High-Identical Numerical Aperture, Multifocal Microlens Array through Single-Step Multi-Sized Hole Patterning Photolithography
Imaging applications based on microlens arrays (MLAs) have a great potential for the depth sensor, wide field-of-view camera and the reconstructed hologram. However, the narrow depth-of-field remains the challenge for accurate, reliable depth estimation. Multifocal microlens array (Mf-MLAs) is perce...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2020-11-01
|
| Series: | Micromachines |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2072-666X/11/12/1068 |
| _version_ | 1797546187063033856 |
|---|---|
| author | Joong Hoon Lee Sehui Chang Min Seok Kim Yeong Jae Kim Hyun Myung Kim Young Min Song |
| author_facet | Joong Hoon Lee Sehui Chang Min Seok Kim Yeong Jae Kim Hyun Myung Kim Young Min Song |
| author_sort | Joong Hoon Lee |
| collection | DOAJ |
| description | Imaging applications based on microlens arrays (MLAs) have a great potential for the depth sensor, wide field-of-view camera and the reconstructed hologram. However, the narrow depth-of-field remains the challenge for accurate, reliable depth estimation. Multifocal microlens array (Mf-MLAs) is perceived as a major breakthrough, but existing fabrication methods are still hindered by the expensive, low-throughput, and dissimilar numerical aperture (NA) of individual lenses due to the multiple steps in the photolithography process. This paper reports the fabrication method of high NA, Mf-MLAs for the extended depth-of-field using single-step photolithography assisted by chemical wet etching. The various lens parameters of Mf-MLAs are manipulated by the multi-sized hole photomask and the wet etch time. Theoretical and experimental results show that the Mf-MLAs have three types of lens with different focal lengths, while maintaining the uniform and high NA irrespective of the lens type. Additionally, we demonstrate the multi-focal plane image acquisition via Mf-MLAs integrated into a microscope. |
| first_indexed | 2024-03-10T14:26:31Z |
| format | Article |
| id | doaj.art-bcc1a8c3e39349dda059cc5715422c6c |
| institution | Directory Open Access Journal |
| issn | 2072-666X |
| language | English |
| last_indexed | 2024-03-10T14:26:31Z |
| publishDate | 2020-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Micromachines |
| spelling | doaj.art-bcc1a8c3e39349dda059cc5715422c6c2023-11-20T22:59:48ZengMDPI AGMicromachines2072-666X2020-11-011112106810.3390/mi11121068High-Identical Numerical Aperture, Multifocal Microlens Array through Single-Step Multi-Sized Hole Patterning PhotolithographyJoong Hoon Lee0Sehui Chang1Min Seok Kim2Yeong Jae Kim3Hyun Myung Kim4Young Min Song5School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, KoreaSchool of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, KoreaSchool of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, KoreaSchool of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, KoreaSchool of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, KoreaSchool of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, KoreaImaging applications based on microlens arrays (MLAs) have a great potential for the depth sensor, wide field-of-view camera and the reconstructed hologram. However, the narrow depth-of-field remains the challenge for accurate, reliable depth estimation. Multifocal microlens array (Mf-MLAs) is perceived as a major breakthrough, but existing fabrication methods are still hindered by the expensive, low-throughput, and dissimilar numerical aperture (NA) of individual lenses due to the multiple steps in the photolithography process. This paper reports the fabrication method of high NA, Mf-MLAs for the extended depth-of-field using single-step photolithography assisted by chemical wet etching. The various lens parameters of Mf-MLAs are manipulated by the multi-sized hole photomask and the wet etch time. Theoretical and experimental results show that the Mf-MLAs have three types of lens with different focal lengths, while maintaining the uniform and high NA irrespective of the lens type. Additionally, we demonstrate the multi-focal plane image acquisition via Mf-MLAs integrated into a microscope.https://www.mdpi.com/2072-666X/11/12/1068optical MEMSmicrolens arraymultiple focal lengthsthree-dimensional imaging |
| spellingShingle | Joong Hoon Lee Sehui Chang Min Seok Kim Yeong Jae Kim Hyun Myung Kim Young Min Song High-Identical Numerical Aperture, Multifocal Microlens Array through Single-Step Multi-Sized Hole Patterning Photolithography Micromachines optical MEMS microlens array multiple focal lengths three-dimensional imaging |
| title | High-Identical Numerical Aperture, Multifocal Microlens Array through Single-Step Multi-Sized Hole Patterning Photolithography |
| title_full | High-Identical Numerical Aperture, Multifocal Microlens Array through Single-Step Multi-Sized Hole Patterning Photolithography |
| title_fullStr | High-Identical Numerical Aperture, Multifocal Microlens Array through Single-Step Multi-Sized Hole Patterning Photolithography |
| title_full_unstemmed | High-Identical Numerical Aperture, Multifocal Microlens Array through Single-Step Multi-Sized Hole Patterning Photolithography |
| title_short | High-Identical Numerical Aperture, Multifocal Microlens Array through Single-Step Multi-Sized Hole Patterning Photolithography |
| title_sort | high identical numerical aperture multifocal microlens array through single step multi sized hole patterning photolithography |
| topic | optical MEMS microlens array multiple focal lengths three-dimensional imaging |
| url | https://www.mdpi.com/2072-666X/11/12/1068 |
| work_keys_str_mv | AT joonghoonlee highidenticalnumericalaperturemultifocalmicrolensarraythroughsinglestepmultisizedholepatterningphotolithography AT sehuichang highidenticalnumericalaperturemultifocalmicrolensarraythroughsinglestepmultisizedholepatterningphotolithography AT minseokkim highidenticalnumericalaperturemultifocalmicrolensarraythroughsinglestepmultisizedholepatterningphotolithography AT yeongjaekim highidenticalnumericalaperturemultifocalmicrolensarraythroughsinglestepmultisizedholepatterningphotolithography AT hyunmyungkim highidenticalnumericalaperturemultifocalmicrolensarraythroughsinglestepmultisizedholepatterningphotolithography AT youngminsong highidenticalnumericalaperturemultifocalmicrolensarraythroughsinglestepmultisizedholepatterningphotolithography |