TWI624695B - Flexible Liquid Crystal Lens Array - Google Patents

Abstract

A flexible liquid crystal lens array is applicable to a near-eye display, comprising two flexible substrates, a first soft transparent electrode layer, a soft liquid crystal layer, and a second soft transparent electrode layer, wherein the soft liquid crystal layer is disposed between the two soft transparent electrode layers And having a soft interstitial layer to accommodate the liquid crystal, and the two soft transparent electrode layers are composed of soft nanowires to provide better electrode flexibility and ensure conductivity during flexing. Converting a conventional rigid liquid crystal lens array into a soft array increases the field of view and improves immersion and reduces optical correction.

Description

Soft liquid crystal lens array

The invention relates to a liquid crystal lens array, which is applied to near-eye display and naked-eye 3D stereoscopic display, in particular to a soft liquid crystal lens which can increase the field of view of the near-eye display, solve the problem of focus and parallax conflict, and reduce the discomfort of viewing the near-eye display. Array.

In recent years, people's demand and dependence on digital information has become higher and higher. In order to facilitate access to information anytime and anywhere, near-eye displays have become the focus of research in the display field, and near-eye displays can be widely used in Augmented Reality and virtual. Virtual Reality and Mixed Reality.

Generally, the near-eye display can be divided into a single-eye type and a double-eye type. In the case of a two-eye type near-eye display, different images are received by both eyes, and the distance of the displayed object is discriminated by the parallax of the binocular image, but the object actually The imaging is focused at different distances, so there is an accommodation-convergence conflict, which tends to make people feel dizzy and the like.

In order to solve the conflict between focus and parallax, Integral Imaging or Light Field Display is applied to near-eye displays. Integral imaging and light field display use lens arrays to reproduce the light field of 3D objects, which can be set to image. At different depths, it can force the human eye to change the focus distance to be equal to the distance of the object perceived by the binocular parallax, thus solving the problem of focus and parallax conflict, reducing the discomfort of viewing the near-eye display, and improving viewing comfort. A near-eye display using integrated imaging and light field display technology may be referred to as a light field near-eye display.

On the other hand, in order to make the integral imaging have the best imaging quality on each imaging surface, the variable focal length liquid crystal lens array is proposed to be applied to the light field type near-eye display, and different focal lengths correspond to imaging ranges of different depths. In order to increase the field of view and wrap of the near-eye display, a soft display is proposed for use in a near-eye display. However, for a near-eye display of a light field type, in addition to a display requiring softness, a flexible liquid crystal lens array is required as Collocation, but the existing liquid crystal lens arrays are rigid lens arrays, and the liquid crystal lens array cannot be bent, and cannot be applied to a light field type near-eye display.

Therefore, how to provide a flexible liquid crystal lens array, which can be applied to a light field type near-eye display, is an urgent problem to be overcome.

In view of this, the main object of the present invention is to provide a flexible liquid crystal lens array, which substantially solves the defects of the prior art, can not only bend, and can be applied to a naked-eye stereoscopic display and a near-eye display, thereby greatly increasing the field of view and improving. Immersive and reduce optical correction.

In order to achieve the above object, the present invention provides a flexible liquid crystal lens array comprising two flexible substrates, a first soft transparent electrode layer, a soft liquid crystal layer, and a second soft transparent electrode layer, and the soft liquid crystal layer is disposed on the two soft transparent electrode layers. And have a soft interstitial layer to accommodate the liquid crystal, and then collectively disposed on the flexible substrate; and the two soft transparent electrode layers have soft nanowires to constitute the electrode to provide better electrode flexibility and ensure deflection Conductivity at the time, and at least one of the first flexible transparent electrode layer or the second flexible transparent electrode layer comprises a patterned soft nanowire, and a gradient distribution of the electric field can be formed to control the liquid crystal deflection to produce a lens effect.

Furthermore, the soft interstitial layer is used on the one hand as a cavity for accommodating the liquid crystal, and more importantly, as a support for the overall structure during the bending of the entire liquid crystal lens array, because of the soft interstitial layer and the upper and lower structures In the blocking relationship, during the bending of the liquid crystal lens array, the bending is restricted by the adhesion relationship so that the distance between the two flexible substrates remains the same, and the stretching caused by the bending is prevented, so that the distances in the two flexible substrates are different. The collapse or deformation of the internal structure is ensured, and the normal working environment of the internal liquid crystal structure during the bending process is ensured.

The purpose, technical content, features and effects achieved by the present invention will be more readily understood by the detailed description of the embodiments.

1 is a cross-sectional view showing a first embodiment of a flexible liquid crystal lens array according to an embodiment of the present invention. The flexible liquid crystal lens array includes a first flexible substrate 11, a first flexible transparent electrode layer 20, a flexible liquid crystal layer 30, a second flexible transparent electrode layer 40, and a second flexible substrate 12, and the first flexible transparent electrode layer 20 is disposed on The first flexible substrate 11 is formed of a soft nano-metal wire, and the flexible liquid crystal layer 30 is interposed between the first flexible transparent electrode layer 20 and the second soft transparent electrode layer 40, and is internally provided for the liquid crystal 34. To accommodate, the second flexible transparent electrode layer 40 is also composed of a soft nanowire; in other words, the entire liquid crystal lens array is bonded by a soft material to bend the entire structure, and at least one of the first The flexible transparent electrode layer 20 or the second soft transparent electrode layer 40 includes a patterned soft nanowire, and is capable of forming a gradient distribution of a gradual electric field, controlling liquid crystal deflection, and producing a lens effect.

The first flexible transparent electrode layer 20 and the second flexible transparent electrode layer 40 are respectively disposed on the first flexible substrate 11 and the second flexible substrate 12 by using the nano metal wires, and the first flexible substrate 11 and the second flexible substrate 12 are both For the transparent substrate, the material is selected from the group consisting of glass, polyimide, polymethyl methacrylate, polycarbonate, polyethylene naphthalate, polyethylene terephthalate, polyolefin, fluorine Polymer, polyamide, organic oxime resin, polyether ketone, polyether ketone ketone, polynorbornene, polyester, polystyrene, cellulose triacetate and combinations thereof, these materials can be used as a substrate material to ensure The requirement of light transmission, on the other hand, can also achieve a soft effect, which not only ensures the softness requirement, but also effectively fixes the nanowire. The material of the nanowire is selected from the group consisting of silver, gold, iron, nickel, titanium and combinations thereof to provide an effective guarantee of the conductive effect, and the first soft transparent electrode layer 20 and the second layer can be formed by, for example, coating. Soft transparent electrode layer 40.

In addition, the first soft transparent electrode layer 20 and the second soft transparent electrode layer 40 may further comprise a matrix, and the matrix is a gel-like substance, and there are mainly three kinds of functions: on the one hand, as a viscosity modifier, improving the first and the coating process. The film-forming property of the coating dispersion of the second soft transparent electrode layers 20, 40; on the one hand, it can be bonded on a transparent substrate, and the nanowires are bonded and arranged on the transparent substrate, not only fixing the nanowire, but also The contact between the nanowires is tighter, the contact resistance between the nanowires is lowered, and the electrical conductivity is improved. On the other hand, during the whole bending process, the matrix is deformed along with the whole, thereby ensuring the nanometal. The relative position of the wire does not change during the bending process, and the conductive stability is improved; the material is selected from the group consisting of polyurethane, acrylate resin, fluorenone, polydecane, polyvinyl chloride, polystyrene, epoxy resin, fluorine. Polymer, polyamide, polyimide, polynorbornene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, modified starch, modified cellulose, chitosan, starch, fiber , vegetable gum, polyacrylamide, polyvinylpyrrolidone and combinations thereof to provide better protection and adhesion.

The patterning treatment of the soft nanowires is an orientation patterning process, and the orientation patterning is performed on the electrodes formed by the soft nanowires, and the nanowires tend not to be arranged in the patterned pattern position. , a non-conducting region is formed; the nanowires tend to be arranged in a region between the patterning patterns to form a conductive region. The spacing between the patterns is controlled between one-half and one-third of the length of the nanowire, and the nanowires are arranged in a smaller space to form an orientation effect, the same number of nemesis The rice metal wire can generate more effective conductive paths, that is, the conductive effect under the same conditions is required, and less nano metal wires can be used to improve the light transmittance of the soft nano electrode. The patterned processing pattern may be one or more of a triangle, a rectangle, a hexagon, or a circle.

The flexible liquid crystal layer 30 includes two alignment layers 31 and 32 and a soft spacer layer 33 sandwiched between the two alignment layers 31 and 32. The soft spacer layer 33 includes a plurality of soft spacers to form a space for accommodating the liquid crystal 34. Therefore, the soft spacer layer 33 serves as a cavity for accommodating the liquid crystal 34 on the one hand, and as a support structure of the overall structure during the bending of the entire liquid crystal lens array on the other hand, because the soft spacer layer 33 and the upper and lower structures There is a blocking relationship between the liquid crystal lens arrays. Therefore, the bending is restricted by the adhesion relationship so that the distance between the upper and lower layers remains the same, and the stretching caused by the bending is prevented from being inconsistent, resulting in internal structures. The collapse or deformation, that is, to ensure the normal working environment of the internal liquid crystal structure during the bending process. The liquid crystal is selected from the group consisting of a blue phase liquid crystal, a polymer liquid crystal, a cholesteric liquid crystal, a photoactive reactive liquid crystal, and combinations thereof.

The soft spacers in the soft spacer layer 33 may have several different aspects, for example, they may be soft micro-pillars, which may be disposed at the center or non-pattern area of the pattern corresponding to the patterning process of the soft nanowire electrode. The width is less than or equal to 100 um. The microcolumns are used as soft spacers, and the space between the micropillars and the upper and lower structures forms a space for accommodating the liquid crystals 34, and the microcolumns and the upper and lower structures are adhered to each other, and the internal structure can be bent while ensuring the same internal spacing, that is, the interior The structure is not damaged by the overall bending.

In addition, the soft spacers may also be polymer walls, and the walls of the polymer walls are connected to each other to form a plurality of hollow structures inside, and the liquid crystals 34 are disposed in the hollow interior, because the hollow structures are relatively independent. The utility model can reduce the flow effect of the liquid crystal 34 during normal operation, enhance the overall imaging effect, and adopt a structure in which the cavities are connected to each other, thereby providing a more stable pillar structure during the bending process to ensure the stability of the internal space. The material of the polymer wall is selected from the group consisting of diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, ethoxy Base bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, urethane diacrylate, β hydroxyethyl methacrylate, methyl acrylate, isobornyl methacrylate, acrylic acid Isobornyl ester, ethyl methacrylate, 2-(2-ethoxyethoxy)ethyl acrylate, acrylic acid-3,5,5-trimethylhexyl ester, and combinations thereof.

On the other hand, the soft spacer can also be in the form of a soft micro-cover, the liquid crystal 34 is accommodated in the cover, so that the liquid crystal 34 is not easy to flow freely during operation, and the micro-cover structure can be used to reduce the process steps of the liquid crystal 34 package. The shape may be various types of polygons, and since the shapes may be different, the shape of the micro-mask cover may be randomly arranged, and by randomly arranging the positions of the shape of the cover, it is possible to reduce the occurrence of moire by regular arrangement. Moreover, the cover walls of the soft micro-covers are connected to each other, and the cover bottoms are also connected to each other, which can provide a more stable support during the whole bending process, and ensure the internal space size is unchanged.

In the present embodiment, the second flexible transparent electrode layer 40 includes a patterned soft nano-metal wire, and the second flexible transparent electrode layer 40 and the soft liquid crystal layer 30 further include a soft high-resistance film layer 41. The electric field can be made to distribute the electric field to the center of the pattern area using less electric power, and the conventional method is to increase the voltage, which makes the driving efficiency low, and the energy use effect is poor; at the same time, the soft high-resistance film layer 41 is added to make the electric field voltage The curve is smoother, which is good for the liquid crystal lens to work at high quality. The material of the soft high-resistance film layer 41 is selected from the group consisting of ruthenium oxide, ruthenium nitride, ruthenium carbide, aluminum oxide, transparent polymer material, and combinations thereof. The second flexible transparent electrode layer 40 is disposed under the second flexible substrate 12, thereby providing surface support and protection by the upper and lower flexible substrates 11, 12.

In practice, a square wave of 1 kHz and 2 V _rms can be applied, and the patterned soft nanowire electrode can produce a gradual electric field distribution, and the liquid crystal 34 molecules in the soft liquid crystal layer 30 are turned and distributed along the electric field direction, and have a lens effect. The soft high-resistance film layer 41 enables the electric field to be distributed in the patterned electrode region, and the two flexible substrates 11, 12 and the soft liquid crystal layer 30 are equivalent to the capacitor structure. By simultaneously adjusting the potential difference and frequency of the two electrodes, the shape of the liquid crystal lens, that is, the curvature of the liquid crystal lens or the ability to deflect the light, and gradually increasing the voltage and frequency applied by the upper and lower voltages can increase the diopter of the liquid crystal lens.

2 is a cross-sectional view showing a second embodiment of a flexible liquid crystal lens array according to an embodiment of the present invention. The structure is substantially the same as that of the first embodiment described above, except that the second flexible substrate 12 is disposed between the second flexible transparent electrode layer 40 and the flexible liquid crystal layer 30, and the uppermost portion is provided with the transparent protective layer 43; The same part will not be described again. In practice, a square wave of 1 kHz and 5 V _rms can be applied, and the patterned soft nanowire electrode can generate a gradual electric field distribution, and the liquid crystal 34 molecules in the soft liquid crystal layer 30 are turned and distributed along the electric field direction, and have a lens effect. . Adjusting the voltage applied by the upper and lower voltages can change the curvature of the liquid crystal lens.

FIG. 3 is a cross-sectional view showing a third embodiment of a flexible liquid crystal lens array according to an embodiment of the present invention. The structure is substantially the same as that of the first embodiment. The second flexible transparent electrode layer 40 includes a flexible liquid crystal control electrode layer 401 and a soft gate control electrode layer 402 which are sequentially disposed on the flexible liquid crystal layer 30. The electrode layer 401 includes a transparent semiconductor layer 411 and an edge control electrode 412 and a central control electrode 413 distributed thereon, and the soft gate control electrode layer 402 includes a transparent insulating layer 421 and a gate control electrode distributed thereon. 422 and compensation capacitor electrode 423. The gate control electrode 422 is extended to the outside of the array or the edge of the substrate to be connected to the driving circuit, so that the driving circuit can apply a voltage to the gate control electrode 422, and the equivalent conductivity of the underlying transparent semiconductor layer 411 can be controlled. In turn, the amount of current flowing through the gate control electrode 422 can be controlled. The edge control electrode 412 also extends outside the array or the edge of the substrate to be connected to the driving circuit. The central control electrode 413 is floating, is not linked to any driving circuit, and is connected between the edge control electrode 412 and the central control electrode 413. The transparent semiconductor layer 411 is used to raise the equivalent conductivity of the transparent semiconductor layer 411 between the electrodes by the gate control electrode 422.

The edge control electrode 412 can quickly charge and discharge the central control electrodes 413. The charging or discharging is determined by the relative height of the edge control electrode 412 and the central control electrode 413. Finally, the edge control electrode 412 and the central control electrode 413 reach an equipotential. . At this time, the equivalent conductivity of the transparent semiconductor layer 411 between the two electrodes is further lowered by the gate control electrode 422, so that the potential of the central control electrode 413 is not easily affected by the potential of the edge control electrodes 412 on both sides, and the potential of the central control electrode 413 can be made. Saved. The potential of the central control electrode 413 and the potential of the edge control electrode 412 affect the liquid crystal 34 molecular steering distribution of the lower soft liquid crystal layer 30, and affect the effect of the lower soft liquid crystal layer 30 forming a lens; when the central control electrode 413 potential and the edge control electrode 412 When the potentials are equal, the liquid crystal molecules of the soft liquid crystal layer 30 have a lens-free distribution, and when the potential of the central control electrode 413 and the edge control electrode 412 have a potential difference, the liquid crystal molecules of the soft liquid crystal layer 30 have a lens effect, and the potential difference between the two electrodes It will affect the shape of the liquid crystal lens, that is, the curvature of the liquid crystal lens or the ability to deflect light. Therefore, the liquid crystal lens unit is locally controlled, thereby being applicable to a near-eye display device such as Augmented Reality, Virtual Reality, and Mixed Reality.

Therefore, by using the flexible liquid crystal lens array disclosed in the present invention, a conventional rigid liquid crystal lens array is converted into a flexible liquid crystal lens array, which can be bent to be applied to a naked-eye stereoscopic display and a near-eye display to increase the field of view and enhance immersion. Sense, reduce optical correction. And by supporting the overall structure of the soft spacer, the internal structure is protected from being affected during the bending process, and a stable internal space structure is provided; at the same time, the soft nanowire is used to form the electrode, which can be bent in the whole device. The conductivity is ensured in the case of overcoming the inflexibility of the conventional rigid array.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Therefore, any changes or modifications of the features and spirits of the present invention should be included in the scope of the present invention.

11‧‧‧First flexible substrate

12‧‧‧Second flexible substrate

20‧‧‧First soft transparent electrode layer

30‧‧‧Soft liquid crystal layer

31‧‧‧Alignment layer

32‧‧‧Alignment layer

33‧‧‧Soft interstitial layer

34‧‧‧LCD

40‧‧‧Second soft transparent electrode layer

41‧‧‧Soft high-resistance film

43‧‧‧Transparent protective layer

401‧‧‧Soft liquid crystal control electrode layer

402‧‧‧Soft gate control electrode layer

411‧‧‧Transparent semiconductor layer

412‧‧‧Edge control electrode

413‧‧‧Central control electrode

421‧‧‧Transparent insulation

422‧‧‧ gate control electrode

423‧‧‧Compensated Capacitor Electrode

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing a first embodiment of a flexible liquid crystal lens array according to an embodiment of the present invention. 2 is a cross-sectional view showing a second embodiment of a flexible liquid crystal lens array according to an embodiment of the present invention. Figure 3 is a cross-sectional view showing a third embodiment of a flexible liquid crystal lens array according to an embodiment of the present invention.

Claims (12)

A soft liquid crystal lens array includes: a first flexible substrate; a first flexible transparent electrode layer disposed on the flexible substrate, which is composed of a soft nano metal wire; and a soft liquid crystal layer disposed on the soft liquid crystal layer The first flexible transparent electrode layer comprises two alignment layers and a soft spacer layer sandwiched between the two alignment layers, wherein the soft spacer layer comprises a plurality of soft spacers to form a space for accommodating the liquid crystal; a second flexible transparent electrode layer disposed on the flexible liquid crystal layer, which is formed by a soft nanowire; and a second flexible substrate disposed on the second flexible transparent electrode layer or the second soft transparent layer Between the electrode layer and the soft liquid crystal layer; wherein the second flexible transparent electrode layer comprises a patterned soft nanowire to form a graded electric field; wherein the second soft transparent electrode layer and the soft liquid crystal layer Contains a soft high-resistance film layer. The flexible liquid crystal lens array according to claim 1, wherein the soft high-resistance film layer is selected from the group consisting of ruthenium oxide, ruthenium nitride, ruthenium carbide, aluminum oxide, transparent polymer material, and combinations thereof. The flexible liquid crystal lens array of claim 2, wherein the second flexible substrate is disposed under the second flexible transparent electrode layer, and the second flexible transparent electrode layer further comprises a transparent protective layer. The flexible liquid crystal lens array according to claim 1, wherein the patterned soft nanowire is a pattern of a triangle, a rectangle, a hexagon, a circle, or a combination thereof. Patterned processing. The soft liquid crystal lens array according to claim 1, wherein the patterned soft nanowire is subjected to an alignment patterning process. The flexible liquid crystal lens array of claim 1, wherein the material of the first flexible substrate and the second flexible substrate transparent substrate is selected from the group consisting of glass, polyimide, polymethyl methacrylate, and polycarbonate. Ester, polyethylene naphthalate, polyethylene terephthalate, polyolefin, fluoropolymer, polyamide, organic oxime resin, polyether ketone, polyether ketone ketone, polynorbornene, poly Ester, polystyrene, cellulose triacetate and combinations thereof. The flexible liquid crystal lens array of claim 1, wherein the material of the nanowire is selected from the group consisting of silver, gold, iron, nickel, titanium, and combinations thereof. The flexible liquid crystal lens array of claim 1, wherein the soft spacer is a soft microcolumn having a width of no more than 100 micrometers (um). The flexible liquid crystal lens array of claim 1, wherein the soft spacer is a polymer wall, and the polymer walls are connected to each other. The flexible liquid crystal lens array according to claim 9, wherein the material of the polymer wall is selected from the group consisting of diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, and polyethylene diacrylate. Alcohol ester, polyethylene glycol dimethacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, urethane diacrylate, beta hydroxy methacrylate Ethyl ester, methyl acrylate, isobornyl methacrylate, isobornyl acrylate, ethyl methacrylate, 2-(2-ethoxyethoxy)ethyl acrylate, acrylic-3,5,5- Trimethylhexyl ester and combinations thereof. The flexible liquid crystal lens array of claim 1, wherein the soft spacer is a soft micro-cap, the opening of the flexible micro-cover is polygonal, and the sidewalls are connected to each other. The flexible liquid crystal lens array of claim 1, wherein the liquid crystal system is selected from the group consisting of a blue phase liquid Crystal, polymer liquid crystal, cholesteric liquid crystal, photoactive reactive liquid crystal, and combinations thereof.