Optical filters and image sensors and camera modules and electronic devices
An optical filter includes a light absorbing layer and a conductive nanodisk. The light absorbing layer includes a near-infrared absorbing material configured to absorb light of a first wavelength spectrum within a near-infrared wavelength spectrum. The conductive nanodisk is configured to absorb or reflect light of a second wavelength spectrum within the first wavelength spectrum. An image sensor includes the optical filter, a camera module includes the optical filter, and an electronic device includes the optical filter.
1. An optical filter, comprising:
a light absorbing layer including a near-infrared absorbing material configured to absorb light of a first wavelength spectrum, the first wavelength spectrum encompassed within a near-infrared wavelength spectrum; and
a conductive nanodisk configured to absorb, reflect, or scatter light of a second wavelength spectrum, the second wavelength spectrum at least partially overlapping the first wavelength spectrum such that the second wavelength spectrum at least partially overlaps the near-infrared wavelength spectrum.
2. The optical filter of claim 1 , wherein the light absorbing layer is in contact with at least one of a lower surface, an upper surface, or a side surface of the conductive nanodisk.
3. The optical filter of claim 1 , wherein the conductive nanodisk is a metal nanodisk, such that the conductive nanodisk includes a metal material.
4. The optical filter of claim 1 , wherein a ratio of a diameter of the conductive nanodisk to a thickness of the conductive nanodisk is greater than or equal to about 8.
5. The optical filter of claim 1 , wherein a diameter of the conductive nanodisk is about 80 nm to about 300 nm.
6. The optical filter of claim 5 , wherein a thickness of the conductive nanodisk is about 1 nm to about 20 nm.
7. The optical filter of claim 1 , wherein
a transmission spectrum of the near-infrared absorbing material has a first minimum transmission wavelength that is within the first wavelength spectrum,
a transmission spectrum of the conductive nanodisk has a second minimum transmission wavelength that is within the second wavelength spectrum, and
the first minimum transmission wavelength and the second minimum transmission wavelength are both within a wavelength spectrum of about 700 nm to about 990 nm.
8. The optical filter of claim 7 , wherein a difference between the first minimum transmission wavelength and the second minimum transmission wavelength is less than or equal to about 100 nm.
9. The optical filter of claim 1 , wherein a transmission spectrum of the optical filter overlaps both the first wavelength spectrum and the second wavelength spectrum and has a wavelength width that is wider than each of the first wavelength spectrum and the second wavelength spectrum.
10. The optical filter of claim 9 , wherein the wavelength width of the transmission spectrum of the optical filter at 50% transmittance is greater than or equal to about 100 nm.
11. The optical filter of claim 1 , wherein a ratio of an average transmittance of the optical filter in the near-infrared wavelength spectrum relative to an average transmittance of the optical filter in a visible wavelength spectrum is less than or equal to about 0.18.
12. The optical filter of claim 1 , wherein
an average transmittance of the optical filter in a wavelength spectrum of about 430 nm to about 565 nm is greater than or equal to about 80%, and
an average transmittance of the optical filter in a wavelength spectrum of about 700 nm to about 800 nm or about 890 nm to about 990 nm is less than or equal to about 20%.
13. The optical filter of claim 12 , wherein an average reflectance of the optical filter in the wavelength spectrum of about 700 nm to about 800 nm or about 890 nm to about 990 nm is less than or equal to about 30%.
14. The optical filter of claim 1 , wherein a surface coverage of the conductive nanodisk is about 5% to about 50% of a total area of the optical filter.
15. The optical filter of claim 1 , further comprising:
a binder or a cured product thereof,
wherein the conductive nanodisk is included in the optical filter in an amount of about 5 wt % to about 30 wt % based on a total weight of the conductive nanodisk, the near-infrared absorbing material, and the binder or the cured product thereof.
16. A camera comprising the optical filter of claim 1 .
17. An electronic device comprising the camera of claim 16 .
18. An image sensor, comprising:
a semiconductor substrate including a plurality of photodiodes, and
the optical filter of claim 1 on the semiconductor substrate.
19. The image sensor of claim 18 , further comprising:
a color filter layer below or above the optical filter.
20. A camera comprising the image sensor of claim 18 .
21. An electronic device comprising the camera of claim 20 .
22. An optical filter, comprising:
a light absorbing layer including a light absorbing material configured to absorb light of a first wavelength spectrum; and
a conductive nanodisk configured to absorb, reflect, or scatter light of a second wavelength spectrum, the second wavelength spectrum at least partially overlapping the first wavelength spectrum.
23. The optical filter of claim 22 , wherein the light absorbing layer includes a near-infrared absorbing material, and the first wavelength spectrum is encompassed within a near-infrared wavelength spectrum, such that the second wavelength spectrum at least partially overlaps the near-infrared wavelength spectrum.
24. The optical filter of claim 22 , wherein the light absorbing layer is in contact with at least one of a lower surface, an upper surface, or a side surface of the conductive nanodisk.
25. The optical filter of claim 22 , wherein the conductive nanodisk is a metal nanodisk, such that the conductive nanodisk includes a metal material.
26. The optical filter of claim 22 , wherein a ratio of a diameter of the conductive nanodisk to a thickness of the conductive nanodisk is greater than or equal to about 8.
27. The optical filter of claim 22 , wherein a diameter of the conductive nanodisk is about 80 nm to about 300 nm.
28. The optical filter of claim 27 , wherein a thickness of the conductive nanodisk is about 1 nm to about 20 nm.
29. The optical filter of claim 22 , wherein
a transmission spectrum of the light absorbing material has a first minimum transmission wavelength that is within the first wavelength spectrum,
a transmission spectrum of the conductive nanodisk has a second minimum transmission wavelength that is within the second wavelength spectrum, and
a difference between the first minimum transmission wavelength and the second minimum transmission wavelength is less than or equal to about 100 nm.
30. The optical filter of claim 22 , wherein a transmission spectrum of the optical filter overlaps both the first wavelength spectrum and the second wavelength spectrum and has a wavelength width that is wider than each of the first wavelength spectrum and the second wavelength spectrum.
31. The optical filter of claim 30 , wherein the wavelength width of the transmission spectrum of the optical filter at 50% transmittance is greater than or equal to about 100 nm.