Optical device

Abstract

An optical device is provided in the present application. The optical device of the present application has varying transmittance and improved appearance defects, such as reduction of wrinkles that may occur by lamination of a liquid crystal element and an outer substrate. Such optical device can be used for various applications such as eyewear, for example, sunglasses or AR (augmented reality) or VR (virtual reality) eyewear, an outer wall of a building or a sunroof for a vehicle.

Claims

1. An optical device comprising: first and second outer substrates; a liquid crystal element positioned between the first and second outer substrates; and an adhesive film, wherein the liquid crystal element comprises a structure in which a first base layer, a liquid crystal layer and a second base layer are sequentially laminated, wherein the adhesive film forms an autoclaved encapsulation structure between the first outer substrate and the liquid crystal element, between the second outer substrate and the liquid crystal element and on a side of the liquid crystal element, wherein one or more of the first base layer and or the second base layer have a flexural rigidity (D) of 2.2*10.sup.−4 N.Math.m or more, the flexural rigidity (D) as represented by Equation 1 below $\begin{array}{cc}D=\frac{{\mathrm{Eh}}_e^3}{12\left(1-{\upsilon }^2\right)}& \left[\mathrm{Equation}1\right]\end{array}$ wherein, D is the flexural rigidity of the base layer, E is a Young's modulus of the base layer, h.sub.e is a thickness of the base layer, and υ is a Poisson's ratio of the base layer.

2. The optical device according to claim 1, wherein the first base layer and the second base layer each have a flexural rigidity (D) of 2.2*10.sup.−4 N.Math.m or more, as represented by Equation 1.

3. The optical device according to claim 1, wherein the first base layer and the second base layer each have a Young's modulus of 1*10.sup.9 N/m.sup.2 to 1*10.sup.10 N/m.sup.2.

4. The optical device according to claim 1, wherein the first base layer and the second base layer each have a thickness (h.sub.e) of 10 μm to 1,000 μm.

5. The optical device according to claim 1, wherein the first base layer and the second base layer are each independently a PEN (polyethylene-naphthalate) film, a PI (polyimide) film, a COP (cyclo-olefin polymer) film, a TAC (tri-acetyl-cellulose) film, a PET (polyethyleneterephthalate) film or a PC (polycarbonate) film.

6. The optical device according to claim 1, wherein the liquid crystal layer comprises a dichroic dye guest.

7. The optical device according to claim 1, wherein the liquid crystal element comprises a conductive layer formed on each of the first base layer and the second base layer.

8. The optical device according to claim 7, wherein the liquid crystal element comprises an alignment film formed on the conductive layer.

9. The optical device according to claim 1, wherein the liquid crystal element is capable of switching between first and second oriented states.

10. The optical device according to claim 1, further comprising a polarizer positioned between the first and second outer substrates.

11. The optical device according to claim 10, wherein the adhesive film is positioned between the first outer substrate and the liquid crystal element, between the liquid crystal element and the polarizer, and between the second outer substrate and the polarizer.

12. An automobile comprising a body on which one or more openings are formed; and the optical device of claim 1 mounted on the openings.

13. The optical device according to claim 10, wherein the adhesive film encapsulates the polarizer.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIGS. 1 to 2 are exemplary cross-sectional views of liquid crystal elements that can be used in an optical device of the present application.

(2) FIGS. 3 to 5 are exemplary cross-sectional views showing exemplary optical devices of the present application.

(3) FIGS. 6 to 8 are images photographed by using a digital camera after applying optical devices manufactured according to Example 1, Example 2 and Comparative Example to a high temperature long-term durability test.

DETAILED DESCRIPTION

(4) Hereinafter, the present application will be described in detail through Examples and Comparative Examples, but the scope of the present application is not limited by the following Examples.

(5) Method of Measuring Appearance Defects

(6) Appearance defects were measured in a state where the liquid crystal elements manufactured in Example 1, Example 2 and Comparative Example were encapsulated between the first and second outer substrates after an autoclave process. When the liquid crystal element encapsulated between the first and second outer substrates was applied to a high temperature long-term durability test (maintained at a temperature of 100° C. for about 168 hours) and left at room temperature for 24 hours or more, the appearance defects of the optical device were measured by confirming whether or not wrinkles were generated on the appearance of the optical device.

Example 1

(7) Liquid Crystal Element

(8) As the first and second base layers, a polycarbonate film (thickness: 300 μm, manufacturer: Keiwa Corporation) having a flexural rigidity (D) of about 5.73*10.sup.−3 N.Math.m was used, and ITO (indium-tin-oxide) was deposited to a thickness of 200 nm on each of the first base layer and the second base layer to form a conductive layer. A horizontal alignment film (SE-7492, Nissan Chemical Co., Ltd.) was coated to a thickness of 100 to 300 nm on the conductive layer and cured to form first and second alignment films.

(9) [98] A sealant was applied to the outer circumference of the first alignment film, a liquid crystal (MDA 14-4145, manufactured by Merck) was applied to the inner region of the sealant, and the second alignment film was laminated to manufacture a liquid crystal element. The area of the manufactured liquid crystal element is 600 mm×300 mm, and the cell gap is 12 μm.

(10) Optical Device

(11) A first outer substrate, an adhesive film, the liquid crystal element, an adhesive film, a polarizer, an adhesive film and a second outer substrate were laminated in this order, and the adhesive film was also disposed on all sides of the liquid crystal element to produce a laminate (the second outer substrate was arranged in the gravity direction as compared to the first outer substrate).

(12) As the first and second outer substrates, glass substrates having a thickness of about 3 mm or so were used, where a substrate having a curvature radius of about 2,470R (first outer substrate) and a substrate having a curvature radius of about 2,400R (second outer substrate) were used. On the other hand, a thermoplastic polyurethane adhesive film (thickness: about 0.38 mm, manufacturer: Argotec, product name: ArgoFlex) was used as the adhesive film.

(13) The laminate was subjected to an autoclave process at a temperature of about 105° C. and a pressure of about 2 atm to produce an optical device.

Example 2

(14) A liquid crystal element and an optical device were produced in the same manner as in Example 1, except that as the first and second base layers of the liquid crystal element, a polyethylene terephthalate (thickness: 145 μm, manufacturer: SKC Company) film having a flexural rigidity (D) of about 8.17*10.sup.−4 N.Math.m or so was used.

Comparative Example

(15) A liquid crystal element and an optical device were produced in the same manner as in Example 1, except that as the first and second base layers of the liquid crystal element, a polycarbonate film (thickness: 100 μm, manufacturer: Keiwa Co., Ltd.) having a flexural rigidity (D) of about 2.12*10.sup.−4 N-m was used.

(16) FIGS. 6 to 8 are photographs of the optical device after the durability test, where FIG. 6 is a device photograph of Example 1, FIG. 7 is a device photograph of Example 2, and FIG. 8 is a device photograph of Comparative Example. It can be confirmed from the optical devices of Examples 1 and 2 that the optical devices have been manufactured stably without appearance defects such as wrinkles, and in contrast, it can be confirmed from the device of Comparative Example that appearance defects such as wrinkles have been generated.