Optical devices with embedded organic parts

Abstract

SOLUTION: An optical device can comprise wires 12 on a face of a substrate, with channel(s) 13 between adjacent wires 12. Each wire 12 can include embedded organic moieties. Each wire 12 can include multiple ribs. Part or all of the wire 12, the substrate or both can have a high refractive index n and a low extinction coefficient k.EFFECT: The optical device can reduce separation of layers of different materials during flexing and temperature changes. The optical device can be manufactured by a method designed for improved manufacturability.SELECTED DRAWING: Figure 1a

Description

[Technical field]

[0001] This application relates generally to wire grid polarizers. [Background technology]

[0002] Optical devices can include multiple layers of different materials bonded together. These layers can separate during bending or temperature changes of the optical device due to the different thermal expansion coefficients of the different materials. It would be useful to minimize or eliminate such layer separation.

[0003] Deposition of some optical materials can be difficult and slow, and can introduce additional defects. Some deposition techniques can heat the optical device and adversely affect the grain structure and stoichiometry of the deposited material. Some deposition techniques can introduce undesirable variations in density across a layer. Certain materials can be difficult to etch. It would help improve the manufacturability of optical devices. Summary of the Invention

[0004] It has been recognized that it would be advantageous to minimize or eliminate separation of layers of different materials in optical devices during flexion and during temperature changes. It has been recognized that it would be advantageous to improve the manufacturability of optical devices. The present invention relates to various embodiments of optical devices and methods of making same that meet these needs. Each embodiment may meet one, several, or all of these needs.

[0005] The optical device can include wires on a surface of a substrate having a channel(s) between adjacent wires. Each wire can include an embedded organic moiety. The method can include providing an uncured layer on the substrate and then curing the uncured layer to form a cured layer. The substrate, the wires, the rib(s) in the wires, the cured layer, or a combination thereof can have a refractive index n≧1.7 and an extinction coefficient k≦0.1. [Brief description of the drawings]

[0006] (Drawings may not be drawn to scale.)

[0007] [Figure 1a] 1 is a schematic cross-sectional side view of an optical device 10a including wires 12 on a surface of a substrate 11 with channels 13 between adjacent wires 12, in accordance with one embodiment of the present invention.

[0008] [Figure 1b] FIG. 1 is a schematic cross-sectional side view of an optical device 10b including two wires 12 on a surface of a substrate 11 with a channel 13 between the two wires 12, according to one embodiment of the present invention.

[0009] [Diagram 2] FIG. 1 is a schematic perspective view of an optical device 20 including an array of wires 12 on a surface of a substrate 11, the wires 12 being parallel and elongated, with channels 13 between adjacent wires 12, in accordance with one embodiment of the present invention.

[0010] [Diagram 3] FIG. 1 is a schematic cross-sectional side view of an optical device 30 similar to optical devices 10a, 10b and 20, but in which each wire 12 further comprises two ribs 31, in accordance with one embodiment of the present invention.

[0011] [Figure 4] FIG. 4 is a schematic cross-sectional side view of an optical device 40 similar to optical devices 10a, 10b and 20, but in which each wire 12 further comprises three ribs 31, in accordance with one embodiment of the present invention.

[0012] [Diagram 5] FIG. 1 is a schematic cross-sectional side view illustrating a step 50 in a method of making an optical device, including providing an uncured layer 51 on a substrate 11, in accordance with one embodiment of the present invention.

[0013] [Figure 6]1 shows a schematic cross-sectional side view illustrating a step 60 of a method of making an optical device that may follow step 50, including curing uncured layer 51 to form cured layer 61, in accordance with one embodiment of the present invention.

[0014] [Figure 7] FIG. 1 is a schematic cross-sectional side view illustrating a step 70 in a method of making an optical device, which may follow step 60, including sputter deposition of a thin film 71 onto a stiffening layer 61, in accordance with one embodiment of the present invention.

[0015] DEFINITIONS. The following definitions, including the plural equivalents, apply throughout this patent application.

[0016] As used herein, the term "on" means disposed directly on or above some other solid material.

[0017] As used herein, the term “elongated” means that the length L of the wire 12 is greater than or equal to the wire width W or wire thickness Th. 12 For example, L is the sum of the wire width W and wire thickness Th 12 , or both may be 10 times or more, 100 times or more, 1000 times or more, or 10,000 times or more greater. See FIG. 2.

[0018] As used herein, the term "parallel" means exactly parallel, parallel within standard manufacturing tolerances, or nearly parallel, whereby deviations from exactly parallel will have a negligible effect on normal use of the device.

[0019] As used herein, the term "made of" means that a material has a particular material composition, excluding unintentional impurities.

[0020] The metal oxides listed herein include combinations of metal and oxygen in any ratio, including non-stoichiometric combinations.

[0021] As used herein, the term "substrate" refers to a base material, such as a glass wafer. Unless otherwise specified in the claims, the term "substrate" also includes any thin film(s) sandwiched between the glass wafer and the wires of the polarizer. The substrate can be thick in the optical sense, meaning substantially thicker than the maximum wavelength of light in the wavelength range of use. For example, the thickness of the substrate Th 11 can be 0.1 mm or more, 0.35 mm or more, or 0.6 mm or more.

[0022] Materials used in optical constructions can absorb some light, reflect some light, and transmit some light. The following definitions distinguish between materials that are primarily absorptive, primarily reflective, or primarily transmissive. Each material can be considered to be absorptive, reflective, or transmissive in the wavelength range of its intended use, across the ultraviolet spectrum, across the visible spectrum, across the infrared spectrum, or a combination thereof, and can have different properties in different wavelength ranges. Materials are classified as absorptive, reflective, and transmissive based on the reflectance R, the real part of the refractive index n, and the imaginary part of the refractive index / extinction coefficient k. Equation 1 is used to determine the reflectance R of an interface between air and a uniform slab of material at normal incidence:

number

[0023] Unless otherwise expressly specified in this specification, materials with k≦0.1 within a wavelength range are "transparent" materials, materials with k>0.1 and R≦0.6 within a particular wavelength range are "absorptive" materials, and materials with k>0.1 and R>0.6 within a particular wavelength range are "reflective" materials. If expressly stated in the claims, materials with k>0.1 and R≧0.7, R≧0.8, or R≧0.9 within a particular wavelength range are "reflective" materials.

[0024] As used herein, ultraviolet spectrum means from 10 nm to less than 400 nm, visible spectrum means from 400 nm to less than 700 nm, and infrared spectrum means from 700 nm to less than 1 mm.

[0025] Unless otherwise expressly noted herein, all temperature dependent values ​​are such values ​​at 25°C. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] As illustrated in Figures 1a and 1b, optical devices 10a and 10b are shown comprising wires 12 on a surface of a substrate 11 with a channel(s) 13 between adjacent wires 12. The channels can be filled with air, another gas, vacuum, liquid, solid material, or a combination thereof. The wires 12 can extend in multiple directions and have multiple thicknesses Th, such as in a metamaterial polarizer. 12 Alternatively, the wires 12 can be parallel and elongated, as illustrated in optical device 20 of FIG.

[0027] Each of the optical devices 10a, 10b, and 20 can be a wire grid polarizer (WGP), a waveguide, or other optical device. The optical devices 10a and 20 can include more wires 12 and channels 13 than illustrated. Alternatively, the optical device 10b can include only two wires 12 with a single channel 13 between them. The optical device 10b can be a waveguide.

[0028] Each wire 12 can include reflective ribs, transmissive ribs, absorptive ribs, or combinations thereof, in any order. As illustrated in optical device 30 of FIG. 3, each wire 12 can include two ribs 31. As illustrated in optical device 40 of FIG. 4, each wire 12 can include three ribs 31. Each rib 31 can be of a different material than the other rib(s) in the same wire 12. Each array A of ribs 31 in a single plane parallel to the surface of the substrate can be of a single material. Each array A of ribs 31 can be reflective ribs, transmissive ribs, or absorptive ribs.

[0029] Below are example values ​​of the real part of the refractive index n and the extinction coefficient k for some of the optical devices 10, 20, 30 and 40. The n and k values ​​herein can be across the ultraviolet spectrum, across the visible spectrum, across the infrared spectrum, or combinations thereof.

[0030] The substrate 11 has a relatively low refractive index, real part n S or a higher n depending on the type of optical device 10 or 20. S The substrate 11 can have a low absorption coefficient k S The substrate 11 can be made of or can include an oxide of hafnium, lead, niobium, tantalum, titanium, tungsten, zirconium, or a combination thereof. For example, the substrate 11 can have a n S ≧1.3, n S ≧1.7, n S ≧1.8, n S≧1.9, n S ≧2.0, or n S ≧2.2, n S ≦1.5, n S ≦2.0, or n S ≦3.0, k S ≦0.0001, k S ≦0.001, k S ≦0.01, or k S ≦0.1, or a combination thereof.

[0031] In one embodiment, each wire 12 can be transparent. W ≧1.3, n W ≧1.7, n W ≧1.8, n W ≧1.9, n W ≧2.0, or n W ≧2.2, n W ≦1.5, n W ≦2.0, or n W ≦3.0, k W ≦0.0001, k W ≦0.001, k W ≦0.01, or k W n ≦0.1, or a combination thereof. W is the real part of the refractive index of the wire 12, and k W is the extinction coefficient.

[0032] In one embodiment, the permeable ribs include n T ≧1.3, n T ≧1.7, n T ≧1.8, n T ≧1.9, n T ≧2.0, or n T ≧2.2, n T ≦1.5, n T ≦2.0, or n T ≦3.0, k T ≦0.0001, k T ≦0.001, k T ≦0.01, or k T n can be ≦0.1, or a combination thereof. T is the real part of the refractive index of the transparent rib, and kT is the extinction coefficient. Exemplary materials for the transmissive ribs include hafnium, lead, niobium, tantalum, titanium, tungsten, zirconium, or combinations thereof. The transmissive ribs can include oxides of hafnium, lead, niobium, tantalum, titanium, tungsten, zirconium, or combinations thereof.

[0033] Each wire 12 can include an embedded organic moiety. The reflective ribs, the transmissive ribs, the absorptive ribs, or a combination thereof can include an embedded organic moiety. The inclusion of an organic moiety can improve the flexibility of the optical device. Such flexibility can be useful if the final device needs to be bent over another device, such as a lens. Such flexibility can be useful for layers of the optical device that maintain contact during thermal expansion. This flexibility can even result in different materials maintaining contact despite relatively large differences in thermal expansion coefficients.

[0034] For example, 0.01% or more, 0.1% or more, 1% or more, 10% or more, or 25% or more of the atoms can be part of the organic portion of the wires 12, the reflective ribs, the transmissive ribs, the absorptive ribs, or combinations thereof. For example, 75% or less, 50% or less, 25% or less, 10% or less, or 5% or less of the atoms can be part of the organic portion of the wires 12, the reflective ribs, the transmissive ribs, the absorptive ribs, or combinations thereof. The remainder of each such rib can be inorganic.

[0035] For example, the weight percent of the organic portion of the wires 12, the reflective ribs, the transmissive ribs, the absorptive ribs, or combinations thereof can be 0.01% or more, 0.1% or more, 1% or more, 10% or more, or 25% or more, and 75% or less, 50% or less, 25% or less, 10% or less, or 5% or less. The remainder of each such rib can be inorganic.

[0036] It can be useful for the organic moieties to be small in order to avoid adverse effects on optical properties, balance flexibility and hardness, achieve desired density, and facilitate deposition. For example, each organic moiety can include or be -CH3, -CH2CH3, -CH2CH2CH3, or combinations thereof. As another example, the total organic moiety can include 1 carbon atom, 2 or less carbon atoms, 3 or less carbon atoms, 5 or less carbon atoms, or 10 or less carbon atoms. As another example, the total organic moiety can have a molecular weight of 14 grams / mole or more, 25 grams / mole or more, or 50 grams / mole or more, and 16 grams / mole or less, 30 grams / mole or less, 45 grams / mole or less, 100 grams / mole or less.

[0037] Method. A method for making an optical device may include providing an uncured layer 51 on a substrate 11 (see step 50 in FIG. 5) and curing the uncured layer 51 to form a cured layer 61 (see step 60 in FIG. 6). These steps 50 and 60 may be performed in this order or simultaneously. The optical device and the components of the optical device itself may have properties as described above. Steps 50 and 60 may be repeated for multiple layers. Each repetition of steps 50 and 60 may be performed with a different material. Each cured layer 61 may be reflective, transmissive, or absorptive across the ultraviolet spectrum, across the visible spectrum, across the infrared spectrum, or combinations thereof. The method may further include etching the cured layer(s) to form wires 12, thereby making the optical device 10, 20, 30, or 40.

[0038] Each stiffening layer 61 independently has n C ≧1.3, n C ≧1.7, n C ≧1.8, n C ≧1.9, n C ≧2.0, or n C ≧2.2, n C ≦1.5, n C ≦2.0, or n C≦3.0, k C ≦0.0001, k C ≦0.001, k C ≦0.01, or k C n ≦0.1, or a combination thereof. C is the real part of the refractive index of the cured layer 61, and k C is the extinction coefficient. The curable layer 61 may have embedded organic moieties in proportions as described above. The substrate 11 may have n S and k S may have the following structure:

[0039] In one embodiment, the uncured layer 51 can be a liquid having solid inorganic nanoparticles dispersed throughout a continuous phase. Curing or chemically reacting therein can include forming the uncured layer 51 into a solid interconnected network of inorganic nanoparticles that defines the cured layer 61. In another embodiment, the uncured layer 51 can be a colloidal suspension including a dispersed phase and a continuous phase. Curing or chemically reacting therein can include removing the continuous phase to form a solid that defines the cured layer 61. The solid can be inorganic. The inorganic nanoparticles, the dispersed phase, or both can include metal atoms bonded to organic moieties. In one aspect, each metal atom can be bonded to one or less organic moieties. Examples of organic moieties include -CH3 and -CH2CH3. As a result, the cured layer 61 can include embedded organic moieties. These embedded organic moieties can be useful for changing the properties of the cured layer 61, such as changing its optical properties and hardness.

[0040] In another embodiment, the uncured layer 51 can be a solution containing molecules in a solvent, and the cured layer 61 can be formed by reacting the molecules to form a solid of metal atoms linked together. Solvents can include water and organic liquids. The molecules can include reactive groups R 1Examples of metal atoms include hafnium, lead, niobium, tantalum, titanium, tungsten, and zirconium. Each metal atom can include one or more bonds to a reactive group and one or more bonds directly to an organic moiety.

[0041] Each reactive group R 1 are independently -Cl, -OR 2 ,-OCOR 2 , or -N(R 2 )2. Each R 2 can be independently -CH3, -CH2CH3, -CH2CH2CH3, or an alkyl group. The alkyl group can have at least one carbon atom, but can be small, such as no more than 2 carbon atoms, no more than 3 carbon atoms, no more than 5 carbon atoms, or no more than 10 carbon atoms.

[0042] Each metal atom has one or more bonds to a reactive group or two or more bonds and an organic moiety R 3 Examples of organic moieties include -CH3, -CH2CH3, and -CH2CH2CH3. Examples of molecules include (R 3 )Hf(R 1 )3,(R 3 )Pb(R 1 ),(R 3 )Nb(R 1 )4,(R 3 )Ta(R 1 )4,(R 3 )Ti(R 1 )3,(R 3 )W(R 1 )5,(R 3 )Zr(R 1 )3.

[0043] The forming of the uncured layer 51 into the cured layer 61 can include evaporating at least some of the liquid, and such evaporation can be combined with the curing step described above. In one embodiment, all of the liquid initially in the uncured layer 51 is either reacted to form a solid (the cured layer 61) or evaporated. The forming of the uncured layer 51 into the cured layer 61 can include the use of ultraviolet light, heat, or both. The integrity of the cured layer 61 can be determined, for example, over a period of 30 minutes. o C or higher, 50 o C or above, or 100 o C or above, and 150 o Below C, 200 o Below C, 250 o C or below, or 300 o This can be improved by curing at relatively low temperatures such as

[0044] As illustrated in FIG. 7, the method described above can further comprise sputter deposition of a thin film 71 onto the stiffening layer 61. The thin film 375 can be any material having the desired optical properties, polarizer protection properties, or both. The thin film 71 can be etched with the stiffening layer 61 and can become the ribs 31 in the final wire 12, can be used as an etch mask, or both. The thin film 71 can be reflective, absorptive, or transmissive across the ultraviolet spectrum, across the visible spectrum, across the infrared spectrum, or combinations thereof, as specified in the claims. Sputter deposition of the thin film 71 can reduce voids in the stiffening layer 61.

[0045] The steps of spin coating, then baking, spin coating, then baking again, and possibly repeated many more times to form the uncured layer 51 can improve the uniformity of the final cured layer 61. The time for each spin coat depends on the desired thickness and the spin coater. Exemplary times include 2 seconds or more, 4 seconds or more, or 6 seconds or more, and 10 seconds or less, 20 seconds or less, or 30 seconds or less for each spin coat. Exemplary speeds for each spin coat include 100 rpm or more, 500 rpm or more, 1000 rpm or more, 1500 rpm or more, and 2500 rpm or less, 3000 rpm or less, 4000 rpm or less, or 8000 rpm or less. Exemplary temperatures for each bake include 30 o C or higher, 50 o C or higher, 100 o C or above, or 150 o C or above, and 250 o Below C, 300 o C or below, or 400 o Includes C and below.

[0046] Thickness Th of uncured layer 51 51 , Th thickness of hardened layer 61 61 , and the thickness Th of the thin film 71 71 Examples of such a thickness Th include 10 nm or more, 50 nm or more, 100 nm or more, 200 nm or more, and 300 nm or less, 600 nm or less, or 1000 nm or less. 51 , Th 61 , and Th 71 can be the maximum, minimum, or average of the layer.

[0047] Some materials, such as titanium oxide, can be very difficult to etch. Titanium oxide formed by the above-mentioned method can be easy to etch, thus improving the manufacturability of optical devices. Sputter deposition can be difficult and slow, and can heat up the optical device, which can adversely affect the grain structure and stoichiometry of the deposited material, resulting in undesirable variations in the overall density of the deposited layer. In contrast, the above-mentioned method can be performed more quickly, at relatively low temperatures, with reduced density variations.

Claims

1. A wire grid polarizer (WGP), comprising: wires on a surface of a substrate having channels between adjacent wires; Each wire includes a reflective rib, a transmissive rib, and an absorptive rib; The transparent rib has a refractive index of less than or equal to the real part n across the ultraviolet spectrum, across the visible spectrum, across the infrared spectrum, or a combination thereof. Ｔ ≧1.7 and extinction coefficient k T ≦0.1, The atoms of the permeable rib are included in the organic moiety in an amount of 0.1% or more and 50% or less of the substance of the permeable rib, and the atoms of the permeable rib are included in the organic moiety in an amount of 0.1% or more and 50% or less of the substance of the absorbent rib, and the organic moiety is a moiety containing an organic functional group bonded to a metal atom. WGP.

2. The WGP of claim 1 , wherein the permeable rib comprises an oxide of hafnium, lead, niobium, tantalum, titanium, tungsten, zirconium, or combinations thereof.

3. Across the visible spectrum Ｔ 3. The WGP of claim 1 or 2, which is > 2.

0.

4. 4. The WGP of claim 1, wherein the weight percentage of the organic moiety in the permeable rib is greater than or equal to 0.1% and less than or equal to 20%.

5. The organic moiety is —CH ３ , -CH ２ CH ３ 5. The WGP of claim 1 , comprising:

6. 6. The WGP of claim 1 , wherein all organic moieties contain 3 or less carbon atoms.

7. 7. The WGP of claim 1, wherein greater than or equal to 1% and less than or equal to 25% of the atoms in the permeable rib are in organic moieties.

8. 8. The WGP of claim 1, wherein greater than or equal to 0.1% and less than or equal to 50% of the atoms in the reflective rib are in organic moieties.

9. The substrate may have a refractive index of less than or equal to the real part n across the ultraviolet spectrum, across the visible spectrum, across the infrared spectrum, or a combination thereof. ｓ ≧1.7 and extinction coefficient k Ｓ 9. The WGP of claim 1 having a .DELTA..times ...

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