JP2000131684A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high luminance and low power consumption semi- transmission type liquid crystal display element improving light utilization rate. SOLUTION: In the constitution arranging a phase difference plate 23 delaying a phase of an incident beam by a λ/4 and a liquid crystal layer 16 shifting the incident beam by λ/2 according to an applied voltage between a polarizing plate 24 and a selective reflection layer 18 consisting of the selective reflection layer such as a cholesteric liquid crystal confronted with this plate, a first color filter layer 21 is arranged on the polarizing plate side of the selective reflection layer 18. Further, e.g. a second color filter layer 22 is arranged on the rear side as a band-pass filter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color liquid crystal display device having a color filter, and more particularly to a back light source,
Also, the present invention relates to a transflective color liquid crystal display device capable of displaying transmitted light from the back among reflective color liquid crystal display devices provided with a reflection plate for reflecting external light.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been used in notebook computers (PCs), monitors, car navigation systems, scientific calculators, and the like.
It is applied to various fields such as small and medium TVs. Above all, the reflection type liquid crystal display element is being studied for application to a display for a portable device such as a mobile PC in order to take advantage of low power consumption, thinness and light weight since a back light source (backlight) is unnecessary. . However, the conventional reflection type liquid crystal display element uses external light similarly to paper, and therefore, if the environment itself is dark, the display screen becomes dark and cannot be used. In particular, it cannot be used at all in the dark.

In order to solve such a problem, a transflective liquid crystal display device having a back light source using a reflector as a transflective reflector, for example, a half mirror, has been developed so that it can be used as a transmissive liquid crystal display device in a dark environment. Was.

Further, a transflective liquid crystal display device using a microlens provided for each pixel by providing a pinhole for each pixel on a reflection plate is being studied. When used as a reflective liquid crystal display device, the brightness of the display screen is reduced only by the amount of pinholes as compared with a reflective liquid crystal display device. When used as a transmissive liquid crystal display device, a light emitted from a rear light source by the microlens is condensed by the microlens and passed through the pinhole to obtain a display screen brightness similar to that of a transmissive liquid crystal display element. The brightness of the above-mentioned transflective liquid crystal display device is improved.

[0005] Such a transflective liquid crystal display device can provide a color display by being provided with a color filter. FIG. 13 is a diagram showing a cross-sectional structure of a conventional transflective color liquid crystal display device. A polarizing plate 1, a front substrate 2, a color filter 3, an electrode 4, a liquid crystal layer 5, a rear substrate 6, a semi-reflective plate 7, and a rear light source 8 are arranged in this order.

FIG. 14 shows an example of the spectral characteristics of the RGB color filters used for this. As shown in FIG. 13, the color filter is provided in front of the reflection plate, on the observer side, and when functioning as a reflection type, follows the optical path indicated by the arrow (A). That is, the light path passes through the color filter 3 twice. Therefore, as with the reflection type color liquid crystal display device, the color filter only needs to have spectral characteristics such that desired color is obtained when the color filter is transmitted twice. Light that functions as a reflection type is external light, and the light intensity cannot be freely controlled. When a polarizing plate or the like is used, the transmittance of the entire device is not sufficient. Therefore, as shown in FIG. 15, when the maximum transmittance is 1 and the minimum transmittance is 0.1 or more, the color The filter spectral characteristics are designed so that the spectral characteristics when transmitted once through the color filter are such that the color density is so light that sufficient coloring cannot be obtained.

In fact, as shown in FIG. 16, even if the spectral characteristics when the light is transmitted twice through the color filter, the conventional transmission type R
The design is lighter in color density than the spectral characteristics (FIG. 15) of the GB color filter.

When used as a reflection type, such a spectral characteristic may be used in consideration of the brightness of the display. However, when this is used as a transmission type, an optical path indicated by an arrow (B) as shown in FIG. Is transmitted only once. Therefore, the spectral characteristic of the display when functioning as a transmission type is the spectral characteristic when transmitted once through the color filter, that is, the spectral characteristic of the color filter itself, resulting in an extremely light color density.

Conversely, if a color filter having a spectral characteristic used in a conventional transmission type as shown in FIG. 15 is used, when it functions as a reflection type, the display brightness becomes extremely insufficient.

[0010]

As described above, the conventional transflective color liquid crystal display device has a significantly reduced display brightness when functioning as a reflective type, or a display color when functioning as a transmissive type. The density was remarkably faint or only one of the optical characteristics was obtained. An object of the present invention is to solve these problems with a novel structure, and to provide a method capable of obtaining sufficient display brightness and color density both when functioning as a reflection type and when functioning as a transmission type.

[0011]

SUMMARY OF THE INVENTION The present invention is directed to a front substrate and a rear substrate having liquid crystal driving electrodes formed on their inner surfaces, respectively, which are opposed to each other, and sandwiched between the front substrate and the rear substrate. A liquid crystal layer that modulates the phase of the incident light according to the voltage, a retardation plate and a polarizing plate having a polarization axis that are sequentially mounted on the outer surface of one substrate, and a first plate of the incident light that is formed on the other substrate. A selective reflection layer that reflects a circularly polarized light component and transmits a second circularly polarized light component that is opposite to the first circularly polarized light component, a back light source disposed on the back of the back substrate, and the front substrate from the selective reflection layer A liquid crystal display device comprising: a first color filter layer disposed on a side of the liquid crystal display; and a bandpass filter disposed on the side of the rear light source relative to the selective reflection layer.

[0012] Further, the band-pass filter may have a structure in a transmission wavelength region of any of the color filter layers.
An object of the present invention is to provide a liquid crystal display device having a spectral transmittance characteristic in a narrower band than the color filter layer.

Further, a liquid crystal display device characterized in that the bandpass filter comprises a second color filter in which a plurality of color absorption filter layers each having a different spectral transmittance characteristic are regularly arranged. Things.

[0014] Further, the band pass filter is an interference filter layer to obtain a liquid crystal display element.

Further, when the slow axis of the retardation plate is viewed from the front side of the polarizing plate, the slow axis is approximately four in a predetermined direction from the polarizing axis.
A liquid crystal display device characterized in that the retardation plates are arranged so as to form an angle of 5 °.

Further, the selective reflection layer is a cholesteric liquid crystal layer, which is a liquid crystal display device.

Furthermore, a swing direction of the cholesteric liquid crystal layer is opposite to a rotation direction from the polarization axis to the slow axis.

Further, the first color filter layer comprises:
A liquid crystal display element formed on the inner surface of the front substrate is obtained.

Further, the band pass filter is formed on an outer surface of the back substrate to obtain a liquid crystal display device.

Further, the band pass filter is provided under the selective reflection layer to obtain a liquid crystal display element.

Further, the second color filter layer comprises:
A liquid crystal display device characterized by being colored by adding a dye to the selective reflection film or the like.

The band-pass filter is located closer to the rear light source than the selective reflection layer. When functioning as a reflection type, since the incident light passes through the first color filter twice, the spectral transmittance characteristic of the first color filter is set so as to be colored in a desired color in that state. Is done. Therefore, the spectral transmittance characteristic of the first color filter has a relatively wide band.

When functioning as a transmissive type, since the light from the light source passes through the first color filter only once, the light from the light source is projected beforehand by passing through a band-pass filter before entering the first color filter. By narrowing the band, display characteristics of brightness and color density similar to those of a conventional transmissive color liquid crystal display element can be obtained.

As such a band-pass filter,
A second color filter including a so-called interference filter and a color absorption filter can be used. As the interference filter, for example, a dielectric multilayer film in which a plurality of dielectrics are alternately stacked can be used. As the color absorption filter, for example, a filter obtained by adding a pigment or a dye to an organic medium can be used.

If the selective reflection layer is formed on the inner surface of the rear substrate and the color absorption filter is disposed below the selective reflection layer, no parallax due to the thickness of the substrate occurs, and there is a fear that the color density is reduced due to color shift. Absent.

When the second color filter is provided on an array substrate provided with active elements such as thin film transistors (TFTs), it is provided for forming pixel electrodes on gate lines, signal line lines, active elements, and the like. Since it can be used together as an interlayer insulating film, a high aperture ratio can be realized.

Further, by dispersing a pigment or mixing a dye into a selective reflection layer made of a cholesteric liquid crystal polymer or the like, the second color filter layer can function as the second color filter layer. Since the filter layer can be formed of one and the same layer, the number of layers can be reduced.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, the operating principle of the display element of the present embodiment will be described with reference to FIGS. The operation of the color filter will be described later.

The basic structure of the display element is, in order from the observation surface side, a polarizing plate 24 and a variable retarder (2) including a liquid crystal layer.
3, 16), and a structure in which the selective reflection layer 18 is laminated. The selective reflection layer 18 reflects only the left-handed circularly polarized light component or the right-handed circularly polarized light component of the incident light that reaches one main surface thereof, and transmits the component (right-handed polarized light component or left-handed polarized light component) opposite to the reflected component. Has a function of reflecting only a left-polarized component or a right-polarized component of incident light reaching the opposite main surface, and transmitting a right-polarized component or a left-polarized component.

When viewed from one principal surface side, the direction of rotation of the light reflected on the one principal surface side and the direction of rotation of the light transmitted from the back surface are equal, and the light transmitted on the back surface side and the light reflected on the back surface side are different from each other. The direction of rotation is also equal. As a selective reflection layer having such a function, a corsteric liquid crystal shown in FIG. 3 is known.
In FIG. 3, the rotation directions of the circularly polarized lights L1, L2, L1 ′, and L2 ′ are all observed from one principal surface 18f of the selective reflection layer 18.

That is, as shown in FIG. 3, when the cholesteric liquid crystal 19 constituting the selective reflection layer 18 has a counterclockwise spiral structure, natural light Lf incident from the main surface 18f side is used.
Of these, the left-handed circularly polarized light component is reflected by the main surface 18f. At this time, the reflected light L1 is emitted as clockwise circularly polarized light whose rotation direction is reversed with respect to the traveling direction due to reflection.
When viewed from the f side, it becomes left circularly polarized light. The right circularly polarized light component L2 of the incident light is transmitted to the other principal surface 18b. On the other hand, of the natural light Lb incident from the other main surface 18b, the left circularly polarized light component with respect to the traveling direction is reflected by the main surface 18b and the right circularly polarized light L2 ′ whose rotation direction is reversed with respect to the traveling direction is referred to as light L2 ′. Become. The right-handed circularly polarized light component passes through the selective reflection layer 18 with respect to the traveling direction. When this light is observed from the main surface 18f side, the light becomes the left-handed circularly polarized light component L1 ′.

In the display device according to the embodiment of the present invention, when external light enters from the observation surface side, a linearly polarized light component having a vibration direction along the polarization axis direction of the polarizing plate 24 is extracted.
Reach the variable retarder. The variable retarder ideally responds to the fixed retarder layer 23 that delays the phase of the vibration component in a specific direction of the incident light by λ / 4 (λ: the wavelength of the incident light) with respect to the vibration component orthogonal thereto, and according to the applied voltage. The variable retarder layer 16 is configured to delay the phase of the vibration component of the incident light in a specific direction relative to the vibration component orthogonal thereto by λ / 2.

As the fixed retarder layer 23, for example, a well-known λ / 4 retardation plate can be used, and its slow axis is formed at an angle of 45 ° with respect to the polarization axis of the polarizing plate 24 in a predetermined direction. The arrangement converts the linearly polarized light transmitted through the polarizing plate into circularly polarized light having a specific rotation direction. When the slow axis of the phase difference plate 23 is disposed so as to form an angle of 45 ° clockwise with respect to the polarization axis of the polarizing plate 24, the emitted circularly polarized light has clockwise polarity. Conversely, if the slow axis is arranged so as to make an angle of 45 ° counterclockwise to the polarization axis,
The emitted circularly polarized light has a counterclockwise polarity.

As the variable retarder layer 16, for example, a well-known twisted nematic (TN) liquid crystal layer is used. In a state where a voltage (first voltage) equal to or less than the threshold value is applied to the TN layer, that is, in a state where the liquid crystal layer maintains the initial alignment, the vibration component of the incident light in a specific direction becomes a vibration component in a direction orthogonal to the specific direction. In contrast, the rotation direction of the incident circularly polarized light is reversed. When a voltage (second voltage) higher than the saturation voltage is applied from the liquid crystal driving power supply 17 to the TN layer 16 and the twist state is released, the incident light is emitted without being phase-modulated, so that the polarity of the circularly polarized light is maintained as it is.

That is, when the variable retarder layer is formed of liquid crystal in the present embodiment, the phase delay due to the liquid crystal layer is relatively λ / 2 when the first voltage is applied and when the second voltage is applied. For example, in the case of a TN liquid crystal, for example, the first voltage is a voltage at which the liquid crystal exhibits an initial alignment state, and the second voltage is a state at which the twist of the liquid crystal is released. ), The phase of the incident light is delayed by λ / 4, and the phase is advanced by λ / 4 when a voltage (second voltage) higher than the saturation voltage is applied.

As an example, approximately 45 clockwise with respect to the polarization axis.
Λ / 4 retardation plate 23 having a slow axis crossing at an angle of °
A TN liquid crystal layer 16 disposed on the rear surface thereof; a selective reflection layer 18 formed of cholesteric liquid crystal having a left-hand twist disposed on the rear surface of the TN liquid crystal layer; and a back light source disposed on the rear surface of the selective reflection layer 18. In the case where the display element is constituted by using the first and second polarizers 25, first, the linearly polarized light that has reached the retardation plate 25 is
It is converted into right circularly polarized light and output.

When the first voltage is applied, that is, when the TN liquid crystal layer 16
In the F state, right circularly polarized light is converted into left circularly polarized light by the TN liquid crystal layer 16 and reaches the selective reflection layer 18. Then, the selective reflection layer 18 reflects the counterclockwise polarized light component viewed from the polarizing plate 24 according to the principle of FIG. The left circularly polarized light is again converted to right circularly polarized light by the TN liquid crystal layer 16, reaches the retardation plate 23, and is extracted as linearly polarized light that vibrates in the same direction as the incident linearly polarized light. Of the light source light incident from the rear surface of the selective reflection layer 18, the counterclockwise circularly polarized light component as viewed from the polarizing plate side passes through the selective reflection layer 18 and is converted into clockwise circularly polarized light by the TN liquid crystal layer 16. . Then, the light reaches the retardation plate 23 and is extracted as linearly polarized light vibrating in the same direction as the incident linearly polarized light.

On the other hand, when the TN liquid crystal layer 16 is in the ON state when the second voltage is applied, that is, the right circularly polarized light emitted from the phase difference plate 23 reaches the selective reflection layer 18 while maintaining its rotation direction and is transmitted to the back surface. Is done. Of the light incident from the rear surface of the selective reflection layer 18, the counterclockwise polarized light component seen from the polarizing plate 24 side passes through the selective reflection layer 18 and the TN liquid crystal layer 16, and the polarization of the polarizing plate 24 is It is extracted as linearly polarized light oscillating in the direction perpendicular to the axis.

In this way, the display device having the same configuration can be used for reflection type display using external light (incident light from the polarizing plate side), and
Transmissive display using a rear light source can be performed.

When the retardation plate is disposed so that the slow axis forms an angle of approximately 45 ° counterclockwise from the polarization axis, the twist direction of the cholesteric liquid crystal in the selective diffusion layer 18 is made clockwise to be the same. Operation can be achieved.

As the back light source 25, a surface light source in which a linear light source 25b is arranged on the side surface of a light guide 25a made of a light-transmitting flat plate made of, for example, acrylic can be used. By providing the scattering reflection layer 25c on the back surface of the light guide, the polarization component of the circularly polarized light reflected from the selective reflection layer 18 can be rotated by the selective reflection layer 18 and the scattering reflection layer until the rotation direction is transmitted through the selective reflection layer 18. 25c. Therefore, if the loss due to the absorption of the scattering reflection layer is eliminated, the efficiency of using the light from the linear light source can be extremely increased.

As described above, the reflection / transmission relationship with respect to light incident from the main surface and the rear surface of the selective reflection layer has the same relationship with respect to the rotation direction of the incident circularly polarized light.
Therefore, when the variable retarder modulates the phase of the incident light, a bright display is obtained, and when the phase is not modulated, a dark display is obtained.

Incidentally, as the variable retarder layer 16 of the present embodiment, a layer having a function of shifting the phase of the incident light by λ / 2 according to the applied voltage can be used. In the above case, an example has been given in which switching is performed between a state in which the incident light is not phase-modulated and a state in which the incident light is delayed by λ / 2. May be used.

Next, the operation of the color filter will be described.
When the first color filter layer 21 of the front substrate 11 functions as a reflection type, incident light from the observation side passes through the color filter twice.

The first color filter layer 21 has a spectral characteristic such that light passes through the color filter twice to obtain a desired color density, as in the related art. FIG.
FIG. 5 shows the spectral characteristics when the light passes through the color filter twice. The characteristic shown in FIG. 5 is obtained by squaring the transmittance at each wavelength of the spectral characteristic shown in FIG. As is clear from the figure, it is understood that a sufficient color density is not obtained only by transmitting the color filter once. On the other hand, when the light passes through the color filter twice, a sufficient color density is obtained.

By the way, this liquid crystal display device is
In the case of performing transmissive display using No. 5, the light passes through the first color filter layer 21 only once as described above. Therefore, the bandpass filter 220 is disposed between the selective reflection layer 18 and the back light source, in this embodiment, below the selective reflection layer. FIG. 1 shows an example in which a color absorption filter, specifically, a second color filter 22 in which a pigment is dispersed in an organic medium such as an acrylic resin as in the first color filter is used as the bandpass filter. .

The second color filter layer 22 is formed by a conventional transmission type color filter shown in FIG. 15 when light from the rear surface is transmitted through the second color filter layer 22 and the first color filter layer 21 sequentially. Is designed to have the same spectral characteristics as. Specifically, the spectral characteristic may be a spectral characteristic composed of a value obtained by dividing the transmittance at each wavelength of the spectral characteristics of the conventional transmission type color filter by the transmittance at each wavelength of the spectral characteristics of the first color filter.

FIG. 6 shows the spectral characteristics of the RGB color filters obtained by the pigment dispersion method thus obtained. As described above, when functioning as a transmissive type, the light emitted from the rear light source passes through the second color filter layer 22 and the first color filter layer 21 sequentially, so that the color density of the display is reduced by both color filters. Is obtained. FIG. 7 shows spectral characteristics when the light passes through the second color filter layer 22 and the first color filter layer 21 sequentially. It can be seen that when functioning as a transmission type, a dark color density can be obtained as in the conventional transmission type. By using a selective reflection layer as the selective reflection layer 18, the selective reflection layer does not function as a light shielding layer for light emitted from the back light source 25,
As long as even the polarization components match, all light passes through the selective reflection layer, so that no light loss occurs. In addition, since the selective reflection layer itself functions as a polarizer, there is an effect that one polarizing plate can be omitted.

The same effect can be obtained even if the second color filter 22 is disposed on the outer surface of the rear substrate 13 of the liquid crystal display element as shown in FIG. In this case, in order to reduce the parallax due to the thickness of the substrate, the arrangement of the second color filters may be shifted to form a pattern arrangement centered on a region functioning as a transmission type as shown in the figure.
The production can be simplified by forming the selective reflection layer 18 into a film shape and independently producing and attaching the film.

FIG. 9 shows a configuration in which a selective reflection layer made of a cholesteric liquid crystal polymer is used as the selective reflection layer 18, and the selective reflection layer 18 is also used as a second color filter layer. The same reference numerals as those in FIG. 1 indicate the same parts.

The cholesteric liquid crystal polymer layer used here has a helical pitch that changes continuously within the layer.
Specifically, a pitch cholesteric liquid crystal polymer layer (for example, cholesteric LC silicon manufactured by Wacker Chemical) that selectively reflects light in the ultraviolet region and a pitch cholesteric liquid crystal polymer layer (for example, manufactured by Wacker Chemical) that selectively reflects light in the infrared ultraviolet region. If cholesteric LC silicon is continuously formed, it can be formed by the interaction effect of the interface.

As shown in FIG. 3, such a cholesteric liquid crystal polymer layer separates both light Lf incident from above and light Lb incident from below into right and left circularly polarized light, and transmits and reflects the same. Therefore, if the liquid crystal layer 16 has a λ / 2 phase difference (for example, a configuration in which the liquid crystal layer 16 is twisted by 90 degrees using a nematic liquid crystal), the phase of the circularly polarized light is controlled by controlling the phase difference from 0 to λ / 2. It can be shifted from 0 to λ / 2 and can switch between left and right circularly polarized light. 1 on the front board
A 型 wavelength plate 23 and a polarizing plate 24 are arranged, and as shown in FIG. 9, both in the case of functioning as a reflection type and in the case of functioning as a transmission type, if circularly polarized light is made incident on the liquid crystal layer, the reflection type is obtained. No light loss occurs when functioning or when functioning as a transmissive type.

Further, by using the color filter layer as a layer also serving as the cholesteric liquid crystal polymer layer, the total number of layers can be reduced. Specifically, a dye (RGB) used for ink or the like in the cholesteric liquid crystal polymer layer
May be added.

FIG. 10 shows an example in which an interference filter 221 is used as a band-pass filter. As this interference filter, for example, a filter in which a plurality of dielectrics are alternately laminated is known, and a combination of CeO2 and MgF2 is known as a dielectric to be laminated. By appropriately adjusting the material (refractive index) of such a dielectric multilayer film and the number of layers to be laminated, a desired frequency can be obtained.

FIG. 11 shows the transmittance characteristics of this bandpass filter. As compared with the spectral characteristics of the first color filter shown in FIG. 4, the light transmitted by the bandpass filter has a narrower band. Therefore, when the spectrum of the light source light has, for example, the characteristics as shown in FIG. 12, the light of the wavelength corresponding to the skirt region of the transmitted light of G of the first color filter is cut by the band-pass filter. Therefore, a suitable color density can be obtained.

[0057]

According to the present invention, in a transflective color liquid crystal display device, a bright display with high color density can be obtained regardless of whether it functions as a reflection type or a transmission type.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of one embodiment of the present invention.

FIG. 2 illustrates the operation of an embodiment of the present invention.
(A) is a schematic diagram showing a state when no voltage is applied (Voff), and (b) is a schematic diagram showing a state when voltage is applied (Von).

FIG. 3 is a schematic diagram for explaining the operation of the selective reflection layer according to one embodiment of the present invention;

FIG. 4 is a curve diagram illustrating an example of spectral characteristics of a first color filter according to the embodiment of the present invention;

FIG. 5 is a curve diagram showing an example of a total color filter spectral characteristic when the embodiment of the present invention is caused to function as a reflection type;

FIG. 6 is a curve diagram illustrating an example of spectral characteristics of a second color filter according to the embodiment of the present invention;

FIG. 7 is a curve diagram showing an example of the spectral characteristics of a comprehensive color filter when one embodiment of the present invention is caused to function as a transmission type.

FIG. 8 is a schematic sectional view illustrating another embodiment of the present invention;

FIG. 9 is a schematic sectional view illustrating another embodiment of the present invention;

FIG. 10 is a schematic cross-sectional view illustrating another embodiment of the present invention.

FIG. 11 is a curve diagram showing transmittance characteristics of the bandpass filter according to the embodiment of the present invention;

FIG. 12 is a curve diagram showing one spectrum characteristic of light source light;

FIG. 13 is a schematic cross-sectional view illustrating a conventional transflective color liquid crystal display element.

FIG. 14 is a curve diagram showing an example of spectral characteristics of a color filter of a conventional transflective color liquid crystal display element.

FIG. 15 is a curve diagram showing an example of spectral characteristics of a color filter of a conventional transmission type color liquid crystal display element.

FIG. 16 is a curve diagram showing an example of the overall spectral characteristics of a color filter when a conventional transflective color liquid crystal display element is made to function as a reflection type.

[Explanation of symbols]

 11: front substrate 13: rear substrate 12: counter electrode (liquid crystal drive electrode) 14: pixel electrode (liquid crystal drive electrode) 16: liquid crystal layer 18: selective reflection layer 21: first color filter layer 22: second color filter Layer 23: retardation plate 24: polarizing plate 25: back light source 220: band pass filter

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshinori Higuchi 1-9-2, Hara-cho, Fukaya-shi, Saitama F-term in Fukaya Electronics Factory, Toshiba Corporation (reference) 2H048 BB02 BB10 BB42 2H049 BA03 BA07 BA18 BA24 BA42 BB13 BB66 BC22 2H091 FA01Y FA02Y FA08X FA11X FA14Y FA15Y FB02 FB12 FB13 GA07 GA13 LA16

Claims (11)

[Claims] A front substrate and a rear substrate having liquid crystal driving electrodes formed on respective inner surfaces thereof; and a front substrate and a rear substrate sandwiched between the front substrate and the rear substrate, and a phase of incident light according to an applied voltage. A liquid crystal layer that modulates the light, a retardation plate and a polarizing plate having a polarization axis sequentially placed on the outer surface of one of the substrates, and the first circularly polarized component of incident light formed on the other substrate and reflecting the first circularly polarized light component. A selective reflection layer that transmits a second circularly polarized light component that is opposite to the one circularly polarized light component; a back light source disposed on the back surface of the rear substrate; and a first light source disposed on the front substrate side relative to the selective reflection layer. A liquid crystal display device comprising: a color filter layer; and a band-pass filter disposed closer to the back light source than the selective reflection layer. 2. The liquid crystal according to claim 1, wherein the bandpass filter has a spectral transmittance characteristic in a narrower band than that of the color filter layer in a transmission wavelength region of any one of the color filter layers. Display element. 3. The band-pass filter according to claim 2, wherein the band-pass filter comprises a second color filter in which a plurality of color absorption filter layers each having a different spectral transmittance characteristic are regularly arranged. Liquid crystal display element. 4. The liquid crystal display device according to claim 2, wherein said band pass filter is an interference filter layer. 5. The retardation plate is arranged such that a slow axis of the retardation plate is approximately 45 ° in a predetermined direction from the polarization axis when viewed from the front side of the polarization plate. The liquid crystal display device according to claim 1. 6. The liquid crystal display device according to claim 1, wherein the selective reflection layer is a cholesteric liquid crystal layer. 7. The liquid crystal display device according to claim 6, wherein a swing direction of the cholesteric liquid crystal layer is opposite to a rotation direction from the polarization axis to the slow axis. 8. The liquid crystal display device according to claim 1, wherein the first color filter layer is formed on an inner surface of the front substrate. 9. The liquid crystal display device according to claim 1, wherein the band pass filter is formed on an outer surface of the back substrate. 10. The liquid crystal display device according to claim 1, wherein the band pass filter is laminated below the selective reflection layer. 11. The liquid crystal display device according to claim 1, wherein the second color filter layer is formed by coloring the selective reflection film.