阅读说明：本技术 光学装置 (Optical device ) 是由 李星珉 全炳建 金南焄 金正云 李荣晨 于 2020-03-26 设计创作，主要内容包括：本申请涉及光学装置。本申请提供了光学装置,所述光学装置可以用于眼部佩戴物如太阳镜或者AR(增强现实)或VR(虚拟现实)眼部佩戴物、建筑物的外墙或者车辆用天窗等的各种应用。本申请的一个目的是提供光学装置,所述光学装置防止由过多量或过少量的光调制材料或者光调制材料的热收缩等引起的缺陷。(The present application relates to optical devices. Optical devices are provided that can be used in various applications for eyewear such as sunglasses or AR (augmented reality) or VR (virtual reality) eyewear, exterior walls of buildings, or vehicle skylights, etc. An object of the present application is to provide an optical device that prevents defects caused by an excessive amount or an insufficient amount of a light modulation material or thermal shrinkage or the like of the light modulation material.)

1. An optical device, comprising:

a first outer substrate and a second outer substrate disposed to face each other;

an active liquid crystal film layer; and

the step-forming layer is formed on the substrate,

wherein the active liquid crystal film layer and the step-forming layer are encapsulated between the first and second outer substrates by an encapsulant, and

wherein the active liquid crystal film layer includes a region pressed by the step-forming layer and a region not pressed by the step-forming layer.

2. The optical device of claim 1, wherein the active liquid crystal film layer comprises:

two base film layers disposed to face each other; and

a liquid crystal material in the gap between the base film layers.

3. The optical device of claim 2, wherein an anisotropic dye is further included in the gap between the base film layers.

4. The optical device according to claim 2, wherein a size of a gap between the two base film layers facing each other in a region of the active liquid crystal film layer pressed by the step-forming layer is different from a size of a gap between the two base film layers facing each other in a region of the active liquid crystal film layer not pressed by the step-forming layer.

5. The optical device according to claim 4, wherein a ratio (100 x [ G1/G2]) of a dimension G1 of the gap in the region pressed by the step forming layer to a dimension G2 of the gap in the region not pressed by the step forming layer is 10% to 95%.

6. The optical device according to claim 1, wherein a ratio (100 x [ a2/a1]) of an area a2 of the step formation layer with respect to an area a1 of the active liquid crystal film layer is 70% to 98%.

7. The optical device according to claim 1, wherein a region of the active liquid crystal film layer pressed by the step-forming layer forms a light modulation region.

8. The optical device according to claim 1, wherein a region of the active liquid crystal film layer which is not pressed by the step-forming layer is present on at least one side of a region of the active liquid crystal film layer which is pressed by the step-forming layer.

9. The optical device according to claim 1, wherein a region of the active liquid crystal film layer not pressed by the step-forming layer forms a bezel surrounding a region of the active liquid crystal film layer pressed by the step-forming layer.

10. The optical device of claim 1, wherein the step-forming layer is a transparent polymer film layer, a plastic resin layer, or a curable resin layer.

11. The optical device of claim 1, further comprising a polarizing layer encapsulated between the first and second outer substrates by the encapsulant.

12. The optical device according to claim 11, wherein the polarizing layer is used as the step forming layer.

13. The optical device of claim 1, wherein at least one of the first and second outer substrates is a curved surface substrate.

14. The optical device of claim 13, wherein a difference between curvatures of the first and second outer substrates is 10% or less.

Technical Field

This application claims the benefit of priority based on korean patent application No. 10-2019-0035032, filed on 27/3/2019, the disclosure of which is incorporated herein by reference in its entirety.

The present application relates to optical devices.

Background

Various transmittance variable devices designed to be able to change transmittance using a liquid crystal compound are known. For example, an optical device using a so-called GH cell (guest host cell) to which a mixture of a host material and a dichroic dye guest is applied is known. Such a transmittance variable device is applied to various applications including eyewear such as sunglasses or glasses, building exterior walls, or sunroof of vehicles, etc.

In such a device, the liquid crystal layer contains a liquid crystal material filled in a gap formed between two substrate layers disposed oppositely, and light is modulated by adjusting the orientation of the liquid crystal material. Ideally, the liquid crystal material is completely filled in the space formed by the gap.

For example, as shown in fig. 1, if an excessive amount of liquid crystal material is present therein with respect to the volume of the space formed by the gap, an appearance defect may be caused by the liquid crystal material accumulated in the liquid crystal cell 1 or the convex portion 2 or the like in the liquid crystal cell 1 due to the excessive amount of liquid crystal material. Conversely, if a small amount of liquid crystal material is present therein with respect to the volume of the space formed by the gap, an appearance defect may also be caused due to a void generated in the liquid crystal layer.

Disclosure of Invention

Technical problem

The present application provides an optical device. An object of the present application is to provide an optical device that prevents defects caused by an excessive amount or an insufficient amount of a light modulation material or thermal shrinkage or the like of the light modulation material.

Technical scheme

In the physical properties mentioned herein, when measuring the temperature or pressure-affected results, the relevant physical properties are measured at room temperature and normal pressure unless otherwise specified.

The term room temperature is the natural temperature without heating or cooling, which can generally be any temperature in the range of about 10 ℃ to 30 ℃, or a temperature of about 23 ℃ or about 25 ℃. Further, unless otherwise indicated, temperature units herein are in degrees celsius.

The term atmospheric pressure is natural pressure without particular decrease or increase, which generally means a pressure of around 1 atmosphere, for example atmospheric pressure.

The optical device of the present application is an optical device capable of adjusting transmittance, and may be, for example, an optical device capable of switching at least between a transparent mode and a black mode.

The transparent mode is a state in which the optical device exhibits a relatively high transmittance, and the black mode is a state in which the optical device has a relatively low transmittance.

In one example, the optical device may have a transmittance of about 15% or greater, about 18% or greater, about 20% or greater, about 25% or greater, about 30% or greater, about 35% or greater, about 40% or greater, about 45% or greater, or about 50% or greater in the transparent mode. Further, the optical device may have a transmittance of about 20% or less, about 15% or less, about 10% or less, about 5% or less, or about 1% or less in the black mode.

The higher the transmittance in the transparent mode is more favorable, and the lower the transmittance in the black mode is more favorable, and therefore each of the upper limit and the lower limit is not particularly limited. In one example, the transmittance in the transparent mode may be about 100% or less, about 95% or less, about 90% or less, about 85% or less, about 80% or less, about 75% or less, about 70% or less, about 65% or less, or about 60% or less. The transmittance in the black mode may be about 0% or greater, about 1% or greater, about 2% or greater, about 3% or greater, about 4% or greater, about 5% or greater, about 6% or greater, about 7% or greater, about 8% or greater, about 9% or greater, or about 10% or greater.

The transmittance may be a linear transmittance. The term linear light transmittance may be a ratio of light (linear light) transmitted through the optical device in the same direction as an incident direction with respect to light incident on the optical device in a predetermined direction. In one example, the transmittance may be a measurement with respect to light incident in a direction parallel to the surface normal of the optical device (normal transmittance).

In the optical device of the present application, the light whose transmittance is controlled may be UV-a region ultraviolet light, visible light, or near infrared light. Therefore, the transmittance may be a transmittance for ultraviolet light, visible light, or near-infrared light, depending on the target light. According to the usual definition, UV-a range ultraviolet light is used to mean radiation with a wavelength in the range of 320nm to 380nm, visible light is used to mean radiation with a wavelength in the range of 380nm to 780nm, and near infrared light is used to mean radiation with a wavelength in the range of 780nm to 2000 nm.

The optical device of the present application is designed to be capable of switching at least between a transparent mode and a black mode. If necessary, the optical device may also be designed to be able to realize other modes than the transparent mode and the black mode, for example, various third modes such as a mode that can exhibit any transmittance between the transmittance of the transparent mode and the transmittance of the black mode.

Since the optical device comprises an active liquid crystal film layer, switching between such modes can be achieved. Here, the active liquid crystal film layer is a liquid crystal element that can be switched between at least two or more alignment states (for example, a first alignment state and a second alignment state) of the optical axis. Here, the optical axis may mean a long axis direction when the liquid crystal compound contained in the active liquid crystal film layer is a rod type, and may mean a normal direction of a disc plane when the liquid crystal compound contained in the active liquid crystal film layer is a disc (discotic) type. For example, in the case where the active liquid crystal film layer includes a plurality of liquid crystal compounds whose directions of optical axes are different from each other in any alignment state, the optical axis of the active liquid crystal film layer may be defined as an average optical axis (average optical axis), and in this case, the average optical axis may mean a vector sum of the optical axes of the liquid crystal compounds.

In the active liquid crystal film layer, the alignment state can be changed by applying energy, for example, applying a voltage. For example, the active liquid crystal film layer may have any one of a first alignment state and a second alignment state in a state where no voltage is applied, and may be switched to another alignment state when a voltage is applied.

The black mode may be implemented in any one of the first and second orientation states, and the transparent mode may be implemented in the other orientation state. For convenience, the black mode is described herein as being implemented in the first state, but the black mode may also be implemented in the second state.

In the optical device of the present application, the active liquid crystal film layer may be encapsulated between two outer substrates by an encapsulant. In the present specification, either one of the two outer substrates may be referred to as a first outer substrate, and the other may be referred to as a second outer substrate. However, the terms first and second, as used above, are names used to distinguish two outer substrates and do not define a sequential or perpendicular relationship between the two.

Here, the encapsulation is a state in which the active liquid crystal film layer is surrounded by the encapsulant between the two outer substrates. For example, all surfaces (e.g., top and bottom surfaces) and all sides of the active liquid crystal film layer may be surrounded by the encapsulant. Here, the fact that all surfaces of the active liquid crystal film layer are surrounded by the encapsulant is that all surfaces are substantially surrounded by the encapsulant, wherein a connection portion (e.g., a terminal portion) formed so that an external power source can be applied for switching of the active liquid crystal film layer may be outside the encapsulant. In addition, all the surface of the active liquid crystal film layer may be in direct contact with the encapsulant, and other elements (for example, a polarizing layer or a step-forming layer described below, etc.) may also be present between the surface of the active liquid crystal film layer and the encapsulant.

Such encapsulation may be performed with an adhesive, wherein the encapsulant may be an adhesive.

For example, the encapsulation structure may be achieved while the encapsulant (which is an adhesive) attaches the outer substrate, the active liquid crystal film layer, and/or other elements of the optical device (e.g., the polarizing layer or the step-forming layer) to each other. For example, the structure can be realized by: the outer substrate, the active liquid crystal film layer, the adhesive film (which forms the encapsulant), and/or other elements are laminated according to a desired structure and then compressed under a vacuum state.

As the adhesive, known materials may be used without particular limitation, and for example, known thermoplastic polyurethane (TPU: thermoplastic polyurethane) adhesive, TPS (thermoplastic starch) adhesive, polyamide adhesive, acrylic adhesive, polyester adhesive, EVA (ethylene vinyl acetate) adhesive, polyolefin adhesive such as polyethylene or polypropylene, or polyolefin elastomer adhesive (POE adhesive), or the like may be used. Such adhesives may be in the form of a film.

The optical device may include a step-forming layer encapsulated between the first and second outer substrates together with the active liquid crystal film layer by an encapsulant. The step-forming layer may be disposed on at least one surface of the active liquid crystal film layer. The term step-forming layer may mean a layer forming a step difference of a so-called cell gap in at least a specific portion of the active liquid crystal layer. That is, both the step-forming layer and the active liquid crystal film layer have a structure encapsulated between two outer substrates, and thus when adjusting the areas of the step-forming layer and the active liquid crystal film layer, a step may be formed since at least a portion of the area of the active liquid crystal film layer is pressed by the step-forming layer. Since the excessive light modulation material and/or voids existing in the cell gap of the active liquid crystal film layer are pushed out by the pressing force generated by such a structure, such a structure can be realized: wherein the light modulation material desirably fills a space created by the cell gap in the region pressed by the step formation layer.

Fig. 2 is a side view of an exemplary optical device, wherein the device includes an active liquid crystal film layer and a step-forming layer 300 encapsulated between two outer substrates 101, 102 by an encapsulant 400.

As shown in fig. 2, the active liquid crystal film layer may include two base film layers 201, 202 disposed opposite to each other. The two base film layers 201, 202 are bonded together by a so-called sealant 500 to form a gap in which a liquid crystal material is present. As described below, so-called anisotropic dyes may also be present in the space of the gap together with the liquid crystal material. As shown in fig. 2, in the active liquid crystal film layer, a region 2011 pressed by the step formation layer 300 and an unpressed region 2012 are generated by the action of the step formation layer 300 and the encapsulant 400. In such a structure, an excessive amount of light modulation material (liquid crystal material and/or anisotropic dye, etc.) or bubbles or the like moves to the non-compressed region 2012, and an ideal state is achieved in the compressed region 2011. In fig. 2, a broken line existing between the pressed region 2011 and the non-pressed region 2012 is a virtual line for distinguishing regions only on the drawing. Further, according to the above configuration, it is also possible to solve the so-called white spot problem caused by consumption of the light modulation material due to thermal shrinkage of the light modulation material (for example, liquid crystal material) according to the use state of the optical device.

Fig. 3 is a view separately showing the active liquid crystal film layer and the step-forming layer 300 in fig. 2.

As shown in fig. 3, in the above structure, in the region 2011 pressed by the step formation layer and the non-pressed region 2012, the gaps (so-called cell gaps) of the two base film layers disposed opposite in the active liquid crystal film layer are different from each other.

In one example, the ratio (100 xg 1/G2) of the gap (G1 in fig. 3) of the base film layers 201, 202 in the stepped-layer extruded region 2011 relative to the gap (G2 in fig. 3) of the base film layers 201, 202 in the uncompressed region 2012 may be in a range of about 10% to 95%. In another example, the ratio (100 xg 1/G2) may be about 11% or more, about 12% or more, about 13% or more, about 14% or more, about 15% or more, about 16% or more, about 17% or more, about 18% or more, about 19% or more, about 20% or more, about 21% or more, about 22% or more, about 23% or more, about 24% or more, about 25% or more, about 26% or more, about 27% or more, about 28% or more, about 29% or more, about 30% or more, about 31% or more, about 32% or more, about 33% or more, about 34% or more, about 35% or more, about 36% or more, about 37% or more, about 38% or more, about 39% or more, about 40% or more, About 41% or more, about 42% or more, about 43% or more, about 44% or more, about 45% or more, about 46% or more, about 47% or more, about 48% or more, about 49% or more, about 50% or more, about 51% or more, about 52% or more, about 53% or more, about 54% or more, about 55% or more, about 56% or more, about 57% or more, about 58% or more, about 59% or more, about 60% or more, about 61% or more, about 62% or more, about 63% or more, about 64% or more, about 65% or more, about 66% or more, about 67% or more, about 68% or more, about 69% or more, about 70% or more, about 71% or more, about 72% or more, about 73% or more, about 45% or more, about 46% or more, about 73% or more, or about 72% or more, or about 73% or more, or less, or more, or less, or more than or less, or more than or less than or, About 74% or more, about 75% or more, about 76% or more, about 77% or more, about 78% or more, about 79% or more, about 80% or more, about 81% or more, about 82% or more, about 83% or more, about 84% or more, about 85% or more, about 86% or more, about 87% or more, about 88% or more, about 89% or more, about 90% or more, about 91% or more, about 92% or more, about 93% or more, about 94% or more, or further about 94% or less, about 93% or less, about 92% or less, about 90% or less, about 91% or less, about 90% or less, about 89% or less, about 88% or less, about 87% or less, about 86% or less, about 85% or less, about 84% or less, about 88% or less, about 87% or less, about 86% or less, about 85% or less, about 84% or less, or less, About 83% or less, about 82% or less, about 81% or less, about 80% or less, about 79% or less, about 78% or less, about 77% or less, about 76% or less, about 75% or less, about 74% or less, about 73% or less, about 72% or less, about 71% or less, about 70% or less, about 69% or less, about 68% or less, about 67% or less, about 66% or less, about 65% or less, about 64% or less, about 63% or less, about 62% or less, about 61% or less, about 60% or less, about 59% or less, about 58% or less, about 57% or less, about 56% or less, about 55% or less, about 54% or less, about 53% or less, about 52% or less, or about 51% or less.

Such a ratio can be adjusted by, for example, controlling the cell gap of the active liquid crystal film layer, the thickness of the step formation layer, and/or the packing pressure generated by the encapsulant, and the like.

In one example, in the above structure, a ratio (100 × a2/a1) of an area (a2) of the step formation layer with respect to an area (a1) of the active liquid crystal film layer may be in a range of 70% to 98%. The ratio (100 xa 2/a1) may be about 71% or more, about 72% or more, about 73% or more, about 74% or more, about 75% or more, about 76% or more, about 77% or more, about 78% or more, about 79% or more, about 80% or more, about 81% or more, about 82% or more, about 83% or more, about 84% or more, about 85% or more, about 86% or more, about 87% or more, about 88% or more, about 89% or more, about 90% or more, about 91% or more, about 92% or more, about 93% or more, about 94% or more, about 95% or more, about 96% or more, or about 97% or more, or about 96%, about 95% or more, or about 95% or more, About 94% or less, about 93% or less, about 92% or less, about 91% or less, about 90% or less, about 89% or less, about 88% or less, about 87% or less, about 86% or less, about 85% or less, about 84% or less, about 83% or less, about 82% or less, about 81% or less, about 80% or less, about 79% or less, about 78% or less, about 77% or less, about 76% or less, about 75% or less, about 74% or less, about 73% or less, about 72% or less, or about 71% or less. The areas are areas when the active liquid crystal film layer and the step forming layer are viewed from the top surface or the bottom surface, respectively. In addition, the area of the active liquid crystal film layer may be the entire area of the film layer or the area of the region (a in fig. 3) formed inside the sealant 500.

By controlling the ratio, the volume of the region in the cell gap of the active liquid crystal film layer which is not pressed by the step formation layer can be adjusted, so that the excessive light modulation material and/or bubbles can be appropriately pushed out.

In such a structure, in one example, the surface of the region of the active liquid crystal film layer pressed by the step-forming layer may form a light modulation region, i.e., a region in which transmittance is adjusted, in the optical device.

In the active liquid crystal film layer, the two regions 2011, 2012 may exist in various forms. For example, as exemplarily shown in fig. 4, when viewed from the top surface or the bottom surface, a region 2012 of the active liquid crystal film layer, which is not pressed by the step-forming layer, may exist on at least one side of a region 2011 pressed by the step-forming layer.

In another example, as shown in fig. 5, when viewed from the top surface or the bottom surface, a region 2012 of the active liquid crystal film layer that is not pressed by the step-forming layer may be formed as a bezel surrounding a region 2011 of the active liquid crystal film layer that is pressed by the step-forming layer.

The form may be changed according to purposes. For example, the above may be changed in consideration of a desired volume of the region 2012 not pressed by the step forming layer or the design of the optical device, or the like.

The specific type of each structure applied to the above-described structures is not particularly limited, and known structures may be applied.

For example, in one example, as the light modulation material contained in the gap between the base film layers of the active liquid crystal film layer, a liquid crystal material may be generally applied, wherein the type of the specific liquid crystal material is not particularly limited.

In one example, the active liquid crystal film layer may be a so-called guest-host liquid crystal film layer. In this case, the anisotropic dye may be contained in the gap together with the liquid crystal material (liquid crystal host). As a liquid crystal layer utilizing the so-called guest-host effect, such a liquid crystal film layer includes a liquid crystal layer in which anisotropic dyes are aligned according to the alignment direction of a liquid crystal material (liquid crystal host). The alignment direction of the liquid crystal body may be adjusted according to the application of the external energy.

As such a liquid crystal host, a general kind of liquid crystal compound for realizing the guest-host effect can be used without particular limitation.

For example, a smectic liquid crystal compound, a nematic liquid crystal compound, or a cholesteric liquid crystal compound can be used as the liquid crystal host. Such liquid crystal compounds may be in the form of rods or may be in the form of disks.

As such a liquid crystal compound, a liquid crystal compound having a clearing point of, for example, about 40 ℃ or more, about 50 ℃ or more, about 60 ℃ or more, about 70 ℃ or more, about 80 ℃ or more, about 90 ℃ or more, about 100 ℃ or more, or about 110 ℃ or more, or having a phase transition point (i.e., a phase transition point of a liquid crystal phase such as a nematic phase to an isotropic phase) in the above range may be selected. In one example, the clearing point or phase change point can be about 160 ℃ or less, about 150 ℃ or less, or about 140 ℃ or less.

The liquid crystal compound may have negative or positive dielectric anisotropy. The absolute value of the dielectric constant anisotropy may be appropriately selected in consideration of the purpose. For example, the dielectric constant anisotropy may be greater than 3 or greater than 7, or may be less than-2 or less than-3.

The optical anisotropy (β n) of the liquid crystal compound may be about 0.01 or more, or about 0.04 or more. In another example, the optical anisotropy of the liquid crystal compound may be about 0.3 or less, or about 0.27 or less.

The liquid crystal compound that can be used as the liquid crystal host of the guest-host liquid crystal layer is known to those skilled in the art, and the liquid crystal compound can be freely selected therefrom.

In the case of a so-called guest-host liquid crystal film layer, the liquid crystal layer (the gap formed between the two base film layers) may contain an anisotropic dye together with the liquid crystal host. The term "dye" may mean a material capable of strongly absorbing and/or modifying light in at least a part of or the entire range of the visible light region (for example, a wavelength range of 380nm to 780 nm), and the term "anisotropic dye" may mean a material capable of anisotropically absorbing light in at least a part of or the entire range of the visible light region.

As the anisotropic dye, for example, a known dye known to have a characteristic that can be aligned according to the alignment state of the liquid crystal host can be selected and used. For example, an azo dye, an anthraquinone dye, or the like may be used as the anisotropic dye, and the liquid crystal layer may further contain one or two or more dyes to achieve light absorption in a wide wavelength range.

The dichroic ratio of the anisotropic dye may be appropriately selected in consideration of the purpose. For example, the dichroic ratio of the anisotropic dye may be 5 or more to 20 or less. For example, in the case of a p-type dye, the term "dichroic ratio" may mean a value obtained by dividing the absorption of polarized light parallel to the long axis direction of the dye by the absorption of polarized light parallel to the direction perpendicular to the long axis direction. The anisotropic dye may have the dichroic ratio at least in some wavelengths or any wavelength or the whole range of the wavelength range of the visible light region, for example in the wavelength range of about 380nm to 780nm or about 400nm to 700 nm.

The content of the anisotropic dye in the liquid crystal layer may be appropriately selected in consideration of the purpose. For example, the content of the anisotropic dye may be selected in the range of 0.1 to 10% by weight, based on the total weight of the liquid crystal host and the anisotropic dye. The ratio of the anisotropic dye may be changed in consideration of desired transmittance, solubility of the anisotropic dye in the liquid crystal host, and the like.

The liquid crystal layer essentially comprises a liquid crystal host and an anisotropic dye, and may, if necessary, also comprise other optional additives according to known forms. As an example of the additive, a chiral dopant or a stabilizer may be exemplified, but is not limited thereto.

The thickness of the liquid crystal layer (thickness of the cell gap) may be appropriately selected in consideration of the purpose (e.g., a desired degree of anisotropy, etc.). In one example, the thickness of the liquid crystal layer may be about 0.01 μm or more, 0.05 μm or more, 0.1 μm or more, 0.5 μm or more, 1 μm or more, 1.5 μm or more, 2 μm or more, 2.5 μm or more, 3 μm or more, 3.5 μm or more, 4 μm or more, 4.5 μm or more, 5 μm or more, 5.5 μm or more, 6 μm or more, 6.5 μm or more, 7 μm or more, 7.5 μm or more, 8 μm or more, 8.5 μm or more, 9 μm or more, or 9.5 μm or more. By thus controlling the thickness, an optical device having a large difference between the transmittance in the transparent state and the transmittance in the black state, that is, a device having a large contrast ratio can be realized. The higher the contrast ratio that can be achieved with a thicker thickness, and thus the thickness is not particularly limited, but it may be generally about 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less. Here, the thickness is also the thickness of the region pressed by the step-forming layer.

The active liquid crystal film layer may be switched between a first alignment state and a second alignment state different from the first alignment state. The switching may be controlled, for example, by applying external energy such as a voltage. For example, either one of the first orientation state and the second orientation state may be held in a state where no voltage is applied, and then switched to the other orientation state by voltage application.

In one example, the first and second alignment states may each be selected from a horizontal alignment, a vertical alignment, a twisted nematic alignment, or a cholesteric alignment state. For example, in the black mode, the active liquid crystal film layer or the liquid crystal layer may be in at least a horizontal alignment, a twisted nematic alignment, or a cholesteric alignment, and in the transparent mode, the active liquid crystal film layer or the liquid crystal layer may be in a homeotropic alignment state, or a horizontal alignment state having an optical axis in a direction different from the horizontal alignment of the black mode. The active liquid crystal film layer may be an element of a normally black mode (normal black mode) in which a black mode is realized in a state where no voltage is applied, or may be a normally transparent mode (normal transparent mode) in which a transparent mode is realized in a state where no voltage is applied.

A method of determining a direction in which an optical axis of a liquid crystal layer is formed in an aligned state of the liquid crystal layer is known. For example, the direction of the optical axis of the liquid crystal layer may be measured by using another polarizing plate whose optical axis direction is known, which may be measured using a known measuring instrument such as a polarimeter (e.g., P-2000 from Jascp).

A method of realizing an active liquid crystal film layer of a normally transparent mode or a normally black mode by adjusting dielectric constant anisotropy of a liquid crystal host, an alignment direction of an alignment film for aligning the liquid crystal host, or the like is known.

As described above, the active liquid crystal film layer may include two base film layers disposed opposite to each other. The active liquid crystal film layer may further include a spacer that maintains a gap between the two base film layers and/or a sealant that attaches the base film layers in a state of maintaining the gap between the two base film layers that are oppositely disposed. As the spacer and/or the sealant, known materials may be used without particular limitation.

As the base film layer, for example, an inorganic film made of glass or the like, or a plastic film may be used. As the plastic film, a TAC (triacetyl cellulose) film; COP (cyclic olefin copolymer) films such as norbornene derivatives; acrylic films such as PMMA (poly (methyl methacrylate)), PC (polycarbonate) films, PE (polyethylene) films, PP (polypropylene) films, PVA (polyvinyl alcohol) films, DAC (diacetylcellulose) films, Pac (polyacrylate) films, PEs (polyethersulfone) films, PEEK (polyetheretherketone) films, PPs (polyphenylsulfone) films, PEI (polyetherimide) films, PEN (polyethylene naphthalate) films, PET (polyethylene terephthalate) films, PI (polyimide) films, PSF (polysulfone) films, PAR (polyarylate) films, fluorine resin films, or the like, but not limited thereto.

Among the various materials described above, a material capable of being pressed by the step-forming layer may be suitably used as the base film layer.

The thickness of the base film layer is not particularly limited, and may be, for example, in the range of about 50 μm to about 200 μm.

In the active liquid crystal film layer, a conductive layer and/or an alignment film may be present on one surface of the base film layer (e.g., a surface of the base film layer facing the active liquid crystal film layer).

The conductive layer present on the surface of the base film layer is a structure for applying a voltage to the active liquid crystal film layer, wherein a known conductive layer may be applied without particular limitation. As the conductive layer, for example, a conductive polymer, a conductive metal, a conductive nanowire, or a metal oxide such as ITO (indium tin oxide) or the like can be applied. In the present application, examples of the applicable conductive layer are not limited to the above, and all kinds of conductive layers known in the art to be applicable to the active liquid crystal film layer may be used.

In one example, an alignment film is present on the surface of the base film layer. For example, a conductive layer may be first formed on one surface of a base film layer, and an alignment film may be formed on the top. The alignment film is a structure for controlling the orientation of a liquid crystal host included in an active liquid crystal film layer, wherein a known alignment film may be applied without particular limitation. The alignment film known in the industry includes a rubbing alignment film, a photo-alignment film, or the like, and the alignment film that can be used in the present application is a known alignment film, which is not particularly limited.

The orientation direction of the alignment film may be controlled to achieve proper orientation of the optical axis. For example, the alignment directions of the two alignment film layers formed on each side of the two base films disposed opposite to each other may form an angle in the range of about-10 degrees to 10 degrees, an angle in the range of-7 degrees to 7 degrees, an angle in the range of-5 degrees to 5 degrees, or an angle in the range of-3 degrees to 3 degrees with each other, or may be substantially parallel to each other. In another example, the alignment directions of the two alignment films may form an angle in a range of about 80 degrees to 100 degrees, an angle in a range of about 83 degrees to 97 degrees, an angle in a range of about 85 degrees to 95 degrees, or an angle in a range of about 87 degrees to 92 degrees, or may be substantially perpendicular to each other.

Since the direction of the optical axis of the active liquid crystal film layer is determined according to such an orientation direction, the orientation direction can be determined by checking the direction of the optical axis of the active liquid crystal film layer.

The shape of the active liquid crystal film layer having such a structure is not particularly limited, it may be determined according to the application use of the optical device, and it is generally in the form of a film or a sheet.

The type of the step-forming layer included in the optical device is also not particularly limited. For example, all transparent materials having an appropriate thickness so as to be able to form a step in an optical device can be used as the step forming layer.

In one example, the step-forming layer may be a transparent polymer film. Here, the term transparent may mean a state in which: wherein the linear light transmittance is about 30% or more, about 35% or more, about 40% or more, about 45% or more, or about 50% or more, or about 100% or less, about 95% or less, about 90% or less, about 85% or less, about 80% or less, about 75% or less, about 70% or less, about 65% or less, or about 60% or less. The reference light at this time may be ultraviolet light, visible light, near infrared light, or the like, and in one example, the reference light may be light having a wavelength of about 550 nm.

As the transparent polymer film, various materials are known, and for example, TAC (triacetyl cellulose) film; COP (cyclic olefin copolymer) films such as norbornene derivatives; acrylic films such as PMMA (poly (methyl methacrylate)), PC (polycarbonate) films, PE (polyethylene) films, PP (polypropylene) films, PVA (polyvinyl alcohol) films, DAC (diacetylcellulose) films, Pac (polyacrylate) films, PEs (polyethersulfone) films, PEEK (polyetheretherketone) films, PPs (polyphenylsulfone) films, PEI (polyetherimide) films, PEN (polyethylene naphthalate) films, PET (polyethylene terephthalate) films, PI (polyimide) films, PSF (polysulfone) films, PAR (polyarylate) films, or fluororesin films, but not limited thereto.

A curable resin layer or a plastic resin layer may be applied as the step forming layer. That is, the step formation layer may be formed by: a curable resin composition or a plastic resin composition or the like is applied to form a layer so that a step can be formed in an appropriate position and with an appropriate thickness in an optical device. At this time, as long as the curable resin layer or the plastic resin layer exhibits the above transparency, it may be applied without particular limitation, for example, a curable resin layer or a plastic resin layer capable of forming an adhesive resin layer or a pressure-sensitive adhesive resin layer, or any other curable resin layer or plastic resin layer may be generally applied. For example, the material for forming the curable resin layer or the plastic resin layer may be exemplified based on an epoxy compound: acrylate-based, urethane-based, rubber-based, or silicon-based oligomeric or polymeric materials, and the like, but are not limited thereto.

The thickness of the step forming layer can be controlled by those skilled in the art according to the desired step. For example, the thickness may be about 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, 35 μm or more, or about 40 μm or more, or may be about 300 μm or less, 280 μm or less, 260 μm or less, 240 μm or less, 220 μm or less, 200 μm or less, 180 μm or less, 160 μm or less, 140 μm or less, 120 μm or less, or 100 μm or less, but it may be changed according to purposes.

The type of outer substrate applied to the optical device is also not particularly limited. As the outer substrate, for example, an inorganic substrate made of glass or the like, or a plastic substrate may be used. As the plastic substrate, a TAC (triacetyl cellulose) film; COP (cyclic olefin copolymer) films such as norbornene derivatives; acrylic films such as PMMA (poly (methyl methacrylate)), PC (polycarbonate) films, PE (polyethylene) films, PP (polypropylene) films, PVA (polyvinyl alcohol) films, DAC (diacetylcellulose) films, Pac (polyacrylate) films, PEs (polyethersulfone) films, PEEK (polyetheretherketone) films, PPs (polyphenylsulfone) films, PEI (polyetherimide) films, PEN (polyethylene naphthalate) films, PET (polyethylene terephthalate) films, PI (polyimide) films, PSF (polysulfone) films, PAR (polyarylate) films, fluorine resin films, or the like, but not limited thereto.

When the outer substrate has optical anisotropy, the angle formed by the slow axes of the oppositely disposed outer substrates may be, for example, in the range of about-10 degrees to 10 degrees, in the range of-7 degrees to 7 degrees, in the range of-5 degrees to 5 degrees, or in the range of-3 degrees to 3 degrees, or may be substantially parallel.

The thickness of the outer substrate is not particularly limited, and may be, for example, about 0.3mm or more. In another example, the thickness may be about 0.5mm or greater, about 0.7mm or greater, about 1mm or greater, about 1.5mm or greater, or about 2mm or greater, and may also be 10mm or less, 9mm or less, 8mm or less, 7mm or less, 6mm or less, 5mm or less, 4mm or less, 3mm or less, about 2mm or less, or about 1mm or less.

The outer substrate may be a flat substrate, or may be a substrate having a curved surface shape. For example, the two outer substrates may be both flat substrates while having a curved surface shape, or either one may be a flat substrate and the other may be a substrate having a curved surface shape. Here, in the case of simultaneously having a curved surface shape, the respective curvatures or radii of curvature may be the same or different.

In this specification, the curvature or radius of curvature may be measured in a manner known in the industry, for example, using a non-contact device such as a 2D profile laser sensor, a color confocal line sensor, or a 3D measuring confocal microscope. Methods of measuring curvature or radius of curvature using such devices are known.

With respect to the substrate, for example, when the curvatures or radii of curvature on the front surface and the back surface are different, the respective curvatures or radii of curvature of the opposing surfaces (i.e., the curvature or radius of curvature of the surface facing the second outer substrate in the case of the first outer substrate, and the curvature or radius of curvature of the surface facing the first outer substrate in the case of the second outer substrate) may be referred to. Furthermore, when the relevant surface has portions where the curvature or radius of curvature is not constant and different, the maximum curvature or radius of curvature, or the minimum curvature or radius of curvature, or the average curvature or radius of curvature may be referenced.

The difference between the curvatures or radii of curvature of the two substrates may be within 10%, within 9%, within 8%, within 7%, within 6%, within 5%, within 4%, within 3%, within 2%, or within 1%. When the large curvature or radius of curvature is C_LAnd a small curvature or radius of curvature C_SWhen the curvature or the difference between the radii of curvature is 100 × (C)_L-C_S)/C_SThe calculated value. Further, the lower limit of the curvature or the difference between the radii of curvature is not particularly limited. Since the difference in curvature or radius of curvature of the two outer substrates may be the same, the difference in curvature or radius of curvature may be 0% or greater, or greater than 0%.

Such control of the curvature or radius of curvature is useful in a structure in which a source liquid crystal film layer or the like is encapsulated by an adhesive film as in the optical device of the present application.

When both the first and second outer substrates are curved surfaces, both curvatures may have the same sign. In other words, the two outer substrates may be bent in the same direction. That is, in the above case, both the center of curvature of the first outer substrate and the center of curvature of the second outer substrate exist in the same portions of the upper and lower portions of the first and second outer substrates.

The specific range of each curvature or radius of curvature of the first and second outer substrates is not particularly limited. In one example, the radius of curvature of each substrate can be 100R or greater, 200R or greater, 300R or greater, 400R or greater, 500R or greater, 600R or greater, 700R or greater, 800R or greater, or 900R or greater, or can be 10,000R or less, 9,000R or less, 8,000R or less, 7,000R or less, 6,000R or less, 5,000R or less, 4,000R or less, 3,000R or less, 2,000R or less, 1,900R or less, 1,800R or less, 1,700R or less, 1,600R or less, 1,500R or less, 1,400R or less, 1,300R or less, 1,200R or less, 1,100R or less, or 1,050R or less. Here, R represents a bending gradient of a circle having a radius of 1 mm. Therefore, 100R here is, for example, the degree of curvature of a circle having a radius of 100mm or the radius of curvature of such a circle. Of course, in the case of a flat surface, the curvature is zero and the radius of curvature is infinite.

The first and second outer substrates may have the same or different radii of curvature within the above range. In one example, when the curvatures of the first and second outer substrates are different from each other, the radius of curvature of the substrate having a large curvature therein may be in the above range. In one example, when the curvatures of the first and second outer substrates are different from each other, the substrate having a large curvature may be a substrate disposed in a gravitational direction when the optical device is used.

That is, for encapsulation, an autoclave process using an adhesive film may be performed as described below, and in this process, high temperature and high pressure are generally applied. However, in some cases, for example, when the adhesive film applied to the package is stored at a high temperature for a long time after such an autoclave process, some reflow or the like occurs, so that there may be a problem that the outer substrate is widened. If this occurs, a force may act on the encapsulated active liquid crystal film layer and bubbles may be formed inside. However, when the curvature or the radius of curvature between the substrates is controlled as described above, even if the adhesive force generated by the adhesive film is reduced, the net force as the sum of the restoring force and the gravity may function to prevent the widening and also to withstand the same process pressure as the autoclave.

The optical device may further include a polarizing layer together with the active liquid crystal film layer. Such polarizing layers may also be encapsulated by an encapsulant. Fig. 6 is a diagram when a polarizing layer 600 is added to the structure of fig. 2. As shown, a polarizing layer 600 may be disposed on at least one side of the active liquid crystal film layer. However, as described below, the step-forming layer 300 itself may be a polarizing layer, and in this case, the structure of the optical device as shown in fig. 2 may be formed. As the polarizing layer, for example, an absorption type linear polarizing layer, that is, a polarizing layer having a light absorption axis formed in one direction and a light transmission axis formed substantially perpendicular to the light absorption axis may be used.

Assuming that the blocking state is achieved in the first alignment state of the active liquid crystal film layer, the polarizing layer may be disposed on the optical device such that an angle formed by an average optical axis (vector sum of optical axes) in the first alignment state and a light absorption axis of the polarizing layer is 80 to 100 degrees or 85 to 95 degrees, or it is substantially vertical, or the polarizing layer may be disposed on the optical device such that the angle is 35 to 55 degrees or about 40 to 50 degrees or about 45 degrees.

When the alignment direction of the alignment film is used as a reference, the alignment directions of the alignment films formed on each side of the two base film layers disposed opposite to each other of the active liquid crystal film layer as described above may be formed at an angle in the range of about-10 to 10 degrees, an angle in the range of-7 to 7 degrees, an angle in the range of-5 to 5 degrees, or an angle in the range of-3 to 3 degrees to each other, or in the case of being substantially parallel to each other, an angle formed by the alignment direction of any one of the two alignment films and the light absorption axis of the polarizing layer may be 80 to 100 degrees or 85 to 95 degrees, or may be substantially perpendicular.

In another example, the alignment directions of the two alignment films may form an angle in a range of about 80 to 100 degrees, an angle in a range of about 83 to 97 degrees, an angle in a range of about 85 to 95 degrees, or an angle in a range of about 87 to 92 degrees, or in the case of being substantially perpendicular to each other, the angle formed by the alignment direction of the alignment film disposed closer to the polarizing layer and the light absorption axis of the polarizing layer of the two alignment films may be 80 to 100 degrees or 85 to 95 degrees, or may be substantially perpendicular.

For example, as shown in fig. 6, the active liquid crystal film layer and the polarizing layer may be disposed in a state in which: the layers are laminated with each other so that the optical axis (average optical axis) in the first alignment direction of the active liquid crystal film layer and the light absorption axis of the polarizing layer are in the above relationship. In one example, when the polarizing layer is a polarizing coating layer which will be described below, a structure in which the polarizing coating layer exists inside the active liquid crystal film layer can also be realized. For example, the conductive layer, the polarizing coating layer, and the alignment film described above may be sequentially formed on at least one base film layer.

The kind of polarizing layer that can be applied in the optical device of the present application is not particularly limited. For example, as the polarizing layer, a conventional material used for a conventional LCD and the like, such as a PVA (poly (vinyl alcohol)) polarizing layer, or a polarizing layer realized by a coating method, such as a polarizing coating layer containing a Lyotropic Liquid Crystal (LLC) or a Reactive Mesogen (RM) and a dichroic dye, may be used. In the present specification, the polarizing layer realized by the coating method as described above may be referred to as a polarizing coating layer. As the lyotropic liquid crystal, known liquid crystals may be used without any particular limitation, and for example, a lyotropic liquid crystal capable of forming a lyotropic liquid crystal layer having a dichroic ratio of about 30 to 40 may be used. On the other hand, when the polarizing coating layer contains a Reactive Mesogen (RM) and a dichroic dye, as the dichroic dye, a linear dye may be used, or a discotic dye may also be used.

The optical device of the present application may comprise only one active liquid crystal film layer and one polarizing layer as described above. Thus, the optical device may comprise only one active liquid crystal film layer and only one polarizing layer.

In one example, the polarizing layer may also serve as a step forming layer by adjusting the area and thickness of the polarizing layer itself.

The optical device may also include any necessary configuration other than the above configurations, for example, known configurations such as a retardation layer, an optical compensation layer, an antireflection layer, and a hard coat layer are included in place.

Such an optical device may be manufactured in any manner. For example, the optical device may be manufactured by: according to a desired structure, the outer substrate, the adhesive film (constituting the encapsulant), the step forming layer, the active liquid crystal film layer, and/or other components are laminated, and then the laminated body is applied to an extrusion process such as an autoclave process. In this process, a desired structure may be formed by step forming and pressing.

At this time, the production of the laminate can be performed, for example, by applying a known lamination technique.

Subsequently, the encapsulation may be completed by a bonding process such as an autoclave process. The conditions of the autoclave process are not particularly limited, and it may be carried out at an appropriate temperature and pressure, for example, according to the type of adhesive film applied. Typical autoclave processes have temperatures of about 80 ℃ or higher, 90 ℃ or higher, 100 ℃ or higher, and pressures of 2 atmospheres or greater, but are not limited thereto. The upper limit of the process temperature can be about 200 ℃ or less, 190 ℃ or less, 180 ℃ or less, or about 170 ℃ or less, and the upper limit of the process pressure can be about 10 atmospheres or less, 9 atmospheres or less, 8 atmospheres or less, 7 atmospheres or less, or about 6 atmospheres or less.

Such optical devices may be used in various applications, for example, may be used for eyewear such as sunglasses or AR (augmented reality) or VR (virtual reality) eyewear, exterior walls of buildings or vehicle skylights, and the like.

In one example, the optical device itself may be a vehicle sunroof.

For example, in an automobile including a vehicle body in which at least one opening is formed, an optical device or a sunroof for a vehicle attached to the opening may be mounted and used.

At this time, when the curvatures or the radii of curvature of the outer substrates are different from each other, the substrate having a smaller radius of curvature (i.e., the substrate having a larger curvature) may be arranged in the gravity direction.

Advantageous effects

Optical devices are provided that can be used in various applications for eyewear such as sunglasses or AR (augmented reality) or VR (virtual reality) eyewear, exterior walls of buildings, or vehicle skylights, etc. An object of the present application is to provide an optical device that prevents defects caused by an excessive amount or an insufficient amount of a light modulation material or thermal shrinkage or the like of the light modulation material.

Drawings

Fig. 1 is a diagram for explaining a problem of a conventional active liquid crystal film layer.

Fig. 2 to 6 are explanatory views for explaining an optical device of the present application.

Fig. 7 and 8 are views for observing the external appearance of the optical devices of examples 1 and 2, respectively.

Fig. 9 is a view for observing the external appearance of the optical device of comparative example 1.

Detailed Description

Hereinafter, the present application will be described in detail by examples and comparative examples, but the scope of the present application is not limited to the following examples.

Example 1.

An optical device is manufactured by: a guest-host active liquid crystal film layer (cell gap: about 12 μm, base film layer type: PET (poly (ethylene terephthalate)) film, liquid crystal/dye mixture type: a mixture of MAT-16-969 liquid crystal of Merck and an anisotropic dye (BASF, X12)) as an active liquid crystal film layer and a polarizing layer (thickness: about 100 μm) based on a PVA (polyvinyl alcohol) film were encapsulated between two outer substrates with a thermoplastic polyurethane adhesive film (thickness: about 0.38mm, manufacturer: Argotec, product name: ArgoFlex).

Here, a glass substrate having a thickness of about 3mm is used as the outer substrate, and the two outer substrates have a radius of curvature of about 4,000R.

Here, a rectangular film layer having a horizontal length of about 850mm and a vertical length of about 600mm when viewed from the top was applied as the active liquid crystal film layer, and a rectangular film layer having a horizontal length of about 830mm and a vertical length of about 580mm when viewed from the top was applied as the polarizing layer based on the PVA film. Here, the horizontal length and the vertical length of the active liquid crystal film layer are the lengths of the inner regions of the sealant that maintain the gap between the base film layers.

The first external substrate 100, the adhesive film (forming the encapsulant 400), the polarizing layer 300, the active liquid crystal film layer, the adhesive film (forming the encapsulant 400), and the second external substrate 102 are disposed such that the structure shown in fig. 2 is formed, and the adhesive film (forming the encapsulant 400) is also disposed on the side surfaces of the active liquid crystal film layer and the polarizing layer. Here, the polarizing layer and the active liquid crystal film layer are disposed such that their centers coincide with each other.

Subsequently, an autoclave process is performed at a temperature of about 100 ℃ and a pressure of about 2 atmospheres to manufacture the optical device.

Example 2.

An optical device was manufactured in the same manner as in example 1, except that the polarizing layer was not used as the step-forming layer, but a separate polymer film was applied as the step-forming layer. In example 2, a film having the same horizontal and vertical lengths as those of the active liquid crystal film layer (width: about 850mm, height: about 600mm or so) was applied as the polarizing layer. As the polymer film forming the step-forming layer, a PET (poly (ethylene terephthalate)) film is applied, and a separate polymer film is disposed on the outside of the active liquid crystal film layer in consideration of the anisotropy of the PET film. The added film has a horizontal length of about 830mm, a vertical length of about 580mm, and a thickness in the range of about 40 μm to 95 μm when viewed from the top. The other structures used were the same as those of example 1 except for the polarizing layer and the PET film.

The first external substrate 100, the adhesive film (forming the encapsulant 400), the polarizing layer 600, the active liquid crystal film layer, the PET film 300, the adhesive film (forming the encapsulant 400), and the second external substrate 102 are disposed such that the structure shown in fig. 6 is formed, and the adhesive film (forming the encapsulant 400) is also disposed on the side surfaces of the active liquid crystal film layer and the polarizing layer. Here, the polarizing layer, the PET film, and the active liquid crystal film layer are disposed such that their centers coincide with each other.

Subsequently, an autoclave process is performed at a temperature of about 100 ℃ and a pressure of about 2 atmospheres to manufacture the optical device.

Comparative example 1.

An optical device was manufactured in the same manner as in example 1, except that a PVA film having the same area and the same horizontal and vertical lengths as those of the active liquid crystal film layer was applied as the polarizing layer.

Fig. 7 and 8 are photographs for confirming the external appearance of the optical devices of examples 1 and 2, respectively, and fig. 9 is a photograph for confirming the external appearance of the optical device of comparative example 1. As shown in the figure, in the case of examples 1 and 2, no defect was observed in the region pressed by the step-forming layer, but in the case of comparative example 1, many defects such as spots were confirmed.