JP7491163B2 - Reflective liquid crystal display element and liquid crystal display device - Google Patents

Description

The present invention relates to a reflective liquid crystal display element and a liquid crystal display device.

There is a technology that provides a laminated structure on the inner surface of a transparent substrate, which consists of a transparent electrode layer, an alignment layer, and one or more transparent intermediate layers that have a refractive index smaller than that of the transparent electrode layer and greater than that of the liquid crystal layer or the transparent substrate (see, for example, Patent Document 1). As a result, the intermediate layers suppress the reflection of light that passes through the transparent electrode.

Japanese Patent Application Laid-Open No. 11-174427

However, the intermediate layer alone is insufficient in suppressing the reflection of light passing through the transparent electrode.

The present invention has been made in view of the above, and provides a reflective liquid crystal display element and a liquid crystal display device that can sufficiently suppress the reflection of light that passes through a transparent electrode.

In order to solve the above-mentioned problems and achieve the object, the reflective liquid crystal display element of the present invention is a reflective liquid crystal display element that reflects incident light, and includes a flat first member, a flat second member that is disposed opposite the first member in the stacking direction and has a different refractive index from the first member, and an intermediate layer that is disposed between the first member and the second member in the stacking direction and has a first intermediate member and a second intermediate member that is in contact with the first intermediate member on the second member side of the first intermediate member, the first intermediate member includes a first microstructure whose unevenness pitch in a planar direction intersecting with the stacking direction is equal to or less than the wavelength of light and whose refractive index of light is made of the same material as that of the first member, and the second intermediate member includes a second microstructure whose unevenness pitch in a planar direction intersecting with the stacking direction is equal to or less than the wavelength of light and whose refractive index of light is made of the same material as that of the second member.

The liquid crystal display device according to the present invention is equipped with a reflective liquid crystal display element.

The present invention has the effect of sufficiently suppressing the reflection of light passing through the transparent electrode.

FIG. 1 is a schematic diagram showing a liquid crystal display device according to an embodiment. FIG. 2 is a vertical cross-sectional view showing a reflective liquid crystal display element according to an embodiment of the present invention. FIG. 3 is a vertical cross-sectional view showing a first microstructure according to the embodiment. FIG. 4 is a vertical cross-sectional view showing a second microstructure according to the embodiment. FIG. 5 is a graph showing the correlation between the thickness and reflectance of the intermediate layer according to the embodiment. FIG. 6 is a vertical cross-sectional view showing a reflective liquid crystal display device according to a modified example of the embodiment.

Embodiments of a reflective liquid crystal display device according to the present invention are described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiments.

[Embodiment]
<Overall Configuration of Liquid Crystal Display Device>
Fig. 1 is a schematic diagram showing a liquid crystal display device 100 according to an embodiment. As shown in Fig. 1, the liquid crystal display device 100 is a projection type image display device that projects an image, more specifically, a moving image, onto a screen S. The liquid crystal display device 100 includes a light emitting device 10, an illumination optical system 12, liquid crystal panels 14b, 14g, and 14r each having a reflective liquid crystal display element, a synthesis optical system 16, and a projection optical system 18.

The light emitting device 10 has a light source that generates light, and irradiates the light generated from the light source as incident light L0 to the illumination optical system 12. In the embodiment, the light emitting device 10 is conveniently illustrated as having one light source in the example of FIG. 1, but may have other optical devices for generating the incident light L0.

The illumination optical system 12 separates the incident light L0 from the light emitting device 10 into a first colored light Lb, a second colored light Lg, and a third colored light Lr. In the embodiment, the first colored light Lb, the second colored light Lg, and the third colored light Lr are each a monochromatic component of the three colored lights that make up the illumination light. Specifically, the first colored light Lb is blue light, the second colored light Lg is green light, and the third colored light Lr is red light. When the first colored light Lb, the second colored light Lg, and the third colored light Lr are not differentiated, they are referred to as incident light L1.

The illumination optical system 12 has optical elements 22, 23, and 24. The optical element 22 separates the incident light L0 from the light emitting device 10 into a first color light Lb and a mixed color light Lgr. The optical element 22 supplies the separated first color light Lb to the optical element 23. The optical element 23 reflects the first color light Lb from the optical element 22 and supplies it to the liquid crystal panel 14b. Here, the mixed color light Lgr is a color light containing color components of the second color light Lg and the third color light Lr. The optical element 22 supplies the separated mixed color light Lgr to the optical element 24. The optical element 24 separates the mixed color light Lgr from the optical element 22 into the second color light Lg and the third color light Lr. The optical element 24 supplies the separated second color light Lg to the liquid crystal panel 14g, and supplies the separated third color light Lr to the liquid crystal panel 14r. Note that the configuration of the illumination optical system 12 shown in FIG. 1 is an example. The illumination optical system 12 may be configured to supply the first color light Lb, the second color light Lg, and the third color light Lr to the liquid crystal panels 14b, 14g, and 14r, respectively.

The liquid crystal panel 14b is a liquid crystal panel that modulates the first color light Lb from the optical element 23 using a liquid crystal element and outputs the modulated first color light Lb as output light Lb2. The liquid crystal panel 14g is a liquid crystal panel that modulates the second color light Lg from the optical element 24 using a liquid crystal element and outputs the modulated second color light Lg as output light Lg2. The liquid crystal panel 14r is a liquid crystal panel that modulates the third color light Lr from the optical element 24 using a liquid crystal element and outputs the modulated third color light Lr as output light Lr2. Hereinafter, when the liquid crystal panels 14b, 14g, and 14r are not differentiated, they will be referred to as liquid crystal panel 14. When the output light Lb2, Lg2, and Lr2 are not differentiated, they will be referred to as output light L2.

The liquid crystal panel 14 is a reflective liquid crystal panel, and more specifically, an LCOS (Liquid Crystal on Silicon). In the embodiment, the liquid crystal panels 14b, 14g, and 14r emit monochromatic emitted light L2 (either emitted light Lb2, emitted light Lg2, or emitted light Lr2). However, the liquid crystal panel 14 may emit an emitted light that is a combination of the color components of the emitted light Lb2, emitted light Lg2, and emitted light Lr2 in a single panel. Each of these liquid crystal panels 14 includes a reflective liquid crystal display element 1.

Returning to FIG. 1, the combining optical system 16 combines the light Lb2 emitted from the liquid crystal panel 14b, the light Lg2 emitted from the liquid crystal panel 14g, and the light Lr2 emitted from the liquid crystal panel 14r to generate a combined light. In the embodiment, the combining optical system 16 includes a cross dichroic prism.

As shown in FIG. 1, the projection optical system 18 receives the composite light generated by the composite optical system 16 and projects the composite light onto the screen S as an image.

The control unit 20 as a control device is a device having a calculation device, i.e., a CPU (Central Processing Unit). The control unit 20 controls the incidence of the incident light L1 on the liquid crystal panel 14. In the embodiment, the control unit 20 controls the incident light L0 from the light emitting device 10 to the illumination optical system 12, thereby switching the incidence of the incident light L1 on the liquid crystal panel 14 on and off. However, the control unit 20 may control the incidence of the incident light L1 on the liquid crystal panel 14, for example, by driving a shutter that blocks the incidence of the incident light L1 on the liquid crystal panel 14, without directly controlling the light emitting device 10.

<Structure of Reflective Liquid Crystal Display Element 1>
FIG. 2 is a vertical cross-sectional view showing a reflective liquid crystal display element 1 according to an embodiment. FIG. 2 illustrates the configuration of the liquid crystal panel 14b, but the liquid crystal panels 14g and 14r have the same configuration. In the following example, a case is described in which the first color light Lb is incident on the liquid crystal panel 14b as incident light and the outgoing light Lb2 is emitted as outgoing light. In the case of the liquid crystal panel 14g, the incident light can be rephrased as the second color light Lg and the outgoing light can be rephrased as the outgoing light Lg2, and in the case of the liquid crystal panel 14b, the incident light can be rephrased as the third color light Lr and the outgoing light can be rephrased as the outgoing light Lr2. As shown in FIG. 2, the liquid crystal panel 14b includes a glass substrate 2, a transparent electrode 3 as a first member, an intermediate layer 4, an alignment film 5 as a second member, a liquid crystal layer 6, an alignment film 7, a reflective electrode 8, and a semiconductor drive substrate 9 made of silicon or the like, which are stacked along the stacking direction Z as a plurality of reflective liquid crystal display elements 1.

The glass substrate 2 is disposed opposite the semiconductor drive substrate 9. The glass substrate 2 is disposed on the side of the semiconductor drive substrate 9 where the first color light Lb is incident as incident light. The glass substrate 2 is formed of a material that transmits light in the stacking direction Z.

A voltage is applied between the transparent electrode 3 and the reflective electrode 8. The transparent electrode 3 is formed in a flat plate shape with flat front and back surfaces. The transparent electrode 3 is provided on the surface of the glass substrate 2 on the semiconductor drive substrate 9 side in the stacking direction Z. The transparent electrode 3 faces a plurality of reflective electrodes 8 in the stacking direction Z. The transparent electrode 3 is formed of a conductive material that can transmit the incident light L1, such as indium tin oxide (ITO) or indium zinc oxide (IZO). In this embodiment, "flat" refers to a surface flatness of 1 μm or less, for example, and the same applies hereinafter.

The reflective electrode 8 is provided on the surface of the semiconductor drive substrate 9 facing the glass substrate 2 in the stacking direction Z. A plurality of reflective electrodes 8 are provided on the surface of the semiconductor drive substrate 9, and are arranged in a two-dimensional matrix. The reflective electrode 8 is an electrode to which a voltage is applied between the transparent electrode 3 under the control of a control unit (not shown). In other words, one reflective electrode 8 constitutes one pixel. In addition to functioning as a pixel electrode, the reflective electrode 8 also serves as a reflective electrode that reflects the first color light Lb. The reflective electrode 8 is made of a material capable of reflecting light, such as aluminum or silver.

The liquid crystal layer 6 is a space provided between the glass substrate 2 and the semiconductor drive substrate 9 in the stacking direction Z, and a liquid crystal element (not shown) is enclosed inside. The liquid crystal element is oriented in one direction when no voltage is applied between the reflective electrode 8 and the transparent electrode 3. Here, when no voltage is applied between the reflective electrode 8 and the transparent electrode 3, the liquid crystal element is oriented in the Z direction, which is the vertical direction of the paper. The Z direction is the direction in which the glass substrate 2 and the semiconductor drive substrate 9 are stacked. When a voltage is applied between the reflective electrode 8 and the transparent electrode 3, the liquid crystal element changes its orientation direction due to the electric field generated by the reflective electrode 8 and the transparent electrode 3. Here, the applied voltage is a constant value. Therefore, when a voltage is applied between the reflective electrode 8 and the transparent electrode 3, the liquid crystal element is oriented in the horizontal direction of the paper, which is a direction perpendicular to the Z direction. However, the orientation direction of the liquid crystal element is not limited to this.

When no voltage is applied between the reflective electrode 8 and the transparent electrode 3, the liquid crystal element is oriented so that the polarization state of the incident first color light Lb does not change. In this case, even if the first color light Lb is incident on the liquid crystal panel 14b, the first color light Lb is blocked by a polarization separation means (not shown) and is not emitted in the direction of the synthesis optical system 16. Therefore, when no voltage is applied between the reflective electrode 8 and the transparent electrode 3, the liquid crystal panel 14b does not emit the outgoing light Lb2. When all the liquid crystal panels 14b, 14g, and 14r do not emit the outgoing light Lb2, the screen is displayed black.

On the other hand, when a voltage is applied between the reflective electrode 8 and the transparent electrode 3, the liquid crystal element is oriented so that the polarization state of the incident first color light Lb changes. The first color light Lb incident on the liquid crystal panel 14b passes through the liquid crystal layer 6 and reaches the reflective electrode 8. The first color light Lb that reaches the reflective electrode 8 is reflected by the reflective electrode 8, passes through the liquid crystal layer 6 again, and is emitted as the outgoing light Lb2. When a voltage is applied between the reflective electrode 8 and the transparent electrode 3 of the liquid crystal panel 14b, the polarization state of the outgoing light Lb2 has been changed by the liquid crystal to which the voltage has been applied, so that the outgoing light Lb2 is emitted in the direction of the synthesis optical system 16 by the polarization separation means (not shown), and the screen displays white.

The alignment film 5 is a plate-like member arranged opposite the transparent electrode 3 in the stacking direction Z. The alignment film 5 is formed in a flat plate shape with flat front and back surfaces. The alignment film 5 has a refractive index of the first color light Lb different from that of the transparent electrode 3. The alignment film 5 is arranged parallel to the transparent electrode 3. The alignment film 5 controls the alignment of the liquid crystal elements when it is necessary for the liquid crystal elements to be aligned in one direction over a certain area. The alignment film 7 has a similar configuration to the alignment film 5.

The intermediate layer 4 is disposed between the transparent electrode 3 and the alignment film 5 in the stacking direction Z. In this embodiment, the intermediate layer 4 is made of an insulator. The intermediate layer 4 transmits the first color light Lb.

The intermediate layer 4 includes a first intermediate member 4a and a second intermediate member 4b. The first intermediate member 4a is provided so as to contact the transparent electrode 3 as the first member. The second intermediate member 4b is disposed closer to the alignment film 5 than the first intermediate member 4a in the stacking direction Z, and is provided so as to contact the alignment film 5 as the second member. The second intermediate member 4b is provided so as to also contact the first intermediate member 4a.

The first intermediate member 4a is made of a material having the same refractive index of the first color light Lb as the transparent electrode 3 as the first member. The material constituting the first intermediate member 4a may be, for example, silicon nitride (Si ₃ N ₄ ). In the embodiment, the refractive index of the first color light Lb being equal is not limited to being strictly equal, and includes, for example, a difference in refractive index being within a range of 0.2, and more preferably a difference in refractive index being within a range of 0.1, and the same applies hereinafter.

The first intermediate member 4a includes a first microstructure 41. Therefore, it can be said that the first microstructure 41 is composed of a material whose refractive index of the first color light Lb is the same as that of the transparent electrode 3 serving as the first member.

3 is a longitudinal sectional view showing the first microstructure 41 according to the embodiment. As shown in FIG. 3, the first intermediate member 4a includes the first microstructure 41. The first microstructure 41 is composed of a plurality of protrusions 41A that taper toward the alignment film 5 side in the stacking direction Z. The protrusions 41A may have any shape, for example, a quadrangular pyramid shape, a cone shape, a bell shape, etc. The protrusions 41A are provided in a matrix shape in a plane intersecting the stacking direction Z, that is, in a plane along the surface of the transparent electrode 3. The height h1 of the first microstructure 41 may be any height. The height h1 of the first microstructure 41 refers to the length of the first microstructure 41 along the stacking direction Z, and can also be said to be the length of the protrusions 41A along the stacking direction Z. In addition, the pitch P1 of the unevenness in the planar direction intersecting the stacking direction between adjacent protrusions 41A is equal to or less than the wavelength of the first color light Lb. The pitch P1 refers to the distance between the center lines of adjacent protrusions 41A. By applying a microstructure 41 having a pitch P1 on the order of wavelength or less, it is possible to minimize light loss due to scattering, diffraction, etc.

The second intermediate member 4b is made of a material having the same refractive index for the first color light Lb as the alignment film 5 serving as the second member. The material constituting the second intermediate member 4b is preferably the same material as the alignment film 5, and may be, for example, _SiO2 .

2, the second intermediate member 4b includes a second microstructure 42 and a base 43. Therefore, it can be said that the second microstructure 42 and the base 43 are composed of a material having the same refractive index of the first color light Lb as the alignment film 5 as the second member. The base 43 is formed on the alignment film 5 side in the stacking direction Z and is in contact with the alignment film 5. The base 43 may be, for example, flat. The second microstructure 42 is provided on the transparent electrode 3 side of the base 43 in the stacking direction Z. More specifically, the second microstructure 42 is formed on the surface of the base 43 on the transparent electrode 3 side. That is, the second microstructure 42 is formed to protrude from the surface of the base 43 on the transparent electrode 3 side toward the transparent electrode 3 side.

4 is a longitudinal sectional view showing the second microstructure 42 according to the embodiment. As shown in FIG. 4, the second microstructure 42 is composed of a plurality of protrusions 42A that taper toward the transparent electrode 3 in the stacking direction Z. The protrusions 42A may have any shape, such as a quadrangular pyramid shape, a cone shape, or a bell shape. The protrusions 42A are provided in a matrix on a plane intersecting the stacking direction Z, i.e., on the surface of the base 43. The height h2 of the second microstructure 42 may be any height. The height h2 of the second microstructure 42 refers to the length of the second microstructure 42 along the stacking direction Z, and can also be said to be the length of the protrusions 42A along the stacking direction Z. In addition, the pitch P2 of the unevenness in the plane direction intersecting the stacking direction between adjacent protrusions 42A is equal to or less than the wavelength of the first color light Lb. The pitch P2 refers to the distance between the center lines of adjacent protrusions 42A. By applying a microstructure 42 having a pitch P2 of the order of wavelength or less, it is possible to minimize light loss due to scattering, diffraction, etc.

3, the first microstructure 41 does not include a base 43 like the second microstructure 42, but the first microstructure 41 may also include a base. In this case, the base of the first microstructure 41 is also made of a material having the same refractive index of the first color light Lb as the transparent electrode 3 as the first member. The base of the first microstructure 41 is formed on the transparent electrode 3 side in the stacking direction Z and is in contact with the transparent electrode 3. The base may be, for example, flat. The first microstructure 41 is provided on the alignment film 5 side of the base in the stacking direction Z. More specifically, the first microstructure 41 is formed on the surface of the base on the alignment film 5 side, and is formed to protrude from the surface of the base on the alignment film 5 side toward the alignment film 5 side.

2, in the intermediate layer 4, the first microstructure 41 and the second microstructure 42 are arranged so as to be in contact with each other. Specifically, the intermediate layer 4 is configured so that the protrusions 42A of the second microstructure 42 fill the gaps between the protrusions 41A of the first microstructure 41. In other words, the intermediate layer 4 is configured so that the protrusions 41A of the first microstructure 41 fill the gaps between the protrusions 42A of the second microstructure 42. Therefore, in the intermediate layer 4, the area occupied by the first microstructure 41 (protrusions 41A) in a cross section along a direction perpendicular to the stacking direction Z becomes larger toward the transparent electrode 3 side and becomes smaller toward the alignment film 5 side. In addition, in the intermediate layer 4, the area occupied by the second microstructure 42 (protrusions 42A) in a cross section along a direction perpendicular to the stacking direction Z becomes smaller toward the transparent electrode 3 side and becomes larger toward the alignment film 5 side.

Here, the transparent electrode 3 and the alignment film 5 have different refractive indices for the first color light Lb. Therefore, at the interface between the transparent electrode 3 and the alignment film 5, there is a risk of increased reflection of the first color light Lb and the emitted light Lb2. Furthermore, there is a risk of interference fringes appearing in the image displayed by the emitted light Lb2 due to the distribution of the thickness of the liquid crystal layer. In response to this, in the embodiment, an intermediate layer 4 serving as an anti-reflection film is disposed between two members having different refractive indices for the first color light Lb, here between the transparent electrode 3 and the alignment film 5, thereby suppressing reflection while also suppressing the occurrence of interference fringes. The function of the intermediate layer 4 will be described in more detail below.

Figure 5 is a graph showing the correlation between the thickness and refractive index in the stacking direction Z of the intermediate layer 4 according to the embodiment. The horizontal axis of Figure 5 indicates the refractive index of the first color light Lb, and the vertical axis indicates the thickness of the intermediate layer 4 in the stacking direction. In Figure 5, the refractive index n1 indicates the refractive index of the first color light Lb in the transparent electrode 3, and the refractive index n2 indicates the refractive index of the first color light Lb in the alignment film 5. As described above, the intermediate layer 4 is arranged in the order of the transparent electrode 3, the first microstructure 41, the second microstructure 42, and the alignment film 5 from the transparent electrode 3 side to the alignment film 5 side. The transparent electrode 3 and the first microstructure 41 have the same refractive index of the first color light Lb, and the second microstructure 42 and the alignment film 5 have the same refractive index of the first color light Lb. The first microstructure 41 and the second microstructure 42 have a larger area occupied by the first microstructure 41 toward the transparent electrode 3 side, and a larger area occupied by the second microstructure 42 toward the alignment film 5 side. Therefore, the refractive index of the first color light Lb changes continuously in the stacking direction Z in the intermediate layer 4 without abrupt changes. This makes it possible to suppress the occurrence of interference fringes while suppressing reflection. In other words, the intermediate layer 4 can reduce discontinuity in the refractive index at the interface between the transparent electrode 3 and the alignment film 5. As a result, the intermediate layer 4 can obtain an excellent anti-reflection effect that has little dependence on the wavelength and incident angle of the transmitted light.

In the embodiment, the first microstructure 41 and the second microstructure 42 have a plurality of protrusions 41A, 42A, which are interlocked to form a so-called moth-eye structure. However, the shape of the first microstructure 41 and the second microstructure 42 is not limited to a structure in which a plurality of protrusions interlock. The first microstructure 41 and the second microstructure 42 may have any configuration, for example, such that the area occupied by the first microstructure 41 (protrusions 41A) in a cross section of the intermediate layer 4 along a direction perpendicular to the stacking direction Z increases toward the transparent electrode 3 side, and the area occupied by the second microstructure 42 (protrusions 42A) in a cross section of the intermediate layer 4 along a direction perpendicular to the stacking direction Z increases toward the alignment film 5 side.

In addition, in the above description, the intermediate layer 4 is provided between the transparent electrode 3 and the alignment film 5, but it may be disposed at any position between the first member and the second member that have different refractive indices for the first color light Lb. That is, in the above description, the transparent electrode 3 corresponds to the first member and the alignment film 5 corresponds to the second member, but the first member and the second member are not limited to the transparent electrode 3 and the alignment film 5, and may be any member that has a different refractive index for the first color light Lb.

<Modification>
6 is a vertical cross-sectional view showing a reflective liquid crystal display element 1 according to a modified example of the embodiment. In this modified example, the same matters as in the above embodiment will be omitted and only the characteristic parts will be described.

As shown in FIG. 6, in the modified example, an intermediate layer 4A is disposed between the glass substrate 2 and the transparent electrode 3.

The first intermediate member 4a of the intermediate layer 4A is made of a material having the same refractive index for the first color light Lb as the glass substrate 2. That is, the first microstructure 41 of the first intermediate member 4a of the intermediate layer 4A is made of a material having the same refractive index for the first color light Lb as the glass substrate 2. Other than this point, the first intermediate member 4a of the intermediate layer 4A may have the same structure as the first intermediate member 4a of the intermediate layer 4 described above. Note that, if the first intermediate member 4a of the intermediate layer 4A includes a base material, this base material is also made of a material having the same refractive index for the first color light Lb as the glass substrate 2.

The second intermediate member 4b of the intermediate layer 4A is made of a material having the same refractive index for the first color light Lb as the transparent electrode 3. That is, the second microstructure 42 and the base 43 of the second intermediate member 4b of the intermediate layer 4A are made of a material having the same refractive index for the first color light Lb as the transparent electrode 3. Other than this point, the second intermediate member 4b of the intermediate layer 4A may have the same structure as the second intermediate member 4b of the intermediate layer 4 described above.

＜Effects＞
As described above, according to the embodiment, in the reflective liquid crystal display element 1, the transparent electrode 3 and the alignment film 5 are formed in a flat plate shape. The first intermediate member 4a includes a first microstructure 41 having a pitch of unevenness in a planar direction intersecting with the stacking direction that is equal to or less than the wavelength of the light and having the same refractive index as the transparent electrode 3. The second intermediate member 4b includes a second microstructure 42 having a pitch of unevenness in a planar direction intersecting with the stacking direction that is equal to or less than the wavelength of the light and having the same refractive index as the alignment film 5. With this configuration, the first intermediate member 4a and the second intermediate member 4b can suppress the reflection of light passing through the transparent electrode 3 and the alignment film 5. That is, the intermediate layer 4 having the first intermediate member 4a and the second intermediate member 4b of the sub-wavelength order is present at the interface between the members where the reflected light occurs. The intermediate layer 4 can substantially eliminate the discontinuity in the refractive index at the interface between the members, and can obtain an excellent anti-reflection effect with small dependency on the wavelength and incident angle of the transmitted light. As a result, in a projection type liquid crystal display device 100 using a highly coherent light source such as a laser light source, degradation of image quality due to interference fringes can be significantly improved. Also, the transparent electrode 3 and the alignment film 5 are formed in a flat plate shape, and the intermediate layer 4 is disposed between the transparent electrode 3 and the alignment film 5. As a result, the shape of the transparent electrode 3, such as its plate thickness, does not change, and fluctuations in the voltage applied to the transparent electrode 3 are unlikely to be induced structurally. Therefore, the voltage applied to the transparent electrode 3 can be stabilized by a structure that is not a microstructure, while the reflection of the transmitted light can be suppressed by the first intermediate member 4a and the second intermediate member 4b used in the intermediate layer 4.

According to the embodiment, the area of the first microstructure 41 in the cross section perpendicular to the stacking direction Z of the intermediate layer 4 increases toward the transparent electrode 3. The area of the second microstructure 42 in the cross section perpendicular to the stacking direction Z increases toward the alignment film 5. With this configuration, the refractive index of the first intermediate member 4a and the second intermediate member 4b can be changed continuously.

According to the embodiment, the first microstructure 41 is formed so that its cross section tapers toward the alignment film 5 side. The second microstructure 42 is formed so that its cross section tapers toward the transparent electrode 3 side. The intermediate layer 4 is formed by filling the gaps between the first microstructure 41 and the second microstructure 42. With this configuration, the refractive index of the first intermediate member 4a and the second intermediate member 4b can be changed continuously.

According to the embodiment, the pitch P1 of the concaves and convexes of the first microstructure 41 and the pitch P2 of the concaves and convexes of the second microstructure 42 are equal to or less than the wavelength of light. With this configuration, the reflection of the light passing through the first intermediate member 4a and the second intermediate member 4b used in the intermediate layer 4 can be suppressed.

According to the embodiment, the first intermediate member 4a is formed by filling the gaps of the second microstructure 42 with the first microstructure 41. With this configuration, the first intermediate member 4a can be constructed only from the portion having the first microstructure 41, and the refractive index of the first intermediate member 4a can be changed continuously. As a result, there are no wasted portions in the first intermediate member 4a, and it is easy to optimize the design dimensions when constructing the intermediate layer 4.

According to the embodiment, the second intermediate member 4b is formed on the alignment film 5 side of the second microstructure 42 and is in contact with the alignment film 5, and has a base 43 made of a material with the same refractive index as the alignment film 5. With this configuration, the first intermediate member 4a is offset by the second intermediate member 4b and can be constructed only from the portion having the first microstructure 41, and the refractive index of the first intermediate member 4a can be changed continuously. As a result, there are no wasted portions in the first intermediate member 4a, making it easier to optimize the design dimensions when constructing the intermediate layer 4.

According to the embodiment, the liquid crystal display device 100 includes a reflective liquid crystal display element 1. With this configuration, the voltage applied to the transparent electrode 3 can be stabilized by a structure that is not a microstructure, while the reflection of the transmitted light can be suppressed by the first intermediate member 4a and the second intermediate member 4b made of an insulator.

[others]
The above-described components include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the above-described configurations can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the configurations are possible without departing from the scope of the present invention.

REFERENCE SIGNS LIST 1 reflective liquid crystal display element 2 glass substrate 3 transparent electrode 4, 4A intermediate layer 4a first intermediate member 4b second intermediate member 5 alignment film 6 liquid crystal layer 7 alignment film 8 reflective electrode 9 semiconductor drive substrate 10 light emitting device 12 illumination optical system 14 (14b, 14g, 14r) liquid crystal panel 16 synthesis optical system 18 projection optical system 20 control unit 22 optical element 23 optical element 24 optical element 41 first fine structure 41A protrusion 42 second fine structure 42A protrusion 43 base 100 liquid crystal display device

Claims (7)

A reflective liquid crystal display element that reflects incident light,
A flat plate-shaped first member;
a flat-plate-shaped second member provided opposite the first member in the stacking direction and having a refractive index different from that of the first member;
an intermediate layer provided between the first member and the second member in the stacking direction, the intermediate layer including a first intermediate member and a second intermediate member in contact with the first intermediate member on a side closer to the second member than the first intermediate member;
Equipped with
the first intermediate member includes a first microstructure having a pitch of projections and recesses in a planar direction intersecting with the stacking direction that is equal to or smaller than the wavelength of the light, the first microstructure being made of a material having a refractive index of the light that is the same as that of the first member;
the second intermediate member includes a second microstructure having a pitch of projections and recesses in a planar direction intersecting with the stacking direction that is equal to or smaller than the wavelength of the light, the second microstructure being made of a material having a refractive index of the light that is the same as that of the second member;
The first member and the first intermediate member are made of different materials, and the first intermediate member is composed of only the first microstructure.
Reflective liquid crystal display element. The reflective liquid crystal display element according to claim 1, wherein the area occupied by the first microstructure in a cross section along a direction perpendicular to the stacking direction of the intermediate layer increases toward the first member side, and the area occupied by the second microstructure in a cross section along a direction perpendicular to the stacking direction of the intermediate layer increases toward the second member side. The first microstructure is formed so that a cross section thereof tapers toward the second member side,
The second microstructure is formed so that a cross section thereof tapers toward the first member side,
The intermediate layer is formed by filling gaps between the first microstructure and the second microstructure.
3. The reflective liquid crystal display device according to claim 2. the second intermediate member is formed on the second member side of the second microstructure and in contact with the second member, and has a base made of a material having the same refractive index as the second member;
4. The reflective liquid crystal display device according to claim 1. The first member is a transparent electrode, and the second member is an alignment film.
5. The reflective liquid crystal display device according to claim 1. 6. The reflective liquid crystal display element according to claim 5 , further comprising an intermediate layer different from said intermediate layer, which is formed between said transparent electrode and a glass substrate facing said transparent electrode. A reflective liquid crystal display device according to any one of claims 1 to 6,
Liquid crystal display device.

Images