JP2003262886A - Liquid crystal display device and electronic appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent defective conduction caused by sinking of a conductive material such as a soldering ball into the side of a cholestric liquid crystal layer side in the case of mounting an electric part for connection to a conduction part formed on a substrate having the cholestric liquid crystal layer formed thereon in a liquid crystal display device having the cholestric liquid crystal layer formed on the substrate. <P>SOLUTION: The liquid crystal display device 10 has a liquid crystal cell 11 in which a liquid crystal layer 16 is inserted and held between an upper substrate 14 and a lower substrate 13 adhered to each other with a seal material in the state of opposing each other, a first conductive part 32 is formed on the inner face side of the lower substrate 13, and a second conductive part 25 is formed on the inner face side of the upper substrate 14. A transflective layer 18 having the cholestric liquid crystal layer is formed between the lower substrate 13 and the first conductive part 32. An electronic part 32b is mounted on the outside of the seal material 15 on the inner face side of the upper substrate 14. The electronic part 32b is electrically connected with the second conductive part 25 and electrically connected with the first conductive part 32 via a conduction part between the substrates. <P>COPYRIGHT: (C)2003,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 and electronic equipment, and more particularly, to a solder ball or the like when mounting an electronic component for connecting to a conductive portion formed on a substrate provided with a cholesteric liquid crystal layer. The present invention relates to a configuration of a liquid crystal display device capable of preventing defective conduction caused by a conductive material penetrating into a cholesteric liquid crystal layer side.

[0002]

2. Description of the Related Art Reflective liquid crystal display devices have low power consumption because they do not have a light source such as a backlight, and have been widely used in various portable electronic devices. However,
The reflective liquid crystal display device uses external light such as natural light or illumination light for display, and thus has a problem that it is difficult to visually recognize the display in a dark place. Therefore, there has been proposed a liquid crystal display device in which outside light is used in a bright place like a normal reflection type liquid crystal display device, and a display can be visually confirmed by an internal light source in a dark place. In other words, this liquid crystal display device employs a display system that has both a reflective type and a transmissive type, and the power consumption can be reduced by switching the display mode to either the reflective mode or the transmissive mode according to the ambient brightness. It is possible to perform a clear display even when the surroundings are dark while reducing the number. Hereinafter, in this specification, this type of liquid crystal display device is referred to as a “semi-transmissive reflective liquid crystal display device”.

As a form of the transflective liquid crystal display device,
A reflective film having a slit (opening) for light transmission formed on a metal film such as aluminum is referred to as an inner surface of the lower substrate (hereinafter, in this specification, a surface of the substrate on the liquid crystal side is an inner surface, and a surface opposite to the outer surface is an outer surface). Therefore, a liquid crystal display device in which this reflective film functions as a semi-transmissive reflective film has been proposed. In this liquid crystal display device, by providing a metal film on the inner surface of the lower substrate, the influence of parallax due to the thickness of the lower substrate is prevented,
In particular, the structure using color filters has the effect of preventing color mixing.

FIG. 8 shows an example of a transflective liquid crystal display device using this type of transflective film.

In this liquid crystal display device 100, a liquid crystal 103 is sandwiched between a pair of transparent substrates 101 and 102,
A reflective film 104 and an insulating film 106 are laminated on the lower substrate 101, and indium tin oxide (Indium Tin Oxide,
Hereinafter, a lower electrode 108 made of a transparent conductive film such as ITO) is formed, and an alignment film 107 is formed so as to cover the lower electrode 108. On the other hand, a color filter 109 having R (red), G (green), and B (blue) dye layers is formed on the upper substrate 102, and the planarizing film 1 is formed thereon.
11 are stacked, an upper electrode 112 made of a transparent conductive film such as ITO is formed on the flattening film 111, and an alignment film 113 is formed so as to cover the upper electrode 112.

The reflection film 104 is formed of a metal film having a high light reflectance such as aluminum.
A slit 110 for light transmission is formed for each pixel. Due to this slit 110, the reflective film 104 functions as a semi-transmissive reflective film (henceforth, this film is referred to as a semi-transmissive reflective film). Further, on the outer surface side of the upper substrate 102, a front scattering plate 118, a retardation plate 119, and an upper polarizing plate 114 are arranged in this order from the upper substrate 102 side, and the lower substrate 10
A quarter wave plate 115 and a lower polarizing plate 116 are provided on the outer surface side of 1.
Are provided in this order. In addition, the backlight 117
The (illuminator) is the lower surface of the lower substrate 101, and the lower polarizing plate 116.
It is located further below.

When the liquid crystal display device 100 shown in FIG. 8 is used in a reflective mode in a bright place, external light such as sunlight or illumination light incident from above the upper substrate 102 is reflected by the liquid crystal 103.
Of the semi-transmissive reflective film 104 on the lower substrate 101, and then the liquid crystal 103 again to pass through the upper substrate 102.
It is emitted to the side. Further, when used in the transmission mode in a dark place, the light emitted from the backlight 117 installed below the lower substrate 101 passes through the reflection film 104 at the slit 110 and then passes through the liquid crystal 103. Then, the light is emitted to the upper substrate 102 side. These lights contribute to the display in each mode.

By the way, as a reflective layer of such a reflective liquid crystal display device, a metal film having a high light reflectance such as aluminum or silver has been conventionally used. On the other hand, in recent years, dielectric mirrors in which dielectric thin films having different refractive indexes are alternately laminated, cholesteric reflectors using cholesteric liquid crystals, hologram reflectors using hologram elements, and the like have been proposed. These reflectors not only serve as reflectors that reflect light by taking advantage of the characteristics of the constituent materials, but also have other functions.

Among them, the cholesteric liquid crystal exhibits a liquid crystal phase at a certain temperature (liquid crystal transition temperature) or more, and in the liquid crystal phase, liquid crystal molecules have a periodic spiral structure with a constant pitch. This structure has a property of selectively reflecting light having a wavelength matching the pitch of the helix and transmitting other light. Therefore, since the pitch of the helix can be controlled by, for example, the intensity of ultraviolet rays and the temperature during curing, the color of the reflected light can be locally changed, and it is also used as a reflective color filter. Further, by stacking a plurality of cholesteric liquid crystal layers that selectively reflect color lights of different colors, it is possible to eventually function as a reflection plate that reflects white light.

[0010]

However, in the reflection type liquid crystal display device using the cholesteric liquid crystal layer as described above, in order to connect to a conductive portion such as an electrode provided on the substrate on which the cholesteric liquid crystal layer is formed. In order to mount the electronic components of the above on the inner surface of the substrate, COG (Chip On
When a mounting process such as mounting is performed, the hardness of the cholesteric liquid crystal layer is not sufficient to withstand the pressure applied in the mounting process, so conductive particles such as solder balls sneak into the cholesteric liquid crystal layer side. In some cases, poor conduction may occur, resulting in a decrease in yield and a problem in product reliability. Such a problem is not limited to a passive matrix type or active matrix type reflective liquid crystal display device using a cholesteric liquid crystal layer, but a passive matrix type or active matrix type transflective type liquid crystal display device using a cholesteric liquid crystal layer. Similar problems occur in liquid crystal display devices.

Further, in the conventional transflective liquid crystal display device as shown in FIG. 8, although the display can be visually recognized regardless of the presence or absence of external light, the display in the transmissive mode is more visible than in the reflective mode. There was a problem that the brightness was much worse. This is because the display in the transmissive mode uses only half of the light emitted from the backlight for display, uses only the light that has passed through the slit of the semi-transmissive reflective film, and the lower substrate. Is a problem caused by the fact that a quarter wavelength plate and a lower polarizing plate are provided on the outer surface side of the above.

In the conventional transflective liquid crystal display device, the display mode is different between when the light is reflected and when the light is transmitted, and particularly when transmitted, approximately half of the light emitted from the backlight is absorbed by the upper polarizing plate. , Only the other half is used for display. That is, in the reflective mode, the linearly polarized light incident from the upper substrate side is used as it is for bright display, whereas in the transmissive mode, the display is performed from the lower surface of the liquid crystal layer in order to perform display as in the reflective mode. It is necessary that the light traveling toward the substrate side is substantially circularly polarized light. However, half of the circularly polarized light is absorbed by the upper polarizing plate when it is emitted from the upper substrate, and as a result, only approximately half of the light incident on the liquid crystal layer contributes to the display. become. As described above, there is a factor that the display in the transmission mode becomes dark due to the display principle. Further, since the display is performed by using the light transmitted through the slit in the transmission mode, the ratio of the area of the slit to the entire area of the semi-transmissive reflective film (that is, the aperture ratio)
Controls the brightness of the display. If this aperture ratio is increased,
The display in the transmissive mode can be brightened, but if the aperture ratio is increased, the area of the non-aperture portion of the semi-transmissive reflective film is reduced, and the display in the reflective mode becomes dark. Therefore, the aperture ratio of the slit cannot be increased to a certain extent or more in order to secure the brightness in the reflection mode, and there is a limit in improving the brightness in the transmission mode.

Next, in the transflective liquid crystal display device, a quarter wavelength plate is required on the outer surface side of the lower substrate due to its display principle. The reason why the brightness in the transmissive mode is insufficient is as follows. Explained. However, in the following description, a configuration will be described in which dark display is performed when a non-selection voltage is applied and bright display is performed when a selection voltage is applied.

First, in the liquid crystal display device 100 shown in FIG. 8, when performing dark display in the reflection mode, the upper substrate 10 is used.
When the transmission axis of the upper polarizing plate 114 is parallel to the paper surface, the light incident from the outside of the upper polarizing plate 11 of the upper polarizing plate 11
4 becomes linearly polarized light having a polarization axis parallel to the paper surface, and while being transmitted through the liquid crystal 103, it becomes almost circularly polarized light due to the birefringence effect of the liquid crystal 103. And the lower substrate 1
When it is reflected by the surface of the semi-transmissive reflective film 104 on 01, it becomes circularly polarized light in the reverse direction, and when it again passes through the liquid crystal 103, it becomes linearly polarized light having a polarization axis perpendicular to the paper surface and reaches the upper substrate 102. Here, the upper polarizing plate 114 of the upper substrate 102 is
Since it is a polarizing plate having a transmission axis parallel to the paper surface, the light reflected by the semi-transmissive reflection film 104 is absorbed by the upper polarizing plate 114 and does not return to the outside (viewer side) of the liquid crystal display device 100, and the liquid crystal The display device 100 is darkly displayed.

On the contrary, in the case of performing the bright display in the reflection mode, since the orientation direction of the liquid crystal 103 is changed when the selection voltage is applied to the liquid crystal 103, the external light incident from the outside of the upper substrate 102 is incident on the liquid crystal 103. Of the upper substrate 1 of the upper substrate 102 is linearly polarized light when it is transmitted, and is reflected by the semi-transmissive reflection film 104 as it is, and is linearly polarized light having a polarization axis parallel to the paper surface.
After passing through 14, the light returns to the outside (observer side), and the liquid crystal display device 100 is brightly displayed. On the other hand, the liquid crystal display device 100
In the case of performing the display in the transmission mode, the light emitted from the backlight 117 enters the liquid crystal cell from the outside of the lower substrate 101, and the light passing through the slit 110 contributes to the display. Become light. Here, in order to perform the dark display in the liquid crystal display device 100, as described above, the light traveling from the slit 110 to the upper substrate 102 needs to be substantially circularly polarized light as in the reflection mode. Therefore, since the light emitted from the backlight 117 and passing through the slit 110 needs to be substantially circularly polarized light, 1 / (1) for converting the linearly polarized light after passing through the lower polarizing plate 116 into substantially circularly polarized light. The four-wave plate 115 is required. The quarter-wave plate is a plate capable of converting linearly polarized light into substantially circularly polarized light at a certain wavelength.

Here, among the light emitted from the backlight 117, focusing on the light that does not pass through the slit 110, the light is emitted from the backlight 117 and the lower polarizing plate 116.
When the transmission axis of is set to be perpendicular to the paper surface, it becomes a linearly polarized light which is perpendicular to the paper surface at the time of passing through the lower polarizing plate 116, and then becomes 1/4.
By passing through the wave plate 115, it becomes almost circularly polarized light and reaches the semi-transmissive reflective film 104. Further, the semi-transmissive reflective film 104
When it is reflected from the lower surface of the, it becomes circularly polarized light of the opposite direction, and again becomes 1
When it passes through the / 4 wavelength plate 115, it becomes linearly polarized light having a polarization axis parallel to the paper surface. Then, this linearly polarized light is absorbed by the lower polarizing plate 116 having a transmission axis perpendicular to the paper surface. That is, of the light emitted from the backlight 117, the light that has not passed through the slit 110 is reflected on the lower surface of the semi-transmissive reflective film 104, and then the lower polarizing plate 1 of the lower substrate 101.
Almost everything is absorbed by 16.

As described above, in the transflective liquid crystal display device 100, almost all the light reflected by the transflective film 104 without passing through the slit 110 in the transmissive mode is in the lower polarizing plate 116 of the lower substrate 101. Therefore, only part of the light emitted from the backlight 117 can be used for display. That is, the lower polarizing plate 1
If the light is transmitted through the lower polarization plate 116 without being absorbed by 16, and returns to the backlight 117, the brightness of the backlight 117 is effectively improved by the light originally emitted from the backlight 117 and the returned light. Therefore, the brightness of the transmission mode can be improved. In other words, if the light reflected by the semi-transmissive reflective film 104 without passing through the slit 110 can be reused for display, the brightness of the transmissive mode can be improved. However, that cannot be realized with the conventional configuration.

The present invention has been made to solve the above problems, and in a liquid crystal display device in which a cholesteric liquid crystal layer is provided on a substrate, a conductive portion formed on the substrate provided with the cholesteric liquid crystal layer is used. An object of the present invention is to provide a liquid crystal display device capable of preventing a conduction failure due to a conductive material such as a solder ball penetrating into the cholesteric liquid crystal layer side when mounting an electronic component for connection.

Another object of the present invention is to provide a liquid crystal display device in which a cholesteric liquid crystal layer functions as a semi-transmissive reflective layer, and particularly to provide a liquid crystal display device having improved visibility in a transmissive mode and excellent in visibility. And

Further, there is no decrease in yield due to poor continuity between the conductive portion formed on the substrate provided with the cholesteric liquid crystal layer and the electronic parts connected to the conductive portion, and the electronic equipment is provided with a liquid crystal display device having improved reliability. The purpose is to provide.

Another object of the present invention is to provide an electronic apparatus equipped with the above liquid crystal display device which has a bright display in the transmission mode and has excellent visibility.

[0022]

In order to achieve the above object, in a liquid crystal display device of the present invention, a liquid crystal layer is sandwiched between an upper substrate and a lower substrate which face each other and are bonded by a sealing material. A liquid crystal display device having a liquid crystal cell in which a first conductive portion is provided on the inner surface side of the lower substrate and a second conductive portion is provided on the inner surface side of the upper substrate, the liquid crystal display device comprising: A reflection layer having a cholesteric liquid crystal layer that reflects at least a part of the elliptically polarized light having a predetermined rotation direction is provided between the first conductive portion and the first conductive portion, and the elliptically polarized light is applied to the liquid crystal layer from the upper substrate side. Is provided with the upper substrate side elliptically polarized light incidence means, and the liquid crystal layer reverses the polarity of the elliptically polarized light that is incident in either the selective electric field applied state or the non-selective electric field applied state, and in the other state. very The electronic component is mounted outside the sealing material on the inner surface side of the upper substrate, and the electronic component is electrically connected to the second conductive portion and is connected to the first conductive portion. Is electrically connected via a board-to-board conducting portion.

The "first conductive portion" and the "second conductive portion" referred to here are, for example, data lines, scanning lines and the like in an active matrix type liquid crystal display device, or a passive matrix type liquid crystal display device. Refers to electrodes such as segment electrodes and common electrodes. Further, an example of an active matrix liquid crystal display device is
One of the conductive portion and the second conductive portion is a data line and the other is a scanning line.

The "electronic component" specifically refers to a drive IC, a capacitor, etc. used in a drive circuit of a liquid crystal display device.

Further, the first conductive portion and the second conductive portion may include a lead wiring portion for connecting to the electronic component and a connecting wiring portion.

Further, in the present invention, both the light introduced into the liquid crystal layer from the upper substrate side and the lower substrate side is "elliptical polarized light", but it is actually "circular polarized light". However, the above light does not necessarily have to be perfectly circularly polarized light, and may be “elliptical polarized light” in a broad sense. Further, the light reflected by the cholesteric liquid crystal layer is "elliptical polarized light having a predetermined rotation direction", but actually it is approximately "circular polarized light having a predetermined rotation direction". However, the light reflected by the cholesteric layer does not necessarily have to be perfect circularly polarized light, and may be "elliptic polarized light" in a broad sense.

In the liquid crystal display device of the present invention having the above structure, the reflective layer has a cholesteric liquid crystal layer that reflects a part of elliptically polarized light having a predetermined rotation direction and transmits a part of the elliptically polarized light. A lower substrate-side elliptically polarized light incident unit that is a layer and that allows elliptically polarized light to be incident from the lower substrate side may be provided. Such a liquid crystal display device can be a transflective liquid crystal display device.

By the way, the cholesteric liquid crystal layer of the reflective layer or the semi-transmissive reflective layer provided in the liquid crystal display device is coated with cholesteric liquid crystal on the rubbing-treated alignment film by various coating methods such as a spin coating method, and then ultraviolet rays. By controlling the pitch of the spirals of the liquid crystal molecules by controlling the intensity of ultraviolet rays and the temperature when irradiating and curing the liquid crystal, the liquid crystal molecules adopt a periodic spiral structure with a constant pitch, and a predetermined rotation direction. Of the elliptically polarized light having a predetermined rotation direction, or a part of the elliptically polarized light having a predetermined rotation direction and a part of the elliptically polarized light having a predetermined rotation direction are transmitted.

However, in order to mount an electronic component for connecting to the first conductive portion on the inner surface of the lower substrate on which such a cholesteric liquid crystal layer is formed, a COG (Chip On) is mounted.
When a mounting process such as glass mounting is performed, the hardness of the cholesteric liquid crystal layer does not have a hardness that can withstand the pressure applied in the mounting process. Therefore, the conductive particles (conductive material) such as solder balls are cholesteric liquid crystal. It may sink into the layer side and cause poor conduction.

Therefore, in the present invention, the electronic component electrically connected to the first conductive portion and the second conductive portion provided on the lower substrate is connected to the substrate on which the cholesteric liquid crystal layer is not provided, that is, Since the electronic component is not mounted on the cholesteric liquid crystal layer by mounting the electronic component on the upper substrate side, the electronic component and the first and second conductive parts connected thereto can be surely conducted. Therefore, it is possible to improve the yield and the quality of products.

Further, the first conductive portion provided on the lower substrate and the electronic component provided on the upper substrate side can be electrically connected to each other via the inter-substrate conductive portion.

Further, according to the present invention, the electronic parts are mounted on one side of the liquid crystal cell by mounting the electronic parts on the same side of the upper substrate, and the electronic parts are mounted on the remaining three sides. It is not necessary to provide a region for mounting the frame, and the width of the frame can be made uniform in the left-right direction or in the vertical direction, and it is possible to realize a small-sized liquid crystal display device with a narrow frame. Here, the frame means a portion outside the display area of the liquid crystal cell, that is, a non-display area.

The cholesteric liquid crystal used in the present invention has so-called selective reflectivity that selectively reflects circularly polarized light having a wavelength equal to the helical pitch of liquid crystal molecules and the same rotation direction as the spiral winding direction. There is. Conversely,
Light having a wavelength not equal to the helical pitch of the liquid crystal molecules, and circularly polarized light having a rotation direction opposite to the spiral winding direction even though the wavelength is equal to the helical pitch of the liquid crystal molecules pass through the cholesteric liquid crystal. Further, the cholesteric liquid crystal layer used in the present invention has a wavelength equal to the helical pitch of liquid crystal molecules,
It has a function of reflecting at least a part of circularly polarized light in the same rotation direction as the spiral winding direction. Therefore, in the case of a cholesteric liquid crystal layer that has a wavelength equal to the helical pitch of liquid crystal molecules and reflects all circularly polarized light in the same rotation direction as the spiral winding direction, it functions as a reflective layer and the wavelength is the helical pitch of liquid crystal molecules. And a cholesteric liquid crystal layer that reflects a part of circularly polarized light in the same rotation direction as the spiral winding direction, it functions as a semi-transmissive reflective layer.

The cholesteric liquid crystal layer used in the present invention has a wavelength equal to the helical pitch of the liquid crystal molecules and reflects a part of circularly polarized light in the same rotation direction as the spiral winding direction,
It may have a function of partially transmitting light, and such a cholesteric liquid crystal layer functions as a semi-transmissive reflective layer.

When the reflective layer made of cholesteric liquid crystal, which has been recently proposed in the reflective liquid crystal display device, is used, the present inventors set the polarization state of the light incident on the liquid crystal cell to elliptically polarized light, and select it for the liquid crystal layer. If the liquid crystal mode is set so that the polarity of the elliptically polarized state is reversed when an electric field is applied or when a non-selective electric field is applied, the display mode can be the same for reflection and transmission. I found that the transmission mode can be prevented from becoming dark. Also,
It was found that the light reflected to the lower substrate side by the selective reflection of the cholesteric liquid crystal can be reused while keeping the structure of the outer surface side of the lower substrate as the conventional one. Focusing on these points, the inventors have come to propose the configuration of the present invention.

The display principle when the liquid crystal display device of the present invention is used as a semi-transmissive reflective type and the reason why the light reflected by the semi-transmissive reflective layer can be reused will be described with reference to FIG. The display principle when the liquid crystal display device of the present invention is used as a reflective type is almost the same as the reflective bright display and the reflective dark display when used as a semi-transmissive reflective type.

FIG. 4 is a diagram for explaining the display principle of the liquid crystal display device of the present invention.

A liquid crystal layer 16 is sandwiched between an upper substrate 14 and a lower substrate 13 which are a pair of translucent substrates, and a liquid crystal cell 11 is provided.
Is configured. A semi-transmissive reflective layer 18 made of a cholesteric liquid crystal layer is provided on the inner surface side of the lower substrate 13. The cholesteric liquid crystal layer reflects a part of circularly polarized light having a predetermined rotation direction and transmits a part of the circularly polarized light. In the present description, for example, a clockwise circularly polarized light (hereinafter referred to as right circularly polarized light) , 80% is reflected and 20% is transmitted.

Further, the liquid crystal display device of the present invention comprises the liquid crystal layer 1.
6 is provided with an upper-substrate-side elliptically-polarized light incident means for making the elliptically-polarized light incident from the upper-substrate 14 side. In FIG. 4, an upper-polarizing plate 36 that transmits linearly polarized light in one direction and the upper-polarizing plate 3 are provided.
The upper quarter-wave plate 35 that converts the linearly polarized light that has passed through 6 into circularly polarized light constitutes the upper substrate side elliptically polarized light incidence means.
Further, in FIG. 4, lower substrate side elliptically polarized light incidence means for making elliptically polarized light incident on the liquid crystal layer 16 from the lower substrate 13 side is also provided.
The quarter-wave plate 27 constitutes the lower substrate side elliptically polarized light incidence means. Here, on both the upper substrate 14 side and the lower substrate 13 side, the transmission axis of the polarizing plate is set to a direction parallel to the paper surface of FIG. 4, and when linearly polarized light in this direction is incident on the ¼ wavelength plate, right circularly polarized light is generated. It shall be emitted. The upper quarter wave plate 35
Alternatively, any retardation plate may be used, and in this case, this retardation plate may have a function of converting linearly polarized light that has passed through the upper polarizing plate 36 into circularly polarized light. Further, an arbitrary retardation plate may be used in place of the lower quarter wave plate 27, and in this case, this retardation plate has a function of converting linearly polarized light transmitted through the upper polarizing plate 28 into circularly polarized light. If you have.

The liquid crystal layer 16 is for reversing the direction of rotation of the circularly polarized light that has entered depending on whether or not a selective electric field is applied. For example, when a non-selective voltage is applied (when the liquid crystal is OFF), for example, λ / Therefore, the incident right circularly polarized light is changed to left circularly polarized light and left circularly polarized light is changed to right circularly polarized light after passing through the liquid crystal layer. On the other hand, the phase difference disappears when the selection voltage is applied (when the liquid crystal is ON), and the rotation direction of the circularly polarized light does not change.

In the liquid crystal display device shown in FIG. 4, when bright display in the reflection mode is performed (left end in FIG. 4), the upper substrate 1
The light incident from the outside of the upper plate 4 is the upper polarizing plate 3 on the upper substrate 14.
By passing through 6, the light becomes linearly polarized light having a polarization axis parallel to the paper surface, and then through the upper 1/4 wavelength plate 35, it becomes right circularly polarized light. At this time, if the liquid crystal is turned on, the rotation direction of the circularly polarized light does not change as described above. Therefore, when the right circularly polarized light is incident on the liquid crystal layer 16, this light passes through the liquid crystal layer 16 and is semi-transmissive. Even when it reaches the reflective layer 18, it remains as right circularly polarized light.

Here, the major difference between the conventional semi-transmissive reflective layer using a metal film or the like and the semi-transmissive reflective layer 18 of the present invention using a cholesteric liquid crystal is in the case of a semi-transmissive reflective layer made of a metal film. The rotation direction of circularly polarized light is reversed during reflection, that is, when right circularly polarized light is reflected, it changes to left circularly polarized light, whereas in the case of the semi-transmissive reflective layer 18 using cholesteric liquid crystal, the rotational direction of circularly polarized light is The point is that it does not change, that is, even if the right circularly polarized light is reflected, it remains the right circularly polarized light. Therefore, after 80% of the right circularly polarized light is reflected by the semi-transmissive reflective layer 18 on the lower substrate, it is transmitted through the liquid crystal layer 16 toward the upper substrate again. At this time, since the liquid crystal is in the ON state, the polarization state remains the right circularly polarized light, but
After that, by passing through the upper quarter-wave plate 35, it is changed to linearly polarized light having a polarization axis parallel to the paper surface, and this linearly polarized light can pass through the upper polarizing plate 36, so that the outside (viewer side)
Then, the liquid crystal display is displayed brightly.

On the contrary, when the dark display in the reflection mode is performed (second from the right in FIG. 4), the liquid crystal is turned off.
Since the liquid crystal layer has a phase difference of λ / 2, right circularly polarized light incident from the upper substrate side becomes left circularly polarized light when transmitted through the liquid crystal layer. In FIG. 4, since the cholesteric liquid crystal that constitutes the semi-transmissive reflective layer reflects only part of the right circularly polarized light, the left circularly polarized light passes through the semi-transmissive reflective layer. After that, the light passes through the lower quarter-wave plate and changes to linearly polarized light having a polarization axis perpendicular to the paper surface. This linearly polarized light is absorbed by the lower polarizing plate, so it does not return to the outside (observer side). , The liquid crystal display device is darkly displayed.

On the other hand, when performing display in the transmission mode, for example, light emitted from a backlight or the like enters the liquid crystal cell 11 from the outside of the lower substrate 13, and this light becomes light that contributes to display. Here, when dark display in the transmissive mode is performed (right end in FIG. 4), almost the same action as in the reflective mode occurs from the lower substrate 13 side toward the upper substrate 14 side.
That is, in FIG.
Since the lower polarizing plate 28 and the lower quarter wavelength plate 7 similar to those on the lower side are provided, right circularly polarized light is incident on the liquid crystal layer 16 from the lower substrate 28 side, and 20% thereof is transmitted through the semi-transmissive reflective layer 18. To do.
Here, if the liquid crystal is in the OFF state, it becomes left-handed circularly polarized light when it reaches the upper substrate 14 side, and is changed to linearly polarized light having a polarization axis perpendicular to the paper surface by passing through the upper ¼ wavelength plate 35. Since this linearly polarized light is absorbed by the upper polarizing plate 36, it is not emitted to the outside (observer side), and the liquid crystal display device is displayed darkly.

When performing bright display in the transmission mode (second from the left in FIG. 4), the light incident from the lower substrate 13 side has a polarization axis parallel to the paper surface by passing through the lower polarizing plate 28. It becomes linearly polarized light, and then passes through the lower quarter wave plate 27 to be emitted as right circularly polarized light. 20% of the emitted light can be transmitted through the semi-transmissive reflective layer 18 made of cholesteric liquid crystal, and emitted as right circularly polarized light. When the liquid crystal is in the ON state, 20% of right circularly polarized light reaches the upper substrate 14 side while maintaining the polarized state. After that, the right-handed circularly polarized light passes through the upper ¼ wavelength plate to be changed into linearly polarized light having a polarization axis parallel to the paper surface, and this linearly polarized light can pass through the upper polarizing plate 36. Then, the liquid crystal display is displayed brightly.

On the other hand, in the transmissive mode bright display, 80% of the right-handed circularly polarized light is reflected by the semi-transmissive reflective layer 18 made of cholesteric liquid crystal. At this time, as described above, the cholesteric liquid crystal has a property of not changing the rotation direction of the reflected circularly polarized light, and therefore the reflected light is right circularly polarized light. Therefore, after that, the right circularly polarized light is converted into the lower quarter wave plate 2.
After passing through 7, the light becomes linearly polarized light having a polarization axis parallel to the paper surface, and this linearly polarized light can be transmitted through the lower polarizing plate 28 having the transmission axis parallel to the paper surface. In this way, when linearly polarized light having the same polarization axis as the transmission axis of the lower polarizing plate 28 is emitted from the lower substrate side 13, this light is reflected by, for example, the reflection plate 40 provided in the backlight 12. Thus, it can be reintroduced to the liquid crystal cell side and reused for display.

Although not described above, the light incident from the lower substrate 13 side even in the dark display of the transmission mode is transmitted through the lower polarizing plate 13 to form a straight line having a polarization axis parallel to the paper surface. It becomes polarized light, and then passes through the lower quarter wave plate 27 to be emitted as right circularly polarized light. 80% of this right-handed circularly polarized light is reflected by the semi-transmissive reflective layer 18 made of cholesteric liquid crystal, and the liquid crystal cell 1 is temporarily transferred from the lower substrate 13 side.
After being emitted to the outside of No. 1, the light is again introduced into the liquid crystal cell 11, but since this light is absorbed by the upper polarizing plate 36 in any case, there is no particular problem for dark display. Also, in the case of bright display in the reflection mode, 2
Since 0% of the light is transmitted through the semi-transmissive reflective layer 18, it is once emitted from the lower substrate 13 side to the outside of the liquid crystal cell 11 and then introduced again into the liquid crystal cell. Since this light contributes to the display, the display in the reflection mode can be kept bright.

As described above, in the liquid crystal display device of the present invention, the same display mode can be used at the time of reflection and at the time of transmission. Especially, when attention is paid to the bright display in the transmission mode, the conventional transflective liquid crystal display is used. Unlike the device, part of the light incident from the lower substrate side is not absorbed by the upper polarizing plate, and almost all the light transmitted through the semi-transmissive reflective layer made of cholesteric liquid crystal contributes to the display. On the other hand, the light reflected by the semi-transmissive reflective layer made of cholesteric liquid crystal can be reused for display. Of course, the ratio of reflection: 80% and transmission: 20% in the cholesteric liquid crystal used in the above description is just an example, and the ratio of reflection and transmission can be changed in any way. However, at any ratio, the effect of being able to maximize the use of circularly polarized light transmitted through the semi-transmissive reflective layer made of cholesteric liquid crystal and being able to reuse the circularly polarized light reflected by the semi-transmissive reflective layer for display is provided. Together, the brightness of transmissive display can be improved as compared with the conventional one while maintaining the brightness of reflective display, and a transflective liquid crystal display device having excellent visibility can be realized.

In the above description, the light introduced from the upper substrate side and the lower substrate side are both “(right) circularly polarized” as an ideal form, but the operation of the liquid crystal display device of the present invention described above is described. In order to realize it, the circularly polarized light does not necessarily have to be perfect circularly polarized light, and may be “elliptically polarized light” in a broad sense.

In the transflective liquid crystal display device of the present invention having any one of the above configurations, it is desirable to provide an illuminating device that allows light to enter the liquid crystal cell from the lower substrate side.

In order to make the transmissive display mode the same as the reflective display mode in the semi-transmissive liquid crystal display device of the present invention, it is necessary to make elliptically polarized light incident from the lower substrate side by some means. Any means may be adopted for that purpose, but by providing an illuminating device that allows light to enter the liquid crystal cell from the lower substrate side, that is, a backlight, it is possible to easily realize a configuration in which elliptically polarized light is incident from the lower substrate side. be able to.

In the liquid crystal display device of the present invention having any one of the above configurations, as a specific mode of the upper substrate side elliptically polarized light incidence means, a polarizing plate that transmits linearly polarized light in one direction,
It can be configured with a retardation plate that converts linearly polarized light that has passed through this polarizing plate into elliptically polarized light.

In the semi-transmissive reflection type liquid crystal display device of the present invention having any one of the above constitutions, as a concrete mode of the lower substrate side elliptically polarized light incidence means, a polarizing plate which transmits linearly polarized light in one direction is used. , And a retardation plate for converting linearly polarized light transmitted through this polarizing plate into elliptically polarized light.

By using two optical members such as the above polarizing plate and the above retardation plate, it is possible to easily convert the external light such as sunlight and illumination light and the illumination light from the backlight into elliptically polarized light. It can be made suitable for the liquid crystal display device of the present invention.

As the retardation plate, one having an arbitrary retardation may be appropriately selected, but it is preferable to use a quarter wavelength plate.

When such a quarter-wave plate is used, the linearly polarized light emitted from the polarizing plate can be converted into circularly polarized light among the elliptically polarized light in a broad sense, so that the light utilization efficiency is the highest. Therefore, a brighter liquid crystal display device can be realized. However, if you want the retardation plate provided on the upper substrate side to also have the function of color compensation, 1 /
The wave plate is not limited to the four-wave plate, and a phase plate having an arbitrary phase difference may be selected. In the liquid crystal display device of the present invention having any one of the above configurations, the reflective layer or the semi-transmissive reflective layer may include a plurality of cholesteric liquid crystal layers having different helical pitches of liquid crystal molecules. The cholesteric liquid crystal layer having such a structure can function as a so-called white reflector, which is a reflective layer that reflects circularly polarized light including various wavelength bands.

In the liquid crystal display device of the present invention, the cholesteric liquid crystal layer selectively reflects color light having different wavelengths according to the spiral pitch of the liquid crystal molecules in each predetermined region divided in the display region of the liquid crystal cell. A reflective color filter that functions as a reflective color filter may be used.

In the cholesteric liquid crystal layer in the liquid crystal display device of the present invention, the helical pitch of the liquid crystal molecules is changed for each predetermined area dividing the display area of the liquid crystal cell, and light having a wavelength corresponding to the helical pitch of the area is selected. If the light is selectively reflected, it is possible to function as a reflective color filter that reflects, for example, red (R), green (G), and blue (B) light in each region. When it functions as a reflective color filter, it is possible to perform color display of different colors for each dot in the display area. In this case, the cholesteric liquid crystal layer mainly functions as a color filter for reflective display.

In the liquid crystal display device of the present invention having any one of the above constitutions, the reflection layer or the semi-transmissive reflection layer,
A color filter layer having a plurality of dye layers containing pigments of different colors may be provided between the first conductive portion and the first conductive portion.

According to the liquid crystal display device having such a configuration,
Color display is possible.

Further, when the liquid crystal display device of the present invention is a semi-transmissive reflective type, it is possible to realize a semi-transmissive reflective type liquid crystal display device which is improved in the brightness of the color display particularly in the transmissive mode and is excellent in visibility. .

In the liquid crystal display device of the present invention having any one of the above configurations, the inter-substrate conducting portion may be provided in the peripheral portions of the upper substrate and the lower substrate which face each other or in the sealing material. An example of the case where the inter-substrate conductive portion is provided in the seal material is a mixture of a conductive material such as anisotropic conductive particles in the seal material. As the anisotropic conductive particles here, particles exhibiting conductivity in the thickness direction of the seal material and not exhibiting conductivity in the width direction of the seal material can be used.

The electronic equipment of the present invention is characterized by including the liquid crystal display device of the present invention having any one of the above configurations.

According to this structure, the liquid crystal display device of the present invention is provided which is capable of surely conducting the electronic part and the conductive portion connected thereto without mounting the electronic part on the cholesteric liquid crystal layer. As a result, it is possible to provide an electronic component having improved reliability without a decrease in yield due to poor continuity between the electronic component and a conductive portion connected thereto. Further, by providing the liquid crystal display device of the present invention which is miniaturized by narrowing the frame, it is possible to realize an electronic device having a wide display area despite its small size and excellent portability.

Further, by providing the liquid crystal display device of the present invention in which the frame width is bilaterally symmetrical, it is possible to make the width of both sides (vertical or horizontal) of the display section using this liquid crystal display device uniform. Therefore, it is possible to realize a good-looking electronic device.

Further, in the case where the semi-transmissive reflection type liquid crystal display device of the present invention is provided in the display section, an electronic device equipped with a liquid crystal display section which is bright in display in the transmission mode and has excellent visibility is provided. Can be provided.

[0067]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment: Liquid Crystal Display Device] A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a diagram showing a partial cross-sectional structure of the liquid crystal display device of this embodiment, and FIG. 2 is a plan view of a liquid crystal cell of the liquid crystal display device of the first embodiment as seen from the lower substrate side. FIG. 3 is a diagram for explaining the display principle of the liquid crystal display device of the first embodiment. The present embodiment is an example of an active matrix type transflective color liquid crystal display device using a thin film diode (TFD) as a switching element. In all of the following drawings, in order to make the drawings easy to see, the film thicknesses, the dimensional ratios, and the like of the respective constituent elements are appropriately changed.

The liquid crystal display device 10 of the present embodiment is shown in FIG.
As shown in, the liquid crystal cell 11 and the backlight 12 (illumination device) are provided. In the liquid crystal cell 11, a lower substrate 13 and an upper substrate 14 are arranged to face each other with a sealing material 15 interposed therebetween, and an STN (Super Twisted Nematic) liquid crystal or the like is provided in a space surrounded by the upper substrate 14, the lower substrate 13, and the sealing material 15. A liquid crystal layer 16 composed of
The backlight 12 is arranged on the rear surface side (the outer surface side of the lower substrate 13).

On the inner surface side of the lower substrate 13 made of a translucent material such as glass or plastic, a semi-transmissive reflective film 18 in which an alignment film and a cholesteric liquid crystal layer are alternately formed is formed.

The plurality of cholesteric liquid crystal layers provided on the semi-transmissive reflective film 18 have different helical pitches of liquid crystal molecules. For example, the helical pitch of liquid crystal molecules is 450
A layer of about nm has blue light, a layer of about 550 nm has green light,
The layer of about 650 nm selectively reflects red light and selectively reflects white light as a whole. Each cholesteric liquid crystal layer reflects and partially transmits circularly polarized light having a predetermined rotation direction. In the present embodiment, for example, clockwise circularly polarized light (hereinafter, referred to as right circularly polarized light). Of these, 80% is reflected and 20% is transmitted. Therefore, the entire semi-transmissive reflection film 18 has a function of reflecting 80% of white right-handed circularly polarized light and transmitting 20% thereof.

The thickness of the semi-transmissive reflective film 18 is, for example, 5
It is about 20 μm.

In order to form the semi-transmissive reflective film 18, for example, an alignment film is applied on a glass plate, a plastic sheet or the like which constitutes the lower substrate 13, the alignment film is rubbed, and then the A solution containing a cholesteric liquid crystal is applied to the surface of the alignment film by various coating methods such as a spin coater, and then, the solution is irradiated with ultraviolet rays to be cured to form a cholesteric liquid crystal layer. Here, by controlling the intensity of ultraviolet rays, temperature, etc. when irradiating with ultraviolet rays to cure, the pitch of the spirals of the liquid crystal molecules is controlled so that the liquid crystal molecules have a periodic spiral structure at a constant pitch.
Then, with the formation of the alignment film subjected to such a rubbing treatment,
By repeating the formation of the cholesteric liquid crystal layer alternately, the target semi-transmissive reflective film 18 is obtained.

An overcoat layer (not shown) made of a translucent resin material or the like is formed on the upper surface of the semi-transmissive reflective film 18. On the upper surface of this overcoat layer, R
A color filter layer 30 in which dye layers of (red), G (green), and B (blue) are repeatedly formed in order is provided, and a color filter layer 30 (a pigment layer containing a pigment) is formed thereon. A flattening film 31 for flattening the step is stacked. Then, a large number of strip-shaped scanning lines (first conductive portions) 32 made of a transparent conductive film such as ITO extend on the flattening film 31 in the lateral direction (direction parallel to the paper surface) in the drawing, An alignment film (not shown) made of polyimide or the like is laminated on the scanning line 32.

On the outer surface side of the lower substrate 13, a lower 1/4
A wave plate 27, a lower polarization plate 28, and a reflection polarization plate 29 are provided in this order. In the present embodiment, the lower substrate side elliptically polarized light incidence means for causing the elliptically polarized light to be incident on the liquid crystal layer 16 from the lower substrate 13 side includes the lower polarizing plate 28 and the lower quarter wave plate 2.
It is composed of 7. In this embodiment, the lower polarizing plate 2
The transmission axis of 8 is parallel to the paper surface of FIG. 3, and when the linearly polarized light in this direction is incident on the lower ¼ wavelength plate 27, right circularly polarized light is emitted. An arbitrary retardation plate may be used in place of the lower quarter-wave plate 27. In this case, this retardation plate has a function of converting linearly polarized light transmitted through the upper polarizing plate 28 into circularly polarized light. If you have.

On the other hand, on the inner surface side of the upper substrate 14 made of a translucent material such as glass or plastic, a large number of strip-shaped data lines (second conductive portions) 25 made of a transparent conductive film such as ITO are formed on the lower side. Scanning line (first conductive portion) 32 on the substrate 13
And extends so as to be orthogonal to
On the other hand, a large number of pixel electrodes 26 are connected via TFD elements (not shown). The TFD element is, for example, a first conductive film made of a tantalum film, an insulating film made of a tantalum oxide film formed by anodization on the surface of the first conductive film, and a chromium film formed on the surface of the insulating film. , A second conductive film made of a metal film of aluminum, titanium, molybdenum, or the like. Then, the first conductive film of the TFD element is connected to the data line 25, and the second conductive film is connected to the pixel electrode 26. And FIG.
As shown in FIG. 5, the leading wirings (second conductive portions) 25a connected to the data lines 25 are formed in the outer left and right regions (left and right frames) of the sealing material 16 of the upper substrate 14, respectively.

These data line 25, pixel electrode 26, TF
An alignment film (not shown) made of polyimide or the like is laminated so as to cover the D element.

On the outer surface side of the upper substrate 14, an upper 1/4
A wave plate 35 and an upper polarizing plate 36 are provided in this order from the substrate side. In the present embodiment, the upper substrate side elliptically polarized light incident means for making the elliptically polarized light incident on the liquid crystal layer 16 from the upper substrate 14 side are the upper quarter wavelength plate 35 and the upper polarizing plate 36.
It consists of and. In the present embodiment, the transmission axis of the upper polarizing plate 36 is parallel to the paper surface of FIG. 3, and when linearly polarized light in this direction is incident on the upper ¼ wavelength plate 35, right circularly polarized light is emitted. ing. The upper quarter wave plate 35
Alternatively, any retardation plate may be used, and in this case, this retardation plate may have a function of converting linearly polarized light that has passed through the upper polarizing plate 36 into circularly polarized light.

In the seal material 15, a particle size of 5 is used as a conductive material.
An inter-substrate conduction part is provided by mixing anisotropic conductive particles (not shown) of about μm. As the anisotropic conductive particles, particles having conductivity in the thickness direction of the seal material 15 but not conductivity in the width direction of the seal material can be used. The inter-substrate conductive portion is connected to the scanning line 32 provided on the lower substrate 13 side.

A data line driver IC (electronic component) 25b for supplying a display signal to the data line 25 and a scanning signal to the scanning line 32 are provided outside the sealing material on the inner surface side of the upper substrate 14. The scanning line driver IC (electronic component) 32b is mounted by COG. The data line driver ICs 25b are provided on both sides of the scanning line driver IC 32b. The data line driver IC (electronic component) 25b and the scanning line driver IC (electronic component) 32b are provided on the same side of the upper substrate 14 as shown in FIG.

Further, outside the seal material on the inner surface side of the upper substrate 14, an IC (electronic component) 32b for the scanning line driver and an inter-substrate conduction portion (not shown) provided in the seal material 15 are provided.
Is provided with a connection wiring portion 32a.

The data line driver IC 25b is electrically connected to the data line 25 by being connected to the lead-out wiring (second conductive portion) 25a via conductive particles (not shown) such as solder balls. ing.

Further, the scanning line driver IC 32b is connected to the inter-substrate conducting portion provided in the above-mentioned sealing material 15 through the conductive particles 32c such as solder balls,
It is electrically connected to the scanning line 32 connected to this inter-substrate connecting portion.

The liquid crystal layer 16 is for reversing the rotation direction of the circularly polarized light which is incident depending on the presence / absence of application of a selective electric field. Therefore, the incident right circularly polarized light is changed to left circularly polarized light after passing through the liquid crystal layer, and left circularly polarized light is changed to right circularly polarized light. On the other hand, the phase difference disappears when the selection voltage is applied (when the liquid crystal is ON), and the rotation direction of the circularly polarized light does not change.

The backlight 12 has a light source 37, a reflecting plate 38, and a light guide plate 39, and the lower surface of the light guide plate 39 (the side opposite to the liquid crystal panel 1) transmits through the light guide plate 39. A reflection plate 40 for emitting light toward the liquid crystal cell 11 side is provided.

The display principle of the liquid crystal display device of this embodiment and the reason why the light reflected by the semi-transmissive reflection layer can be reused will be described below with reference to FIG. Here, a case will be described in which, when the light entering the liquid crystal cell from the outside of the upper substrate 14 and the outside of the lower substrate 13 enters the color filter layer 30, it enters the R dye layer.

In the liquid crystal display device of the present embodiment shown in FIG. 3, when bright display in the reflection mode is performed (the left end of FIG. 3).
The light incident from the outside of the upper substrate 14 is
The light passes through the upper polarizing plate 36 to become linearly polarized light having a polarization axis parallel to the paper surface, and then passes through the upper ¼ wavelength plate 35 to become right circularly polarized light. At this time, when the liquid crystal is kept in the ON state, the rotation direction of the circularly polarized light does not change as described above. Therefore, when the right circularly polarized light is incident on the liquid crystal layer, this light passes through the liquid crystal layer 16 and the color filter layer 30. Even after reaching the semi-transmissive reflective layer 18, the circularly polarized light remains right circularly polarized.

Therefore, after 80% of the red right circularly polarized light obtained by passing the right circularly polarized light through the R dye layer is reflected by the semi-transmissive reflective layer 18 on the lower substrate 13, the liquid crystal is again directed to the upper substrate 14. It will pass through layer 16. At this time as well, since the liquid crystal is in the ON state, the polarization state remains unchanged as right-handed circularly polarized light, but thereafter it changes to linearly polarized light having a polarization axis parallel to the paper surface by passing through the upper ¼ wavelength plate 35. Since this linearly polarized light can pass through the upper polarizing plate 36, it returns to the outside (observer side) and the liquid crystal display device displays bright (red).

On the contrary, in the case of performing the dark display in the reflection mode (second from the right in FIG. 3), if the liquid crystal is turned off,
Since the liquid crystal layer 16 has a phase difference of λ / 2, right circularly polarized light incident from the upper substrate 14 side becomes left circularly polarized light when transmitted through the liquid crystal layer 16. In FIG. 3, the cholesteric liquid crystal forming the semi-transmissive reflective layer 18 reflects only a part of the right circularly polarized light, so that the left circularly polarized light passes through the semi-transmissive reflective layer 18. After that, by passing through the lower quarter wave plate 27, it is changed to linearly polarized light having a polarization axis perpendicular to the paper surface,
Since this linearly polarized light is absorbed by the lower polarization plate 28, it does not return to the outside (observer side), and the liquid crystal display device displays a dark image.

On the other hand, when displaying in the transmission mode, the light emitted from the backlight 12 enters the liquid crystal cell 11 from the outside of the lower substrate 13, and this light becomes the light contributing to the display. Here, when dark display in the transmissive mode is performed (right end in FIG. 3), substantially the same action as in the reflective mode occurs from the lower substrate side to the upper substrate side. That is, in FIG. 3, the lower polarizing plate 2 is the same as the upper substrate side on the lower substrate side.
8 and the lower quarter wave plate 27 are provided, right circularly polarized light is incident on the liquid crystal layer 16 from the lower substrate side, and 20% thereof is transmitted through the semi-transmissive reflective layer 16. Here, if the liquid crystal is in the OFF state, it becomes left-handed circularly polarized light when it reaches the upper substrate side, and changes to linearly polarized light having a polarization axis perpendicular to the paper surface by passing through the upper ¼ wavelength plate 35, Since this linearly polarized light is absorbed by the upper polarizing plate 36, it is not emitted to the outside (observer side), and the liquid crystal display device is displayed darkly.

When the bright display in the transmission mode is performed (second from the left in FIG. 3), the light incident from the lower substrate side is transmitted through the lower polarizing plate 28 to form a straight line having a polarization axis parallel to the paper surface. It becomes polarized light, and then passes through the lower quarter wave plate 27 to be emitted as right circularly polarized light. 20% of the emitted light can be transmitted through the semi-transmissive reflective layer 18 made of cholesteric liquid crystal, further transmitted through the dye layer of the color filter layer 30, and emitted as red right circularly polarized light. When the liquid crystal is in the ON state, 20% of right circularly polarized light reaches the upper substrate 14 side while maintaining the polarized state. After that, the right-handed circularly polarized light passes through the upper quarter-wave plate 35 to be changed into linearly polarized light having a polarization axis parallel to the paper surface, and this linearly polarized light can pass through the upper polarizing plate 36. ), The liquid crystal display is displayed bright (red).

On the other hand, in the transmissive mode bright display, 80% of the right-handed circularly polarized light is reflected by the semi-transmissive reflective layer 18 made of cholesteric liquid crystal. At this time, as described above, the cholesteric liquid crystal has a property of not changing the rotation direction of the reflected circularly polarized light, and therefore the reflected light is right circularly polarized light. Therefore, after that, the right circularly polarized light is converted into the lower quarter wave plate 2.
After passing through 7, the light becomes linearly polarized light having a polarization axis parallel to the paper surface, and this linearly polarized light can be transmitted through the lower polarizing plate 28 having the transmission axis parallel to the paper surface. In this way, when linearly polarized light having the same polarization axis as the transmission axis of the lower polarizing plate 28 is emitted from the lower substrate side, this light is reflected by the reflection plate 40 provided in the backlight 12 to thereby cause a liquid crystal cell. It can be reintroduced on the side and reused for display.

As described above, in the liquid crystal display device of the present embodiment, the same display mode can be used during reflection and during transmission, and particularly when attention is paid to the bright display in the transmission mode, the conventional transflective liquid crystal is used. Unlike the display device, part of the light incident from the lower substrate side is not absorbed by the upper polarizing plate, and almost all the light transmitted through the semi-transmissive reflective layer 18 made of cholesteric liquid crystal contributes to the display. On the other hand, the light reflected by the semi-transmissive reflective layer 18 made of cholesteric liquid crystal can be reused for display.

Therefore, in the liquid crystal display device of this embodiment, the circularly polarized light transmitted through the semi-transmissive reflective layer 18 made of cholesteric liquid crystal can be utilized to the maximum extent, and the semi-transmissive reflective layer 18 can be utilized.
The effect of being able to reuse the circularly polarized light reflected by the display for display combined with the effect of improving the brightness of the transmissive display while maintaining the brightness of the reflective display, and a semi-transmissive reflective liquid crystal with excellent visibility A display device can be realized.

Further, in the liquid crystal display device of this embodiment,
A scanning line driver IC 32b connected to the scanning line 32 provided on the lower substrate 13, and a data line driver IC 25 electrically connected to the data line 25 provided on the upper substrate 14.
By mounting b on the substrate on which the semi-transmissive reflective layer 18 having a plurality of cholesteric liquid crystal layers is not provided, that is, on the upper substrate 14 side, the scanning line driver IC 32b and the like are mounted on the cholesteric liquid crystal layer. Since the electronic component of No. 1 is not mounted, the scanning line driver IC 32b and the scanning line 32 connected to the scanning line driver IC 32b can be surely conducted, and the yield and the product quality can be improved.

The scanning line 32 provided on the lower substrate 13
And scan line driver IC 32b provided on the upper substrate 14
Can be electrically connected to each other via the inter-substrate conducting portion provided in the sealing material 15.

Further, in the present embodiment, by mounting the scanning line driver IC 32b and the data line driver IC 25b on the same side of the upper substrate 14, electronic components are mounted on one side of the liquid crystal cell 11. It is not necessary to provide a region for mounting electronic components on the remaining three sides, and the width of the frame 11a can be equalized to the left and right or to the top and bottom, and a liquid crystal display device with a narrow frame can be realized. It is possible.

In the liquid crystal display device of the above embodiment, the semi-transmissive reflective layer 18 having a plurality of cholesteric liquid crystal layers reflects a part of the white circularly polarized light in the same rotation direction as the spiral winding direction, and Although the case of having a function of transmitting the liquid crystal cell has been described, a reflective color filter that selectively reflects color light having different wavelengths according to the spiral pitch of liquid crystal molecules in each predetermined area that is divided in the display area of the liquid crystal cell 11. It may be provided with a cholesteric liquid crystal layer having a function as.

[Electronic Equipment] Examples of electronic equipment equipped with the liquid crystal display device of the above-described embodiment will be described.

FIG. 5 is a perspective view showing an example of a mobile phone. In FIG. 5, reference numeral 1000 indicates a mobile phone main body, and reference numeral 1001 indicates a liquid crystal display unit using the above liquid crystal display device.

FIG. 6 is a perspective view showing an example of a wrist watch type electronic device. In FIG. 6, reference numeral 1100 indicates a watch body, and reference numeral 1101 indicates a liquid crystal display unit using the above liquid crystal display device.

FIG. 7 is a perspective view showing an example of a portable information processing device such as a word processor and a personal computer. In FIG. 7, reference numeral 1200 is an information processing apparatus, reference numeral 1202 is an input unit such as a keyboard, reference numeral 1204 is an information processing apparatus main body, and reference numeral 1206 is a liquid crystal display unit using the above liquid crystal display device.

The electronic equipment shown in FIGS. 5 to 7 does not have to be mounted with the electronic components such as the scanning line driver IC 32b on the inner surface of the lower substrate 13 provided with the cholesteric liquid crystal layer, and the electronic components and the electronic components connected thereto can be connected. The liquid crystal display device 10 of the present embodiment, which can surely conduct the first conductive portion such as the scanning line 32, is provided in the liquid crystal display portion, so that the electronic component and the first conductive portion connected to the electronic component are provided. It is possible to provide an electronic device with improved reliability, which can reduce a decrease in yield due to poor conduction of parts.

Further, by providing the liquid crystal display device 10 of the present embodiment which is miniaturized by narrowing the frame, an electronic device having a wide display area despite the small size of the entire device and excellent portability is realized. can do.

Further, by providing the liquid crystal display device 10 of the present embodiment having a bilaterally symmetrical frame width in the liquid crystal display portion, the width of both sides (for example, left and right) of the liquid crystal display portion using the liquid crystal display device 10 can be improved. Can be made even, and a good-looking electronic device can be realized.

Further, by providing the liquid crystal display device 10 of the present embodiment in the liquid crystal display section, it is possible to realize an electronic apparatus having a display section capable of obtaining a bright display in the transmission mode.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

The present invention is similar to the above-described embodiment in TFD.
The thin film transistor (Thin Film Transistor) is not limited to the active matrix type transflective liquid crystal display device that uses
It is also possible to apply to a transflective liquid crystal display device using the above, and a passive matrix type transflective liquid crystal display device, and the reflective liquid crystal display device is not limited to the transflective liquid crystal display device. Is also applicable to
The present invention can be applied not only to a color liquid crystal display device but also to a monochrome liquid crystal display.

[0109]

As described above in detail, according to the liquid crystal display device of the present invention, the sealing material on the inner surface side of the upper substrate without the reflective layer having the cholesteric liquid crystal layer or the semi-transmissive reflective layer is provided. An electronic component is mounted on the outside, the electronic component is electrically connected to the second conductive portion, and is electrically connected to the first conductive portion via an inter-board conductive portion, When mounting an electronic component for connecting to a conductive portion formed on a substrate provided with a cholesteric liquid crystal layer, it is possible to prevent a conduction failure due to a conductive material such as a solder ball penetrating into the cholesteric liquid crystal layer side. Further, according to an electronic device provided with such a liquid crystal display device, there is no reduction in yield due to poor conduction between the conductive portion formed on the substrate provided with the cholesteric liquid crystal layer and the electronic components connected thereto, An electronic device including a liquid crystal display device with improved reliability can be provided.

Further, according to the liquid crystal display device of the present invention, which is provided with a semi-transmissive reflective layer having a cholesteric liquid crystal layer for reflecting a part of elliptically polarized light having a predetermined rotation direction and transmitting a part thereof, It is possible to obtain a liquid crystal display device having improved visibility in the transmissive mode and having excellent visibility. Further, according to the electronic device provided with such a liquid crystal display device, it is possible to provide an electronic device provided with the liquid crystal display device having a bright display in the transmission mode and excellent visibility.

[Brief description of drawings]

FIG. 1 is a diagram showing a partial cross-sectional structure of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a plan view of a liquid crystal cell of the liquid crystal display device according to the first embodiment as viewed from a lower substrate side.

FIG. 3 is a diagram for explaining a display principle of the liquid crystal display device according to the first embodiment.

FIG. 4 is a diagram for explaining a display principle of the liquid crystal display device of the present invention.

FIG. 5 is a perspective view showing an example of an electronic device according to the present invention.

FIG. 6 is a perspective view showing another example of an electronic device according to the present invention.

FIG. 7 is a perspective view showing still another example of an electronic device according to the present invention.

FIG. 8 is a partial cross-sectional structural view showing an example of a conventional liquid crystal display device.

[Explanation of symbols]

10 Liquid crystal display device 11 Liquid crystal cell 11a frame 12 Backlight (illuminator) 13 Lower substrate 14 Upper substrate 15 Seal material 16 Liquid crystal layer 18 Semi-transmissive reflective film 25 data line (second conductive part) 25a Lead wiring (second conductive portion) 25b Data line driver IC (electronic component) 26 pixel electrodes 27 Lower quarter wave plate 28 Lower polarizing plate 30 color filter layer 31 flattening film 32 scan lines (first conductive part) 32a connection wiring section 32b Scan line driver IC (electronic component) 32c conductive particles (conductive material) 35 Upper 1/4 wave plate 36 Upper polarizing plate 1000 Cellular phone body (electronic device) 1001, 1101, 1206 Liquid crystal display unit 1100 Watch body (electronic device) 1200 Information processing device (electronic device)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/13363 G02F 1/13363 F term (reference) 2H049 BA02 BA04 BA05 BA07 BA42 BA43 BB03 BC22 2H089 HA02 JA01 KA02 QA02 QA12 QA16 RA10 TA02 TA07 TA14 TA15 2H091 FA01Y FA08X FA08Z FA11X FA11Z FA12Y FA14Y FB02 FC01 FC23 FD06 FD22 FD23 GA02 GA06 GA16 HA10 JA01 LA02 LA12 LA16 LA30 2H092 GA32.

Claims (10)

[Claims] 1. A liquid crystal layer is sandwiched between an upper substrate and a lower substrate, which face each other and are bonded by a sealing material, and a first conductive portion is provided on the inner surface side of the lower substrate. A liquid crystal display device having a liquid crystal cell in which a second conductive portion is provided on an inner surface side, wherein at least at least one of elliptically polarized lights having a predetermined rotation direction is provided between the lower substrate and the first conductive portion. A reflection layer having a cholesteric liquid crystal layer for reflecting a part is provided, and an upper substrate side elliptically polarized light incidence means for making elliptically polarized light incident on the liquid crystal layer from the upper substrate side is provided,
The liquid crystal layer is one that reverses the polarity of the elliptically polarized light that is incident in one of the selected electric field applied state and the non-selected electric field applied state, and does not change the polarity in the other state. An electronic component is mounted on the outside of the sealing material, the electronic component is electrically connected to the second conductive portion, and is electrically connected to the first conductive portion via an inter-board conductive portion. A liquid crystal display device characterized in that 2. The reflection layer is a semi-transmissive reflection layer having a cholesteric liquid crystal layer that reflects a part of elliptically polarized light having a predetermined rotation direction and transmits a part of the elliptically polarized light. The liquid crystal display device according to claim 1, further comprising an elliptically-polarized light incident unit on the lower substrate side which makes polarized light incident. 3. The liquid crystal display device according to claim 2, further comprising an illuminating device that allows light to enter the liquid crystal cell from the lower substrate side. 4. The upper substrate-side elliptically polarized light incident means includes a polarizing plate that transmits linearly polarized light in one direction and a retardation plate that converts the linearly polarized light that has passed through the polarizing plate into elliptically polarized light. The liquid crystal display device according to any one of claims 1 to 3. 5. The lower substrate-side elliptically polarized light incident means includes a polarizing plate that transmits linearly polarized light in one direction and a retardation plate that converts the linearly polarized light that has passed through the polarizing plate into elliptically polarized light. The liquid crystal display device according to any one of claims 2 to 4. 6. The cholesteric liquid crystal layer functions as a reflective color filter that selectively reflects color light having different wavelengths according to the spiral pitch of liquid crystal molecules in each predetermined region divided in the display region of the liquid crystal cell. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is a liquid crystal display device. 7. A color filter layer having a plurality of dye layers containing pigments of different colors is provided between the reflective layer or the semi-transmissive reflective layer and the first conductive portion. The liquid crystal display device according to claim 1. 8. The liquid crystal display according to claim 1, wherein the reflective layer or the semi-transmissive reflective layer has a plurality of cholesteric liquid crystal layers having different helical pitches of liquid crystal molecules. apparatus. 9. The liquid crystal according to claim 1, wherein the inter-substrate conducting portion is provided in the peripheral portions of the upper substrate and the lower substrate facing each other or in the sealing material. Display device. 10. An electronic apparatus comprising the liquid crystal display device according to claim 1. Description: