Image sensor comprising a color separator with two different refractive indices and different heights

Abstract

An image sensor is presented comprising pixels for acquiring color information from incident visible light, wherein the image sensor comprises three pixels covered by a color separator structure portion, the color separator structure being configured to deviate only one color channel of the incident visible light to one of the three pixels and to deviate other colors of the incident visible light to other pixels of the three pixels. The color separator structure comprises a first parallelepiped structure (101), a second parallelepiped structure (103) and a third parallelepiped structure (102), the structures being arranged such that the first and third parallelepiped structures are side by side and in contact with the second parallelepiped structure, and wherein the first and third parallelepiped structures have the same dimensions and are made of the same dielectric material having a refractive index n H , and wherein the height (H2) of the second parallelepiped structure is smaller than the height (H1) of the first and third parallelepiped structures, and wherein the second parallelepiped structure is made of a dielectric material having a refractive index n L , and wherein the refractive index n H is larger than the refractive index n L .

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of optics and photonics, and more specifically to optical devices used in image sensors. BACKGROUND

[0002] This section is intended to introduce the reader to various aspects of art that can be related to various aspects of the present application that are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present application. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0003] In order to capture color components during image acquisition, typically image sensors can use a Bayer filter (which is a way of discretizing the color space, which requires performing an interpolation later to generate a color image) or a foveated sensor (which is able to record three color components per pixel via a stack of color sensors, i.e. the color sensors are stacked on top of each other).

[0004] A specific technique based on a bi-material structure has been proposed in European patent application 18305265. However, no green deviation was observed with this method.

[0005] In order to provide an alternative to the known techniques, a specific structure / architecture for implementing a color separation function within an image sensor is proposed in the following, which can perform a deviation for red, green or blue colors. SUMMARY

[0006] Reference in the specification to "one embodiment", "an embodiment", "example embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment, but not necessarily all embodiments, of the application. The various appearances of "an embodiment" or "one embodiment" or "an

[0007] In one aspect, an image sensor is presented comprising a pixel for acquiring color information from incident visible light. The image sensor is remarkable in that it comprises three pixels covered by a color separator structure portion for deviating only one color channel of the incident visible light towards one of the three pixels and for deviating other colors of the incident visible light towards other ones of the three pixels, wherein the color separator structure comprises a first parallelepiped structure, a second parallelepiped structure and a third parallelepiped structure arranged such that the first and third parallelepiped structures are side by side and in contact with the second parallelepiped structure, and wherein the first and third parallelepiped structures have the same dimensions and are made of the same dielectric material having a refractive index n H , and wherein the second parallelepiped structure is smaller in height than the first and third parallelepiped structures, and wherein the second parallelepiped structure is made of a dielectric material having a refractive index n L , and wherein the refractive index n H is greater than the refractive index n L .

[0008] In a variant, the image sensor is remarkable in that the first, second and third parallelepiped structures have all their bottom angles equal to 90°.

[0009] In a variant, the image sensor is remarkable in that the height H1 of the first and third parallelepiped structures and the height H2 of the second parallelepiped structure demonstrate that the height H2 is smaller than the height H1, and wherein the first and third parallelepiped structures have the same width W1, while the second parallelepiped structure has a width W2.

[0010] In a variant, the image sensor is remarkable in that the color separator structure is comprised or embedded in a host medium having a refractive index n H equal to 2.2, the refractive index n L equal to 1.5, the refractive index n equal to 1, the width W1 equal to 600 nm, the width W2 equal to 200 nm, the height H1 equal to 500 nm, and the height H2 equal to 200 nm.

[0011] In a variant, the image sensor is remarkable in that the color separator structure is comprised or embedded in a host medium having a refractive index n, and the color separator structure deviates only the green component from the incident visible light towards one of the three pixels, wherein the refractive index n H equals 2.2, the refractive index n L equals 1.5, the refractive index n equals 1, the width W1 equals 600 nm, the width W2 equals 600 nm, the height H1 equals 600 nm, and the height H2 equals 250 nm.

[0012] In a variant, the image sensor is remarkable in that the color separator structure is comprised or embedded in a host medium having a refractive index n, and the color separator structure deviates only the red component from the incident visible light towards one of the three pixels, wherein the refractive index n H equals 1.8, the refractive index n L equals 1.6, the refractive index n equals 1, the width W1 equals 600 nm, the width W2 equals 600 nm, the height H1 equals 900 nm, and the height H2 equals 200 nm. 4. BRIEF DESCRIPTION OF DRAWINGS

[0013] The present disclosure can be better understood with reference to the following description and drawings, given by way of example and not limiting, and in which:

[0014] Fig. 1 (a) represents a side view of a color separator structure according to one embodiment of the application, Fig. 1 (b) represents a top view of a color separator structure according to one embodiment of the application;

[0015] Figure 2 and Figure 3(a) , 3(b) The orientation of some nanofountains produced by a color separator structure according to one embodiment of the present disclosure is shown;

[0016] Figure 4 Figs. 4 (a) and 4 (b) respectively show the power density distribution in the xz plane of a single material element and a double material element (the double material element corresponding to a color separator structure according to one embodiment of the present disclosure);

[0017] Figure 5 The power density distribution in a hot spot of a double material element (or color separator element) having the following parameters is shown: n = 1.0, n H = 2.2, H1 = 600 nm, H2 = 400 nm, W1 = 600 nm, W2 = 600 nm, W3 = 200 nm, W4 = 600 nm, W4 = 700 nm;

[0018] Figures 6(a), (b) and (c) show the power density distribution in a hot spot for a two-material element (or color splitter structure) with some specific parameters;

[0019] Figure 7 The power density distribution in a hot spot for a two-material element (or color splitter structure) with the following parameters is shown: n = 1.0, n H = 2.2, n L = 1.5, H1 = 600 nm, H2 = 400 nm, W1 = 600 nm, W2 = 600 nm, W4 = 600 nm, W5 = 700 nm;

[0020] Figure 8 The power density distribution in a hot spot for a two-material structure (or color splitter structure) with the following parameters is shown: n = 1.0, n H = 2.2, n L = 1.5, H1 = 600 nm, H2 = 400 nm, W1 = 600 nm, W2 = 600 nm, W3 = 100 nm, W4 = 600 nm;

[0021] Figure 9 The power density distribution for a two-material structure (or color splitter structure) with the following parameters is shown: n = 1.0, W1 = 600 nm, W4 = 600 nm, W5 = 700 nm;

[0022] Figure 10 A blue color splitter is shown, which splits the full spectrum of the incoming light into two channels: blue (B) in the center, the rest (W-B = G+R) pointing to the side, according to one embodiment of the present disclosure;

[0023] Figure 11 A green color splitter is shown, which splits the full spectrum of the incoming light (R+G+B) into two channels: green (G) in the center, the rest (W-G = B+R) pointing to the side;

[0024] Figure 12 A red color splitter is shown, which splits the full spectrum of the incoming light (R+G+B) into two channels: red (R) in the center, the rest (W-R = B+G) pointing to the side;

[0025] Figure 13 Different arrangements of color splitters according to the present disclosure are shown. The period of the two splitter elements is 2 pm, and the pixel pitch is 667 nm, which indicates that each splitter element (including the spacing between two adjacent splitters) feeds exactly three pixels;

[0026] Figure 14 A color splitter according to the present disclosure is provided, comprising: Figure 13description of the information recorded by the pixels of the image sensor of the embodiment of the disclosure mentioned in part a) of the disclosure;

[0027] Figure 15 A description of the information recorded by the pixels of the image sensor of the embodiment of the disclosure mentioned in part b) of the disclosure is provided; Figure 13

[0028] A description of the information recorded by the pixels of the image sensor of the embodiment of the disclosure mentioned in part c) of the disclosure is provided. Figure 16 Figure 13 DETAILED DESCRIPTION

[0029] The present invention relates to an improvement of the technology described in European patent application 18305265. More precisely, it is proposed to modify the technology of European patent application 18305265 so as to also deviate from green light.

[0030] Figure 1(a) shows a side view of a color separator structure according to one embodiment of the disclosure.

[0031] More precisely, figure 1(a) is a cross-sectional view of a color separator structure, wherein the color separator structure comprises two parallelepiped structures 101 and 102 made of the same dielectric material with a refractive index equal to n H . The two parallelepiped structures 101, 102 are sandwiched by a third structure labeled 103 made of a dielectric material with a refractive index equal to n L .

[0032] The parallelepiped structure 101 has a width W1 and a height H1.

[0033] The parallelepiped structure 102 has a width W1 and a height H1.

[0034] The parallelepiped structure 103 has a width W2 and a height H2, the height H2 being lower than the height H1.

[0035] In addition, the color separator structure is included or embedded in a host medium with a refractive index n lower than the refractive index n H .

[0036] The parallelepiped structures 101, 102 and 103 are also defined by the base angles a1, a2, a3, a4.

[0037] In figure 1(a), we have a1 = a2 = a3 = a4 = 90°.

[0038] ​​When the incident white light hits the color separator structure, then jet light waves are generated by the edges of the color separator structure, as already explained in documents WO 2017-162880 and WO 2017-162882.

[0039] Figure 1(b) shows a top view of a color separator structure, according to one embodiment of the disclosure.

[0040] More precisely, it shows the width W4 which is the value that can be considered as the thickness of the parallelepiped structures 101, 102 and 103. Moreover, the distances W3 and W5 correspond to the distance between a parallelepiped structure of a color separator to another color separator. Thus, the depth of a pixel is equal to W5+W4 and the width of a pixel is equal to (W3+2*W1+W2) / 3.

[0041] Figure 2 and Figure 3(a) 、 3(b) shows the orientation of the jet light waves generated by the color separator structure, according to one embodiment of the disclosure.

[0042] Indeed, when illuminated, the color separator structure generates nanometric jet light beams resulting from the interference of plane waves and jet waves (labeled 201, 202 and 203) generated by the edges of the blocks of the structure at an angle θ JW1 and θ JW2 diffraction, where:

[0043]

[0044]

[0045] The constructive interference between these jet waves and the plane waves leads to the generation of a new set of spectral-dependent NJ light beams.

[0046] Figure 3(a) and 3(b) shows the refraction of the jet waves associated with different edges due to the variation of the system parameters.

[0047] It can be demonstrated that by changing the size of the parallelepiped structures, we can make the nanometric jet (also noted NJ) light beams or hot spots to be located at different wavelengths above the surface of the structure along the element symmetry axis. This response of the color separator structure corresponds to the constructive interference between the plane waves and the jet waves propagating through the central parallelepiped structure of the color separator structure. To obtain the maximum intensity of this NJ, we should consider the phase of the jet wave generated by the parallelepiped structure with the highest refractive index and the plane wave generated outside this block to find the optimal parameters of the system. This means that for example the optical path difference (OPD) of JW1 and the plane wave refracted by the central block should satisfy the condition:

[0048] OPD ~ mλ,

[0049] where m = 0, ±1, ±2,...

[0050] We determine the OPD as:

[0051] OPD = n H AB + nBC - nCD - n L DE.

[0052] We obtain:

[0053]

[0054] where

[0055] To calculate the distance of the corresponding hot spot detection, we use the approximate formula:

[0056]

[0057] It must be mentioned that the properties of the system depend on the material and size of the blocks. We should also take into account the refraction of JW inside the element with refractive index n H Due to the refraction of JW2 inside the element, we can get an additional NJhot spot along the symmetry axis of the system. However, the phase of the jet wave produced by the opposite edges of the element will be different. This means that the optical path difference (OPD) for a plane wave propagating through the central block and JW2 should satisfy the condition:

[0058]

[0059] where m = 0, ±1, ±2,...

[0060] It should also be noted that the color separation properties of the proposed structure are not limited to structures with a vertical base angle (a j = 90°). In fact, the expected goal can still be achieved with a base angle of 80° to 110°.

[0061] Moreover, the color separation function is not limited to normal incidence light (θ = 0°), but it also exists for oblique incidence light.

[0062] In fact, normal incidence occurs at θ = 0°, but the color separation structure can perform a separation function with a tolerance range of -15° < θ < 15°.

[0063] Figure 4 Figures 4(a) and 4(b) show single- Figure 4 Figures 4(a) and 4(b) show single- Figure 4b) the power density distribution of the material element in the xz plane to illustrate the input from the parallelepiped structure 102 with refractive indices n L = 2.2 at Z = 800 nm (we assume that Z = 0 corresponds to the bottom of the system).

[0064] More precisely, Figure 4 The parameters of the structure of (a) and 4(b) are as follows:

[0065] n = 1.0, W1 = 600 nm, W2 = 600 nm, W3 = 200 nm, W4 = 600 nm, W5 = 700 nm;

[0066] (a) n H = n L = 2.2, H 1,2 = 600 nm;

[0067] (b) n H = 2.2, n L = 1.5, H1 = 600 nm, H2 = 250 nm.

[0068] At X = 1000 nm (the middle of the system, Figure 4 b), we can observe a strong response of the system at the wavelengths corresponding to green color. Red and blue will be almost suppressed. A full analysis of the JW distribution and the interference shows that at this distance from the top of the element, the main input will be provided by NJ, which is the result of constructive interference between JW1 and the plane wave refracted by the central block. The schematic distribution of JW in this system is provided below.

[0069] Figure 5 The power density distribution in the hot spot of a two-material element with the following parameters is shown: n = 1.0, n H = 2.2, H1 = 600 nm, H2 = 400 nm, W1 = 600 nm, W2 = 600 nm, W3 = 200 nm, W4 = 600 nm, W5 = 700 nm. For Figure 5 , 6(a) , 6(b), 6(c), 7 and 8, the legends of the solid, dashed and dotted lines are the same as in Figure 4 .

[0070] Figures 6(a), (b) and (c) show the power density distribution in the hot spot of a two-material element with the following parameters:

[0071] n = 1.0, n H = 2.2, n L= 1.5, H1 = 600 nm, H2 = 400 nm, W1 = 600 nm, W2 = 600 nm, W3 = 100 nm, W4 = 600 nm.

[0072] Figure 7 The power density distribution in a hot spot for a two-material element with the following parameters is shown: n = 1.0, n H = 2.2, n L = 1.5, H1 = 600 nm, H2 = 400 nm, W1 = 600 nm, W2 = 600 nm, W4 = 600 nm, W5 = 700 nm.

[0073] Figure 8 The power density distribution in a hot spot for a two-material element with the following parameters is shown: n = 1.0, n H = 2.2, n L = 1.5, H1 = 600 nm, H2 = 400 nm, W1 = 600 nm, W2 = 600 nm, W3 = 100 nm, W4 = 600 nm.

[0074] Due to the optimization of the system parameters, we have obtained solutions for three different color splitters. Figure 9 A comparison of the power density distribution for single and two-material elements is shown in Fig. 5. Note that the total size of the elements is the same, which is necessary.

[0075] Figure 9 The power density distribution for a two-material element with the following parameters is shown: n = 1.0, W1 = 600 nm, W4 = 600 nm, W5 = 700 nm;

[0076] (a) n H = 2.2, n L = 1.5, H1 = 500 nm, H2 = 200 nm, W2 = 200 nm, W3 = 600 nm, Z = 800 nm;

[0077] (b) n H = 2.2, n L = 1.5, H1 = 600 nm, H2 = 250 nm, W2 = 600 nm, W3 = 200 nm, Z = 800 nm;

[0078] (c) n H = 1.8, n L = 1.6, H1 = 900 nm, H2 = 200 nm, W2 = 600 nm, W3 = 200 nm, Z = 1500 nm.

[0079] Figure 10 A blue splitter is shown, which separates the full spectrum of incident light into two channels: blue (B) in the center, the rest (W-B = G+R) directed to the sides. The total width of the splitter element is 1400 nm, and together with the spacing between adjacent elements (in this case 600 nm), the pitch period of the splitter elements becomes 2 pm. In this embodiment, the refractive index n Figure 10 , 11 and 12, the legends of the drawn solid, dashed and dotted lines are the same as in Figure 9 .

[0080] The total width of the splitter element is 1400 nm, and together with the spacing between adjacent elements (in this case 600 nm), the pitch period of the splitter elements becomes 2 pm. In this embodiment, the refractive index n H equals 2.2, the refractive index n L equals 1.5, the refractive index n equals 1, the width W1 equals 600 nm, the width W2 equals 200 nm, the height H1 equals 500 nm, and the height H2 equals 200 nm.

[0081] Figure 11 A green splitter is shown, which separates the full spectrum of incident light (R+G+B) into two channels: green (G) in the center, the rest (W-G = B+R) directed to the sides.

[0082] The total width of the splitter element is 1800 nm, and together with the spacing between adjacent elements (in this case 200 nm), the pitch period of the splitter elements becomes 2 pm.

[0083] In this embodiment, the refractive index n H equals 2.2, the refractive index n L equals 1.5, the refractive index n equals 1, the width W1 equals 600 nm, the width W2 equals 600 nm, the height H1 equals 600 nm, and the height H2 equals 250 nm.

[0084] Figure 12 A red splitter is shown, which separates the full spectrum of incident light (R+G+B) into two channels: red (R) in the center, the rest (W-R = B+G) directed to the sides. The total width of the splitter element is 1800 nm, and together with the spacing between adjacent elements (in this case 200 nm), the pitch period of the splitter elements becomes 2 pm.

[0085] In this embodiment, the refractive index n H equals 1.8, the refractive index n L equals 1.6, the refractive index n equals 1, the width W1 equals 600 nm, the width W2 equals 600 nm, the height H1 equals 900 nm, and the height H2 equals 200 nm.

[0086] Figure 13 A different arrangement of color separators according to this disclosure is shown. The period of the two separator elements is 2 μm and the pixel pitch is 667 nm, which indicates that each separator element (including the spacing between two adjacent separators) precisely feeds three pixels.

[0087] In one embodiment, the color separator is used in conjunction with some or all of the pixels that use conventional color filters. In this embodiment, conventional color filters are used to filter out residual wavelengths of unwanted wavelengths in the separated portion of the incident light. Therefore, crosstalk is minimized, while the color separator increases the efficiency of light entry.

[0088] In another embodiment, the image sensor has non-uniform pixel sizes. The pixel sizes are optimized based on the array of color separator elements to achieve better color separation performance, light capture, etc.

[0089] Figure 14 Provided according to Figure 13 The description of the information recorded by the pixels of the image sensor in the embodiments of the present disclosure mentioned in part a).

[0090] Figure 15 Provided according to Figure 13 Description of the information recorded by the pixels of the image sensor in the embodiments of the present disclosure mentioned in part b).

[0091] Figure 16 Provided according to Figure 13 The description of the information recorded by the pixels of the image sensor in the embodiments of the present disclosure mentioned in part c)

Claims

1. An image sensor for acquiring color information from incident visible light, the image sensor comprising: a first set of three pixels partially covered by a first color separator structural element, the first color separator structural element for deviating only a blue color channel of the incident visible light to one of the first set of three pixels, and for deviating other colors of the incident visible light to other pixels of the first set of three pixels, wherein the first color separator structural element partially covers each of the first set of three pixels, a second set of three pixels partially covered by a second color separator structural element, the second color separator structural element for deviating only a green color channel of the incident visible light to one of the second set of three pixels, and for deviating other colors of the incident visible light to other pixels of the second set of three pixels, wherein the second color separator structural element partially covers each of the second set of three pixels, and a third set of three pixels partially covered by a third color separator structural element, the third color separator structural element for deviating only a red color channel of the incident visible light to one of the third set of three pixels, and for deviating other colors of the incident visible light to other pixels of the third set of three pixels, wherein the third color separator structural element partially covers each of the third set of three pixels, wherein each of the first color separator structure element, the second color separator structure element, the third color separator structure element comprises a first parallelepiped structure, a second parallelepiped structure and a third parallelepiped structure, the first, second and third parallelepiped structures being arranged such that the first and third parallelepiped structures are side by side in a direction perpendicular to a height direction and in contact with the second parallelepiped structure in a direction perpendicular to the height direction, and wherein the first and third parallelepiped structures have the same dimensions and are made of the same dielectric material having a refractive index n H n1, and wherein the second parallelepiped structure is smaller in height than the first and third parallelepiped structures, and wherein the second parallelepiped structure is made of a dielectric material having a refractive index n L n2, wherein the refractive index n H n2 is larger than the refractive index n L n1.

2. The image sensor of claim 1, wherein the first, second, and third parallelepiped structures have all bottom angles equal to 90°.

3. The image sensor of any of claims 1-2, wherein the first parallelepiped structure and the third parallelepiped structure have a height H 1 and the second parallelepiped structure has a height H 2, the height H 2 being less than the height H 1, and wherein, The first and third parallelepiped structures have the same width W 1, and the second parallelepiped structure has a width W 2.

4. The image sensor according to claim 3, wherein the first color separator structure element is comprised or embedded in a matrix medium having a refractive index n , wherein the refractive index n H equals 2.2, the refractive index n L equals 1.5, the refractive index n equals 1, the width W 1 equals 600 nm, the width W 2 equals 200 nm, the height H 1 equals 500 nm, and the height H 2 equals 200 nm.

5. The image sensor of claim 3, wherein the two-color separator structure elements are comprised of or embedded in a matrix medium having refractive indices n , wherein the refractive index n H equals 2.2, the refractive index n L equals 1.5, the refractive index n equals 1, the width W 1 equals 600 nm, the width W 2 equals 600 nm, the height H 1 equals 600 nm, and the height H 2 equals 250 nm.

6. The image sensor of claim 3, wherein the three-color separator structure elements are comprised of or embedded in a matrix medium having refractive indices n , wherein the refractive index n H equals 1.8, the refractive index n L equals 1.6, the refractive index n equals 1, the width W 1 equals 600 nm, the width W 2 equals 600 nm, the height H 1 equals 900 nm, and the height H 2 equals 200 nm.

7. An image sensing method for acquiring color information from incident visible light using an image sensor, the image sensor comprising: a first set of three pixels partially covered by a first color separator structural element, the first color separator structural element for deviating only a blue color channel of the incident visible light to one of the first set of three pixels, and for deviating other colors of the incident visible light to other pixels of the first set of three pixels, wherein the first color separator structural element partially covers each of the first set of three pixels, a second set of three pixels partially covered by a second color separator structural element, the second color separator structural element for deviating only a green color channel of the incident visible light to one of the second set of three pixels, and for deviating other colors of the incident visible light to other pixels of the second set of three pixels, wherein the second color separator structural element partially covers each of the second set of three pixels, and a third set of three pixels partially covered by a third color separator structural element, the third color separator structural element for deviating only a red color channel of the incident visible light to one of the third set of three pixels, and for deviating other colors of the incident visible light to other pixels of the third set of three pixels, wherein the third color separator structural element partially covers each of the third set of three pixels, 8. The image sensing method of claim 7, wherein the first, second, and third parallelepiped structures have all bottom angles equal to 90°. wherein each of the first color separator structure element, the second color separator structure element, the third color separator structure element comprises a first parallelepiped structure, a second parallelepiped structure and a third parallelepiped structure, the first, second and third parallelepiped structures being arranged such that the first and third parallelepiped structures are side by side in a direction perpendicular to a height direction and in contact with the second parallelepiped structure in the direction perpendicular to the height direction, and wherein the first and third parallelepiped structures have the same dimensions and are made of the same dielectric material having a refractive index n H n1, and wherein the second parallelepiped structure is smaller in height than the first and third parallelepiped structures, and wherein the second parallelepiped structure is made of a dielectric material having a refractive index n L n2, wherein the refractive index n H n2 is larger than the refractive index n L n1.

8. The image sensing method of claim 7, wherein the first, second and third parallelepiped structures have all bottom angles equal to 90°.

9. The image sensing method of any of claims 7-8, wherein the first parallelepiped structure and the third parallelepiped structure have a height H 1 and the second parallelepiped structure has a height H 2, the height H 2 being less than the height H 1, and wherein, The first and third parallelepiped structures have the same width W 1, and the second parallelepiped structure has a width W 2.

10. The image sensing method of claim 9, wherein the first color separator structure element is comprised of or embedded in a matrix medium having a refractive index n , wherein the refractive index n H equals 2.2, the refractive index n L equals 1.5, the refractive index n equals 1, the width W 1 equals 600 nm, the width W 2 equals 200 nm, the height H 1 equals 500 nm, and the height H 2 equals 200 nm.

11. The image sensing method of claim 9, wherein the second color separator structure element is comprised of or embedded in a matrix medium having refractive indices n , wherein the refractive index n H equals 2.2, the refractive index n L equals 1.5, the refractive index n equals 1, the width W 1 equals 600 nm, the width W 2 equals 600 nm, the height H 1 equals 600 nm, and the height H 2 equals 250 nm.

12. The image sensing method of claim 9, wherein the third color separator structure element is comprised of or embedded in a matrix medium having refractive indices n , wherein the refractive index n H equals 1.8, the refractive index n L equals 1.6, the refractive index n equals 1, the width W 1 equals 600 nm, the width W 2 equals 600 nm, the height H 1 equals 900 nm, and the height H 2 equals 200 nm.

13. A color separator, comprising: a first color separator element configured for deviating only a blue color channel of incident visible light to one of three first pixels of an image sensor and for deviating other colors of the incident visible light to other ones of the three first pixels, wherein the first color separator element partially covers each of the three first pixels, a second color separator element configured for deviating only a green color channel of the incident visible light to one of three second pixels of an image sensor and for deviating other colors of the incident visible light to other ones of the three second pixels, wherein the second color separator element partially covers each of the three second pixels, and a third color separator element configured for deviating only a red color channel of the incident visible light to one of three third pixels of an image sensor and for deviating other colors of the incident visible light to other ones of the three third pixels, wherein the third color separator element partially covers each of the three third pixels, wherein each of the first, second and third color separator elements comprises: a first, a second and a third parallelepiped structure arranged such that the first and third parallelepiped structures are arranged on opposite sides of the second parallelepiped structure in a direction perpendicular to a height direction of the color separator and in contact with the second parallelepiped structure in the direction perpendicular to the height direction; wherein the first and third parallelepiped structures have the same dimensions and are made of the same dielectric material, and wherein the second parallelepiped structure is smaller in height than the first and third parallelepiped structures, wherein said first parallelepiped structure and said third parallelepiped structure have a refractive index n H , said second parallelepiped structure has a refractive index n L , and n H greater than said refractive index n L .

14. The color separator of claim 13, wherein n H between 1.8 and 2.2, and n L between 1.5 and 1.

6.

15. The color separator of claim 13, wherein the first parallelepiped structure and the third parallelepiped structure have a width W 1 that is greater than a width W 1 of the second parallelepiped structure W 2.

16. The color separator of claim 15, wherein W 2 between 200 nm and 600 nm.

17. The color separator of claim 13, wherein the first parallelepiped structure and the third parallelepiped structure have a height between 500 nm and 900 nm H 1, and the second parallelepiped structure has a height between 200 nm and 250 nm H 2.

Images