NANOCOMPOSITE REFRACTIVE INDEX GRADIENT VARIABLE FOCUS OPTIC
A nanocomposite ink refractive gradient optic with variable focus optic comprising a first optical element, a second optical element, each the optical elements comprised of a cured nanocomposite ink wherein the first and second optical element have a cubic volumetric gradient complex optical index such that when arranged in tandem along an optical axis the optical power varies based on linear translation with respect to another.
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The present disclosure relates in general to refractive optics. This application relates in particular to nanocomposite gradient optical index variable focus optics.
DISCUSSION OF BACKGROUND ARTA zoom optic or variable-focus optic has an effective focal length or power that can be manipulated to change magnification. The most prevalent type of zoom lens comprise a grouping of optical elements situated along an optical axis wherein change in effective focal length is accomplished by movement of one or more of the optical elements along the optical axis. Other systems include optical-elements wherein surface curvature or shape can be altered mechanically or by some other stimulus. This disclosure relates to another approach.
SUMMARY OF THE DISCLOSUREThe present disclosure is directed to a nanocomposite refractive gradient variable focus optic. In one aspect the nanocomposite-ink refractive gradient optic with variable focus optic comprising a first optical-element, a second optical-element, each the optical-elements comprised of a cured nanocomposite-ink wherein the first and second optical-element have a cubic volumetric gradient refractive-index such that when arranged in tandem along an optical axis the optical power varies based on linear translation with respect to another.
The accompanying drawings, which are incorporated in and constitute a part of the specification, schematically illustrate preferred embodiments of the present disclosure, and together with the general description given above and the detailed description of preferred methods and embodiment given below, serve to explain principles of the present disclosure.
Referring now to the drawings, wherein like components are designated by like reference numerals. Figures are characterized by mutually perpendicular axis in Cartesian coordinates allow other coordinate systems can be used. Methods of manufacture and various embodiments of the present disclosure are described further hereinbelow.
Referring to
The cubic volumetric gradient refractive-index is achieved by depositing and curing one or more types of the nanocomposite-inks. The optical properties of the organic-matrix, the nanoparticles, and the nanoparticle concentration determine the refractive-index in any particular area. The cured nanocomposite-inks comprising the nanoparticles dispersed within the organic matrix can be composed of various materials. The organic-matrix of the nanocomposite-ink is a curable resin optically transmissive for those wavelengths of the optical-elements intended use. Within the present disclosure, nanocomposite-inks can also include the organic-matrix without nanoparticles, also referred to as neat organic-matrix. The organic-matrix can be cured by photo exposure, thermal processes chemical process, and combinations thereof. Non-limiting examples of organic-matrix materials include polyacrylate, hexanediol diacrylate (HDODA), polymethyl methacrylate (PMMA), diethylene glycol diacrylate (DEGDA), neopentyl glycol diacrylate (NPGDA), tricydodecane dimethanol diacrylate (TCDDMDA), bisphenol A novolcepoxy dissolved in organic solvent (SU-8), and other such materials.
The nanoparticles dispersed within the organic-matrix can be any material or nanostructure that is sufficiently small, for those wavelengths of the optical-element's intended for use, not to scatter light. The nanoparticles can comprise one or more metal, dielectric, semiconductor, or organic materials. Nonlimiting examples of nanoparticles include beryllium oxide (BeO), barium titinate (BaTiO3), aluminum nitride (AlO), silicon carbide (SiC), zinc oxide (ZnO), silicon dioxide (SiO2), hollow silicon dioxide nanospheres (hollow SiO2) zinc sulfide (ZnS), zirconium oxide (ZrO), yttrium orthovanadate (YVO4), titanium oxide (TiO2), copper sulfide (CuS2), cadmium selenide (CdSe), lead sulfide (PbS), tellurium oxide (TeO2), magnesium Oxide (MgO), Aluminum nitride (AlN), LaF3, GaSbO, nano-Diamond, ThF4, HfO2—Y2O3, Yb2O3, Dy2O3, ZrO2—Y2O3, Si3N4, Y2O3, KBr, Ta2O5, HfO2, AlGaP, SiGe, GaAs, Au, LiF, and molybdenum disulfide (MoS2) including those with core, core-shell, core-shell-ligand, and hollow architectures.
The nanocomposite-inks can be formulated by the nanoparticles type or type, the organic-matrix, organic-matrix type, concentration of nanoparticles, and combinations thereof. The refractive-index of the nanocomposite-inks is influenced by the formulation. An approximation of the optical properties can be calculated based on the linear summation of the optical properties calculated for the proportionate volume percentage of the organic-matrix materials and the optical properties calculated for the volume percentage of the nanoparticles, although direct measurement is a preferred method of determining the refractive index for any given nanocomposite-ink formation. For a nanocomposite-ink with one nanoparticle type, the refractive index is given by the following equation:
neff(λ)=V%NP×nNP(λ)+V%ON×nOM(λ),
where neff(λ) is the effective index of the nanocomposite-ink, V%NP is the percent volume of the nanoparticles nNP(λ) is the refractive-index of the nanoparticles, V%OM is the percent volume of the organic-matrix, and nOM(λ) is the refractive-index of the organic-matrix. Additional nanoparticles types can be added and percent volume and refractive-index included in the equation. For instance, nanocomposite-ink with nanoparticles that have a high-index relative to the organic-matrix will have a refractive-index that increases in proportion to the volume of nanoparticles relative to that matrix host material increases. Likewise, a nanocomposite-ink with a low-index nanoparticle, for instance a hollow Buckminsterfullerene or a hollow nanosphere, comprised mostly of air, which has an optical refractive index (n) of n=1, results in a nanocomposite-ink with a refractive index lower than the organic-matrix, which decreases closer to n=1 as the percentage of nanoparticles in the composition increases.
Using one or more of nanocomposite inks, each formulated with different compositions, the deposition of droplets of various nanocomposite-inks, allows solids with volumetrically varying complex dielectric functions to be fabricated, with allows the materials to exhibit first- and higher-order complex optical properties. These properties can include the index of refraction, third-order susceptibility, or other nonlinear optical effects. One method of manufacturing the optical-element of the present disclosure is inkjet printing, described in detail further below.
Inkjet printing the nanocomposite-ink allows materials with complex optical effects to be formed that can vary throughout their volume. These effects include the first order complex refractive index and higher order nonlinear effects such as the real and imaginary parts of the third-order susceptibility and the nonlinear refractive index and absorption coefficients.
To manufacture a volumetric gradient refractive-index at least two of the nanocomposite-inks must be used, although additional optical inks, including optical inks without nanoparticles. These inks can be printed individually, or can be mixed during the printing process to yield optical properties that differ from that of the droplets themselves. One of the nanocomposite-inks printed must have an optical index at least as low as that required by the gradient optical profile and the other nanocomposite-ink must have an optical index as least as high as the highest required by the gradient optical index profile. Intermediate values can be obtained by controlled deposition techniques including nanoparticle diffusion control and advective mixing. Such printing apparatus and printing techniques are described in U.S. patent application Ser. No. 14/863,297, assigned to the assignee of the present invention, and hereby incorporated by reference in its entirety.
One method of manufacturing the nanocomposite-ink gradient complex optical index solid includes the steps of having or providing a nanocomposite-ink printing apparatus with a nanocomposite-ink comprising of an organic-matrix with a nanoparticle dispersed within. Depositing and forming a first optic-element having a first surface and a second surface with a cubic volumetric gradient optical index. Depositing and forming a second optic-element having a first and a second surface with a cubic volumetric gradient refractive-index.
The variable focus optic can be printed separately as shown in
First optical-element 14 and second optical-element 24 have a cubic volumetric gradient refractive-index profile wherein the z-axis integrated nanocomposite-ink profile through both the first optical-element and the second optical element has at least an approximate parabolic refractive-index profile. The parabolic refractive-index profile changes as a function of linear translation between first optic 14 and second optic 24. In some embodiments the parabolic profile has a symmetric change as a function of translation in the x-axis. Such embodiments have a cubic refractive-index profile described by:
∫C(x, y, z)dz=Axx3+Axyyx2+Bx2+Cxy+Dy2+Ex+Fy+G,
where A, B, C, D, E, and F are constants that can be optimized to obtain a desired profile. The cubic concentration profile of the first optical element has a cubic term that is the opposite in sign of the second optical-element such that the cubic term is eliminated in summation of each of the cubic concentration profiles and the summed concentration profile has a parabolic term −2Aδ(x2+y2), where offset δ is the linear offset from the optical-axis of each the optical-element. In other embodiments the parabolic refractive-index profile has a cylindrical power change when translated in the x-axis or the y-axis. Such embodiments have a cubic concentration profile described by:
∫C(x,y,z)dz=N0(1−(Axx3+Ayy3+Bx2+Cxy+Dy2+Ex+Ey)), here
both cubic terms are eliminated in summation. Equal spatial translation in both the x-axis and y-axis causes a symmetric power change.
The focal length of the variable power optic is inversely proportional to the offset and thickness of the optical-elements although the thickness of the optical-elements and spatial separation between the two optical-elements must remain sufficiently thin such that the thin lens approximation remains accurate. For planar optics with approximately the same magnitude coefficients, thickness and offset of zero, the focal length is infinite and therefore the optic has zero power. For a positive offset, the power increases, for a negative offset power decreases.
Referring to
An on-axis ray 57A, a marginal ray 56A, and a marginal ray 58A propagate in parallel to neutrally aligned optical-elements 42 and 44. The rays enter at an orthogonal angle to first surface 50, continuously refract through first optical-element 42 exit second surface 52 into an air gap 54 at an angle oblique with the optical axis. The rays refract at first surface 46 and continuously refract through first optical-element 42 such that the rays exit orthogonal to second surface 48 and parallel to the optical axis.
Referring to
An on-axis ray 57B, a marginal ray 56B, and a marginal ray 58B propagate in parallel to positively aligned optical-elements 42 and 44. As before all the optical rays enter at an orthogonal angle to first surface 50. Here, optical ray 56B refracts little though second optical element 44, exits, then refracts towards the optical-axis through first optical-element 42 towards the larger concentration of nanoparticles, and exits first second surface 48 converging towards a focal spot. On-axis ray 57B continuously refracts through second optical-element 50 in the positive x-direction, refracts through first optical element 52 in the negative x-direction towards the optical axis and exits about parallel with the optical-axis, although some parallax may occur due to the asymmetry. Marginal ray 58B refracts continuously through second optical-element 44 towards the larger concentration of nanoparticles and exits second surface 52 towards first optical element 42. Marginal ray 58B refracts little through first optical element 42 and exits first surface 48 towards the focal spot.
Referring to
An on-axis ray 57C, a marginal ray 56C, and a marginal ray 58C propagate in parallel to positively aligned optical-elements 42 and 44. As before all the optical rays enter at an orthogonal angle to first surface 50. Here, optical ray 56C refracts little though second optical element 44, exits, then refracts away from the optical-axis through first optical-element 42 towards the larger concentration of nanoparticles, here shifted away from the optical axis. Optical ray 56C exits first second surface 48 diverging from the optical-axis. On-axis ray 57C continuously refracts through second optical-element 50 in the positive x-direction, refracts through first optical element 42 in the negative x-direction towards the optical axis and exits about parallel with the optical-axis, although some parallax may occur due to the asymmetry. Marginal ray 58C refracts continuously through second optical-element 44 towards the larger concentration of nanoparticles, here diverging from the optical-axis, and exits second surface 52 towards first optical element 42. Marginal ray 58B refracts little through first optical element 42 and exits first surface 48 diverging from the optical-axis.
Referring to
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The first optical element's cubic volumetric refractive gradients are paired with the second optical element's cubic refractive gradients wherein each pair have an optical power that varies on linear translation. By way of example, an exemplary cubic volumetric refractive gradient 216 and 218 has a power when tandemly arranged such as that shown in
Here, each of the cubic volumetric refractive gradients have a square optical shape to increase the fill factor. In other embodiments the optical aperture can be circular. Carbon, metal, or other opaque inks can be used to separate isolate each of the paired cubic volumetric refractive gradients to reduce or eliminate crosstalk during linear translation. As aforementioned, the area between the first optical-element and second optical element filled and surfaces can shaped.
From the description provided herein one skilled in the art can manufacture the apparatus and practice the methods disclosed in accordance with the present disclosure. In summary, while the present invention has been described in terms of particular embodiments and examples, others can be implemented without departing in scope. The invention is not limited to the embodiments described and depicted herein. Rather, the invention is limited only by the claims appended hereto.
Claims
1-23. (canceled)
24. A method of manufacturing a nanocomposite-ink based optic with a gradient complex optical index and variable focus, the method comprising:
- having or providing a nanocomposite-ink printing apparatus with a nanocomposite ink including an organic matrix with a nanoparticle dispersed within the organic matrix;
- depositing and forming a first optical element having a first surface and a second surface with a gradient optical index;
- depositing and forming a second optic element having a first surface and a second surface with a gradient optical index, the first optical element and the second optical element each comprising a cured nanocomposite ink with an organic matrix and a nanoparticle dispersed within the organic matrix,
- wherein the first and the second optical elements are arranged in tandem along on an optical axis and have an optical power that varies based on translation between the first and second optical element.
25. The method of claim 24 wherein the first optical element and the second optical element are printed in a tandem arrangement.
26. The method of claim 25 further comprising depositing a sacrificial layer between the first optical element and the second optical element, the sacrificial layer facilitating post fabrication physical separation of the first optical element and the second optical element.
27. The method of claim 25 further comprising depositing an elastomeric layer between the first optical element and the second optical element.
28. The method of claim 24 further comprising depositing an alignment feature on the first optical element and/or the second optical element.
29. The method of claim 28 wherein the alignment feature is configured for informing post-process surface figuring.
30. The method of claim 28 wherein the alignment feature is configured as a guide for cleaving, sawing, or otherwise physically separating the first optical element from the second optical element.
31. The method of claim 28 wherein the alignment feature is configured for alignment of the first and second optical elements during assembly of an optical system.
32. The method of claim 24 wherein the first optical element and the second optical element include an array of optical elements, each comprising a cubic refractive gradient profile.
33. The method of claim 32 wherein the array is printed in a square, hexagonal, or other close-packed geometry chosen to limit an amount of light striking a non-index modulated portion of the first or second optical element.
34. The method of claim 24 wherein two or more nanocomposite inks are used to fabricate the optical element.
35. The method of claim 34 wherein the two or more nanocomposite inks are inter-diffused on a substrate to create intermediate refractive index values derived from a proportion of each optical ink.
36. The method of claim 24 wherein the two or more nanocomposite inks are achromatic.
37. The method of claim 24, wherein the translation is a linear translation orthogonal to the optical axis.
38. The method of claim 24, wherein the gradient index profile is a cubic polynomial function.
39. The method of claim 24, wherein the gradient index profile varies in three dimensions.
40. The method of claim 29, wherein the elastomeric layer includes nanoparticles.
41. The method of claim 24, wherein the wherein the cured nanocomposite ink is photo-cured.
42. The method of claim 40, wherein the cured nanocomposite ink is thermally cured.
43. The method of claim 28, wherein the alignment feature is configured to facilitate translation of the first and second optical elements relative to each other.
44. The method of claim 24, wherein a density of deposited droplets, inter-diffused and cured, is used to define the complex optical gradient.
45. The method of claim 44, wherein a volume of each of the deposited droplets is below 10 picoliters.
Type: Application
Filed: Oct 7, 2022
Publication Date: Apr 20, 2023
Applicant: Vadient Optics, LLC (Beaverton, OR)
Inventor: George Williams (Vashon, WA)
Application Number: 18/045,078