JPH11153793A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to control a reflectance and a transmittance by a liquid crystal layer for a light source and a reflection type sheet deflector by holding the liquid crystal layer for light source between substrates, and to make it possible to efficiently use external light and the light source part by transmission. SOLUTION: This liquid crystal display device has; a liquid crystal panel comprising a signal electrode 2 provided on a 1st substrate 1, counter electrodes 7 provided on a 2nd substrate 6, and a liquid crystal layer enclosed between the 1st substrate 1 and the 2nd substrate 6; a light quantity variable type light source part comprising the substrate 1, a liquid crystal layer 30 for the light source, a reflection type sheet polarizer, and emitting part 35, on the side of the substrate 1 facing a user of the liquid display panel; and a light source part for controlling its brightness by varying a reflectance and a transmittance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display mode suitable for low power consumption of a liquid crystal display device, which performs display by using an external light source of the liquid crystal display device in a bright environment in which the liquid crystal display device is used. In a situation where the environment in which the liquid crystal display device is used is dark and the visibility of the display of the liquid crystal display device is reduced, the liquid crystal panel constituting the liquid crystal display device is irradiated with light by using the light source unit of the liquid crystal display device. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a reflection / transmission switching function for performing display using reflection of an external light source and transmission of a light source of the liquid crystal display device.

Further, according to the present invention, the light source section of the liquid crystal display device has a characteristic of reflecting an external light source when the light emitting section constituting the light source section is not turned on. The present invention relates to a liquid crystal panel having a light source unit that changes a reflectance and a transmittance for emitting light to a liquid crystal panel side.

[0003]

2. Description of the Related Art At present, a liquid crystal display device having a reflection / transmission switching function is provided in a direction opposite to an observer of a liquid crystal panel constituting the liquid crystal display device. A permeable film was used. However, in the conventional semi-transmissive film, the ratio between the reflectance and the transmittance can be changed in an initial setting, but cannot be changed in an environment in which a liquid crystal display device is used.

The prior art will be described with reference to the drawings. FIG.
FIG. 1 is a plan view showing a liquid crystal display device with a reflection / transmission switching function according to the related art. FIG. 12 is a cross-sectional view of FIG.
It is sectional drawing in the A line. The prior art will be described below with reference to FIGS.

A first transparent liquid crystal display panel is provided.
A signal electrode 2 made of a transparent conductive film is provided on the substrate 1 of the first embodiment, and a counter electrode 7 is provided on a transparent second substrate 6 arranged with a predetermined gap from the first substrate 1. .

The panel liquid crystal layer 10 provided in the gap between the first substrate 1 and the second substrate 6 includes a sealing material 11 and a sealing material 12.
It is enclosed by. In the prior art, in order to make effective use of the characteristics of the reflector 13 provided on the surface (rear surface) of the first substrate 1 opposite to the second substrate 6 at the same time as emphasizing brightness, the transparent substrate made of a liquid crystal polymer is used. Adopt polymer scattering type liquid crystal mixed with solid matter.

[0007] Reflector 13 provided on the back surface of first substrate 1
The light source unit 37 is disposed on the back surface of the reflection plate 13. The reflection plate 13 shown in the prior art is called a semi-transmission type reflection plate, and when importance is placed on the reflection characteristics, the transmission characteristics are sacrificed. So, for example,
When the silver reflector 13 is used, the saturation, brightness, or the like of silver is sacrificed.

Although not shown in the drawings, the light source 37
Is arranged around the liquid crystal display panel, and the light guide plate is arranged on the back side of the liquid crystal display panel. It is necessary to provide between the substrate 1 and the reflection plate 13, and the characteristics of the reflection plate 13 having a decrease in reflectivity and a scattering property due to the light guide plate will result.

[0009]

As shown in the above prior art, the reflection plate 13 or the semi-transmissive film has both a reflection characteristic and a transmission characteristic. In addition, compared with the case where only the reflection characteristics are used, the reflectivity is poor and a dark display is obtained.

Further, since the ratio of the reflection component to the transmission component cannot be varied in the semi-transmissive film, an optimum state suitable for both reflection and transmission can be selected depending on the use environment of the liquid crystal display device. Can not.

Further, even a small information device using the above-mentioned liquid crystal display device has a reflection / transmission switching function which can make the reflection component and the transmission component variable by a simple mechanism and can optimize in any case. A light source was required.

[0012]

In order to achieve the above object, a liquid crystal display device of the present invention utilizes the following configuration.

According to the liquid crystal display device of the present invention, a signal electrode provided on a first substrate, a counter electrode provided on a second substrate,
A liquid crystal display panel provided between the first substrate and the second substrate; and a liquid crystal display panel for displaying by electro-optical change of the liquid crystal layer for the panel. On the side of the substrate to be formed, a configuration having a variable light amount light source unit including a substrate, a light source liquid crystal layer, and a light emitting unit is adopted.

According to the liquid crystal display device of the present invention, a signal electrode provided on a first substrate, a counter electrode provided on a second substrate,
A liquid crystal display panel provided between the first substrate and the second substrate; and a liquid crystal display panel for displaying by electro-optical change of the liquid crystal layer for the panel. The substrate side has a reflective film that reflects visible light, a substrate, a liquid crystal layer for a light source, and a variable light amount type light source unit including a light emitting unit. When the light source unit is not lit, light from the user side is emitted. A configuration in which light is reflected to the user side by the reflection film of the light source unit is employed.

According to the liquid crystal display device of the present invention, a signal electrode provided on a first substrate, a counter electrode provided on a second substrate,
A liquid crystal display panel provided between the first substrate and the second substrate; and a liquid crystal display panel for displaying by electro-optical change of the liquid crystal layer for the panel. On the side of the substrate, there is a variable light amount type light source unit including a reflective polarizing plate having one polarization axis as a transmission axis and an orthogonal polarization axis as a reflection axis, a substrate, a liquid crystal layer for a light source, and a light emitting unit. Adopt configuration.

According to the liquid crystal display device of the present invention, a signal electrode provided on a first substrate, a counter electrode provided on a second substrate,
A liquid crystal display panel provided between the first substrate and the second substrate; and a liquid crystal display panel for displaying by electro-optical change of the liquid crystal layer for the panel. On the substrate side, a liquid crystal layer for a light source sandwiched between two substrates and a reflective polarizing plate in which one polarization axis provided on the two substrates is a transmission axis and an orthogonal polarization axis is a reflection axis. And the two reflective polarizers are at an angle at which the reflection intensity becomes substantially maximum when no voltage is applied to the liquid crystal layer for the light source.

The variable light amount light source unit employed in the liquid crystal display device of the present invention is characterized in that the light amount can be changed by a voltage applied to a light source liquid crystal layer constituting the light source unit.

The liquid crystal layer for a panel sealed between the first substrate and the second substrate constituting the liquid crystal display panel of the present invention is characterized by comprising a mixed material of a transparent polymer and a liquid crystal.

The liquid crystal layer for the light source constituting the variable light amount light source section of the present invention is characterized in that it is a liquid crystal layer having a memory function.

<Operation> On the surface (rear surface) of the first substrate of the liquid crystal display device opposite to the observer, there is provided a variable light amount type light source unit comprising a substrate, a liquid crystal layer for light source, and a light emitting unit. This light quantity variable type light source section has a mechanism for changing the reflectance and the transmittance by a voltage applied to the light source liquid crystal layer, the functional film, and the light source liquid crystal layer. As described above, in an environment in which the liquid crystal display device is used in a bright environment and the light from the external light source is sufficiently applied to the liquid crystal panel, the reflection characteristic of the light amount variable type light source unit is maximized, and the liquid crystal display device is a reflective type. Function as a liquid crystal display device. As described above, power consumption of the light source unit of the liquid crystal display device can be reduced.

In an environment in which an external light source is weak or almost nonexistent, a light-emitting portion which constitutes a light amount variable type light source portion is turned on.
Furthermore, by controlling the voltage applied to the liquid crystal layer for the light source, the functional film, and the liquid crystal layer for the light source, and maximizing the transmittance, the conventional transflective reflector plate fixes the ratio of the reflectance to the transmittance. , The transmittance can be increased.

The functional film uses a reflection type polarizing plate having one polarization axis as a transmission axis and an orthogonal polarization axis as a reflection axis, and further comprises a light source liquid crystal layer constituting a variable light quantity type light source section. By adopting a reflective deflecting plate both above and below, the reflection characteristics can be improved as compared with a case where one is a reflective deflecting plate and the other is an absorbing deflecting plate. This absorption type polarizing plate is a polarizing plate having one polarization axis as a transmission axis and the other polarization axis as an absorption axis.

The liquid crystal layer for the light source employed in the variable light source type light source section is arranged so that the reflection characteristic is maximized by the arrangement of the liquid crystal layer for the light source and the reflective deflecting plate. The reflection characteristics can be improved. In addition, by providing an arrangement having reflection characteristics when no voltage is applied, the voltage for driving the light source liquid crystal layer can be reduced, and at the same time, the reflectance can be improved.

Further, by adopting a mixed liquid crystal layer of a liquid crystal and a transparent polymer as the liquid crystal layer for the panel constituting the liquid crystal display device, the liquid crystal layer for the panel has a scattering property and a transmissivity.
Therefore, the display quality is improved by adopting the reflection characteristics of the variable light amount light source unit and, in particular, the scattering characteristics of the panel liquid crystal layer, as compared with the case where the panel liquid crystal layer of another display mode is employed. Can be.

Further, a liquid crystal layer having a memory property is adopted as a liquid crystal layer for a light source constituting a variable light quantity type light source section.
In addition, the driving means employs a direct current drive employing a charge storage capacitor, and employs a means for changing the polarity of the capacitor each time the transmission and reflection of the variable light amount type light source unit are controlled.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal display device having a variable light amount type light source unit according to the best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of the liquid crystal display device according to the first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line BB shown in FIG. FIG. 3 is a schematic diagram for explaining the arrangement of the polarizing plates of the light amount variable type light source unit, and FIG. 4 is a graph showing the arrangement angle and the reflectance of the polarizing plates shown in FIG. The first embodiment will be described below with reference to FIG. 1, FIG. 2, FIG. 3, and FIG.

<First Embodiment> A liquid crystal panel, which is a part of the structure of a liquid crystal display device, comprises a transparent first substrate 1 and a first
And a transparent second substrate 6 opposed to the substrate 1 with a predetermined gap. On the first substrate 1, there are provided M signal electrodes 2 made of an indium tin oxide (ITO) film as a transparent conductive film. On a second substrate 6 facing the first substrate 1 with a predetermined gap, there are N data electrodes 7. The intersection between the signal electrode 2 and the data electrode 7 becomes the pixel section 13.

The pixel section 13 is composed of an M * N matrix. Further, between the first substrate 1 and the second substrate 6, a polymer scattering type liquid crystal layer 10 which becomes a transparent solid polymer after a monomer is mixed into the liquid crystal and irradiated with ultraviolet rays is adopted. The panel liquid crystal layer 10 is enclosed by the first substrate 1, the second substrate 6, a seal portion 11, and a sealing material 12.

The second substrate 6 is arranged on the user (observer) side of the liquid crystal display device. On the surface (back surface) of the first substrate 1 opposite to the observer, a variable light amount type light source unit, which is a feature of the present invention, is disposed. When the display is performed using the polymer scattering type liquid crystal layer 10, the display is performed using the scattering and the transmissivity. Therefore, when the external environment is bright, the display is arranged on the back side of the first substrate 1. Display is performed using the ratio of the reflected light from the reflective film to be scattered and the scattered light of the panel liquid crystal layer 10. Alternatively, a light absorbing film is disposed on the back side of the first substrate 1, and display is performed based on a difference between the scattering property and the absorption property. In the present invention, a variable light amount type light source unit having reflection characteristics is disposed on the back surface of the first substrate 1.

That is, on the back surface side of the first substrate 1, there are provided a transparent third substrate 21 and a fourth substrate 24 arranged with a predetermined gap from the third substrate 21. Third substrate 21
The lower electrode 22 made of a transparent conductive film and having no pattern is formed thereon. Similarly, on the fourth substrate 24,
Unpatterned upper electrode 2 made of a transparent conductive film
3

A gap between the third substrate 21 and the fourth substrate 24 has a twisted nematic liquid crystal layer (TN). The liquid crystal layer 30 for a light source is enclosed by a third substrate 21, a fourth substrate 24, a sealing portion (not shown), and a sealing material (not shown). An alignment film (not shown) is provided on the third substrate 21 and the fourth substrate 24 in order to arrange the liquid crystals regularly. Further, the alignment film is subjected to a rubbing treatment in order to arrange the light source liquid crystal layer 30 regularly. Further, a chiral material was added to the light source liquid crystal layer 30 in order to twist the liquid crystal.

Further, on the third substrate 21 and the fourth substrate 26
On the upper side, reflection-type polarizing plates 25 and 26 having one polarization axis as the reflection axis and the orthogonal polarization axis as the transmission axis are arranged. The reflection type polarizing plate provided on the third substrate 21 is the third polarizing plate 2
5 and the reflection type deflection plate provided on the fourth substrate 26 is the fourth
Of the polarizing plate 26. The third polarizing plate 24 and the fourth polarizing plate 25 are arranged so that the reflection axes are parallel to each other, and the light source liquid crystal layer 30 has an optical rotation of 90 °. Therefore, the arrangement is such that the reflection characteristics are maximized when no voltage is applied to the light source liquid crystal layer 30.

Further, on the back side of the third substrate 21, a cold cathode fluorescent tube is used as the light emitting portion 35, and further, a diffusion layer 36 provided for diffusing and uniformizing the light of the light emitting portion 35 is provided.
In the first embodiment, the third polarizing plate 25, the third substrate 21, the lower electrode 22, the liquid crystal layer for light source 30, the upper electrode 23, the fourth substrate 24, and the fourth Are arranged to constitute a variable light quantity type light source section 37.

By providing the variable light amount light source section 37 described above, when the use environment of the liquid crystal display device is bright,
The light amount variable light source section 37 disposed on the back side of the liquid crystal panel composed of the first substrate 1 and the second substrate 6 is larger than the two reflective deflection plates 25 and 26 and the light source liquid crystal layer 30. Has reflective properties. On the other hand, when the external environment is dark, a voltage is applied to the liquid crystal layer 30 for the light source to cancel the optical rotation of the liquid crystal layer 30 for the light source. As described above, the light of the light emitting section 35 passes through the third polarizing plate 25, travels almost without being affected by the light source liquid crystal layer 30, and passes through the fourth polarizing plate 26,
It reaches the liquid crystal display panel, and goes to the observer or performs display under the action of transmission or scattering of the polymer scattering type liquid crystal.

The positional relationship among the third polarizing plate 25, the fourth polarizing plate 26, and the light source liquid crystal layer 30 used in the variable light amount light source unit 37 used in the first embodiment will be described with reference to the drawings. explain. As shown in FIG.
Is traveling toward the observer side from the light source unit 37 of a variable light amount type. Further, from the light emitting unit side, a third polarizing plate 25, a third substrate 21, a lower electrode (not shown), an alignment film (not shown),
A liquid crystal layer 30 for a light source, an alignment film (not shown), an upper electrode (not shown), a fourth substrate 24, and a fourth polarizing plate 26 are provided in this order.

First, the reflection axis of the third polarizing plate 25 is set in the direction of arrow 18. The alignment direction of the alignment film on the third substrate 21 is the arrow direction 16 that matches the direction 18 of the reflection axis of the third polarizing plate 25. Since the light source liquid crystal layer 30 employs a 90 ° twisted nematic liquid crystal layer, the alignment direction on the fourth substrate 24 is the arrow direction 17 orthogonal to the alignment direction on the third substrate 21.

Here, the direction of the reflection axis of the fourth polarizing plate 26 is set to the arrow direction 19 which matches the direction of the orientation on the fourth substrate 24.
Is 0 °, an angle 20 that rotates from the arrow direction 19
(Θ). FIG. 4 shows the angle at which the fourth polarizing plate 26 is parallel to the fourth substrate 24 and rotates around the light beam 15 and the reflectance between the third and fourth polarizing plates 25 and 26 and the light source liquid crystal layer 30. 6 is a graph showing the relationship of. The horizontal axis indicates the angle θ, and the vertical axis indicates the reflectance. As shown in FIG.
When no voltage is applied, the reflectance increases as the angle θ increases to 90 °. 90 ° to 180
In °, the reflectance sharply decreases with an increase in the angle θ.

According to the experiment, the angle θ at which the fourth polarizing plate 26 is arranged shows the maximum reflectance (Rmax) when it is 90 °, and when it is in the range of 85 ° to 95 °, the reflection of 80% or more of Rmax is obtained. Rate can be achieved. Therefore, in consideration of the dispersion of the polarizing plate and the positional accuracy between the light source unit 37 of the variable light amount type and the liquid crystal display panel, the angle at which the fourth polarizing plate 26 is arranged is 8
5 ° to 95 ° is considered to be a reasonable range. The above-described liquid crystal layer 30 for a light source is an example relating to a 90 ° twisted nematic liquid crystal layer. However, even in a super twisted nematic liquid crystal layer of 90 ° or more, it is necessary to increase coloring and reflection intensity by a phase difference of the super twisted nematic liquid crystal layer. A retardation film is arranged, the retardation film is inserted into the configuration shown in FIG. 3, and the angle between the polarizing plate and the retardation film can be varied to obtain an optimum value.

<Second Embodiment> A liquid crystal display device having a variable light quantity type light source unit according to a second embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is another sectional view showing a portion equivalent to the sectional view taken along line BB of the liquid crystal display device according to the first embodiment of the present invention. Hereinafter, a second embodiment will be described with reference to FIG. The numbers used in the drawings are the same as those in the first embodiment, and the same numbers indicate the same contents.

The liquid crystal panel, which is a part of the configuration of the liquid crystal display device, has a transparent first substrate 1 and a transparent second substrate 6 which faces the first substrate 1 with a predetermined gap. . On the first substrate 1, there are provided M signal electrodes 2 made of an indium tin oxide (ITO) film as a transparent conductive film. On a second substrate 6 facing the first substrate 1 with a predetermined gap, there are N data electrodes 7. The intersection between the signal electrode 2 and the data electrode 7 becomes the pixel section 13.

The pixel section 13 is composed of an M * N matrix. A 90 ° twisted nematic liquid crystal layer (TN) 10 is provided between the first substrate 1 and the second substrate 6.
Having. The liquid crystal layer 10 for a panel includes the first substrate 1 and the second
Substrate 6, sealing part (not shown), and sealing material (not shown)
And enclosed by. Also, the first substrate 1 and the second
An alignment film (not shown) is provided on the substrate 6 to regularly arrange the liquid crystals. Further, the alignment film is subjected to a rubbing treatment in order to arrange the panel liquid crystal layer 10 regularly. Further, a chiral material was added to the panel liquid crystal layer 10 in order to twist the liquid crystal.

The twisted nematic liquid crystal layer is visualized by using a polarizing plate in order to vary the optical rotation of the light according to the applied voltage. Therefore, a first polarizing plate 8 is provided on the back side of the first substrate 1, and a second polarizing plate 9 is provided on the front side of the second substrate. The transmission polarization axes of the first polarizing plate 8 and the second polarizing plate 9 are orthogonal to each other. Therefore, the 90 ° twisted nematic liquid crystal layer 10
Since the 0 ° polarization axis rotates, it becomes transparent when no voltage is applied to the liquid crystal layer 10 for panel. On the back side of the liquid crystal display panel having the above configuration, the light amount variable light source section 37 of the present invention is provided.
Is provided. In the second embodiment, a polarizing plate used for the variable light amount light source unit 37 is also used as a polarizing plate used for display.

On the back surface side of the first substrate 1, there is provided a transparent third substrate 21 and a fourth substrate 24 arranged with a predetermined gap from the third substrate 21. On the third substrate 21,
Unpatterned lower electrode 2 made of a transparent conductive film
2 Similarly, on the fourth substrate 24, an unpatterned upper electrode 23 made of a transparent conductive film is provided. An insulating film (not shown) formed by a printing method is provided on the upper electrode 23 in order to prevent an electrical short circuit between the lower electrode 22 and the upper electrode 23. Lower electrode 22 and upper electrode 23
The third substrate 21 and the fourth substrate 24 have a small thickness and have a bonding step to a liquid crystal display panel, so that an electrical short circuit is prevented very much by the insulating film. It became possible to do.

The gap between the third substrate 21 and the fourth substrate 24 has a twisted nematic liquid crystal layer (TN). The liquid crystal layer 30 for a light source is enclosed by a third substrate 21, a fourth substrate 24, a sealing portion (not shown), and a sealing material (not shown). An alignment film (not shown) is provided on the third substrate 21 and the fourth substrate 24 in order to arrange the liquid crystals regularly. Further, the alignment film is subjected to a rubbing treatment in order to arrange the light source liquid crystal layer 30 regularly. Further, a chiral material was added to the light source liquid crystal layer 30 in order to twist the liquid crystal.

Further, only on the third substrate 21, a reflection type polarizing plate 25 whose one polarization axis is a reflection axis and whose orthogonal polarization axis is a transmission axis is arranged. The fourth polarizing plate provided on the fourth substrate 24 is also used as the first polarizing plate 8. First
The polarizing plate 8 also employs a reflective polarizing plate. The reflection type polarizing plate provided on the third substrate 21 is referred to as a third polarizing plate. The third polarizing plate 24 and the first polarizing plate 8 are arranged so that the reflection axes are parallel to each other, and the light source liquid crystal layer 30 has an optical rotation of 90 °. Therefore, the arrangement is such that the reflection characteristics are maximized when no voltage is applied to the light source liquid crystal layer 30.

Further, on the back surface side of the third substrate 21, a cold cathode fluorescent tube is used as the light emitting section 35, and a diffusion layer 36 provided for diffusing and uniformizing the light of the light emitting section 35 is provided.
In the second embodiment, the third polarizing plate 25, the third substrate 21, the lower electrode 22, the light source liquid crystal layer 30, the upper electrode 23, the fourth substrate 24, and the first The polarizing plate 8 is arranged to constitute a light amount variable light source unit 37.

As is clear from the above description, by using both the first polarizing plate 8 and the fourth polarizing plate, the distance between the display portion of the liquid crystal display panel and the reflecting plate can be reduced. In addition, the overall thickness can be reduced. Further, by providing the above-mentioned variable light amount type light source unit 37, when the use environment of the liquid crystal display device is bright, the light source unit 37 is disposed on the back side of the liquid crystal panel composed of the first substrate 1 and the second substrate 6. The variable light amount light source unit 37 includes two reflection type deflection plates 8,
25 and the light source liquid crystal layer 30 have greater reflection characteristics. On the other hand, when the external environment is dark, a voltage is applied to the liquid crystal layer 30 for the light source to cancel the optical rotation of the liquid crystal layer 30 for the light source. As described above, the light of the light emitting unit 35 is transmitted to the third polarizing plate 2.
5 and travels without being substantially affected by the light source liquid crystal layer 30, pass through the first polarizing plate 8, reach the liquid crystal display panel, and form the liquid crystal display panel with the first polarizing plate 8 and the panel liquid crystal. The layer 10 and the second polarizing plate 9 control transmission and blocking of predetermined light to enable display.

Further, a process having a scattering property is performed on the second polarizing plate 9 to perform a process for improving the reflection characteristics of the light source unit 37 of the variable light amount type, thereby eliminating the dependence of the position between the light source and the observer. Employing the method further improves the features of the second embodiment of the present invention.

<Third Embodiment> A liquid crystal display device having a variable light quantity type light source unit according to a third embodiment of the present invention will be described below with reference to the drawings. FIG. 6 is another sectional view showing a portion equivalent to the sectional view taken along line BB of the liquid crystal display device according to the first embodiment of the present invention. Hereinafter, a third embodiment will be described with reference to FIG. The numbers used in the drawings are the same as those in the first embodiment, and the same numbers indicate the same contents.

The liquid crystal panel, which is a part of the configuration of the liquid crystal display device, has a transparent first substrate 1 and a transparent second substrate 6 opposed to the first substrate 1 with a predetermined gap. . On the first substrate 1, there are provided M signal electrodes 2 made of an indium tin oxide (ITO) film as a transparent conductive film. On a second substrate 6 facing the first substrate 1 with a predetermined gap, there are N data electrodes 7. The intersection between the signal electrode 2 and the data electrode 7 becomes the pixel section 13.

The pixel section 13 is composed of an M * N matrix. Further, between the first substrate 1 and the second substrate 6,
A polymer scattering type liquid crystal layer 10 which becomes a polymer of a transparent solid after the monomer is mixed into the liquid crystal and irradiated with ultraviolet rays is employed. The panel liquid crystal layer 10 includes a first substrate 1 and a second substrate 6.
, A sealing portion 11 and a sealing material 12.

Further, on the back surface side of the liquid crystal display panel having the above-described structure, a variable light amount type light source unit 37 of the present invention is provided. A feature of the third embodiment of the present invention is that the third polarizing plate 25 and the lower electrode 22 are directly provided on the diffusion layer 36 provided on the light emitting section 35, and the third substrate is not provided. Thereby, the thickness of the light amount variable type light source unit 37 can be reduced.

On the back side of the first substrate 1, a light emitting section 35, a third polarizing plate 25 composed of a reflective polarizing plate provided on the light emitting section 35, and a lower electrode 22 on which no pattern is formed are provided.
Further, a fourth substrate 24 provided with a predetermined gap provided by the lower electrode 22 and the spacer 31 and an unpatterned upper electrode 23 made of a transparent conductive film provided on the fourth substrate 24 are provided. On the upper electrode 23, the lower electrode 2
An insulating film (not shown) formed by a printing method is provided to prevent an electrical short circuit between the second electrode 2 and the upper electrode 23.

Further, between the fourth substrate 24 and the first substrate 1, a fourth polarizing plate 26 composed of a reflection type polarizing plate is disposed. In the gap between the lower electrode 22 and the upper electrode 23, a twisted nematic liquid crystal layer (TN) is provided as the light source liquid crystal layer 30. The light source liquid crystal layer 30 is formed on the third substrate 2.
The first and fourth substrates 24 are sealed by a sealing portion (not shown) and a sealing material (not shown). An alignment film (not shown) is provided on the third substrate 21 and the fourth substrate 24 in order to arrange the liquid crystals regularly. Further, the alignment film is subjected to rubbing treatment in order to regularly arrange the light source liquid crystal layers 30. Further, a chiral material was added to the light source liquid crystal layer 30 in order to twist the liquid crystal.

Further, the third polarizing plate 25 and the fourth polarizing plate 26 are arranged so that their reflection axes are parallel to each other, and the light source liquid crystal layer 30 has an optical rotation of 90 °.
Therefore, the arrangement is such that the reflection characteristics are maximized when no voltage is applied to the light source liquid crystal layer 30.

Further, on the back side of the third polarizing plate 25,
The light source unit 37 includes a cold cathode fluorescent tube as the light emitting unit 35 and a diffusion layer 36 provided to diffuse and uniform the light of the light emitting unit 35. In the first embodiment,
On the light emitting section 35, a third polarizing plate 25, a lower electrode 22, a liquid crystal layer 30 for a light source, an upper electrode 23, a fourth substrate 24 and a fourth polarizing plate 26 are arranged, and a light amount variable type light source section is provided. 37.

By providing the variable light amount light source section 37, when the use environment of the liquid crystal display device is bright,
The light amount variable light source section 37 disposed on the back side of the liquid crystal panel composed of the first substrate 1 and the second substrate 6 is larger than the two reflective deflection plates 25 and 26 and the light source liquid crystal layer 30. Has reflective properties. On the other hand, when the external environment is dark, a voltage is applied to the liquid crystal layer 30 for the light source to cancel the optical rotation of the liquid crystal layer 30 for the light source. As described above, the light of the light emitting section 35 passes through the third polarizing plate 25, travels almost without being affected by the light source liquid crystal layer 30, and passes through the fourth polarizing plate 26,
It reaches the liquid crystal display panel, and goes to the observer or performs display under the action of transmission or scattering of the polymer scattering type liquid crystal.

As is clear from the above description, the adoption of the polymer scattering type liquid crystal layer 10 containing a transparent solid material in the liquid crystal allows the reflection characteristic of the light amount variable type light source section 37 and the transmission of the panel liquid crystal layer 10. Brightness can be displayed by utilizing the difference in light scattering properties. Further, when the light emitting unit 35 is turned on, the reflection characteristic is reduced by the light source liquid crystal layer 30 and the polarizing plates 25 and 26, and the light is emitted from the light emitting unit 35 by the transmission characteristic. To the observer. Therefore, the polymer scattering type liquid crystal layer 10 that does not use a polarizing plate in the liquid crystal display panel has no influence on the reflectors 25 and 26 that constitute the light source unit 37 of the variable light amount type. It is possible to optimize the light source unit 37 of the mold.

Further, by using the third substrate and the third polarizing plate 25 together, the thickness can be reduced, and the reflection at the interface between the constituent members can be reduced, so that the brightness can be improved.

<Fourth Embodiment> A liquid crystal display device having a variable light quantity type light source unit according to a fourth embodiment for carrying out the present invention will be described below with reference to the drawings. FIG. 7 is another sectional view showing a portion equivalent to the sectional view taken along line BB of the liquid crystal display device according to the first embodiment of the present invention. Hereinafter, a fourth embodiment will be described with reference to FIG. The numbers used in the drawings are the same as those in the first embodiment, and the same numbers indicate the same contents.

A liquid crystal panel, which is a part of the configuration of the liquid crystal display device, has a transparent first substrate 1 and a transparent second substrate 6 which faces the first substrate 1 with a predetermined gap. . On the first substrate 1, there are provided M signal electrodes 2 made of an indium tin oxide (ITO) film as a transparent conductive film. On a second substrate 6 facing the first substrate 1 with a predetermined gap, there are N data electrodes 7. The intersection between the signal electrode 2 and the data electrode 7 becomes the pixel section 13.

The pixel section 13 is composed of an M * N matrix. Further, between the first substrate 1 and the second substrate 6, a guest-host type panel liquid crystal layer 10 including a dichroic dye in the liquid crystal is employed. In the guest-host type, when a voltage is applied to the liquid crystal layer 10 for a panel, the positions of the molecules of the dichroic dye are controlled in accordance with the movement of the molecules of the liquid crystal, and the amount of light absorption changes. The liquid crystal layer 10 for a panel
The first substrate 1, the second substrate 6, a sealing portion (not shown), and a sealing material (not shown) are enclosed. Further, an alignment film (not shown) is provided on the first substrate 1 and the second substrate 6 in order to regularly arrange liquid crystals. Further, the alignment film is subjected to a rubbing treatment in order to arrange the panel liquid crystal layer 10 regularly. The rubbing direction is 200 ° to 24 ° for the first substrate 1 and the second substrate 6.
It has an angle of 0 °. Further, a chiral material was added to the panel liquid crystal layer 10 to twist the liquid crystal.

Further, on the back surface side of the liquid crystal display panel having the above-described structure, a variable light amount light source unit 37 of the present invention is provided. A feature of the fourth embodiment of the present invention is that a protection layer (not shown) for preventing the transmission of moisture and the transmission of impurity ions is provided on the fourth polarizing plate 24 provided on the back surface of the first substrate 1. After that, the upper electrode 23 is directly provided, the third polarizing plate 25 and the lower electrode 22 are directly provided on the diffusion layer 36 provided on the light emitting section 35, and the third substrate and the fourth substrate are not provided. It is. Thus, the thickness of the variable light amount light source unit 37 can be greatly reduced. Further, the light emitting section 35 is provided around the pixel section of the liquid crystal display panel, and the uniformity of light and the reduction in thickness can be achieved at the same time by the light guide plate and the diffusion layer provided in the variable light amount light source section 37.

On the back side of the first substrate 1, a light emitting section 35, a third polarizing plate 25 composed of a reflective polarizing plate provided on the light emitting section 35, and a lower electrode 22 on which no pattern is formed are provided.
Further, an upper electrode 23 made of a transparent conductive film and having no pattern formed thereon is provided on the fourth polarizing plate 26 arranged with a predetermined gap provided by the lower electrode 22 and the spacer 31. An insulating film (not shown) formed by a printing method is provided on the upper electrode 23 in order to prevent an electrical short circuit between the lower electrode 22 and the upper electrode 23.

The gap between the lower electrode 22 and the upper electrode 23 has a ferroelectric liquid crystal as the light source liquid crystal layer 30. The ferroelectric liquid crystal is sealed by a third substrate 21, a fourth substrate 24, a sealing portion (not shown), and a sealing material (not shown). Further, an alignment film (not shown) is provided on the lower electrode 22 and the upper electrode 23 in order to regularly arrange liquid crystals. Further, the alignment film is subjected to a rubbing treatment in order to regularly arrange ferroelectric liquid crystals. When a voltage is applied to the above ferroelectric liquid crystal and the third or fourth polarizer 25 or 26 switches to transmissive or reflective, the state is maintained until the next voltage is applied. It has the memory property to do. Therefore, when a variable light quantity light source unit is configured, the liquid crystal is a very effective liquid crystal in order to reduce the power consumed for the operation of the light source liquid crystal layer 30.

The driving of the light source liquid crystal layer 30 is intermittent driving, and the problem of deterioration is wider than that of the panel liquid crystal layer 10 used for the liquid crystal display panel for display. Since the lower electrode 22 and the lower electrode 22 are not patterned, a method of driving with a DC voltage was employed. For driving, a method was adopted in which the battery voltage was boosted, charges were stored in a storage capacitor, and a large DC voltage was applied to the ferroelectric liquid crystal. For this reason, the drive circuit can be extremely simplified.

Further, the ferroelectric liquid crystal and the polarizing plates 25 and 26
The cone angle of the ferroelectric liquid crystal, which determines the contrast due to the above, is determined by setting the angle between the third polarizing plate 25 made of a reflective polarizing plate and the fourth polarizing plate 26 made of a reflective polarizing plate to the angle at which the reflectance is maximized. I made it.

In the fourth embodiment, as apparent from the above description, the third substrate and the fourth substrate constituting the light amount variable type light source section 37 are replaced by the third polarizing plate 25 and the third substrate. 4
, The thickness of the variable light amount light source unit 37 can be greatly reduced. Further, by employing a ferroelectric liquid crystal for the light source liquid crystal layer 30, the amount of electricity for driving the light source liquid crystal layer 30 can be greatly reduced. Further, by driving the liquid crystal layer 30 for the light source with a DC voltage, the circuit can be significantly reduced.

Further, by employing the guest-host type liquid crystal layer 10 containing a dichroic dye in the liquid crystal, the difference between the reflection characteristics of the variable light amount light source unit 37 and the transmission and absorption characteristics of the guest-host type liquid crystal layer 10 is utilized. Thus, a bright display becomes possible. Further, when the light emitting unit 35 is turned on, the reflection characteristic is reduced by the light source liquid crystal layer 30 and the polarizing plates 25 and 26, and the light is emitted from the light emitting unit 35 by the transmission characteristic. The light passes through the transmitting part and reaches the observer. Therefore, the guest-host type liquid crystal layer 10 using a polarizing plate for the liquid crystal display panel does not affect the reflectors 25 and 26 constituting the light source unit 37 of the variable light amount type. The light source unit 37 can be optimized.

An embodiment in which the liquid crystal display device having the above configuration is used for a small information device will be described with reference to FIGS. FIG. 8 is a plan view showing a small information device, and FIG.
FIG. 9 is a sectional view taken along line CC of FIG. 8. Figure 9 below
The configuration of the arm information device, which is one of the small information devices, will be described with reference to FIG. 10 and FIG.

The watch case 41 constituting the arm information device has a windshield 42 and a back cover 43. Parting plate 47 that shields sealing material 11 and the like from windshield 42 side
, The character 48 provided on the parting plate 47, the second substrate 6, the counter electrode 7, the polymer scattering type liquid crystal layer 10, the signal electrode 2, the first
Liquid crystal display panel comprising a substrate 1, a fourth polarizer 26 comprising a reflective deflecting plate, an upper electrode 23, an alignment film (not shown), a light source liquid crystal layer 30 comprising a ferroelectric liquid crystal, and a lower electrode 22 And a third polarizing plate 25 composed of a reflective deflecting plate, and an electroluminescent (EL) element that is a plane light emitting section 35. Further, the liquid crystal display panel is connected to the circuit board 44 by a zebra rubber 46. Further, a variable light quantity light source section 37 is also connected to the circuit board 44. Further, the circuit board 34 has a secondary battery 45.

Since the display of the arm information device has the liquid crystal display device shown in the fourth embodiment, a liquid crystal display panel having a matrix type pixel portion and a guest host type panel liquid crystal layer 10 and a liquid crystal for a light source are provided. The layer 30 includes a variable light quantity type light source section 37 having a ferroelectric liquid crystal having a memory property.

The display of the arm information device includes a year display 51,
A date display section 59 including a month display 52, a day display 53, and a day display 58, an am and pm display 54, an hour display 55,
And a time display section 57 including a minute display 56. In particular, for the arm information device, in order to reduce power consumption, the date display unit 59 uses a matrix-type pixel unit with a low density, and the time display unit 57 uses a segment-type pixel unit. Adopted. Each display unit can be independently turned on and off according to a request from the observer or a timer.

Further, the arm information device has an adjustment button 60 for adjusting the time, etc., for adjusting the time, adjusting the day of the week, and switching the mode to the chronograph mode. In addition, in order to control ON / OFF of the variable light amount type light source unit 37, a light source unit control button 61 and an optical sensor 62 composed of a silicon diode for automatically turning on according to the brightness of the external environment are provided.

The operation control of the arm information device of this embodiment will be described with reference to a system block diagram for controlling the arm information device. FIG. 11 is a system block diagram for explaining the control of the liquid crystal display panel of the present wristwatch device and the variable light amount type light source unit provided on the back side of the liquid crystal display panel.

A basic clock transmission circuit 71 for displaying the time of the wristwatch device supplies a reference signal to a time signal generation circuit 72, and further, a segment control signal generation circuit for driving a liquid crystal display panel of the time display section 57. 79 to the signal. The segment control signal generation circuit 79 is provided between the signal electrode 2 on the first substrate 1 of the liquid crystal display panel and the second substrate 6.
A predetermined display is performed by applying a signal to the upper counter electrode 7.

The segment control signal generating circuit 79
Applies a signal of a horizontal synchronization circuit 75 and a signal of a vertical synchronization circuit 74 to drive a matrix type liquid crystal display panel of the date display section 59, and further, the horizontal synchronization circuit 75 is connected via a scan electrode driving circuit 76. A predetermined signal is applied to the counter electrode on the second substrate 6. The vertical synchronization circuit 74 applies a predetermined voltage to the signal electrodes on the first substrate 1 via the gradation signal generation circuit 78 and the data electrode drive circuit 80.

The variable light amount light source unit is provided on the third substrate 2.
A predetermined voltage is applied to the light source liquid crystal layer composed of the first and fourth substrates 24, the light source liquid crystal layer (not shown), and the polarizing plate (not shown) to control the transmission and reflection characteristics, and the light emitting unit 35 In order to adjust the amount of light reaching the liquid crystal display panel from the light source, the voltage applied to the liquid crystal layer for the light source is controlled by the light amount variable type light source unit control circuit based on the information of the light sensor 62 for measuring the brightness of the external environment and the light source unit control button 61 A predetermined voltage is applied to a lower electrode (not shown) provided on the third substrate 21 and an upper electrode (not shown) provided on the fourth substrate via a light amount variable type liquid crystal display panel control circuit 84 to be controlled. It controls the transmittance of the light amount variable type light source unit.

The light emitting section 35 and the variable light quantity type liquid crystal display panel control circuit 84 are also electrically connected, and follow the switching of the reflectance and the transmittance of the variable light quantity type light source section. Do off.

As described above, by adopting a variable light amount light source unit in a small information device, it is possible to control the reflectance and the transmittance, and to apply the light to the light emitting unit 35 and the liquid crystal layer for the light source. By interlocking with the voltage, the light source unit can be used efficiently.

Also, by employing an optical sensor,
By comparing the brightness of the environment in which small information devices are used with the brightness of the light source and the reflectance, control the lighting and non-lighting of the light source, or turn on the light source and control the transmittance of the variable light quantity LCD panel. It becomes possible. Therefore, as compared with the related art, the brightness adjustment of the light source unit suitable for the environment in which the small-sized information device is used can be used in a situation where the light emission efficiency of the light source unit is optimal.

In the embodiment of the present invention, an example is shown in which a color film and a color filter are not provided between the first substrate and the fourth polarizing plate or between the third polarizing plate and the scattering layer. The effects of the present invention can be achieved by using a color film and a color filter.

In the embodiment of the present invention, there has been described an example in which a reflection-type deflecting plate is used which transmits light in a wavelength range of visible light substantially averagely through one optical axis and reflects the light in an orthogonal optical axis. However, the effects of the present invention can also be achieved by using a reflective deflecting plate that transmits and reflects light in a specific wavelength range.

Further, in the embodiment of the present invention, when external light is weak, when the light emitting portion of the variable light quantity light source section is turned on, voltage control of the liquid crystal layer constituting the variable light quantity light source section is performed. Although the description has been given with respect to increasing the transmittance, even when the external light is very strong and the reflection intensity of the light amount variable type light source unit is too strong, a voltage is applied to the light source liquid crystal layer to reduce the reflectance. By lowering, visibility can be improved.

[0085]

According to the present invention, the first substrate of the liquid crystal display device has a variable light amount light source section comprising a substrate, a light source liquid crystal layer, and a light emitting section on the side opposite to the observer (back side). This light quantity variable type light source section has a mechanism for changing the reflectance and the transmittance by a voltage applied to the light source liquid crystal layer, the functional film, and the light source liquid crystal layer. As described above, in an environment in which the liquid crystal display device is used in a bright environment, and in which the liquid crystal panel is sufficiently irradiated with light from an external light source, the reflection characteristic of the light amount variable type light source unit is maximized. Functions as a liquid crystal display device. As described above, power consumption of the light source unit of the liquid crystal display device can be reduced.

In an environment where the external light source is weak or almost non-existent, the light-emitting portion constituting the variable light amount type light source portion is turned on.
Furthermore, by controlling the voltage applied to the liquid crystal layer for the light source, the functional film, and the liquid crystal layer for the light source, and maximizing the transmittance, the conventional transflective reflector plate fixes the ratio of the reflectance to the transmittance. , The transmittance can be increased.

The functional film uses a reflection type polarizing plate having one polarization axis as a transmission axis and an orthogonal polarization axis as a reflection axis, and further comprises a light source liquid crystal layer constituting a variable light quantity type light source section. By adopting a reflective deflecting plate both above and below, the reflection characteristics can be improved as compared with a case where one is a reflective deflecting plate and the other is an absorbing deflecting plate. This absorption type polarizing plate is a polarizing plate having one polarization axis as a transmission axis and the other polarization axis as an absorption axis.

Further, the liquid crystal layer for the light source employed in the light source section of the variable light amount type is arranged so as to maximize the reflection characteristic by the arrangement of the liquid crystal layer for the light source and the reflective deflecting plate. The reflection characteristics can be improved.
In addition, by providing an arrangement having reflection characteristics when no voltage is applied, the voltage for driving the light source liquid crystal layer can be reduced, and at the same time, the reflectance can be improved.

Further, by adopting a mixed liquid crystal layer of liquid crystal and a transparent polymer as the liquid crystal layer for the panel constituting the liquid crystal display device, the liquid crystal layer for the panel has a scattering property and a transmissivity.
Therefore, the display quality is improved by adopting the reflection characteristics of the variable light amount light source unit and, in particular, the scattering characteristics of the panel liquid crystal layer, as compared with the case where the panel liquid crystal layer of another display mode is employed. Can be.

In addition, a liquid crystal layer having a memory property is adopted as a liquid crystal layer for a light source constituting a variable light quantity type light source section.
In addition, the driving means employs a direct current drive employing a charge storage capacitor, and employs a means for changing the polarity of the capacitor each time the transmission and reflection of the variable light amount type light source unit are controlled.

Further, since the reflectance and transmittance of the variable light quantity type liquid crystal display panel comprising the liquid crystal layer for light source, the polarizing plate and the electrodes can be controlled by the voltage applied to the liquid crystal layer for light source, the brightness of the light source section can be controlled. And the reflection characteristics of the light source unit can be changed, and brightness adjustment suitable for the use environment can be performed as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating a positional relationship between a polarizing plate and a light source liquid crystal layer according to the first embodiment of the present invention.

FIG. 4 is a graph showing an angle and a reflectance of a polarizing plate used for a light source unit according to the first embodiment of the present invention.

FIG. 5 is a sectional view of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a liquid crystal display device according to a third embodiment of the present invention.

FIG. 7 is a sectional view of a liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 8 is a schematic plan view showing an embodiment in which the present invention is applied to a small information device.

FIG. 9 is a schematic sectional view showing an embodiment in which the present invention is applied to a small information device.

FIG. 10 is a circuit block diagram according to the embodiment of the present invention.

FIG. 11 is a plan view of a liquid crystal display device according to the related art.

FIG. 12 is a cross-sectional view of a liquid crystal display device according to the related art.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 first substrate 2 signal electrode 6 second substrate 7 counter electrode 8 first polarizing plate 9 liquid crystal layer for panel, (scattering liquid crystal layer, guest host liquid crystal layer) 11 second polarizing plate 10 sealing material 12 sealing Material 13 Pixel portion 15 Optical axis 16 Orientation direction of third alignment film 17 Orientation direction of fourth alignment film 18 Optical axis of third polarizing plate 19 Optical axis of fourth polarizing plate 20 Angle of polarizing plate 21 3 substrate 22 lower electrode 23 upper electrode 24 fourth substrate 25 third polarizing plate 26 fourth polarizing plate 27 adhesive layer 28 second sealing material 30 liquid crystal layer for light source 31 spacer 35 light emitting section 36 diffusion layer 37 light quantity Variable light source 41 Watch case 42 Windshield 61 Light source control button 62 Optical sensor

Claims (7)

[Claims] A signal electrode provided on a first substrate;
A liquid crystal display panel, comprising: a counter electrode provided on the first substrate; and a liquid crystal layer for a panel sealed between the first substrate and the second substrate. A liquid crystal display device comprising a variable light amount light source unit including a substrate, a light source liquid crystal layer, and a light emitting unit on a substrate side facing a user of the liquid crystal display panel. 2. A signal electrode provided on a first substrate;
A liquid crystal display panel, comprising: a counter electrode provided on the first substrate; and a liquid crystal layer for a panel sealed between the first substrate and the second substrate. On the substrate side facing the user of the liquid crystal display panel, there is a variable light amount type light source unit including a reflective film for reflecting visible light, a substrate, a liquid crystal layer for a light source, and a light emitting unit. A liquid crystal display device in which light from the user is sometimes reflected to the user by a reflection film of a light source unit. 3. A signal electrode provided on a first substrate;
A liquid crystal display panel, comprising: a counter electrode provided on the first substrate; and a liquid crystal layer for a panel sealed between the first substrate and the second substrate. On the side of the substrate facing the user of the liquid crystal display panel, one of the polarization axes is a transmission axis, and the orthogonal polarization axis is a reflection axis. A liquid crystal display device comprising a variable light amount type light source unit. 4. A signal electrode provided on a first substrate;
A liquid crystal display panel, comprising: a counter electrode provided on the first substrate; and a liquid crystal layer for a panel sealed between the first substrate and the second substrate. On the side of the substrate facing the user of the liquid crystal display panel, the liquid crystal layer for the light source sandwiched between the two substrates and one of the polarization axes provided on the two substrates are the transmission axes, and the orthogonal polarization axes are It has a light amount variable type light source unit consisting of a reflective polarizing plate which is a reflection axis, and the two reflective polarizing plates are at an angle at which the reflection intensity becomes almost maximum when no voltage is applied to the light source liquid crystal layer. A liquid crystal display device characterized by the above-mentioned. 5. The liquid crystal according to claim 1, wherein the variable light amount light source unit varies the light amount by applying a voltage to a light source liquid crystal layer constituting the light source unit. Display device. 6. The panel liquid crystal layer encapsulated between the first substrate and the second substrate is made of a mixed material of a transparent polymer and a liquid crystal. The liquid crystal display device according to any one of the above. 7. The liquid crystal display device according to claim 1, wherein the light source liquid crystal layer constituting the variable light quantity type light source unit is a liquid crystal layer having a memory function.