Nanophoton hyperspectral imaging

Abstract

The invention relates to nanophoton hyperspectral imaging. Image sensor pixels and methods of construction thereof are provided. The image sensor pixel includes a first photodetector, a second photodetector, a first spectral router, and a second spectral router. The first spectral router is positioned over the first photodetector and the second photodetector. The first spectral router is configured to direct incident light in a first subset of a first color wavelength range to the first photodetector and incident light in a second subset of the first color wavelength range to the second photodetector. The second spectral router is positioned above the first spectral router. The second spectral router is configured to direct the incident light in the first subset and the second subset of the first color wavelength range to the first spectral router. The second spectral router is configured to direct incident light in a second color wavelength range to one or more adjacent image sensor pixels.

Description

Technical Field

[0001] This application relates to nanophotonic hyperspectral imaging. Background Art

[0002] Image sensors are used in electronic devices such as cell phones, cameras, and computers to capture images. Specifically, the electronic device is provided with an array of image sensor pixels arranged in a grid pattern. Each image sensor pixel receives incident photons, such as light, and converts these photons into electrical signals. Column circuits are coupled to each column to read out the sensor signals from each image sensor pixel. Summary of the Invention

[0003] For each pixel in an image, a hyperspectral camera captures the light intensity of a large number of continuous spectral bands (typically tens to hundreds). Therefore, each pixel in the image contains a continuous spectrum and can be used to characterize objects in the scene with extremely high precision and detail. The present disclosure provides image sensor pixels, image sensors, and methods that, among other things, provide hyperspectral imaging using nanophotonic light guides (or spectral routers) to separate color wavelength bands into sub-bands.

[0004] The present disclosure provides an image sensor pixel. In one embodiment, the image sensor pixel includes a plurality of photodetectors, a first spectral router, and a second spectral router. The plurality of photodetectors includes at least a first photodetector and a second photodetector. The first spectral router is positioned above at least the first and second photodetectors. The first spectral router is configured to direct incident light within a first subset of a first color wavelength range to the first photodetector. The first spectral router is also configured to direct incident light within a second subset of the first color wavelength range to the second photodetector. The second spectral router is positioned above the first spectral router. The second spectral router is configured to direct the incident light within the first and second subsets of the first color wavelength range to the first spectral router. The second spectral router is configured to direct incident light within the second color wavelength range to one or more adjacent image sensor pixels.

[0005] The present disclosure also provides an image sensor pixel. In one embodiment, the image sensor pixel includes a pixel array and a controller. The pixel array includes an image sensor pixel. The image sensor pixel includes a first photodetector, a second photodetector, a first spectral router, and a second spectral router. The first spectral router is configured to direct incident light within a first subset of a first color wavelength range to the first photodetector. The first spectral router is also configured to direct incident light within a second subset of the first color wavelength range to the second photodetector. The second spectral router is configured to direct incident light within the first color wavelength range to the first spectral router. The second spectral router is also configured to direct incident light within the second color wavelength range to one or more adjacent image sensor pixels in the pixel array. The controller is configured to determine a first light quantity detected by the first photodetector. The controller is also configured to determine a second light quantity detected by the second photodetector.

[0006] The present disclosure also provides a method for constructing an image sensor pixel. The method includes forming a plurality of photodetectors, including at least a first photodetector and a second photodetector. The method also includes forming a first spectral router positioned above at least the first and second photodetectors. The first spectral router is configured to direct incident light within a first subset of a first color wavelength range to the first photodetector. The first spectral router is also configured to direct incident light within a second subset of the first color wavelength range to the second photodetector. The method also includes forming a second spectral router positioned above the first spectral router. The second spectral router is configured to direct incident light within the first and second subsets of the first color wavelength range to the first spectral router. The second spectral router is also configured to direct incident light within the second color wavelength range to one or more adjacent image sensor pixels. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] To describe in detail exemplary implementations, reference will now be made to the accompanying drawings, in which:

[0008] Figure 1A is a block diagram of an example of an imaging system according to some implementations;

[0009] Figure 1B is an illustration of an example of an imaging system incorporated into a vehicle according to some implementations;

[0010] Figure 2 is a partial schematic diagram and a partial block diagram of an example of an image sensor according to some specific implementations;

[0011] Figure 3 is a schematic diagram of an example of circuitry in an image sensor pixel according to some implementations;

[0012] Figure 4A is a diagram of an example of a color pattern separating pixels according to some implementations;

[0013] Figure 4B It is based on some specific implementations Figure 4A a cross-sectional view of a color pattern;

[0014] Figure 5A is a diagram of an example of a red light wavelength range divided into four wavelength subsets according to some implementations;

[0015] Figure 5B is a diagram of an example of a red split pixel configured to detect four subsets of wavelengths according to some implementations;

[0016] Figure 6A is a diagram of an example of a red light wavelength range divided into two wavelength subsets according to some implementations;

[0017] Figure 6B is a diagram of an example of a diagonally arranged red split pixel configured to detect two subsets of wavelengths according to some implementations;

[0018] Figure 6C is a diagram of an example of horizontally arranged red split pixels configured to detect two subsets of wavelengths according to some implementations;

[0019] Figure 6D is a diagram of an example of vertically arranged red split pixels configured to detect two subsets of wavelengths according to some implementations; and

[0020] Figure 7 is a flow chart of an example of a method for constructing an image sensor pixel according to some specific implementations.

[0021] definition

[0022] Various terms are used to refer to specific system components. Different companies may refer to a component by different names—this document is not intended to distinguish between components that differ in name but function identically. In the following discussion and in the claims, the terms "including" and "comprising" are used in an open-ended manner, and therefore, these terms should be interpreted to mean "including, but not limited to..." Additionally, the terms "couple" or "couples" are intended to mean either an indirect connection or a direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection or through an indirect connection via other devices and connections.

[0023] Terms defining altitudes (such as "above," "below," "upper," and "lower") should be positional terms with respect to the direction of light incident on the pixel array and / or image pixels. Light entering should be considered to interact with or pass through objects and / or structures "above" and "above" before interacting with or passing through objects and / or structures "below" or "lower." Therefore, positional terms may not have any relationship to the direction of gravity.

[0024] As used herein, "a," "an," and "the" refer to both singular and plural referents, unless the context clearly indicates otherwise. For example, a "processor" programmed to perform various functions refers to one processor programmed to perform each function, or more than one processor collectively programmed to perform each of the various functions. For clarity, initially referring to "[referent]" and then subsequently referring to "the [referent]" for premise-based purposes should not preclude the fact that the referenced referents may be plural.

[0025] With respect to electrical devices, whether standalone or as part of an integrated circuit, the terms "input" and "output" refer to electrical connections to the electrical device and should not be construed as verbs requiring operation. For example, a differential amplifier such as an operational amplifier may have a first differential input and a second differential input, and these "inputs" define the electrical connections to the operational amplifier and should not be construed as requiring signal inputs to the operational amplifier.

[0026] "Light" or "color" shall refer to visible light in the range of about 380 nanometers to 700 nanometers. "Light" or "color" shall also refer to light in the range of 700 nanometers to 800 nanometers, as well as invisible light, such as infrared light in the range of about 800 nanometers to 1 millimeter. "Light" or "color" shall also refer to invisible light, such as ultraviolet light in the range of about 100 nanometers to 400 nanometers.

[0027] “Controller” shall mean, alone or in combination, an individual circuit component, an application specific integrated circuit (ASIC), one or more microcontrollers with control software, a reduced instruction set computer (RISC) with control software, a digital signal processor (DSP), one or more processors with control software, a programmable logic device (PLD), a field programmable gate array (FPGA), or a programmable system on a chip (PSOC) that is configured to read inputs and drive outputs in response to those inputs. DETAILED DESCRIPTION

[0028] The following discussion relates to various implementations of the present invention. While one or more of these implementations may be preferred, the disclosed implementations should not be interpreted or otherwise used to limit the scope of the present disclosure, including the claims. Furthermore, those skilled in the art should understand that the following description has broad application, and that the discussion of any implementation is merely an example of that implementation and is not intended to limit the scope of the present disclosure, including the claims, to that implementation.

[0029] Various examples relate to image sensor pixels, image sensors, and related methods. More specifically, at least some examples relate to image sensor pixels and imaging systems that provide hyperspectral imaging. Even more specifically, various examples relate to splitting pixels that use nanophotonic light guides (or spectral routers) to separate color wavelength bands into sub-bands. The description now turns to exemplary systems to guide the reader.

[0030] Figure 1A An example of an imaging system 100 is shown. Specifically, the imaging system 100 can be a portable electronic device with imaging capabilities, such as a camera, a cellular phone, a tablet computer, a webcam, a video camera, a video surveillance system, or a video gaming system. In other cases, the imaging system 100 can be an automotive imaging system. Figure 1A The imaging system 100 shown in FIG. 1 includes a camera module 102 that can be used to convert incoming light into digital image data. The camera module 102 can include one or more lenses 104 and one or more corresponding image sensors 106. The lenses 104 can include fixed and / or adjustable lenses. During an image capture operation, light from a scene can be focused by the lenses 104 onto the image sensors 106. The image sensors 106 can include circuitry for converting analog pixel data into corresponding digital image data, which is provided to an imaging controller 108. If desired, the camera module 102 can be provided with an array of lenses 104 and a corresponding array of image sensors 106.

[0031] The imaging controller 108 may include one or more integrated circuits. The imaging circuitry may include image processing circuitry, a microprocessor, and storage devices, such as random access memory and non-volatile memory. The imaging controller 108 may be implemented using components separate from the camera module 102 and / or components forming part of the camera module 102 (e.g., circuitry forming part of the image sensor 106). The imaging controller 108 may be used to process and store digital image data captured by the camera module 102. The processed image data may be provided to external equipment, such as a computer, an external display, or other device, using wired and / or wireless communication paths coupled to the imaging controller 108, as desired.

[0032] Figure 1B Another example of an imaging system 100 is shown. Figure 1B The imaging system 100 shown in FIG includes an automobile or vehicle 110. The vehicle 110 is illustratively shown as a passenger vehicle, but the imaging system 100 can be other types of vehicles, including commercial vehicles, on-road vehicles, and off-road vehicles. Commercial vehicles can include buses and tractor-trailer vehicles. Off-road vehicles can include tractors and crop harvesting equipment. Figure 1B In the example embodiment, vehicle 110 includes a front-view camera module 102 configured to capture images of a scene in front of vehicle 110. Such a front-view camera module 102 can be used for any suitable purpose, such as lane keeping assist, collision warning systems, cruise control systems, autonomous driving systems, and proximity detection. Example vehicle 110 also includes a rear-view camera module 102 configured to capture images of a scene behind vehicle 110. Such a rear-view camera module 102 can be used for any suitable purpose, such as collision warning systems, reverse video, autonomous driving systems, proximity detection, monitoring the position of overtaking vehicles, and backing up. Vehicle 110 may also include an interior-view camera module 102 configured to capture images of a scene inside vehicle 110. Such an interior-view camera module 102 can be used for any suitable purpose, such as an in-cabin driver monitoring system (DMS) and a driver and occupant monitoring system (DOMS). Vehicle 110 also includes side-view camera modules 102 configured to capture images of a scene beside vehicle 110. Such side-view camera modules can be used for any suitable purpose, such as blind spot monitoring, collision warning systems, autonomous driving systems monitoring the position of overtaking vehicles, lane change detection, and proximity detection. In the case where imaging system 100 is a vehicle, imaging controller 108 can be a controller of vehicle 110. Next, we will discuss image sensor 106 of camera module 102 in more detail.

[0033] Figure 2 An example of an image sensor 106 is shown. Specifically, Figure 2 The image sensor 106 is shown to include a substrate 200 of a semiconductor material (e.g., silicon) encapsulated within a package to produce a packaged semiconductor device or packaged semiconductor product. Bond pads or other connection points of the substrate 200 are coupled to terminals of the image sensor 106, such as a serial communication channel 202 coupled to a terminal 204 and a capture input 206 coupled to a terminal 208. Additional terminals, such as a ground terminal, a common terminal, or a power supply terminal, may be present, but these are omitted to avoid overly complicating the drawing. While a single example of the substrate 200 is shown, in other cases, multiple substrates may be combined to form the image sensor 106 to form a multi-chip module.

[0034] Image sensor 106 includes a pixel array 210 that includes a plurality of image sensor pixels 212 arranged in rows and columns. Pixel array 210, which is one example of a "pixel array," may include, for example, hundreds or thousands of rows and hundreds or thousands of columns of image sensor pixels 212. Control and readout of pixel array 210 may be implemented by an image sensor controller 214 coupled to a row controller 216 and a column controller 218. Row controller 216 may receive a row address from image sensor controller 214 and provide corresponding row control signals to image sensor pixels 212, such as reset, row select, charge transfer, dual conversion gain, and readout control signals. The row control signals may be conveyed via one or more conductors, such as row control paths 220.

[0035] Column controller 218 may be coupled to pixel array 210 via one or more conductors, such as column lines 222. Column controllers may sometimes be referred to as column control circuitry, readout circuitry, or column decoders. Column lines 222 may be used to read out image signals from image sensor pixels 212 and to provide bias currents and / or bias voltages to image sensor pixels 212. If desired, during a pixel readout operation, a row of pixels in pixel array 210 may be selected using row controller 216, and image signals generated by image sensor pixels 212 in that pixel row may be read out along column lines 222.

[0036] Column controller 218 may include sample-and-hold circuitry for sampling and temporarily storing image signals read out from pixel array 210, amplifier circuitry, analog-to-digital conversion (ADC) circuitry, bias circuitry, column memory, latch circuitry for selectively enabling or disabling column circuitry, or other circuitry coupled to one or more pixel columns in pixel array 210 for operating image sensor pixels 212 and for reading out image signals from image sensor pixels 212. The ADC circuitry in column controller 218 may convert analog pixel values ​​received from pixel array 210 into corresponding digital image data. Column controller 218 may provide the digital image data to image sensor controller 214 and / or imaging controller 108 (e.g., via serial communication channel 202). Figure 1A ).

[0037] Figure 3 An example of circuitry in one of image sensor pixels 212 is shown. Image sensor pixel 212 may have Figure 3 The image sensor pixels shown may have fewer components, additional components, or different components in different configurations. Specifically, Figure 3Each of the image sensor pixels 212 is shown to include a photodetector 302 (e.g., a photodiode). A pixel positive supply voltage, such as a supply voltage VAAPIX, may be provided at a positive supply terminal 304. A ground supply voltage, such as a reference voltage Vss, may be provided at a ground terminal 306. Incident light is collected by the photodetector 302. The photodetector 302 converts this light into electrical charge.

[0038] Prior to acquiring an image, a reset control signal RST may be asserted. The reset control signal RST turns on the reset transistor 308 and resets the charge storage (CS) node 310 to a voltage equal to or close to the supply voltage VAAPIX. The reset control signal RST may then be deasserted, turning off the reset transistor 308. After the reset process is complete, the transfer gate control signal TX may be asserted to turn on the transfer transistor 312. When the transfer transistor 312 is turned on, charge generated by the photodetector 302 in response to incoming light is transferred to the charge storage node 310. The charge storage node 310 exhibits a capacitance that can be used to store charge that has been transferred from the photodetector 302. Signals associated with the charge stored in the charge storage node 310 are buffered by the source follower transistor 314. The row select transistor 316 connects the source follower transistor 314 to one of the column lines 222.

[0039] When it is desired to read out the value of the charge stored in the charge storage node 310, the control signal RS is asserted. The readout value may be, for example, the value of the charge storage node 310 represented by the signal at the source terminal S of the source follower transistor 314. When the control signal RS is asserted, the row select transistor 316 turns on and produces an output signal Vout on the output path 318 that represents the magnitude of the charge stored in the charge storage node 310. The output signal Vout is an example of a "pixel signal." When the control signal RS is asserted, one of the column lines 222 may be used to route the output signal Vout from the image sensor pixel 212 to a readout circuit, such as Figure 2 Column controller 218 in.

[0040] Figure 4A A diagram illustrating an example of a color pattern 400 of separated pixels is shown. Specifically, color pattern 400 includes a red separated pixel 402, a first green separated pixel 404, a second green separated pixel 406, and a blue separated pixel 408 arranged in a two-by-two grid. Other grid patterns are possible, such as a one-by-four grid. Other color patterns are also possible, such as red-yellow-yellow-cyan. Red separated pixel 402 is an example of an "image sensor pixel." Figure 4AThe illustrated red separated pixel 402 includes a first red photodetector 410, a second red photodetector 412, a third red photodetector 414, and a fourth red photodetector 416 arranged in a two-by-two grid. In the illustrated example, the four photodetectors of the red separated pixel 402 are adjacent to each other, but in other cases, one or more additional layers, such as an oxide layer or a deep trench isolation (DTI) structure, may reside between the four photodetectors. Figure 4A The illustrated first green separated pixel 404 includes a first green photodetector 418, a second green photodetector 420, a third green photodetector 422, and a fourth green photodetector 424 arranged in a two-by-two grid. Similar discussion regarding the second green separated pixel 406 and the blue separated pixel 408 (each of which may be configured in the same or similar manner) is omitted to avoid unduly lengthening the description.

[0041] Figure 4B Shown along Figure 4A 4B-4B is a cross-sectional view of the color pattern 400. Specifically, Figure 4B The red split pixel 402 is shown to also include a red spectrum router 426 positioned above a first red photodetector 410 and a second red photodetector 412. The first red photodetector 410 is an example of a "first photodetector." The second red photodetector 412 is an example of a "second photodetector." Although Figure 4B Not visible in the cross-sectional view of , but the red spectrum router 426 is also positioned above the third red photodetector 414 and the fourth red photodetector 416. The third red photodetector 414 is an example of a "third photodetector." The fourth red photodetector 416 is an example of a "fourth photodetector." Figure 4B In the example shown, the red spectrum router 426 abuts the first red photodetector 410 and the second red photodetector 412 , but in other cases, one or more additional layers, such as an oxide layer or a planarization layer, may reside between the first and second red photodetectors.

[0042] Figure 4B It is also shown that the first green split pixel 404 also includes a green spectrum router 428 positioned above the first green photodetector 418 and the second green photodetector 420. The first green photodetector 418 is an example of a "third photodetector". The second green photodetector 420 is an example of a "fourth photodetector". Although Figure 4B Not visible in the cross-sectional view of , the green spectrum router 428 is also positioned above the third green photodetector 422 and the fourth green photodetector 424. Figure 4BIn the example shown, the green spectrum router 428 abuts the first green photodetector 418 and the second green photodetector 420 , but in other cases, one or more additional layers, such as an oxide layer or a planarization layer, may reside between the first and second green photodetectors.

[0043] Figure 4B Also shown is a spectrum router 430 positioned above the red spectrum router 426 and the green spectrum router 428. Figure 4B In the example shown, spectrum router 430 is adjacent to red spectrum router 426 and green spectrum router 428, but in other cases, one or more additional layers (such as oxide layers or planar layers) may reside between the red and green spectrum routers.

[0044] A spectral router (or nanophotonic light guide) is an optical structure that receives photons incident on an upper surface. The spectral router then redirects the photons from the upper surface to the underlying photosensitive region of the photodiode. Spectral router 430 is an example of a "second spectral router." Spectral router 430 is configured to direct incident light in the red wavelength range to red spectral router 426. For example, the portion of spectral router 430 positioned above red separation pixel 402 is configured to pass incident light in the red wavelength range (such as between approximately 625 nanometers and 750 nanometers). For purposes of discussion, consider red light entering red separation pixel 402. An example of red light is shown in FIG. Figure 4B 4 is shown by arrow 432. Red light initially strikes the portion of the spectrum router 430 positioned above the red separation pixel 402, which passes the red light to the red spectrum router 426 of the red separation pixel 402. Additionally, the portion of the spectrum router 430 positioned above the first green separation pixel 404 is configured to direct incident light in the red wavelength range to the red spectrum router 426 of the red separation pixel 402. For purposes of discussion, consider red light entering the first green separation pixel 404. An example of red light is shown in FIG. Figure 4B This is shown by arrow 434. The red light initially strikes the portion of the spectral router 430 positioned above the first green split pixel 404, which directs the red light to the red spectral router 426 of the red split pixel 402.

[0045] The spectral router 430 is also configured to direct incident light in the green wavelength range to the green spectral router 428. For example, the portion of the spectral router 430 positioned above the first green separation pixel 404 is configured to pass incident light in the green wavelength range (such as between approximately 495 nanometers and 570 nanometers). For the purposes of discussion, consider green light entering the first green separation pixel 404. An example of green light is shown in FIG. Figure 4B404, which passes the green light to the green spectrum router 428 of the first green separation pixel 404. In addition, the portion of the spectrum router 430 positioned above the red separation pixel 402 is configured to direct incident light in the green wavelength range to the green spectrum router 428 of the first green separation pixel 404. For the purpose of discussion, consider green light entering the red separation pixel 402. An example of green light is shown in FIG. Figure 4B 4 is shown by arrow 438. The green light initially strikes the portion of spectral router 430 positioned above red split pixel 402, which directs the green light to green spectral router 428 of first green split pixel 404.

[0046] The red spectrum router 426 is an example of a "first spectrum router." The red spectrum router 426 is configured to direct incident light in a first subset (or sub-band) of the red wavelength range to the first red photodetector 410. For example, the portion of the red spectrum router 426 positioned above the first red photodetector 410 is configured to pass incident light in the first subset of the red wavelength range. For the purposes of discussion, consider 660 nanometer light entering the red spectrum router 426 above the first red photodetector 410. The example of 660 nanometer light is Figure 4B 4. The 660 nm light initially strikes the portion of the red spectrum router 426 positioned above the first red photodetector 410, which directs the 660 nm light to the first red photodetector 410. Furthermore, the portion of the red spectrum router 426 positioned above the first red photodetector 410 is configured to direct incident light outside of the first subset of the red wavelength range to one or more adjacent red photodetectors. For purposes of discussion, consider 700 nm light entering the red spectrum router 426 above the first red photodetector 410. An example of 700 nm light is shown in FIG. Figure 4B 442. The 700 nanometer light initially strikes the portion of red spectrum router 426 positioned above first red photodetector 410, which directs the 700 nanometer red light to second red photodetector 412.

[0047] The red spectrum router 426 is also configured to direct incident light in a second subset (or sub-band) of the red wavelength range to the second red photodetector 412. For example, the portion of the red spectrum router 426 positioned above the second red photodetector 412 is configured to pass incident light in the second subset of the red wavelength range. For the purposes of discussion, consider 705 nanometer light entering the red spectrum router 426 above the second red photodetector 412. The example of 705 nanometer light is Figure 4B 44. The 705 nm light initially strikes the portion of the red spectrum router 426 positioned above the second red photodetector 412, which directs the 705 nm light to the second red photodetector 412. Furthermore, the portion of the red spectrum router 426 positioned above the second red photodetector 412 is configured to direct incident light outside of the second subset of the red wavelength range to one or more adjacent red photodetectors. For purposes of discussion, consider 670 nm light entering the red spectrum router 426 above the second red photodetector 412. An example of 670 nm light is shown in FIG. Figure 4B 446. The 670 nm light initially strikes the portion of red spectrum router 426 positioned above second red photodetector 412, which directs the 670 nm red light to first red photodetector 410.

[0048] In some embodiments, the red spectrum router 426 is configured to separate red light into four subsets of the red wavelength range. For example, Figure 5A It is a graph showing the red wavelength range. Figure 5A Also shown are examples of four subsets of the red wavelength range into which red spectrum router 426 may separate red light. Figure 5B 402 is a diagram showing an example of a red separated pixel 402. Figure 5BAs shown, the red spectrum router 426 can direct incident light in a first subset of the red wavelength range to the first red photodetector 410, the incident light in a second subset of the red wavelength range to the second red photodetector 412, the incident light in a third subset of the red wavelength range to the third red photodetector 414, and the incident light in a fourth subset of the red wavelength range to the fourth red photodetector 416. In some implementations, the red spectrum router 426 is configured to separate the red light into four subsets of substantially equal size. For example, the red spectrum router 426 can direct incident light having a wavelength between 625 nanometers and 656 nanometers to the first red photodetector 410, the incident light having a wavelength between 657 nanometers and 688 nanometers to the second red photodetector 412, the incident light having a wavelength between 689 nanometers and 720 nanometers to the third red photodetector 414, and the incident light having a wavelength between 721 nanometers and 750 nanometers to the fourth red photodetector 416. In other specific implementations, the red spectrum router 426 is configured to separate the red light into four subsets of different sizes. For example, the red spectrum router 426 may direct incident light having a wavelength between 625 nanometers and 639 nanometers to the first red photodetector 410, incident light having a wavelength between 640 nanometers and 687 nanometers to the second red photodetector 412, incident light having a wavelength between 688 nanometers and 735 nanometers to the third red photodetector 414, and incident light having a wavelength between 736 nanometers and 750 nanometers to the fourth red photodetector 416.

[0049] In some embodiments, the red spectrum router 426 is configured to separate red light into two subsets of the red wavelength range. For example, Figure 6A It is a graph showing the red wavelength range. Figure 6A Also shown are examples of two subsets of the red wavelength range into which red spectrum router 426 may separate red light. Figure 6B 、 Figure 6C and Figure 6D 4 is a diagram of an example of red separated pixels 402 arranged diagonally, horizontally and vertically. Figure 6B As shown, red spectrum router 426 may direct incident light in a first subset of the red wavelength range to first red photodetector 410 and fourth red photodetector 416 , and direct incident light in a second subset of the red wavelength range to second red photodetector 412 and third red photodetector 414 . Figure 6Bis an example in which the first red photodetector 410 is positioned parallel to the fourth red photodetector 416 , and the second red photodetector 412 is positioned parallel to the third red photodetector 414 .

[0050] In some implementations, red spectrum router 426 is configured to separate red light into two subsets of substantially equal size. For example, red spectrum router 426 may direct incident light having a wavelength between 625 nanometers and 687 nanometers to first red photodetector 410 and fourth red photodetector 416, and direct incident light having a wavelength between 688 nanometers and 750 nanometers to second red photodetector 412 and third red photodetector 414. In other implementations, red spectrum router 426 is configured to separate red light into two subsets of different size. For example, red spectrum router 426 may direct incident light having a wavelength between 625 nanometers and 700 nanometers to first red photodetector 410 and fourth red photodetector 416, and direct incident light having a wavelength between 701 nanometers and 750 nanometers to second red photodetector 412 and third red photodetector 414.

[0051] The green spectrum router 428 is an example of a “third spectrum router.” The green spectrum router 428 is configured to direct different sub-wavelengths within the green wavelength range to different photodetectors in the first green split pixel 404. Similar discussions regarding the second green split pixel 406 and the blue split pixel 408 (each of which may be configured in the same or similar manner) are omitted to avoid unduly lengthening the description.

[0052] Conventional hyperspectral image sensors require multiple exposures to generate a multispectral image. However, the image sensor controller 214 is configured to determine the amount of incident light detected by each photodetector in each separated pixel of the pixel array 210 during each exposure. Thus, the image sensor 106 generates a multispectral image from a single exposure and more quickly than conventional sensors. Furthermore, the image sensor controller 214 can combine the amounts of light detected by different photodetectors to determine color information. For example, the green photodetectors in the first green separated pixel 404 and the second green separated pixel 406 can detect a certain amount of yellow light, which is a subset in the upper portion of the green wavelength range. Therefore, the image sensor controller 214 can determine the amount of yellow light by combining: (i) the amount of light detected by the photodetectors in the first green separated pixel 404 and the second green separated pixel 406, which are configured to detect a subset in the upper portion of the green wavelength range; and (ii) the amount of light detected by the photodetector in the red separated pixel 402, which is configured to detect a subset in the lower portion of the red wavelength range.

[0053] In some implementations, the image sensor controller 214 combines the light detected by only some of the photodetectors in the separate cells. Figure 5A and Figure 5B In the configuration of the red separation pixel 402 discussed, the first red photodetector 410 may detect some orange light because the subset of the red wavelength range detected by the first red photodetector 410 is close to the orange wavelength range. Therefore, when characterizing the red light detected by the red separation pixel 402, the image sensor controller 214 may ignore the amount of light detected by the first red photodetector 410 and only use the amount of light detected by the other three red photodetectors in the red separation pixel 402.

[0054] In some implementations, the image sensor controller 214 is configured to determine the total amount of incident light in the color wavelength range detected by the split pixel by combining the amount of light detected by each of the four photodetectors in the split pixel. For example, the image sensor controller 214 can determine the total amount of red light detected by the red split pixel 402 by combining the amount of light detected by each of the four photodetectors in the red split pixel 402. Thus, in addition to performing hyperspectral imaging, the image sensor 106 can also be used as a conventional RGGB sensor without having to change the structure of the image sensor pixel 212.

[0055] Figure 7 is a flow chart of an example of a method 700 for constructing an image sensor pixel according to some specific implementations. Figure 7, and are described as a series of operations. However, these operations may be performed in various orders and / or simultaneously, and / or in conjunction with other actions not presented or described herein. At block 702, a plurality of photodetectors are formed. The plurality of photodetectors includes at least a first photodetector and a second photodetector. For example, red separation pixel 402 is formed from a plurality of photodetectors including at least a first red photodetector 410 and a second red photodetector 412. At block 704, a first spectral router is formed. The first spectral router is positioned above at least the first and second photodetectors. For example, red spectral router 426 is formed above at least the first and second red photodetectors 410 and 412. The first spectral router is configured to direct incident light within a first subset of a first color wavelength range to the first photodetector. For example, red spectral router 426 is configured to direct incident light within the first subset of the red wavelength range to first red photodetector 410. The first spectral router is also configured to direct incident light within a second subset of the first color wavelength range to the second photodetector. For example, the red spectral router 426 is configured to direct incident light in the second subset of the red wavelength range to the second red photodetector 412. At block 706, a second spectral router is formed. The second spectral router is positioned above the first spectral router. For example, the spectral router 430 is formed on the red spectral router 426. The second spectral router is configured to direct incident light in the first and second subsets of the first color wavelength range to the first spectral router. For example, the spectral router 430 is configured to direct incident light in the first and second subsets of the red wavelength range to the red spectral router 426. The second spectral router is also configured to direct incident light in the second color wavelength range to one or more adjacent image sensor pixels. For example, the spectral router 430 is configured to direct incident light in the green wavelength range to the first green separation pixel 404 and the second green separation pixel 406.

[0056] Many electrical connections in the drawings are shown as directly coupled without intervening devices, but are not explicitly described as such in the description above. However, for electrical connections shown in the drawings without intervening devices, this paragraph should serve as an antecedent basis for the claims to refer to any electrical connection as "directly coupled."

[0057] The above discussion is intended to illustrate the principles of the present invention and various specific implementations. Once the above disclosure is fully understood, many variations and modifications will become apparent to those skilled in the art. The following claims are interpreted as intending to include all such variations and modifications.

Claims

1. An image sensor pixel, comprising: a plurality of photodetectors, the plurality of photodetectors comprising at least a first photodetector and a second photodetector; a first spectral router positioned above at least the first photodetector and the second photodetector, wherein the first spectral router is configured to: directing incident light in a first subset of a first color wavelength range to the first photodetector, and directing incident light in a second subset of the first color wavelength range to the second photodetector; and a second spectrum router, located above the first spectrum router and configured to: directing the incident light in the first subset and the second subset of the first color wavelength range to the first spectral router, and Incident light in the second color wavelength range is directed to one or more adjacent image sensor pixels.

2. The image sensor pixel of claim 1 , wherein the plurality of photodetectors further comprises a third photodetector and a fourth photodetector, wherein the first spectral router is further positioned above the third photodetector and the fourth photodetector, and wherein the first photodetector, the second photodetector, the third photodetector, and the fourth photodetector are arranged in a two-by-two grid.

3. The image sensor pixel of claim 2 , wherein the first spectral router is further configured to: directing incident light in a third subset of the first color wavelength range to the third photodetector, and Incident light in a fourth subset of the first color wavelength range is directed to the fourth photodetector.

4. The image sensor pixel of claim 2 , wherein the first spectral router is further configured to: directing the incident light in the second subset of the first color wavelength range to the third photodetector, and The incident light in the first subset of the first color wavelength range is directed to the fourth photodetector. 5 . The image sensor pixel of claim 4 , wherein the first photodetector is positioned parallel to the fourth photodetector, and wherein the second photodetector is positioned parallel to the third photodetector. 6 . The image sensor pixel of claim 1 , wherein the first color wavelength range is for red, and wherein the second color wavelength range is for green.

7. An image sensor comprising: A pixel array, the pixel array comprising image sensor pixels, the image sensor pixels comprising: The first photodetector, The second photodetector, A first spectrum router is configured to: directing incident light in a first subset of a first color wavelength range to the first photodetector, and directing incident light in a second subset of the first color wavelength range to the second photodetector, and A second spectrum router, wherein the second spectrum router is configured to: directing incident light in the first color wavelength range to the first spectrum router, and directing incident light in a second color wavelength range to one or more adjacent image sensor pixels in the pixel array; and A controller configured to: determining a first amount of light detected by the first photodetector, and A second amount of light detected by the second photodetector is determined.

8. The image sensor of claim 7, wherein the image sensor pixel is a first image sensor pixel, wherein the pixel array further comprises a second image sensor pixel, the second image sensor pixel comprising: The third photodetector, a fourth photodetector, and A third spectrum router, wherein the third spectrum router is configured to: directing incident light of a first subset of the second color wavelength range to the third photodetector, and directing incident light of a second subset of the second color wavelength range to the fourth photodetector, The second spectrum router is further configured to route the incident light in the second color wavelength range to the third spectrum router.

9. The image sensor according to claim 8, wherein the controller is further configured to: determining a third amount of light detected by the third photodetector, determining a fourth amount of light detected by the fourth photodetector, and The amount of light of a third color is determined by combining the first light amount and the third light amount.

10. The image sensor of claim 7, wherein the image sensor pixel further comprises a third photodetector and a fourth photodetector, and wherein the controller is further configured to: determining a third amount of light detected by the third photodetector, and A fourth amount of light detected by the fourth photodetector is determined. 11 . The image sensor according to claim 10 , wherein the controller is further configured to determine a total light amount in the first color wavelength range by combining the first light amount, the second light amount, the third light amount, and the fourth light amount.

12. The image sensor according to claim 10, wherein the first spectral router is further configured to: directing incident light of a third subset of the first color wavelength range to the third photodetector, and Incident light of a fourth subset of the first color wavelength range is directed to the fourth photodetector.

13. The image sensor according to claim 10, wherein the first spectral router is further configured to: directing the incident light of the second subset of the first color wavelength range to the third photodetector, and The incident light of the first subset of the first color wavelength range is directed to the fourth photodetector.

14. The image sensor of claim 13, wherein the first photodetector is positioned diagonally adjacent to the fourth photodetector, and wherein the second photodetector is positioned diagonally adjacent to the third photodetector.

15. The image sensor of claim 7, wherein the first color wavelength range is between 625 nanometers and 750 nanometers, and wherein the second color wavelength range is between 495 nanometers and 570 nanometers.

16. The image sensor of claim 7, wherein the imaging sensor is included in at least one selected from the group consisting of: an automobile, a vehicle, a camera, a cellular phone, a tablet computer, a webcam, a video camera, a video surveillance system, and a video gaming system.

17. A method for constructing an image sensor pixel, the method comprising: forming a plurality of photodetectors, the plurality of photodetectors including at least a first photodetector and a second photodetector; forming a first spectral router positioned above at least the first photodetector and the second photodetector, wherein the first spectral router is configured to: directing incident light in a first subset of a first color wavelength range to the first photodetector, and directing incident light in a second subset of the first color wavelength range to the second photodetector; as well as A second spectrum router is formed, the second spectrum router being positioned above the first spectrum router, wherein the second spectrum router is configured to: directing the incident light in the first subset and the second subset of the first color wavelength range to the first spectral router, and Incident light in the second color wavelength range is directed to one or more adjacent image sensor pixels.

18. The method of claim 17, wherein the plurality of photodetectors further comprises a third photodetector and a fourth photodetector, wherein the first spectral router is further positioned above the third photodetector and the fourth photodetector, and wherein the first photodetector, the second photodetector, the third photodetector, and the fourth photodetector are arranged in a two-by-two grid.

19. The method according to claim 18, wherein the first spectrum router is further configured to: directing incident light of a third subset of the first color wavelength range to the third photodetector, and Incident light of a fourth subset of the first color wavelength range is directed to the fourth photodetector.

20. The method according to claim 18, wherein the first spectrum router is further configured to: directing the incident light of the second subset of the first color wavelength range to the third photodetector, and The incident light of the first subset of the first color wavelength range is directed to the fourth photodetector.

Images