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EP-4191329-B1 - LIGHT MODULATING DEVICE

EP4191329B1EP 4191329 B1EP4191329 B1EP 4191329B1EP-4191329-B1

Inventors

  • GIM, MIN JUN
  • OH, DONG HYUN
  • YOU, JUNG SUN
  • KIM, JIN HONG
  • KIM, JUNG WOON
  • SEO, HAN MIN

Dates

Publication Date
20260506
Application Date
20210727

Claims (13)

  1. An optical device, comprising: a first outer substrate; a second outer substrate; and a light modulating device disposed between the first and second outer substrates, wherein the light modulating device is encapsulated with an encapsulating agent between the first and second outer substrates, the light modulating device comprising: a light modulation film layer, wherein the light modulation film layer comprises: a first substrate (100); a second substrate (200), wherein each of the first and second substrates (100, 200) has a first surface and a second surface, wherein the first surfaces of the first and second substrates face each other; a liquid crystal layer (600), wherein the liquid crystal layer (600) is disposed between the first and second substrates (100, 200), wherein the liquid crystal layer (600) is capable of implementing twisted orientation, and wherein a K value of Equation 1 below is in a range of 0.15 to 0.4: K = Δn × p / t wherein, Δn is a refractive index anisotropy of the liquid crystal layer (600), p is a pitch in the twisted orientation, and t is a thickness of the liquid crystal layer (600); a pressure-sensitive adhesive layer or an adhesive layer (1001) formed on the first surface of the first substrate (100); and a liquid crystal alignment film (2001) formed on the first surface of the second substrate (200), wherein the pressure-sensitive adhesive layer or adhesive layer (1001) is a silicone pressure-sensitive adhesive layer or adhesive layer, and wherein the liquid crystal alignment film (2001) is a vertical alignment film.
  2. The optical device according to claim 1, wherein no liquid crystal alignment film is formed on the first substrate.
  3. The optical device according to claim 1, wherein the refractive index anisotropy, Δn, of the liquid crystal layer (600) is in a range of 0.01 to 0.5.
  4. The optical device according to claim 1, wherein the pitch, p, of the twisted orientation is in a range of 1µm to 100µm.
  5. The optical device according to claim 1, wherein the thickness, t, of the liquid crystal layer (600) is in a range of 0.5µm to 50µm.
  6. The optical device according to claim 1, wherein the ratio, t/p, of the thickness, t, of the liquid crystal layer (600) to the pitch, p, of the twisted orientation is less than 1.
  7. The optical device according to claim 1, wherein the liquid crystal layer (600), upon formation, is in an initial state that is a vertical orientation state, and wherein the liquid crystal layer (600) is capable of implementing twisted orientation when a voltage is applied.
  8. The optical device according to claim 1, wherein the liquid crystal layer (600) comprises a liquid crystal compound and a chiral dopant.
  9. The optical device according to claim 1, wherein the first or second substrate (100, 200) has an in-plane phase difference of 500 nm or more for light with a wavelength of 550 nm.
  10. The optical device according to claim 1, further comprising: a polarization layer (400) disposed on the second surface of the first or second substrate (100, 200).
  11. The optical device according to claim 1, further comprising a polarization layer (400) disposed on the second surface of the first or second substrate (100, 200), wherein the first or second substrate (100, 200) has an in-plane phase difference of 500 nm or more for light with a wavelength of 550 nm, wherein a small angle betweenthe slow axis of the respective first or second substrate (100, 200) and the absorption axis of the polarization layer (400) is in a range of 80 degrees to 100 degrees.
  12. The optical device according to claim 1, further comprising an optically anisotropic film disposed between the first or second substrate (100, 200) and the liquid crystal layer (600) and satisfying the following Equation 3: nz < ny wherein, ny is the refractive index of the optically anisotropic film for a wavelength of 550 nm in the fast axis direction, and nz is the refractive index of the optically anisotropic film for a wavelength of 550 nm in the thickness direction.
  13. A method for manufacturing an optical device, comprising: encapsulating the light modulating device of claim 1 between a first outer substrate and a second outer substrate through a pressurizing process using an encapsulating agent.

Description

[Technical Field] This application claims priority based on Korean Patent Application No. 10-2020-0093729 filed on July 28, 2020. The present application relates to an optical device comprising a light modulating device and a method for manufacturing an optical device. [Background Art] A light modulating device, in which a light modulation layer comprising a liquid crystal compound and the like is positioned between two substrates, is used for various applications. In order for the light modulating device to exhibit performance suitable for the intended use, it is important to control the orientation state of the liquid crystal compound between the substrates according to the purpose. In the case where the light modulation layer is a liquid crystal layer, for controlling the orientation (especially initial orientation) of the liquid crystal compound, a device to which the liquid crystal compound is applied forms alignment films on both of the two substrate surfaces facing each other. A technique for configuring an optical device by encapsulating a light modulating device with an encapsulating agent or the like is known, and a pressure is applied to the optical device in the encapsulation process (for example, Patent Document 1). As such, mostly, in the encapsulation processes, the pressure is applied to the light modulating device. Therefore, there is a problem that the optical characteristics of the light modulating device are changed to be different from the designed characteristics by the applied pressure or the positions of the substrates disposed opposite to each other are misaligned by the pressure, thereby also generating optical defects. The prior art relevant for the present invention is given by EP 4 187 314 A1, EP 3 617 782 A1 and KR 2020 0044473 A. Hereby, EP 3 617 782 A1 discloses a light modulation device which has improved mechanical and optical properties. [Prior Art Documents] [Patent Documents] (Patent Document 1) Korean Laid-Open Patent Publication No. 2018-0119517 [Disclosure] [Technical Problem] The present application provides an optical device or a manufacturing method thereof. The present application is intended to provide an optical device comprising a light modulating device that can stably maintain designed optical properties even after an encapsulation process in which a pressure is applied, such as an autoclave process, or a manufacturing method thereof. The present application is also intended to provide an optical device comprising a light modulating device, which can also stably maintain the orientation state of a light modulation layer while effectively securing adhesive force between upper and lower substrates, or a manufacturing method thereof [Technical Solution] In this specification, the term 'vertical, parallel, orthogonal, or horizontal' defining an angle and an angular numerical value mean 'substantially vertical, parallel, orthogonal, or horizontal' and the substantially numerical value of the angle within a range without impairing the desired effect. The vertical, parallel, orthogonal, or horizontal and the numerical range include errors such as manufacturing errors or deviations (variations). For example, the above cases may each include an error within about ±10 degrees, an error within about ±9 degrees, an error within about ±8 degrees, an error within about ±7 degrees, an error within about ±6 degrees, an error within about ±5 degrees, an error within about ±4 degrees, an error within about ±3 degrees, an error within about ±2 degrees, an error within about ±1 degree, an error within about ±0.8 degrees, an error within about ±0.6 degrees or an error within about ±0.4 degrees. Among physical properties mentioned in this specification, when the measured temperature affects relevant physical properties, the physical properties are physical properties measured at room temperature, unless otherwise specified. The term room temperature is a temperature in a state without particularly warming or cooling, which may mean one temperature in a range of about 10°C to 30°C, for example, a temperature of about 15°C or higher, 18°C or higher, 20°C or higher, or about 23°C or higher, and about 27°C or lower. Unless otherwise specified, the unit of the temperature mentioned herein is °C. The phase difference, refractive index and refractive index anisotropy mentioned in this specification means the phase difference, refractive index and refractive index anisotropy for light with a wavelength of about 550 nm, unless otherwise specified. Unless otherwise specified, the angle formed by any two directions, which is mentioned herein, may be an acute angle of acute angles to obtuse angles formed by the two directions, or may be a small angle from angles measured in clockwise and counterclockwise directions. Thus, unless otherwise specified, the angles mentioned herein are positive. However, in order to display the measurement direction between the angles measured in the clockwise dir