Stacked type image sensor including color separation element and image pickup apparatus including stacked type image sensor

A stacked type image sensor including color separation elements, and an image pickup apparatus including the stacked type image sensor, are provided. The stacked type image sensor includes a first light sensing layer including first pixels configured to absorb and detect light of a first wavelength band and transmit light of a second wavelength band and a third wavelength band, and a second light sensing layer disposed to face the first light sensing layer, the second light sensing layer including second pixels configured to detect light of the second wavelength band and third pixels configured to detect light of the third wavelength band. The color separation elements are disposed between the first light sensing layer and the second light sensing layer, and are configured to direct the light of the second wavelength band toward the second pixels, and direct the light of the third wavelength band toward the third pixels.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No. 10-2014-0143605, filed on Oct. 22, 2014, in the Korean Intellectual Property Office, the disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

Apparatuses and methods consistent with exemplary embodiments relate to a stacked type image sensor including a color separation element and an image pickup apparatus including the stacked type image sensor.

2. Description of the Related Art

Color displays and color image sensors may display multicolor images and detect colors of light incident thereon by using color filters. Color displays and color image sensors may use an RGB color filter scheme in which, for example, green filters are disposed in two of four pixels and blue and red filters are disposed in the other two pixels. Alternatively, a CYGM color filter scheme, in which filters of complementary colors, i.e., cyan, yellow, green, and magenta, are respectively disposed in four pixels, may be used.

However, since the color filters absorb all colors of light except for a filtered color, the light use efficiency of the color filters may be low. For example, since RGB color filters may transmit only about ⅓ of incident light and absorb about ⅔ of the incident light, the light use efficiency of the RGB color filters may only be about 33%. Therefore, most of the optical loss of the color filters of the color displays or the color image sensors may be caused by the color filters.

Attempts have been made to use color separation elements rather than the color filters to increase light use efficiency of the color displays and the color image sensors. The color separation elements may separate colors of incident light based on diffraction or refraction characteristics of light varying according to wavelengths of light, and may transmit the separated colors to pixels of corresponding colors. Therefore, the light use efficiency may be higher when using the color separation elements than the color filters. However, since color separation efficiency of color separation elements may change according to incident angles of light, color separation efficiency of a plurality of pixels of an image sensor may vary, and thus, the plurality of pixels may have different sensitivities.

SUMMARY

According to an aspect of an exemplary embodiment, there is provided an image sensor including a first light sensing layer including first pixels configured to absorb and detect light of a first wavelength band and transmit light of a second wavelength band and a third wavelength band, and a second light sensing layer disposed to face the first light sensing layer, the second light sensing layer including second pixels configured to detect light of the second wavelength band and third pixels configured to detect light of the third wavelength band. The image sensor further includes color separation elements disposed between the first light sensing layer and the second light sensing layer, the color separation elements being configured to direct the light of the second wavelength band toward the second pixels, and direct the light of the third wavelength band toward the third pixels, and each of the color separation elements being symmetric in at least four directions parallel to a surface of the second light sensing layer.

The first pixels may be arranged in a two-dimensional (2D) array structure, and the second pixels and the third pixels may be alternately arranged in a 2D array structure.

The first pixels, the second pixels and the third pixels may be a same size, and boundaries of the first pixels may be aligned with boundaries of the second pixels and the third pixels.

Each of the first pixels may overlap a portion of one of the second pixels and a portion of one of the third pixels.

The second light sensing layer may include first pixel rows in which the second pixels and the third pixels are alternately arranged in an order of a second pixel and a third pixel in a first direction, and second pixel rows in which the third pixels and the second pixels are alternately arranged in an order of a third pixel and a second pixel in the first direction. The first pixel rows and the second pixel rows may be alternately arranged in a second direction perpendicular to the first direction.

The color separation elements may be disposed to face the respective second pixels, and the color separation elements may be configured to direct the light of the second wavelength band in a straight downward direction, and direct the light of the third wavelength band toward sides of the color separation elements.

Each of the color separation elements may be symmetric in a horizontal direction of the second light sensing layer, a vertical direction of the second light sensing layer, a first diagonal direction, and a second diagonal direction that intersects the first diagonal direction.

Each of the color separation elements may include a first arm that extends in a first diagonal direction and a second arm that extends in a second diagonal direction that intersects the first diagonal direction.

The color separation elements may be disposed to face the respective third pixels, and the color separation elements may be configured to direct the light of the third wavelength band in a straight downward direction, and direct the light of the second wavelength band toward sides of the color separation elements.

Each of the color separation elements may be shaped as at least one of a square tube, a cylinder, a cylindrical tube, a hexagonal pillar, and a hexagonal tube.

The color separation elements may be disposed to face respective interfaces between the second pixels and the third pixels, and the color separation elements may be configured to direct the light of the second wavelength band toward first sides of the color separation elements, and direct the light of the third wavelength band toward second sides of the color separation elements, the second sides being opposite to the first sides.

The image sensor may further include a color filter layer including a first color filter that is disposed on the second pixels and is configured to transmit the light of the second wavelength band to the second pixels, and a second color filter that is disposed on the third pixels and is configured to transmit the light of the third wavelength band to the third pixels.

The image sensor may further include a transparent dielectric layer disposed between the first and second light sensing layers, the transparent dielectric layer covering the color separation elements.

The color separation elements may include a material having a refractive index greater than that of the transparent dielectric layer.

According to an aspect of another exemplary embodiment, there is provided an image pickup apparatus including an image sensor, the image sensor including a first light sensing layer including first pixels configured to absorb and detect light of a first wavelength band and transmit light of a second wavelength band and a third wavelength band, and a second light sensing layer disposed to face the first light sensing layer, the second light sensing layer including second pixels configured to detect light of the second wavelength band and third pixels configured to detect light of the third wavelength band. The image sensor further includes color separation elements disposed between the first light sensing layer and the second light sensing layer, the color separation elements being configured to direct the light of the second wavelength band toward the second pixels, and direct the light of the third wavelength band toward the third pixels.

Each of the color separation elements may be symmetric in at least four directions parallel to a surface of the second light sensing layer.

DETAILED DESCRIPTION

Hereinafter, a stacked type image sensor including color separation elements and an image pickup apparatus including the image sensor will be described in detail with reference to the accompanying drawings. In the drawings, like reference numbers refer to like elements, and also the size of each element may be exaggerated for clarity of illustration. Exemplary embodiments described herein are for illustrative purposes only, and various modifications may be made therefrom. In the following description, when an element is referred to as being “above” or “on” another element in a layered structure, it may be directly on the other element while making contact with the other element or may be above the other element without making contact with the other element. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

FIG. 1is a schematic cross-sectional view of a structure of an image sensor according to an exemplary embodiment. Referring toFIG. 1, the image sensor100includes a first light sensing layer140including a plurality of first pixels Px1absorbing and detecting light of a first wavelength band and transmitting light of other wavelength bands. The image sensor100further includes a second light sensing layer110including a plurality of second pixels Px2detecting light of a second wavelength band and a plurality of third pixels Px3detecting light of a third wavelength band. The image sensor100further includes color separation elements130disposed between the first light sensing layer140and the second light sensing layer110. The color separation elements130direct light of the second wavelength band passed through the first light sensing layer140toward the second pixels Px2of the second light sensing layer110, and direct light of the third wavelength band passed through the first light sensing layer140toward the third pixels Px3of the second light sensing layer110.

In addition, the image sensor100further includes a transparent dielectric layer120disposed between the first light sensing layer140and the second light sensing layer110. The image sensor100further includes a first transparent electrode141and a second transparent electrode142respectively disposed on a lower surface and an upper surface of the first light sensing layer140. The image sensor100further includes a plurality of microlenses150disposed on top of the second transparent electrode142. The color separation elements130are covered by and fixed in the transparent dielectric layer120. The first transparent electrode141and the second transparent electrode142apply driving voltages to the first light sensing layer140, and may be formed of, for example, a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), or gallium zinc oxide (GZO).

The first light sensing layer140and the second light sensing layer110are stacked as shown inFIG. 1. In detail, the transparent dielectric layer120is disposed on an upper surface of the second light sensing layer110, and the first light sensing layer140is disposed on an upper surface of the transparent dielectric layer120opposite the second light sensing layer110. In this case, the first light sensing layer140and the second light sensing layer110are configured to detect light of different wavelength bands. In detail, the first light sensing layer140absorbs only light of a first wavelength band, and transmits light of second and third wavelength bands. For example, the first light sensing layer140may absorb only light of a green wavelength band, and may transmit light of red and blue wavelength bands.

FIG. 2Ais a graph of a transmission spectrum of the first light sensing layer140of the image sensor100ofFIG. 1. Referring to the graph inFIG. 2A, the first light sensing layer140transmits most blue light in a 400-nm wavelength band and most red light in a 700-nm wavelength band, but absorbs most green light in a 530-nm wavelength band. The first light sensing layer140having the above-described characteristics may include a material such as, for example, rhodamine-based pigment, a merocyanine-based pigment, or quinacridone.

According to the exemplary embodiment, however, the absorbed wavelength band of the first light sensing layer140is not limited to a green wavelength band. Alternatively, the first light sensing layer140may only absorb and detect light of a red wavelength band, and may transmit light of blue and green wavelength bands. Alternatively, the first light sensing layer140may only absorb light of a blue wavelength band, and may transmit light of green and red wavelength bands. For example, the first light sensing layer140may include a phthalocyanine-based pigment to detect light of a green wavelength band, or may include a material such as a coumarin-based pigment, tris-(8-hydroxyquinoline) aluminum (Alq3), or a merocyanine-based pigment to detect light of a blue wavelength band. For convenience of description, the following description will be presented under the assumption that the first light sensing layer140only absorbs and detects light of a green wavelength band, and transmits light of red and blue wavelength bands.

As described above, since light of a first wavelength band incident on the image sensor100is absorbed by the first light sensing layer140, only light of second and third wavelength bands is transmitted through the first light sensing layer140. After passing through the first light sensing layer140, the light of the second and third wavelength bands are incident on the transparent dielectric layer120, and then are separated by the color separation elements130. The color separation elements130are disposed at a light entrance side of the second light sensing layer110to separate the incident light according to the wavelengths thereof so that the different wavelengths of the incident light enter different pixels. The color separation elements130separate colors of the incident light thereon by changing a propagation direction of the incident light according to the wavelengths of the incident light based on diffraction or refraction characteristics of the light varying according to the wavelengths of the light. Accordingly, the color separation elements130may be formed of a material having a refractive index greater than that of the transparent dielectric layer120that surrounds the color separation elements130. For example, the transparent dielectric layer120may be formed of SiO2or siloxane-based spin-on-glass (SOG), and the color separation elements130may be formed of a material having a high refractive index such as TiO2, SiN3, ZnS, ZnSe, or Si3N4. Various structures are known in the related art as structures for color separation elements. Thus, the structure of the color separation elements130may be variously designed according to desired spectrum distributions of exiting light.

Referring again toFIG. 1, the color separation elements130divide incident light thereon into light C2of a second wavelength band and light C3of a third wavelength band. In this example, the color separation elements130does not change a propagation direction of the light C2of the second wavelength band, and changes a propagation direction of the light C3of the third wavelength band toward lateral sides thereof. Then, the light C2of the second wavelength band is incident on the second pixels Px2located under the color separation elements130, and the light C3of the third wavelength band is incident on the third pixels Px3located at the lateral sides of the color separation elements130. Therefore, the second pixels Px2located under the color separation elements130detect the light C2of the second wavelength band, and the third pixels Px3located at the lateral sides of the color separation elements130detect the light C3of the third wavelength band. For example, the light C2of the second wavelength band may be blue light, and the light C3of the third wavelength band may be red light.

FIG. 2Bis a graph of a color separation spectrum of the color separation elements130of the image sensor100ofFIG. 1. As shown inFIG. 2B, the color separation elements130separate light of a blue wavelength band and light of a red wavelength band by directing the light of the blue wavelength band in a straight downward direction toward a center pixel of the second light sensing layer110and directing the light of the red wavelength band toward left and right sides thereof toward left and right pixels of the center pixel. In this way, the first light sensing layer140absorbs and detects green light, and the second light sensing layer110detects the blue and red light transmitted through the first light sensing layer140.

Referring again toFIG. 1, according to the exemplary embodiment, the first pixels Px1of the first light sensing layer140and the second and third pixels Px2and Px3may have the same size.

FIG. 3is a schematic plan view of a pixel structure of the first light sensing layer140of the image sensor100ofFIG. 1, andFIG. 4is a schematic plan view of a pixel structure of the second light sensing layer110of the image sensor of100FIG. 1. Referring toFIGS. 3 and 4, the first pixels Px1of the first light sensing layer140are arranged in a two-dimensional (2D) array structure, and the second and third pixels Px2and Px3of the second light sensing layer110are arranged in a 2D array structure. The first pixels Px1of the first light sensing layer140may match the second and third pixels Px2and Px3of the second light sensing layer110in such a manner that boundaries of the first pixels Px1are aligned with those of the second and third pixels Px2and Px3.

Referring toFIG. 4, the second and third pixels Px2and Px3of the second light sensing layer110are alternately arranged in rows and columns. For example, the second light sensing layer110includes first pixel rows P1in which the plurality of second pixels Px2and the plurality of third pixels Px3are alternately arranged in an order of the second pixels Px2before the third pixels Px3in a left-to-right horizontal direction, and second pixel rows P2in which the plurality of third pixels Px3and the plurality of second pixels Px2are alternately arranged in an order of the third pixels Px3before the second pixels Px2in the left-to-right horizontal direction. The first pixel rows P1and the second pixel rows P2are alternately arranged in a vertical direction. The color separation elements130are disposed to face the second pixels Px2. Therefore, the color separation elements130provide light C2of a second wavelength band for the second pixels Px2, and light C3of a third wavelength band for the third pixels Px3disposed at left and right sides of the second pixels Px2.

As shown inFIG. 4, each of the color separation elements130includes a first arm130aextending in a first diagonal direction, and a second arm130bextending in a second diagonal direction that intersects the first diagonal direction. The color separation elements130are symmetric in at least four directions parallel to a surface of the second light sensing layer110, when viewing from a normal direction of the second light sensing layer110. For example, the color separation elements130shown inFIG. 4are symmetric in a horizontal axis (x-axis) direction of the second light sensing layer110, a vertical direction (y-axis) of the second light sensing layer110, the first diagonal direction, and the second diagonal direction. Since the color separation elements130are symmetric in at least four directions, that is, have a structure with at least four-fold symmetry, an extent to which color separation efficiency of the color separation elements130changes based on the center of the image sensor100in an azimuth direction, may be decreased.

FIG. 5is a schematic diagram of the second light sensing layer110, illustrating a principle related to the color separation elements130shown inFIG. 4having substantially constant color separation efficiency with respect to directions of incident light. Referring toFIG. 5, it is assumed that an azimuth φ of a right peripheral area (i) in the second light sensing layer110is 0°, and an azimuth φ of an upper peripheral area (iii) in the second light sensing layer110is 90°. Since the color separation elements130have a structure with at least four-fold symmetry, characteristics of the color separation elements130may be almost identical in areas where an azimuth φ is 0°, 90°, 180°, and 270°. That is, the color separation efficiency of the color separation elements130may almost be the same in the right peripheral area (i) and the upper peripheral area (iii). However, in a diagonal peripheral area (ii) in the second sensing layer110, the color separation efficiency of the color separation elements130may be different from that in the right peripheral area (i) and the upper peripheral area (iii).

If the color separation elements130are only symmetric with respect to any axis, the color separation efficiency of the color separation elements130disposed in an area where an azimuth φ is 0° may be greatly different from the color separation efficiency of the color separation elements130disposed in an area where an azimuth φ is 180°. Also, if the color separation elements130are symmetric with respect to only two axes, the color separation efficiency of the color separation elements130disposed in an area where an azimuth φ is 0° may be greatly different from the color separation efficiency of the color separation elements130disposed in an area where an azimuth φ is 90°. According to the exemplary embodiment, since the color separation elements130have a structure with at least four-fold symmetry, the color separation efficiency of the color separation elements130disposed in left and right peripheral areas of the image sensor100may be almost the same as the color separation efficiency of the color separation elements130disposed in upper and lower peripheral areas of the image sensor100. Therefore, sensitivities of a plurality pixels of the image sensor100may be relatively constant.

According to the exemplary embodiment, since the first light sensing layer140and the second light sensing layer110of the image sensor100are arranged in a stacked manner, a number of pixels per area may be increased. Therefore, a resolution of the image sensor100may be improved. Also, the first light sensing layer140may absorb and detect most of light of a first wavelength band. In addition, light of second and third wavelength bands separated by the color separation elements130may be detected by the second light sensing layer110almost without any loss. Therefore, light may be efficiently used. Thus, a sensitivity of the image sensor100may be improved. Furthermore, the color separation elements130may be configured to separate only light of two wavelength bands, and thus, the color separation elements130may be easily designed and manufactured. The image sensor100may be applied to various image pickup apparatuses for providing high-quality images.

FIG. 6is a graph of color separation efficiency of the pixel structure of the second light sensing layer110ofFIG. 4. In the graph ofFIG. 6, ‘R filter’ refers to transmission characteristics of a red filter, ‘G filter’ refers to transmission characteristics of a green filter, and ‘B filter’ refers to transmission characteristics of a blue filter. Also, in the graph ofFIG. 6, ‘R’ refers to an absorption spectrum in the second pixels Px2, and ‘B1’ refers to an absorption spectrum in the third pixels Px3. As shown inFIG. 6, a larger amount of light may be absorbed when the second pixels Px2and the third pixels Px3are used than when color filters are used.

The above-described structures of the first light sensing layer140and the second light sensing layer110of the image sensor100and the above-described characteristics of the color separation elements130are exemplary embodiments of structures and characteristics. That is, image sensors having various structures other than those described above may be provided. For example, various color separation characteristics may be obtained according to a design of the color separation elements130, and the structure of the second light sensing layer110may be variously modified according to the design of the color separation elements130. Furthermore, a relative arrangement of the first light sensing layer140and the second light sensing layer110may be variously modified.

FIG. 7is a schematic cross-sectional view of a structure of an image sensor200according to another exemplary embodiment. In comparison to the image sensor100shown inFIG. 1, the first light sensing layer140and the second light sensing layer110of the image sensor200shown inFIG. 7are shifted relative to each other. For example, the first light sensing layer140may be shifted relative to the second light sensing layer110by ½ of a pixel width. Therefore, first pixels Px1of the first light sensing layer140may range over halves of second and third pixels Px2and Px3of the second light sensing layer110. Therefore, each of the first pixels Px1of the first light sensing layer140may overlap a portion of one of the second pixels Px2and a portion of one of the third pixels Px3. Thus, a resolution of the image sensor200may be improved by analyzing color information of the overlapping portions.

FIG. 8is a schematic cross-sectional view of a structure of an image sensor300according to another exemplary embodiment. Referring toFIG. 8, the image sensor300includes the first light sensing layer140including a plurality of first pixels Px1absorbing and detecting light of a first wavelength band and transmitting light of other wavelength bands. The image sensor300further includes the second light sensing layer110including a plurality of second pixels Px2detecting light of a second wavelength band, and a plurality of third pixels Px3detecting light of a third wavelength band. The image sensor300further includes color separation elements131disposed between the first light sensing layer140and the second light sensing layer110.

The color separation elements131direct light of the second wavelength band passed through the first light sensing layer140toward the second pixels Px2of the second light sensing layer110, and light of the third wavelength band passed through the first light sensing layer140toward the third pixels Px3of the second light sensing layer110. In comparison to the exemplary embodiment shown inFIG. 1, the color separation elements131face the third pixels Px3instead of the second pixels Px2. Therefore, the color separation elements131changes a propagation direction of light C2of the second wavelength band to be inclined toward lateral sides without changing a propagation direction of light C3of the third wavelength band. Accordingly, the light C3of the third wavelength band is incident on the third pixels Px3that are directly below the color separation elements131, and the light C2of the second wavelength band is incident on the second pixels Px2at the lateral sides of the color separation elements131.

FIG. 9is a schematic plan view of a pixel structure of the second light sensing layer110of the image sensor300ofFIG. 8. Referring toFIG. 9, the second and third pixels Px2and Px3of the second light sensing layer110are alternately arranged in rows and columns. For example, the second light sensing layer110includes first pixel rows P1in which the plurality of second and third pixels Px2and Px3are alternately arranged in an order of a third pixel Px3before a second pixel Px2in a left-to-right horizontal direction, and second pixel rows P2in which the plurality of second and third pixels Px2and Px3are alternately arranged in an order of a second pixel Px2before a third pixel Px3in the left-to-right horizontal direction. The first pixel rows P1and the second pixel rows P2are alternately arranged in a vertical direction. The color separation elements131are disposed to face the third pixels Px3.

As shown inFIG. 9, each of the color separation elements131are shaped as, for example, a square tube. Therefore, the color separation elements131are symmetric in at least four directions parallel to a surface of the second light sensing layer110, when viewing from a normal direction of the second light sensing layer110. For example, the color separation elements131are symmetric in a horizontal axis (x-axis) direction of the second light sensing layer110, a vertical direction (y-axis) of the second light sensing layer110, a first diagonal direction, and a second diagonal direction. As described above, since the color separation elements131are symmetric in at least four directions, that is, have a structure with at least four-fold symmetry, an extent to which color separation efficiency of the color separation elements131changes based on the center of the image sensor100in an azimuth direction, may be decreased.

FIG. 10is a graph of color separation efficiency of the pixel structure of the second light sensing layer110ofFIG. 9. In the graph ofFIG. 10, ‘R filter’ refers to transmission characteristics of a red filter, ‘G filter’ refers to transmission characteristics of a green filter, and ‘B filter’ refers to transmission characteristics of a blue filter. Also, in the graph ofFIG. 10, ‘R’ refers to an absorption spectrum in the second pixels Px2, and ‘B′’ refers to an absorption spectrum in the third pixels Px3. As shown inFIG. 10, a larger amount of light may be absorbed when the second pixels Px2and the third pixels Px3are used than when color filters are used.

The color separation elements130ofFIG. 4, which are color separation elements having a structure with four-fold symmetry, are illustrated as including the first and second arms130aand130bthat perpendicularly cross each other in two diagonal directions. Also, each of the color separation elements131ofFIG. 9is illustrated as being shaped as a square tube. However, other than the structures of the color separation elements130and131ofFIGS. 4 and 9, respectively, color separation elements may have various structures with more than four-fold symmetry according to desired color separation characteristics. For example, color separation elements having a shape of a cylinder, a cylindrical tube, a hexagonal pillar, a hexagonal tube, or other various forms may be selected and used according to properties of image sensors.

FIG. 11is a schematic cross-sectional view of a structure of an image sensor400according to another exemplary embodiment. The image sensor400shown inFIG. 11includes color separation elements132configured to direct light C2of a second wavelength band toward left sides and light C3of a third wavelength band toward right sides. In this case, the color separation elements132are arranged to face interfaces between second and third pixels Px2and Px3. Therefore, the light C2of the second wavelength band separated by the color separation elements132are incident on the second pixels Px2disposed at the left sides of the color separation elements132, and the light C3of the third wavelength band separated by the color separation elements132are incident on the third pixels Px3disposed at the right sides of the color separation elements132. The color separation elements132ofFIG. 11may also be configured to have a structure with at least four-fold symmetry. Other elements of the image sensor400ofFIG. 11may be the same as those of the image sensor100ofFIG. 1.

Other color separation elements having various color separation characteristics may be used, and pixel arrangements of the first light sensing layer140and the second light sensing layer110may vary according to the color separation characteristics of the color separation elements.

A distance between the color separation elements130,131, or132and the second light sensing layer110may be several micrometers or shorter, for example,1micrometer or shorter. Since the distance between the color separation elements130,131, or132and the second light sensing layer110is short, colors may not be fully separated in some cases. Thus, color filters may additionally be used to reduce a possibility of color mixing and improve color reproducibility.

FIGS. 12 to 14are schematic cross-sectional views of structures of image sensors100a,300a,and400a,respectively, according to other exemplary embodiments. Referring toFIG. 12, the image sensor100afurther includes a color filter layer160as compared with the image sensor100illustrated inFIG. 1. Referring toFIG. 13, the image sensor300afurther includes a color filter layer160as compared with the image sensor300illustrated inFIG. 8. Referring toFIG. 14, the image sensor400afurther includes a color filter layer160as compared with the image sensor400illustrated inFIG. 11. In each case, the color filter layer160is disposed on top of the second light sensing layer110. For example, the color filter layer160includes second color filters CF2disposed on top of second pixels Px2and transmitting only light C2of a second wavelength band, and third color filters CF3disposed on top of third pixels Px3and transmitting only light C3of a third wavelength band. Although the color filter layer160is used, since the light C2and the light C3significantly separated by color separation elements130,131, or132are incident on the color filters CF2and CF3, respectively, an optical loss caused by the color filter layer160may not be large. Therefore, the image sensors100a,300a,and400aillustrated inFIGS. 12 to 14may have high light use efficiency and excellent color reproducibility.

As described above, according to the above exemplary embodiments, a stacked type image sensor including color separation elements and an image pickup apparatus including the image sensor have been described with reference to the accompanying drawings. However, it should be understood that the exemplary embodiments described herein are to be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each exemplary embodiment should be considered as available for other similar features or aspects in other exemplary embodiments.