JP4196976B2 - Liquid crystal display device and electronic apparatus using the same - Google Patents

Description

  The present invention relates to a liquid crystal display device capable of performing a bright monocolor display and an electronic apparatus using the same.

In a liquid crystal display device for monochromatic display, black characters are generally displayed on a white or gray background.
However, due to the recent trend of emphasizing fashion, body colorization is progressing especially in portable electronic devices. In accordance with this trend toward colorization, there is a demand for monochromatic liquid crystal display devices that have a colored background. Background colorization in a liquid crystal display device is possible by incorporating a color film into a liquid crystal display device having a white background color.

  However, since the insertion of the color film involves light absorption, there is a problem that the display becomes dark.

  Moreover, since the color film is formed by stretching in the same manner as a general film material, it has a refractive index anisotropy. Therefore, unintentional coloring may occur.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a liquid crystal display device capable of monocolor display, no unintentional coloring, and the like, and capable of bright display. It is to provide an electronic device used.

A liquid crystal cell formed by enclosing a liquid crystal between a pair of substrates each provided with a transparent electrode on the inner surface side; a polarizer disposed on a first surface side of the liquid crystal cell; A reflective polarizer that is disposed on the second surface side and reflects polarized light having a polarization plane in a reflection axis direction and transmits polarized light having a polarization plane in a transmission axis direction different from the reflection axis direction; and the liquid crystal And a color polarizer disposed between the cell and the reflective polarizer.

  In the liquid crystal display device of the present invention, a color polarizer that is not polarized with respect to a specific color is disposed between the liquid crystal cell and the reflective polarizer. Therefore, the specific color is transmitted through the color polarizer regardless of the controlled state of the liquid crystal cell, is reflected by the reflective polarizer, and returns to the display surface, so that the display is monocolored. In addition, since the reflectance of the reflective polarizer can be adjusted by adjusting the direction of the reflection axis of the reflective polarizer, the brightness of the monochromatic region can be adjusted.

  In addition, since the liquid crystal display device of the present invention uses a reflective polarizer on the back side of the liquid crystal cell as in the case of the above-described invention, the reflective polarizer almost reflects polarized light having a polarization plane in a predetermined direction. can do. Accordingly, a brighter display can be achieved as compared with the case where an absorption type polarizer is used as the back side polarizer and a reflection type liquid crystal display device is formed by arranging a reflective plate by aluminum deposition or the like on the back side. .

More preferably, the liquid crystal display device of the present embodiment further includes a backlight disposed on the backmost side.

  According to the liquid crystal display device of the present invention, the reflective polarizer that reflects the polarized light having the polarization plane in the reflection axis direction and transmits the polarized light in the transmission axis direction different from the reflection axis direction is used. Therefore, although a reflective display is possible, a transmissive display can also be performed by disposing a backlight on the rearmost surface, although a bright reflective display is possible.

  In addition, when a transflective liquid crystal display device using a reflective polarizer as a polarizer used on the back side of the liquid crystal cell is used as a reflective type, when the reflective polarizer is used in a predetermined direction, Since most of the polarized light having the polarization plane is reflected, depending on the controlled state of the liquid crystal cell, the light transmitted through the polarizer on the front side can be almost reflected by the reflective polarizer. Therefore, when the transflective liquid crystal display device using a reflective polarizer is used as a reflective type, an absorption type polarizer is used as a back side polarizer, and a half mirror is disposed on the back side. As compared with the case where a transflective liquid crystal display device is formed, a much brighter display can be performed.

  Further, since the reflective polarizer may be operated as a transflective reflector, the transmission axis of the polarizer arranged on the front side of the liquid crystal cell and the transmission axis of the polarizer arranged on the back side of the liquid crystal cell If the angle between the reflection axis and the transmission axis of the reflective polarizer is appropriately selected, the brightness of the display will be different depending on whether it is used as a reflection type under bright light or as a transmission type when the surrounding is dark. A transflective liquid crystal display device that is not inverted can be formed.

(7) An electronic apparatus according to the present invention includes the liquid crystal display device described above as a display unit. According to the present invention, an electronic apparatus having any one of the effects described above for each of the inventions described above and having a liquid crystal display device that is bright and consumes low power when used as a reflection type can be obtained.

  Hereinafter, preferred embodiments of the present invention will be described more specifically with reference to the drawings.

[First Embodiment]
<Structure of liquid crystal display device>
FIG. 1 is a schematic cross-sectional view showing a liquid crystal display device 10 of the present embodiment. As shown in this figure, the liquid crystal display device 10 is formed by disposing an absorption polarizer 14 on the front side of a liquid crystal cell 18 and a reflective polarizer 40 on the back side of the liquid crystal cell. A color film 34 and a scattering layer 38 are disposed between the liquid crystal cell 18 and the reflective polarizer 40. A backlight 44 is disposed on the back surface of the reflective polarizer 40. In FIG. 1 and other similar drawings, it is illustrated that there is a gap between the elements constituting the liquid crystal display device, but this is for the convenience of illustration, and in fact, the elements are substantially the same as each other. It is in a close contact state.

  The liquid crystal cell 18 includes a substrate 20 on which a striped transparent electrode 22 is formed on one side and a substrate 28 on which a striped transparent electrode 26 is formed on one side by a gap material (not shown) or the like. The transparent electrodes 22 and 26 of the substrates 20 and 28 that are isolated from each other are simple matrix type liquid crystal cells 18 that face each other in a lattice pattern. A TN liquid crystal 24 is filled between the pair of substrates 20 and 28, and the opposing peripheral edges of the substrates 20 and 28 are sealed with a sealing material 30. In FIG. 1, the pair of substrates are drawn widely apart, but this is for clarity of illustration, and the pair of substrates is actually separated by a narrow gap of several μm to several tens of μm. Facing each other.

  The color film 34 is formed by stretch molding using, for example, a material in which a pigment or a dye is mixed in polyvinyl alcohol, polycarbonate, triacetyl cellulose, polyester, polymethyl methacrylate, or the like. When the liquid crystal display device 10 is used in the reflection mode, light passes through the color film 34 twice. Therefore, the color film 34 preferably has a high light transmittance. For example, two types of color films shown in FIG. It is preferable that the minimum transmittance at a wavelength in the visible light region is at least 20% or more as shown in the transmission spectrum for 34 white light. Although FIG. 1 shows an example in which the color film 34 is disposed between the liquid crystal cell 18 and the scattering layer 38, the color film 34 is disposed between the scattering layer 38 and the reflective polarizer 40. It may be arranged between the polarizer 14 and the liquid crystal cell 18.

  Further, since the color film 34 is stretched, it usually has a refractive index anisotropy in which the stretching direction is a slow axis. When the color film 34 is disposed on the back side of the liquid crystal cell 18, the color film 34 is disposed in a state where the slow axis of the color film 34 is parallel to the reflection axis or the transmission axis of the reflective polarizer 40. When arranged on the side, the slow axis of the color film 34 is arranged in parallel with the absorption axis or transmission axis of the polarizer 14.

  The scattering layer 38 has a function of scattering and diffusing light. Although it is possible to omit the scattering layer 38, if this is not present, the display corresponding to the portion reflected by the reflective polarizer 40 becomes a display that gives an impression of the light reflected by the mirror surface. The scattering layer 38 prevents such a state, and makes the display corresponding to the portion reflected by the reflective polarizer 40 a display close to paper white. The scattering layer 38 is formed, for example, as a plastic film in which beads are dispersed. Further, the scattering layer 38 may be formed by mixing beads in adjacent layers, for example, an adhesive layer made of an optical adhesive that bonds the color film 34 and the reflective polarizer 40 together. The scattering layer 38 may be provided between the polarizer 14 and the liquid crystal cell 18 or may be provided on the front surface of the polarizer 14.

  The backlight 44 includes a light source 46 and a light guide plate 48 as shown in FIG. The light emitted from the light source 46 is guided and diffused by the light guide plate 48 so that the light enters all the pixels of the liquid crystal cell 18. As the light guide plate 48, an acrylic plate is usually used, and a plate in which a diffusion plate or a condensing prism is laminated on an acrylic light guide plate may be used. As the light source 46, an LED (light emitting diode) or the like is used. As the backlight, instead of the combination of the light source 46 and the light guide plate 48, an EL (electroluminescent) that is a surface light source may be used.

  The reflective polarizer 40 is the same as the polarization separation element disclosed in International Publication (WO95 / 017692), Japanese Patent Publication No. 9-506985, etc., and satisfies a predetermined relationship with respect to thickness and refractive index characteristics. A pair of layers are stacked in multiple layers. The reflective polarizer 40 is formed of a number of layers each having a thickness of less than 1 μm, and is a thin plate having a thickness of approximately 200 μm as a whole. The reflective polarizer 40 has a property of transmitting polarized light having a polarization plane in the transmission axis direction and reflecting polarized light having a polarization plane in the reflection axis direction substantially orthogonal to the transmission axis. The reflective polarizer 40 and the polarizer 14 are arranged so that the transmission axis of the reflective polarizer 40 and the transmission axis of the polarizer 14 are substantially parallel.

  In addition to the components shown in FIG. 1, the liquid crystal display device 10 includes an alignment film provided facing the liquid crystal 24, a drive circuit, and the like.

<Operation as a reflective liquid crystal display device>
The operation when the liquid crystal display device 10 formed as described above is used as a reflection type under bright light will be described with reference to FIG. In this figure, FIG. 3A on the left half shows a switching state in which the liquid crystal cell 18 rotates the polarization plane of the passing light by 90 °, and FIG. 3B on the right half shows the light passing therethrough. In this case, the liquid crystal cell 18 is in a switching state in which the polarization plane is not rotated.

  First, a case where external light is incident on a switching state region where the liquid crystal cell 18 rotates light by 90 °, that is, a case shown in the left side of FIG. 3A will be described. In this case, when the incident external light 60 passes through the polarizer 14 on the front surface side, it becomes linearly polarized light 60 a having a polarization plane in the direction of the transmission axis 14 T, and the linearly polarized light 60 a is rotated by 90 ° when passing through the liquid crystal cell 18. The linearly polarized light 60b is obtained. The linearly polarized light 60b is colored by the color film 34 and scattered by the scattering layer 38, but enters the reflective polarizer 40 as the linearly polarized light 60c with the polarization direction unchanged. The incident linearly polarized light 60c is reflected by the reflective polarizer 40 because its polarization direction is the same as the reflection axis 40R of the reflective polarizer. The reflected linearly polarized light 60d is linearly polarized light 60d having a polarization plane in the direction of the reflection axis 40R of the reflective polarizer 40, and is again scattered by the scattering layer 38 and colored by the color film 34. It enters the liquid crystal cell as linearly polarized light 60e which does not change. The linearly polarized light 60e is rotated by 90 ° in the liquid crystal cell 18 to become polarized light 60f having a polarization plane parallel to the transmission axis 14T of the polarizer 14 on the front side, so that it passes through the polarizer 14 on the front side and reaches the display surface. .

  As described above, in the liquid crystal display device 10, most of the external light incident on the liquid crystal cell 18 is reflected by the reflective polarizer 40 when the liquid crystal cell 18 is in a switching state in which the light is rotated by 90 °. Since the emission follows the path, the area where the liquid crystal cell 18 is in a switching state in which light is rotated by 90 ° is brightly displayed.

  Next, the case where the external light 65 is incident on the switching region where the liquid crystal cell 18 does not rotate the light, that is, the case shown on the left side of FIG. 3B will be described. In this case, when the incident external light 65 passes through the polarizer 14 on the front surface side, it becomes linearly polarized light 65a having a polarization plane in the direction of the transmission axis 14T. The linearly polarized light 65a passes through the liquid crystal cell 18 as it is, passes through the color film 34 and the scattering layer 38, is colored and scattered, but the polarization direction does not change, but the transmission axis 14T of the polarizer 14 is the linearly polarized light 65b. Is transmitted through the reflective polarizer 40 having the transmission axis 40T parallel to the light and reaches the backlight. Since the surface of the backlight has a low reflectivity, most of the light is absorbed there.

  As described above, in the liquid crystal display device 10, most of the external light 65 that has entered the liquid crystal cell 18 when the liquid crystal cell 18 is in a switching state that does not rotate the light is absorbed by the surface of the backlight and is directed to the display surface side. Since the liquid crystal cell 18 does not return, the region where the liquid crystal cell 18 is in a switching state that does not rotate light is darkly displayed.

  The liquid crystal cell 18 can take an intermediate state between a state where the light is rotated by 90 ° and a state where the light is not rotated. At this time, halftone display is performed.

<Operation as a transmissive liquid crystal display device>
Next, an operation in the case where the liquid crystal display device 10 is used as a transmission type with a dark surrounding will be described with reference to FIG.

  First, the case where the light 70 from the backlight 44 enters the region in the switching state in which the liquid crystal cell 18 rotates the light by 90 °, that is, the case shown on the right side of FIG. In this case, when the light 70 emitted from the backlight 44 is transmitted through the reflective polarizer 40, it becomes linearly polarized light 70a having a polarization plane in the direction of the transmission axis 40T. The linearly polarized light 70a that has passed through the reflective polarizer 40 passes through the scattering layer 38 and the color film 34 and is incident on the liquid crystal cell 18 as linearly polarized light 70b that is scattered and colored without changing the polarization direction. When the linearly polarized light 70 b passes through the liquid crystal cell 18, it becomes a linearly polarized light 70 c rotated 90 °. Most of the linearly polarized light 70c is absorbed by the polarizer 14 having the absorption axis 14A orthogonal to the transmission axis 40T of the reflective polarizer 40.

  As described above, when the liquid crystal display device 10 is used as a transmission type, the light incident on the liquid crystal cell 18 from the backlight 44 in the switching region where the liquid crystal cell rotates 90 ° light is absorbed by the polarizer 14. Therefore, it becomes a dark display area.

  Next, the case where the light from the backlight 44 is incident on the switching state area where the liquid crystal cell 18 does not rotate the light, that is, the case shown on the right side of FIG. 3B will be described. In this case, when the light 75 emitted from the backlight 44 passes through the reflective polarizer 40, it becomes linearly polarized light 75a having a polarization plane in the direction of the transmission axis 40T. The linearly polarized light 75 a is transmitted through the scattering layer 38 and the color film 34 and is incident on the liquid crystal cell 18 as a linearly polarized light 75 b that is scattered and colored without changing the polarization direction. Since the linearly polarized light 75b is in a switching state in which the liquid crystal cell does not rotate light, the linearly polarized light 75b passes through the liquid crystal cell 18 as the linearly polarized light 75b and has a transmission axis 14T parallel to the transmission axis 40T of the reflective polarizer 40. 14 is transmitted and reaches the display surface.

  As described above, when the liquid crystal display device 10 is used as a transmission type, the light from the backlight 44 incident on the liquid crystal cell 18 is transmitted through the reflective polarizer 40 when the liquid crystal cell 18 is in a switching state that does not rotate the light. Since most of the emitted light reaches the display surface, the region where the liquid crystal cell 18 is in a switching state where the light is not rotated is a bright display region.

  As in the reflective display mode, the liquid crystal cell 18 can take an intermediate state between the state where the light is rotated by 90 ° and the state where the light is not rotated in the transmissive display mode. Is done.

  As described above, in the liquid crystal display device 10 of the present embodiment, the region in which the liquid crystal cell 18 rotates 90 ° is bright when the liquid crystal display device 10 is used as a reflection type under bright external light. When the liquid crystal display device 10 is used as a transmission type because the surroundings are dark, the display area is dark. In the liquid crystal display device 10 of the present embodiment, the region where the liquid crystal cell 18 does not rotate the light becomes a dark display region when the liquid crystal display device 10 is used as a reflection type under bright external light, and the surroundings are dark. When the liquid crystal display device 10 is used as a transmission type, a bright display area is obtained.

<Other display characteristics>
As described above, in the liquid crystal display device 10 of the present embodiment, the light in the bright display region is transmitted through the color film 34 and colored, so the bright display region is monochromatic.

  The color film 34 is incorporated in the liquid crystal display device 10 with the slow axis 34D parallel to the reflection axis 40R or the transmission axis 40T of the reflective polarizer 40. (FIG. 3 shows an example in which the slow axis 34D is parallel to the transmission axis 40T of the reflective polarizer 40.) Accordingly, unintentional coloring or the like may occur due to the refractive index anisotropy of the color film 34. Absent.

  Furthermore, since the liquid crystal display device 10 of the present invention uses the reflective polarizer 40 as the polarizer used on the back side of the liquid crystal cell 18, the reflective polarizer 40 reflects almost all polarized light having a polarization plane in a predetermined direction. Depending on the controlled state of the liquid crystal cell 18, the light transmitted through the polarizer 14 on the front side of the liquid crystal cell 18 and the liquid crystal cell 18 can be almost reflected by this reflective polarizer. Therefore, the liquid crystal display device 10 using the reflective polarizer 40 in this way uses an absorption type polarizer as a back side polarizer, and a reflective plate made of aluminum vapor deposition or the like is arranged on the back side of the reflective type liquid crystal display. The display is brighter than when the device is formed. This is because the reflection by the reflective polarizer 40 can reflect almost 100% depending on the state of incident polarized light, as compared with the case where the reflectance of the reflecting plate by aluminum deposition or the like is only 90%. . Furthermore, a normal absorption-type polarizing plate uses a dichroic pigment such as a halogen substance such as iodine or a dye, and the dichroic ratio is not necessarily high, so that 10% or more of light is wasted. However, the reflective polarizer 40 is hardly absorbed by light.

  Further, even when the liquid crystal display device 10 of the present embodiment is formed as a transflective type (both reflection / transmission type), the reflective polarizer 40 has almost no polarized light having a polarization plane in a predetermined direction in the reflection mode. Therefore, depending on the switching state of the liquid crystal cell 18, the light transmitted through the front-side polarizer 14 can be almost reflected by the reflective polarizer 40. Therefore, the transflective liquid crystal display device 10 using the reflective polarizer 40 uses an absorptive polarizer as a back side polarizer and a half mirror is disposed on the back side of the transflective liquid crystal. Compared to the display device, the display is much brighter in the reflective mode.

  As described above, since the liquid crystal display device 10 of the present embodiment uses the reflective polarizer 40, it can display brightly when used as a reflective type, and is in spite of light absorption by the color film. Therefore, a bright display can be performed.

  In the above description, an example in which the liquid crystal display device 10 is formed as a transflective liquid crystal display device 10 is shown. However, the liquid crystal display device of the present embodiment does not use a backlight. Thus, a reflection-only liquid crystal display device may be used.

<Electronic device with liquid crystal display>
4A, 4 </ b> B, and 4 </ b> C are external views illustrating examples of electronic devices using the liquid crystal display device 10 of the present embodiment as a display unit. FIG. 4A shows a mobile phone 88, which includes the liquid crystal display device 10 above the front surface thereof. FIG. 4B shows a wristwatch 92 in which a display unit using the liquid crystal display device 10 is provided in the center of the front surface of the main body. FIG. 4C illustrates a portable information device 96 that includes a display unit including the liquid crystal display device 10 and an input unit 98. In addition to the liquid crystal display device 10, these electronic devices include various circuits such as a display information output source, a display information processing circuit, a clock generation circuit, and a power supply circuit that supplies power to these circuits, although not shown. Consists of including.

  Note that the electronic device in which the liquid crystal display device 10 of the present embodiment is incorporated is not limited to a mobile phone, a watch, and a portable information device, but a notebook personal computer, electronic notebook, pager, calculator, POS terminal, IC card, mini-disc Various electronic devices such as players can be considered.

  These information devices are used in any environment, indoors or outdoors. Therefore, it is preferable that the battery can be driven for a long time. Therefore, the liquid crystal display device 10 used as a display unit of these electronic devices is required to have low power consumption. There is a reflective liquid crystal display device using external light as a display device with low power consumption, but there is a problem that it cannot be used in a dark place. The liquid crystal display device of this embodiment can perform a reflective display with low power consumption at a brightness comparable to that of a conventional reflective liquid crystal display device, and perform a transmissive display when used in a dark place. Can do. Therefore, an electronic device that can perform high-quality display with low power consumption can be formed by using the display portion of these electronic devices.

[Second Embodiment]
In the second embodiment, an STN type liquid crystal cell is used, and a phase difference plate for eliminating the coloring that occurs accompanying the STN type liquid crystal cell is added. And different. Since the other points are the same as in the first embodiment, description thereof is omitted. In the drawings, corresponding parts are denoted by the same reference numerals as in the first embodiment.

  FIG. 5 is a schematic cross-sectional view showing the liquid crystal display device 50 of the present embodiment. As shown in this figure, the liquid crystal display device 50 uses a liquid crystal cell 52 using STN type liquid crystal 53 and includes a retardation plate 54 between the polarizer 14 and the liquid crystal cell 18. The retardation plate 54 can eliminate the coloration generated in the STN liquid crystal cell 52. When the color film 34 is disposed between the polarizer 14 and the liquid crystal cell 18, the retardation film 54 may be disposed on either the front side or the back side of the color film 34.

  When the color film 34 is disposed between the polarizer 14 and the liquid crystal cell 18, the slow axis 34 </ b> D is the absorption axis 14 </ b> A of the polarizer 14, the transmission axis 14 </ b> T, and the slow axis of the retardation plate 54. When the liquid crystal cell 18 and the reflective polarizer 40 are arranged in parallel with at least one of the fast axes, the slow axis 34D is the reflective axis 40R or the transmission axis of the reflective polarizer 40. The liquid crystal display device 50 is incorporated in parallel with 40T. Therefore, unintentional coloring due to the refractive index anisotropy of the color film 34 does not occur.

  The liquid crystal display device of this embodiment can also be formed as a reflection-only liquid crystal display device without using the backlight 44.

[Third Embodiment]
The third embodiment is different from the first embodiment in that a colored scattering layer is used as the scattering layer and no color film is used. Since the other points are the same as in the first embodiment, description thereof is omitted. In the drawings, corresponding parts are denoted by the same reference numerals as in the first embodiment.

  FIG. 6 is a schematic cross-sectional view showing the liquid crystal display device 58 of the present embodiment. As shown in this figure, the liquid crystal display device 58 is provided with a colored scattering layer 60 between the liquid crystal cell 18 and the reflective polarizer 40, and no color film is used. The colored scattering layer 60 is not limited to the position shown in FIG. 6 and may be provided between the polarizer 14 and the liquid crystal cell 18 or may be provided on the front surface of the polarizer 14.

  The colored scattering layer 60 is formed by placing beads (diameter of several μm) having a refractive index larger than that of the pressure-sensitive adhesive in the pressure-sensitive adhesive, and further mixing a pigment or a dye. The colored scattering layer 60 can also be formed by mixing beads (having a diameter of several μm) having a refractive index larger than that of the resin, a pigment, a dye, or the like in the transparent resin.

  When the liquid crystal display device 58 is used in the reflection mode, light passes through the colored scattering layer 60 twice. Therefore, as in the case of the color film in the first embodiment, the colored scattering layer 60 has a light transmittance. For example, the minimum transmittance at a wavelength in the visible light region is preferably at least 20%.

  The colored scattering layer 60 prevents the display corresponding to the portion reflected by the reflective polarizer 40 from becoming a mirror-like display, and can provide a display close to paper white, and light in a region that provides a bright display. Is colored by being transmitted through the colored scattering layer 60, so that a display in which a bright display region is monochromatic can be obtained.

  Since the liquid crystal display device 58 of the present embodiment can be made monochromatic without using a color film, the cost and the number of assembling steps are reduced as compared with the case of using a color film.

  The present embodiment can be similarly applied to the liquid crystal display device of the second embodiment.

  Further, the liquid crystal display device of this embodiment can be formed as a reflection-only liquid crystal display device without using a backlight.

[Fourth Embodiment]
The fourth embodiment is different from the first embodiment in that a polarizer or / and a light semi-absorber are further arranged on the back surface of the reflective polarizer. Since the other points are the same as in the first embodiment, description thereof is omitted. In the drawings, corresponding parts are denoted by the same reference numerals as in the first embodiment.

  FIG. 7 is a schematic cross-sectional view showing the liquid crystal display device 64 of the present embodiment. As shown in this figure, the liquid crystal display device 64 is further provided with a polarizer 66 on the back surface of the reflective polarizer. When the liquid crystal display device 64 is used as a reflection type, by adjusting the absorption axis direction of the polarizer 66 and the transmission axis direction of the reflection polarizer 40, the light transmitted through the reflection polarizer 40 is again transmitted. Since the amount returned to the reflective polarizer 40 can be adjusted, it is possible to adjust the darkness of the display area that is darkly displayed. When the liquid crystal display device 64 is used as a transmission type, the light from the backlight 44 is reflected by adjusting the direction of the absorption axis of the polarizer 66 and the direction of the transmission axis of the reflective polarizer 40. Since the amount of light transmitted through the polarizer 40 can be adjusted, the brightness of a brightly displayed display area can be adjusted.

  Note that, instead of or in addition to the polarizer 66, a light semi-absorber is used, and the light absorptivity of the light semi-absorber is also selected, so that the display becomes dark when the liquid crystal display device 64 is used as a reflection type. It is possible to adjust the darkness of the displayed area and the brightness of the brightly displayed area when the liquid crystal display device 64 is used as a transmission type.

  Note that this embodiment can be similarly applied to the liquid crystal display device of the second embodiment or the third embodiment.

  Further, the liquid crystal display device of this embodiment can be formed as a reflection-only liquid crystal display device without using a backlight.

[Fifth Embodiment]
The fifth embodiment is different from the first embodiment in that a color polarizer is disposed between the liquid crystal cell and the reflective polarizer, and no color film is used. Since the other points are the same as in the first embodiment, description thereof is omitted. In the drawings, the same reference numerals are given to portions corresponding to the first embodiment.

  FIG. 8 is a schematic cross-sectional view showing the liquid crystal display device 70 of the present embodiment. As shown in this figure, the liquid crystal display device 70 is formed with a color polarizer 72 between the liquid crystal cell 18 and the reflective polarizer 40. Further, in this figure, an example in which the scattering layer 38 is located between the color polarizer 72 and the reflective polarizer 40 is shown.

  In the liquid crystal display device 70, a color polarizer 72 having no polarization with respect to a specific color is disposed between the liquid crystal cell 18 and the reflective polarizer 40. Therefore, when the liquid crystal display device 70 is used in the reflective mode, the specific color is transmitted through the color polarizer 72 and reflected by the reflective polarizer 40 regardless of the controlled state of the liquid crystal cell 18. In order to return to the display surface, the display is monochromatic. Further, since the reflectance of the reflective polarizer 40 can be adjusted by adjusting the angle of the reflection axis of the reflective polarizer 40, the brightness of the background color and the color density of the background color can be adjusted. .

  Further, the liquid crystal display device of this embodiment can be formed as a reflection-only liquid crystal display device without using a backlight.

[Sixth Embodiment]
The sixth embodiment is different from the first embodiment in that a polarizer is further disposed between the liquid crystal cell and the reflective polarizer. Note that the liquid crystal display device of this embodiment is used as a transflective (reflective / transmissive) type liquid crystal display device, and is always formed with a backlight disposed on the backmost side. Since these points and points other than those described below are the same as those in the first embodiment, description thereof will be omitted. In the drawings, corresponding parts are denoted by the same reference numerals as in the first embodiment.

  FIG. 9 is a schematic cross-sectional view showing the liquid crystal display device 76 of the present embodiment. As shown in this figure, the liquid crystal display device 76 is formed by arranging a polarizer 78 between the liquid crystal cell 18 and the reflective polarizer 40. In this figure, an example in which the color film 34 and the scattering layer 38 are provided between the polarizer 78 and the reflective polarizer 40 is shown.

  Since the liquid crystal display device 76 performs a reflective display by using the reflective polarizer 40, a bright reflective display is possible. Thus, the monochromatic liquid crystal display device 76 can be displayed.

  Further, since the reflective polarizer 40 may be operated as a transflective reflector, the transmission axis of the polarizer 14 disposed on the front side of the liquid crystal cell 18 and the polarizer 78 disposed on the back side of the liquid crystal cell. If the angle between the transmission axis and the reflection axis or the transmission axis of the reflective polarizer 40 is appropriately selected, it can be used as a reflection type under bright light or as a transmission type when the surrounding is dark. Thus, it is possible to form a transflective (reflection / transmission type) liquid crystal display device in which the brightness of the display is not reversed.

  The present embodiment can be similarly applied to the liquid crystal display devices of the second embodiment and the third embodiment.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications may be made within the scope of the gist of the present invention or the equivalent scope of the claims. Is possible.

  For example, in each of the above-described embodiments, an example of a simple matrix type liquid crystal display device has been described. However, the liquid crystal display device is a static drive type liquid crystal display device that performs segment display or the like, or three-terminal switching represented by TFT. An active matrix liquid crystal display device using a two-terminal switching element represented by an element or MIM may be used.

  In each of the above embodiments, a laminated type is used as the reflective polarizer. However, the reflective polarizer is not limited to this type, and is a combination of a cholesteric liquid crystal layer and a quarter-wave plate (Japanese Patent Laid-Open No. Hei. 8-278992), which uses Brewster's angle to separate reflected polarized light and transmitted polarized light (SID 92 DIGEST P.427-429), and those using holograms can also be used.

  Further, in each of the above embodiments, an example in which the transmission axis and the reflection axis of the reflective polarizer are orthogonal to each other has been shown. However, the transmission axis and the reflection axis are not necessarily orthogonal if the direction is different.

  In each of the above embodiments, the liquid crystal cell has an example in which the optical rotation in the switching state corresponding to the bright display is 90 ° and the optical rotation in the switching state corresponding to the dark display is 0 °. However, the optical rotation of the liquid crystal cell is not limited to this, and it is sufficient that the optical rotation in the switching state corresponding to the bright display and the optical rotation in the switching state corresponding to the dark display differ by approximately 90 °.

1 is a schematic cross-sectional view of a liquid crystal display panel according to a first embodiment. It is a graph which shows the transmission spectral spectrum of two types of color films. It is explanatory drawing which shows the operation | movement of the liquid crystal display device of 1st Embodiment divided into reflection and transmissive mode, (A) shows the case where a liquid crystal cell rotates 90 degree light, (B) shows liquid crystal The case where a cell does not rotate light is shown. It is an external view which shows the electronic device using the liquid crystal display device of 1st Embodiment, (A) is a mobile telephone, (B) is a wristwatch, (C) is a portable information device. It is typical sectional drawing of the liquid crystal display panel which concerns on 2nd Embodiment. It is typical sectional drawing of the liquid crystal display panel which concerns on 3rd Embodiment. It is typical sectional drawing of the liquid crystal display panel which concerns on 4th Embodiment. It is typical sectional drawing of the liquid crystal display panel which concerns on 5th Embodiment. It is typical sectional drawing of the liquid crystal display panel which concerns on 6th Embodiment.

Explanation of symbols

10, 50, 58, 64, 70, 76 Liquid crystal display device 14, 66, 78 Polarizer 18, 52 Liquid crystal cell 20, 28 Substrate 22, 26 Transparent electrode 24 Liquid crystal 34 Color film 38 Scattering layer 40 Reflective polarizer 44 Backlight 54 Phase difference plate 68 Light semi-absorber 72 Color polarizer 88 Mobile phone (electronic equipment)
92 Watch (electronic equipment)
96 Portable information devices (electronic devices)

Claims (3)

A liquid crystal cell formed by enclosing a liquid crystal between a pair of substrates each provided with a transparent electrode on the inner surface side;
A polarizer disposed on the first surface side of the liquid crystal cell;
Reflected polarized light that is disposed on the second surface side of the liquid crystal cell, reflects polarized light having a polarization plane in the reflection axis direction, and transmits polarized light having a polarization plane in the transmission axis direction different from the reflection axis direction. With the child,
A color polarizer disposed between the liquid crystal cell and the reflective polarizer;
A liquid crystal display device comprising:   The liquid crystal display device according to claim 1, further comprising a backlight disposed on the backmost side.   An electronic apparatus comprising the liquid crystal display device according to claim 1 as a display unit.

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