JPH06214217A - Image display device - Google Patents

Abstract

PURPOSE:To provide the image display device of a high-contrast which can be utilized as a direct viewing type image display device as well and has high light transmittance and sufficient light shieldability. CONSTITUTION:This image display device is constituted by laminating panels 4 to 8 which have plural pixels capable of electrically controlling a scattering state and nonscattering state of light, an optically transparent layer 2 which consists of plural optically transparent bodies 2 allowing the transmission of rays progressing in the direction perpendicular to the panels 4 to 8, are provided with light absorptive parts 3 on the respective flanks or boundary parts of the optically transparent bodies 2 and can absorb the rays progressing in the directions not perpendicular to the panels 4 to 8 and a transmission scattering layer 1 which can scatter the rays transmitted through the optically transparent layer 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a display panel of a measuring instrument,
The present invention relates to an image display device having a plurality of pixels used for a computer image display device, a television and the like.

[0002]

SUMMARY OF THE INVENTION The present invention is a panel having a plurality of pixels capable of electrically controlling a light scattering state and a non-scattering state; for example, a light absorbing portion is formed at a portion corresponding to a boundary between pixels. However, a light ray traveling perpendicularly to the panel is transmitted, and a light ray traveling at an angle with it reaches the light absorbing portion and is absorbed, and the light ray transmitted through the optical transparent layer is scattered. The present invention relates to an image display device in which a transmitted light scattering layer that can be used is arranged. By adopting such an arrangement, incident light scattered in the panel is absorbed by the light absorbing portion, so that it does not reach the light transmitting / scattering layer.
The incident light that has not been scattered in the panel reaches the transmitted light scattering layer and is then scattered and emitted. Therefore, it is possible to greatly change the amount of light scattered and emitted from the transmitted light scattering layer by controlling the scattering and non-scattering of light in the panel, and it is possible to display an image with high contrast on the transmitted light scattering layer. it can.

[0003]

2. Description of the Related Art A thin film transistor (TF) is currently used as a high-definition image display device having features of small size, light weight, and power saving.
Twisted nematic (TN) liquid crystal panels by the active matrix driving method and super twisted nematic (STN) liquid crystal panels by the simple matrix driving method have been put into practical use. However, in the image display using these liquid crystal panels, it is necessary to dispose polarizing plates on the entrance surface and the exit surface of the panel and convert the light into linearly polarized light for use, so that the light utilization efficiency is low. Further, it has a disadvantage that it is difficult to display an image having a high viewing angle characteristic. For these reasons, recently, as a method of displaying an image with high light utilization efficiency and excellent viewing angle characteristics, a light scattering state and a non-scattering state of a polymer dispersed liquid crystal (PDLC) panel or the like are electrically controlled. Image display devices using possible liquid crystal panels have been attracting attention. However, these liquid crystal panels are mainly used as a transmissive type in order to obtain an image display having a high contrast, and it has been considered difficult to cope with a small-sized, lightweight direct-view type image display device.

In an image display device having a plurality of pixels capable of electrically controlling the scattering state and the non-scattering state of light and displaying the image by controlling the scattering state of each pixel,
It is difficult to obtain a sufficient light-shielding property in the scattered state while showing a high light transmittance in the non-scattered state. Therefore, an image display having high contrast has not been obtained as a direct-view image display device. On the other hand, there has been attempted a method of obtaining a high contrast by projecting a display image on a panel through a Schlieren optical system and then projecting it on a screen. However, in the above method, it is necessary to provide a large optical system on the light emitting surface side of the panel, and it is difficult to reduce the size and weight.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a high contrast image display device having a high light transmittance and a sufficient light shielding property, which can be used as a direct-view image display device. Further, the present invention is to provide a device which is downsized and lightened as the above device.

[0006]

[Means for Solving the Problems] The above problems are solved,
In explaining that it is possible to realize a small and lightweight direct-viewing type image display device, a polymer is used as a panel having a plurality of pixels and electrically controlling a light scattering state and a non-scattering state. An active matrix liquid crystal display device using a dispersed liquid crystal (hereinafter referred to as PDLC) panel is used as an example. It should be noted that the pixel referred to here represents, for example, one structural portion on a panel in which one pixel electrode 7, pixel driving element 8 and black matrix 6 are combined as one set in FIG.

In FIG. 1, parallel rays are made incident from the left through the panel substrate 4. Of the incident rays that have reached the PDLC layer 5, those that are not scattered by the PDLC layer 5 are propelled to the right in the optically transparent layer 2 as shown by the solid arrow in the figure, and scattered after passing through the transmitted light scattering layer 1. It becomes light and goes out to the outside world. On the other hand, among the incident light rays, a light ray group whose light is scattered by the PDLC layer and whose traveling direction is changed is incident on the light absorbing portion 3 formed in the optical transparent layer 2 as shown by a dashed arrow in the figure. In order to absorb light, it does not reach the transmitted light scattering layer 1 and does not emit to the outside. That is, if the PDLC layer 5 is controlled to the light-scattering state, "dark" display can be performed, and if the PDLC layer 5 is controlled to the non-scattering state, "light" display can be performed on the light-transmitting scattering layer 1.

By using this principle and electrically controlling the transmission state and the scattering state of light for each pixel on the PDLC panel, a high-definition image with a high contrast of light and dark is formed on the transmitted light scattering layer 1. Can be displayed, and a small and lightweight light-transmissive direct-view display can be realized. More specifically, the light absorption portion 3 can be formed at a position corresponding to a boundary portion between pixels in the optically transparent layer 2, but is not necessarily limited to this. In particular, when the optical transparent layer is composed of a transparent columnar body group having a cross section smaller than the pixel area, an absorbing part can be provided on the side surface of the columnar body or between the columnar bodies.

As described above, the optically transparent layer has a kind of honeycomb structure, and its wall portion has a light absorbing property.

The light absorbing portion 3 may be formed of a polymer resin containing a dye having a light absorbing property, or may be formed of a polymer resin or a metal whose surface is treated to have a light absorbing property. good.

The light transparent layer having the light absorbing portion can be formed, for example, by the following method.

1) The optically transparent portion other than the light absorbing portion is formed by using an ultraviolet curable resin. The light absorbing portion is formed of a thermosetting resin containing a light absorbing dye, or a light absorbing dye only.

A screen with a mask that completely shields light from the boundary between pixels where the light absorbing portion is formed and transmits light to the other portions is used. As shown in FIG. 2, a monomer liquid of an ultraviolet curable resin is injected onto the substrate and adjusted so that the liquid layers have the same thickness. When this is irradiated with ultraviolet light through the above-mentioned screen with a mask, only the resin monomer in the portion where the ultraviolet ray is transmitted is cured, and the light-shielded portion remains in the monomer state because the ultraviolet light does not reach.
The thickness of the cured product is controlled by repeating the steps of injecting the monomer liquid and ultraviolet curing. As the substrate, the panel substrate 4 or the light transmission / scattering layer 1 may be used.

After this step, the uncured monomer is washed off with a solvent so that only the cured product remains on the substrate. Then, by a vacuum injection method, after injecting a thermosetting resin monomer containing a light absorbing dye into the voids of the cured product, heat curing is performed or the light absorbing dye dispersed in a solvent is placed in the voids of the cured product. By repeating the step of injecting and volatilizing the solvent several times to deposit the light absorbing dye layer in the void, the light transparent layer having the light absorbing portion can be formed.

2) A side of an optical fiber having a diameter corresponding to the size of a pixel or smaller than that is coated with a resin containing a light-absorbing dye is bundled and fixed, or in a space between the bundled fibers. A thermosetting resin containing a light-absorbing dye may be injected and then heat-cured. A composition suitable for this application can be prepared by cutting the above-mentioned formed body by an appropriate method in accordance with the thickness required for the light transparent layer having the light absorbing portion. In this case, if an optical fiber having a diameter much smaller than the pixel area is used, a large number of optical transparent bodies will correspond to one pixel, and the positioning will be very simple.

3) In a state where the polymer dispersed liquid crystal 5 is not injected into the gap between the two panel substrates 4, an ultraviolet curable resin monomer liquid is applied onto the panel substrate on the light emitting surface side (right side in FIG. 1). The thickness of the injected liquid layer is adjusted as necessary. In this state, ultraviolet rays are irradiated from the panel substrate side on the light incident surface side (left side in FIG. 1).

At this time, if the black matrix 6 is formed so as to correspond to the position of the light absorption portion, the black matrix 6 blocks the incident ultraviolet light, so that only the portion where the black matrix 6 is not formed receives light. A transparent cured body is formed. After that, the uncured monomer is removed in the same manner as in the above-mentioned method (1), and then the light absorbing portion is formed, whereby a constituent suitable for the present application can be prepared.

The optical transparent layer 2 having the light absorbing portion 3 can be adhered to the transmitted light scattering layer 1 or the panel substrate 4 with a polymer adhesive.

The optically transparent layer 2 may be an air layer, a polymer resin layer, or glass. The distance between the panel substrate 4 and the transmitted light scattering layer 1 is determined in consideration of the trade-off between the required display contrast and display brightness. Generally, the longer the distance, the higher the display contrast. The display brightness of "bright" decreases. The transmitted light scattering layer 1 may be an optically transparent material having a light-scattering property obtained by treating the surface thereof, and a polymer resin may be used as the material thereof, or a frosted glass plate or the like may be used. Light transmission / scattering layer 1
It is preferable that the surface on the light emission side of (1) is subjected to a light reflection preventing treatment or a protective layer subjected to a light reflection preventing treatment is formed.

As the panel substrate 4, either a glass substrate or a polymer resin substrate may be used as long as it is optically transparent.

The driving method of the panel may be either a simple matrix or an active matrix, and the method used for a normal liquid crystal panel can be used.
When the simple matrix drive method is used, the pixel electrode 4 portion in this description can correspond to the area portion where the row electrode and the column electrode intersect.

Further, similarly to a normal liquid crystal display device, it is possible to colorize a display image by providing three kinds of color filters of red, green and blue corresponding to each pixel.

In this case, the color filter layer may be formed on the panel substrate, the transmitted light scattering layer 1 or at other positions.

In the present description, polymer dispersed liquid crystal (PDL) is used as means for electrically controlling the scattered state and the non-scattered state of light.
C) is mentioned as an example. Polymer dispersed liquid crystal is a polymer that has a remarkable light scattering ability due to the difference in refractive index between the resin matrix and the liquid crystal and the spatial distortion of the director of each liquid crystal domain. It refers to a liquid crystal composite. When the liquid crystal molecules are oriented in one direction by applying an external electric field to the PDLC layer, the difference in refractive index with the resin matrix, the distortion of the director, and the like disappear, so that the PDLC layer does not lose its light-scattering ability. It shows the light transmittance. As described above, since the PDLC panel can reversibly control the scattered state and the non-scattered state of light depending on the presence or absence of an externally applied voltage, the PDLC panel can be used in the image display device of the present application.

Of course, the panel is not limited to this PDLC panel, and any panel that can control the scattered state and the non-scattered state of light can be used. For example, a cholesteric-nematic phase transition type liquid crystal panel or a liquid crystal panel utilizing a dynamic scattering mode of liquid crystal can be used.

[0026]

As described above, a panel having a plurality of pixels capable of electrically controlling the scattering state and the non-scattering state of light according to the present invention; the portion corresponding to the boundary between pixels Alternatively, by arranging a light transmitting layer having a light absorbing portion formed in a portion not corresponding thereto; and a transmitted light scattering layer, it is possible to display an image having high light utilization efficiency and high contrast while being small and lightweight. , It is now possible to supply a direct-view type image display device.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing the structure of the present invention.

FIG. 2 shows an example of a method for forming an optically transparent layer of the present invention.

[Explanation of symbols]

 1. Light transmission / scattering layer 2. Optically transparent layer 3. Light absorbing section 4. Panel substrate 5. Polymer dispersed liquid crystal (PDLC) 6. Black matrix 7. Pixel electrode 8. Pixel drive element 9. Optically transparent layer 11. Screen with mask 12. UV curable resin 13. Substrate 14. Movable pedestal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Nakatani 4-3-2 Asahigaoka, Hino-shi, Tokyo Inside Teijin Ltd. Tokyo Research Center

Claims (5)

[Claims] 1. A panel having a plurality of pixels capable of electrically controlling a scattering state and a non-scattering state of light; comprising a plurality of optical transparent bodies transmitting a light ray traveling in a direction perpendicular to the panel. An optical transparent layer having a light absorbing portion provided on each side surface or boundary portion of the optical transparent body and capable of absorbing a light ray traveling in a direction not perpendicular to the panel; and transmitting through the optical transparent layer. An image display device in which a transmission / scattering layer that can scatter light rays is laminated. 2. The optical transparent body is a transparent columnar body that extends in a direction perpendicular to the panel, and a cross-sectional area of a cut of the columnar body parallel to the panel is substantially the same as or smaller than that of the pixel. The image display device according to claim 1. 3. The panel according to claim 1, wherein the panel comprises a polymer matrix containing a liquid crystal phase in which liquid crystal molecules are dispersed in a droplet form or a three-dimensional network form, and a pixel electrode for giving an electric signal thereto. The image display device described. 4. The image display device according to claim 3, wherein the liquid crystal phase contains dichroic dye molecules having different light absorption properties depending on the directions of the molecular axes. 5. The image display device according to claim 1, wherein three types of color filters of red, green and blue are provided corresponding to the pixels to enable color display.