IR correction scheme mentioned above will become inaccurate and unreliable. This is because the IR signal generated by IR pixel 134 is very different (e.g., much higher) from the IR component within the RGB signal generated by VIS pixels 131, 132 and 133. This complexity cannot be solved by a simple method. Turn off IR pixel 134 and only engage VIS pixels 131, 132 and 133, because the IR impact of the incident light falling on these VIS pixels will remain unchanged. Therefore, the RGB signal will continue to have some IR noise component, so that the final color image may suffer from IR-related artifacts, such as a reddish tint. This reddish tint is particularly noticeable when the final color image has an innate blue tint (or other cool tint) compared to a red tint (or other warm tint). This is partly because, among VIS pixels 131, 132 and 133, the adverse effect of IR noise on B pixels 133 and G pixels 131 is greater than its effect on R pixels 132. The B and G spectra are farther from the IR spectrum than the R spectrum; however, there is a natural overlap between the R spectrum and the IR spectrum.

[0058] It should be understood that in the above IR noise problem, the culprit IR noise refers to the IR component that passes through the IR passband 270 of the VIS-IR bandpass filter 120, such as Figure 1A and 2A An exemplary IR noise occurs at 850±50 nm (at zero degrees CRA). Another exemplary IR noise occurs at 825±45 nm (at 30 degrees CRA).

[0059] Second embodiment: Improved VIS-IR image sensor system

[0060] To address the above mentioned IR noise issues related to the VIS vision mode of operation, an exemplary first improvement is disclosed herein. The basic concept is to use some means to block incident IR noise through the IR passband 270 (eg, approximately 850±50 nm). Figure 3A The improved VIS-IR image sensor pixel array 300 is superior to the Figure 1A . The improved pixel array 300 has the same components as the original pixel array 130, including microlenses 131a to 134a, filters 131b to 134b, and image sensing components 131c to 134c. In addition, the improved pixel array 300 includes a selective IR cut filter 310, which is superimposed with the VIS filters 131b, 132b and 133b, that is, overlying or underlying (e.g., overlying). The selective IR filter 310 can be a single filter unit overlying a plurality of VIS filters (e.g., a combination of 131b, 132b and 133b), or in a plurality of VIS filters such as 131b, 132b, and 133b. Figure 3B , it can be a single filter overlying a single VIS filter. For this embodiment, each VIS filter has its own corresponding selective IR filter 310 overlying it or underlying it. In addition, the improved pixel array 300 includes an optional IR pass filter 320 that is superimposed with the IR filter 134b, i.e., overlying it or underlying it (e.g., overlying it). The features of the selective IR cut filter 310 and the optional IR pass filter 320 are disclosed herein.

[0061] The selective IR filter 310 is a notched filter, also known as a band-stop filter, which blocks the transmission of light within a certain stop band (e.g., 850±50 nm) while allowing the rest of the spectrum to pass through. The selective IR filter 310 comprises an organic material that relies on chemically based optical absorption principles to block a specific wavelength band of light while passing other wavelengths. The term "selective" indicates that the selective IR filter 310 selectively blocks IR with a relatively narrow stop band, e.g., approximately 850±50 nm.

[0062] Figure 4A The characteristic light transmission rate curve 400 of this selective IR filter 310 is shown. Since the selective IR filter 310 relies on chemical-based optical absorption to block a certain light band from passing, the shape of the stop band 405 is not ideal and has an appearance similar to a partially tilted and rough inverted bell curve shape. It should be understood that although multilayer filters based on destructive interference are suitable for large-size (millimeters and above) filters, such as the filter 121 (such as Figure 1A ), but this filter design is generally not possible to manufacture filters for small image sensor pixels (micrometer scale or less), e.g. Figure 3A Pixels of pixel array 300 in FIG. In contrast, organic compound filters that rely on chemical-based optical absorption are more suitable for this case because the necessary manufacturing processes (e.g., photolithography, spin coating, and drying) can be easily applied to manufacture small, micron (or sub-micron) size filters.

[0063] according to Figure 4A , the characteristic transmission rate curve 400 has a region of a stop band 405, which is located at about 550nm to 950nm. Outside this stop band 405 region, light transmission is relatively high (e.g., 90% to 100%). Within this stop band 405, light transmission is significantly reduced. In addition, at about 850nm, light transmission is completely blocked. The overall effectiveness of the stop band 405 depends on its bandwidth.

[0064] There are many ways to quantitatively characterize the bandwidth of stopband 405. For example, Figure 4A As shown in FIG. 4 , the stopband 405 starts at approximately 550 nm and ends at approximately 950 nm. However, this characterization of the stopband (“apparent stopband”) may not reflect the true effectiveness of the stopband 405 because the reduction in light transmission is not uniform within the stopband 405. In contrast, the half-power evaluation appears to be more accurate in quantifying the effectiveness of the stopband 405. In general, the half-power bandwidth W hp (like Figure 4A ), approximately half of the incident optical signal energy is blocked by the filter. This corresponds to a transmission level of approximately 30% of the transmission rate curve 400. Figure 4A , half-power bandwidth W hp, can be regarded as the effective bandwidth of the stop band 405, where W hp In the range of 810nm to 880nm (width of about 70nm), 850nm is the center point that blocks all light. Since the stop band 405 is skewed to the high wavelength side, the effective bandwidth W of the stop band 405 is used to describe the hp A more accurate way to use three-digit notation is to use 810-850-880 nm, where the three numbers represent the left end, center, and right end of the effective bandwidth area of ​​this stopband, respectively.

[0065] refer to Figure 3A and Figure 3B , which shows the selective IR filter 310 directly overlying the VIS filters 131b, 132b and 133b, and the exemplary incident natural light having the VIS spectrum and the IR noise at 850±50nm first reaches the selective IR filter 310. Figure 4A The stop band 405 depicted in FIG. 4 has an effective bandwidth of 810-850-880 nm, which substantially overlaps with the IR noise range of 800-850-900 nm (alternative notation for 850±50 nm, indicating the left end, center, and right end). In particular, the two centers coincide at 850 nm. In other words, the most effective portion of the stop band coincides with the highest IR noise point. In addition, the left end (800 nm) and the right end (900 nm) of the IR noise range only slightly fall outside the effective bandwidth (810 nm to 880 nm) of the stop band 405. Therefore, the selective IR filter 310 appears to substantially eliminate the effects of IR noise, which would cause a reddish tint to be ultimately produced in the final color image during the VIS human vision mode.

[0066] Go to Figure 3A and 3B IR pass filter 320 in FIG. 1 , it should be understood that this is an optional element. Since the selective IR filter 310 has been added to the VIS filters 131 b, 132 b and 133 b, but not to the IR filter 134 b, the IR filter 134 b requires some planarization to increase the overall thickness. The IR pass filter 320 provides this planarization function. In addition, the IR pass filter 320 can be located just above or below the IR filter 134 b. The IR pass filter contains organic materials suitable for small image sensor pixels (micrometers or less).

[0067] The IR pass filter 320 allows a wide range of IR to pass. Its IR pass range preferably covers the entire IR pass range of its adjacent IR filter 134b, which is depicted as having Figure 2B The characteristic transmission rate curve 240 or Figure 2C260 in FIG. 26A . The IR transfer function of filter 320 can be implemented in a variety of ways. First, IR pass filter 320 can be transparent enough to pass all spectra of VIS and IR (thus making filter 320 an "all pass" filter, which is essentially a non-filter). Second, filter 320 can be a low pass filter to pass only the longer wavelength spectrum in the IR range, e.g., about 700 nm and above. Third, in the case where optional IR pass filter 320 is not implemented at all, the existing IR filter 134b can simply be made thicker (e.g., with an additional thickness substantially equal to the thickness of the selective IR filter 310) to achieve planarization with adjacent VIS filters 131b, 132b, and 133b. There may be other effective options. As one skilled in the art can recognize, different organic materials can be appropriately selected for each option.

[0068] Figure 5 FIG. 5 is a schematic diagram of an improved hybrid VIS-IR image sensor system 500. Figure 1A 1 is substantially similar to the VIS-IR system 100 shown in FIG, but includes a selective IR filter 310 and an optional IR pass filter 320 within the improved pixel array 300. The other components remain the same as the original system 100. The presence of the selective IR filter 310 allows the improved hybrid VIS-IR system 500 to reduce IR noise in its final VIS image when combined in VIS vision mode. Its IR vision mode remains the same as in the original system 100.

[0069] Third embodiment: Further improved VIS-IR image sensor system

[0070] As previously discussed, the VIS-IR filter module 120 is made of multiple layers of transparent material that uses destructive interference to create its passband. Therefore, its passband may shift depending on the chief ray angle (CRA) of the incident light. As a specific example, at a CRA of zero degrees, Figure 2A , is about 850±50 nm, i.e., 800-850-900 nm. In contrast, at a CRA of 30 degrees, the IR passband 270 now becomes 825±45 nm, or 780-825-870 nm. This passband dependence on CRA allows the IR noise to shift with the CRA, thus making the selective IR filter less effective at certain CRA values ​​than other CRA values, as further explained below.

[0071] As previously disclosed, the selective IR filter 310 has an effective blocking bandwidth of 810-850-880 nm, which is suitable for zero-degree CRA incident IR noise at 800-850-900 nm. However, at 30 degree CRA, the IR passband 270 of the VIS-IR filter 120 shifts to 825±45 nm, or 780-825-870 nm, and therefore, the incident IR noise is now shifted to the range of 780-825-870 nm. The present selective IR filter will not be very effective in handling this shifted IR noise. First, the selective IR filter blocking bandwidth center of 850 nm no longer coincides with the shifted IR noise center of 825 nm. More importantly, the left end of the shifted IR noise (780 nm) now falls well outside the left end of the selective IR filter blocking bandwidth (810 nm). This means that at 30 degree CRA, the current selective IR filter 310 will lose some of its effect in reducing IR noise.

[0072] To address the above-mentioned CRA-dependent shift of IR noise, the selective IR filter 310 is configured to filter the IR light by widening the effective bandwidth W of its stop band. hp And be improved. Figure 4B An embodiment of a second improvement to the hybrid VIS-IR system (which is a first improvement to the selective IR filter 310) is described. Figure 4B The original characteristic transmission rate curve 400 of the selective IR filter 310 before modification is shown. Figure 4A 4 is the same as the transmittance curve 400 shown in FIG. The improved characteristic transmittance curve 410 is the characteristic transmittance curve of the improved selective IR filter 310. The improved curve 410 (solid curve) has a wider effective bandwidth than the original curve 400 (dashed curve). In this embodiment, the improved curve 410 has an effective blocking bandwidth of 720-850-880 nm. This extension of the effective bandwidth is achieved by modifying the organic material within the selective IR filter 310.

[0073] The improved blocking bandwidth of 720-850-880 nm is more effective than the pre-improved bandwidth of 810-850-880 nm to filter out incident IR noise. The following table compares the two bandwidths quantitatively.

[0074] Table 1: Comparison of blocking bandwidth of selective IR filters before and after improvement

[0075]

[0076] At zero degrees CRA, the incident IR light noise has a range of 800-850-900nm. The improved selective IR filter stopband of 720-850-880nm captures essentially all of the IR noise range. The stopband center coincides with the center of the noise range at 850nm. The left end of the noise range (800nm) falls completely within the left end of the improved stopband (720nm). Even more impressive is that at 30 degrees CRA, the incident IR light noise has an offset range of 780-825-870nm, and the left end of this offset noise range (780nm) also falls completely within the left end of the improved stopband (720nm). This improved stopband of 720-850-880nm is significantly more favorable than the previous selective IR filter stopband of 810-850-880nm.

[0077] In summary, the pre-existing selective IR filter 310 is improved by expanding its effective IR stopband W hp This allows for improved selective IR filter performance to better handle incident IR noise coming in at different directions (e.g., from 0 to 30 degrees CRA).

[0078] The improved selective IR filter 310 is similarly implemented in the VIS-IR image sensor system 500, as shown in FIG. Figure 5 The previous disclosure still applies, except that the improved selective IR filter 310 now has a wider effective bandwidth (e.g., 720-850-880 nm), and this second improved system 500 can better handle input IR noise at various CRA angles (e.g., from zero to 30 degrees).

[0079] Fourth embodiment: operation method

[0080] Several embodiments disclosed above may utilize the operating methods described herein. Figure 6 An exemplary method 600 is shown, which includes a plurality of steps. The order of some of the steps need not be arranged in chronological order. At step 610, a selection is made to engage the VIS visual mode or the IR visual mode. Step 610 may be performed by Figure 1A The controller module 140 in the embodiment executes to select the VIS mode 141 or the IR mode 142. If the VIS mode 141 is selected to be engaged, as shown in step 620, then in the subsequent step 621, the IR illumination of the imaging object is suppressed. This can be avoided by Figure 1AThe IR light source 160 in the VIS mode is turned on to achieve this. Natural light is used to illuminate the imaging object in this VIS mode. The natural light reflected from the imaging object may include VIS and IR spectral components. In step 622, the reflected natural light is filtered to allow specific VIS and IR bands to pass. For example, the VIS-IR filter 120 allows the wide VIS band 260 and the narrow IR band 270 to pass the VIS and IR components, respectively. Figure 1A and 2A Step 623 is optional, wherein the passed IR band 270 is prevented from reaching the underlying pixel array 130, particularly its VIS pixels 131, 132 and 133. For example, the selective IR filter 310 (see Figure 3A and Figure 5 ) has a stop band 405 (see Figure 4A ), which blocks the IR noise that has passed through the IR band 270. Ultimately, the remaining VIS component of the reflected natural light is used to form a final VIS image that is relatively free of IR noise.

[0081] If the IR mode 142 is selected to be engaged, as shown in step 630, then the imaging object is illuminated using IR lighting in step 631. For example, the IR mode 142 may be engaged. Figure 1A IR light source 160 in the imager is used to emit rapid pulses of IR light toward the imaging object. Due to the relatively high power of the IR pulses, the reflected light has a significant IR component, and the VIS spectrum can be seen as low-level noise. IR mode 142 is suitable for both day and night, and works particularly well in low light conditions (including dark or foggy environments). In step 632, the IR component is allowed to pass through to the underlying pixel array. For example, VIS-IR filter 120 (see Figure 1A ) allows IR band 270 (see Figure 2A ) passes the IR component of the reflected light. Step 633 is optional, wherein the passed IR light is allowed to propagate further to reach the sensing area of ​​the underlying pixel array. For example, IR pass filter 320 allows the IR component to reach imaging element 134c of IR pixel 134 (see Figure 3A and Figure 5 ). Ultimately, infrared components are used to perform infrared vision functions such as distance measurement, object tracking, low-light imaging, etc.

[0082] Fifth embodiment: combination of optical filter and special optical filter

[0083] Fig. 7A Shows something like Figure 3A and 3BThe VIS-IR pixel array 700 includes a green (G) pixel 731, a red (R) pixel 732, a blue (B) pixel 733, and an IR pixel 734. Although the G pixel 731, the R pixel 732, the B pixel 733, and the IR pixel 734 are Fig. 7A , but they can be arranged in a square 2X2 pattern, such as Figure 1B As displayed.

[0084] The pixel array 700 has Figure 1A The same components as the original pixel array 130 include microlenses 731a to 734a (first to fourth microlenses), filters 731b to 734b, and image sensing components 731c to 734c (first to fourth image sensing components). In addition, the pixel array 700 includes special filters 731d to 734d. The special filters 731d to 734d include an IR filter similar to the IR filter 134b, a clear filter (C), and a SIR (suppress IR) filter similar to the selective IR filter 310. The clear filter (C) passes both visible light and IR light. Although Fig. 7A Filters 731b through 734b are shown overlying special filters 731d through 734d, but filters 731b through 734d may underlie special filters 731d through 734d.

[0085] exist Fig. 7A , filters 731b (first G filter) and 734b (second G filter) are similar to G filter 131b, filter 732b is an R filter similar to R filter 132b, and filter 733b is a B filter similar to B filter 133b. Special filter 731d is a first clear filter (C). Special filter 732d (first special filter) is a second clear filter (C). The first and second clear filters pass visible light and IR light. Special filter 733d (second special filter) is a SIR filter similar to selective IR filter 310. Special filter 734d is an IR filter similar to IR filter 134b. In an embodiment, the thickness of filters 731b to 734b may be 0.7 μm, and the thickness of special filters 731d to 734d may be 1.0 μm. Alternatively, filter 734b may be an IR filter similar to IR filter 134b, and special filter 734d may be a third clear filter, such as Figure 7B As shown in .

[0086] Filters 731b, 732b, and 733b each have their own specific characteristic transmission curve, i.e., Figure 2BOr G transmission rate curve 220, R transmission rate curve 230 and B transmission rate curve 210 of 2C. Fig. 7A In the embodiment of FIG. 7 , filter 734b is the same as filter 731b. Figure 7B In the embodiment of FIG. 7 , filter 734 b is an IR filter having Figure 2B The IR transmission rate curve of 240 or Figure 2C The SIR filter 733d is similar to the one having Figure 4A Or the selective IR filter 310 having the characteristic transmission curve 400 of FIG. 4B. The clear filter (C) passes both visible light and infrared light.

[0087] While the selective IR filter 310 (SIR filter 733d) is a notched filter, also known as a band-stop filter, it blocks the transmission of light within a certain stop band (e.g., 850±50nm) and allows the rest of the spectrum to pass through. Figure 4A , the characteristic transmission rate curve 400 has a region of a stop band 405, which is located at about 550nm to 950nm. Outside this stop band 405 region, light transmission is relatively high (e.g., 90% to 100%). Within this stop band 405, light transmission is significantly reduced. In addition, at about 850nm, light transmission is completely or partially blocked. The overall effectiveness of the stop band 405 depends on its bandwidth.

[0088] exist Fig. 8A In another embodiment shown in FIG. 8 , the VIS-IR pixel array 800 of the present invention includes a green (G) pixel 831, a red (R) pixel 832, a blue (B) pixel 833, and an IR pixel 834. Fig. 8A 831, R pixel 832, B pixel 833 and IR pixel 834 are shown in a linear arrangement, but they can be arranged in a square 2×2 pattern, such as Figure 1B As displayed.

[0089] Filters 831b (first G filter) and 834b (second G filter) are similar to G filter 131b, filter 832b is an R filter similar to R filter 132b, and filter 833b is a B filter similar to B filter 113b. Special filter 831d is a first clear filter. Special filter 834d is an IR filter similar to IR filter 134b. Special filter 832d (first special filter) is a special filter SIR1 filter similar to selective IR filter 310, however having an exemplary characteristic transmission rate curve 902 with a first minimum transmission rate 904 at a stop band 905 (e.g., 850±50nm), as shown in FIG. Fig. 9, special filter 833d (second special filter) is a SIR2 filter similar to selective IR cut filter 310, but has an exemplary characteristic transmission rate curve 906 with a second minimum transmission rate 908 at stop band 905 (e.g., 850±50nm), as shown in Fig. 9 In an embodiment, the thickness of filters 831b to 834b may be 0.7 μm, and the thickness of special filters 831d to 834d may be 1.0 μm. Alternatively, filter 834b may be an IR filter similar to IR filter 134b, and special filter 834d may be a clear filter (third clear filter), such as Figure 8B Please note that Figure 8B There is no second clear filter.

[0090] Minimum transmission rate 904 is different from minimum transmission rate 908. The SIR1 filter and the SIR2 filter may be made of different materials or different material compositions.

[0091] In this way, the transmission rate 904 at the stop band 905 (e.g., 850±50 nm) of the special filter 832d (first special filter) for the red pixel 832 is different from the transmission rate 908 at the stop band 905 (e.g., 850±50 nm) of the special filter 833d (second special filter) for the blue pixel 833. Therefore, the ratio (R) of the transmission rate 904 at the stop band 905 (e.g., 850±50 nm) of the special filter 832d (first special filter) to the transmission rate in the pass band 650 to 850 nm of the filter 832b is different from the ratio of the transmission rate 908 at the stop band 905 (e.g., 850±50 nm) of the special filter 833d (second special filter) to the transmission rate in the pass band 380 to 450 nm of the filter 833b (B). This will provide better color balance results, i.e. a better balance between R, G and B.

[0092] In other words, SIR1 / R≠SIR2 / B, where SIR1 is the transmission of IR at the stopband 905 (e.g., 850±50nm) of the special filter at the red pixel, R is the transmission of the red filter at the red pixel in the passband 650nm to 850nm, SIR2 is the transmission of IR at the stopband 905 (e.g., 850±50nm) of the special filter at the blue pixel, and B is the transmission of the blue filter at the blue pixel in the passband 380nm to 450nm. For example, the transmission of the red filter at the red pixel in the passband 650nm to 850nm may be 50% (curve 230), and the transmission of the blue filter at the blue pixel in the passband 380nm to 450nm may be 70% (curve 210). In another embodiment, SIR1 may be the same as SIR2.

[0093] It should be understood that the VIS-IR pixel arrays 700 and 800 may replace Figure 1A The VIS-IR pixel array 130 or Figure 5 The VIS-IR pixel array 300 in the hybrid VIS-IR image sensor system 100 or 500 is formed. The hybrid VIS-IR image sensor system 100 or 500 includes a VIS-IR bandpass filter 121, which has a transmission rate curve including a visible passband of 400nm to 650nm and an IR passband of 800nm ​​to 900nm. The VIS-IR pixel array 700 or 800 can be located below the VIS-IR bandpass filter 121. The hybrid VIS-IR image sensor system operates in a VIS mode or an IR mode. The VIS mode produces a visible image, and the IR mode produces an IR image. The hybrid VIS-IR image sensor system also includes a light source 160 for emitting light in the IR passband of 800nm ​​to 900nm.

[0094] The above description of the illustrated examples of the present invention (including what is described in the Abstract) is not intended to be exhaustive or to limit the present invention to the precise forms disclosed. Although specific examples of the present invention are described herein for illustrative purposes, as those skilled in the art will recognize, various modifications may be made within the scope of the present invention.

[0095] These modifications may be made to the present invention in light of the above detailed description. The terms used in the following claims should not be interpreted as limiting the present invention to the specific examples disclosed in the specification. On the contrary, the scope of the present invention is determined entirely by the appended claims, which should be interpreted according to established principles of claim interpretation.

Claims

1. An image sensor system, comprising: A pixel array comprising a plurality of minimal repeating units, each repeating unit comprising a visible spectrum pixel and an infrared spectrum pixel, wherein Each of the visible spectrum pixel and the infrared spectrum pixel includes an image sensing component and a microlens; Each visible spectrum pixel includes a first filter having a first passband of the visible spectrum; as well as Each infrared spectrum pixel includes a second filter having a second passband of the infrared spectrum; a third optical filter located above the pixel array, the third optical filter having a third passband of the visible spectrum and a fourth passband of the infrared spectrum; a light source emitting light in said infrared spectrum; as well as a controller that controls the image sensor system to operate in a first mode and a second mode, the first mode using the visible spectrum and the second mode using the infrared spectrum; wherein the light source emits light in the infrared spectrum having a wavelength range that at least overlaps with the fourth passband; wherein the wavelength range falls within the fourth passband; wherein at least one visible spectrum pixel further comprises a fourth filter, the fourth filter being superimposed with the first filter; wherein the fourth optical filter has a stop band that overlaps at least with the fourth pass band; wherein at least one infrared spectrum pixel further comprises a fifth filter, the fifth filter being superimposed with the second filter; The fifth optical filter is a low pass filter configured to pass light above 700 nanometers. 2 . The image sensor system of claim 1 , wherein the stopband includes 850 nanometers as its most efficient stopband point. 3 . The image sensor system of claim 2 , wherein the stop band has an effective bandwidth in the range of 720 nanometers to 880 nanometers.

4. An image sensor system, comprising: A pixel array comprising visible spectrum pixels and infrared spectrum pixels, wherein Each visible spectrum pixel is configured to sense light in a first spectral range in the visible spectrum; as well as Each infrared spectrum pixel is configured to sense light in a second spectral range in the infrared spectrum; a filter located above the pixel array, the filter being configured to pass a third spectral range in the visible spectrum and a fourth spectral range in the infrared spectrum, wherein the fourth spectral range is smaller than the second spectral range; a light source emitting light in a fifth spectral range in the infrared spectrum, wherein the fifth spectral range at least overlaps with the fourth spectral range; as well as a controller that controls the image sensor system to selectively operate in a first mode and a second mode, the first mode using the first spectral range and the second mode using the second spectral range; wherein the fifth spectral range falls within the fourth spectral range; wherein at least one visible spectrum pixel is configured to be effectively unaffected by electromagnetic radiation contained within said fourth spectral range; wherein at least one visible spectrum pixel further comprises a first type of filter configured to block electromagnetic radiation contained within the fourth spectral range; wherein the first type of filter is configured to block electromagnetic radiation at 850 nanometers; The first type of filter is configured to block electromagnetic radiation between the spectral range of 720 nanometers and 880 nanometers. 5 . The image sensor system of claim 4 , wherein at least one infrared spectrum pixel further comprises a second type of filter configured to pass electromagnetic radiation in the second spectral range.

6. An image sensor system, comprising: A pixel array comprising a plurality of minimal repeating units, each repeating unit comprising: A green pixel including a first microlens, a first green filter, a first clear filter and a first image sensing component; a red pixel including a second microlens, a red filter, a first special filter and a second image sensing component; a blue pixel including a third microlens, a blue filter, a second special filter and a third image sensing component; an IR pixel comprising a fourth microlens, an IR filter and a fourth image sensing component, The thickness of the first clear filter, the first special filter and the second special filter is 1.0 μm.

7. A pixel array comprising: a green pixel comprising a first green filter and a first clear filter; a red pixel including a red filter and a first special filter; a blue pixel including a blue filter and a second special filter; an IR pixel comprising an IR filter and one of a second green filter and a second clear filter; Wherein the first special filter suppresses IR transmission at a stop band centered at 850 nm at a first IR minimum transmission rate, and the second special filter suppresses IR transmission at a stop band centered at 850 nm at a second IR minimum transmission rate, and wherein the first IR minimum transmission rate is different from the second IR minimum transmission rate. 8 . The pixel array of claim 7 , wherein a ratio of the first IR minimum transmission rate to a red transmission rate of the red filter is different from a ratio of the second IR minimum transmission rate to a blue transmission rate of the blue filter.

9. A pixel array comprising: a green pixel comprising a first green filter and a first clear filter; a red pixel comprising a red filter and a second clear filter; A blue pixel including a blue filter and a special filter; an IR pixel comprising an IR filter and one of a second green filter and a third clear filter; The special filter suppresses IR transmission at a stop band centered at 850 nm with an IR minimum transmission rate.

Images