JP5791098B2 - Optical element - Google Patents

Description

  The present invention relates to an optical element that can bend a pair of substrates sandwiching a substance having an optical effect, such as a liquid crystal layer or an organic EL layer, and has durability.

  Liquid crystal display elements, EL elements, microcapsule elements, electropowder fluid elements, electrowetting elements, electrophoretic elements, and the like are known as optical elements that sandwich a substance having an optical effect. Such an optical element is used for, for example, a mobile phone, a PDA (Personal Digital Assistant), a public display, etc. A material in which a substance having an optical effect is sandwiched between glass substrates is generally used (Patent Document 1).

JP 2010-217234 A

  In recent years, attempts have been made to use a plastic film such as a polyimide film as a substrate in place of a conventional glass substrate for the purpose of weight reduction or flexibility. Further, as a method for manufacturing an optical element using such a flexible substrate, a roll-to-roll method has attracted attention from the viewpoint of improving manufacturing efficiency. In the roll-to-roll method, since the back substrate and the front substrate are bonded together and wound into a roll shape, the optical element is held with the curvature radius of the roll after bonding. Moreover, the optical element produced by this method is assumed to be used for making use of flexible bendability.

  In order to satisfy the above requirements, it is necessary to satisfy both the flexibility of the optical element itself and the durability against the destruction of the element such as peeling and floating of the substrate caused by bending.

  The problem to be solved by the present invention has been made in view of such a situation, and can be bent, and it is difficult to cause peeling between the substrates due to bending, and it is practically applied to the roll-to-roll method. It is an object of the present invention to provide an optical element that is less likely to be damaged by bending and twisting of the optical element even in the production process.

  In order to solve the problems and achieve the object, the inventions according to claims 1 to 5 are configured as follows.

For example, when a bendable optical element having a cell gap of 5 μm is bent, it is 0.05 × 10 ⁻³ (a pair of flexibility at a curvature radius of 100 mm) in the lateral direction on a pair of flexible substrates with a curvature radius of 100 mm. The difference between the lengths of the substrates having the distance / the length of the long side (bending direction) of the optical element) occurs. The stress can be estimated by multiplying this by the elastic modulus of the sealing material. The smaller the elastic modulus of the sealing material, the smaller the stress generated by bending. When the optical element is fixed in a bent state, it is clear that the smaller the stress caused by the bending, the lower the risk of element destruction.

  For example, Japanese Patent Laid-Open No. 2000-066220 discloses that the elastic modulus of a cured seal material at 125 ° C. is desirably 300 MPa to 2000 MPa. The reason why 2000 MPa or less is desirable is that the seal material is very hard and brittle. In the impact resistance test by dropping the liquid crystal element, it can be mentioned that a crack occurs between the sealing material and the glass substrate to cause peeling. However, in the present invention, since a flexible substrate is used instead of a glass substrate, there is no problem in the impact resistance test even at an elastic modulus of 2000 MPa or more.

  As a result of intensive studies by the inventors, it has been found that there is a combination of sealing materials suitable for bending an optical element using a flexible substrate.

That is, the present invention is a bendable optical element in which a substance having an optical effect is sandwiched between a pair of flexible substrates, and the first member that seals the substance having the optical effect between the pair of substrates. Are provided in a rectangular shape, and the short side of the rectangular shape is only the first sealing material, and the long side of the rectangular shape is sandwiched between the first sealing material and the second sealing material. is configured present, the elastic modulus of the rectangular short side seal, and the elastic modulus of the rectangular long side seal Ru Oh an optical element characterized in that the different configurations.

  With the above configuration, the present invention has the following effects.

In this invention, the first sealing material that seals the substance having an optical effect between the pair of substrates is provided in a rectangular shape, and the short side of the rectangular shape is only the first sealing material, and the long side of the rectangular shape Is configured so that the second sealant is sandwiched between the first sealant, and the elastic modulus of the rectangular short side seal and the elastic modulus of the long side seal of the rectangular shape are By adopting different configurations, it becomes easy to add a curvature in one direction of the optical element. In addition, peeling between the substrates due to bending is unlikely to occur, and the element is hardly broken due to bending or twisting of the optical element in production processes such as application to the roll-to-roll method.

It is the figure which looked at the optical element of 1st Embodiment in the display direction. It is sectional drawing which follows the II-II line | wire of FIG. It is sectional drawing which follows the III-III line of FIG. It is the figure which looked at the optical element of 2nd implementation in the display direction. It is sectional drawing which follows the VV line of FIG. It is sectional drawing which follows the VI-VI line of FIG. It is the figure which looked at the optical element of 3rd implementation in the display direction. It is sectional drawing which follows the VIII-VIII line of FIG. It is sectional drawing which follows the IX-IX line of FIG. It is a figure which shows the durability test result by the curvature fixation of the liquid crystal display element of Example 1 thru | or Example 3. It is a figure which shows the durability test result by the curvature fixed of the liquid crystal display element of Example 4 and Example 5. FIG. It is a figure which shows the durability test result by the curvature fixing of the liquid crystal display element of Example 6. FIG.

  Hereinafter, embodiments of the optical element of the present invention will be described. The embodiment of the present invention shows the most preferable mode of the present invention, and the present invention is not limited to this.

[First Embodiment]
The optical element 10 of this embodiment is a bendable element in which a substance having an optical effect is sandwiched between a pair of flexible substrates 3 and 4 as shown in FIGS. 1 is a view of the optical element viewed in the display direction, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. Between the pair of substrates 3 and 4, the sealing materials 1 and 5 having different elastic moduli for sealing substances having optical effects are provided.

In this embodiment, the sealing materials 1 and 5 having different elastic moduli are formed in a rectangular shape along the shapes of the substrates 3 and 4, and the optical element 10 is bent on the long side and not on the short side. Composed. That is, the pair of long-side sealing materials 5 are bent and the pair of short-side sealing materials 1 are not bent. The elastic modulus of the long-side sealing material 5 and the short-side sealing material 1 are configured. The elastic modulus is different.
Thus, along the bending direction of the optical element 10, that is, the sealing material 5 on the long side is easy to bend by placing a sealing material having a lower elastic modulus among the sealing materials having different elastic moduli. . This long side seal material 5 is parallel to the bending direction.

  Among the sealing materials having different elastic moduli, at least one of the elastic materials at room temperature after curing has a range of 1 GPa to 2000 GPa, and the sealing material 5 having a lower elastic modulus disposed on the long side is a room temperature after curing. The elastic modulus in the range of 1 MPa to 1000 MPa, the long side is easy to bend, and the short side is difficult to bend.

  As described above, the sealing materials 1 and 5 having different elastic modulus are provided between the pair of substrates 3 and 4 as a substance having an optical effect, and the elastic modulus is different along the bending direction of the optical element 10. By disposing the sealing material 5 having a lower elastic modulus among the sealing materials 1 and 5, it becomes easy to add a curvature in one direction of the optical element 10. In addition, peeling between the substrates 3 and 4 due to bending is unlikely to occur, and destruction of the element due to bending and twisting of the optical element 10 is unlikely to occur in practice and in the production process.

  In the manufacture of the optical element 10 of this embodiment, a pair of long-side sealing materials 5 are simultaneously applied to at least one substrate 4 of a pair of substrates, and a pair of short-side sealing materials 1 are simultaneously performed. A rectangular shape is formed in accordance with the shape of the substrate 4. The liquid crystal material 2 is injected into a region surrounded by the sealing materials 1 and 5 having different elastic moduli, the other substrate 3 is bonded to one substrate 4, and the liquid crystal material 2 is narrowed between the pair of substrates 3 and 4. Hold it.

  In this embodiment, the substance having an optical effect is the liquid crystal material 2, which is used as a liquid crystal display element, but is also used for an EL element, a microcapsule element, an electropowder fluid element, an electrowetting element, an electrophoretic element, and the like. Can do.

[Second Embodiment]
As shown in FIGS. 4 to 6, the optical element 10 of this embodiment is provided with sealing materials 1 and 5 having different elastic moduli for sealing substances having an optical effect between a pair of substrates 3 and 4. The structure is the same as that of the first embodiment, and the same reference numerals are given to omit the description. 4 is a view of the optical element as viewed in the display direction, FIG. 5 is a cross-sectional view taken along line VV in FIG. 4, and FIG. 6 is a cross-sectional view taken along line VI-VI in FIG.

  In this embodiment, the sealing material 1 is formed in a rectangular shape along the shapes of the substrates 3 and 4, the sealing material 5 having a different elastic modulus is provided on the outer side along the long side of the sealing material 1, and the long side Is configured so that the short side is not bent. In this embodiment, at least one of the sealing materials having different elastic moduli has an elastic modulus at room temperature after curing of 1 GPa to 2000 GPa, and the sealing material 5 having different elastic moduli is elastic at room temperature after curing. The rate is in the range of 1 MPa to 1000 MPa.

  In this embodiment, the sealing material 5 having a different elastic modulus is provided on the outer side along the long side of the sealing material 1, so that the sealing material 5 on the long side is a sealing material having a lower elastic modulus and is easily bent. It has become.

  In the manufacture of the optical element of this embodiment, the sealing material 1 for sealing a substance having an optical effect is drawn in a rectangular shape on the substrate 4 of at least one of the pair of substrates according to the shape of the substrate 4. After the sealing material 1 was drawn, the sealing material 5 was drawn in parallel on the pair of long sides.

[Third Embodiment]
As shown in FIGS. 7 to 9, the optical element 10 of this embodiment is provided with sealing materials 1 and 5 having different elastic moduli for sealing substances having an optical effect between a pair of substrates 3 and 4. The structure is the same as that of the first embodiment, and the same reference numerals are given to omit the description. 7 is a view of the optical element viewed in the display direction, FIG. 8 is a sectional view taken along line VIII-VIII in FIG. 7, and FIG. 9 is a sectional view taken along line IX-IX in FIG.

In this embodiment, the sealing material 5 is configured such that the short side is only the sealing material 1 and the long side is sandwiched between the sealing materials 1. By providing the sealing material 5 having different elastic modulus so as to overlap along the long side of the sealing material 1, the sealing materials 1 and 5 on the long side become a sealing material having a lower elastic modulus.

  In the manufacture of the optical element according to this embodiment, the sealing materials 1 and 5 are drawn first in a rectangular shape in accordance with the shape of the substrate 4. After the sealing material 1 is drawn, a pair of long sides is drawn. The sealing material 5 was drawn in parallel on the side. Then, the sealing material 1 was again drawn on the sealing material 1 and the sealing material 5 drawn earlier.

(Example 1 to Example 3)
<Manufacture of liquid crystal display elements>
Examples 1 to 3 will be described with reference to FIGS. 1 to 3. A transparent electrode or a connection terminal pattern made of ITO or the like is formed on the substrate 3 and the substrate 4 by sputtering and then patterned by photolithography. The substrate 4 is a polymer film excellent in heat resistance such as polysulfone or a polymer film reinforced with an inorganic material. On the surface of the transparent electrode, a polyimide alignment film or the like is formed in advance by a printing method and subjected to an alignment treatment. Further, spacers are formed on the substrate 4. The spacer is patterned by photolithography.

  Thereafter, an application tool such as a dispenser is applied to the sealing member 1 or 5 made of an ultraviolet curable resin, a resin curable by a combination of ultraviolet rays and heat, or a thermosetting resin such as an acrylic resin or an epoxy resin on the substrate 4. Is used to form a rectangular frame.

  Next, the liquid crystal material 2 is supplied to the substrate 4 by a dropping injection method. That is, the liquid crystal material 2 is dropped inside the rectangular frame-shaped sealing members 1 and 5 formed on the surface of the substrate 4.

  Thereafter, the substrate 3 was superposed under vacuum on the substrate 4 onto which the liquid crystal was dropped.

<Durability test result by fixing curvature of liquid crystal display element>
The sealing material in the short side direction is set to 1, and the sealing material in the long side direction is set to 5, and the bending is performed in the long side direction. The liquid crystal display element was pressed along a semicircular acrylic cylinder having a curvature radius of 100 mm, and the short side was fixed with a mending tape. The types and elastic modulus of the sealing material 1 and the sealing material 5 are shown in the table of FIG. The confirmed results are shown in the table of FIG. For the case where the seal was not peeled off, a new liquid crystal display element under the same conditions was subjected to a 60 ° C., 80% constant temperature and humidity test for 24 hours. Thereafter, the liquid crystal display element was observed by sandwiching it between two polarizing plates, and a display having a region where the alignment state of the liquid crystal was disturbed was determined to be defective. The results are shown in the table of FIG.

Example 4
A fourth embodiment will be described with reference to FIGS. It was produced in the same manner as in Example 1 except that the sealing material 1 and the sealing material 5 were allowed to coexist on the long side. The improvement by the constant temperature and humidity test was seen with respect to Example 1, and the effect with respect to seal peeling was confirmed compared with Example 2. The results are shown in the table of FIG.

(Example 5)
Example 5 is a case where C was used for the sealing material 1 and deteriorated with respect to seal peeling. The results are shown in the table of FIG.

(Example 6)
A sixth embodiment will be described with reference to FIGS. It was produced in the same manner as in Example 1 except that the sealing material 1 and the sealing material 5 were applied on the long side. The seal peeling was improved with respect to Example 4, and it was possible to achieve both flexibility with respect to bending and display reliability. The results are shown in the table of FIG.

  The present invention can be bent and is less likely to be peeled off between the substrates due to bending, and is practically applied to the optical element in the production process such as application to the roll-to-roll method. The present invention can be applied to an optical element that does not easily break.

1, 5 Seal material 2 Liquid crystal material 3, 4 Substrate 10 Optical element

Claims (2)

A bendable optical element in which a substance having an optical effect is sandwiched between a pair of flexible substrates;
A first sealing material for sealing the substance having the optical effect between the pair of substrates is provided in a rectangular shape,
The short side of the rectangular shape is only the first sealing material, and the long side of the rectangular shape is configured to exist such that the second sealing material is sandwiched between the first sealing material,
An optical element characterized in that an elastic modulus of the rectangular short-side seal is different from an elastic modulus of the rectangular long-side seal. The optical element according to claim 1, wherein the substance having an optical effect is liquid crystal.