JP2001042329A - Optical element and display device using that optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element with enhanced efficiency of light utilization and the contrast of output light, and to provide a display device using this optical element. SOLUTION: The main body of the optical element 100 consists of a light guide plate, a light-controlling layer 1 whose diffraction or scattering performance for light is changed under an electric field or magnetic field and a reflection plane 6. The body changes the direction of the light propagating in the light guide plate 3 by using the light-controlling layer 1 and the reflection plane 6 to emit the light. The optical element body 100 is provided with a noise preventing means 101 comprising a polarizing plate 7 as a principal element so as to prevent production of noise light which enters the optical element main body from the exit side of the main body and is then reflected by the aforementioned reflection plane and emitted through the exit face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical element which enhances light use efficiency and enhances the contrast of extracted light, and a display device using the optical element.

[0002]

2. Description of the Related Art A display device using a light guide plate and liquid crystal has been conventionally known. As an example, a display device that uses a light guide plate and a ferroelectric liquid crystal and applies an AC electric field near the relaxation frequency of the goldstone mode to the ferroelectric liquid crystal to cause scattering in the liquid crystal layer (Japanese Patent Application Laid-Open No. Hei 6 (1994) -207). -3
No. 0543) and a display device using a light guide plate and a polymer-dispersed liquid crystal (JP-A-6-347790).

However, in the prior art disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 6-308543, since the application of an AC voltage is indispensable, there is a problem that bit map display cannot be performed by simple matrix driving or active matrix (TFT) driving. There was a point. Further, the above-mentioned Japanese Patent Application Laid-Open No. 6-347790
In the disclosure of the publication, a polymer-dispersed liquid crystal that exhibits scattering properties when no voltage is applied, and shows transparency when a voltage is applied is used. In this case, when the matrix driving is performed, the gap between the electrodes always shows a scattering property, so that it is difficult to display black, and there is a problem that the displayed image is an image having extremely low contrast. In the above prior art,
Because the display is controlled by scattering and transmission, the display surface is illuminated by the illumination on the side where the viewer is looking at the display device, and the scattered light overlaps the display image, displaying not only the color of the light source but also the surrounding illumination light The influence on the image deteriorates the image, and color display is difficult.

In order to solve the above-mentioned conventional problems, a display device using a light guide plate and a reverse mode polymer dispersed liquid crystal (Japanese Patent Application No. 10-21780) has been proposed. FIG. 8 shows a schematic configuration of a display device described in Japanese Patent Application No. 10-21780. This display device
An optical element is provided as a constituent element. This optical element is a substrate on which a light guide plate 3 provided with a transparent electrode 2-1 and divided mirror-reflective electrodes 2-3 and 2-3 'are provided. 4
Have a structure in which a thin film is interposed as a light control layer 1.
The light control layer 1 is, for example, a reverse mode polymer-dispersed liquid crystal that is in a transmission state when no electric field is applied and in a scattering state when an electric field is applied (Akita Univ., Satoh et al., The Institute of Television Engineers of Japan IDY96-50, p.137-142)
Consists of The reverse mode polymer liquid crystal is, for example, U
It can be easily prepared by irradiating a mixture of a UV-polymerizable liquid crystal such as CL-002 (Dainippon Ink Co., Ltd.) and a nematic liquid crystal such as E-7 (Merck Japan KK) with ultraviolet rays. .

The polymer-dispersed liquid crystal is transparent when no electric field is applied, and the incident light 8 is transmitted through the transparent electrode 2-1.
In the light guide region composed of the light guide plate 3 and the light control layer 1, the reflection is repeated and the light is not emitted to the outside, so that the light is not emitted. When a voltage is applied from the power supply to, for example, the electrode 2-3 'and an electric field is applied, a portion of the polymer dispersed liquid crystal between the electrode 2-3' and the transparent electrode 2-1 to which the electric field is applied is scattered. Alternatively, the light enters a diffraction state, and the guided light is scattered or diffracted on the electrode 2-3 ′ to which a voltage is applied. The scattered or diffracted light is incident on the interface between the light guide plate 3 and the outside of the element at an angle different from that of the guided light, so that the condition of total reflection at the interface is not satisfied and the light is emitted outside the element (in the figure, an arrow indicates Shown). Therefore, only the electric field application portion corresponding to the electrode 2-3 ′ to which the voltage is applied becomes a light emitting state. in this way,
In Japanese Patent Application No. Hei 10-247871, light propagating through the light guide plate is extracted by controlling the scattering and transmission characteristics of the polymer dispersed liquid crystal. In addition, a light absorbing layer is used to prevent light 15 (light incident from a line of sight looking at the display device) entering from a light extraction direction (emission side) from returning to the extraction direction.

[0006]

However, the use of the light absorbing layer in the optical element having the above structure causes the light scattered or diffracted toward the light absorbing layer to be absorbed, thereby deteriorating the light use efficiency. There was a problem to be solved. Also,
If the light absorbing layer is simply removed and a reflection surface is used, noise light is generated, which reflects external light in the device and emits it again, and this noise light works together with the extracted light to reduce the contrast of the extracted light. There was a problem to be solved to lower it. Therefore, an object of the present invention is to provide an optical element capable of increasing the light use efficiency and enhancing the contrast of the extracted light, and a display device using the optical element.

[0007]

In order to solve the above-mentioned problems, an optical element of the present invention and a display device using the optical element have the following features.

[0008] The optical element of the present invention comprises at least a light guide plate, a light control layer whose light diffraction ability or light scattering ability is changed by an electric field or a magnetic field, and a reflection surface, and the light propagating through the light guide plate. An optical element body that emits light by changing the direction of the light control layer and the reflection surface, and light that enters the optical element body from the emission side of the optical element body is reflected by the reflection surface and is again emitted. Noise prevention means for preventing the generation of noise light emitted from the device.

Here, the noise preventing means is a polarizing plate provided on the light guide plate, or a phase difference plate provided on the light guide plate and a polarization plate provided on the phase difference plate. It is preferable that the optical element comprises a polarizing plate provided on the light guide plate and a retardation plate provided above the reflection surface in the optical element body.

Further, the light control layer of the optical element body exhibits birefringence in a transparent state, and the light incident on the reciprocating light generated by the light control layer with a phase difference of １ ／ wavelength and the incident light. It is preferable that the noise prevention means is composed of a material that functions so that the polarization of the emitted light based on the light is orthogonal to that of the light control layer, and the polarizing plate provided on the light guide plate. . Further, the polarizing plate may include an absorbing polarizing plate and a reflecting polarizing plate.

The light control layer is sandwiched between a first electrode made of a light-transmitting material and a second electrode made of a light-transmitting material, or the second electrode is The second electrode may be made of a material that mirror-reflects light, and the second electrode may also serve as the reflection surface.

In the above-described optical element, the first
It is preferable that at least one of the first electrode and the second electrode is a comb-shaped electrode having a plurality of branches.
Further, at least one of the first electrode and the second electrode is an electrode group divided into a plurality of strips, or any one of the first electrode and the second electrode is It may be divided into display pixels. Also,
A first electrode and a second electrode are provided on a lower surface of the light control layer, and the first electrode and the second electrode are formed in a comb shape having a plurality of branches. The second electrode may be arranged such that the plurality of branches are alternately combined.

In the above-mentioned optical element, the reflection surface is preferably a dielectric multilayer film.

The light control layer preferably contains a polymer-dispersed liquid crystal, and the polymer-dispersed liquid crystal is a polymer in which a polymer resin region and a liquid crystal region such as a holographic polymer-dispersed liquid crystal periodically exist. The liquid crystal may be a dispersed liquid crystal or a reverse mode polymer dispersed liquid crystal.

A display device using the optical element of the present invention has at least a light guide plate, a light control layer whose light diffraction ability or light scattering ability is changed by an electric field or a magnetic field, and a reflection surface. An optical element body that emits light by changing the direction of light propagating through the light plate by the light control layer and the reflection surface, and light that enters the optical element body from the emission side of the optical element body is reflected by the reflection surface And a noise preventing means for preventing generation of noise light which is emitted from the emission surface again. Here, the optical element used for the display device is preferably the above-described optical element.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical element according to the present invention comprises a light-transmitting light-guiding plate for guiding light by entering light from an end face, and a light control layer whose light diffraction ability or light scattering ability is changed by an electric field or a magnetic field. An optical element main body that emits light by changing the direction of light propagating through the light guide plate by the light control layer and the reflection surface, and the optical element main body from the emission side of the optical element main body. And a noise prevention means for preventing light emitted into the element main body from being reflected on the reflection surface and emitted again from the emission surface. The “noise prevention means” used in this specification includes (1) providing a polarizing plate,
(2) It can be roughly divided into providing a polarizing plate and a retardation plate.
As the polarizing plate, an absorption type polarizing plate and a reflection type polarizing plate may be used in combination. Further, the retardation plate may be provided inside the polarizing plate (above the light guide plate) to be integrated with the polarizing plate, or may be provided above the reflection surface in the optical element body and separated from the polarizing plate. Further, it is desirable that the above-described noise prevention means is combined with a configuration in which light is guided in the light guide plate. That is, it is desirable to reflect the light being guided (light nearly parallel to the light guide plate) and reflect the light emitted from the light guide plate (light near perpendicular to the light guide plate). In order to cause total reflection (reflecting light closer to parallel than the critical angle) on the surface of the light guide plate, a gap A (an “angle-selective reflector made of gas”) may be provided above the light guide plate. A low-refractive-index thin film (a solid “angle-selective reflector”) such as a thin film (manufactured by Asahi Glass Co., Ltd.) may be provided. Further, for example, an “angle-selective reflector” having a reflectivity that varies depending on the angle, such as a dielectric multilayer film, may be provided.

Here, "absorption-type polarizing plate" means an optical element that absorbs a specific polarization component of incident light and transmits orthogonal polarization components. In this case, the specific polarization component is not limited to linearly polarized light, but may be circularly polarized light. In the case of circularly polarized light, one of the left and right polarized lights is transmitted and the other is absorbed. Ordinary polarizing plates belong to this category.

On the other hand, the "reflective polarizing plate" refers to an optical element that reflects a specific polarization component of incident light and transmits orthogonal polarization components. The specific polarization component is not limited to linearly polarized light, but may be circularly polarized light. In the case of circularly polarized light, one of the left and right polarized lights is transmitted and the other is reflected. As a material that reflects circularly polarized light, a polymer liquid crystal having chiral nematic alignment can be mentioned, and as a material that reflects linearly polarized light, DBEF (Dual Brightness En) manufactured by 3M Company can be used.
hancement Film).

The "retardation plate" is a light-transmitting flat plate or thin film element having a refractive index anisotropy. When a light beam is transmitted through the retardation plate, the light beam crosses at right angles. It refers to an optical material in which the phase relationship of light between polarized components changes before and after incidence. However, a polymer-dispersed liquid crystal in which a low-molecular liquid crystal is dispersed in a polymer liquid crystal is used for the light control layer, and the orientation direction is homogenously aligned with an alignment film or the like so that the polymer-dispersed liquid crystal layer exhibits a birefringence. Thereby, it can be made to function as a phase difference plate. In this case, the phase difference plate can be omitted by setting the light control layer made of the polymer-dispersed liquid crystal so as to cause a 1/4 phase difference in the incident light.

The "reflection surface" is for reflecting light specularly. For example, a film made of a metal such as aluminum or a dielectric multilayer film is separately provided on an optical element, or, for example, an electrode is specularly reflected. The electrode itself may be used as the reflecting surface by making the electrode from a material that is made of a material having a high refractive index.

FIG. 1 is a side sectional view showing an example of the optical element of the present invention. The optical element includes a light control layer 1, a first electrode 2-1 provided to sandwich the light control layer 1, and a second electrode 2-2 formed of a plurality of divided electrode groups.
A light guide plate 3 provided on the upper surface of the first electrode, a substrate 4 provided on the lower surface of the second electrode 2-2, and a position for uniformizing polarized light on the lower surface of the substrate 4. An optical element main body 100 including a phase difference plate 5 and a reflection surface 6 provided through the phase difference plate 5 for improving the degree of scattering, and provided on the upper surface of the light guide plate 3 with a gap A therebetween. Polarizing plate 7
It is composed of In the optical element of this example, the noise preventing means 101 is composed of the polarizing plate 7 provided above the light guide plate 3 and the retardation plate 5 provided on the upper surface of the reflection surface 6 in the optical element body. Become.

The light control layer 1 is made of a material whose diffraction ability or scattering ability is changed by an external field such as an electric field or a magnetic field. For the light control layer 1, for example, a general polymer-dispersed liquid crystal in which nematic liquid crystal droplets are randomly dispersed in an isotropic polymer resin can be used. When a mode polymer-dispersed liquid crystal is used, a specific effect can be obtained. That is, when the holographic polymer dispersed liquid crystal or the reverse mode polymer dispersed liquid crystal is used for the light control layer 1, the contrast of the display device can be increased.

Next, the operation of the optical element will be described with reference to FIG. Although the direction of the light incident on the light guide plate 3 is various, attention is paid to the incident light 8 in a certain direction, which is indicated by an arrow in the drawing. When the light control layer 1 is formed using a general polymer dispersed liquid crystal, the light guided through the light guide plate 3 is scattered and emitted because the polymer dispersed liquid crystal is usually in a scattering state. On the other hand, when an electric field is applied between the opposing electrodes 2-1 and 2-2, the polymer-dispersed liquid crystal becomes transparent and the emitted light is suppressed. That is, in the figure, when a voltage is applied to the upper and lower two electrodes on the right side and an electric field is applied to the light control layer 1 in that portion, the shaded area becomes a scattering state, and the unshaded area becomes a transparent state. Becomes The incident light 8 is totally reflected on the upper surface of the reflection plate, and is guided by being reflected on the reflection surface 6 provided on the lower surface of the reflection plate, and propagates as long as the polymer dispersed liquid crystal is transparent. Then, by reaching the polymer-dispersed liquid crystal region in the scattering state and scattering, the propagation direction is changed,
An outgoing light component (shown as outgoing light 9 in the figure) is generated. As shown in FIG. 1, it is possible to control the place where light is extracted by dividing one of the electrodes sandwiching the light control layer 1, but the form of division is arbitrary. The division format may be, for example, a strip shape or a display pixel unit.

The medium (air in the figure) in contact with the surface (outgoing interface) of the light guide plate 3 on the side opposite to the light control layer 1 has a smaller refractive index than the light guide plate because it causes total reflection. Light control layer 1
When the refractive index of the light guide plate 3 is substantially equal to or larger than the refractive index of the light guide plate 3, the incident light 8 is efficiently scattered. However, these refractive indexes are basically arbitrary.

When the polarizing plate 7 is provided on the front surface of the optical element body 100, the emission component is limited to the axial direction where the transmission of the polarizing plate 7 is easy, but the controllability of the intensity of the emitted light is not impaired. On the other hand, with respect to the incident light from the emission side, when the polymer-dispersed liquid crystal is in a transparent state, the light is reflected by the reflection surface 6 in the optical element main body 100 without the polarizing plate 7 and returns as noise light. As a result, the emitted light and the noise light cannot be distinguished from each other, which causes a decrease in contrast. However, in the configuration in which the axial direction of the phase difference plate 5 is arranged at an angle of 45 degrees with respect to the transmission axis of the polarizing plate 7, the light incident from the emission side reciprocally receives a half-wave phase difference and the polarization direction becomes 90 degrees.
Since the light is rotated by an angle and absorbed by the polarizing plate 7, the influence of light incident from the emission side can be completely removed. That is, generation of noise light can be prevented.

Further, a polymer-dispersed liquid crystal in which a low-molecular liquid crystal is dispersed in a polymer liquid crystal is used as the light control layer 1, and the orientation direction thereof is made uniform by an alignment film or the like. By expressing the ratio, the polymer-dispersed liquid crystal layer can function as a retardation plate.
In this case, the phase difference plate 5 can be omitted, and the optical element and a display device using the optical element can be simplified.

Hereinafter, the optical element of the present invention will be described in more detail with reference to the drawings.

[0028]

(Embodiment 1) FIG. 2 shows a first embodiment of the optical element of the present invention.
(A) is a side sectional view of the optical element, and (b) is an optical element body 1 constituting the optical element.
It is a schematic plan view which shows the divided electrode provided in 00. The optical element includes a light control layer 1 and the light control layer 1.
And a light guide plate 3 provided on an upper surface of the transparent electrode 2-1; and a transparent electrode 2-2 formed of a plurality of divided electrode groups. A substrate 4 provided on a lower surface of the transparent electrode 2-2; a light guide plate 3 provided on an upper surface of the transparent electrode 2-1;
An optical element body 100 having a phase difference plate 5 on the lower surface of the light guide plate 5 and a reflection surface 6 formed of a reflection plate provided on the lower surface of the phase difference plate 5, and a gap A on the upper surface of the light guide plate 3. And a polarizing plate 7 provided therebetween. In the present embodiment, the noise prevention means 101 includes the polarizing plate 7 and the optical element body 1.
And a retardation plate 5 provided on the upper surface of the reflection surface 6 in the first reference numeral 00.

The optical element having such a configuration is manufactured, for example, as follows.

First, two glass substrates such as 7059 (Corning (USA)) are prepared, and an ITO (Indium tin oxide) film is formed on each of the substrates by sputtering or the like. Next, a liquid crystal such as E-7 (Merck Japan KK) and a liquid crystal such as NOA-65 (Norland P)
polymer-dispersed liquid crystal made of a photocurable resin such as products, Inc. (USA)) is sandwiched from both sides by a substrate on which an ITO film is formed. The polymer-dispersed liquid crystal contains, for example, microspheres having a diameter of about 20 microns in order to keep the gap between the substrates constant. By exposing the polymer-dispersed liquid crystal containing microspheres to ultraviolet light, a light control layer having a thickness equal to the diameter of the microspheres is formed. Next, after a film-like retardation plate is attached to one surface of the substrate 4, aluminum is evaporated to form the reflection surface 6. Further, the optical element of this embodiment is configured by providing the polarizing plate 7 with a slight gap provided on the upper surface of one glass substrate serving as the light guide plate 3.

The operation of the optical element thus configured is as described above with reference to FIG. By dividing the electrode 2-2 on one substrate 4 as shown in FIG. 3, the place where light is extracted can be controlled. The combination of the resin and the liquid crystal is not limited to this. The thickness of the light control layer 1 made of a polymer-dispersed liquid crystal varies depending on the required degree of scattering.
It is about 00 microns.

In this embodiment, the air gap A is present between the light guide plate 3 and the polarizing plate 7 in order to maintain the light guide characteristics of the light guide plate 3. The light guide plate 3 and the polarizing plate 7 may be adhered to each other if the light guide plate 3 is provided on the surface and reflects light in the light guide plate 3.

In this embodiment, the light guide plate 3 and the substrate 4 are also used, but they may be separately provided and adhered to each other. Further, in the present embodiment, the reflection surface 6 and the retardation plate 5 are provided outside the substrate 4 respectively, but they may be provided inside the substrate 4 (the side where the light control layer 1 is located). In this case, the reflecting surface 6
Alternatively, an electrode made of a material that mirror-reflects light may be used as the electrode 2-2. In such a configuration, the substrate on which the reflection surface is provided does not need to be translucent. In addition, those skilled in the art can easily understand that the configuration of the optical element body can be variously changed.

Embodiment 2 FIG. 3 is a side sectional view showing a second embodiment of the optical element of the present invention. The optical element includes a light control layer 1 and a transparent electrode 2 provided on the upper surface of the light control layer 1.
-1, a reflective surface 6 made of a dielectric multilayer film provided on the lower surface of the light control layer 1, an electrode 2-3 provided on the lower surface of the reflective surface 6, and an upper surface of the transparent electrode 2-1. An optical element main body 100 having a light guide plate 3 provided on the light guide plate 3 and a substrate provided on the lower surface of the electrode 2-3, and a phase difference provided above the light guide plate 3 via a gap A. It comprises a plate 5 and a polarizing plate 7 provided on the upper surface of the retardation plate 5. The noise prevention means 101 in this embodiment includes a polarizing plate 7 and a retardation plate 5 provided on the lower surface of the polarizing plate.

The optical element having such a configuration is manufactured, for example, as follows. First, 7059 (co
An ITO film is formed by sputtering or the like on a glass substrate of a company such as Ringing (USA). Further, an electrode such as copper is processed on a glass epoxy substrate as in the case of manufacturing a normal printed board, and then a reflective surface made of a dielectric multilayer film is formed on the electrode by vapor deposition. Next, a liquid crystal such as E-7 (Merck Japan KK) and NOA-6
5 (Norland Products, Inc. (USA)), a polymer-dispersed liquid crystal made of a photocurable resin is sandwiched between the two substrates described above from both sides. This polymer-dispersed liquid crystal has, for example, a diameter of 1 to keep the distance between the substrates constant.
Microspheres of about 00 microns are contained. By exposing the polymer-dispersed liquid crystal containing microspheres to ultraviolet light, a light control layer having a thickness equal to the diameter of the microspheres is formed. Next, the optical element of this embodiment is configured by providing the phase difference plate 5 above the glass substrate serving as the light guide plate via the gap A and the polarizing plate 7 on the upper surface of the phase difference plate 5.

The operation of the optical element thus configured is as described above with reference to FIG. By dividing the electrodes on one substrate as shown in FIG. 3, the place where light is extracted can be controlled. The combination of the resin and the liquid crystal is not limited to this. The thickness of the polymer-dispersed liquid crystal region serving as the light control layer 1 is approximately several microns to several hundred microns, which varies depending on the required degree of scattering.

In this embodiment, the gap A is present between the light guide plate 3 and the phase difference plate 5 in order to maintain the light guide characteristics of the light guide plate 3. An angle-selective reflector or the like may be provided between them to reflect light in the light guide plate.

In this embodiment, the light guide plate and the substrate are also used, but they may be separately provided and adhered to each other. Further, in the present embodiment, the reflection surface 6 is provided inside the substrate,
By forming the substrate 4 and the electrodes 2-3 from a translucent material, the reflecting surface 6 may be provided outside the substrate as shown in the first embodiment. In addition, those skilled in the art can easily understand that the configuration of the optical element body 100 can be variously changed.

When a polarizing plate is used, the rotated component light can be removed and the contrast can be improved, but the component whose polarization direction has not changed cannot be removed. In the optical elements of Example 1 and Example 2, the polarizing plate 7 and the phase difference plate 5 are used in combination as the noise prevention means 101. The contrast can be further improved by using the phase difference plate 5 and controlling the phase difference between the incident light and the reflected light to be half the wavelength.

In the second embodiment, since the retardation plate 5 is provided independently of the optical element body 100, the parameters of the retardation plate can be freely set.

(Embodiment 3) FIG. 4 is a side sectional view showing a third embodiment of the optical element of the present invention. The optical element is configured in the same manner as in Example 2 except that the polarizing plate 7 is constituted by a reflective polarizing plate 7a and an absorbing polarizing plate 7b. That is, the optical element body 10 configured in the same manner as in the second embodiment
0, a phase difference plate 5 provided on the upper surface of the light guide plate 3 serving as the uppermost layer of the optical element main body 100 via a gap A, and a reflection type polarizing plate 7a provided on the upper surface of the phase difference plate 5. And an absorption type polarizing plate 7b provided on the upper surface of the reflection type polarizing plate 7a.
It is composed of Noise prevention means 1 in this embodiment
Numeral 01 is composed of the retardation plate 5, the reflection type polarizing plate 7a and the absorption type polarizing plate 7b. Reflective polarizing plate 7a and absorbing polarizing plate 7b
The optimum condition is the case where the polarization directions for easy transmission are matched.

The optical element having such a structure is manufactured in the same manner as that of the embodiment 2 except that the polarizing plate 7 is composed of the reflective polarizing plate 7a and the absorbing polarizing plate 7b. . That is, first, 7059 (corning
(U.S.A.) and other IT
An O film is formed. Further, an electrode such as copper is processed on a glass epoxy substrate as in the case of manufacturing a normal printed board, and then a reflective surface made of a dielectric multilayer film is formed on the electrode by vapor deposition. Next, a liquid crystal such as E-7 (Merck Japan KK) and a NOA-65 (No.
and a polymer-dispersed liquid crystal composed of a photocurable resin such as land products, Inc. (USA).
Sandwiched between two substrates. The polymer-dispersed liquid crystal contains, for example, microspheres having a diameter of about 100 microns in order to keep the distance between the substrates constant. By exposing the polymer-dispersed liquid crystal containing microspheres to ultraviolet light, a light control layer having a thickness equal to the diameter of the microspheres is formed. Next, a phase difference plate 5 is provided above the glass substrate serving as the light guide plate 3 via a gap, a reflective polarizing plate 7a is provided on the upper surface of the phase difference plate 5, and an absorption type polarizing plate is provided on the upper surface of the reflective polarizing plate 7a. 7b, the optical element of this embodiment is configured.

The operation of the optical element thus configured is as described above with reference to FIG. By dividing the electrode 2-3 on one substrate 4 as shown in FIG. 4, the place where light is extracted can be controlled. The combination of the resin and the liquid crystal is not limited to this. The thickness of the polymer-dispersed liquid crystal region serving as the light control layer 1 is approximately several microns to several hundred microns, which varies depending on the required degree of scattering.

In this embodiment, the gap A is present between the light guide plate 3 and the phase difference plate 5 in order to maintain the light guide characteristics of the light guide plate 3. An angle-selective reflector or the like may be provided between them to reflect light in the light guide plate.

In this embodiment, the light guide plate and the substrate are also used, but they may be separately provided and adhered to each other. Further, in the present embodiment, the reflection surface 6 is provided inside the substrate,
By forming the substrate 4 and the electrodes 2-3 from a light-transmitting material, the reflection surface 6 may be provided outside the substrate 4 as shown in the first embodiment. In addition, those skilled in the art can easily understand that the configuration of the optical element body 100 can be variously changed.

In the first or second embodiment, when light is extracted through the polarizing plate 3, a loss of a component perpendicular to the transmission axis occurs. In the present embodiment, however, the loss is caused by providing the reflective polarizing plate 7a on the light guide plate 3 side. Can be returned to the light guide plate. As a result, an improvement in light use efficiency can be expected as compared with Examples 1 and 2.

The noise prevention means which is a feature of the present invention has been described in detail according to the first to third embodiments.
In the optical element of the present invention, the structure of the optical element main body can be variously modified without departing from the gist of the present invention. Some of such modifications are shown in the following examples.

In the optical elements described in Examples 1 to 3, E
-7 (Merck Japan KK)
OA-65 (Norland Products, In
c (U.S.A.), the light control layer 1 was formed using a polymer dispersed liquid crystal comprising a photocurable resin. The material used for the light control layer 1 is not limited to these, and a general polymer dispersed resin may be used. In particular, when a holographic polymer-dispersed liquid crystal or a reverse mode polymer-dispersed liquid crystal is used, a special effect is obtained as described later. These are described below in Examples 4 and 5.

(Embodiment 4) The optical element of this embodiment has the same configuration as that of Embodiment 3 except that a holographic polymer dispersed liquid crystal is used for the light control layer. As shown in FIG. 4, the noise prevention means 101 in this embodiment includes a phase difference plate 5, a reflection type polarizing plate 7 a provided on the top surface of the phase difference plate 5, and a reflection type polarizing plate 7 a provided on the top surface of the reflection type polarization plate 7 a. And the absorbing polarizer 7b provided.

The optical element having such a configuration is manufactured, for example, as follows. First, 7059 (co
An ITO film is formed by sputtering or the like on a glass substrate of a company such as Ringing (USA). Further, an electrode such as copper is processed on a glass epoxy substrate so as to produce a normal printed board, and then a reflective surface 6 made of a dielectric multilayer film is formed on the electrode by vapor deposition. Next, using the above-mentioned glass substrate and a transparent film, a liquid crystal such as E-7 (Merck Japan KK) and NOA-65, for example.
(Polymer-dispersed liquid crystal composed of a photocurable resin such as Norland Products, Inc. (USA)) is sandwiched between the two substrates described above from both sides. This polymer-dispersed liquid crystal has, for example, a diameter of 1 to keep the distance between the substrates constant.
Microspheres of about 00 microns are contained. By exposing the polymer-dispersed liquid crystal containing microspheres to interference fringes generated by laser light, the light control layer 1 (holographic polymer-dispersed liquid crystal layer) having a thickness equal to the diameter of the microspheres is exposed. ) Is formed. Next, the transparent film is peeled off, and the above-mentioned glass epoxy substrate is bonded. Further, a phase difference plate is provided above a glass substrate serving as a light guide plate via a gap A and an absorption type polarizing plate 7b provided on a top surface of the phase difference plate via a reflection type polarizing plate 7a. An example optical element is constructed.

In this embodiment, a reflection hologram is formed by the distribution of liquid crystal droplets dispersed in a polymer resin.
It is necessary to irradiate light from both sides of the polymer-dispersed liquid crystal region, and a translucent film was used instead of a non-translucent glass epoxy substrate during fabrication. However, in this embodiment, a transmission hologram structure may be formed in a polymer dispersed liquid crystal. In this case, since the light enters the polymer-dispersed liquid crystal region from one side, the interference fringes may be exposed in a state where the mixture is sandwiched between the glass substrate and the glass epoxy substrate without using the film substrate.

The operation of the optical element thus configured is as described above with reference to FIG. By dividing the electrodes on one substrate as shown in FIG. 4, the place where light is extracted can be controlled. The combination of the resin and the liquid crystal is not limited to this. The thickness of the polymer-dispersed liquid crystal region serving as the light control layer 1 is approximately several microns to several hundred microns, which varies depending on the required degree of scattering.

In this embodiment, the gap A is present between the light guide plate 3 and the phase difference plate 5 in order to maintain the light guide characteristics of the light guide plate 3. An angle-selective reflector or the like may be provided between them to reflect light in the light guide plate 3.

In this embodiment, the light guide plate and the substrate are also used, but they may be separately provided and adhered to each other. Further, in the present embodiment, the reflection surface 6 is provided inside the substrate 4. However, by forming the substrate 4 and the electrodes 2-3 from a translucent material, the reflection surface 6 is formed as shown in the first embodiment. It may be provided outside the substrate 4. In addition, the optical element body 100
It can be easily understood by those skilled in the art that the configuration can be variously changed.

In this embodiment, since the diffractive power of the light control layer is changed, a specific color can be displayed even when the light source is white.
Further, the direction in which the directivity of the emitted light is strong can be controlled by using diffraction.

In this embodiment, by providing the reflection type polarizing plate 7a on the light guide plate 3 side, it is possible to return a component which causes a loss to the light guide plate. As a result, an improvement in light use efficiency can be expected as compared with Examples 1 and 2.

As another mode of this embodiment, instead of using the reflective polarizing plate 7a and the absorbing polarizing plate 7b in combination, as shown in the first or second embodiment, an optical system using a normal polarizing plate is used. An element may be configured.

(Embodiment 5) The optical element of this embodiment has substantially the same configuration as that of Embodiment 3 except that a reverse mode polymer dispersed liquid crystal is used for the light control layer. When the light control layer 1 is formed using the reverse mode polymer dispersed liquid crystal, the retardation plate 5 can be omitted as described later.

The optical element is a light control layer 1 as shown in FIG.
And a transparent electrode 2-1 provided on the upper surface of the light control layer 1.
A reflecting surface 6 made of a dielectric multilayer film provided on the lower surface of the light control layer 1, an electrode 2-3 provided on the lower surface of the reflecting surface 6, and an upper surface of the transparent electrode 2-1. Optical element main body 100 including the light guide plate 3 provided above, and a substrate provided on the lower surface of the electrode 2-3, and a reflective polarizer provided above the light guide plate 3 with a gap A therebetween. 7a and a polarizing plate 7 composed of an absorbing polarizing plate 7b provided on the upper surface of the reflective polarizing plate 7a. In this embodiment, the noise prevention means 101 includes a reflective polarizing plate 7a and the reflective polarizing plate 7a.
a of the absorption type polarizing plate 7b provided on the upper surface. The optimum condition is the case where the easy-to-transmit polarization directions of the reflective polarizer 7a and the absorption polarizer 7b are matched.

The optical element having such a configuration is manufactured, for example, as follows. First, 7059 (co
An ITO film is formed by sputtering or the like on a glass substrate of a company such as Ringing (USA). Further, an electrode such as copper is processed on a glass epoxy substrate so as to produce a normal printed board, and then a reflective surface 6 made of a dielectric multilayer film is formed on the electrode by vapor deposition. Then, for example, E-7
Liquid crystal such as (Merck Japan KK) and UCL for example
A polymer-dispersed liquid crystal composed of a liquid crystal monomer such as -002 (Dainippon Ink Co., Ltd.) is sandwiched between the two substrates described above from both sides. The polymer-dispersed liquid crystal contains, for example, microspheres having a diameter of about 100 microns in order to keep the distance between the substrates constant. By exposing the polymer-dispersed liquid crystal containing the microspheres to ultraviolet light, a light control layer 1 (reverse mode polymer-dispersed liquid crystal layer) having a thickness equal to the diameter of the microspheres is formed. Then, a reflective polarizer 7a is provided above the glass substrate serving as the light guide plate 3 via a gap A, and an absorption polarizer 7b is further provided on the upper surface of the reflective polarizer 7a. can get. In this case, the retardation plate 5 can be omitted by adjusting the thickness of the reverse mode polymer-dispersed liquid crystal layer so that the retardation of the light control layer 1 becomes n + 1/4 (n is an integer) wavelength retardation. it can. The best case is obtained when the orientation direction of the light control layer 1 is inclined by 45 degrees with respect to the transmission axis of the polarizing plate.

Here, the reverse mode polymer dispersed liquid crystal is formed by dispersing a low molecular liquid crystal in a liquid crystalline polymer resin. When the light control layer is formed using the reverse mode polymer dispersed liquid crystal, when no electric field is applied,
The light control layer is a uniform film having birefringence between the liquid crystalline polymer resin and the low molecular liquid crystal, and is in a transmission state. When an electric field is applied, the low-molecular liquid crystal is oriented by the electric field, causing a difference in refractive index from the liquid crystalline polymer resin, resulting in a scattering state. When an optical element is configured using such a reverse mode polymer-dispersed liquid crystal, in a transmission state, a uniform refractive index distribution is obtained for light in any direction. Therefore, when such a liquid crystal is applied to a display device, since scattering does not occur in a transmission state, display with high contrast can be performed even from an oblique direction.

When the polarizing plate 7 is provided on the front surface of the above-described optical element body 100, the emission component is limited to the direction of the axis of easy transmission of the polarizing plate 7, but the controllability of the emitted light intensity is not impaired.
Further, of the light components to be emitted, those components that cannot pass through the polarizing plate 7 are also reflected by the polarizing plate 7, returned to the light guide plate, and emitted after the polarization is rotated during the waveguide, so that the light use efficiency is improved. Can be significantly increased. On the other hand, with respect to the light incident from the emission side, the orientation direction is set to be equal to the transmission axis of the polarizing plate 7 by the phase difference of the reverse mode polymer dispersed liquid crystal.
In the configuration in which the light is incident at an angle of 5 degrees, the incident light receives a phase difference of half a wavelength in a reciprocating manner and the polarization direction is rotated by 90 degrees and is reflected by the polarizing plate. Therefore, the influence of the light incident from the emission side is completely removed. You can do it.

The operation of the optical element thus configured is as described above with reference to FIG. By dividing the electrode 2-3 on one substrate 4 as shown in FIG. 4, the place where light is extracted can be controlled. The combination of the resin and the liquid crystal is not limited to this. The thickness of the polymer-dispersed liquid crystal region serving as the light control layer 1 is approximately several microns to several hundred microns, which varies depending on the required degree of scattering.

In this embodiment, the air gap A is provided between the light guide plate and the phase difference plate in order to maintain the light guide characteristics of the light guide plate, but the angle selectivity is provided between the light guide plate and the phase difference plate. A reflector may be provided to reflect the light in the light guide plate.

In this embodiment, the light guide plate and the substrate are also used, but they may be separately provided and adhered to each other. Further, in the present embodiment, the reflection surface 6 is provided inside the substrate 4. However, by forming the substrate 4 and the electrodes 2-3 from a translucent material, the reflection surface 6 is formed as shown in the first embodiment. It may be provided outside the substrate 4. In addition, the optical element body 100
It can be easily understood by those skilled in the art that the configuration can be variously changed.

In this embodiment, by providing the reflection type polarizing plate 7a on the light guide plate 3 side, it is possible to return a component which causes a loss to the light guide plate. As a result, an improvement in light use efficiency can be expected as compared with Examples 1 and 2. Light control layer 1
By using a reverse mode polymer-dispersed liquid crystal in (1), light leakage due to multiple scattering can be reduced, so that an improvement in light use efficiency compared to Example 3 can be expected. Furthermore, in this embodiment, since the scattering direction of the scattered liquid crystal of the reverse mode polymer-dispersed liquid crystal has polarization dependence, by adjusting the polarization transmission direction of the polarizing plate to polarized light having a large intensity of the scattered light,
Efficiency can be improved.

As another mode of this embodiment, instead of using a combination of the reflection type polarizing plate 7a and the absorption type polarizing plate 7b, an optical system using an ordinary polarizing plate as shown in Example 1 or 2 is used. An element may be configured.

In this embodiment, it has been exemplified that the retardation plate 5 can be omitted by using a reverse mode polymer dispersed liquid crystal. However, a reverse mode polymer-dispersed liquid crystal layer (light control layer) whose thickness has been adjusted and a retardation plate may be combined so that the retardation is n + 1/4 (n is an integer) wavelength.

The polymer dispersed liquid crystal used for the light control layer 1 is not limited to the reverse mode polymer dispersed liquid crystal. As an example other than the reverse mode polymer-dispersed liquid crystal, the nematic liquid crystal is homogeneously aligned, a uniform birefringent thin film is formed in the absence of an electric field, and the application of a low-frequency AC voltage induces the Williams domain to change to the scattering state. In this case, the phase difference plate can be omitted.

As described above, in the first to fifth embodiments, the first electrode 2-1 and the second electrodes 2-2,
Although the optical element is configured by dividing one of the electrodes -3, any type and shape of the electrode sandwiching the light control layer 1 may be used. Hereinafter, modified examples of the electrodes used to change the light diffraction ability or light scattering ability of the light control layer will be described.

(Embodiment 6) FIGS. 5A and 5B show a sixth embodiment of the optical element of the present invention. FIG. 5A is a side sectional view of the optical element, and FIG. FIG. 3 is a plan view showing a comb-shaped electrode provided in the optical element body 100. The optical element of this embodiment has the same configuration as that of the third embodiment except that one of the electrodes sandwiching the light control layer 1 has a comb shape and that the light control layer 1 uses a nematic liquid crystal.

That is, the optical element is composed of a substrate (light guide plate 3) in which a transparent electrode 2-1 such as ITO (Indium tin oxide) is provided on a translucent substrate such as glass, and a general substrate such as glass. A substrate 4 having a comb-shaped electrode 2-4 made of, for example, aluminum and a reflecting surface 6 made of a dielectric multilayer film is formed thereon, and the electrodes of these two substrates are used as E-7 (nematic liquid crystal) as nematic liquid crystal. (Merck Japan K.K.). Further FIG.
As shown in (a), a phase difference plate 5, a reflection type polarizing plate 7a, and an absorption type polarizing plate 7b are provided on a translucent substrate (light guide plate 3) via a gap A. The optimum condition is the case where the easy-to-transmit polarization directions of the reflective polarizer 7a and the absorption polarizer 7b are matched.

As shown in FIG. 5B, the comb electrodes 2-4
Has a plurality of branches branched in a comb shape, and the plurality of branches are electrically connected in one or more regions, so that the whole becomes equipotential. Further, the plurality of branches are periodically distributed in such a size that a fine periodic structure that diffracts light can be induced in the light control layer. This comb-shaped electrode can be easily manufactured by depositing an electrode of aluminum or the like to a uniform thickness on a substrate such as glass, and patterning the electrode in accordance with a photolithography technique.

The operation of the optical element thus constructed is as described above with reference to FIG. 1, but the operation of the transparent electrode 2-1 sandwiching the light control layer 1 and the comb-shaped electrode 2-4 is described. When an electric field is applied between them, it becomes possible to induce a refractive index distribution corresponding to the comb-shaped electrode 2-4 in the liquid crystal constituting the light control layer 1. It is possible to control the extraction of light by using diffraction by such a refractive index distribution.

The optical element of this embodiment can be modified in the same manner as in the third embodiment. However, in the present embodiment, since the leakage light due to the multiple scattering of the polymer dispersed liquid crystal can be reduced, the improvement of the light use efficiency can be expected as compared with the third embodiment.

As another mode of this embodiment, instead of using the reflective polarizer 7a and the absorption polarizer 7b in combination, a normal polarizer is used as shown in Embodiment 1 or 2. An optical element may be configured.

(Embodiment 7) FIGS. 6A and 6B show a seventh embodiment of the optical element of the present invention. FIG. 6A is a side sectional view of the optical element, and FIG. FIG. 3 is a plan view showing a comb-shaped electrode provided in the optical element body 100. The optical element of the present invention includes a light control layer 1 and comb-shaped electrodes 2-4a and 2-4a provided on the same plane of a substrate 4 via a reflective surface 6 made of a dielectric multilayer film on the lower surface of the light control layer 1. 4
b, an optical element body 100 having a light guide plate 3 provided on the upper surface of the light control layer 1, a phase difference plate 5 provided on the upper surface of the light guide plate 3 via a gap A, Reflective polarizing plate 7a provided on the upper surface of phase difference plate 5 and reflective polarizing plate 7a
And a polarizing plate 7 composed of an absorption-type polarizing plate 7b provided on the upper surface of the device.
The comb electrodes 2-4a and 2-4b are the same as the comb electrodes used in the seventh embodiment.

In this embodiment, as shown in FIG.
The branch portions of both electrodes are provided on the same substrate so as to be alternately combined. Since a periodic electric field can be formed by such an electrode, it is possible to periodically induce a refractive index distribution in the light control layer. This embodiment is a seventh embodiment.
Since these are essentially the same, other descriptions are omitted.

The optical element according to the present invention has been described with reference to the embodiments. Next, examples of the optical display device of the present invention constituted by the above-described optical element of the present invention will be described below.

(Embodiment 8) FIG. 7 is a side sectional view schematically showing a display device using the optical element of the present invention. The display device according to the eighth embodiment includes a light control layer 1-1 sandwiched by an alignment film 1-2 and a transparent electrode provided on the upper surface of the light control layer 1-1 via the alignment film 1-2. 2-1; a reflection surface 6 formed of a dielectric multilayer film provided on the lower surface of the light control layer 1-1 via an alignment film 1-2; and an electrode 2 provided on the lower surface of the reflection surface 6
-3, a substrate 4 provided on the lower surface of the electrode 2-3, a first end penetrating the substrate 4 and connected to the electrode 2-3, and a second end exposed from the substrate 4 An optical element body 100 having an electrode (back electrode) 2-5 having
A dielectric multilayer film 10 provided above the light guide plate 3;
Reflective polarizing plate 7a provided on the upper surface of the dielectric multilayer film
And a light-absorbing polarizer 7b provided on the upper surface of the reflective polarizer 7a.
The irradiation means 102 includes a cold-cathode tube 11 and a reflector 12 provided so as to surround the periphery of the cold-cathode tube 11. The noise prevention means 101 in the display device of the ninth embodiment includes a polarizing plate 7 composed of a reflective polarizing plate 7a and an absorption polarizing plate 7b provided on the upper surface of the reflective polarizing plate 7a.

The display device of this embodiment can be manufactured as follows. First, for example, through-hole processing is performed on a glass epoxy substrate to prepare a substrate 4 to which a pixel electrode can be connected from the back surface, and a dielectric multilayer film and an alignment film 1-2 serving as a reflection surface 6 are attached to the surface to perform an alignment process. Further, a transparent acrylic plate is used as the light guide plate 3, a transparent electrode 2-1 and an alignment film 1-2 are provided, and an alignment process is performed. The reverse mode polymer-dispersed liquid crystal is sandwiched between the two substrates (the light guide plate 3 and the substrate 4) from both sides, and a dielectric multilayer film 10 is provided on the upper surface of the light guide plate 3; A polarizing plate 7a is provided, and an absorption polarizing plate 7b is provided on the upper surface of the reflective polarizing plate 7a. Further, an illuminating means 102 comprising a cold cathode tube 11 and a reflector 12 is provided.

Incidentally, in the optical element applied to the display device of this embodiment, a dielectric multilayer film 10 is provided between the light guide plate 3 and the phase difference plate 5 in order to maintain the light guide characteristics of the light guide plate 3. However, a void may be present instead of the dielectric multilayer film 10.

In the display device of this embodiment, the intensity of light emitted from the light guide plate can be controlled for each pixel by controlling the voltage applied to the electrodes. Also, the back electrode 2
Since driving can be performed according to −5, the driving substrates can be arranged without gaps, and the screen size of the display device can be easily increased. Further, by using a reverse mode polymer-dispersed liquid crystal for the light control layer, a good black display can be realized for the non-lit pixels.

The optical elements used in the display device of this embodiment are the optical elements described in the fifth embodiment. Of course, the present invention is not limited to these optical elements, but any optical element according to the present invention can be used. May be used.

As described above, in the first to eighth embodiments, all the substrates are described as flat plates. However, a curved surface may be formed in a situation where the leakage of light propagating through the light guide plate is not extremely large. In that case, a flexible substrate such as a flexible printed substrate is suitable. Further, in the embodiment in which the reflection film is formed on the electrode surface, the reflection film may be omitted by using the electrode itself as a reflection surface.

[0086]

As described above, according to the present invention, the following effects can be obtained. The effect of the noise prevention means will be briefly described, and then the effect of the present invention will be described in more detail.

(1) By providing a polarizing plate, it is possible to remove light of a component whose polarization plane has been rotated from the time of incidence from the outside to the time of emission, and it is possible to improve the contrast.

(2) By providing the phase difference plate, the phase difference between the incident light and the reflected light can be controlled to be a half wavelength, and the contrast can be improved.

(3) By providing a reflection type polarizing plate on the light guide plate side, a lossy component can be returned to the light guide plate, and the light use efficiency can be improved.

(4) Since the intensity of the extracted light can be controlled by an electric field or the like, the controllability can be improved, and by providing the reflecting surface, the effect of the polarizing plate can be effectively used.

(5) By using a light control layer in which the phase difference is １ ／ wavelength in the transparent state, the light incident from the outside can be used as a polarization plane to obtain a 波長 wavelength phase difference in the light control layer. Is rotated exactly 90 degrees, so that the contrast can be improved without using a phase difference plate.

(6) Since the polymer-dispersed liquid crystal is a thin film in which birefringent particles are dispersed, it has a strong property of disturbing polarization. Therefore, even if light polarized by a polarizing plate from the outside enters in a scattering state, it is almost emitted. Since the light can be in the non-polarized state, noise light in the scattering state can be significantly reduced.

(7) By using a holographic polymer-dispersed liquid crystal, the polymer-dispersed liquid crystal can be prevented from being in a scattering state even in a state where the guided light is taken out, and the contrast can be increased. It becomes possible. In addition, it is possible to control the directivity of the extracted light.

(8) By driving using a comb-shaped electrode, the liquid crystal can be prevented from being in a scattering state even in a state where the guided light is taken out, and the contrast can be increased. In addition, it is possible to control the directivity of the extracted light.

(9) By using the reverse mode polymer-dispersed liquid crystal, the birefringence in the transparent state can be controlled and the phase difference plate can be omitted, and the element can be simplified.

(10) By using the optical element according to the present invention, a display element having high contrast can be realized.

(11) By arranging a plurality of drive boards, it is possible to easily increase the screen size of the display device.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the operation of an embodiment of the optical element of the present invention.

FIG. 2 shows an embodiment of the optical element of the present invention,
(A) is a side sectional view, and (b) is a schematic plan view showing a divided electrode.

FIG. 3 is a side sectional view showing an embodiment of the optical element of the present invention.

FIG. 4 is a side sectional view showing an embodiment of the optical element of the present invention.

FIG. 5 shows an embodiment of the optical element of the present invention,
(A) is a side sectional view of the optical element, and (b) is a plan view showing a comb-shaped electrode applied to (a).

FIG. 6 shows an embodiment of the optical element of the present invention,
(A) is a side sectional view of the optical element, and (b) is a plan view showing a comb-shaped electrode applied to (a).

FIG. 7 is a side sectional view showing an embodiment of the display device of the present invention.

FIG. 8 is a side sectional view showing an example of a conventional optical element.

[Explanation of symbols]

 1,1-1 Light control layer 1-2 Alignment film 2-1 First electrode (transparent electrode) 2-2 Second electrode (transparent electrode) 2-3 Second electrode (electrode) 2-3 'Electric field 2-4 Second electrode (comb-shaped electrode) 2-4a, 2-4b Comb-shaped electrode 2-5 Back electrode 3 Light guide plate 4 Substrate 5 Phase difference plate 6 Reflecting surface 7 Polarizing plate 7a Reflective polarizing plate 7b Absorption type polarizing plate 8 Incident light 9 Outgoing light 10 Dielectric multilayer film 11 Cold cathode tube 12 Reflector 100 Optical element body 101 Noise prevention means 102 Illumination means A air gap

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/1335 520 G02F 1/1335 520 5G435 1/13363 1/13363 1/1343 1/1343 G09F 9/00 322 G09F 9/00 322Z (72) Inventor Hidetaka Tanaka 2-3-1 Otemachi, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Inventor Masatojo Uehira 2-chome, Otemachi, Chiyoda-ku, Tokyo No. 1 Nippon Telegraph and Telephone Corporation F term (reference) 2H049 BA02 BA05 BA06 BA43 BB03 BC22 2H088 EA48 GA10 HA10 HA15 HA18 MA02 MA20 2H089 HA04 JA06 KA08 QA05 QA12 QA16 TA14 TA15 2H091 FA08X FA08Z FA11X FA11Z FAX FA11 FAX FAZ FC02 FC10 FC23 FD01 FD06 FD15 GA02 JA02 LA03 LA12 LA13 2H092 GA14 PA07 PA10 PA11 5G435 AA02 BB12 DD12 FF03 FF05 FF15

Claims (18)

[Claims] 1. A light guide plate, at least a light control layer whose light diffraction ability or light scattering ability is changed by an electric field or a magnetic field, and a reflection surface, wherein a direction of light propagating through the light guide plate is changed by the light. An optical element main body that is changed and emitted by the control layer and the reflective surface; and a noise light in which light that has entered the optical element main body from the emission side of the optical element main body is reflected by the reflective surface and emitted again from the emission surface. An optical element comprising: a noise prevention unit that prevents generation of a noise. 2. The optical element according to claim 1, wherein the noise prevention unit is a polarizing plate provided on the light guide plate. 3. The optical device according to claim 1, wherein said noise preventing means comprises a phase difference plate provided on said light guide plate and a polarizing plate provided on said phase difference plate. element. 4. The apparatus according to claim 1, wherein the noise prevention means comprises a polarizing plate provided on the light guide plate and a retardation plate provided above the reflection surface in the optical element body. 2. The optical element according to 1. 5. The light, in which the light control layer of the optical element main body exhibits birefringence in a transparent state, and is incident on the reciprocating light generated by the light control layer with a phase difference of 波長 wavelength and the incident light. Characterized in that the noise prevention means is composed of the light control layer and a polarizing plate provided on the light guide plate. The optical element according to claim 1. 6. The optical element according to claim 2, wherein the polarizing plate comprises an absorption type polarizing plate and a reflection type polarizing plate. 7. The light control layer according to claim 1, wherein the light control layer is sandwiched between a first electrode made of a light transmitting material and a second electrode made of a light transmitting material. 7. The optical element according to any one of 6. 8. The optical element according to claim 7, wherein the second electrode is made of a material that reflects light specularly, and the second electrode also serves as the reflection surface. 9. The optical element according to claim 7, wherein at least one of the first electrode and the second electrode is a comb-shaped electrode having a plurality of branches. 10. The optical element according to claim 7, wherein at least one of the first electrode and the second electrode is an electrode group divided into a plurality of strips. . 11. The optical element according to claim 7, wherein one of the first electrode and the second electrode is divided for each display pixel. 12. A first electrode and a second electrode are provided on a lower surface of the light control layer, wherein the first electrode and the second electrode are formed in a comb shape having a plurality of branches, and The optical element according to any one of claims 1 to 6, wherein the first electrode and the second electrode are arranged such that a plurality of branches are alternately combined. 13. The optical element according to claim 1, wherein the reflection surface is a dielectric multilayer film. 14. The optical element according to claim 1, wherein the light control layer contains a polymer dispersed liquid crystal. 15. The liquid crystal display device according to claim 14, wherein the polymer dispersed liquid crystal includes a polymer dispersed liquid crystal in which a polymer resin region and a liquid crystal region are periodically present, such as a holographic polymer dispersed liquid crystal. The optical element as described in the above. 16. The optical element according to claim 14, wherein the polymer dispersed liquid crystal includes a reverse mode polymer dispersed liquid crystal. 17. A light guide plate, at least a light control layer whose light diffraction ability or light scattering ability is changed by an electric field or a magnetic field, and a reflection surface, wherein a direction of light propagating through the light guide plate is changed by the light. An optical element main body that is changed and emitted by the control layer and the reflective surface; and a noise light in which light that has entered the optical element main body from the emission side of the optical element main body is reflected by the reflective surface and emitted again from the emission surface. A display device, comprising: an optical element having noise prevention means for preventing the occurrence of noise. 18. A display device, wherein the optical element is the optical element according to claim 2. Description: