JPS6221123A - Display device - Google Patents

Abstract

PURPOSE:To vary the refractive index of an optical waveguide member directly and to obtain high brightness and high contrast by forming an optical waveguide of an electrooptic member which varies in refractive index by being impressed with an electric field and providing a distributed electric field applying means which forms an equivalent prism by varying the refractive index. CONSTITUTION:This display device consists of the optical waveguide 6 made of the electrooptic member which confines rays of light 2, has light transmissivity, and varies in refractive index by being impressed with an external electric field, a resistance electrode 7, a transparent electrode 8, and an electric field generation controller 9. An electric field is produced between the resistance electrode 7 and transparent electrode 8 at right angles to the optical waveguide 5 and this electric field has distribution variation in parallel to this optical waveguide 6 because of the resistance electrode 7. Therefore, distributed refractive index variation is caused in the optical waveguide 6 at this part owing to electrooptic effect and obtained in the optical waveguide 6 to form the equivalent prism 10. The rays of light 2 are diffracted to vary in angle of reflection, and the rays of light can not be propagated in the optical waveguide 6, so that the light is projected from the optical waveguide 6 as leak light 2'.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a display device using an optical waveguide.

(Prior Art) As a display device that emits light by leaking the propagating light of the optical waveguide to the outside in the middle part of the optical waveguide having a translucent property designed to confine the light, for example, Japanese Patent Laid-Open No. 54-14208
As shown in Publication No. 9, the optical waveguide is limited to a plate-shaped leading wave body, and the refractive index of the external region in contact with a predetermined position on one surface of the plate-shaped leading wave body is changed, A device is known that emits light by leaking propagating light trapped inside a plate-shaped leading wave body to the outside.

This conventional example will be explained with reference to FIG. 6rlJ and FIG. 17.

Figure 16 shows the case when the propagating light does not leak to the outside, and Figure 7 shows the case when the propagating light does not leak to the outside. llt, 'It is a partial longitudinal cross-sectional view showing the time.

As seen in the figure, 1 is the eye, 2 is the light, and 2' is the leaked light.This conventional display device has a plate-shaped guide having translucency so that the light 2 is confined inside. The wave body 3 is arranged in contact with a predetermined position on one surface of the plate-shaped leading wave body 3, or is arranged in such a manner that it can be disposed in contact with a predetermined position on one surface of the plate-shaped leading wave body 3. It is composed of a medium 4 that changes the equipolar refractive index and a shaving device 5 that controls the medium 4.

The medium 4 is movable in response to an external mechanical force, an electric field, or an Ia field, or has electricity, a magneto-optic effect, or an electrostrictive property.

[Problem to be solved]

As mentioned above, in conventional display devices, the medium is brought into contact with or can be brought into contact with one side of the plate-shaped optical waveguide, and the medium is moved to a predetermined position of the plate-shaped optical waveguide by a control device. By changing the equivalent refractive index of the contacting external region, the light trapped within the plate-shaped leading wave body leaked to the outside and emitted light.

The leaked light was leaked to the outside by changing the equipolarized refractive index of the external region in contact with the outside of the plate-shaped optical waveguide, so the direction of the leaked light could not be accurately and stably controlled. brightness.

It was difficult to increase contrast.

Therefore, when this display device is arranged in a matrix to form an image display device, the image quality is adversely affected.

This invention was made to solve the above-mentioned conventional problems, and provides a display device that can achieve high brightness and high contrast by directly changing the refractive index of a member forming an optical waveguide. With the goal.

[Means for solving problems]

In order to achieve the above object, the display device of the present invention includes:
In a display device in which light propagating in the optical waveguide leaks to the outside at a midpoint of an optical waveguide having a translucent property designed to confine light and emit light, the refractive index of the optical waveguide is changed by application of an electric field. A distributed electric field (an electric field with a distribution change) is formed from an electro-optical member and extends through the middle part of the optical waveguide.
and a distributed electric field applying means for generating an equivalent prism by applying a refractive index and changing the refractive index.

[Effect]

In the display device having the above configuration, light is incident on the optical waveguide from an external light source. The incident light that satisfies the conditions for total reflection propagates within the optical waveguide through repeated total reflection. The propagated light is
The beam enters an equivalent prism generated by the distributed electric field applying means and changes the reflection angle. Light whose reflection angle has changed is
The light cannot be totally reflected within the optical waveguide and leaks outside from the optical waveguide, becoming leaked light and emitting light (Embodiment) Preferred embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show the basic configuration of the display device of the present invention, and a schematic vertical cross-sectional view of the σ portion is shown! l-0 Figure 1 shows the distributed electric field fJ
Figure 2 shows the distributed electric field (
This is when the J giving means is activated.

In this embodiment, the resistance itWI is used as the μ distribution electric field applying means.
When using M, the light 2 can be confined. An optical waveguide 6 formed of zinc oxide, lead, lanthanum, zircon, titanium oxide? A resistive electrode 7 arranged to generate a distributed electric field, a transparent electrode 8 provided in contact with the optical waveguide 6 on the side opposite to the resistive type @7, and a resistive electrode 7
The electric field generator 1i1NMl device 9 controls the snow pressure.

As shown in factor 8112, an electric field is generated between the resistor rl pole 7 and the transparent electrode 8 in a direction perpendicular to the optical waveguide 6, and since this electric field is caused by the resistor electrode 7, its distribution changes in the direction parallel to the optical waveguide rA6. . Therefore, the leading wave of this part! '86 is the electro-optical effect (Pockels effect).

A distributed refractive index change is given by the Kerr effect, and the refractive index change is caused in the optical waveguide 6 to generate an equivalent prism 10.

When the light 2 passes through the equivalent prism 10, the light 2 is diffracted and the angle of reflection changes, so that it cannot propagate within the optical waveguide 6 and exits from the optical waveguide 6 as the Ill destination light 2'.

In the display device W11 according to this embodiment, as described above, since the equivalent prism 10 can be generated inside the optical waveguide 6, the direction of the leaked light 2' can be accurately and stably illuminated. t211.

FIG. 3 is a partial cross-sectional view taken along line A-B in FIG. 1.

FIG. 3 (a) shows that the optical waveguide 6 is flat and (b)
, as shown in (c), it may be rectangular or circular. Further, the cross-sectional shape can be changed as appropriate depending on the embodiment.

FIG. 4 is a partial schematic diagram of a first embodiment of an image display device to which the display device of the present invention is applied. ! It is the mouth.

In this first embodiment, one resistor pole 7 and a transparent mti 8 are formed in a 7-trix shape with an optical waveguide 6 having a flat cross section sandwiched therebetween.

Reference numeral 11 denotes a light source that inputs light into the optical waveguide 6.

12 is lFl.

Reference numeral 13 denotes an image 1'Jin device which receives a signal of an image to be projected and controls each electric field generation/control device ff9. Although the image III vL device 3 is not shown, it has a row axis selection circuit, a judgment selection concave path, and an image control rlJ exit path, and the uniformity control circuit outputs an image coloring signal. The axis selection circuit instructs which display pixel to select as the row axis, and also instructs the coaxial selection circuit which display pixel to select in the same way as the row axis selection circuit.

That is, by selecting a predetermined display element ii using the image control device of the image control device 13, the me display can be performed.

FIG. 5 shows a second embodiment in which the display device of the present invention is applied.
It is possible to provide an image display technique d that enables color display by adding an optical switch 14 that selects red R, green G, and blue B light and enters the optical waveguide 6.

〔effect〕

As described above, in the display device of the present invention, a light-transmitting optical waveguide capable of confining light is formed using an electro-optic member, and a distributed electric field is applied to a midway portion of the optical waveguide. Since the present invention is equipped with a distributed electric field applying means that changes the refractive index and generates an equivalent prism, it is possible to directly generate a light refraction phenomenon in the optical waveguide, thereby increasing the luminous efficiency.

In addition, since it uses electro-optical materials, it has excellent high-speed response, and requires low voltage and power, making it easy to control leakage light, making it possible to create high-brightness, high-contrast display devices that are less susceptible to the effects of ambient light. .

Furthermore, when the display device of the present invention is used as an image display device, the display device is a single display ii! Since the image display device can be made into a single element unit, high density and high resolution can be achieved, and since the structure of the display device is simple and flat, it is possible to easily realize a thinner image display device and a larger screen.

[Brief explanation of the drawing]

FIG. 1 is a partial schematic vertical cross-sectional view when the display device of the present invention is not operating, FIG. 2 is a partial schematic vertical cross-sectional view when the display device of the present invention is active, and FIG. 3 (a > , <1)
＞, (c) is a sectional view of the structure of the display device of the present invention shown in FIG. 1, FIG. 4 is a schematic g+ view of the structure of the first embodiment of the image display device using the display device of the present invention, FIG. 5 is a schematic structural perspective view of a second practical example of an image display device using the display device of the present invention, FIG. 6 is a partial schematic vertical sectional view when the conventional display device is not operating, and FIG. This is a partially schematic vertical cross-sectional view of a conventional display device in operation. 2...Light, 6...Optical waveguide, 7.8...Distributed electric field (=J giving means, 1o...
...'8!1IIi prism. Applicant NEC Home Electronics Co., Ltd. Agent Patent Attorney Masu 1) Takeo @6EKIA No. 7m

Claims (1)

[Scope of Claims] 1. In a display device that emits light by leaking the propagating light of the optical waveguide to the outside in the middle of an optical waveguide having a translucent property designed to confine light, the optical waveguide is electrically The optical waveguide is formed of an optical member, and includes a distributed electric field application means that applies a distributed electric field to the middle part of the optical waveguide to change the refractive index and generate an equivalent prism, A display device characterized in that the light propagating in the optical waveguide leaks to the outside of the optical waveguide and emits light by passing through an equivalent prism generated by the distributed electric field applying means.