JPH10333138A - Liquid crystal display element and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display element which can obtains a light display and to provide an electronic equipment incorporated with the element. SOLUTION: As the liquid crystal layer 14 of a liquid crystal cell 10, a guest- host liquid crystal layer 14 is used which has dichroic pigment 16 mixed with base liquid crystal molecules 15 and dispersed. A diffusion plate 40, a polarization splitter 50, a color filter 60, and a reflecting plate 70 are provided in this order below the liquid crystal cell 10. As the polarization splitter 50, a polarization splitter is used which reflects linear polarized light in one direction as linear polarized light in the direction and transmits linear polarized light in the other direction orthogonal to the former direction as linear polarized light in the latter direction. Consequently, linear polarized light perpendicular to this paper surface is projected to outside the liquid crystal display element 1 when a voltage is applied and not applied, so a light display is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and an electronic apparatus, and more particularly to a reflection type liquid crystal display element and an electronic apparatus incorporating the same.

[0002]

2. Description of the Related Art A conventional liquid crystal display device using a TN (Twisted Nematic) liquid crystal or an STN (Super-Twisted Nematic) liquid crystal employs a structure in which this liquid crystal layer is sandwiched between two polarizing plates. Therefore, the efficiency of light utilization is low, and particularly when it is of a reflection type, a dark display is caused, which is a problem.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a liquid crystal display device capable of obtaining a bright display.

[0004]

According to a first aspect of the present invention, there is provided a guest host liquid crystal layer, and polarization splitting means disposed on one side of the guest host liquid crystal layer. The linearly polarized light component in the first predetermined direction is transmitted to the side opposite to the guest host liquid crystal layer, and the linearly polarized light component in the second predetermined direction orthogonal to the first predetermined direction is converted into the guest light. Reflects to the host liquid phase side,
The polarization splitting means capable of emitting linearly polarized light in the first predetermined direction to the guest host liquid crystal layer side with respect to light incident from the opposite side to the guest host liquid crystal layer; An optical element disposed on the side opposite to the guest host liquid crystal layer, wherein the optical element emits predetermined light toward the polarization separation unit with respect to light from the polarization separation unit side. A liquid crystal display device is provided.

In this liquid crystal display element, of the light incident from the guest host liquid crystal layer side, a linearly polarized light component in a first predetermined direction is transmitted to the side opposite to the guest host liquid crystal layer,
A polarization separating unit is used for reflecting a linearly polarized light component in a second predetermined direction orthogonal to the first predetermined direction to the guest host liquid crystal layer side, and the polarization separating unit is opposite to the guest host liquid crystal layer. An optical element that emits predetermined light toward the polarization separation means with respect to light from the polarization separation means side is disposed in the second predetermined direction of the light transmitted through the guest host liquid crystal layer. The light of the linearly polarized light component is reflected by the polarization separating means without reaching the optical element and reaches the guest-host liquid crystal layer, and the light of the linearly polarized light component in the first predetermined direction is transmitted through the polarization separating means and becomes an optical element. When the optical element is irradiated with light, predetermined light is emitted from the optical element, and the light passes through the polarization splitting means again and reaches the guest-host liquid crystal layer.

As described above, the polarized light separating means used here transmits the light of the linearly polarized light component in the first predetermined direction from the guest host liquid crystal side, and transmits the light of the second predetermined direction orthogonal to the first predetermined direction. Since the polarization separation is performed by reflecting the light of the linearly polarized light component in a predetermined direction, the polarized light is transmitted by transmitting the linearly polarized light component in one direction and absorbing the other linearly polarized light component orthogonal to the one linearly polarized light component. Compared with a conventional display element using a polarizing plate for separation, a bright display is obtained because reflected light of a linearly polarized component in the second predetermined direction is used.

Further, in this liquid crystal display device, since the guest-host liquid crystal layer is used, the linearly polarized light component in one direction of the light incident on the guest-host liquid crystal layer is applied when a voltage is applied and when no voltage is applied. At any time, the light passes through the guest-host liquid crystal layer, and the linearly polarized light component in the other direction orthogonal to the one direction is transmitted through the guest-host liquid crystal layer when a voltage is applied, for example, in the case of horizontal alignment, and When no voltage is applied, the light is absorbed by the dichroic dye of the guest-host liquid crystal layer.In the case of vertical alignment, the light passes through the guest-host liquid crystal layer when no voltage is applied, and when the voltage is applied, it is absorbed by the dichroic dye of the guest-host liquid crystal layer. It can be made to be absorbed. As described above, the transmission state of the linearly polarized light component in the other direction can be controlled by the guest-host liquid crystal layer itself. Therefore, it is not necessary to provide any further polarization separation means on the side opposite to the above-mentioned polarization separation means, and a bright display can be obtained.
Furthermore, since the light of the linearly polarized light component in the one direction passes through the guest-host liquid crystal layer both when a voltage is applied and when no voltage is applied, the guest-host liquid crystal layer and the polarization separation unit are separated by a polarization separation unit. By disposing the linearly polarized light component in the second predetermined direction reflected by the guest-host liquid crystal layer both when a voltage is applied and when no voltage is applied, the second predetermined direction can be obtained. A bright display is obtained by the light of the linearly polarized light component.

According to the second aspect, the polarization separating means converts the linearly polarized light component in the first predetermined direction in the light incident from the guest-host liquid crystal layer side into the first predetermined direction. The light is transmitted as linearly polarized light on the side opposite to the guest host liquid crystal layer, and the linearly polarized light component in the second predetermined direction orthogonal to the first predetermined direction is converted into linearly polarized light in the second predetermined direction. Reflects to the host liquid crystal layer side,
The linearly polarized light component in the first predetermined direction out of the light incident from the opposite side to the guest host liquid crystal layer is emitted to the guest host liquid crystal layer side as the linearly polarized light in the first predetermined direction, and the second 2. A liquid crystal display device according to claim 1, wherein said polarization separation means reflects a linearly polarized light component in a predetermined direction as linearly polarized light in said second predetermined direction to a side opposite to said guest host liquid crystal layer. Provided.

According to a third aspect of the present invention, the polarized light separating means is a laminate in which a plurality of layers are laminated in close contact with each other, and the plurality of layers have a refractive index between adjacent layers. 3. The laminate according to claim 1, wherein the laminates are equal in a third predetermined direction and different in a fourth predetermined direction orthogonal to the third predetermined direction.
There is provided a liquid crystal display device as described above.

In the polarized light separating means having such a configuration, the light of the linearly polarized light component in the third predetermined direction out of the light incident on one main surface of the polarized light separating means from the laminating direction is the light The light of the linearly polarized light component in the fourth predetermined direction orthogonal to the third predetermined direction is transmitted as the light of the linearly polarized light in the third predetermined direction to the other main surface on the opposite side. Is reflected as the linearly polarized light, and the light of the linearly polarized light component in the third predetermined direction out of the light incident on the other main surface of the polarization separation means from the laminating direction is the third polarized light. The light of the linearly polarized light component of the fourth predetermined direction, which is transmitted as the linearly polarized light of the predetermined direction to the one main surface side on the opposite side and is orthogonal to the third predetermined direction, is the fourth linearly polarized light. Is reflected as linearly polarized light.

According to a fourth aspect of the present invention, the guest host liquid crystal layer receives the first light from the first side of the guest host liquid crystal layer when a voltage is applied or when no voltage is applied. A linearly polarized light in a fifth predetermined direction can be emitted from a second side opposite to the side, and a straight line in the fifth predetermined direction from the first side with respect to light incident from the second side. 4. The guest-host liquid crystal layer capable of emitting polarized light and absorbing linearly polarized light in a sixth predetermined direction orthogonal to the fifth predetermined direction. A liquid crystal display device according to any one of the above.

Preferably, the fifth predetermined direction substantially coincides with the second predetermined direction.

According to a fifth aspect of the present invention, there is provided the liquid crystal display device according to any one of the first to fourth aspects, wherein the optical element is a color filter.

According to a sixth aspect of the present invention, there is further provided any one of the first to fifth aspects, further comprising a reflecting means disposed on a side of the optical element opposite to the polarization separating means. A liquid crystal display device is provided.

By providing the reflecting means as described above,
The display based on the light from the optical element can be brightened.

According to a seventh aspect of the present invention, there is provided the liquid crystal display device according to any one of the first to sixth aspects, further comprising a light diffusing means.

With this configuration, the display state based on the light reflected from the polarization splitting means can be made white.

Further, according to claim 8, claims 1 to 7 are provided.
An electronic device characterized by incorporating the liquid crystal display element according to any one of the above.

[0019]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view for explaining a liquid crystal display device and a mobile phone according to one embodiment of the present invention, and FIG. 2 is used in the liquid crystal display device according to one embodiment of the present invention. It is a schematic perspective view for explaining a polarization separator,
FIG. 3 is a schematic exploded cross-sectional view for explaining a liquid crystal display device according to one embodiment of the present invention.

As shown in FIG. 1, in a mobile phone 2 according to an embodiment of the present invention, a liquid crystal display element 1 is provided in a mobile phone body case 4 having a transparent cover 3, and the display of the liquid crystal display element 1 is performed. Can be externally observed through the transparent cover 3.

As shown in FIG. 3, the liquid crystal display element 1 of the present embodiment uses a liquid crystal cell 10 having a guest host liquid crystal layer 14. Above the liquid crystal cell 10, a polarizing plate, a polarization separator described later, and the like are not provided. On the lower side of the liquid crystal cell 10, a diffusion plate 40, a polarization separator 50, a color filter 60, and a reflection plate 70 are provided in this order.

In the liquid crystal cell 10, a guest-host liquid crystal layer 14 is sealed in a cell constituted by two glass substrates 11, 12 and a sealing member 13. In the guest host liquid crystal layer 14, the dichroic dye 16 is mixed and dispersed in the base liquid crystal molecules 15 and is in a horizontal alignment state.

Next, the polarization separator 50 used in the liquid crystal display element 1 of the present embodiment will be described with reference to FIG.

The polarization splitter 50 has two different layers 51.
(A layer) and 52 (B layer) have a structure in which a plurality of layers are alternately laminated. The refractive index (nAX) in the X direction of the A layer 51 is different from the refractive index (nAY) in the Y direction. The refractive index (nBX) in the X direction and the refractive index (nBY) in the Y direction of the B layer 52 are equal. Further, the refractive index (nAY) of the A layer 51 in the Y direction and the B layer 5
1 is equal to the refractive index (nBY) in the Y direction.

Accordingly, of the light incident on the polarization separator 50 from a direction perpendicular to the upper surface 55 of the polarization separator 50, linearly polarized light in the Y direction passes through the polarization separator 50 and
6 is emitted as linearly polarized light in the Y direction. Conversely, linearly polarized light in the Y direction among light incident on the polarization separator 50 from a direction perpendicular to the lower surface 56 of the polarization separator 50 passes through the polarization separator 50 and is linearly polarized in the Y direction from the upper surface 56. Out.

On the other hand, the thickness of the A layer 51 in the Z direction is t
Assuming that the thickness of the A and B layers 52 in the Z direction is tB and the wavelength of the incident light is λ,

[0028]

(Equation 1)

With this arrangement, the linearly polarized light in the X direction among the light having the wavelength λ and incident on the polarization separator 50 from a direction perpendicular to the upper surface 55 of the polarization separator 50 is The light is reflected by the polarization separator 50 as linearly polarized light in the X direction. Further, among the light having the wavelength λ and incident on the polarization separator 50 from a direction perpendicular to the lower surface 56 of the polarization separator 50, the linearly polarized light in the X direction is converted into a linear light in the X direction by the polarization separator 50. It is reflected as polarized light.

The thickness t of the A layer 51 in the Z direction
By varying the thickness tB of the A and B layers 52 in the Z direction so that the above equation (1) is satisfied over various wavelength ranges of visible light, not only a single color but also a wide range of white light can be obtained. A linearly polarized light in the X direction is reflected as linearly polarized light in the X direction, and a linearly polarized light in the Y direction is transmitted as linearly polarized light in the Y direction.

Such a polarized light separator is disclosed in International Publication No. WO95 / 17692, and the present embodiment also uses the polarized light separator disclosed in this publication.

Next, the operation of the liquid crystal display element 1 of the present embodiment will be described with reference to FIG. No voltage application part 2 on left side
Reference numeral 20 denotes a voltage application unit on the right side.

In the voltage application section 210 on the right side, when natural light of external light enters the liquid crystal display element 1, of the natural light, light 211 of a linearly polarized component in a direction perpendicular to the paper surface passes through the guest-host liquid crystal layer 14. After that, the light passes through the diffusion plate 40 to reach the polarization separator 50, is reflected by the polarization separator 50, and is again transmitted to the diffusion plate 40 and the guest host liquid crystal layer 14.
, And is emitted to the outside of the liquid crystal display element 1 to be emitted light 212 traveling toward the observation side. The light 213 of the linearly polarized component in the direction parallel to the paper surface passes through the guest-host liquid crystal layer 14, then passes through the diffusion plate 40 and reaches the polarization separator 50. Then, the linearly polarized light reaching the polarization separator 50 in a direction parallel to the paper surface passes through the polarization separator 50 as linearly polarized light in a direction parallel to the paper surface. A part of the linearly polarized light in the direction parallel to the paper surface that has passed through the polarization separator 50 is reflected by the color filter 60, and then transmitted through the polarization separator 50 as linearly polarized light in the direction parallel to the paper surface. ,
The light passes through the diffusion plate 40 and the guest-host liquid crystal layer 14 and is emitted to the outside of the liquid crystal display element 1 to be emitted light 214 traveling toward the observation side. Another part of the linearly polarized light transmitted through the polarization separator 50 in the direction parallel to the paper is transmitted through the color filter 60 while being absorbed by the color filter 60, reflected by the reflection plate 70, and then re-colored. Color filter 6 while being absorbed by filter 60
0, and then passes through the polarization separator 50 as linearly polarized light in a direction parallel to the plane of the paper, and then passes through the diffusion plate 40 and the guest-host liquid crystal layer 14 and exits outside the liquid crystal display element 1. The emitted light 214 travels toward the observation side.

In the left non-voltage application section 220, when natural light of external light enters the liquid crystal display element 1, of the natural light, light 221 of a linearly polarized component in a direction perpendicular to the paper surface passes through the guest-host liquid crystal layer 14. After that, the light passes through the diffusion plate 40 and reaches the polarization separator 50, is reflected by the polarization separator 50, and is again transmitted to the diffusion plate 40 and the guest-host liquid crystal layer 1.
4 and is emitted to the outside of the liquid crystal display element 1 to be emitted light 222 traveling toward the observation side. The light 223 of the linearly polarized component in the direction parallel to the paper surface is absorbed by the dichroic dye 16 of the guest-host liquid crystal layer 14, and the color of the dichroic dye 16 is displayed.

Therefore, when a voltage is applied, the polarization separator 50
Outgoing light 212 based on the light reflected by the light and outgoing light 214 that is colored and emitted by the color filter 60.
And output light 222 based on the light reflected by the polarization separator 50 when no voltage is applied.
And light that has been absorbed by the dichroic dye 16 and has become light of a predetermined wavelength component.

As described above, in both the case of applying a voltage and the case of not applying a voltage, since the emitted light 212 or 222 based on the light reflected by the polarization separator 50 exists, a bright display is obtained.

Since the diffusion plate 40 is provided between the polarization separator 50 and the guest host liquid crystal layer 14, the light reflected from the polarization separator 50 changes from a mirror surface to a white state. Therefore, when a voltage is applied, a bright color display colored by the color filter 60 is obtained, and when no voltage is applied, a bright display with the color of the dichroic dye 16 is obtained.

Further, since the reflecting plate 70 is provided, the emitted light 21 of the color colored by the color filter 60 is provided.
4 becomes brighter.

In the above description, the case where the guest-host liquid crystal layer 14 is horizontally oriented has been described as an example. However, when the guest-host liquid crystal layer 14 is vertically oriented, the linear polarization component Light is transmitted through the guest-host liquid crystal layer 14 when no voltage is applied, and is absorbed by the dichroic dye 16 of the guest-host liquid crystal layer 14 when a voltage is applied. The same is true.

[0040]

According to the present invention, there are provided a liquid crystal display device capable of obtaining a bright display and an electronic device incorporating the same.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating a liquid crystal display device and a mobile phone according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view for explaining a polarization separator used in the liquid crystal display device according to one embodiment of the present invention.

FIG. 3 is a schematic exploded cross-sectional view illustrating a liquid crystal display device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display element 2 ... Cellular phone 3 ... Transparent cover 4 ... Cellular phone main body case 10 ... Liquid crystal cell 11, 12 ... Glass substrate 14 ... Guest host liquid crystal layer 15 ... Base liquid crystal molecule 16 ... Dichroic dye 40 ... Diffusion plate Reference Signs List 50: polarization separator 60: color filter 70: reflector 210: voltage application unit 211, 213, 221, 223 ... incident light 212, 214, 222 ... output light 220: voltage non-application unit

Claims (8)

[Claims] 1. A guest-host liquid crystal layer, comprising: a polarization separation unit disposed on one side of the guest-host liquid crystal layer; Transmitting a linearly polarized light component to a side opposite to the guest host liquid crystal layer and reflecting a linearly polarized light component in a second predetermined direction orthogonal to the first predetermined direction toward the guest host liquid crystal layer; The polarization separating means capable of emitting linearly polarized light in the first predetermined direction to the guest host liquid crystal layer side with respect to light incident from the side opposite to the liquid crystal layer; and the guest host liquid crystal with respect to the polarization separating means. An optical element arranged on the side opposite to the layer, wherein the optical element emits predetermined light toward the polarization separation unit with respect to light from the polarization separation unit side. LCD display Child. 2. The guest-host liquid crystal device according to claim 1, wherein said polarization separation means converts the linearly polarized light component in the first predetermined direction of the light incident from the guest-host liquid crystal layer side into the first predetermined direction as linearly polarized light. And transmitting the linearly polarized light component in the second predetermined direction perpendicular to the first predetermined direction to the guest host liquid crystal layer side as linearly polarized light in the second predetermined direction. Emitting the linearly polarized light component in the first predetermined direction from the light incident from the side opposite to the guest host liquid crystal layer to the guest host liquid crystal layer side as linearly polarized light in the first predetermined direction; 2. A liquid crystal display element according to claim 1, wherein said polarization separation means reflects the linearly polarized light component in the second predetermined direction as the linearly polarized light in the second predetermined direction to the side opposite to the guest host liquid crystal layer. . 3. The polarized light separating means according to claim 1, wherein said polarized light separating means is a laminated body in which a plurality of layers are laminated in close contact with each other, and said plurality of layers have a refractive index of a third predetermined value between adjacent layers. A fourth direction which is equal in the direction and is orthogonal to the third predetermined direction.
The liquid crystal display device according to claim 1, wherein the laminates are different in a predetermined direction. 4. The guest-host liquid crystal layer has a second surface facing the first side with respect to light incident from the first side of the guest-host liquid crystal layer when a voltage is applied or no voltage is applied. From the second side, and emits linearly polarized light in a fifth predetermined direction.
The guest-host liquid crystal layer capable of emitting linearly polarized light in the fifth predetermined direction from the side and absorbing linearly polarized light in a sixth predetermined direction orthogonal to the fifth predetermined direction. The liquid crystal display device according to any one of claims 1 to 3, wherein 5. The liquid crystal display device according to claim 1, wherein said optical element is a color filter. 6. The liquid crystal display device according to claim 1, further comprising a reflection unit disposed on a side opposite to the polarization separation unit with respect to the optical element. 7. The liquid crystal display device according to claim 1, further comprising a light diffusing means. 8. An electronic apparatus incorporating the liquid crystal display element according to claim 1.