阅读说明：本技术 液晶显示装置 (Liquid crystal display device having a plurality of pixel electrodes ) 是由 富樫泰之 于 2019-06-17 设计创作，主要内容包括：本发明提供了一种抑制弯曲时黑显示状态下的漏光的液晶显示装置。本发明的液晶显示装置依次包括：常黑显示方式的液晶面板、第一粘合剂层、支持基板,所述液晶面板朝向所述第一粘合剂层侧方向依次包括第一偏振板、液晶单元以及第二偏振板,所述液晶单元包括第一基板、与所述第一基板相对设置的第二基板、被夹持在所述第一基板以及所述第二基板中间的液晶层、以及设置在所述液晶层的周围并粘合所述第一基板以及所述第二基板的外边缘的第二粘合剂层,所述第一粘合剂层粘合所述第二偏振板以及所述支持基板的外边缘,所述第一粘合剂层的杨氏模量大于第二粘合剂层的杨氏模量。(The invention provides a liquid crystal display device which can restrain light leakage in a black display state when bending. The liquid crystal display device of the present invention comprises in order: the liquid crystal panel of a normally black display system includes, in order toward the first pressure-sensitive adhesive layer side, a first polarizing plate, a liquid crystal cell, and a second polarizing plate, the liquid crystal cell includes a first substrate, a second substrate provided opposite to the first substrate, a liquid crystal layer sandwiched between the first substrate and the second substrate, and a second pressure-sensitive adhesive layer provided around the liquid crystal layer and adhering outer edges of the first substrate and the second substrate, the first pressure-sensitive adhesive layer adheres outer edges of the second polarizing plate and the support substrate, and a Young's modulus of the first pressure-sensitive adhesive layer is larger than a Young's modulus of the second pressure-sensitive adhesive layer.)

1. A liquid crystal display device, comprising in order:

a normally black display mode liquid crystal panel;

a first adhesive layer; and

a support substrate for supporting the substrate, a plurality of substrates,

the liquid crystal panel has a first polarizing plate, a liquid crystal cell, and a second polarizing plate in this order toward the first adhesive layer side,

the liquid crystal cell includes a first substrate, a second substrate disposed opposite to the first substrate, a liquid crystal layer sandwiched between the first substrate and the second substrate, and a second adhesive layer disposed around the liquid crystal layer and adhering outer edges of the first substrate and the second substrate,

the first adhesive layer adheres the second polarizing plate and the outer edge of the support substrate,

the young's modulus of the first adhesive layer is greater than the young's modulus of the second adhesive layer.

2. The liquid crystal display device according to claim 1, wherein the first adhesive layer and the second adhesive layer are made of the same material as each other.

3. The liquid crystal display device according to claim 1 or 2, wherein the first adhesive layer and the second adhesive layer have the same width as each other.

4. The liquid crystal display device according to claim 1 or 2, wherein the first adhesive layer and the second adhesive layer have the same thickness as each other.

5. The liquid crystal display device according to claim 1 or 2, wherein the supporting substrate, the first substrate, and the second substrate are made of the same material as each other.

6. The liquid crystal display device according to claim 1 or 2, wherein the first substrate and the second substrate have the same thickness as each other.

7. The liquid crystal display device according to claim 6, wherein the supporting substrate, the first substrate, and the second substrate have the same thickness as each other.

Technical Field

The present invention relates to a liquid crystal display device.

Background

In recent years, liquid crystal display devices are used in various applications, and techniques for bending liquid crystal panels as components have been studied (for example, refer to documents 1 to 5).

Disclosure of Invention

Technical problem to be solved by the invention

However, the present inventors have found that when a liquid crystal panel of a normally black display system such as an IPS (In-Plane Switching) mode is bent, a light white display portion called light leakage appears In a black display state.

Fig. 5 is a schematic cross-sectional view showing a conventional liquid crystal panel. As shown in fig. 5, the liquid crystal panel 102 is a liquid crystal panel of a normally black display system (for example, IPS mode), and includes a first polarizing plate 110, a liquid crystal cell 120, and a second polarizing plate 130 in this order from the observation surface side to the back surface side.

The liquid crystal cell 120 includes a first substrate 121, a second substrate 122, a liquid crystal layer 123, and a sealing material 124. In the liquid crystal unit 120, the first substrate 121 is disposed on the first polarizing plate 110 side, and the second substrate 122 is disposed on the second polarizing plate 130 side, and is disposed opposite to the first substrate 121. The liquid crystal layer 123 is sandwiched between the first substrate 121 and the second substrate 122. The sealing material 124 is disposed around the liquid crystal layer 123 and adheres outer edges of the first substrate 121 and the second substrate 122.

When the liquid crystal panel 102 is not bent, if light emitted from the backlight is emitted from the second polarizing plate 130 side (back side), the liquid crystal layer 123 is in a black display state when no voltage is applied thereto. Specifically, first, the light emitted from the backlight is transmitted through the second polarizing plate 130, and is converted into linearly polarized light that vibrates in a direction parallel to the transmission axis of the second polarizing plate 130. Then, the linearly polarized light transmitted through the second polarizing plate 130 passes through the second substrate 122, the liquid crystal layer 123, and the first substrate 121 in this order, and is then blocked (absorbed) by the first polarizing plate 110 set so that the transmission axis is orthogonal to the second polarizing plate 130.

Fig. 6 is a schematic cross-sectional view illustrating a state in which the liquid crystal panel in fig. 5 is bent. As shown in fig. 6, when the thicknesses of the first substrate 121 and the second substrate 122 are the same with each other in the state where the liquid crystal panel 102 is bent, a tensile stress is generated in the first substrate 121 and a compressive stress is generated in the second substrate 122 with the liquid crystal layer 123 as a boundary (a position where the stress is zero). Therefore, a phase difference due to photoelasticity occurs in the first substrate 121 and the second substrate 122.

Fig. 7 is a perspective view showing a principle of display of the liquid crystal panel in fig. 6. Fig. 7 is different from fig. 6 in that the first polarizing plate 110, the first substrate 121, the liquid crystal layer 123, the second substrate 122, and the second polarizing plate 130 are not bent and separated for convenience of description.

As shown in fig. 7, the light L emitted from the backlight is transmitted through the second polarizing plate 130, and then converted into linearly polarized light M1 oscillating in a direction parallel to the transmission axis of the second polarizing plate 130. Then, when the linearly polarized light M1 transmitted through the second polarizing plate 130 transmits through the second substrate 122, it is converted into elliptically polarized light N1 by being given a phase difference due to a compressive stress at the time of bending. The elliptically polarized light N1 transmitted through the second substrate 122 is not light that vibrates in a direction parallel to the long axes of the liquid crystal molecules 160 in the liquid crystal layer 123 when no voltage is applied, and therefore when light transmits through the liquid crystal layer 123, the phase difference is amplified and converted into elliptically polarized light N2. Then, when the elliptically polarized light N2 that has passed through the liquid crystal layer 123 passes through the first substrate 121, it is converted into elliptically polarized light N3 by being given a phase difference due to a tensile stress at the time of bending. Therefore, in the elliptically polarized light N3 that transmits the first substrate 121, a component that vibrates in a direction parallel to the transmission axis of the first polarized light 110 transmits the first polarized plate 110 as the linearly polarized light M2, and as a result, is observed as light leakage.

The present inventors confirmed that such light leakage was observed in the vicinity of the corners of the black display screen. Fig. 8 is a photograph showing a black display screen when the liquid crystal panel in fig. 6 is viewed from the first polarizing plate side. In a state when the liquid crystal panel 102 is bent, as shown in fig. 8, light leakage Z is observed near four corners of the black display screen. The present inventors considered that the reason is as follows.

In the liquid crystal panel 102, outer edges (four sides) of the first substrate 121 and the second substrate 122 are bonded by the sealing material 124. Therefore, in a state where the liquid crystal panel 102 is bent, the second substrate 122 is subjected to compressive stress, and the vicinities of the four corners thereof are stretched by the sealing material 124. As a result, the direction of the compressive stress in the second substrate 122 is deviated from other regions near the four corners, and a large phase difference is generated near the four corners in accordance with the deviation amount. In addition, similarly, in the state where the liquid crystal panel 102 is bent, the direction of the tensile stress is deviated from other regions near the four corners, and a large phase difference is generated near the four corners in accordance with the deviation amount.

Fig. 9 is a simulation result showing a relationship between the leak light intensity and the direction of the compressive stress of the second substrate in the vicinity of the corner surrounded by the broken line in fig. 8. In fig. 9, the contour lines correspond to the intensity of light leakage, the arrows correspond to the direction of compressive stress, and the short-side direction corresponds to the direction of the transmission axis of the second polarizing plate 130. As shown in fig. 9, it was confirmed that the direction of the compressive stress in the second substrate 122 was deviated from other regions near the four corners. As a result, it was confirmed that the intensity of light leakage was increased at the four corners of the black display screen, and light leakage did not occur except near the four corners of the black display screen.

The light leakage intensity is related to the proportional relationship of the following formula (F).

"light leakage intensity". alpha. [ (C)²t⁴E²)×sin²(2(β-α))]/R²(F)

Alpha-azimuth of transmission axis of the second polarizing plate 130 (first polarizing plate 110)

Azimuth angle of compressive stress (tensile stress) generated on the second substrate 122 (first substrate 121)

C-photoelastic coefficient of the second substrate 122 (first substrate 121)

t thickness of the second substrate 122 (first substrate 121)

E Young's modulus of the second substrate 122 (first substrate 121)

R radius of curvature of second substrate 122 (first substrate 121)

According to the above formula (F), the closer to 45 DEG the beta-alpha, the higher the light leakage intensity. On the other hand, when β — α is 0 ° or 90 °, the leak light intensity is 0. These are also confirmed by the simulation results shown in fig. 9.

As described above, there has been a problem in the past that light leakage in a black display state when a liquid crystal panel of a normally black display system is bent is suppressed. However, for example, in the inventions described in patent documents 1 to 5, there is room for improvement in suppressing such light leakage in a black display state.

The present invention has been made in view of the above-described situation, and an object thereof is to provide a liquid crystal display device in which light leakage in a black display state at the time of bending is suppressed.

Means for solving the technical problem

(1) In one embodiment of the present invention, a liquid crystal display device includes a liquid crystal panel of a normally black display mode; a first adhesive layer; and a support substrate, wherein the liquid crystal panel has a first polarizing plate, a liquid crystal cell, and a second polarizing plate in this order toward the first adhesive layer side, the liquid crystal cell includes a first substrate, a second substrate provided to face the first substrate, a liquid crystal layer sandwiched between the first substrate and the second substrate, and a second adhesive layer provided around the liquid crystal layer and adhering outer edges of the first substrate and the second substrate, the first adhesive layer adheres outer edges of the second polarizing plate and the support substrate, and a young's modulus of the first adhesive layer is larger than a young's modulus of the second adhesive layer.

(2) Another embodiment of the present invention is directed to the liquid crystal display device according to embodiment (1), wherein the first adhesive layer and the second adhesive layer are made of the same material.

(3) Another embodiment of the present invention is a liquid crystal display device according to the embodiment (1) or (2), wherein the first adhesive layer and the second adhesive layer have the same width as each other.

(4) Another embodiment of the present invention is a liquid crystal display device according to any one of embodiments (1) to (3), wherein the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer have the same thickness.

(5) In another embodiment of the present invention, in addition to any one of the embodiments (1) to (4), the support substrate, the first substrate, and the second substrate are made of the same material.

(6) In another embodiment of the present invention, in any one of the embodiments (1) to (5), the first substrate and the second substrate have the same thickness.

(7) Another embodiment of the present invention is a liquid crystal display device as defined in embodiment (6), wherein the supporting substrate, the first substrate, and the second substrate have the same thickness.

Advantageous effects

The invention provides a liquid crystal display device capable of suppressing light leakage in a black display state at the time of bending.

Drawings

Fig. 1 is a schematic cross-sectional view illustrating a liquid crystal display device of an embodiment.

Fig. 2 is a schematic perspective view illustrating a liquid crystal display device of an embodiment.

Fig. 3 is a schematic cross-sectional view illustrating a state in which the liquid crystal display device in fig. 1 is bent.

Fig. 4 is a schematic cross-sectional view showing an example in which the liquid crystal display device of the embodiment is applied to a smartphone.

Fig. 5 is a schematic cross-sectional view showing a conventional liquid crystal panel.

Fig. 6 is a schematic cross-sectional view illustrating a state in which the liquid crystal panel in fig. 5 is bent.

Fig. 7 is a perspective view for explaining a display principle of the liquid crystal panel in fig. 6.

Fig. 8 is a photograph showing a black display screen when the liquid crystal panel in fig. 6 is viewed from the first polarizing plate side.

Fig. 9 is a simulation result showing the relationship between the leak light intensity and the direction of the compressive stress on the second substrate in the vicinity of the corner surrounded by the dotted line in fig. 8.

Detailed Description

Although the following embodiments are disclosed and the present invention is explained in more detail with reference to the drawings, the embodiments of the present invention are not limited to these embodiments. The respective configurations of the embodiments may be appropriately combined or modified within a range not departing from the gist of the present invention.

In the present specification, "X to Y" means "X or more and Y or less".