JP2003322847A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display which performs both of reflective display using external light and transmissive display using illuminating light from a light source and by which bright and excellent display without coloring is obtained in both of the reflective display and the transmissive display. <P>SOLUTION: An absorption polarization plate 6 is arranged on the front side of a liquid crystal element 1 formed by providing a liquid crystal layer between a front substrate 2 on the observation side of display and a rear substrate 3. On the rear side of the liquid crystal display 1, a reflective polarization plate 7 that reflects light of one polarization component and transmits the other component among the two linearly polarized components of light emitted to the rear side after transmitting the liquid crystal display 1. Further, a light absorption layer 8 is arranged on the rear side of the reflective polarization plate 7, and a surface light source 10 that transmits light made incident from the sides of the liquid crystal element 1 and the reflective polarization plate 7 and emits the illuminating light toward the reflective polarization plate 7 is arranged between the liquid crystal element 1 and the reflective polarization plate 7. <P>COPYRIGHT: (C)2004,JPO

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 for displaying both reflective display using external light which is light of the external environment and transmissive display using illumination light from a light source.

[0002]

2. Description of the Related Art A reflective / transmissive liquid crystal display device for displaying both a reflective display utilizing external light which is the light of an external environment and a transmissive display utilizing illumination light from a light source is conventionally known.
A liquid crystal element, in which a liquid crystal layer for controlling the polarization state of transmitted light according to an applied electric field is provided between a front substrate which is an observation side of the display and a rear substrate which faces the front substrate, Of the two linearly polarized light components of the incident light which are orthogonal to each other, a front absorption plate and a rear absorption plate that absorb the light of one polarization component and transmit the other polarization component are arranged, and the rear side The semi-transmissive reflective film is arranged on the rear side of the absorption polarizing plate and the surface light source is arranged on the rear side.

[0003]

However, in the above-mentioned conventional reflective / transmissive liquid crystal display device, in the reflective display utilizing external light, the semi-transmissive reflective film enters from the front side which is the viewing side of the display. The light reflected by and emitted again to the front side is absorbed by the front and rear absorption polarizing plates a total of four times in the process, and the intensity of the emitted light to the front side is greater than the intensity of the incident light from the front side. And the transmitted light is colored due to the wavelength dependency of the light absorption characteristics of the absorption polarizing plate in the process of passing through the absorption polarizing plate four times, so that the display in the reflective display is dark and the display is I have the problem of coloring.

The present invention is a reflective display utilizing external light,
It is possible to perform both a display and a transmissive display that uses illumination light from a light source, and it is possible to obtain a good display that is bright and has no color band in both the reflective display and the transmissive display. It is intended to provide a liquid crystal display device.

[0005]

The liquid crystal display device according to the present invention transmits a transmitted light in accordance with an electric field applied between a front substrate which is a viewing side of a display and a rear substrate which faces the front substrate. And a liquid crystal element provided with a liquid crystal layer for controlling the polarization state, and which absorbs light of one polarization component of two linear polarization components of incident light which are arranged in front of the liquid crystal element and are orthogonal to each other, An absorption polarizing plate that transmits the polarized component of
Of the two linearly polarized light components, which are arranged on the rear side of the liquid crystal element and transmitted through the liquid crystal element and emitted to the rear side, one of the linearly polarized light components is reflected, and the other polarized light component is reflected. A reflective polarizing element that transmits light, a light absorbing layer that is disposed further behind the reflective polarizing element, and is disposed between the liquid crystal element and the reflective polarizing element, from the liquid crystal element side and the reflective polarizing element side. And a surface light source that transmits incident light and emits illumination light toward the reflective polarization element.

This liquid crystal display device performs a reflective display using external light which is the light of the external environment and a transmissive display using the illumination light from the surface light source. In the reflective display, Light incident from the front side, which is the viewing side of the display,
It is linearly polarized by the absorption polarizing plate, and the polarization state is controlled by the liquid crystal layer of the liquid crystal element to enter the reflective polarizing element from the front side thereof, and out of the light, the polarized component reflected by the reflective polarizing element. Light is transmitted through the liquid crystal element and the absorption polarizing plate and emitted to the front side, and the light of the polarization component transmitted through the reflective polarizing element is transmitted through the surface light source and is absorbed by the light absorbing film.

Further, in the case of transmissive display utilizing the illumination light from the surface light source, the illumination light emitted from the surface light source toward the reflective polarization element is incident on the reflective polarization element from the rear side, Of the light, the light of the polarization component that has passed through the reflective polarization element is incident on the liquid crystal element from the rear side, and the polarization state is controlled by the liquid crystal layer of the liquid crystal element and is incident on the absorption polarizing plate, Of the light, the light of one polarization component passes through the absorption polarizing plate and is emitted to the front side,
The light of the other polarization component is absorbed by the absorption polarizing plate.

According to this liquid crystal display device, it is possible to perform both a reflective display utilizing external light and a transmissive display utilizing the illumination light from the surface light source, and also in the reflective display. Even in the transmissive display, the absorption of light by the polarizing plate is only the absorption by the single absorption polarizing plate arranged on the front side of the liquid crystal element, and therefore the decrease in the intensity of the emitted light with respect to the intensity of the incident light is small. In addition, since there is almost no coloration of transmitted light due to the wavelength dependence of the light absorption characteristics of the absorption polarizing plate, it is possible to obtain a bright and good colorless display in both reflective display and transmissive display. .

As described above, the liquid crystal display device of the present invention is
An absorption polarizing plate is arranged on the front side of a liquid crystal element in which a liquid crystal layer is provided between the front side substrate and the rear side substrate which are the viewing side of the display,
Of the two linearly polarized light components of the light that has passed through the liquid crystal element and is emitted to the rear side, the light of one polarization component is reflected and the other polarization component is transmitted to the rear side of the liquid crystal element. A reflective polarizing element is arranged, and a light absorbing layer is further arranged on the rear side of the reflective polarizing element, and the light is incident between the liquid crystal element side and the reflective polarizing element side between the liquid crystal element and the reflective polarizing element. By arranging a surface light source that transmits light and emits illumination light toward the reflective polarization element, both of a reflective display that uses external light and a transmissive display that uses illumination light from the surface light source. In addition, it is possible to perform display, and it is possible to obtain a good display that is bright and has no banding in both the reflective display and the transmissive display.

In this liquid crystal display device, the absorption polarization plate and the reflection polarization element have a transmission axis parallel to the vibration plane of the transmission light of the absorption polarization plate and a reflection axis parallel to the vibration plane of the reflection light of the reflection polarization element. The axes are preferably arranged substantially parallel or orthogonal to each other.

The light absorption layer may be an absorption film that absorbs light in a wavelength band of at least a part of the visible light band, or one of two linearly polarized light components of incident light which are orthogonal to each other. It may be an absorption polarizing plate that absorbs the light of and transmits the other polarization component. When the light absorption layer is an absorption polarizing plate, the absorption axis parallel to the vibrating surface of the absorbed light is It is preferably arranged substantially parallel to the transmission axis.

[0012]

1 to 3 show a first embodiment of the present invention. FIG. 1 is an exploded perspective view of a liquid crystal display device,
2 is a cross-sectional view of the liquid crystal display device without hatching, and FIG. 3 is a schematic view showing a light transmission path of the liquid crystal display device.

As shown in FIGS. 1 and 2, the liquid crystal display device of this embodiment includes a liquid crystal element 1, a sheet of absorption polarizing plate 6 arranged in front of the liquid crystal element 1, and the liquid crystal element. 1
The reflective polarizing element 7 disposed on the rear side of the reflective polarizing element 7, the light absorbing layer 8 disposed on the rear side of the reflective polarizing element 7, and the liquid crystal element 1
And a surface light source 10 disposed between the reflective polarization element 7 and the reflective polarization element 7.

The liquid crystal element 1 is provided with a transmitted light depending on an electric field applied between a front transparent substrate 2 which is a display observing side and a rear transparent substrate 3 which faces the front substrate 2. A liquid crystal layer 5 (see FIG. 2) for controlling the polarization state is provided, and the front substrate 2 and the rear substrate 3 are bonded to each other via a frame-shaped sealing material 4. , 3 is provided with the liquid crystal layer 5 in a region surrounded by the sealing material 4.

Although not shown in the figure, on the inner surfaces of the substrates 2 and 3 before and after the liquid crystal element 1, transparent electrodes forming a plurality of pixels arranged in a matrix by regions facing each other are provided. It is provided and an alignment film is provided thereon.

The liquid crystal element 1 is an active matrix liquid crystal element having, for example, a TFT (thin film transistor) as an active element, and is arranged in a matrix in the row direction and the column direction on the inner surface of one substrate, for example, the rear substrate 3. A plurality of pixel electrodes, a plurality of TFTs respectively connected to these pixel electrodes, a plurality of gate wirings for supplying gate signals to the TFTs in each row, and a plurality of TFTs for supplying data signals to the TFTs in each column. A plurality of colors, such as red and green, are formed on the inner surface of the front substrate 2, which is the other substrate, provided with data wirings (none of which is shown) so as to face the pixel electrodes. A color filter of three colors of blue and a single film-shaped counter electrode (not shown) formed thereon are provided.

Further, the liquid crystal element 1 is of a TN (twisted nematic) type, and the liquid crystal layer 5 thereof is
The liquid crystal molecules are substantially 90 ° between the front and rear substrates 2 and 3.
It consists of nematic liquid crystal with positive dielectric anisotropy, which is twist-aligned at the twist angle of.

In FIG. 1, an arrow 2a indicates the liquid crystal element 1
Direction of liquid crystal molecules in the vicinity of the front substrate 2 of the arrow 3,
Reference symbol a denotes a liquid crystal molecule alignment direction in the vicinity of the rear substrate 3, and liquid crystal molecule alignment direction 2a in the vicinity of the front substrate 2 is substantially one direction with respect to the horizontal axis x of the screen of the liquid crystal display device. And the liquid crystal molecule alignment direction 3a in the vicinity of the rear substrate 3 is substantially 45 ° in the other direction with respect to the horizontal axis x, and the liquid crystal molecules of the liquid crystal layer 5 are From the rear substrate 3 to the front substrate 2, as shown in FIG.
The twist orientation is substantially 90 ° in the twist direction indicated by the broken line arrow.

The absorption polarizing plate 6 arranged on the front side of the liquid crystal element 1 absorbs one polarization component of the two linear polarization components of the incident light which are orthogonal to each other and transmits the other polarization component. It is a polarizing plate and has a transmission axis 6a parallel to the vibration plane of transmitted light and an absorption axis (not shown) parallel to the vibration plane of absorbed light.

The absorption polarizing plate 6 has its transmission axis 6a substantially parallel or orthogonal to the liquid crystal molecule orientation direction 2a in the vicinity of the front substrate 2 of the liquid crystal element 1 (orthogonal in the figure). 1 is attached to the outer surface of the front substrate 2.

The reflective polarization element 7 arranged on the rear side of the liquid crystal element 1 reflects one polarization component of the two linear polarization components of the incident light which are orthogonal to each other, and the other polarization component. Is a reflective polarizing plate that transmits the light of, and has a transmission axis 7a parallel to the vibration surface of the transmitted light and a reflection axis 7b parallel to the vibration surface of the reflected light.

The reflection axis 7b of the reflection polarizing plate 7 is substantially parallel to the transmission axis 6a of the absorption polarizing plate 6, and the transmission axis 7a is substantially the same as the transmission axis 6a of the absorption polarizing plate 6. They are arranged on the rear side of the liquid crystal element 1 so as to be orthogonal to each other.

Further, the light absorption layer 8 arranged on the rear side of the reflective polarizing plate 7 is an absorption film for absorbing light in at least a part of the visible light band, for example, all of the visible light band. It is composed of an absorption film that absorbs light, and is attached to the rear surface of the reflective polarizing plate 7.

Further, the surface light source 10 transmits the light incident from one surface and the other surface, respectively, and outputs the incident light from the end surface from the one surface, and the end surface of the light guide plate 11. Light-emitting element 13 provided to face
It consists of

The surface light source 10 used in this embodiment is
A plurality of light emitting elements 13 including LEDs (light emitting diodes)
Is arranged so as to face the end surface of the light guide plate 11, but the light emitting element arranged so as to face the end surface of the light guide plate 11 may be a straight-tube cold cathode tube or the like.

The surface light source 10 transmits the light incident from one surface of the light guide plate 11, emits the light from the other surface of the light guide plate 11, and emits the light incident from the other surface of the light guide plate 11. The illumination light emitted from the light emitting element 13 is made incident on the light guide plate 11 from its end face while being transmitted and emitted from one surface of the light guide plate 11.
The light guide plate 11 is guided through the inside of the light guide plate 11 while being totally reflected at an interface between one and the other surfaces of the light guide plate 11 and the outside air (air), and one surface (hereinafter referred to as an illumination light emission surface) 11a of the light guide plate 11.
The light that has traveled toward the other surface of the light guide plate 11 is directed to the other surface of the light guide plate 11 in a direction in which the angle with respect to the normal line of the light guide plate becomes smaller. A plurality of groove-shaped recesses 12 for reflecting and emitting from the illumination light emitting surface 11a are formed in parallel with the end surface of the light guide plate 11.

Although the pitch of the plurality of groove-shaped recesses 12 is greatly exaggerated in the drawing, the groove-shaped recesses 1
2 denotes a pixel pitch of the liquid crystal element 1 (100 μm to 20 μm).
The pitch is smaller than about 0 μm).

In the surface light source 10, the illumination light emitting surface 11a of the light guide plate 11 is opposed to the reflection polarizing plate 7 between the liquid crystal element 1 and the reflection polarizing plate 7, and the liquid crystal element is formed. It is arranged so that the light incident from the first side and the reflective polarizing plate 7 side is transmitted and the illumination light is emitted toward the reflective polarizing element 7.

In this liquid crystal display device, under the environment where the outside light having a sufficient brightness is obtained, the reflection display using the outside light which is the light of the outside environment is performed, and the outside light having a sufficient brightness cannot be obtained. At this time, the illumination light is emitted from the surface light source 10 and the transmissive display utilizing the illumination light is performed.

In the case of the reflective display, external light (non-polarized light) incident from the front side which is the viewing side of the display is linearly polarized by the absorption polarizing plate 6 and further by the liquid crystal layer 5 of the liquid crystal element 1. The polarization state is controlled and enters the reflection polarizing plate 7 from the front side thereof, and out of the light, the reflection polarizing plate 7
The light of the polarization component reflected by is transmitted through the liquid crystal element 1 and the absorption polarization plate 6 and emitted to the front side, and the light of the polarization component transmitted through the reflection polarization plate 7 is transmitted through the surface light source 10. Is absorbed by the light absorption layer 8.

That is, in the case of the reflective display, as shown by the solid line arrow in FIG. 3, of the two linearly polarized light components orthogonal to each other of the light incident from the front side, which is the observation side of the display, the absorption polarization plate. Light having a polarization component parallel to the absorption axis 6 (not shown) is absorbed by the absorption polarizing plate 16, and light having a polarization component parallel to the transmission axis 6a of the absorption polarizing plate 6 passes through the absorption polarizing plate 6. , The transmission axis 6 of the absorption polarizing plate 6
The linearly polarized light S parallel to a is incident on the liquid crystal element 1.

Linearly polarized light S incident on the liquid crystal element 1
Emits to the rear side of the liquid crystal element 1 under the birefringence action of the liquid crystal layer 5 according to the alignment state of the liquid crystal molecules which is changed by the electric field applied between the electrodes of the liquid crystal element 1.

The alignment state of the liquid crystal molecules when no electric field is applied between the electrodes of the liquid crystal element 1 (V = 0) is substantially twist alignment with a twist angle of 90 °. The linearly polarized light S transmitted through the absorption polarizing plate 6 and incident on the liquid crystal element 1 is rotated by the birefringent action of the liquid crystal layer 5 as shown by the solid arrow on the right side of FIG. The linearly polarized light P rotated by 90 ° is emitted to the rear side of the liquid crystal element 1, is transmitted through the light guide plate 11 of the surface light source 10, and is incident on the reflection polarization plate 7.

The reflection axis 7b of the reflection polarizing plate 7 is substantially parallel to the transmission axis 6a of the absorption polarizing plate 6, and the transmission axis 7a is substantially the same as the transmission axis 6a of the absorption polarizing plate 6. Since they are arranged orthogonally to each other, the linearly polarized light P emitted to the rear side of the liquid crystal element 1 and incident on the reflection polarizing plate 7 is transmitted through the reflection polarizing plate 7 and absorbed by the light absorption layer 8. , The display of that area becomes black and dark.

On the other hand, when an electric field is applied between the electrodes of the liquid crystal element 1 to vertically orient the liquid crystal molecules substantially perpendicular to the surfaces of the substrates 2 and 3 (V> Vth), the absorption polarizing plate is applied. The linearly polarized light S that has passed through 6 and has entered the liquid crystal element 1 passes through the liquid crystal element 1 without changing the polarization state and is emitted to the rear side, as indicated by the solid arrow on the left side of FIG.

The linearly polarized light S emitted to the rear side of the liquid crystal element 1 passes through the light guide plate 20, enters the reflection polarization plate 7, and is reflected by the reflection polarization plate 7.

The linearly polarized light S reflected by the reflective polarizing plate 7 is again transmitted through the light guide plate 11 and re-enters the liquid crystal element 1 from the rear side thereof, without changing the polarization state of the liquid crystal element 1. The light is transmitted, further transmitted through the absorption polarizing plate 6 and emitted to the front side, and the display in that region becomes a bright display (colored display of the color of the color filter provided in the liquid crystal element 1).

In the case of transmissive display using the illumination light from the surface light source 10, the illumination light (non-polarized light) emitted from the surface light source 10 toward the reflective polarizing plate 7 is the reflected polarized light. The light of the polarization component that has entered the plate 7 from the rear side and has passed through the reflective polarizing plate 7 then enters the liquid crystal element 1 from the rear side, and the liquid crystal layer 5 of the liquid crystal element 1
The polarization state is controlled by the light to enter the absorption polarizing plate 6, and the light of one polarization component of the light is transmitted through the absorption polarizing plate 6 and emitted to the front side, and the light of the other polarization component. Are absorbed by the absorption polarizing plate 6.

That is, during the transmissive display, the light emitting element 13 of the surface light source 10 is turned on, and the light emitting element 13 is turned on.
As shown by the broken line arrow in FIG. 3, the illuminating light from the light enters the light guide plate 11 from its end face and is guided through the light guide plate 11, and most of the light is opposed to the reflective polarizing plate 7. It is emitted from the illumination light emitting surface 11a.

Illumination light emitted from the surface light source 10 (light emitted from the illumination light emission surface 11a of the light guide plate 11) enters the reflection polarization plate 7, and of the light, the reflection light from the reflection polarization plate 7 is reflected. The linearly polarized light S having a polarization component parallel to the axis 7b is reflected by the reflective polarizing plate 7, and the linearly polarized light S is
The light passes through the light guide plate 11 of the surface light source 10 and enters the liquid crystal element 1 from the rear side.

Of the light emitted from the surface light source 10 and incident on the reflection polarizing plate 7, linearly polarized light P having a polarization component parallel to the transmission axis 7a of the reflection polarizing plate 7 is the reflection polarizing plate 7. The light is transmitted through 7 and is absorbed by the absorption polarizing plate 6.

When no electric field is applied between the electrodes of the liquid crystal element 1 (V = 0), the light is emitted from the surface light source 10, reflected by the reflective polarizing plate 7, and then directed to the liquid crystal element 1. The linearly polarized light S incident from the side is rotated by the birefringence effect of the liquid crystal layer 5, and the linearly polarized light P whose vibrating surface is substantially rotated by 90 ° is generated as shown by a broken line arrow on the right side of FIG. Then, the light is emitted to the front side of the liquid crystal element 1 and is absorbed by the absorption polarizing plate 16, and the display in that area becomes a black dark display.

On the other hand, when an electric field is applied between the electrodes of the liquid crystal element 1 to vertically orient the liquid crystal molecules substantially perpendicularly to the substrates 2 and 3 (V> Vth), the surface light source 10 is applied. The linearly polarized light S that is emitted from the liquid crystal layer 1, is reflected by the reflective polarizing plate 7 and is incident on the liquid crystal element 1 from the rear side thereof, causes the liquid crystal layer 5 to have a polarization state as indicated by a broken line arrow on the left side of FIG. The light is transmitted without change, is transmitted through the absorption polarizing plate 6 and is emitted to the front side, and the display in that region becomes a bright display (colored display of the color of the color filter provided in the liquid crystal element 1).

That is, the display of this liquid crystal display device is in the absence of an electric field (V = V) in both reflective display using external light and transmissive display using illumination light from the surface light source 10.
The display of 0) is a dark display, and the display when an electric field is applied (V> Vth) is a normally black display of a bright display.

As described above, in this liquid crystal display device, the absorption polarizing plate 6 is provided in front of the liquid crystal element 1 in which the liquid crystal layer 5 is provided between the front substrate 2 and the rear substrate 3 which are the viewing side of the display. Arranged on the rear side of the liquid crystal element 1, one of the two linearly polarized light components of the light transmitted through the liquid crystal element 1 and emitted to the rear side of the liquid crystal element 1 reflects one polarization component light and reflects the other light. A reflective polarizing plate 7 that transmits a polarized component is disposed, and a light absorbing layer 8 is further disposed behind the reflective polarizing plate 7, and
A surface light source that transmits the light incident from the liquid crystal element 1 side and the reflective polarizing plate 7 side between the liquid crystal element 1 and the reflective polarizing plate 7, and emits illumination light toward the reflective polarizing plate 7. Since 10 is arranged, both reflective display using external light and transmissive display using illumination light from the surface light source 10 can be displayed.

In addition, according to this liquid crystal display device, the absorption of light by the polarizing plate is performed by the single absorption polarizing plate 6 arranged in front of the liquid crystal element 1 in both reflective display and transmissive display. It is only absorption, and therefore the decrease in the intensity of the emitted light with respect to the intensity of the incident light is small, and there is almost no banding of the transmitted light due to the wavelength dependence of the light absorption characteristics of the absorption polarizing plate 6. Also in the case of the transmissive display, it is possible to obtain a good display which is bright and has no banding.

Furthermore, in this embodiment, the liquid crystal element 1 is used.
Liquid crystal molecules are substantially 9 between the front and rear substrates 2 and 3.
A TN type liquid crystal element twist-aligned with a twist angle of 0 ° is used, and the absorption polarizing plate 6 and the reflection polarizing plate 7 are provided with a transmission axis 16a parallel to a vibrating surface of transmitted light of the absorption polarizing plate 6 and the reflection polarization. Since the transmission axis 7a parallel to the vibrating surface of the transmitted light of the plate 7 is disposed substantially orthogonal to each other, it is possible to obtain a high-contrast display both in the reflective display and in the transmissive display. it can.

In the above embodiment, the reflective polarizing plate 7 is used.
Is arranged such that its reflection axis 7b is substantially parallel to the transmission axis 6a of the absorption polarizing plate 6 and the transmission axis 7a is substantially orthogonal to the transmission axis 6a of the absorption polarizing plate 6. The reflection polarizing plate 7 is arranged such that its reflection axis 7b is substantially orthogonal to the transmission axis 6a of the absorption polarizing plate 6, and the transmission axis 7a is substantially parallel to the transmission axis 6a of the absorption polarizing plate 6. In that case, in both the reflective display using external light and the transmissive display using the illumination light from the surface light source 10, the display when there is no electric field (V = 0) is a bright display or an electric field. When the voltage is applied (V> Vth), the display becomes a dark, normally white display.

Further, in the above embodiment, one reflective polarizing element 7 is arranged on the rear side of the liquid crystal element 1. However, as in the second embodiment shown in FIG. 2 on the back
The reflection polarizing plates 7 may be laminated and arranged with the transmission axis 7a and the reflection axis 7b (see FIG. 1) aligned. By doing so, the linearly polarized light reflected by the reflection polarizing plate 7 may be obtained. Linearly polarized light S transmitted through the light S and the reflection polarization plate 7
It is possible to increase the degree of polarization and increase the display contrast.

Further, in the above-mentioned embodiment, the light absorption layer 8 made of an absorption film that absorbs all the light in the visible light band is arranged on the rear side of the reflection polarizing plate 7.
May be a colored absorption film that absorbs light in a part of the visible light wavelength band, and in that case, the dark display at the time of the reflective display utilizing the external light described above is colored by the color of the colored absorption film. It can be a display.

The light absorbing layer arranged on the rear side of the reflective polarizing plate 7 is not limited to an absorbing film that absorbs at least a part of light in the visible light band, and may be an absorbing polarizing plate.

FIG. 5 is an exploded perspective view of a liquid crystal display device showing a third embodiment of the present invention. In this embodiment, two straight lines of incident light which are orthogonal to each other are provided on the rear side of the reflective polarizing plate 7. Of the polarization components, the light absorption layer 9 made of an absorption polarizing plate that absorbs light of one polarization component and transmits the other polarization component.
A transmission axis 9a parallel to the vibrating surface of the transmitted light is substantially orthogonal to a transmission axis 9a parallel to the vibrating surface of the transmitted light of the reflection polarizing plate 7, and absorption parallel to the vibrating surface of the absorbed light. The axis (not shown) is arranged substantially parallel to the transmission axis 9a of the reflective polarizing plate 7.

The liquid crystal display device of this embodiment is similar to that shown in FIG.
The light absorption layer 8 of the liquid crystal display element of the first embodiment shown in FIG. 3 is replaced with a light absorption layer 9 made of an absorption polarizing plate, and other configurations are the same as those of the first embodiment. Therefore, the same description will be omitted by giving the same reference numerals to the drawings.

In the liquid crystal display device of this embodiment, the light absorbing layer 9 made of an absorbing polarizing plate is disposed behind the reflecting polarizing plate 7, and the light absorbing layer 9 made of this absorbing polarizing plate.
Is arranged such that its absorption axis is substantially parallel to the transmission axis 9a of the reflective polarizing plate 7, so that the light transmitted through the reflective polarizing plate 7 is absorbed by the light absorbing layer 9 and external light is absorbed. The dark display used for the reflective display can be made darker than the dark display used for the reflective display in the liquid crystal display device of the first embodiment described above.

Further, in each of the above embodiments, the reflective polarizing plate 7 is used as the reflective polarizing element arranged on the rear side of the liquid crystal element 1. However, the reflective polarizing element has two straight lines of incident light which are orthogonal to each other. Of the polarized light components, as long as it reflects light of one polarized light component and transmits the other polarized light component, it is not limited to the reflective polarizing plate, and, for example, two clockwise and counterclockwise incident light beams can be used.
Of the two circularly polarized light components, at least the incident surface facing the liquid crystal element 1 of a polarization separation film (for example, a cholesteric liquid crystal film) that reflects light of one circularly polarized light component and transmits light of the other circularly polarized light component, A λ / 4 phase difference plate for converting linearly polarized light into circularly polarized light to enter the polarization separation film, and converting the circularly polarized light of the one circularly polarized light component reflected by the polarization separation film into linearly polarized light, and emitting the linearly polarized light. A laminated film may be used.

In the case of the liquid crystal display devices of the first and second embodiments described above, the light absorption layer 8 made of an absorption film that absorbs light in the wavelength band of at least a part of the visible light band is the incident light. In order to absorb light in the absorption wavelength band irrespective of the polarization state, the reflective polarizing element composed of the laminated film has the λ / 4 retardation plate laminated only on the incident surface of the polarized light separating film to separate the polarized light. Even if the circularly polarized light is emitted from the emission surface (the surface facing the light absorption layer 8) of the film, the λ / 4 is formed on each of the incident surface and the emission surface of the polarization separation film.
It is also possible to stack retardation plates and emit linearly polarized light from the emission surface.

On the other hand, in the case of the liquid crystal display device of the third embodiment described above, since the light absorption layer 9 made of the absorption polarizing plate absorbs the light of the linearly polarized light component parallel to the absorption axis 9a thereof, The reflective polarizing element made of a film is preferably one in which the λ / 4 phase difference plate is laminated on each of the entrance surface and the exit surface of the polarization separation film, and linearly polarized light is emitted from the exit surface.

When the reflective polarizing element composed of the laminated film is used, the absorption polarizing plate 6 on the front side of the liquid crystal element 1 and the reflective polarizing element are parallel to the vibration plane of the transmitted light of the absorption polarizing plate 6. The transmission axis 6a and the reflected light of the reflective polarization element (which is reflected by the polarization separation film and is λ / 4 on the incident surface side).
It is preferable that the reflection axis parallel to the vibrating surface of the light that is made into the linearly polarized light by the phase difference plate and is emitted to the front side of the reflective polarization element is substantially parallel or orthogonal to this. Therefore, even in the case of reflective display that uses external light,
Even in the case of transmissive display using the illumination light from the surface light source 10,
A high contrast display can be obtained.

Further, the reflection polarizing plate 8 of the liquid crystal display device of the third embodiment described above is formed of a laminated film in which λ / 4 phase difference plates are laminated on the entrance surface and the exit surface of the polarization separation film. When replacing with a polarizing element, the absorption polarizing plate 6 and the reflection polarizing element are arranged so that the transmission axis 6a of the absorption polarizing plate 6 and the reflection axis of the reflection polarizing element are substantially parallel or orthogonal to each other as described above. The light absorption layer 9 composed of an absorption polarizing plate is arranged, and the absorption axis thereof is transmitted light of the reflective polarization element (transmits through the polarization separation film and has λ /
It is preferable that the light is emitted as a linearly polarized light by the 4 phase plate and emitted to the rear side of the reflective polarizing element) substantially parallel to the transmission axis parallel to the vibrating surface of the reflective polarizing element. It is possible to obtain a high-contrast display in both reflective display using external light and transmissive display using illumination light from the surface light source 10.

The liquid crystal display device of each of the above-mentioned embodiments is the liquid crystal display device of each of the above-mentioned embodiments in which the liquid crystal element 1 is a TN type liquid crystal element. The liquid crystal molecules of the liquid crystal layer are not limited to one between the front and rear substrates.
STN type in which twist alignment is performed at a twist angle of 80 ° to 270 ° (preferably 200 ° to 250 °), homogeneous alignment type in which liquid crystal molecules are aligned in one direction with their major axes aligned homogeneously, homeotropic alignment type, Lateral electric field type,
A ferroelectric or antiferroelectric type or ECB (birefringence effect) type liquid crystal element may be used.

[0061]

According to the liquid crystal display device of the present invention, an absorption polarizing plate is arranged in front of a liquid crystal element in which a liquid crystal layer is provided between a front substrate which is an observation side of a display and a rear substrate. Reflected polarized light that reflects light of one polarization component and transmits the other polarization component of two linearly polarized light components of the light transmitted through the liquid crystal device and emitted to the rear side to the rear side of the device. An element is arranged, and a light absorption layer is further arranged on the rear side of the reflective polarization element, and light incident from the liquid crystal element side and the reflective polarization element side is provided between the liquid crystal element and the reflective polarization element. Since a surface light source that transmits and emits illumination light toward the reflective polarization element is arranged, both of a reflective display that uses external light and a transmissive display that utilizes illumination light from the surface light source. Can be displayed, and Even when the even transmission display when the reflective display bright, it is possible to obtain a good display with no band colors.

In this liquid crystal display device, the absorption polarization plate and the reflection polarization element have a transmission axis parallel to the vibration plane of the transmission light of the absorption polarization plate and a reflection axis parallel to the vibration plane of the reflection light of the reflection polarization element. It is preferable that the axes are arranged substantially parallel or orthogonal to each other, and by doing so, high contrast display can be obtained in both the reflective display and the transmissive display.

The light absorption layer may be an absorption film that absorbs light in a wavelength band of at least a part of the visible light band, or one of two linearly polarized light components of incident light which are orthogonal to each other. May be an absorption polarizing plate that absorbs the light of the other and transmits the other polarized component. However, when the light absorption layer is an absorption polarizing plate, a light absorption layer made of this absorption polarizing plate is used, and its absorption axis is the reflection of It is preferable that the polarizing element is disposed substantially parallel to the transmission axis of the polarizing element. By doing so, high contrast display can be obtained in both the reflective display and the transmissive display.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a liquid crystal display device showing a first embodiment of the present invention.

FIG. 2 is a sectional view of the liquid crystal display device according to the first embodiment with hatching omitted.

FIG. 3 is a schematic diagram showing a light transmission path of the liquid crystal display device of the first embodiment.

FIG. 4 is a cross-sectional view of a liquid crystal display device showing a second embodiment of the present invention with hatching omitted.

FIG. 5 is an exploded perspective view of a liquid crystal display device showing a third embodiment of the present invention.

[Explanation of symbols]

1 ... Liquid crystal element 2, 3 ... Substrate 5 ... Liquid crystal layer 6 ... Absorption polarizing plate 6a ... transmission axis 7 ... Reflective Polarizing Plate (Reflective Polarizing Element) 7a ... Transmission axis 7b ... Reflective axis 8 ... Light absorbing layer (absorbing film) 9 ... Light absorbing layer (absorption polarizing plate) 9a ... Transmission axis 10 ... Surface light source 11 ... Light guide plate 11a ... Illumination light exit surface 13 ... Light emitting element

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] September 24, 2002 (2002.9.2)
4)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

[0005]

The liquid crystal display device according to the present invention transmits a transmitted light in accordance with an electric field applied between a front substrate which is a viewing side of a display and a rear substrate which faces the front substrate. And a liquid crystal element provided with a liquid crystal layer for controlling the polarization state, and which absorbs light of one polarization component of two linear polarization components of incident light which are arranged in front of the liquid crystal element and are orthogonal to each other, An absorption polarizing plate that transmits the polarized component of
A reflective polarization element that is disposed on the rear side of the liquid crystal element and that reflects one polarized light component of two incident linearly polarized light components and transmits the other polarized light component, and the reflective polarizing element. A light absorption layer disposed further on the back side of
A surface light source that is disposed between the liquid crystal element and the reflective polarization element, transmits the light incident from the liquid crystal element side and the reflective polarization element side, and emits illumination light toward the reflective polarization element. It is characterized by having.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

Further, in the case of transmissive display utilizing the illumination light from the surface light source, the illumination light emitted from the surface light source toward the reflective polarization element enters the reflective polarization element from the front side thereof, of the light, by the reflective polarizing element
Light of the reflected polarized light component, the incident from the rear side to the liquid crystal element, and enters the absorbing polarizer is controlled polarization state by the liquid crystal layer of the liquid crystal element, of the light, the
One straight line with a vibrating surface parallel to the transmission axis of the absorption polarizer
Polarization, and emitted to the front side passes through the absorbing polarizer, the
The other straight line with a vibrating surface parallel to the absorption axis of the absorption polarizer
Polarized light is absorbed by the absorption polarizing plate.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

According to this liquid crystal display device, it is possible to perform both a reflective display utilizing external light and a transmissive display utilizing the illumination light from the surface light source, and also in the reflective display. even when the transmissive display, a single absorption polarizer of the light used for display is disposed in front of <br/> the liquid crystal element 2
Since the light is only transmitted once,
There is little absorption, and therefore the decrease in the intensity of the emitted light relative to the intensity of the incident light is small, and there is almost no banding of the transmitted light due to the wavelength dependence of the light absorption characteristics of the absorption polarizing plate, so that it is transmitted even during reflective display. Also during display, it is possible to obtain a good display that is bright and has no banding.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

As described above, the liquid crystal display device of the present invention is
An absorption polarizing plate is arranged on the front side of a liquid crystal element in which a liquid crystal layer is provided between the front side substrate and the rear side substrate which are the viewing side of the display,
On the rear side of the liquid crystal element, a reflective polarization element that reflects one polarization component of the two linear polarization components of the incident light which are orthogonal to each other and transmits the other polarization component is disposed, and the reflection polarization element is provided. A light absorption layer is further disposed on the rear side, and light incident from the liquid crystal element side and the reflective polarization element side is transmitted between the liquid crystal element and the reflective polarization element, and illumination light is reflected. By arranging a surface light source that emits toward the polarizing element, it is possible to perform both reflective display using external light and transmissive display using illumination light from the surface light source. In both the reflective display and the transmissive display, it is possible to obtain a good display that is bright and has no banding.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

Further, the light absorption layer 8 arranged on the rear side of the reflective polarizing plate 7 is an absorption film for absorbing light in at least a part of the visible light band, for example, all of the visible light band. It consists of an absorption film (black film ) that absorbs light,
It is attached to the rear surface of the reflective polarizing plate 7.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

On the other hand, when an electric field is applied between the electrodes of the liquid crystal element 1 to vertically orient the liquid crystal molecules substantially perpendicular to the surfaces of the substrates 2 and 3 (V> Vth), the absorption polarizing plate is applied. The linearly polarized light S which has passed through 6 and has entered the liquid crystal element 1 passes through the liquid crystal element 1 without changing its polarization state and is emitted to the rear side, as indicated by the solid arrow on the left side of FIG.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction content]

In the case of transmissive display using the illumination light from the surface light source 10, the illumination light (non-polarized light) emitted from the surface light source 10 toward the reflective polarizing plate 7 is the reflected polarized light. The light of the polarization component which is incident on the plate 7 from the front side thereof and which is reflected by the reflective polarizing plate 7 is incident on the liquid crystal element 1 from the rear side and is polarized by the liquid crystal layer 5 of the liquid crystal element 1. The state of the light is controlled to enter the absorption polarizing plate 6, and the light of one polarization component of the light is transmitted through the absorption polarizing plate 6 and emitted to the front side, and the light of the other polarization component is It is absorbed by the absorption polarizing plate 6.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction content]

As described above, in this liquid crystal display device, the absorption polarizing plate 6 is provided in front of the liquid crystal element 1 in which the liquid crystal layer 5 is provided between the front substrate 2 and the rear substrate 3 which are the viewing side of the display. Arranged on the rear side of the liquid crystal element 1 is a reflection polarizing plate 7 that reflects one polarized light component of the two linearly polarized light components of the incident light which are orthogonal to each other and transmits the other polarized light component. A light absorption layer 8 is further arranged behind the reflective polarizing plate 7, and the light is incident between the liquid crystal element 1 and the reflective polarizing plate 7 from the liquid crystal element 1 side and the reflective polarizing plate 7 side. Since the surface light source 10 that transmits the light and emits the illumination light toward the reflective polarizing plate 7 is arranged,
It is possible to perform both reflective display using external light and transmissive display using illumination light from the surface light source 10.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0059

[Correction method] Change

[Correction content]

Further, the reflection polarizing plate 7 of the liquid crystal display device of the third embodiment described above is formed by a laminated film in which λ / 4 phase difference plates are laminated on the entrance surface and the exit surface of the polarization separation film. When replacing with a polarizing element, the absorption polarizing plate 6 and the reflection polarizing element are arranged so that the transmission axis 6a of the absorption polarizing plate 6 and the reflection axis of the reflection polarizing element are substantially parallel or orthogonal to each other as described above. The light absorption layer 9 composed of an absorption polarizing plate is arranged, and the absorption axis thereof is transmitted light of the reflective polarization element (transmits through the polarization separation film and has λ /
It is preferable that the light is emitted as a linearly polarized light by the 4 phase plate and emitted to the rear side of the reflective polarizing element) substantially parallel to the transmission axis parallel to the vibrating surface of the reflective polarizing element. It is possible to obtain a high-contrast display in both reflective display using external light and transmissive display using illumination light from the surface light source 10.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0061

[Correction method] Change

[Correction content]

[0061]

According to the liquid crystal display device of the present invention, an absorption polarizing plate is arranged in front of a liquid crystal element in which a liquid crystal layer is provided between a front substrate which is an observation side of a display and a rear substrate. On the rear side of the element, a reflective polarization element that reflects the light of one polarization component and transmits the other polarization component of the two linear polarization components of the incident light which are orthogonal to each other is arranged, A light absorption layer is further disposed on the side, and light incident from the liquid crystal element side and the reflective polarization element side is transmitted between the liquid crystal element and the reflective polarization element, and illumination light is emitted. Since the surface light source that emits toward the reflective polarization element is arranged, it is possible to perform both reflective display using external light and transmissive display using illumination light from the surface light source. In addition, even in the reflective display, the transmissive display Liver, bright, it is possible to obtain a good display with no band color.

Claims (4)

[Claims] 1. A liquid crystal layer for controlling a polarization state of transmitted light according to an applied electric field is provided between a front substrate which is a viewing side of a display and a rear substrate which faces the front substrate. A liquid crystal element, and an absorption polarizing plate that is disposed on the front side of the liquid crystal element and that absorbs light of one polarization component and transmits the other polarization component of the two linear polarization components of incident light that are orthogonal to each other, Of the two linearly polarized light components, which are arranged on the rear side of the liquid crystal element and transmitted through the liquid crystal element and emitted to the rear side, one of the linearly polarized light components is reflected, and the other polarized light component is reflected. A reflective polarizing element that transmits light, a light absorption layer disposed further behind the reflective polarizing element, disposed between the liquid crystal element and the reflective polarizing element, from the liquid crystal element side and the reflective polarizing element side. The incident light is transmitted and the illumination light is A liquid crystal display device, comprising: a surface light source that emits light toward the reflective polarizing element. 2. An absorption polarizing plate and a reflective polarizing element are substantially provided with a transmission axis parallel to a vibrating surface of transmitted light of the absorbing polarizing plate and a reflective axis parallel to a vibrating surface of reflected light of the reflective polarizing element. The liquid crystal display device according to claim 1, wherein the liquid crystal display devices are arranged in parallel or orthogonal to each other. 3. The liquid crystal display device according to claim 1, wherein the light absorption layer is composed of an absorption film that absorbs light in a wavelength band of at least a part of a visible light band. 4. The light absorption layer absorbs light of one polarization component of two linear polarization components of incident light which are orthogonal to each other,
It is composed of an absorption polarizing plate that transmits the other polarized component, and the absorption axis parallel to the vibration plane of the absorbed light is arranged substantially parallel to the transmission axis parallel to the vibration plane of the transmitted light of the reflective polarization element. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is provided.