JP2000081616A - Display device and electronic apparatus using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody a display device of a translucent reflection type which makes display easily visible. SOLUTION: The display device which makes display by utilizing external light and the light from a light source includes a TN liquid crystal panel 10, a polarizing plate 14 and polarized light separator 16 arranged on both sides of the TN liquid crystal panel 10 across the panel and the light source arranged on the side of the polarized light separator 16 opposite to the TN liquid crystal panel 10. The polarized light separator 16 has a function to allow the transmission of the external light and the light from the light source or the reflection thereof according to the polarized light components thereof. A colored film 160 which colors the light from the light source is disposed between the light source and the polarized light separator 16. The colored film 160 has a first coloring region for coloring the light from the light source to a first color and a second coloring region for coloring the light from the light source to a second color.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a display device, and more particularly, to a display device using a liquid crystal as a transmission optical axis variable unit. In particular, the present invention relates to a so-called transflective liquid crystal display device which functions as a transmissive liquid crystal display device when the light source is turned on and functions as a reflective liquid crystal display device when the light source is turned off. Also, a clock provided with this display device as a display unit,
The present invention relates to an electronic device such as an electronic organizer or a personal computer.

[0002]

2. Description of the Related Art Conventional TN (Twisted Nematic) liquid crystal and S
As shown in FIG. 26, a liquid crystal display device using a transmission polarization axis variable optical element 2605 such as a TN (Super-Twisted Nematic) liquid crystal which can change the polarization axis has two polarizing plates. Since the structure sandwiched between 2601 and 2606 was adopted, the efficiency of light utilization was poor, and especially when it was of a reflection type, dark display was caused.

[0003]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a display device using a variable transmission polarization axis optical element, which can provide a bright display.

Further, in the conventional transflective liquid crystal display device, since the Al reflector is formed thin or an opening is provided, the reflectivity at the time of reflective display is reduced. That is, the brightness at the time of reflective display is sacrificed by using a transflective type.

Therefore, another object of the present invention is to provide a light source on the back side of a reflection type liquid crystal display device, and perform not only reflection display by external light but also display by transmitted light from the light source on the back side. An object of the present invention is to provide a transmissive and bright reflective liquid crystal element.

Further, in the transflective liquid crystal display device, when external light enters the display device when the light source is turned on due to so-called positive / negative inversion, the display may be difficult to see.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a display device in which the display is not difficult to see even if the positive / negative inversion occurs.

[0008]

According to the present invention, there is provided a transmission polarization axis changing means for changing a transmission polarization axis, and a transmission polarization axis changing means disposed on both sides of the transmission polarization axis changing means with the transmission polarization axis changing means interposed therebetween. A display device, comprising: a first and a second polarization separation unit; and a light source disposed on a side opposite to the transmission polarization axis variable unit with respect to the second polarization separation unit, wherein the first polarization separation unit is provided. Means for converting a linearly polarized light component in a first predetermined direction out of light incident from a first side of the first polarization separation means to a second side opposite to the first side, the first predetermined direction. Transmitted as linearly polarized light in the first direction, and among the light incident from the first side of the first polarization separation means, a linearly polarized light component in a second direction different from the first direction is converted to the second side. In the first predetermined direction of light incident from the second side of the first polarization separation unit The linearly polarized light component first
Side as linearly polarized light in the first predetermined direction, and among the light incident from the second side of the first polarization separation means, the linearly polarized light component in the second direction is converted to the first polarized light. A polarization splitting unit that does not transmit the light to the light source side, wherein the second polarization splitting unit transmits a linear attenuating component in a third predetermined direction of the light incident from the transmission polarization axis changing unit side to the light source side. The linearly polarized light component in a fourth predetermined direction different from the third predetermined direction is reflected toward the transmission polarization axis variable unit, and the light incident from the light source side is transmitted through the transmission polarization axis variable unit. A polarization splitting unit that emits linearly polarized light in the third predetermined direction.

In the display device according to the present invention, for the light incident from outside the first polarization splitting means, the second polarization splitting means varies according to the state of the transmission polarization axis of the transmission polarization axis changing means. The first display state by the light reflected from the means and the second display state of the state in which the light transmitted through the second polarization separation means is absorbed by the light source are obtained. Display device. The first display state is a display state due to light reflected from the second polarization splitting means, so that a bright display is obtained.

[0010] Further, for light from the light source, a third display state by the light transmitted through the first polarization separation means and the first display state are determined according to the state of the transmission polarization axis of the transmission polarization axis changing means.
And a fourth display state in which light does not pass through the polarization separation means, and a transmission type display can be obtained.

[0011] Preferably, the second polarization splitting means is configured to output the third polarization light out of the light incident from the transmission polarization axis changing means side with respect to light in substantially the entire wavelength range of the visible light range.
Transmitting a linearly polarized light component in a predetermined direction to the light source side,
The linearly polarized light component in the fourth predetermined direction, which is different from the third predetermined direction, is reflected toward the transmission polarization axis variable unit, and is light in substantially the entire wavelength range of a visible light region, from the light source side. It is a polarization separating means capable of emitting linearly polarized light in the third predetermined direction to the transmitted polarization axis changing means side with respect to the incident light.

With this configuration, the first to fourth display states can be obtained for light in the entire wavelength range of the visible light region, and the first and third display states can be transparent or white. You can get the display.

[0013] The second polarization separating means may convert the linearly polarized light component in the third predetermined direction of the light incident from the transmission polarization axis changing means side into the third predetermined direction on the optical element side. It is a polarized light separating means for transmitting as a linearly polarized light in the direction. Preferably, the second polarized light separating means is a multilayer film in which a plurality of layers are laminated, and the refractive indices of the plurality of layers are between layers adjacent to each other, in a third predetermined direction. It is preferable that the polarization separation means be the same and be different in the fourth predetermined direction.

[0014] Preferably, the first polarized light separating means is a polarizing plate.

Preferably, the transmission polarization axis changing means is a liquid crystal panel, and more specifically, a TN liquid crystal panel, an STN liquid crystal panel, an F-STN liquid crystal panel, or an ECB liquid crystal panel. . This ST
The N liquid crystal panel is specifically, F-STN (Film compens
ated Super-Twisted Nematic) STN liquid crystal panels that use an optical anisotropic body for color compensation, such as liquid crystal panels, and actively use the birefringence of liquid crystals without using an optical anisotropic body for color compensation.
STN liquid crystal panel.

Preferably, the surface color of the light source is darkened to suppress the reflection on the surface of the light source. As a result, the light transmitted through the optical enclosure is reflected by the light source and returns again. The amount can be reduced, and a decrease in contrast can be suppressed.

Preferably, between the second polarization splitting means and the light source, the light from the second polarization splitting means is absorbed and the light from the light source is separated by the second polarization splitting means. It is characterized by further comprising a transmissible optical element on the means side.

By providing such an optical element, light incident from the outside of the first polarization splitting means can be changed according to the state of the transmission polarization axis of the transmission polarization axis changing means.
A first display state by light reflected from the second polarization separation unit and a second display state of a state in which light transmitted through the second polarization separation unit is absorbed by the light source and the optical element. Two display states are obtained, and a reflective display device is obtained. Then, in the second display state, not only the light source but also the optical element absorbs light, resulting in a darker display.

In addition, for the light from the light source, the third display state by the light transmitted through the first polarization separation means and the third display state are determined according to the state of the transmission polarization axis of the variable polarization axis. 1
And a fourth display state in which light does not pass through the polarization separation means, and a transmission type display can be obtained.

Preferably, the optical element is an optical element that absorbs light in a substantially entire wavelength range of a visible light region,
More preferably, it is good to be a black light absorber.

Further, the optical element may have an opening. By providing the opening in this manner, light from the light source can be transmitted through the opening to the second polarization separation unit.

In the reflection type display when external light is incident on the display device of the present invention, as described above,
A first display state by light reflected from the second polarization separation means, and a second display state by which light transmitted through the second polarization separation means is absorbed by the optical element. Is obtained. However, since the optical element is an optical element that absorbs light from the second polarization separation unit and transmits light from the light source to the second polarization separation unit, In the display state,
Depending on the structure of this optical element, not all light is absorbed by the optical element, but some light passes through the optical element and is reflected by a light source, etc. It may return to the axis variable means side and lower the contrast.

Therefore, preferably, when the optical element has a plurality of openings, light is transmitted through the optical element and the optical element is controlled by limiting the ratio of the opening to the optical element. The amount of light returning through the light source can be reduced, and a decrease in contrast can be suppressed. Preferably, the area ratio of the opening to the optical element is 5 to 30%.

Preferably, the distance between the optical element and the light source is set to be equal to or larger than the diameter of the opening, so that the amount of light transmitted through the optical element reflected by the light source and returned again is reduced. And a decrease in contrast can be suppressed.

Further, the optical element may be a light absorber in a gray semi-transmissive state. The optical element also absorbs light from the second polarization splitting means and converts light from the light source to the second polarization. The light can be transmitted to the separation means. that time,
It is preferable that the light absorber in the semi-transmissive state has a transmittance of 10% or more and 80% or less with respect to light in almost all visible wavelength ranges.
More preferably, the transmittance is 10% or more and 30% or less.

Preferably, the optical element is a polarizing plate, and the transmission axis of the second polarization separation does not coincide with the transmission axis of the optical element. With this configuration, it is possible to absorb the light from the transmission polarization axis changing unit and to transmit the light from the light source to the transmission polarization axis changing unit.

Preferably, the optical element is a light scatterer capable of changing the polarization state of light incident on the optical element and emitting the light from the optical element. With such an optical element, for light incident from the outside of the first polarization separation means, the light is transmitted from the second polarization separation means in accordance with the state of the transmission polarization axis of the transmission polarization axis variable means. The first display state by the reflected light and the second display state in which the light transmitted through the second polarization splitting means cannot be transmitted through the polarization splitter because the polarization state is eliminated by the scattering plate. Two display states are obtained, and a reflective display device is obtained. Then, in the second display state, not only the light source but also the optical element absorbs light, resulting in a darker display.

For the light from the light source, the third display state by the light transmitted through the first polarization splitting means and the first display state are determined according to the state of the transmission polarization axis of the transmission polarization axis changing means.
And a fourth display state in which light does not pass through the polarization separation means, and a transmission type display can be obtained.

Preferably, the apparatus further comprises means for condensing light from the light source toward the front of the display device.

Normally, when viewing a reflection type display using external light, the display is viewed at a position inclined at an angle from a normal to the front of the display device. If the display is viewed from the normal direction to the front of the display device, the external light incident on the display device is obstructed by the observer himself, so that the reflection type display by the external light becomes dark. On the other hand, when viewing the display by the transmitted light from the light source, since it is usually viewed from the normal direction to the front of the display device, means for condensing the light from the light source toward the front of the display device is used. By preparing
The display by the light transmitted from the light source can be brightened,
As a result, the transmissive display by the light from the light source is easily seen in the normal direction to the front of the display device.

Preferably, the apparatus further comprises a light diffusing means. With this configuration, external light is reflected in the first display state by light reflected by the second polarization separation unit, and light from a light source is transmitted by the first polarization separation unit.
Can be displayed in white.

The light source may include a cold cathode tube capable of emitting white light, and a light guide plate capable of emitting white light incident from the cold cathode tube to the second polarization separation means. Is used, as described above, for light from a light source,
Depending on the state of the transmission polarization axis of the transmission polarization axis changing unit, a third display state by light transmitted through the first polarization separation unit and a fourth display state in which light is not transmitted through the first polarization separation unit. Two display states, a display state and a display state, can be obtained, and the display can be of a transmissive type.
When the state of the transmission polarization axis of the transmission polarization axis changing unit is on, the third display state is obtained and white display is obtained, and when the state of the transmission polarization axis of the transmission polarization axis changing unit is off, the fourth display state is obtained. The display state is obtained, and the display becomes black. Then, at this time, when external light is incident from the first polarization separation unit side of the display device, the external light causes the second display to be performed when the state of the transmission polarization axis of the transmission polarization axis changing unit is on. The state is obtained and the display becomes black, and when the state of the transmission polarization axis of the transmission polarization axis changing means is off, the first display state is obtained and the display becomes white.

As a result, in either of the on and off cases, for example, when the display by the transmitted light from the light source is a white display, the reflection type black display by the external light is added, and the display becomes a gray display. Even when the display by transmitted light is a black display, a reflection-type white display by external light is added, and the display becomes gray again, so that a so-called positive / negative inversion phenomenon occurs, and the display becomes difficult to see.

Therefore, preferably, the light from the light source is emitted by using an LED capable of emitting light in a predetermined wavelength region to the second polarization separation means or an EL element capable of emitting light in a predetermined wavelength region. In the case of colored light, this colored color is displayed on a gray background, and transmission display by light from a light source becomes easy to see.

In the case where an LED is used as the light source, the light source includes a first LED capable of emitting light in a first predetermined wavelength range and a wavelength different from the first predetermined wavelength range. A second LED capable of emitting light in a second predetermined wavelength range, which is a range, preferably as a light source.
In the case of using an EL element, the light source includes a first EL element capable of emitting light in a third predetermined wavelength range, and the first EL element.
It is preferable to include a second EL element capable of emitting light in a fourth predetermined wavelength range that is different from the third predetermined wavelength range. And preferably, if the first and second LEDs or the first and second EL elements correspond to the respective character display sections, different display colors can be obtained in the respective character display sections. It is very useful because it gives you a wider range of choices.

When an LED is used as the light source, the LED can emit light in a predetermined wavelength range.
And a light guide plate capable of emitting the light of the predetermined wavelength region incident from the LED to the second polarization splitting means side. With this configuration, the light emitted from the LED can be once incident on the light guide slope, and then the light can be emitted from the light guide plate toward the second polarization maintaining means.
Since the position where the light is arranged can be determined relatively freely, the width of the design is widened, and the light emitted to the second polarization separation means side is uniform.

Further, the light guide plate includes the first LED.
A first light guide region from which light in the first predetermined wavelength range is incident, and emits light in the first predetermined wavelength range on the side of the second polarization separation means; and The light in the second predetermined wavelength range is incident from the LED, and
A second light guide region that emits light in the second predetermined wavelength range on the side of the polarization separation means, and between the first light guide region and the second light guide region. It is preferable to provide a light shielding means. By providing such a light shielding means, the first
Since the predetermined wavelength region and the second predetermined wavelength region do not mix with each other, color purity is increased.

[0038] Regarding the question of the light source and the second polarization splitting means, a coloring material capable of transmitting or reflecting light within a predetermined wavelength range and absorbing light having a wavelength outside the predetermined wavelength range. A layer may be provided. With this configuration, since the light from the light source is colored and enters the second polarization separation unit, the display of the colored color is performed on a gray background, and the transmission display by the light from the light source becomes easy to see. In this case, since the light from the light source is colored by the coloring layer, a white light source such as a cold cathode tube may be used as the light source. Of course, the above-mentioned LED or EL element may be used.

Further, the colored layer includes a first colored region capable of reflecting or transmitting light in a first predetermined wavelength range and a second predetermined wavelength different from the light in the first predetermined wavelength range. It is preferable that a second colored region capable of transmitting or reflecting light in a range is provided, and light having a wavelength outside the first or second predetermined wavelength range can be absorbed. And preferably, if the first and second coloring regions correspond to each character display portion,
Since different display colors can be obtained in each character display,
The range of design choices expands.

Further, between the colored layer and the light source,
Transmitting the light from the light source to the colored layer side;
It is more preferable to further include a semi-transmissive reflection plate capable of reflecting light that has entered the coloring layer from the side of the polarized light separating means and transmitted through the coloring layer and emits the light toward the coloring layer. Then, as the transflective plate, a specular reflector provided with an opening can be used. With this configuration, for light incident from outside the first polarization separation unit, the light is reflected from the second polarization separation unit according to the state of the transmission polarization axis of the transmission polarization axis variable unit. A first display state by light, and a second display state by light transmitted through the second polarization separation unit, reflected by the colored layer, and once transmitted through the colored layer, and then reflected by the reflector. Are obtained, and a reflective display device is obtained. In the second display state, the degree of coloring is increased by the presence of the reflection plate.

Further, an electronic apparatus according to the present invention includes the above-described display device as a display unit.

[0042]

Embodiments of the present invention will now be described with reference to the drawings.

[0043]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment <Basic Structure> FIG. 1 is a sectional view of a display device according to a first embodiment of the present invention, and FIG. 2 is a sectional view of the first embodiment of the present invention. FIG. 4 is a schematic cross-sectional view for explaining a display principle of the display device.

The display device 100 can perform a reflection type display utilizing the reflection of external light in a place where external light exists, and a transmission type display using light from a light source even in a place where external light does not exist. This is a reflective display device having a so-called semi-transmissive function capable of displaying.

First, the structure of the display device of the present embodiment will be described with reference to FIG. In this display device 100,
The TN liquid crystal panel 10 is used as a transmission polarization axis variable optical element. In the TN liquid crystal panel 10, a TN liquid crystal 13 is supported between two glass plates 11 and 12,
A plurality of character display units (not shown) are provided to enable character display. A polarizing plate 14 is provided above the TN liquid crystal panel 10. On the lower side of the TN element panel 10, a light scatterer 15, a polarization separator 16, and a light source 17 are provided in this order. Further, a T-driver with a driver IC for driving the TN liquid crystal 10 is mounted.
An AB board (not shown) is connected to the TN liquid crystal panel 10 to constitute a display device.

<Polarization Separator> Next, the polarization separator used in the present embodiment will be described with reference to FIGS. FIG. 4 is a schematic configuration diagram of the polarization separator 16 used in the present embodiment.
FIG. 4 is a diagram for explaining the operation of the polarization separator 16 shown in FIG. The polarization splitter 16 has two different layers 4
1 (A layer) and 42 (B layer) have a structure in which a plurality of layers are alternately laminated. In this polarization separator 16, A
Although the refractive index (n _AX ) of the layer 41 in the X-axis direction and the refractive index (n _BX ) of the B layer 42 in the X-axis direction are different, the refractive index (n _AY ) of the A layer 41 in the Y-axis direction and the B layer 42 is substantially equal to the refractive index (n _BY ) in the Y-axis direction. The linearly polarized light in the Y-axis direction among the light incident on the polarization separator 16 passes through the polarization separator 16 because the refractive indices of the A layer 41 and the B layer 42 in the polarization separator 16 are substantially equal. . On the other hand, the thickness of the A layer 41 of the polarization separator 16 in the Z-axis direction is t _A , B
When the thickness of the layer 41 and _{t B,} of the light incident on the _{t A · n AX + t B} · n BX = λ / 2 (1) and so as the polarization separator 16 a light of the wavelength lambda by The linearly polarized light in the X-axis direction is reflected by the polarization separator 16. And A layer 4
1, the thickness of the B layer 42 in the Z-axis direction and the thickness of the B layer 42 in the Z-axis direction are variously changed. Reflects linearly polarized light in the X-axis direction.

The A layer 41 of the polarization separator 16 is, for example, polyethylene naphthalate (PEN; polyethylene).
A layer obtained by stretching napthalate) is used, and the B layer 42 is provided with a copolyester of napthalene dica (coPEN) of naphthalene dicarbonic acid and terephthalic acid.
rboxylic acid and terephthallic or isothalic aci
d) can be used.

Of course, the polarization separator 16 used in the present invention
The material is not limited to this, and the material can be appropriately selected. In addition, such a polarization separator is disclosed in an international application (international application number: WO / 95/2781).
9 and WO95 / 17692), reflective polrize
The details are disclosed as r.

In the present embodiment, the above-mentioned polarization separator is used. In addition to this polarization separator, for example, a cholesteric liquid crystal layer sandwiched between λ / 4 plates, the Brewster angle is used. Thing (SID 92DIGEST
(Pages 427 to 429), those using holograms, etc., have the same functions as the above-described polarization splitters, and they may be used in the display device of the present embodiment.

<Display Principle> The principle of display by the display device 100 will now be described with reference to FIG. 2 using the right half of the display device 100 as a voltage application portion and the left half as a non-voltage application portion. First, a reflection type display when external light is incident on the display device 100 will be described.

In the left non-voltage application section, when external light enters the display device 100, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the plane of the drawing.
The polarization direction is twisted by 90 ° by the N liquid crystal 13 to become linearly polarized light in a direction perpendicular to the paper surface, and is reflected by the polarization separator 16 as linearly polarized light in the direction perpendicular to the paper surface, and the polarization direction is 90 ° by the TN liquid crystal 13. It is twisted and becomes linearly polarized light in a direction parallel to the paper surface, and is emitted from the polarizing plate 14 as linearly polarized light in a direction parallel to the paper surface. As described above, when no voltage is applied, the incident external light is reflected instead of being absorbed by the polarization separator 16, so that a bright reflective display is obtained. Since the light scatterer 15 is provided between the polarization separator 16 and the TN liquid crystal panel 10, the polarization separator 16
The light reflected from the mirror becomes white from a mirror-like state.

In the right-side application section, when external light is incident on the display device 100, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the paper surface.
The liquid crystal 13 passes through the liquid crystal 13 without changing the polarization direction, and is polarized.
Also transmits without changing the polarization direction and reaches the light source 17. Most of the light reaching the light source 17 passes through the light source or is absorbed by the light source, so that a dark display is obtained.

As described above, in the reflection type display when the external light is incident on the display device 100, the light reflected by the polarization separator 16 is applied to the light scatterer 1 in the non-voltage applying section.
5, a bright display is obtained, and most of the light transmitted through the polarization separator 16 is transmitted through the light source 17 in the voltage application unit.
Alternatively, the display is dark because the light is absorbed by the light source 17.

When no voltage is applied, the external light incident on the display device 100 is reflected by the polarization separator 16 without being absorbed, so that a bright display is obtained.

Next, a transmission type display using light from the light source 17 will be described.

In the left non-voltage application section, the light from the light source 17 enters the polarization separator 16 and is converted into linearly polarized light in a direction parallel to the paper by the polarization separator 16.
The polarization direction is twisted by 90 ° by the liquid crystal 13 to be linearly polarized light in a direction perpendicular to the paper surface, and is absorbed by the polarizing plate 14 to provide a dark display.

In the voltage application section on the right side, the light from the light source 17 enters the polarization separator 16, is converted into linearly polarized light in a direction parallel to the paper by the polarization separator 16, becomes scattered light by the light scatterer 15, The TN liquid crystal 13 is transmitted without changing the polarization direction, and the TN liquid crystal 13 is also transmitted, thereby providing a bright display.

As described above, in the transmission type display using the light from the light source 17, the light from the light source 17 is absorbed by the polarizing plate 14 in the voltage non-applied portion, resulting in a dark display. A bright display is obtained through the plate 14.

Therefore, the display device 100 can perform bright reflection type display utilizing the reflection of external light in a place where external light exists, and can display light from the light source 17 even in a place where there is no external light. , A reflection type display device having a so-called semi-transmission type function.

<Scattering Plate> As the scattering plate used in the display device of this embodiment, a scattering plate capable of emitting incident light without minimizing the polarization state is used. In addition, since this scattering plate has a function to scatter and cloud light emitted from the scattering plate, a display device having a cloudy display (white display) can be obtained. On the other hand, if the scattering plate 15 is removed from the configuration, the display device can display a glossy color. Therefore, the scattering plate may be removed according to the use of the display device.

<Light Source> FIGS. 5 to 9 show the display device of the present embodiment when various light sources are used. In this embodiment, any of the light sources shown in FIGS. 5 to 8 can be used.

The light source used in the display device shown in FIG. 5 includes a cold cathode tube 50 as a light source and a light guide plate 51. The light guide plate 51 has a light absorbing function when the cold cathode tube 50 is turned off.

When the light source shown in FIG. 5 is used in the display device of the present embodiment, a display when external light containing visible wavelength components of a plurality of colors is incident, that is, for a reflective display, the voltage is applied to the black portion at the voltage application section. The display becomes a white display in the portion where no voltage is applied.
On the other hand, in the transmission type display using the light from the light source, the light emission color of the cold-cathode tube is displayed in the voltage application unit, that is, white display, and the black display is performed in the non-voltage application unit.

The light source used in the display device shown in FIG. 6 employs an LED 60 that emits light of a red wavelength as a light source, and further includes a light guide plate 61. When the light source shown in FIG. 6 is used in the display device of this embodiment,
Regarding the reflection type display, black display is performed in the voltage application section and white display is performed in the non-voltage application section. On the other hand, in the transmission type display using the light from the light source, the color of the light emitted from the LED 60 is displayed in the voltage application unit, that is, the display is red, and in the non-voltage application unit, the display is black.

By the way, when the light source shown in FIG. 5 is used, as described above, the light from the light source 17 has a dark display in the non-voltage-applied portion and a bright display in the voltage-applied portion. Can be obtained, and can be a transmission type display. In this case, when external light enters from the front side of the display device, the external light causes a bright display in a group where no voltage is applied, and Indicates a bright black display. As a result, in both the voltage non-applying section and the voltage applying section, for example, when the display by the transmitted light from the light source 17 is a bright display, the reflection type dark display by the external light is added, and the display becomes gray. Even in the case where the display by the transmitted light from 17 is a dark display, the reflection type bright display by the external light is added, and the display becomes gray, so that a so-called positive-negative inversion phenomenon occurs, and the display becomes difficult to see. is there.

When the light source is turned on using the light source shown in FIG. 6 when external light is incident, light emitted from the LED can be seen in the voltage application portion, so that the display becomes grayish red, and polarization separation occurs in the voltage non-application portion. Since the external light reflected by the device 16 can be seen, the display becomes gray, making it much easier to see than a simple black and white display.

Although the LED 60 that emits light of a red wavelength is used in FIG. 6, an LED that emits light of a wavelength other than red may be used.

The light source used in the display device shown in FIG. 7 is an EL element 70 that emits light of a green wavelength as a light source.
Is adopted. When the light source shown in FIG. 7 is used in the display device of the present embodiment, black display is performed in the voltage application section and white display is performed in the non-voltage application section in the reflective display. On the other hand, in the transmission type display using light from the light source, the color of the light emitted from the EL element 70 is displayed in the voltage application section, that is, green display is performed, and in the non-voltage application section, black display is performed. This FIG.
When the light source is turned on at the time of external light incidence using the light source shown in (1), light emitted from the EL element 70 can be seen in the voltage application part, so that the display becomes grayish green display, and in the voltage non-application part, the light is reflected by the polarization separator. Since external light is visible, the display becomes gray. FIG. 7 shows an EL that emits light of a line color wavelength.
Although the element 70 is used, an EL element that emits light of a wavelength other than green may be used.

The light source used in the display device shown in FIG. 8 includes an LED 81 that emits light of red wavelength and an LED 82 that emits light of blue wavelength as light sources.
It is located on the side. The light guide plate is partitioned by a reflector 84 for each region corresponding to each LED so that the light of each wavelength emitted from the light guide plate is not mixed. Further, each LED is arranged such that its emitted light corresponds to a plurality of character display portions 85 and 86 formed on a liquid crystal panel. When the light source shown in FIG. 8 is used in the display device of the present embodiment, black display is performed in the voltage application section and white display is performed in the non-voltage application section for the reflective display. on the other hand,
For the transmission type display using light from the light source, in the voltage application section, each character display section has a corresponding LED.
The display of the color of the emitted light from, that is, red or blue display,
Black display is performed in the portion where no voltage is applied. When the light source is turned on using the light source shown in FIG. 8 when external light is incident, the emitted light from each LED can be seen in the voltage application unit, so that each character display unit becomes grayish red or blue display, and no voltage is applied. In the additional part, the external light reflected by the polarization splitter is visible, so that the display becomes gray. In FIG. 8, an LED that emits red wavelength light and an LED that emits blue wavelength light
However, it is needless to say that an LED that emits light of a wavelength other than these colors may be used, and a combination thereof can be appropriately selected depending on the application.

The light source used in the display device shown in FIG. 9 is a plurality of LEDs which emit light of a red wavelength as a light source.
91 and a plurality of LEDs 92 for emitting light of a blue wavelength
Are arranged as an aggregate for each color. Note that FIG.
No light guide plate is provided for the light source in the above. Furthermore, each LE
The D group is arranged so that the emitted light corresponds to a plurality of character display sections 93 and 94 formed on the liquid crystal panel. When the light source shown in FIG. 9 is used in the display device of the present embodiment, black display is performed in the voltage application section and white display is performed in the non-voltage application section in the reflective display. On the other hand, in the transmission type display using light from the light source, in the voltage application unit, each character display unit displays the color of light emitted from each corresponding LED group, that is, in red or blue display, and in the non-voltage application unit, it displays black. Display. When the light source is turned on at the time of external light incidence using the light source shown in FIG.
Since the light emitted from the ED group is visible, the display becomes grayish red or blue for each character display part, and the gray part is displayed in the part where no voltage is applied because external light reflected by the polarization separator is visible. In FIG. 9, an LED 91 that emits light of a red wavelength and an LED 9 that emits light of a blue wavelength
Although LED 2 was used, it is needless to say that an LED that emits light having a wavelength other than these colors may be used, and a combination thereof may be appropriately selected.

(Second Embodiment) FIG. 10 is a sectional view of a display device according to a second embodiment of the present invention.
FIG. 1 is a schematic cross-sectional view for explaining a display principle of a display device according to a second embodiment of the present invention.

This display device 1000 can perform a reflection type display utilizing reflection of external light in a place where external light exists, and a transmission type display using light from a light source even in a place where external light does not exist. This is a reflective display device having a so-called semi-transmissive function capable of displaying.

<Basic Structure> First, the structure of the display device of the present embodiment will be described with reference to FIG. This display device 10
In OO, a TN liquid crystal panel 10 is used as a variable transmission polarization axis optical element. In the TN liquid crystal panel 10, a TN liquid crystal 13 is sandwiched between two glass plates 11 and 12, and a plurality of character display units (not shown) are provided so that characters can be displayed. TN
A polarizing plate 14 is provided above the liquid crystal panel 10. On the lower side of the TN element panel 10, a light scatterer 15, a polarization separator 101, a light absorber 102, and a light source 17 are provided in this order. The light absorber 102 is black, and a plurality of openings 103 are provided at a predetermined area density. Further, a TAB board (not shown) on which a driver IC for driving the TN liquid crystal 13 is mounted is connected to the TN liquid crystal panel 10 to constitute a display device.

<Polarization Separator> The polarization separator 101 is (1 /
4) A λ plate 104 and a cholesteric liquid crystal layer 105 are provided. The cholesteric liquid crystal 105 has the property of reflecting light having the same wavelength as the pitch of the liquid crystal, circularly polarized light in the same rotation direction as the liquid crystal, and transmitting other light. Therefore, for example, the cholesteric liquid crystal layer 105
If a cholesteric liquid crystal having a pitch of 5000 Å and rotating counterclockwise is used, an element is obtained that reflects left circularly polarized light having a wavelength of 5000 Å and transmits right circularly polarized light and left circularly polarized light having other wavelengths. Furthermore, by using a left-handed cholesteric liquid crystal and changing its pitch within the cholesteric liquid crystal over the entire visible light wavelength range, it reflects left circularly polarized light and transmits right circularly polarized light not only for a single color but also for all bright colored light. An element is obtained. In the present embodiment, a cholesteric liquid crystal that is rotated left is used as the cholesteric liquid crystal layer 105, and its pitch is changed in the cholesteric liquid crystal over the entire visible light wavelength range.

The polarization separator 10 in which such a cholesteric liquid crystal layer 105 and the (１ ／) λ plate 104 are combined.
In the case of No. 1, a predetermined (No. 1)
When linearly polarized light in the direction of 1 enters, the (1/4) λ plate 104
Cholesteric liquid crystal layer 105
And is again emitted as linearly polarized light in a predetermined first direction by the (1/4) λ plate 104. When linearly polarized light in a second direction orthogonal to the first direction enters, (1
/ 4) Right circularly polarized light is transmitted by the λ plate 104 and transmitted through the cholesteric liquid crystal layer 105. Further, for light incident from below the cholesteric liquid crystal layer 105, (1/1 /
4) The linearly polarized light in the second direction is emitted above the λ plate 104.

As described above, the cholesteric liquid crystal layer 105
Polarizer 1 Combined with (1/4) λ Plate 104
01 transmits a linearly polarized light component in a predetermined second direction of light incident from the (1/4) λ plate 104 side, and transmits a predetermined second
Reflect a linearly polarized light component in a first direction orthogonal to the direction of
This is a polarization separation unit that can emit linearly polarized light in the second direction to the (1/4) λ plate 104 side with respect to light incident from the cholesteric liquid crystal layer 105 side. The cholesteric liquid crystal layer 105 is used as a polarization separator having this function.
Polarizer 1 Combined with (1/4) λ Plate 104
01, using a film in which a multi-layer film is laminated (US Pat. No. 4,974,219), and using a Brewster angle to separate reflected polarized light and transmitted polarized light (SI
D 92DIGEST pp. 427-429),
The one using a hologram, the polarization separator described in the first embodiment described above with reference to FIGS. 3 and 4,
That is, an international application published internationally (international application number: WO
95/27819 and WO 95/17692).

<Display Principle> Next, this display device 1000 will be described.
The display by the display device 1000 will be described with the right half as a voltage application unit and the left half as a no voltage application unit.

First, the reflection type display when external light is incident on the display device 1000 will be described.

In the left non-voltage application section, when external light is incident on the display device 1000, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the sheet of paper.
The polarization direction is twisted by 90 ° by the TN liquid crystal 13 to be linearly polarized light in a direction perpendicular to the paper surface, left circularly polarized by the (1/4) λ plate 104, reflected by the cholesteric liquid crystal layer 105, and again (1/4) incident on the λ plate 104,
4) Linear polarization in the direction perpendicular to the plane of the paper by the λ plate 104, the polarization direction is twisted by 90 ° by the TN liquid crystal 13 to become linear polarization in the direction parallel to the plane of the paper, and linear polarization in the direction parallel to the plane of the paper from the polarization plate 14. And emitted. As described above, when no voltage is applied, the incident external light is reflected instead of being absorbed by the polarization separator 101, so that a bright reflective display is obtained. Since the light scatterer 15 is provided between the (1/4) λ plate 104 and the TN liquid crystal panel 10, the reflected light from the polarization splitter 101 changes from a mirror surface to a bright color.

In the right voltage application section, when external light enters the display device 1000, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the paper surface.
N is transmitted through the liquid crystal 13 without changing the polarization direction, and
The light becomes right-handed circularly polarized light by the plate 104 and passes through the cholesteric liquid crystal layer 105. The right-handed circularly polarized light transmitted through the cholesteric liquid crystal layer 105 is absorbed by the black light absorber 102 to provide a dark display.

As described above, external light is applied to the liquid crystal display device 1000.
In the reflection type display when light is incident on the light, the light reflected by the polarization splitter 101 passes through the light scatterer 15 in the voltage non-applying section to provide a bright display. Light absorber 1 whose transmitted light is black
02, the display becomes dark.

When no voltage is applied, external light incident on the display device 1000 is reflected by the polarization separator 101 without being absorbed, so that a bright display is obtained.

Next, a transmission type display using light from the light source 17 will be described.

In the left non-voltage application section, the light source 17
Light from the aperture 1 provided in the black light absorber 102
03, the light enters the cholesteric liquid crystal layer 105 of the polarization separator 101, only right circularly polarized light passes through the cholesteric liquid crystal layer 105, and is converted into linearly polarized light in a direction parallel to the paper by the (1/4) λ plate 104. Then, the TN liquid crystal 13
As a result, the polarization direction is twisted by 90 ° and becomes linearly polarized light in a direction perpendicular to the paper surface, and is absorbed by the polarizing plate 14 to provide a dark display.

In the voltage application section on the right side, the light from the light source 17 passes through the opening 10 provided in the black light absorber 102.
3, the light is incident on the polarization separator 101 and the cholesteric liquid crystal layer 105, and only right-circularly polarized light is transmitted through the cholesteric liquid crystal layer 105, and is converted into linearly polarized light in a direction parallel to the paper by the (1/4) λ plate 104. The light passes through the light scatterer 15, then passes through the TN liquid crystal 13 without changing the polarization direction, and also passes through the polarizing plate 14 to provide a bright display.

As described above, in the transmissive display using the light from the light source 17, the light from the light source 17 is absorbed by the polarizing sheet 14 in the non-voltage-applied portion, resulting in a dark display. A bright display is obtained through the slope 14.

Therefore, the display device 1000 can perform bright reflection type display utilizing the reflection of external light in a place where external light exists, and can display light from the light source 17 even in a place where there is no external light. , A reflection type display device having a so-called semi-transmission type function.

<Scattering Plate> As the scattering plate 15 used in the display device according to the present embodiment, a scattering plate capable of emitting incident light without minimizing the polarization state is used.
Since the scattering plate 15 has a function of scattering and scattering light emitted from the scattering plate, a display device having a cloudy display (white display) can be obtained. On the other hand, if the scattering plate 15 is removed from the configuration, the display device can display a glossy color. Therefore, the scattering plate may be removed according to the use of the display device.

<Light Absorber> In the present embodiment, in the reflection type display when external light is incident on the display device 1000, as described above, a bright display by the light reflected from the polarization splitter 101 is performed. And a dark display state in which the light transmitted through the polarization separator 101 is absorbed by the light absorber 102. However, the light absorber 102 is a black light absorber and the polarization separator 101.
And has a plurality of openings 103, and light can be transmitted through the openings 103. Therefore, in the dark display state, the light absorber 103
Not all light is absorbed by the light absorbing member 102, but a certain amount of light passes through the light absorbing member 102 through the opening 103, is reflected by the light source 17 or the like, and is also reflected by the light absorbing member 102 through the opening 103. , And returns to the TN liquid crystal panel 10 side, thereby lowering the contrast.

Therefore, preferably, by limiting the ratio of the opening 103 to the light absorber 102, light is transmitted through the light absorber 102 through the opening 103 and reflected by the light source 17 or the like. The opening 103 of the light absorber 102
, The amount of light returning through the light emitting element can be reduced, and a decrease in contrast can be suppressed.

In this embodiment, the light absorber 102
Although a black light absorber having a plurality of openings 103 was used, a gray semi-transmitting light absorber can also be used, and also absorbs light from the polarization separator 101 side, Light from the light source 17 can be transmitted to the polarization separator 101 side. In this case, since the light absorber is in a gray semi-transmissive state, it is not necessary to provide an opening. As the light absorber in the gray semi-transmissive state, a light diffusion film D202 (Tsujimoto Electric Works) or the like can be used.

Alternatively, a black light absorber having a plurality of openings 103 was used as the light absorber 102, but instead of the light absorber 102, a polarizing plate whose absorption axis was shifted from the polarization separator 101 was used. Can also be used. With this configuration, the light from the TN liquid crystal panel 10 can be absorbed by the polarization separator 101 and the polarizing plate whose absorption axis is shifted from the polarization separator 101, and the light from the light source 17 can be transmitted to the TN liquid crystal panel 10 side. .

<Light Source> For the display device according to the present embodiment, the various light sources described with reference to FIGS. 5 to 9 and described in the first embodiment can be used. Since the operation and effect are the same as those of the first embodiment, the description is omitted here.

(Third Embodiment) <Basic Structure> FIG. 12 is a schematic sectional view illustrating a display device according to a third embodiment of the present invention.

In the above-described second embodiment,
(偏光) The polarization separator 101 including the λ plate 104 and the cholesteric liquid crystal layer 105 was used. In the present embodiment, instead of the polarization separator 101, (1/4)
4) The λ plate 104 and the cholesteric liquid crystal layer 105
4) The second embodiment is different from the second embodiment in that a polarization separator 121 having a λ plate 120 is used, but the other points are the same.

<Polarization Separator> In the polarization separator 121 in which the (104) λ plates 104 and 120 are provided on both sides of such a cholesteric liquid crystal layer 105, the (４) λ slope 1
When linearly polarized light in a predetermined first direction is incident from the side of the ０４04, it becomes left circularly polarized light by the (（) λ plate 104, is reflected by the cholesteric liquid crystal layer 105, and is
4 again emits linearly polarized light in a predetermined first direction. When linearly polarized light in the second direction orthogonal to the first direction enters, the light becomes right-handed circularly polarized light by the (1/4) λ plate 104, passes through the cholesteric liquid crystal layer 105, and becomes (1).
/ 4) The light is again converted into linearly polarized light in the second direction by the λ plate 120. In addition, for light incident from below the (1/4) λ plate 146, linearly polarized light in the second direction is emitted above the (1/4) λ plate 104.

As described above, the cholesteric liquid crystal layer 105
And the (１２１) λ plates 104 and 120 combine with each other, the polarization separator 121 converts the linearly polarized light component in a predetermined second direction in the light incident from the (１ ／) λ plate 104 side into the second direction. And transmits a linearly polarized light component in a first direction orthogonal to a predetermined second direction.
This is a polarization separation unit capable of emitting linearly polarized light in the second direction to the (1/4) λ plate 104 side with respect to light incident from the 20 side. In addition, as the polarization separation means having this function,
The cholesteric liquid crystal layer 105 and the (1/4) λ plate 10
In addition to the polarization separator 121 combining the elements 4 and 120,
Utilizing a multilayer film (USP4,
974, 219), which separates reflected polarized light and transmitted polarized light using the Brewster's angle (SID 92D).
IGEST, pp. 427 to 429), those using holograms, the polarization separator described in the first embodiment with reference to FIGS. 3 and 4, that is, an international application (international application number) : WO 95/27819 and WO / 17692), which are disclosed as reflective polrizers.

<Display Principle> Next, this display device 1200 will be described.
The display on the display device 1200 will be described with the right half as a voltage application unit and the left half as a no voltage application unit.

First, a reflection type display when external light is incident on the display device 1200 will be described.

The function of the voltage non-applying section on the left side is the same as the function of the voltage non-applying section of the first embodiment. That is, when external light is incident on the display device 1200, the external light is converted into linearly polarized light in a direction parallel to the plane of the paper by the polarizing plate 14, and then the polarization direction is twisted by 90 ° by the TN liquid crystal 13 so that the direction perpendicular to the plane of the paper is obtained. And becomes (偏光)
The left-handed circularly polarized light by the λ-sheet 104 is reflected by the cholesteric liquid crystal layer 105 and again incident on the (1/4) λ-plate 104, and becomes the linearly-polarized light in the direction perpendicular to the paper surface by the (１ ／) λ-plate 104 Polarization direction is 90 by TN liquid crystal 13
It is twisted into linearly polarized light in a direction parallel to the paper surface, and is emitted from the polarizing sheet 14 as linearly polarized light in a direction parallel to the paper surface.
As described above, when no voltage is applied, the incident external light is reflected instead of being absorbed by the polarization separator 121, so that a bright reflective display is obtained. Note that (1 /
4) Since the light scatterer 15 is provided between the λ sheet 104 and the TN liquid crystal panel 10, the reflected light from the polarization separator 121 changes from a mirror state to a white state.

In the voltage application section on the right side, when external light enters the display device 1200, the external light is converted into linearly polarized light in a direction parallel to the plane of the drawing by the polarizing sheet 14, and thereafter, T
N is transmitted through the liquid crystal 13 without changing the polarization direction, and
The right circularly polarized light that has been converted to right circularly polarized light by the plate 104, transmitted through the cholesteric liquid crystal layer 105, and transmitted through the cholesteric liquid crystal layer 105 becomes linearly polarized light in a direction parallel to the paper surface by the (1/4) λ plate 120, and then black. And the display becomes dark.

As described above, with respect to the reflection type display when external light is incident on the display device 1200, a bright display is obtained by being reflected by the polarization separator 121 in the voltage non-applying section, and the polarization separation in the voltage applying section. The light that has passed through the container 121 is absorbed by the black light absorber 102 to provide a dark display.

When no voltage is applied, the external light incident on the display device 1200 is reflected without being absorbed by the polarization separator 121, so that a bright display is obtained.

Next, a transmission type display using light from the light source 17 will be described.

In the left non-voltage application section, the light source 17
Light from the aperture 1 provided in the black light absorber 102
03, the (１ ／) λ plate 120 of the polarization separator 121
Incident on the cholesteric liquid crystal layer 105 after passing through the (1/4) λ plate 120,
5 transmits right circularly polarized light and reflects left circularly polarized light. The transmitted circularly polarized light is converted into linearly polarized light in a direction parallel to the plane of the paper by the (1/4) λ plate 104, and then the polarization direction is twisted by 90 ° by the TN liquid crystal 13 to become linearly polarized light in a direction perpendicular to the plane of the paper. 14 to provide a dark display.

In the voltage application section on the right side, the light from the light source 17 passes through the opening 103 provided in the black light absorber 102.
Of the light that has entered the (１ ／) λ plate 120 of the polarization separator 121 via the, and then only the right-handed circularly polarized light of the light that has entered the cholesteric liquid crystal layer 105 is transmitted. And becomes linearly polarized light in a direction parallel to
After that, the light passes through the TN liquid crystal 13 without changing the polarization direction, and also passes through the polarizing plate 14 to provide a bright display.

As described above, in the transmissive display using the light from the light source 17, the light from the light source 17 is absorbed by the polarizing sheet 14 in the non-voltage-applied portion, resulting in a dark display. A bright display is obtained through the plate 14.

Therefore, the display device 1200 can perform bright reflection type display utilizing the reflection of external light in a place where external light exists, and can display light from the light source 17 even in a place where there is no external light. , A reflection type display device having a so-called semi-transmission type function.

<Scattering Plate> As the scattering plate used in the display device of the present embodiment, a scattering plate capable of emitting incident light without minimizing the polarization state is used. In addition, since this scattering plate has a function to scatter and cloud light emitted from the scattering plate, a display device having a cloudy display (white display) can be obtained. On the other hand, if the scattering plate 15 is removed from the configuration, the display device can display a glossy color. Therefore, the scattering plate may be removed according to the use of the display device.

<Light Absorber> The light absorber used in the present embodiment can be the same as that used in the second embodiment. Also, by limiting the ratio of the opening 103 to the light absorber 102, a decrease in contrast can be suppressed as in the second embodiment. Of course, similarly to the second embodiment, a semi-transmissive light absorber or a polarizing plate whose absorption axis is shifted from the polarization separator 121 can be used.

<Light Source> The various light sources described in FIGS. 5 to 9 and the first embodiment can be used for the display device in the present embodiment. Since the operation and effect are the same as those of the first embodiment, the description is omitted here.

(Fourth Embodiment) <Basic Structure> FIG. 13 is a schematic sectional view illustrating a display device according to a fourth embodiment of the present invention.

In the second embodiment described above,
In the third embodiment, a (1/4) λ plate 104 cholesteric liquid crystal layer 105 (1/4) is used in the third embodiment using a polarization separator 101 including a (1/4) λ plate 104 and a cholesteric liquid crystal layer 105. Polarization separator 12 having λ plate 120
However, in the present embodiment, instead of these polarization separators 101 and 121, the polarization separator described in the first embodiment with reference to FIG. 3 and FIG. Published international application (international application number: WO
95/27819 and WO 95/17692) is that the polarization separator 16 is used as the polarization separator 16.
2. Although different from the third and third embodiments, the other points are the same as those of the second embodiment and the third embodiment.

<Polarization Separator> In this embodiment, the same one as described in the first embodiment with reference to FIGS. 3 and 4 is used. Here, the detailed description is omitted. Of course, in addition to the polarization separator, there are, for example, a cholesteric liquid crystal layer sandwiched between λ / 4 plates, a device using Brewster's angle (SID 92DIGEST pages 427 to 429), a device using a hologram, and the like. It has the same function as the above-described polarization separator, and may be used for the display device of the present embodiment.

<Display Principle> Next, the display device 1300
The display by the display device 11300 will be described with the right half as a voltage application unit and the left half as a no voltage application unit.

First, a reflection type display when external light is incident on the display device 1300 will be described.

In the left non-voltage application section, when external light is incident on the display device 1300, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the sheet of paper.
The polarization direction is twisted by 90 ° by the TN liquid crystal 13 to become linearly polarized light in a direction perpendicular to the paper surface, and is reflected by the polarization separator 16 as linearly polarized light in a direction perpendicular to the paper surface, and the TN liquid crystal 13
As a result, the polarization direction is twisted by 90 ° to become linearly polarized light in a direction parallel to the paper surface, and is emitted from the polarizing plate 14 as linearly polarized light in a direction parallel to the paper surface. As described above, when no voltage is applied, the incident external light is reflected instead of being absorbed by the polarization separator 16, so that a bright reflective display is obtained. Since the light scatterer 15 is provided between the polarization separator 16 and the TN liquid crystal panel 10, the polarization separator 1
The reflected light from 6 changes from a mirror surface to a bright color.

In the voltage application section on the right side, when external light enters the display device 1300, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the sheet of paper.
The N liquid crystal 13 is transmitted without changing the polarization direction,
6 also transmits without changing the polarization direction, and is thereafter absorbed by the black light absorber 102 to provide a dark display.

As described above, in the reflection type display when the external light is incident on the display device 1300, the light reflected by the polarization separator 16 is applied to the light scatterer 1 in the no-voltage application section.
5 and a bright display is obtained, and in the voltage application section, the light transmitted through the polarization separator 16 is absorbed by the black light absorber 102 to provide a dark display.

When no voltage is applied, external light incident on the display device 1300 is reflected by the polarization separator 16 without being absorbed, so that a bright display is obtained.

Next, a transmission type display using light from the light source 17 will be described.

In the left non-voltage application section, the light source 17
Light from the aperture 1 provided in the black light absorber 102
03 and enters the polarization separator 16,
Is converted into linearly polarized light in a direction parallel to the paper,
The polarization direction is twisted by 90 ° by the TN liquid crystal 13 to be linearly polarized light in a direction perpendicular to the paper surface, and is absorbed by the polarizing plate 14 to provide a dark display.

In the voltage application section on the right side, the light from the light source 17 passes through the opening 10 provided in the black light absorber 102.
3, the light enters the polarization separator 16 and is converted into linearly polarized light in a direction parallel to the paper by the polarization separator 16 so that the light scatterer 1
5, the TN liquid crystal 10 transmits scattered light without changing the polarization direction of the TN liquid crystal 10, and also transmits the polarizing plate 14 to provide a bright display.

As described above, in the transmission type display using the light from the light source 17, the light from the light source 17 is absorbed by the polarizing plate 14 in the voltage non-applied portion, resulting in a dark display. A bright display is obtained through the plate 14.

Therefore, the display device 1300 can perform bright reflection type display utilizing the reflection of external light in a place where external light exists, and can display the light from the light source 17 even in a place where there is no external light. , A reflection type display device having a so-called semi-transmission type function.

<Scattering Plate> As the scattering plate used in the display device of this embodiment, a scattering plate capable of emitting incident light without minimizing the polarization state is used. In addition, since this scattering plate has a function to scatter and cloud light emitted from the scattering plate, a display device having a cloudy display (white display) can be obtained. On the other hand, when the scattering plate 5 is removed from the configuration, a display device that can display a glossy color is obtained. Therefore, the scattering plate may be removed according to the use of the display device.

<Light Absorber> The same light absorber as that used in the second embodiment can be used for the present embodiment. Also, by limiting the ratio of the opening 103 to the light absorber 102, the decrease in contrast can be suppressed, as in the second embodiment. Of course, as in the second embodiment, a light absorber in a semi-transmissive state or a polarizing plate whose absorption axis is shifted from the polarization separators 101 and 121 can be used.

<Light Source> The various light sources described in FIGS. 5 to 9 and the first embodiment can be used for the display device in the present embodiment.

Since the operation and effect are the same as those of the first embodiment, the description is omitted here.

(Fifth Embodiment) FIG. 14 is a sectional view of a display device according to a fifth embodiment of the present invention.
FIG. 5 is a schematic sectional view for explaining the display principle of the display device according to the first embodiment of the present invention.

The display device 100 can perform a reflection type display utilizing the reflection of external light in a place where external light exists, and a transmission type display using light from a light source even in a place where external light does not exist. This is a reflective display device having a so-called semi-transmissive function capable of displaying.

<Basic Structure> First, the structure of the display device of the present embodiment will be described with reference to FIG. This display device 14
In OO, a TN liquid crystal panel 10 is used as a variable transmission polarization axis optical element. In the TN liquid crystal panel 10, a TN liquid crystal 13 is sandwiched between two glass plates 11 and 12, and a plurality of character display units (not shown) are provided so that characters can be displayed. TN
On the upper side of the liquid crystal panel 10, a fan plate 14 is provided. On the lower side of the TN element panel 10, a light scatterer 15, a polarization separator 16, a diffusion plate 140, and a light source 17 are provided in this order. Note that a scattering plate that can change the polarization state of incident light and emit the light is used as the diffusion plate 140. Further, a TAB board (not shown) on which a driver IC for driving the TN liquid crystal 13 is mounted is connected to the TN liquid crystal panel 10 to constitute a display device.

<Polarization Separator> In this embodiment, the same one as described in the first embodiment with reference to FIGS. 3 and 4 is used. Here, the detailed description is omitted. Of course, besides this polarization separator, for example, a cholesteric liquid crystal layer sandwiched between λ / 4 plates, a device using Brewster's angle (SID 92DIGEST pages 427 to 429), a device using a hologram, and the like are used. It has the same function as the above-described polarization separator, and may be used for the display device of the present embodiment.

<Display Principle> Next, the display by the display device 1400 will be described with reference to FIG. 15, in which the right half of the display device 1400 is a voltage application unit and the left half is a voltage non-application unit.

First, a reflection type display when external light is incident on the display device 1400 will be described.

In the left non-voltage application section, when external light is incident on the display device 1400, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the sheet of paper.
The polarization direction is twisted by 90 ° by the TN liquid crystal 13 to be linearly polarized light in a direction perpendicular to the paper surface, and is reflected by the polarization separator 16 as linearly polarized light in a direction perpendicular to the paper surface, so that the TN liquid crystal 13
As a result, the polarization direction is twisted by 90 ° to become linearly polarized light in a direction parallel to the paper surface, and is emitted from the polarizing plate 14 as linearly polarized light in a direction parallel to the paper surface. As described above, when no voltage is applied, the incident external light is reflected instead of being absorbed by the polarization separator 16, so that a bright reflective display is obtained. Since the light scatterer 15 is provided between the polarization separator 16 and the TN liquid crystal panel 10, the polarization separator 1
The reflected light from 6 changes from a mirror surface state to a white state.

In the voltage application section on the right side, when external light enters the display device 1400, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the sheet of paper.
The N liquid crystal 13 is transmitted without changing the polarization direction,
6 is also transmitted without changing the polarization direction.
Changes its polarization state and is scattered. Scattered sheets 14
Since the state of polarization of the light scattered toward the polarization separator due to 0 has been eliminated, most of the light cannot pass through the polarization separator, resulting in a dark display.

As described above, in the reflection type display when external light is incident on the display device 1400, the light reflected by the polarization splitter 16 is applied to the light scatterer 1 in the no-voltage application section.
5 and a bright display is obtained, and in the voltage application unit, the light transmitted through the polarization separator 16 is scattered by the scattering state of the scattering state by the scattering plate 140, so that a dark display is obtained.

When no voltage is applied, the external light incident on the display device 1400 is reflected without being absorbed by the polarization separator 16, so that a bright display is obtained.

Next, a transmission type display using light from the light source 17 will be described.

In the left non-voltage application section, the light source 17
Is incident on the polarization separator 16 via the scattering plate 140, is converted into linearly polarized light in a direction parallel to the paper by the polarization separator 16, and then the polarization direction is changed to 9 by the TN liquid crystal 13.
The light is twisted by 0 ° and becomes a linearly polarized light in a direction perpendicular to the plane of the paper, and is absorbed by the polarizing plate 14 to provide a dark display.

In the voltage application section on the right side, light from the light source 17 enters the polarization separator 16 via the scattering plate 40,
The polarization separator 16 turns the light into linearly polarized light in a direction parallel to the plane of the paper, and the light scatterer 15 turns the light into scattered light.
The N liquid crystal 13 is transmitted without changing the polarization direction, and the polarizing plate 14 is also transmitted, thereby providing a bright display.

As described above, in the transmission type display using the light from the light source 17, the light from the light source 17 is absorbed by the polarizing plate 14 in the voltage non-applied portion, resulting in a dark display. A bright display is obtained through the plate 14.

Therefore, the display device 1400 can perform bright reflection type display utilizing the reflection of external light in a place where external light exists, and can display light from the light source 17 even in a place where there is no external light. , A reflection type display device having a so-called semi-transmission type function.

<Scattering Plate> As the scattering plate used in the display device of this embodiment, a scattering plate capable of emitting incident light without minimizing the polarization state is used. still,
Since this scattering plate has a function of scattering and fogging light emitted from the scattering plate, a display device with a cloudy display (white display) can be obtained. On the other hand, if the scattering plate 15 is removed from the configuration, the display device can display a glossy color. Therefore, the scattering plate may be removed according to the use of the display device.

<Light Source> Various light sources described in FIGS. 5 to 9 and the first embodiment can be used for the display device of the present embodiment. Both action and effect
1 is the same as in the embodiment, and the description is omitted here.

(Sixth Embodiment) FIG. 16 is a sectional view of a display device according to a sixth embodiment of the present invention.
FIG. 7 is a schematic sectional view for explaining the display principle of the display device according to the sixth embodiment of the present invention.

This display device 1600 can perform a reflection type display utilizing the reflection of external light in a place where external light exists, and a transmissive type display using light from a light source even in a place where external light does not exist. This is a reflective display device having a so-called semi-transmissive function capable of displaying.

<Basic Structure> First, the structure of the display device of the present embodiment will be described with reference to FIG. This display device 16
In OO, a TN liquid crystal panel 10 is used as a variable transmission polarization axis optical element. In the TN liquid crystal panel 10, a TN liquid crystal 13 is sandwiched between two glass plates 11 and 12, and a plurality of character display units (not shown) are provided so that characters can be displayed. A polarizing plate 14 is provided above the TN liquid crystal panel 10.
On the lower side of the TN element panel 10, a light scatterer 15, a polarization separator 16, a colored film 160 as a colored layer, and a light source 60 are provided in this order. The colored film is a semi-transmissive film that can change the polarization state of incident light having a predetermined wavelength and emit the light, and can absorb light having a wavelength other than the predetermined wavelength. Was used. Further, a TAB board (not shown) on which a driver IC for driving the TN liquid crystal 13 is mounted is connected to the TN liquid crystal panel 10 to constitute a display device.

<Polarization Separator> In this embodiment, the same one as described in the first embodiment with reference to FIGS. 3 and 4 is used. Here, the detailed description is omitted. Of course, besides this polarization separator, for example, a cholesteric liquid crystal layer sandwiched between λ / 4 plates, a device using a Brewster's angle (SID 92DIGEST pages 427 to 429), a device using a hologram, and the like Have the same function as the above-described polarization separator, and may be used for the display device of the present embodiment.

<Display Principle> Next, referring to FIG. 17, a display by the display device 1600 will be described in which the right half of the display device 1600 is a voltage application section and the left half is a voltage non-application section.

First, a reflection type display when external light is incident on the display device 1600 will be described.

In the left non-voltage application section, when external light is incident on the display device 1600, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the sheet of paper.
The polarization direction is twisted by 90 ° by the TN liquid crystal 13 to become linearly polarized light in a direction perpendicular to the paper surface, and is reflected by the polarization separator 16 as linearly polarized light in the direction perpendicular to the paper surface, and the polarization direction is 90 ° by the TN liquid crystal 13. It is twisted and becomes linearly polarized light in a direction parallel to the paper surface, and is emitted from the polarizing plate 14 as linearly polarized light in a direction parallel to the paper surface. As described above, when no voltage is applied, the incident external light is reflected instead of being absorbed by the polarization separator 16, so that a bright reflective display is obtained. Since the light scatterer 15 is provided between the polarization separator 16 and the TN liquid crystal panel 10, the polarization separator 16
The light reflected from the mirror becomes white from a mirror-like state.

In the right voltage application section, when external light is incident on the display device 1600, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the paper surface.
The N liquid crystal 13 is transmitted without changing the polarization direction,
6 also transmits without changing the polarization direction, and thereafter, light within a predetermined wavelength range is absorbed by the colored film 160. Since the light in the predetermined wavelength range is absorbed by the colored film, a dark display is obtained.

As described above, in the reflection type display when the external light is incident on the display device 1600, the light reflected by the polarization separator 16 is applied to the light scatterer 1 in the voltage non-applying portion.
5 and a bright display is obtained, and in the voltage application section, the light transmitted through the polarization separator 16 is absorbed by the colored film 50, so that a dark display is obtained.

When no voltage is applied, external light incident on the display device 1600 is reflected by the polarization separator 16 without being absorbed, so that a bright display is obtained.

Next, a transmission type display using light from the light source 17 will be described.

In the left non-voltage application section, the light source 17
From the polarization separator 16 through the colored film 160.
, And is converted into linearly polarized light in a direction parallel to the paper surface by the polarization separator 16, and then the polarization direction is twisted by 90 ° by the TN liquid crystal 13 to become linearly polarized light in a direction perpendicular to the paper surface, and is absorbed by the polarizing plate 14. The display becomes dark.

In the voltage application section on the right side, the light from the light source 17 enters the polarization separator 16 while being colored by passing through the coloring film 160, and is converted into linearly polarized light in a direction parallel to the paper by the polarization separator 16. , Light scatterer 1
5, the light becomes scattered light, and then transmits through the TN liquid crystal 13 without changing the polarization direction, and also transmits through the polarizing plate 14 to provide a bright display.

As described above, in the transmission type display using the light from the light source 17, the light from the light source 17 is absorbed by the polarizing plate 14 in the voltage non-applied portion to make the display dark, and the light in the voltage applied portion is not polarized. A bright display is obtained through the plate 14.

Therefore, the display device 1600 can perform bright reflection type display utilizing the reflection of external light in a place where external light exists, and can display light from the light source 17 even in a place where there is no external light. , A reflection type display device having a so-called semi-transmission type function.

<Scattering Plate> As the scattering plate used in the display device according to the present embodiment, a scattering plate capable of emitting incident light without minimizing the polarization state is used. In addition, since this scattering plate has a function to scatter and cloud light emitted from the scattering plate, a display device having a cloudy display (white display) can be obtained. On the other hand, if the scattering plate 15 is removed from the configuration, the display device can display a glossy color. Therefore, the scattering plate may be removed according to the use of the display device.

<Colored Layer> FIGS. 18 and 19 show a display device of this embodiment in which various colored films are used as colored layers. In the present embodiment, FIG.
19 and any of the colored films shown in FIG. 19 can be used. The display device shown in FIG. 18 employs a colored film that transmits and reflects red wavelength light. In the display device shown in FIG. 18, in the reflection type display, blackish red display is obtained in the voltage application section, and white display is performed in the non-voltage application section. On the other hand, in the transmission type display using light from the light source, the display of the light color of the light source colored by the colored film in the voltage application unit, that is, the red display, and the black display in the non-voltage application unit.

By the way, in the case where a colored film is not used and a light source emitting white light is used, as described above, a dark display is obtained in the voltage non-applied portion with respect to the light from the light source 17, and A bright display can be obtained in the application section, and a transmissive display can be obtained. In this case, when external light enters from the front side of the display device, the external light causes a bright display in the no-voltage application section. , And dark display occurs in the voltage application section. as a result,
In any of the voltage non-applying section and the voltage applying section, for example, when the display by the transmitted light from the light source 17 is a bright display, the reflection type dark display by the external light is added, and the display becomes gray. Even in the case where the display by the transmitted light is dark, the reflection type bright display by the external light is added and the display becomes gray again, so-called a positive-negative inversion phenomenon occurs, and the display may be difficult to see.

When the light source is turned on using the color filter shown in FIG. 18 when external light is incident, the light applied from the light source 17 that has passed through the color filter 160 at the voltage application unit can be seen, and the display becomes grayish red. In the portion where no voltage is applied, the external light reflected by the polarization separator is visible, so that the display becomes gray, which is much easier to see than a simple monochrome display.

In FIG. 18, a colored filter that reflects or transmits light of a red wavelength is used. However, light of a wavelength other than red may be used.

In the display device shown in FIG. 19, a colored film having a region that reflects and transmits red wavelength light and a region that reflects and transmits blue wavelength light is disposed as a colored layer. Each region is arranged such that the emitted light corresponds to each character display section formed on the liquid crystal panel. When the colored film shown in FIG. 19 is used in the display device of the present embodiment, black display is performed in a voltage application part and white display is performed in a non-voltage application part in a reflective display. On the other hand, for the transmission type display using light from the light source, in the voltage application unit, each character display unit displays the color of light emitted from each region of the corresponding colored film, that is, displays red or blue, and in the voltage non-application unit, The display becomes black. When the light source is turned on when external light is incident using the light source shown in FIG. 19, light emitted from each LED group can be seen in the voltage application unit, so that each character display unit has a grayish red or blue display. In the non-voltage-applied section, the external light reflected by the polarization splitter is visible, so that the display is gray. In FIG. 19, a colored film that transmits or reflects red wavelength light and a colored film that reflects or transmits blue wavelength light are used. Of course, a colored film that reflects or transmits light having wavelengths other than these colors is used. It does not matter, and a combination thereof can be appropriately selected.

(Seventh Embodiment) FIG. 20 is a sectional view of a display device according to a seventh embodiment of the present invention.
FIG. 1 is a schematic sectional view for explaining the display principle of a display device according to a seventh embodiment of the present invention.

This display device 2000 can perform a reflection type display utilizing the reflection of external light in a place where external light exists, and a transmission type display using light from a light source even in a place where external light does not exist. This is a reflective display device having a so-called semi-transmissive function capable of displaying.

<Basic Structure> First, the structure of the display device of the present embodiment will be described with reference to FIG. This display device 20
In OO, a TN liquid crystal panel 10 is used as a variable transmission polarization axis optical element. In the TN liquid crystal panel 10, a TN liquid crystal is sandwiched between two glass plates, and a plurality of character display units 201 and 202 are provided to enable character display. A polarizing plate 14 is provided above the TN liquid crystal panel 10. On the lower side of the TN liquid crystal panel 10, a light scatterer 15, a polarization separator 1
6, a light absorber 200 in a gray semi-transmissive state, a colored film 160 as a colored layer, and a light source 17 are provided in this order. Further, a TAB substrate (not shown) on which a driver IC for driving the TN liquid crystal is mounted is frozen on the TN liquid crystal panel 10 to constitute a display device.

<Polarization Separator> In this embodiment, the same one as described in the first embodiment with reference to FIGS. 3 and 4 is used. Here, the detailed description is omitted. Of course, in addition to this polarization separator, for example, a cholesteric liquid crystal layer sandwiched between λ / 4 plates, a worm using the brewster angle (SID 92DIGEST, pp. 427 to 429), a hologram using a hologram, and the like Have the same function as the above-described polarization separator, and may be used for the display device of the present embodiment.

<Display Principle> Next, referring to FIG. 21, a display by the display device 2000 will be described in which the right half of the display device 2000 is a voltage application portion and the left half is a voltage non-application portion.

First, a reflection type display when external light is incident on the display device 2000 will be described.

In the left non-voltage application section, when external light enters the display device 2000, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the paper surface.
The polarization direction is twisted by 90 ° by the TN liquid crystal 13 to be linearly polarized light in a direction perpendicular to the paper surface, and is reflected by the polarization separator 16 as linearly polarized light in a direction perpendicular to the paper surface.
As a result, the polarization direction is twisted by 90 ° to become linearly polarized light in a direction parallel to the paper surface, and is emitted from the polarizing plate 14 as linearly polarized light in a direction parallel to the paper surface. As described above, when no voltage is applied, the incident external light is reflected instead of being absorbed by the polarization separator 16, so that a bright reflective display is obtained. Since the light scatterer 15 is provided between the polarization separator 16 and the TN liquid crystal panel 10, the polarization separator 1
The reflected light from 6 changes from a mirror surface state to a white state.

In the voltage application section on the right side, when external light enters the display device 2000, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the paper surface.
The N liquid crystal 13 is transmitted without changing the polarization direction,
6 also transmits without changing the polarization direction, and is thereafter absorbed by the light absorber 200 in a semi-transmissive state, resulting in a dark display.

As described above, in the reflection type display when external light is incident on the display device 2000, the light reflected by the polarization separator 16 is applied to the light scatterer 1 in the no-voltage application section.
5 and a bright display is obtained. In the voltage application unit, the light transmitted through the polarization separator 16 is partially transmissive by the light absorber 160.
And the display becomes dark.

When no voltage is applied, the external light incident on the display device 2000 is reflected without being absorbed by the polarization separator 16, so that a bright display is obtained.

Next, a transmission type display using light from the light source 17 will be described.

In the left non-voltage application section, the light source 17
Light passes through the light absorber 160 in a semi-transmissive state, passes through the colored film, and is incident on the polarization separator 16 while being colored, and is converted into linearly polarized light in a direction parallel to the paper by the polarization separator 16. Polarization direction is 9 by TN liquid crystal 13
The light is twisted by 0 ° and becomes a linearly polarized light in a direction perpendicular to the plane of the paper, and is absorbed by the polarizing plate 14 to provide a dark display.

In the voltage applying section on the right side, the light from the light source 17 passes through the light absorber 160 in a semi-transmissive state, enters the polarization separator 16 while being colored by the colored film, and is The light becomes scattered light by the light scatterer 15 and then passes through the TN liquid crystal 13 without changing the polarization direction, and also passes through the polarizing plate 14 to provide a bright display.

As described above, in the transmissive display using the light from the light source 17, the light from the light source 17 is absorbed by the polarizing plate 14 in the non-voltage-applied portion, resulting in a dark display. A bright display is obtained through the plate 14.

Therefore, the display device 2000 can perform bright reflection type display utilizing the reflection of external light in a place where external light exists, and can display light from the light source 17 even in a place where there is no external light. , A reflection type display device having a so-called semi-transmission type function.

<Light Absorber> The light absorber 200 of the present embodiment is similar to that used in the second embodiment, that is, the light absorber 200 in the second embodiment, in addition to the light absorber in the semi-transmissive state. A light absorber provided with an opening can also be used. Also, by limiting the ratio of the opening to the light absorber, a decrease in contrast can be suppressed as in the second embodiment. Of course, similarly to the second embodiment, a polarizing plate whose absorption axis is shifted from that of the polarization separator 16 can be used.

<Colored Layer> In the display device of this embodiment, various colored films described in FIGS. 18, 19 and 6 can be used as the colored layer. Since the operation and effect are the same as in the sixth embodiment, the description is omitted here.

(Eighth Embodiment) FIG. 22 is a sectional view of a display device according to an eighth embodiment of the present invention.
FIG. 3 is a schematic sectional view for explaining the display principle of the display device according to the eighth embodiment of the present invention.

This display device 2200 can perform a reflection type display utilizing reflection of external light in a place where external light exists, and a transmission type display using light from a light source even in a place where external light does not exist. This is a reflective display device having a so-called semi-transmissive function capable of displaying.

<Basic Structure> First, the structure of the display device of the present embodiment will be described with reference to FIG. This display device 2
200, TN as a transmission polarization axis variable optical element
The liquid crystal panel 10 is used. In the TN liquid crystal panel 10, a TN liquid crystal is sandwiched between two glass plates, and a plurality of character display units 201 and 202 are provided so that characters can be displayed. A polarizing plate 14 is provided above the TN liquid crystal panel 10. On the lower side of the TN device panel 10, a polarization separator 16, a coloring film 160 as a coloring layer, a reflector 220 having an opening, and a light source 17 are provided in this order. The reflection plate 22
0 indicates that a plurality of openings 221 are provided at a predetermined area density. Further, a TAB substrate (not shown) on which a driver IC for driving the TN liquid crystal is mounted is connected to the TN liquid crystal panel 10 to constitute a display device.

<Polarization Separator> In this embodiment, the same one as described in the first embodiment with reference to FIGS. 3 and 4 is used. Here, the detailed description is omitted. Of course, besides this polarization separator, for example, a cholesteric liquid crystal layer sandwiched between λ / 4 plates, a device using a Brewster's angle (SID 92DIGEST pages 427 to 429), a device using a hologram, and the like Have the same function as the above-described polarization separator, and may be used for the display device of the present embodiment.

<Display Principle> Next, the display by the display device 2200 will be described with reference to FIG. 23, in which the right half of the display device 2200 is a voltage application section and the left half is a voltage non-application section.

First, a reflection type display when external light is incident on the display device 2200 will be described.

In the left non-voltage application section, when external light is incident on the display device 2200, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the sheet of paper.
The polarization direction of the TN liquid crystal 13 becomes 90 ° and becomes linearly polarized light in a direction perpendicular to the plane of the paper. The polarized light is reflected by the polarization separator 16 as linearly polarized light in a direction perpendicular to the plane of the paper.
As a result, the polarization direction is twisted by 90 ° to become linearly polarized light in a direction parallel to the paper surface, and is emitted from the polarizing plate 14 as linearly polarized light in a direction parallel to the paper surface. As described above, when no voltage is applied, the incident external light is reflected instead of being absorbed by the polarization separator 16, so that a bright reflective display is obtained.

In the voltage application section on the right side, when external light enters the display device 2200, the external light is converted by the polarizing plate 14 into linearly polarized light in a direction parallel to the sheet of paper.
The N liquid crystal 13 is transmitted without changing the polarization direction,
6 also transmits without changing the polarization direction, and a part of the
The TN liquid crystal 140 is reflected by 60, passes through the polarization separator 160 again, and remains linearly polarized in a direction parallel to the plane of the paper.
Is transmitted without changing the polarization direction, and is emitted from the polarizing plate 14 as linearly polarized light in a direction parallel to the paper surface. A part of the light emitted from the polarization separator 16 is transmitted through the coloring layer 160 while being absorbed by the coloring layer 160, is reflected by the reflection plate 220, and is then absorbed by the coloring layer 160 again to form the coloring layer 160. The TN liquid crystal 13 passes through the polarization separator 16 again as linearly polarized light in a direction parallel to the paper surface.
Is transmitted without changing the polarization direction, and is emitted from the polarizing plate 14 as linearly polarized light in a direction parallel to the plane of the paper, thereby producing a colored display.

Next, a transmission type display using light from the light source 17 will be described.

In the left non-voltage application section, the light source 17
Is incident on the polarization separator 16 while being colored by the coloring film through the opening 221 provided in the reflection plate 220, and is converted into linearly polarized light in a direction parallel to the paper by the polarization separator 16, 13 makes the polarization direction 9
The light is twisted by 0 ° and becomes a linearly polarized light in a direction perpendicular to the plane of the paper, and is absorbed by the polarizing plate 14 to provide a dark display.

In the voltage application section on the right side, the light from the light source 17 passes through the opening 221 provided in the reflection plate 200, enters the polarization separator 16 while being colored by the coloring layer 160, and As a result, the polarized light becomes a linearly polarized light in a direction parallel to the paper surface, and then transmits the TN liquid crystal 13 without changing the polarization direction, and also transmits through the polarizing plate 14 to provide a colored bright display.

As described above, in the transmissive display using the light from the light source 17, the light from the light source 17 is absorbed by the polarizing plate 14 in the non-voltage-applied portion, resulting in a dark display. A bright display is obtained through the plate 14.

Therefore, the display device 2200 can perform bright reflection type display utilizing the reflection of external light in a place where external light exists, and can display light from the light source 17 even in a place where there is no external light. , A reflection type display device having a so-called semi-transmission type function.

<Reflective Plate> An Al reflective plate or the like can be used for the display device of the present embodiment. Further, a half mirror or the like may be used instead of the reflection plate provided with the opening.

<Coloring Layer> For the display device in this embodiment, the various coloring films described in FIGS. 18, 19 and the sixth embodiment can be used. Action
Since the effect is the same as that of the sixth embodiment, the description is omitted here.

(Ninth Embodiment) FIG. 25 is a perspective view of a mobile phone using the display device introduced in the first to eighth embodiments of the present invention as a display unit.
In the figure, (a) shows a mobile phone, and (b) shows a wristwatch.

In this embodiment mode, a mobile phone and a wristwatch have been described, but the display device of the present invention can use various electronic devices such as a personal computer, a car navigation system, and an electronic organizer.

Although only the dark display, the bright display and the color display have been described in the first to ninth embodiments, it is natural that the display device of each embodiment can perform the halftone display. That is.

In the first to ninth embodiments, the TN liquid crystal panel 10 has been described as an example of the transmission polarization axis changing means. However, an STN liquid crystal element, an ECB liquid crystal element, or the like may be used. As the STN liquid crystal element, an STN liquid crystal element using an optically anisotropic body for color compensation, such as an F-STN liquid crystal element, is preferably used.

In the first to ninth embodiments, preferably, the distance between the polarization splitter and the light source is increased to reduce the amount of light reflected by the light source and returned again. And a decrease in contrast can be suppressed.

In the second to fifth and seventh to eighth embodiments, the light transmitted through the light absorber can also be increased by increasing the distance between the light absorber or the scattering plate and the light source. The amount of light reflected back by the light source and returned again can be reduced, and a decrease in contrast can be suppressed.

In the first to eighth embodiments, reflection of the light source surface can be suppressed by darkening the surface color of the light source, and as a result, the light transmitted through the light absorber can be reduced. The amount of light reflected back and returned again can be reduced, and a decrease in contrast can be suppressed.

In the second to fifth and seventh embodiments, the bright display by the light reflected by the polarization separator is a display by the light reflected by the polarization separator. It is not affected by the structure of the light absorber disposed behind the polarization separator.

Further, in the display devices shown in the first to fifth embodiments, means for condensing light from a light source toward the front of the display device may be further provided.

[0209] Normally, when viewing a reflection type display by external light, the display is performed at a position inclined at a certain angle from the normal to the front of the display device. If the display is viewed from the normal direction to the front of the display device, the external light incident on the display device is obstructed by the observer himself, so that the reflection type display by the external light becomes dark. On the other hand, when viewing the display by the transmitted light from the light source, since it is usually viewed from the normal direction to the front of the display device, means for condensing the light from the light source toward the front of the display device is used. With the provision, the display by the light transmitted from the light source can be brightened. As a result, the transmissive display by the light from the light source can be easily seen in the normal direction to the front of the display device. As means for condensing the light from the light source toward the front of the display device, for example, a prism sheet is suitably used. Regarding the position where this prism sheet is arranged, it is preferable to provide a light source and a polarization separator in the first to fifth embodiments, and in the sixth to eighth embodiments, as shown in FIG. It is preferable to provide between the light source and the colored film.

[0210] In the display device of the present invention, for light incident from outside the first polarization separation means, the second polarization separation means is changed according to the state of the transmission polarization axis of the transmission polarization axis changing means. A first display state by the light reflected from the optical element, and a second display state of a state in which the light transmitted through the second polarization separation unit is absorbed by the optical element. It becomes a reflective display device. The first display state is a display state due to light reflected from the second polarization splitting means, so that a bright display is obtained.

Further, with respect to the light from the light source, the third display state by the light transmitted through the first polarization separation means and the first display state correspond to the state of the transmission polarization axis of the transmission polarization axis changing means.
And a fourth display state in which light does not pass through the polarization separation means, and a transmission type display can be obtained.

As described above, in the display device of the present invention, in a place where external light exists, a bright reflective display utilizing reflection of the external light can be displayed, and in a place where there is no external light. A transmissive display using light from a light source can be performed.

The second polarized light separating means is used to detect the linearly polarized light in the third predetermined direction out of the light incident from the transmitted polarization axis changing means side with respect to the light in substantially the entire wavelength range of the visible light region. Transmitting the polarized light component to the optical element side;
The linearly polarized light component in the fourth predetermined direction orthogonal to the predetermined direction is reflected toward the transmission polarization axis variable unit, and is light in substantially the entire wavelength range of a visible light region, and is incident from the optical element side. On the side of the transmission polarization axis variable unit with respect to light, the third
The first to fourth display states are obtained with respect to light in the entire wavelength range of the visible light region by using a polarization separating unit capable of emitting linearly polarized light in a predetermined direction. In the third display state, a transparent or bright display can be obtained.

Further, by making the optical element an optical element that absorbs light in almost the entire wavelength range of the visible light region, and particularly by using a black light absorber, a dark display can be obtained in the second and fourth display states. Obtainable.

[Brief description of the drawings]

FIG. 1 is a sectional view of a display device according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view for explaining the display principle of the display device according to the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a polarization separator 16 used in the present embodiment.

FIG. 4 is a diagram illustrating the operation of the polarization separator 16 shown in FIG.

FIG. 5 is a diagram showing an example of a light source used in the present invention.

FIG. 6 is a diagram showing another example of the light source used in the present invention.

FIG. 7 is a diagram showing another example of a light source used in the present invention.

FIG. 8 is a diagram showing another example of the light source used in the present invention.

FIG. 9 is a diagram showing another example of the light source used in the present invention.

FIG. 10 is a sectional view of a display device according to a second embodiment of the present invention.

FIG. 11 is a schematic sectional view for explaining a display principle of a display device according to a second embodiment of the present invention.

FIG. 12 is a schematic cross-sectional view illustrating a display device according to a third embodiment of the present invention.

FIG. 13 is a schematic cross-sectional view illustrating a display device according to a fourth embodiment of the present invention.

FIG. 14 is a sectional view of a display device according to a fifth embodiment of the present invention.

FIG. 15 is a schematic sectional view for explaining the display principle of the display device according to the first embodiment of the present invention.

FIG. 16 is a sectional view of a display device according to a sixth embodiment of the present invention.

FIG. 17 is a schematic sectional view for explaining the display principle of the display device according to the sixth embodiment of the present invention.

FIG. 18 is a diagram showing an example of a colored layer used in the present invention.

FIG. 19 is a view showing another example of a colored layer used in the present invention.

FIG. 20 is a sectional view of a display device according to a seventh embodiment of the present invention.

FIG. 21 is a schematic cross-sectional view for explaining a display principle of a display device according to a seventh embodiment of the present invention.

FIG. 22 is a sectional view of a display device according to an eighth embodiment of the present invention.

FIG. 23 is a schematic sectional view for explaining a display principle of a display device according to an eighth embodiment of the present invention.

FIG. 24 is a diagram showing an example in which a prism sheet is combined with the display device of the present invention.

FIG. 25 is a diagram illustrating an example of an electronic apparatus including the display device of the present invention as a display unit.

FIG. 26 is a diagram illustrating an example of a conventional display device.

Claims (36)

[Claims] A first and a second polarization separation means disposed on both sides of the transmission polarization axis changing means with the transmission polarization axis variable means interposed therebetween; A light source disposed on the opposite side of the transmission polarization axis variable unit with respect to the second polarization separation unit, wherein the first polarization separation unit is the second of the first polarization separation unit.
The linearly polarized light component in a first predetermined direction of the light incident from the first side is transmitted as a linearly polarized light in the first predetermined direction to a second side facing the first side, and the first Of the light incident from the first side of the polarization separation means does not transmit a linear polarization component in a second direction different from the first direction to the second side, the first polarization separation. The linearly polarized light component in the first predetermined direction of the light incident from the second side of the means is transmitted to the first side as linearly polarized light in the first predetermined direction, and the first polarized light The linearly polarized light component in the second direction of the light incident from the second side
The second polarization separation means transmits a linearly polarized light component in a third predetermined direction of the light incident from the transmission polarization axis variable means side to the light source side. The linearly polarized light component in a fourth predetermined direction different from the third predetermined direction is reflected toward the transmission polarization axis variable unit, and the light incident from the light source side is transmitted through the transmission polarization axis variable unit. A display device, characterized by a polarization separating means capable of emitting linearly polarized light in the third predetermined direction on a side thereof. 2. The apparatus according to claim 1, wherein the second polarization separation unit is configured to generate a straight line in the third predetermined direction of light incident from the transmission polarization axis changing unit side with respect to light in substantially the entire wavelength range of a visible light region. A polarized light component is transmitted to the light source side, and a linearly polarized light component in the fourth predetermined direction different from the third predetermined direction is reflected toward the transmission polarization axis changing unit, so that a substantially 仝 wavelength in a visible light region is obtained. A polarization separating unit which is capable of emitting linearly polarized light in the third predetermined direction to the transmission polarization axis changing unit side with respect to light within a range and light incident from the light source side. The display device according to 1. 3. The second predetermined polarization separating means converts the linearly polarized light component in the third predetermined direction out of the light incident from the transmission polarization axis changing means side to the third predetermined predetermined direction toward the optical element. 3. The display device according to claim 2, wherein the display device is a polarization separation unit that transmits the linearly polarized light in the directions. 4. The second polarized light separating means is a multilayer film in which a plurality of layers are laminated, wherein the refractive indices of the plurality of layers are in a third predetermined direction between adjacent layers. 4. The display device according to claim 3, wherein the first and second directions are equal and different in a fourth predetermined direction. 5. The display device according to claim 1, wherein said first polarization separation means is a polarizing plate. 6. The display device according to claim 1, wherein the transmission polarization axis changing unit is a liquid crystal element. 7. The display device according to claim 6, wherein the transmission polarization axis changing means is a TN liquid crystal element, an STN liquid crystal element, an F-STN liquid crystal element, or an ECB liquid crystal element. 8. The display device according to claim 1, wherein a surface color of the light source is darkened. 9. The display device according to claim 1, wherein the light from the light source is colored. 10. Between the second polarization separation means and the light source, absorbs light from the second polarization separation means and transmits light from the light source to the second polarization separation means. 5. The display device according to claim 1, further comprising an optical element capable of transmitting light through the display. 11. The display device according to claim 10, wherein the optical element is an optical element that absorbs light in a substantially entire wavelength range of a visible light region. 12. The display device according to claim 11, wherein the optical element is a black light absorber. 13. The display device according to claim 10, wherein the optical element has an opening. 14. The display device according to claim 13, wherein a ratio of the opening to the optical element is limited. 15. The display device according to claim 13, wherein a distance between the optical element and the light source is greater than a diameter of the opening. 16. The display device according to claim 10, wherein the optical element is a light absorber in a gray semi-transmissive state. 17. The display device according to claim 16, wherein the light absorber in the semi-transmissive state has a transmittance of 10% or more and 80% or less with respect to light in almost the entire visible wavelength range. 18. The optical element according to claim 10, wherein the optical element is a light scatterer capable of changing a polarization state of light incident on the optical element and emitting the light from the optical element. Display device. 19. The optical device according to claim 19, wherein the optical element is a polarizing plate.
11. The display device according to claim 10, wherein the transmission axis of the polarization separation is not coincident with the transmission axis of the optical element. 20. The display device according to claim 1, further comprising a unit configured to condense light from the light source toward a front of the optical element. 21. The light condensing means, comprising: the light source;
21. The display device according to claim 20, wherein the display device is disposed between the first and second partial separation means. 22. The display device according to claim 1, further comprising a light diffusion unit between the transmission polarization axis changing unit and the second polarization separation unit. 23. A light source comprising: a cold cathode tube capable of emitting white light; and a light guide plate capable of emitting white light received and stored from the cold cathode tube to the second polarization separation unit. 5. The display device according to claim 1, wherein: 24. The display device according to claim 9, wherein the light source is an LED capable of emitting light in a predetermined wavelength region to the second polarization separation unit. 25. A light source comprising: a first LED capable of emitting light in a first predetermined wavelength range; and a second predetermined wavelength in a wavelength range different from the first predetermined wavelength range. The display device according to claim 24, further comprising a second LED capable of emitting light in a range. 26. The light source comprises: an LED capable of emitting light of a predetermined wavelength range; and a light guide plate capable of emitting light of the predetermined wavelength range incident from the LED to the second polarization separating unit. The display device according to claim 24, further comprising: 27. A light source comprising: a first LED capable of emitting light in a first predetermined wavelength range; and a second predetermined wavelength in a wavelength range different from the first predetermined wavelength range. The display device according to claim 26, further comprising a second LED capable of emitting light in a range. 28. The light guide plate, wherein light in the first predetermined wavelength range is incident from the first LED, and
A first light-guiding region that emits light in the first predetermined wavelength range on the side of the polarization separating means, and light in the second predetermined wavelength range is incident from the second LED, and A second light-guiding region that emits light in the second predetermined wavelength range on the side of the second polarization splitting means, between the first light-guiding region and the second light-guiding region. 28. The display device according to claim 27, further comprising a light shielding means. 29. The display device according to claim 9, wherein the light source is an EL element capable of emitting light in a predetermined wavelength range. 30. A light source comprising: a first EL element capable of emitting light in a third predetermined wavelength range; and a fourth predetermined wavelength in a wavelength range different from the third predetermined wavelength range. The display device according to claim 29, further comprising a second EL element capable of emitting light in a range. 31. Coloring between the light source and the second polarized light separating means, which is capable of transmitting or reflecting light in a predetermined wavelength range and absorbing light in a wavelength other than the predetermined wavelength range. 10. The display device according to claim 9, wherein a layer is provided. 32. The colored layer includes a first colored region capable of reflecting or transmitting light in a first predetermined wavelength range and a second predetermined region different from light in the first predetermined wavelength range. A second colored region capable of transmitting or reflecting light in a wavelength range, and capable of absorbing light having a wavelength outside the first or second predetermined wavelength range. Item 34. The display device according to Item 31. 33. Between the colored layer and the light source, light from the light source is transmitted to the colored layer side, is incident on the colored layer from the side of the second polarization separation means, and is transmitted through the colored layer. 32. The display device according to claim 31, further comprising a semi-transmissive reflection plate capable of reflecting light and emitting the light toward the colored layer. 34. The display device according to claim 33, wherein the transflective plate is a specular reflector provided with an opening. 35. The display device according to claim 9, wherein a display color based on light from the light source and a display color based on incident light from the first polarization splitting unit side are different. 36. An electronic apparatus comprising the display device according to claim 1 as a display unit.