Patent Description:
Image sensors using spectral filters are one of important optical instruments in the field of optics. Image sensors according to the related art, including various optical devices, are bulky and heavy. Recently, according to the demand for miniaturization of image sensors, research has been conducted to simultaneously implement an integrated circuit and an optical element on a single semiconductor chip. <CIT> discloses an optical sensing device with a mult-cavity Fabry-Perot light filter.

One or more example embodiments provide a spectral filter, and an image sensor and an electronic device, each including the spectral filter.

Additional aspects will be set forth in part in the description, which follows and, in part, will be apparent from the description, or may be learned by practice of example embodiments.

According to an aspect of an example embodiment, there is provided a spectral filter including a first unit filter having a first center wavelength in a first wavelength range, and a second unit filter having a second center wavelength in a second wavelength range, wherein the first unit filter includes two first metal reflective layers provided spaced apart from each other and including a first metal, and a first cavity provided between the two first metal reflective layers, and wherein the second unit filter includes two second metal reflective layers provided spaced apart from each other and including a second metal different from the first metal, and a second cavity provided between the two second metal reflective layers.

The first unit filter and the second unit filter may be provided in one dimension or two dimensions on a plane.

The first center wavelength in the first wavelength range may be shorter than the second center wavelength in the second wavelength range.

The two first metal reflective layers may include one of aluminum (Al), silver (Ag), gold (Au), or titanium nitride (TiN), and the two second metal reflective layers may include one of copper (Cu), Ag, Au, or TiN that is different from the two first reflective metal layers.

The first unit filter may be included in a first filter array including a plurality of first unit filters having different center wavelengths, and the second unit filter may be included in a second filter array including a plurality of second unit filters having different center wavelengths.

The center wavelength of the first unit filter may be configured to be adjusted based on changing a thickness or an effective refractive index of the first cavity, and the center wavelength of the second unit filter may be configured to be adjusted based on changing a thickness or an effective refractive index of the second cavity.

The first unit filter may further include a first dielectric layer that is provided above the first cavity and a second dielectric layer provided below the first cavity, and the second unit filter may further include a third dielectric layer provided below the second cavity and a fourth dielectric layer provided above the second cavity.

Each of the first dielectric layer, a second dielectric layer, a third dielectric layer, and a fourth dielectric layer may include a single layer or multiple layers.

Each of the first dielectric layer, the second dielectric layer, the third dielectric layer, and the fourth dielectric layer may have a thickness ranging from <NUM> to <NUM>.

At least one of a thickness or an effective refractive index of each of the first dielectric layer and the second dielectric layer may be adjusted based on the center wavelength of the first unit filter, and a thickness or an effective refractive index of each of the third dielectric layer and the fourth dielectric layer may be adjusted based on the center wavelength of the second unit filter.

The spectral filter may further include a plurality of microlenses provided on the first unit filter and the second unit filter.

The spectral filter may further include a color filter provided on a same plane as the first unit filter and the second unit filter.

The spectral filter may further include an additional filter provided on the first unit filter and the second unit filter, the additional filter being configured to transmit a preset wavelength band.

The additional filter may include a color filter or a broadband filter.

The first unit filter may include a plurality of first unit filters and the second unit filter includes a plurality of second unit filters, and a short wavelength absorption filter may be provided in some of the plurality of first unit filters and the plurality of second unit filters, and a long wavelength cut-off filter may be provided in other of the plurality of first unit filters and the plurality of second unit filters.

According to another aspect of an example embodiment, there is provided a spectral filter including at least one first unit filter having a first center wavelength in a first wavelength range, and at least one second unit filter having a second center wavelength in a second wavelength range, wherein the at least one first unit filter includes a plurality of metal reflective layers provided spaced apart from each other, and at least one first cavity provided between the plurality of metal reflective layers, and wherein the at least one second unit filter includes a plurality of Bragg reflective layers provided spaced apart from each other, and at least one second cavity provided between the plurality of Bragg reflective layers.

The at least one first unit filter and the at least one second unit filter may be provided in one dimension or two dimensions on a plane.

The first center wavelength of the at least one first unit filter may be configured to be adjusted based on changing a thickness or an effective refractive index of the at least one first cavity, and the second center wavelength of the at least one second unit filter may be configured to be adjusted based on changing a thickness or n effective refractive index of the at least one second cavity.

The spectral filter may further include a plurality of microlenses provided on the at least one first unit filter and the at least one second unit filter.

The spectral filter may further include a color filter provided on the plane.

The spectral filter may further include an additional filter provided on the at least one first unit filter and the at least one second unit filter, the additional filter being configured to transmit a preset wavelength band.

According to another aspect of an example embodiment, there is provided an image sensor including a spectral filter, and a pixel array configured to receive light transmitted through the spectral filter, wherein the spectral filter includes at least one first unit filter having a first center wavelength in a first wavelength range, and at least one second unit filter having a second center wavelength in a second wavelength range, wherein the at least one first unit filter includes a plurality of first metal reflective layers provided spaced apart from each other and including a first metal, and at least one first cavity provided between the plurality of first metal reflective layers, and wherein the at least one second unit filter includes a plurality of second metal reflective layers provided spaced apart from each other and including a second metal different from the first metal, and at least one second cavity provided between the plurality of second metal reflective layers.

The at least one first unit filter may further include a first dielectric layer provided below the at least one first cavity and a second dielectric layer provided above the at least one first cavity, and the at least one second unit filter may further include a third dielectric layer provided below the at least one second cavity and a fourth dielectric layer provided above the at least one second cavity.

The spectral filter may further include a color filter, and the at least one first unit filter, the at least one second unit filter, and the color filter may be provided on a same plane.

The image sensor may further include a timing controller, a row decoder, and an output circuit.

An electronic device including the image sensor.

The electronic device may be one of a mobile phone, a smartphone, a tablet, a smart tablet, a digital camera, a camcorder, a notebook computer, a television, a smart television, a smart refrigerator, a security camera, a robot, or a medical camera.

According to another aspect of an example embodiment, there is provided an image sensor including a spectral filter, and a pixel array configured to receive light transmitted through the spectral filter, wherein the spectral filter includes at least one first unit filter having a first center wavelength in a first wavelength range, and at least one second unit filter having a second center wavelength in a second wavelength range, wherein the at least one first unit filter includes a plurality of metal reflective layers provided spaced apart from each other, and at least one first cavity provided between the plurality of metal reflective layers, and wherein the at least one second unit filter includes a plurality of Bragg reflective layers provided spaced apart from each other, and at least one second cavity provided between the plurality of Bragg reflective layers.

The spectral filter may further include a color filter, and the at least one first unit filter, the at least one second unit filter, and the color filter are provided on a same plane.

An electronic device may include the image sensor.

According to another aspect of an example embodiment, there is provided a spectral filter including a first unit filter having a first center wavelength in a first wavelength range, and a second unit filter having a second center wavelength in a second wavelength range, the second unit filter being provided adjacent to the first unit filter in a horizontal direction, wherein the first unit filter includes two first metal reflective layers provided spaced apart from each other in a vertical direction and including a first metal, and a first cavity provided between the two first metal reflective layers, and wherein the second unit filter includes two second metal reflective layers provided spaced apart from each other in the vertical direction and including a second metal different from the first metal, and a second cavity provided between the two second metal reflective layers.

The size of each constituent element illustrated in the drawings may be exaggerated for convenience of explanation and clarity. In the above, although embodiments have been described, these are merely exemplary, and those skilled in the art to which the present disclosure pertains could make various modifications and changes from these descriptions.

When a constituent element is disposed "above" or "on" to another constituent element, the constituent element may include not only an element directly contacting on the upper/lower/left/right sides of the other constituent element, but also an element disposed above/under/left/right the other constituent element in a noncontact manner. It will be further understood that the terms "comprises" and/or "comprising" used herein specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the disclosure are to be construed to cover both the singular and the plural. Also, the steps of all methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The disclosure is not limited to the described order of the steps.

Furthermore, terms such as "to portion," "to unit," "to module," and "to block" stated in the specification may signify a unit to process at least one function or operation and the unit may be embodied by hardware, software, or a combination of hardware and software.

Furthermore, the connecting lines, or connectors shown in the various figures presented are intended to represent functional relationships and/or physical or logical couplings between the various elements.

The use of any and all examples, or language (e.g., "such as") provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed.

<FIG> is a schematic block diagram of an image sensor <NUM> according to an example embodiment.

Referring to <FIG>, the image sensor <NUM> may include a spectral filter <NUM>, a pixel array <NUM>, a timing controller <NUM>, a row decoder <NUM>, and an output circuit <NUM>. The image sensor <NUM> may include a charge coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor, but embodiments are not limited thereto.

The spectral filter <NUM> may include a plurality of unit filters that transmit light of different wavelength ranges and are arranged in two dimensions. The pixel array <NUM> may include a plurality of pixels that detect light of different wavelengths that are transmitted through the unit filters. For example, the pixel array <NUM> may include pixels arranged in two dimensions along a plurality of rows and columns. The row decoder <NUM> may select one of the rows of the pixel array <NUM> in response to a row address signal output from the timing controller <NUM>. The output circuit <NUM> may output a light detection signal in units of columns from the pixels arranged in a selected row. To this end, the output circuit <NUM> may include a column decoder and an analog to digital converter (ADC). For example, the output circuit <NUM> may include a plurality of ADCs arranged for each column between the column decoder and the pixel array <NUM>, or a single ADC arranged at an output end of the column decoder. The timing controller <NUM>, the row decoder <NUM>, and the output circuit <NUM> may be implemented by a single chip or separate chips. A processor for processing an image signal output through the output circuit <NUM> may be implemented by a single chip with the timing controller <NUM>, the row decoder <NUM>, and the output circuit <NUM>. The pixel array <NUM> may include a plurality of pixels that detect light of different wavelengths, and the pixels may be arranged in various methods.

In the following description, the spectral filter <NUM> of the image sensor <NUM> is described in detail. <FIG> is a schematic cross-sectional view of a spectral filter taken along line II-II' of <FIG>.

Referring to <FIG> and <FIG>, the spectral filter <NUM> may include a plurality of unit filters arranged in one dimension or two dimensions. <FIG> illustrates an example of cross-sections of six unit filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

The spectral filter <NUM> may include a first filter array <NUM> and a second filter array <NUM> arranged on a plane. Although the first and second filter arrays <NUM> and <NUM> may be arranged on substantially the same plane, embodiments are not limited thereto. The first filter array <NUM> may include at least one unit filter having a center wavelength in a first wavelength range. The first wavelength range may be a range of, for example, about <NUM> to about <NUM>. However, this is merely exemplary, and the first wavelength range may also be various wavelength ranges according to a design condition. <FIG> illustrates an example in which the first filter array <NUM> includes a first unit filter <NUM>, a second unit filter <NUM>, and a third unit filter <NUM>.

The second filter array <NUM> may include at least one unit filter having a center wavelength in a second wavelength range. The second wavelength range may be greater than the first wavelength range. For example, the second wavelength range may be a range of about <NUM> to about <NUM>. However, this is merely exemplary, and the second wavelength range may also be various wavelength ranges according to a design condition. <FIG> illustrates a case in which the second filter array <NUM> includes a fourth unit filter <NUM>, a fifth unit filter <NUM>, and a sixth unit filter <NUM>.

<FIG> illustrates a case in which each of the first and second filter arrays <NUM> and <NUM> includes three unit filters <NUM>, <NUM>, and <NUM>, and <NUM>, <NUM>, and <NUM>, however embodiments are not limited thereto, and the number of unit filters constituting each of the first and second filter arrays <NUM> and <NUM> may be variously changed.

Each of the first, second, and third unit filters <NUM>, <NUM>, and <NUM> constituting the first filter array <NUM> may transmit light having a specific center wavelength in the first wavelength range, and have a Fabry-Perot structure in which cavities <NUM>, <NUM>, and <NUM> are provided adjacent to each other in a horizontal direction and between two first metal reflective layers <NUM> and <NUM> spaced apart from each other in a vertical direction.

When light is incident on the cavities <NUM>, <NUM>, and <NUM> by transmitting through the first metal reflective layers <NUM> and <NUM>, the light may reciprocate between the first metal reflective layers <NUM> and <NUM> inside the cavities <NUM>, <NUM>, and <NUM>, during which a constructive interference and a destructive interference occur. Light having a specific center wavelength and satisfying a constructive interference condition may exit to the outside of each of the first, second, and third unit filters <NUM>, <NUM>, and <NUM>. The wavelength band and the center wavelength of the light passing through the first, second, and third unit filters <NUM>, <NUM>, and <NUM> may be determined according to a reflection band of the first metal reflective layers <NUM> and <NUM> and the characteristics, for example, a thickness and a refractive index, of each of the cavities <NUM>, <NUM>, and <NUM>.

The first metal reflective layers <NUM> and <NUM> may include a first metal capable of reflecting light in the first wavelength range. For example, the first metal may include aluminum (Al), silver (Ag), gold (Au), titanium nitride (TiN), and the like. However, embodiments are not limited thereto. The first metal reflective layers <NUM> and <NUM> may have a thickness of, for example, tens of nanometers, however embodiments are not limited thereto. For example, the first metal reflective layers <NUM> and <NUM> may have a thickness of about <NUM> to about <NUM>.

The cavities <NUM>, <NUM>, and <NUM> provided between the first metal reflective layers <NUM> and <NUM>, as resonance layers, may include a dielectric material having a certain refractive index. For example, an average refractive index of the cavity with a single transmission peak may range from <NUM> to <NUM>, and the thickness may range from around <NUM> to <NUM>. For example, when the center wavelength may range from around <NUM> to <NUM>, the cavity thickness may range around <NUM> to <NUM> with the refractive index being between <NUM> and <NUM>. When the center wavelength ranges from around <NUM> to <NUM>, the cavity thickness may range from around <NUM> to <NUM> with the refractive index being between <NUM> and <NUM>. In a multi-mode cavity, a thickness of the cavity may be increased.

For example, the cavities <NUM>, <NUM>, and <NUM> may include silicon, a silicon oxide, a silicon nitride, a hafnium oxide, or a titanium oxide, or a combination of these materials. For example, the cavities <NUM>, <NUM>, and <NUM> may include a TiO<NUM>/SiN multilayer or patterned structures of TiO<NUM>/SiO<NUM>. However, embodiments are not limited thereto.

The first, second, and third unit filters <NUM>, <NUM>, and <NUM> may have different center wavelengths in the first wavelength range. To this end, the first, second, and third unit filters <NUM>, <NUM>, and <NUM> may respectively include the first, second, and third cavities <NUM>, <NUM>, and <NUM> having different thicknesses. <FIG> illustrates an example in which the second cavity <NUM> is thicker than the first cavity <NUM>, and the third cavity <NUM> is thicker than the second cavity <NUM>. In this case, among the first, second, and third unit filters <NUM>, <NUM>, and <NUM>, the third unit filter <NUM> may have the longest center wavelength, and the first unit filter <NUM> may have the shortest center wavelength. Furthermore, some unit filters may have a plurality of center wavelengths corresponding to the thickness of a cavity.

Each of the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> constituting the second filter array <NUM> may transmit light having a specific center wavelength in the second wavelength range, and may have a Fabry-Perot structure in which cavities <NUM>, <NUM>, and <NUM> are provided between two second metal reflective layers <NUM> and <NUM> spaced apart from each other. The wavelength band and the center wavelength of the light passing through the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> may be determined according to a reflection band of the second metal reflective layers <NUM> and <NUM> and the characteristics of the cavities <NUM>, <NUM>, and <NUM>.

The second metal reflective layers <NUM> and <NUM> may include a second metal capable of reflecting light in the second wavelength range. For example, the second metal may include copper (Cu), Ag, Au, TiN, and the like. However, embodiments are not limited thereto. The second metal reflective layer may have a thickness of, for example, tens of nanometers, but embodiments are not limited thereto. For example, the second metal reflective layers <NUM> and <NUM> may have a thickness of about <NUM> to about <NUM>.

The second metal constituting the second metal reflective layers <NUM> and <NUM> may be a metal different from the first metal constituting the above-described first metal reflective layers <NUM> and <NUM>. For example, when the first metal reflective layers <NUM> and <NUM> include Al, the second metal reflective layers <NUM> and <NUM> may include Cu. Furthermore, for example, when the first metal reflective layers <NUM> and <NUM> include Al, the second metal reflective layers <NUM> and <NUM> may include Ag. Furthermore, for example, when the first metal reflective layers <NUM> and <NUM> include Ag, the second metal reflective layers <NUM> and <NUM> may include Cu.

The cavities <NUM>, <NUM>, and <NUM> provided between the second metal reflective layers <NUM> and <NUM>, as resonance layers, may include a dielectric material having a certain refractive index. For example, the cavities <NUM>, <NUM>, and <NUM> may include silicon, a silicon oxide, a silicon nitride, a hafnium oxide, or a titanium oxide.

The cavities <NUM>, <NUM>, and <NUM> provided between the second metal reflective layers <NUM> and <NUM> may include the same material as the cavities <NUM>, <NUM>, and <NUM> provided between the first metal reflective layers <NUM> and <NUM>. In this case, the thicknesses of the cavities <NUM>, <NUM>, and <NUM> provided between the second metal reflective layers <NUM> and <NUM> may be different from the thicknesses of the cavities <NUM>, <NUM>, and <NUM> provided between the first metal reflective layers <NUM> and <NUM>. The cavities <NUM>, <NUM>, and <NUM> provided between the second metal reflective layers <NUM> and <NUM> may include a material different from the cavities <NUM>, <NUM>, and <NUM> provided between the first metal reflective layers <NUM> and <NUM>. The thickness of the cavities may vary depending on the material of the metal reflective layers provided on the cavities. A thickness of the cavity may correspond to a thickness of a skin depth of the material of the metal reflective layers. For example, a thickness of a cavity provided between Al metal reflectors may be greater than a cavity provided between Cu metal reflectors for a unit filter having a same center wavelength.

The fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> may have different center wavelengths in the second wavelength range. To this end, the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> may include the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> having different thicknesses. <FIG> illustrates a case in which the fifth cavity <NUM> is thicker than the fourth cavity <NUM>, and the sixth cavity <NUM> is thicker than the fifth cavity <NUM>. In this case, among the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM>, the sixth unit filter <NUM> may have the longest center wavelength, and the fourth unit filter <NUM> may have the shortest center wavelength. Furthermore, some unit filters may have a plurality of center wavelengths according to the thickness of a cavity.

As described above, as the first filter array <NUM> in which the cavities <NUM>, <NUM>, and <NUM> are provided between the first metal reflective layers <NUM> and <NUM> and the second filter array <NUM> in which the cavities <NUM>, <NUM>, and <NUM> are provided between the second metal reflective layers <NUM> and <NUM> are arranged on a plane, a spectral filter having the characteristics of a broadband including the first wavelength range and the second wavelength range, for example, a wavelength range from ultraviolet to near infrared, may be implemented.

<FIG> is a cross-sectional view of a unit filter <NUM> having a TiO<NUM> cavity between Cu reflective layers. <FIG> is a cross-sectional view of a unit filter <NUM> having a TiO<NUM> dielectric layer in each of upper and lower portions of a structure of <FIG>.

<FIG> is a graph of transmittance spectrums of the unit filter <NUM> of <FIG> and the unit filter <NUM> of <FIG>. In <FIG>, "A" denotes a transmittance spectrum of the unit filter <NUM> of <FIG>, and "B" denotes a transmittance spectrum of the unit filter <NUM> of <FIG>. Referring to <FIG>, it may be seen that the unit filter <NUM> of <FIG> has a higher transmittance than the unit filter <NUM> of <FIG>.

As such, the unit filter <NUM> with an improved transmittance may be implemented by further providing the TiO<NUM> dielectric layer in each of the upper and lower portions of the structure having the TiO<NUM> cavity between the Cu reflective layers. The thickness of the TiO<NUM> dielectric layer may be adjusted according to the center wavelength of the unit filter <NUM>.

<FIG> is a schematic cross-sectional view of a spectral filter <NUM> according to another example embodiment.

Referring to <FIG>, a first filter array <NUM> may include a first unit filter <NUM>, a second unit filter <NUM>, and a third unit filter <NUM> having center wavelengths in the first wavelength range. A second filter array <NUM> may include fourth unit filter <NUM>, a fifth unit filter <NUM>, and a sixth unit filter <NUM> having center wavelengths in the second wavelength range.

Each of the first, second, and third unit filters <NUM>, <NUM>, and <NUM> constituting the first filter array <NUM> may include the two first metal reflective layers <NUM> and <NUM> arranged spaced apart from each other, the cavities <NUM>, <NUM>, and <NUM> provided between the first metal reflective layers <NUM> and <NUM>, and first dielectric layer <NUM> and a second dielectric layer <NUM> respectively provided below and above each of the cavities <NUM>, <NUM>, and <NUM>. The first, second, and third unit filters <NUM>, <NUM>, and <NUM> may include the first, second, and third cavities <NUM>, <NUM>, and <NUM> having different thicknesses, to have different center wavelengths in the first wavelength range. The first metal reflective layers <NUM> and <NUM> and the first, second, and third cavities <NUM>, <NUM>, and <NUM> are similar to those described above with respect to <FIG>.

The first dielectric layer <NUM> may be provided below the first metal layer <NUM>, and the second dielectric layer <NUM> may be provided above the first metal layer <NUM>. The first and second dielectric layers <NUM> and <NUM> may improve transmittance of the first, second, and third unit filters <NUM>, <NUM>, and <NUM>. The first and second dielectric layers <NUM> and <NUM> may have a single layer structure. Each of the first and second dielectric layers <NUM> and <NUM> may include, for example, a titanium oxide, a silicon nitride, a hafnium oxide, a silicon oxide, a high index polymer, and the like. However, embodiments are not limited thereto.

The thicknesses of the first and second dielectric layers <NUM> and <NUM> may be changed according to the center wavelengths of the first, second, and third unit filters <NUM>, <NUM>, and <NUM>. <FIG> illustrates a case in which the thicknesses of the first and second dielectric layers <NUM> and <NUM> increase as the center wavelengths of the first, second, and third unit filters <NUM>, <NUM>, and <NUM> increase. Although the thickness of each of the first and second dielectric layers <NUM> and <NUM> may be about <NUM> to about <NUM>, embodiments are not limited thereto. For example, the thickness of each of the first and second dielectric layers <NUM> and <NUM> may range from about <NUM> to <NUM>.

Each of the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> constituting the second filter array <NUM> may include the two second metal reflective layers <NUM> and <NUM> arranged spaced apart from each other, the cavities <NUM>, <NUM>, and <NUM> provided between the second metal reflective layers <NUM> and <NUM>, and third dielectric layer <NUM> and a fourth dielectric layer <NUM> respectively provided below and above each of the cavities <NUM>, <NUM>, and <NUM>. The fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> may include the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> having different thicknesses, to have different center wavelengths in the second wavelength range. The second metal reflective layers <NUM> and <NUM> and the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> are as described above.

The third dielectric layer <NUM> may be provided below the second metal layer <NUM>, and the fourth dielectric layer <NUM> may be provided above the second metal layer <NUM>. The third and fourth dielectric layers <NUM> and <NUM> may be to improve transmittance of the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM>. The third and fourth dielectric layers <NUM> and <NUM> may have a single layer structure. Each of the third and fourth dielectric layers <NUM> and <NUM> may include, for example, a titanium oxide, a silicon nitride, a hafnium oxide, a silicon oxide, a high index polymer, and the like, like the above-described first and second dielectric layers <NUM> and <NUM>, but embodiments are not limited thereto.

The thicknesses of the third and fourth dielectric layers <NUM> and <NUM> may be changed according to the center wavelengths of the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM>. <FIG> illustrates a case in which the thicknesses of the third and fourth dielectric layers <NUM> and <NUM> increase as the center wavelengths of the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> increase. Although the thickness of each of the third and fourth dielectric layers <NUM> and <NUM> may be about <NUM> to about <NUM>, embodiments are not limited thereto. For example, the thickness of each of the third and fourth dielectric layers <NUM> and <NUM> may range from about <NUM> to <NUM>.

<FIG> is a graph of a transmittance spectrum of the spectral filter <NUM> of <FIG>. The first metal reflective layers <NUM> and <NUM> include Al, and the second metal reflective layers <NUM> and <NUM> include Cu, and the first to sixth cavities <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> include TiO<NUM>. The first, second, third, and fourth dielectric layers <NUM>, <NUM>, <NUM>, and <NUM> all include TiO<NUM>. In <FIG>, "C1" denotes a transmittance spectrum of the first filter array <NUM>, and "C2" denotes a transmittance spectrum of the second filter array <NUM>.

Referring to <FIG>, a first filter array <NUM> may include at least one unit filter having a center wavelength in a first wavelength range. A second filter array <NUM> may include at least one unit filter having a center wavelength in a second wavelength range.

<FIG> illustrates a case in which, for convenience of explanation, the first filter array <NUM> includes one unit filter (a first unit filter <NUM>), and the second filter array <NUM> includes one unit filter (a second unit filter <NUM>). When each of the first and second filter arrays <NUM> and <NUM> includes a plurality of unit filters, the unit filters may include cavities of different thicknesses.

The first unit filter <NUM> constituting the first filter array <NUM> may include the two first metal reflective layers <NUM> and <NUM> arranged spaced apart from each other, a first cavity <NUM> provided between the first metal reflective layers <NUM> and <NUM>, and first and second dielectric layers <NUM> and <NUM> respectively provided below and above the first cavity <NUM>.

The first dielectric layer <NUM> may be provided below the first metal layer <NUM>, and the second dielectric layer <NUM> may be provided above the first metal layer <NUM>. Each of the first and second dielectric layers <NUM> and <NUM> may include a titanium oxide, a silicon nitride, a hafnium oxide, a silicon oxide, a high index polymer, and the like, but embodiments are not limited thereto.

The first dielectric layer <NUM> may have a single layer structure. However, embodiments are not limited thereto, and the first dielectric layer <NUM> may have a multi-layer structure. The second dielectric layer <NUM> may have a multi-layer structure. For example, the second dielectric layer <NUM> may have a structure in which the first and second material layers 372a and 372b different from each other are alternately stacked. The thickness and number of material layers constituting the second dielectric layer <NUM> may be adjusted according to the center wavelength of the first unit filter <NUM>. The second dielectric layer <NUM> may include three or more material layers different from each other.

The second unit filter <NUM> constituting the second filter array <NUM> may include the second metal reflective layers <NUM> and <NUM> arranged spaced apart from each other, a second cavity <NUM> provided between the second metal reflective layers <NUM> and <NUM>, and third and fourth dielectric layers <NUM> and <NUM> respectively provided below and above the second cavity <NUM>.

The third dielectric layer <NUM> may be provided below the second metal layer <NUM>, and the fourth dielectric layer <NUM> may be provided above the second metal layer <NUM>. The third and fourth dielectric layers <NUM> and <NUM> may include a titanium oxide, a silicon nitride, a hafnium oxide, a silicon oxide, a high index polymer, and the like, like the first and second dielectric layers <NUM> and <NUM>, but embodiments are not limited thereto.

The third dielectric layer <NUM> may have a single layer structure or a multi-layer structure. The fourth dielectric layer <NUM> may have a multi-layer structure. For example, the fourth dielectric layer <NUM> may have a structure in which first and second material layers 382a and 382b different from each other are alternately stacked. The thickness and number of material layers constituting the fourth dielectric layer <NUM> may be adjusted according to the center wavelength of the second unit filter <NUM>. The fourth dielectric layer <NUM> may include three or more material layers different from one another.

<FIG> is a graph of a transmittance spectrum of the spectral filter <NUM> of <FIG>. <FIG> illustrates a transmittance spectrum in a case in which, in the spectral filter <NUM> of <FIG>, the first filter array <NUM> includes seven unit filters having different center wavelengths, and the second filter array <NUM> includes nine unit filters having different center wavelengths.

The first metal reflective layers <NUM> and <NUM> include Al, and the second metal reflective layers <NUM> and <NUM> include Cu, and each of the first and second cavities <NUM> and <NUM> include a multi-layer film of TiO<NUM> and SiN. Each of the first and third dielectric layers <NUM> and <NUM> include SiN, and each of the second and fourth dielectric layers <NUM> and <NUM> may include a multi-layer film of TiO<NUM> and SiN. In <FIG>, "D1" denotes a transmittance spectrum of the first filter array <NUM>, and "D2" denotes a transmittance spectrum of the second filter array <NUM>. Referring to <FIG>, it may be seen that the spectral filter <NUM> implements broadband characteristics and high transmittance.

<FIG> is a schematic cross-sectional view of a spectral filter <NUM> according to another example embodiment. <FIG> illustrates an example in which, for convenience of explanation, a first filter array <NUM> includes one unit filter (a first unit filter <NUM>), and a second filter array <NUM> includes one unit filter (a second unit filter <NUM>).

The first unit filter <NUM> constituting the first filter array <NUM> may include three first metal reflective layers <NUM>, <NUM>, and <NUM> arranged spaced apart from one another, and two first cavities <NUM> and <NUM> provided between the first metal reflective layers <NUM>, <NUM>, and <NUM>.

Each of the first metal reflective layers <NUM>, <NUM>, and <NUM> may include a first metal capable of reflecting light in a first wavelength range. Each of the first cavities <NUM> and <NUM> may include, for example, a dielectric material such as silicon, a silicon oxide, a silicon nitride, a hafnium oxide, a titanium oxide, and the like.

The second unit filter <NUM> constituting the second filter array <NUM> may include three second metal reflective layers <NUM>, <NUM>, and <NUM> arranged spaced apart from one another, and two second cavities <NUM> and <NUM> provided between the second metal reflective layers <NUM>, <NUM>, and <NUM>.

Each of the second metal reflective layers <NUM>, <NUM>, and <NUM> may include a second metal capable of reflecting light in a second wavelength range. Each of the second cavities <NUM> and <NUM> may include, for example, a dielectric material such as silicon, a silicon oxide, a silicon nitride, a hafnium oxide, a titanium oxide, and the like.

Although each of the first and second unit filters <NUM> and <NUM> is as described above as including two cavities (<NUM> and <NUM>, and <NUM> and <NUM>), each of the first and second unit filters <NUM> and <NUM> may include three or more cavities. Furthermore, although both of the first and second unit filters <NUM> and <NUM> are as described above as including a multi-cavity structure, one of the first and second unit filters <NUM> and <NUM> may have a single cavity structure and the other may have a multi-cavity structure.

Referring to <FIG>, the first unit filter <NUM> constituting the first filter array <NUM> may include the first metal reflective layers <NUM>, <NUM>, and <NUM> arranged spaced apart from one another, the first cavities <NUM> and <NUM> provided between the first metal reflective layers <NUM>, <NUM>, and <NUM>, and first and second dielectric layers <NUM> and <NUM> respectively provided below and above the first cavities <NUM> and <NUM>. The first metal reflective layers <NUM>, <NUM>, and <NUM> and the first cavities <NUM> and <NUM> are as described above.

The first dielectric layer <NUM> may be provided below the first metal reflective layer <NUM>, and the second dielectric layer <NUM> may be provided above the first metal reflective layer <NUM>. The first and second dielectric layers <NUM> and <NUM> are to improve transmittance, and may have a single layer or a multi-layer structure. Although each of the first and second dielectric layers <NUM> and <NUM> may include, for example, a titanium oxide, a silicon nitride, a hafnium oxide, a silicon oxide, a high index polymer, and the like, embodiments are not limited thereto.

The second unit filter <NUM> constituting the second filter array <NUM> may include the second metal reflective layers <NUM>, <NUM>, and <NUM> arranged spaced apart from one another, the second cavities <NUM> and <NUM> provided between the second metal reflective layers <NUM>, <NUM>, and <NUM>, and third and fourth dielectric layers <NUM> and <NUM> respectively provided below and above the second cavities <NUM> and <NUM>. The second metal reflective layers <NUM>, <NUM>, and <NUM> and the second cavities <NUM> and <NUM> are as described above.

The third dielectric layer <NUM> may be provided below the second metal reflective layer <NUM>, and the fourth dielectric layer <NUM> may be provided above the second metal reflective layer <NUM>. Although each of the third and fourth dielectric layers <NUM> and <NUM> may have a single layer or a multi-layer structure, and include, for example, a titanium oxide, a silicon nitride, a hafnium oxide, a silicon oxide, a high index polymer, and the like, embodiments are not limited thereto.

Referring to <FIG>, a first filter array <NUM> may include at least one unit filter having a center wavelength in a first wavelength range, and a second filter array <NUM> may include at least one unit filter having a center wavelength in a second wavelength range. <FIG> illustrates an example in which the first filter array <NUM> includes first, second, and third unit filters <NUM>, <NUM>, and <NUM>, and the second filter array <NUM> includes fourth, fifth, and sixth unit filters <NUM>, and <NUM>, and <NUM>.

Each of the first, second, and third unit filters <NUM>, <NUM>, and <NUM> constituting the first filter array <NUM> may include two first metal reflective layers <NUM> and <NUM> arranged spaced apart from each other and the first, second, and third cavities <NUM>, <NUM>, and <NUM> provided between the first metal reflective layers <NUM> and <NUM>. As the first metal reflective layers <NUM> and <NUM> are as described above, descriptions thereof are omitted.

The first, second, and third unit filters <NUM>, <NUM>, and <NUM> may have different center wavelengths in the first wavelength range. To this end, the first, second, and third unit filters <NUM>, <NUM>, and <NUM> may respectively include the first, second, and third cavities <NUM>, <NUM>, and <NUM> having different effective refractive indexes. Each of the first, second, and third cavities <NUM>, <NUM>, and <NUM> may include a first material layer and at least one second material layer arranged inside the first material layer and having a refractive index different from the first material layer.

<FIG> illustrates a case in which each of the first, second, and third cavities <NUM>, <NUM>, and <NUM> includes the first material layer and a plurality of second material layers arranged inside the first material layer parallel to each other and perpendicular to the first metal reflective layer <NUM>. Each of the first and second material layers may include, for example, silicon, a silicon oxide, a silicon nitride or a titanium oxide, and the like. The first material layer and the second material layer may have a relatively high contrast to control the effective refractive index of the cavities. For example, the first material layer may include a silicon oxide, and the second material layer may include a titanium oxide. However, embodiments are not limited thereto.

In the first, second, and third cavities <NUM>, <NUM>, and <NUM>, an effective refractive index may be changed by adjusting the width of the second material layer. <FIG> illustrates a case in which the second material layer has a width gradually increasing from the first cavity <NUM> to the third cavity <NUM>. For example, pitches of the second material layer may range from about <NUM> to <NUM>, and widths of the second material layer may be around <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>% of the pitches depending on the center wavelength of the unit filter. In this case, among the first, second, and third cavities <NUM>, <NUM>, and <NUM>, the third cavity <NUM> may have the highest effective refractive index, and the first cavity <NUM> may have the lowest effective refractive index. Among the first, second, and third unit filters <NUM>, <NUM>, and <NUM>, the third unit filter <NUM> may have the longest center wavelength, and the first unit filter <NUM> may have the shortest center wavelength. Furthermore, some unit filters may have a plurality of center wavelengths according to the thickness or effective refractive index of a cavity.

Although an example of a plurality of second material layers being arranged perpendicular to the first metal reflective layer <NUM> is described above, embodiments are not limited thereto, and the second material layers may be arranged parallel to the first metal reflective layer <NUM>.

Each of the fourth, fifth, and sixth unit filters <NUM>, and <NUM>, and <NUM> constituting the second filter array <NUM> may include the second metal reflective layers <NUM> and <NUM> arranged spaced apart from each other and fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> provided between the second metal reflective layers <NUM> and <NUM>. As the second metal reflective layers <NUM> and <NUM> are as described above, descriptions thereof are omitted.

The fourth, fifth, and sixth unit filters <NUM>, and <NUM>, and <NUM> may have different center wavelengths in the second wavelength range. To this end, the fourth, fifth, and sixth unit filters <NUM>, and <NUM>, and <NUM> may respectively include the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> having different effective refractive indexes. Each of the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> may include a first material layer and at least one second material layer arranged inside the first material layer and having a different refractive index from the first material layer.

<FIG> illustrates a case in which each of the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> includes the first material layer and a plurality of second material layers arranged inside the first material layer parallel to each other and perpendicular to the second metal reflective layer <NUM>. Each of the first and second material layers may include, for example, silicon, a silicon oxide, a silicon nitride or a titanium oxide, and the like.

In the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM>, an effective refractive index may be changed by adjusting the width of the second material layer. <FIG> illustrates a case in which the second material layer has a width gradually increasing from the fourth cavity <NUM> to the sixth cavity <NUM>. In this case, among the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM>, the sixth cavity <NUM> may have the highest effective refractive index, and the fourth cavity <NUM> may have the lowest effective refractive index. Among the fourth, fifth, and sixth unit filters <NUM>, and <NUM>, and <NUM>, the sixth unit filter <NUM> may have the longest center wavelength, and the fourth unit filter <NUM> may have the shortest center wavelength. Furthermore, some unit filters may have a plurality of center wavelengths according to the thickness or effective refractive index of a cavity.

A case in which both of the first filter array <NUM> and the second filter array <NUM> have a single cavity structure is described as an example. However, both of the first filter array <NUM> and the second filter array <NUM> may have a multi-cavity structure. Furthermore, one of the first filter array <NUM> and the second filter array <NUM> may have a single cavity structure, and the other may have a multi-cavity structure.

<FIG> is a schematic cross-sectional view of a spectral filter <NUM> according to another example embodiment. The spectral filter <NUM> of <FIG> is the same as the spectral filter <NUM> of <FIG>, except that a cavity further includes an etch stop layer.

First, second, and third unit filters <NUM>, <NUM>, and <NUM> constituting a first filter array <NUM> may include first, second, and third cavities <NUM>, <NUM>, and <NUM> having different effective refractive indexes. Each of the first, second, and third cavities <NUM>, <NUM>, and <NUM> may include an etch stop layer 740a provided on the first metal reflective layer <NUM>, a first material layer provided on the etch stop layer 740a, and at least one second material layer arranged inside the first material layer. The etch stop layer 740a may facilitate a patterning process for forming a cavity. Although the etch stop layer 740a may include, for example, a silicon oxide, titanium oxide, or hafnium oxide, and the like, embodiments are not limited thereto.

Fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> constituting the second filter array <NUM> may respectively include fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> having different effective refractive indexes. Each of the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> may include an etch stop layer 760a provided on the second metal reflective layers <NUM> and <NUM>, a first material layer provided on the etch stop layer 760a, and at least one second material layer arranged inside the first material layer.

<FIG> is a schematic cross-sectional view of a spectral filter <NUM> according to another example embodiment. The spectral filter <NUM> of <FIG> may be substantially the same as the spectral filter <NUM> of <FIG>, except that first and second dielectric layers <NUM> and <NUM> are respectively provided below and above first filter array <NUM>, and third and fourth dielectric layers <NUM> and <NUM> are respectively provided below and above a second filter array <NUM>.

Referring to <FIG>, first, second, and third unit filters <NUM>, <NUM>, and <NUM> constituting the first filter array <NUM> may include the first metal reflective layers <NUM> and <NUM> arranged spaced apart from each other, first, second, and third cavities <NUM>, <NUM>, and <NUM> provided between the first metal reflective layers <NUM> and <NUM>, and the first and second dielectric layers <NUM> and <NUM> respectively provided below and above the first, second, and third cavities <NUM>, <NUM>, and <NUM>. The first, second, and third unit filters <NUM>, <NUM>, and <NUM> may respectively include the first, second, and third cavities <NUM>, <NUM>, and <NUM> having different effective refractive indexes, to have different center wavelengths in the first wavelength range.

The first dielectric layer <NUM> may be provided below the first metal layer <NUM>, and the second dielectric layer <NUM> may be provided above the first metal layer <NUM>. The first and second dielectric layers <NUM> and <NUM> facilitate transmittance of the first, second, and third unit filters <NUM>, <NUM>, and <NUM>.

Each of the first and second dielectric layers <NUM> and <NUM> may include a first material layer and at least one second material layer arranged inside the first material layer and having a refractive index different from the first material layer. Each of the first and second material layers may include, for example, a titanium oxide, a silicon nitride, a hafnium oxide, a silicon oxide, a high index polymer, and the like, but embodiments are not limited thereto. Effective refractive indexes of the first and second dielectric layers <NUM> and <NUM> may be adjusted by changing the width of the second material layer according to the center wavelengths of the first, second, and third unit filters <NUM>, <NUM>, and <NUM>. Each of the first and second dielectric layers <NUM> and <NUM> may further include an etch stop layer.

Each of fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> constituting the second filter array <NUM> may include the second metal reflective layers <NUM> and <NUM> arranged spaced apart from each other, fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> provided between the second metal reflective layers <NUM> and <NUM>, and the third and fourth dielectric layers <NUM> and <NUM> respectively provided below and above fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM>. The fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> may respectively include the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> having different effective refractive indexes, to have different center wavelengths in the second wavelength range.

The third dielectric layer <NUM> may be provided below the second metal layer <NUM>, and the fourth dielectric layer <NUM> may be provided above the second metal layer <NUM>. Each of the third and fourth dielectric layers <NUM> and <NUM> may include a first material layer and at least one second material layer arranged inside the first material layer and having a different refractive index from the first material layer. Effective refractive indexes of the third and fourth dielectric layers <NUM> and <NUM> may be adjusted by changing the width of the second material layer according to the center wavelengths of the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM>. Each of the third and fourth dielectric layers <NUM> and <NUM> may further include an etch stop layer.

Referring to <FIG>, a first filter array <NUM> may include at least one unit filter having a center wavelength in a first wavelength range, and a second filter array <NUM> may include at least one unit filter having a center wavelength in a second wavelength range. <FIG> illustrates a case in which the first filter array <NUM> includes first, second, and third unit filters <NUM>, <NUM>, and <NUM>, and the second filter array <NUM> may include fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM>.

The first wavelength range may be shorter than the second wavelength range. For example, the first wavelength range may be a range of about <NUM> to about <NUM>, and the second wavelength range may be a range of about <NUM> to about <NUM>. However, this is merely exemplary, and the first and second wavelength ranges may be variously changed according to a design condition. For example, the first wavelength range may be longer than the second wavelength range.

Each of the first, second, and third unit filters <NUM>, <NUM>, and <NUM> constituting the first filter array <NUM>, which transmits light having a specific center wavelength in the first wavelength range, may have a Fabry-Perot structure in which cavities <NUM>, <NUM>, and <NUM> are provided between two metal reflective layers <NUM> and <NUM> spaced apart from each other.

When light passes through the metal reflective layers <NUM> and <NUM> to be incident on the first, second, and third cavities <NUM>, <NUM>, and <NUM>, the light may reciprocate between the metal reflective layers <NUM> and <NUM> inside the first, second, and third cavities <NUM>, <NUM>, and <NUM>, during which a constructive interference and a destructive interference occur. Light having a specific center wavelength and satisfying a constructive interference condition may exit to the outside of each of the first, second, and third unit filters <NUM>, <NUM>, and <NUM>. The wavelength band and the center wavelength of the light passing through the first, second, and third unit filters <NUM>, <NUM>, and <NUM> may be determined according to a reflection band of the metal reflective layers <NUM> and <NUM> and the characteristics of the first, second, and third cavities <NUM>, <NUM>, and <NUM>.

The metal reflective layers <NUM> and <NUM> may include a certain metal capable of reflecting light in the first wavelength range. When the first wavelength range is shorter than the second wavelength range, each of the metal reflective layers <NUM> and <NUM> may include, for example, Al, Ag, Au, TiN, and the like. When the first wavelength range is longer than the second wavelength range, the metal reflective layers <NUM> and <NUM> may include, for example, Cu, Ag, Au, TiN, and the like. However, this is merely exemplary. Although the metal reflective layers <NUM> and <NUM> may have a thickness of tens of nanometers, embodiments not limited thereto.

Although the first, second, and third cavities <NUM>, <NUM>, and <NUM> provided between the metal reflective layers <NUM> and <NUM> may include for example, silicon, a silicon oxide, a silicon nitride, or a titanium oxide, embodiments are not limited thereto. The first, second, and third unit filters <NUM>, <NUM>, and <NUM> may have different center wavelengths in the first wavelength range. To this end, the first, second, and third unit filters <NUM>, <NUM>, and <NUM> may respectively include the first, second, and third cavities <NUM>, <NUM>, and <NUM> having different thicknesses. Although not illustrated, as the first, second, and third unit filters <NUM>, <NUM>, and <NUM> include cavities having different effective refractive indexes, the first, second, and third unit filters <NUM>, <NUM>, and <NUM> may have different center wavelengths.

Each of the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> constituting the second filter array <NUM>, which transmits light having a specific center wavelength in the second wavelength range, may have a Fabry-Perot structure in which the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> are provided between two Bragg reflective layers <NUM> and <NUM> spaced apart from each other.

When light passes through the Bragg reflective layers <NUM> and <NUM> to be incident on the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM>, the light may reciprocate between the Bragg reflective layers <NUM> and <NUM> inside the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM>, during which a constructive interference and a destructive interference occur. Light having a specific center wavelength and satisfying a constructive interference condition may exit to the outside of each of the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM>. The wavelength band and the center wavelength of the light passing through the first, second, and third unit filters <NUM>, <NUM>, and <NUM> may be determined according to a reflection band of the Bragg reflective layers <NUM> and <NUM> and the characteristics of the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM>.

The Bragg reflective layers <NUM> and <NUM> may include a distributed Bragg reflector (DBR). Each of the Bragg reflective layers <NUM> and <NUM> may have a structure in which at least one of first material layers 951a and 952a having different refractive indexes and at least one of second material layers 951b and 952b are alternately stacked. The first material layers 951a and 952a or the second material layers 951b and 952b may include, for example, a silicon oxide, a titanium oxide, a silicon nitride, or silicon. However, embodiments are not limited thereto.

When any one of the first and second material layer 951a and 952a, and 951b and 952b constituting the Bragg reflective layers <NUM> and <NUM> includes a material, for example, silicon, and the like, capable of absorbing light in the first wavelength range, that is, light of a short wavelength, the light in the first wavelength range may be prevented from passing through the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM>.

Although the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> provided between the Bragg reflective layers <NUM> and <NUM> may include, for example, silicon, a silicon oxide, a silicon nitride, a hafnium oxide, or a titanium oxide, embodiments are not limited thereto.

The fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> may have different center wavelengths in the second wavelength range. To this end, the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> may include the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> having different thicknesses. As the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> include cavities having different effective refractive indexes, the fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> may have different center wavelengths.

As described above, as the first filter array <NUM> in which the first, second, and third cavities <NUM>, <NUM>, and <NUM> are provided between the metal reflective layers <NUM> and <NUM> and the second filter array <NUM> in which the fourth, fifth, and sixth cavities <NUM>, <NUM>, and <NUM> are provided between the Bragg reflective layers <NUM> and <NUM> are arranged on a plane, a spectral filter having the characteristics of a broadband including the first wavelength range and the second wavelength range may be implemented.

<FIG> is a schematic cross-sectional view of a spectral filter <NUM> according to another example embodiment. <FIG> illustrates a case in which, for convenience of explanation, a first filter array <NUM> includes one unit filter (a first unit filter <NUM>), and a second filter array <NUM> includes one unit filter (a second unit filter <NUM>).

Referring to <FIG>, the first unit filter <NUM> constituting the first filter array <NUM> may include two metal reflective layers <NUM> and <NUM> arranged spaced apart from each other and a first cavity <NUM> provided between the metal reflective layers <NUM> and <NUM>. The metal reflective layers <NUM> and <NUM> and the first cavity <NUM> are as described above.

The second unit filter <NUM> constituting the second filter array <NUM> may have a multi-cavity structure. For example, the second unit filter <NUM> may include three Bragg reflective layers <NUM>, <NUM>, and <NUM> arranged spaced apart from one another and two second cavities <NUM> and <NUM> provided between the Bragg reflective layers <NUM>, <NUM>, and <NUM>. The Bragg reflective layers <NUM>, <NUM>, and <NUM> and the second cavities <NUM> and <NUM> are as described above. The number of first and second material layers constituting each of the Bragg reflective layers <NUM>, <NUM>, and <NUM> may be variously changed. Although <FIG> illustrates a case of the second unit filter <NUM> including the second cavities <NUM> and <NUM>, embodiments are not limited thereto, and the second unit filter <NUM> may include three or more cavities.

<FIG> is a graph of a transmittance spectrum of the spectral filter <NUM> of <FIG>. <FIG> shows a transmittance spectrum of a case in which, in the spectral filter <NUM> of <FIG>, the first filter array <NUM> includes four unit filters having different center wavelengths and the second filter array <NUM> includes four unit filters having different center wavelengths.

In the first filter array <NUM>, the metal reflective layers <NUM> and <NUM> include Al, and the first cavity <NUM> includes a multi-layer film of TiO<NUM> and SiN. In the second filter array <NUM>, each of the Bragg reflective layers <NUM>, <NUM>, and <NUM> may include Si and SiO<NUM>, and the second cavities <NUM> and <NUM> include SiO<NUM>. In <FIG>, "S1" denotes a transmittance spectrum of the first filter array <NUM>, and "S2" denotes a transmittance spectrum of the second filter array <NUM>.

In the above description, a case in which the first unit filter <NUM> has a single cavity structure and the second unit filter <NUM> has a multi-cavity structure is described. However, the first unit filter <NUM> may have a multi-cavity structure and the second unit filter <NUM> may have a single cavity structure. Furthermore, both of the first and second unit filters <NUM> and <NUM> may have a multi-cavity structure.

Referring to <FIG>, the spectral filter <NUM> may include first and second filter arrays <NUM> and <NUM> and a microlens array <NUM> provided above the first and second filter arrays <NUM> and <NUM>. The first filter array <NUM> may include first, second, and third unit filters <NUM>, <NUM>, and <NUM> having center wavelengths in a first wavelength range, and the second filter array <NUM> may include fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> having center wavelengths in a second wavelength range.

The first filter array <NUM> may include any one of the above-described first filter arrays <NUM> to <NUM>, and the second filter array <NUM> may include any one of the above-described second filter arrays <NUM> to <NUM>. The descriptions of the first and second filter arrays <NUM> and <NUM> are omitted.

The microlens array <NUM> having a plurality of microlenses 1150a may be provided above the first and second filter arrays <NUM> and <NUM>. The microlenses 1150a may serve to focus external light to be incident on appropriate unit filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

<FIG> illustrates a case in which the microlenses 1150a are provided to have a one-to-one correspondence to the unit filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. However, this is merely exemplary, and at least two of the unit filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be provided corresponding to one microlens 1150a.

Referring to <FIG>, the spectral filter <NUM> may include first and second filter arrays <NUM> and <NUM> and a color filter array <NUM>. The first and second filter arrays <NUM> and <NUM> and the color filter array <NUM> may be arranged on substantially the same plane.

The first filter array <NUM> may include first, second, and third unit filters <NUM>, <NUM>, and <NUM> having center wavelengths in a first wavelength range, and the second filter array <NUM> may include fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> having center wavelengths in a second wavelength range. The first filter array <NUM> may include any one of the above-described first filter arrays <NUM> to <NUM>, and the second filter array <NUM> may include any one of the above-described second filter arrays <NUM> to <NUM>. The descriptions of the first and second filter arrays <NUM> and <NUM> are omitted.

The color filter array <NUM> may include, for example, a red color filter <NUM>, a green color filter <NUM>, and a blue color filter <NUM>. The red color filter <NUM> may transmit red light having a wavelength band of about <NUM> to about <NUM>, the green color filter <NUM> may transmit green light having a wavelength band of about <NUM> to about <NUM>, and the blue color filter <NUM> may transmit blue light having a wavelength band of about <NUM> to about <NUM>. For example, typical color filters applied to color display apparatuses such as liquid crystal display apparatuses, organic light-emitting display apparatuses, and the like may be used as the red, green and blue color filters <NUM>, <NUM>, and <NUM>. A microlens array <NUM> including a plurality of microlenses 1250a may be further provided above the first and second filter arrays <NUM> and <NUM> and the color filter array <NUM>.

According to an example embodiment, not only information about center wavelengths of the unit filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be obtained by using the first and second filter arrays <NUM> and <NUM>, but also information about wavelengths of the red, green, and blue light may be additionally obtained by using the color filter array <NUM>. The color filter array <NUM> may have a greater wavelength band than the first and second filter arrays <NUM> and <NUM>, and may improve the spectral resolution of the image.

Referring to <FIG>, the spectral filter <NUM> may include first and second filter array <NUM> and <NUM> and an additional filter array <NUM> provided on the first and second filter array <NUM> and <NUM>. The first filter array <NUM> may include first, second, and third unit filters <NUM>, <NUM>, and <NUM> having center wavelengths in a first wavelength range, and the second filter array <NUM> may include fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> having center wavelengths in a second wavelength range.

The first filter array <NUM> may include any one of the above-described first filter arrays <NUM> to <NUM>, and the second filter array <NUM> may include any one of the above-described second filter arrays <NUM> to <NUM>. The descriptions of the first and second filter array <NUM> and <NUM> are omitted.

The additional filter array <NUM> may include a plurality of first to third additional filters <NUM>, <NUM>, and <NUM>. <FIG> illustrates a case in which the first additional filter <NUM> is provided to correspond to the first and second unit filters <NUM> and <NUM>, the second additional filter <NUM> is provided to corresponding to the third and fourth unit filters <NUM> and <NUM>, and the third additional filter <NUM> is provided to correspond to the fifth and sixth unit filters <NUM> and <NUM>. However, this is merely exemplary, and each of the first, second, and third additional filters <NUM>, <NUM>, and <NUM> may be provided to correspond to one unit filter (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>) or three or more unit filters (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>).

Each of the first, second, and third additional filters <NUM>, <NUM>, and <NUM> may block light in a wavelength band that the corresponding unit filters (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>) do not desire. For example, when the first and second unit filters <NUM> and <NUM> have center wavelengths in a wavelength band of about <NUM> to about <NUM>, the first additional filter <NUM> may include a blue filter that transmits blue light. Furthermore, when the third and fourth unit filters <NUM> and <NUM> have center wavelengths in a wavelength band of about <NUM> to about <NUM>, the second additional filter <NUM> may include a green filter that transmits green light. When the fifth and sixth unit filters <NUM> and <NUM> have center wavelengths in a wavelength band of about <NUM> to about <NUM>, the third additional filter <NUM> may include red filter that transmits red light.

The additional filter array <NUM> may include a color filter array. In this case, the first, second, and third additional filters <NUM>, <NUM>, and <NUM> may respectively include blue, green, and red color filters. For example, typical color filters applied to color display apparatuses such as liquid crystal display apparatuses, organic light-emitting display apparatuses, and the like may be used as the blue, green, and red color filters.

The additional filter array <NUM> may include a broadband filter array. In this case, the first, second, and third additional filters <NUM>, <NUM>, and <NUM> may respectively include first, second, and third broadband filters. Each of the first, second, and third broadband filters may have, for example, a multi-cavity structure or a metal mirror structure.

<FIG> is a schematic cross-sectional view of a broadband filter <NUM> that is usable as the additional filter of <FIG> according to an example embodiment.

Referring to <FIG>, the broadband filter <NUM> may include a plurality of reflective layers <NUM>, <NUM>, and <NUM> arranged spaced apart from one another and a plurality of cavities <NUM> and <NUM> provided between the reflective layers <NUM>, <NUM>, and <NUM>. Although <FIG> illustrates an example of the three reflective layers <NUM>, <NUM>, and <NUM> and the two cavities <NUM> and <NUM>, the numbers of the reflective layers <NUM>, <NUM>, and <NUM> and the cavities <NUM> and <NUM> may be variously changed.

Each of the reflective layers <NUM>, <NUM>, and <NUM> may include a DBR. Each of the reflective layers <NUM>, <NUM>, and <NUM> may have a structure in which a plurality of material layers having different refractive indexes are alternately stacked. Each of the cavities <NUM> and <NUM> may include a material having a certain refractive index or two or more materials having different refractive indexes.

<FIG> is a schematic cross-sectional view of a broadband filter <NUM> that is usable as the first to third additional filters <NUM>, <NUM>, and <NUM> of <FIG>, according to another example embodiment.

Referring to <FIG>, the broadband filter <NUM> may include two metal mirror layers <NUM> and <NUM> arranged spaced apart from each other and a cavity <NUM> provided between the metal mirror layers <NUM> and <NUM>.

Referring to <FIG>, the spectral filter <NUM> may include first and second filter arrays <NUM> and <NUM>, and a short wavelength absorption filter <NUM> and a long wavelength cut-off filter <NUM> provided on the first and second filter arrays <NUM> and <NUM>.

The first filter array <NUM> may include first, second, and third unit filters <NUM>, <NUM>, and <NUM> having center wavelengths in a first wavelength range, and the second filter array <NUM> may include fourth, fifth, and sixth unit filters <NUM>, <NUM>, and <NUM> having center wavelengths in a second wavelength range.

The short wavelength absorption filter <NUM> may be provided in some unit filters (<NUM>, <NUM>, and <NUM>) of the first to sixth unit filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, and the long wavelength cut-off filter <NUM> may be provided in the other unit filters (<NUM>, <NUM>, and <NUM>) of the first to sixth unit filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. Although <FIG> illustrates a case in which each of the short wavelength absorption filter <NUM> and the long wavelength cut-off filter <NUM> is provided to correspond to one unit filter (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>), embodiments are not limited thereto, and each of the short wavelength absorption filter <NUM> and the long wavelength cut-off filter <NUM> may be provided to correspond to two or more unit filters (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>).

The short wavelength absorption filter <NUM> may cut off, for example, light of a short wavelength such as visible light. The short wavelength absorption filter <NUM> may be manufactured by depositing, for example, silicon that is a material for absorbing visible light, on some unit filters (<NUM>, <NUM>, and <NUM>) of the first to sixth unit filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The unit filters (<NUM>, <NUM>, and <NUM>) where the short wavelength absorption filter <NUM> is provided may transmit near infrared (NIR) light having a wavelength longer than the visible light.

The long wavelength cut-off filter <NUM> may cut off, for example, light having a long wavelength such as NIR light. The long wavelength cut-off filter <NUM> may include a NIR light cut-off filter. The unit filters (<NUM>, <NUM>, and <NUM>) where the long wavelength cut-off filter <NUM> is provided may transmit visible light having a wavelength shorter than NIR light.

According to an example embodiment, as the short wavelength absorption filter <NUM> and the long wavelength cut-off filter <NUM> are provided on the first and second filter arrays <NUM> and <NUM>, the spectral filter <NUM> having the broadband characteristics capable implementing from a visible light band to an NIR band may be manufactured.

<FIG> is a plan view of an example of a spectral filter <NUM> that is applicable to the image sensor <NUM> of <FIG>.

Referring to <FIG>, the spectral filter <NUM> may include a plurality of filter groups <NUM> arranged in two dimensions. Each of the filter groups <NUM> may include sixteen unit filters F1 to F16 arranged in a <NUM>×<NUM> array.

The first and second unit filters F1 and F2 may have center wavelengths UV1 and UV2 in an ultraviolet range, and the third to fifth unit filters F3 to F5 may have center wavelengths B1 to B3 in a blue light range. The sixth to eleventh unit filter F6 to F11 may have center wavelengths G1 to G6 in a green light range, and the twelfth to fourteenth unit filters F12 to F14 may have center wavelengths R1 to R3 in a red light range. The fifteenth and sixteenth unit filters F15 and F16 may have center wavelengths NIR1 and NIR2 in a near infrared range.

<FIG> is a plan view of another example of the spectral filter <NUM> that is applicable to the image sensor <NUM> of <FIG>. <FIG> is a plan view of one filter group <NUM>, for convenience of explanation.

Referring to <FIG>, each filter group <NUM> may include nine unit filters F1 to F9 arranged in a <NUM>×<NUM> array. The first and second unit filters F1 and F2 may have center wavelengths UV1 and UV2 in the ultraviolet range, and the fourth, fifth, and seventh unit filter F4, F5, and F7 may have center wavelengths B1 to B3 in the blue light range. The third and sixth unit filters F3 and F6 may have center wavelengths G1 and G2 in the green light range, and the eighth and ninth unit filters F8 and F9 may have center wavelengths R1 and R2 in the red light range.

Referring to <FIG>, each filter group <NUM> may include twenty-five unit filters F1 to F25 arranged in a <NUM>×<NUM> array. The first to third unit filter F1 to F3 may have center wavelengths UV1 to UV3 in the ultraviolet range, and the sixth, seventh, eighth, eleventh, and twelfth unit filters F6, F7, F8, F11, and F12 may have center wavelengths B1 to B5 in the blue light range. The fourth, fifth, and ninth unit filters F4, F5, and F9 may have center wavelengths G1 to G3 in the green light range, and the tenth, thirteenth, fourteenth, fifteenth, eighteenth, and nineteenth unit filters F10, F13, F14, F15, F18, and F19 may have center wavelengths R1 to R6 in a red light range. The twentieth, twenty-third twenty-fourth, and twenty-fifth unit filters F20, F23, F24, and F25 may have center wavelengths NIR1 to NIR4 in the near infrared range.

The image sensor <NUM> having the above-described spectral filter may be employed in various high performance optical devices or high performance electronic devices. The electronic devices may include, for example, smart phones, mobile phones, cellular phones, personal digital assistants (PDAs), laptop computers, personal computers (PCs), various portable devices, home appliances, security cameras, medical cameras, automobiles, Internet of Things (IoT) devices, and other mobile or no-mobile computing devise, but embodiments are not limited thereto.

The electronic devices may further include, in addition to the image sensor <NUM>, a processor for controlling an image sensor, for example, an application processor (AP), control a number of hardware or software constituent elements by driving operating systems or application programs through the processor, and perform various data processing and calculations. The processors may further include graphics processing units (GPUs) and/or image signal processors. When the processors include image signal processors, an image (or video) obtained through an image sensor may be store and/or output using the processor.

<FIG> is a schematic block diagram of an electronic device ED01 including the image sensor <NUM>, according to an embodiment. Referring to <FIG>, in a network environment ED00, the electronic device ED01 may communicate with another electronic device ED02 through a first network ED98 (short-range wireless communication network, and the like), or communicate with another electronic device ED04 and/or a server ED08 through a second network ED99 (long-range wireless communication network, and the like). The electronic device ED01 may communicate with the electronic device ED04 through the server ED08. The electronic device ED01 may include a processor ED20, a memory ED30, an input device ED50, an audio output device ED55, a display apparatus ED60, an audio module ED70, a sensor module ED76, an interface ED77, a haptic module ED79, a camera module ED80, a power management module ED88, a battery ED89, a communication module ED90, a subscriber identification module ED96, and/or an antenna module ED97. In the electronic device ED01, some (the display apparatus ED60, and the like) of constituent elements may be omitted or other constituent elements may be added. Some of the constituent elements may be implemented by one integrated circuit. For example, the sensor module ED76 (a fingerprint sensor, an iris sensor, an illuminance sensor, and the like) may be implemented by being embedded in the display apparatus ED60 (a display, and the like). Furthermore, when the image sensor <NUM> includes a spectral function, some functions (a color sensor and an illuminance sensor) of the sensor module ED76 may be implemented by the image sensor <NUM>, not by a separate sensor module.

The processor ED20 may control one or a plurality of other constituent elements (hardware and software constituent elements, and the like) of the electronic device ED01 connected to the processor ED20 by executing software (a program ED40, and the like), and perform various data processing or calculations. As part of the data processing or calculations, the processor ED20 may load, in a volatile memory ED32, commands and/or data received from other constituent elements (the sensor module ED76, the communication module ED90, and the like), process the command and/or data stored in the volatile memory ED32, and store result data in a non-volatile memory ED34. The processor ED20 may include a main processor ED21 (a central processing unit, an application processor, and the like) and an auxiliary processor ED23 (a graphics processing unit, an image signal processor, a sensor hub processor, a communication processor, and the like) that is operable independently of or together with the main processor ED21. The auxiliary processor ED23 may use less power than the main processor ED21 and may perform a specialized function.

Instead of the main processor ED21 when the main processor ED21 is in an inactive state (sleep state), or with the main processor ED21 when the main processor ED21 is in an active state (application execution state), the auxiliary processor ED23 may control functions and/or states related to some constituent elements (the display apparatus ED60, the sensor module ED76, the communication module ED90, and the like) of the constituent elements of the electronic device ED01. The auxiliary processor ED23 (an image signal processor, a communication processor, and the like) may be implemented as a part of functionally related other constituent elements (the camera module ED80, the communication module ED90, and the like).

The memory ED30 may store various data needed by the constituent elements (the processor ED20, the sensor module ED76, and the like) of the electronic device ED01. The data may include, for example, software (the program ED40, and the like) and input data and/or output data about commands related thereto. The memory ED30 may include the volatile memory ED32 and/or the non-volatile memory ED34. The non-volatile memory ED34 may include an internal memory ED36 fixedly installed in the electronic device ED01 and an external memory ED38 that is removable.

The program ED40 may be stored in the memory ED30 as software, and may include an operating system ED42, middleware ED44, and/or an application ED46.

The input device ED50 may receive commands and/or data to be used for constituent elements (the processor ED20, and the like) of the electronic device ED01, from the outside (a user, and the like) of the electronic device ED01. The input device ED50 may include a microphone, a mouse, a keyboard, and/or a digital pen (a stylus pen, and the like).

The audio output device ED55 may output an audio signal to the outside of the electronic device ED01. The audio output device ED55 may include a speaker and/or a receiver. The speaker may be used for general purposes such as multimedia playback or recording playback, and the receiver can be used to receive incoming calls. The receiver may be implemented by being coupled as a part of the speaker or by an independent separate device.

The display apparatus ED60 may visually provide information to the outside of the electronic device ED01. The display apparatus ED60 may include a display, a hologram device, or a projector, and a control circuit to control a corresponding device. The display apparatus ED60 may include a touch circuitry set to detect a touch and/or a sensor circuit (a pressure sensor, and the like) set to measure the strength of a force generated by the touch.

The audio module ED70 may convert sound into electrical signals or reversely electrical signals into sound. The audio module ED70 may obtain sound through the input device ED50, or output sound through a speaker and/or a headphone of another electronic device (the electronic device ED02, and the like) connected to the audio output device ED55 and/or the electronic device ED01 in a wired or wireless manner.

The sensor module ED76 may detect an operation state (power, temperature, and the like) of the electronic device ED01, or an external environment state (a user state, and the like), and generate an electrical signal and/or a data value corresponding to a detected state. The sensor module ED76 may include a gesture sensor, a gyro sensor, a barometric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an IR sensor, a biometric sensor, a temperature sensor, a humidity sensor, and/or an illuminance sensor.

The interface ED77 may support one or a plurality of specified protocols used for the electronic device ED01 to be connected to another electronic device (the electronic device ED02, and the like) in a wired or wireless manner. The interface ED77 may include a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, an SD card interface, and/or an audio interface.

A connection terminal ED78 may include a connector for the electronic device ED01 to be physically connected to another electronic device (the electronic device ED02, and the like). The connection terminal ED78 may include an HDMI connector, a USB connector, an SD card connector, and/or an audio connector (a headphone connector, and the like).

The haptic module ED79 may convert electrical signals into mechanical stimuli (vibrations, movements, and the like) or electrical stimuli that are perceivable by a user through tactile or motor sensations. The haptic module ED79 may include a motor, a piezoelectric device, and/or an electrical stimulation device.

The camera module ED80 may capture a still image and a video. The camera module ED80 may include a lens assembly including one or a plurality of lenses, the image sensor <NUM> of <FIG>, image signal processors, and/or flashes. The lens assembly included in the camera module ED80 may collect light emitted from a subject for image capturing.

The power management module ED88 may manage power supplied to the electronic device ED01. The power management module ED88 may be implemented as a part of a power management integrated circuit (PMIC).

The battery ED89 may supply power to the constituent elements of the electronic device ED01. The battery ED89 may include non-rechargeable primary cells, rechargeable secondary cells, and/or fuel cells.

The communication module ED90 may establish a wired communication channel and/or a wireless communication channel between the electronic device ED01 and another electronic device (the electronic device ED02, the electronic device ED04, the server ED08, and the like), and support a communication through an established communication channel. The communication module ED90 may be operated independent of the processor ED20 (the application processor, and the like), and may include one or a plurality of communication processors supporting a wired communication and/or a wireless communication. The communication module ED90 may include a wireless communication module ED92 (a cellular communication module, a short-range wireless communication module, a global navigation satellite system (GNSS) communication module, and the like), and/or a wired communication module ED94 (a local area network (LAN) communication module, a power line communication module, and the like). Among the above communication modules, a corresponding communication module may communicate with another electronic device through the first network ED98 (a short-range communication network such as Bluetooth, WiFi Direct, or infrared data association (IrDA)) or the second network ED99 (a long-range communication network such as a cellular network, the Internet, or a computer network (LAN, WAN, and the like)). These various types of communication modules may be integrated into one constituent element (a single chip, and the like), or may be implemented as a plurality of separate constituent elements (multiple chips). The wireless communication module ED92 may verify and authenticate the electronic device ED01 in a communication network such as the first network ED98 and/or the second network ED99 by using subscriber information (an international mobile subscriber identifier (IMSI), and the like) stored in the subscriber identification module ED96.

The antenna module ED97 may transmit signals and/or power to the outside (another electronic device, and the like) or receive signals and/or power from the outside. An antenna may include an emitter formed in a conductive pattern on a substrate (a printed circuit board (PCB), and the like). The antenna module ED97 may include one or a plurality of antennas. When the antenna module ED97 includes a plurality of antennas, the communication module ED90 may select, from among the antennas, an appropriate antenna for a communication method used in a communication network such as the first network ED98 and/or the second network ED99. Signals and/or power may be transmitted or received between the communication module ED90 and another electronic device through the selected antenna. Other parts (an RFIC, and the like) than the antenna may be included as a part of the antenna module ED97.

Some of the constituent elements may be connected to each other through a communication method between peripheral devices (a bus, general purpose input and output (GPIO), a serial peripheral interface (SPI), a mobile industry processor interface (MIPI), and the like) and may mutually exchange signals (commands, data, and the like).

The command or data may be transmitted or received between the electronic device ED01 and the external electronic device ED04 through the server ED08 connected to the second network ED99. The electronic devices ED02 and ED04 may be of a type that is the same as or different from the electronic device ED01. All or a part of operations executed in the electronic device ED01 may be executed in one or a plurality of the electronic devices (ED02, ED04, and ED08). For example, when the electronic device ED01 needs to perform a function or service, the electronic device ED01 may request one or a plurality of electronic devices to perform part of the whole of the function or service, instead of performing the function or service. The one or a plurality of the electronic devices receiving the request may perform additional function or service related to the request, and transmit a result of the performance to the electronic device ED01. To this end, cloud computing, distributed computing, and/or client-server computing technology may be used.

<FIG> is a schematic block diagram of the camera module ED80 of <FIG>. Referring to <FIG>, the camera module ED80 may include a lens assembly CM10, a flash CM20, the image sensor <NUM> (the image sensor <NUM> of <FIG>, and the like), an image stabilizer CM40, a memory CM50 (a buffer memory, and the like), and/or an image signal processor CM60. The lens assembly CM10 may collect light emitted from a subject for image capturing. The camera module ED80 may include a plurality of lens assemblies CM10, and in this case, the camera module ED80 may include a dual camera, a <NUM> degrees camera, or a spherical camera. Some of the lens assemblies CM10 may have the same lens attributes (a viewing angle, a focal length, auto focus, F Number, optical zoom, and the like), or different lens attributes. The lens assembly CM10 may include a wide angle lens or a telescopic lens.

The flash CM20 may emit light used to reinforce light emitted or reflected from a subject. The flash CM20 may include one or a plurality of light-emitting diodes (a red-green-blue (RGB) LED, a white LED, an infrared LED, an ultraviolet LED, and the like), and/or a xenon lamp. The image sensor <NUM> may include the image sensor of <FIG>, and convert light emitted or reflected from the subject and transmitted through the lens assembly CM10 into electrical signals, thereby obtaining an image corresponding to the subject. The image sensor <NUM> may include one or a plurality of sensors selected from image sensors having different attributes such as an RGB sensor, a black and white (BW) sensor, an IR sensor, or UV sensor. Each sensor included in the image sensor <NUM> may be implemented by a charged coupled device (CCD) sensor and/or a complementary metal oxide semiconductor (CMOS) sensor.

The image stabilizer CM40 may move, in response to a movement of the camera module ED80 or an electronic device ED01 including the same, one or a plurality of lenses included in the lens assembly CM10 or the image sensor <NUM> in a particular direction or may compensate a negative effect due to the movement by controlling (adjusting a read-out timing, and the like) the movement characteristics of the image sensor <NUM>. The image stabilizer CM40 may detect a movement of the camera module ED80 or the electronic device ED01 by using a gyro sensor (not shown) or an acceleration sensor (not shown) arranged inside or outside the camera module ED80. The image stabilizer CM40 may be implemented in an optical form.

The memory CM50 may store a part or entire data of an image obtained through the image sensor <NUM> for a subsequent image processing operation. For example, when a plurality of images are obtained at high speed, only low resolution images are displayed while the obtained original data (Bayer-Patterned data, high resolution data, and the like) is stored in the memory CM50. Then, the memory CM50 may be used to transmit the original data of a selected (user selection, and the like) image to the image signal processor CM60. The memory CM50 may be incorporated into the memory ED30 of the electronic device ED01, or configured to be an independently operated separate memory.

The image signal processor CM60 may perform image processing on the image obtained through the image sensor <NUM> or the image data stored in the memory CM50. The image processing may include depth map generation, three-dimensional modeling, panorama generation, feature point extraction, image synthesis, and/or image compensation (noise reduction, resolution adjustment, brightness adjustment, blurring, sharpening, softening, and the like). The image signal processor CM60 may perform control (exposure time control, or read-out timing control, and the like) on constituent elements (the image sensor <NUM>, and the like) included in the camera module ED80. The image processed by the image signal processor CM60 may be stored again in the memory CM50 for additional processing or provided to external constituent elements (the memory ED30, the display apparatus ED60, the electronic device ED02, the electronic device ED04, the server ED08, and the like) of the camera module ED80. The image signal processor CM60 may be incorporated into the processor ED20, or configured to be a separate processor operated independently of the processor ED20. When the image signal processor CM60 is configured by a separate processor from the processor ED20, the image processed by the image signal processor CM60 may undergo additional image processing by the processor ED20 and then displayed through the display apparatus ED60.

The electronic device ED01 may include a plurality of camera modules ED80 having different attributes or functions. In this case, one of the camera modules ED80 may be a wide angle camera, and another may be a telescopic camera. Similarly, one of the camera modules ED80 may be a front side camera, and another may be a read side camera.

The image sensor <NUM> according to embodiments may be applied to a mobile phone or smartphone <NUM> illustrated in <FIG>, a tablet or smart tablet <NUM> illustrated in <FIG>, a digital camera or camcorder <NUM> illustrated in <FIG>, a notebook computer <NUM> illustrated in <FIG>, a television or smart television <NUM> illustrated in <FIG>, and the like. For example, the smartphone <NUM> or the smart tablet <NUM> may include a plurality of high resolution cameras, each having a high resolution image sensor mounted thereon. Depth information of subjects in an image may be extracted by using a high resolution cameras, out focusing of the image may be adjusted, or subjects in the image may be automatically identified.

Furthermore, the image sensor <NUM> may be applied to a smart refrigerator <NUM> illustrated in <FIG>, a security camera <NUM> illustrated in <FIG>, a robot <NUM> illustrated in <FIG>, a medical camera <NUM> illustrated in <FIG>, and the like. For example, the smart refrigerator <NUM> may automatically recognize food in a refrigerator, by using an image sensor, and notify a user of the presence of a particular food, the type of food that is input or output, and the like, through a smartphone. The security camera <NUM> may provide an ultrahigh resolution image and may recognize an object or a person in an image in a dark environment by using high sensitivity. The robot <NUM> may be provided in a disaster or industrial site that is not directly accessible by people, and may provide a high resolution image. The medical camera <NUM> may provide a high resolution image for diagnosis or surgery, and thus a field of vision may be dynamically adjusted.

Furthermore, the image sensor <NUM> may be applied to a vehicle <NUM> as illustrated in <FIG>. The vehicle <NUM> may include a plurality of vehicle cameras <NUM>, <NUM>, <NUM>, and <NUM> arranged at various positions. Each of the vehicle cameras <NUM>, <NUM>, <NUM>, and <NUM> may include an image sensor according to an embodiment. The vehicle <NUM> may provide a driver with various pieces of information about the inside or periphery of the vehicle <NUM>, by using the vehicle cameras <NUM>, <NUM>, <NUM>, and <NUM>, and thus an object or a person in an image may be automatically recognized and information needed for autonomous driving is provided.

Descriptions of features or aspects within each example embodiment should typically be considered as available for other similar features or aspects in other embodiments.

Claim 1:
A spectral filter (<NUM>; <NUM>; <NUM>) comprising:
a first unit filter (<NUM>; <NUM>) having a first center wavelength in a first wavelength range; and
a second unit filter (<NUM>; <NUM>) having a second center wavelength in a second wavelength range,
wherein the first unit filter (<NUM>; <NUM>) comprises:
two first metal reflective layers (<NUM>, <NUM>) provided spaced apart from each other and comprising a first metal; and
a first cavity (<NUM>) provided between the two first metal reflective layers (<NUM>, <NUM>), and
wherein the second unit filter (<NUM>; <NUM>) comprises:
two second metal reflective layers (<NUM>, <NUM>) provided spaced apart from each other and comprising a second metal different from the first metal; and
a second cavity (<NUM>) provided between the two second metal reflective layers (<NUM>, <NUM>),
wherein the first unit filter (<NUM>; <NUM>) and the second unit filter (<NUM>; <NUM>) are provided in one dimension or two dimensions on a plane;
the spectral filter (<NUM>; <NUM>; <NUM>) characterized in that
the first unit filter (<NUM>; <NUM>) is included in a first filter array (<NUM>; <NUM>; <NUM>) comprising a plurality of first unit filters (<NUM>-<NUM>; <NUM>-<NUM>; <NUM>) having different center wavelengths in the first wavelength range, and
the second unit filter (<NUM>; <NUM>) is included in a second filter array (<NUM>; <NUM>; <NUM>) comprising a plurality of second unit filters (<NUM>-<NUM>; <NUM>-<NUM>; <NUM>) having different center wavelengths in the second wavelength range,
wherein each of the first unit filters (<NUM>-<NUM>; <NUM>-<NUM>; <NUM>) included in the first filter array (<NUM>; <NUM>; <NUM>) and each of the second unit filters (<NUM>-<NUM>; <NUM>-<NUM>; <NUM>) included in the second filter array (<NUM>; <NUM>; <NUM>) comprises a cavity (<NUM>-<NUM>, <NUM>-<NUM>; <NUM>, <NUM>) and the cavities (<NUM>-<NUM>, <NUM>-<NUM>; <NUM>, <NUM>) having different thicknesses or effective indexes, in particular, the thickness or the effective index of the cavities (<NUM>-<NUM>, <NUM>-<NUM>; <NUM>, <NUM>) with respect to each of the first filter array (<NUM>; <NUM>; <NUM>) and the second filter array (<NUM>; <NUM>; <NUM>) is subsequently increased.