WO2012147681A1

WO2012147681A1 - Liquid crystal display device

Info

Publication number: WO2012147681A1
Application number: PCT/JP2012/060836
Authority: WO
Inventors: 康浅岡; 大輔槻尾; 和広出口; 藤原　小百合; 佐藤　英次
Original assignee: シャープ株式会社
Priority date: 2011-04-26
Filing date: 2012-04-23
Publication date: 2012-11-01

Abstract

A liquid crystal display device (100A) of the present invention is provided with: a liquid crystal display panel (50A); and a light beam direction converting element (20) that is arranged on the viewer side of the liquid crystal display panel (50A). The liquid crystal display panel (50A) is provided with: a liquid crystal layer (1) that can be switched between a transmitting state that transmits light and a scattering state that scatters light; a first substrate (2) and a second substrate (3) that hold the liquid crystal layer (1) therebetween; and a pair of electrodes (4, 8) that apply a voltage to the liquid crystal layer (1). The liquid crystal layer (1) has a continuous wall (10) and a liquid crystal region (11) within a pixel. The liquid crystal region (11) contains a nematic liquid crystal material and a dichroic fluorescent dye (17). The light beam direction converting element (20) turns the traveling direction of fluorescence emitted from the dichroic fluorescent dye (17) to a predetermined direction.

Description

Liquid crystal display

The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having a dichroic fluorescent dye.

Liquid crystal display devices are widely used as liquid crystal televisions, monitors, mobile phones and the like as flat panel displays having features such as thinness and light weight. However, the most widely used liquid crystal display device at present is a system using two or one polarizing plate, and there is a problem that the light use efficiency is low.

So far, as a display method that does not use a polarizing plate, a guest-host method or a polymer dispersed liquid crystal (PDLC) method has been proposed (for example, Patent Document 1).

Patent Document 1 discloses a liquid crystal display device in which a hologram element is disposed between a PDLC liquid crystal display panel and a reflector. A liquid crystal layer (PDLC layer) of a PDLC liquid crystal display panel has a plurality of liquid crystal regions (also referred to as “liquid crystal droplets”) dispersed in a polymer. Each liquid crystal region is formed in a space (hereinafter referred to as “small room”) defined by a wall made of a polymer. In such a PDLC layer, when no voltage is applied (when no voltage is applied), a difference in refractive index is generated between the liquid crystal material in the liquid crystal region and the polymer for vertically incident light. The light is scattered and white display is obtained. When a voltage is applied to the PDLC layer (when a voltage is applied), the alignment of the liquid crystal changes and the refractive indexes of the liquid crystal and the polymer become substantially equal, so that light passes through the PDLC layer without being scattered. At this time, a black element is displayed by arranging a hologram element on the back side of the PDLC layer and diffracting light transmitted through the PDLC layer by the hologram element in a direction of a critical angle or more.

JP 11-337923 A

On the other hand, the present applicant has developed a PDLC-type liquid crystal display device having a dichroic fluorescent dye (for example, PCT / JP2011 / 073830 (hereinafter referred to as Patent Application 1) and International Publication No. 2011/1. 136072 (hereinafter referred to as Patent Application 2) For the purpose of reference, the entire disclosure of

Patent Applications

1 and 2 is incorporated herein by reference.

The liquid crystal display device disclosed in Patent Application 1 has a dichroic fluorescent dye in a plurality of liquid crystal regions dispersed in a polymer. In addition, the liquid crystal region is formed in contact with the alignment film to control the alignment of the liquid crystal molecules in the liquid crystal region, thereby controlling the alignment of the dichroic fluorescent dye. As a result, the luminous efficiency of the dichroic fluorescent dye is increased and the contrast ratio is improved.

However, the PDLC liquid crystal display device having such a dichroic fluorescent dye has room for improving the luminance in the front view.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal display device having a dichroic fluorescent dye with enhanced brightness in a front view.

A liquid crystal display device according to the present invention includes a liquid crystal display panel, a light beam direction conversion element disposed on an observer side of the liquid crystal display panel, and an air layer provided between the liquid crystal display panel and the light beam direction conversion element. The liquid crystal display panel includes a liquid crystal layer that can be switched between a transmission state that transmits light and a scattering state that scatters light, a first substrate that holds the liquid crystal layer therebetween, and a first substrate Two substrates and a pair of electrodes for applying a voltage to the liquid crystal layer, the liquid crystal layer having a continuous wall and a liquid crystal region in the pixel, the liquid crystal region comprising a nematic liquid crystal material and 2 The light direction changing element directs the traveling direction of the fluorescence emitted from the dichroic fluorescent dye in a predetermined direction.

In one embodiment, a pair of electrodes for applying a voltage to the liquid crystal layer is disposed with the liquid crystal layer interposed therebetween, and the liquid crystal region includes a first liquid crystal region separated by the wall.

In one embodiment, the liquid crystal display device is in contact with the liquid crystal layer between at least one of the liquid crystal layer and the first substrate and between the liquid crystal layer and the second substrate. A horizontal alignment film formed is further provided.

In one embodiment, the liquid crystal display device includes first and second alignment layers formed between the liquid crystal layer and the first substrate and between the liquid crystal layer and the second substrate and subjected to alignment treatment. The liquid crystal region includes a second liquid crystal region separated by the wall and the first alignment film, and a third liquid crystal region separated by the wall and the second alignment film, The dichroic fluorescent dye in the second liquid crystal region is aligned along a first orientation defined by the first alignment film, and the dichroic fluorescent dye in the third liquid crystal region is the second Aligned along the second orientation defined by the alignment film.

In one embodiment, the first orientation and the second orientation are orthogonal.

In certain embodiments, the surface free energy of the first and second alignment films is 44 mJ / m ² or more 50 mJ / m ² or less.

In one embodiment, a pair of electrodes for applying a voltage to the liquid crystal layer is formed on one of the first substrate and the second substrate, between the liquid crystal layer and the first substrate, and A first liquid crystal region including first and second vertical alignment films formed between the liquid crystal layer and the second substrate, wherein the liquid crystal region is separated by the wall and the first vertical alignment film; And a second liquid crystal region separated by the wall and the second vertical alignment film, wherein the dichroic fluorescent dyes in the first and second liquid crystal regions are the first and second vertical alignments, respectively. It is oriented along the orientation defined by the film.

A liquid crystal display device according to another embodiment of the present invention includes a liquid crystal display panel, a light beam direction conversion element disposed on the viewer side of the liquid crystal display panel, and the liquid crystal display panel and the light beam direction conversion element. The liquid crystal display panel includes a fluorescent light-emitting layer having a plurality of dichroic fluorescent dye molecules, the intensity of light emission being different depending on a light emission direction, a light transmitting state and light. A liquid crystal layer that can be switched between a scattering state and a scattering state. The liquid crystal layer includes a continuous wall and a liquid crystal region including a nematic liquid crystal material in a pixel, and the plurality of 2 Each of the chromatic fluorescent dye molecules is oriented in the fluorescent light-emitting layer so that the direction of the transition dipole moment is the same in each molecule, and the light beam direction changing element includes the plurality of dichroic elements. Each of the fluorescent molecules The traveling direction of the emitted fluorescence from oriented in a predetermined direction.

In one embodiment, each of the plurality of dichroic fluorescent dye molecules is oriented in the fluorescent light emitting layer such that the direction of the transition dipole moment coincides with the thickness direction of the fluorescent light emitting layer.

In one embodiment, an ultraviolet absorbing layer that absorbs ultraviolet rays is provided between the fluorescent light emitting layer and the liquid crystal layer.

In one embodiment, the fluorescent light-emitting layer includes a light-emitting layer formed in a sheet shape (in a self-supporting manner) and an adhesive layer that adheres the light-emitting layer to an adherend, the light-emitting layer and the adhesive At least one of the layers includes an ultraviolet absorber.

In one embodiment, the liquid crystal display panel has a pair of electrodes for applying a voltage to the liquid crystal layer, and the pair of electrodes is a pair of comb-teeth electrodes.

In one embodiment, the above-described liquid crystal display device includes a light guide plate that guides light from a light source to the fluorescent light emitting layer between the fluorescent light emitting layer and the light beam direction conversion element.

In one embodiment, the liquid crystal display device includes a photovoltaic power generation unit that receives light emitted from the dichroic fluorescent dye molecules in the fluorescent light emitting layer and generates power outside the surface of the fluorescent light emitting layer. I have.

In one embodiment, the photovoltaic unit is provided such that a light receiving surface thereof faces a surface direction end of the fluorescent light emitting layer.

In one embodiment, the above-described liquid crystal display device further includes an antireflection layer disposed on the light beam direction conversion element side of the liquid crystal display panel.

In one embodiment, the liquid crystal display device further includes an antireflection layer disposed on the liquid crystal display panel side of the light beam direction conversion element.

In one embodiment, the liquid crystal display device further includes an antireflection layer disposed on the light beam direction conversion element side of the liquid crystal display panel and on the liquid crystal display panel side of the light beam direction conversion element.

In one embodiment, the difference between the extraordinary refractive index ne and the ordinary refractive index no of the nematic liquid crystal material included in the liquid crystal region is 0.1 or more and 0.3 or less.

In one embodiment, the liquid crystal region does not contain a chiral agent.

In one embodiment, the dielectric anisotropy of the nematic liquid crystal material is positive.

In one embodiment, the diffraction angle of the light beam redirecting element is 40 ° or more and 70 ° or less.

According to the present invention, there is provided a liquid crystal display device having a dichroic fluorescent dye with increased brightness in front view.

(A) is typical sectional drawing of liquid crystal display device 100A in embodiment by this invention, (b) is a figure explaining the light beam direction conversion element 20, (c) is liquid crystal display device 100A. It is a graph which shows the relationship between the fluorescence brightness | luminance and viewing angle. (A) And (b) is a schematic diagram for demonstrating a dichroic fluorescent dye, (c) is a wavelength ((lambda)), an absorption coefficient, and a fluorescence emission coefficient about a dichroic fluorescent dye. It is a graph explaining the relationship. It is typical sectional drawing of 50 A of liquid crystal display panels. It is a graph which shows the relationship between fluorescence luminance and a viewing angle. It is typical sectional drawing of 50 A of liquid crystal display panels. It is a graph which shows the measurement result of reflection characteristics. 3 is a diagram illustrating a hologram element 21. FIG. (A) is typical sectional drawing of liquid crystal display device 100B in other embodiment by this invention, (b) And (c) is a figure explaining the orientation of the dichroic fluorescent dye 17. FIG. (A) And (b) is typical sectional drawing of 100 C of liquid crystal display devices in further another embodiment by this invention. (A) And (b) is a figure explaining the reflection preventing layer 80. FIG. It is the graph which showed the relationship between fluorescence luminance and a viewing angle. It is typical sectional drawing of liquid crystal display device 100D in further another embodiment by this invention. It is a figure explaining liquid crystal display device 100D. It is a figure explaining liquid crystal display device 100D. It is a figure explaining the modification of liquid crystal display device 100D. It is a figure explaining the further modification of liquid crystal display device 100D. It is typical sectional drawing of the liquid crystal display device 100E in other embodiment by this invention. It is typical sectional drawing of the liquid crystal display device 100F in further another embodiment by this invention. It is a figure explaining the modification of liquid crystal display device 100F. It is typical sectional drawing of the liquid crystal display device 100G in other embodiment by this invention. (A) is a typical top view of the liquid crystal display device 100H in further another embodiment by this invention, (b) is sectional drawing along the II-II 'line | wire of (a).

Hereinafter, a liquid crystal display device according to an embodiment of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the illustrated embodiment.

A liquid crystal display device 100A according to an embodiment of the present invention will be described with reference to FIG.

FIG. 1A is a cross-sectional view schematically showing the liquid crystal display device 100A. FIG. 1B is a diagram for explaining the light beam direction conversion element 20 and shows portions corresponding to two pixels. FIG. 1C is a graph showing the relationship between the fluorescence brightness and the viewing angle of the liquid crystal display device 100A.

As shown in FIG. 1A, the liquid crystal display device 100A includes a liquid crystal display panel 50A and a light beam direction conversion element (for example, a hologram element) 20. The liquid crystal display panel 50A includes a liquid crystal layer 1 that can be switched between a transmission state that transmits light and a scattering state that scatters light, and a first substrate (for example, a glass substrate) that holds the liquid crystal layer 1 therebetween. 2 and a second substrate (for example, a glass substrate) 3 and a pair of

electrodes

4 and 8 for applying a voltage to the liquid crystal layer 1. The liquid crystal layer 1 has a continuous wall 10 and a liquid crystal region 11 in a pixel. The liquid crystal region 11 includes a nematic liquid crystal material (not shown) and a dichroic fluorescent dye (not shown in FIG. 1A). The light beam direction conversion element 20 that directs the traveling direction of the fluorescence emitted from the dichroic fluorescent dye in a predetermined direction (for example, the normal direction of the display surface of the liquid crystal display device 100A) is placed on the viewer side of the liquid crystal display panel 50A. Has been placed. In the liquid crystal display device according to the embodiment of the present invention, black display is not obtained using a hologram element, unlike the liquid crystal display device disclosed in Patent Document 1.

As shown in FIG. 1B, the fluorescence F1 emitted from the dichroic fluorescent dye is refracted by, for example, the normal direction of the display surface of the liquid crystal display device 100A by the light direction conversion element 20, and viewed from the front (for example, The luminance of fluorescence in the direction of the normal direction of the display surface of the liquid crystal display device 100A increases. As shown in FIG. 1C, the luminance of the fluorescence in the front view direction is higher than the luminance of the fluorescence in the direction shifted from the front view direction.

Further, in the liquid crystal display device 100A shown in FIG. 1A,

alignment films

12 and 13 are formed on the first substrate 2 and the second substrate 3 so as to be in contact with the liquid crystal layer 1, respectively. The

alignment films

12 and 13 are, for example, horizontal alignment films. Note that only one of the

alignment films

12 and 13 may be formed, or neither of them may be formed. On the liquid crystal layer 1 side of the first substrate 2, for example, a thin film transistor (TFT) 5 and a pixel electrode 4 are formed for each pixel. The pixel electrode 4 is a reflective electrode formed from, for example, Al (aluminum). A transparent electrode 8 made of, for example, ITO (Indium 透明 Tin Oxide) is formed on the liquid crystal layer 1 side of the second substrate 3.

The liquid crystal layer 1 of the liquid crystal display device 100A has a small room 14 divided by a wall 10. There are a plurality of small rooms 14. The continuous wall 10 is made of, for example, a polymer. A liquid crystal region 11 is formed in the small chamber 14. Each liquid crystal region 11 has a nematic liquid crystal material and a dichroic fluorescent dye. The nematic liquid crystal material and the dichroic fluorescent dye in the liquid crystal region 11 include those not in contact with the

alignment films

12 and 13.

The material for forming the liquid crystal layer 1 is not particularly limited, but the nematic liquid crystal material for forming the liquid crystal layer 1 preferably has a positive dielectric anisotropy. When the dielectric anisotropy of a nematic liquid crystal material is negative and the alignment film that regulates the alignment of liquid crystal molecules in the nematic liquid crystal material is a vertical alignment film, the liquid crystal molecules are parallel to the substrate when a voltage is applied. I must fall down. However, in this case, the direction in which the liquid crystal molecules are tilted cannot be regulated, and the liquid crystal molecules in the liquid crystal region are likely to be disturbed from uniform alignment, and disclination occurs in the liquid crystal region, thereby preventing the movement of the liquid crystal molecules. There is a fear. In order to use the display principle described later, the liquid crystal layer preferably does not contain a chiral agent. Further, the birefringence Δn (difference between the extraordinary refractive index ne and the ordinary refractive index no) of the nematic liquid crystal material of the liquid crystal layer 1 is preferably 0.1 or more and 0.3 or less. When the birefringence Δn is 0.1 or more, the contrast ratio of display can be increased. On the other hand, if the birefringence index Δn is 0.3 or less, there are many choices of materials, and it may be possible to reduce voltage and speed.

The liquid crystal layer 1 is prepared by, for example, mixing a nematic liquid crystal material (that is, a low-molecular liquid crystal composition) and a photocurable resin (monomer and / or oligomer) and disposing the photocurable resin between transparent substrates. Obtained by polymerization. Although the kind of photocurable resin is not specifically limited, Preferably an ultraviolet curable resin is used. When an ultraviolet curable resin is used, there is no need to heat the mixture when polymerization is performed, so that adverse effects due to heat on other members can be prevented. Monomers and oligomers may be monofunctional or polyfunctional.

In the present embodiment, the liquid crystal layer 1 is formed by photocuring a mixture (liquid crystal mixture) of an ultraviolet curable resin and a liquid crystal composition by irradiation with an actinic ray such as ultraviolet rays. As the liquid crystal mixture, for example, a liquid crystal mixture showing a nematic liquid crystal phase at room temperature obtained by mixing an ultraviolet curable material and liquid crystal at a weight ratio of 20:80 and adding a small amount of a photoinitiator is used. Can do.

The liquid crystal mixture is held between the pair of

substrates

2 and 3 by, for example, a vacuum injection method or a drop injection (ODF) method and then irradiated with ultraviolet rays. As a result, the ultraviolet curable resin is polymerized to form a polymer, which is phase-separated from the liquid crystal, thereby forming a liquid crystal layer 1 having a polymer wall 10 and a plurality of liquid crystal regions 11 separated from each other by the wall 10. The That is, one liquid crystal region 11 is surrounded by the wall 10.

Next, the dichroic fluorescent dye will be described with reference to FIG. FIG. 2A and FIG. 2B are diagrams illustrating a dichroic fluorescent dye. FIG. 2C is a graph illustrating a dichroic fluorescent dye. The dichroic fluorescent dye includes a p-type and an n-type dichroic fluorescent dye. In the present embodiment, a p-type dichroic fluorescent dye is used.

2A and 2C, in the p-type dichroic fluorescent dye, the molecular axis and the absorption transition moment (absorption axis) 31a face the same direction. Thereby, the absorption coefficient (A //) of light oscillating in a direction parallel to the molecular axis is larger than the absorption coefficient (A⊥) of light oscillating in a direction perpendicular to the molecular axis. The opposite is true for n-type dichroic fluorescent dyes. Therefore, when the p-type dichroic fluorescent dye is aligned so that the absorption axis 31a is parallel to the substrate, the absorption efficiency of light incident from the outside entering the liquid crystal layer 1 is increased. In addition, if there are two regions in which the absorption axis 31a is orthogonal in the thickness direction of the liquid crystal layer 1, it becomes possible to efficiently absorb all polarization components of light from the outside.

Furthermore, as shown in FIGS. 2 (b) and 2 (c), the p-type dichroic fluorescent dye has the molecular axis and the transition moment (emission axis) 31b of the fluorescence emission oriented in substantially the same direction. Thereby, the fluorescence emission coefficient (F //) of the light emitted in the direction perpendicular to the molecular axis is larger than the fluorescence emission coefficient (F⊥) of the light emitted in the direction parallel to the molecular axis. The opposite is true for n-type dichroic fluorescent dyes. Therefore, for example, when the p-type dichroic fluorescent dye is oriented so that the emission axis 31b is parallel to the substrate, the fluorescence emission intensity is large when viewed from the normal direction of the display surface of the liquid crystal display panel 50A. Become.

Next, the liquid crystal display panel 50A will be described with reference to FIGS. FIG. 3 is a diagram illustrating the liquid crystal panel 50A when no voltage is applied, and FIG. 5 is a diagram illustrating the liquid crystal display panel 50A when a voltage is applied. FIG. 4 is a graph showing the luminance with respect to the viewing angle of the liquid crystal display panel 50A. FIG. 6 is a graph showing SCE (regular reflection light removal) reflectance measurement results in the respective states when the liquid crystal display panel 50A is in the transparent state and the scattering state.

As shown in FIG. 3, when no voltage is applied, the nematic liquid crystal material (not shown) in the liquid crystal region 11 is randomly oriented. The dichroic fluorescent dye 17 is randomly oriented depending on the orientation direction of the nematic liquid crystal material. That is, the liquid crystal layer 1 is in a scattering state when no voltage is applied.

The light incident on the liquid crystal layer 1 from the outside is scattered, and the light in the excitation wavelength region (350 nm to 500 nm) of the dichroic fluorescent dye 17 is absorbed by the dichroic fluorescent dye 17. As a result, the dichroic fluorescent dye 17 emits fluorescence. A part of the fluorescently emitted light F1 is emitted from the surface of the liquid crystal display panel 50A to the outside without being scattered by the liquid crystal layer 1. The majority (approximately 74%) of the fluorescently emitted light F1 is totally reflected at the interface between the liquid crystal display panel 50A and the air layer, and is guided inside the liquid crystal display panel 50A. The fluorescence F1 guided through the liquid crystal display panel 50A is reflected and scattered, and the traveling direction becomes smaller than the total reflection angle, and is emitted to the liquid crystal display panel 50A. The liquid crystal layer 1 in the scattering state emits 60% or more of the fluorescent light F1 to the outside of the liquid crystal display panel 50A. As a result, bright color display is possible by the fluorescent light F1 and the scattered external light.

However, most of the light that is repeatedly reflected and scattered and is emitted to the outside of the liquid crystal display panel 50A has a small scattering angle in the liquid crystal layer 1 in a scattering state and is substantially forward scattered. The light is emitted in a direction shifted from the normal direction of the surface. However, when the emission angle exceeds 60 °, the interface reflectance increases, and the fluorescence luminance decreases. As a result, the fluorescence luminance distribution is as shown in FIG. 4, and the fluorescence luminance is low near the front (angle 0 ° in FIG. 4), and is near 50 ° from the normal direction of the display surface of the liquid crystal display panel 50A. The fluorescence brightness is maximized.

As shown in FIG. 5, the nematic liquid crystal material (not shown) in the liquid crystal region 11 of the liquid crystal layer 1 is aligned perpendicular to the first substrate 2 when a voltage is applied. Depending on the alignment direction of the nematic liquid crystal material, the dichroic fluorescent dye 17 is also aligned perpendicular to the first substrate 2. As a result, the liquid crystal layer 1 becomes transparent.

When the liquid crystal layer 1 is in a transparent state, light incident from the outside is transmitted without being scattered, is regularly reflected by a reflecting plate (for example, the reflective electrode 4), and is emitted to the outside of the liquid crystal display panel 50A. The light in the excitation wavelength region of the dichroic fluorescent dye 17 is hardly absorbed by the dichroic fluorescent dye 17 because the dichroic fluorescent dye 17 is oriented perpendicular to the first substrate 2. As a result, the fluorescent light F1 is small and most of the light F1 is emitted in a direction parallel to the first substrate 2. Accordingly, most of the fluorescent light F1 is guided through the liquid crystal display panel 50A. Further, the display is black except for the regular reflection direction with respect to the light source (external light).

Next, when the liquid crystal display panel 50A having the absorption wavelength in the vicinity of the wavelength of 420 nm and having the dichroic fluorescent dye 17 that emits fluorescence in the vicinity of the wavelength of 540 nm is in the transparent state T1 or the scattering state D1, the respective states are changed to Konica Minolta. CM2002 (diffuse light source / 8 ° light reception) was used to measure SCE (regular reflection light removal) reflectivity. As a result, the result shown in FIG. 6 was obtained, and it was found that display with a contrast ratio of 10: 1 was obtained.

Next, the light beam direction conversion element 20 will be described with reference to FIG. FIG. 7 is a diagram illustrating the light beam direction conversion element 20.

In this embodiment, the light beam direction conversion element 20 is a hologram element 21, for example. The hologram element 21 is preferably a volume phase hologram element. In the liquid crystal display device 100A, the light beam direction conversion element 20 is disposed on the viewer side of the liquid crystal display panel 50A. The light beam direction conversion element 20, for example, applies fluorescence emitted toward the direction of 40 ° to 60 ° from the normal direction of the display surface of the liquid crystal display panel 50 A (liquid crystal display device 100 A) to the display surface of the liquid crystal display panel 50 A. Refract in the line direction. For example, the light direction conversion element 20 increases the luminance of the liquid crystal display device 100A in a front view. Moreover, it is preferable to arrange the light beam direction conversion element 20 and the liquid crystal display panel 50A so as to sandwich the air layer therebetween. When the light beam direction conversion element 20 and the liquid crystal display panel 50A are thus arranged, the luminance in the front view direction is further increased, and the luminance in the direction deviated from the normal direction of the display surface of the liquid crystal display device 100A is further decreased.

In manufacturing the hologram element 21, it is preferable to use the maximum emission wavelength (for example, wavelength 540 nm) of the dichroic fluorescent dye 17 for the object light O1 and the reference light R1 (see FIG. 7). Further, it is preferable to irradiate the object light O1 from the normal direction of the main surface of the hologram element 21. The reference light R1 is preferably applied to the hologram element 21 with an incident angle θ from the side opposite to the side on which the object light O1 is incident on the hologram element 21. Here, the incident angle θ is preferably, for example, 40 ° or more and 70 ° or less, and more preferably 50 °. Further, the reference light R1 is not limited to being irradiated from one direction, and is more preferably irradiated from all directions. Therefore, the diffraction angle of the hologram element 21 is preferably 40 ° or more and 70 ° or less, and more preferably 50 °. The reason will be explained. When the observer observes from the normal direction (front direction) of the liquid crystal display device 100A, the observer sees light emitted in the 0 ° to 40 ° direction from the front direction. For this reason, even if the light emitted in the 0 ° to 40 ° direction from the front direction is refracted in the front direction, the effect that the observer feels bright is small. On the other hand, the light emitted at an angle of 70 ° or more from the front direction is reflected at the liquid crystal display panel 50A / air interface and the air / hologram element 21 interface, so that there is little light incident on the hologram element 21 and the front direction. Less light is refracted into For this reason, even if the light emitted in the direction of 70 ° or more from the front direction is refracted to the front direction side, the effect that the observer feels bright is small.

Next, a liquid crystal display device 100B according to another embodiment of the present invention will be described with reference to FIG. Note that the same reference numerals are assigned to components common to the liquid crystal display device 100A. FIG. 8A is a schematic cross-sectional view of the liquid crystal display device 100B.

As shown in FIG. 8A, the liquid crystal display device 100B includes a liquid crystal display panel 50B and a light beam direction conversion element 20. The liquid crystal display panel 50B includes a first substrate (for example, a glass substrate) 2, a second substrate (for example, a glass substrate) 3 disposed so as to face the first substrate 2, and the first substrate 2 and the second substrate. The liquid crystal layer 1 is provided between the liquid crystal layer 1 and the liquid crystal layer 1. Further,

alignment films

12 and 13 are subjected to, for example, a rubbing process, and define the alignment orientation of nematic liquid crystal molecules of the liquid crystal layer 1 in contact therewith. For example, the orientation orientation by the orientation film 12 and the orientation orientation by the orientation film 13 are orthogonal. In addition to the rubbing treatment, the orientation orientation can be defined by a photo-alignment treatment or the like. The light direction conversion element 20 is arranged on the viewer side of the liquid crystal display panel 50B.

The liquid crystal layer 1 has a small room 14 a divided by the wall 10 and the alignment film 12 and a small room 14 b divided by the wall 10 and the alignment film 13. The continuous wall 10 is made of, for example, a polymer. A liquid crystal region 11a is formed in the small chamber 14a, and a liquid crystal region 11b is formed in the small chamber 14b. Each of the

liquid crystal regions

11 a and 11 b has a nematic liquid crystal material (not shown) and a dichroic fluorescent dye 17. The nematic liquid crystal material and the dichroic fluorescent dye 17 in the liquid crystal region 11 a are in contact with the alignment film 12. The nematic liquid crystal material and the dichroic fluorescent dye 17 in the liquid crystal region 11 b are in contact with the alignment film 13. The nematic liquid crystal material and the dichroic fluorescent dye 17 in the liquid crystal region 11 a are aligned along the rubbing direction of the alignment film 12, and the nematic liquid crystal material and the dichroic fluorescent dye 17 in the liquid crystal region 11 b are aligned with the alignment film 13. Oriented along the rubbing direction. The dichroic fluorescent dye 17 is aligned so as to be parallel to the alignment direction of the nematic liquid crystal material.

In order for the

small chambers

14a and 14b to be formed by being divided by the

alignment films

12 and 13 and the wall 10, respectively, it is preferable to optimize the surface free energy of the

alignment films

12 and 13. This is a knowledge obtained as a result of various studies by the present inventors. A preferred range of the surface free energy will vary depending on the material forming the liquid crystal layer 1, for example, it is 44 mJ / m ² or more 50 mJ / m ² or less.

As described above, when the

small chambers

14a and 14b are formed so that the nematic liquid crystal material and the dichroic fluorescent dye 17 are in contact with the

alignment films

12 and 13, respectively, the alignment of the nematic liquid crystal material and the dichroic fluorescent dye 17 is controlled. can do. For example, when the orientation of the dichroic fluorescent dye 17 is controlled so that the orientation orientation of the dichroic fluorescent dye 17 in the liquid crystal region 11a and the orientation orientation of the dichroic fluorescent dye 17 in the liquid crystal region 11b are orthogonal to each other, Since light (for example, light having a wavelength of 430 nm) can be efficiently absorbed by the fluorescent dye 17, low-voltage driving is possible and color developability can be improved.

The liquid crystal display device 100B includes a TFT 5 formed on the liquid crystal layer 1 side of the first substrate 2 and formed for each pixel. Further, the liquid crystal display device 100 B includes a pixel electrode 4 formed for each pixel and an alignment film 12 in contact with the liquid crystal layer 1, which is formed on the liquid crystal layer 1 side of the first substrate 2. The alignment film 12 is a horizontal alignment film and has been rubbed. Furthermore, the liquid crystal display device 100 B includes a transparent electrode 8 formed on the liquid crystal layer 1 side of the second substrate 3 and an alignment film 13 formed so as to be in contact with the liquid crystal layer 1. Similar to the alignment film 12, the alignment film 13 is a horizontal alignment film, and is subjected to a rubbing process. As described above, the

alignment films

12 and 13 are formed so that the rubbing direction of the alignment film 12 and the rubbing direction of the alignment film 13 are orthogonal to each other.

FIG. 8B and FIG. 8C are diagrams for explaining the orientation direction of the dichroic fluorescent dye 17 when no voltage is applied. FIG. 8B is a view taken along line Ia-Ia ′ of FIG. FIG. 8C is a view taken along the line Ib-Ib ′ of FIG.

As shown in FIG. 8B, when no voltage is applied, the major axis direction (director) 30 of the dichroic fluorescent dye 17 existing in the liquid crystal region 11a in the vicinity of the alignment film 12 indicates the liquid crystal display device 100B on the display surface. When viewed from the normal direction, the liquid crystal layer 1 is parallel to the column direction. As shown in FIG. 8C, when no voltage is applied, the major axis direction (director) 30 of the dichroic fluorescent dye 17 existing in the liquid crystal region 11b in the vicinity of the alignment film 13 causes the liquid crystal display device 100B to be displayed on the display surface. When viewed from the normal direction, the liquid crystal layer 1 is parallel to the row direction. That is, the director 30 in the liquid crystal region 11a and the director 30 in the liquid crystal region 11b are orthogonal to each other.

When a voltage is applied to the liquid crystal layer 1 of the liquid crystal display device 100B, as described in the liquid crystal display device 100A, the liquid crystal layer 1 becomes transparent (see FIG. 5).

Like the liquid crystal display device 100B, the light absorption efficiency of the dichroic fluorescent dye can be increased by orienting the dichroic fluorescent dye 17 in parallel with the plane of the first substrate 2 when no voltage is applied. .

Next, a liquid crystal display device 100C according to still another embodiment of the present invention will be described with reference to FIG. FIG. 9A is a schematic cross-sectional view of the liquid crystal display device 100C when no voltage is applied, and FIG. 9B is a schematic cross-sectional view of the liquid crystal display device 100C when a voltage is applied. .

As shown in FIG. 9, the liquid crystal display device 100 C includes a liquid crystal display panel 50 C and a light beam direction conversion element 20. The liquid crystal display panel 50C includes a liquid crystal layer 1 that can be switched between a transmission state that transmits light and a scattering state that scatters light, and a first substrate (for example, a glass substrate) that holds the liquid crystal layer 1 therebetween. 2 and a second substrate (for example, a glass substrate) 3 and a pair of

electrodes

54 and 58 for applying a voltage to the liquid crystal layer 1. The pair of

electrodes

54 and 58 is a so-called pair of comb electrodes. A vertical alignment film (not shown) is formed on the first substrate 2 and the second substrate 3 so as to be in contact with the liquid crystal layer 1. The liquid crystal layer 1 has a continuous wall 10 and a liquid crystal region 11 in a pixel. The liquid crystal region 11 includes a nematic liquid crystal material (not shown) and a dichroic fluorescent dye 17. The liquid crystal region 11 includes a liquid crystal region 11 a separated from each other by a vertical alignment film (not shown) formed on the first substrate 2 and the wall 10, and a vertical alignment film (not shown) formed on the second substrate 3. And a liquid crystal region 11 b separated from each other by the wall 10. That is, the

liquid crystal regions

11a and 11b are respectively surrounded by the wall 10 and the vertical alignment film. The light beam direction conversion element 20 that directs the traveling direction of the fluorescence emitted from the dichroic fluorescent dye 17 in a predetermined direction (for example, the normal direction of the display surface of the liquid crystal display device 100C) is the viewer side of the liquid crystal display panel 50C. Is arranged.

As shown in FIG. 9A, when no voltage is applied, the nematic liquid crystal material (not shown) in the liquid crystal region 11 is aligned perpendicular to the first substrate 2. The dichroic fluorescent dye 17 is oriented perpendicular to the first substrate 2 depending on the orientation of the nematic liquid crystal material. Therefore, when no voltage is applied, the liquid crystal layer 1 is in a transparent state.

As shown in FIG. 9B, when a voltage is applied to the liquid crystal layer 1, the nematic liquid crystal material (not shown) in the liquid crystal region 11 is aligned parallel to the lines of electric force. Depending on the nematic liquid crystal material, the dichroic fluorescent dye 17 is aligned parallel to the nematic liquid crystal material. As a result, the birefringence Δn of the nematic liquid crystal material changes periodically, so that the liquid crystal layer 1 is in a scattering state. Further, since the dichroic fluorescent dye 17 is also oriented parallel to the plane of the first substrate 2, the amount of fluorescent light emission is increased and the luminance is increased.

The electrode 54 and the electrode 58 are preferably formed of a transparent electrode such as ITO. When a pair of

electrodes

54 and 58 are formed on one substrate (for example, the first substrate 2) as in the liquid crystal display device 100C, light is emitted from the dichroic fluorescent dye 17 and guided inside the liquid crystal display panel 50C. The light to be emitted can be efficiently guided to the liquid crystal layer 1. That is, the influence of light absorption and reflection at the electrode interface can be reduced. Therefore, in the liquid crystal display device 100C, the influence of light absorption and reflection at the electrode interface can be reduced, and a display with high luminance can be obtained.

As shown in FIG. 10, for example, an antireflection layer 80 is preferably disposed between the light beam redirecting element 20 and the liquid crystal display panel 50 (50A to 50C). The antireflection layer 80 is, for example, an antireflection film having a moth-eye structure disclosed in International Publication No. 2006/059686. As shown in FIG. 10A, the antireflection layer 80 is disposed on the light beam direction conversion element 20 side of the liquid crystal display panel 50. The transmittance of light emitted in an angle direction of 50 ° or more from the normal direction of the display surfaces of the liquid crystal display devices 100A to 100C is drastically reduced due to interface reflection (see FIG. 4). However, when the antireflection layer 80 is arranged as described above (see FIG. 10A), the interface reflection of light is suppressed, and the fluorescent light is efficiently emitted from the liquid crystal display devices 100A to 100C, resulting in high luminance. Become. FIG. 11 shows the measurement results of the luminance distribution of the liquid crystal display panel 160 in which the antireflection layer 80 is disposed and the liquid crystal display panel 150 in which the antireflection layer 80 is not disposed. The vertical axis of the graph of FIG. 11 is the fluorescence luminance, and the horizontal axis is the viewing angle when the normal direction of the display surface of each liquid crystal display panel is 0 °. As can be seen from FIG. 11, the liquid crystal display panel 160 has higher fluorescence luminance at all viewing angles than the liquid crystal display panel 150.

Further, as shown in FIG. 10B, an antireflection layer 80 may be disposed on the liquid crystal display panel 50 side of the light beam direction conversion element 20. When the antireflection layer 80 is arranged in this way, the amount of fluorescent light incident on the light beam direction conversion element 20 can be increased, and the luminance of the liquid crystal display devices 100A to 100C can be increased.

So far, the liquid crystal display devices 100A to 100C in which the liquid crystal region 11 of the liquid crystal layer 1 includes the dichroic fluorescent dye 17 and the nematic liquid crystal material have been described. However, the liquid crystal display device according to the present invention is not limited to this. For example, a liquid crystal display panel in which a dichroic fluorescent dye layer having the dichroic fluorescent dye 17 and a liquid crystal layer having a nematic liquid crystal material are separated is used. You can also. Hereinafter, a liquid crystal display device having such a configuration will be described with reference to FIGS. The description of the light beam direction conversion element 20 is omitted.

A liquid crystal display device 100D according to still another embodiment of the present invention will be described with reference to FIGS. FIG. 12 is a schematic cross-sectional view of the liquid crystal display device 100D. FIG. 13 is a diagram illustrating the liquid crystal display device 100D when a voltage is applied, and FIG. 14 is a diagram illustrating the liquid crystal display device 100D when no voltage is applied. FIG. 15 is a diagram illustrating a modification example of the liquid crystal display device 100D. FIG. 16 is a diagram for explaining a further modification of the liquid crystal display device 100D.

As shown in FIG. 12, the liquid crystal display device 100D includes a liquid crystal display panel 50D and a light beam direction conversion element 20 disposed on the viewer side of the liquid crystal display panel 50D. An air layer 35 is provided between the liquid crystal display panel 50 D and the light beam direction conversion element 20. The liquid crystal display panel 50D includes a fluorescent light emitting layer 31 having a plurality of dichroic fluorescent dye molecules 17a having different light emission strengths depending on the light emitting direction, and a transmission state that transmits light and a scattering state that scatters light. And a liquid crystal layer 33 whose state can be switched. The liquid crystal layer 33 includes a continuous wall 10 made of a polymer and a liquid crystal region 11 having a nematic liquid crystal material in a pixel. The liquid crystal region 11 does not have a plurality of dichroic fluorescent dye molecules 17a. The details of the wall 10 and the nematic liquid crystal material are as described above. Each of the plurality of dichroic fluorescent dye molecules 17a is oriented in the fluorescent light emitting layer 31 so that the direction of the transition dipole moment is the same in each molecule.

In the liquid crystal display panel 50D, the liquid crystal layer 33 and the fluorescent light emitting layer 31 are separated. Accordingly, since it is not necessary to dissolve the fluorescent dye in the liquid crystal layer 33, it is not necessary to increase the thickness of the liquid crystal layer 33 so that a large amount of the fluorescent dye can be added to the liquid crystal layer 33. Further, in order to obtain sufficient fluorescent light emission, the fluorescent light emitting layer 31 may be thickened, so that the light emission amount can be changed without changing the voltage applied to the liquid crystal layer 33.

Furthermore, since the intensity of light emission of the dichroic fluorescent dye molecule 17a in the fluorescent light emitting layer 31 varies depending on the direction of light emission, the refraction state of the strong light emitted from the dichroic fluorescent dye molecule 17a in the display device. It is possible to change the intensity of the fluorescence emission by changing. That is, by controlling the nematic liquid crystal material in the liquid crystal layer 33, brighter light emitted from the dichroic fluorescent dye molecules 17a is scattered by the nematic liquid crystal material and taken out or totally reflected in the liquid crystal display device 100D. Thus, it can be confined in the liquid crystal display device 100D. Therefore, the state of the fluorescence emission of the liquid crystal display device 100D can be changed by controlling the nematic liquid crystal material in the liquid crystal layer 33.

Specifically, the liquid crystal display panel 50D includes, for example, a first substrate 2 on which the pixel electrode 4 and the TFT 5 are formed, a second substrate 3 facing the first substrate 2, and the first substrate 2 and the second substrate 3. And a liquid crystal layer 33 disposed between the two.

On the second substrate 3, a transparent electrode (sometimes referred to as “counter electrode”) 8 and a fluorescent light emitting layer 31 having a plurality of dichroic fluorescent dye molecules 17a are formed. The fluorescent light emitting layer 31 is formed on the liquid crystal layer 33 side of the second substrate 3, and the counter electrode 8 is formed on the liquid crystal layer 33 side of the fluorescent light emitting layer 31.

The liquid crystal layer 33 is a PDLC layer. The liquid crystal layer 33 includes a nematic liquid crystal material and does not include the dichroic fluorescent dye 17. When no voltage is applied, the liquid crystal layer 33 is in a scattering state, and when a voltage is applied to the liquid crystal layer 33, the liquid crystal layer 33 is in a transparent state. Such a PDLC layer is well known and will not be described in detail.

The fluorescent light emitting layer 31 has a dichroic fluorescent dye molecule 17a and a liquid crystalline polymer 23b that holds the dichroic fluorescent dye molecule 17a. The dichroic fluorescent dye molecule 17a is made of a material having an absorption band in an ultraviolet wavelength region (for example, 10 nm to 400 nm) and a visible light wavelength region (for example, 380 nm to 750 nm) and having a dichroic ratio of 5 or more. Have. The dichroic fluorescent dye molecule 17a is, for example, a benzothiadiazole-based or coumarin-based, cyanine-based, pyridine-based, rhodamine-based, styryl-based, or anthraquinone-based fluorescent dye molecule.

As described above, the dichroic fluorescent dye molecule 17a has the property of absorbing fluorescent light such as ultraviolet rays and visible light. The dichroic fluorescent dye molecule 17a oscillates in a direction parallel to the molecular long axis, compared to the absorption coefficient of light that oscillates in the direction intersecting the molecular long axis (light that travels parallel to the molecular long axis). It has an absorption characteristic that the absorption coefficient of light (light traveling in a direction crossing the molecular long axis) is larger (see FIG. 2).

Further, the dichroic fluorescent dye molecule 17a has a light emission characteristic that the fluorescence emission coefficient in the direction parallel to the molecular long axis is larger than the fluorescence emission coefficient in the direction intersecting with the molecular long axis. In the dichroic fluorescent dye molecule 17a, the molecular long axis coincides with the direction of the transition moment of light emission. Accordingly, the dichroic fluorescent dye molecule 17a emits stronger light in the direction crossing the molecular axis. In the following description, the dichroic fluorescent dye molecule 17a is described as a vertically long ellipse, but its longitudinal direction corresponds to the molecular long axis.

As shown in FIG. 12, the liquid crystalline polymer 23b can orient the dichroic fluorescent dye molecules 17a so that the molecular major axis coincides with the stacking direction of each layer (the thickness direction of the fluorescent light emitting layer 31). It has a resin material. Specifically, the liquid crystalline polymer 23b has a compound having a photoreactive group at a molecular terminal or a diacrylate compound having a liquid crystalline skeleton. An ultraviolet absorbing material that absorbs ultraviolet rays may be mixed in the liquid crystalline polymer 23b. Thereby, the ultraviolet-ray which permeate | transmits the fluorescence light emitting layer 31 can be reduced more reliably, and the liquid crystal layer 33 can be protected from an ultraviolet-ray.

As described above, the dichroic fluorescent dye molecules 17a are held in the fluorescent light-emitting layer 31 by the liquid crystal polymer 23b, thereby crossing the molecular long axis of the dichroic fluorescent dye molecules 17a, that is, the liquid crystal display panel 50D. In the in-plane direction, stronger light is emitted from the dichroic fluorescent dye molecule 17a. On the other hand, only weak light is emitted from the dichroic fluorescent dye molecule 17a in the direction parallel to the molecular long axis of the dichroic fluorescent dye molecule 17a, that is, in the thickness direction of the fluorescent light emitting layer 31. Therefore, as indicated by a thin solid line in FIGS. 13 and 14, almost no light is emitted directly from the dichroic fluorescent dye molecule 17a to the outside of the liquid crystal display panel 50D.

As described above, since each layer of the liquid crystal display panel 50D is made of a transparent material, light emitted from the dichroic fluorescent dye molecules 17a in the in-plane direction of the display panel 1 is separated from the liquid crystal display panel 50D and the air. Reflects at the interface. That is, as shown in FIG. 13, when a voltage is applied to the liquid crystal layer 33 and the liquid crystal layer 33 is in a transparent state, the light emitted from the dichroic fluorescent dye molecules 17a is at the interface with air. Since the reflection is totally reflected, the reflection is repeated in the liquid crystal display panel 50D (see the thick arrow in FIG. 13). The light emitted from the dichroic fluorescent dye molecule 17a to the interface with air at an incident angle smaller than the total reflection angle is emitted to the outside as it is.

On the other hand, as shown in FIG. 14, when no voltage is applied to the liquid crystal layer 33 and the liquid crystal layer 33 is in a scattering state, light emitted from the dichroic fluorescent dye molecules 17 a is transmitted through the liquid crystal layer 33. The light is scattered and emitted to the outside of the liquid crystal display panel 50D (see the thick arrow in FIG. 14). Further, a part of the light scattered by the liquid crystal layer 33 is reflected in the liquid crystal display panel 50D and returns to the dichroic fluorescent dye molecule 17a. Therefore, the light absorption amount of the dichroic fluorescent dye molecule 17a is as shown in FIG. More than the case. Thereby, the dichroic fluorescent dye molecule 17a shines brighter than in the case of FIG.

Also, as described above, the dichroic fluorescent dye molecule 17a absorbs ultraviolet rays. Therefore, the amount of ultraviolet rays reaching the liquid crystal layer 33 can be reduced by providing the fluorescent light emitting layer 31 on the viewer side (the side opposite to the liquid crystal layer 33 side) of the liquid crystal display panel 50D of the liquid crystal layer 33.

In FIGS. 13 and 14, the liquid crystal region 11 in the liquid crystal layer 33 is not shown in order to clearly and simply show the difference between the states of the liquid crystal layers 33.

Next, a method for manufacturing the liquid crystal display panel 50D will be described.

First, the fluorescent light emitting layer 31 is formed on the second substrate 3. The fluorescent light emitting layer 31 is formed by, for example, a spin coat method. That is, the dichroic fluorescent dye molecule 17a is added to the liquid crystalline polymer 23b and mixed until the dichroic fluorescent dye molecule 17a is dissolved to prepare a mixed solution. Next, an alignment film (not shown in FIGS. 12 to 14) is formed on the substrate 3 in order to improve the wettability between the mixed solution and the substrate 3. Thereafter, the mixture is coated with a predetermined film thickness on the alignment film by a known method. After heating in this state to evaporate the solvent, ultraviolet rays are irradiated to cure the liquid crystalline polymer 23b. Thereby, the fluorescent light emitting layer 31 is formed on the substrate 3.

Next, the counter electrode 8 is formed on the fluorescent light emitting layer 31 by, for example, sputtering. For example, a photo spacer is formed on the counter electrode 8 by a known method. The photo spacer is formed from a photoresist. Moreover, the 1st board | substrate 2 which has TFT5 is manufactured by a well-known method.

Next, an alignment film (not shown) is formed on the second substrate 3 and / or the first substrate 2. A seal pattern is formed on the second substrate 3 with a photocurable resin. Thereafter, a mixture obtained by mixing a nematic liquid crystal material, a polymerizable monomer, or the like is dropped on the second substrate 3, and the first substrate 2 and the second substrate 3 are superposed in a vacuum.

Next, ultraviolet light with a wavelength of 340 nm or less cut is irradiated from the second substrate 3 side in a state where the above-mentioned mixture spreads in the seal pattern at atmospheric pressure. This cures the sealing resin and forms the PDLC. Thereafter, the seal is completely cured by firing in a state where the second substrate 3 and the first substrate 2 are combined. Thereby, the liquid crystal display panel 50D shown in FIG. 12 is obtained.

Further, as shown in FIG. 15, ultraviolet absorbing films 45 may be arranged on both surfaces of the liquid crystal display panel 50D. Specifically, the ultraviolet absorbing film 45 is attached by the adhesive 46 between the light beam redirecting element 20 and the second substrate 3 and on the opposite side of the first substrate 2 from the liquid crystal layer 33 side. These ultraviolet absorbing films 45 are configured to cut light having a wavelength of 420 nm or less.

Thereby, it is possible to prevent the liquid crystal layer 33 from being irradiated with ultraviolet rays, and the liquid crystal layer 33 can be protected.

So far, the liquid crystal display panel 50D has been a transmissive liquid crystal display panel. However, the liquid crystal display panel 50D may be modified to a reflective liquid crystal display panel 50D '. As shown in FIG. 16, the liquid crystal display panel 50 D ′ is a reflective liquid crystal display panel in which a reflective layer 47 is formed on the first substrate 2.

Specifically, the liquid crystal display panel 50 D ′ includes a reflective layer 47 formed on the first substrate 2 and a pixel electrode 4 formed on the reflective layer 47. In this case, the pixel electrode 4 can be made of, for example, Al (aluminum). In this modified example, the above-described ultraviolet absorbing film 45 is provided on the second substrate 3 side that transmits light. Not only this structure but the structure which does not provide the ultraviolet absorption film 45 may be sufficient.

Next, a liquid crystal display device 100E according to still another embodiment of the present invention will be described with reference to FIG. FIG. 17 is a schematic cross-sectional view of the liquid crystal display device 100E. The liquid crystal display device 100E is different from the liquid crystal display device 100D in the structure of electrodes for applying a voltage to the liquid crystal layer 33.

As shown in FIG. 17, the liquid crystal display device 100E has a liquid crystal display panel 50E and a light beam direction conversion element 20. The light direction conversion element 20 is arranged on the viewer side of the liquid crystal display panel 50E. An air layer 35 is provided between the liquid crystal display panel 50 E and the light beam direction conversion element 20.

A pair of

comb electrodes

4a and 8a are formed on the first substrate 2 of the liquid crystal display panel 50E. The counter electrode 8 is not formed on the second substrate 3. When a voltage is applied to the liquid crystal layer 33 by the pair of

comb electrodes

4a and 8a, the liquid crystal molecules in the liquid crystal layer 33 are controlled according to the electric field generated between the pair of

comb electrodes

4a and 8a.

Here, the transparent counter electrode 8 included in the liquid crystal display device 100D described above has a high absorption rate for visible light. Therefore, when the transparent counter electrode 8 is provided between the fluorescent light emitting layer 31 and the liquid crystal layer 33 as in the liquid crystal display device 100D, the light emitted from the dichroic fluorescent dye molecules 17a of the fluorescent light emitting layer 31 is counter electrode. 8 is reflected or absorbed by the liquid crystal layer 33 and is difficult to reach the liquid crystal layer 33.

On the other hand, when the pair of

comb electrodes

4a and 8a are formed on the first substrate 2 and the counter electrode 8 is not formed on the second substrate 3 as in the liquid crystal display device 100E, the light generated by the counter electrode 8 can be obtained. Therefore, the light emitted from the dichroic fluorescent dye molecules 17a of the fluorescent light emitting layer 31 can be efficiently guided to the liquid crystal layer 33. The liquid crystal display panel 50E can be modified to a reflective liquid crystal display panel. Similarly to the liquid crystal display device 100D, an ultraviolet absorbing film may be attached to both sides of the liquid crystal display panel 50E.

Next, a liquid crystal display device 100F according to still another embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 18, the liquid crystal display device 100F includes a liquid crystal display panel 50F and a light beam direction conversion element 20. The light beam direction conversion element 20 is disposed on the viewer side of the liquid crystal display panel 50F. An air layer 35 is provided between the liquid crystal display panel 50 F and the light beam direction conversion element 20.

The liquid crystal display panel 50 F includes a first substrate 2, a second substrate 3, and a liquid crystal layer 33 disposed between the first substrate 2 and the second substrate 3. A TFT 5 and a pixel electrode 4 are formed on the first substrate 2. A counter electrode 8 is formed on the liquid crystal layer 33 side of the second substrate 3. On the opposite side of the second substrate 3 from the counter electrode 8 side, an ultraviolet absorbing film 45 is attached with an adhesive 46. Further, a fluorescent dye film 61 is pasted on the ultraviolet absorbing film 45 with an adhesive 46. The fluorescent dye film 61 is obtained by forming the fluorescent light emitting layer 31 of the liquid crystal display device 100D into a film shape. That is, the fluorescent dye film 61 is provided with a light emitting layer 61a having dichroic fluorescent dye molecules 17a oriented so that the molecular major axis coincides with the thickness direction of the film 61b. Here, an adhesive layer is formed by the adhesive 46, and the ultraviolet absorbing film 45 corresponds to the adherend. Further, an ultraviolet absorbing layer is formed by the ultraviolet absorbing film 45.

With the configuration like the liquid crystal display device 100F, the fluorescent dye film 61 can efficiently absorb ultraviolet rays, so that the luminous efficiency of the dichroic fluorescent dye molecules 17a is improved. In addition, since the ultraviolet ray that has not been absorbed by the fluorescent dye film 61 can be absorbed by the ultraviolet ray absorbing film 45, the liquid crystal layer 33 is not easily irradiated with the ultraviolet ray. Moreover, the electrode which applies a voltage to the liquid crystal layer 33 of the liquid crystal display panel 50F can be modified to the above-described pair of

comb electrodes

4a and 8a. In this case, the counter electrode 8 may not be formed.

Further, as described above, the fluorescent light emitting layer can be easily formed on the second substrate 3 by using the fluorescent light emitting layer as the fluorescent dye film 61. Further, by using the fluorescent dye film 61 as described above, it is possible to form a fluorescent light emitting layer after the liquid crystal layer 33 is formed. As a result, when the liquid crystal layer 33 is formed, as described in the liquid crystal display device 100D, the ultraviolet rays having a wavelength of 340 nm or less are cut from the second substrate 3 side. By doing so, a member that absorbs ultraviolet rays does not exist in the second substrate 3. Therefore, when the liquid crystal layer 33 is formed, the liquid crystal layer 33 can be efficiently irradiated with ultraviolet rays.

Further, the fluorescent dye film 61 included in the liquid crystal display device 100F can be modified to a fluorescent dye film 71 described below. FIG. 19 is a diagram illustrating a modified example of the liquid crystal display device 100F.

As shown in FIG. 19, the fluorescent dye film 71 is opposite to the film 71b that hardly absorbs ultraviolet rays, the fluorescent light emitting layer 71a having a plurality of dichroic fluorescent dye molecules 17a, and the film 71b side of the fluorescent light emitting layer 71a. And an adhesive layer 71c provided on the side. The pressure-sensitive adhesive forming the adhesive layer 71c is mixed with an ultraviolet absorber that can absorb light (mainly ultraviolet rays) having a wavelength of 420 nm or less. As the ultraviolet absorber, an ultraviolet absorber such as benzotriazole or benzophenone is used. Therefore, an ultraviolet absorption layer is formed by this adhesive. In addition, the 2nd board | substrate 3 respond | corresponds to a to-be-adhered part.

This eliminates the need for providing the ultraviolet absorbing film 45 as in the liquid crystal display device 100F, thereby simplifying the manufacturing process accordingly. In addition, you may put a ultraviolet absorber in the fluorescent light emitting layer 51b instead of an adhesive. By so doing, the fluorescent light emitting layer 51b can absorb almost all ultraviolet rays.

Furthermore, in the configuration of the modification shown in FIG. 19, the fluorescent light emitting layer 71a and the film 71b may be interchanged. In this case, the adhesive layer 71c is provided on the opposite side of the film 71b from the fluorescent light emitting layer 71a. In this configuration, an ultraviolet absorber may be put in one of the film 71b and the adhesive layer 71c.

Next, a liquid crystal display device 100G according to still another embodiment of the present invention will be described with reference to FIG. FIG. 20 is a schematic cross-sectional view of the liquid crystal display device 100G.

The liquid crystal display device 100G is different from the liquid crystal display device 100F in that a light guide plate 82 is provided on the fluorescent light emitting layer 31.

As shown in FIG. 20, the liquid crystal display device 100G includes a liquid crystal display panel 50G and a light beam direction conversion element 20. The light beam direction conversion element 20 is disposed on the viewer side of the liquid crystal display panel 50G. An air layer 35 is provided between the liquid crystal display panel 50 G and the light beam direction conversion element 20.

The liquid crystal display panel 50G includes a first substrate 2 on which the TFT 5 and the pixel electrode 4 are formed, a second substrate 3 on which the counter electrode 8 is formed, a liquid crystal layer 33 disposed therebetween, a light guide plate 82, Have The light guide plate 82 is disposed between the second substrate 3 and the air layer 35.

Furthermore, the liquid crystal display panel 50G has a fluorescent light emitting layer 31 having dichroic fluorescent dye molecules 17a between the second substrate 3 and the light guide plate 82. The fluorescent light emitting layer 31 is bonded to the second substrate 3 with an adhesive 46.

Note that the adhesive 46 between the fluorescent light emitting layer 31 and the second substrate 3 contains an ultraviolet absorber. As a result, light having a wavelength of 420 nm or less (mainly ultraviolet rays) can be absorbed by the ultraviolet absorbent in the pressure-sensitive adhesive 46, and the liquid crystal layer 33 can be prevented from being irradiated with ultraviolet rays. Therefore, an ultraviolet absorbing layer is formed by the adhesive 46.

The light guide plate 82 is a transparent member that does not absorb ultraviolet rays, such as acrylic or polycarbonate, and is configured to guide light from a light source 83 such as an LED (Light Emitting Diode) to the fluorescent light emitting layer 31. That is, the light from the light source 83 is guided to the fluorescent light emitting layer 31 while being reflected in the light guide plate 82. As a result, as shown in FIG. 20, light is incident on the dichroic fluorescent dye molecules 17a of the fluorescent light emitting layer 31 from the direction intersecting the molecular long axis. Therefore, the dichroic fluorescent dye molecule 17a can emit fluorescence more strongly than when light is incident from a direction parallel to the molecular long axis of the dichroic fluorescent dye molecule 17a.

The light source 83 is a light source including the photoexcitation wavelength of the dichroic fluorescent dye molecule 17a. The light source 83 is preferably an LED that emits ultraviolet light, for example. By using such a light source 83, the dichroic fluorescent dye molecule 17a can be made to emit fluorescent light more brightly. A reflection plate 81 is provided at the end of the light guide plate 82 opposite to the light source 83. The light that has traveled to the end of the light guide plate 82 can be reflected and returned into the light guide plate 82 by the reflection plate 81. In addition, the light guide plate 82, the fluorescent light emitting layer 31, and the second substrate 3 are bonded to each other so that light propagation is not hindered.

Next, a liquid crystal display device 100H according to another embodiment of the present invention will be described with reference to FIG. FIG. 21A is a plan view for explaining the liquid crystal display device 100H, and FIG. 21B is a cross-sectional view of the liquid crystal display device 100H along the line II-II ′ of FIG.

The liquid crystal display device 100H is a liquid crystal display device that combines the liquid crystal display panel 50G, the solar cell, and the light beam direction conversion element 20 described above.

As shown in FIG. 21B, the liquid crystal display device 100H includes the liquid crystal display panel 50G and the light beam direction conversion element 20 described above. The light beam direction conversion element 20 is disposed on the viewer side of the liquid crystal display panel 50G. An air layer 35 is provided between the liquid crystal display panel 50 G and the light beam direction conversion element 20. As shown in FIG. 21A, the liquid crystal display device 100H is disposed in an opening 120a of a housing 120 of a portable device or the like, and a solar cell 131 (photovoltaic power generation unit) disposed on the side of the liquid crystal display device 100H. ) Is arranged. The light guide plate 82 of the liquid crystal display device 100H is disposed in the housing 120 so as to be exposed at the opening 120a of the housing 120. In addition, the liquid crystal display device 100H is disposed in the housing 120 so that the first substrate 2 and the second substrate 3 are positioned corresponding to the opening 120a of the housing 120 in a front view.

The light guide plate 82 of the liquid crystal display device 100H is formed in a substantially rectangular shape when viewed from the front. Two light sources 96 are provided at one end in the longitudinal direction, and a reflector 97 is provided at the other end. It has been. Solar cells 131 are arranged on both sides of the light guide plate 82 of the liquid crystal display device 100H in the short direction.

As shown in FIG. 21 (b), the solar cell 131 is arranged such that a power generation surface 131a (light receiving surface) that generates power by receiving light is opposed to a surface direction end of the liquid crystal display device 100H. Thereby, the light emitted from the dichroic fluorescent dye molecules 17 a of the fluorescent light emitting layer 31 in the direction intersecting the molecular long axis can be received by the power generation surface 131 a of the solar cell 131. Since this dichroic fluorescent dye molecule 17a emits fluorescence strongly in the direction intersecting the molecular long axis (the direction of the white arrow in the figure), the dichroic fluorescent dye molecule 17a is twisted by the power generation surface 131a of the solar cell 131. It can receive strong light. Therefore, the solar cell 131 can generate power efficiently.

Moreover, the solar cell 131 is disposed away from the light guide plate 82. When the solar cell 131 is brought into close contact with the light guide plate 82, light that is originally transmitted to the light guide plate 82 is absorbed by the solar cell 131. On the other hand, as described above, by separating the solar cell 131 from the light guide plate 82, it is possible to prevent the solar cell 131 from inhibiting the propagation of light in the light guide plate 82. Thereby, the light emitted by the dichroic fluorescent dye molecules 17a in the fluorescent light emitting layer 31 of the liquid crystal display device 100H can be received by the solar cell 131 and can be generated by the solar cell 131.

Moreover, since the solar cell 131 is disposed so that the power generation surface 131a faces the end in the surface direction of the liquid crystal display device 100H, the light of the dichroic fluorescent dye molecule 17a can be efficiently received by the power generation surface. it can. In addition, since the dichroic fluorescent dye molecule 17a is arranged so that the molecular long axis coincides with the stacking direction of the liquid crystal display device 100H, the light emitted more strongly in the direction intersecting the molecular long axis is emitted. Light can be received by the solar cell 131.

Furthermore, by arranging the solar cell 131 as described above, since sunlight is not directly incident on the power generation surface 131a of the solar cell 131, the temperature rise of the solar cell 131 can be reduced. Therefore, it is possible to prevent a decrease in power generation efficiency due to the temperature increase of the solar cell 131.

Also in the liquid crystal display devices 100D to 100H, the above-described antireflection layer 80 can be disposed between the liquid crystal display panels 50D to 50G and the light beam direction conversion element 20.

As described above, according to the embodiment of the present invention, a liquid crystal display device having a dichroic fluorescent dye with enhanced brightness in a front view is provided. Further, the liquid crystal display devices according to the embodiments of the present invention described above can be used in appropriate combination.

The present invention is applied to a liquid crystal display device and various electric devices using the liquid crystal display device.

1

Liquid crystal layer

2, 3

Substrate

4, 8 Electrode 5 TFT
DESCRIPTION OF SYMBOLS 10 Wall 11

Liquid crystal area

12, 13 Orientation film 14 Small room 20 Light beam direction change element 50A Liquid crystal display panel 100A Liquid crystal display device F1 Fluorescence

Claims

A liquid crystal display panel;
A light beam direction conversion element disposed on the viewer side of the liquid crystal display panel;
An air layer provided between the liquid crystal display panel and the light beam direction conversion element;
The liquid crystal display panel is
A liquid crystal layer that can be switched between a transmission state that transmits light and a scattering state that scatters light; and
A first substrate and a second substrate holding the liquid crystal layer therebetween;
A pair of electrodes for applying a voltage to the liquid crystal layer,
The liquid crystal layer has a continuous wall and a liquid crystal region in a pixel,
The liquid crystal region has a nematic liquid crystal material and a dichroic fluorescent dye,
The liquid crystal display device, wherein the light beam direction conversion element directs a traveling direction of fluorescence emitted from the dichroic fluorescent dye in a predetermined direction.
A pair of electrodes for applying a voltage to the liquid crystal layer is disposed with the liquid crystal layer interposed therebetween,
The liquid crystal display device according to claim 1, wherein the liquid crystal region includes a first liquid crystal region separated by the wall.
A horizontal alignment film formed to be in contact with the liquid crystal layer is further provided between at least one of the liquid crystal layer and the first substrate and between the liquid crystal layer and the second substrate. Item 3. A liquid crystal display device according to Item 2.
Comprising first and second alignment films formed between the liquid crystal layer and the first substrate and between the liquid crystal layer and the second substrate and subjected to alignment treatment;
The liquid crystal region is
A second liquid crystal region separated by the wall and the first alignment layer;
A third liquid crystal region separated by the wall and the second alignment layer;
The dichroic fluorescent dye in the second liquid crystal region is aligned along a first orientation defined by the first alignment film;
4. The liquid crystal display device according to claim 1, wherein the dichroic fluorescent dye in the third liquid crystal region is aligned along a second direction defined by the second alignment film. 5.
The liquid crystal display device according to claim 4, wherein the first orientation and the second orientation are orthogonal to each other.
Surface free energy of the first and second alignment films is 44 mJ / m 2 or more 50 mJ / m 2 or less, the liquid crystal display device according to claim 4 or 5.
A pair of electrodes for applying a voltage to the liquid crystal layer is formed on either the first substrate or the second substrate,
Comprising first and second vertical alignment films formed between the liquid crystal layer and the first substrate and between the liquid crystal layer and the second substrate;
The liquid crystal region is
A first liquid crystal region separated by the wall and the first vertical alignment layer;
A second liquid crystal region separated by the wall and the second vertical alignment layer;
7. The dichroic fluorescent dye in the first and second liquid crystal regions is aligned along an orientation defined by the first and second vertical alignment films, respectively. Liquid crystal display device.
A liquid crystal display panel;
A light beam direction conversion element disposed on the viewer side of the liquid crystal display panel;
An air layer provided between the liquid crystal display panel and the light beam direction conversion element;
The liquid crystal display panel is
A liquid crystal layer that can be switched between a transmission state that transmits light and a scattering state that scatters light; and
A fluorescent light-emitting layer having a plurality of dichroic fluorescent dye molecules having different light emission intensity depending on the light emission direction
The liquid crystal layer has a continuous wall and a liquid crystal region having a nematic liquid crystal material in a pixel,
Each of the plurality of dichroic fluorescent dye molecules is oriented in the fluorescent light-emitting layer so that the direction of the transition dipole moment is the same in each molecule,
The light beam direction conversion element is a liquid crystal display device that directs the traveling direction of fluorescence emitted from each of the plurality of dichroic fluorescent molecules in a predetermined direction.
9. Each of the plurality of dichroic fluorescent dye molecules is oriented in the fluorescent light emitting layer so that the direction of the transition dipole moment coincides with the thickness direction of the fluorescent light emitting layer. Liquid crystal display device.
10. The display device according to claim 8, wherein an ultraviolet absorbing layer that absorbs ultraviolet rays is provided between the fluorescent light emitting layer and the liquid crystal layer.
The fluorescent light-emitting layer has a light-emitting layer formed in a sheet shape, and an adhesive layer that adheres the light-emitting layer to an adherend,
The liquid crystal display device according to claim 8, wherein at least one of the light emitting layer and the adhesive layer contains an ultraviolet absorber.
The liquid crystal display panel has a pair of electrodes for applying a voltage to the liquid crystal layer,
The liquid crystal display device according to claim 8, wherein the pair of electrodes are a pair of comb electrodes.
The liquid crystal display device according to any one of claims 8 to 12, wherein a light guide plate that guides light from a light source to the fluorescent light emitting layer is disposed between the fluorescent light emitting layer and the light beam direction changing element.
14. The photovoltaic device according to claim 8, further comprising a photovoltaic unit that generates light by receiving light emitted from the dichroic fluorescent dye molecules in the fluorescent light-emitting layer outside the fluorescent light-emitting layer in the plane direction. A liquid crystal display device according to 1.
The liquid crystal display device according to claim 14, wherein the photovoltaic unit is provided such that a light receiving surface thereof faces an end in a surface direction of the fluorescent light emitting layer.
The liquid crystal display device according to claim 1, wherein a diffraction angle of the light beam direction conversion element is 40 ° or more and 70 ° or less.
The liquid crystal display device according to any one of claims 1 to 16, further comprising an antireflection layer disposed on the light beam direction conversion element side of the liquid crystal display panel.
The liquid crystal display device according to any one of claims 1 to 16, further comprising an antireflection layer disposed on the liquid crystal display panel side of the light beam direction conversion element.
17. The liquid crystal display device according to claim 1, further comprising an antireflection layer disposed on the light beam direction conversion element side of the liquid crystal display panel and on the liquid crystal display panel side of the light beam direction conversion element. A liquid crystal display device according to 1.
20. The liquid crystal display device according to claim 1, wherein a difference between an extraordinary refractive index ne and an ordinary refractive index no of the nematic liquid crystal material included in the liquid crystal region is 0.1 or more and 0.3 or less. .
21. The liquid crystal display device according to claim 1, wherein the liquid crystal region does not contain a chiral agent.
The liquid crystal display device according to any one of claims 1 to 21, wherein the dielectric anisotropy of the nematic liquid crystal material is positive.