Search

JP-7856461-B2 - Laminates, optical components, and optical devices

JP7856461B2JP 7856461 B2JP7856461 B2JP 7856461B2JP-7856461-B2

Inventors

  • 濱田 千絵
  • 杉野 晶子
  • 吉見 俊哉

Assignees

  • 日東電工株式会社

Dates

Publication Date
20260511
Application Date
20220328

Claims (11)

  1. It includes a void layer and an adhesive layer, The adhesive layer is directly laminated on one or both sides of the void layer. The adhesive layer is formed from an adhesive comprising a (meth)acrylic polymer , an oligomer-type silane coupling agent , and a crosslinking agent . The (meth)acrylic polymer contains 1 to 30% by mass of nitrogen-containing monomers as monomer units. A laminate characterized in that the content of the oligomer-type silane coupling agent is 1 part by mass or less per 100 parts by mass of the (meth)acrylic polymer.
  2. The laminate according to claim 1, characterized in that the oligomeric silane coupling agent contains an epoxy group.
  3. The laminate according to claim 1 or 2, wherein the weight-average molecular weight (Mw) of the (meth)acrylic polymer is 1.5 million to 4 million.
  4. The laminate according to any one of claims 1 to 3, wherein the weight-average molecular weight (Mw) of the oligomer-type silane coupling agent is 300 or more.
  5. The adhesive is a laminate according to any one of claims 1 to 4, wherein the gel fraction exceeds 85%.
  6. The laminate according to any one of claims 1 to 5 , wherein the nitrogen-containing monomer is a heterocyclic acrylic monomer.
  7. The laminate according to any one of claims 1 to 6, characterized in that, before and after a heat durability test in which the temperature is maintained at 65°C and relative humidity at 95 % for 1000 hours, the increase in the refractive index of the void layer satisfies the following formula (1), and the initial refractive index before the heat durability test satisfies the following formula (2). n−n 0 ≦0.015 (1) n 0 <1.23 (2) In the above formula (1), n is the refractive index of the void layer after the heat endurance test. In the above formula (2), n 0 is the refractive index of the void layer before the heat endurance test.
  8. An intermediate layer exists between the aforementioned void layer and the aforementioned adhesive layer. The laminate according to any one of claims 1 to 7 , wherein the intermediate layer is a layer formed by the union of the void layer and the adhesive layer.
  9. The laminate according to claim 8 , wherein the thickness of the intermediate layer is 10 to 100 nm.
  10. An optical member characterized by comprising a laminate according to any one of claims 1 to 9 .
  11. An optical device characterized by including the optical member described in claim 10 .

Description

This invention relates to laminates, optical components, and optical devices. In optical devices, for example, an air layer with a low refractive index is used as a total internal reflection layer. Specifically, in liquid crystal devices, for example, each optical film component (e.g., a light guide plate and a reflector plate) is laminated with an air layer in between. However, when components are separated by an air layer, problems such as component deflection may occur, especially when the components are large. Furthermore, with the trend towards thinner devices, integration of each component is desired. Therefore, methods are employed to integrate each component with adhesive without an air layer (for example, Patent Document 1). However, the absence of the air layer that plays a role in total internal reflection may lead to a decrease in optical properties, such as light leakage. Therefore, it has been proposed to use a low refractive index layer instead of an air layer. For example, Patent Document 2 describes a structure in which a layer with a lower refractive index than the light guide plate is inserted between the light guide plate and the reflector plate. As the low refractive index layer, for example, a void layer with air gaps is used to achieve a refractive index as close as possible to that of air. Furthermore, an integrated configuration with an adhesive layer has been proposed to introduce the void layer into the device (Patent Document 3). Japanese Patent Publication No. 2012-156082Japanese Patent Application Publication No. 10-62626Japanese Patent Publication No. 2014-46518 Figures 1(a) and 1(b) are cross-sectional views illustrating the structure of the laminate according to the present invention.Figures 2(a) and 2(b) are cross-sectional views showing another example of the configuration of the laminate according to the present invention.Figures 3(a) and 3(b) are cross-sectional views showing yet another example of the configuration of the laminate according to the present invention. Next, the present invention will be described in more detail with examples. However, the present invention is not limited in any way by the following description. The laminate of the present invention may, for example, contain an epoxy group in the oligomer-type silane coupling agent. The laminate of the present invention may, for example, have a weight-average molecular weight (Mw) of the (meth)acrylic polymer of 1.5 million to 4 million. The laminate of the present invention may, for example, have a weight-average molecular weight (Mw) of 300 or more of the oligomer-type silane coupling agent. The laminate of the present invention, for example, is formed by an adhesive adhesive comprising the (meth)acrylic polymer and a crosslinking agent in the adhesive layer, and the gel fraction of the adhesive may exceed 85%. The laminate of the present invention may, for example, contain 1 to 30% by mass of nitrogen-containing monomers as monomer units in the (meth)acrylic polymer. In this invention, unless otherwise specified, "mass%" and "weight%" may be interpreted as interchangeable, and "parts by mass" and "parts by weight" may be interpreted as interchangeable. The laminate of the present invention may, for example, satisfy the following formula (1) when the increase in refractive index of the void layer before and after a heat durability test in which it is held at a temperature of 65°C and a relative humidity of 95% for 1000 hours, and the following formula (2) when the initial refractive index before the heat durability test is satisfied. n−n 0 ≦0.015 (1) n 0 <1.23 (2) In the above formula (1), n is the refractive index of the void layer after the heat endurance test. In the above formula (2), n 0 is the refractive index of the void layer before the heat endurance test. The laminate of the present invention may, for example, have an intermediate layer between the void layer and the adhesive layer, and the intermediate layer may be a layer formed by the fusion of the void layer and the adhesive layer. The laminate of the present invention may, for example, have an intermediate layer with a thickness of 10 to 100 nm. In this invention, the term "adhesive layer" refers to a layer formed by at least one of an adhesive and a bonding agent. Unless otherwise specified, the "adhesive layer" may be an "adhesive layer" formed by an adhesive, an "adhesive layer" formed by a bonding agent, or a layer containing both an adhesive and a bonding agent. Furthermore, in this invention, adhesives and bonding agents are sometimes collectively referred to as "adhesive bonding agents." Generally, agents with relatively weak adhesive strength (e.g., agents that allow for re-peeling of the bonded object) are called "adhesives," while agents with relatively strong adhesive strength (e.g., agents that make re-peeling of the bonded object impossible or extremely difficult) are sometimes called "bonding agents." In this invention, there