We propose to develop 3D printing technology of glass micro-objective and micro optics for ultrathin endoscope
to address the increasing demand in developing compact endoscopes in cancer imaging. The primary challenge
in developing micro-objective is the fabrication, traditional fabrication methods don’t have sufficient capabilities
in fabricating micro optics. GRIN lens is the only commercially available micro-objective, but it has a number of
limitations, such as narrow working spectrum and very short working distance. 3D printing process has been
developed recently to print polymer micro-objective with two-photon polymerization (TPP) process. However,
there are some inherent limitations in printed polymer optics, including short lifetime due to the yellowish, low
transmission in UV and NIR spectrum, and limitations in hardness, thermal resistance, and chemical resistance.
Glass optics is preferred for clinical application because of its excellent optical, chemical, and thermal properties.
To meet the increasing needs of high-precision glass micro-optics for endoscope and address the major
limitations of current 3D printing optics, we have developed a solvent-free, pre-condensed liquid silica resin (LSR)
and two-photon 3D printing process for glass optics. 3D printing of glass micro-optics with isotropic shrinkage,
micrometer resolution, low deviation peak-to-valley value (<100 nm), and low surface roughness (< 6 nm) has
been achieved. The solvent-free, UV curable LSR with a majority of the already formed covalent bonds
(Si-O-Si) is novel that it significantly reduces the material shrinkage, increases the printing speed, and simplifies
the process to obtain inorganic silica. The printed glass micro optics has better imaging performance with
higher resolution, wider working spectrum, better transmission from UV to NIR, and longer lifetime. The 3D
printing process for micro glass objective is novel in that it can fabricate more complex optical systems and
is particularly suitable for rapid prototyping at low-cost.
The goal of this project is to develop 3D printed glass micro-objective and micro optics for ultra-compact
endoscope. We will first optimize pre-condensed LSR (Aim 1), and then print micro-objectives and evaluate the
performance (Aim 2).
This project is significant in that it will establish a new 3D printing technology for fabricating the much-needed
glass micro-objective and micro-optics for endoscope in cancer imaging. The rapid prototyping capability at low
cost will accelerate the rapid transition of the advanced imaging technologies from the lab to clinical applications.