JPH02106791A - Display device - Google Patents

Abstract

PURPOSE:To provide the display device which can be formed to the larger size, has good light absorptivity of a dark part, produces high contrast and is suitable for an outdoor display as well by selectively bringing members having different refractive indices into contact with each other, thereby controlling the state of the total reflection of a reflecting surface. CONSTITUTION:This display device is so constituted that one surface of a light guide member 3 is directed to the reflecting surface 4 and is irradiated with illumination light 2 and that an observer 1 observes the reflected light thereof. The reflecting surface 4 and a light absorbing member 6 face each other via a gap 9. A working liquid 7 of a control member exists in the gap so as to selectively fill the spacing between the reflecting surface 4 and the light absorbing surface 8. The reflected light can be observed from the direction near an exist angle 11 in the part where the working liquid does not exist and the illumination light is not totally reflected and is reflected by the light absorbing surface 8 so as to arrive at the observer in the part where the working liquid is filled, when the illumination light is introduced from near the incident surface 10 to the reflecting surface 4 if the working liquid is water and the light guide member is a resin having the refractive index of a prescribed value. The light or the color corresponding to the spectral distribution of the illumination light and the spectral absorption characteristic of the light absorbing surface or black color is therefore, observed. The image display of the high contrast is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a display device that converts electrical signals into image information and displays the image information.

[Conventional technology]

CRTs, liquid crystal display devices, and the like are known as display devices.

[Problem to be solved by the invention]

In conventional display devices, CRT is a light-emitting display device, so it is difficult to obtain sufficient contrast when used outdoors, and a large device with an angle of view of, for example, more than 1 meter cannot be constructed in practice. It had a point. Furthermore, liquid crystal devices have the problem of difficulty in ensuring contrast.

An object of the present invention is to solve these problems and provide a display device that can be made large, has good light absorption in dark areas, can achieve high contrast, and is suitable for outdoor display.

[Means to solve the problem]

The display device of the present invention has a light guide member having at least one reflective surface, and a light transmitting member is selectively brought into contact with a part of the reflective surface to control the total reflection state of the reflective surface. The feature is that the display is configured so that the display is performed by doing the following.

[Effect]

In the above configuration of the present invention, display is performed by a change in the amount of reflected light that occurs by utilizing a change in the critical angle of total reflection caused by the presence or absence of a control member in contact with the reflective surface.

〔Example〕

Next, the present invention will be explained based on examples. FIG. 1 is a schematic diagram showing the operating principle of the present invention. In the same figure, one surface of the light guide member 3 is a reflective surface 4, and illumination light 2 is directed toward the reflective surface.
, and the reflected light 5 of this light is observed by an observer. A light absorbing member 6 faces the reflective surface 4 through a gap 9, and a control member, in this case a working liquid 7, is present in the gap so as to selectively fill the space between the reflective surface 4 and the light absorbing surface 8. .

In the above configuration, the working liquid is water and the light guide member has a refractive index of 1.
．． The operation will be explained in the case of No. 58 resin. The refractive index of resin, air, and water are 1.58, 1.0, and 1.33, respectively.
It is. Therefore, total internal reflection occurs when light exits from a member with a high refractive index to a member with a low refractive index, and the angle of incidence (critical angle) at which total internal reflection occurs in each case is 55.4 degrees between water and resin; 55.4 degrees between air and resin. 39. Twice. First, illumination light is introduced into the reflective surface 4 from an incident angle (indicated by 10 in the figure) of around 47 degrees. When an observer observes a portion where no working liquid is present from a direction near the emission angle (indicated by 11 in the figure) of 47 degrees, reflected light can be observed. Next, in the area filled with the working liquid, the above incident angle is smaller than the critical angle of total reflection, so the illumination light is not totally reflected, but is reflected by the light absorption surface 8 via the working liquid and reaches the viewer. (Indicated by optical path 12) Therefore, a colored light or black color is observed depending on the spectral distribution of the illumination light and the spectral absorption characteristics of the light absorption surface.

Next, an embodiment of a display device based on the above operating principle will be described.

In FIG. 2, a light guide member 21 having a plurality of prism-like protrusions and a light absorbing member 24 are arranged with a gap therebetween.

A plurality of transparent electrodes 22 to which a voltage can be selectively applied are formed on the gap surface of the light guiding member 21. An electrode layer 23 is formed on the opposing surface of the control member 24, and this surface is blackened and has sufficient light absorption. An insulating liquid (for example, isoparaffin solvent, etc.) 25 is filled in the gap as a working liquid. A three-color filter 26 of R, G, and B is formed on one surface of the prism-like protrusion, and is illuminated with white illumination light 27. In the above configuration, by applying a voltage to the electrode at a desired position, the working liquid is attracted by Maxwell's stress and comes into contact with the light guiding member, and the illumination light is absorbed on the surface of the light absorbing member. Therefore, a color image can be displayed by controlling the reflected light from the reflective surface of a desired color at a desired position.

FIG. 3 shows a second embodiment. The light guiding member 35 and the light absorbing member 37 are opposed to each other with a gap 36 interposed therebetween, and a heat-shrinkable polymer 38 is sealed in the gap as a working liquid. (For example, PV
A partition 33 is provided inside the cavity 36 (eg, a gelled polymer material irradiated with gamma rays of an ME aqueous solution), and a heat generating element 32 is provided therein. A cooling liquid 31 is circulated on the back surface of the light absorbing member 37. In the above configuration, by driving a desired heating element, the working liquid within the partition is heated and selectively contracts. In other parts, the working liquid expands and fills the space between the light guiding member and the light absorbing member.

Therefore, total reflection occurs at the contracted portion and an image is displayed.

FIG. 4 shows another embodiment. In this embodiment, a working liquid containing water as a main component is locally vaporized by selective heating to cause reflection. That is, the light guiding member 42 and the light absorbing member 45
A plurality of heating elements 43, each of which can be independently energized, are provided with a working liquid 41 sealed therebetween. Bubbles 44 are generated only in the heating section, and total reflection occurs.

FIG. 5 shows yet another embodiment. A plurality of control members 51 made of urethane rubber are movably supported by piezoelectric drive elements 52, and only the portions that are in contact with the front cover 53 are illuminated with illumination light 54 from the back side. A display device with a wide viewing angle can be constructed by providing diffusivity to the front cover surface.

As explained above, since the device of the present invention displays an image by bringing the control member into contact with the reflective surface of the light guide member, an oil-based magnetic fluid may be used to move the control member in addition to the method described above. Various methods can be used, such as controlling the magnetic field used to selectively raise the aqueous transparent liquid.

Further, the incident angle and the output angle can be set without being limited to the above values depending on the refraction characteristics of the materials involved and the characteristics of the light emitting element.

〔Effect of the invention〕

As described above, according to the above structure of the present invention, since the display is performed by a critical angle change occurring on the reflective surface, it is possible to display an image with high contrast.

It also has the effect that any color can be displayed by selecting the color of the reflective surface. Furthermore, since a light-receiving type display device can be constructed, an outdoor display device can be realized. Furthermore, since the state retention time of the control member is long, it is possible to realize a still image display device having memory properties.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the operating principle of the display device of the present invention. FIG. 2 is a sectional view of a display device showing an embodiment of the present invention. FIG. 3 is a sectional view of a display device showing another embodiment of the present invention. FIG. 4 is a sectional view of a display device showing still another embodiment of the present invention. FIG. 5 is a sectional view of a display device showing still another embodiment of the present invention. 2.27 Illumination light 3.21.35.42.53 Light guide member 4 Reflective surface 6.24.37.45 Light absorption member 7.25.38.41.51 Control member and above Applicant: Seiko Epson Co., Ltd. Agent Patent attorney Kizobe Suzuki and 1 other person

Claims (1)

[Scope of Claims] A light guiding member having at least one reflective surface, a member having a refractive index different from that of the light guiding member is selectively brought into contact with a part of the reflective surface, and all of the reflective surface is A display device characterized in that it is configured to perform display by controlling the state of reflection.