WO2023038053A1

WO2023038053A1 - Liquid crystal display device

Info

Publication number: WO2023038053A1
Application number: PCT/JP2022/033527
Authority: WO
Inventors: 若彦金子; 之人齊藤
Original assignee: 富士フイルム株式会社
Priority date: 2021-09-10
Filing date: 2022-09-07
Publication date: 2023-03-16
Also published as: CN117916656A; JPWO2023038053A1

Abstract

The purpose of the present invention is to provide a semi-transmissive liquid crystal display device which has high light utilization efficiency and in which the difference in color gamut between a reflective mode and a transmissive mode is small, and contrast is high in external light. This liquid crystal display device includes a backlight unit (101) and a liquid crystal panel (105), the liquid crystal panel (105) including a first polarizer (151), a liquid crystal layer (180), and a second polarizer (152) in the stated order from the backlight unit (101) side, and the liquid crystal display device furthermore having, between the backlight unit (101) and the liquid crystal panel (105), a light-emitting layer (131) that emits light as a result of being excited by light emitted from the backlight unit (101), and also emits light as a result of being excited by external light incident from outside the liquid crystal display device, and having a λ/4 phase difference layer (141) between the first polarizer (151) and the light-emitting layer (131).

Description

liquid crystal display

The present invention relates to a liquid crystal display device.

A liquid crystal display device has red, green, and blue light-emitting layers (color conversion layers and wavelength conversion layers), and external light excites the red, green, and blue light-emitting layers to emit light, thereby displaying an image. Disclosed is a transflective liquid crystal display device having a reflective mode for displaying and a transmissive mode for displaying an image by exciting light-emitting layers of red, green, and blue to emit light using a backlight unit as an excitation light source. there is A transflective liquid crystal display device displays an image in a bright place by exciting the light-emitting layer mainly by external light, and displays an image in a dark place by exciting the light-emitting layer mainly by a backlight unit. can be done.

For example, Patent Document 1 discloses a wavelength conversion layer that receives external light incident from the viewing side and outputs wavelength-converted light, a liquid crystal layer that is disposed on the viewing side of the wavelength conversion layer, and a wavelength conversion layer. a polarizing layer disposed between the layer and the liquid crystal layer; and a reflective layer disposed on the opposite side of the wavelength conversion layer from the viewing side and reflecting the light from the wavelength conversion layer. This document describes a liquid crystal display device in which the light passes through the polarizing layer and the liquid crystal layer and is emitted to the viewing side, and that a backlight is provided on the side opposite to the viewing side of the transmissive portion.

Japanese Patent Application Laid-Open No. 2020-109425

Since the surface of the light-emitting layer has the property of reflecting part of the light, there was a problem that outside light would be reflected on the surface of the light-emitting layer, especially outdoors, and the contrast would not be high.

In addition, in the transflective liquid crystal display device as described in Patent Document 1, there is a problem that the appearance differs due to the difference in color gamut between the reflective mode and the transmissive mode. Specifically, as described above, external light is reflected on the surface of the light-emitting layer, so the ratio of RGB of light emitted from the liquid crystal display device changes depending on the brightness of the surroundings. Therefore, a difference occurs in the color gamut between the reflective mode and the transmissive mode.

An object of the present invention is to solve such problems, and to provide a semi-transmissive liquid crystal display device which has a small difference in color gamut between the reflection mode and the transmission mode and has high contrast even under external light. It is in.

The present invention solves the problem with the following configuration.

[1] A liquid crystal display device including a backlight unit and a liquid crystal panel,
the liquid crystal panel includes, from the backlight side, a first polarizer, a liquid crystal cell, and a second polarizer;
Between the backlight unit and the liquid crystal cell, there is further provided a light-emitting layer that emits light when excited by light emitted from the backlight unit and also excited by external light incident from the outside of the liquid crystal display device to emit light. ,
Having a λ / 4 retardation layer between the first polarizer and the light emitting layer,
A liquid crystal display device having a visible light reflecting layer between a light emitting layer and a backlight unit.
[2] The liquid crystal display according to [1], which has a color absorption layer that absorbs light in at least a part of the wavelength range other than the wavelength emitted by the light-emitting layer and the excitation wavelength of the light-emitting layer, on the viewing side of the light-emitting layer. Device.
[3] The liquid crystal display device according to [1] or [2], wherein the backlight unit emits light having a wavelength that excites the light-emitting layer.
[4] The liquid crystal display device according to any one of [1] to [3], wherein the light-emitting layer contains a phosphor.
[5] The light-emitting layer has a red light-emitting region that excites and emits red light, a green light-emitting region that excites and emits green light, and a blue light-emitting region that excites and emits blue light, [1] to [4] The liquid crystal display device according to any one of 1.

According to the present invention, it is possible to provide a transflective liquid crystal display device that has high light utilization efficiency, a small difference in color gamut between reflection mode and transmission mode, and high contrast even under external light.

It is a figure which shows notionally an example of a structure of the liquid crystal display device of this invention. 2 is a diagram for explaining the operation of the liquid crystal display device shown in FIG. 1 in a reflective mode; FIG. 2 is a diagram for explaining the operation of the liquid crystal display device shown in FIG. 1 in a transmission mode; FIG. FIG. 4 is a diagram conceptually showing another example of the liquid crystal display device of the present invention; It is a graph showing the relationship between wavelength and transmittance. It is a graph showing the relationship between wavelength and intensity of fluorescence. It is a graph showing the relationship between wavelength and luminance. 2 is a diagram conceptually showing the configuration of a liquid crystal display device of Comparative Example 1. FIG. 3 is a diagram conceptually showing the configuration of a liquid crystal display device of Comparative Example 2. FIG.

The present invention will be described in detail below. In this specification, the numerical range represented by "-" means a range including the numerical values before and after "-" as lower and upper limits.
Further, in this specification, "(meth)acrylate" is a notation representing both acrylate and methacrylate, and "(meth)acryloyl group" is a notation representing both an acryloyl group and a methacryloyl group, "(Meth)acrylic" is a notation representing both acrylic and methacrylic.
In this specification, terms such as "same" and "same" shall include the margin of error generally accepted in the technical field. In this specification, terms such as "same" and "same" with respect to angles mean that the difference from the exact angle is within a range of less than 5 degrees, unless otherwise specified. The difference from the exact angle is preferably less than 4 degrees, more preferably less than 3 degrees.

[Liquid crystal display device]
The liquid crystal display device of the present invention is
A liquid crystal display device including a backlight unit and a liquid crystal panel,
the liquid crystal panel includes, from the backlight side, a first polarizer, a liquid crystal cell, and a second polarizer;
Between the backlight unit and the liquid crystal cell, there is further provided a light-emitting layer that emits light when excited by light emitted from the backlight unit and also excited by external light incident from the outside of the liquid crystal display device to emit light. ,
Having a λ / 4 retardation layer between the first polarizer and the light emitting layer,
The liquid crystal display device has a visible light reflecting layer between the light emitting layer and the backlight unit.
Embodiments of the liquid crystal display device of the present invention will be described below with reference to the drawings.

FIG. 1 shows a diagram conceptually showing an example of the configuration of the liquid crystal display device of the present invention.
The liquid crystal display device 100 shown in FIG. 1 includes a backlight unit 101, a glass substrate 111, a visible light reflecting layer 121, a red light emitting region 131R, a green light emitting region 131G and a blue light emitting region 131R, which are separated by partition walls 132 and arranged in the plane direction. A light-emitting layer 131 having a light-emitting region 131B, a λ/4 retardation layer 141, a first polarizer 151, a barrier layer 190, a transparent electrode 161, an alignment film 171, a liquid crystal layer 180, and an alignment film 172. ,

transparent electrodes

162R, 162G and 162B arranged in the plane direction separated by a black matrix 192, the glass substrate 112, and the second polarizer 152 in this order.

In the example shown in FIG. 1, the laminate from the first polarizer 151 to the second polarizer 152 including the liquid crystal layer 180 is the liquid crystal panel 105 of the present invention. Also, the laminate from the glass substrate 112 to the barrier layer 190 is the liquid crystal cell 106 in the present invention.

As shown in FIG. 1, the liquid crystal display device 100 of the present invention has a light-emitting layer 131 between the backlight unit 101 and the liquid crystal panel 105 . Further, a λ/4 retardation layer 141 is provided between the first polarizer 151 and the light emitting layer 131 .

In addition, the liquid crystal display device 100 shown in FIG. 1 has the visible light reflecting layer 121 between the light emitting layer 131 and the backlight unit 101 as a preferred embodiment. The visible light reflecting layer 121 reflects at least the wavelength of the light emitted by the light emitting layer 131 and transmits the light of the wavelength of the excitation light that excites the light emitting layer 131 .

The operation of such a liquid crystal display device 100 will be described with reference to FIGS. 2 and 3. FIG.
2A and 2B are diagrams for explaining the action of the liquid crystal display device 100 in the reflective mode, and FIGS. 3A and 3B are diagrams for explaining the action of the liquid crystal display device 100 in the transmissive mode. 2 and 3, illustration of some members is omitted for explanation.

FIG. 2 shows a portion corresponding to a certain pixel of the liquid crystal display device 100. In the figure, the light emitting layer 131 includes only one of red light emitting region 131R, green light emitting region 131G and blue light emitting region 131B. is shown. FIG. 2 is a diagram for explaining the case where this pixel is lit.

As shown in FIG. 2, in the reflective mode, the liquid crystal display device 100 does not turn on the backlight unit and uses external light _I0 to display an image. Specifically, as indicated by the row of arrows in the middle of FIG. 2, external light I ₀ enters the liquid crystal display device 100 from the second polarizer 152 side, which is the viewing side. Since the incident external light is basically unpolarized, it is converted into linearly polarized light in the transmission axis direction of the second polarizer 152 by passing through the second polarizer 152 . The light converted to linearly polarized light passes through liquid crystal cell 106 . The liquid crystal cell 106 changes the alignment state of liquid crystal molecules by applying a voltage to the liquid crystal layer 180, thereby rotating the polarization direction of linearly polarized light and transmitting it. In the illustrated example, when the corresponding pixel is lit, the liquid crystal cell 106 rotates the polarization direction of the linearly polarized light by 90° and transmits the light.

The linearly polarized light that has passed through the liquid crystal cell 106 enters the first polarizer 151 . The transmission axis of the first polarizer 151 is orthogonal to the transmission axis of the second polarizer 152 . Since the polarization direction of the linearly polarized light transmitted through the second polarizer 152 is rotated by 90° by the liquid crystal cell 106 , the linearly polarized light incident on the first polarizer 151 is transmitted through the first polarizer 151 . The linearly polarized light transmitted through the first polarizer 151 enters the λ/4 retardation layer 141 .

The λ/4 retardation layer 141 converts linearly polarized light transmitted through the first polarizer 151 into circularly polarized light. In the illustrated example, as an example, conversion into clockwise circularly polarized light (right circularly polarized light) will be described. The right-handed circularly polarized light converted by the λ/4 retardation layer 141 enters the light-emitting layer 131 .

The circularly polarized light incident on the light-emitting layer 131 includes a wavelength that excites the light-emitting layer 131 , such as ultraviolet (UV) light, and excites the light-emitting layer 131 . This causes the light emitting layer 131 to emit light I ₁ . The light I ₁ emitted by the light emitting layer 131 has no directivity and travels in various directions. Also, the emitted light _I1 is unpolarized. Of the light I ₁ emitted by the light emitting layer 131 , the light emitted toward the viewing side enters the λ/4 retardation layer 141 as it is. Further, the light emitted toward the backlight unit 101 enters the visible light reflecting layer 121 arranged between the light emitting layer 131 and the backlight unit 101, and is reflected toward the viewing side. By having the visible light reflecting layer 121, the utilization efficiency of the light I ₁ emitted by the light emitting layer 131 can be improved.

As indicated by the row of arrows on the right side of FIG. 2, the light I ₁ emitted from the light-emitting layer 131 enters the λ/4 retardation layer 141 either directly or after being reflected by the visible light reflecting layer 121 . Since the light I ₁ is non-polarized, the light I ₁ passes through the λ/4 retardation layer 141 while remaining non-polarized. The light I ₁ that has passed through the λ/4 retardation layer 141 enters the first polarizer 151 and is converted into linearly polarized light. The light converted to linearly polarized light passes through liquid crystal cell 106 . The liquid crystal cell 106 rotates the polarization direction of the linearly polarized light by 90° and transmits it. The linearly polarized light that has passed through the liquid crystal cell 106 enters the second polarizer 152 . Since the transmission axis of the second polarizer 152 is orthogonal to the transmission axis of the first polarizer 151 , the linearly polarized light I ₂ whose polarization direction is rotated 90° by the liquid crystal cell 106 is transmitted through the second polarizer 152 . and emitted from the liquid crystal display device 100 .

In FIG. 2, the case of turning on the pixels has been described. Make it transparent without rotating. As a result, the linearly polarized light converted by the external light I ₀ passing through the second polarizer 152 passes through the liquid crystal cell 106 while maintaining the polarization direction, and enters the first polarizer 151. This linearly polarized light is not transmitted because its polarization direction is orthogonal to the transmission axis of the first polarizer 151 . Therefore, light does not reach the light-emitting layer 131 and does not emit light, so this pixel does not light up. Alternatively, since the first polarizer 151, the second polarizer 152, and the λ/4 retardation layer 141 are optimized for visible light, these layers are Since it does not act sufficiently and the polarization state is not properly converted, the excitation light may reach the light-emitting layer 131 without being blocked, but the light emitted by the light-emitting layer 131 is The light is converted into linearly polarized light by , passes through the liquid crystal cell 106 while maintaining the polarization direction, enters the second polarizer 152 , and is blocked. Therefore, the light emitted by the light emitting layer 131 is not emitted from the liquid crystal display device 100, and this pixel does not light up.

The liquid crystal display device 100 can display an image by turning on or off each pixel with the liquid crystal cell 106 .

Here, since the surface of the light-emitting layer 131 has the property of reflecting light, part of the external light is reflected on the surface of the light-emitting layer 131 . Since light in the visible light region is reflected on the surface of the light-emitting layer 131, when the light reflected by the surface of the light-emitting layer 131 is emitted from the viewing side of the liquid crystal display device 100, the difference in brightness and color between pixels is increased. The difference becomes small and the contrast is lowered.

On the other hand, the liquid crystal display device 100 of the present invention has the λ/4 retardation layer 141 between the first polarizer 151 and the light emitting layer 131 . As a result, it is possible to suppress the light reflected by the surface of the light-emitting layer 131 from being emitted from the liquid crystal display device 100, thereby suppressing a decrease in contrast.

Specifically, as shown in FIG. 2, external light I ₀ incident on the liquid crystal display device 100 is transmitted through the λ/4 retardation layer 141 and converted into circularly polarized light when incident on the light emitting layer 131. . Therefore, as indicated by the row of arrows on the left side of FIG. 2, the circularly polarized light reflected by the surface of the light emitting layer 131 is converted into circularly polarized light in the opposite direction of rotation. In the illustrated example, it is left-handed circularly polarized light. This left-handed circularly polarized light enters the λ/4 retardation layer 141 and is converted into linearly polarized light, which is converted into linearly polarized light in a direction orthogonal to the polarization direction of the linearly polarized light before being reflected. That is, the left-handed circularly polarized light is converted into linearly polarized light with a polarization direction perpendicular to the transmission axis of the first polarizer 151 . Therefore, this linearly polarized light does not pass through the first polarizer 151 and is shielded. Thereby, it is possible to suppress the light reflected by the surface of the light emitting layer 131 from being emitted from the liquid crystal display device 100 .

Next, the operation of the liquid crystal display device 100 in the transmissive mode will be described with reference to FIG.

In the transmissive mode, the backlight unit 101 lights up and emits light _I3 having a wavelength that excites the light-emitting layer 131, eg, ultraviolet (UV). Of the light I ₃ emitted from the backlight unit 101 , at least light having an excitation wavelength such as ultraviolet (UV) passes through the visible light reflecting layer 121 and enters the light emitting layer 131 . This causes the light-emitting layer 131 to emit light I ₄ . As in the example shown in FIG. 2, the light I ₄ emitted by the light-emitting layer 131 enters the λ/4 retardation layer 141 either directly or after being reflected by the visible light reflecting layer 121 . Since the light I ₁ is unpolarized, the light I ₄ passes through the λ/4 retardation layer 141 while remaining unpolarized. The light I ₄ that has passed through the λ/4 retardation layer 141 enters the first polarizer 151 and is converted into linearly polarized light. The light converted to linearly polarized light passes through liquid crystal cell 106 . The liquid crystal cell 106 rotates the polarization direction of the linearly polarized light by 90° and transmits it. The linearly polarized light that has passed through the liquid crystal cell 106 enters the second polarizer 152 . Since the transmission axis of the second polarizer 152 is orthogonal to the transmission axis of the first polarizer 151 , the linearly polarized light I ₅ whose polarization direction is rotated 90° by the liquid crystal cell 106 is transmitted through the second polarizer 152 . and emitted from the liquid crystal display device 100 .

As in the case of the reflection mode, by switching the voltage application state to the liquid crystal cell 106, each pixel can be lit or extinguished to display an image.

Here, in the case of the transmission mode, if external light is present, the effects of the reflection mode shown in FIG. 2 are also superimposed. That is, the light-emitting layer 131 is excited by both external light and light from the backlight unit to emit light.

When there is external light, part of the external light is reflected on the surface of the light emitting layer 131, as in the case of the reflection mode described above. If the λ/4 retardation layer 141 is not provided, the light reflected by the surface of the light-emitting layer 131 is emitted from the liquid crystal display device 100, resulting in a decrease in contrast, as in the case of the reflective mode. do. Moreover, in the transmissive mode, the light-emitting layer 131 is excited by both the outside light and the light from the backlight unit, so the amount of light emitted from the light-emitting layer 131 is greater than in the reflective mode. Therefore, the ratio of the light emitted by the light-emitting layer and the light reflected by the surface of the light-emitting layer is different from that in the reflection mode. As a result, there arises a problem that a color gamut difference occurs between the reflective mode and the transmissive mode.

On the other hand, the liquid crystal display device 100 of the present invention has the λ/4 retardation layer 141 between the first polarizer 151 and the light emitting layer 131 . Accordingly, even in the transmissive mode, it is possible to suppress the light reflected by the surface of the light emitting layer 131 from being emitted from the liquid crystal display device 100, thereby suppressing a decrease in contrast. In addition, since the light reflected by the surface of the light-emitting layer 131 can be suppressed from being emitted from the liquid crystal display device 100, the light emitted by the light-emitting layer and the light reflected by the surface of the light-emitting layer can be suppressed in the reflection mode and the transmission mode. The difference in ratio to light is reduced, and the difference in color gamut between the reflective mode and the transmissive mode can be reduced.

Note that in the example shown in FIG. 1, the visible light reflecting layer 121 is provided between the light-emitting layer 131 and the backlight unit 101 as a preferred embodiment, but the liquid crystal display device of the present invention includes the visible light reflecting layer 121. You don't have to. As described above, by having the visible light reflecting layer 121, the utilization efficiency of the light emitted by the light emitting layer 131 can be improved.

Further, the liquid crystal display device of the present invention may have a color absorption layer between the second polarizer and the light emitting layer that absorbs light in at least part of the wavelength range other than the wavelength emitted by the light emitting layer. .
FIG. 4 shows a conceptual diagram of another example of the liquid crystal display device of the present invention.

The liquid crystal display device 200 shown in FIG. 4 includes a backlight unit 201, a glass substrate 211, a visible light reflecting layer 221, a red light emitting region 231R, a green light emitting region 231G and a blue light emitting region 231R, which are separated by partition walls 232 and arranged in the plane direction. A light-emitting layer 231 having a light-emitting region 231B, a λ/4 retardation layer 241, a first polarizer 251, a barrier layer 290, a transparent electrode 261, an alignment film 271, a liquid crystal layer 280, and an alignment film 272. ,

transparent electrodes

262R, 262G and 262B arranged in the plane direction separated by a black matrix 292, a glass substrate 212, a color absorption layer 242, and a second polarizer 252 in this order.

The liquid crystal display device 200 shown in FIG. 4 has the same configuration as that of the liquid crystal display device 100 shown in FIG.

The color absorption layer 242 absorbs light in at least part of the wavelength range other than the wavelength emitted by the light emitting layer 231 and the excitation wavelength of the light emitting layer 231 . As shown in FIG. 6, which is a graph of the emission intensity of the light-emitting layer in Examples described later, the phosphor used as the light-emitting layer 231 often emits light with a sharp peak. Therefore, by arranging the color absorption layer 242 that absorbs light in a wavelength range other than the peak wavelength and light in a wavelength range other than the excitation wavelength of the light emitting layer 231 between the light emitting layer 231 and the second polarizer 252, Of the external light reflected on the surface of the light-emitting layer 231 , light having a wavelength other than the wavelength emitted by the light-emitting layer 231 can be absorbed and prevented from being emitted from the liquid crystal display device 200 . This makes it possible to further suppress a decrease in contrast and further reduce the difference in color gamut between the reflective mode and the transmissive mode.

In addition, since the color absorption layer 242 does not absorb the light of the wavelength emitted by the light emitting layer 231 , the excitation wavelength component of the external light incident from the second polarizer 252 side can be transmitted and made incident on the light emitting layer 231 . , and the light-emitting layer 231 can be properly excited to emit light.

Here, in the example shown in FIG. 4, the color absorption layer 242 is arranged between the second polarizer 252 and the glass substrate 212, but the configuration is not limited to this. The color absorption layer 242 may be arranged on the viewer side from the light emitting layer 231, for example, it may be between the light emitting layer 231 and the λ/4 retardation layer 241, or the λ/4 retardation layer 241 and the first polarizer 251 .
The protective film of the polarizer 252 may be used as a color absorption layer because the thickness can be made thinner.

The constituent elements of the liquid crystal display device of the present invention will be described below.

<Polarizer>
The first polarizer and the second polarizer are linear polarizers, have unidirectional polarization axes, and have the function of transmitting specific linearly polarized light.
As the linear polarizer, a general linear polarizer such as an absorption polarizer containing an iodine compound and a reflective polarizer such as a wire grid can be used. The polarization axis is synonymous with the transmission axis.
As the absorbing polarizing plate, for example, any of an iodine polarizing plate, a dye polarizing plate using a dichroic dye, and a polyene polarizing plate can be used. Iodine-based polarizing plates and dye-based polarizing plates are generally produced by allowing polyvinyl alcohol to adsorb iodine or a dichroic dye and stretching the resultant.

<Liquid crystal cell>
A well-known liquid crystal cell can be mentioned as a liquid crystal cell. The drive mode of the liquid crystal cell is not particularly limited, and specific examples include IPS (In Plane Switching) mode, FFS (Fringe Field Switching) mode, VA (Vertical Alignment) mode, TN (Twisted Nematic) mode, and the like. mode can be mentioned.
The liquid crystal cell selects whether the linearly polarized light transmitted through the polarizer is transmitted while maintaining the polarization direction or transmitted with the polarization direction rotated by 90°, depending on whether the voltage is turned on or off.

As shown in FIG. 1, the liquid crystal cell 106 includes a liquid crystal layer and an electrode pair (a transparent electrode 161 and a transparent electrode 162) for applying a voltage to the liquid crystal layer, as well as an electrode pair (a transparent electrode 161 and a transparent electrode 162) for applying a voltage to the liquid crystal layer.

Alignment films

171 and 172 for aligning liquid crystal molecules, a glass substrate 112, a barrier layer 190, a photospacer 195, and the like may be provided. The barrier layer 190 is a barrier layer against impurities diffusing from the light emitting layer and the λ/4 layer into the liquid crystal cell.

<λ/4 retardation layer>
A λ/4 retardation layer (λ/4 plate) is a plate having an in-plane retardation value of Re(λ)=λ/4 (or an odd multiple thereof) at a predetermined wavelength λnm. This formula should be achieved at any wavelength (for example, 550 nm) in the visible light range.
A known λ/4 retardation layer can be used as the λ/4 retardation layer.

Here, the λ/4 retardation layer is preferably configured using a material whose birefringence is inversely dispersed. As a result, the λ/4 retardation layer can handle light with a wide band of wavelengths.

The λ/4 retardation layer converts linearly polarized light into circularly polarized light, and also converts circularly polarized light into linearly polarized light.

<Light emitting layer>
The light-emitting layer is excited by light emitted from the backlight unit to emit light, and is also excited by external light incident from the outside of the liquid crystal display device to emit light, thereby converting the wavelength of light. is. The light-emitting layer may have a plurality of light-emitting regions that emit light of different wavelengths corresponding to each pixel. For example, as in the example shown in FIG. 1, the light-emitting layer includes a red light-emitting region 131R that emits red light when excited by ultraviolet light, a green light-emitting region 131G that emits green light, and a blue light-emitting region that emits blue light. 131B, respectively. Further, in the example shown in FIG. 1, partition walls (black matrix) 132 are provided to partition each light emitting region.

As the light-emitting layer (light-emitting region), various known light-emitting layers (wavelength conversion layers) in which a phosphor is dispersed in a matrix such as a curable resin can be used. For example, when external light or excitation light from a backlight unit is incident on the light-emitting layer, the light-emitting layer converts at least part of the excitation light into red, green, or blue light due to the effect of the phosphor contained therein. Wavelength-converted and emitted. The excitation wavelength for exciting the light-emitting layer is preferably in the ultraviolet region.

Here, ultraviolet light means light having a central wavelength in a wavelength band of 200 nm or more and 380 nm or less, and blue light means light having a central wavelength in a wavelength band of 400 nm or more and 500 nm or less. Light is light having an emission central wavelength in a wavelength band of more than 500 nm and not more than 600 nm, and red light is light having an emission central wavelength in a wavelength band of more than 600 nm and not more than 680 nm.

The phosphor is at least excited by incident excitation light and emits fluorescence.
The type of phosphor contained in the fluorescent layer is not particularly limited, and various known phosphors may be appropriately selected according to the required wavelength conversion performance.
Examples of such phosphors include organic fluorescent dyes and organic fluorescent pigments, phosphors obtained by doping phosphates, aluminates, metal oxides with rare earth ions, metal sulfides, metal nitrides, and the like. Examples include a phosphor obtained by doping a semiconducting substance with activation ions, and a phosphor utilizing a quantum confinement effect known as a quantum dot. Among them, quantum dots, which have a narrow emission spectrum width, can realize a light source with excellent color reproducibility when used in a display, and have excellent emission quantum efficiency, are preferably used in the present invention.

Regarding quantum dots, for example, paragraphs 0060 to 0066 of JP-A-2012-169271 can be referred to, but they are not limited to those described here. Moreover, a commercial item can be used for a quantum dot without any restrictions. The emission wavelength of quantum dots can usually be adjusted by the composition and size of the particles.

The phosphors are preferably uniformly dispersed in the matrix, but may be unevenly distributed in the matrix. Moreover, only 1 type may be used for fluorescent substance and it may use 2 or more types together.
When two or more phosphors are used together, two or more phosphors having different wavelengths of emitted light may be used.

Also, as the quantum dot, a so-called quantum rod or a tetrapod-type quantum dot, which has a rod-like shape and emits polarized light with directivity, may be used.

In addition, various known matrices used in the light-emitting layer can be used. Suitable matrix materials include epoxies, acrylates, norbornenes, polyethylenes, poly(vinyl butyral): poly(vinyl acetate), polyureas, polyurethanes; aminosilicones (AMS), polyphenylmethylsiloxanes, polyphenylalkylsiloxanes, polydiphenyl Silicones and silicone derivatives, including but not limited to siloxanes, polydialkylsiloxanes, silsesquioxanes, fluorinated silicones, and vinyl- and hydride-substituted silicones; including but not limited to methyl methacrylate, butyl methacrylate, and lauryl methacrylate styrenic polymers such as polystyrene, aminopolystyrene (APS), and poly(acrylonitrile ethylene styrene) (AES); polymers crosslinked with difunctional monomers such as divinylbenzene; cross-linking agents suitable for cross-linking with ligand materials, epoxides that combine with ligand amines (eg, APS or PEI ligand amines) to form epoxies, and the like.

Alternatively, a polymerizable composition (coating composition) containing two or more polymerizable compounds may be cured as the matrix of the light-emitting layer.

The matrix that forms the light-emitting layer, in other words, the polymerizable composition that forms the light-emitting layer, may contain necessary components such as viscosity modifiers and solvents, if necessary. In other words, the polymerizable composition that forms the light-emitting layer is a polymerizable composition for forming the light-emitting layer.

In the light-emitting layer, the amount of the matrix resin may be appropriately determined according to the type of functional material contained in the light-emitting layer.

The thickness of the light-emitting layer may also be appropriately determined according to the type and application of the light-emitting layer. When the light-emitting layer contains quantum dots, the thickness of the light-emitting layer is preferably 5 to 200 μm, more preferably 10 to 150 μm, from the viewpoint of handleability and light emission properties.
The thickness of the light-emitting layer is intended to be the average thickness, and the average thickness is obtained by measuring the thickness of the light-emitting layer at 10 or more arbitrary points and arithmetically averaging them.

If necessary, a polymerization initiator, a silane coupling agent, or the like may be added to the polymerizable composition that forms the light-emitting layer.

<Backlight unit>
The backlight unit emits light having an excitation wavelength that excites the light-emitting layer. As shown in FIG. 1, the backlight unit is preferably a planar light source that emits planar light. The backlight unit may have a light source that emits excitation light and a light guide plate that guides and planarly emits the excitation light emitted from the light source. They may be arranged in a plane.

As a light source, a light-emitting diode, a laser light source, or the like having a central wavelength in the excitation wavelength band can be used. When the excitation wavelength is in the ultraviolet region, an ultraviolet light emitting diode that emits ultraviolet light may be used as the light source.

In addition, the backlight unit may have a diffusion film that diffuses light, a reflector that is arranged on the side opposite to the emission surface side, and the like.

<Visible light reflective layer>
The visible light reflecting layer reflects at least the wavelength of the light emitted by the light-emitting layer, and has a wavelength-selective reflectivity of transmitting the light of the wavelength of the excitation light that excites the light-emitting layer.

As the visible light reflecting layer that selectively reflects light of a specific wavelength, a cholesteric liquid crystal layer obtained by fixing a cholesteric liquid crystal phase, or a plurality of optically anisotropic layers and isotropic layers alternately laminated. A laminate (so-called dielectric multilayer film) is preferably used.

<<dielectric multilayer film>>
The dielectric multilayer film has a structure in which optically anisotropic layers and isotropic layers are alternately laminated.
A film in which layers with a low refractive index (low refractive index layers) and layers with a high refractive index (high refractive index layers) are alternately laminated has a structural structure between many low refractive index layers and high refractive index layers. Interference is known to reflect certain wavelengths of light.

The wavelength reflected by the dielectric multilayer film and the reflectance can be adjusted by the refractive index difference between the low refractive index layer and the high refractive index layer, thickness, lamination layers, and the like. Specifically, the thickness d of the low refractive index layer and the high refractive index layer is set to d = λ / (4 × n) from the wavelength λ of the reflected light and the refractive index n, so that the reflected light can be adjusted. In addition, since the reflectance increases as the number of layers of the low refractive index layer and the number of the high refractive index layers increases, the reflectance can be adjusted by adjusting the number of layers. Also, the width of the reflection band can be adjusted by the difference in refractive index between the low refractive index layer and the high refractive index layer.

Therefore, when a dielectric multilayer film is used as the visible light reflecting layer, the low refractive index layer and the high refractive index layer are combined so that the selective reflection center wavelength of the dielectric multilayer film is in a range including the wavelength emitted by the light emitting layer. The refractive index difference, thickness, lamination layers, etc. may be adjusted. The visible light reflective layer includes, for example, an R reflective layer that reflects red light emitted by the luminescent layer, a G reflective layer that reflects green light emitted by the luminescent layer, and a blue reflective layer that reflects blue light emitted by the luminescent layer. A configuration having a B reflective layer may also be used. In this case, the refractive index difference between the low-refractive-index layer and the high-refractive-index layer of the dielectric multilayer film as each reflective layer, the thickness, the lamination layers, etc. are adjusted, and the selective reflection central wavelength of each reflective layer is adjusted. A desired range may be obtained.

Here, the bandwidth of the reflection peak in the dielectric multilayer film depends on the difference between the refractive index in the slow axis direction of the optically anisotropic layer and the refractive index of the isotropic layer. Increased bandwidth. Therefore, by adjusting the difference between the refractive index in the slow axis direction of the optically anisotropic layer and the refractive index of the isotropic layer to adjust the bandwidth of the reflection peak in the dielectric multilayer film, The reflection bandwidth can be adjusted (widened).

Materials that are particularly preferably used as the dielectric multilayer film include PEN (polyethylene naphthalate) and PET (polyethylene terephthalate) as the optically anisotropic layer, and (isotropically adjusted d) PEN, PET and PMMA (polymethyl methacrylate resin).

The dielectric multilayer film can be formed by conventionally known methods such as stretching and extrusion molding. Further, in the case of a configuration having a plurality of dielectric multilayer films, after forming each dielectric multilayer film, the dielectric multilayer films may be bonded together to form a visible light reflecting layer. Alternatively, the thickness before processing may be adjusted so that a plurality of different dielectric multilayer films are formed, and the plurality of dielectric multilayer films may be integrally formed by stretching, extrusion molding, or the like.

The thickness of the dielectric multilayer film is preferably in the range of 2.0-50 μm, more preferably in the range of 8.0-30 μm.

<<Cholesteric liquid crystal layer>>
A cholesteric liquid crystal layer means a layer in which a cholesteric liquid crystal phase is fixed. The cholesteric liquid crystal layer may be any layer as long as the orientation of the liquid crystal compound in the cholesteric liquid crystal phase is maintained. For example, the cholesteric liquid crystal layer is a layer obtained by aligning a polymerizable liquid crystal compound in a cholesteric liquid crystal phase, polymerizing it by ultraviolet irradiation or heating, and curing it. The cholesteric liquid crystal layer is preferably a layer that has no fluidity, and at the same time, is a layer that has been changed to a state in which an external field or external force does not cause a change in the alignment state.
In the cholesteric liquid crystal layer, it is sufficient that the optical properties of the cholesteric liquid crystal phase are maintained in the layer, and the liquid crystal compound in the layer may no longer exhibit liquid crystallinity. For example, the polymerizable liquid crystal compound may be polymerized by a curing reaction and no longer have liquid crystallinity.

Cholesteric liquid crystal phases are known to exhibit selective reflectivity at specific wavelengths. In a general cholesteric liquid crystal phase, the central wavelength of selective reflection (selective reflection central wavelength) λ depends on the helical pitch P in the cholesteric liquid crystal phase, and follows the relationship between the average refractive index n of the cholesteric liquid crystal phase and λ = n × P. . Therefore, by adjusting this helical pitch, the selective reflection central wavelength can be adjusted. The selective reflection central wavelength of the cholesteric liquid crystal phase becomes longer as the helical pitch becomes longer.
The helical pitch is one pitch of the helical structure of the cholesteric liquid crystal phase (the period of the helical structure), in other words, one turn of the helical structure. In other words, the helical pitch is the length in the helical axis direction at which the director of the liquid crystal compound constituting the cholesteric liquid crystal phase (long axis direction in the case of a rod-like liquid crystal compound) rotates 360°.

The helical pitch of the cholesteric liquid crystal phase depends on the type of chiral agent used together with the liquid crystal compound and the addition concentration of the chiral agent when forming the cholesteric liquid crystal layer. Therefore, a desired helical pitch can be obtained by adjusting these.
That is, when the cholesteric liquid crystal layer is used as the visible light reflecting layer, the type of chiral agent and the additive concentration of the chiral agent are adjusted so that the central wavelength of selective reflection of the cholesteric liquid crystal layer is in the range including the emission wavelength of the light emitting layer. It is sufficient to adjust the helical pitch of the cholesteric liquid crystal phase by adjusting. The visible light reflecting layer includes, for example, a cholesteric liquid crystal layer that reflects red light emitted by the light emitting layer, a cholesteric liquid crystal layer that reflects green light emitted by the light emitting layer, and a blue light that is reflected by the light emitting layer. A configuration including a cholesteric liquid crystal layer may be employed. In this case, the type of chiral agent used in forming each cholesteric liquid crystal layer and the concentration of the chiral agent added are adjusted so that the central wavelength of selective reflection of each cholesteric liquid crystal layer falls within the desired range. The helical pitch of the cholesteric liquid crystal phase may be adjusted.

For pitch adjustment, refer to Fujifilm Research Report No. 50 (2005) p. 60-63 for a detailed description. As for the method of measuring the sense and pitch of the helix, the methods described in "Introduction to Liquid Crystal Chemistry Experiments", edited by the Japanese Liquid Crystal Society, published by Sigma Publishing, 2007, page 46, and "Liquid Crystal Handbook", Liquid Crystal Handbook Editing Committee, Maruzen, page 196 are used. be able to.

In addition, the cholesteric liquid crystal phase exhibits selective reflectivity for either left or right circularly polarized light at a specific wavelength. Whether the reflected light is right-handed circularly polarized light or left-handed circularly polarized light depends on the twist direction (sense) of the spiral of the cholesteric liquid crystal phase. The selective reflection of circularly polarized light by the cholesteric liquid crystal phase reflects right circularly polarized light when the spiral of the cholesteric liquid crystal phase is twisted to the right, and reflects left circularly polarized light when the spiral is twisted to the left. Therefore, when a cholesteric liquid crystal layer is used as the visible light reflecting layer, the visible light reflecting layer consists of a cholesteric liquid crystal layer that reflects right-handed circularly polarized light in a wavelength range including the emission wavelength of the light emitting layer, and the light emitting wavelength of the light emitting layer. and a cholesteric liquid crystal layer that reflects left-handed circularly polarized light in a wavelength range including For example, a cholesteric liquid crystal layer that reflects right-handed circularly polarized red light emitted by the light-emitting layer, a cholesteric liquid crystal layer that reflects left-handed circularly polarized red light emitted by the light-emitting layer, and a cholesteric liquid crystal layer that reflects right-handed circularly polarized green light emitted by the light-emitting layer. A reflecting cholesteric liquid crystal layer, a cholesteric liquid crystal layer reflecting left-handed circularly polarized green light emitted by the light-emitting layer, a cholesteric liquid crystal layer reflecting right-handed circularly polarized blue light emitted by the light-emitting layer, and blue light emitted by the light-emitting layer. A configuration having a cholesteric liquid crystal layer that reflects left-handed circularly polarized light is preferable.
The direction of rotation of the cholesteric liquid crystal phase can be adjusted by the type of liquid crystal compound forming the cholesteric liquid crystal layer and/or the type of chiral agent added.

In addition, in the cholesteric liquid crystal layer, the half width Δλ (nm) of the selective reflection band (circularly polarized light reflection band) indicating selective reflection depends on Δn of the cholesteric liquid crystal phase and the spiral pitch P, and is given by Δλ=Δn×P. Follow relationship. Therefore, the width of the selective reflection band can be controlled by adjusting Δn. Δn can be adjusted by the type and mixing ratio of the liquid crystal compounds forming the cholesteric liquid crystal layer, and the temperature during orientation fixation. Therefore, the wavelength bandwidth can be adjusted by adjusting the type and mixing ratio of the liquid crystal compounds, the temperature at the time of orientation fixation, and the like to adjust the half width Δλ of the selective reflection band.

In addition, in the case of widening the wavelength bandwidth in the reflective layer, it may be configured to have two or more cholesteric liquid crystal layers with different selective reflection wavelengths. By forming the reflective layer into a structure in which two or more cholesteric liquid crystal layers having different selective reflection wavelengths are laminated, the reflection band of the reflective layer can be widened.

(Method for Forming Cholesteric Liquid Crystal Layer)
The method of forming the cholesteric liquid crystal layer is not particularly limited, and may be formed by various known methods. For example, a cholesteric liquid crystal layer is prepared by dissolving a liquid crystal compound, a chiral agent, a polymerization initiator, and a surfactant added as necessary in a solvent. It can be formed by applying it to the formed base layer, drying it to obtain a coating film, orienting the liquid crystal compound in the coating film, and irradiating the coating film with an actinic ray to cure the liquid crystal composition. .

In the case where the visible light reflective layer has a plurality of cholesteric liquid crystal layers, after each cholesteric liquid crystal layer is formed on a support, the layers are peeled off from the support and bonded together to form a plurality of cholesteric liquid crystal layers. A visible light reflecting layer having a structure in which liquid crystal layers are laminated may be formed. Alternatively, after the first cholesteric liquid crystal layer is formed on the support, the next cholesteric liquid crystal layer is sequentially formed on the previously formed cholesteric liquid crystal layer so that a plurality of cholesteric liquid crystal layers are laminated. You may form the visible light reflection layer which has.

(liquid crystal compound)
The liquid crystal compound used for forming the cholesteric liquid crystal layer is not particularly limited, and various known rod-like liquid crystal compounds and discotic liquid crystal compounds are used. Moreover, a polymerizable liquid crystal compound is preferable.

As a liquid crystal compound, Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), U.S. Pat. No. 4,683,327, U.S. Pat. 22586, WO 1995/24455, WO 1997/00600, WO 1998/23580, WO 1998/52905, WO 2016/194327 and WO 2016/052367 Publications, JP-A-1-272551, JP-A-6-16616, JP-A-7-110469 and JP-A-11-80081, and JP-A-2001-328973, etc. Compounds are exemplified.
The liquid crystal composition may contain two or more liquid crystal compounds.

The content of the liquid crystal compound in the liquid crystal composition is not particularly limited, but is preferably 80 to 99.9% by mass, and preferably 84 to 99.9% by mass based on the solid content mass (mass excluding the solvent) of the liquid crystal composition. 5% by mass is more preferable, and 87 to 99% by mass is even more preferable.

(chiral agent)
Various known chiral agents can be used.
A chiral agent has a function of inducing a helical structure of a cholesteric liquid crystal phase. Depending on the chiral agent, the induced helical sense or helical pitch is different, so it may be selected depending on the purpose. The force by which the chiral agent induces the helical structure of the cholesteric liquid crystal phase is called helical twisting power (HTP). When the same concentration of chiral agent is used, the higher the HTP of the chiral agent, the smaller the helical pitch.

Examples of chiral agents include Liquid Crystal Device Handbook (Chapter 3, Section 4-3, Chiral Agents for TN and STN, page 199, Japan Society for the Promotion of Science, 142nd Committee, 1989), and JP-A-2003-287623. Publications, JP-A-2002-302487, JP-A-2002-80478, JP-A-2002-80851, JP-A-2010-181852 and JP-A-2014-034581 and the like are exemplified. be.
A chiral agent generally contains an asymmetric carbon atom, but an axially chiral compound or planar chiral compound that does not contain an asymmetric carbon atom can also be used as the chiral agent. Examples of axially or planarly chiral compounds include binaphthyl, helicene, paracyclophane and derivatives thereof. The chiral agent may have a polymerizable group.

When both the chiral agent and the liquid crystal compound have a polymerizable group, the polymerization reaction of the polymerizable chiral agent and the polymerizable liquid crystal compound produces a repeating unit derived from the polymerizable liquid crystal compound and a repeating unit derived from the chiral agent. can form a polymer having repeating units with In this aspect, the polymerizable group possessed by the polymerizable chiral agent is preferably the same type of group as the polymerizable group possessed by the polymerizable liquid crystal compound.
Also, the chiral agent may be a liquid crystal compound. The chiral agent may also be a chiral agent that undergoes re-isomerization, dimerization, isomerization and dimerization, etc. upon irradiation with light, thereby changing HTP.

The content of the chiral agent in the liquid crystal composition is preferably 0.01 to 200 mol%, more preferably 1 to 30 mol%, relative to the total molar amount of the liquid crystal compound.

(Other additives)
If necessary, the liquid crystal composition further contains a polymerization initiator, a cross-linking agent, an alignment control agent, a surfactant, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, a coloring material, and a metal. Oxide fine particles and the like may be contained within a range that does not degrade the optical performance. Moreover, the liquid crystal composition may contain a solvent.

<Color absorption layer>
The color absorption layer absorbs light in at least a part of the wavelength range other than the wavelength emitted by the light emitting layer and the excitation wavelength of the light emitting layer.

A material that absorbs light in a predetermined wavelength range may be used as the light absorption layer. Alternatively, the resin may contain a light absorbing material.
For example, when the light to be absorbed is visible light, a colored resin material, paper, an inorganic material, or the like can be used as the absorption layer.
The light-absorbing material is not limited, and known light-absorbing materials can be used depending on the wavelength range to be absorbed. For example, when the light to be absorbed is visible light, known light absorbers such as inorganic pigments, organic pigments such as insoluble azo pigments, and dyes such as azo and anthraquinone can be used. The inorganic pigment is a composite oxide pigment, for example, _{cobalt green (TiO2.CoO.NiO.ZrO2 or CoO.Cr2O3.TiO2.Al2O3} ₎ _is exemplified for _green , _and _cobalt for blue _. Blue (CoO.Al ₂ O ₃ ) is exemplified, and red is iron oxide (Fe ₂ O ₃ ). Lead molybdate, lead chromate, and their mixtures are exemplified as materials having blue-green absorption.

Also, the light absorption layer may be configured to have two or more light absorption materials that absorb light in different wavelength ranges. For example, the light-absorbing layer includes a light-absorbing material that exhibits absorption in a wavelength range between the wavelength at which the red light-emitting region emits light and the wavelength at which the green light-emitting region emits light, the wavelength at which the green light-emitting region emits light, and the By having a light-absorbing material that exhibits absorption in a wavelength range between the wavelength at which the light is emitted, the light in at least a part of the wavelength range other than the wavelength at which the light-emitting layer emits light and the excitation wavelength of the light-emitting layer is absorbed. shall be allowed.

The thickness of the light absorption layer is preferably in the range of 1 to 10 µm, more preferably in the range of 1 to 3 µm.

The present invention will be described in more detail below based on examples. Materials, usage amounts, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed to be limited by the examples shown below.

[Example 1]
<Production of the first laminate>
A first laminate 102 portion of the liquid crystal display device 100 as shown in FIG. 1 was produced as follows.
Non-alkali glass having a thickness of 0.5 mm was used as the glass substrate 111 . On the glass substrate 111, a visible light reflecting layer 121 having a property of transmitting light having a transmission wavelength of about 385 nm as shown in FIG.

Next, grid-like partition walls 132 with a height of 10 μm and an opening size of 100×300 μm were formed on the visible light reflecting layer 121 by photolithography using a photosensitive black resist. A red light-emitting region 131R, a green light-emitting region 131G, and a blue light-emitting region 131B are formed by photolithography using a phosphor resist having an excitation wavelength of 385 nm in the openings corresponding to the RGB pixels of the grid-like partition wall 132, and a light-emitting layer is formed. 131 was formed. FIG. 6 shows the optical properties of the phosphor resist used.

Next, a laminated film of the λ/4 retardation layer 141 and the first polarizer 151 was transferred onto the light-emitting layer 131 in a predetermined optical axis direction.

For the first polarizer 151, a polarizing element obtained by dyeing a PVA (polyvinyl alcohol) resin with a dichroic dye as described below was used.

<Production of first polarizer>
0.01% of the dye of compound (1), 0.01% of the dye (red, 2BP; C.I. Direct Red 81) manufactured by Toa Kasei Co., Ltd., and 0 of the dye represented by the following structural formula (2) 0.03%, 0.03% of the dye represented by the following structural formula (3), and 0.1% of Glauber's salt in an aqueous solution at 45° C., and polyvinyl alcohol (PVA) with a thickness of 75 μm as a substrate for 4 minutes. Soaked.
This film was stretched 5 times in a 3% boric acid aqueous solution at 50°C, washed with water while maintaining tension, and dried to obtain a neutral color (gray in the parallel position and black in the orthogonal position). 1 polarizer 151 was obtained.

compound (1)

Structural formula (2)

Structural formula (3)

A barrier layer 190 was formed by coating and baking a transparent resin on the first polarizer 151 . Further, an ITO (indium tin oxide) film was formed as a transparent electrode 161 on the barrier layer 190 by sputtering.

<Production of the second laminate>
A portion of the second laminate 103 of the liquid crystal display device 100 as shown in FIG. 1 was manufactured as follows.
As the glass substrate 112, non-alkali glass having a thickness of 0.5 mm, which is the same as the glass substrate 111, was used. A black matrix 192 was formed on the glass substrate 112 in a shape corresponding to the partition walls 132 of the first laminate 102 by photolithography. Next, an ITO film was formed by sputtering and etched in stripes so as to have a shape corresponding to the RGB pixels of the first laminate 102 to form

transparent electrodes

162R, 162G and 162B corresponding to each pixel. Next, photospacers 195 having a height of 5 μm and a diameter of 10 μm were formed at the position of the black matrix with an appropriate density to form the second laminate 103 .

<Encapsulation of liquid crystal layer>
A polyimide film was applied to the transparent electrode side surface of each of the first laminated body 102 and the second laminated body 103 produced, and baked. The polyimide film formed on the first laminate 102 was subjected to optical rubbing so that the alignment axis coincided with the optical axis of the first polarizer 151 to form an alignment film 171 . The polyimide film formed on the second laminate 103 was subjected to optical rubbing so that the alignment axis was perpendicular to the optical axis of the first polarizer 151 to form an alignment film 172 .

Next, a UV curing epoxy resin was dispensed so as to surround along the edge of the surface of the alignment film 172 side of the second laminate 103 to prepare a sealing pattern. Using an ODF (one drop fill) device, a twisted nematic liquid crystal material is dropped on the alignment film 172 side of the second laminate 103, and placed in a vacuum so that the alignment film 171 side of the first laminate 102 is on the liquid crystal side. They were laminated together and the edge epoxy resin was UV-cured and sealed. A liquid crystal layer 180 was formed by subjecting the liquid crystal material to a low temperature treatment at a predetermined temperature for initial alignment treatment.

Next, the second polarizer 152 was attached to the surface of the glass substrate 112 opposite to the liquid crystal layer 180 with an adhesive so that the optical axis coincided with the light distribution axis of the alignment film 172 .

<Fabrication of backlight unit>
LED (light-emitting diode) chips with a wavelength of 385 nm were mounted on a PCB (polychlorinated biphenyl) substrate in an array and wired, and a diffusion sheet was bonded to the light-emitting surface side to produce a backlight unit 101 .

A liquid crystal display device 100 was produced by arranging the backlight unit 101 on the glass substrate 111 side of the laminate produced above.

[Example 2]
A liquid crystal display device 200 as shown in FIG. 4 was manufactured in the same manner as in Example 1, except that the color absorption layer 242 was arranged between the glass substrate 212 and the second polarizer 252 as follows.
After encapsulating the liquid crystal layer 280, a color absorption layer 242 having light absorption characteristics as shown in FIG. Next, the second polarizer 252 was pasted on the color absorption layer 242 with an adhesive so that the optical axis coincided with the light distribution axis of the alignment film 272 .

[Comparative Example 1]
A liquid crystal display device as shown in FIG. 8 was manufactured in the same manner as in Example 1 except that the λ/4 retardation layer was not provided and the visible light reflecting layer was changed to a reflecting layer 321 formed as follows. bottom.

<Production of the first laminate>
A first laminate 302 portion of the liquid crystal display device 300 as shown in FIG. 8 was manufactured as follows.
Non-alkali glass with a thickness of 0.5 mm was used as the glass substrate 311 . An aluminum film having a thickness of 100 nm was formed on the glass substrate 311 by sputtering, and the reflective layer 321 was formed by etching leaving half of each pixel region.

Next, grid-like partition walls 332 with a height of 10 μm and an opening size of 100×300 μm were formed on the reflective layer 321 by photolithography using a photosensitive black resist. A red light-emitting region 331R, a green light-emitting region 331G, and a blue light-emitting region 331B are formed by photolithography using a phosphor resist having an excitation wavelength of 385 nm in the openings corresponding to the RGB pixels of the grid-like partition wall 132, and a light-emitting layer is formed. 331 was formed. The optical properties of the phosphor resist used are the same as those shown in FIG.

Next, the first polarizer 351 was transferred onto the light-emitting layer 331 in a predetermined optical axis direction. A barrier layer 390 was formed by coating and baking a transparent resin on the first polarizer 351 . Furthermore, a transparent electrode 361 was formed on the barrier layer 390 by sputtering an ITO film.

[Comparative Example 2]
A liquid crystal display device was produced in the same manner as in Example 1, except that the λ/4 retardation layer was not provided.

[evaluation]
The following evaluations were performed on the manufactured liquid crystal display device. As a preparation, a lead electrode was connected to the transparent electrode of the manufactured liquid crystal display device with a silver paste. In addition, in the measurement room, outside light was diffused by a diffuser from a window to adjust the indirect illuminance to about 100000 lx (average illuminance outdoors) before use.

<Color gamut measurement>
First, in the transmission mode, the color coordinates of each of RGB were measured using CM700d (manufactured by Minolta). The backlight unit was turned on and adjusted to a luminance of 10000 cd/m ² . The voltage applied to the liquid crystal layer was 5 V applied to the pixels other than the color to be measured to turn them off, so that each color of RGB was lit in a single color, and the color coordinates were measured.

Next, with the backlight unit turned off, the color coordinates of each of RGB were measured using a CM700d (manufactured by Minolta) in a reflection mode using external light with an indirect illuminance of about 100,000 lx. The voltage applied to the liquid crystal layer was 5 V applied to the pixels other than the color to be measured to turn them off, so that each color of RGB was lit in a single color, and the color coordinates were measured.

<Panel surface reflectance>
With the backlight unit turned off and all pixels turned off, a spectrometer (Minolta CM700d) was used to measure the light reflected from the surface or inside of the liquid crystal display device from the light source built into the spectrometer. .

<Contrast>
Contrast in reflection mode using ambient light with an indirect illumination of about 100000 lx was measured with SR-UL1R (Topcon). With the backlight unit turned on, the contrast was defined as the luminance ratio between the voltage applied to all pixels of 5 V for all black and the voltage applied to all pixels of 0 V for all white.

The results are shown in Table 1.

From Table 1, it can be seen that the example of the present invention has a higher contrast than the comparative example, and the difference in color gamut between the transmissive mode and the reflective mode is small.
Also, from the comparison between Example 1 and Example 2, it can be seen that the presence of the color absorption layer increases the contrast.
From the above results, the effect of the present invention is clear.

100, 200, 300, 400 liquid crystal display device 101, 201, 301, 401 backlight unit 102, 202, 302 first laminate 103, 203, 303 second laminate 105, 205, 305, 405 liquid crystal panel 106, 206 , 306 liquid crystal cell 111, 112, 211, 212, 311, 312, 411, 412 glass substrate 121, 221 visible light reflecting layer 131, 231, 331 light emitting layer 131R, 231R, 331R red light emitting region 131G, 231G, 331G green light emitting Regions 131B, 231B, 331B Blue light-emitting regions 132, 232, 332 Partitions 141, 241 λ/4 retardation layer 242 Color absorption layer 151, 251, 351, 451 First polarizer 152, 252, 352, 452 Second polarizer 161, 162R, 162G, 162B, 261, 262R, 262G, 262B, 361, 362R, 362G, 362B, 461R, 461G, 461B, 462 transparent electrode 171, 172, 271, 272, 371, 372 orientation film 180, 280, 380, 480 liquid crystal layer 190, 290, 390 barrier layer 192, 292, 392, 492 black matrix 195, 295, 395 photospacer 321, 421R, 421G, 421B reflective layer 441R, 441G, 441B λ/4 layer 465R red color filter 465G green color filter 465B blue color filter

Claims

A liquid crystal display device including a backlight unit and a liquid crystal panel,
the liquid crystal panel includes, from the backlight side, a first polarizer, a liquid crystal cell, and a second polarizer;
A light-emitting layer between the backlight unit and the liquid crystal cell that emits light when excited by light emitted from the backlight unit and emits light when excited by external light incident from the outside of the liquid crystal display device. further having
Having a λ / 4 retardation layer between the first polarizer and the light emitting layer,
A liquid crystal display device comprising a visible light reflecting layer between the light emitting layer and the backlight unit.
2. The liquid crystal display device according to claim 1, further comprising a color absorption layer that absorbs light in at least a part of the wavelength range other than the wavelength emitted by the light emitting layer and the excitation wavelength of the light emitting layer, on the viewing side of the light emitting layer. .
The liquid crystal display device according to claim 1 or 2, wherein the backlight unit emits light having a wavelength that excites the light emitting layer.
The liquid crystal display device according to claim 1 or 2, wherein the light-emitting layer contains a phosphor.
3. The liquid crystal according to claim 1, wherein the light-emitting layer has a red light-emitting region that emits light upon excitation of red light, a green light-emitting region that emits light upon excitation of green light, and a blue light-emitting region that emits light upon excitation of blue light. display device.