JP2004333999A - Reflection type liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform high-contrast-ratio display by using a reflection type liquid crystal display using cholesteric liquid crystal without lowering the reflectance. <P>SOLUTION: The reflection type liquid crystal display device having a cholesteric liquid crystal interposed between two transparent electrode substrates performs display in a light state through selective wavelength reflection in a planar state, transmits light in a focal conic state and performs display in a dark state through light absorption by a light absorbing layer provided on the back of a liquid crystal panel, and is equipped, on a panel surface, with a member having a function of polarizing light entering a panel into unidirectional circular polarized light. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a reflective liquid crystal display device, in particular, a display in a bright state by selective wavelength reflection in a planar state of a cholesteric liquid crystal, transmission of light in a focal conic state of the cholesteric liquid crystal, and light absorption in a light absorbing layer on the back side thereof. The present invention relates to a reflection type liquid crystal display device which performs display in a dark state by using the same.
[0002]
[Prior art]
It is known that a cholesteric liquid crystal exhibits a spontaneously twisted alignment state, and scatters and reflects light according to one cycle of the twist alignment (helical pitch: P). This phenomenon is called selective wavelength reflection, and reflects light having a wavelength represented by λ = nP (λ: wavelength of reflected light, n: refractive index of liquid crystal). However, of the two types of incident light (clockwise and counterclockwise), only the component that matches the twist direction of the liquid crystal is reflected, and the other polarized light has no effect. Transmit without receiving. Therefore, the reflectance when limited to a specific wavelength is ideally 50%.
[0003]
Although various proposals have been made so far for a display device using cholesteric liquid crystal, the present invention is directed to a reflection type display device utilizing a difference in reflection characteristics between a planar state and a focal conic state of cholesteric liquid crystal. Has the advantage that the configuration is very simple. This configuration and operation principle will be described with reference to FIG.
[0004]
A display device using cholesteric liquid crystal has a very simple panel configuration in which a cholesteric liquid crystal 3 is sandwiched between glass substrates 1a and 1b provided with two transparent electrodes 2a and 2b, and an alignment film is formed on the transparent electrode. Whether to use it or not and whether or not to perform an alignment treatment such as a rubbing treatment when using an alignment film largely depend on driving conditions and liquid crystal characteristics, and cannot be uniquely determined. However, in order to obtain the following two kinds of stable alignment states, some processing for aligning liquid crystal molecules in parallel with the transparent electrode surface is generally used.
[0005]
When a sufficiently high voltage is applied to the liquid crystal layer, the liquid crystal is in homeotropic alignment, and when the voltage is stopped, the liquid crystal is in a planar alignment state (FIG. 5A). In this planar alignment state, the above-mentioned selective wavelength reflection 6 is shown, and it is observed as a lighting state (display of a bright state) of a color corresponding to the helical pitch of the cholesteric liquid crystal. At this time, the reflected light is only a circularly polarized component in the same direction as the helix of the cholesteric liquid crystal. Thereafter, when a pulsed electric field of an appropriate voltage is applied, a focal conic alignment state (FIG. 5B) is obtained after the application of the voltage is stopped. In this focal conic alignment state, reflection at the selected wavelength does not occur, and the incident light is transmitted as it is. If a light absorbing layer 4 is provided on the back surface of the liquid crystal panel, the transmitted light is absorbed and observed as a black display (display in a dark state).
[0006]
By adjusting the voltage for obtaining this black display, the coexistence ratio between the planar state and the focal conic state can be changed, and halftone display is also possible. Further, regarding colorization, it is possible to create three panels using a cholesteric liquid crystal material having a helical pitch whose selected wavelength corresponds to each of R, G, and B, and to superimpose them (for example, Patent Document 1).
[0007]
The display device using the selected wavelength reflection of the cholesteric liquid crystal can perform display according to the above principle, and can obtain a high reflectance of 50% in principle. In a color reflective display using a normal polarizing plate and a color filter, the reflectivity of the liquid crystal itself does not greatly change to 40%, but the reflectivity is further reduced by 1 / R because the R, G, and B portions are distributed in a plane. It is generally 3 or less, and the substantial reflectance is generally less than 10%. Therefore, in the display device using the selective wavelength reflection of the cholesteric liquid crystal, a very high reflectance several times higher than that of the display device using the polarizing plate and the color filter can be obtained, and a very good reflective display can be obtained. be able to.
[0008]
[Non-patent document 1]
Supervised by Tatsuo Uchida, "Reflective Color LCD Comprehensive Technology", CMC, 1999, p. 138-143
[0009]
[Problems to be solved by the invention]
However, a display device using this cholesteric liquid crystal and utilizing a difference in reflection characteristics between two states has a problem that the contrast ratio is low. This is due to the fact that in the focal conic alignment state, the liquid crystal is separately aligned for each minute region, so that the incident light is not transmitted without any influence and is slightly scattered. That is, since the backscattering component 7 due to the presence of the plurality of minute regions returns to the viewer side from the liquid crystal panel, the light-absorbing layer is observed slightly whiter than the black state.
[0010]
In an actually manufactured cholesteric liquid crystal panel, the contrast ratio, which is the ratio of the reflectance in the planar state to the reflectance in the focal conic state, is about 10 or less, and a sharp display cannot be obtained.
[0011]
In the present invention, a backscattering component in the focal conic state (black display state) is reduced, and a display with a high contrast ratio is achieved without lowering the reflectance in the planar state (white display state or bright state display). The purpose is to achieve.
[0012]
[Means for Solving the Problems]
The present invention is to achieve the above object,
A liquid crystal display panel in which a cholesteric liquid crystal is sandwiched between substrates having two transparent electrodes; and a light absorbing layer disposed on the back side of the liquid crystal display panel. In a reflection type liquid crystal display device which performs state display and displays a dark state by transmitting light in the focal conic state of the cholesteric liquid crystal and absorbing light in the light absorbing layer, light incident on the liquid crystal display panel is A member having a function of making circular polarization in one direction is provided on the front surface of the liquid crystal display panel.
[0013]
Further, another liquid crystal display device of the present invention,
A plurality of liquid crystal display panels and a light absorbing layer in which a cholesteric liquid crystal is sandwiched between substrates having two transparent electrodes; and the plurality of liquid crystal display panels are stacked and arranged on each other. The cholesteric liquid crystal is disposed on the back side of the cholesteric liquid crystal to display a bright state by reflection of a selected wavelength in a planar state, and the cholesteric liquid crystal transmits light in a focal conic state and transmits light in the light absorbing layer. A reflection type liquid crystal display device that performs display in a dark state by light absorption, wherein a member having a function of converting incident light incident on the plurality of liquid crystal display panels into circularly polarized light in one direction is used for any of the plurality of liquid crystal displays It is characterized by being provided on the forefront than the panel.
[0014]
Further, still another reflection type liquid crystal display device of the present invention,
A plurality of liquid crystal display panels and a light absorbing layer in which a cholesteric liquid crystal is sandwiched between substrates having two transparent electrodes; and the plurality of liquid crystal display panels are stacked and arranged on each other. The cholesteric liquid crystal is disposed on the back side of the cholesteric liquid crystal to display a bright state by reflection of a selected wavelength in a planar state, and the cholesteric liquid crystal transmits light in a focal conic state and transmits light in the light absorbing layer. A reflection type liquid crystal display device that performs display in a dark state by light absorption, wherein a member having a function of converting incident light incident on the plurality of liquid crystal display panels into circular polarization in one direction is included in the plurality of liquid crystal display panels. It is characterized by being prepared in between.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
In the reflection type liquid crystal display device using the cholesteric liquid crystal of the present invention, as shown in FIG. 1, a member having a function of converting transmitted light into one-directional circularly polarized light is provided on the front surface (observer side) of the cholesteric liquid crystal display panel. 12 (hereinafter, referred to as “circular polarizing plate”). As a specific example of the circularly polarizing plate 12, a retardation film (hereinafter, referred to as a "1 / 4.lambda. Film") 11 having a retardation value of 1 / 4.lamda. Is attached, and the polarizing plate 10 is further attached thereon.
[0016]
FIG. 2 shows the relationship between the transmission axis of the polarizing plate 10 and the angle of the stretching axis of the λλ film 11. The reference direction is the x-axis in FIG. 2 (the direction parallel to the long side of the panel), the angle between the transmission axis of the polarizing plate and the reference axis is α, and the angle between the stretching axis of the λλ film and the reference axis. Is β. In FIG. 2, although α> β, the magnitude relationship between α and β is such that, as described in the embodiment, linearly polarized light transmitted through the polarizing plate is in the same direction as the direction of the helical structure of the liquid crystal by the １ ／ λ film. Is set to be circularly polarized light.
[0017]
In FIG. 1, if the liquid crystal in the cholesteric liquid crystal panel is in a planar state, basically all incident light is reflected (FIG. 1 (a)).
[0018]
In general, circularly polarized light reflected by a mirror surface cannot be transmitted through a polarizing plate because it becomes linearly polarized light rotated by 90 ° from that at the time of incidence when transmitted again through a λλ film, but is reflected by the selected wavelength reflection of cholesteric liquid crystal. The circularly polarized light is a circularly polarized light in the same direction as that at the time of incidence unlike the case where the light is reflected by a mirror surface, and further becomes a linearly polarized light in the same direction as that at the time of incidence by the ４λ film 11, so that it can pass through the polarizing plate 10. .
[0019]
By using the polarizing plate 10, 50% of the light is absorbed there and the light use efficiency is reduced. However, as described in the related art, the light reflected during white display is only a polarized light component in one direction, and the other component is transmitted as it is and is absorbed by the light absorbing layer 4 on the back surface. Therefore, the white display mode in this planar state is the same in that only one-way circularly polarized light component is used for display, with or without the use of a polarizing plate. Usage efficiency does not decrease.
[0020]
Next, the reflectance in the focal conic state (a black display state in which incident light is transmitted and absorbed by the light absorbing layer) will be described.
[0021]
It has already been mentioned that the backscattering component in the focal conic state causes an increase in the black luminance, thereby reducing the contrast ratio. The magnitude of this backscattering component has no relation to the polarization direction. In other words, in the focal conic state, the liquid crystal is in a state of being separately aligned for each small area, and backscattering is caused by the presence of the minute area. Therefore, both types of light (clockwise and counterclockwise) are polarized. reflect.
[0022]
In the case of the reflection type liquid crystal display device of the present invention using the polarizing plate 10 and the ４λ film 11, since the polarization state is already in one direction at the incident stage, only the polarization in one direction is naturally backscattered even in the focal conic state. Does not cause reflection due to Therefore, the luminance at the time of black display can be reduced to half of that of the conventional display device (FIG. 1B).
[0023]
To summarize the above points, in the conventional display device, white display = reflects all polarized light in one direction, and black display = reflects the back-scattered component of polarized light in both directions. Display = reflects all polarized light in one direction, black display = reflects backscattered component of polarized light in one direction. In other words, by removing, from the beginning, the polarization component of the incident light that cannot be finally used as the reflected light by the circularly polarizing plate 12, the backscattering is reduced by half without reducing the reflectance in white display. Can be reduced.
[0024]
Therefore, as in the present invention, the circularly polarizing plate 12 (for example, the polarizing plate 10 and the １ ／ λ film 11 are formed on the surface of the cholesteric liquid crystal display panel utilizing the difference in the reflection characteristics between the planar state and the focal conic state). (Attached at an appropriate angle) so that the circularly polarizing plate 12 transmits reflected light substantially as it is in white display, and only one-directional polarized light of backscattered light in black display. Is transmitted, so that the contrast ratio can be almost doubled without lowering the reflectivity during white display.
[0025]
Cholesteric liquid crystals have different selective reflection wavelengths depending on their helical pitch, so to fully utilize the functions of the present invention, use a circularly polarizing plate that converts light of a selectively reflected wavelength into unidirectional circularly polarized light. Is preferred. Specifically, by adjusting the angle (α-β) between the absorption axis of the polarizing plate 10 and the stretching axis of the retardation film 11 thereunder, and adjusting the retardation value of the retardation film 11, the desired wavelength can be obtained. Need to be adjusted to convert the light into circularly polarized light. However, by adjusting so that light having a wavelength of about 550 nm, which is substantially at the center of the visible light region, is converted into circularly polarized light, the effect of sufficiently increasing the contrast ratio can be exerted in the almost entire visible light range.
[0026]
Hereinafter, embodiments of the present invention will be described in more detail with reference to Examples and Comparative Examples.
[0027]
Comparative Example 1
A liquid crystal material having the following characteristics was prepared.
Dielectric anisotropy: about 7, average refractive index: about 1.52, helical pitch: about 0.36 μm (left-handed)
[0028]
At this time, the selected wavelength reflection occurs in the vicinity of λ = 1.52 × 0.36 μm = about 550 nm.
[0029]
This cholesteric liquid crystal material was sandwiched between two transparent electrode substrates to form a liquid crystal panel. The cell gap was about 5 μm.
[0030]
Black paper was stuck to the back of the panel as a light absorbing layer, and nearly parallel light from a xenon light source was incident from a direction 30 degrees from the vertical direction of the front of the panel, and the reflection luminance in the vertical direction was measured. The reflectance was determined by measuring the reflection luminance of a barium sulfate standard white plate by the same method, and determining the reflectance.
[0031]
When a bipolar (alternating current) pulse (reset pulse) having an amplitude of ± 50 V and a pulse width of 50 ms was applied between the two transparent electrodes, homeotropic alignment was achieved only while the pulse was being applied, and then a stable planar state was achieved. In this state, the reflectance of light having a wavelength of 550 nm was about 40%. When a bipolar (AC) pulse (black writing pulse) having an amplitude of ± 28 V and a pulse width of 10 ms was applied after the application of the reset pulse, a stable focal conic state was obtained. In this state, the reflectance of light having a wavelength of 550 nm was 5.5%, and the contrast ratio was about 7.
[0032]
Example 1
The same cholesteric liquid crystal panel as in Comparative Example 1 was produced.
[0033]
A retardation film made of a stretched polycarbonate film was attached to the surface of this panel. The retardation of the retardation film was 140 nm with respect to light having a wavelength of 550 nm, and the stretching axis was attached in parallel to the edge of the panel. (The sticking angle is important for the relative angle (α-β) to the polarizing plate to be stuck thereon, and the direction of the stretching axis with respect to the panel is completely arbitrary.)
[0034]
Next, a polarizing plate was stuck on this retardation film. The sticking angle of the polarizing plate was such that the transmission axis was rotated clockwise by 45 degrees with respect to the stretching axis of the retardation film (β-α = 45 °).
[0035]
At this time, light transmitted through the polarizing plate and further transmitted through the retardation film becomes counterclockwise circularly polarized light.
[0036]
When the same reset pulse as in Comparative Example 1 was applied, the liquid crystal alignment in the panel was in a planar state, and the reflectance of light having a wavelength of 550 nm at that time was about 34%.
Next, when a black writing pulse similar to that of Comparative Example 1 was applied, a stable focal conic state was obtained, and the reflectance was about 2.5% and the contrast ratio was about 13.
[0037]
According to this method, the reflectance in the planar state slightly decreases (in the case of the present embodiment, a reduction rate of about 20%), but the contrast ratio which is a problem in the reflection type liquid crystal display device using the cholesteric liquid crystal is about twice. And a good display with high contrast was obtained.
[0038]
Example 2
Using the same liquid crystal material as in Example 1, the helical pitch was adjusted to 0.3 μm in a clockwise direction, and the liquid crystal was injected into the same liquid crystal panel as in Example 1 to obtain a cholesteric liquid crystal panel.
A light absorbing layer was attached to the back of this panel, and the reflection luminance was evaluated in the same manner as in Example 1.
[0039]
A retardation film having a retardation of 140 nm for light having a wavelength of 550 nm and a polarizing plate were attached to the front surface of the panel. The transmission axis of the polarizing plate was rotated counterclockwise by 45 degrees with respect to the stretching axis of the retardation film (α-β = 45 °). The light transmitted through the polarizing plate and the retardation film becomes clockwise circularly polarized light.
[0040]
When a reset pulse having an amplitude of ± 50 V and a pulse width of 50 ms was applied between the two transparent electrodes, the liquid crystal layer was brought into a stable planar state and reflected light having a wavelength of about 450 nm. The reflectance is about 35% with respect to light having a wavelength of 450 nm. When a black writing pulse with an amplitude of ± 30 V and a pulse width of 10 ms is applied, a stable focal conic state is obtained. The reflectance is about 3% and a contrast ratio of about 12 is obtained. Was completed.
[0041]
Comparative Example 2
When the same cholesteric liquid crystal panel as in Example 2 was used and the front surface was driven without using a retardation film and a polarizing plate, the reflectance for light having a wavelength of 450 nm was about 40% in the planar state, and in the focal conic state. Was about 6%, and the contrast ratio was about 7, indicating that a sufficient contrast ratio could not be obtained.
[0042]
Example 3
The helical pitch was adjusted to 0.30 μm, 0.36 μm, and 0.43 μm (all counterclockwise) using the same liquid crystal material as in Example 1. These three cholesteric liquid crystal compositions exhibit selective wavelength reflection for light having a wavelength of about 450 nm, about 550 nm, and about 650 nm, respectively.
[0043]
These three cholesteric liquid crystal compositions were injected into three transparent electrode cells similar to those in Example 1. Hereinafter, a panel using 0.3 μm pitch liquid crystal is referred to as “panel 1”, a panel using 0.36 μm pitch liquid crystal is referred to as “panel 2”, and a panel using 0.43 μm pitch liquid crystal is referred to as “panel 3”. . By laminating these three types of panels 1 to 3 as shown in FIG. 3 and driving them independently, color display can be performed. Note that the order of lamination was panel 1, panel 2, panel 3, and the light absorbing layer from the top (observer side). Even if the order is different, color display is possible, but in order to reduce the influence of scattering by the panel stacked on top, a panel that selectively reflects short-wavelength light is set on the top, and the bottom (light absorption layer side) It is better to provide a panel that selectively reflects long-wavelength light in terms of contrast ratio.
[0044]
As shown in FIG. 3, the same polarizer as in Example 1 and a circular polarizer 12 composed of a １ ／ λ film were attached to the forefront of the superposed panels. The transmission axis of the polarizing plate was rotated clockwise by 45 degrees (β−α = 45 °) with respect to the stretching axis of the ４λ film, as in Example 1.
[0045]
The driving conditions for each panel were the same as in Example 1.
[0046]
The reflectance and contrast ratio of the panel thus prepared were measured using white light from a xenon lamp light source. The reflectivity during white display (panel 1 to 3 in the planar state) is about 28%, and the contrast ratio (reflectance ratio in the planar state in all of the panels 1 to 3 in the focal conic state) is: 13 was good.
[0047]
Example 4
Three types of cholesteric liquid crystal panels were prepared in the same manner as in Example 3, and the respective panels were laminated as shown in FIG.
[0048]
In this example, the circularly polarizing plate 12 was placed in front of the red (panel 3) (that is, between the panels 2 and 3) close to the light absorbing layer (FIG. 4). The circularly polarizing plate used was composed of a polarizing plate and a λλ film as in Example 3, and the transmission axis of the polarizing plate was rotated clockwise by 45 ° with respect to the stretching axis of the λλ film. (Β−α = 45 °).
[0049]
According to the method of the present invention, the contrast ratio can be approximately doubled without substantially lowering the reflectance. However, when a circularly polarizing plate is installed on the frontmost surface where three panels are superimposed, the effect of increasing the contrast ratio remains unchanged as compared with the case where only one panel is used and the circularly polarizing plate is used on the surface. , The reflectivity slightly decreases. Therefore, by using a circularly polarizing plate between the second and third sheets from the front surface instead of the frontmost one, the effect of increasing the contrast ratio affects only the rearmost one panel, but the reflectivity is almost the same. Does not drop.
[0050]
In the reflective type color liquid crystal display device having this structure, the reflectance and the contrast ratio were measured in the same manner as in Example 3. As a result, good characteristics of a reflectance of 32% and a contrast ratio of about 10 were obtained.
[0051]
In this embodiment, an example is shown in which a circularly polarizing plate is placed between the second and third sheets. However, even when a circularly polarizing plate is placed between the first and second sheets, a high A display with high reflectance and high contrast ratio can be obtained.
[0052]
【The invention's effect】
According to the reflective cholesteric liquid crystal display device of the present invention, by providing the circularly polarizing plate on the front surface of the liquid crystal display panel, the circularly polarizing plate transmits reflected light substantially as it is when displaying white, and displays black. In the case of, only the polarized light in one direction is transmitted, so that the reflectance in black display is reduced without substantially lowering the reflectance in white display. As a result, the contrast ratio can be almost doubled. As a result, a reflective cholesteric liquid crystal display device having very good display quality can be obtained.
[0053]
Further, in a reflective liquid crystal display device colored by a laminated structure of a plurality of liquid crystal display panels, by providing a circularly polarizing plate on the forefront or between any of the panels, the circularly polarizing plate can be used for white display. Transmits the reflected light substantially as it is, and transmits only polarized light in one direction in the case of black display, so that the reflectance in the black display is reduced with almost no decrease in the reflectance in the white display As a result, the contrast ratio can be almost doubled, and a color reflection type cholesteric liquid crystal display device having very good display quality can be obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view schematically showing a reflection type liquid crystal display device using a cholesteric liquid crystal of the present invention.
FIG. 2 is a perspective view illustrating directions of a transmission axis of a polarizing plate and a stretching axis of a retardation plate.
FIG. 3 is a schematic diagram illustrating an example of a liquid crystal display device including a plurality of panels according to the present invention.
FIG. 4 is a schematic diagram showing another example of a liquid crystal display device including a plurality of panels according to the present invention.
FIG. 5 is a sectional view schematically showing a conventional reflection type liquid crystal display device using cholesteric liquid crystal.
[Explanation of symbols]
1a, 1b glass substrate, 2a, 2b transparent electrode, 3 cholesteric liquid crystal, 4 light absorbing layer, 5 incident light from outside, 6 reflected light in white display, 7 reflected light in black display, 8 transmission in white display Light, 9 Transmitted light for black display, 10 Polarizer, 11 Phase difference plate, 12 Circular polarizer, 13 Panel 1, 14 Panel 2, 15 Panel 3.

Claims (8)

A liquid crystal display panel in which a cholesteric liquid crystal is sandwiched between substrates having two transparent electrodes; and a light absorbing layer disposed on the back side of the liquid crystal display panel. In a reflection type liquid crystal display device which performs state display and performs dark state display by transmitting light in the focal conic state of the cholesteric liquid crystal and absorbing light in the light absorbing layer, light incident on the liquid crystal display panel is A reflection type liquid crystal display device, wherein a member having a function of converting circular polarization in one direction is provided on a front surface of the liquid crystal display panel. A member for converting light incident on the liquid crystal display panel into circularly polarized light in one direction includes a polarizing plate disposed on the viewer side, and approximately 1 / 4λ disposed between the polarizing plate and the liquid crystal display panel. 2. The reflective liquid crystal display device according to claim 1, further comprising a retardation film having a corresponding retardation value. 3. The reflection type liquid crystal display device according to claim 1, wherein the helical direction of the cholesteric liquid crystal in the liquid crystal display panel and the direction of the circularly polarized light incident on the liquid crystal display panel are matched. A plurality of liquid crystal display panels and a light absorbing layer in which a cholesteric liquid crystal is sandwiched between substrates having two transparent electrodes are provided, and the plurality of liquid crystal display panels are stacked on each other, and the light absorbing layer is The cholesteric liquid crystal is disposed on the back side of any of the plurality of liquid crystal display panels, performs display in a bright state by selective wavelength reflection in the planar state of the cholesteric liquid crystal, and transmits light in the focal conic state of the cholesteric liquid crystal and the light absorbing layer. A reflection type liquid crystal display device that performs display in a dark state by light absorption of the liquid crystal display device, the member having a function of converting incident light incident on the plurality of liquid crystal display panels into one-way circularly polarized light. A reflective liquid crystal display device, which is provided at the forefront of a display panel. A plurality of liquid crystal display panels and a light absorbing layer in which a cholesteric liquid crystal is sandwiched between substrates having two transparent electrodes are provided, and the plurality of liquid crystal display panels are stacked on each other, and the light absorbing layer is The cholesteric liquid crystal is disposed on the back side of any of the plurality of liquid crystal display panels, performs display in a bright state by selective wavelength reflection in the planar state of the cholesteric liquid crystal, and transmits light in the focal conic state of the cholesteric liquid crystal and the light absorbing layer. A reflective liquid crystal display device that performs display in a dark state by light absorption of the plurality of liquid crystal display panels, the member having a function of converting incident light incident on the plurality of liquid crystal display panels into one-way circularly polarized light. A reflection-type liquid crystal display device, which is provided between the above. 6. The reflective liquid crystal display device according to claim 4, wherein each of the cholesteric liquid crystals injected into the plurality of liquid crystal display panels has a different helical pitch. A member having a function of converting incident light entering the liquid crystal display panel into circularly polarized light in one direction includes a polarizing plate disposed on the viewer side, and a polarizing plate disposed between the polarizing plate and the liquid crystal display panel. 7. The reflection type liquid crystal display device according to claim 4, further comprising a retardation film having a retardation value substantially equivalent to / 4λ. 6. The reflection type liquid crystal display device according to claim 4, wherein the helical direction of the cholesteric liquid crystal in the liquid crystal display panel and the direction of the circularly polarized light to be incident on the liquid crystal display panel are matched.

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